WorldWideScience

Sample records for void formation behavior

  1. The void galaxy survey: Star formation properties

    NARCIS (Netherlands)

    Beygu, B.; Kreckel, K.; van der Hulst, J. M.; Jarrett, T. H.; Peletier, R.; van de Weygaert, R.; van Gorkom, J. H.; Aragon-Calvo, M. A.

    2016-01-01

    We study the star formation properties of 59 void galaxies as part of the Void Galaxy Survey (VGS). Current star formation rates are derived from H α and recent star formation rates from near-UV imaging. In addition, infrared 3.4, 4.6, 12 and 22 μm Wide-field Infrared Survey Explorer emission is

  2. Analysis of void formation in thermoplastic composites during resistance welding

    NARCIS (Netherlands)

    Shi, H.; Fernandez Villegas, I.; Bersee, H.E.N.

    2016-01-01

    The process-induced voids during resistance welding of glass fabric-reinforced polyetherimide was investigated. The mechanisms of void formation in adherends, in particular, the residual volatile-induced voids and the fibre de-compaction-induced voids, were analysed. Due to the non-uniform

  3. Formation of Voids from Negative Density Perturbations

    Science.gov (United States)

    de Araujo, J. C. N.; Opher, R.

    1990-11-01

    RESUMEN. Se estudia la formaci6n de huecos a partir de un espectro negativo de perturbaciones, tomando en cuenta la expansi6n del Universo, arrastre por fotones, enfriamiento por fotones, fotoionizaci6n, ioniza- ci6n colisional, enfriamiento Lyman a y la formaci6n y enfriamiento de moleculas H2. Nuestros resultados predicen la existencia de regiones 1/10 de Ia densidad promedio para regiones de masa lO - 1O10M . ABSTRACT. In the present paer we study the formation of voids from a negative spectrum of perturbations taking into account the expansion of the Universe, photon-drag, photon-cooling, photoionization, collisional ionization, Lyman a cooling and the formation and cooling of 112 molecules. Our results predict the existence of regions 1/10 the average density for regions of mass 1O - 1O10M@ : CLUSTERS-GALAXIES - COSMOLOGY

  4. Granular Eruptions: Void Collapse and Jet Formation

    NARCIS (Netherlands)

    Mikkelsen, R.; Versluis, Andreas Michel; Koene, Elmer; Bruggert, Gert-Wim; van der Meer, Roger M.; van der Weele, J.P.; Lohse, Detlef

    2002-01-01

    Upon impact, sand is blown away in all directions, forming a splash. The ball digs a cylindrical void in the sand and the jet is formed when this void collapses: The focused sand pressure pushes the jet straight up into the air. When the jet comes down again, it breaks up into fragments, i.e.,

  5. Structural control of void formation in dual phase steels

    DEFF Research Database (Denmark)

    Azuma, Masafumi

    The objective of this study is to explore the void formation mechanisms and to clarify the influence of the hardness and structural parameters (volume fraction, size and morphology) of martensite particles on the void formation and mechanical properties in dual phase steels composed of ferrite...... measurements, tensile tests and hole-expansion tests. The initial microstructure and the deformed microstructure were characterized by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In situ tensile tests in a SEM were applied for direct observation of the void formation...... of the martensite accelerates the void formation in the martensite by enlarging the size of voids both in the martensite and ferrite. It is suggested that controlling the hardness and structural parameters associated with the martensite particles such as morphology, size and volume fraction are the essential...

  6. Nonlinear theory of void formation in colloidal plasmas.

    Science.gov (United States)

    Avinash, K; Bhattacharjee, A; Hu, S

    2003-02-21

    A nonlinear time-dependent model for void formation in colloidal plasmas is proposed. For experimentally relevant initial conditions, the model describes the nonlinear evolution of a zero-frequency linear instability that grows rapidly in the nonlinear regime and subsequently saturates to form a void. A number of features of the model are consistent with experimental observations under laboratory and microgravity conditions.

  7. Void formation in ODS EUROFER produced by hot isostatic pressing

    Energy Technology Data Exchange (ETDEWEB)

    Ortega, Y.; Monge, M.A.; Munoz, A.; Leguey, T.; Pareja, R. [Madrid Univ. Carlos-3, Dept. de Fisica (Spain); Castro, V. de [Oxford Univ., Dept. of Materials (United Kingdom)

    2007-07-01

    for positrons trapped in voids. Unmilled EUROFER and the EUROFER plate did not show this behavior attributed to the formation of voids induced by annealing. The results indicate that the milling damage retained in the HIPed material has the capability to cluster into voids and growth by heating. These voids appear to be stable upon annealing 1323 K. (authors)

  8. Molecular Gas and Star Formation in Void Galaxies

    Science.gov (United States)

    Das, M.; Saito, T.; Iono, D.; Honey, M.; Ramya, S.

    2016-10-01

    We present the detection of molecular gas using CO(1-0) line emission and followup Hα imaging observations of galaxies located in nearby voids. The CO(1-0) observations were done using the 45m telescope of the Nobeyama Radio Observatory (NRO) and the optical observations were done using the Himalayan Chandra Telescope (HCT). Although void galaxies lie in the most underdense parts of our universe, a significant fraction of them are gas rich, spiral galaxies that show signatures of ongoing star formation. Not much is known about their cold gas content or star formation properties. In this study we searched for molecular gas in five void galaxies using the NRO. The galaxies were selected based on their relatively higher IRAS fluxes or Hα line luminosities. CO(1-0) emission was detected in four galaxies and the derived molecular gas masses lie between (1 - 8)×109 M⊙. The Hα imaging observations of three galaxies detected in CO emission indicates ongoing star formation and the derived star formation rates vary between from 0.2 - 1.0 M7odot; yr -1, which is similar to that observed in local galaxies. Our study shows that although void galaxies reside in underdense regions, their disks may contain molecular gas and have star formation rates similar to galaxies in denser environments.

  9. Conclusive evidence of abrupt coagulation inside the void during cyclic nanoparticle formation in reactive plasma

    Energy Technology Data Exchange (ETDEWEB)

    Wetering, F. M. J. H. van de; Nijdam, S.; Beckers, J. [Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands)

    2016-07-25

    In this letter, we present scanning electron microscopy (SEM) results that confirm in a direct way our earlier explanation of an abrupt coagulation event as the cause for the void hiccup. In a recent paper, we reported on the fast and interrupted expansion of voids in a reactive dusty argon–acetylene plasma. The voids appeared one after the other, each showing a peculiar, though reproducible, behavior of successive periods of fast expansion, abrupt contraction, and continued expansion. The abrupt contraction was termed “hiccup” and was related to collective coagulation of a new generation of nanoparticles growing in the void using relatively indirect methods: electron density measurements and optical emission spectroscopy. In this letter, we present conclusive evidence using SEM of particles collected at different moments in time spanning several growth cycles, which enables us to follow the nanoparticle formation process in great detail.

  10. Reactivity effects of void formations in a solution critical assembly

    Energy Technology Data Exchange (ETDEWEB)

    Walters, Steven G. [Univ. of New Mexico, Albuquerque, NM (United States)

    1994-01-01

    SHEBA II (Solution High Energy Burst Assembly) was constructed in order to better understand the neutronics of solutions of fissile materials. In order to estimate the effect on criticality from the formation of bubbles, models were devised in MCNP (Monte Carlo Neutron Photon transport code) and THREEDANT (THREE dimensional, Diffusion-Accelerated, Neutral-Particle Transport). It was found that the formation of voids in all but the outside bottom edge of the assembly cylinder tend to act as a negative insertion of reactivity. Also, an experiment has been designed which will verify the results of the codes.

  11. Void formation and its impact on Cu−Sn intermetallic compound formation

    Energy Technology Data Exchange (ETDEWEB)

    Ross, Glenn, E-mail: Glenn.Ross@aalto.fi; Vuorinen, Vesa; Paulasto-Kröckel, Mervi

    2016-08-25

    Void formation in the Cu−Sn system has been identified as a major reliability issue with small volume electronic interconnects. Voids form during the interdiffusion of electrochemically deposited Cu and Sn, with varying magnitude and density. Electroplating parameters include the electrolytic chemistry composition and the electroplating current density, all of which appear to effect the voiding characteristics of the Cu−Sn system. In addition, interfacial voiding affects the growth kinetics of the Cu{sub 3}Sn and Cu{sub 6}Sn{sub 5} intermetallic compounds of the Cu−Sn system. The aim here is to present voiding data as a function of electroplating chemistry and current density over a duration (up to 72 h) of isothermal annealing at 423 K (150 °C). Voiding data includes the average interfacial void size and average void density. Voids sizes grew proportionally as a function of thermal annealing time, whereas the void density grew initially very quickly but tended to saturate at a fixed density. A morphological evolution analysis called the physicochemical approach is utilised to understand the processes that occur when a voided Cu/Cu{sub 3}Sn interface causes changes to the IMC phase growth. The method is used to simulate the intermetallic thickness growths' response to interfacial voiding. The Cu/Cu{sub 3}Sn interface acts as a Cu diffusion barrier disrupting the diffusion of Cu. This resulted in a reduction in the Cu{sub 3}Sn thickness and an accelerated growth rate of Cu{sub 6}Sn{sub 5}. - Highlights: • Average void size is proportional linearly to thermal annealing time. • Average void density grows initially very rapidly followed by saturation. • Voids located close to the Cu/Cu{sub 3}Sn interface affect IMC growth rates. • Voids act as a diffusion barrier inhibiting Cu diffusion towards Sn. • Voids located at the interface cause Cu{sub 3}Sn to be consumed by Cu{sub 6}Sn{sub 5}.

  12. Resin flow and void formation in an autoclave cure cycle

    Science.gov (United States)

    Lionetto, Francesca; Lucia, Massimo; Dell'Anna, Riccardo; Maffezzoli, Alfonso

    2016-05-01

    A finite element (FE) model able to evaluate both the evolution of resin flow, degree of reaction and void formation during autoclave cure cycles was developed. The model was implemented using a commercial epoxy matrix widely used in aeronautic field. The FE model also included a kinetic and rheological model whose input parameters were experimentally determined by Differential Scanning Calorimetry and rheological analysis. The FE model was able to predict the evolution of degree of reaction with very good agreement with the experimental data. Moreover, the predicted resin losses were lower than 3% of the overall composite resin content.

  13. Vacancy Migration and Void Formation in gamma-irradiated Ice

    DEFF Research Database (Denmark)

    Eldrup, Morten Mostgaard

    1976-01-01

    are ascribed to Ps inhibition and conversion by radiation created OH radicals. Heating above −165°C makes both effects disappear in agreement with radiation chemistry results on OH. Heating also increases the longest lifetime up to 11 nsec at −130°C. This is explained as vacancy migration leading to void...... formation. A vacancy migration energy is obtained, Em=0.34±0.07 eV, around three times higher than the previously assumed value. The advantage in this kind of study of using PAT, which are specifically sensitive to vacancy type defects, is pointed out....

  14. Void formation induced electrical switching in phase-change nanowires.

    Science.gov (United States)

    Meister, Stefan; Schoen, David T; Topinka, Mark A; Minor, Andrew M; Cui, Yi

    2008-12-01

    Solid-state structural transformation coupled with an electronic property change is an important mechanism for nonvolatile information storage technologies, such as phase-change memories. Here we exploit phase-change GeTe single-nanowire devices combined with ex situ and in situ transmission electron microscopy to correlate directly nanoscale structural transformations with electrical switching and discover surprising results. Instead of crystalline-amorphous transformation, the dominant switching mechanism during multiple cycling appears to be the opening and closing of voids in the nanowires due to material migration, which offers a new mechanism for memory. During switching, composition change and the formation of banded structural defects are observed in addition to the expected crystal-amorphous transformation. Our method and results are important to phase-change memories specifically, but also to any device whose operation relies on a small scale structural transformation.

  15. On the formation of voids in internal tin Nb3Sn superconductors

    CERN Document Server

    Scheuerlein, C; Haibel, A

    2007-01-01

    In this article we describe three void growth mechanisms in Nb3Sn strands of the internal tin design on the basis of combined synchrotron micro-tomography and x-ray diffraction measurements during in-situ heating cycles. Initially void growth is driven by a reduction of void surface area by void agglomeration. The main void volume increase is caused by density changes during the formation of Cu3Sn in the strand. Subsequent transformation of Cu-Sn intermetallics into the lower density a-bronze reduces the void volume again. Long lasting temperature ramps and isothermal holding steps can neither reduce the void volume nor improve the chemical strand homogeneity prior to the superconducting A15 phase nucleation and growth.

  16. Void formation in ODS EUROFER produced by hot isostatic pressing

    Energy Technology Data Exchange (ETDEWEB)

    Ortega, Y. [Departamento de Fisica, Universidad Carlos III de Madrid, 28911 Leganes (Spain)], E-mail: yanicet@fis.ucm.es; Monge, M.A. [Departamento de Fisica, Universidad Carlos III de Madrid, 28911 Leganes (Spain); Castro, V. de [Department of Materials, University of Oxford, Oxford OX1 3PH (United Kingdom); Munoz, A.; Leguey, T.; Pareja, R. [Departamento de Fisica, Universidad Carlos III de Madrid, 28911 Leganes (Spain)

    2009-04-30

    Positron annihilation experiments were performed on oxide dispersion strengthened (ODS) and non-ODS EUROFER prepared by mechanical alloying and hot isostatic pressing. The results revealed the presence of small voids in these materials in the as-HIPed conditions. Their evolution under isochronal annealing experiments was investigated. The coincidence Doppler broadening spectra of ODS EUROFER exhibited a characteristic signature attributed to positron annihilation in Ar-decorated voids at the oxide particle/matrix interfaces. The variation of the positron annihilation parameters with the annealing temperature showed three stages: up to 623 K, between 823 and 1323 K, and above 1323 K. In the temperature range 823-1323 K void coarsening had effect. Above 1323 K some voids annealed out, but others, associated to oxide particles and small precipitates, survived to annealing at 1523 K. Transmission electron microscopy observations were also performed to verify the characteristics of the surviving defects after annealing at 1523 K.

  17. Effect of hardness of martensite and ferrite on void formation in dual phase steel

    DEFF Research Database (Denmark)

    Azuma, M.; Goutianos, Stergios; Hansen, Niels

    2012-01-01

    The influence of the hardness of martensite and ferrite phases in dual phase steel on void formation has been investigated by in situ tensile loading in a scanning electron microscope. Microstructural observations have shown that most voids form in martensite by evolving four steps: plastic...... deformation of martensite, crack initiation at the martensite/ferrite interface, crack propagation leading to fracture of martensite particles and void formation by separation of particle fragments. It has been identified that the hardness effect is associated with the following aspects: strain partitioning...... between martensite and ferrite, strain localisation and critical strain required for void formation. Reducing the hardness difference between martensite and ferrite phases by tempering has been shown to be an effective approach to retard the void formation in martensite and thereby is expected to improve...

  18. Improving The Voided Reinforced Concrete Beams Behavior by Strenthining The Compression Zone Concrete Using Polyvinyl Alcohol

    Directory of Open Access Journals (Sweden)

    Nabeel Hasan Ali Al-Salim

    2018-02-01

    Full Text Available  Determining dimensions of  continuous RC beam depend on the critical span. Practically, changing the dimensions of others spans is difficult. So that, this work aimed to discuss the possibility of adding voids within the beams which its dimensions are more than required in order to reduce the cost and dead load. The selected percent of voids to volume of  tested  beams was 10%.  The shape of voids was a first variable (spherical voids or conic voids. Also, the alteration in behavior when a (5cm concrete layer thickness of compression zone was replaced with a concrete layer modified with adding polyvinyl alcohol (PVA was investigated, as a second variable. After testing six samples, the result showed that the failure criteria of normal concrete voided beams is transformed from flexural behavior to shear behavior, while the failure criteria of control solid specimen was flexure behavior. Also, the modified beams failed in flexural behavior except the beam with conic voids failed in shear behavior. Corresponding to this transform, the ultimate load varied in the same manner. Where, the normal concrete voided beams failed with lesser ultimate load than control solid beam of about (6.4% and 18.3% for spherical and conic voids, respectively. While, the ultimate load of modified concrete beams is increased of about (13.8%, 5.4% and 3.1% for solid beam, spherical and conic voided beams respectively in comparing control specimen.

  19. Study on the formation of micro-voids during ductile fracture

    Science.gov (United States)

    Long, Shao-Lei; Liang, Yi-Long; Lu, Ye-Mao; Yang, Ming; Yin, Cun-Hong

    2018-01-01

    In this work, the formation of micro-voids for ductile fracture has been discussed with regards to the classical nucleation theory from the phase transformation in 20CrNi2Mo steel. The differences in them were determined based upon the driving force and the resistance. In terms of tensile load, the driving force was the energy of tensile load before necking, while the resistance was the surface energy from the formation of mass of micro-voids, as determined by the fracture toughness instead of the phase transformation. Finally, the relationship between the formation of micro-voids and the macroscopic properties was discussed. The results illustrated that the formation of micro-voids depended on the elastic-plastic energy and on the yield strength represented by r* (the critical formation radius) and {{Δ }}{G}* (the critical formation energy). These results were confirmed from r 1* (with the experiment) and r 2* (with the calculation). The work provided a novel way to study the relationship of micro-parameters and macro-properties. In addition, it was found that the critical formation diameter (2r*) of micro-voids was close to the width of martensite lath (d l).

  20. Influence of application techniques on contact formation and voids in anterior resin composite restorations.

    Science.gov (United States)

    Kwon, S R; Oyoyo, U; Li, Y

    2014-01-01

    This study evaluated the influence of three different application techniques on contact formation and voids in anterior resin composite restorations. Artificial ivorine teeth were randomly assigned to three experimental groups, with 20 specimens in each group. One operator performed all restorations using the Teflon tape, pull-through, or bioclear matrix technique. The treatment time required for each restoration was recorded. An examiner blinded to the treatment group performed the visual evaluation of six criteria, including proper contact formation. The restored teeth were cut to yield a total of 180 sections for microscopic evaluation. The Kruskal-Wallis procedure was performed to evaluate the significance of treatment time, number of voids, percent porosity area, and void diameter. There were significant differences in treatment time among the three groups (pdiastema closure (p0.05). However, the mean void diameter was greater with the bioclear matrix technique compared to the other two techniques (p<0.05).

  1. Detection of Molecular Gas in Void Galaxies : Implications for Star Formation in Isolated Environments

    Science.gov (United States)

    Das, M.; Saito, T.; Iono, D.; Honey, M.; Ramya, S.

    2015-12-01

    We present the detection of molecular gas from galaxies located in nearby voids using the CO(1-0) line emission as a tracer. The observations were performed using the 45 m single dish radio telescope of the Nobeyama Radio Observatory. Void galaxies lie in the most underdense parts of our universe and a significant fraction of them are gas rich, late-type spiral galaxies. Although isolated, they have ongoing star formation but appear to be slowly evolving compared to galaxies in denser environments. Not much is known about their star formation properties or cold gas content. In this study, we searched for molecular gas in five void galaxies. The galaxies were selected based on their relatively high IRAS fluxes or Hα line luminosities, both of which signify ongoing star formation. All five galaxies appear to be isolated and two lie within the Bootes void. We detected CO(1-0) emission from four of the five galaxies in our sample and their molecular gas masses lie between 108 and 109 M⊙. We conducted follow-up Hα imaging observations of three detected galaxies using the Himalayan Chandra Telescope and determined their star formation rates (SFRs) from their Hα fluxes. The SFR varies from 0.2 to 1 M⊙ yr-1 which is similar to that observed in local galaxies. Our study indicates that although void galaxies reside in underdense regions, their disks contain molecular gas and have SFRs similar to galaxies in denser environments. We discuss the implications of our results.

  2. Matrix Elasticity of Void-Forming Hydrogels Controls Transplanted Stem Cell-Mediated Bone Formation

    Science.gov (United States)

    Huebsch, Nathaniel; Lippens, Evi; Lee, Kangwon; Mehta, Manav; Koshy, Sandeep T; Darnell, Max C; Desai, Rajiv; Madl, Christopher M.; Xu, Maria; Zhao, Xuanhe; Chaudhuri, Ovijit; Verbeke, Catia; Kim, Woo Seob; Alim, Karen; Mammoto, Akiko; Ingber, Donald E.; Duda, Georg N; Mooney, David J.

    2015-01-01

    The effectiveness of stem-cell therapies has been hampered by cell death and limited control over fate1. These problems can be partially circumvented by using macroporous biomaterials that improve the survival of transplanted stem cells and provide molecular cues to direct cell phenotype2–4. Stem cell behavior can also be controlled in vitro by manipulating the elasticity of both porous and non-porous materials5–7, yet translation to therapeutic processes in vivo remains elusive. Here, by developing injectable, void-forming hydrogels that decouple pore formation from elasticity, we show that mesenchymal stem cell (MSC) osteogenesis in vitro, and cell deployment in vitro and in vivo, can be controlled by modifying, respectively, the hydrogel's elastic modulus or its chemistry. When the hydrogels were used to transplant MSCs, the hydrogel's elasticity regulated bone regeneration, with optimal bone formation at 60 kPa. Our findings show that biophysical cues can be harnessed to direct therapeutic stem-cell behaviors in situ. PMID:26366848

  3. Investigations of void formation in neutron irradiated iron and F82H steel

    DEFF Research Database (Denmark)

    Eldrup, Morten Mostgaard; Singh, Bachu Narain

    2002-01-01

    In the present work pure iron and low activation steel F82H have been neutron irradiated at temperatures in the interval 50 deg.C - 350 deg.C to a dose of 0.23 dpa (displacements per atom). The formation of defects has been investigated by the use ofpositron annihilation spectroscopy (PAS....... For irradiation temperatures of 50 deg.C and 100 deg.C also a high density of micro-voids was observed. Voids and micro-voids were also detected in lowactivation F82H steel for a low irradiation temperature (50 deg.C), while for irradiation close to the temperature of annealing stage V (250 deg.C), no voids...... below stage V by migration andcoalescence of the micro-voids and voids. The dose dependence of the electrical conductivity of iron showed a lower conductivity for the specimens irradiated at 50 deg.C than at 100 deg.C. This has been associated with the segregation of carbon at about70 deg.C where carbon...

  4. The mechanism and kinetics of void formation and growth in particulate filled PE composites

    Directory of Open Access Journals (Sweden)

    2007-11-01

    Full Text Available Volume strain measurements were carried out on PE/CaCO3 composites prepared with three different matrix polymers, containing various amounts of filler. The analysis of the debonding process and the various stages of void formation proved that the model developed for the prediction of the initiation of debonding is valid also for the studied PE/CaCO3 composites. Debonding stress is determined by the strength of interfacial adhesion, particle size and the stiffness of the matrix. In thermoplastic matrices usually two competitive processes take place: debonding and the plastic deformation of the polymer. The relative magnitude of the two processes strongly influences the number and size of the voids formed. Because of this competition and due to the wide particle size distribution of commercial fillers, only a certain fraction of the particles initiate the formation of voids. The number of voids formed is inversely proportional to the stiffness of the matrix polymer. In stiff matrices almost the entire amount of filler separates from the matrix under the effect of external load, while less than 30% debond in a PE which has an initial modulus of 0.4 GPa. Further decrease of matrix stiffness may lead to the complete absence of debonding and the composite would deform exclusively by shear yielding. Voids initiated by debonding grow during the further deformation of the composite. The size of the voids also depends on the modulus of the matrix. The rate of volume increase considerably exceeds the value predicted for cross-linked rubbers. At the same deformation and filler content the number of voids is smaller and their size is larger in soft matrices than in polymers with larger inherent modulus.

  5. Calculated Grain Size-Dependent Vacancy Supersaturation and its Effect on Void Formation

    DEFF Research Database (Denmark)

    Singh, Bachu Narain; Foreman, A. J. E.

    1974-01-01

    In order to study the effect of grain size on void formation during high-energy electron irradiations, the steady-state point defect concentration and vacancy supersaturation profiles have been calculated for three-dimensional spherical grains up to three microns in size. In the calculations...... of vacancy supersaturation as a function of grain size, the effects of internal sink density and the dislocation preference for interstitial attraction have been included. The computations show that the level of vacancy supersaturation achieved in a grain decreases with decreasing grain size. The grain size...... dependence of the maximum vacancy supersaturation in the centre of the grains is found to be very similar to the grain size dependence of the maximum void number density and void volume swelling measured in the central regions of austenitic stainless steel grains. This agreement reinforces the interpretation...

  6. DETECTION OF MOLECULAR GAS IN VOID GALAXIES: IMPLICATIONS FOR STAR FORMATION IN ISOLATED ENVIRONMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Das, M.; Honey, M. [Indian Institute of Astrophysics, Bangalore (India); Saito, T. [Department of Astronomy, Graduate school of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 133-0033 (Japan); Iono, D. [Chile Observatory, NAOJ (Japan); Ramya, S., E-mail: mousumi@iiap.res.in [Shanghai Astronomical Observatory, Shanghai (China)

    2015-12-10

    We present the detection of molecular gas from galaxies located in nearby voids using the CO(1–0) line emission as a tracer. The observations were performed using the 45 m single dish radio telescope of the Nobeyama Radio Observatory. Void galaxies lie in the most underdense parts of our universe and a significant fraction of them are gas rich, late-type spiral galaxies. Although isolated, they have ongoing star formation but appear to be slowly evolving compared to galaxies in denser environments. Not much is known about their star formation properties or cold gas content. In this study, we searched for molecular gas in five void galaxies. The galaxies were selected based on their relatively high IRAS fluxes or Hα line luminosities, both of which signify ongoing star formation. All five galaxies appear to be isolated and two lie within the Bootes void. We detected CO(1–0) emission from four of the five galaxies in our sample and their molecular gas masses lie between 10{sup 8} and 10{sup 9} M{sub ⊙}. We conducted follow-up Hα imaging observations of three detected galaxies using the Himalayan Chandra Telescope and determined their star formation rates (SFRs) from their Hα fluxes. The SFR varies from 0.2 to 1 M{sub ⊙} yr{sup −1}; which is similar to that observed in local galaxies. Our study indicates that although void galaxies reside in underdense regions, their disks contain molecular gas and have SFRs similar to galaxies in denser environments. We discuss the implications of our results.

  7. Parents Function and Behavioral Disorders in Children with and without Diurnal Voiding Dysfunction: A Comparative Study

    Directory of Open Access Journals (Sweden)

    Parsa Yousefi

    2014-09-01

    Full Text Available Background: Diurnal voiding dysfunction is one of the most common causes of pediatric urology clinic admissions. It can cause behavioral problems for children and their parents. We lunch this study to compare the parents’ function and children’s behavior problem in pediatric patients suffering from diurnal voiding dysfunction referring Arak Amir Kabir hospital. Materials and Methods: To perform this case-control study, we recruit 116 children with diurnal voiding dysfunction and compared them with other 116 children non-affected children aged between 5 to 16 years old. The child behavior checklist (CBCL4/18 for children behavior assessment and Global Assessment of Functioning (GAF for the evaluation of their parent’s behavior was completed by the parents. Data was analyzed using ANOVA, qualitative variables and χ2 formula. Results: Among 116 patient with voiding dysfunction, 10 case (8.6% showed behavioral problem while this figure was 3 case (2.6% in the control group, denoting a significant difference (p=0.04. Moreover 20 children (17.2% in the case group and 9 children (7.8% in the control group had internalizing problem (p=0.02. Twenty two children (19% with voiding dysfunction and 8 children (6.9% in the healthy group had externalizing problem which was also a significant difference (p=0.01. As a significant difference (0.01, the parent’s average stress and behavior scores in case and control group were 3.65 and 3.76, respectively. Conclusion: The higher prevalence of behavioral problem in the children suffering from diurnal voiding dysfunction and their parent’s functional impairment highlights the importance of early parent’s intervention for early treatment and subsequently prevention of future behavioral problem in their sibling.

  8. Phase-field study on geometry-dependent migration behavior of voids under temperature gradient in UO2 crystal matrix

    Science.gov (United States)

    Chen, Weijin; Peng, Yuyi; Li, Xu'an; Chen, Kelang; Ma, Jun; Wei, Lingfeng; Wang, Biao; Zheng, Yue

    2017-10-01

    In this work, a phase-field model is established to capture the void migration behavior under a temperature gradient within a crystal matrix, with an appropriate consideration of the surface diffusion mechanism and the vapor transport mechanism. The interfacial energy and the coupling between the vacancy concentration field and the crystal order parameter field are carefully modeled. Simulations are performed on UO2. The result shows that for small voids (with an area ≤ πμm2), the well-known characteristics of void migration, in consistence with the analytical model, can be recovered. The migration is manifested by a constant velocity and a minor change of the void shape. In contrast, for large voids (with an area of ˜10 μm2) initially in circular shapes, significant deformation of the void from a circular to cashew-like shape is observed. After long-time migration, the deformed void would split into smaller voids. The size-dependent behavior of void migration is due to the combined effect of the interfacial energy (which tends to keep the void in circular shape) and the surface diffusion flow (which tends to deform the void due to the nonuniform diffusion along the surface). Moreover, the initial shape of the void modifies the migration velocity and the time point when splitting occurs (for large voids) at the beginning of migration due to the shape relaxation of the void. However, it has a minor effect on the long-time migration. Our work reveals novel void migration behaviors in conditions where the surface-diffusion mechanism is dominant over the vapor transport mechanism; meanwhile, the size of the void lies at a mediate size range.

  9. Sheath structure and formation of dust voids in cylindrical plasma discharges.

    Science.gov (United States)

    Hu, Zuquan; Chen, Yinhua; Huang, Feng; Shi, Gui-fen; Zheng, Jugao; Yu, M Y

    2010-05-01

    Using a self-consistent two-dimensional fluid model the structure of the plasma sheath in a cylindrical system is investigated. The results show that there is a bumping potential in the central axis resulting in the larger outward directing ion drag force with respect to the opposite electric field force. And the process of the formation of dust voids is studied in the sheath by molecular-dynamics simulation.

  10. Nucleation and void formation mechanisms in SiC thin film growth on Si by carbonization

    Energy Technology Data Exchange (ETDEWEB)

    Li, J.P.; Steckl, A.J. [Univ. of Cincinnati, OH (United States)

    1995-02-01

    The nucleation mechanisms for SiC thin films on Si were investigated by interrupting the growth at very brief times ({approximately}1 to 10 s) using rapid thermal chemical vapor deposition in conjunction with hydrocarbon carbonization. The resulting SiC nuclei and films on Si have been studied by scanning electron microscopy and atomic force microscopy. The hydrocarbon partial pressure in the gas stream was found to determine the nucleation mode. Low precursor concentration results in initial three-dimensional (island) growth which enables the study or trench and void formation. Voids were observed to initiate when two neighboring nuclei come in contact. Trenches in the Si substrate surround each isolated nucleus, with the trench depth increasing with the diameter of the island. SiC films grown for a nominal reaction time of 1 s indicate that increasing the propane concentration results in decreases in SiC grain size and surface roughness and an increase in the nuclei density. A model is proposed for the nucleation process of SiC growth on Si by carbonization consisting of the following key steps: (1) the initial nucleation density is determined by the precursor concentration; (2) lateral and vertical growth of individual nuclei proceeds by consumption of Si atoms around their periphery, forming trenches in the substrate; (3) Si voids are formed in the Si substrate near the SiC/Si interface when nuclei grow large enough to come in contact and, thus, restrict the supply of Si atoms.

  11. Mechanism of void growth in irradiated NaCl based on exiton-induced formation of divacancies at dislocations

    Energy Technology Data Exchange (ETDEWEB)

    Dubinko, V.I. [National Science Center, Kharkov Institute of Physics and Technology, Akademicheskaya 1, 310108 Kharkov (Ukraine)]. E-mail: vdubinko@kipt.kharkov.ua; Vainshtein, D.I. [Solid State Physics Laboratory, University of Groningen, Nijenborgh 4, NL-9747 AG Groningen (Netherlands); Hartog, H.W. den [Solid State Physics Laboratory, University of Groningen, Nijenborgh 4, NL-9747 AG Groningen (Netherlands)

    2005-01-01

    We propose a mechanism of void growth in di-atomic ionic crystals due to agglomeration of divacancies produced by interactions between dislocations and excitons. An exciton can cause movement of nearby dislocation jogs, resulting in the creation of equal numbers of anion and cation vacancies (Schottky defects). Owing to the heat generated locally during the exciton annihilation, the jog can be displaced while a divacancy arises in the lattice. Subsequent diffusion and agglomeration of divacancies can result in void formation and growth. We evaluate the void nucleation and growth rates in electron irradiated NaCl.

  12. Void lattice formation in electron irradiated CaF{sub 2}: Statistical analysis of experimental data and cellular automata simulations

    Energy Technology Data Exchange (ETDEWEB)

    Zvejnieks, G., E-mail: guntars@latnet.lv; Merzlyakov, P.; Kuzovkov, V.N.; Kotomin, E.A.

    2016-02-01

    Calcium fluoride (CaF{sub 2}) is an important optical material widely used in both microlithography and deep UV windows. It is known that under certain conditions electron beam irradiation can create therein a superlattice consisting of vacancy clusters (called a void lattice). The goal of this paper is twofold. Firstly, to perform a quantitative analysis of experimental TEM images demonstrating void lattice formation, we developed two distinct image filters. As a result, we can easily calculate vacancy concentration, vacancy cluster distribution function as well as average distances between defect clusters. The results for two suggested filters are similar and demonstrate that experimental void cluster growth is accompanied by a slight increase of the void lattice constant. Secondly, we proposed a microscopic model that allows us to reproduce a macroscopic void ordering, in agreement with experimental data, and to resolve existing theoretical and experimental contradictions. Our computer simulations demonstrate that macroscopic void lattice self-organization can occur only in a narrow parameter range. Moreover, we studied the kinetics of a void lattice ordering, starting from an initial disordered stage, in a good agreement with the TEM experimental data.

  13. Formation of dislocation loops and voids in electron irradiated zinc selenide single crystals

    Science.gov (United States)

    Loginov, Y. Y.; Brown, P. D.; Kovalev, I. V.

    2017-10-01

    The formation of small dislocation loops in size of 2.5 - 45 nm and a density of 1.4·1011 cm‑2, as well as voids in size ≤10 nm in ZnS crystals were found by the transmission electron microscopy method (TEM). Samples were examined and irradiated in situ in a JEOL 4000EX-II electron microscope operated at energy of 400 keV and intensity of (1 - 4)·1019 e/cm2·s. Fine particles of a new phase in size ≤10 nm are formed also. These features can be identified from an analysis of moiré fringe contrast as phase of ZnO2. Similar defects in single crystals of ZnS formed in situ after irradiation in a transmission electron microscope JEM-100CX operated at energy of 100 keV and intensity of 3,5·1017 e/cm2·s. It was found that the formation of structural defects in ZnS under electron irradiation with above-threshold energy of defect formation (400 keV) is similar to the formation of structural defects in these crystals under electron irradiation with sub-threshold defect formation energy (100 keV).

  14. Experimental study of void formation during aluminum solidification in reduced gravity. Ph.D. Thesis - Toledo Univ.

    Science.gov (United States)

    Chiaramonte, Francis Paul, III

    1993-01-01

    Void formation due to volumetric shrinkage and liquid/vapor reorientation during aluminum solidification was observed in real time by using a radiographic viewing system in normal and reduced gravity. An end-chill directional solidification furnace with water quench was designed and constructed to solidify aluminum samples during the approximately 16 sec of reduced gravity (+/-0.02g) achieved by flying an aircraft through a parabolic trajectory. In the first series of tests the aluminum was contained in a vacuum sealed, pyrolytic boron nitride crucible. An ullage space was present during each test. Void formation was recorded for two cases: a nonwetting system, and a wetting system where wetting occurred between the aluminum and the crucible lid. The void formation in the nonwetting case was similar in normal and reduced gravity, with a single vapor cavity forming at the top of the crucible. In the wetting case during reduced gravity surface tension caused two voids to form in the top corners of the crucible, but during normal gravity only one large void formed across the top. In the second series of tests the aluminum was contained in a pyrolytic boron nitride crucible that was placed in a stainless steel container and sealed in an environment of argon plus 4 percent hydrogen. An ullage space was present during each test. Void formation was recorded for two cases: a nonwetting system, and a wetting system where wetting occurred between the aluminum and one side wall and the lid. The void for nation in the nonwetting case was similar in normal and reduced gravity, with a single vapor cavity forming at the top of the crucible, although the meniscus became more convex in reduced gravity. In the wetting case the aluminum did not climb up the corners in 1g, and one large symmetric void resulted at the top when the aluminum had solidified. In the wetting case during reduced gravity the molten aluminum was drawn up the wetted wall and partially across the lid by a

  15. Kirkendall void formation in reverse step graded Si1‑xGex/Ge/Si(001) virtual substrates

    Science.gov (United States)

    Sivadasan, Vineet; Rhead, Stephen; Leadley, David; Myronov, Maksym

    2018-02-01

    Formation of Kirkendall voids is demonstrated in the Ge underlayer of reverse step graded Si1‑xGex/Ge buffer layers grown on Si(001) using reduced pressure chemical vapour deposition (RP-CVD). This phenomenon is seen when the constant composition Si1‑xGex layer is grown at high temperatures and for x ≤ 0.7. The density and size of the spherical voids can be tuned by changing Ge content in the Si1‑xGex and other growth parameters.

  16. Influence of void defects on partial discharge behavior of superconducting busbar insulation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chunyu; Huang, Xiongyi, E-mail: huangxy@ipp.ac.cn; Lu, Kun; Li, Guoliang; Zhu, Haisheng; Wang, Jun; Wang, Cao; Dai, Zhiheng; Fang, Linlin; Song, Yuntao

    2017-06-15

    Highlights: • PD detection method was used to check the quality of the superconducting busbar insulation. • The samples with different void fraction were manufactured for comparing. • The discharge inception voltage, PRPD pattern was tested and studied for the samples with different void content. • The PD behaviors in oil bath and air condition were compared. - Abstract: For a magnetic confinement fusion device, the superconducting magnets and busbars need to be insulated with one layer of solid insulation to isolate the high voltage potential from the ground. The insulation layer commonly consists of several interleaved layers of epoxy resin-impregnated glass fiber tapes and polyimide films. The traditional electrical inspection methods for such solidified insulation on the magnet and busbar are a DC voltage test or a Paschen test. These tests measure the quality of the insulation based on the value of leakage currents. However, even if there is a larger quantity of high dielectric strength material implemented, if there are some microcavities or delaminations in the insulation system, the leakage current may be limited to microampere levels under testing levels over dozens of kilovolts. Therefore, it is difficult to judge the insulation quality just by the magnitudes of leakage current. Under long-term operation, such imperceptible defects will worsen and finally completely break down the insulation because of partial discharge (PD) incidents. Therefore, a PD detection test is an important complement to the DC voltage and Paschen tests for magnet and busbar insulations in the field of fusion. It is known that the PD detection test is a mature technique in the electric power industry. In this paper, the PD characteristics of samples containing glass fiber-reinforced composite insulations for use with the superconducting busbar were presented and discussed. Various samples with different void contents were prepared and the PD behaviors were tested.

  17. Home uroflowmetry biofeedback in behavioral training for dysfunctional voiding in school-age children: a randomized controlled study

    NARCIS (Netherlands)

    Klijn, Aart J.; Uiterwaal, Cuno S. P. M.; Vijverberg, Marianne A. W.; Winkler, Pauline L. H.; Dik, Pieter; de Jong, Tom P. V. M.

    2006-01-01

    We studied the added value of home uroflowmetry for biofeedback training compared to added attention and standard therapy in a multicomponent behavioral training program for voiding disorders in school-age children. Little is known about the role of biofeedback by home uroflowmetry for dysfunctional

  18. Void formation in pure aluminium irradiated with high-energetic electron beams and gamma-quanta

    DEFF Research Database (Denmark)

    Gan, V. V.; Ozhigou, L. S.; Yamnitsky, V. A.

    1983-01-01

    The spatial distribution of displaced atoms and helium atoms and also the spectra of damaging energies of primary displaced atoms in a thick aluminium target irradiated with electrons of 225 MeV energy were calculated. Pure aluminium (99.9999%) irradiated up to 0.04 dose was studied by electron-m......-microscopy. Voids of size 5 to 40 nm were obtained and their vacancy nature was estimated. The dislocation structure of the material was studied...

  19. Colloids in inhomogeneous external magnetic fields: particle tweezing, trapping and void formation

    Science.gov (United States)

    Froltsov, V. A.; Likos, C. N.; Löwen, H.

    2004-09-01

    Two-dimensional super-paramagnetic suspensions that are confined to a planar liquid-gas interface and exposed to an inhomogeneous external magnetic field directed perpendicular to the interface are studied by extensive Monte Carlo computer simulations. The external field is a superposition of a homogeneous field and a localized inhomogeneity, modelled by a Gaussian function. The inhomogeneity causes two combined effects that compete against each other: it provides an external potential, modifying at the same time the mutual interparticle repulsion. If the inhomogeneity enhances the strength of the homogeneous profile, the inhomogeneous field is a 'magnetic tweezer' for low particle densities. At higher densities, on the other hand, there is a small accumulation in the centre of the inhomogeneous field, which leads to a depletion zone outside the inhomogeneity due to the mutual interparticle repulsion. Very large inhomogeneities produce local crystallites surrounded by a depletion ring. If the inhomogeneity reduces the total field strength, particles are repelled from the inhomogeneity and voids are generated in the suspension. Our predictions are of relevance to the direct transport of magnetic particles and can be verified in real-space experiments of super-paramagnetic suspensions.

  20. Voiding dysfunction - A review

    Directory of Open Access Journals (Sweden)

    Sripathi V

    2005-01-01

    Full Text Available In a child who is toilet trained the sudden onset of daytime wetting with frequency or urgency is alarming to the parents. Initially this subject was subdivided into a number of descriptive clinical conditions which led to a lot of confusion in recognition and management. Subsequently, the term elimination dysfunction was coined by Stephen Koff to emphasise the association between recurrent urinary infection, wetting, constipation and bladder overactivity. From a urodynamic point of view, in voiding dysfunction, there is either detrusor overactivity during bladder filling or dyssynergic action between the detrusor and the external sphincter during voiding. Identifying a given condition as a ′filling phase dysfunction′ or ′voiding phase dysfunction′ helps to provide appropriate therapy. Objective clinical criteria should be used to define voiding dysfunction. These include bladder wall thickening, large capacity bladder and infrequent voiding, bladder trabeculation and spinning top deformity of the urethra and a clinically demonstrated Vincent′s curtsy. The recognition and treatment of constipation is central to the adequate treatment of voiding dysfunction. Transcutaneous electric nerve stimuation for the treatment of detrusor overactivity, biofeedback with uroflow EMG to correct dyssynergic voiding, and behavioral therapy all serve to correct voiding dysfunction in its early stages. In established neurogenic bladder disease the use of Botulinum Toxin A injections into the detrusor or the external sphincter may help in restoring continence especially in those refractory to drug therapy. However in those children in whom the upper tracts are threatened, augmentation of the bladder may still be needed.

  1. Investigations on Void Formation in Composite Molding Processes and Structural Damping in Fiber-Reinforced Composites with Nanoscale Reinforcements

    Science.gov (United States)

    DeValve, Caleb Joshua

    Fiber-reinforced composites (FRCs) offer a stronger and lighter weight alternative to traditional materials used in engineering components such as wind turbine blades and rotorcraft structures. Composites for these applications are often fabricated using liquid molding techniques, such as injection molding or resin transfer molding. One significant issue during these processing methods is void formation due to incomplete wet-out of the resin within the fiber preform, resulting in discontinuous material properties and localized failure zones in the material. A fundamental understanding of the resin evolution during processing is essential to designing processing conditions for void-free filling, which is the first objective of the dissertation. Secondly, FRCs used in rotorcraft experience severe vibrational loads during service, and improved damping characteristics of the composite structure are desirable. To this end, a second goal is to explore the use of matrix-embedded nanoscale reinforcements to augment the inherent damping capabilities in FRCs. The first objective is addressed through a computational modeling and simulation of the infiltrating dual-scale resin flow through the micro-architectures of woven fibrous preforms, accounting for the capillary effects within the fiber bundles. An analytical model is developed for the longitudinal permeability of flow through fibrous bundles and applied to simulations which provide detailed predictions of local air entrapment locations as the resin permeates the preform. Generalized design plots are presented for predicting the void content and processing time in terms of the Capillary and Reynolds Numbers governing the molding process. The second portion of the research investigates the damping enhancement provided to FRCs in static and rotational configurations by different types and weight fractions of matrix-embedded carbon nanotubes (CNTs) in high fiber volume fraction composites. The damping is measured using

  2. Effect of Grain Size on Void Formation during High-Energy Electron Irradiation of Austenitic Stainless Steel

    DEFF Research Database (Denmark)

    Singh, Bachu Narain

    1974-01-01

    ’ model based on the property of grain boundaries as neutral and unsaturable sinks for vacancies and self-interstitials. It is suggested that even in the presence of sufficiently large amount of impurity gas atoms, a critical level of vacancy supersaturation is necessary to produce critically sized......Thin foils of an ‘ experimental ’ austenitic stainless steel, with and without dispersions of aluminium oxide particles, are irradiated with 1 MeV electrons in a High Voltage Electron Microscope at 600°C. Evidence of grain size dependent void nucleation, void concentration, and void volume swelling...... are presented for grains in the size range 0°45 to 50 μ. In both undoped and helium-doped samples the void nucleation is delayed, void concentration is lowered, and void volume swelling is reduced by decreasing the size of the grain under irradiation. The results are discussed in terms of a ‘ defect depletion...

  3. Comparison of voiding function and nociceptive behavior in two rat models of cystitis induced by cyclophosphamide or acetone

    Science.gov (United States)

    Saitoh, Chikashi; Yokoyama, Hitoshi; Chancellor, Michael B.; de Groat, William C.; Yoshimura, Naoki

    2009-01-01

    Aims Nociceptive behavior and its relationship with bladder dysfunction were investigated in two cystitis models, which were induced by intraperitoneal (ip) injection of cyclophosphamide (CYP) or intravesical instillation of acetone, using freely moving, non-catheterized conscious rats. Methods Female Sprague-Dawley rats were used. Cystitis was induced by ip injection of CYP (100 and 200mg/kg) or intravesical instillation of acetone (10, 30 and 50%) via a polyethylene catheter temporarily inserted into the bladder through the urethra. Then the incidence of nociceptive behavior (immobility with decreased breathing rates) was scored. Voided urine was collected simultaneously and continuously to measure bladder capacity. The plasma extravasation in the bladder was quantified by an evans blue (EB) dye leakage technique. Results CYP (100mg/kg, ip) induced nociceptive behavior without affecting bladder capacity or EB concentration in the bladder. A higher dose of CYP (200mg/kg, ip) decreased bladder capacity and increased EB levels as well as nociceptive behavior. In contrast, intravesical instillation of acetone (30%) decreased bladder capacity and increased EB levels, but evoked nociceptive behavior less frequently compared with CYP-treated animals. In capsaicin pretreated rats, nociceptive behavior induced by CYP or acetone was reduced; however, the overall effects of CYP or acetone on bladder capacity and bladder EB levels were unaffected. Conclusions These results suggest that there is a difference in the induction process of nociceptive behavior and small bladder capacity after two different types of bladder irritation and that C-fiber sensitization is more directly involved in pain sensation than reduced bladder capacity. PMID:19618450

  4. The Effect Of Void Formation On The Reliability Of ED-XRF Measurements In Lead-Free Reflow Soldering

    Directory of Open Access Journals (Sweden)

    Koncz-Horváth D.

    2015-06-01

    Full Text Available In lead-free reflow soldering, the presence of voids should be taken into account. For this reason, the effect of the applied heating profiles was examined via the characterization of voids in galvanic and immersion Sn coatings. According to EU Directive 2002/95/EC, the screening of Pb element of reflow soldering (i.e. of electrical and electronic equipment is necessary; and the practical implementation of this measurement is largely affected by the characteristics of the solder (i.e. the presence of voids and the inhomogeneity of the solder. Comparing the results of the above two coating methods, it was found that by chemical coating more voids were formed and the detected lead content was higher than for galvanic Sn. The standard deviation of Ag and Cu concentrations was mainly influenced by the appearance of large compounds in the second case, while with chemical coating, no large compounds were formed due to the elevated number of voids.

  5. The Temperature Dependence of Void and Bubble Formation and Growth in Aluminium during 600 MeV Proton Irradiation

    DEFF Research Database (Denmark)

    Victoria, M.; Green, W.V; Singh, Bachu Narain

    1984-01-01

    different temperatures in the range from 130°–430°C, to displacement doses of up to 5 dpa and helium contents of over 1000 appm. The TEM examinations have shown that at all irradiation temperatures and displacement doses, helium bubbles are formed uniformly through the whole grain interior. No voids...

  6. Prompted voiding treatment of urinary incontinence in nursing home patients. A behavior management approach for nursing home staff.

    Science.gov (United States)

    Schnelle, J F; Traughber, B; Sowell, V A; Newman, D R; Petrilli, C O; Ory, M

    1989-11-01

    This study evaluated a treatment procedure in which 126 incontinent nursing home patients were checked on an hourly basis, asked if they needed toileting assistance (prompted), and socially reinforced for appropriate toileting. Urodynamic analysis (including cystometrogram), provocative stress test, and behavioral assessment revealed that the nursing home patients were severely debilitated, with 65% demonstrating bladder abnormalities, 87% incapable of independent toileting, and 25% failing to score on the Mini-Mental Status Exam (average score, 8.0). The treatment procedures were evaluated with a multiple baseline design in which subjects were randomly divided into immediate or delayed treatment groups after a baseline observation period. During treatment, the frequency of incontinence per 12 hours changed from a baseline average of 3.85 to a treatment average of 1.91. Three behavioral measures that can be easily collected by nursing staff significantly predicted continence levels during treatment (multiple R, 0.79) and change in incontinence during treatment (multiple R, 0.64). These prognostic criteria offer nursing staff a cost-effective method for selecting the most responsive patients for prompted-voiding treatment.

  7. Air void structure and frost resistance

    DEFF Research Database (Denmark)

    Hasholt, Marianne Tange

    2014-01-01

    are conducted. Results were not originally presented in a way, which made comparison possible. Here the amount of scaled material is depicted as function of air voids parameters: total air content, specific surface, spacing factor, and total surface area of air voids. The total surface area of air voids...... is proportional to the product of total air content and specific surface. In all 4 cases, the conclusion is concurrent that the parameter of total surface area of air voids performs equally well or better than the spacing factor when linking air void characteristics to frost resistance (salt frost scaling...... will take place in the air void, being feed from the capillary, but without pressure build-up in the capillary. If the capillary is not connected to an air void, ice formation will take place in the capillary pore, where it can generate substantial pressure. Like this, frost resistance depends...

  8. Partial discharges in spheroidal voids: Void orientation

    DEFF Research Database (Denmark)

    McAllister, Iain Wilson

    1997-01-01

    Partial discharge transients can be described in terms of the charge induced on the detecting electrode. The influence of the void parameters upon the induced charge is examined and discussed for spheroidal voids. It is shown that a quantitative interpretation of the induced charge requires...

  9. The Cosmically Depressed: Life, Sociology and Identity of Voids

    Science.gov (United States)

    van de Weygaert, R.; Platen, E.; Tigrak, E.; Hidding, J.; van der Hulst, J. M.; Aragón-Calvo, M. A.; Stanonik, K.; van Gorkom, J. H.

    2010-10-01

    In this contribution we review and discuss several aspects of Cosmic Voids, as a background for our void galaxy project (accompanying paper by Stanonik et al.). Voids are a major component of the large scale distribution of matter and galaxies in the Universe. Following a sketch of the general characteristics of void formation and evolution, we describe the influence of the environment on their development and structure and the characteristic hierarchical buildup of the cosmic void population. In order to be able to study the resulting tenuous void substructure and the galaxies populating the interior of voids, we subsequently set out to describe our parameter free tessellation-based watershed void finding technique. It allows us to trace the outline, shape and size of voids in galaxy redshift surveys. The application of this technique enables us to find galaxies in the deepest troughs of the cosmic galaxy distribution, and has formed the basis of our void galaxy program.

  10. The Development of Voiding

    DEFF Research Database (Denmark)

    Olsen, Lars Henning

    2011-01-01

    The thesis addresses some new aspeccts in the development of voiding function from midgestation into early childhood.......The thesis addresses some new aspeccts in the development of voiding function from midgestation into early childhood....

  11. Pediatric Voiding Cystourethrogram

    Science.gov (United States)

    Scan for mobile link. Children's (Pediatric) Voiding Cystourethrogram A children’s (pediatric) voiding cystourethrogram uses fluoroscopy – a form of real-time x-ray – to examine a child’s bladder ...

  12. Assembly of filamentary void galaxy configurations

    NARCIS (Netherlands)

    Rieder, Steven; van de Weijgaert, Rien; Cautun, Marius; Beygu, Burcu; Zwart, Simon Portegies

    2013-01-01

    We study the formation and evolution of filamentary configurations of dark matter haloes in voids. Our investigation uses the high-resolution Lambda cold dark matter simulation CosmoGrid to look for void systems resembling the VGS_31 elongated system of three interacting galaxies that was recently

  13. One-pot formation of SnO2 hollow nanospheres and α-Fe2O3@SnO2 nanorattles with large void space and their lithium storage properties

    KAUST Repository

    Chen, Jun Song

    2009-01-01

    In this work, uniform SnO2 hollow nanospheres with large void space have been synthesized by a modified facile method. The void space can be easily controlled by varying the reaction time. The formation of interior void space is based on an inside-out Ostwald ripening mechanism. More importantly, this facile one-pot process can be extended to fabricate rattle-type hollow structures using α-Fe2O3@SnO2 as an example. Furthermore, the electrochemical lithium storage properties have been investigated. It is found that α-Fe2O3@SnO 2 nanorattles manifest a much lower initial irreversible loss and higher reversible capacity compared to SnO2 hollow spheres. This interesting finding supports a general hypothesis that a synergistic effect between functional core and shell materials can lead to improved lithium storage capabilities. © The Royal Society of Chemistry 2009.

  14. Chaotic behavior in bubble formation dynamics

    Science.gov (United States)

    Tufaile, A.; Sartorelli, J. C.

    2000-01-01

    We constructed an experimental apparatus to study the dynamics of the formation of air bubbles in a submerged nozzle in a water/glycerin solution inside a cylindrical tube. The delay time between successive bubbles was measured with a laser-photodiode system. It was observed bifurcations, chaotic behavior, and sudden changes in a periodic regime as a function of the decreasing air pressure in a reservoir. We also observed dynamical effects by applying a sound wave tuned to the fundamental frequency of the air column above the solution. As a function of the sound wave amplitude, we obtained a limit cycle, a flip bifurcation, chaotic behavior, and the synchronization of the bubbling with sound wave frequency. We related some of the different dynamical behaviors to coalescent effects and bubble sizes.

  15. Effect of void cluster on ductile failure evolution

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    2016-01-01

    The behavior of a non-uniform void distribution in a ductile material is investigated by using a cell model analysis to study a material with a periodic pattern of void clusters. The special clusters considered consist of a number of uniformly spaced voids located along a plane perpendicular...

  16. Generation of Subsurface Voids, Incubation Effect, and Formation of Nanoparticles in Short Pulse Laser Interactions with Bulk Metal Targets in Liquid: Molecular Dynamics Study

    Science.gov (United States)

    2017-01-01

    The ability of short pulse laser ablation in liquids to produce clean colloidal nanoparticles and unusual surface morphology has been employed in a broad range of practical applications. In this paper, we report the results of large-scale molecular dynamics simulations aimed at revealing the key processes that control the surface morphology and nanoparticle size distributions by pulsed laser ablation in liquids. The simulations of bulk Ag targets irradiated in water are performed with an advanced computational model combining a coarse-grained representation of liquid environment and an atomistic description of laser interaction with metal targets. For the irradiation conditions that correspond to the spallation regime in vacuum, the simulations predict that the water environment can prevent the complete separation of the spalled layer from the target, leading to the formation of large subsurface voids stabilized by rapid cooling and solidification. The subsequent irradiation of the laser-modified surface is found to result in a more efficient ablation and nanoparticle generation, thus suggesting the possibility of the incubation effect in multipulse laser ablation in liquids. The simulations performed at higher laser fluences that correspond to the phase explosion regime in vacuum reveal the accumulation of the ablation plume at the interface with the water environment and the formation of a hot metal layer. The water in contact with the metal layer is brought to the supercritical state and provides an environment suitable for nucleation and growth of small metal nanoparticles from metal atoms emitted from the hot metal layer. The metal layer itself has limited stability and can readily disintegrate into large (tens of nanometers) nanoparticles. The layer disintegration is facilitated by the Rayleigh–Taylor instability of the interface between the higher density metal layer decelerated by the pressure from the lighter supercritical water. The nanoparticles

  17. Generation of Subsurface Voids, Incubation Effect, and Formation of Nanoparticles in Short Pulse Laser Interactions with Bulk Metal Targets in Liquid: Molecular Dynamics Study.

    Science.gov (United States)

    Shih, Cheng-Yu; Shugaev, Maxim V; Wu, Chengping; Zhigilei, Leonid V

    2017-08-03

    The ability of short pulse laser ablation in liquids to produce clean colloidal nanoparticles and unusual surface morphology has been employed in a broad range of practical applications. In this paper, we report the results of large-scale molecular dynamics simulations aimed at revealing the key processes that control the surface morphology and nanoparticle size distributions by pulsed laser ablation in liquids. The simulations of bulk Ag targets irradiated in water are performed with an advanced computational model combining a coarse-grained representation of liquid environment and an atomistic description of laser interaction with metal targets. For the irradiation conditions that correspond to the spallation regime in vacuum, the simulations predict that the water environment can prevent the complete separation of the spalled layer from the target, leading to the formation of large subsurface voids stabilized by rapid cooling and solidification. The subsequent irradiation of the laser-modified surface is found to result in a more efficient ablation and nanoparticle generation, thus suggesting the possibility of the incubation effect in multipulse laser ablation in liquids. The simulations performed at higher laser fluences that correspond to the phase explosion regime in vacuum reveal the accumulation of the ablation plume at the interface with the water environment and the formation of a hot metal layer. The water in contact with the metal layer is brought to the supercritical state and provides an environment suitable for nucleation and growth of small metal nanoparticles from metal atoms emitted from the hot metal layer. The metal layer itself has limited stability and can readily disintegrate into large (tens of nanometers) nanoparticles. The layer disintegration is facilitated by the Rayleigh-Taylor instability of the interface between the higher density metal layer decelerated by the pressure from the lighter supercritical water. The nanoparticles emerging

  18. The sparkling Universe: clustering of voids and void clumps

    Science.gov (United States)

    Lares, Marcelo; Ruiz, Andrés N.; Luparello, Heliana E.; Ceccarelli, Laura; Garcia Lambas, Diego; Paz, Dante J.

    2017-07-01

    We analyse the clustering of cosmic voids using a numerical simulation and the main galaxy sample from the Sloan Digital Sky Survey. We take into account the classification of voids into two types that resemble different evolutionary modes: those with a rising integrated density profile (void-in-void mode or R-type) and voids with shells (void-in-cloud mode or S-type). The results show that voids of the same type have stronger clustering than the full sample. We use the correlation analysis to define void clumps, associations with at least two voids separated by a distance of at most the mean void separation. In order to study the spatial configuration of void clumps, we compute the minimal spanning tree and analyse their multiplicity, maximum length and elongation parameter. We further study the dynamics of the smaller sphere that enclose all the voids in each clump. Although the global densities of void clumps are different according to their member-void types, the bulk motions of these spheres are remarkably lower than those of randomly placed spheres with the same radius distribution. In addition, the coherence of pairwise void motions does not strongly depend on whether voids belong to the same clump. Void clumps are useful to analyse the large-scale flows around voids, since voids embedded in large underdense regions are mostly in the void-in-void regime, where the expansion of the larger region produces the separation of voids. Similarly, voids around overdense regions form clumps that are in collapse, as reflected in the relative velocities of voids that are mostly approaching.

  19. VIDE: The Void IDentification and Examination toolkit

    Science.gov (United States)

    Sutter, P. M.; Lavaux, G.; Hamaus, N.; Pisani, A.; Wandelt, B. D.; Warren, M.; Villaescusa-Navarro, F.; Zivick, P.; Mao, Q.; Thompson, B. B.

    2015-03-01

    We present VIDE, the Void IDentification and Examination toolkit, an open-source Python/C++ code for finding cosmic voids in galaxy redshift surveys and N -body simulations, characterizing their properties, and providing a platform for more detailed analysis. At its core, VIDE uses a substantially enhanced version of ZOBOV (Neyinck 2008) to calculate a Voronoi tessellation for estimating the density field and performing a watershed transform to construct voids. Additionally, VIDE provides significant functionality for both pre- and post-processing: for example, VIDE can work with volume- or magnitude-limited galaxy samples with arbitrary survey geometries, or dark matter particles or halo catalogs in a variety of common formats. It can also randomly subsample inputs and includes a Halo Occupation Distribution model for constructing mock galaxy populations. VIDE uses the watershed levels to place voids in a hierarchical tree, outputs a summary of void properties in plain ASCII, and provides a Python API to perform many analysis tasks, such as loading and manipulating void catalogs and particle members, filtering, plotting, computing clustering statistics, stacking, comparing catalogs, and fitting density profiles. While centered around ZOBOV, the toolkit is designed to be as modular as possible and accommodate other void finders. VIDE has been in development for several years and has already been used to produce a wealth of results, which we summarize in this work to highlight the capabilities of the toolkit. VIDE is publicly available at

  20. Shock Compression of Solid with Voids by Gridless Lagrangian SPH

    Science.gov (United States)

    Tanaka, Katsumi

    2006-07-01

    The mechanism of formation of local hot spots with a single or multiple voids has been studied numerically by Smoothed Particle Hydrodynamics (SPH). Temperature increase was not enough to initiate emulsion explosives for incident shock pressure lower than 10GPa in the case of single void. It is important for formation of local hot spot to consider complex physical interaction and chemistry in multiple voids.

  1. Air void clustering.

    Science.gov (United States)

    2015-06-01

    Air void clustering around coarse aggregate in concrete has been identified as a potential source of : low strengths in concrete mixes by several Departments of Transportation around the country. Research was : carried out to (1) develop a quantitati...

  2. Diffusion plus explosion mechanism of void-crack transition in irradiated NaCl

    Science.gov (United States)

    Dubinko, V. I.; Turkin, A. A.; Vainshtein, D. I.; Hartog, H. W. Den

    Experimental and theoretical results are presented on the formation of large vacancy voids and cracks in NaCl under irradiation. The crack length increases gradually with increasing stored energy, which is explained by a new mechanism of diffusion accumulation and explosive release of energy in voids and cracks. It is shown that the colloid number density, which determines the critical void radius that triggers the explosion process, has a drastic effect on the ultimate mechanical stability of material. If it is low as in NaCl doped with Br then the critical void radius is large and difficult to reach. If it is high as in NaCl:KBF4 it takes a high colloid volume fraction to initiate the void-crack transition, which progresses rather slowly. The materials doped with Ba or K, and natural rock salts show the transitional behavior, which is characterized by an early start and a rapid progress of the void-crack transition, resulting in a subsequent fracture of the material.

  3. Cause Analysis on the Void under Slabs of Cement Concrete Pavement

    Science.gov (United States)

    Wen, Li; Zhu, Guo Xin; Baozhu

    2017-06-01

    This paper made a systematic analysis on the influence of the construction, environment, water and loads on the void beneath road slabs, and also introduced the formation process of structural void and pumping void, and summarizes the deep reasons for the bottom of the cement concrete pavement. Based on the analysis above, this paper has found out the evolution law of the void under slabs which claimed that the void usually appeared in the slab corners and then the cross joint, resulting void in the four sides with the void area under the front slab larger than the rear one.

  4. Dislocation and void segregation in copper during neutron irradiation

    DEFF Research Database (Denmark)

    Singh, Bachu Narain; Leffers, Torben; Horsewell, Andy

    1986-01-01

    ); the irradiation experiments were carried out at 250 degree C. The irradiated specimens were examined by transmission electron microscopy. At both doses, the irradiation-induced structure was found to be highly segregated; the dislocation loops and segments were present in the form of irregular walls and the voids...... density, the void swelling rate was very high (approximately 2. 5% per dpa). The implications of the segregated distribution of sinks for void formation and growth are briefly discussed....

  5. Effects of Voids on Concrete Tensile Fracturing: A Mesoscale Study

    Directory of Open Access Journals (Sweden)

    Lei Xu

    2017-01-01

    Full Text Available A two-dimensional mesoscale modeling framework, which considers concrete as a four-phase material including voids, is developed for studying the effects of voids on concrete tensile fracturing under the plane stress condition. Aggregate is assumed to behave elastically, while a continuum damaged plasticity model is employed to describe the mechanical behaviors of mortar and ITZ. The effects of voids on the fracture mechanism of concrete under uniaxial tension are first detailed, followed by an extensive investigation of the effects of void volume fraction on concrete tensile fracturing. It is found that both the prepeak and postpeak mesoscale cracking in concrete are highly affected by voids, and there is not a straightforward relation between void volume fraction and the postpeak behavior due to the randomness of void distribution. The fracture pattern of concrete specimen with voids is controlled by both the aggregate arrangement and the distribution of voids, and two types of failure modes are identified for concrete specimens under uniaxial tension. It is suggested that voids should be explicitly modeled for the accurate fracturing simulation of concrete on the mesoscale.

  6. An Interacting Galaxy System along a Filament in a Void

    NARCIS (Netherlands)

    Beygu, B.; Kreckel, K.; van de Weijgaert, R.; van der Hulst, J. M.; van Gorkom, J. H.

    Cosmological voids provide a unique environment for the study of galaxy formation and evolution. The galaxy population in their interiors has properties significantly different from average field galaxies. As part of our Void Galaxy Survey (VGS), we have found a system of three interacting galaxies

  7. Void shape effects and voids starting from cracked inclusion

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    2011-01-01

    to 10−10, which means that the metal undergoes huge strains before coalescence. This is accounted for in the present analyses by using remeshing techniques. The evolution of the void shape during the large deformations is a natural outcome of the numerical analysis. Also the effect of different initial...... second phase particle. As the particle deforms relatively little the void growth is here dominated by strong blunting of the metal at the tip of the initial penny-shaped crack. These analyses are used to estimate how well the void shape evolution would be approximated by assuming that the presence...... void shapes is considered, as well as the effect of different spacings between the voids in the axial and transverse directions. While these first analyses are carried out for voids in a homogeneous metal, a second set of cell model studies are carried out for voids that initiate from a crack in a hard...

  8. Morphological Segregation in the Surroundings of Cosmic Voids

    Energy Technology Data Exchange (ETDEWEB)

    Ricciardelli, Elena; Tamone, Amelie [Laboratoire d’Astrophysique, École Polytechnique Fédérale de Lausanne (EPFL), 1290 Sauverny (Switzerland); Cava, Antonio [Observatoire de Genève, Université de Genève, 51 Ch. des Maillettes, 1290 Versoix (Switzerland); Varela, Jesus, E-mail: elena.ricciardelli@epfl.ch [Centro de Estudios de Física del Cosmos de Aragón (CEFCA), Plaza San Juan 1, E-44001 Teruel (Spain)

    2017-09-01

    We explore the morphology of galaxies living in the proximity of cosmic voids, using a sample of voids identified in the Sloan Digital Sky Survey Data Release 7. At all stellar masses, void galaxies exhibit morphologies of a later type than galaxies in a control sample, which represent galaxies in an average density environment. We interpret this trend as a pure environmental effect, independent of the mass bias, due to a slower galaxy build-up in the rarefied regions of voids. We confirm previous findings about a clear segregation in galaxy morphology, with galaxies of a later type being found at smaller void-centric distances with respect to the early-type galaxies. We also show, for the first time, that the radius of the void has an impact on the evolutionary history of the galaxies that live within it or in its surroundings. In fact, an enhanced fraction of late-type galaxies is found in the proximity of voids larger than the median void radius. Likewise, an excess of early-type galaxies is observed within or around voids of a smaller size. A significant difference in galaxy properties in voids of different sizes is observed up to 2 R {sub void}, which we define as the region of influence of voids. The significance of this difference is greater than 3 σ for all the volume-complete samples considered here. The fraction of star-forming galaxies shows the same behavior as the late-type galaxies, but no significant difference in stellar mass is observed in the proximity of voids of different sizes.

  9. Morphological Segregation in the Surroundings of Cosmic Voids

    Science.gov (United States)

    Ricciardelli, Elena; Cava, Antonio; Varela, Jesus; Tamone, Amelie

    2017-09-01

    We explore the morphology of galaxies living in the proximity of cosmic voids, using a sample of voids identified in the Sloan Digital Sky Survey Data Release 7. At all stellar masses, void galaxies exhibit morphologies of a later type than galaxies in a control sample, which represent galaxies in an average density environment. We interpret this trend as a pure environmental effect, independent of the mass bias, due to a slower galaxy build-up in the rarefied regions of voids. We confirm previous findings about a clear segregation in galaxy morphology, with galaxies of a later type being found at smaller void-centric distances with respect to the early-type galaxies. We also show, for the first time, that the radius of the void has an impact on the evolutionary history of the galaxies that live within it or in its surroundings. In fact, an enhanced fraction of late-type galaxies is found in the proximity of voids larger than the median void radius. Likewise, an excess of early-type galaxies is observed within or around voids of a smaller size. A significant difference in galaxy properties in voids of different sizes is observed up to 2 R void, which we define as the region of influence of voids. The significance of this difference is greater than 3σ for all the volume-complete samples considered here. The fraction of star-forming galaxies shows the same behavior as the late-type galaxies, but no significant difference in stellar mass is observed in the proximity of voids of different sizes.

  10. Archaeology of Void Spaces

    Science.gov (United States)

    Look, Cory

    The overall goal of this research is to evaluate the efficacy of pXRF for the identification of ancient activity areas at Pre-Columbian sites in Antigua that range across time periods, geographic regions, site types with a variety of features, and various states of preservation. These findings have important implications for identifying and reconstructing places full of human activity but void of material remains. A synthesis for an archaeology of void spaces requires the construction of new ways of testing anthrosols, and identifying elemental patterns that can be used to connect people with their places and objects. This research begins with an exploration of rich middens in order to study void spaces. Midden archaeology has been a central focus in Caribbean research, and consists of an accumulation of discarded remnants from past human activities that can be tested against anthrosols. The archaeological collections visited for this research project involved creating new databases to generate a comprehensive inventory of sites, materials excavated, and assemblages available for study. Of the more than 129 Pre-Columbian sites documented in Antigua, few sites have been thoroughly surveyed or excavated. Twelve Pre-Columbian sites, consisting of thirty-six excavated units were selected for study; all of which contained complete assemblages for comparison and soil samples for testing. These excavations consisted almost entirely of midden excavations, requiring new archaeological investigations to be carried out in spaces primarily void of material remains but within the village context. Over the course of three seasons excavations, shovel test pits, and soil augers were used to obtain a variety of anthrosols and archaeological assemblages in order to generate new datasets to study Pre-Columbian activity areas. The selection of two primary case study sites were used for comparison: Indian Creek and Doigs. Findings from this research indicate that accounting for the

  11. Diffusion in and around alginate and chitosan films with embedded sub-millimeter voids

    Energy Technology Data Exchange (ETDEWEB)

    Patra, Subhajit; Bal, Dharmendra Kumar; Ganguly, Somenath, E-mail: snganguly@che.iitkgp.ernet.in

    2016-02-01

    Hydrogel scaffolds from biopolymers have potential use in the controlled release of drugs, and as 3-D structure for the formation of tissue matrix. This article describes the solute release behavior of alginate and chitosan films with embedded voids of sub-millimeter dimensions. Nitrogen gas was bubbled in a fluidic arrangement to generate bubbles, prior to the crosslinking. The crosslinked gel was dried in a vacuum oven, and subsequently, soaked in Vitamin B-12 solution. The dimensions of the voids immediately after the cross-linking of gel, and also after complete drying were obtained using a digital microscope and scanning electron microscope respectively. The porosity of the gel was measured gravimetrically. The release of Vitamin B-12 in PBS buffer on a shaker was studied. The release experiments were repeated at an elevated temperature of 37 °C in the presence of lysozyme. The diffusion coefficient within the gel layer and the mass transfer coefficient at the interface with the bulk-liquid were estimated using a mathematical model. For comparison, the experiment was repeated with a film that does not have any embedded void. The enhancement in diffusion coefficient due to the presence of voids is discussed in this article. - Highlights: • Formation of sub-millimeter voids in biopolymer films using fluidic arrangement • The retention of self-assembled bubbles in films after crosslinking, and drying • The enhancement observed in release of model drug with introduction of voids • The diffusion coefficients in and around biopolymer films from model regression • Use of classical model in explaining release profiles from dual porosity media.

  12. Adolescent Work Experiences and Family Formation Behavior

    Science.gov (United States)

    Staff, Jeremy; VanEseltine, Matthew; Woolnough, April; Silver, Eric; Burrington, Lori

    2012-01-01

    A long-standing critique of adolescent employment is that it engenders a precocious maturity of more adult-like roles and behaviors, including school disengagement, substance use, sexual activity, inadequate sleep and exercise, and work-related stress. Though negative effects of high-intensity work on adolescent adjustment have been found, little…

  13. Interaction of very small voids with larger voids

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    1998-01-01

    For a very small void in the material between much larger voids the influence of local stress increases induced by the larger voids is studied numerically. The point of interest is whether or not such local stress increases result in a cavitation instability at the tiny void, even if the average ...... an important role. (C) 1998 Elsevier Science Ltd. All rights reserved....... the full 3D numerical problem. For overall stress levels as large as those reached ahead of a blunting crack tip, a cavitation instability at the small void, induced by interaction with the large voids, is not found here. But the results show that localization of plastic how in the unit cell plays...

  14. CTF Void Drift Validation Study

    Energy Technology Data Exchange (ETDEWEB)

    Salko, Robert K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gosdin, Chris [Pennsylvania State Univ., University Park, PA (United States); Avramova, Maria N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gergar, Marcus [Pennsylvania State Univ., University Park, PA (United States)

    2015-10-26

    This milestone report is a summary of work performed in support of expansion of the validation and verification (V&V) matrix for the thermal-hydraulic subchannel code, CTF. The focus of this study is on validating the void drift modeling capabilities of CTF and verifying the supporting models that impact the void drift phenomenon. CTF uses a simple turbulent-diffusion approximation to model lateral cross-flow due to turbulent mixing and void drift. The void drift component of the model is based on the Lahey and Moody model. The models are a function of two-phase mass, momentum, and energy distribution in the system; therefore, it is necessary to correctly model the ow distribution in rod bundle geometry as a first step to correctly calculating the void distribution due to void drift.

  15. The cosmic web in CosmoGrid void regions

    Science.gov (United States)

    Rieder, Steven; van de Weygaert, Rien; Cautun, Marius; Beygu, Burcu; Portegies Zwart, Simon

    2016-10-01

    We study the formation and evolution of the cosmic web, using the high-resolution CosmoGrid ΛCDM simulation. In particular, we investigate the evolution of the large-scale structure around void halo groups, and compare this to observations of the VGS-31 galaxy group, which consists of three interacting galaxies inside a large void. The structure around such haloes shows a great deal of tenuous structure, with most of such systems being embedded in intra-void filaments and walls. We use the Nexus+} algorithm to detect walls and filaments in CosmoGrid, and find them to be present and detectable at every scale. The void regions embed tenuous walls, which in turn embed tenuous filaments. We hypothesize that the void galaxy group of VGS-31 formed in such an environment.

  16. "Dark energy" in the Local Void

    Science.gov (United States)

    Villata, M.

    2012-05-01

    The unexpected discovery of the accelerated cosmic expansion in 1998 has filled the Universe with the embarrassing presence of an unidentified "dark energy", or cosmological constant, devoid of any physical meaning. While this standard cosmology seems to work well at the global level, improved knowledge of the kinematics and other properties of our extragalactic neighborhood indicates the need for a better theory. We investigate whether the recently suggested repulsive-gravity scenario can account for some of the features that are unexplained by the standard model. Through simple dynamical considerations, we find that the Local Void could host an amount of antimatter (˜5×1015 M ⊙) roughly equivalent to the mass of a typical supercluster, thus restoring the matter-antimatter symmetry. The antigravity field produced by this "dark repulsor" can explain the anomalous motion of the Local Sheet away from the Local Void, as well as several other properties of nearby galaxies that seem to require void evacuation and structure formation much faster than expected from the standard model. At the global cosmological level, gravitational repulsion from antimatter hidden in voids can provide more than enough potential energy to drive both the cosmic expansion and its acceleration, with no need for an initial "explosion" and dark energy. Moreover, the discrete distribution of these dark repulsors, in contrast to the uniformly permeating dark energy, can also explain dark flows and other recently observed excessive inhomogeneities and anisotropies of the Universe.

  17. Warmth elevating the depths: shallower voids with warm dark matter

    Science.gov (United States)

    Yang, Lin F.; Neyrinck, Mark C.; Aragón-Calvo, Miguel A.; Falck, Bridget; Silk, Joseph

    2015-08-01

    Warm dark matter (WDM) has been proposed as an alternative to cold dark matter (CDM), to resolve issues such as the apparent lack of satellites around the Milky Way. Even if WDM is not the answer to observational issues, it is essential to constrain the nature of the dark matter. The effect of WDM on haloes has been extensively studied, but the small-scale initial smoothing in WDM also affects the present-day cosmic web and voids. It suppresses the cosmic `sub-web' inside voids, and the formation of both void haloes and subvoids. In N-body simulations run with different assumed WDM masses, we identify voids with the ZOBOV algorithm, and cosmic-web components with the ORIGAMI algorithm. As dark-matter warmth increases (i.e. particle mass decreases), void density minima grow shallower, while void edges change little. Also, the number of subvoids decreases. The density field in voids is particularly insensitive to baryonic physics, so if void density profiles and minima could be measured observationally, they would offer a valuable probe of the nature of dark matter. Furthermore, filaments and walls become cleaner, as the substructures in between have been smoothed out; this leads to a clear, mid-range peak in the density PDF.

  18. The Formation of Verbal Behaviors for Multiple Handicapped Children

    OpenAIRE

    進, 一鷹; シン, カズタカ; Shin, Kazutaka

    1996-01-01

    This paper is designed to carry out research into the formation of verbal behaviors for multiple handicapped children. Umezu (1980) classified sign system from the angle of genesis and construction principle of signs. The sign system activity plays the central role in the self regulation activity of behaviors. Sign system consists of aboriginal sign system and constructive sign system. Constructive sign system consists of symbolic sign system and non-symbolic sign system. Symbolic sign system...

  19. Demarketing of Tobacco Products and Consumers Behavior Formation

    Directory of Open Access Journals (Sweden)

    Barbara Jacennik

    2008-03-01

    Full Text Available Demarketing of tobacco products includes methods aimed at changing the consumer behavior and the marketing environment. The main strategies consist of price manipulation, anti-smoking advertising, regulations restricting or banning tobacco advertising, limitations of distribution or consumption of tobacco products, and warning messages on packages and advertisements. These measures influence either directly or indirectly the following psychosocial and environmental variables: health beliefs, social attractiveness of smoking, accessibility of tobacco products and associated behaviors. The article presents a review of international research on the demarketing of tobacco and its effects for the formation and change of health behavior.

  20. Emergent Behavior of Multi-Vehicle Formations Using Extremum Seeking

    NARCIS (Netherlands)

    Brodecki, M.; Subbarao, K.; Chu, Q.P.

    2013-01-01

    Emergent behavior of a formation flight control system based on an advanced extremum seeking algorithm is investigated. The control system was implemented on a nonlinear high fidelity aircraft model and combined with a wake vortex model in order to accurately represent the aerodynamic coupling

  1. Epigenetic mechanisms in experience-driven memory formation and behavior

    Science.gov (United States)

    Puckett, Rosemary E; Lubin, Farah D

    2011-01-01

    Epigenetic mechanisms have long been associated with the regulation of gene-expression changes accompanying normal neuronal development and cellular differentiation; however, until recently these mechanisms were believed to be statically quiet in the adult brain. Behavioral neuroscientists have now begun to investigate these epigenetic mechanisms as potential regulators of gene-transcription changes in the CNS subserving synaptic plasticity and long-term memory (LTM) formation. Experimental evidence from learning and memory animal models has demonstrated that active chromatin remodeling occurs in terminally differentiated postmitotic neurons, suggesting that these molecular processes are indeed intimately involved in several stages of LTM formation, including consolidation, reconsolidation and extinction. Such chromatin modifications include the phosphorylation, acetylation and methylation of histone proteins and the methylation of associated DNA to subsequently affect transcriptional gene readout triggered by learning. The present article examines how such learning-induced epigenetic changes contribute to LTM formation and influence behavior. In particular, this article is a survey of the specific epigenetic mechanisms that have been demonstrated to regulate gene expression for both transcription factors and growth factors in the CNS, which are critical for LTM formation and storage, as well as how aberrant epigenetic processing can contribute to psychological states such as schizophrenia and drug addiction. Together, the findings highlighted in this article support a novel role for epigenetic mechanisms in the adult CNS serving as potential key molecular regulators of gene-transcription changes necessary for LTM formation and adult behavior. PMID:22126252

  2. Epigenetic mechanisms in experience-driven memory formation and behavior.

    Science.gov (United States)

    Puckett, Rosemary E; Lubin, Farah D

    2011-10-01

    Epigenetic mechanisms have long been associated with the regulation of gene-expression changes accompanying normal neuronal development and cellular differentiation; however, until recently these mechanisms were believed to be statically quiet in the adult brain. Behavioral neuroscientists have now begun to investigate these epigenetic mechanisms as potential regulators of gene-transcription changes in the CNS subserving synaptic plasticity and long-term memory (LTM) formation. Experimental evidence from learning and memory animal models has demonstrated that active chromatin remodeling occurs in terminally differentiated postmitotic neurons, suggesting that these molecular processes are indeed intimately involved in several stages of LTM formation, including consolidation, reconsolidation and extinction. Such chromatin modifications include the phosphorylation, acetylation and methylation of histone proteins and the methylation of associated DNA to subsequently affect transcriptional gene readout triggered by learning. The present article examines how such learning-induced epigenetic changes contribute to LTM formation and influence behavior. In particular, this article is a survey of the specific epigenetic mechanisms that have been demonstrated to regulate gene expression for both transcription factors and growth factors in the CNS, which are critical for LTM formation and storage, as well as how aberrant epigenetic processing can contribute to psychological states such as schizophrenia and drug addiction. Together, the findings highlighted in this article support a novel role for epigenetic mechanisms in the adult CNS serving as potential key molecular regulators of gene-transcription changes necessary for LTM formation and adult behavior.

  3. Assembly of filamentary void galaxy configurations

    Science.gov (United States)

    Rieder, Steven; van de Weygaert, Rien; Cautun, Marius; Beygu, Burcu; Portegies Zwart, Simon

    2013-10-01

    We study the formation and evolution of filamentary configurations of dark matter haloes in voids. Our investigation uses the high-resolution Λ cold dark matter simulation CosmoGrid to look for void systems resembling the VGS_31 elongated system of three interacting galaxies that was recently discovered by the Void Galaxy Survey inside a large void in the Sloan Digital Sky Survey galaxy redshift survey. H I data revealed these galaxies to be embedded in a common elongated envelope, possibly embedded in intravoid filament. In the CosmoGrid simulation we look for systems similar to VGS_31 in mass, size and environment. We find a total of eight such systems. For these systems, we study the distribution of neighbour haloes, the assembly and evolution of the main haloes and the dynamical evolution of the haloes, as well as the evolution of the large-scale structure in which the systems are embedded. The spatial distribution of the haloes follows that of the dark matter environment. We find that VGS_31-like systems have a large variation in formation time, having formed between 10 Gyr ago and the present epoch. However, the environments in which the systems are embedded evolved to resemble each other substantially. Each of the VGS_31-like systems is embedded in an intravoid wall, that no later than z = 0.5 became the only prominent feature in its environment. While part of the void walls retain a rather featureless character, we find that around half of them are marked by a pronounced and rapidly evolving substructure. Five haloes find themselves in a tenuous filament of a few h-1 Mpc long inside the intravoid wall. Finally, we compare the results to observed data from VGS_31. Our study implies that the VGS_31 galaxies formed in the same (proto)filament, and did not meet just recently. The diversity amongst the simulated halo systems indicates that VGS_31 may not be typical for groups of galaxies in voids.

  4. Air void clustering : [technical summary].

    Science.gov (United States)

    2015-06-01

    Air void clustering around coarse aggregate in concrete has been : identified as a potential source of low strengths in concrete mixes by : several Departments of Transportation around the country. Research : was carried out to (1) develop a quantita...

  5. Molecular dynamics simulations of void defects in the energetic material HMX.

    Science.gov (United States)

    Duan, Xiao Hui; Li, Wen Peng; Pei, Chong Hua; Zhou, Xiao Qing

    2013-09-01

    A molecular dynamics (MD) simulation was carried out to characterize the dynamic evolution of void defects in crystalline octahydro-1, 3, 5, 7-tetranitro-1, 3, 5, 7-tetrazocine (HMX). Different models were constructed with the same concentration of vacancies (10 %) to discuss the size effects of void. Energetic ground state properties were determined by annealing simulations. The void formation energy per molecule removed was found to be 55-63 kcal/mol(-1), and the average binding energy per molecule was between 32 and 34 kcal/mol(-1) according to the change in void size. Voids with larger size had lower formation energy. Local binding energies for molecules directly on the void surface decreased greatly compared to those in defect-free lattice, and then gradually increased until the distance away from the void surface was around 10 Å. Analysis of 1 ns MD simulations revealed that the larger the void size, the easier is void collapse. Mean square displacements (MSDs) showed that HMX molecules that had collapsed into void present liquid structure characteristics. Four unique low-energy conformers were found for HMX molecules in void: two whose conformational geometries corresponded closely to those found in HMX polymorphs and two, additional, lower energy conformers that were not seen in the crystalline phases. The ratio of different conformers changed with the simulated temperature, in that the ratio of α conformer increased with the increase in temperature.

  6. A theoretical analysis of the electromigration-induced void morphological evolution under high current density

    Science.gov (United States)

    Wang, Yuexing; Yao, Yao

    2017-10-01

    In this work, analysis of electromigration-induced void morphological evolution in solder interconnects is performed based on mass diffusion theory. The analysis is conducted for three typical experimentally observed void shapes: circular, ellipse, and cardioid. Void morphological evolution is governed by the competition between the electric field and surface capillary force. In the developed model, both the electric field and capillary force on the void's surface are solved analytically. Based on the mass conversation principle, the normal velocity on the void surface during diffusion is obtained. The void morphological evolution behavior is investigated, and a physical model is developed to predict void collapse to a crack or to split into sub-voids under electric current. It is noted that when the electric current is being applied from the horizontal direction, a circular void may either move stably along the electric current direction or collapse to a finger shape, depending on the relative magnitude of the electric current and surface capillary force. However, the elliptical-shaped void will elongate along the electric current direction and finally collapse to the finger shape. On the other hand, the cardioid-shaped void could bifurcate into two sub-voids when the electric current reaches a critical value. The theoretical predictions agree well with the experimental observations.

  7. Alignment of voids in the cosmic web

    NARCIS (Netherlands)

    Platen, Erwin; van de Weygaert, Rien; Jones, Bernard J. T.

    2008-01-01

    We investigate the shapes and mutual alignment of voids in the large-scale matter distribution of a Lambda cold dark matter (Lambda CDM) cosmology simulation. The voids are identified using the novel watershed void finder (WVF) technique. The identified voids are quite non-spherical and slightly

  8. Finding Brazing Voids by Holography

    Science.gov (United States)

    Galluccio, R.

    1986-01-01

    Vibration-induced interference fringes reveal locations of defects. Holographic apparatus used to view object while vibrated ultrasonically. Interference fringes in hologram reveal brazing defects. Holographic technique locates small voids in large brazed joints. Identifies unbrazed regions 1 in. to second power (6 cm to the second power) or less in area.

  9. On cavitation instabilities with interacting voids

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    2012-01-01

    When a single void grows in an elastic–plastic material a cavitation instability may occur, if the stress triaxiality is sufficiently high. The effect of neighbouring voids on such unstable cavity growth is studied here by comparing two different models. The first model considers a periodic array...... voids so far apart that the radius of the plastic zone around each void is less than 1% of the current spacing between the voids, can still affect each others at the occurrence of a cavitation instability such that one void stops growing while the other grows in an unstable manner. On the other hand...

  10. The cosmic web in CosmoGrid void regions

    NARCIS (Netherlands)

    Rieder, Steven; van de Weygaert, Rien; Cautun, Marius; Beygu, Burcu; Portegies Zwart, Simon

    2016-01-01

    We study the formation and evolution of the cosmic web, using the high-resolution CosmoGrid ΛCDM simulation. In particular, we investigate the evolution of the large-scale structure around void halo groups, and compare this to observations of the VGS-31 galaxy group, which consists of three

  11. Constitutive modeling of rate dependence and microinertia effects in porous-plastic materials with multi-sized voids (MSVs)

    KAUST Repository

    Liu, Jinxing

    2012-11-27

    Micro-voids of varying sizes exist in most metals and alloys. Both experiments and numerical studies have demonstrated the critical influence of initial void sizes on void growth. The classical Gurson-Tvergaard-Needleman model summarizes the influence of voids with a single parameter, namely the void-volume fraction, excluding any possible effects of the void-size distribution. We extend our newly proposed model including the multi-sized void (MSV) effect and the void-interaction effect for the capability of working for both moderate and high loading rate cases, where either rate dependence or microinertia becomes considerable or even dominant. Parametric studies show that the MSV-related competitive mechanism among void growth leads to the dependence of the void growth rate on void size, which directly influences the void\\'s contribution to the total energy composition. We finally show that the stress-strain constitutive behavior is also affected by this MSV-related competitive mechanism. The stabilizing effect due to rate sensitivity and microinertia is emphasized. © 2013 IOP Publishing Ltd.

  12. The dipole moment of a wall-charged void in a bulk dielectric

    DEFF Research Database (Denmark)

    McAllister, Iain Wilson

    1993-01-01

    The dipole moment of a wall-charged void is examined with reference to the spatial extent of the surface charge density σ and the distribution of this charge. The salient factors influencing the void dipole moment are also examined. From a study of spherical voids, it is shown that, although the σ......-distribution influences the dipole moment, the spatial extent of σ has a greater influence. This behavior is not unexpected. For a void of fixed dimensions, the smaller the charged surface area, the greater is the charges, and thus the greater the dipole moment...

  13. Tracing the gravitational potential using cosmic voids

    Science.gov (United States)

    Nadathur, Seshadri; Hotchkiss, Shaun; Crittenden, Robert

    2017-06-01

    The properties of large underdensities in the distribution of galaxies in the Universe, known as cosmic voids, are potentially sensitive probes of fundamental physics. We use data from the MultiDark suite of N-body simulations and multiple halo occupation distribution mocks to study the relationship between galaxy voids, identified using a watershed void-finding algorithm, and the gravitational potential Φ. We find that the majority of galaxy voids correspond to local density minima in larger scale overdensities, and thus lie in potential wells. However, a subset of voids can be identified that closely trace maxima of the gravitational potential and thus stationary points of the velocity field. We identify a new void observable, λv, which depends on a combination of the void size and the average galaxy density contrast within the void, and show that it provides a good proxy indicator of the potential at the void location. A simple linear scaling of Φ as a function of λv is found to hold, independent of the redshift and properties of the galaxies used as tracers of voids. We provide an accurate fitting formula to describe the spherically averaged potential profile Φ(r) about void centre locations. We discuss the importance of these results for the understanding of the evolution history of voids, and for their use in precision measurements of the integrated Sachs-Wolfe effect, gravitational lensing and peculiar velocity distortions in redshift space.

  14. Metallicities of Galaxies in the Lynx-Cancer Void

    Science.gov (United States)

    Kniazev, A.; Pustilnik, S.; Tepliakova, A.; Burenkov, A.

    Does the void environment have a sizable effect on the evolution of dwarf galaxies? If yes, the best probes should be the most fragile least massive dwarfs. We compiled a sample of about one hundred dwarfs with MB in the range -12to -18 mag, falling within the nearby Lynx-Cancer void. The goal is to study their evolutionary parameters - gas metallicity and gas mass-fraction, and to address the epoch of the first substantial episode of Star Formation. Here we present and discuss the results of O/H measurements in 38 void galaxies, among which several of the most metal-poor galaxies are found with an oxygen abundance of 12 + log(O/H) = 7. 12-7.3 dex.

  15. Redshift-space distortions around voids

    Science.gov (United States)

    Cai, Yan-Chuan; Taylor, Andy; Peacock, John A.; Padilla, Nelson

    2016-11-01

    We have derived estimators for the linear growth rate of density fluctuations using the cross-correlation function (CCF) of voids and haloes in redshift space. In linear theory, this CCF contains only monopole and quadrupole terms. At scales greater than the void radius, linear theory is a good match to voids traced out by haloes; small-scale random velocities are unimportant at these radii, only tending to cause small and often negligible elongation of the CCF near its origin. By extracting the monopole and quadrupole from the CCF, we measure the linear growth rate without prior knowledge of the void profile or velocity dispersion. We recover the linear growth parameter β to 9 per cent precision from an effective volume of 3( h-1Gpc)3 using voids with radius >25 h-1Mpc. Smaller voids are predominantly sub-voids, which may be more sensitive to the random velocity dispersion; they introduce noise and do not help to improve measurements. Adding velocity dispersion as a free parameter allows us to use information at radii as small as half of the void radius. The precision on β is reduced to 5 per cent. Voids show diverse shapes in redshift space, and can appear either elongated or flattened along the line of sight. This can be explained by the competing amplitudes of the local density contrast, plus the radial velocity profile and its gradient. The distortion pattern is therefore determined solely by the void profile and is different for void-in-cloud and void-in-void. This diversity of redshift-space void morphology complicates measurements of the Alcock-Paczynski effect using voids.

  16. Size effects on void growth in single crystals with distributed voids

    DEFF Research Database (Denmark)

    Borg, Ulrik; Niordson, Christian Frithiof; Kysar, J.W.

    2008-01-01

    The effect of void size on void growth in single crystals with uniformly distributed cylindrical voids is studied numerically using a finite deformation strain gradient crystal plasticity theory with an intrinsic length parameter. A plane strain cell model is analyzed for a single crystal...... with three in-plane slip systems. It is observed that small voids allow much larger overall stress levels than larger voids for all the stress triaxialities considered. The amount of void growth is found to be suppressed for smaller voids at low stress triaxialities. Significant differences are observed...

  17. Size-Effects in Void Growth

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof

    2005-01-01

    The size-effect on ductile void growth in metals is investigated. The analysis is based on unit cell models both of arrays of cylindrical voids under plane strain deformation, as well as arrays of spherical voids using an axisymmetric model. A recent finite strain generalization of two higher order...... models. This increased resistance to void growth, due to gradient hardening, is accompanied by an increase in the overall strength for the material. Furthermore, for increasing initial void volume fraction, it is shown that the effect of gradients becomes more important to the overall response but less...

  18. Voiding postponement in children-a systematic review.

    Science.gov (United States)

    von Gontard, Alexander; Niemczyk, Justine; Wagner, Catharina; Equit, Monika

    2016-08-01

    Voiding postponement (VP) has been defined as a habitual postponement of micturition using holding maneuvers. VP can represent both a symptom, as well as a condition. As divergent definitions are used internationally, the aim was to review the current state of knowledge on VP and provide recommendations for assessment, diagnosis and treatment. A Scopus and a Pubmed search was conducted, entering the terms 'voiding postponement' without any restrictions or specifications. Other publications relevant to the topic were added. VP can represent a symptom in healthy children. As a condition, VP in combination with nocturnal enuresis (NE) is a subtype of non-monosymptomatic NE. Most studies have focused on daytime urinary incontinence (DUI) with VP, or more aptly termed voiding postponement incontinence (VPI). It is a behaviorally defined syndrome, i.e., by the habitual deferral of micturition and DUI. VPI is associated with a low micturition frequency, urgency and behavioral problems. The most common comorbid disorder is oppositional defiant disorder (ODD). VP as a symptom and VPI as a condition should be differentiated. VPI is a common disorder with many associated problems and disorders. Urotherapy and timed voiding are the main treatment approaches. Due to the high rate of comorbid ODD, other forms of treatment, especially cognitive behavioral therapy, are often needed.

  19. Systemic atherosclerosis and voiding symptom.

    Science.gov (United States)

    Yeniel, A Ozgur; Ergenoglu, A Mete; Meseri, Reci; Ari, Anıl; Sancar, Ceren; Itil, Ismail Mete

    2017-03-01

    To evaluate the effect of atherosclerosis on the storage and voiding symptoms of the bladder in women with overactive bladder (OAB). We retrospectively reviewed the charts of women with OAB who were evaluated between 2013 and 2015 in our urogynecology unit. Charts were assessed for history, examination findings, urinary diary, quality of life (QOL) questionnaires, urodynamic studies (UDSs), and four main risk factors for atherosclerosis: hypertension, diabetes mellitus, smoking, and hyperlipidemia. In a previous study, these were defined as vascular risk factors. Cases were excluded for insufficient data, diabetes mellitus with dysregulated blood glucose, or prolapse greater than 1cm to avoid confusing bladder outlet obstruction. We included 167 eligible cases in this study. We evaluated storage and voiding symptoms such as frequency, nocturia, residual urine volume, and voiding difficulties and UDS findings such as maximum bladder capacity, first desire, strong desire, detrusor overactivity, and bladder contractility index. The vascular risk score was categorized as "no risk" if the woman did not have any of the four risk factors and "at risk" if she had any of the factors. Independent sample t-test and chi-square tests were performed for analyses. Among the participants (n=167), 71.9% had at least one vascular risk factor. Those who were at risk were facing significantly more wet-type OAB (p=0.003) and nocturia (p=0.023). Moreover, mean age (p=0.008) and mean gravidity (p=0.020) were significantly higher in the at-risk group, whereas mean total nocturia QOL questionnaire scores (p=0.029) were significantly lower. Our findings suggest that aging and atherosclerosis may be associated with severe OAB and poorer QOL. Nocturia and related parameters of poor quality can be explained by impaired bladder neck perfusion. Future trials need to assess vascular and molecular changes in women with OAB. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Thermal stress induced voids in nanoscale copper interconnects by in-situ TEM heating

    Science.gov (United States)

    An, Jin Ho

    Stress induced void formation in Cu interconnects, due to thermal stresses generated during the processing of semiconductors, is an increasing reliability issue in the semiconductor industry as Cu interconnects are being downscaled to follow the demand for faster chip speed. In this work, 1.8 micron and 180 nm wide Cu interconnects, fabricated by Freescale Semiconductors, were subjected to thermal cycles, in-situ in the TEM, to investigate the stress relaxation mechanisms as a function of interconnect linewidth. The experiments show that the 1.8 micron Cu interconnect lines relax the thermal stresses through dislocation nucleation and motion while the Cu interconnect 180 nm lines exhibit void formation. Void formation in 180 nm lines occurs predominantly at triple junctions where the Ta diffusion barrier meets a Cu grain boundary. In order to understand void formation in 180 nm lines, the grain orientation and local stresses are determined. In particular, Nanobeam Diffraction (NBD) in the TEM is used to obtain the diffraction pattern of each grain, from which the crystal orientation is evaluated by the ACT (Automated Crystallography for TEM) software. In addition, 2D Finite Element Method (FEM) simulations are performed using the Object Oriented Finite Modeling (OOF2) software to correlate grain orientation with local stresses, and consequently void formation. According to the experimental and simulation results obtained, void formation in 180nm Cu interconnects does not seem to be solely dependent on local stresses, but a combination of diffusion paths available, stress gradients and possibly the presence of defects. In addition, based on the in-situ TEM observations, void growth seems to occur through grain boundary and/or interfacial diffusion. However, in-situ STEM observations of fully opened voids post-failure show pileup of material at the Cu grain surfaces. This means that surface or interface diffusion is also very active during void growth in the presence

  1. Nocturia: The circadian voiding disorder

    Directory of Open Access Journals (Sweden)

    Jin Wook Kim

    2016-05-01

    Full Text Available Nocturia is a prevalent condition of waking to void during the night. The concept of nocturia has evolved from being a symptomatic aspect of disease associated with the prostate or bladder to a form of lower urinary tract disorder. However, recent advances in circadian biology and sleep science suggest that it might be important to consider nocturia as a form of circadian dysfunction. In the current review, nocturia is reexamined with an introduction to sleep disorders and recent findings in circadian biology in an attempt to highlight the importance of rediscovering nocturia as a problem of chronobiology.

  2. Fluid intake and voiding; habits and health knowledge in a young, healthy population.

    Science.gov (United States)

    Das, Rebekah N; Grimmer-Somers, Karen A

    2012-01-01

    Health professionals commonly advise patients with incontinence and other lower urinary tract symptoms about modifiable contributing factors such as drinking and voiding habits. Poor drinking and voiding habits may begin early in life, before symptoms emerge. However, little is known about the habits and knowledge young people have regarding healthy drinking and voiding behaviors. This research aimed to assess the habits and health knowledge of young people regarding fluid intake and voiding. A questionnaire was used to assess the drinking and voiding behaviors of first year university students and their knowledge about healthy fluid intake and voiding. The average daily fluid intake was >2 L/day for both genders. Poor drinking and voiding habits (such as high consumption of caffeinated drinks and alcohol, or nocturia) were common. Widely reported myths about the benefits of a high fluid intake were commonly believed. More informed public education regarding healthy fluid intake, and drinking and voiding habits, is required as part of the effort to reduce the development of lower urinary tract symptoms, including incontinence.

  3. Cosmology with void-galaxy correlations.

    Science.gov (United States)

    Hamaus, Nico; Wandelt, Benjamin D; Sutter, P M; Lavaux, Guilhem; Warren, Michael S

    2014-01-31

    Galaxy bias, the unknown relationship between the clustering of galaxies and the underlying dark matter density field is a major hurdle for cosmological inference from large-scale structure. While traditional analyses focus on the absolute clustering amplitude of high-density regions mapped out by galaxy surveys, we propose a relative measurement that compares those to the underdense regions, cosmic voids. On the basis of realistic mock catalogs we demonstrate that cross correlating galaxies and voids opens up the possibility to calibrate galaxy bias and to define a static ruler thanks to the observable geometric nature of voids. We illustrate how the clustering of voids is related to mass compensation and show that volume-exclusion significantly reduces the degree of stochasticity in their spatial distribution. Extracting the spherically averaged distribution of galaxies inside voids from their cross correlations reveals a remarkable concordance with the mass-density profile of voids.

  4. Modeling void growth and movement with phase change in thermal energy storage canisters

    Science.gov (United States)

    Darling, Douglas; Namkoong, David; Skarda, J. Raymond Lee

    1993-01-01

    A scheme was developed to model the thermal hydrodynamic behavior of thermal energy storage salts. The model included buoyancy, surface tension, viscosity, phases change with density difference, and void growth and movement. The energy, momentum, and continuity equations were solved using a finite volume formulation. The momentum equation was divided into two pieces. The void growth and void movement are modeled between the two pieces of the momentum equations. Results showed this scheme was able to predict the behavior of thermal energy storage salts.

  5. Evaluation of the Air Void Analyzer

    Science.gov (United States)

    2013-07-01

    glycerin -based blue viscous release fluid. This version was first used in June 1994 for testing in Michigan, Wisconsin, Texas, and Iowa; and the...sample of mortar is obtained from concrete, it is injected into the base of the column with the glycerin -based blue release fluid, and the mortar sample...separation when measuring. Void rise speeds are reduced in the higher viscosity glycerin solution. Once the voids are freed from the mortar, the voids

  6. Void structure of concrete with superabsorbent polymers and its relation to frost resistance of concrete

    DEFF Research Database (Denmark)

    Hasholt, Marianne Tange; Jensen, Ole Mejlhede; Laustsen, Sara

    2013-01-01

    surfactant prior to concrete mixing. The method comprises rinsing of the SAP with ethanol. This effectively removes the surfactant. Freeze-thaw testing of concrete with rinsed and non-rinsed SAP shows that for equal dosages of SAP, the extra air entrained due to surfactant is considerable and can make......Superabsorbent polymers (SAP) can be used to control air void formation in concrete. However, due to surfactant left on suspension polymerized SAP particles during production, they may not only create SAP voids but also entrain extra air. In the present investigation, a method is tested to remove...... the difference between poor and satisfactory frost-resistance. Furthermore, the results indicate that voids created directly by SAP protect concrete against frost deterioration just like other air voids; if the concrete contains enough SAP voids, these alone can provide sufficient frost resistance. © 2013 RILEM....

  7. Partial discharge patterns and surface deterioration in voids in filled and unfilled epoxy

    DEFF Research Database (Denmark)

    Holbøll, Joachim; Henriksen, Mogens

    1992-01-01

    investigated by scanning electron microscopy for voids exposed to PD as well as voids without discharges. Different kinds of surface deterioration were found. An attempt was made to establish a relationship between aging phenomena as exhibited by void surface changes and discharge patterns......Results are presented from analyses of pulses from partial discharges (PDs) in single spherical voids in filled and unfilled epoxy plastic and related to the observed surface deterioration. The filler types used were dolomite, alumina, and silica. Long-time aging tests including pulse phase....../height analyses were performed over a period of 2400 h and showed very characteristic discharge patterns for each material combination. A unique behavior with regard to changes of pulse repetition rate and maximum apparent charge was observed for PD in alumina- and silica-filled epoxy. The void surfaces were...

  8. The darkness that shaped the void : Dark energy and cosmic voids

    NARCIS (Netherlands)

    Bos, E. G. Patrick; van de Weygaert, Rien; Dolag, Klaus; Pettorino, Valeria

    2012-01-01

    We assess the sensitivity of void shapes to the nature of dark energy that was pointed out in recent studies and also investigate whether or not void shapes are useable as an observational probe in galaxy redshift surveys. Our focus is on the evolution of the mean void ellipticity and its underlying

  9. A molecular dynamics study of void initiation and growth in monocrystalline and nanocrystalline copper

    Science.gov (United States)

    Traiviratana, Sirirat

    MD simulations in monocrystalline and nanocrystalline copper were carried out with LAMMPS to reveal void growth mechanisms. The specimens were subjected to both tensile uniaxial and hydrostatic strains; the results confirm that the emission of (shear) loops is the primary mechanism of void growth. The expansion of the loops and their cross slip leads to the severely work hardened layer surrounding a growing void. Calculations were carried out on voids with different sizes, and a size dependence of the stress response to emitted dislocations was observed, in disagreement with the Gurson model [1] which is scale independent. The growth of voids simulated by MD is compared with the Cocks-Ashby constitutive model and significant agreement is found. The density of geometrically-necessary dislocations as a function of void size is calculated based on the emission of shear loops and their outward propagation. Calculations were also carried out for a void at the interface between two grains sharing a tilt boundary. The results show similar dislocation behaviors. A code that uses Voronoi tessellation for constructing nanocrystalline structures was developed and used to prepare the structures for simulations. Nanocrystal simulations reveal grain sliding and grain rotation as the nanocrystal deformed. Voids were nucleated at grain junctions and grew to coalescence as dislocations accommodated the material transfer. A code that can be used during post-processing to extract useful dislocation information from MD simulation data was partially developed and proved the feasibility of automatically analyzing dislocations.

  10. Partial discharges in ellipsoidal and spheroidal voids

    DEFF Research Database (Denmark)

    Crichton, George C; Karlsson, P. W.; Pedersen, Aage

    1989-01-01

    Transients associated with partial discharges in voids can be described in terms of the charges induced on the terminal electrodes of the system. The relationship between the induced charge and the properties which are usually measured is discussed. The method is illustrated by applying it to a s...... it to a spheroidal void located in a simple disk-type spacer...

  11. International business responses to institutional voids

    NARCIS (Netherlands)

    Doh, J.; Rodrigues, S.; Saka-Helmhout, A.U.; Makhija, M.

    2017-01-01

    For nearly two decades, scholars in international business and management have explored the implications of institutional voids for firm strategy and structure. Although institutional voids offer both opportunities and challenges, they have largely been associated with firms’ efforts to avoid or

  12. Pores and Void in Asclepiades' Physical Theory.

    Science.gov (United States)

    Leith, David

    2012-01-01

    This paper examines a fundamental, though relatively understudied, aspect of the physical theory of the physician Asclepiades of Bithynia, namely his doctrine of pores. My principal thesis is that this doctrine is dependent on a conception of void taken directly from Epicurean physics. The paper falls into two parts: the first half addresses the evidence for the presence of void in Asclepiades' theory, and concludes that his conception of void was basically that of Epicurus; the second half focuses on the precise nature of Asclepiadean pores, and seeks to show that they represent void interstices between the primary particles of matter which are the constituents of the human body, and are thus exactly analogous to the void interstices between atoms within solid objects in Epicurus' theory.

  13. Effects of Grain Boundaries and Dislocation Cell Walls on Void Nucleation and Growth in Aluminium during Fast Neutron Irradiation

    DEFF Research Database (Denmark)

    Horsewell, Andy; Rahman, F. A.; Singh, Bachu Narain

    1983-01-01

    High purity aluminium irradiated to fluences between 2 multiplied by 10**2**1 and 1 multiplied by 10**2**4 n. m** minus **2 (E greater than 1 Mev) at 120 degree C has been investigated by TEM. A void denuded zone is seen both at grain boundaries and dislocation cell walls. Enhanced void formation...

  14. Calcium polyphosphate particulates for bone void filler applications.

    Science.gov (United States)

    Pilliar, Robert M; Kandel, Rita A; Grynpas, Marc D; Theodoropoulos, John; Hu, Youxin; Allo, Bedilu; Changoor, Adele

    2017-05-01

    This study investigates the characteristics of porous calcium polyphosphate particulates (CPPp) formed using two different processing treatments as bone void fillers in non- or minimally load-bearing sites. The two calcium polyphosphate particulate variants (grades) were formed using different annealing conditions during particulate preparation to yield either more slowly degrading calcium polyphosphate particulates (SD-CPPp) or faster degrading particulates (FD-CPPp) as suggested by a previous degradation study conducted in vitro (Hu et al., Submitted for publication 2016). The two CPPp grades were compared as bone void fillers in vivo by implanting particulates in defects created in rabbit femoral condyle sites (critical size defects). The SD-CPPp and FD-CPPp were implanted for 4- and 16-week periods. The in vivo study indicated a significant difference in amount of new bone formed in the prepared sites with SD-CPPp resulting in more new bone formation compared with FD-CPPp. The lower bone formation characteristic of the FD-CPPp was attributed to its faster degradation rate and resulting higher local concentration of released polyphosphate degradation products. The study results indicate the importance of processing conditions on preparing calcium polyphosphate particulates for potential use as bone void fillers in nonload-bearing sites. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 874-884, 2017. © 2016 Wiley Periodicals, Inc.

  15. Dwarf Galaxies in Voids: Dark Matter Halos and Gas Cooling

    Directory of Open Access Journals (Sweden)

    Matthias Hoeft

    2010-01-01

    Full Text Available Galaxy surveys have shown that luminous galaxies are mainly distributed in large filaments and galaxy clusters. The remaining large volumes are virtually devoid of luminous galaxies. This is in concordance with the formation of the large-scale structure in the universe as derived from cosmological simulations. However, the numerical results indicate that cosmological voids are abundantly populated with dark matter haloes which may in principle host dwarf galaxies. Observational efforts have in contrast revealed that voids are apparently devoid of dwarf galaxies. We investigate the formation of dwarf galaxies in voids by hydrodynamical cosmological simulations. Due to the cosmic ultraviolet background radiation low-mass haloes show generally a reduced baryon fraction. We determine the characteristic mass below which dwarf galaxies are baryon deficient. We show that the circular velocity below which the accretion of baryons is suppressed is approximately 40 kms−1. The suppressed baryon accretion is caused by the photo-heating due to the UV background. We set up a spherical halo model and show that the effective equation of the state of the gas in the periphery of dwarf galaxies determines the characteristic mass. This implies that any process which heats the gas around dwarf galaxies increases the characteristic mass and thus reduces the number of observable dwarf galaxies.

  16. Practical statistics for the voids between galaxies

    Directory of Open Access Journals (Sweden)

    Zaninetti L.

    2010-01-01

    Full Text Available The voids between galaxies are identified with the volumes of the Poisson Voronoi tessellation. Two new survival functions for the apparent radii of voids are derived. The sectional normalized area of the Poisson Voronoi tessellation is modelled by the Kiang function and by the exponential function. Two new survival functions with equivalent sectional radius are therefore derived; they represent an alternative to the survival function of voids between galaxies as given by the self-similar distribution. The spatial appearance of slices of the 2dF Galaxy Redshift Survey is simulated.

  17. Practical Statistics for the Voids Between Galaxies

    Directory of Open Access Journals (Sweden)

    Zaninetti, L.

    2010-12-01

    Full Text Available The voids between galaxies are identified withthe volumes of the Poisson Voronoi tessellation.Two new survival functions for the apparent radii of voids are derived. The sectional normalized area ofthe Poisson Voronoi tessellation is modelledby the Kiang function and by the exponential function. Two new survival functions with equivalent sectional radius are therefore derived; they represent an alternative to the survival function of voids between galaxies as given by the self-similar distribution. The spatial appearance of slices of the 2dF Galaxy Redshift Survey is simulated.

  18. Voids in the Cosmic Web as a probe of dark energy

    Directory of Open Access Journals (Sweden)

    B. Novosyadlyj

    2017-03-01

    Full Text Available The formation of large voids in the Cosmic Web from the initial adiabatic cosmological perturbations of space-time metric, density and velocity of matter is investigated in cosmological model with the dynamical dark energy accelerating expansion of the Universe. It is shown that the negative density perturbations with the initial radius of about 50 Mpc in comoving to the cosmological background coordinates and the amplitude corresponding to the r.m.s. temperature fluctuations of the cosmic microwave background lead to the formation of voids with the density contrast up to -0.9, maximal peculiar velocity about 400 km/s and the radius close to the initial one. An important feature of voids formation from the analyzed initial amplitudes and profiles is establishing the surrounding overdensity shell. We have shown that the ratio of the peculiar velocity in units of the Hubble flow to the density contrast in the central part of a void does not depend or weakly depends on the distance from the center of the void. It is also shown that this ratio is sensitive to the values of dark energy parameters and can be used to find them based on the observational data on mass density and peculiar velocities of galaxies in the voids.

  19. Measuring the Properties of Void Galaxies in Environmental COntext (ECO) using RESOLVE

    Science.gov (United States)

    Florez, Jonathan; Berlind, Andreas A.; Moffett, Amanda J.; Gonzalez, Roberto; Eckert, Kathleen D.; Kannappan, Sheila; Resolve

    2015-01-01

    We measure the environmental dependence of multiple galaxy properties inside the Environmental COntext survey focusing primarily on void galaxies for this project. We define void galaxies to be ~5% of galaxies having the lowest local density, where density is determined using the Nth nearest neighbor method. We examine the stellar mass, color, fractional stellar mass growth rate (FSMGR), fractional gas mass determined from a photometric gas fraction relation calibrated with the RESOLVE survey, and morphology distributions of the void galaxy population and compare them to those of galaxies in other large-scale structures (such as filaments or clusters). First, we show that our void galaxies typically have lower stellar masses than galaxies in denser environments, and they display the properties expected of a lower stellar mass population: they have late-types, are bluer, have higher FSMGR, and are more gas rich. Since color, star-formation, gas content, and morphology all correlate with stellar mass, we therefore move on to control for stellar mass and investigate the extent to which void galaxies are different at fixed mass. We show that void galaxies are indeed bluer and slightly more star forming at fixed stellar mass than galaxies in other environments. We also show that the ratio of blue early types to red early types is higher inside voids than in any other environment.

  20. Topology optimization with flexible void area

    DEFF Research Database (Denmark)

    Clausen, Anders; Aage, Niels; Sigmund, Ole

    2014-01-01

    This paper presents a methodology for including fixed-area flexible void domains into the minimum compliance topology optimization problem. As opposed to the standard passive elements approach of rigidly specifying void areas within the design domain, the suggested approach allows these areas...... to be flexibly reshaped and repositioned subject to penalization on their moments of inertia, the positions of their centers of mass, and their shapes. The flexible void areas are introduced through a second, discrete design variable field, using the same discretization as the standard field of continuous...... density variables. The formulation is based on a combined approach: The primary sub-problem is to minimize compliance, subject to a volume constraint, with a secondary sub-problem of minimizing the disturbance from the flexible void areas. The design update is performed iteratively between the two...

  1. Neutron Imaging Calibration to Measure Void Fraction

    Energy Technology Data Exchange (ETDEWEB)

    Geoghegan, Patrick J [ORNL; Bilheux, Hassina Z [ORNL; Sharma, Vishaldeep [ORNL; Fricke, Brian A [ORNL

    2015-01-01

    Void fraction is an intuitive parameter that describes the fraction of vapor in a two-phase flow. It appears as a key variable in most heat transfer and pressure drop correlations used to design evaporating and condensing heat exchangers, as well as determining charge inventory in refrigeration systems. Void fraction measurement is not straightforward, however, and assumptions on the invasiveness of the measuring technique must be made. Neutron radiography or neutron imaging has the potential to be a truly non-invasive void fraction measuring technique but has until recently only offered qualitative descriptions of two-phase flow, in terms of flow maldistributions, for example. This paper describes the calibration approach necessary to employ neutron imaging to measure steady-state void fraction. Experiments were conducted at the High Flux Isotope Reactor (HFIR) Cold Guide 1D neutron imaging facility at Oak Ridge National Laboratory (ORNL), Oak Ridge, TN, USA.

  2. Void growth in metals: Atomistic calculations

    Energy Technology Data Exchange (ETDEWEB)

    Traiviratana, Sirirat [Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093 (United States); Bringa, Eduardo M. [Materials Science Department, Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Benson, David J. [Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093 (United States); Meyers, Marc A. [Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093 (United States); NanoEngineering, University of California, San Diego, La Jolla, CA 92093 (United States)], E-mail: mameyers@ucsd.edu

    2008-09-15

    Molecular dynamics simulations in monocrystalline and bicrystalline copper were carried out with LAMMPS (Large-scale Atomic/Molecular Massively Parallel Simulator) to reveal void growth mechanisms. The specimens were subjected to tensile uniaxial strains; the results confirm that the emission of (shear) loops is the primary mechanism of void growth. It is observed that many of these shear loops develop along two slip planes (and not one, as previously thought), in a heretofore unidentified mechanism of cooperative growth. The emission of dislocations from voids is the first stage, and their reaction and interaction is the second stage. These loops, forming initially on different {l_brace}1 1 1{r_brace} planes, join at the intersection, if the Burgers vector of the dislocations is parallel to the intersection of two {l_brace}1 1 1{r_brace} planes: a <1 1 0> direction. Thus, the two dislocations cancel at the intersection and a biplanar shear loop is formed. The expansion of the loops and their cross slip leads to the severely work-hardened region surrounding a growing void. Calculations were carried out on voids with different sizes, and a size dependence of the stress threshold to emit dislocations was obtained by MD, in disagreement with the Gurson model which is scale independent. This disagreement is most marked for the nanometer sized voids. The scale dependence of the stress required to grow voids is interpreted in terms of the decreasing availability of optimally oriented shear planes and increased stress required to nucleate shear loops as the void size is reduced. The growth of voids simulated by MD is compared with the Cocks-Ashby constitutive model and significant agreement is found. The density of geometrically necessary dislocations as a function of void size is calculated based on the emission of shear loops and their outward propagation. Calculations are also carried out for a void at the interface between two grains to simulate polycrystalline

  3. Biofeedback therapy and dysfunctional voiding in children.

    Science.gov (United States)

    Duel, Barry P

    2003-04-01

    Dysfunctional voiding, a condition in which a neurologically intact child fails to relax the urinary sphincter during micturition, was first described in the 1970s. Clinically, these children have urinary incontinence and recurrent urinary tract infections. Biofeedback, through which the child is taught to relax the pelvic floor during voiding, has become an increasingly popular method of treatment. Many series, most retrospective, have shown biofeedback to be very effective in the treatment of this disorder.

  4. Post-void residual urine under 150 ml does not exclude voiding dysfunction in women

    DEFF Research Database (Denmark)

    Khayyami, Yasmine; Klarskov, Niels; Lose, Gunnar

    2016-01-01

    INTRODUCTION AND HYPOTHESIS: It has been claimed that post-void residual urine (PVR) below 150 ml rules out voiding dysfunction in women with stress urinary incontinence (SUI) and provides license to perform sling surgery. The cut-off of 150 ml seems arbitrary, not evidence-based, and so we sought....... CONCLUSIONS: Patients with voiding dysfunction often have normal PVR and so PVR incontinence surgery....

  5. Using Behavior Change to Reduce Child Lead Exposure in Resource-Poor Settings: A Formative Study

    Science.gov (United States)

    Feit, M. N.; Mathee, A.; Harpham, T.; Barnes, B. R.

    2014-01-01

    The objective of this formative research was to explore the acceptability and feasibility of changing housekeeping behaviors as a low-cost approach that may reduce childhood lead exposure in Johannesburg, South Africa. Using the Trials of Improved Practices (TIPs) methodology, modified housekeeping behaviors were negotiated with participants who…

  6. Steps in design, development and formative evaluation of obesity prevention-related behavior change trials

    OpenAIRE

    Cerin, E; Baranowski, J; Baranowski, T

    2009-01-01

    Abstract Obesity prevention interventions through dietary and physical activity change have generally not been effective. Limitations on possible program effectiveness are herein identified at every step in the mediating variable model, a generic conceptual framework for understanding how interventions may promote behavior change. To minimize these problems, and thereby enhance likely intervention effectiveness, four sequential types of formative studies are proposed: targeted behavior valida...

  7. Dynamic behavior of a social model for opinion formation.

    Science.gov (United States)

    Bordogna, Clelia M; Albano, Ezequiel V

    2007-12-01

    The dynamic behavior of a social group influenced by both a strong leader and the mass media, which is modeled according to the social impact theory, is studied under two situations: (i) The strong leader changes his/her state of opinion periodically while the mass media are not considered. In this case, the leader is capable of driving the group between a dynamically ordered state with a weak leader-group coupling (high-frequency regime) and a dynamically disordered state where the group follows the opinion of the leader (low-frequency regime). (ii) The mass-media change periodically their message and have to compete with a strong leader that keeps his/her state of opinion unchanged. In this case, the mass media require an amplitude threshold in order to overcome the influence of the leader and drive the system into a dynamically disordered state. The dynamic behavior characteristic of the studied social opinion model shares many features of physical systems that are relevant in the fields of statistical mechanics and condensed matter.

  8. Influence of void density on dislocation mechanisms of void shrinkage in nickel single crystal based on molecular dynamics simulation

    Science.gov (United States)

    Zhang, Yanqiu; Jiang, Shuyong; Zhu, Xiaoming; Zhao, Yanan

    2017-06-01

    Molecular dynamics (MD) simulations were performed to investigate influence of void density on dislocation mechanism of void shrinkage in nickel single crystal. The simulation results show that the higher void density can accelerate the yield of nickel single crystal. During the compression, all the dislocations are emitted toward the other side of the voids, which causes the atoms on the void surface to move into the voids and finally leads to the shrinkage of the voids. There exist six types of dislocations during void shrinkage of nickel single crystal, and the densities of all the six types of dislocations increase with the increase in the void density. The increase of Shockley partial dislocations enhances the slip ability of nickel single crystal, so the void size decreases with the increase in the void density at a constant stain.

  9. Enthalpy and void distributions in subchannels of PHWR fuel bundles

    Energy Technology Data Exchange (ETDEWEB)

    Park, J. W.; Choi, H.; Rhee, B. W. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1998-12-31

    Two different types of the CANDU fuel bundles have been modeled for the ASSERT-IV code subchannel analysis. From calculated values of mixture enthalpy and void fraction distribution in the fuel bundles, it is found that net buoyancy effect is pronounced in the central region of the DUPIC fuel bundle when compared with the standard CANDU fuel bundle. It is also found that the central region of the DUPIC fuel bundle can be cooled more efficiently than that of the standard fuel bundle. From the calculated mixture enthalpy distribution at the exit of the fuel channel, it is found that the mixture enthalpy and void fraction can be highest in the peripheral region of the DUPIC fuel bundle. On the other hand, the enthalpy and the void fraction were found to be highest in the central region of the standard CANDU fuel bundle at the exit of the fuel channel. This study shows that the subchannel analysis is very useful in assessing thermal behavior of the fuel bundle that could be used in CANDU reactors. 10 refs., 4 figs., 2 tabs. (Author)

  10. Behavior of Zirconium Sponge Formation in the Kroll Process

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Yong-Ik; Sohn, Ho-Sang [Kyungpook National University, Daegu (Korea, Republic of); Jung, Jae-Young [Research Institute of Industrial Science and Technology(RIST), Pohang (Korea, Republic of)

    2014-04-15

    The Kroll process of magnesium reduction of titanium tetrachloride is used for mass production of zirconium sponges. This study is conducted in a laboratory-scale reactor in order to develop a better understanding of the zirconium sponge formation mechanism in the Kroll reactor with respect to the reaction degrees and reaction time. The MgCl{sub 2} produced during the initial stage of the reaction does not sink into the molten magnesium, but remains on the surface of the molten magnesium. As a result, ZrCl{sub 4} feed reacts with the Mg exposed on the edge of the molten MgCl{sub 2} in the crucible. Therefore, the Zr particles produced at the later reaction stage descend into the molten magnesium at the crucible wall.

  11. Quality of life and self-esteem for children with urinary urge incontinence and voiding postponement.

    Science.gov (United States)

    Natale, N; Kuhn, S; Siemer, S; Stöckle, M; von Gontard, A

    2009-08-01

    Urge incontinence and voiding postponement are common subtypes of daytime wetting in children. We analyzed health related quality of life for children with urge incontinence and voiding postponement, and healthy controls at 2 centers. We examined a total of 49 consecutive children 5 to 13 years old who presented with urge incontinence (22) or voiding postponement (27), and 32 controls matched for age and sex. Health related and overall quality of life were measured with generic questionnaires, and self-esteem was measured with the Piers-Harris questionnaire. Health related quality of life was significantly reduced in parent rating but not in child rating in the incontinent vs control group (total mean parent score 73 vs 78, child 76 vs 76). Children with voiding postponement have the lowest health related quality of life. Overall quality of life was significantly reduced in children with incontinence, while self-esteem did not differ. Children with externalizing disorders generally have the lowest health related and overall quality of life. Health related and overall quality of life are useful constructs, and are reduced in children with daytime incontinence by parental rating. In comparison, children rate their quality of life as being higher. Quality of life is lowest with externalizing behavioral disorders, as in children with voiding postponement. Due to comorbid behavioral disturbances, children with voiding postponement often need additional assessment, counseling and treatment.

  12. 38 CFR 3.207 - Void or annulled marriage.

    Science.gov (United States)

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Void or annulled marriage... Void or annulled marriage. Proof that a marriage was void or has been annulled should consist of: (a... marriage void, together with such other evidence as may be required for a determination. (b) Annulled. A...

  13. Trampoline effect and the force field inside the void in complex plasma under microgravity conditions

    Energy Technology Data Exchange (ETDEWEB)

    Khrapak, S. A.; Kretschmer, M.; Zhdanov, S. K.; Thomas, H. M.; MOrfill, G. e.; Fortov, V. E.; Lipaev, A. M.; Molotkov, V. I.; Ivanov, A. I.; Turin, M. V.

    2005-07-01

    The PKE-Nefedov facility onboard the International Space Station (ISS),operational since March, 2'001, has enabled the study of complex (dusty) plasmas under microgravity conditions. A complex plasma is generated by introducing micron sized grains in a capacitively coupled rf discharge. The grains form a cloud inside the bulk of the discharge and can be easily visualized with the help of standard tools-laser illumination and video cameras. In most of the experiments under microgravity conditions the central region of the discharge is free of grains a so called void is formed. Due to recent theoretical advances, showing that the ion drag force can be more than a factor of ten larger than had traditionally been believed, void formation is now through to be a consequence of this (enhanced) interaction. The way this process works is the following: the ions drifting from the central region of a discharge to its walls and electrodes transfer their momentum to the grains pushing them out of the center. However, no direct experimental results on the origin of the void formation were reported so far. In this paper we report new results on the observation of a weak instability of the void-complex plasma interface observed at a relatively low gas pressure (p=12Pa). The instability leads to periodic injections of a relatively small number of particles into the void region (by analogy this effect is called trampoline effect), The trajectories of injected particles are analyzed providing information on the force field and potential energy distribution inside the void. For the relatively low neutral gas pressure used in the experiment a direct comparison with theory involving a model of the ion drag force in the collisionless regime is possible. Such a comparison yields good agreement, implying that we have observed the first experimental confirmation of the ion drag mechanism as being responsible for the void formation. (Author)

  14. CT measurements of SAP voids in concrete

    DEFF Research Database (Denmark)

    Laustsen, Sara; Bentz, Dale P.; Hasholt, Marianne Tange

    2010-01-01

    X-ray computed tomography (CT) scanning is used to determine the SAP void distribution in hardened concrete. Three different approaches are used to analyse a binary data set created from CT measurement. One approach classifies a cluster of connected, empty voxels (volumetric pixel of a 3D image......) as one void, whereas the other two approaches are able to classify a cluster of connected, empty voxels as a number of individual voids. Superabsorbent polymers (SAP) have been used to incorporate air into concrete. An advantage of using SAP is that it enables control of the amount and size...... to calculate the liquid absorption of the SAP within the fresh concrete. This estimated liquid absorption is in reasonable agreement with previous studies....

  15. Precision cosmology defeats void models for acceleration

    Science.gov (United States)

    Moss, Adam; Zibin, James P.; Scott, Douglas

    2011-05-01

    The suggestion that we occupy a privileged position near the center of a large, nonlinear, and nearly spherical void has recently attracted much attention as an alternative to dark energy. Putting aside the philosophical problems with this scenario, we perform the most complete and up-to-date comparison with cosmological data. We use supernovae and the full cosmic microwave background spectrum as the basis of our analysis. We also include constraints from radial baryonic acoustic oscillations, the local Hubble rate, age, big bang nucleosynthesis, the Compton y distortion, and for the first time include the local amplitude of matter fluctuations, σ8. These all paint a consistent picture in which voids are in severe tension with the data. In particular, void models predict a very low local Hubble rate, suffer from an “old age problem,” and predict much less local structure than is observed.

  16. Nonlocal plasticity effects on interaction of different size voids

    DEFF Research Database (Denmark)

    Tvergaard, Viggo; Niordson, Christian Frithiof

    2004-01-01

    A nonlocal elastic-plastic material model is used to show that the rate of void growth is significantly reduced when the voids are small enough to be comparable with a characteristic material length. For a very small void in the material between much larger voids the competition between an increa......A nonlocal elastic-plastic material model is used to show that the rate of void growth is significantly reduced when the voids are small enough to be comparable with a characteristic material length. For a very small void in the material between much larger voids the competition between...... an increased growth rate due to the stress concentrations around the larger voids and a reduced growth rate due to the nonlocal effects is studied. The analyses are based on an axisymmetric unit cell model with special boundary conditions, which allow for a relatively simple investigation of a full three...

  17. A reliability study on tin based lead free micro joint including intermetallic and void evolution

    Science.gov (United States)

    Feyissa, Frezer Assefa

    In microelectronics soldering to Cu pad lead to formation of two intermetallic structures in the solder -pad interface. The growth of these layers is accompanied by microscopic voids that usually cause reliability concern in the industry. Therefore it is important to understand factors that contribute for the growth of IMC using various combination of reflow time, Sn thickness and aging temperature. Systematic study was conducted on Cu-Sn system to investigate the formation and growth of intermetallic compound (IMC) as well as voiding evolution for different solder thicknesses. The growth of the Cu6Sn5 IMC layer was found to be increasing as the Sn thicknesses increase after reflow while the Cu3Sn layer were decreasing under same conditions. Also after reflow and aging more voiding were shown to occur in the thin solder than thicker one.

  18. Three-Dimensional Analysis of Voids in AM60B Magnesium Tensile Bars Using Computed Tomography Imagery

    Energy Technology Data Exchange (ETDEWEB)

    Waters, A M

    2001-05-01

    In an effort to increase automobile fuel efficiency as well as decrease the output of harmful greenhouse gases, the automotive industry has recently shown increased interest in cast light metals such as magnesium alloys in an effort to increase weight savings. Currently several magnesium alloys such as AZ91 and AM60B are being used in structural applications for automobiles. However, these magnesium alloys are not as well characterized as other commonly used structural metals such as aluminum. This dissertation presents a methodology to nondestructively quantify damage accumulation due to void behavior in three dimensions in die-cast magnesium AM60B tensile bars as a function of mechanical load. Computed tomography data was acquired after tensile bars were loaded up to and including failure, and analyzed to characterize void behavior as it relates to damage accumulation. Signal and image processing techniques were used along with a cluster labeling routine to nondestructively quantify damage parameters in three dimensions. Void analyses were performed including void volume distribution characterization, nearest neighbor distance calculations, shape parameters, and volumetric renderings of voids in the alloy. The processed CT data was used to generate input files for use in finite element simulations, both two- and three-dimensional. The void analyses revealed that the overwhelming source of failure in each tensile bar was a ring of porosity within each bar, possibly due to a solidification front inherent to the casting process. The measured damage parameters related to void nucleation, growth, and coalescence were shown to contribute significantly to total damage accumulation. Void volume distributions were characterized using a Weibull function, and the spatial distributions of voids were shown to be clustered. Two-dimensional finite element analyses of the tensile bars were used to fine-tune material damage models and a three-dimensional mesh of an extracted

  19. Halo abundances and shear in void models

    DEFF Research Database (Denmark)

    Alonso, David; García-Bellido, Juan; Haugbølle, Troels

    2012-01-01

    We study the non-linear gravitational collapse of dark matter into halos through numerical N-body simulations of Lemaitre-Tolman-Bondi void models. We extend the halo mass function formalism to these models in a consistent way. This extension not only compares well with the simulated data at all...

  20. URODYNAMIC EVALUATION OF VOIDING FUNCTION IN ...

    African Journals Online (AJOL)

    Objective The evaluation of voiding function in females with lower urinary tract symptoms (LUTS) with a special emphasis on the evaluation of storage function and the state of continence. Patients and Methods 176 patients were investigated for urinary incontinence-related problems at the Unit for Neuro-Urology and ...

  1. Voiding dysfunction in women following cesarean delivery

    Directory of Open Access Journals (Sweden)

    Ching-Chung Liang

    2015-12-01

    Conclusion: Our results showed that emergency cesarean delivery, prolonged operation time and postoperative analgesia are the main contributing factors of PVD after cesarean delivery. If urinary retention can be detected in time, transient PVD is not detrimental to urinary function and does not subsequently lead to voiding problems.

  2. The Metallicity of Void Dwarf Galaxies

    NARCIS (Netherlands)

    Kreckel, K.; Croxall, K.; Groves, B.; van de Weygaert, R.; Pogge, R. W.

    The current ΛCDM cosmological model predicts that galaxy evolution proceeds more slowly in lower density environments, suggesting that voids are a prime location to search for relatively pristine galaxies that are representative of the building blocks of early massive galaxies. To test the

  3. Voiding dysfunctions in children with mental retardation.

    Science.gov (United States)

    Yang, Pei-Yu; Meng, Nai-Hsin; Chou, Eric Chieh-lung

    2010-09-01

    This study aims to evaluate the voiding disorder and lower urinary tract symptoms in mentally retarded children. Fifty-one mentally retarded children (age 7.7 years) was assessed. A volunteer sample comprised of 36 typically developing children (age 6.4 years) served as the comparative group. All participants underwent uroflometric investigation, and residual urine was detected by sonography. Urological history including history of urinary tract infection, incontinence, frequency, and dysurea was collected. In addition, the mentally retarded group was classified according to IQ: severe mentally retarded group (IQ below 40) (n = 11), moderate mentally retarded group (IQ: 41 to 55) (n = 19), mild mentally retarded group (IQ: 56 to 70) (n = 21). Group comparisons were analyzed using Chi-square and Student's t-test. Of the 51 mentally retarded children, 18(35.2%) were found to have voiding dysfunction, which is significantly higher than the control group (8.3%). The incidence of urine incontinence and frequency is also significantly higher in the mentally retarded group. The comparison of the three mentally retarded subgroups showed that the severe mentally retarded group had the highest incidence of voiding dysfunction and urinary incontinence. Overall, the mentally retarded group had higher percentage of small bladder capacity. We concluded that mentally retarded children have a higher incidence of voiding dysfunction and incontinence than the control group. Early detection of voiding dysfunction in an objective, non-invasive manner is important in mentally retarded children, particularly those with severe cognitive impairment. © 2009 Wiley-Liss, Inc.

  4. Behavioral training for parents of retarded children: alternative formats based on instructional manuals.

    Science.gov (United States)

    Heifetz, L J

    1977-09-01

    A series of instructional manuals in behavior modification with retarded children was tested as a self-contained resource and as part of three larger training programs involving different amounts of professional assistance to parents: telephone consultations, training groups, training groups plus home visits. One hundred and sixty families were randomly assigned to the four training conditions or to a delayed-treatment control group. The 20-week treatment period emphasized the programming of self-help skills, but also provided an introduction to programming language skills and managing behavior problems. The manuals-alone format was as effective as the more expensive training formats in producing gains in children's self-help skills and fostering knowledge of behavioral principles in mothers. The two group-training formats produced more efforts at behavior-problem management, greater gains in knowledge of principles by fathers, and higher self-confidence as teachers. Telephone consultation was generally the least effective training format; the manuals-alone condition was surprisingly effective. Some implications of the results for future strategies of family intervention were discussed.

  5. Classroom Behavior of Participants with ADHD Compared with Peers: Influence of Teaching Format and Grade Level

    Science.gov (United States)

    Steiner, Naomi J.; Sheldrick, R. Chris; Frenette, Elizabeth C.; Rene, Kirsten M.; Perrin, Ellen C.

    2014-01-01

    Few studies examine the classroom behavior of children with attention deficit hyperactivity disorder (ADHD) in comparison with classroom peers and which teaching formats best support classroom engagement. Observations (N = 312) of second- and fourth-grade students with ADHD and their randomly selected classroom peers were conducted using a…

  6. A Formation Behavior for Large-Scale Micro-Robot Deployment

    Energy Technology Data Exchange (ETDEWEB)

    Dudenhoeffer, Donald Dean; Jones, Michael Paul

    2000-12-01

    Micro-robots will soon be available for deployment by the thousands. Consequently, controlling and coordinating a force this large to accomplish a prescribed task is of great interest. This paper describes a flexible architecture for modeling thousands of autonomous agents simultaneously. The agents’ behavior is based on a subsumption architecture in which individual behaviors are prioritized with respect to all others. The primary behavior explored in this work is a group formation behavior based on social potential fields (Reif and Wang 1999). This paper extends the social potential field model by introducing a neutral zone within which other behaviors may exhibit themselves. Previous work with social potential fields has been restricted to models of “perfect” autonomous agents. The paper evaluates the effect of social potential fields in the presence of agent death (failure) and imperfect sensory input.

  7. Risk management of low air void asphalt concrete mixtures.

    Science.gov (United States)

    2013-07-01

    Various forms of asphalt pavement distress, such as rutting, shoving and bleeding, can be attributed, in many cases, to low air voids in : the mixtures during production and placement. The occurrence of low air void contents during plant production m...

  8. Predator-induced fleeing behaviors in phytoplankton: a new mechanism for harmful algal bloom formation?

    Directory of Open Access Journals (Sweden)

    Elizabeth L Harvey

    Full Text Available In the plankton, heterotrophic microbes encounter and ingest phytoplankton prey, which effectively removes >50% of daily phytoplankton production in the ocean and influences global primary production and biochemical cycling rates. Factors such as size, shape, nutritional value, and presence of chemical deterrents are known to affect predation pressure. Effects of movement behaviors of either predator or prey on predation pressure, and particularly fleeing behaviors in phytoplankton are thus far unknown. Here, we quantified individual 3D movements, population distributions, and survival rates of the toxic phytoplankton species, Heterosigma akashiwo in response to a ciliate predator and predator-derived cues. We observed predator-induced defense behaviors previously unknown for phytoplankton. Modulation of individual phytoplankton movements during and after predator exposure resulted in an effective separation of predator and prey species. The strongest avoidance behaviors were observed when H. akashiwo co-occurred with an actively grazing predator. Predator-induced changes in phytoplankton movements resulted in a reduction in encounter rate and a 3-fold increase in net algal population growth rate. A spatially explicit population model predicted rapid phytoplankton bloom formation only when fleeing behaviors were incorporated. These model predictions reflected field observations of rapid H. akashiwo harmful algal bloom (HAB formation in the coastal ocean. Our results document a novel behavior in phytoplankton that can significantly reduce predation pressure and suggests a new mechanism for HAB formation. Phytoplankton behaviors that minimize predatory losses, maximize resource acquisition, and alter community composition and distribution patterns could have major implications for our understanding and predictive capacity of marine primary production and biochemical cycling rates.

  9. Predator-induced fleeing behaviors in phytoplankton: a new mechanism for harmful algal bloom formation?

    Science.gov (United States)

    Harvey, Elizabeth L; Menden-Deuer, Susanne

    2012-01-01

    In the plankton, heterotrophic microbes encounter and ingest phytoplankton prey, which effectively removes >50% of daily phytoplankton production in the ocean and influences global primary production and biochemical cycling rates. Factors such as size, shape, nutritional value, and presence of chemical deterrents are known to affect predation pressure. Effects of movement behaviors of either predator or prey on predation pressure, and particularly fleeing behaviors in phytoplankton are thus far unknown. Here, we quantified individual 3D movements, population distributions, and survival rates of the toxic phytoplankton species, Heterosigma akashiwo in response to a ciliate predator and predator-derived cues. We observed predator-induced defense behaviors previously unknown for phytoplankton. Modulation of individual phytoplankton movements during and after predator exposure resulted in an effective separation of predator and prey species. The strongest avoidance behaviors were observed when H. akashiwo co-occurred with an actively grazing predator. Predator-induced changes in phytoplankton movements resulted in a reduction in encounter rate and a 3-fold increase in net algal population growth rate. A spatially explicit population model predicted rapid phytoplankton bloom formation only when fleeing behaviors were incorporated. These model predictions reflected field observations of rapid H. akashiwo harmful algal bloom (HAB) formation in the coastal ocean. Our results document a novel behavior in phytoplankton that can significantly reduce predation pressure and suggests a new mechanism for HAB formation. Phytoplankton behaviors that minimize predatory losses, maximize resource acquisition, and alter community composition and distribution patterns could have major implications for our understanding and predictive capacity of marine primary production and biochemical cycling rates.

  10. Atomic level simulations of interaction between edge dislocations and irradiation induced ellipsoidal voids in alpha-iron

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Bida [Department of Mechanics, Huazhong University of Science and Technology, Wuhan 430074 (China); Huang, Minsheng, E-mail: mshuang@hust.edu.cn [Department of Mechanics, Huazhong University of Science and Technology, Wuhan 430074 (China); Hubei Key Laboratory of Engineering Structural Analysis and Safety Assessment, Luoyu Road 1037, Wuhan 430074 (China); Li, Zhenhuan [Department of Mechanics, Huazhong University of Science and Technology, Wuhan 430074 (China); Hubei Key Laboratory of Engineering Structural Analysis and Safety Assessment, Luoyu Road 1037, Wuhan 430074 (China)

    2017-04-15

    High concentrations of vacancies tend to be formed inside the metal materials under irradiation, and then accumulate and cluster together gradually to promote the formation of nanovoids. Generally, these voids act as obstacles for dislocation glide and thereby change/degrade the mechanical behavior of irradiated materials. In this work, the interaction between ellipsoidal nanovoids with edge dislocations in alpha-iron has been studied by atomic simulations. The results illuminate that the ellipsoidal void’s semi-major axis on the slip plane and parallel to the dislocation line is the dominant factor controlling the obstacle strength of ellipsoidal nanovoids. Two other semi-major axes, which are perpendicular to the glide plane and parallel to the Burgers vector, respectively, can also influence the critical resolved shear stress (CRSS) for dislocation shearing the ellipsoidal void. The intrinsic atomic mechanisms controlling above phenomena, such as nanovoid-geometry spatial constraint and nanovoid-surface curvature on dislocation evolution, have been discussed carefully. The classical continuum model has been amended to describe the dislocation-ellipsoidal nanovoid interaction base on current results. In addition, the influence of temperature on the CRSS of ellipsoidal nanovoids has also been investigated.

  11. Development of AN Intensity Based Fiber Optic Sensor and Predictive Models for in Situ Void Detection during Polymer Composite Cure.

    Science.gov (United States)

    Klosterman, Donald A.

    ellipsometric calibration was deemed inaccurate due to cure shrinkage effects and thin film cure behavior. The calibration obtained with the model was successfully used with the model to predict the signal for various cure cycles of the neat 3501-6 resin. For real time void monitoring, the use of the sensor model was demonstrated under experimental conditions. Finally, a simplified method of predicting the sensor signal was developed and verified for the cure of neat, void free 3501-6 resin.

  12. An example from the Talchir Formation, Satpura Gond

    Indian Academy of Sciences (India)

    wedge Structure: Contraction of sediment piles due to frosting often leads to formation of cracks that appear as upward widening wedge- shaped voids in profile. Following melting of ice, these voids are filled with sediments representing ice-wedge ...

  13. Strong coupling in porphyrin J-aggregate excitons and plasmons in nano-void arrays

    Science.gov (United States)

    Ferdele, Stefano; Jose, Bincy; Foster, Robert; Keyes, Tia E.; Rice, James H.

    2017-10-01

    Active plasmonic nano-void arrays made through colloidal lithography (a cost effective and rapid process) potentially offers opportunities for scalable device design. In this work we demonstrate strong coupling between Bragg-like quadrupole surface plasmon modes in nano-void substrate designs with Frankel excitons in a molecular J-aggregate layer though angular tuning. The enhanced exciton-plasmon coupling creates a Fano like line shape in the differential reflection spectra associated with the formation of new hybrid states, leading to anti-crossing of the upper and lower polaritons with a Rabi frequency of 120 meV.

  14. Voids as alternatives to dark energy and the propagation of γ rays through the universe.

    Science.gov (United States)

    DeLavallaz, Arnaud; Fairbairn, Malcolm

    2012-04-27

    We test the opacity of a void universe to TeV energy γ rays having obtained the extragalactic background light in that universe using a simple model and the observed constraints on the star formation rate history. We find that the void universe has significantly more opacity than a Λ cold dark matter universe, putting it at odds with observations of BL-Lac objects. We argue that while this method of distinguishing between the two cosmologies contains uncertainties, it circumvents any debates over fine-tuning.

  15. Effect of Contact Conditions on Void Coalescence at Low Stress Triaxiality Shearing

    DEFF Research Database (Denmark)

    Dahl, Jonas; Nielsen, Kim Lau; Tvergaard, Viggo

    2012-01-01

    to zero stress triaxiality. Furthermore, it is shown that accounting for friction at the void surface strongly postpones the onset of coalescence, hence, increasing the overall material ductility. The changes in overall material behavior are here presented for a wide range of initial material and loading...

  16. Plasticity size effects in voided crystals

    DEFF Research Database (Denmark)

    Hussein, M.I.; Borg, Ulrik; Niordson, Christian Frithiof

    2008-01-01

    The shear and equi-biaxial straining responses of periodic voided single crystals are analysed using discrete dislocation plasticity and a continuum strain gradient crystal plasticity theory. In the discrete dislocation formulation, the dislocations are all of edge character and are modelled...... between predictions of the two formulations for all crystal types and void volume fractions considered when the material length scale in the non-local plasticity model is chosen to be 0.325 mu m (about 10 times the slip plane spacing in the discrete dislocation models)....... as line singularities in an elastic material. The lattice resistance to dislocation motion, dislocation nucleation, dislocation interaction with obstacles and annihilation are incorporated through a set of constitutive rules. Over the range of length scales investigated, both the discrete dislocation...

  17. Plasticity size effects in voided crystals

    DEFF Research Database (Denmark)

    Hussein, M. I.; Borg, Ulrik; Niordson, Christian Frithiof

    The shear and equi-biaxial straining responses of periodic voided single crystals are analysed using discrete dislocation plasticity and a continuum strain gradient crystal plasticity theory. In the discrete dislocation formulation the dislocations are all of edge character and are modelled as line...... predictions of the two formulations for all crystal types and void volume fractions considered when the material length scale in the non-local plasticity model chosen to be $0.325\\mu m$ (around ten times the slip plane spacing in the discrete dislocation models)....... singularities in an elastic material. The lattice resistance to dislocation motion, dislocation nucleation, dislocation interaction with obstacles and annihilation are incorporated through a set of constitutive rules. Over the range of length scales investigated, both the discrete dislocation and strain...

  18. Influence of ageing, inclusions and voids on ductile fracture ...

    Indian Academy of Sciences (India)

    Unknown

    increases (Cabot and Burlion 1996). Voids that initiate at particular inclusions can grow to a uniform size consi- derably in excess of the average particle spacing without the interference of adjacent particles, or the initiation of additional voids at these adjacent particles. 3.3 Void coalescence and the effect of small inclusions.

  19. The Cosmically Depressed : Life, Sociology and Identity of Voids

    NARCIS (Netherlands)

    van de Weygaert, R.; Platen, E.; Tigrak, E.; Hidding, J.; van der Hulst, J. M.; Aragon-Calvo, M. A.; Stanonik, K.; van Gorkom, J. H.; VerdesMontenegro, L; DelOlmo, A; Sulentic, J

    2010-01-01

    In this contribution we review and discuss several aspects of Cosmic Voids, as a background for our void galaxy project (accompanying paper by Stanonik et al.). Voids are a major component of the large scale distribution of matter and galaxies in the Universe. Following a sketch of the general

  20. Effect of void cluster on ductile failure evolution

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    2016-01-01

    , are the same for the clusters and the single void. In the comparison it is essential that local void coalescence inside the clusters is accounted for, since this allows for considering the rate of growth of the single larger void that results from coalescence in the cluster. To obtain a parametric...

  1. Precision cosmology defeats void models for acceleration

    OpenAIRE

    Moss, Adam; Zibin, James P.; Scott, Douglas

    2010-01-01

    The suggestion that we occupy a privileged position near the centre of a large, nonlinear, and nearly spherical void has recently attracted much attention as an alternative to dark energy. Putting aside the philosophical problems with this scenario, we perform the most complete and up-to-date comparison with cosmological data. We use supernovae and the full cosmic microwave background spectrum as the basis of our analysis. We also include constraints from radial baryonic acoustic oscillations...

  2. Avrami behavior of magnetite nanoparticles formation in co-precipitation process

    Directory of Open Access Journals (Sweden)

    Ahmadi R.

    2011-01-01

    Full Text Available In this work, magnetite nanoparticles (mean particle size about 20 nm were synthesized via coprecipitation method. In order to investigate the kinetics of nanoparticle formation, variation in the amount of reactants within the process was measured using pH-meter and atomic absorption spectroscopy (AAS instruments. Results show that nanoparticle formation behavior can be described by Avrami equations. Transmission electron microscopy (TEM and X-ray diffraction (XRD were performed to study the chemical and morphological characterization of nanoparticles. Some simplifying assumptions were employed for estimating the nucleation and growth rate of magnetite nanoparticles.

  3. Dwarf Galaxies in the Nearby Lynx-Cancer Void: Photometry, Colours and Ages

    Science.gov (United States)

    Pustilnik, Simon; Kniazev, Alexei; Lyamina, Yulia; Tepliakova, Arina

    The nearby Lynx-Cancer void is a good laboratory to study the effect of very rarefied environment on the evolution of the least massive dwarf galaxies. A recently compiled sample of this void's galaxies includes about one hundred objects with MB in the range -12 to -18 mag. Good quality images are available in the SDSS database for ˜80% of the sample. Their u, g, r, i, z photometry allows one to derive galaxy stellar mass (and, incorporating HI data, gas mass-fraction) and ages of visible stellar populations, and hence, the epoch of their formation (first SF episode). We present the first photometric results of the ongoing study of the Lynx-Cancer void.

  4. Influence of the austenitic stainless steel microstructure on the void swelling under ion irradiation

    Directory of Open Access Journals (Sweden)

    Rouxel Baptiste

    2016-01-01

    Full Text Available To understand the role of different metallurgical parameters on the void formation mechanisms, various austenitic stainless steels were elaborated and irradiated with heavy ions. Two alloys, in several metallurgical conditions (15Cr/15Ni–Ti and 15Cr/25Ni–Ti, were irradiated in the JANNUS-Saclay facility at 600 °C with 2 MeV Fe2+ ions up to 150 dpa. Resulting microstructures were observed by Transmission Electron Microscopy (TEM. Different effects on void swelling are highlighted. Only the pre-aged samples, which were consequently solute and especially titanium depleted, show cavities. The nickel-enriched matrix shows more voids with a smaller size. Finally, the presence of nano-precipitates combined with a dense dislocation network decreases strongly the number of cavities.

  5. Near‐surface void detection using a seismic landstreamer and horizontal velocity and attenuation tomography

    Science.gov (United States)

    Buckley, Sean F.; Lane, John W.

    2012-01-01

    The detection and characterization of subsurface voids plays an important role in the study of karst formations and clandestine tunnels. Horizontal velocity and attenuation tomography (HVAT) using offset‐fan shooting and a towed seismic land streamer is a simple, rapid, minimally invasive method that shows promise for detecting near‐surface voids and providing information on the orientation of linear voids. HVAT surveys were conducted over a known subsurface steam tunnel on the University of Connecticut Depot Campus, Storrs, Connecticut. First‐arrival travel‐time and amplitude data were used to produce two‐dimensional (2D) horizontal (map view) velocity and attenuation tomograms. In addition, attenuation tomograms were produced based on normalized total trace energy (TTE). Both the velocity and TTE attenuation tomograms depict an anomaly consistent with the location and orientation of the known tunnel; the TTE method, however, requires significantly less processing time, and therefore may provide a path forward to semi‐automated, near real‐time detection of near‐surface voids. Further study is needed to assess the utility of the HVAT method to detect deeper voids and the effects of a more complex geology on HVAT results.

  6. 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).

  7. Void growth and coalescence in metals deformed at elevated temperature

    DEFF Research Database (Denmark)

    Klöcker, H.; Tvergaard, Viggo

    2000-01-01

    For metals deformed at elevated temperatures the growth of voids to coalescence is studied numerically. The voids are assumed to be present from the beginning of deformation, and the rate of deformation considered is so high that void growth is dominated by power law creep of the material, without...... voids. The focus of the study is on various relatively high stress triaxialties. In order to represent the results in terms of a porous ductile material model a set of constitutive relations are used, which have been proposed for void growth in a material undergoing power law creep....

  8. On the asymptotic behavior of a boltzmann-type price formation model

    KAUST Repository

    Burger, Martin

    2014-01-01

    In this paper we study the asymptotic behavior of a Boltzmann-type price formation model, which describes the trading dynamics in a financial market. In many of these markets trading happens at high frequencies and low transaction costs. This observation motivates the study of the limit as the number of transactions k tends to infinity, the transaction cost a to zero and ka=const. Furthermore we illustrate the price dynamics with numerical simulations © 2014 International Press.

  9. Effect of stress-triaxiality on void growth in dynamic fracture of metals: a molecular dynamics study

    Energy Technology Data Exchange (ETDEWEB)

    Seppala, E T; Belak, J; Rudd, R E

    2003-10-07

    The effect of stress-triaxiality on growth of a void in a three dimensional single-crystal face-centered-cubic (FCC) lattice has been studied. Molecular dynamics (MD) simulations using an embedded-atom (EAM) potential for copper have been performed at room temperature and using strain controlling with high strain rates ranging from 10{sup 7}/sec to 10{sup 10}/sec. Strain-rates of these magnitudes can be studied experimentally, e.g. using shock waves induced by laser ablation. Void growth has been simulated in three different conditions, namely uniaxial, biaxial, and triaxial expansion. The response of the system in the three cases have been compared in terms of the void growth rate, the detailed void shape evolution, and the stress-strain behavior including the development of plastic strain. Also macroscopic observables as plastic work and porosity have been computed from the atomistic level. The stress thresholds for void growth are found to be comparable with spall strength values determined by dynamic fracture experiments. The conventional macroscopic assumption that the mean plastic strain results from the growth of the void is validated. The evolution of the system in the uniaxial case is found to exhibit four different regimes: elastic expansion; plastic yielding, when the mean stress is nearly constant, but the stress-triaxiality increases rapidly together with exponential growth of the void; saturation of the stress-triaxiality; and finally the failure.

  10. Void Coalescence Processes Quantified through Atomistic and Multiscale Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Rudd, R E; Seppala, E T; Dupuy, L M; Belak, J

    2005-12-31

    Simulation of ductile fracture at the atomic scale reveals many aspects of the fracture process including specific mechanisms associated with void nucleation and growth as a precursor to fracture and the plastic deformation of the material surrounding the voids and cracks. Recently we have studied void coalescence in ductile metals using large-scale atomistic and continuum simulations. Here we review that work and present some related investigations. The atomistic simulations involve three-dimensional strain-controlled multi-million atom molecular dynamics simulations of copper. The correlated growth of two voids during the coalescence process leading to fracture is investigated, both in terms of its onset and the ensuing dynamical interactions. Void interactions are quantified through the rate of reduction of the distance between the voids, through the correlated directional growth of the voids, and through correlated shape evolution of the voids. The critical inter-void ligament distance marking the onset of coalescence is shown to be approximately one void radius based on the quantification measurements used, independent of the initial separation distance between the voids and the strain-rate of the expansion of the system. No pronounced shear flow is found in the coalescence process.

  11. Parental Background and Union Formation Behavior of Native Born Individuals in Sweden with a Foreign Background

    Directory of Open Access Journals (Sweden)

    Aycan Çelikaksoy

    2014-06-01

    Full Text Available Social cohesion in destination countries is an increasingly important issue due to the multiethnic structures in these countries and due to ongoing international migration. Union formation of individuals across different backgrounds can be seen as an indicator of social cohesion. However, this phenomenon is important not only in the case of first generation migrants but also for their descendants. Thus, this paper analyzes the determinants of intergroup union formation patterns of the native born individuals with a foreign background focusing on the role of parental background in addition to individual as well as marriage market characteristics. High quality data at the individual level, from Statistics Sweden, for the whole population of interest is utilized. The results indicate that parental composition is an important determinant of union formation behavior. Furthermore, there are gender specific pathways of the parental background effects.

  12. Applying Trauma-Focused Cognitive-Behavioral Therapy in Group Format.

    Science.gov (United States)

    Deblinger, Esther; Pollio, Elisabeth; Dorsey, Shannon

    2016-02-01

    Trauma-focused cognitive-behavioral therapy (TF-CBT), a well-established, evidence-based treatment for children who have experienced trauma, has been increasingly utilized in a group format. Group therapy formats are appealing because they can be highly effective and have the potential to reach larger numbers of clients. Moreover, TF-CBT group delivery may be particularly valuable in reducing the feelings of shame, isolation, and stigma experienced by youth and their caregivers in the aftermath of traumatic experiences. This article reviews the group TF-CBT research, discusses the therapeutic benefits of TF-CBT therapy groups, and provides clinical and logistical guidance for implementing TF-CBT in group format, including a session-by-session protocol. Future directions for research and clinical work in this area are also discussed. © The Author(s) 2015.

  13. Voiding dysfunction in children aged five to 15 years

    Directory of Open Access Journals (Sweden)

    Karaklajić Dragana

    2004-01-01

    Full Text Available Voiding dysfunction in children was analyzed in 91 patients in a period from January 1st to October 1st 1998. Most of the patients had functional voiding disorder (92.31%, and only 7.69% manifested monosymptomatic night enuresis. The number of girls was bigger in the group of patients with voiding dysfunction while the boys were predominant in the group with mono-symptomatic nocturnal enuresis. More than a half of children with functional voiding disorder had repeated urinal infections (58.23%, incontinence (93.49%, need for urgent voiding (68.13%, and vesicoureteral reflux (47.61%. The most common type of voiding dysfunction was urge syndrome/urge incontinence. The incidence of dysfunctional voiding disorder was more often in children with scaring changes of kidney which were diagnosed by static scintigraphy.

  14. Recurrent urinary tract infection and functional voiding disorders.

    Science.gov (United States)

    Ramamurthy, H Ravi; Kanitkar, Madhuri

    2008-08-01

    This study was carried out to determine the association of recurrent urinary tract infections with functional voiding disorders. Sixty eight children with suspected functional voiding disorders were prospectively evaluated clinically and by non-invasive urodynamics. Invasive urodynamics were carried out when indicated. Group I comprised 34 children with symptoms suggestive of functional voiding disorders and recurrent urinary tract infections (mean age 6.3+/-2 yr) and Group II comprised 34 children with symptoms suggestive of functional voiding disorders without recurrent urinary tract infections (mean age 6.7+/-2 yr). The underlying bladder abnormalities in Groups I and II were detrusor instability in 22 (64.7%) and 30 (88.2%), respectively (P>0.05) and dysynergic voiding in 10 (29.4%), and 1 (2.9%), respectively (P<0.05). Children with recurrent urinary tract infections are more likely to have a dysynergic voiding pattern than children presenting with other symptoms of functional voiding disorders.

  15. Microvoid formation and strain hardening in highly cross-linked polymer networks.

    Science.gov (United States)

    Mukherji, Debashish; Abrams, Cameron F

    2008-11-01

    Using molecular dynamics simulations of a generic model, we observe strain hardening in highly cross-linked polymer glasses under tensile deformation. We show that formation of microvoids, without bond breaking, constitutes the microscopic origins of strain hardening. A well-defined functional form is observed for the void size distribution that is consistent with voids in dense equilibrium Lennard-Jones particle packings, independent of strain. Microvoid-based strain hardening is not observed in a separate model with tetrahedral bond angle constraints, indicating that flexible cross-linkers are the key factor in the development of strain hardening behavior.

  16. Morphology-Induced Collective Behaviors: Dynamic Pattern Formation in Water-Floating Elements

    Science.gov (United States)

    Nakajima, Kohei; Ngouabeu, Aubery Marchel Tientcheu; Miyashita, Shuhei; Göldi, Maurice; Füchslin, Rudolf Marcel; Pfeifer, Rolf

    2012-01-01

    Complex systems involving many interacting elements often organize into patterns. Two types of pattern formation can be distinguished, static and dynamic. Static pattern formation means that the resulting structure constitutes a thermodynamic equilibrium whose pattern formation can be understood in terms of the minimization of free energy, while dynamic pattern formation indicates that the system is permanently dissipating energy and not in equilibrium. In this paper, we report experimental results showing that the morphology of elements plays a significant role in dynamic pattern formation. We prepared three different shapes of elements (circles, squares, and triangles) floating in a water-filled container, in which each of the shapes has two types: active elements that were capable of self-agitation with vibration motors, and passive elements that were mere floating tiles. The system was purely decentralized: that is, elements interacted locally, and subsequently elicited global patterns in a process called self-organized segregation. We showed that, according to the morphology of the selected elements, a different type of segregation occurs. Also, we quantitatively characterized both the local interaction regime and the resulting global behavior for each type of segregation by means of information theoretic quantities, and showed the difference for each case in detail, while offering speculation on the mechanism causing this phenomenon. PMID:22715370

  17. Distinct migratory behaviors of striosome and matrix cells underlying the mosaic formation in the developing striatum.

    Science.gov (United States)

    Hagimoto, Kazuya; Takami, Saki; Murakami, Fujio; Tanabe, Yasuto

    2017-03-01

    The striatum, the largest nucleus of the basal ganglia controlling motor and cognitive functions, can be characterized by a labyrinthine mosaic organization of striosome/matrix compartments. It is unclear how striosome/matrix mosaic formation is spatially and temporally controlled at the cellular level during striatal development. Here, by combining in vivo electroporation and brain slice cultures, we set up a prospective experimental system in which we differentially labeled striosome and matrix cells from the time of birth and followed their distributions and migratory behaviors. Our results showed that, at an initial stage of striosome/matrix mosaic formation, striosome cells were mostly stationary, whereas matrix cells actively migrated in multiple directions regardless of the presence of striosome cells. The mostly stationary striosome cells were still able to associate to form patchy clusters via attractive interactions. Our results suggest that the restricted migratory capability of striosome cells may allow them to cluster together only when they happen to be located in close proximity to each other and are not separated by actively migrating matrix cells. The way in which the mutidirectionally migrating matrix cells intermingle with the mostly stationary striosome cells may therefore determine the topographic features of striosomes. At later stages, the actively migrating matrix cells began to repulse the patchy clusters of striosomes, presumably enhancing the striosome cluster formation and the segregation and eventual formation of dichotomous homogeneous striosome/matrix compartments. Overall, our study reveals temporally distinct migratory behaviors of striosome/matrix cells, which may underlie the sequential steps of mosaic formation in the developing striatum. J. Comp. Neurol. 525:794-817, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  18. Tensor anisotropy as a tracer of cosmic voids

    Science.gov (United States)

    Bustamante, Sebastian; Forero-Romero, Jaime E.

    2015-10-01

    We present a new method to find voids in cosmological simulations based on the tidal and the velocity shear tensors definitions of the cosmic web. We use the fractional anisotropy (FA) computed from the eigenvalues of each web scheme as a void tracer. We identify voids using a watershed transform based on the local minima of the FA field without making any assumption on the shape or structure of the voids. We test the method on the Bolshoi simulation and report on the abundance and radial averaged profiles for the density, velocity and FA. We find that voids in the velocity shear web are smaller than voids in the tidal web, with a particular overabundance of very small voids in the inner region of filaments/sheets. We classify voids as subcompensated/overcompensated depending on the absence/presence of an overdense matter ridge in their density profile, finding that close to 65 and 35 per cent of the total population are classified into each category, respectively. Finally, we find evidence for the existence of universal profiles from the radially averaged profiles for density, velocity and FA. This requires that the radial coordinate is normalized to the effective radius of each void. Put together, all these results show that the FA is a reliable tracer for voids, which can be used in complementarity to other existing methods and tracers.

  19. Abnormal voiding parameters in children with severe idiopathic constipation.

    Science.gov (United States)

    Chung, K L Y; Chao, N S Y; Liu, C S W; Tang, P M Y; Liu, K K W; Leung, M W Y

    2014-07-01

    It is suggested that idiopathic constipation may associate with abnormal voiding parameters. In this study, we investigate the voiding parameters in children with constipation. Since 2010, seventeen consecutive children (12 boys, 5 girls) aged 5-17 (median = 14) with significant constipation according to Rome III criteria and who were not responding to conventional treatment (diet, laxatives & bowel training) for over 6 months were recruited. The rectal diameter (RD) was measured by transpubic ultrasonography (USG), RD >3.5 cm was considered as dilated. Each patient had uroflow measurement and bladder USG done to measure the maximal flow rate (Vmax), voided volume (VV), and post-void residual urine (PVR). Abnormal voiding parameters were defined as Vmax 150% of age-adjusted expected bladder capacity (EBC) and/or PVR >20 ml. Rectal diameter ranged from 1.7 to 8.2 cm (median = 3 cm) and was abnormally dilated in eight children. Vmax was normal in all children (median = 23.7 ml/sec). Voided volume ranged from 30 to 289% of EBC and was abnormal in six children (35.5%). Post-void residual urine varied from 0 to 85 ml and was abnormal in six (35.5 %) children. Three children (17.6 %) had both abnormal VV and PVR. On the whole, the prevalence of abnormal voiding parameters in constipated children was 52.9 %. Mean RD in normal and abnormal parameters groups was 2.8 and 4.7 cm, respectively. Rectal dilation was associated with abnormal voiding parameters (p = 0.015). Abnormal voiding parameters including voided volume and post-void residual urine are prevalent in constipated children. Dilated rectum is associated with abnormal voiding parameters.

  20. Baryon effects on void statistics in the EAGLE simulation

    Science.gov (United States)

    Paillas, Enrique; Lagos, Claudia D. P.; Padilla, Nelson; Tissera, Patricia; Helly, John; Schaller, Matthieu

    2017-10-01

    Cosmic voids are promising tools for cosmological tests due to their sensitivity to dark energy, modified gravity and alternative cosmological scenarios. Most previous studies in the literature of void properties use cosmological N-body simulations of dark matter (DM) particles that ignore the potential effect of baryonic physics. Using a spherical underdensity finder, we analyse voids using the mass field and subhalo tracers in the Evolution and Assembly of Galaxies and their Environment (EAGLE) simulations, which follow the evolution of galaxies in a Λ cold dark matter universe with state-of-the-art subgrid models for baryonic processes in a (100 cMpc)3 volume. We study the effect of baryons on void statistics by comparing results with DM-only simulations that use the same initial conditions as EAGLE. When identifying voids in the mass field, we find that a DM-only simulation produces 24 per cent more voids than a hydrodynamical one due to the action of galaxy feedback polluting void regions with hot gas, specially for small voids with rvoid ≤ 10 Mpc. We find that the way in which galaxy tracers are selected has a strong impact on the inferred void properties. Voids identified using galaxies selected by their stellar mass are larger and have cuspier density profiles than those identified by galaxies selected by their total mass. Overall, baryons have minimal effects on void statistics, as void properties are well captured by DM-only simulations, but it is important to account for how galaxies populate DM haloes to estimate the observational effect of different cosmological models on the statistics of voids.

  1. The effect of voide size on the detonation pressure of emulsion explosives.

    Science.gov (United States)

    Hirosaki, Yoshikazu; Murata, Kenji; Kato, Yukio; Itoh, Shigeru

    2001-06-01

    Ammonium nitrate-based emulsion explosive show non-ideal detonation behavior. Voids included in the emulsion explosives affect the non-idealdetonation behavior. The effects of voide size on the detonation pressure of emulsion explosives were studied experimentally. Detonation pressure was measured for the emulsion explosives sensitized with resin balloons of five different size ranging from 0.05mm to 2.42mm in average diameter, using PVDF pressure sensor. Pressure profile of emulsion explosives containing resin balloon of 0.05mm in average diamater shows von Neumann spike and pressure decay in reaction zone followed by Taylor wave. Pressure profile of emulsion explosive containing larger balloons present gradual pressure rise in detonation front due to front curvature and front perturvation caused by large voids. The comparison between the measured detonation pressure and calculated detonation pressure indicates that the fraction of ammonium nitrate reacted in reaction zone is higher than 80containing resin balloons of 0.05mm in diameter, and as low as 302.42mm in diameter. It was shown that reaction zone length is strongly affected by void size.

  2. Formation of Molecular Networks: Tailored Quantum Boxes and Behavior of Adsorbed CO in Them

    Science.gov (United States)

    Wyrick, Jon; Sun, Dezheng; Kim, Dae-Ho; Cheng, Zhihai; Lu, Wenhao; Zhu, Yeming; Luo, Miaomiao; Kim, Yong Su; Rotenberg, Eli; Kim, Kwangmoo; Einstein, T. L.; Bartels, Ludwig

    2011-03-01

    We show that the behavior of CO adsorbed into the pores of large regular networks on Cu(111) is significantly affected by their nano-scale lateral confinement and that formation of the networks themselves is directed by the Shockley surface state. Saturation coverages of CO are found to exhibit persistent dislocation lines; at lower coverages their mobility increases. Individual CO within the pores titrate the surface state, providing crucial information for understanding formation of the network as a result of optimization of the number N of electrons bound within each pore. Determination of N is based on quinone-coverage-dependent UPS data and an analysis of states of particles in a pore-shaped box (verified by CO's titration); a wide range of possible pore shapes and sizes has been considered. Work at UCR supported by NSF CHE 07-49949; at UMD by NSF CHE 07-50334 & UMD NSF-MRSEC DMR 05-20471.

  3. Collective Behavior of Chiral Active Matter: Pattern Formation and Enhanced Flocking

    Science.gov (United States)

    Liebchen, Benno; Levis, Demian

    2017-08-01

    We generalize the Vicsek model to describe the collective behavior of polar circle swimmers with local alignment interactions. While the phase transition leading to collective motion in 2D (flocking) occurs at the same interaction to noise ratio as for linear swimmers, as we show, circular motion enhances the polarization in the ordered phase (enhanced flocking) and induces secondary instabilities leading to structure formation. Slow rotations promote macroscopic droplets with late time sizes proportional to the system size (indicating phase separation) whereas fast rotations generate patterns consisting of phase synchronized microflocks with a controllable characteristic size proportional to the average single-particle swimming radius. Our results defy the viewpoint that monofrequent rotations form a vapid extension of the Vicsek model and establish a generic route to pattern formation in chiral active matter with possible applications for understanding and designing rotating microflocks.

  4. The association of age of toilet training and dysfunctional voiding.

    Science.gov (United States)

    Hodges, Steve J; Richards, Kyle A; Gorbachinsky, Ilya; Krane, L Spencer

    2014-01-01

    To determine whether age of toilet training is associated with dysfunctional voiding in children. We compared patients referred to the urologic clinics for voiding dysfunction with age-matched controls without urinary complaints. Characteristics including age and reason for toilet training, method of training, and encopresis or constipation were compared between both groups. Initiation of toilet training prior to 24 months and later than 36 months of age were associated with dysfunctional voiding. However, dysfunctional voiding due to late toilet training was also associated with constipation. Dysfunctional voiding may be due to delayed emptying of the bowel and bladder by children. The symptoms of dysfunctional voiding are more common when toilet training early, as immature children may be less likely to empty in a timely manner, or when training late due to (or in association with) constipation.

  5. Steps in the design, development and formative evaluation of obesity prevention-related behavior change trials

    Directory of Open Access Journals (Sweden)

    Baranowski Janice

    2009-01-01

    Full Text Available Abstract Obesity prevention interventions through dietary and physical activity change have generally not been effective. Limitations on possible program effectiveness are herein identified at every step in the mediating variable model, a generic conceptual framework for understanding how interventions may promote behavior change. To minimize these problems, and thereby enhance likely intervention effectiveness, four sequential types of formative studies are proposed: targeted behavior validation, targeted mediator validation, intervention procedure validation, and pilot feasibility intervention. Implementing these studies would establish the relationships at each step in the mediating variable model, thereby maximizing the likelihood that an intervention would work and its effects would be detected. Building consensus among researchers, funding agencies, and journal editors on distinct intervention development studies should avoid identified limitations and move the field forward.

  6. Discharge Mechanism in Voids at Sub-Atmospheric Pressures

    OpenAIRE

    B.Ramachandra; Nema, RS

    1998-01-01

    The physical processes occurring during partial discharges (PD) in voids in solid dielectrics are complicated due to the lack of knowledge of void shape, location and gas pressure. Fast oscilloscopic techniques are needed to measure the build up and decay of current as a function of time for single discharges. The purpose of the present work is to investigate the mechanism of the discharge in artificial voids in thin polypropylene (PP) films at different sub-atmospheric pressures. Efforts hav...

  7. Quantifying Effects of Voids in Woven Ceramic Matrix Composites

    Science.gov (United States)

    Goldsmith, Marlana B.; Sankar, Bhavani V.; Haftka, Raphael T.; Goldberg, Robert K.

    2013-01-01

    Randomness in woven ceramic matrix composite architecture has been found to cause large variability in stiffness and strength. The inherent voids are an aspect of the architecture that may cause a significant portion of the variability. A study is undertaken to investigate the effects of many voids of random sizes and distributions. Response surface approximations were formulated based on void parameters such as area and length fractions to provide an estimate of the effective stiffness. Obtaining quantitative relationships between the properties of the voids and their effects on stiffness of ceramic matrix composites are of ultimate interest, but the exploratory study presented here starts by first modeling the effects of voids on an isotropic material. Several cases with varying void parameters were modeled which resulted in a large amount of variability of the transverse stiffness and out-of-plane shear stiffness. An investigation into a physical explanation for the stiffness degradation led to the observation that the voids need to be treated as an entity that reduces load bearing capabilities in a space larger than what the void directly occupies through a corrected length fraction or area fraction. This provides explanation as to why void volume fraction is not the only important factor to consider when computing loss of stiffness.

  8. Dynamics of voids and their shapes in redshift space

    Science.gov (United States)

    Maeda, Kei-ichi; Sakai, Nobuyuki; Triay, Roland

    2011-08-01

    We investigate the dynamics of a single spherical void embedded in a Friedmann-Lemaȋtre universe, and analyze the void shape in the redshift space. We find that the void in the redshift space appears as an ellipse shape elongated along the line of sight (i.e., an opposite deformation to the Kaiser effect). Applying this result to observed void candidates at the redshift z ~ 1-2, it may provide us with a new method to evaluate the cosmological parameters, in particular the value of a cosmological constant.

  9. Numerical implementation of constitutive material law for simulating the kinkband formation in fiber composites

    DEFF Research Database (Denmark)

    Veluri, Badrinath; Jensen, Henrik Myhre

    2011-01-01

    Finite element models with a constitutive material behavior that represents the non-linear response of fiber composites are used to simulate the compressive failure mechanism i.e. kinkband formation. A constitutive material law in framework of micromechanical modeling containing comprehensive...... constitutive equations for the constituent materials is adopted to model the non-linear behavior of the unidirectional layered materials. This material law is implemented as UMAT user subroutine in ABAQUS/Standard to study kinkband formation. The methodology provides a procedure to investigate the kinkband...... formation due to fiber misalignment for various complex structures having voids and material discontinuities that occur normally during the manufacture of these unidirectional fiber composites....

  10. Formats

    Directory of Open Access Journals (Sweden)

    Gehmann, Ulrich

    2012-03-01

    Full Text Available In the following, a new conceptual framework for investigating nowadays’ “technical” phenomena shall be introduced, that of formats. The thesis is that processes of formatting account for our recent conditions of life, and will do so in the very next future. It are processes whose foundations have been laid in modernity and which will further unfold for the time being. These processes are embedded in the format of the value chain, a circumstance making them resilient to change. In addition, they are resilient in themselves since forming interconnected systems of reciprocal causal circuits.Which leads to an overall situation that our entire “Lebenswelt” became formatted to an extent we don’t fully realize, even influencing our very percep-tion of it.

  11. Design of formative assessment model for professional behavior using stages of change theory.

    Science.gov (United States)

    Hashemi, Akram; Mirzazadeh, Azim; Shirazi, Mandana; Asghari, Fariba

    2016-01-01

    Background: Professionalism is a core competency of physicians. This study was conducted to design a model for formative assessment of professional commitment in medical students according to stages of change theory. Methods: In this qualitative study, data were collected through literature review & focus group interviews in the Tehran University of Medical Sciences in 2013 and analyzed using content analysis approach. Results: Review of the literature and results of focus group interviews led to design a formative assessment model of professional commitment in three phases, including pre-contemplation, contemplation, and readiness for behavior change that each one has interventional and assessment components. In the second phase of the study, experts' opinion collected in two main categories: the educational environment (factors related to students, students' assessment and educational program); and administrative problems (factors related to subcultures, policymakers or managers and budget). Moreover, there was a section of recommendations for each category related to curriculum, professors, students, assessments, making culture, the staff and reinforcing administrative factors. Conclusion: This type of framework analysis made it possible to develop a conceptual model that could be effective on forming the professional commitment and behavioral change in medical students.

  12. Voiding patterns in men evaluated by a questionnaire survey

    DEFF Research Database (Denmark)

    Sommer, P; Nielsen, K K; Bauer, T

    1990-01-01

    A questionnaire on obstructive and irritative voiding symptoms was sent to 572 men aged between 20 and 79 years, selected at random from the National Register; 337 questionnaires were completed. None of the responders had consulted a doctor because of voiding symptoms. There was a significant...

  13. STRESS CONCENTRATION DUE TO A SPHERICAL VOID UNDER HERTZIAN CONTACT

    Directory of Open Access Journals (Sweden)

    Stelian ALACI,

    2010-06-01

    Full Text Available The present paper presents the method of estimating the stress concentrator effect of a spherical void from an elastic half-space. An essential part consists in estimation of FEM error by finding the contact pressure from half-plane using an analytical method. Next, the stress concentrator effect of the same void, except for placed into elastic space, is found.

  14. Extended void merging tree algorithm for self-similar models

    NARCIS (Netherlands)

    Russell, Esra

    In hierarchical evolution, voids exhibit two different behaviours related with their surroundings and environments, they can merge or collapse. These two different types of void processes can be described by the two-barrier excursion set formalism based on Brownian random walks. In this study, the

  15. Old Stellar Populations of The VGS Void Galaxies

    NARCIS (Netherlands)

    Beygu, Burcu; Jarrett, Thomas; Jarrett, Tom; van de Weygaert, Rien; Kreckel, Kathryn; van der Hulst, Thijs; van Gorkom, Jacqueline

    Cosmic voids form an essential ingredient of the Cosmic Web and may harbour a systematically different population of galaxies. Largely unaffected by the complex processes modifying galaxies in high-density environments, the pristine and isolated void regions must hold important clues to the

  16. Voids and the Cosmic Web: cosmic depression & spatial complexity

    NARCIS (Netherlands)

    van de Weygaert, Rien; Shandarin, S.; Saar, E.; Einasto, J.

    2016-01-01

    Voids form a prominent aspect of the Megaparsec distribution of galaxies and matter. Not only do theyrepresent a key constituent of the Cosmic Web, they also are one of the cleanest probesand measures of global cosmological parameters. The shape and evolution of voids are highly sensitive tothe

  17. The relationship between children with voiding problems and their parents

    NARCIS (Netherlands)

    Labrie, J.; de Jong, T. P. V. M.; Nieuwhof-Leppink, A.; van der Deure, J.; Vijverberg, M. A. W.; van der Vaart, C. H.

    2010-01-01

    We determined whether parents of children with overactive bladder and dysfunctional voiding had had similar symptoms in childhood. A case-control study was done in parents with and without children with overactive bladder or dysfunctional voiding. All were recruited from an outpatient clinic.

  18. 21 CFR 1305.28 - Canceling and voiding electronic orders.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Canceling and voiding electronic orders. 1305.28 Section 1305.28 Food and Drugs DRUG ENFORCEMENT ADMINISTRATION, DEPARTMENT OF JUSTICE ORDERS FOR SCHEDULE I AND II CONTROLLED SUBSTANCES Electronic Orders § 1305.28 Canceling and voiding electronic orders...

  19. Nonlocal effects on localization in a void-sheet

    DEFF Research Database (Denmark)

    Tvergaard, Viggo; Needleman, A.

    1997-01-01

    For a nonlocal damage model it is expected that the characteristic material length relates to the damage mechanism. In the case of ductile fracture the most relevant length scales would be the average void radius or spacing. Cell model computations representing a single row of Voids in an infinite...... solid under plane strain conditions are here used to compare with predictions of a nonlocal Version of a porous ductile material model. Both the critical strain for the onset of plastic flow localization and the slope of the stress-strain curve in the post-localization range are compared...... the material characteristic length scales with the void radius, whereas for transversely aligned voids the scaling is with the void spacing. (C) 1997 Elsevier Science Ltd....

  20. Study of galaxies in the Lynx-Cancer void. IV. Photometric properties

    Science.gov (United States)

    Perepelitsyna, Yu. A.; Pustilnik, S. A.; Kniazev, A. Yu.

    We present the results of a photometric study of 85 objects from the updated sample of galaxies residing in the nearby Lynx--Cancer void. We perform our photometry on u, g, r, and i-band images of the Sloan Digital Sky Survey. We determine model-independent galaxy parameters such as the integrated magnitudes and colors, effective radii and the corresponding surface brightness values, optical radii and Holmberg radii. We analyze the radial surface brightness profiles to determine the central brightness values and scale lengths of the model discs. We analyze the colors of the outer parts of the galaxies and compare them with model evolutionary tracks computed using the PEGASE2 software package. This allowed us to estimate the time T_SF elapsed since the onset of star formation, which turned out to be on the order of the cosmological time T_0 for the overwhelming majority of the galaxies studied. However, for 13 galaxies of the sample the time T_SF does not exceed T_0/2 ~ 7 Gyr, and for 7 of them T_SF -13.2. We use the integrated magnitudes and colors to estimate the stellar masses of the galaxies. We estimate the parameter M(HI)/L_B and the gas mass fractions for void galaxies with known HI-line fluxes. A small subgroup (about 10%) of the gas-richest void galaxies with M(HI)/L_B > 2.5 has gas mass fractions that reach 94-99%. The outer regions of many of these galaxies show atypically blue colors. To test various statistical differences between void galaxies and galaxies from the samples selected using more general criteria, we compare some of the parameters of void galaxies with similar data for the sample of 195 galaxies from the Equatorial Survey (ES) based on a part of the HIPASS blind HI survey. abridged

  1. Seismic Techniques for Subsurface Voids Detection

    Science.gov (United States)

    Gritto, Roland; Korneev, Valeri; Elobaid Elnaiem, Ali; Mohamed, Fathelrahman; Sadooni, Fadhil

    2016-04-01

    A major hazards in Qatar is the presence of karst, which is ubiquitous throughout the country including depressions, sinkholes, and caves. Causes for the development of karst include faulting and fracturing where fluids find pathways through limestone and dissolve the host rock to form caverns. Of particular concern in rapidly growing metropolitan areas that expand in heretofore unexplored regions are the collapse of such caverns. Because Qatar has seen a recent boom in construction, including the planning and development of complete new sub-sections of metropolitan areas, the development areas need to be investigated for the presence of karst to determine their suitability for the planned project. In this paper, we present the results of a study to demonstrate a variety of seismic techniques to detect the presence of a karst analog in form of a vertical water-collection shaft located on the campus of Qatar University, Doha, Qatar. Seismic waves are well suited for karst detection and characterization. Voids represent high-contrast seismic objects that exhibit strong responses due to incident seismic waves. However, the complex geometry of karst, including shape and size, makes their imaging nontrivial. While karst detection can be reduced to the simple problem of detecting an anomaly, karst characterization can be complicated by the 3D nature of the problem of unknown scale, where irregular surfaces can generate diffracted waves of different kind. In our presentation we employ a variety of seismic techniques to demonstrate the detection and characterization of a vertical water collection shaft analyzing the phase, amplitude and spectral information of seismic waves that have been scattered by the object. We used the reduction in seismic wave amplitudes and the delay in phase arrival times in the geometrical shadow of the vertical shaft to independently detect and locate the object in space. Additionally, we use narrow band-pass filtered data combining two

  2. Determination of the equivalent intergranular void ratio - Application to the instability and the critical state of silty sand

    Science.gov (United States)

    Nguyen, Trung-Kien; Benahmed, Nadia; Hicher, Pierre-Yves

    2017-06-01

    This paper presents an experimental study of mechanical response of natural Camargue silty sand. The analysis of test results used the equivalent intergranular void ratio instead of the global void ratio. The calculation of equivalent intergranular void ratio requires the determination of parameter b which represents, physically, the fraction of active fines participating on the chain forces network, hence the strength of the soil. A new formula for determining the parameter b by using an approach based on the coordination number distribution and probability calculation is proposed. The validation of the developed relationship was done through back-analysis of published datasets in literature on the effect of fines content on silty sand behavior. It is shown that the equivalent intergranular void ratio calculated with the b value obtained by the new formula is able to provide strong correlation to not only the critical state of but also the onset of instability of various silty sands, in different terms as peak deviator stress, peak stress ratio or cyclic resistance. Therefore, it is suggested that the use of the equivalent void ratio concept and the new b calculating formula is highly desirable in predicting of the silty sand behavior.

  3. Determination of the equivalent intergranular void ratio - Application to the instability and the critical state of silty sand

    Directory of Open Access Journals (Sweden)

    Nguyen Trung-Kien

    2017-01-01

    Full Text Available This paper presents an experimental study of mechanical response of natural Camargue silty sand. The analysis of test results used the equivalent intergranular void ratio instead of the global void ratio. The calculation of equivalent intergranular void ratio requires the determination of parameter b which represents, physically, the fraction of active fines participating on the chain forces network, hence the strength of the soil. A new formula for determining the parameter b by using an approach based on the coordination number distribution and probability calculation is proposed. The validation of the developed relationship was done through back-analysis of published datasets in literature on the effect of fines content on silty sand behavior. It is shown that the equivalent intergranular void ratio calculated with the b value obtained by the new formula is able to provide strong correlation to not only the critical state of but also the onset of instability of various silty sands, in different terms as peak deviator stress, peak stress ratio or cyclic resistance. Therefore, it is suggested that the use of the equivalent void ratio concept and the new b calculating formula is highly desirable in predicting of the silty sand behavior.

  4. Essential processes for cognitive behavioral clinical supervision: Agenda setting, problem-solving, and formative feedback.

    Science.gov (United States)

    Cummings, Jorden A; Ballantyne, Elena C; Scallion, Laura M

    2015-06-01

    Clinical supervision should be a proactive and considered endeavor, not a reactive one. To that end, supervisors should choose supervision processes that are driven by theory, best available research, and clinical experience. These processes should be aimed at helping trainees develop as clinicians. We highlight 3 supervision processes we believe should be used at each supervision meeting: agenda setting, encouraging trainee problem-solving, and formative feedback. Although these are primarily cognitive-behavioral skills, they can be helpful in combination with other supervision models. We provide example dialogue from supervision exchanges, and discuss theoretical and research support for these processes. Using these processes not only encourages trainee development but also models for them how to use the same processes and approaches with clients. (c) 2015 APA, all rights reserved).

  5. Mechanisms of defect complex formation and environmental-assisted fracture behavior of iron aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, B.R.; Muratov, L.S.; Kang, B.S.J.; Li, K.Z. [West Virginia Univ., Morgantown, WV (United States)

    1997-12-01

    Iron aluminide has excellent corrosion resistance in high-temperature oxidizing-sulfidizing environments; however, there are problems at room and medium temperature with hydrogen embrittlement as related to exposure to moisture. In this research, a coordinated computational modeling/experimental study of mechanisms related to environmental-assisted fracture behavior of selected iron aluminides is being undertaken. The modeling and the experimental work will connect at the level of coordinated understanding of the mechanisms for hydrogen penetration and for loss of strength and susceptibility to fracture. The focus of the modeling component at this point is on the challenging question of accurately predicting the iron vacancy formation energy in Fe{sub 3}A{ell} and the subsequent tendency, if present, for vacancy clustering. The authors have successfully performed, on an ab initio basis, the first calculation of the vacancy formation energy in Fe{sub 3}A{ell}. These calculations include lattice relaxation effects which are quite large. This has significant implications for vacancy clustering effects with consequences to be explored for hydrogen diffusion. The experimental work at this stage has focused on the relationship of the choice and concentration of additives to the improvement of resistance to hydrogen embrittlement and hence to the fracture behavior. For this reason, comparative crack growth tests of FA-186, FA-187, and FA-189 iron aluminides (all with basic composition of Fe-28A{ell}-5Cr, at % with micro-alloying additives of Zr, C or B) under, air, oxygen, or water environment have been performed. These tests showed that the alloys are susceptible to room temperature hydrogen embrittlement in both B2 and DO{sub 3} conditions. Test results indicated that FA-187, and FA-189 are intrinsically more brittle than FA-186.

  6. Urinary bladder rupture during voiding cystourethrography

    Directory of Open Access Journals (Sweden)

    Kyong Ok Lee

    2012-05-01

    Full Text Available Voiding cystourethrography (VCUG is a commonly performed diagnostic procedure for the evaluation of vesicoureteral reflux with urinary tract infection or congenital renal diseases in children. The procedure is relatively simple and cost-effective, and complications are very rare. The iatrogenic complication of VCUG range from discomfort, urinary tract infection to bacteremia, as well as bladder rupture. Bladder rupture is a rare complication of VCUG, and only a few cases were reported. Bladder rupture among healthy children during VCUG is an especially uncommon event. Bladder rupture associated with VCUG is usually more common in chronically unused bladders like chronic renal failure. Presented is a case of bladder rupture that occurred during a VCUG in a healthy 9-monthold infant, due to instilled action of dye by high pressure. This injury completely healed after 7 days of operation, and it was confirmed with a postoperative cystography. The patient’s bladder volume, underlying disease, velocity of the contrast media instilled, catheter size, and styles of instillation are important factors to prevent bladder rupture during VCUG. Management of bladder rupture should be individualized, but the majority of infants are treated with the operation. In conclusion, bladder rupture is a rare complication, however, delicate attention is needed in order to prevent more dire situations.

  7. Sintering Behavior and Microstructure Formation of Titanium Aluminide Alloys Processed by Metal Injection Molding

    Science.gov (United States)

    Soyama, Juliano; Oehring, Michael; Ebel, Thomas; Kainer, Karl Ulrich; Pyczak, Florian

    2017-04-01

    The sintering behavior of metal injection molded titanium aluminide alloys, their microstructure formation and resulting mechanical properties were investigated. As reference material, the alloy Ti-45Al-5Nb-0.2B-0.2C at.% (TNB-V5) was selected. Additionally, two other variations with Mo and Mo + Si additions were prepared: Ti-45Al-3Nb-1Mo-0.2B-0.2C at.% and Ti-45Al-3Nb-1Mo-1Si-0.2B-0.2C at.%. The results indicate that the optimum sintering temperature was slightly above the solidus line. With proper sintering parameters, very low porosities (<0.5%) and fine microstructures with a colony size <85 µm could be achieved. Considering the sintering temperatures applied, the phase transformations upon cooling could be described as L + β → β → α + β → α → α + γ → α2 + γ, which was in agreement with the microstructures observed. The effects of Mo and Si were opposite regarding the sintering behavior. Mo addition led to an increase in the optimum sintering temperature, whereas Si caused a significant decrease.

  8. The association of age of toilet training and dysfunctional voiding

    Directory of Open Access Journals (Sweden)

    Hodges SJ

    2014-10-01

    Full Text Available Steve J Hodges, Kyle A Richards, Ilya Gorbachinsky, L Spencer KraneDepartment of Urology, Wake Forest University, Winston-Salem, NC, USAObjective: To determine whether age of toilet training is associated with dysfunctional voiding in children.Materials and methods: We compared patients referred to the urologic clinics for voiding dysfunction with age-matched controls without urinary complaints. Characteristics including age and reason for toilet training, method of training, and encopresis or constipation were compared between both groups.Results: Initiation of toilet training prior to 24 months and later than 36 months of age were associated with dysfunctional voiding. However, dysfunctional voiding due to late toilet training was also associated with constipation.Conclusion: Dysfunctional voiding may be due to delayed emptying of the bowel and bladder by children. The symptoms of dysfunctional voiding are more common when toilet training early, as immature children may be less likely to empty in a timely manner, or when training late due to (or in association with constipation.Keywords: voiding dysfunction, constipation

  9. Voids characteristics of asphaltic concrete containing coconut shell

    Science.gov (United States)

    Ezree Abdullah, Mohd; Hannani Madzaili, Amirah; Putra Jaya, Ramadhansyah; Yaacob, Haryati; Hassan, Norhidayah Abdul; Nazri, Fadzli Mohamed

    2017-07-01

    Asphalt durability is often linked to the thickness of the asphalt coating on the aggregate particles. In order to have adequate film thickness in asphaltic concrete, there must be sufficient space between the aggregate particles in the compacted pavement. This void space is referred to as voids in total mix (VTM), voids with filled bitumen (VFB), and voids in mineral aggregate (VMA). Hence, this study investigates the performance of coconut shell (CS) as coarse aggregate replacement on voids characteristics of asphaltic concrete. Four CS were used as coarse aggregates replacement in asphalt mixture namely 0%, 10%, 20%, 30%, and 40% (by weight volume). The voids properties of asphalt mixture were determined based on Marshall Mix design test. Test results show that VTM and VMA values were decrease with the increasing bitumen content where VFB was increase with increasing bitumen content. Furthermore, increasing the percentage of coconut shell in asphalt mixture was found to increases the voids value up to a peak level and then decreases with further additions of CS.

  10. Intergalactic Hydrogen Clouds at Low Redshift: Connections to Voids and Dwarf Galaxies

    Science.gov (United States)

    Shull, J. Michael; Stocke, John T.; Penton, Steve

    1996-01-01

    We provide new post-COSTAR data on one sightline (Mrk 421) and updated data from another (I Zw 1) from our Hubble Space Telescope (HST) survey of intergalactic Ly(alpha) clouds located along sightlines to four bright quasars passing through well-mapped galaxy voids (16000 km/s pathlength) and superclusters (18000 km/s). We report two more definite detections of low-redshift Ly(alpha) clouds in voids: one at 3047 km/s (heliocentric) toward Mrk 421 and a second just beyond the Local Supercluster at 2861 km/s toward I Zw 1, confirming our earlier discovery of Ly(alpha) absorption clouds in voids (Stocke et al., ApJ, 451, 24). We have now identified ten definite and one probable low-redshift neutral hydrogen absorption clouds toward four targets, a frequency of approximately one absorber every 3400 km/s above 10(exp 12.7/sq cm column density. Of these ten absorption systems, three lie within voids; the probable absorber also lies in a void. Thus, the tendency of Ly(alpha) absorbers to 'avoid the voids' is not as clear as we found previously. If the Ly(alpha) clouds are approximated as homogeneous spheres of 100 kpc radius, their masses are approximately 10(exp 9)solar mass (about 0.01 times that of bright L* galaxies) and they are 40 times more numerous, comparable to the density of dwarf galaxies and of low-mass halos in numerical CDM simulations. The Ly(alpha) clouds contribute a fraction Omega(sub cl)approximately equals 0.003/h(sub 75) to the closure density of the universe, comparable to that of luminous matter. These clouds probably require a substantial amount of nonbaryonic dark matter for gravitational binding. They may represent extended haloes of low-mass protogalaxies which have not experienced significant star formation or low-mass dwarf galaxies whose star formation ceased long ago, but blew out significant gaseous material.

  11. Clusters, voids and reconstructions of the cosmic web

    Science.gov (United States)

    Bos, E. G. Patrick

    2016-12-01

    The Universe is filled for 95% with dark matter and energy that we cannot see. Of the remaining 5% normal matter we can only see a small part. However, if we want to study the Universe as a whole, we will have to get to know it for 100%. We have to uncover indirectly where dark matter is hiding and what is the nature of dark energy. In this thesis we explore two such methods. The first part describes how we can use the large empty regions between galaxies, "voids", to learn more about dark energy. We converted our theoretical simulations to a model of real observations of galaxies. In this model, we perform the same measurements as we would in real observations. This way, we show that it is indeed possible to unravel the nature of dark energy. The second part is based on our computer code: BARCODE. It unites two models: a physical model of the formation of the Cosmic Web, and a description of the observational effects of (clusters of) galaxies, in particular the effect of redshift on distance measurements. It allows us to back-trace our observations to the primordial conditions. These enable us to trace all (dark) matter, also that which we did not directly observe. The result is a reconstruction of the complete Cosmic Web. In these, we studied "filaments". These objects have not yet been extensively studied. BARCODE will enable further study, e.g. by using it to find observable filaments.

  12. Assessment of void swelling in austenitic stainless steel PWR core internals.

    Energy Technology Data Exchange (ETDEWEB)

    Chung, H. M.; Energy Technology

    2006-01-31

    As many pressurized water reactors (PWRs) age and life extension of the aged plants is considered, void swelling behavior of austenitic stainless steel (SS) core internals has become the subject of increasing attention. In this report, the available database on void swelling and density change of austenitic SSs was critically reviewed. Irradiation conditions, test procedures, and microstructural characteristics were carefully examined, and key factors that are important to determine the relevance of the database to PWR conditions were evaluated. Most swelling data were obtained from steels irradiated in fast breeder reactors at temperatures >385 C and at dose rates that are orders of magnitude higher than PWR dose rates. Even for a given irradiation temperature and given steel, the integral effects of dose and dose rate on void swelling should not be separated. It is incorrect to extrapolate swelling data on the basis of 'progressive compounded multiplication' of separate effects of factors such as dose, dose rate, temperature, steel composition, and fabrication procedure. Therefore, the fast reactor data should not be extrapolated to determine credible void swelling behavior for PWR end-of-life (EOL) or life-extension conditions. Although the void swelling data extracted from fast reactor studies is extensive and conclusive, only limited amounts of swelling data and information have been obtained on microstructural characteristics from discharged PWR internals or steels irradiated at temperatures and at dose rates comparable to those of a PWR. Based on this relatively small amount of information, swelling in thin-walled tubes and baffle bolts in a PWR is not considered a concern. As additional data and relevant research becomes available, the newer results should be integrated with existing data, and the worthiness of this conclusion should continue to be scrutinized. PWR baffle reentrant corners are the most likely location to experience high swelling

  13. Qualitative separation of the effect of voids on the static mechanical properties of hygrothermally conditioned carbon/epoxy composites

    Directory of Open Access Journals (Sweden)

    2011-08-01

    Full Text Available The paper investigates the effect of voids and hygrothermal conditions on bending, compressive, and interlaminar shear strength (ILSS of T300/914 composite laminates. By adopting different autoclave pressures during a cure cycle, specimens with three different void contents ranging from 0.33% to 1.50% were obtained. Experimental results reveal that compressive, bending strength, and ILSS decrease with increasing void contents and immersion time. The most significant decrease in strength of aged specimens is in the ILSS and compressive strength, followed by the bending strength. The effect of voids on the absorption/desorption behavior is also discussed. For a similar porosity, the compressive strength and ILSS of dried specimens are higher than that of the aged specimens, while they are lower than that of the unaged specimens. The bending strength of the dried specimens is higher than that of the unaged specimens. The experimental results are explained by the supportive micrographs that illustrate different types of voids and their morphology before and after moisture absorption/desorption.

  14. Effects of Voids on Postbuckling Delamination Growth in Unidirectional Composites

    National Research Council Canada - National Science Library

    Zhuang, Linqi; Talreja, Ramesh

    .... In the finite element model developed, a through-width delamination is introduced close to one surface of a flat panel, and a void is placed in the delamination plane ahead of each delamination front...

  15. A variational void coalescence model for ductile metals

    KAUST Repository

    Siddiq, Amir

    2011-08-17

    We present a variational void coalescence model that includes all the essential ingredients of failure in ductile porous metals. The model is an extension of the variational void growth model by Weinberg et al. (Comput Mech 37:142-152, 2006). The extended model contains all the deformation phases in ductile porous materials, i.e. elastic deformation, plastic deformation including deviatoric and volumetric (void growth) plasticity followed by damage initiation and evolution due to void coalescence. Parametric studies have been performed to assess the model\\'s dependence on the different input parameters. The model is then validated against uniaxial loading experiments for different materials. We finally show the model\\'s ability to predict the damage mechanisms and fracture surface profile of a notched round bar under tension as observed in experiments. © Springer-Verlag 2011.

  16. Mechanisms of void coarsening in helium implanted silicon

    CERN Document Server

    Evans, J H

    2002-01-01

    There has been recent discussion of the mechanisms that give rise to the observed coarsening of void populations introduced into silicon by implanting helium and then annealing to remove the helium. Over the temperature range from approximately 700 to 1000 degree sign C and beyond, further annealing leads to an increase of the average void size and decrease in void density. This paper sets out to calculate the coarsening expected from the two primary potential mechanisms, migration and coalescence (M and C) and Ostwald ripening (OR). The methodology of the calculations is carefully set out together with the surface diffusion and vacancy diffusion parameters on which the mechanisms depend. For moderate anneal temperatures, up to 1000 degree sign C, it would seem unlikely that OR can play any part in void coarsening. On the other hand, M and C calculations show that this mechanism gives results consistent with the size range found in experimental results.

  17. Void Points, Rosettes, and a Brief History of Planetary Astronomy

    Science.gov (United States)

    Kosso, Peter

    2013-12-01

    Almost all models of planetary orbits, from Aristotle through Newton, include void points, empty points in space that have an essential role in defining the orbit. By highlighting the role of these void points, as well as the rosette pattern of the orbit that often results, I bring out different features in the history of planetary astronomy and place a different emphasis on its revolutionary changes, different from those rendered in terms of epicycles or the location of the earth.

  18. Uroflowmetry in neurologically normal children with voiding disorders

    DEFF Research Database (Denmark)

    Jensen, K M; Nielsen, K.K.; Kristensen, E S

    1985-01-01

    of neurological deficits underwent a complete diagnostic program including intravenous urography, voiding cystography and cystoscopy as well as spontaneous uroflowmetry, cystometry-emg and pressure-flow-emg study. The incidence of dyssynergia was 22%. However, neither the flow curve pattern nor single flow...... variables were able to identify children with dyssynergia. Consequently uroflowmetry seems inefficient in the screening for dyssynergia in neurological normal children with voiding disorders in the absence of anatomical bladder outlet obstruction....

  19. Influence of nickel and beryllium content on swelling behavior of copper irradiated with fast neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Singh, B.N.; Garner, F.A.; Edwards, D.J. [Pacific Northwest National Lab., Richland, WA (United States); Evans, J.H.

    1996-10-01

    In the 1970`s, the effects of nickel content on the evolution of dislocation microstructures and the formation and growth of voids in Cu-Ni alloys were studied using 1 MeV electrons in a high voltage electron microscope. The swelling rate was found to decrease rapidly with increasing nickel content. The decrease in the swelling rate was associated with a decreasing void growth rate with increasing nickel content at irradiation temperatures up to 450{degrees}C. At 500{degrees}C, both void size and swelling rate were found to peak at 1 and 2% Ni, respectively, and then to decrease rapidly with increasing nickel content. However, recent work has demonstrated that the swelling behavior of Cu-5%Ni irradiated with fission neutrons is very similar for that of pure copper. The present experiments were designed to investigate this apparent discrepancy.

  20. ACK filling void first algorithm and performance for asynchronous OPS

    Science.gov (United States)

    Liu, Huanlin; Shi, Yonghe; Chen, Qianbin; Pan, Yingjun

    2007-11-01

    OPS with feedback shared FDL buffer produce large voids due to FDL buffers only supplying discrete step delay and causing FDL queue virtually occupation. By analyzing the TCP traffic and ACK packets feature, the ACK packet void filling first scheduling is presented to decrease packet loss rate and to reduce the FDL voids. When the FDL buffer void size is fit for the ACK packet, the ACK packet is scheduled to FDL immediately. An ACK and non-ACK packets difference and process flow is designed according the TCP packet frame structure. Compared with the conventional FIFO scheduling and smallest FDL void first scheduling, the algorithm reduces greatly the number of ACK occupying the FDL buffer and eliminates large numbers of ACK's bad influence on efficiency of IP data transmission under different FDL buffer depth and traffic load. The results of simulation show that the proposed scheduling makes use of ACK packets first void filling scheduling mechanism to reduce FDL excess load, increases output utilization and reduce packet loss ratio for asynchronous optical network. This approach is shown to minimize the FDL numbers with the feature of high stabilization and photonic integration and to improve real time TCP traffic performance for Internet network.

  1. Investigation of flow regime in debris bed formation behavior with nonspherical particles

    Directory of Open Access Journals (Sweden)

    Songbai Cheng

    2018-02-01

    Full Text Available It is important to clarify the characteristics of flow regimes underlying the debris bed formation behavior that might be encountered in core disruptive accidents of sodium-cooled fast reactors. Although in our previous publications, by applying dimensional analysis technique, an empirical model, with its reasonability confirmed over a variety of parametric conditions, has been successfully developed to predict the regime transition and final bed geometry formed, so far this model is restricted to predictions of debris mixtures composed of spherical particles. Focusing on this aspect, in this study a new series of experiments using nonspherical particles have been conducted. Based on the knowledge and data obtained, an extension scheme is suggested with the purpose of extending the base model to cover the particle-shape influence. Through detailed analyses and given our current range of experimental conditions, it is found that, by coupling the base model with this scheme, respectable agreement between experiments and model predictions for the regime transition can be achieved for both spherical and nonspherical particles. Knowledge and evidence from our work might be utilized for the future improvement of design of an in-vessel core catcher as well as the development and verification of sodium-cooled fast reactor severe accident analysis codes in China.

  2. Corrosion Behavior and Oxide Film Formation of T91 Steel under Different Water Chemistry Operation Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, D. Q.; Shi, C.; Li, J.; Gao, L. X. [Shanghai University of Electric Power, Shanghai (China); Lee, K. Y. [Dalian University of Technology, Dalian (China)

    2017-02-15

    The corrosion behavior of a ferritic/martensitic steel T91 exposed to an aqueous solution containing chloride and sulfate ions is investigated depending on the stimulated all-volatile treatment (AVT) and under oxygenated treatment (OT) conditions. The corrosion of T91 steel under OT condition is severe, while the corrosion under AVT condition is not. The co-existence of chloride and sulfate ions has antagonistic effect on the corrosion of T91 steel in both AVT and OT conditions. Unlike to corrosion resistance in the aqueous solution, OT pretreatment provides T91 steel lower oxidation-resistance than VAT pretreatment. From scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) and X-ray diffraction (XRD) analysis, the lower corrosion resistance in the aqueous solution by VAT conditions possibly is due to the formation of pits. In addition, the lower oxidation resistance of T91 steel pretreated by OT conditions is explained as follows: the cracks formed during the immersion under OT conditions accelerated peeling-off rate of the oxide film.

  3. Damage formation, fatigue behavior and strength properties of ZrO{sub 2}-based ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Kozulin, A. A., E-mail: kozulyn@ftf.tsu.ru; Kulkov, S. S. [Tomsk State University, Tomsk, 634050 (Russian Federation); Narikovich, A. S.; Leitsin, V. N. [Immanuel Kant Baltic Federal University, Kaliningrad, 236041 (Russian Federation); Kulkov, S. N., E-mail: kulkov@ispms.ru [Tomsk State University, Tomsk, 634050 (Russian Federation); Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation)

    2016-08-02

    It is suggested that a non-destructive testing technique using a three-dimensional X-ray tomography be applied to detecting internal structural defects and monitoring damage formation in a ceramic composite structure subjected to a bending load. Three-point bending tests are used to investigate the fatigue behavior and mechanical and physical properties of medical-grade ZrO{sub 2}-based ceramics. The bending strength and flexural modulus are derived under static conditions at a loading rate of 2 mm/min. The fatigue strength and fatigue limit under dynamic loading are investigated at a frequency of 10 Hz in three stress ranges: 0.91–0.98, 0.8–0.83, and 0.73–0.77 MPa of the static bending strength. The average values of the bending strength and flexural modulus of sintered specimens are 43 MPa and 22 GPa, respectively. The mechanical properties of the ceramics are found to be similar to those of bone tissues. The testing results lead us to conclude that the fatigue limit obtained from 10{sup 5} stress cycles is in the range 33–34 MPa, i.e. it accounts for about 75% of the static bending strength for the test material.

  4. An Optimal Cure Process to Minimize Residual Void and Optical Birefringence for a LED Silicone Encapsulant

    Directory of Open Access Journals (Sweden)

    Min-Jae Song

    2014-05-01

    Full Text Available Silicone resin has recently attracted great attention as a high-power Light Emitting Diode (LED encapsulant material due to its good thermal stability and optical properties. In general, the abrupt curing reaction of the silicone resin for the LED encapsulant during the curing process induces reduction in the mechanical and optical properties of the LED product due to the generation of residual void and moisture, birefringence, and residual stress in the final formation. In order to prevent such an abrupt curing reaction, the reduction of residual void and birefringence of the silicone resin was observed through experimentation by introducing the multi-step cure processes, while the residual stress was calculated by conducting finite element analysis that coupled the heat of cure reaction and cure shrinkage. The results of experiment and analysis showed that it was during the three-step curing process that the residual void, birefringence, and residual stress reduced the most in similar tendency. Through such experimentation and finite element analysis, the study was able to confirm that the optimization of the LED encapsulant packaging process was possible.

  5. Void-swelling and precipitation in a neutron-irradiated, niobium-stabilised austenitic stainless steel

    Science.gov (United States)

    Williams, T. M.; Titchmarsh, J. M.; Arkell, D. R.

    1982-06-01

    Unstressed specimens of FV548 niobium-stabilised austenitic steel in three heat-treatment conditions (1150°C solutiontreated, 20% cold-worked, and 850°C aged) have been neutron-irradiated in the Dounreay Fast Reactor in the temperature range 380°-738°C and to displacement doses of up to 30 dpa. The irradiated specimens have been examined using transmission electron microscopy and EDX techniques to establish the void-swelling and precipitation behaviour under neutron irradiation. Where possible, the observations are compared with results obtained on type 316 steel. The similarities and differences in the behaviour of the two steels are used in an attempt to understand the factors affecting the precipitation under irradiation and the void-swelling behaviour of FV548 and type 316 steels. Irradiation is shown to enhance the formation of some precipitate phases (e.g. G-phase and carbides of the M 6C type) while having no effect on others (e.g. Sigma phase and M 23C 6). It is concluded that fine intragranular dispersions of niobium carbide particles play a major role in suppressing void-swelling in neutron-irradiated FV548 steel at relatively high irradiation temperatures.

  6. Sensitivity effects of void density and arrangements in a REBO high explosive

    Energy Technology Data Exchange (ETDEWEB)

    Herring, Stuart Davis [Los Alamos National Laboratory; Germann, Timothy C [Los Alamos National Laboratory; Gronbech - Jensen, Niels [Los Alamos National Laboratory

    2010-09-28

    The shock response of two-dimensional model, high explosive crystals with various arrangements of circular voids is explored. We simulate a piston impact using molecular dynamics simulations with a Reactive Empirical Bond Order (REBO) model potential for a sub-micron, sub-ns exothermic reaction in a diatomic molecular solid. In square lattices of voids all of one size, reducing that size or increasing the porosity while holding the other parameter fixed causes the hotspots to consume the material more quickly and detonation to occur sooner and at lower piston velocities. The early time behavior is seen to follow a very simple ignition and growth model. The hotspots are seen to collectively develop a broad pressure wave (a sonic, diffuse deflagration front) that, upon merging with the lead shock, transforms it into a detonation. The reaction yields produced by triangular lattices are not significantly different. With random void arrangements, the mean time to detonation is 15.5% larger than with the square lattice; the standard deviation of detonation delays is just 5.1%.

  7. Administration of riboflavin improves behavioral outcome and reduces edema formation and glial fibrillary acidic protein expression after traumatic brain injury.

    Science.gov (United States)

    Hoane, Michael R; Wolyniak, Joseph G; Akstulewicz, Stacy L

    2005-10-01

    Previous studies have shown that administration of riboflavin, vitamin B2, significantly reduced edema formation following experimental stroke. The present study evaluated the ability of B2 to improve behavioral function, reduce edema formation, and limit glial fibrillary acidic protein (GFAP) expression following frontal cortex contusion injury. Groups of rats were assigned to B2 (7.5 mg/kg) or saline (1.0 ml/kg) treatment conditions and received contusion injuries or sham procedures. Drug treatment was administered 15 min and 24 h following injury. Rats were examined on a variety of tests to measure sensorimotor performance (bilateral tactile removal test), and cognitive ability (acquisition of reference and working memory) in the Morris water maze. Administration of B2 following injury significantly reduced the behavioral impairments observed on the bilateral tactile removal test and improved the acquisition of both reference and working memory tests compared to saline-treated rats. The lesion analysis showed that B2 reduced the size of the lesion. Examination of GFAP expression around the lesion revealed that B2 significantly reduced the number of GFAP+ astrocytes. Edema formation following injury was also significantly reduced by B2 administration. These findings are the first to show that B2 administration significantly improved behavioral outcome and reduced lesion volume, edema formation, and the expression of GFAP following traumatic brain injury. These findings suggest that B2 may have therapeutic potential for the treatment of TBI.

  8. FEATURES OF INFLUENCE OF EMOTIONAL STRESS DURING PREGNANCY ON THE FORMATION OF EATING BEHAVIOR IN THE CHILD

    Directory of Open Access Journals (Sweden)

    J. R. Gardanova

    2016-01-01

    Full Text Available The actuality of the problem of high level of anxiety and the development of psycho-emotional disorders in women during pregnancy currently occupy a leading place in clinical practice. Pregnant "seize" the problem by using a non-adaptive coping and thereby form a similar pattern of behavior in stressful situation and in the fetus, perinatal-formed a similar pattern.Materials and methods. Clinical-descriptive, formulated the concept of the influence psycho-emotional stress and characteristics of the current pregnancy on the background of the formation of patterns of eating behavior in the fetus, followed by implementation after birth under the provisions of the dominant by A. A. Ukhtomsky, the theory of functional systems P. K. Anokhin, the endogeneity of the regularities of pathological processes, the pyramid of needs of A. Maslow.Results. As a result of the establishment of the concept, doctors will be able to identify the maladaptive pattern of eating behavior in pregnant women and to make timely prevention of the formation of this pattern in the fetus.Conclusion. The use of the developed concept could help doctors to identify the maladaptive pattern of eating behavior in pregnant women and make timely prevention of the formation of this pattern in the fetus.

  9. Effects of Lateral Funiculus Sparing, Spinal Lesion Level, and Gender on Recovery of Bladder Voiding Reflexes and Hematuria in Rats

    Science.gov (United States)

    Ferrero, Sunny L.; Brady, Tiffany D.; Dugan, Victoria P.; Armstrong, James E.; Hubscher, Charles H.

    2015-01-01

    Abstract Deficits in bladder function are complications following spinal cord injury (SCI), severely affecting quality of life. Normal voiding function requires coordinated contraction of bladder and urethral sphincter muscles dependent upon intact lumbosacral reflex arcs and integration of descending and ascending spinal pathways. We previously reported, in electrophysiological recordings, that segmental reflex circuit neurons in anesthetized male rats were modulated by a bilateral spino-bulbo-spinal pathway in the mid-thoracic lateral funiculus. In the present study, behavioral measures of bladder voiding reflexes and hematuria (hemorrhagic cystitis) were obtained to assess the correlation of plasticity-dependent recovery to the degree of lateral funiculus sparing and mid-thoracic lesion level. Adult rats received mid-thoracic-level lesions at one of the following severities: complete spinal transection; bilateral dorsal column lesion; unilateral hemisection; bilateral dorsal hemisection; a bilateral lesion of the lateral funiculi and dorsal columns; or a severe contusion. Voiding function and hematuria were evaluated by determining whether the bladder was areflexic (requiring manual expression, i.e., “crede maneuver”), reflexive (voiding initiated by perineal stroking), or “automatic” (spontaneous voiding without caretaker assistance). Rats with one or both lateral funiculi spared (i.e., bilateral dorsal column lesion or unilateral hemisection) recovered significantly faster than animals with bilateral lateral funiculus lesions, severe contusion, or complete transection. Bladder reflex recovery time was significantly slower the closer a transection lesion was to T10, suggesting that proximity to the segmental sensory and sympathetic innervation of the upper urinary tract (kidney, ureter) should be avoided in the choice of lesion level for SCI studies of micturition pathways. In addition, hematuria duration was significantly longer in males, compared to

  10. Simulation-aided constitutive law development - Assessment of low triaxiality void nucleation models via extended finite element method

    Science.gov (United States)

    Zhao, Jifeng; Kontsevoi, Oleg Y.; Xiong, Wei; Smith, Jacob

    2017-05-01

    In this work, a multi-scale computational framework has been established in order to investigate, refine and validate constitutive behaviors in the context of the Gurson-Tvergaard-Needleman (GTN) void mechanics model. The eXtended Finite Element Method (XFEM) has been implemented in order to (1) develop statistical volume elements (SVE) of a matrix material with subscale inclusions and (2) to simulate the multi-void nucleation process due to interface debonding between the matrix and particle phases. Our analyses strongly suggest that under low stress triaxiality the nucleation rate of the voids f˙ can be well described by a normal distribution function with respect to the matrix equivalent stress (σe), as opposed to that proposed (σbar + 1 / 3σkk) in the original form of the single void GTN model. The modified form of the multi-void nucleation model has been validated based on a series of numerical experiments with different loading conditions, material properties, particle shape/size and spatial distributions. The utilization of XFEM allows for an invariant finite element mesh to represent varying microstructures, which implies suitability for drastically reducing complexity in generating the finite element discretizations for large stochastic arrays of microstructure configurations. The modified form of the multi-void nucleation model is further applied to study high strength steels by incorporating first principles calculations. The necessity of using a phenomenological interface separation law has been fully eliminated and replaced by the physics-based cohesive relationship obtained from Density Functional Theory (DFT) calculations in order to provide an accurate macroscopic material response.

  11. An Efficient Bypassing Void Routing Algorithm for Wireless Sensor Network

    Directory of Open Access Journals (Sweden)

    Xunli Fan

    2015-01-01

    Full Text Available Since the sensor node’s distribution in a wireless sensor network (WSN is irregular, geographic routing protocols using the greedy algorithm can cause local minima problem. This problem may fail due to routing voids and lead to failure of data transmission. Based on the virtual coordinate mapping, this paper proposes an efficient bypassing void routing protocol to solve the control packet overhead and transmission delay in routing void of WSN, which is called EBVRPVCM. The basic idea is to transfer the random structure of void edge to a regular one through mapping the coordinates on a virtual circle. In EBVRPVCM, some strategies, executed in different regions, are selected through virtual coordinates to bypass routing void efficiently. The regular edge is established by coordinate mapping that can shorten the average routing path length and decrease the transmission delay. The virtual coordinate mapping is not affected by the real geographic node position, and the control packet overhead can be reduced accordingly. Compared with RGP and GPSR, simulation results demonstrate that EBVRPVCM can successfully find the shortest routing path with higher delivery ratio and less control packet overhead and energy consumption.

  12. Electromigration of intergranular voids in metal films for microelectronic interconnects

    CERN Document Server

    Averbuch, A; Ravve, I

    2003-01-01

    Voids and cracks often occur in the interconnect lines of microelectronic devices. They increase the resistance of the circuits and may even lead to a fatal failure. Voids may occur inside a single grain, but often they appear on the boundary between two grains. In this work, we model and analyze numerically the migration and evolution of an intergranular void subjected to surface diffusion forces and external voltage applied to the interconnect. The grain-void interface is considered one-dimensional, and the physical formulation of the electromigration and diffusion model results in two coupled fourth-order one-dimensional time-dependent PDEs. The boundary conditions are specified at the triple points, which are common to both neighboring grains and the void. The solution of these equations uses a finite difference scheme in space and a Runge-Kutta integration scheme in time, and is also coupled to the solution of a static Laplace equation describing the voltage distribution throughout the grain. Since the v...

  13. Origin of the voids in the galaxy distribution

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, Y.; Shaham, J.

    1982-11-15

    The distribution of galaxies on scales larger than approx.10 h/sup -1/ Mpc seems to be characterized by large voids, (20--40) h/sup -1/ Mpc in diameter and of amplitude deltaapprox.-(0.7--0.8). It was previously argued that the mere existence of such voids poses a severe problem to all dissipationless clustering theories. Here we show that the voids may, in fact, be a natural outcome of a dissipationless clustering scenario if both adiabatic and isothermal density perturbations exist primordially. When the nonlinear evolution of spherical voids of this type is followed for adiabatic perturbations with an index n>-1, it is seen that they become surrounded by a shell of positive density contrast. Their structure is insensitive to ..cap omega../sub 0/ while their dynamics is quite sensitive to it. The maximum peculiar velocity (relative to Hubble flow) within the void is found to be: v/sub p//v/sub H/approx.(0.4--0.5) for ..cap omega../sub 0/ = 1.0, approx.(0.2--0.25) for ..cap omega../sub 0/ = 0.45, and < or approx. =0.09 for ..cap omega../sub 0/ = 0.1.

  14. Critical Void Volume Fraction fc at Void Coalescence for S235JR Steel at Low Initial Stress Triaxiality

    Science.gov (United States)

    Grzegorz Kossakowski, Paweł; Wciślik, Wiktor

    2017-10-01

    The paper is concerned with the nucleation, growth and coalescence of microdefects in the form of voids in S235JR steel. The material is known to be one of the basic steel grades commonly used in the construction industry. The theory and methods of damage mechanics were applied to determine and describe the failure mechanisms that occur when the material undergoes deformation. Until now, engineers have generally employed the Gurson-Tvergaard- Needleman model. This material model based on damage mechanics is well suited to define and analyze failure processes taking place in the microstructure of S235JR steel. It is particularly important to determine the critical void volume fraction fc , which is one of the basic parameters of the Gurson-Tvergaard-Needleman material model. As the critical void volume fraction fc refers to the failure stage, it is determined from the data collected for the void coalescence phase. A case of multi-axial stresses is considered taking into account the effects of spatial stress state. In this study, the parameter of stress triaxiality η was used to describe the failure phenomena. Cylindrical tensile specimens with a circumferential notch were analysed to obtain low values of initial stress triaxiality (η = 0.556 of the range) in order to determine the critical void volume fraction fc . It is essential to emphasize how unique the method applied is and how different it is from the other more common methods involving parameter calibration, i.e. curve-fitting methods. The critical void volume fraction fc at void coalescence was established through digital image analysis of surfaces of S235JR steel, which involved studying real, physical results obtained directly from the material tested.

  15. Nucleation of liquid droplets and voids in a stretched Lennard-Jones fcc crystal

    Science.gov (United States)

    Baidakov, Vladimir G.; Tipeev, Azat O.

    2015-09-01

    The method of molecular dynamics simulation has been used to investigate the phase decay of a metastable Lennard-Jones face-centered cubic crystal at positive and negative pressures. It is shown that at high degrees of metastability, crystal decay proceeds through the spontaneous formation and growth of new-phase nuclei. It has been found that there exists a certain boundary temperature. Below this temperature, the crystal phase disintegrates as the result of formation of voids, and above, as a result of formation of liquid droplets. The boundary temperature corresponds to the temperature of cessation of a crystal-liquid phase equilibrium when the melting line comes in contact with the spinodal of the stretched liquid. The results of the simulations are interpreted in the framework of classical nucleation theory. The thermodynamics of phase transitions in solids has been examined with allowance for the elastic energy of stresses arising owing to the difference in the densities of the initial and the forming phases. As a result of the action of elastic forces, at negative pressures, the boundary of the limiting superheating (stretching) of a crystal approaches the spinodal, on which the isothermal bulk modulus of dilatation becomes equal to zero. At the boundary of the limiting superheating (stretching), the shape of liquid droplets and voids is close to the spherical one.

  16. PEDAGOGIC CONDITIONS FOR IMPLEMENTATION OF THE MODEL OF FORMATION OF MORAL ORIENTATION IN CHILDREN YOUNGER WITH DEVIANT BEHAVIOR

    Directory of Open Access Journals (Sweden)

    Aldakusheva Evgenia Sergeevna

    2013-05-01

    Full Text Available In the Russian science and education policy are becoming increasingly recognizes the special role of the problems education of children, especially children "at risk." The main task of raising children "at risk" is the prevention of deviant behavior. The role of moral education of children in the prevention of deviant behavior is great because it helps prevent crime, neglect and delinquency, substance abuse prevention, enables to form the spiritual world (value orientation and the moral qualities of the child, allowing it to blend into society reveals the creative potential by expanding opportunities for career choice; forms diligence in work, promotes professional guidance, helping to reduce the number of unemployed, has a hard work (voluntary attitude toward work and honesty, reduces the number of dysfunctional families; solves the problem of social infantilism. Purpose: pick out pedagogic conditions implementation of model of formation of moral orientation children younger with deviant behavior. Methodology: simulation, system approach. Results: identified pedagogic conditions implementation of model of formation of moral orientation children younger with deviant behavior. Practical implications: education of children with behavioral problems.

  17. Internal Nano Voids in Yttria-Stabilised Zirconia (YSZ Powder

    Directory of Open Access Journals (Sweden)

    Chen Barad

    2017-12-01

    Full Text Available Porous yttria-stabilised zirconia ceramics have been gaining popularity throughout the years in various fields, such as energy, environment, medicine, etc. Although yttria-stabilised zirconia is a well-studied material, voided yttria-stabilised zirconia powder particles have not been demonstrated yet, and might play an important role in future technology developments. A sol-gel synthesis accompanied by a freeze-drying process is currently being proposed as a method of obtaining sponge-like nano morphology of embedded faceted voids inside yttria-stabilised zirconia particles. The results rely on a freeze-drying stage as an effective and simple method for generating nano-voided yttria-stabilised zirconia particles without the use of template-assisted additives.

  18. Toilet training method is not related to dysfunctional voiding.

    Science.gov (United States)

    Colaco, Marc; Johnson, Kelly; Schneider, Dona; Barone, Joseph

    2013-01-01

    Toilet training is an important marker of physical and psychosocial development, but the best strategy for implementing training is still unknown. The purpose of this study is to compare dysfunctional voiding outcomes for 2 common toilet training strategies: parent-oriented training and child-oriented training. This study was completed using a case-control design, with participants between the ages of 4 and 12 years. All participants were asked to complete questionnaires related to demographics and toilet training method. Results were then analyzed between cases and controls. In all, 215 patients with a mean age 7.76 years participated in this study. Cases and controls showed no significant difference for demographic measures and socioeconomic status. Furthermore, there was no significant difference in dysfunctional voiding between toilet training methods. Toilet training method does not seem to have any long-term effect on dysfunctional voiding. As such, clinicians should advise parents that both methods are acceptable.

  19. Tunnel and Subsurface Void Detection and Range to Target Measurement

    Energy Technology Data Exchange (ETDEWEB)

    Phillip B. West

    2009-06-01

    Engineers and technicians at the Idaho National Laboratory invented, designed, built and tested a device capable of detecting and measuring the distance to, an underground void, or tunnel. Preliminary tests demonstrated positive detection of, and range to, a void thru as much as 30 meters of top-soil earth. Device uses acoustic driving point impedance principles pioneered by the Laboratory for well-bore physical properties logging. Data receipts recorded by the device indicates constructive-destructive interference patterns characteristic of acoustic wave reflection from a downward step-change in impedance mismatch. Prototype tests demonstrated that interference patterns in receipt waves could depict the patterns indicative of specific distances. A tool with this capability can quickly (in seconds) indicate the presence and depth/distance of a void or tunnel. Using such a device, border security and military personnel can identify threats of intrusion or weapons caches in most all soil conditions including moist and rocky.

  20. Voids and constraints on nonlinear clustering of galaxies

    Science.gov (United States)

    Vogeley, Michael S.; Geller, Margaret J.; Park, Changbom; Huchra, John P.

    1994-01-01

    Void statistics of the galaxy distribution in the Center for Astrophysics Redshift Survey provide strong constraints on galaxy clustering in the nonlinear regime, i.e., on scales R equal to or less than 10/h Mpc. Computation of high-order moments of the galaxy distribution requires a sample that (1) densely traces the large-scale structure and (2) covers sufficient volume to obtain good statistics. The CfA redshift survey densely samples structure on scales equal to or less than 10/h Mpc and has sufficient depth and angular coverage to approach a fair sample on these scales. In the nonlinear regime, the void probability function (VPF) for CfA samples exhibits apparent agreement with hierarchical scaling (such scaling implies that the N-point correlation functions for N greater than 2 depend only on pairwise products of the two-point function xi(r)) However, simulations of cosmological models show that this scaling in redshift space does not necessarily imply such scaling in real space, even in the nonlinear regime; peculiar velocities cause distortions which can yield erroneous agreement with hierarchical scaling. The underdensity probability measures the frequency of 'voids' with density rho less than 0.2 -/rho. This statistic reveals a paucity of very bright galaxies (L greater than L asterisk) in the 'voids.' Underdensities are equal to or greater than 2 sigma more frequent in bright galaxy samples than in samples that include fainter galaxies. Comparison of void statistics of CfA samples with simulations of a range of cosmological models favors models with Gaussian primordial fluctuations and Cold Dark Matter (CDM)-like initial power spectra. Biased models tend to produce voids that are too empty. We also compare these data with three specific models of the Cold Dark Matter cosmogony: an unbiased, open universe CDM model (omega = 0.4, h = 0.5) provides a good match to the VPF of the CfA samples. Biasing of the galaxy distribution in the 'standard' CDM model

  1. Warmth Elevating the Depths: Shallower Voids with Warm Dark Matter

    OpenAIRE

    Yang, Lin F.; Neyrinck, Mark C.; Aragon-Calvo, Miguel A.; Falck, Bridget; Silk, Joseph

    2014-01-01

    Warm dark matter (WDM) has been proposed as an alternative to cold dark matter (CDM), to resolve issues such as the apparent lack of satellites around the Milky Way. Even if WDM is not the answer to observational issues, it is essential to constrain the nature of the dark matter. The effect of WDM on haloes has been extensively studied, but the small-scale initial smoothing in WDM also affects the present-day cosmic web and voids. It suppresses the cosmic "sub-web" inside voids, and the forma...

  2. The effects of void handling on geodetic mass balances

    Science.gov (United States)

    McNabb, Robert; Nuth, Chris; Kääb, Andreas; Girod, Luc

    2017-04-01

    Glacier mass balance is a direct expression of climate change, and has implications for changes in sea level, ocean chemistry, and oceanic and terrestrial ecosystems. Glacier mass balance has traditionally been measured through in-situ measurements of surface elevation change on a glacier surface. To estimate changes on a larger spatial scale, however, in-situ measurement is not feasible, and aerial or satellite measurements of digital elevation models (DEMs) over glaciers have been used recently in order to supplement and extend ground-based measurements. Though the resolution and accuracy of these products generally increases with time, there are still often gaps ("voids") in the data, as well as errors and biases that must be addressed. The occurrence and distribution of these voids is at least partially dependent on the sensor or acquisition method used to generate the source DEMs. For example, for optical stereo DEMs, voids can be especially frequent in the accumulation area of glaciers, impacting elevation measurements and the resulting estimates of glacier volume change to an unknown degree. Several methods for handling voids in elevation datasets have been proposed and implemented in the literature, though direct investigation of the uncertainty associated with these methods is generally not reported. In order to estimate the uncertainties associated with various methods for filling voids in elevation data, we simulate typical voids in high-resolution spatially-complete DEMs of glaciers in south-central Alaska (covering the Alaska Range, Chugach, Kenai, and Wrangel Mountains), USA. This region is home to over 7000 individual glaciers covering over 23000 km2, ranging in elevation from sea level to over 6000 m, and representing many different glacier types including surging glaciers, advancing and retreating tidewater glaciers, and large and small valley glaciers. As such, it presents an ideal test region to investigate the impact of various methods for void

  3. Segmentation and tracking of stem cells in time lapse microscopy to quantify dynamic behavioral changes during spheroid formation.

    Science.gov (United States)

    Jiang, Ching-Fen; Hsu, Shan-hui; Tsai, Ka-Pei; Tsai, Ming-Hong

    2015-06-01

    Dynamic behavior of stem cells during in vitro development is diverse. Previous cell tracking studies have focused more on cell proliferation than on cell aggregation. However, the enhancement of cell proliferation in association with cell aggregation has been reported. In a previous study, we also demonstrated that the aggregation of adult human mesenchymal stem cells to form three-dimensional (3D) cellular spheroids helped maintain the expression of stemness marker genes in the cells. However, the dynamic behavioral changes triggered by spheroid formation remain to be investigated. A scheme of image processing techniques is proposed to meet this need. A hybrid-thresholding technique was first developed for efficient segmentation of cell clusters, after which a cell tracking method based on pair-matching with topological constraints was designed. Two morphological indices were derived to track the timing of 3D spheroid formation during the cellular aggregation process. Five cell motility indices measured from single cells and 3D spheroids were then compared. After confirmation of more than 90% correspondence between the results obtained by manual tracking and the proposed methods, an analysis of cellular behavior reveals a significant increase in motility in association with spheroid formation, consistent with a previous report that used a gene expression approach. This study proposed a systematic image analysis method to quantify the dynamic behavior of stem cells for stemness evaluation during cell culturing in vitro. Results demonstrated the validity of the developed platform in investigation of the dynamic behavior of cell aggregation in stem cell cultures in vitro. © 2015 International Society for Advancement of Cytometry.

  4. Behavioral and physiological changes during benthic-pelagic transition in the harmful alga, Heterosigma akashiwo: potential for rapid bloom formation.

    Directory of Open Access Journals (Sweden)

    Elizabeth D Tobin

    Full Text Available Many species of harmful algae transition between a motile, vegetative stage in the water column and a non-motile, resting stage in the sediments. Physiological and behavioral traits expressed during benthic-pelagic transition potentially regulate the timing, location and persistence of blooms. The roles of key physiological and behavioral traits involved in resting cell emergence and bloom formation were examined in two geographically distinct strains of the harmful alga, Heterosigma akashiwo. Physiological measures of cell viability, division and population growth, and cell fatty acid content were made using flow cytometry and gas chromatography - mass spectrometry techniques as cells transitioned between the benthic resting stage and the vegetative pelagic stage. Video-based tracking was used to quantify cell-level swimming behaviors. Data show increased temperature and light triggered rapid emergence from the resting stage and initiated cell swimming. Algal strains varied in important physiological and behavioral traits, including survivorship during life-stage transitions, population growth rates and swimming velocities. Collectively, these traits function as "population growth strategies" that can influence bloom formation. Many resting cells regained the up-swimming capacity necessary to cross an environmentally relevant halocline and the ability to aggregate in near-surface waters within hours after vegetative growth supporting conditions were restored. Using a heuristic model, we illustrate how strain-specific population growth strategies can govern the timescales over which H. akashiwo blooms form. Our findings highlight the need for identification and quantification of strain-specific physiological and behavioral traits to improve mechanistic understanding of bloom formation and successful bloom prediction.

  5. Influence of voids in the hybrid layer based on self-etching adhesive systems: a 3-D FE analysis.

    Science.gov (United States)

    Martini, Ana Paula; Anchieta, Rodolfo Bruniera; Rocha, Eduardo Passos; Freitas Junior, Amilcar Chagas; Almeida, Erika Oliveira de; Sundfeld, Renato Herman; Luersen, Marco Antonio

    2009-01-01

    The presence of porosities at the dentin/adhesive interface has been observed with the use of new generation dentin bonding systems. These porosities tend to contradict the concept that etching and hybridization processes occur equally and simultaneously. Therefore, the aim of this study was to evaluate the micromechanical behavior of the hybrid layer (HL) with voids based on a self-etching adhesive system using 3-D finite element (FE) analysis. Three FE models (Mr) were built: Mr, dentin specimen (41x41x82 μm) with a regular and perfect (i.e. pore-free) HL based on a self-etching adhesive system, restored with composite resin; Mp, similar to M, but containing 25% (v/v) voids in the HL; Mpp, similar to Mr, but containing 50% (v/v) voids in the HL. A tensile load (0.03N) was applied on top of the composite resin. The stress field was obtained by using Ansys Workbench 10.0. The nodes of the base of the specimen were constrained in the x, y and z axes. The maximum principal stress (σmax) was obtained for all structures at the dentin/adhesive interface. The Mpp showed the highest peak of σmax in the HL (32.2 MPa), followed by Mp (30 MPa) and Mr (28.4 MPa). The stress concentration in the peritubular dentin was high in all models (120 MPa). All other structures positioned far from voids showed similar increase of stress. Voids incorporated into the HL raised the σmax in this region by 13.5%. This behavior might be responsible for lower bond strengths of self-etching and single-bottle adhesives, as reported in the literature.

  6. Influence of voids in the hybrid layer based on self-etching adhesive systems: a 3-D FE analysis

    Directory of Open Access Journals (Sweden)

    Ana Paula Martini

    2009-01-01

    Full Text Available The presence of porosities at the dentin/adhesive interface has been observed with the use of new generation dentin bonding systems. These porosities tend to contradict the concept that etching and hybridization processes occur equally and simultaneously. Therefore, the aim of this study was to evaluate the micromechanical behavior of the hybrid layer (HL with voids based on a self-etching adhesive system using 3-D finite element (FE analysis. MATERIAL AND METHODS: Three FE models (Mr were built: Mr, dentin specimen (41x41x82 μm with a regular and perfect (i.e. pore-free HL based on a self-etching adhesive system, restored with composite resin; Mp, similar to M, but containing 25% (v/v voids in the HL; Mpp, similar to Mr, but containing 50% (v/v voids in the HL. A tensile load (0.03N was applied on top of the composite resin. The stress field was obtained by using Ansys Workbench 10.0. The nodes of the base of the specimen were constrained in the x, y and z axes. The maximum principal stress (σmax was obtained for all structures at the dentin/adhesive interface. RESULTS: The Mpp showed the highest peak of σmax in the HL (32.2 MPa, followed by Mp (30 MPa and Mr (28.4 MPa. The stress concentration in the peritubular dentin was high in all models (120 MPa. All other structures positioned far from voids showed similar increase of stress. CONCLUSION: Voids incorporated into the HL raised the σmax in this region by 13.5%. This behavior might be responsible for lower bond strengths of self-etching and single-bottle adhesives, as reported in the literature.

  7. Discovery of an extremely gas rich dwarf triplet near the centre of the Lynx-Cancer void

    Science.gov (United States)

    Chengalur, J. N.; Pustilnik, S. A.

    2013-01-01

    The Giant Metrewave Radio Telescope (GMRT) H i observations, done as part of an ongoing study of dwarf galaxies in the Lynx-Cancer void, resulted in the discovery of a triplet of extremely gas rich galaxies located near the centre of the void. The triplet members SDSS J0723+3621, SDSS J0723+3622 and SDSS J0723+3624 have absolute magnitudes MB of -14.2, -11.9 and -9.7 and M(H i)/LB of ˜2.9, ˜10 and ˜25, respectively. The gas mass fractions, as derived from the Sloan Digital Sky Survey (SDSS) photometry and the GMRT data, are 0.93, 0.997 and 0.997, respectively. The faintest member of this triplet, SDSS J0723+3624, is one of the most gas rich galaxies known. We find that all three galaxies deviate significantly from the Tully-Fisher relation, but follow the baryonic Tully-Fisher relation. All three galaxies also have a baryon fraction that is significantly smaller than the cosmic baryon fraction. For the largest galaxy in the triplet, this is in contradiction to numerical simulations. The discovery of this very unique dwarf triplet lends further support to the idea that the void environment is conducive to the formation of galaxies with unusual properties. These observations provide further motivation to do deep searches of voids for a `hidden' very gas rich galaxy population with MB ≳ -11.

  8. Simplifying the diagnosis of 4 common voiding conditions using uroflow/electromyography, electromyography lag time and voiding history.

    Science.gov (United States)

    Van Batavia, Jason P; Combs, Andrew J; Hyun, Grace; Bayer, Agnes; Medina-Kreppein, Daisy; Schlussel, Richard N; Glassberg, Kenneth I

    2011-10-01

    Noninvasive uroflowmetry with simultaneous electromyography is useful to triage cases of lower urinary tract symptoms into 4 urodynamically defined conditions, especially when incorporating short and long electromyography lag times in the analysis. We determined the prevalence of these 4 conditions at a single referral institution and the usefulness of uroflowmetry with simultaneous electromyography and electromyography lag time to confirm the diagnosis, guide treatment and monitor response. We retrospectively reviewed the records of 100 consecutive normal children who presented with persistent lower urinary tract symptoms, underwent uroflowmetry with electromyography as part of the initial evaluation and were diagnosed with 1 of 4 conditions based on certain uroflowmetry/electromyography features. The conditions included 1) dysfunctional voiding--active pelvic floor electromyography during voiding with or without staccato flow, 2a) idiopathic detrusor overactivity disorder-A--a quiet pelvic floor during voiding and shortened lag time (less than 2 seconds), 2b) idiopathic detrusor overactivity disorder-B--a quiet pelvic floor with a normal lag time, 3) detrusor underutilization disorder--volitionally deferred voiding with expanded bladder capacity but a quiet pelvic floor, and 4) primary bladder neck dysfunction--prolonged lag time (greater than 6 seconds) and a depressed, right shifted uroflowmetry curve with a quiet pelvic floor during voiding. Treatment was tailored to the underlying condition in each patient. The group consisted of 50 males and 50 females with a mean age of 8 years (range 3 to 18). Dysfunctional voiding was more common in females (p Electromyography lag time increased in idiopathic detrusor overactivity disorder-A cases and decreased in primary bladder neck dysfunction cases. Noninvasive uroflowmetry with simultaneous electromyography offers an excellent alternative to invasive urodynamics to diagnose 4 urodynamically defined conditions. It

  9. Comparative Analysis of CTF and Trace Thermal-Hydraulic Codes Using OECD/NRC PSBT Benchmark Void Distribution Database

    Directory of Open Access Journals (Sweden)

    M. Avramova

    2013-01-01

    Full Text Available The international OECD/NRC PSBT benchmark has been established to provide a test bed for assessing the capabilities of thermal-hydraulic codes and to encourage advancement in the analysis of fluid flow in rod bundles. The benchmark was based on one of the most valuable databases identified for the thermal-hydraulics modeling developed by NUPEC, Japan. The database includes void fraction and departure from nucleate boiling measurements in a representative PWR fuel assembly. On behalf of the benchmark team, PSU in collaboration with US NRC has performed supporting calculations using the PSU in-house advanced thermal-hydraulic subchannel code CTF and the US NRC system code TRACE. CTF is a version of COBRA-TF whose models have been continuously improved and validated by the RDFMG group at PSU. TRACE is a reactor systems code developed by US NRC to analyze transient and steady-state thermal-hydraulic behavior in LWRs and it has been designed to perform best-estimate analyses of LOCA, operational transients, and other accident scenarios in PWRs and BWRs. The paper presents CTF and TRACE models for the PSBT void distribution exercises. Code-to-code and code-to-data comparisons are provided along with a discussion of the void generation and void distribution models available in the two codes.

  10. 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.

  11. Electric field theory and the fallacy of void capacitance

    DEFF Research Database (Denmark)

    McAllister, Iain Wilson

    1991-01-01

    The concept of the capacitance of a gaseous void is discussed as applied to electrical insulation science. The most pertinent aspect of the capacitance definition is that of reference to a single-valued potential difference between surfaces. This implies that these surfaces must be surfaces...

  12. Efficacy of voided urinary cytology and ultrasonography compared to ...

    African Journals Online (AJOL)

    N. Kumar

    2017-07-29

    Jul 29, 2017 ... of bladder cancer was done. They were subjected to voided urinary cytology and ultrasonography. The results were compared with the inferences drawn from cystoscopy and histopathological examination of the resected tumor, wherever applicable. Results: The sensitivity of urinary cytology and ...

  13. Low-void polyimide resins for autoclave processing

    Science.gov (United States)

    Jones, R. J.; Vaughan, R. W.

    1972-01-01

    Development of an advanced A-type polyimide, which can be used to produce autoclave molded, low-void content composites suitable for use at temperatures up to 316 C is reported. It consists of a mixture of methyl nadic anhydride, an 80:20 molar ratio of methylene dianaline and thiodianilene, and pyromellitic dianhydride.

  14. The Aspen–Amsterdam Void Finder Comparison Project

    NARCIS (Netherlands)

    Colberg, J¨org M.; Pearce, Frazer; Foster, Caroline; Platen, Erwin; Brunino, Riccardo; Neyrinck, Mark; Basilakos, Spyros; Faira, Anthony; Feldman, Hume; Gottlöber, Stefan; Hahn, Oliver; Hoyle, Fiona; M¨uller, V.; Nelson, Lorne; Plionis, Manolis; Porciani, Cristiano; Shandarin, Sergei; Vogeley, Michael S.; Weygaert, Rien van de

    2008-01-01

    Despite a history that dates back at least a quarter of a century studies of voids in the large–scale structure of the Universe are bedevilled by a major problem: there exist a large number of quite different void–finding algorithms, a fact that has so far got in the way of groups comparing their

  15. Calculation of Void in the Fort Saint Vrain Material

    Energy Technology Data Exchange (ETDEWEB)

    Potter, David Charles [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Taylor, Craig Michael [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Coons, James Elmer [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-05-11

    The percent void of the Fort Saint Vrain (FSV) material is estimated to be 21.1% based on the volume of the gap at the top of the drums, the volume of the coolant channels in the FSV fuel element, and the volume of the fuel handling channel in the FSV fuel element.

  16. Efficacy of voided urinary cytology and ultrasonography compared to ...

    African Journals Online (AJOL)

    Introduction: Painless hematuria is the presenting symptom in 85–90% of patients with bladder cancer. Objectives: To evaluate the efficacy of voided urinary cytology and ultrasonography in the diagnosis and follow up of bladder cancer compared to cystoscopy as a gold standard with reference to its grade. To recommend a ...

  17. Void coalescence mechanism for combined tension and large amplitude cyclic shearing

    DEFF Research Database (Denmark)

    Nielsen, Kim Lau; Andersen, Rasmus Grau; Tvergaard, Viggo

    2017-01-01

    , imposed at the far boundary, is in an early state of the deformation associated with significant stretching of parts of the void surface, while other parts remain practically un-deformed. A largely uneven distribution of the strain hardening, therefore, evolves along the void circumference and, thus, one...... cannot expect the void to return to its original shape in the case where the far-field loading is reversed. The present numerical work aims to investigate the evolution of micro-voids subject to constant tension and large amplitude cyclic shearing. The far-field loading, the void shape, and the void...

  18. Discrete modelling of ductile crack growth by void growth to coalescence

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    2007-01-01

    Ductile crack growth is analyzed by discrete representation of the voids growing near a blunting crack-tip. Coalescence of the nearest void with the crack-tip is modeled, followed by the subsequent coalescence of other discretely represented voids with the newly formed crack-tip. Necking of the l......Ductile crack growth is analyzed by discrete representation of the voids growing near a blunting crack-tip. Coalescence of the nearest void with the crack-tip is modeled, followed by the subsequent coalescence of other discretely represented voids with the newly formed crack-tip. Necking...

  19. Constraints on Cosmology and Gravity from the Dynamics of Voids.

    Science.gov (United States)

    Hamaus, Nico; Pisani, Alice; Sutter, P M; Lavaux, Guilhem; Escoffier, Stéphanie; Wandelt, Benjamin D; Weller, Jochen

    2016-08-26

    The Universe is mostly composed of large and relatively empty domains known as cosmic voids, whereas its matter content is predominantly distributed along their boundaries. The remaining material inside them, either dark or luminous matter, is attracted to these boundaries and causes voids to expand faster and to grow emptier over time. Using the distribution of galaxies centered on voids identified in the Sloan Digital Sky Survey and adopting minimal assumptions on the statistical motion of these galaxies, we constrain the average matter content Ω_{m}=0.281±0.031 in the Universe today, as well as the linear growth rate of structure f/b=0.417±0.089 at median redshift z[over ¯]=0.57, where b is the galaxy bias (68% C.L.). These values originate from a percent-level measurement of the anisotropic distortion in the void-galaxy cross-correlation function, ϵ=1.003±0.012, and are robust to consistency tests with bootstraps of the data and simulated mock catalogs within an additional systematic uncertainty of half that size. They surpass (and are complementary to) existing constraints by unlocking cosmological information on smaller scales through an accurate model of nonlinear clustering and dynamics in void environments. As such, our analysis furnishes a powerful probe of deviations from Einstein's general relativity in the low-density regime which has largely remained untested so far. We find no evidence for such deviations in the data at hand.

  20. On the linearity of tracer bias around voids

    Science.gov (United States)

    Pollina, Giorgia; Hamaus, Nico; Dolag, Klaus; Weller, Jochen; Baldi, Marco; Moscardini, Lauro

    2017-07-01

    The large-scale structure of the Universe can be observed only via luminous tracers of the dark matter. However, the clustering statistics of tracers are biased and depend on various properties, such as their host-halo mass and assembly history. On very large scales, this tracer bias results in a constant offset in the clustering amplitude, known as linear bias. Towards smaller non-linear scales, this is no longer the case and tracer bias becomes a complicated function of scale and time. We focus on tracer bias centred on cosmic voids, i.e. depressions of the density field that spatially dominate the Universe. We consider three types of tracers: galaxies, galaxy clusters and active galactic nuclei, extracted from the hydrodynamical simulation Magneticum Pathfinder. In contrast to common clustering statistics that focus on auto-correlations of tracers, we find that void-tracer cross-correlations are successfully described by a linear bias relation. The tracer-density profile of voids can thus be related to their matter-density profile by a single number. We show that it coincides with the linear tracer bias extracted from the large-scale auto-correlation function and expectations from theory, if sufficiently large voids are considered. For smaller voids we observe a shift towards higher values. This has important consequences on cosmological parameter inference, as the problem of unknown tracer bias is alleviated up to a constant number. The smallest scales in existing data sets become accessible to simpler models, providing numerous modes of the density field that have been disregarded so far, but may help to further reduce statistical errors in constraining cosmology.

  1. Social Network Influence on Online Behavioral Choices: Exploring Group Formation on Social Network Sites

    OpenAIRE

    Kwon, KH; Stefanone, MA; Barnett, GA

    2014-01-01

    Social media communication is characterized by reduced anonymity and off-to-online social interactions. These characteristics require scholars to revisit social influence mechanisms online. The current study builds on social influence literature to explore social network and gender effects on online behavior. Findings from a quasi-experiment suggest that both network-related variables and gender are significantly associated with online behavior. Perceived social environment, measured by perso...

  2. Voids and superstructures: correlations and induced large-scale velocity flows

    Science.gov (United States)

    Lares, Marcelo; Luparello, Heliana E.; Maldonado, Victoria; Ruiz, Andrés N.; Paz, Dante J.; Ceccarelli, Laura; Garcia Lambas, Diego

    2017-09-01

    The expanding complex pattern of filaments, walls and voids build the evolving cosmic web with material flowing from underdense on to high density regions. Here, we explore the dynamical behaviour of voids and galaxies in void shells relative to neighbouring overdense superstructures, using the Millenium simulation and the main galaxy catalogue in Sloan Digital Sky Survey data. We define a correlation measure to estimate the tendency of voids to be located at a given distance from a superstructure. We find voids-in-clouds (S-types) preferentially located closer to superstructures than voids-in-voids (R-types) although we obtain that voids within ˜40 h-1 Mpc of superstructures are infalling in a similar fashion independently of void type. Galaxies residing in void shells show infall towards the closest superstructure, along with the void global motion, with a differential velocity component depending on their relative position in the shell with respect to the direction to the superstructure. This effect is produced by void expansion and therefore is stronger for R-types. We also find that galaxies in void shells facing the superstructure flow towards the overdensities faster than galaxies elsewhere at the same relative distance to the superstructure. The results obtained for the simulation are also reproduced for the Sky Survey Data Release data with a linearized velocity field implementation.

  3. Family Structure History: Links to Relationship Formation Behaviors in Young Adulthood

    Science.gov (United States)

    Ryan, Suzanne; Franzetta, Kerry; Schelar, Erin; Manlove, Jennifer

    2009-01-01

    Using data from three waves of the National Longitudinal Study of Adolescent Health (N = 4,667), we examined the intergenerational link between parental family structure history and relationship formation in young adulthood. We investigated (a) whether parental family structure history is associated with young adults' own relationship formation…

  4. Criminality and family formation: Effects of marriage and parenthood on criminal behavior for men and women

    NARCIS (Netherlands)

    Zoutewelle-Terovan, M.V.; van der Geest, V.R.; Liefbroer, A.C.; Bijleveld, C.C.J.H.

    2014-01-01

    In this article, the authors study the effects of family formation on criminal careers for 540 high-risk men and women in the Netherlands. In a prospective design, spanning 21 years, the authors analyzed complete data on offending, marriage, parenthood, and a large set of background information.

  5. Randomized controlled trial of a cognitive-behavioral motivational intervention in a group versus individual format for substance use disorders.

    Science.gov (United States)

    Sobell, Linda Carter; Sobell, Mark B; Agrawal, Sangeeta

    2009-12-01

    Although group therapy is widely used for individuals with substance use disorders (SUDs), randomized clinical trials (RCTs) comparing the same treatment in a group versus individual format are rare. This paper presents the results of a RCT comparing guided self-change (GSC) treatment, a cognitive-behavioral motivational intervention, conducted in a group versus individual format with 212 alcohol abusers and 52 drug abusers who voluntarily sought outpatient treatment. Treatment outcomes demonstrated significant and large reductions in clients' alcohol and drug use during treatment and at the 12-month follow-up, with no significant differences between the group and individual therapy conditions. A therapist time ratio analysis found that it took 41.4% less therapist time to treat clients using the group versus the individual format. Participants' end-of-treatment group cohesion scores characterized the groups as having high engagement, low levels of interpersonal conflict, and low avoidance of group work, all desirable group characteristics. These findings suggest that the GSC treatment model was effectively integrated into a brief group treatment format. Health care cost containment compels further evaluations of the efficacy of group treatments for SUDs. Copyright 2009 APA

  6. Oral Cancer Risk Behaviors among Indiana College Students: A Formative Research Study

    Science.gov (United States)

    Raychowdhury, Swati; Lohrmann, David K.

    2008-01-01

    Objectives: In fall 2004, the authors used a survey to assess the knowledge, attitudes, motivations, and behaviors of college students relative to oral cancer prevention to inform development of targeted prevention programming. Participants: A convenience sample of 1,003 undergraduate students at one public university in Indiana participated.…

  7. Reflecting and Assimilation and contrast in impression formation and automatic behavior.

    NARCIS (Netherlands)

    Dijksterhuis, A.; Spears, R.; Lepinasse, V.

    2001-01-01

    Factors influencing the tendency to represent a social stimulus primarily in stereotypic terms, or more as a distinct exemplar, were predicted to moderate automatic behavior effects, producing assimilation and contrast respectively. In Exp 1, the authors demonstrated that when an impression

  8. Pedagogical Formation Students' Resistance Behaviors towards Teaching-Learning Processes and Their Moral Maturity

    Science.gov (United States)

    Argon, Türkan; Sezen-Gültekin, Gözde

    2016-01-01

    Moral maturity, defined as the competence in moral emotions, thoughts, judgments, attitudes and behaviors, is one of the most important qualities that the would-be teachers at Faculties of Education must possess. Teachers with moral maturity will train students with the qualities of reliability, responsibility, fairness, objectivity, consistency…

  9. Anion-Dependent Aggregate Formation and Charge Behavior of Colloidal Fullerenes (n-C60)

    Science.gov (United States)

    The fate and transport of colloidal fullerenes (n-C60) in the environment is likely to be guided by electrokinetic and aggregation behavior. In natural water bodies inorganic ions exert significant effects in determining the size and charge of n-C60 nanoparticles. Although the ef...

  10. Prevention of Addictive Behavior Based on the Formation of Teenagers' Resilience

    Science.gov (United States)

    Zeleeva, Vera P.; Shubnikova, Ekaterina G.

    2016-01-01

    The relevance of the study is due to the development of a new stage of prevention and the need to justify new educational goals and objectives of the pedagogical prevention of addictive behavior in the educational environment. The purpose of this article is to examine the totality of the necessary and sufficient individual resources, that are…

  11. Critical Role of the Spacer Length of Gemini Surfactants on the Formation of Ionic Liquid Crystals and Thermotropic Behavior.

    Science.gov (United States)

    Fernandes, Ricardo M F; Wang, Yujie; Tavares, Pedro B; Nunes, Sandra C C; Pais, Alberto A C C; Marques, Eduardo F

    2017-10-24

    Numerous reports have shown that the self-assembling properties of 12-s-12 bis(quaternary ammonium) gemini surfactants in aqueous solution are significantly influenced by s, the number of methylene groups in the covalent spacer. However, the role played by s on the phase behavior of the single compounds has not been investigated in a similarly systematic way. Here, we report on the thermotropic phase behavior of the anhydrous compounds with s = 2-6, 8, 10 and 12, resorting to differential scanning calorimetry (DSC), polarized light microscopy (PLM) and X-ray diffraction (XRD). All of the compounds show a stepwise melting behavior, decomposing at 200 ºC. As the spacer length increases non-monotonic trends are observed for the thermodynamic parameters of the thermotropic phase transitions, mesophase formation and solid-state d00l spacings. In particular, the number and type of mesophases (ordered smectic phases and/or fluid smectic liquid crystals) depend critically on s. Further, upon heating molecules with s < 8 decompose before the liquid phase, while those with long spacers, s = 8-12, reach the isotropization (clearing) temperature hence forming both ionic liquid crystals and ionic liquid phases. We demonstrate that the melting behavior and type of ionic mesophases formed by gemini molecules can be usefully manipulated by a simple structural parameter like the length of the covalent linker.

  12. Structure and phase formation behavior and dielectric and magnetic properties of lead iron tantalate-lead zirconate titanate multiferroic ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Wongmaneerung, R., E-mail: re_nok@yahoo.com [Faculty of Science, Maejo University, Chiang Mai 50290 (Thailand); Tipakontitikul, R. [Department of Physics, Ubonratchathani University, Ubonratchathani 31490 (Thailand); Jantaratana, P. [Department of Physics, Kasetsart University, Bangkok 10900 (Thailand); Bootchanont, A.; Jutimoosik, J.; Yimnirun, R. [School of Physics, Institute of Science, and NANOTEC-SUT Center of Excellence on Advanced Functional Nanomaterials, Suranaree University of Technology, Nakhon Ratchasima 30000 (Thailand); Ananta, S. [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)

    2016-03-15

    Highlights: • The multiferroic ceramics consisted of PFT and PZT. • Crystal structure changed from cubic to mixedcubic and tetragonal with increasing PZT content. • Dielectric showed the samples underwent a typical relaxor ferroelectric behavior. • Magnetic properties showed very interesting behavior with square saturated magnetic hysteresis loops. - Abstract: Multiferroic (1 − x)Pb(Fe{sub 0.5}Ta{sub 0.5})O{sub 3}–xPb(Zr{sub 0.53}Ti{sub 0.47})O{sub 3} (or PFT–PZT) ceramics were synthesized by solid-state reaction method. The crystal structure and phase formation of the ceramics were examined by X-ray diffraction (XRD). The local structure surrounding Fe and Ti absorbing atoms was investigated by synchrotron X-ray Absorption Near-Edge Structure (XANES) measurement. Dielectric properties were studied as a function of frequency and temperature using a LCR meter. A vibrating sample magnetometer (VSM) was used to determine the magnetic hysteresis loops. XRD study indicated that the crystal structure of the sample changed from pure cubic to mixed cubic and tetragonal with increasing PZT content. XANES measurements showed that the local structure surrounding Fe and Ti ions was similar. Dielectric study showed that the samples underwent a typical relaxor ferroelectric behavior while the magnetic properties showed very interesting behavior with square saturated magnetic hysteresis loops.

  13. A molecular dynamics study of void initiation and growth in monocrystalline and nanocrystalline copper

    OpenAIRE

    Traiviratana, Sirirat

    2008-01-01

    MD simulations in monocrystalline and nanocrystalline copper were carried out with LAMMPS to reveal void growth mechanisms. The specimens were subjected to both tensile uniaxial and hydrostatic strains; the results confirm that the emission of (shear) loops is the primary mechanism of void growth. The expansion of the loops and their cross slip leads to the severely work hardened layer surrounding a growing void. Calculations were carried out on voids with different sizes, and a size dependen...

  14. Challenges in the management of gas voids in safety related systems

    Energy Technology Data Exchange (ETDEWEB)

    Ezekoye, L.I.; Turkowski, W.M.; Ferraraccio, F.P.; Swartz, M.M. [Westinghouse Electric Company LLC, Pittsburgh (United States)

    2009-04-15

    Gas intrusion into Safety Related Systems, such as the Emergency Core Cooling System (ECCS), Decay Heat Removal (DHR) and Containment Spray (CS) in nuclear power plants is undesirable and can lead to pump binding (depending on the void fraction and flow rate) and damaging water hammer events. Gas ingestion in pumps can result in total or momentary loss of hydraulic performance resulting in possible pump shaft seizure rendering the pumps unable to perform their safety functions or reduce the pump discharge pressure and flow capacity to the point that the system cannot perform its design function. Extreme cases of gas water hammer can result in physical damage to system piping, components and supports, and possible relief valve lifting events with consequential loss of inventory. NRC Generic Letter GL 2008 01, 'Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems,' requires US utilities to demonstrate that suitable design, operational and testing measures are in place to maintain licensing commitments. The Generic Letter (GL 2008 01) outlines a number of actions that are detailed in nature, such as establishing pump void tolerance limits; establishing limits on pump suction void fractions, assuring adequate system venting capability, identification of all possible sources of gas intrusion, preventing vortex formation in tanks, and determining acceptable limits of gas in system discharge piping.. Regarding one of these issues, GL 2008 01 indicates that the amount of gas that can be ingested without significant impact on pump design, gas dispersion and flow rate. Each US nuclear power plant licensee is required to evaluate their ECCS, DHR and CS system design, operation and test procedures to assure that gas intrusion is minimized and monitored in order to maintain system operability and compliance with the requirements of 10 CFR 50 Appendix B. Typically, gas pockets get into the safety related systems through

  15. The Influence of the Presence of Multiple Voids on the Discharge Patterns in Solid Epoxy Insulation

    DEFF Research Database (Denmark)

    Holbøll, Joachim T.; Henriksen, Mogens; Larsen, Esben

    1996-01-01

    In this paper, partial discharge test results from initial long term testing on samples which contain more voids, when exposed to a high electric stress will be presented. The influence on the discharge patterns, phase- and height-analyses, of such parameter as the number of voids and the void di...

  16. 21 CFR 888.3045 - Resorbable calcium salt bone void filler device.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Resorbable calcium salt bone void filler device. 888.3045 Section 888.3045 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... salt bone void filler device. (a) Identification. A resorbable calcium salt bone void filler device is...

  17. Laboratory and exterior decay of wood plastic composite boards: voids analysis and computed tomography

    Science.gov (United States)

    Grace Sun; Rebecca E. Ibach; Meghan Faillace; Marek Gnatowski; Jessie A. Glaeser; John Haight

    2016-01-01

    After exposure in the field and laboratory soil block culture testing, the void content of wood–plastic composite (WPC) decking boards was compared to unexposed samples. A void volume analysis was conducted based on calculations of sample density and from micro-computed tomography (microCT) data. It was found that reference WPC contains voids of different sizes from...

  18. influence of orientation and size of voids on concrete cube strength

    African Journals Online (AJOL)

    Dr Obe

    25°, 35°, 45° to the horizontal axis of as-cast face of hollow concrete cubes were investigated. Analysis of the four grades of concrete studied showed that both void orientation and size of voids have influence on the uniaxial compressive strength of hollow concrete cubes. It showed that 45° void orientation has the highest ...

  19. Elastic–plastic void expansion in near-self-similar shapes

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    2011-01-01

    For void growth in an elastic–plastic strain hardening material the preferred shape of the void is calculated, dependent on the macroscopic stress state. Axisymmetric cell model analyses are carried out with a very small initial void size relative to the cell dimensions. Large deformations of the...

  20. Modelling the void deformation and closure by hot forging of ingot castings

    DEFF Research Database (Denmark)

    Christiansen, Peter; Hattel, Jesper Henri; Kotas, Petr

    2012-01-01

    . The analysis concernsboth the void density change and the location of the voids in the part after deformation. The latter can be important for the subsequent reliability of the parts, for instance regarding fatigue properties. The analysis incorporates the Gurson yield criterion for metals containing voids...

  1. Perineal Surface Electromyography Does Not Typically Demonstrate Expected Relaxation During Normal Voiding

    Science.gov (United States)

    Kirby, Anna C.; Nager, Charles W.; Litman, Heather J.; FitzGerald, Mary P.; Kraus, Stephen; Norton, Peggy; Sirls, Larry; Rickey, Leslie; Wilson, Tracey; Dandreo, Kimberly J.; Shepherd, Jonathan; Zimmern, Philippe

    2015-01-01

    Aims To describe perineal surface patch electromyography (EMG) activity during urodynamics (UDS) and compare activity between filling and voiding phases and to assess for a relationship between preoperative EMG activity and postoperative voiding symptoms. Methods 655 women underwent standardized preoperative UDS that included perineal surface EMG prior to undergoing surgery for stress urinary incontinence. Pressure-flow studies were evaluated for abdominal straining and interrupted flow. Quantitative EMG values were extracted from 10 predetermined time-points and compared between fill and void. Qualitative EMG activity was assessed for the percent of time EMG was active during fill and void and for the average amplitude of EMG during fill compared to void. Postoperative voiding dysfunction was defined as surgical revision or catheterization more than 6 weeks after surgery. Fisher’s exact test with a 5% two-sided significance level was used to assess differences in EMG activity and postoperative voiding dysfunction. Results 321 UDS had interpretable EMG studies, of which 131 (41%) had EMG values at all 10 predetermined and annotated time-points. Quantitative and qualitative EMG signals during flow were usually greater than during fill. The prevalence of postoperative voiding dysfunction in subjects with higher preoperative EMG activity during void was not significantly different. Results were similar in the 42 subjects who had neither abdominal straining during void nor interrupted flow. Conclusions Perineal surface patch EMG did not measure expected pelvic floor and urethral sphincter relaxation during voiding. Preoperative EMG did not predict patients at risk for postoperative voiding dysfunction. PMID:21560157

  2. 42 CFR 457.216 - Treatment of uncashed or canceled (voided) CHIP checks.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 4 2010-10-01 2010-10-01 false Treatment of uncashed or canceled (voided) CHIP... canceled (voided) CHIP checks. (a) Purpose. This section provides rules to ensure that States refund the... section— Canceled (voided) check means an CHIP check issued by a State or fiscal agent that prior to its...

  3. Coastal Meringues: Are Salt Marshes Inflated with Excess Void Spaces?

    Science.gov (United States)

    Gunnell, J. R.

    2016-02-01

    Failure to stay above sea level is among many ways that salt marshes may be destroyed. This race against the sea is carried out by vertical accretion. Accretion is partly the accumulation of material mediated by vegetative and sedimentary feedbacks. Prognoses for salt marshes based on studies of these variables have proven useful, but they may also be failing to read between the lines. After all, the majority of a salt marsh's volume is typically comprised of void spaces, which seem to be under-examined in our current predictions of salt marsh survival. Salt marshes may be inflated with excess void spaces, occupying greater volumes than sedimentary predictions would otherwise assume. To test this hypothesis, benthic porosity measurements were drawn from a USGS database of thousands of seabed samples along the U.S. Atlantic and Gulf coasts. Seabed porosities were used to geostatistically interpolate expected porosities at selected salt marsh sites. Measurements of known salt marsh porosities were drawn from several case studies in the literature. These salt marsh porosity measurements were georeferenced so they could be compared to the expected seabed porosity determined by spatial interpolation. Initial results show that these salt marshes tend to be more porous than the benthic sediments surrounding them. This excess porosity can be an important contributor to marsh volume (i.e. elevation), and ultimately to marsh survival. Furthermore, it raises several questions about the source of this void space and the mechanism of its retention. Salt marsh volume appears to be greater than we would expect based on the sum of its parts. Therefore, predictions of salt marsh accretion may systematically underestimate void volumes and be overly pessimistic about marsh response to relative sea level rise.

  4. Development of Improved Connection Details for Voided Slab Bridges

    OpenAIRE

    Joyce, Patrick Conor

    2014-01-01

    Adjacent voided slab bridges (AVSB) are economical systems for short spans. They provide the advantages of having low clearances due to their small section depths, accelerated construction times, and high torsional stiffness. The current longitudinal connection detail, a partial depth grouted shear key, has been known to fail in many of these bridges. The failure leads to reflective cracking in the wearing surface which allows chloride laden water to seep down through the joint, where it c...

  5. Influence of regenerator void volume on performance of a precooled 4 K Stirling type pulse tube cryocooler

    Science.gov (United States)

    Li, Zhuopei; Jiang, Yanlong; Gan, Zhihua; Qiu, Limin; Chen, Jie

    2015-09-01

    Stirling type pulse tube cryocoolers (SPTC), typically operating at 30-60 Hz, have the advantage of compact structure, light weight, and long life compared with Gifford-McMahon type (1-2 Hz) PTC (GMPTC). The behavior of flow and heat transfer in the regenerator of a 4 K SPTC deviates from that at warmer temperatures and low frequencies. In this paper the behavior of 4 K regenerator at high frequencies is investigated based on a single-stage 4 K SPTC precooled by a two-stage GMPTC. The 4 K SPTC and the GMPTC is thermally coupled with two thermal bridges. The 4 K SPTC uses a 10 K cold inertance tube as phase shifter to improve phase relationship between mass flow and pressure. The regenerator void volume is an important factor that significantly influences the heat transfer between regenerator matrix and working fluid helium, pressure drop along the regenerator, and phase shift between mass flow and pressure. In this paper, influence of regenerator void volume on the performance of the 4 K SPTC with different operating parameters including operating frequencies and average pressure is studied theoretically and experimentally. The first and second precooling powers provided by the GMPTC are obtained which are important parameters to evaluate the efficiency of the whole 4 K system with precooling. The results of the regenerator void volume are given and discussed in normalized form for general use.

  6. Multipole analysis of redshift-space distortions around cosmic voids

    Science.gov (United States)

    Hamaus, Nico; Cousinou, Marie-Claude; Pisani, Alice; Aubert, Marie; Escoffier, Stéphanie; Weller, Jochen

    2017-07-01

    We perform a comprehensive redshift-space distortion analysis based on cosmic voids in the large-scale distribution of galaxies observed with the Sloan Digital Sky Survey. To this end, we measure multipoles of the void-galaxy cross-correlation function and compare them with standard model predictions in cosmology. Merely considering linear-order theory allows us to accurately describe the data on the entire available range of scales and to probe void-centric distances down to about 2 h-1Mpc. Common systematics, such as the Fingers-of-God effect, scale-dependent galaxy bias, and nonlinear clustering do not seem to play a significant role in our analysis. We constrain the growth rate of structure via the redshift-space distortion parameter β at two median redshifts, β(bar z=0.32)=0.599+0.134-0.124 and β(bar z=0.54)=0.457+0.056-0.054, with a precision that is competitive with state-of-the-art galaxy-clustering results. While the high-redshift constraint perfectly agrees with model expectations, we observe a mild 2σ deviation at bar z=0.32, which increases to 3σ when the data is restricted to the lowest available redshift range of 0.15

  7. Piezoelectric performance of fluor polymer sandwiches with different void structures

    Science.gov (United States)

    Lou, Kexing; Zhang, Xiaoqing; Xia, Zhongfu

    2012-06-01

    Film sandwiches, consisting of two outer layers of fluoroethylenepropylene and one middle layer of patterned porous polytetrafluoroethylene, were prepared by patterning and fusion bonding. Contact charging was conducted to render the films piezoelectric. The critical voltage to trigger air breakdown in the inner voids in the fabricated films was investigated. The piezoelectric d 33 coefficients were measured employing the quasistatic method and dielectric resonance spectrum. The results show that the critical voltage for air breakdown in the inner voids is associated with the void microstructure of the films. For the films with patterning factors of 0%, 25% and 44%, the critical values are 300, 230 and 230 kV/cm, respectively. With an increase in the patterning factor, both the piezoelectric d 33 coefficients determined from the dielectric resonance spectra and those determined from quasistatic measurements increase, which might be due to a decrease in Young's modulus for the films. The nonlinearity of d 33 becomes increasingly obvious as the patterning factor increases.

  8. Meandering flow void around the splenium in moyamoya disease.

    Science.gov (United States)

    Mikami, Takeshi; Kuribara, Tomoyoshi; Komatsu, Katsuya; Kimura, Yusuke; Wanibuchi, Masahiko; Houkin, Kiyohiro; Mikuni, Nobuhiro

    2017-08-01

    Meandering flow void around the splenium, which can be recognized on conventional T2-weighted images, implicates collateral flow in the splenial artery in patients with moyamoya disease. In this report, curves of flow voids around the splenium (SFVs) were evaluated in patients with moyamoya disease, and their diagnostic value and pathophysiology were verified. A total of 65 consecutive patients with moyamoya disease were included in this analysis. The number of SFV curves was counted on each side. The numbers of SFV curves in patients with moyamoya disease was compared with those in the control group. The clinical features of patients with large numbers of flow voids were analyzed. The mean number of SFVs was significantly higher in the moyamoya disease group than in the control group or the atherosclerotic disease group. The cut-off SFV count for a diagnosis of moyamoya disease should be set to 2.25 in consideration of receiver operating characteristic curve analysis. A multivariate logistic analysis of SFV data in moyamoya disease revealed significant differences between the high SFV count group (≥2.25) and the low SFV count group (moyamoya disease. Increased number of SFV curves was associated with age and progress of disease.

  9. Effects of Heterogeneous Sink Distribution on Void Swelling

    DEFF Research Database (Denmark)

    Leffers, Torben; Volobuyev, A. V.; Gann, V. V.

    1986-01-01

    Swelling rates are calculated for two types of material with heterogeneous distributions of dislocations and voids, namely copper irradiated with neutrons to low dose at 250 degree C and heavily cold-worked copper irradiated with 1 MeV electrons in a HVEM at 250 degree C. Both materials are consi......Swelling rates are calculated for two types of material with heterogeneous distributions of dislocations and voids, namely copper irradiated with neutrons to low dose at 250 degree C and heavily cold-worked copper irradiated with 1 MeV electrons in a HVEM at 250 degree C. Both materials...... are considered to consist of non-interacting spherical components with a wall and an inner cell with different dislocation and/or void densities. We subdivide the sphere (wall plus cell) in a number of concentric shells and find a quasi-static solution for the interstitial and vacancy concentrations...... in the different shells by a finite-difference method. From these concentrations the local and the average swelling rate and the dependence of this effect of the heterogeneities in sink distribution on swelling rate and the dependence of this effect on various structural parameters are investigated....

  10. Phase behavior, formation, and rheology of cubic phase and related gel emulsion in Tween 80/water/oil systems.

    Science.gov (United States)

    Alam, Mohammad Mydul; Ushiyama, Kousuke; Aramaki, Kenji

    2009-01-01

    We investigated the phase behavior, formation, and rheology of the cubic phase (I(1)) and related O/I(1) gel emulsion in water/Tween 80/oil systems using squalane, liquid paraffin (LP), and decane as oil components. In the phase behavior study, the phase sequences were similar for squalane and LP systems, while a lamellar liquid crystal (L(alpha)) was observed for decane system. In all the systems the addition of oil to W(m) or H(1) phase induced the I(1) phase, which can solubilize some amounts of oil followed by the appearance of I(1)+O phase. The formation of the O/I(1) gel emulsion has been studied at a fixed w/s (50/50) and we found that 30 wt% decane, 70 wt% squalane, and 60 wt% LP can form the gel emulsion. The water/Tween 80/squalane system has been taken as a model system to study viscoelastic properties of the I(1) phase and O/I(1) gel emulsion. The I(1) phase shows a typical hard gel cubic structure under the frequency and the values of the complex viscosity, /eta*/ and the elastic modulus, G ' increase with the addition of squalane, which could be due to the neighboring micellar interaction. On the other hand, the decreasing values of the viscoelastic parameters in the O/I(1) gel emulsion simply relate to the volume fraction of the I(1) phase in the system.

  11. Coarse analysis of collective behaviors: Bifurcation analysis of the optimal velocity model for traffic jam formation

    Science.gov (United States)

    Miura, Yasunari; Sugiyama, Yuki

    2017-12-01

    We present a general method for analyzing macroscopic collective phenomena observed in many-body systems. For this purpose, we employ diffusion maps, which are one of the dimensionality-reduction techniques, and systematically define a few relevant coarse-grained variables for describing macroscopic phenomena. The time evolution of macroscopic behavior is described as a trajectory in the low-dimensional space constructed by these coarse variables. We apply this method to the analysis of the traffic model, called the optimal velocity model, and reveal a bifurcation structure, which features a transition to the emergence of a moving cluster as a traffic jam.

  12. Effect of initial void shape on ductile failure in a shear field

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    2015-01-01

    For voids in a shear field unit cell model analyses have been used to show that ductile failure is predicted even though the stress triaxiality is low or perhaps negative, so that the void volume fraction does not grow during deformation. Here, the effect of the void shape is studied by analyzing...... with circular cross-section, i.e. the voids in shear flatten out to micro-cracks, which rotate and elongate until interaction with neighboring micro-cracks gives coalescence. Even though the mechanism of ductile failure is the same, the load carrying capacity predicted, for the same initial void volume fraction...

  13. Formation of the Ability to Identify the Causes of Deviant Behavior among Adolescents in Students of Pedagogical High School

    Directory of Open Access Journals (Sweden)

    Busarova O.R.,

    2014-11-01

    Full Text Available The aim of the presented research was the development and testing of special exercises for the formation of skills to competently determine the causes of deviant behavior among adolescents during psychology classes in students of pedagogical high school. The study involved 23 students of 2nd grade at Moscow State Pedagogical University. Methodological basis for students training were the results of studies carried out in line with the concept of psychological diagnosis by A.F. Anufriev. The focus of the proposed exercises is the diagnostic hypotheses production, because in previous studies it was noted that this step of the diagnostic search is of the greatest difficulty for teachers. The efficiency of the developed exercises was evaluated by the quality of the problems solution proposed by the students to assess the causes of deviant behavior of middle school students. According to the study, we concluded that the exercises proposed to pedagogical high school students increase quality of solving problems and can significantly reduce the number of errors inherent in the activities of teachers to determine the causes of the behavior of students.

  14. Physics Study of Canada Deuterium Uranium Lattice with Coolant Void Reactivity Analysis

    Directory of Open Access Journals (Sweden)

    Jinsu Park

    2017-02-01

    Full Text Available This study presents a coolant void reactivity analysis of Canada Deuterium Uranium (CANDU-6 and Advanced Canada Deuterium Uranium Reactor-700 (ACR-700 fuel lattices using a Monte Carlo code. The reactivity changes when the coolant was voided were assessed in terms of the contributions of four factors and spectrum shifts. In the case of single bundle coolant voiding, the contribution of each of the four factors in the ACR-700 lattice is large in magnitude with opposite signs, and their summation becomes a negative reactivity effect in contrast to that of the CANDU-6 lattice. Unlike the coolant voiding in a single fuel bundle, the 2 × 2 checkerboard coolant voiding in the ACR-700 lattice shows a positive reactivity effect. The neutron current between the no-void and voided bundles, and the four factors of each bundle were analyzed to figure out the mechanism of the positive coolant void reactivity of the checkerboard voiding case. Through a sensitivity study of fuel enrichment, type of burnable absorber, and moderator to fuel volume ratio, a design strategy for the CANDU reactor was suggested in order to achieve a negative coolant void reactivity even for the checkerboard voiding case.

  15. Physics study of Canada deuterium uranium lattice with coolant void reactivity analysis

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jin Su; Lee, Hyun Suk; Tak, Tae Woo; Lee, Deok Jung [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of); Shin, Ho Cheol [Korea Hydro and Nuclear Power Central Research Institute (KHNP-CRI), Daejeon (Korea, Republic of)

    2017-02-15

    This study presents a coolant void reactivity analysis of Canada Deuterium Uranium (CANDU)-6 and Advanced Canada Deuterium Uranium Reactor-700 (ACR-700) fuel lattices using a Monte Carlo code. The reactivity changes when the coolant was voided were assessed in terms of the contributions of four factors and spectrum shifts. In the case of single bundle coolant voiding, the contribution of each of the four factors in the ACR-700 lattice is large in magnitude with opposite signs, and their summation becomes a negative reactivity effect in contrast to that of the CANDU-6 lattice. Unlike the coolant voiding in a single fuel bundle, the 2 x 2 checkerboard coolant voiding in the ACR-700 lattice shows a positive reactivity effect. The neutron current between the no-void and voided bundles, and the four factors of each bundle were analyzed to figure out the mechanism of the positive coolant void reactivity of the checkerboard voiding case. Through a sensitivity study of fuel enrichment, type of burnable absorber, and moderator to fuel volume ratio, a design strategy for the CANDU reactor was suggested in order to achieve a negative coolant void reactivity even for the checkerboard voiding case.

  16. Combined functional pelvic floor muscle exercises with Swiss ball and urotherapy for management of dysfunctional voiding in children: a randomized clinical trial.

    Science.gov (United States)

    Ladi Seyedian, Seyedeh Sanam; Sharifi-Rad, Lida; Ebadi, Maryam; Kajbafzadeh, Abdol-Mohammad

    2014-10-01

    We report the clinical results of two types of urotherapy programs in children with dysfunctional voiding (DV). Sixty children with a median age of 8 (range, 5-14) diagnosed with DV were randomly allocated to one of two groups, each made up of 30 patients. Patients in group A underwent behavioral urotherapy (hydration, scheduled voiding, toilet training, and high-fiber diet) combined with pelvic floor muscle (PFM) exercises, whereas group B only received behavioral urotherapy. All parents completed a voiding and bowel habit diary chart. Uroflowmetry with pelvic floor surface electromyography (EMG) and bladder ultrasound were performed on all patients at the beginning and the end of the 1-year study. Abnormal voiding pattern normalized to a bell shape in 21/30 of patients in group A and 8/30 of patients in group B (P Swiss ball combined with behavioral urotherapy proved as a safe and effective therapeutic modality, reducing the frequency of urinary incontinence, PVR, and the severity of constipation in children with DV.

  17. Equilibrium phase behavior and self-assembly dynamics of an SALR model of microphase formation

    Science.gov (United States)

    Charbonneau, Patrick; Zhuang, Yuan

    Colloidal models with short-range attraction and long-range repulsion (SALR) assemble into a rich set of equilibrium periodic microphases, including cluster crystal, cylindrical, double gyroid and lamellar phases. We present the phase diagram of such an SALR system obtained using specialized Monte Carlo-based methods. Remarkably, we find that even in the disordered regime, the model exhibits rich structural crossovers, which gives rise to a complex sequence of dynamical regimes. The dynamics notably depends on the formation and percolation of mesoscale cavities. We also consider the ease with which periodic microphases self-assemble, which we use to provide guidance for the design of colloidal experiments to reliably obtain such structures. We acknowledge support from National Science Foundation Grant NSF DMR-1055586 and from the Materials Research Science and Engineering Centers (NSF DMR-1121107).

  18. Ultra-small and anionic starch nanospheres: formation and vitro thrombolytic behavior study.

    Science.gov (United States)

    Huang, Yinjuan; Ding, Shenglong; Liu, Mingzhu; Gao, Chunmei; Yang, Jinlong; Zhang, Xinjie; Ding, Bin

    2013-07-25

    This paper is considered as the first report on the investigation of nattokinase (NK) release from anionic starch nanospheres. The ultra-small and anionic starch nanospheres were prepared by the method of reverse micro-emulsion crosslinking in this work. Starch nanospheres were characterized through Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and dynamic light scattering (DLS). Effects of preparation conditions on particle size were studied. The cytotoxicity, biodegradable and vitro thrombolytic behaviors of nattokinase (NK) loaded anionic starch nanospheres were also studied. The results showed that the anionic starch nanospheres are non-toxic, biocompatible and biodegradable. Moreover, the anionic starch nanospheres can protect NK from fast biodegradation hence prolongs the circulation in vivo and can reduce the risk of acute hemorrhage complication by decreasing the thrombolysis rate. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. An in vivo study on bone formation behavior of microporous granular calcium phosphate.

    Science.gov (United States)

    Dalmônico, G M L; Franczak, P F; Levandowski, N; Camargo, N H A; Dallabrida, A L; da Costa, B D; Gil, O García; Cambra-Moo, O; Rodríguez, M A; Canillas, M

    2017-06-27

    This study was developed based on in vivo investigation of microporous granular biomaterials based on calcium phosphates, involving matrices of β-tricalcium phosphate (β-TCP), hydroxyapatite (HA), biphasic compositions of both phases and a control group. The physicochemical characterization of materials was carried out by X-Ray diffraction (DRX) and mercury porosimetry. Biodegradability, bioactivity and neoformation processes were investigated by Raman spectroscopy, scanning electron microscopy (SEM) and polarized light conducted on biopsies obtained from in vivo tests for periods of 90 and 180 days. These were performed to evaluate the behavior of granular microporous compositions in relation to bone neoformation. Through the performance obtained from in vivo assays, excellent osseointegration and bone tissue neoformation were observed. The results are encouraging and show that the microporous granular biomaterials of HA, β-TCP and biphasic compositions show similar results with perfect osseointegration. Architectures simulating a bone structure can make the difference between biomaterials for bone tissue replacement and repair.

  20. Ages and Metallicities of Early-Type Void Galaxies from Line Strength Measurements

    Science.gov (United States)

    Wegner, Gary; Grogin, Norman A.

    2008-07-01

    We present spectroscopic observations of 26 galaxies of type E and S0, based on their blue morphologies, located in voids by the study of Grogin & Geller in 1999. Measurements of redshift, velocity dispersion, and four Lick line indices, Mg b , Fe5270, Fe5335, and Hβ with their errors are given for all of these galaxies, along with Hβ, [O III], Hα, and [N II] emission line strengths for a subset of these objects. These sources are brighter than M* for low-density regions and tend to be bluer than their counterpart early-type objects in high-density regions. Using the models of Thomas et al., developed in 2003, gives metal abundances and ages with a median α enhancement, [α/Fe] = +0.13, and median metal abundance, [Z/H] = +0.22, values comparable to those found for E and S0 galaxies in clusters, but with a wider spread in [Z/H] toward low values. If the emission line subsample is interpreted as younger, the proportion of young objects is higher than for early types in higher-density regions. There is a significant incidence of sources in the sample with emission lines in their spectra (46% with Hβ and [O III] and 69% with Hα or [N II]) as well as shells and rings in their morphologies (19%). The diagnostic log [{N\\,\\mathsc{ii}}]/ H\\alpha, log [{O\\,\\mathsc{iii}}]/ H\\beta diagram places 10 of 12 emission line galaxies in or near the star-forming and liner region and two among the Seyferts. The Hα fluxes indicate star-formation rates of 0.2-1.0 M sun yr-1. The percentage of these early-type void galaxies undergoing star formation appears to be higher compared to their cluster counterparts and the range of ages wider.

  1. Prediction of Average Void Fraction and Pdf of Void Fraction in Vertical 90o Bend for Air–Silicone Oil Flow Using Multilayer Perceptron (MLP Codes

    Directory of Open Access Journals (Sweden)

    Paul Onubi Ayegba

    2016-12-01

    Full Text Available Multilayer Perceptron (MLP models have been developed to predict twophase average void fraction and probability density function (PDF of void fraction in 90o bends. The Artificial Neural Network (ANN methodology was reported using MLP trained with 2 algorithms. Logarithmic sigmoid transfer function was used in a single hidden layer for both algorithms (Gradient descent (GDMV and Levenberg-Marquardt (LM algorithms. Both MLP models were optimised by varying the number of neurons in the hidden layer while monitoring the Mean Square Error (MSE. The performance of the models was evaluated using the Average Absolute Relative Error (AARE and Cross Correlation Coefficient (R. Both MLP models developed for the prediction of average void faction before the bend performed excellently well. However, the MLP model trained with LM algorithm having 3 neurons in the hidden layer gave better performance. Similarly, the MLP model trained with LM algorithm, having 11 neurons in the hidden layer for the prediction of PDF of void fraction before the bend gave excellent prediction. Model performance for the MLP models after the bend gave poor generalisation property. However, the MLP model based on GDMV algorithm gave better prediction for predicting average void fraction and PDF of void fraction after the bend. It was concluded that MLP models may with some confidence be used to predict the average void fraction and the PDFs of void fraction observed before a vertical 90o bend

  2. Manipulations in hydrogel degradation behavior enhance osteoblast function and mineralized tissue formation.

    Science.gov (United States)

    Benoit, Danielle S W; Durney, Andrew R; Anseth, Kristi S

    2006-06-01

    Hydrogels were prepared by copolymerizing a degradable macromer, poly(lactic acid)-b-poly(ethylene glycol)-b-poly(lactic acid) endcapped with methacrylate groups (PEG-LA-DM), with a nondegradable macromer, poly(ethylene glycol) dimethacrylate (PEGDM). Copolymer networks consisted of 100:0, 83:17, 67:33, and 50:50 PEGDM:PEG-LA-DM mass%, essentially creating scaffolds that exhibit 0, 17, 33, and 50% degradation over the time course of the experiment. Osteoblasts were photoencapsulated in these copolymer hydrogels and cultured for 3 weeks in vitro. Metabolic activity, proliferation, and alkaline phosphatase production were enhanced by an increase PEG-LADM content and corresponding degradation. Gene expression of the cultured osteoblasts, normalized to beta-actin, was analyzed, and osteopontin and collagen type I gene expression increased with degradation. Finally, as a measure of mineralized tissue formation, calcium and phosphate deposition was analyzed biochemically and histologically. Mineralization increased with increasing concentration of PEG-LA-DM and biochemically resembled that of hydroxyapatite.

  3. Study on weld pool behaviors and ripple formation in dissimilar welding under pulsed laser

    Science.gov (United States)

    Liang, Rong; Luo, Yu

    2017-08-01

    A three-transient numerical model is developed to study the dissimilar metal welding under pulsed laser. The melting, resolidification and vaporization inducing recoil pressure are considered in this model. Their effects on molten pool dynamic and the weld bead formation are studied. The similar metal welding and dissimilar metal welding under pulsed laser are respectively simulated by using this model. It is found that surface ripples are caused mainly by the periodical laser and molten pool solidification. In the first, this model is validated by the weld bead geometry comparison between the simulated and experimental results in similar metal welding. Then, this model is applied to simulate the dissimilar metal welding under pulsed laser. The results show that the distributions of the temperature, melt-flow velocity and surface ripples are asymmetric due to the differences in physical properties of the materials. The higher pulse overlapping factor decreases the solidification rate, leading to the more uniform penetration depths and the finer ripples. Good agreements between the experimental observations and simulation results are obtained by the proposed model.

  4. Formation, Crystallization Behavior, and Soft Magnetic Properties of FeCSiBP Bulk Metallic Glass Fabricated Using Industrial Raw Materials

    Science.gov (United States)

    Li, H. X.; Gao, J. E.; Wang, S. L.; Yi, S.; Lu, Z. P.

    2012-08-01

    Formation of pseudo-binary Fe-C-Si-B-P bulk metallic glasses (BMGs) with good glass-forming ability (GFA) and soft magnetic properties prepared using industrial pig-iron and P-Fe alloys as raw materials was investigated. It was found that the GFA could be enhanced by tuning the content of carbon, and fully glassy rods with a maximum diameter of 2 mm were obtained in the Fe77.3C5.9Si3.3B4.8P8.7 alloy. The crystallization behavior and its effects on the soft magnetic properties of the Fe77.3C5.9Si3.3B4.8P8.7 alloy were analyzed. The superior magnetic properties, coupled with large GFA and low cost of raw materials, make the current Fe-based BMGs promising for potential applications in electric industries.

  5. Towards a cosmological exploitation of cosmic void statistics - New numerical tools in the CosmoBolognaLib to extract cosmological constraints from the void size function

    Science.gov (United States)

    Ronconi, Tommaso; Marulli, Federico

    2017-03-01

    We present new numerical tools to analyse cosmic void catalogues, implemented inside the CosmoBolognaLib, a large set of Open Source C++/Python numerical libraries. The CosmoBolognaLib provides a common numerical environment for cosmological calculations. This work extends these libraries by adding new algorithms for cosmological analyses of cosmic voids, covering the existing gap between theory and observations. We implemented new methods to model the size function of cosmic voids, in both observed and simulated samples of dark matter and biased tracers. Moreover, we provide new numerical tools to construct unambiguous void catalogues. The latter are designed to be independent of the void finder, in order to allow a high versatility in comparing independent results. The implemented Open Source software is available at the GitHub repository https://github.com/federicomarulli/CosmoBolognaLib. We provide also a full doxygen documentation and some example codes that explain how to use these libraries.

  6. Informing a Behavior Change Communication Strategy: Formative Research Findings From the Scaling Up Nutrition Movement in Mozambique.

    Science.gov (United States)

    Kodish, Stephen; Aburto, Nancy; Dibari, Filippo; Brieger, William; Agostinho, Saozinha P; Gittelsohn, Joel

    2015-09-01

    Nutrition interventions targeting the first 1000 days show promise to improve nutritional status, but they require effective implementation. Formative research is thus invaluable for developing such interventions, but there have been few detailed studies that describe this phase of work within the Scaling Up Nutrition (SUN) movement. To inform a stunting prevention intervention in Cabo Delgado, Mozambique, by describing the sociocultural landscape and elucidating characteristics related to young child food, illness, and health. This formative research utilized a rapid assessment procedures (RAP) approach with 3 iterative phases that explored local perceptions and behaviors around food and illness among the Macua, Mwani, and Maconde ethnic groups. Ethnographic methods, including in-depth interviews, direct observations, free lists, and pile sorts, were used to collect data from community leaders, caregivers, and children 6 to 23 months. Data were analyzed drawing from grounded theory and cultural domain analysis. Geographic differences drive sociocultural characteristics amid 3 ethnic groups that allow for segmentation of the population into 2 distinct audiences for behavior change communications. These 2 communities have similar classification systems for children's foods but different adult dietary patterns. Small-quantity lipid-based nutrient supplement did not fall into the existing food classification systems of either community, and participants preferred its promotion through community leader channels. Community members in both groups have little recognition of and perceived severity toward nutrition-related illnesses. Within Cabo Delgado, the cultural heterogeneity yields substantial differences related to food, illness, and health that are necessary to consider for developing an effective nutrition intervention. © The Author(s) 2015.

  7. Topology and dark energy: testing gravity in voids.

    Science.gov (United States)

    Spolyar, Douglas; Sahlén, Martin; Silk, Joe

    2013-12-13

    Modified gravity has garnered interest as a backstop against dark matter and dark energy (DE). As one possible modification, the graviton can become massive, which introduces a new scalar field--here with a Galileon-type symmetry. The field can lead to a nontrivial equation of state of DE which is density and scale dependent. Tension between type Ia supernovae and Planck could be reduced. In voids, the scalar field dramatically alters the equation of state of DE, induces a soon-observable gravitational slip between the two metric potentials, and develops a topological defect (domain wall) due to a nontrivial vacuum structure for the field.

  8. Decay of charge deposited on the wall of gaseous void

    DEFF Research Database (Denmark)

    McAllister, Iain Wilson

    1992-01-01

    constant, the decay can take a considerable amount of time. The decay rate is significantly reduced by an increase in the permittivity of the bulk medium. The dominating influence of this permittivity is likewise reflected in the increased duration and thereby prolonged inhomogeneity of the electric field...... sustained in the void. However, the absolute value of this field is reduced with an increase in bulk permittivity. It is concluded that the present choice of a point charge to simulate the wall charge has the disadvantage that such a source is associated with a field singularity, and thus it is not possible...

  9. Dependence on supernovae light-curve processing in void models

    Energy Technology Data Exchange (ETDEWEB)

    Bengochea, Gabriel R., E-mail: gabriel@iafe.uba.ar [Instituto de Astronomía y Física del Espacio (IAFE), UBA-CONICET, CC 67, Suc. 28, 1428 Buenos Aires (Argentina); De Rossi, Maria E., E-mail: derossi@iafe.uba.ar [Instituto de Astronomía y Física del Espacio (IAFE), UBA-CONICET, CC 67, Suc. 28, 1428 Buenos Aires (Argentina); Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (Argentina)

    2014-06-02

    In this work, we show that when supernova Ia (SN Ia) data sets are used to put constraints on the free parameters of inhomogeneous models, certain extra information regarding the light-curve fitter used in the supernovae Ia luminosity fluxes processing should be taken into account. We found that the size of the void as well as other parameters of these models might be suffering extra degenerations or additional systematic errors due to the fitter. A recent proposal to relieve the tension between the results from Planck satellite and SNe Ia is re-analyzed in the framework of these subjects.

  10. Tarina kaiken takana : tarinallisuuden merkitys lyhytdokumentissa Hearing Void

    OpenAIRE

    Heinonen, Nina-Maria

    2014-01-01

    Opinnäytetyön kirjallinen osio käsittelee dokumenttielokuvan teoriaa yleisellä tasolla ja syventyy kysymykseen, miten dokumenttielokuva vaikuttaa katsojaan tarinallisuuden avulla. Käsittelen aihetta ja suunnittelu-, kuvaus- ja jälkityövaiheita opinnäytetyöni tuoteosan Hearing Void -lyhytdokumentin kautta. Dokumenttielokuvan teossa oleellista on ymmärtää keinot, joilla pyritään vaikuttamaan katsojaan. Fiktiosta poiketen dokumenttielokuvat todentavat ympäröivää maailmaa pyrkien esittämään...

  11. Effect of methylcellulose on the formation and drug release behavior of silk fibroin hydrogel.

    Science.gov (United States)

    Park, Cho Hee; Jeong, Lim; Cho, Donghwan; Kwon, Oh Hyeong; Park, Won Ho

    2013-10-15

    In this study, methylcellulose (MC) was used to control the gelation time of silk fibroin (SF) aqueous solution. The gelation time was measured using a Vibro Viscometer at 50 °C. Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and a texture meter were used to investigate the effect of MC on the hydrogelation of SF solution. SF/MC hydrogels could be formed by the addition of MC, although their gelation time was increased with MC content. To examine the conformational change of SF/MC hydrogels, time-resolved FT-IR spectra were obtained at constant temperature using a custom-made IR chamber. From FT-IR spectra focused on the amide I peak position, the transition of SF molecules in SF/MC solution from a random coil to a β-sheet structure was inhibited in the presence of MC molecules. In addition, the drug release of SF/MC hydrogels loaded with 5-aminosalicylic acid was studied in 2-dimensional (2-D) and 3-dimensional (3-D) conditions in vitro. The drug release behavior of SF or SF/MC hydrogels was measured using UV-Vis spectroscopy. The release rate of 5-aminosalicylic acid in SF/MC hydrogel was lower than that of SF hydrogel, which may be closely associated with the hydrophilic interaction between MC and 5-aminosalicylic acid. This approach to controlling the sol-gel transition and the drug release of SF hydrogels by the addition of MC will be useful in the design and tailoring of novel materials for biomedical applications. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Studies on chalcone derivatives: Complex formation, thermal behavior, stability constant and antioxidant activity

    Science.gov (United States)

    El-Sayed, Yusif S.; Gaber, M.

    2015-02-01

    The chalcone 3-[4‧-dimethylaminophenyl]-1-(2-pyridyl) prop-2-en-1-one (DMAPP) and 3-(4‧-diethylaminophenyl)-1-(2-pyridinyl) prop-2-en-1-one abbreviated as DEAPP have been synthesized and characterized with IR, 1H NMR, 13C NMR spectroscopic techniques as described previously (El-Daly et al., 2008; Gaber et al., 2009; El-Sayed, 2013). By using UV visible spectroscopy method the mole fraction ratio for copper with DMAPP and DEAPP complexes were determined and it was found to be 1:1. The stability constants of this complex have been determined by Job's method. The stability constant (Kf) of copper with DMAPP and DEAPP complexes in universal buffer pH = 3.2 was determined to be 9.9 × 104 and 5.2 × 104 respectively. The effect of Cu(II) ion on the emission spectrum of the free chalcone is also assigned. Adherence to Beer's law and Ringbom optimum concentration ranges are determined. The thermal decomposition of the metal complexes is studied by TGA technique. The kinetic parameters like activation energy, pre-exponential factor and entropy of activation are estimated. The structure of complexes was energetically optimized through molecular mechanics applying MM+ force field coupled with molecular dynamics simulation. The bond lengths and bond angles have been calculated to confirm the geometry of the ligands and their Cu(II) complexes. The mode of interaction of the chalcone to copper nanoparticles was studied. The apparent association constants of the colloidal copper nanoparticles:chalcone complexes in solution were evaluated using the spectral method and compared with the formation constant of the Cu(II) chalcone complexes. Antioxidant activity of these chalcones was evaluated by using 1,1‧-diphenyl-2-picrylhydrazyl (DPPHrad) radicals scavenging method, which showed that the antioxidant activity of DMAPP has higher value than the DEAPP. Semi-empirical study results showed that DMAPP have higher dipole moment than DEAPP [1].

  13. Observation On Void Formed In Oxide Scale Of Fe-Cr-Ni Alloy At 1073k In Dry And Humid Environments

    Directory of Open Access Journals (Sweden)

    Akbar Kaderi

    2012-01-01

    Full Text Available Void formation in oxide scale during high temperature oxidation is a common phenomenon. Over a long period of time voids will affect the mechanical property of scales by influencing the cracking and spalling. Voids formed in dry environment are different than that of formed in humid environment. With the presence of water vapor in humid environment the formation of void will increase, thus greater number of void compared to that in dry environment. Fe-Cr-Ni alloy samples were exposed isothermally at 1073 K in air (P_(O_2 = 0.21atm = 2.1×?10?^(5 Pa and  humid (air + steam environments. XRD analysis done to all samples confirms that Fe2O3, Fe3O4, NiCr2O4, FeCr2O4, Cr2O3 and NiO phases exist in the scale. EDX analysis done shows varying compositions of Fe,Cr,Ni and O in outer and inner oxide scale, oxide scale/metal interface and metal. Field emission scanning electron microscope (FE-SEM was used to investigate voids formed in the cross sections of the oxidized samples. Volume fraction of voids in the oxide scale was calculated in accordance to the cross sectional area fraction of voids in the scale. It shows that Fe-Cr-Ni alloy samples exposed in humid environment has as high as 71% more voids than that exposed in dry environment. It is concluded that the humid environment increased the number of void formed in the oxide scale, thus facilitates the exfoliation of protective scale during the high temperature oxidation. ABSTRAK: Pembentukan gelembung udara di dalam lapisan oksida ketika proses pengoksidaan di suhu tinggi merupakan satu fenomena biasa. Pada satu jangka masa yang panjang gelembung-gelembung ini akan memberi kesan kepada sifat mekanikal oksida dengan mempengaruhi pembentukan keretakan dan pengelupasan oksida. Gelembung udara yang terbentuk di dalam persekitaran kering berbeza daripada yang terbentuk di dalam persekitaran lembap. Dengan adanya wap air, pembentukan gelembung akan bertambah berbanding yang terbentuk di dalam

  14. Intermetallic Growth Induced Large-Scale Void Growth and Cracking Failure in Line-Type Cu/Solder/Cu Joints Under Current Stressing

    Science.gov (United States)

    Chen, Zhuo; Tian, Wenya; Li, Junhui; Zhu, Wenhui

    2018-01-01

    In order to study the electromigration (EM) behavior of solder joints in electronics packaging, especially under high-current and high-temperature working conditions, line-type Cu/solder/Cu butting samples were prepared to observe the microstructural evolution under 1.0 × 104 A/cm2 current stressing. A prominent polarity effect was found such that the Cu6Sn5 intermetallic compound (IMC) layer at the anode side, which thickened linearly with time, was much thicker than that at the cathode side. Compared to the samples subjected to thermal aging at the same temperature of 180°C, EM enhanced the Cu3Sn growth at both the anode and the cathode. Two distinct types of damage were observed after extended duration of current stressing. Back-flow of Cu into Cu3Sn was found at the Cu3Sn/Cu6Sn5 interface of the anode side, causing large voids, while strip cracks developed at the cathode solder/Cu6Sn5 interface, causing a significant increase of joint electrical resistance. With the mass transport characteristics that determine the IMC growth and vacancy accumulation analyzed in detail at each interface, formation mechanisms of the two types of damages are discussed.

  15. Formative Research to Study the Viewpoints, Attitudes and Driving Behaviors in Taxi Drivers of Yasuj: The First Step in Planning of an Intervention Based on Social Marketing Model

    Directory of Open Access Journals (Sweden)

    M Maleki

    2014-05-01

    Background & aim: Formative research is done to identify and analyze the related factors for a behavior and determining an initiative idea for intervention. This study aimed at knowing about viewpoints of taxi drivers in Yasuj and assessing attitudes and behaviors in driving. In this way, a behavioral intervention will be designed for decreasing risky driving behaviors. Methods: This cross-sectional study including qualitative and quantitative on taxi drivers in Yasuj. In qualitative part, data were explored from 16 drivers in two focal group discussions and in quantitative survey, a questionnaire is used for measuring attitudes and self-reported behaviors and a checklist is used for recording observational behaviors of 260 taxi drivers. Descriptive and analytical statistics for quantitative were used. All discussions with taxi drivers were recorded, categorized and analyzed and its findings summarized in five main themes. Results: Majority of taxi drivers had desired attitudes toward risky driving behaviors. More than 80 percent reported that always or most times avoid doing risky driving. However, observation showed that not fastening seatbelt through route is the most frequent behaviors among taxi drivers. In focal group discussions, four themes and few sub-themes were explored and the main recommendations for reducing risky driving behaviors were continuous education, road modification, increasing police supervision and using route supervisors as opinion leaders of taxi drivers. Conclusion: Determining frequent risky driving behaviors, attention to viewpoints of drivers and selecting segments based on influencing factors on their behaviors can be effective for reducing risky driving behaviors. Key words: Formative research, Risky driving behaviors, attitude, Taxi drivers, Social marketing

  16. One-Group Perturbation Theory Applied to Measurements with Void

    Energy Technology Data Exchange (ETDEWEB)

    Persson, Rolf

    1966-09-15

    Formulas suitable for evaluating progressive as well as single rod substitution measurements are derived by means of one-group perturbation theory. The diffusion coefficient may depend on direction and position. By using the buckling concept one can derive expressions which are quite simple and the perturbed flux can be taken into account in a comparatively simple way. By using an unconventional definition of cells a transition region is introduced quite logically. Experiments with voids around metal rods, diam. 3.05 cm, have been analysed. The agreement between extrapolated and directly measured buckling values is excellent, the buckling difference between lattices with water-filled and voided shrouds being 0. 263 {+-} 0.015/m{sup 2} and 0.267 {+-} 0.005/m{sup 2} resp. From single-rod experiments differences between diffusion coefficients are determined to {delta}D{sub r}/D = 0.083 {+-} 0.004 and {delta}D{sub z}/D = 0.120 {+-} 0.018. With air-filled shrouds there is consequently anisotropy in the neutron diffusion and we have (D{sub z}/D{sub r}){sub air} = 1.034 {+-} 0.020.

  17. Collapse and coalescence of spherical voids subject to intense shearing: studied in full 3D

    DEFF Research Database (Denmark)

    Nielsen, Kim Lau; Dahl, Jonas; Tvergaard, Viggo

    2012-01-01

    Micro-mechanical 2D cell model studies have revealed ductile failure during intense shearing to be governed by the interaction of neighbouring voids, which collapse to micro-cracks and continuously rotate and elongate until coalescence occurs. For a three-dimensional void structure, this implies...... significant straining of the matrix material located on the axis of rotation. In particular, the void surface material is severely deformed during shearing and void surface contact is established early in the deformation process. This 3D effect intensifies with decreasing stress triaxiality and complicates...... shape, void orientation etc. The objective of this work is to expand the range of stress triaxiality usually faced in 3D cell model studies, such that intense shearing is covered, and to bring forward details on the porosity and void shape evolution. The overall material response is presented...

  18. Improved model of redshift-space distortions around voids: Application to quintessence dark energy

    Science.gov (United States)

    Achitouv, Ixandra

    2017-10-01

    Using cosmic voids to probe the growth rate of cosmic structure, and hence the nature of dark energy, is particularly interesting in the context of modified gravity theories that rely on the "screening mechanism." In this work we improve the modelling of redshift-space distortions around voids in the dark matter density field, and thus reduce systematic errors in the derivation of cosmological parameters. We also show how specific types of voids can be used to better probe the growth rate, using a flexible void finder. We apply our results to test for a "quintessence" type of dark energy vs. a Λ CDM model, and find a good agreement with the fiducial cosmology after implementing an analytical correction to the radial velocity profiles around voids. We additionally outline characteristic imprints of dark energy in the dark matter velocity distributions around voids.

  19. Three-dimensional investigation of grain orientation effects on void growth in commercially pure titanium

    Energy Technology Data Exchange (ETDEWEB)

    Pushkareva, Marina [Department of Mechanical Engineering, University of Ottawa, 150 Louis Pasteur, Ottawa, ON, Canada K1N 6N5 (Canada); Adrien, Jérôme; Maire, Eric [Université de Lyon, INSA-Lyon, MATEIS CNRS UMR5510, 7 Avenue Jean Capelle, F-69621 Villeurbanne (France); Segurado, Javier; Llorca, Javier [IMDEA Materials Institute, C/Eric Kandel 2, 28906 Getafe, Madrid (Spain); Department of Materials Science, Polytechnic University of Madrid, E. T. S. de Ingenieros de Caminos, 28040 Madrid (Spain); Weck, Arnaud, E-mail: aweck@uottawa.ca [Department of Mechanical Engineering, University of Ottawa, 150 Louis Pasteur, Ottawa, ON, Canada K1N 6N5 (Canada); IMDEA Materials Institute, C/Eric Kandel 2, 28906 Getafe, Madrid (Spain); Department of Physics, University of Ottawa, 150 Louis Pasteur, Ottawa, ON, Canada K1N 6N5 (Canada); Centre for Research in Photonics at the University of Ottawa, 800 King Edward Ave., Ottawa, ON, Canada K1N 6N5 (Canada)

    2016-08-01

    The fracture process of commercially pure titanium was visualized in model materials containing artificial holes. These model materials were fabricated using a femtosecond laser coupled with a diffusion bonding technique to obtain voids in the interior of titanium samples. Changes in void dimensions during in-situ straining were recorded in three dimensions using x-ray computed tomography. Void growth obtained experimentally was compared with the Rice and Tracey model which predicted well the average void growth. A large scatter in void growth data was explained by differences in grain orientation which was confirmed by crystal plasticity simulations. It was also shown that grain orientation has a stronger effect on void growth than intervoid spacing and material strength. Intervoid spacing, however, appears to control whether the intervoid ligament failure is ductile or brittle.

  20. Dislocation mechanism of void growth at twin boundary of nanotwinned nickel based on molecular dynamics simulation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yanqiu; Jiang, Shuyong, E-mail: jiangshy@sina.com; Zhu, Xiaoming; Zhao, Yanan

    2016-08-12

    Molecular dynamics simulation was performed to investigate dislocation mechanism of void growth at twin boundary (TB) of nanotwinned nickel. Simulation results show that the deformation of nanotwinned nickel containing a void at TB is dominated by the slip involving both leading and trailing partials, where the trailing partials are the dissociation products of stair-rod dislocations formed by the leading partials. The growth of a void at TB is attributed to the successive emission of the leading partials followed by trailing partials as well as the escape of these partial dislocations from the void surface. - Highlights: • Dislocation mechanism of void growth at TB of nanotwinned nickel is investigated. • Deformation of the nanotwinned nickel is dominated by leading and trailing partials. • Growth of void at TB is caused by successive emission and escape of these partials.

  1. Fuzzy Reasoning to More Accurately Determine Void Areas on Optical Micrographs of Composite Structures

    Science.gov (United States)

    Dominquez, Jesus A.; Tate, Lanetra C.; Wright, M. Clara; Caraccio, Anne

    2013-01-01

    Accomplishing the best-performing composite matrix (resin) requires that not only the processing method but also the cure cycle generate low-void-content structures. If voids are present, the performance of the composite matrix will be significantly reduced. This is usually noticed by significant reductions in matrix-dominated properties, such as compression and shear strength. Voids in composite materials are areas that are absent of the composite components: matrix and fibers. The characteristics of the voids and their accurate estimation are critical to determine for high performance composite structures. One widely used method of performing void analysis on a composite structure sample is acquiring optical micrographs or Scanning Electron Microscope (SEM) images of lateral sides of the sample and retrieving the void areas within the micrographs/images using an image analysis technique. Segmentation for the retrieval and subsequent computation of void areas within the micrographs/images is challenging as the gray-scaled values of the void areas are close to the gray-scaled values of the matrix leading to the need of manually performing the segmentation based on the histogram of the micrographs/images to retrieve the void areas. The use of an algorithm developed by NASA and based on Fuzzy Reasoning (FR) proved to overcome the difficulty of suitably differentiate void and matrix image areas with similar gray-scaled values leading not only to a more accurate estimation of void areas on composite matrix micrographs but also to a faster void analysis process as the algorithm is fully autonomous.

  2. Glass composition and process for sealing void spaces in electrochemical devices

    Science.gov (United States)

    Meinhardt, Kerry D [Richland, WA; Kirby, Brent W [Kennewick, WA

    2012-05-01

    A glass foaming material and method are disclosed for filling void spaces in electrochemical devices. The glass material includes a reagent that foams at a temperature above the softening point of the glass. Expansion of the glass fills void spaces including by-pass and tolerance channels of electrochemical devices. In addition, cassette to cassette seals can also be formed while channels and other void spaces are filled, reducing the number of processing steps needed.

  3. Centimeter to decimeter hollow concretions and voids in Gale Crater sediments, Mars

    OpenAIRE

    Wiens, Roger C.; Rubin, David M.; Goetz, Walter; Fairén, Alberto G.; Schwenzer, Susanne P.; Johnson, Jeffrey R.; Milliken, Ralph; Clark, Ben; Mangold, Nicolas; Stack, Kathryn M.; Oehler, Dorothy; Rowland, Scott; Chan, Marjorie; Vaniman, David; Maurice, Sylvestre

    2017-01-01

    Voids and hollow spheroids between ∼1 and 23 cm in diameter occur at several locations along the traverse of the Curiosity rover in Gale crater, Mars. These hollow spherical features are significantly different from anything observed in previous landed missions. The voids appear in dark-toned, rough-textured outcrops, most notably at Point Lake (sols 302-305) and Twin Cairns Island (sol 343). Point Lake displays both voids and cemented spheroids in close proximity; other locations show one or...

  4. A theoretical derivation of the transients related to partial discharges in ellipsoidal voids

    DEFF Research Database (Denmark)

    Crichton, George C; Karlsson, A.; Pedersen, Aage

    1988-01-01

    Transients associated with partial discharges in ellipsoidal and spheroidal voids are derived in terms of the induced charges on the electrode. The relationship between the induced charge and the properties which are usually measured are discussed. Formulas are obtained from which conclusions can...... be drawn about the effects of the gas within the void as well as the size, shape, and location of voids. The method is illustrated by applying it to a spheroidal void in a simple disk-type gas-insulated-substation (GIS) spacer. It is found that the nonattaching gas generates an induced charge...

  5. Behaviorism

    National Research Council Canada - National Science Library

    Moore, J

    2011-01-01

    .... Watson proposed an alternative: classical S-R behaviorism. According to Watson, behavior was a subject matter in its own right, to be studied by the observational methods common to all sciences...

  6. Dynamic void distribution in myoglobin and five mutants

    Science.gov (United States)

    Jiang, Yingying; Kirmizialtin, Serdal; Sanchez, Isaac C.

    2014-02-01

    Globular proteins contain cavities/voids that play specific roles in controlling protein function. Elongated cavities provide migration channels for the transport of ions and small molecules to the active center of a protein or enzyme. Using Monte Carlo and Molecular Dynamics on fully atomistic protein/water models, a new computational methodology is introduced that takes into account the protein's dynamic structure and maps all the cavities in and on the surface. To demonstrate its utility, the methodology is applied to study cavity structure in myoglobin and five of its mutants. Computed cavity and channel size distributions reveal significant differences relative to the wild type myoglobin. Computer visualization of the channels leading to the heme center indicates restricted ligand access for the mutants consistent with the existing interpretations. The new methodology provides a quantitative measure of cavity structure and distributions and can become a valuable tool for the structural characterization of proteins.

  7. Dynamical 3-Space: Cosmic Filaments, Sheets and Voids

    Directory of Open Access Journals (Sweden)

    Cahill R. T.

    2011-04-01

    Full Text Available Observations of weak gravitational lensing combined with statistical tomographic techniques have revealed that galaxies have formed along filaments, essentially one- dimensional lines or strings, which form sheets and voids. These have, in the main, been interpreted as “dark matter” effects. To the contrary here we report the discovery that the dynamical 3-space theory possesses such filamentary solutions. These solutions are purely space self-interaction effects, and are attractive to matter, and as well gener- ate electromagnetic lensing. This theory of space has explained bore hole anomalies, supermassive black hole masses in spherical galaxies and globular clusters, flat rota- tion curves of spiral galaxies, and other gravitational anomalies. The theory has two constants, G and , where the bore hole experiments show that 1 = 137 is the fine structure constant.

  8. Truncated spherical voids for nearly omnidirectional optical absorption.

    Science.gov (United States)

    Wang, Min; Hu, Chenggang; Pu, Mingbo; Huang, Cheng; Zhao, Zeyu; Feng, Qin; Luo, Xiangang

    2011-10-10

    Truncated spherical voids nanostructured tungsten films are shown to have nearly perfect absorption with characteristics of broad-band, polarization-independent and wide-incidence angle in near infrared and visible regime. Through optimizing material and structural parameters, we can achieve the absorbance above 90% from 420THz to 600THz within incidence angle from 0° to 60° for TE polarization and from 450THz to 800THz within incidence angle from 0° to 75° for TM polarization. In particular, absorbance can achieve 99.9% at 550.5THz for both polarizations under normal incidence. Such strong absorption is explained using multilayer effective media theory and cavity resonance.

  9. Dynamical 3-Space: Cosmic Filaments, Sheets and Voids

    Directory of Open Access Journals (Sweden)

    Cahill R. T.

    2011-04-01

    Full Text Available Observations of weak gravitational lensing combined with statistical tomographic techniques have revealed that galaxies have formed along filaments, essentially one-dimensional lines or strings, which form sheets and voids. These have, in the main, been interpreted as "dark matter" effects. To the contrary here we report the discovery that the dynamical 3-space theory possesses such filamentary solutions. These solutions are purely space self-interaction effects, and are attractive to matter, and as well generate electromagnetic lensing. This theory of space has explained bore hole anomalies, supermassive black hole masses in spherical galaxies and globular clusters, flat rotation curves of spiral galaxies, and other gravitational anomalies. The theory has two constants, $G$ and $alpha$, where the bore hole experiments show that $alpha approx 1/137$ is the fine structure constant.

  10. Void fraction prediction of NUPEC PSBT tests by CATHARE code

    Energy Technology Data Exchange (ETDEWEB)

    Del Nevo, A. [ENEA UTIS-TCI, C.R. Brasimone (Italy); Michelotti, L.; Moretti, F.; Rozzia, D.; D' Auria, F. [Univ. of Pisa, Pisa (Italy)

    2011-07-01

    The current generation of thermal-hydraulic system codes benefits of about sixty years of experiments and forty years of development and are considered mature tools to provide best estimate description of phenomena and detailed reactor system representations. However, there are continuous needs for checking the code capabilities in representing nuclear system, for drawing attention to their weak points, for identifying models which need to be refined for best-estimate calculations. Prediction of void fraction and Departure from Nucleate Boiling (DNB) in system thermal-hydraulics is currently based on empirical approaches. The database carried out by Nuclear Power Engineering Corporation (NUPEC), Japan addresses these issues. It is suitable for supporting the development of new computational tools based on more mechanistic approaches (i.e. three-field codes, two-phase CFD, etc.) as well as for validating current generation of thermal-hydraulic system codes. Selected experiments belonging to this database are used for the OECD/NRC PSBT benchmark. The paper reviews the activity carried out by CATHARE2 code on the basis of the subchannel (four test sections) and presents rod bundle (different axial power profile and test sections) experiments available in the database in steady state and transient conditions. The results demonstrate the accuracy of the code in predicting the void fraction in different thermal-hydraulic conditions. The tests are performed varying the pressure, coolant temperature, mass flow and power. Sensitivity analyses are carried out addressing nodalization effect and the influence of the initial and boundary conditions of the tests. (author)

  11. 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)

  12. Interactions of hydrophobically modified polyvinylamines: adsorption behavior at charged surfaces and the formation of polyelectrolyte multilayers with polyacrylic acid.

    Science.gov (United States)

    Illergård, Josefin; Enarsson, Lars-Erik; Wågberg, Lars; Ek, Monica

    2010-02-01

    The structure and adsorption behaviors of two types of hydrophobically modified polyvinylamines (PVAm) containing substituents of hexyl and octyl chains were compared to a native polyvinylamine sample. The conformation of dissolved polyvinylamines was studied in aqueous salt solutions using dynamic light scattering. Modified PVAm showed hydrodynamic diameters similar to native PVAm, which indicated that all PVAm polymers were present as single molecules in solution. The adsorption of the polyvinylamines, both native and hydrophobically modified, from aqueous solution onto negatively charged silica surfaces was studied in situ by reflectometry and quartz crystal microgravimetry with dissipation. Polyelectrolyte multilayers (PEM) with up to nine individual layers were formed together with poly(acrylic acid). Obtained PEM structures were rigid and showed high adsorbed amounts combined with low dissipation, with similar results for both the modified and unmodified PVAm. This suggests that electrostatics dominated the PEM formation. At lower salt concentrations, the hydrophobically modified PVAm produced multilayers with low water contents, indicating that secondary interactions induced by the hydrophobic constituents can also have a significant influence on the properties of the formed layers. The surface structure of PEMs with nine individual layers was imaged in dry state using atomic force microscopy in a dynamic mode. Modified PVAm was found to induce a different structure of the PEM at 100 mM, with larger aggregates compared to those of native PVAm. From these results, it is proposed that modified PVAm can induce aggregation within the PEM, whereas PVAm remains as single molecules in solution.

  13. Pelvic floor muscle retraining for pediatric voiding dysfunction using interactive computer games.

    Science.gov (United States)

    McKenna, P H; Herndon, C D; Connery, S; Ferrer, F A

    1999-09-01

    We evaluated a new noninvasive outpatient method of pelvic muscle retraining in children using computer game assisted biofeedback. All patients in whom voiding dysfunction was confirmed by history, uroflowmetry-electromyography and voiding cystourethrography were enrolled in a pelvic floor muscle retraining program. Patients received a pretreatment, mid treatment and posttreatment survey instrument documenting subjective improvement, including the frequency of diurnal enuresis, nocturnal enuresis, constipation and encopresis. Pretreatment and posttreatment simultaneous uroflowmetry surface electrode electromyography was performed and post-void residual urine volume was determined in all patients. A total of 8 boys and 33 girls 5 to 11 years old (mean age 7.2) completed therapy and were available for evaluation. These patients completed 2 to 11 (average 6) hourly treatment sessions. Followup was 3 to 15 months (average 7). At the midterm evaluation improvement in nocturnal enuresis was reported by 57% of the patients, diurnal enuresis by 84%, constipation by 83% and encopresis by 91%. End treatment evaluation revealed improvement in nocturnal enuresis by 90% of patients, diurnal enuresis by 89%, constipation by 100% and encopresis by 100%. Uroflowmetry-electromyography patterns improved in 42% of the patients and post-void residual urine decreased in 57%. Comparison of initial to end recorded millivoltage pelvic floor muscle values demonstrated that 56% of the patients had lower resting tone at the beginning of the session after completing therapy and 78% had improved contracting tone after performing Kegel exercises, as proved by increased microvoltage values. Initial uroflowmetry-electromyography revealed certain categories of cases, including a flattened voiding curve with a hyperactive pelvic floor and low post-void residual urine in 40%, a flattened voiding curve with a hyperactive pelvic floor and high post-void residual urine in 40%, a staccato voiding curve

  14. LOG-NORMAL DISTRIBUTION OF COSMIC VOIDS IN SIMULATIONS AND MOCKS

    Energy Technology Data Exchange (ETDEWEB)

    Russell, E.; Pycke, J.-R., E-mail: er111@nyu.edu, E-mail: jrp15@nyu.edu [Division of Science and Mathematics, New York University Abu Dhabi, P.O. Box 129188, Abu Dhabi (United Arab Emirates)

    2017-01-20

    Following up on previous studies, we complete here a full analysis of the void size distributions of the Cosmic Void Catalog based on three different simulation and mock catalogs: dark matter (DM), haloes, and galaxies. Based on this analysis, we attempt to answer two questions: Is a three-parameter log-normal distribution a good candidate to satisfy the void size distributions obtained from different types of environments? Is there a direct relation between the shape parameters of the void size distribution and the environmental effects? In an attempt to answer these questions, we find here that all void size distributions of these data samples satisfy the three-parameter log-normal distribution whether the environment is dominated by DM, haloes, or galaxies. In addition, the shape parameters of the three-parameter log-normal void size distribution seem highly affected by environment, particularly existing substructures. Therefore, we show two quantitative relations given by linear equations between the skewness and the maximum tree depth, and between the variance of the void size distribution and the maximum tree depth, directly from the simulated data. In addition to this, we find that the percentage of voids with nonzero central density in the data sets has a critical importance. If the number of voids with nonzero central density reaches ≥3.84% in a simulation/mock sample, then a second population is observed in the void size distributions. This second population emerges as a second peak in the log-normal void size distribution at larger radius.

  15. Void probability as a function of the void's shape and scale-invariant models. [in studies of spacial galactic distribution

    Science.gov (United States)

    Elizalde, E.; Gaztanaga, E.

    1992-01-01

    The dependence of counts in cells on the shape of the cell for the large scale galaxy distribution is studied. A very concrete prediction can be done concerning the void distribution for scale invariant models. The prediction is tested on a sample of the CfA catalog, and good agreement is found. It is observed that the probability of a cell to be occupied is bigger for some elongated cells. A phenomenological scale invariant model for the observed distribution of the counts in cells, an extension of the negative binomial distribution, is presented in order to illustrate how this dependence can be quantitatively determined. An original, intuitive derivation of this model is presented.

  16. Correlation between quality of life and voiding variables in patients treated with percutaneous tibial nerve stimulation.

    NARCIS (Netherlands)

    Pal, F. van der; Balken, M.R. van; Heesakkers, J.P.; Debruyne, F.M.J.; Kiemeney, L.A.L.M.; Bemelmans, B.L.H.

    2006-01-01

    OBJECTIVE: To investigate the relationship between quality of life (QoL) and voiding variables in patients with lower urinary tract dysfunction treated with percutaneous tibial nerve stimulation (PTNS), as it is assumed that improvements in voiding will lead to a better QoL in such patients.

  17. Partial discharge patterns related to surface deterioration in voids in epoxy

    DEFF Research Database (Denmark)

    Holbøll, Joachim; Henriksen, Mogens

    1990-01-01

    Results are presented from an investigation of the relationship between changes in partial discharge patterns and the surface deterioration process taking place in small naturally formed spherical voids in epoxy plastic. The voids were exposed to a moderate electric stress above inception level...

  18. Parallel Void Thread in Long-Reach Ethernet Passive Optical Networks

    KAUST Repository

    Elrasad, Amr

    2015-06-25

    This work investigates void filling (idle periods) in long-reach Ethernet passive optical networks. We focus on reducing grant delays and hence reducing the average packet delay. We introduce a novel approach called parallel void thread (PVT), which allocates bandwidth grants during voids baseless of bandwidth requests. We introduce three different grant sizing schemes for PVT, namely void extension, count controlled batch void filling, and size controlled batch void filling. The proposed approaches canbe integrated with almost all of the previously reported dynamic bandwidth allocation schemes. Unlike other void filling schemes, PVT is less sensitive to the differential distance between optical network units and can work very well in the case of limited differential distances. We have analytically investigated the packet delay and derived a bound condition for PVT to outperform the other competitors. We support our work with extensive simulation study considering bursty traffic with long range dependence for both the single-class and differentiated services (DiffServ) scenarios. Numerical results show delay reduction up to 35% compared with the non-void filling scheme for the single-class scenario. For DiffServ traffic, PVT achieves delay reduction up to 80% for expedited forward traffic, 52% for assured forward traffic, and 56% for best effort traffic. © 2015 OSA.

  19. Linear redshift space distortions for cosmic voids based on galaxies in redshift space

    Science.gov (United States)

    Chuang, Chia-Hsun; Kitaura, Francisco-Shu; Liang, Yu; Font-Ribera, Andreu; Zhao, Cheng; McDonald, Patrick; Tao, Charling

    2017-03-01

    Cosmic voids found in galaxy surveys are defined based on the galaxy distribution in redshift space. We show that the large scale distribution of voids in redshift space traces the fluctuations in the dark matter density field δ(k) (in Fourier space with μ being the line of sight projected k-vector): δ_v^s(k) = (1 + β_v μ^2) b^s_v δ(k), with a beta factor that will be in general different than the one describing the distribution of galaxies. Only in case voids could be assumed to be quasi-local transformations of the linear (Gaussian) galaxy redshift space field, one gets equal beta factors β_v=β_g=f/b_g with f being the growth rate, and b_g, b^s_v being the galaxy and void bias on large scales defined in redshift space. Indeed, in our mock void catalogs we measure void beta factors being in good agreement with the galaxy one. Further work needs to be done to confirm the level of accuracy of the beta factor equality between voids and galaxies, but in general the void beta factor needs to be considered as a free parameter for RSD studies.

  20. A model for void-induced back reaction between radiolytic products in NaCl

    NARCIS (Netherlands)

    Turkin, A.A.; Dubinko, V.I.; Vainshtein, D.I.; Hartog, H.W. den

    A kinetic model is formulated for the chemical reaction between radiolytic sodium colloids and gas bubbles, which are brought into contact with each other during the exposure to ionising radiation by the growing voids. The reaction starts with the evaporation of Na atoms into the void due to the

  1. Size-effects at a crack-tip interacting with a number of voids

    DEFF Research Database (Denmark)

    Tvergaard, Viggo; Niordson, Christian Frithiof

    2008-01-01

    A strain gradient plasticity theory is used to analyse the growth of discretely represented voids in front of a blunting crack tip, in order to study the influence of size effects on two competing mechanisms of crack growth. For a very small void volume fraction the crack tip tends to interact...

  2. Non-spherical voids and lattice reorientation patterning in a shock-loaded Al single crystal

    DEFF Research Database (Denmark)

    Hong, Chuanshi; Fæster, Søren; Hansen, Niels

    2017-01-01

    An Al single crystal shock loaded in the direction and captured at incipient spallation was examined by combining X-ray tomography, electron backscatter diffraction on a scanning electron microscope, and transmission electron microscopy (TEM). Octahedral voids with {1 1 1} faces were...... of dislocation cells and extended dislocation boundaries, illustrating the importance of plastic deformation during void growth....

  3. Determination of gas pressure in voids in epoxy casting using an ultrasonic measuring technique

    DEFF Research Database (Denmark)

    Larsen, Esben; Petersen, C. Bak; Henriksen, Mogens

    1990-01-01

    the void. The results are based on the use of time delay spectrometry. This method gives a sufficiently high signal-to-noise ratio for detecting the transmitted part of the ultrasonic signal which has travelled through the void. Because of differences in the density and velocity of ultrasonic signals...

  4. 21 CFR 1305.19 - Cancellation and voiding of DEA Forms 222.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Cancellation and voiding of DEA Forms 222. 1305.19... I AND II CONTROLLED SUBSTANCES DEA Form 222 § 1305.19 Cancellation and voiding of DEA Forms 222. (a) A purchaser may cancel part or all of an order on a DEA Form 222 by notifying the supplier in...

  5. Spatial Distribution of Voids in Insulating Concrete Analyzed by Micro-CT Images and Probability Functions

    Directory of Open Access Journals (Sweden)

    Sang-Yeop Chung

    2015-01-01

    Full Text Available Insulating concrete is a multiphase material designed for reduced thermal conductivity, and the void distribution in concrete strongly affects its physical properties such as mechanical response and heat conduction. Therefore, it is essential to develop a method for identifying the spatial distribution of voids. To examine the voids of insulating concrete specimens, micro-CT (computed tomography images can be effectively used. The micro-CT images are binarized to visualize the void distribution and stacked to generate 3D specimen images. From the obtained images, the spatial distribution of the voids and the microscopic constituents inside the insulating concrete specimens can be identified. The void distribution in the material can be characterized using low-order probability functions such as two-point correlation, lineal-path, and two-point cluster functions. It is confirmed that micro-CT images and low-order probability functions are effective in describing the relative degree of void clustering and void connectivity in insulating concrete.

  6. Propagation of Love waves in an elastic layer with void pores

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    of longitudinal and shear waves in void media and came to the conclusion that there may be two wave fronts for longitudinal waves. Deyet al(1993) discussed the propagation of torsional surface waves in an elastic medium with void pores. The influence of local irregularities on propagation of Love waves has been studied ...

  7. Plane waves in a rotating generalized thermo-elastic solid with voids ...

    African Journals Online (AJOL)

    Propagation of plane waves in a rotating thermo-elastic solid with voids has been studied. The theory for thermo-elastic materials with voids developed by Iesan in the context of thermo- elastic theory of Lord and Shulman has been employed for mathematical treatment. It has been found that there exist one transverse wave ...

  8. Measurements of gas pressure in voids in epoxy castings for high voltage equipment

    DEFF Research Database (Denmark)

    Larsen, Esben; Henriksen, Mogens; Nielsen, E

    1988-01-01

    An investigation of samples of epoxy each containing one void, which were produced at different pressures, is reported. The samples were of the disk type with the void located in the center. The gas in the voids has a pressure somewhat related to the curing pressure, thereby directly influencing...... the partial-discharge inception voltage. Data show that gas pressure in voids in epoxy castings can be determined by use of an ultrasound test method. A relationship between the void gas pressure and the epoxy curing pressure is also found. This investigation is part of an effort to predict the inception...... voltage of partial discharges in high-voltage epoxy castings from the processing parameters...

  9. Blind void filling in LR-EPONs: How efficient it can be?

    KAUST Repository

    Elrasad, Amr

    2015-07-01

    This work proposes a novel blind void (idle periods) filling in Long-Reach Ethernet Passive Optical Networks (LR-EPONs) namely Size Controlled Batch Void Filling (SCBVF). We emphasize on reducing grant delays and hence reducing the average packet delay. SCBVF delay reduction is achieved by early flushing data during the idle time periods (voids) between allocated grants. The proposed approach can be integrated with almost all of the previously reported dynamic bandwidth allocation schemes. SCBVF is less sensitive to differential distance between ONUs and can work well in case of small differential distances compared to previously reported void filling schemes. We support our work by extensive simulation study considering bursty traffic with long range dependency. Numerical results show a delay reduction up to 35% compared to non-void filling scheme outperforming its main competitors that can achieve up to 7% delay reduction.

  10. Thermal analysis of void cavity for heat pipe receiver under microgravity

    Science.gov (United States)

    Gui, Xiaohong; Song, Xiange; Nie, Baisheng

    2017-04-01

    Based on theoretical analysis of PCM (Phase Change Material) solidification process, the model of improved void cavity distribution tending to high temperature region is established. Numerical results are compared with NASA (National Aeronautics and Space Administration) results. Analysis results show that the outer wall temperature, the melting ratio of PCM and the temperature gradient of PCM canister, have great difference in different void cavity distribution. The form of void distribution has a great effect on the process of phase change. Based on simulation results under the model of improved void cavity distribution, phase change heat transfer process in thermal storage container is analyzed. The main goal of the improved designing for PCM canister is to take measures in reducing the concentration distribution of void cavity by adding some foam metal into phase change material.

  11. Effect of void nucleation and growth on forming limit diagrams of textured aluminum alloy sheets

    Science.gov (United States)

    Hu, Jianguo; Jonas, John J.; Ishikawa, Takashi

    1998-08-01

    A numerical code has been developed to calculate Forming Limit Diagrams (FLDs) of textured aluminum alloy sheets. This code is based on the Marciniak-Kuczynski (M-K) model, but allows for void nucleation and growth so that limit strains and fracture strains can be predicted. The strain induced void nucleation model was employed together with the Cocks and Ashby's void growth model. The influences of initial texture, texture evolution, and void nucleation and growth during deformation on the FLDs of an Al-Mg alloy were all investigated. Satisfactory agreement was obtained between the predictions and measured data, It was also shown that the introduction of void damage into the old M-K model can lead to more reasonable and accurate predictions.

  12. Active infrared thermography for visualizing subsurface micro voids in an epoxy molding compound

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ji Yeol [Test and Package Center, Samsung Electronics, Asan(Korea, Republic of); Hwang, Soon Kyu; Choi, Jae Mook; Sohn, Hoon [Dept. of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2017-04-15

    This paper presents an automated subsurface micro void detection technique based on pulsed infrared thermography for inspecting epoxy molding compounds (EMC) used in electronic device packaging. Subsurface micro voids are first detected and visualized by extracting a lock-in amplitude image from raw thermal images. Binary imaging follows to achieve better visualization of subsurface micro voids. A median filter is then applied for removing sparse noise components. The performance of the proposed technique is tested using 36 EMC samples, which have subsurface (below 150 μm ~ 300 μm from the inspection surface) micro voids (150 μm ~ 300 μm in diameter). The experimental results show that the subsurface micro voids can be successfully detected without causing any damage to the EMC samples, making it suitable for automated online inspection.

  13. Behaviorism

    Science.gov (United States)

    Moore, J.

    2011-01-01

    Early forms of psychology assumed that mental life was the appropriate subject matter for psychology, and introspection was an appropriate method to engage that subject matter. In 1913, John B. Watson proposed an alternative: classical S-R behaviorism. According to Watson, behavior was a subject matter in its own right, to be studied by the…

  14. The lensing and temperature imprints of voids on the cosmic microwave background

    Science.gov (United States)

    Cai, Yan-Chuan; Neyrinck, Mark; Mao, Qingqing; Peacock, John A.; Szapudi, Istvan; Berlind, Andreas A.

    2017-04-01

    We have searched for the signature of cosmic voids in the cosmic microwave background (CMB), in both the Planck temperature and lensing-convergence maps; voids should give decrements in both. We use ZOBOV voids from the Data Release 12 Sloan Digital Sky Survey CMASS galaxy sample. We base our analysis on N-body simulations, to avoid a posteriori bias. For the first time, we detect the signature of voids in CMB lensing: the significance is 3.2σ, close to Λ cold dark matter (ΛCDM) in both amplitude and projected density-profile shape. A temperature dip is also seen, at modest significance (2.3σ), with an amplitude about six times the prediction. This temperature signal is induced mostly by voids with radii between 100 and 150 h-1 Mpc, while the lensing signal is mostly contributed by smaller voids - as expected; lensing relates directly to density, while integrated Sachs-Wolfe effect (ISW) depends on gravitational potential. The void abundance in observations and simulations agree as well. We also repeated the analysis excluding lower significance voids: no lensing signal is detected with an upper limit of about twice the ΛCDM prediction. But the mean temperature decrement now becomes non-zero at the 3.7σ level (similar to that found by Granett et al.), with an amplitude about 20 times the prediction. However, the observed dependence of temperature on void size is in poor agreement with simulations, whereas the lensing results are consistent with ΛCDM theory. Thus, the overall tension between theory and observations does not favour non-standard theories of gravity, despite the hints of an enhanced amplitude for the ISW effect from voids.

  15. The Santiago-Harvard-Edinburgh-Durham void comparison I: SHEDding light on chameleon gravity tests

    Science.gov (United States)

    Cautun, Marius; Paillas, Enrique; Cai, Yan-Chuan; Bose, Sownak; Armijo, Joaquin; Li, Baojiu; Padilla, Nelson

    2018-02-01

    We present a systematic comparison of several existing and new void finding algorithms, focusing on their potential power to test a particular class of modified gravity models - chameleon f(R) gravity. These models deviate from standard General Relativity (GR) more strongly in low-density regions and thus voids are a promising venue to test them. We use Halo Occupation Distribution (HOD) prescriptions to populate haloes with galaxies, and tune the HOD parameters such that the galaxy two-point correlation functions are the same in both f(R) and GR models. We identify both 3D voids as well as 2D underdensities in the plane-of-the-sky to find the same void abundance and void galaxy number density profiles across all models, which suggests that they do not contain much information beyond galaxy clustering. However, the underlying void dark matter density profiles are significantly different, with f(R) voids being more underdense than GR ones, which leads to f(R) voids having a larger tangential shear signal than their GR analogues. We investigate the potential of each void finder to test f(R) models with near-future lensing surveys such as EUCLID and LSST. The 2D voids have the largest power to probe f(R) gravity, with a LSST analysis of tunnel (which is a new type of 2D underdensity introduced here) lensing distinguishing at 80 and 11σ (statistical error) f(R) models with parameters, |fR0| = 10-5 and 10-6, from GR.

  16. Long-Term Effects of Two Formats of Cognitive Behavioral Therapy for Insomnia Comorbid with Breast Cancer.

    Science.gov (United States)

    Savard, Josée; Ivers, Hans; Savard, Marie-Hélène; Morin, Charles M

    2016-04-01

    The goal of this randomized controlled trial, conducted in breast cancer patients, was to assess the long-term efficacy of a video-based cognitive behavioral therapy for insomnia (VCBT-I), as compared to a professionally administered intervention (PCBT-I) and to a no-treatment group (CTL). An earlier report revealed that, at posttreatment, VCBT-I patients showed significantly greater sleep improvements than CTL, but that PCBT-I produced superior effects than VCBT-I on some sleep and secondary outcomes. In this report, long-term effects are compared. Two hundred forty-two women with breast cancer and with insomnia symptoms or using hypnotic medications participated to this three-arm randomized controlled trial: (1) PCBT-I (n = 81); (2) VCBT-I (n = 80); or (3) no treatment (CTL; n = 81) group. PCBT-I was composed of six weekly, individual sessions of approximately 50 min, whereas VCBT-I comprised a 60-min animated video and six booklets. Study measures (sleep and secondary variables) were administered at pretreatment and posttreatment, and at a 3-, 6-, and 12-mo follow-up. Treatment gains were well sustained at follow-up in both PCBT-I and VCBT-I. As at posttreatment, the remission rate of insomnia at follow-up was greater in PCBT-I than in VCBT-I, which was greater than in CTL. Although face-to-face therapy remains the optimal format to efficaciously administer CBT for insomnia in cancer patients, a minimal intervention, such as the video-based intervention tested in this study, produces significant and sustainable treatment effects. ClinicalTrials.gov identifier NCT00674830. © 2016 Associated Professional Sleep Societies, LLC.

  17. Yield and Failure Behavior Investigated for Cross-Linked Phenolic Resins Using Molecular Dynamics

    Science.gov (United States)

    Monk, Joshua D.; Lawson, John W.

    2016-01-01

    Molecular dynamics simulations were conducted to fundamentally evaluate the yield and failure behavior of cross-linked phenolic resins at temperatures below the glass transition. Yield stress was investigated at various temperatures, strain rates, and degrees of cross-linking. The onset of non-linear behavior in the cross-linked phenolic structures was caused by localized irreversible molecular rearrangements through the rotation of methylene linkers followed by the formation or annihilation of neighboring hydrogen bonds. The yield stress results, with respect to temperature and strain rate, could be fit by existing models used to describe yield behavior of amorphous glasses. The degree of cross-linking only indirectly influences the maximum yield stress through its influence on glass transition temperature (Tg), however there is a strong relationship between the degree of cross-linking and the failure mechanism. Low cross-linked samples were able to separate through void formation, whereas the highly cross-linked structures exhibited bond scission.

  18. Experimental Study on Voided Reinforced Concrete Beams with Polythene Balls

    Science.gov (United States)

    Sivaneshan, P.; Harishankar, S.

    2017-07-01

    The primary component in any structure is concrete, that exist in buildings and bridges. In present situation, a serious problems faced by construction industry is exhaustive use of raw materials. Recent times, various methods are being adopted to limit the use of concrete. In structural elements like beams, polythene balls can be induced to reduce the usage of concrete. A simply supported reinforced concrete beam has two zones, one above neutral axis and other below neutral axis. The region below neutral axis is in tension and above neutral axis is in compression. As concrete is weak in tension, steel reinforcements are provided in tension zone. The concrete below the neutral axis acts as a stress transfer medium between the compression zone and tension zone. The concrete above the neutral axis takes minimum stress so that we could partially replace the concrete above neutral axis by creating air voids using recycled polythene balls. Polythene balls of varying diameters of 75 mm, 65 mm and 35 mm were partially replaced in compression zone. Hence the usage of concrete in beams and self-weight of the beams got reduced considerably. The Load carrying capacity, Deflection of beams and crack patterns were studied and compared with conventional reinforced concrete beams.

  19. Void statistics of the CfA redshift survey

    Science.gov (United States)

    Vogeley, Michael S.; Geller, Margaret J.; Huchra, John P.

    1991-01-01

    Clustering properties of two samples from the CfA redshift survey, each containing about 2500 galaxies, are studied. A comparison of the velocity distributions via a K-S test reveals structure on scales comparable with the extent of the survey. The void probability function (VPF) is employed for these samples to examine the structure and to test for scaling relations in the galaxy distribution. The galaxy correlation function is calculated via moments of galaxy counts. The shape and amplitude of the correlation function roughly agree with previous determinations. The VPFs for distance-limited samples of the CfA survey do not match the scaling relation predicted by the hierarchical clustering models. On scales not greater than 10/h Mpc, the VPFs for these samples roughly follow the hierarchical pattern. A variant of the VPF which uses nearly all the data in magnitude-limited samples is introduced; it accounts for the variation of the sampling density with velocity in a magnitude-limited survey.

  20. Finger-like voids induced by viscous fingering during phase inversion of alumina/PES/NMP suspensions

    KAUST Repository

    Wang, Bo

    2012-07-01

    The formation mechanism of phase-inversion ceramic hollow fibre membranes has not been well understood. In this paper, we report on the formation of finger-like macrovoids during non-solvent-induced phase inversion of alumina/PES/NMP suspensions. A membrane structure without such finger-like macrovoids was observed when the suspension was slowly immersed into pure ethanol or a mixture of 70. wt% NMP and 30. wt% water, whereas finger-like macrovoids occurred when the suspension was slid into the non-solvents at higher speeds. We found that the formation process of finger-like macrovoids could be fully or partially reversed when nascent membranes were taken out from water shortly after immersion, depending on the duration of the immersion. Splitting of the fingers during the formation of the macrovoids was also observed during the phase inversion of two alumina/PES/NMP suspensions. These experimental observations were not predicted by current theories of finger-like macrovoid formation in polymer membranes, but appear to mimic the well-known viscous fingering phenomenon. We therefore propose that in the phase inversion of ceramic suspensions, the viscous fingering phenomenon is an important mechanism in the formation of finger-like voids. © 2012 Elsevier B.V.

  1. Seismic Response Reduction of Structures Equipped with a Voided Biaxial Slab-Based Tuned Rolling Mass Damper

    National Research Council Canada - National Science Library

    Li, Shujin; Fu, Liming; Kong, Fan

    2015-01-01

    .... The hollow slabs in this context, also referred to as "voided biaxial reinforced concrete slabs," feature a large interior space of prefabricated voided modules that are necessary in the construction...

  2. Nano-Particle Control of Void Formation and Expansion in Polymeric and Composite Systems

    National Research Council Canada - National Science Library

    Seferis, James C

    2006-01-01

    .... The most significant advancements and conclusions in this final report include interlayer modification of composites at the nanoscale and characterization of the interlayer behaviour of nanoparticle...

  3. Vacancy Migration and Void Formation during the Annealing of Electron Irradiated Molybdenum

    DEFF Research Database (Denmark)

    Evans, J. H.; Eldrup, Morten Mostgaard

    1975-01-01

    We have used a combination of three techniques—resistivity, positron annihilation and transmission electron microscopy (TEM)—to examine the recovery on annealing of point defect damage introduced into high purity molybdenum by 10 MeV electron irradiation. The work produced two points of particula...... interest, both arising directly from the sensitivity of the positron annihilation technique to vacancy defects....

  4. Cosmological exploitation of cosmic void statistics. New numerical tools in the CosmoBolognaLib to extract cosmological constraints from the void size function

    Science.gov (United States)

    Ronconi, Tommaso; Marulli, Federico

    2017-10-01

    Context. We present new numerical tools to analyse cosmic void catalogues, implemented inside the CosmoBolognaLib, a large set of open source C++/Python numerical libraries. Aims: The CosmoBolognaLib provides a common numerical environment for cosmological calculations. This work extends these libraries by adding new algorithms for cosmological analyses of cosmic voids, covering the existing gap between theory and observations. Methods: We implemented new methods to model the size function of cosmic voids, in both observed and simulated samples of dark matter and biased tracers. Moreover, we provide new numerical tools to construct unambiguous void catalogues. The latter are designed to be independent of the void finder, in order to allow a high versatility in comparing independent results. Results: The implemented open source software is available at the GitHub repository of the CosmoBolognaLib. We also provide a full doxygen documentation and some example codes that explain how to use these libraries. The implemented open source software is available at http://https://github.com/federicomarulli/CosmoBolognaLib

  5. Study of galaxies in the Lynx-Cancer void - I. Sample description

    Science.gov (United States)

    Pustilnik, S. A.; Tepliakova, A. L.

    2011-08-01

    The evolution of galaxies is influenced by the environment in which they reside. This effect should be strongest for the lowest-mass and -luminosity galaxies. To study dwarf galaxies in extremely low density environments, we have compiled a deep catalogue of dwarf galaxies in the nearby Lynx-Cancer void. This void hosts some of the most metal-poor dwarfs known to date. It borders the Local Volume at negative supergalactic Z(SGZ) coordinates and has a size of more than 16 Mpc. With a distance to its centre of only 18 Mpc, it is close enough to allow a search for the faintest dwarfs. Within the void 75 dwarf (-11.9 > MB > -18.0) and four subluminous (-18.0 > MB > -18.4) galaxies have been identified. We present the parameters of the void galaxies and a detailed analysis of the completeness of the catalogue as a function of magnitude and surface brightness. The catalogue appears almost complete to MB < -14 mag, but misses part of the fainter low surface brightness (LSB) face-on galaxies. This sample of void galaxies builds the basis of forthcoming observational studies that will provide insight into the main stellar population, H I mass-to-light ratio, metallicity and age for comparison with dwarfs in higher density regions. We briefly summarize the information on the unusual objects in the void and conclude that their concentration hints that voids are environments that are favourable for finding and studying unevolved dwarf galaxies.

  6. DIVE in the cosmic web: voids with Delaunay triangulation from discrete matter tracer distributions

    Science.gov (United States)

    Zhao, Cheng; Tao, Charling; Liang, Yu; Kitaura, Francisco-Shu; Chuang, Chia-Hsun

    2016-07-01

    We present a novel parameter-free cosmological void finder (DIVE, Delaunay TrIangulation Void findEr) based on Delaunay Triangulation (DT), which efficiently computes the empty spheres constrained by a discrete set of tracers. We define the spheres as DT voids, and describe their properties, including a universal density profile together with an intrinsic scatter. We apply this technique on 100 halo catalogues with volumes of 2.5 h-1Gpc side each, with a bias and number density similar to the Baryon Oscillation Spectroscopic Survey CMASS luminous red galaxies, performed with the PATCHY code. Our results show that there are two main species of DT voids, which can be characterized by the radius: they have different responses to halo redshift space distortions, to number density of tracers, and reside in different dark matter environments. Based on dynamical arguments using the tidal field tensor, we demonstrate that large DT voids are hosted in expanding regions, whereas the haloes used to construct them reside in collapsing ones. Our approach is therefore able to efficiently determine the troughs of the density field from galaxy surveys, and can be used to study their clustering. We further study the power spectra of DT voids, and find that the bias of the two populations are different, demonstrating that the small DT voids are essentially tracers of groups of haloes.

  7. Interfacial area, velocity and void fraction in two-phase slug flow

    Energy Technology Data Exchange (ETDEWEB)

    Kojasoy, G. [Univ. of Wisconsin, Milwaukee, WI (United States); Riznic, J.R. [Atomic Energy Control Board, Ottawa (Canada)

    1997-12-31

    The internal flow structure of air-water plug/slug flow in a 50.3 mm dia transparent pipeline has been experimentally investigated by using a four-sensor resistivity probe. Liquid and gas volumetric superficial velocities ranged from 0.55 to 2.20 m/s and 0.27 to 2.20 m/s, respectively, and area-averaged void fractions ranged from about 10 to 70%. The local distributions of void fractions, interfacial area concentration and interface velocity were measured. Contributions from small spherical bubbles and large elongated slug bubbles toward the total void fraction and interfacial area concentration were differentiated. It was observed that the small bubble void contribution to the overall void fraction was small indicating that the large slug bubble void fraction was a dominant factor in determining the total void fraction. However, the small bubble interfacial area contribution was significant in the lower and upper portions of the pipe cross sections.

  8. Stress Voiding in IC Interconnects - Rules of Evidence for Failure Analysts

    Energy Technology Data Exchange (ETDEWEB)

    FILTER, WILLIAM F.

    1999-09-17

    Mention the words ''stress voiding'', and everyone from technology engineer to manager to customer is likely to cringe. This IC failure mechanism elicits fear because it is insidious, capricious, and difficult to identify and arrest. There are reasons to believe that a damascene-copper future might be void-free. Nevertheless, engineers who continue to produce ICs with Al-alloy interconnects, or who assess the reliability of legacy ICs with long service life, need up-to-date insights and techniques to deal with stress voiding problems. Stress voiding need not be fearful. Not always predictable, neither is it inevitable. On the contrary, stress voids are caused by specific, avoidable processing errors. Analytical work, though often painful, can identify these errors when stress voiding occurs, and vigilance in monitoring the improved process can keep it from recurring. In this article, they show that a methodical, forensics approach to failure analysis can solve suspected cases of stress voiding. This approach uses new techniques, and patiently applies familiar ones, to develop evidence meeting strict standards of proof.

  9. submitter Thermal stability of interface voids in Cu grain boundaries with molecular dynamic simulations

    CERN Document Server

    Xydou, A; Aicheler, M; Djurabekova, F

    2016-01-01

    By means of molecular dynamic simulations, the stability of cylindrical voids is examined with respect to the diffusion bonding procedure. To do this, the effect of grain boundaries between the grains of different crystallographic orientations on the void closing time was studied at high temperatures from 0.7 up to 0.94 of the bulk melting temperature $(T_m)$. The diameter of the voids varied from 3.5 to 6.5 nm. A thermal instability occurring at high temperatures at the surface of the void placed in a grain boundary triggered the eventual closure of the void at all examined temperatures. The closing time has an exponential dependence on the examined temperature values. A model based on the defect diffusion theory is developed to predict the closing time for voids of macroscopic size. The diffusion coefficient within the grain boundaries is found to be overall higher than the diffusion coefficient in the region around the void surface. The activation energy for the diffusion in the grain boundary is calculate...

  10. Efficacy of a cartoon and photograph montage storybook in preparing children for voiding cystourethrogram.

    Science.gov (United States)

    Gebarski, Kathleen S; Daley, Jamie; Gebarski, Matthew W; Keshavarzi, Nahid; Hernandez, Ramiro J; Ivanzic, Vesna; Gebarski, Stephen S

    2013-11-01

    Undergoing voiding cystourethrogram (VCUG) can be distressing for children. To assess the efficacy of a cartoon and photograph montage storybook in preparing children for VCUG. Outpatient children (ages 2-14 years) who had VCUGs between December 2011 and June 2012 were randomly assigned to two groups; one group received the storybook a week before the procedure. Parents and guardians were asked to complete an anonymous survey rating their child's tolerance of the exam from 1 to 5, worst to best, immediately after VCUG. The VCUG technologist also rated the child's tolerance. Children prepared for VCUG with the storybook had less distress than those without. Results were analyzed by Cochran-Mantel-Haenszel and Cochran-Armitage Trend exact tests, a P value of both tests of 0.0092 indicating a statistically significant difference between the tolerance scores of children prepared with the storybook and those without. Effects of gender and history of VCUG were not statistically significant. Two-thirds of all children had no other source of information. The cartoon and photograph montage storybook format of preparing children for VCUG was effective in increasing their tolerance for the procedure. The storybook should be mailed out in advance because the majority of families did not pursue information on preparing their children for VCUG.

  11. A variational constitutive model for the distribution and interactions of multi-sized voids

    KAUST Repository

    Liu, Jinxing

    2013-07-29

    The evolution of defects or voids, generally recognized as the basic failure mechanism in most metals and alloys, has been intensively studied. Most investigations have been limited to spatially periodic cases with non-random distributions of the radii of the voids. In this study, we use a new form of the incompressibility of the matrix to propose the formula for the volumetric plastic energy of a void inside a porous medium. As a consequence, we are able to account for the weakening effect of the surrounding voids and to propose a general model for the distribution and interactions of multi-sized voids. We found that the single parameter in classical Gurson-type models, namely void volume fraction is not sufficient for the model. The relative growth rates of voids of different sizes, which can in principle be obtained through physical or numerical experiments, are required. To demonstrate the feasibility of the model, we analyze two cases. The first case represents exactly the same assumption hidden in the classical Gurson\\'s model, while the second embodies the competitive mechanism due to void size differences despite in a much simpler manner than the general case. Coalescence is implemented by allowing an accelerated void growth after an empirical critical porosity in a way that is the same as the Gurson-Tvergaard-Needleman model. The constitutive model presented here is validated through good agreements with experimental data. Its capacity for reproducing realistic failure patterns is shown by simulating a tensile test on a notched round bar. © 2013 The Author(s).

  12. Closing the gap between behavior and models in route choice: The role of spatiotemporal constraints and latent traits in choice set formation

    DEFF Research Database (Denmark)

    Kaplan, Sigal; Prato, Carlo Giacomo

    2012-01-01

    A considerable gap exists between the behavioral paradigm of choice set formation in route choice and its representation in route choice modeling. While travelers form their viable choice set by retaining routes that satisfy spatiotemporal constraints, existing route generation techniques do not ...... spatiotemporal constraints and latent traits in route choice models, and (iii) the linkage between spatiotemporal constraints and time saving, spatial and mnemonic abilities....

  13. Effect of nonuniform 3-D void distribution within BWR fuel assemblies on neutronic characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Toshikazu; Hyoudou, Hideaki; Kitada, Takanori [Osaka Univ., Suita (Japan). Dept. of Nuclear Engineering]. E-mail: takeda@nucl.eng.osaka-u.ac.jp; Kosaka, Shinya; Ikeda, Hideaki [Tepco Systems Corp., Tokyo (Japan)]. E-mail: kisaka-shinya@tepsys.co.jp

    2003-07-01

    The effect of nonuniform distribution of void fractions within fuel assemblies of BWR cores on the neutronic characteristics has been evaluated by coupling the thermal hydraulic and neutronic calculations. It is found that the effect is large for assemblies with Gd rods because of the small void fraction for subchannels with Gd rods. The axially averaged K{sub {infinity}} is reduced by about 0.1 {approx} 0.3% {delta}k/k compared with the case with uniform void distribution. The power peaking is decreased by 0.6 {approx} 1.3%. The reason of these changes is discussed. (author)

  14. Effects of percutaneous posterior tibial nerve stimulation on voiding dysfunctions in cerebral palsy: A case report

    Directory of Open Access Journals (Sweden)

    Farshideh Alishahi

    2017-01-01

    Full Text Available The present study, conducted on three children with cerebral palsy who had voiding dysfunction. After collecting demographic information, symptoms of voiding dysfunctions were recorded. Then; we did an ultrasonographic evaluation of the bladder to measure residual urine volume. Physiotherapy treatment through percutaneous electrical stimulation of the posterior tibial nerve was performed in 12 sessions. Bladder ultrasonography was repeated after treatment. Abnormal residual urine volume became normal in patients with urinary retention. Percutaneous posterior tibial nerve stimulation reduces symptoms of voiding dysfunctions in children with cerebral palsy

  15. Studies of void growth in a thin ductile layer between ceramics

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    1997-01-01

    The growth of voids in a thin ductile layer between ceramics is analysed numerically, using an axisymmetric cell model to represent an array of uniformly distributed spherical voids at the central plane of the layer. The purpose is to determine the full traction-separation law relevant to crack...... growth by a ductile mechanism along the thin layer. Plastic flow in the layer is highly constrained by the ceramics, so that a high. level of triaxial tension develops, leading in some cases to cavitation instabilities. The computations are continued to a state near the occurrence of void coalescence....

  16. Comparative sodium void effects for different advanced liquid metal reactor fuel and core designs

    Energy Technology Data Exchange (ETDEWEB)

    Dobbin, K.D.; Kessler, S.F.; Nelson, J.V.; Gedeon, S.R.; Omberg, R.P.

    1991-07-01

    An analysis of metal-, oxide, and nitride-fueled advanced liquid metal reactor cores was performed to investigate the calculated differences in sodium void reactivity, and to determine the relationship between sodium void reactivity and burnup reactivity swing using the three fuel types. The results of this analysis indicate that nitride fuel has the least positive sodium void reactivity for any given burnup reactivity swing. Thus, it appears that a good design compromise between transient overpower and loss of flow response is obtained using nitride fuel. Additional studies were made to understand these and other nitride advantages. 8 refs., 5 figs., 3 tabs.

  17. Effect of Void Size on the Detonation Pressure of Emulsion Explosives

    Science.gov (United States)

    Hirosaki, Yoshikazu; Murata, Kenji; Kato, Yukio; Itoh, Shigeru

    2002-07-01

    To study the effect of void size, detonation pressure as well as detonation velocity was measured using PVDF pressure gauge for the emulsion explosives sensitized with plastic balloons of five different size ranging from 0.05mm to 2.42mm. The experimental results were compared with the detonation pressure and velocity calculated using KHT code. The experimental results showed that the detonation pressure and velocity were strongly affected by void size, and that the fraction of ammonium nitrate reacted in the reaction zone was strongly dependent on void size.

  18. The role of bone void fillers in medial opening wedge high tibial osteotomy: a systematic review.

    Science.gov (United States)

    Slevin, Omer; Ayeni, Olufemi R; Hinterwimmer, Stefan; Tischer, Thomas; Feucht, Matthias J; Hirschmann, Michael T

    2016-11-01

    A variety of bone void filling materials and methods are available in opening medial wedge HTO (OWHTO). The pertinent question revolves around if and when bone void fillers are needed. The primary purpose of this study was to systematically review outcomes and complications after OWHTO with and without the use of bone void fillers. The EMBASE, PubMed\\MEDLINE, Cochrane Library and Google Scholar databases were searched to identify articles that reported OWHTO results using different bone void fillers until March 2016. Only articles reporting the exact bone void filler type, the opening gap size and the fixation method were included. The extracted data included the study design, demographic data, the radiological and clinical results and complication rates. Outcomes were analysed with regard to bone void filler type, and comparison was made between the groups (allograft, autograft, synthetic bone void filler and OWHTO without bone void filling). Twenty-two articles reporting the results of 1421 OWHTO met the inclusion criteria. In total, 647 osteotomies were completed with allogeneic graft as bone void filler, 367 with synthetic materials, 199 with autograft and 208 without any bone void filling material. The maximum opening gap size was similar in all groups with mean of 9.8 mm (range 4-17.5 mm). Locking plate fixation was used in 90 % of the osteotomies that were completed without bone void filler, while all allograft cases and more then 90 % of the autograft cases were done with non-locking systems. The highest rates of non-union (1.1 %) were seen in the synthetic group, compared to 0.5 % in the all the other groups. This systematic review showed no definitive advantages for OWHTO with any bone void filler in terms of union rates and loss of correction. Moreover, the use of autografts or allografts showed more favourable outcomes than synthetic bone substitutes. OWHTO with gaps smaller then 10 mm and rigid fixation might be successfully managed without

  19. Cyclic voiding cystouretrography without the use of fluoroscopic monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Kadioglu, Alev [ALKA Medical Imaging Center, Buyukdere Cad. Levent Apt. No: 36/16, 80200-Mecidiyekoy, Istanbul (Turkey)]. E-mail: alevkadioglu@yahoo.com; Mihmanli, Ismail [Istanbul University, Cerrahpasa Medical Faculty, Department of Radiology, 34300-Istanbul (Turkey); Kantarci, Fatih [Istanbul University, Cerrahpasa Medical Faculty, Department of Radiology, 34300-Istanbul (Turkey); Tekes, Aylin [ALKA Medical Imaging Center, Buyukdere Cad. Levent Apt. No: 36/16, 80200-Mecidiyekoy, Istanbul (Turkey); Uysal, Omer [Istanbul University, Cerrahpasa Medical Faculty, Department of Biostatistics, 34300-Istanbul (Turkey)

    2006-01-15

    Purpose: To determine whether cyclic voiding cystourethrography (VCUG) examinations can be performed without using real-time fluoroscopic monitoring. Materials and methods: VCUG examinations were performed in 209 children (133 girls and 76 boys). In each child, it was performed in a cyclic manner (three consecutive cycles) without using fluoroscopic monitoring and one radiograph was taken in each cycle of the examination. All patients were sedated by midazolam prior to examination. The degree of vesicoureteric reflux (VUR) was graded for each of the kidney ureter units (KUU) (total 418 KUU) separately. Statistical analysis included the comparison of the presence and absence of VUR and three ordinal-matched comparisons of each cycle. Results: VCUG was detected in 37.3% of the children (78/209) and 28.7% (120/418) of the KUU. The absence of or same degree of VUR in three consecutive cycles were obtained in 345 KUU and the agreement was calculated as 82.5%. The same degree and presence of reflux were found in 85 and 89 refluxing KUU, the same negative findings (absence of VUR) in 306 and 298 KUU, and discordant findings in 27 and 31 KUU (between the first and second and between first and third cycles), respectively. Therefore, the agreement was 93.5 and 92.5% between the first and second cycles (p = 0.70) and between the first and the third cycles (p = 0.15), respectively. Conclusion: Both the cyclic nature of this study and the results indicated that VCUG without real-time fluoroscopic monitoring could be used where adequate fluoroscopic examination is not possible for children in whom VUR detection is necessary and impacts treatment. However, the responsibility of pediatric radiologist always must also include the task to provide proper equipment for imaging children with suspected VUR.

  20. Effect of the martensite distribution on the strain hardening and ductile fracture behaviors in dual-phase steel

    Energy Technology Data Exchange (ETDEWEB)

    Park, Kyosun, E-mail: paku08@zaiko.kyushu-u.ac.jp [Graduate School of Engineering, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395 (Japan); Nishiyama, Masato, E-mail: nishiyama11@zaiko.kyushu-u.ac.jp [Graduate School of Engineering, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395 (Japan); Nakada, Nobuo, E-mail: nakada@zaiko.kyushu-u.ac.jp [Department of Materials Science and Engineering, Graduate School of Engineering, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395 (Japan); International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395 (Japan); Tsuchiyama, Toshihiro, E-mail: toshi@zaiko.kyushu-u.ac.jp [Department of Materials Science and Engineering, Graduate School of Engineering, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395 (Japan); International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395 (Japan); Takaki, Setsuo, E-mail: takaki@zaiko.kyushu-u.ac.jp [Department of Materials Science and Engineering, Graduate School of Engineering, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395 (Japan); International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395 (Japan)

    2014-05-01

    In order to clarify the effects of the martensite distribution on the mechanical properties of low-carbon dual-phase steel, four types of dual-phase steel with different ferrite grain sizes and martensite distributions were prepared using a thermomechanical treatment. The tensile properties of these steels were investigated; in particular, the strain hardening and the ductile fracture behaviors were discussed in terms of the strain partitioning between the ferrite and martensite and the formation and growth of micro-voids, respectively. When the martensite grains surround the ferrite grains and form a chain-like networked structure, the strain hardenability is greatly improved without a significant loss of elongation, while the necking deformability is considerably reduced. A digital-image correlation analysis revealed that the tensile strain in the martensite region in the chain-like networked dual-phase structure is markedly increased during tensile deformation, which leads to an improvement in the strain hardenability. On the other hand, the joint part of the martensite grains in the structure acts as a preferential formation site for micro-voids. The number density of the micro-voids rapidly increases with increasing tensile strain, which would cause the lower necking deformability.

  1. Dielectric particle and void resonators for thin film solar cell textures.

    Science.gov (United States)

    Mann, Sander A; Grote, Richard R; Osgood, Richard M; Schuller, Jon A

    2011-12-05

    Using Mie theory and Rigorous Coupled Wave Analysis (RCWA) we compare the properties of dielectric particle and void resonators. We show that void resonators-low refractive index inclusions within a high index embedding medium-exhibit larger bandwidth resonances, reduced peak scattering intensity, different polarization anisotropies, and enhanced forward scattering when compared to their particle (high index inclusions in a low index medium) counterparts. We evaluate amorphous silicon solar cell textures comprising either arrays of voids or particles. Both designs support substantial absorption enhancements (up to 45%) relative to a flat cell with anti-reflection coating, over a large range of cell thicknesses. By leveraging void-based textures 90% of above-bandgap photons are absorbed in cells with maximal vertical dimension of 100 nm.

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

    DEFF Research Database (Denmark)

    Singh, B.N.; Eldrup, Morten Mostgaard; Zinkle, S.J.

    2001-01-01

    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 wasdemonstrated that the grain size dependent...... 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 significantdifference, the effect of grain size on void swelling under cascade damage conditions has been investigated both experimentally and theoretically...... was calculated within the framework of the production biasmodel (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...

  3. Forensic investigation of two voided slab bridges in the Virginia Department of Transportation's Richmond District.

    Science.gov (United States)

    2017-06-01

    The precast prestressed concrete voided slab structure is a popular bridge design because of its rapid construction and cost : savings in terms of eliminating formwork at the jobsite. However, the longitudinal shear transfer mechanism often fails, le...

  4. Constitutive modeling of void-growth-based tensile ductile failures with stress triaxiality effects

    KAUST Repository

    Mora Cordova, Angel

    2014-07-01

    In most metals and alloys, the evolution of voids has been generally recognized as the basic failure mechanism. Furthermore, stress triaxiality has been found to influence void growth dramatically. Besides strain intensity, it is understood to be the most important factor that controls the initiation of ductile fracture. We include sensitivity of stress triaxiality in a variational porous plasticity model, which was originally derived from hydrostatic expansion. Under loading conditions rather than hydrostatic deformation, we allow the critical pressure for voids to be exceeded so that the growth due to plasticity becomes dependent on the stress triaxiality. The limitations of the spherical void growth assumption are investigated. Our improved constitutive model is validated through good agreements with experimental data. Its capacity for reproducing realistic failure patterns is also indicated by a numerical simulation of a compact tensile (CT) test. © 2013 Elsevier Inc.

  5. Comparison of spacing factors as measured by the air-void analyzer and ASTM C457.

    Science.gov (United States)

    2015-12-01

    The Kansas Department of Transportation (KDOT) began using the Air-Void Analyzer (AVA) in : 2001 and first incorporated an AVA spacing factor requirement into paving specifications beginning in late : 2002. In 2005, a statewide investigation to evalu...

  6. Evaluation of Voids on Shrink PVC Film by Varying Gravure Process Variables

    Directory of Open Access Journals (Sweden)

    Akshay Vijay Joshi

    2013-01-01

    Full Text Available Gravure is one of the widely used processes for printing on shrink films, the reason being its consistency for longer runs. However, printing these shrink films comes with new challenges. The presence of gels, black specks and other contaminations in these films do not allow the surrounding area to print resulting in print void. The occurrence of this defect in a considerable amount or size on the area of interest leads to the rejection of printed stock that involves wastage of inks, solvents and time. The research involves the investigation of the effect of gravure process variables on minimization of print voids in Shrink PVC film. The gravure process variables viz. viscosity, pressure, speed and hardness were identified for laser engraved cylinder. It was found that Hardness had a significant impact on minimizing the voids while Viscosity-Hardness interaction was important. The results showed reduction in void area with lower viscosity, higher pressure, lower speed and higher hardness.

  7. The effect of form pressure on the air void structure of SCC

    DEFF Research Database (Denmark)

    Jensen, Mikkel Vibæk; Hasholt, Marianne Tange; Geiker, Mette Rica

    2005-01-01

    on the air void structure of hardened, air entrained SCC. The subject was examined through laboratory investigations of SCC with two different amounts of air entrainment. The condition in the form was simulated by using containers making it possible to cure concrete under various pressures corresponding......The high workability of self-compacting concrete (SCC) invites to high casting rates. However, casting walls at high rate may result in large pressure at the bottom of the form and subsequently compression of the air voids. This paper deals with the influence of hydrostatic pressure during setting...... to the bottom of castings of 0, 2, 4, and 6 meters height. The laboratory investigations were supplemented with data from two full-scale wall castings. The air void structure of the hardened concretes was determined on plane sections. The results indicate that the pressure related changes of the air void...

  8. Three-Dimensional Computed Tomography as a Method for Finding Die Attach Voids in Diodes

    Science.gov (United States)

    Brahm, E. N.; Rolin, T. D.

    2010-01-01

    NASA analyzes electrical, electronic, and electromechanical (EEE) parts used in space vehicles to understand failure modes of these components. The diode is an EEE part critical to NASA missions that can fail due to excessive voiding in the die attach. Metallography, one established method for studying the die attach, is a time-intensive, destructive, and equivocal process whereby mechanical grinding of the diodes is performed to reveal voiding in the die attach. Problems such as die attach pull-out tend to complicate results and can lead to erroneous conclusions. The objective of this study is to determine if three-dimensional computed tomography (3DCT), a nondestructive technique, is a viable alternative to metallography for detecting die attach voiding. The die attach voiding in two- dimensional planes created from 3DCT scans was compared to several physical cross sections of the same diode to determine if the 3DCT scan accurately recreates die attach volumetric variability

  9. Effects of percutaneous posterior tibial nerve stimulation on voiding dysfunctions in cerebral palsy: A case report

    OpenAIRE

    Farshideh Alishahi; Reza Farjad; Farideh Dehghan Manshadi

    2016-01-01

    The present study, conducted on three children with cerebral palsy who had voiding dysfunction. After collecting demographic information, symptoms of voiding dysfunctions were recorded. Then; we did an ultrasonographic evaluation of the bladder to measure residual urine volume. Physiotherapy treatment through percutaneous electrical stimulation of the posterior tibial nerve was performed in 12 sessions. Bladder ultrasonography was repeated after treatment. Abnormal residual urine volume becam...

  10. X-ray Computed Tomography Assessment of Air Void Distribution in Concrete

    Science.gov (United States)

    Lu, Haizhu

    Air void size and spatial distribution have long been regarded as critical parameters in the frost resistance of concrete. In cement-based materials, entrained air void systems play an important role in performance as related to durability, permeability, and heat transfer. Many efforts have been made to measure air void parameters in a more efficient and reliable manner in the past several decades. Standardized measurement techniques based on optical microscopy and stereology on flat cut and polished surfaces are widely used in research as well as in quality assurance and quality control applications. Other more automated methods using image processing have also been utilized, but still starting from flat cut and polished surfaces. The emergence of X-ray computed tomography (CT) techniques provides the capability of capturing the inner microstructure of materials at the micrometer and nanometer scale. X-ray CT's less demanding sample preparation and capability to measure 3D distributions of air voids directly provide ample prospects for its wider use in air void characterization in cement-based materials. However, due to the huge number of air voids that can exist within a limited volume, errors can easily arise in the absence of a formalized data processing procedure. In this study, air void parameters in selected types of cement-based materials (lightweight concrete, structural concrete elements, pavements, and laboratory mortars) have been measured using micro X-ray CT. The focus of this study is to propose a unified procedure for processing the data and to provide solutions to deal with common problems that arise when measuring air void parameters: primarily the reliable segmentation of objects of interest, uncertainty estimation of measured parameters, and the comparison of competing segmentation parameters.

  11. Investigation on Void Effect on Shear Stress Field in Bonded Stepped-Lap Joint

    OpenAIRE

    Ghoddous,Behnam; Shishehsaz,Mohamad

    2016-01-01

    Abstract In this paper, an adhesively-bonded stepped-lap joint suffering from a void within its adhesive layer is investigated. The void separates the layer into two sections. The joint is under tensile load and materials are isotropic and assumed to behave as linear elastic. Classical elasticity theory is used to determine shear stress distribution in the separated sections of adhesive layer along the overlap length. A set of differential equations was derived and solved by using appropriate...

  12. An improved void-resistance model for abandoned coal mine gas reservoirs

    OpenAIRE

    Shi, JQ; Rubio, RM; Durucan, S.

    2016-01-01

    Previous studies have shown that the gas pressure behaviour of some abandoned coal mines may be described with the aid of a simple conceptual model, the so called void-resistance model. In this study, an improved void-resistance model has been developed and validated using previously collected data. Two model parameters, i.e. an apparent source/sink pressure and a time constant, which control the gas pressure behaviour during recharge and under certain gas production conditions, are defined. ...

  13. Experimental Studies on Void Detection in Concrete-filled Steel Tubes using Ultrasound

    OpenAIRE

    Dong, W; Wu, Z; Zhou, X; Tan, Y

    2016-01-01

    Due to shrinkage and/or inadequate compaction during concreting, voids may develop in a concrete-filled steel tube (CFST) between the concrete core and outer steel tube, which reduce the confinement effect of the steel tube on the concrete core, and further, decrease the load-carrying capacity and ductility of a CFST. In this study, an ultrasonic technique is utilized for quantifying voids in CFSTs by analyzing the ultrasound travel time in them. Four potential travel paths are identified in ...

  14. An epidemiologic study of voiding and bowel habits in Korean children: a nationwide multicenter study.

    Science.gov (United States)

    Chung, Jae Min; Lee, Sang Don; Kang, Dong Ii; Kwon, Dong Deuk; Kim, Kun Suk; Kim, Su Yung; Kim, Han Gwun; Moon, Du Geon; Park, Kwan Hyun; Park, Yong Hyun; Pai, Ki Soo; Suh, Hong Jin; Lee, Jung Won; Cho, Won Yeol; Ha, Tae Sun; Han, Sang Won

    2010-07-01

    To evaluate the prevalence of abnormal voiding and bowel habits in healthy children, and to identify possible relationships between personal and familial factors and voiding and/or bowel habits. A randomly selected cross-sectional study was conducted in 19,240 children (5-13 years old) nationwide in the Republic of Korea. Parents were asked to complete questionnaires, which included items about nocturnal enuresis, daytime dysfunctional voiding symptoms (DVSs), and abnormal bowel habits (ABHs). Rates and associated factors were investigated. The overall rates of DVS, ABH, and of both were 46.4%, 31.3%, and 18.4%, respectively, and nocturnal enuresis was reported in 919 (5.6%). Daytime dysfunctional voiding symptoms were as follows: increased voiding frequency in 419 (2.5%), decreased voiding frequency in 720 (4.4%), urgency in 2740 (16.6%), daytime incontinence in 1854 (11.2%), urge incontinence in 2775 (16.8%), and holding maneuvers or postponed voiding in 3888 (23.5%). ABHs were as follows: constipation by frequency in 1103 (6.7%), constipation by the Bristol scale in 1941 (11.8%), fecal incontinence in 1293 (7.8%), and difficult or painful defecation in 2609 (15.8%). Delayed stool control, history of urinary tract infection, and a double-income family were positively associated with DVS or ABH or both. Furthermore, fathers with a low level of education and a low income were found to be associated with higher risk of ABH or DVS or both. Delayed stool control, a history of urinary tract infection, a low paternal level of education, a double-income family, and a lower family income had a negative effect on voiding or bowel habits in children. Copyright 2010 Elsevier Inc. All rights reserved.

  15. Evaluation of School Children%u2019s Voiding Problems in Sakarya Region

    Directory of Open Access Journals (Sweden)

    Adil Sonbahar

    2014-03-01

    Full Text Available Aim: Our goal was to determine the types of voiding problems of children%u2019s between 6 and 15 years old in Sakarya region. Material and Method: Totally 3246, 5-16 years old student randomly selected from 8 schools inside province. Students are evaluated in an appropriate room at school with a form pre-prepared in our clinic. Results: The survey shows that 486 of 3246 students (15% have voiding problems. The prevalance of dysfunctional voiding problems in all children, was 11.2%(365, nocturia prevalence was 8.7% (279, diurnal enuresis was 1% (32. In boys (totally 1573 the prevalance of dysfunctional voiding problems was 9% (145, nocturia prevalence was 11.7%(184, enuresis nocturia prevalence 11.2% (176, diurnal enuresis was 0.5% (8. In girls (totally 1673 the prevalance of dysfunctional voiding problems was 13.4 (223, nocturia prevalence was 6.7% (111, enuresis nocturia prevalence was 6.2% (103, diurnal enuresis prevalance was 1.4% (24. There was no meaningful statistical difference from the perspective of height and body mass index (BMI between the children with voiding problems and without any problem (p>0.05 . Discussion: The results for enuresis nocturna, nocturia and diurnal enuresis we have got from our study, are similar to ones that have been done in our country before. There is no data for prevalence od dysfunctional voiding study so far. Dysfunctional voiding problems in girls and in children who are in first years of school are more frequent.

  16. Quantitative void fraction detection with an eddy current flowmeter for generation IV Sodium cooled Fast Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, M. [Institut de Mecanique des Fluides de Toulouse, 2 Allee du Professeur Camille Soula, 31400 Toulouse, (France); French Atomic Energy and Alternative Energies Commission (CEA), DEN, Laboratory of Instrumentation and technological Test, Cadarache, 13108 Saint Paul lez Durance, (France); Tordjeman, Ph.; Bergez, W. [Institut de Mecanique des Fluides de Toulouse, 2 Allee du Professeur Camille Soula, 31400 Toulouse, (France); Cavaro, M.; Paumel, K.; Jeannot, J. P. [French Atomic Energy and Alternative Energies Commission (CEA), DEN, Laboratory of Instrumentation and technological Test, Cadarache, 13108 Saint Paul lez Durance, (France)

    2015-07-01

    This study was carried out to understand the response of an eddy current type flowmeter in two phase liquid-metal flow. We use the technique of ellipse fit and correlate the fluctuations in the angle of inclination of this ellipse with the void fraction. The effects of physical parameters such as coil excitation frequency and flow velocity have been studied. The results show the possibility of using an eddy current flowmeter as a gas detector for large void fractions. (authors)

  17. Quantitative void fraction measurement with an eddy current flowmeter for generation IV Sodium cooled Fast Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, M. [Institut de Mecanique des Fluides de Toulouse, 2 Allee du Professeur Camille Soula, 31400 Toulouse (France); CEA, DEN, Nuclear Technology Department, F-13108 Saint-Paul-lez-Durance (France); Tordjeman, Ph.; Bergez, W. [Institut de Mecanique des Fluides de Toulouse, 2 Allee du Professeur Camille Soula, 31400 Toulouse (France); Cavaro, M.; Paumel, K.; Jeannot, J.P. [CEA, DEN, Nuclear Technology Department, F-13108 Saint-Paul-lez-Durance (France)

    2015-07-01

    This study was carried out to understand the response of an eddy current type flowmeter in two phase liquid-metal flow. We use the technique of ellipse fit and correlate the fluctuations in the angle of inclination of this ellipse with the void fraction. The effects of physical parameters such as coil excitation frequency and flow velocity have been studied. The results show the possibility of using an eddy current flowmeter as a gas detector for large void fractions. (authors)

  18. Effect of endocrine treatment on voiding and prostate size in men with prostate cancer

    DEFF Research Database (Denmark)

    Klarskov, Louise L; Klarskov, Peter; Mommsen, Søren

    2012-01-01

    The aim of this study was to assess and quantify changes in voiding parameters and prostate size in men with prostate cancer from before the start of endocrine treatment and during long-term follow-up.......The aim of this study was to assess and quantify changes in voiding parameters and prostate size in men with prostate cancer from before the start of endocrine treatment and during long-term follow-up....

  19. Sodium void reactivity comparison for advanced liquid-metal reactor fuels

    Energy Technology Data Exchange (ETDEWEB)

    Dobbin, K.D.; Kessler, S.F.; Gedeon, S.R.; Omberg, R.P. (Westinghouse Hanford Co., Richland, WA (United States))

    1991-01-01

    The advanced liquid-metal reactor (ALMR) program in the US is based on metal as the reference fuel because of its favorable neutronic feedback characteristics for passive safety. Favorable relationships exist between core performance and safety that provide a passively safe metal fuel system with a large margin to sodium boiling. Because of this, the reduction of the positive sodium void coefficient of reactivity is not an overriding design objective. A positive sodium void effect with metal fuel is due to neutron spectral hardening that dominates capture and leakage changes during sodium voiding. This can produce as much as 5-$ positive sodium void reactivity for mixed plutonium-uranium fuel in a smaller core designed for a near-zero burnup reactivity swing. It is possible to reduce the positive void feedback and its effect on hypothetical loss-of-flow (LOF) scenarios with a commensurate increase in burnup swing. However, metal fuel's small Doppler coefficient, excellent fuel conductivity, and resultant small temperature gradients provide less reactivity feedback to handle postulated transient overpower (TOP) events for cores with significant burnup reactivity swings. The purpose of this work was to study the relationship between reduction of the sodium void and the resultant increase in the burnup reactivity swing for an ALMR modeled with metal, nitride, and oxide fuel.

  20. M-CHOLINOLYTICS IN RHEABILITATION OF CHILDREN WITH VOIDING DISFUNCTION AND URNARY BLADDER HYPERACTIVITY

    Directory of Open Access Journals (Sweden)

    I.V. Kazanskaya

    2006-01-01

    Full Text Available Voiding dysfunction is a common problem in pediatrics. Hyperactive urinary bladder is the most frequent cause of voiding dysfunction. Macholinolytic drugs are the first choice treatment for urinary bladder hyperactivity. The «urination pathology» center has investigated the efficacy of an macholinolytic, oxybutynin. The study included 25 children (aged 6–14 with different causes of voiding dysfunction and bladder hyperactivity. Oxybutynin was administered with a dosage of 5 mg twice a day, the follow up period was 8 weeks. The control evaluation of urodynamics (voiding rhythm, uroflowmetry, residual urine volume was performed at 4–8 weeks. Symptoms of bladder hyperactivity have been eliminated in 50% of patients, the bladder capacity has increased in 70% of cases, the frequency of night and day incontinence has diminished. The report demonstrates that oxybutynin has been most effective in patients with urinary bladder volume between 80 and 100 ml. the side effects, as dryness of mucous membranes and voiding difficulties, have been rarely observed. These side effects could be avoided by individual dose titration.Key words: voiding dysfunction, urinary bladder hyperactivity, oxybutynin, children.

  1. Electrochemical Behavior of CoNiCrAlY/ZrO2-Y2O3 Coated Layers with Atmospheric Pressure Plasma Technology in Seawater

    Science.gov (United States)

    Kim, Seong-Jong; Woo, Yong-Bin; Lee, Seung-Jun; Jeong, Jae-Yong

    2013-11-01

    Application of surface treatment has become common for protecting machine parts from oxidation, abrasion and corrosion induced by external environment. In particular, thermal spraying techniques are widely employed to improve wear, corrosion and thermal resistance. And compared to other methods they are simple and cost effective. However, the presence of porosity in the thermal spray coating can be highly detrimental because it provides access to penetration of corrosive matters, lowering corrosion resistance. Therefore, this research evaluate the electrochemical behavior under marine environment for aluminum-bronze alloy coated with MCrAlY and yttria-stabillized zirconia (YSZ) by atmospheric pressure plasma (APP) coating technology. Further application of carbon-based sealer removed voids and defects in the coating. The result reveled that, in case the voids and defects are completely removed, excellent corrosion resistance can be archived by application of good coating material along with formation of compact sealing layer.

  2. Self-cleaning behavior in polyurethane/silica coatings via formation of a hierarchical packed morphology of nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Hejazi, Iman [Department of Polymer Engineering & Color Technology, Amirkabir University of Technology, P.O. Box 15875/4413, Tehran (Iran, Islamic Republic of); Mir Mohamad Sadeghi, Gity, E-mail: Gsadeghi@aut.ac.ir [Department of Polymer Engineering & Color Technology, Amirkabir University of Technology, P.O. Box 15875/4413, Tehran (Iran, Islamic Republic of); Seyfi, Javad [Department of Chemical Engineering, Shahrood Branch, Islamic Azad University, P.O. Box 36155-163, Shahrood (Iran, Islamic Republic of); Jafari, Seyed-Hassan [School of Chemical Engineering, University of Tehran, P.O. Box 11155-4563, Tehran (Iran, Islamic Republic of); Khonakdar, Hossein Ali [Iran Polymer and Petrochemical Institute, P.O. Box 14965/115, Tehran (Iran, Islamic Republic of)

    2016-04-15

    Graphical abstract: - Highlights: • Self-cleaning behavior was imparted to the hydrophilic polyurethane. • A hierarchical packed morphology is responsible for the superhydrophobicity. • Prolonged pressing process cannot lead to superhydrophobicity due to migration of TPU. • Samples exhibited excellent stability against media with a wide range of pH values. - Abstract: In the current research, a hierarchical morphology comprising of packed assembly of nanoparticles was induced in thermoplastic polyurethane (TPU)/silica nanocomposite coatings in order to achieve self-cleaning behavior. Moderately hydrophilic behavior of TPU hinders its transforming to a superhydrophobic material. In the presented method, a very thin layer of silica nanoparticles is applied to the surface of TPU sheets under elevated temperature and pressure. As temperature and pressure of the process remain unchanged, processing time was considered as a main variable. Based on scanning electron microscopy and confocal microscopy results, it was found that at a certain processing time, nanoparticles can form an utterly packed morphology leading to a self-cleaning behavior. Once the process was prolonged, TPU macromolecules found the chance to migrate onto the coating's top layer due to the enhanced mobility of chains at high temperature. This observation was further proved by X-ray photoelectron spectroscopy analysis and cross-sectional morphology. The presented method has promising potentials in transforming intrinsically hydrophilic polymers into superhydrophobic materials with self-cleaning behavior.

  3. Inhibited phase behavior of gas hydrates in graphene oxide: influences of surface and geometric constraints.

    Science.gov (United States)

    Kim, Daeok; Kim, Dae Woo; Lim, Hyung-Kyu; Jeon, Jiwon; Kim, Hyungjun; Jung, Hee-Tae; Lee, Huen

    2014-11-07

    Porous materials have provided us unprecedented opportunities to develop emerging technologies such as molecular storage systems and separation mechanisms. Pores have also been used as supports to contain gas hydrates for the application in gas treatments. Necessarily, an exact understanding of the properties of gas hydrates in confining pores is important. Here, we investigated the formation of CO2, CH4 and N2 hydrates in non-interlamellar voids in graphene oxide (GO), and their thermodynamic behaviors. For that, low temperature XRD and P-T traces were conducted to analyze the water structure and confirm hydrate formation, respectively, in GO after its exposure to gaseous molecules. Confinement and strong interaction of water with the hydrophilic surface of graphene oxide reduce water activity, which leads to the inhibited phase behavior of gas hydrates.

  4. Noxious electrical stimulation of the pelvic floor and vagina induces transient voiding dysfunction in a rabbit survival model of pelvic floor dystonia.

    Science.gov (United States)

    Dobberfuhl, Amy D; Spettel, Sara; Schuler, Catherine; Levin, Robert M; Dubin, Andrew H; De, Elise J B

    2015-12-01

    Existing data supports a relationship between pelvic floor dysfunction and lower urinary tract symptoms. We developed a survival model of pelvic floor dysfunction in the rabbit and evaluated cystometric (CMG), electromyographic (EMG) and ambulatory voiding behavior. Twelve female adult virgin rabbits were housed in metabolic cages to record voiding and defecation. Anesthetized CMG/EMG was performed before and after treatment animals (n=9) received bilateral tetanizing needle stimulation to the pubococcygeous (PC) muscle and controls (n=3) sham needle placement. After 7 days all animals were subjected to tetanizing transvaginal stimulation and CMG/EMG. After 5 days a final CMG/EMG was performed. Of rabbits that underwent needle stimulation 7 of 9 (78%) demonstrated dysfunctional CMG micturition contractions versus 6 of 12 (50%) after transvaginal stimulation. Needle stimulation of the PC musculature resulted in significant changes in: basal CMG pressure, precontraction pressure change, contraction pressure, interval between contractions and postvoid residual; with time to 3rd contraction increased from 38 to 53 minutes (p=0.008 vs. prestimulation). Vaginal noxious stimulation resulted in significant changes in: basal CMG pressure and interval between contractions; with time to 3rd contraction increased from 37 to 46 minutes (p=0.008 vs. prestimulation). Changes in cage parameters were primarily seen after direct needle stimulation. In a majority of animals, tetanizing electrical stimulation of the rabbit pelvic floor resulted in voiding changes suggestive of pelvic floor dysfunction as characterized by a larger bladder capacity, longer interval between contractions and prolonged contraction duration.

  5. Effects of an Online Formative Peer-Tutoring Approach on Students' Learning Behaviors, Performance and Cognitive Load in Mathematics

    Science.gov (United States)

    Chu, Hui-Chun; Chen, Jun-Ming; Tsai, Chieh-Lun

    2017-01-01

    Mathematics has been widely recognized as being challenging for most students. In this study, an online formative peer-tutoring approach was proposed to cope with this problem, and an online learning system was developed accordingly. To evaluate the effectiveness of the proposed approach, an experiment was conducted to explore its effects on…

  6. Brief Report: Impression Formation in High-Functioning Autism--Role of Nonverbal Behavior and Stereotype Activating Information

    Science.gov (United States)

    Schwartz, Caroline; Dratsch, Thomas; Vogeley, Kai; Bente, Gary

    2014-01-01

    Little is known about whether stereotypes influence social judgments of autistic individuals, in particular when they compete with tacit face-to-face cues. We compared impression formation of 17 subjects with high-functioning autism (HFA) and 17 age-, gender- and IQ-matched controls. Information about the profession of a job applicant served as…

  7. The occurrence and behavior of radium in saline formation water of the U.S. Gulf Coast region.

    Science.gov (United States)

    Kraemer, T.F.; Reid, D.F.

    1984-01-01

    Ra was measured in deep saline formation waters produced from a variety of US Gulf Coast subsurface environments, including oil and gas reservoirs, and water-producing geopressured aquifers. A strong positive correlation was found between formation-water salinity and Ra activity, resulting from the interaction of formation water with aquifer matrix. Ra isotopes enter the fluid phase after being produced by the decay of parent elements U and Th on and within the solid matrix. The processes believed to be primarily responsible for transfering Ra from matrix to formation water are chemical leaching and alpha -particle recoil. Factors controlling the observed salinity-Ra relationship may be one or a combination of the following: 1) ion exchange; 2) increased solubility of matrix silica surrounding Ra atoms, coupled with a salinity-controlled rate of re-equilibration of silica between solution and quartz grains; and 3) the equilibration of Ra in solution with detrital baryte within the aquifer. No difference was found in the brine-Ra relation in water produced from oil or gas wells and water produced from wells penetrating only water-bearing aquifers, although the relation was more highly correlated for water-bearing aquifers than hydrocarbon-containing reservoirs.-P.Br.

  8. Interphase formation of a resin transfer molded silica phenolics composites subjected to dynamic impregnation process

    Science.gov (United States)

    Wang, Baichen; Huang, Yudong

    2008-05-01

    In this study interphase formation of a resin transfer molded (RTMed) silica-phenolics composites subjected to dynamic impregnation process was investigated. The solvent effect on the interphase formation of silica fiber-phenolics composites was evaluated. UV-vis spectra, XPS and electron paramagnetic resonance (EPR) techniques were used to characterize the competitive adsorption of the components of phenolics solution onto silica reinforcement surfaces. Interlaminar shear strength (ILSS) and void content of silica-phenolics composites were also measured. It has been found that phenolics forms distribution gradient over RTM mold with respect to isomeric composition under the effect of solvent, which result, to varying extent, in the inhomogeneity of void content and thus ILSS of a final product. For the first time, it has been shown that the RTM process of silica-phenolics composites is highly solvent-dependent. Our work gives an insight into the role of organic solvent in a RTM solution impregnation processing and provides useful information and trends relating microscopic to macroscopic behavior.

  9. Effect of the Heusler phase formation on the magnetic behavior of the Cu–10 wt.%Mn alloy with Al and Ag additions

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, T.M., E-mail: thaisa.mary@gmail.com [Instituto de Química – UNESP, Caixa Postal 355, 14801-970 Araraquara, SP (Brazil); Adorno, A.T.; Santos, C.M.A. [Instituto de Química – UNESP, Caixa Postal 355, 14801-970 Araraquara, SP (Brazil); Silva, R.A.G. [Departamento de Ciências Exatas e da Terra – UNIFESP, 09972-270 Diadema, SP (Brazil); Magnani, M. [Instituto de Química – UNESP, Caixa Postal 355, 14801-970 Araraquara, SP (Brazil)

    2015-09-15

    Highlights: • The presence of the Cu{sub 2}MnAl phase was observed in annealed alloys. • Al and Ag additions shift the equilibrium concentration to higher Al values. • There is a correlation between the Ag-rich phase and the Cu{sub 2}MnAl phase. - Abstract: In this work, the formation of the Cu{sub 2}AlMn Heusler phase and its influence on the magnetic behavior of the Cu–Mn–Al–Ag alloys in the range of 8–10 wt.% of aluminum and 2–4 wt.% of silver were studied using differential scanning calorimetry (DSC), transmission electron microscopy (TEM), high-resolution TEM (HRTEM) and saturation magnetization measurements at 4 K. The results showed that there is a correlation between the presence of the Ag-rich phase and the formation of the Cu{sub 2}MnAl phase.

  10. Formative Assessment of ARM-U: A Modular Intervention for Decreasing Risk Behaviors Among HIV-Positive and HIV-Negative Methamphetamine-Using MSM.

    Science.gov (United States)

    Garfein, Richard S; Metzner, Mitcheal; Cuevas, Jazmine; Bousman, Chad A; Patterson, Thomas

    2010-05-14

    Methamphetamine is a major contributor to HIV transmission among men who have sex with men (MSM). Recent studies show that up to one-third of methamphetamine-using MSM (MUMSM) inject the drug. We developed a behavioral intervention for MUMSM to decrease unprotected anal intercourse and increase awareness of parenteral HIV transmission risk. This 6-session (3 in-person, 3 by telephone) modular intervention was designed to be tailored to participants' HIV (+/-) and injection drug user ([IDU] yes/no) status. We present results of formative research used to evaluate the content and to assess feasibility and acceptability of this individual-level HIV risk-reduction intervention. HIV research clinic in a high MSM and methamphetamine prevalence neighborhood. Avoiding Risks from Methamphetamine-Use (ARM-U) is a brief toolbox intervention that allows counselors to select modules that suit a client's individual risk profile and intervention needs employing motivational interviewing and cognitive behavioral theory. We evaluated the format and content of the intervention through focus groups and pre-testing of the entire intervention using volunteers from the target population stratified into four groups (HIV+/IDU, HIV-/IDU, HIV+/non-IDU, HIV-/non-IDU). Four individuals in each stratum were recruited to undergo the intervention and complete a satisfaction survey at the end of each in-person session. In total, 25 MUMSM attended one of five focus groups. Participants thought all proposed intervention topics were important and could aid in reducing sexual risk behaviors among MUMSM. However, the neurocognitive effects of methamphetamine were reported to be a barrier to practicing safer sex, condom use negotiation or HIV status disclosure. Fifteen (94%) of 16 participants completed all 6 sessions and the satisfaction survey. On average, participants felt the intervention was useful for MUMSM, made them contemplate and move toward behavior change, and would recommend the program to

  11. Filling the void - enriching the feature space of successful stopping

    NARCIS (Netherlands)

    Huster, René J.; Schneider, Signe; Lavallee, Christina F.; Enriquez-Geppert, Stefanie; Herrmann, Christoph S.

    2017-01-01

    The ability to inhibit behavior is crucial for adaptation in a fast changing environment and is commonly studied with the stop signal task. Current EEG research mainly focuses on the N200 and P300 ERPs and corresponding activity in the theta and delta frequency range, thereby leaving us with a

  12. Generation of nano-voids inside polylactide using femtosecond laser radiation

    Science.gov (United States)

    Viertel, Tina; Pabst, Linda; Olbrich, Markus; Ebert, Robby; Horn, Alexander; Exner, Horst

    2017-12-01

    The arrangement of nanometer-sized voids, induced by focusing intense laser radiation within transparent material can allow the generation of transparent components with dimensions in the micrometer to nanometre range due to internal contour cut and thus satisfy the progressive miniaturization of products in micro-optics and medical technologies. For further improvements in the precision of those components, a deep understanding of the involved processes during the interaction of laser radiation within the material is necessary. In this work, voids inside bulk polylactide (PLA), a bioabsorbable polymer, were generated using a femtosecond laser ( λ = 1030 nm, τH = 180 fs) with single and multiple pulse irradiation. The dependence of the spot size was examined by the use of four microscope objectives with focus radii of 4.9, 3.3, 2 and 1.2 µm. For the experiments, the pulse energy and focusing depth into the material were varied. The dimensions of the voids were experimentally determined as function of the intensity. Differences in the lateral and axial extents of the voids were obtained for different focus radii and focusing depths at same intensities. Furthermore, the intensity distribution of the laser radiation inside the material for the different focus radii and focusing depths, and their dependence on the lateral and axial sizes of the voids was simulated and compared with the experimental results.

  13. Non-invasive evaluation of voiding function in asymptomatic primary school children.

    Science.gov (United States)

    Dogan, Hasan Serkan; Akpinar, Burcu; Gurocak, Serhat; Akata, Deniz; Bakkaloglu, Mehmet; Tekgul, Serdar

    2008-07-01

    This study aimed to evaluate the voiding characteristics of primary school children by using questionnaires and non-invasive diagnostic tools. The voiding characteristics of 212 healthy children in two primary schools were evaluated with ultrasound for bladder wall thickness (BWT) in association with the Pediatric Lower Urinary Tract Symptom Score (PLUTSS), familial questionnaire, uroflowmetry (UF) and urinalysis. Most of the children (70%) had achieved urinary and fecal continence between the ages of 18 months and 36 months. Twenty-five per cent of healthy children void fewer than four times or more than seven times per day. Ninety percent of children had a PLUTSS within normal ranges (< 9). Fifteen percent of patients had a uroflowmetric pattern other than bell-shaped. The peak and average flow rates were higher in girls. Enuresis nocturna was detected in 10% of children. None of the children had documented urinary tract infection. The average BWT from posterior wall at full bladder in healthy children was 1.1 mm. The anterior and posterior BWT measurements before and after micturition were found to be thicker in boys. Regarding the UF pattern, in post-voiding measurements in children with abnormal UF pattern, the bladder walls were thicker. Non-invasive tests in non-symptomatic children showed a range of variability, and these deviations should be kept in mind during the evaluation of voiding characteristics of a child. The symptom scoring system, with the high sensitivity and specificity rates it possesses, is one of the promising tools for this purpose.

  14. Globally Conservative, Hybrid Self-Adjoint Angular Flux and Least-Squares Method Compatible with Void

    CERN Document Server

    Laboure, Vincent M; Wang, Yaqi

    2016-01-01

    In this paper, we derive a method for the second-order form of the transport equation that is both globally conservative and compatible with voids, using Continuous Finite Element Methods (CFEM). The main idea is to use the Least-Squares (LS) form of the transport equation in the void regions and the Self-Adjoint Angular Flux (SAAF) form elsewhere. While the SAAF formulation is globally conservative, the LS formulation need a correction in void. The price to pay for this fix is the loss of symmetry of the bilinear form. We first derive this Conservative LS (CLS) formulation in void. Second we combine the SAAF and CLS forms and end up with an hybrid SAAF-CLS method, having the desired properties. We show that extending the theory to near-void regions is a minor complication and can be done without affecting the global conservation of the scheme. Being angular discretization agnostic, this method can be applied to both discrete ordinates (SN) and spherical harmonics (PN) methods. However, since a globally conse...

  15. Age problem in Lemaître–Tolman–Bondi void models

    Directory of Open Access Journals (Sweden)

    Xiao-Peng Yan

    2015-03-01

    Full Text Available As is well known, one can explain the current cosmic acceleration by considering an inhomogeneous and/or anisotropic universe (which violates the cosmological principle, without invoking dark energy or modified gravity. The well-known one of this kind of models is the so-called Lemaître–Tolman–Bondi (LTB void model, in which the universe is spherically symmetric and radially inhomogeneous, and we are living in a locally underdense void centered nearby our location. In the present work, we test various LTB void models with some old high redshift objects (OHROs. Obviously, the universe cannot be younger than its constituents. We find that an unusually large r0 (characterizing the size of the void is required to accommodate these OHROs in LTB void models. There is a serious tension between this unusually large r0 and the much smaller r0 inferred from other observations (e.g. SNIa, CMB and so on. However, if we instead consider the lowest limit 1.7 Gyr for the quasar APM 08279+5255 at redshift z=3.91, this tension could be greatly alleviated.

  16. Searching for Dwarf H Alpha Emission-line Galaxies within Voids III: First Spectra

    Science.gov (United States)

    Moody, J. Ward; Draper, Christian; McNeil, Stephen; Joner, Michael D.

    2017-02-01

    The presence or absence of dwarf galaxies with {M}r\\prime > -14 in low-density voids is determined by the nature of dark matter halos. To better understand what this nature is, we are conducting an imaging survey through redshifted Hα filters to look for emission-line dwarf galaxies in the centers of two nearby galaxy voids called FN2 and FN8. Either finding such dwarfs or establishing that they are not present is a significant result. As an important step in establishing the robustness of the search technique, we have observed six candidates from the survey of FN8 with the Gillett Gemini telescope and GMOS spectrometer. All of these candidates had emission, although none was Hα. The emission in two objects was the [O iii]λ4959, 5007 doublet plus Hβ, and the emission in the remaining four was the [O ii]λ3727 doublet, all from objects beyond the void. While no objects were within the void, these spectra show that the survey is capable of finding emission-line dwarfs in the void centers that are as faint as {M}r\\prime ˜ -12.4, should they be present. These spectra also show that redshifts estimated from our filtered images are accurate to several hundred km s-1 if the line is identified correctly, encouraging further work in finding ways to conduct redshift surveys through imaging alone.

  17. Critical velocities for deflagration and detonation triggered by voids in a REBO high explosive

    Energy Technology Data Exchange (ETDEWEB)

    Herring, Stuart Davis [Los Alamos National Laboratory; Germann, Timothy C [Los Alamos National Laboratory; Jensen, Niels G [Los Alamos National Laboratory

    2010-01-01

    The effects of circular voids on the shock sensitivity of a two-dimensional model high explosive crystal are considered. We simulate a piston impact using molecular dynamics simulations with a Reactive Empirical Bond Order (REBO) model potential for a sub-micron, sub-ns exothermic reaction in a diatomic molecular solid. The probability of initiating chemical reactions is found to rise more suddenly with increasing piston velocity for larger voids that collapse more deterministically. A void with radius as small as 10 nm reduces the minimum initiating velocity by a factor of 4. The transition at larger velocities to detonation is studied in a micron-long sample with a single void (and its periodic images). The reaction yield during the shock traversal increases rapidly with velocity, then becomes a prompt, reliable detonation. A void of radius 2.5 nm reduces the critical velocity by 10% from the perfect crystal. A Pop plot of the time-to-detonation at higher velocities shows a characteristic pressure dependence.

  18. Chewing Prevents Stress-Induced Hippocampal LTD Formation and Anxiety-Related Behaviors: A Possible Role of the Dopaminergic System

    Directory of Open Access Journals (Sweden)

    Yumie Ono

    2015-01-01

    Full Text Available The present study examined the effects of chewing on stress-induced long-term depression (LTD and anxiogenic behavior. Experiments were performed in adult male rats under three conditions: restraint stress condition, voluntary chewing condition during stress, and control condition without any treatments except handling. Chewing ameliorated LTD development in the hippocampal CA1 region. It also counteracted the stress-suppressed number of entries to the center region of the open field when they were tested immediately, 30 min, or 60 min after restraint. At the latter two poststress time periods, chewing during restraint significantly increased the number of times of open arm entries in the elevated plus maze, when compared with those without chewing. The in vivo microdialysis further revealed that extracellular dopamine concentration in the ventral hippocampus, which is involved in anxiety-related behavior, was significantly greater in chewing rats than in those without chewing from 30 to 105 min after stress exposure. Development of LTD and anxiolytic effects ameliorated by chewing were counteracted by administering the D1 dopamine receptor antagonist SCH23390, which suggested that chewing may activate the dopaminergic system in the ventral hippocampus to suppress stress-induced anxiogenic behavior.

  19. Using Directional Diffusion Coefficients for Nonlinear Diffusion Acceleration of the First Order SN Equations in Near-Void Regions

    Energy Technology Data Exchange (ETDEWEB)

    Schunert, Sebastian; Hammer, Hans; Lou, Jijie; Wang, Yaqi; Ortensi, Javier; Gleicher, Frederick; Baker, Benjamin; DeHart, Mark; Martineau, Richard

    2016-11-01

    The common definition of the diffusion coeffcient as the inverse of three times the transport cross section is not compat- ible with voids. Morel introduced a non-local tensor diffusion coeffcient that remains finite in voids[1]. It can be obtained by solving an auxiliary transport problem without scattering or fission. Larsen and Trahan successfully applied this diffusion coeffcient for enhancing the accuracy of diffusion solutions of very high temperature reactor (VHTR) problems that feature large, optically thin channels in the z-direction [2]. It is demonstrated that a significant reduction of error can be achieved in particular in the optically thin region. Along the same line of thought, non-local diffusion tensors are applied modeling the TREAT reactor confirming the findings of Larsen and Trahan [3]. Previous work of the authors have introduced a flexible Nonlinear-Diffusion Acceleration (NDA) method for the first order S N equations discretized with the discontinuous finite element method (DFEM), [4], [5], [6]. This NDA method uses a scalar diffusion coeffcient in the low-order system that is obtained as the flux weighted average of the inverse transport cross section. Hence, it su?ers from very large and potentially unbounded diffusion coeffcients in the low order problem. However, it was noted that the choice of the diffusion coeffcient does not influence consistency of the method at convergence and hence the di?usion coeffcient is essentially a free parameter. The choice of the di?usion coeffcient does, however, affect the convergence behavior of the nonlinear di?usion iterations. Within this work we use Morel’s non-local di?usion coef- ficient in the aforementioned NDA formulation in lieu of the flux weighted inverse of three times the transport cross section. The goal of this paper is to demonstrate that significant en- hancement of the spectral properties of NDA can be achieved in near void regions. For testing the spectral properties of the NDA

  20. Detection of underground voids in Tahura Japan Cave Bandung using ground penetrating radar

    Science.gov (United States)

    Azimmah, Azizatun; Widodo

    2017-07-01

    The detection of underground voids is important due to their effects on subsidence higher risk. Ground Penetrating Radar is one of geophysical electromagnetic methods that has been proven to be able to detect and locate any void beneath the surface effectively at a shallow depth. This method uses the contrasts of dielectric properties, resistivity and magnetic permeability to investigate and map what lies beneath the surface. Hence, this research focused on how GPR could be applied for detecting underground voids at the site of investigation, The Japan Cave in Taman Hutan Raya located in Dago, Bandung, Indonesia. A 100 MHz GPR shielded antenna frequency were used to measure three >80 meters long measurement lines. These three GPR profiles were positioned on the surface above the Japan Cave. The radargram results showed existences of different amplitude regions proven to be the air-filled cavities, at a depth of <10 meters, and interfaces between the underneath layers.

  1. [Serial voiding urosonography: a safe technique for the study of the entire urinary tract in children].

    Science.gov (United States)

    Duran, C; del Riego, J; Riera, L

    2013-01-01

    For more than a decade, serial voiding urosonography has been one of the imaging modalities used to detect vesicoureteral reflux in children and it is now also used to study the urethra. The main advantage of this technique is it does not irradiate. Given the important recognition of serial voiding urosonography by the European Society of Pediatric Radiology at the last congress in May 2011, we think it is useful to describe how to carry out this technique successfully. In this update on serial voiding urosonography, we describe the indications, the entire procedure, and the different characteristics of this technique, which we understand will soon become the technique of choice for screening for vesicoureteral reflux as well as for urethral pathology in children. Copyright © 2011 SERAM. Published by Elsevier Espana. All rights reserved.

  2. Evaluation and Comparison of Freeze-Thaw Tests and Air Void Analysis of Pervious Concrete

    DEFF Research Database (Denmark)

    Lund, Mia Schou Møller; Hansen, Kurt Kielsgaard; Kevern, John T.

    2016-01-01

    Pearl-Chain Bridge technology is an innovative precast arch bridge solution which uses pervious concrete as fill material. To ensure longevity of the bridge superstructure it is necessary that the per-vious concrete fill is designed to be freeze-thaw durable; however, no standards exist on how...... to eval-uate the freeze-thaw resistance of fresh or hardened pervious concrete and correspondingly what constitutes acceptable freeze-thaw durability. A greater understanding of the correlation between the freeze-thaw performance and the air void structure of pervious concrete is needed. In the present...... study six pervious concrete mixes were exposed to freeze-thaw testing, and their air void structure was analyzed using an automated linear-traverse method. It was found that there is a miscorrelation between these two test methods in their assumption of whether or not the large interconnected voids...

  3. Iteration and extrapolation methods for the approximate solution of the even-parity transport equation for systems with voids

    Energy Technology Data Exchange (ETDEWEB)

    Ackroyd, R.T. (Queen Mary Coll., London (UK). Dept. of Nuclear Engineering); Riyait, N.S. (Imperial Coll. of Science and Technology, London (UK). Nuclear Power Group)

    1989-01-01

    Conventional finite-element solutions of the even-parity transport equation for systems with voids treat the void as a region of low absorption. This treatment tends to give physically-unacceptable solutions to void problems as the void cross-section tends to zero. An explanation for the effect is proposed. Biased finite elements are used in two ways to obtain physically-acceptable solutions for the void regions. Two new methods are described and tested. The iterative method synthesizes finite-element solution using a sequence of problems with constant absorptions in the void regions. The sequence is terminated when the fluxes in the void regions become steady. The extrapolation method obtains a best approximation to the void solution by combining two or more independent biased trial functions in an optimum way. The extrapolation method is further subdivided into elementary and nodal or multiparameter extrapolation. The relevant theory of both the iteration and extrapolation methods is given. Several 2-D test problems using the above methods have been investigated. Results are compared with those obtained with other numerical methods and almost analytical results of the point kernel method for voids surrounded by purely absorbing media. (author).

  4. Axial-Compressive Behavior, Including Kink-Band Formation and Propagation, of Single p-Phenylene Terephthalamide (PPTA Fibers

    Directory of Open Access Journals (Sweden)

    M. Grujicic

    2013-01-01

    Full Text Available The mechanical response of p-phenylene terephthalamide (PPTA single fibers when subjected to uniaxial compression is investigated computationally using coarse-grained molecular statics/dynamics methods. In order to construct the coarse-grained PPTA model (specifically, in order to define the nature of the coarse-grained particles/beads and to parameterize various components of the bead/bead force-field functions, the results of an all-atom molecular-level computational investigation are used. In addition, the microstructure/topology of the fiber core, consisting of a number of coaxial crystalline fibrils, is taken into account. Also, following our prior work, various PPTA crystallographic/topological defects are introduced into the model (at concentrations consistent with the prototypical PPTA synthesis/processing conditions. The analysis carried out clearly revealed (a formation of the kink bands during axial compression; (b the role of defects in promoting the formation of kink bands; (c the stimulating effects of some defects on the fiber-fibrillation process; and (d the detrimental effect of the prior compression, associated with fiber fibrillation, on the residual longitudinal-tensile strength of the PPTA fibers.

  5. S-Lagrangian dynamics of many-body systems and behavior of social groups: Dominance and hierarchy formation

    Science.gov (United States)

    Sandler, U.

    2017-11-01

    In this paper, we extend our generalized Lagrangian dynamics (i.e., S-Lagrangian dynamics, which can be applied equally to physical and non-physical systems as per Sandler (2014)) to many-body systems. Unlike common Lagrangian dynamics, this is not a trivial task. For many-body systems with S-dependent Lagrangians, the Lagrangian and the corresponding Hamiltonian or energy become vector functions, conjugated momenta become second-order tensors, and the system inevitably develops a hierarchical structure, even if all bodies initially have similar status and Lagrangians. As an application of our theory, we consider dominance and hierarchy formation, which is present in almost all communities of living species. As a biological basis for this application, we assume that the primary motivation of a groups activity is to attempt to cope with stress arising as pressure from the environment and from intrinsic unmet needs of individuals. It has been shown that the S-Lagrangian approach to a group's evolution naturally leads to formation of linear or despotic dominance hierarchies, depending on differences between individuals in coping with stress. That is, individuals that cope more readily with stress take leadership roles during the evolution. Experimental results in animal groups which support our assumption and findings are considered.

  6. Filling the voids in the SRTM elevation model — A TIN-based delta surface approach

    Science.gov (United States)

    Luedeling, Eike; Siebert, Stefan; Buerkert, Andreas

    The Digital Elevation Model (DEM) derived from NASA's Shuttle Radar Topography Mission is the most accurate near-global elevation model that is publicly available. However, it contains many data voids, mostly in mountainous terrain. This problem is particularly severe in the rugged Oman Mountains. This study presents a method to fill these voids using a fill surface derived from Russian military maps. For this we developed a new method, which is based on Triangular Irregular Networks (TINs). For each void, we extracted points around the edge of the void from the SRTM DEM and the fill surface. TINs were calculated from these points and converted to a base surface for each dataset. The fill base surface was subtracted from the fill surface, and the result added to the SRTM base surface. The fill surface could then seamlessly be merged with the SRTM DEM. For validation, we compared the resulting DEM to the original SRTM surface, to the fill DEM and to a surface calculated by the International Center for Tropical Agriculture (CIAT) from the SRTM data. We calculated the differences between measured GPS positions and the respective surfaces for 187,500 points throughout the mountain range (ΔGPS). Comparison of the means and standard deviations of these values showed that for the void areas, the fill surface was most accurate, with a standard deviation of the ΔGPS from the mean ΔGPS of 69 m, and only little accuracy was lost by merging it to the SRTM surface (standard deviation of 76 m). The CIAT model was much less accurate in these areas (standard deviation of 128 m). The results show that our method is capable of transferring the relative vertical accuracy of a fill surface to the void areas in the SRTM model, without introducing uncertainties about the absolute elevation of the fill surface. It is well suited for datasets with varying altitude biases, which is a common problem of older topographic information.

  7. Discovery of a big void in Khufu's Pyramid by observation of cosmic-ray muons.

    Science.gov (United States)

    Morishima, Kunihiro; Kuno, Mitsuaki; Nishio, Akira; Kitagawa, Nobuko; Manabe, Yuta; Moto, Masaki; Takasaki, Fumihiko; Fujii, Hirofumi; Satoh, Kotaro; Kodama, Hideyo; Hayashi, Kohei; Odaka, Shigeru; Procureur, Sébastien; Attié, David; Bouteille, Simon; Calvet, Denis; Filosa, Christopher; Magnier, Patrick; Mandjavidze, Irakli; Riallot, Marc; Marini, Benoit; Gable, Pierre; Date, Yoshikatsu; Sugiura, Makiko; Elshayeb, Yasser; Elnady, Tamer; Ezzy, Mustapha; Guerriero, Emmanuel; Steiger, Vincent; Serikoff, Nicolas; Mouret, Jean-Baptiste; Charlès, Bernard; Helal, Hany; Tayoubi, Mehdi

    2017-12-21

    The Great Pyramid, or Khufu's Pyramid, was built on the Giza plateau in Egypt during the fourth dynasty by the pharaoh Khufu (Cheops), who reigned from 2509 bc to 2483 bc. Despite being one of the oldest and largest monuments on Earth, there is no consensus about how it was built. To understand its internal structure better, we imaged the pyramid using muons, which are by-products of cosmic rays that are only partially absorbed by stone. The resulting cosmic-ray muon radiography allows us to visualize the known and any unknown voids in the pyramid in a non-invasive way. Here we report the discovery of a large void (with a cross-section similar to that of the Grand Gallery and a minimum length of 30 metres) situated above the Grand Gallery. This constitutes the first major inner structure found in the Great Pyramid since the nineteenth century. The void, named ScanPyramids' Big Void, was first observed with nuclear emulsion films installed in the Queen's chamber, then confirmed with scintillator hodoscopes set up in the same chamber and finally re-confirmed with gas detectors outside the pyramid. This large void has therefore been detected with high confidence by three different muon detection technologies and three independent analyses. These results constitute a breakthrough for the understanding of the internal structure of Khufu's Pyramid. Although there is currently no information about the intended purpose of this void, these findings show how modern particle physics can shed new light on the world's archaeological heritage.

  8. Habit formation.

    Science.gov (United States)

    Smith, Kyle S; Graybiel, Ann M

    2016-03-01

    Habits, both good ones and bad ones, are pervasive in animal behavior. Important frameworks have been developed to understand habits through psychological and neurobiological studies. This work has given us a rich understanding of brain networks that promote habits, and has also helped us to understand what constitutes a habitual behavior as opposed to a behavior that is more flexible and prospective. Mounting evidence from studies using neural recording methods suggests that habit formation is not a simple process. We review this evidence and take the position that habits could be sculpted from multiple dissociable changes in neural activity. These changes occur across multiple brain regions and even within single brain regions. This strategy of classifying components of a habit based on different brain signals provides a potentially useful new way to conceive of disorders that involve overly fixed behaviors as arising from different potential dysfunctions within the brain's habit network.

  9. Measurement of void fractions by nuclear techniques; Medicion de fracciones de vacio por tecnicas nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez G, A.; Vazquez G, J.; Diaz H, C.; Salinas R, G.A. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1997-07-01

    In this work it is done a general analysis of those techniques used to determine void fractions and it is chosen a nuclear technique to be used in the heat transfer circuit of the Physics Department of the Basic Sciences Management. The used methods for the determination of void fractions are: radioactive absorption, acoustic techniques, average velocity measurement, electromagnetic flow measurement, optical methods, oscillating absorption, nuclear magnetic resonance, relation between pressure and flow oscillation, infrared absorption methods, sound neutron analysis. For the case of this work it will be treated about the radioactive absorption method which is based in the gamma rays absorption. (Author)

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

    DEFF Research Database (Denmark)

    Golubov, S.I.; Singh, Bachu Narain; Trinkaus, H.

    2000-01-01

    in Part I of this paper (Singh, Eldrup, Horsewell, Ehrhart and Dworschak 2000). The present paper attempts to provide a theoretical framework within which theeffect of recoil energy on damage accumulation behaviour can be understood. The damage accumulation under Frenkel pair production (e.g. 2.5 Me...... such asone-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 thecase of Frenkel pair production, the experimental...

  11. Propagation of Love waves in a void medium over a sandy half space under gravity

    Science.gov (United States)

    Patra, Pulak; Gupta, Asit Kumar; Kundu, Santimoy

    2017-04-01

    The present study investigates the propagation of Love wave in a void layer resting over a sandy half space under the effect of gravitational force. The equations of motion have been gathered separately for different layers, and the boundary conditions have been introduced for two different layers at their interface. The mathematical analysis of the problem has been dealt with the help of Whittaker's function by expanding it asymptotically up to linear terms. The study reveals that in such a situation there exist two different wave fronts for the two above-mentioned layers: one is for the effects of gravity and sandy parameters, whereas other is for the effect of void parameter.

  12. Numerical test of the open void method of slide line with unstructured polygon grids

    Science.gov (United States)

    Lin, Wenzhou; Lin, Zhong; Liu, Quan

    2017-07-01

    An open void method of slide line is developed based on unstructured arbitrary polygon grids. An method of distinguishing open or closed void state of node and grid, and calculation method of velocity of node in slide line is given with open or closed state. Many conditions including different kinds of grids, different velocity and multi-medium are simulated in a test of a metallic flyer impacting another flyer and then separating. A test of Detonation driving metallic flyer are is simulated, which prove the rationality and adaptability of method.

  13. Idiopathic detrusor sphincter dyssynergia in neurologically normal patients with voiding abnormalities

    DEFF Research Database (Denmark)

    Jørgensen, T M; Djurhuus, J C; Schrøder, H D

    1982-01-01

    Symptomatology and clinical manifestations of detrusor sphincter dyssynergia are described in 23 patients without neurological disease. Their cardinal symptoms were recurrent cystitis, enuresis, frequent voiding, back pain during voiding and anal discomfort. The major objective finding...... was vesicoureteral reflux in 11 cases with kidney scarring in 10. Bladder trabeculation was found in 13 patients, bladder hyperreflexia in 8, and significant residual urine in 16 patients. The etiology of detrusor sphincter dyssynergia in non-neurological patients is discussed. By means of exclusion it is most...

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

    KAUST Repository

    Liu, Junxian

    2014-09-25

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

  15. Recurring priapism may be a symptom of voiding dysfunction – case report and literature review

    Directory of Open Access Journals (Sweden)

    Lisieux Eyer de Jesus

    2016-04-01

    Full Text Available ABSTRACT Recurring priapism is rare in pre-pubertal children and may be attributed to multiple causes. We propose that voiding dysfunction (VD may also justify this symptom and detail a clinical case of recurring stuttering priapism associated to overactive bladder that completely resolved after usage of anticholinergics and urotherapy. Sacral parasympathetic activity is responsible for detrusor contraction and for spontaneous erections and a relationship between erections and bladder status has been proved in healthy subjects (morning erections and models of medullar trauma. High bladder pressures and/or volumes, voiding incoordination and posterior urethritis can potentially trigger reflex erections.

  16. Nonverbal behavior in soccer: the influence of dominant and submissive body language on the impression formation and expectancy of success of soccer players.

    Science.gov (United States)

    Furley, Philip; Dicks, Matt; Memmert, Daniel

    2012-02-01

    In the present article, we investigate the effects of specific nonverbal behaviors signaling dominance and submissiveness on impression formation and outcome expectation in the soccer penalty kick situation. In Experiment 1, results indicated that penalty takers with dominant body language are perceived more positively by soccer goalkeepers and players and are expected to perform better than players with a submissive body language. This effect was similar for both video and point-light displays. Moreover, in contrast to previous studies, we found no effect of clothing (red vs. white) in the video condition. In Experiment 2, we used the implicit association test to demonstrate that dominant body language is implicitly associated with a positive soccer player schema whereas submissive body language is implicitly associated with a negative soccer player schema. The implications of our findings are discussed with reference to future implications for theory and research in the study of person perception in sport.

  17. PLUVIUS: a generalized one-dimensional model of reactive pollutant behavior, including dry deposition, precipitation formation, and wet removal. Second edition

    Energy Technology Data Exchange (ETDEWEB)

    Easter, R.C.; Hales, J.M.

    1984-11-01

    This report is a second-edition user's manual for the PLUVIUS reactive-storm model. The PLUVIUS code simulates the formation of storm systems of a variety of types, and characterizes the behavior of air pollutants as they flow through, react within, and are scavenged by the storms. The computer code supplied with this report is known as PLUVIUS MOD 5.0, and is a substantial improvement over the MOD 3.1 version given in the original user's manual. Example applications of MOD 5.0 are given in the report to facilitate rapid application of the code for a variety of specific uses. 22 references, 7 figures, 48 tables.

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

    DEFF Research Database (Denmark)

    Singh, Bachu Narain; Eldrup, Morten Mostgaard; Zinkle, S.J.

    2002-01-01

    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. The phenomenon had already been investigated in the 1970s and it was demonstrated that the grain-size-dependent v...

  19. Maintaining Low Voiding Solder Die Attach for Power Die While Minimizing Die Tilt

    Energy Technology Data Exchange (ETDEWEB)

    Hamm, Randy; Peterson, Kenneth A.

    2015-10-01

    This paper addresses work to minimize voiding and die tilt in solder attachment of a large power die, measuring 9.0 mm X 6.5 mm X 0.1 mm (0.354” x 0.256” x 0.004”), to a heat spreader. As demands for larger high power die continue, minimizing voiding and die tilt is of interest for improved die functionality, yield, manufacturability, and reliability. High-power die generate considerable heat, which is important to dissipate effectively through control of voiding under high thermal load areas of the die while maintaining a consistent bondline (minimizing die tilt). Voiding was measured using acoustic imaging and die tilt was measured using two different optical measurement systems. 80Au-20Sn solder reflow was achieved using a batch vacuum solder system with optimized fixturing. Minimizing die tilt proved to be the more difficult of the two product requirements to meet. Process development variables included tooling, weight and solder preform thickness.

  20. VizieR Online Data Catalog: Galaxies in the Lynx-Cancer void (Pustilnik+, 2011)

    Science.gov (United States)

    Pustilnik, S. A.; Tepliakova, A. L.

    2012-02-01

    The evolution of galaxies is influenced by the environment in which they reside. This effect should be strongest for the lowest-mass and lowest-luminosity galaxies. To study dwarf galaxies in extremely low density environments, we have compiled a deep catalogue of dwarf galaxies in the nearby Lynx-Cancer void. This void hosts some of the most metal-poor dwarfs known to date. It borders the Local Volume at negative supergalactic Z(SGZ) coordinates and has a size of more than 16Mpc. With a distance to its centre of only 18Mpc, it is close enough to allow a search for the faintest dwarfs. Within the void 75 dwarf (-11.9>MB>-18.0) and four subluminous (-18.0>MB>-18.4) galaxies have been identified. We present the parameters of the void galaxies and a detailed analysis of the completeness of the catalogue as a function of magnitude and surface brightness. (3 data files).

  1. A viscoplastic strain gradient analysis of materials with voids or inclusions

    DEFF Research Database (Denmark)

    Borg, Ulrik; Niordson, Christian Frithiof; Fleck, N. A.

    2006-01-01

    . It is shown how the model predicts increased overall yield strength, as compared to conventional predictions, when voids or inclusions are in the micron range. Furthermore, it is illustrated how the higher order boundary conditions at the interface between inclusions and matrix material are important...

  2. EDOVE: Energy and Depth Variance-Based Opportunistic Void Avoidance Scheme for Underwater Acoustic Sensor Networks.

    Science.gov (United States)

    Bouk, Safdar Hussain; Ahmed, Syed Hassan; Park, Kyung-Joon; Eun, Yongsoon

    2017-09-26

    Underwater Acoustic Sensor Network (UASN) comes with intrinsic constraints because it is deployed in the aquatic environment and uses the acoustic signals to communicate. The examples of those constraints are long propagation delay, very limited bandwidth, high energy cost for transmission, very high signal attenuation, costly deployment and battery replacement, and so forth. Therefore, the routing schemes for UASN must take into account those characteristics to achieve energy fairness, avoid energy holes, and improve the network lifetime. The depth based forwarding schemes in literature use node's depth information to forward data towards the sink. They minimize the data packet duplication by employing the holding time strategy. However, to avoid void holes in the network, they use two hop node proximity information. In this paper, we propose the Energy and Depth variance-based Opportunistic Void avoidance (EDOVE) scheme to gain energy balancing and void avoidance in the network. EDOVE considers not only the depth parameter, but also the normalized residual energy of the one-hop nodes and the normalized depth variance of the second hop neighbors. Hence, it avoids the void regions as well as balances the network energy and increases the network lifetime. The simulation results show that the EDOVE gains more than 15 % packet delivery ratio, propagates 50 % less copies of data packet, consumes less energy, and has more lifetime than the state of the art forwarding schemes.

  3. Voids in static neutron stars via a second solution of the Einstein field equations

    Science.gov (United States)

    Kiess, Thomas E.

    2017-07-01

    We show that voids can exist inside neutron stars modeled as static spherically symmetric perfect fluid masses, enabled by a second massless solution of the Einstein Field Equations that produces pressure and that is physically permissible in the interior. The boundary between this interior massless solution and hadronic matter is analogous to a phase transition, in effect truncating the equation of state at a critical pressure. We exhibit the interior massless solution and apply it to a Tolman VII neutron star with a physical equation of state, and show that applicable boundary conditions are satisfied. As a result of numerical modeling, we show that void volumes corresponding to internal densities greater than ˜5 times the surface density are physically plausible and energetically favorable but only perturb the stellar mass, external radius, interior redshifts, and moments of inertia, making such observables not very definitive signatures. We conclude that cold neutron stars may contain these interior voids, as intriguing metric solutions of the Einstein Field Equations in classical general relativity, but the size and influence of such voids on observables can be larger for denser more compact objects (e.g., strange quark stars or black holes).

  4. Influence of bulk dielectric polarization upon partial discharge transients: Effect of void geometry and orientation

    DEFF Research Database (Denmark)

    McAllister, Iain Wilson; Crichton, G.C.

    2005-01-01

    The induced charge arising from a partial discharge consists of 2 components. One is associated with the actual space charge in the void. The other is related to changes in the polarization of the bulk dielectric. These changes are a direct consequence of the field produced by the space charge. T...

  5. VizieR Online Data Catalog: Lynx-Cancer void sample galaxies HI data (Pustilnik+, 2016)

    Science.gov (United States)

    Pustilnik, S. A.; Martin, J.-M.

    2017-03-01

    The HI observations were made during the period 2007-2013 with the Nancay Radio Telescope (NRT). In Table A.1 we present the main parameters taken from NED1, SDSS2 or from the literature for all observed 45 void galaxies. ************************************************************************** * * * Sorry, but the author(s) never supplied the fits spectra as * * announced in the paper * * * ************************************************************************** (3 data files).

  6. Voids and porosities in class I micropreparations filled with various resin composites.

    NARCIS (Netherlands)

    Opdam, N.J.M.; Roeters, F.J.M.; Boer, T. de; Pesschier, D.; Bronkhorst, E.M.

    2003-01-01

    In this in vitro study, voids inside a minimal occlusal restoration using different consistencies of resin composite and various application techniques were investigated. One hundred and fifty-two simulated, minimally invasive preparations, including a prepared fissure and an excavated carious

  7. Particle-size distribution and void fraction of geometric random packings

    NARCIS (Netherlands)

    Brouwers, Jos

    2006-01-01

    This paper addresses the geometric random packing and void fraction of polydisperse particles. It is demonstrated that the bimodal packing can be transformed into a continuous particle-size distribution of the power law type. It follows that a maximum packing fraction of particles is obtained when

  8. A RELATION FOR THE VOID FRACTION OF RANDOMLY PACKED PARTICLE BEDS

    NARCIS (Netherlands)

    HOFFMANN, AC; FINKERS, HJ

    The void fractions of loosely packed and tapped beds of particles of continuous size distributions are correlated by means of a proposed new semi-empirical relation. In this relation four parameters describing the following particle properties are included: (i) mean particle size, (ii) spread of the

  9. Prolonged irritative voiding symptoms due to Enterobius vermicularis bladder infestation in an adult patient.

    Science.gov (United States)

    Sammour, Zein Mohamed; Gomes, Cristiano Mendes; Tome, Andre Luiz Farinhas; Bruschini, Homero; Srougi, Miguel

    2008-08-01

    Enterobius vermicularis (pinworm) is one of the most prevalent intestinal parasites in the world. The urinary tract is rarely affected and few cases have been reported. We report a case of bladder infestation by mature female worms of E. vermicularis in a woman presenting with irritative voiding symptoms.

  10. Prolonged irritative voiding symptoms due to Enterobius vermicularis bladder infestation in an adult patient

    Directory of Open Access Journals (Sweden)

    Zein Mohamed Sammour

    Full Text Available Enterobius vermicularis (pinworm is one of the most prevalent intestinal parasites in the world. The urinary tract is rarely affected and few cases have been reported. We report a case of bladder infestation by mature female worms of E. vermicularis in a woman presenting with irritative voiding symptoms.

  11. Void Volume Swelling Dependent on Grain Size in Austenitic Stainless Steel

    DEFF Research Database (Denmark)

    Singh, Bachu Narain

    1973-01-01

    Describes some of the main findings of a systematic study of the effect of grain size on the void volume swelling. In this study a powder-produced 20 Ni/20 Cr austenitic stainless steel, with 0.02% carbon and without carbide-forming elements was used. Some specimens containing dispersions...

  12. On recoil energy dependent void swelling in pure copper: part 1, experimental results

    DEFF Research Database (Denmark)

    Singh, B.N.; Eldrup, M.; Horsewell, Andy

    2000-01-01

    In recent years, the problem of void swelling has been treated within the framework of production bias model (PBM). The model considers the intracascade clustering of vacancies and self-interstitial atoms (SIAs), their thermal stability and the resulting asymmetry in the production of free and mo...

  13. ICS teaching module : Analysis of voiding, pressure flow analysis (basic module)

    NARCIS (Netherlands)

    Rosier, Peter F W M; Kirschner-Hermanns, Ruth; Svihra, Jan; Homma, Yukio; Wein, Alan J.

    2016-01-01

    Aims To present the evidence background for an ICS teaching module for the urodynamic analysis of voiding. Methods Literature analysis and expert opinion are combined to collate an outline and explanation of a preferred and good urodynamic practice. Result Patient's preparation, pathophysiology,

  14. Emerging Economies, Institutional Voids, and Innovation Drivers : A Study in India

    NARCIS (Netherlands)

    Voeten, Jaap; Saiyed, Abrar Ali; Dutta, Dev K.

    Research has highlighted the importance of the institutional context on innovation and entrepreneurship. The focus of this qualitative research was to study small and medium enterprises (SMEs) in the manufacturing sector in India with the purpose of understanding how institutional voids affect the

  15. 40 CFR 86.614-84 - Hearings on suspension, revocation, and voiding of certificates of conformity.

    Science.gov (United States)

    2010-07-01

    ..., and voiding of certificates of conformity. 86.614-84 Section 86.614-84 Protection of Environment... certificates of conformity. (a) Applicability. The procedures prescribed by this section apply whenever a... or revoke a certificate of conformity was made under § 86.612(d) prior to the decision to deny the...

  16. Repeatability of post-void residual urine ≥ 100 ml in urogynaecologic patients

    DEFF Research Database (Denmark)

    Saaby, Marie-Louise; Lose, Gunnar

    2012-01-01

    Post-void residual urine (PVR) is a key variable in the assessment of the emptying function of the lower urinary tract and is often used as an outcome measure after treatment. Increased PVR can lead to further investigation and treatment, or cancellation of planned incontinence surgery...

  17. Formation and coalescence of strain localized regions in ferrite phase of DP600 steels under uniaxial tensile deformation

    Energy Technology Data Exchange (ETDEWEB)

    Alaie, A., E-mail: amir_alaie@yahoo.com [Department of Mechanical Engineering, Isfahan University of Technology, Isfahan (Iran, Islamic Republic of); Kadkhodapour, J. [Department of Mechanical Engineering, Shahid Rajaee Teacher Training University, Tehran (Iran, Islamic Republic of); Institute for Materials Testing, Materials Science and Strength of Materials (IMWF), University of Stuttgart, Stuttgart (Germany); Ziaei Rad, S. [Department of Mechanical Engineering, Isfahan University of Technology, Isfahan (Iran, Islamic Republic of); Asadi Asadabad, M. [Materials Research School, Isfahan (Iran, Islamic Republic of); Schmauder, S. [Institute for Materials Testing, Materials Science and Strength of Materials (IMWF), University of Stuttgart, Stuttgart (Germany)

    2015-01-19

    In this study the key factors in the creation and coalescence of strain localization regions in dual-phase steels were investigated. An in-situ tensile setup was used to follow the microscopic deformation of ferrite phase inside the microstructure of DP600 steel. The test was continued until the specimen was very close to final failure. The captured scanning electron microscopy (SEM) micrographs enabled us to directly observe the evolution of deformation bands as a contour of strain distribution in the ferrite matrix. The image processing method was used to quantify the ferrite microscopic strains; the obtained strain maps were superimposed onto the SEM micrographs. The results revealed important deformational characteristics of the microstructure at the microscopic level. It was observed that despite the formation of slip bands inside the large grains during the early stages of deformation, the large ferrite grains did not contribute to the formation of high-strain bands until the final stages of severe necking. The behavior of voids and initial defects inside the localization bands was also studied. In the final stages of deformation, cracks were observed to preferentially propagate in the direction of local deformation bands and to coalescence with each other to form the final failure lines in the microstructure. It was observed that in the final stages of deformation, the defects or voids outside the deformation bands do not contribute to the final failure mechanisms and could be considered to be of minor importance.

  18. Fatigue crack propagation behavior and debris formation in Ti-6Al-4V alloys with different grain size

    Science.gov (United States)

    Kim, H. J.; Nakahigashi, J.; Ebara, R.; Endo, M.

    2017-05-01

    Titanium alloy is widely used in applications where high specific strength as well as good heat and corrosion resistance is required. Consequently, there are a number of studies on the fatigue characteristics of titanium alloys. In recent years, grain refinement for metallic materials processed by several methods, such as severe plastic deformation, has been studied to improve the mechanical properties. Grain refinement of titanium alloy by the protium treatment is a new technology, and the fatigue properties of this material have yet to be sufficiently studied. Therefore in this study, tension-compression fatigue tests were conducted for a protium treated Ti-6Al-4V alloy with ultra-fine grains of 0.5 μm in average size as well as for an untreated alloy with conventional grains of 6 μm. Specimens had shallow, sharp notches with the depth of 50 μm and the root radius of 10 μm, which enabled successive observation of the initiation and early propagation behaviors of small fatigue cracks. Substantial amount of oxide debris was formed along the crack during crack propagation. The role of debris was discussed in association with propagation resistance.

  19. Microstructural characterization, formation mechanism and fracture behavior of the needle δ phase in Fe–Ni–Cr type superalloys with high Nb content

    Energy Technology Data Exchange (ETDEWEB)

    Ning, Yongquan, E-mail: luckyning@nwpu.edu.cn [School of Materials Science & Engineering, Northwestern Polytechnical University, Xi' an 710072 (China); Huang, Shibo [Anshan Iron & Steel Group Corporation Bayuquan Subsidiary Company, Bayuquan 115007 (China); Fu, M.W. [Department of Mechanical Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China); Dong, Jie [Inspection & Research Institute of Boiler & Pressure Vessel of Jiangxi Province, Nanchang 330029 (China)

    2015-11-15

    Microstructural characterization, formation mechanism and fracture behavior of the needle δ phase in Fe–Ni–Cr type superalloys with high Nb content (GH4169, equivalent to Inconel 718) have been quantitatively investigated in this research. The typical microstructures of δ phases with the stick, mixed and needle shapes obviously present in Inconel 718 after the isothermal upsetting at the temperature of 980–1060 °C with the initial strain rate of 10{sup −3}–10{sup −1} s{sup −1}. It is found that the shape of the δ phase has a great effect on the mechanical properties of the alloy, viz., the stick δ phase behaves good plasticity and the needle δ phase has good strength. In addition, the needle δ phase can be used to control the grain size as it can prevent grain growth. The combined effect of the localized necking and microvoid coalescence leads to the final ductile fracture of the GH4169 components with the needle δ phase. Both dislocation motion and atom diffusion are the root-cause for the needle δ phase to be firstly separated at grain boundary and then at sub-boundary. The formation mechanism of the needle δ phase is the new finding in this research. Furthermore, it is the primary mechanism for controlling the needle δ phase in Fe–Ni–Cr type superalloys with high Nb content. - Highlights: • Shape of the δ phase takes great effect on mechanical property. • Needle δ phase plays a great role to prevent grain growth. • Needle δ phase can enhance the fracture strength. • Microstructure mechanism of the needle δ phase has been investigated. • Fracture behavior of the needle δ phase has been studied.

  20. Voiding school as a treatment of daytime incontinence or enuresis: Children's experiences of the intervention.

    Science.gov (United States)

    Saarikoski, A; Koppeli, R; Salanterä, S; Taskinen, S; Axelin, A

    2017-09-23

    Daytime incontinence and enuresis are common problems in otherwise healthy children, and negatively influence their social lives and self-esteem. Motivation for treatment is often a real clinical problem. Children's experiences of their incontinence treatments have not been previously described. The aim of this study was to describe children's experiences of the Voiding School intervention as a treatment for their incontinence. A qualitative, descriptive focus-group study with a purposive sample was conducted at a Finish university hospital in 2014. Children aged 6-12 years participated in the Voiding School at an outpatient clinic. The intervention included two 1-day group visits 2 months apart. The educational content was based on the International Children Continence Society's standards for urotherapy. The education was delivered with child-oriented teaching methods. At the end of the second visit, 19 children were interviewed in five groups. Data were analysed with inductive content analysis. The children described incontinence as an embarrassing problem, which they had to hide at any cost. They had experienced bullying and social isolation because of it. Normal outpatient visits emphasized adult-to-adult communication, which made the children feel like outsiders. The children perceived the Voiding School as a nice and child-oriented experience. Making new friends was especially important to younger boys who felt that the Voiding School day was too long and issue-oriented. In the Voiding School, videos and 'learning by doing' helped the children to understand the basis of given advice, and they were able to learn new habits, which gave them control over the incontinence; this helped them to become 'the boss of the bladder'. Sharing experiences and improvements in their incontinence with their peers supported the children's self-esteem and encouraged them to do new things, such as staying overnight with friends. These experiences helped them to acquire control

  1. Time-of-flight MR angiography of carotid artery stenosis: does a flow void represent severe stenosis?

    NARCIS (Netherlands)

    Nederkoorn, Paul J.; van der Graaf, Yolanda; Eikelboom, Bert C.; van der Lugt, Aad; Bartels, Lambertus W.; Mali, Willem P. T. M.

    2002-01-01

    BACKGROUND AND PURPOSE: Time-of-flight (TOF) magnetic resonance angiography (MRA) is commonly used to visualize the carotid arteries; however, flow void artifacts can appear. Our purpose was to determine the frequency and diagnostic meaning of flow voids by using real patient data, as part of a

  2. Evaluation of urologic morbidity after radiotherapy for cervical carcinoma by urodynamic examinations and patient voiding schemes: a prospective study

    DEFF Research Database (Denmark)

    Lajer, Henrik; Thranov, Ingrid R; Bagi, Per

    2002-01-01

    To assess urologic morbidity in a 5-year period by urodynamic examinations and patient voiding schemes after radiotherapy and brachytherapy for cervical carcinoma.......To assess urologic morbidity in a 5-year period by urodynamic examinations and patient voiding schemes after radiotherapy and brachytherapy for cervical carcinoma....

  3. A comparative study of voiding in rat and guinea pig: simultaneous measurement of flow rate and pressure

    NARCIS (Netherlands)

    E. van Asselt (Els); J.M. Groen (Jan); R. van Mastrigt (Ron)

    1995-01-01

    textabstractIn this study, the voiding phase of the micturition cycle in the anesthetized rat and guinea pig is analyzed. In both animals, voiding is characterized by an increase in intravesical pressure and then a decrease, which is accompanied by flow through the urethra and emission of urine. An

  4. The relevance of urodynamic studies for Urge syndrome and dysfunctional voiding: a multicenter controlled trial in children.

    Science.gov (United States)

    Bael, An; Lax, Hildegard; de Jong, Tom P V M; Hoebeke, Piet; Nijman, Rien J M; Sixt, Rune; Verhulst, John; Hirche, Herbert; van Gool, Jan D

    2008-10-01

    The objective of this study was to compare prospectively, in urge syndrome and dysfunctional voiding, clinical patterns with urodynamic patterns, to assess changes in urodynamic patterns after treatment, and to correlate urodynamic patterns and parameters with treatment outcome. In the European Bladder Dysfunction Study 97 children with clinically diagnosed urge syndrome received standard treatment, to which was randomly added placebo, oxybutynin or bladder training with online feedback. In a separate branch 105 children with clinically diagnosed dysfunctional voiding were randomly allocated to standard treatment or standard treatment plus pelvic floor training with online feedback. In all children urodynamic studies were performed before and immediately after treatment. In urge syndrome detrusor overactivity was present in 33% of cases before and 27% after treatment (of which 65% were de novo). Detrusor overactivity did not correlate with treatment outcome. In dysfunctional voiding increased pelvic floor activity during voiding, which was present in 67% of cases before and 56% after treatment (of which 45% were de novo), did not correlate with treatment outcome. In urge syndrome as well as in dysfunctional voiding neither maximum detrusor pressure during voiding, cystometric bladder capacity, bladder compliance nor free flow patterns correlated with treatment outcome. Neither detrusor overactivity nor increased pelvic floor activity during voiding correlated with treatment outcome. Standard treatment could be the first choice in urge syndrome as well as in dysfunctional voiding, reserving urodynamic studies for patients in whom this first approach fails.

  5. Negative Poisson's Ratio Behavior Induced by an Elastic Instability

    NARCIS (Netherlands)

    Bertoldi, Katia; Reis, Pedro M.; Willshaw, Stephen; Mullin, Tom

    2009-01-01

    Negative Poisson's ratio behavior has been uncovered in cellular solids that comprise a solid matrix with a square array of circular voids. The simplicity of the fabrication implies robust behavior, which is relevant over a range of scales. The behavior results from an elastic instability, which

  6. Void fraction in horizontal bulk flow boiling at high flow qualities

    Energy Technology Data Exchange (ETDEWEB)

    Collado, Fancisco J.; Monne, Carlos [Dpto. de Ingenieria Mecanica, Universidad de Zaragoza-CPS, Maria de Luna 3, 50018-Zaragoza (Spain); Pascau, Antonio [Dpto. de Ciencia de los Materiales y Fluidos, Universidad de Zaragoza-CPS, Maria de Luna 3, 50018-Zaragoza (Spain)

    2008-04-15

    In this work, a new thermodynamic prediction of the vapor void fraction in bulk flow boiling, which is the core process of many energy conversion systems, is analyzed. The current heat balance is based on the flow quality, which is closely related to the measured void fraction, although some correlation for the vapor-liquid velocity ratio is needed. So here, it is suggested to work with the 'static' or thermodynamic quality, which is directly connected to the void fraction through the densities of the phases. Thus, the relation between heat and the mixture enthalpy (here based on the thermodynamic quality instead of the flow one) should be analyzed in depth. The careful void fraction data taken by Thom during the 'Cambridge project' for horizontal saturated flow boiling with high flow qualities ({<=}0.8) have been used for this analysis. As main results, first, we have found that the applied heat and the increment of the proposed thermodynamic enthalpy mixture throughout the heated duct do not agree, and for closure, a parameter is needed. Second, it has been checked that this parameter is practically equal to the classic velocity ratio or 'slip' ratio, suggesting that it should be included in a true thermodynamic heat balance. Furthermore, it has been clearly possible to improve the 'Cambridge project' correlations for the 'slip' ratio, here based on inlet pressure and water velocity, and heat flux. The calculated void fractions compare quite well with the measured ones. Finally, the equivalence of the suggested new heat balance with the current one through the 'slip' ratio is addressed. Highlighted is the same new energetic relation for saturated flow boiling that has been recently confirmed by the authors for Knights data, also taken during the 'Cambridge project', which include not only horizontal but also vertical upwards flows with moderate outlet flow quality ({<=}0.2). (author)

  7. Characterization of voids in shock-loaded Al single crystal by combining X-ray tomography and electron microscopy

    Science.gov (United States)

    Hong, Chuanshi; Fæster, Søren; Hansen, Niels; Huang, Xiaoxu; Barabash, Rozaliya I.

    2017-07-01

    A combination of X-ray tomography and electron backscatter diffraction (EBSD) was applied to investigate both the shape of voids and the plastic deformation around voids in an Al single crystal shock-loaded in the direction. The combination of these two techniques allows the addition of crystallographic information to X-ray tomography and allows the addition of three-dimensional information to EBSD data. It is found that the voids are octahedral with {1 1 1} faces and that regular patterns of lattice reorientation exist around individual voids. The results provide new insights to the process of void growth during shock loading, which is important for both civil and military applications.

  8. Effect of the Thermodynamic Behavior of Selective Laser Melting on the Formation of In situ Oxide Dispersion-Strengthened Aluminum-Based Composites

    Directory of Open Access Journals (Sweden)

    Lianfeng Wang

    2016-11-01

    Full Text Available This paper presents a comprehensive investigation of the phase and microstructure, the thermodynamic behavior within the molten pool, and the growth mechanism of in situ oxide dispersion-strengthened (ODS aluminum-based composites processed by a selective laser melting (SLM additive manufacturing/3D printing process. The phase and microstructure were characterized by X-ray diffraction (XRD and a scanning electronic microscope (SEM equipped with EDX, respectively. The thermodynamic behavior within the molten pool was investigated for a comprehensive understanding on the growth mechanism of the SLM-processed composite using a finite volume method (FVM. The results revealed that the in situ Al2Si4O10 ODS Al-based composites were successfully fabricated by SLM. Combined with the XRD spectrum and EDX analysis, the new silica-rich Al2Si4O10 reinforcing phase was identified, which was dispersed around the grain boundaries of the aluminum matrix under a reasonable laser power of 200 W. Combined with the activity of Marangoni convection and repulsion forces, the characteristic microstructure of SLM-processed Al2Si4O10 ODS Al-based composites tended to transfer from the irregular network structure to the nearly sphere-like network structure in regular form by increasing the laser power. The formation mechanism of the microstructure of SLM-processed Al2Si4O10 ODS Al-based composites is thoroughly discussed herein.

  9. The roles of identity formation and moral identity in college student mental health, health-risk behaviors, and psychological well-being.

    Science.gov (United States)

    Hardy, Sam A; Francis, Stephen W; Zamboanga, Byron L; Kim, Su Yeong; Anderson, Spencer G; Forthun, Larry F

    2013-04-01

    This study examined the roles of identity formation and moral identity in predicting college student mental health (anxiety and depressive symptoms), health-risk behaviors (hazardous alcohol use and sexual risk taking), and psychological well-being (self-esteem and meaning). The sample comprised 9,500 college students (aged 18-25 years, mean = 19.78, standard deviation = 1.61; 73% female; 62% European American), from 31 different universities, who completed an online self-report survey. Structural equation models found that identity maturity (commitment making and identity synthesis) predicted 5 of the health outcomes (except sexual risk taking), and moral identity predicted all of the health outcomes. In most cases identity maturity and moral identity also interacted in predicting mental health and psychological well-being, but not health-risk behaviors. The maturity and specific contents of identity may both play unique and often interactive roles in predicting college student health. Thus, college student health might be bolstered by helping them establish appropriate identity commitments. © 2012 Wiley Periodicals, Inc.

  10. Larger voids in mechanically stable, loose packings of 1.3μm frictional, cohesive particles: Their reconstruction, statistical analysis, and impact on separation efficiency.

    Science.gov (United States)

    Reising, Arved E; Godinho, Justin M; Hormann, Kristof; Jorgenson, James W; Tallarek, Ulrich

    2016-03-04

    Lateral transcolumn heterogeneities and the presence of larger voids in a packing (comparable to the particle size) can limit the preparation of efficient chromatographic columns. Optimizing and understanding the packing process provides keys to better packing structures and column performance. Here, we investigate the slurry-packing process for a set of capillary columns packed with C18-modified, 1.3μm bridged-ethyl hybrid porous silica particles. The slurry concentration used for packing 75μm i.d. fused-silica capillaries was increased gradually from 5 to 50mg/mL. An intermediate concentration (20mg/mL) resulted in the best separation efficiency. Three capillaries from the set representing low, intermediate, and high slurry concentrations were further used for three-dimensional bed reconstruction by confocal laser scanning microscopy and morphological analysis of the bed structure. Previous studies suggest increased slurry concentrations will result in higher column efficiency due to the suppression of transcolumn bed heterogeneities, but only up to a critical concentration. Too concentrated slurries favour the formation of larger packing voids (reaching the size of the average particle diameter). Especially large voids, which can accommodate particles from>90% of the particle size distribution, are responsible for a decrease in column efficiency at high slurry concentrations. Our work illuminates the increasing difficulty of achieving high bed densities with small, frictional, cohesive particles. As particle size decreases interparticle forces become increasingly important and hinder the ease of particle sliding during column packing. While an optimal slurry concentration is identified with respect to bed morphology and separation efficiency under conditions in this work, our results suggest adjustments of this concentration are required with regard to particle size, surface roughness, column dimensions, slurry liquid, and external effects utilized during the

  11. Encapsulating Metal Clusters and Acid Sites within Small Voids: Synthetic Strategies and Catalytic Consequences

    Science.gov (United States)

    Goel, Sarika

    active sites. We have demonstrated the selectivity of the encapsulation processes by combining transmission electron microscopy and chemisorptive titrations with rigorous catalytic assessments of the ability of these materials to catalyze reactions of small molecules, which can access the intracrystalline voids, but not of larger molecules that cannot access the metal clusters within such voids. The selective confinement of clusters also prevented their contact with sulfur compounds (e.g., thiophene and H2S), thus allowing reactions to occur at conditions that otherwise render unconfined clusters unreactive. We have also developed synthetic protocols and guiding principles, inspired by mechanistic considerations, for the synthesis of zeolites via interzeolite transformations without the use of organic structure-directing agents (OSDA). More specifically, we have synthesized high-silica MFI (ZSM-5), CHA (chabazite), STF (SSZ-35) and MTW (ZSM-12) zeolites from FAU (faujasite) or BEA (beta) parent materials. Structures with lower framework densities (FAU or BEA) were successfully transformed into thermodynamically-favored, more stable structures with higher framework densities (MFI, CHA, STF, and MTW); to date, target materials with higher Si/Al ratios (Si/Al >10) have not been synthesized via interzeolite transformations without the aid of the OSDA species used to discover these zeolite structures and deemed essential up until now for their successful synthesis. Overcoming kinetic hurdles in such transformations required either the presence of common composite building units (CBU) between parent and target structures or, in their absence, the introduction of small amount of seeds of the daughter structures. The NaOH/SiO2 ratio, H2O/SiO2 ratio and Al content in reagents are used to enforce synchronization between the swelling and local restructuring within parent zeolite domains with the spalling of fragments or building units from seeds of the target structure. The

  12. UGC 3672: an unusual merging triplet of gas-rich galaxies in the Lynx-Cancer void

    Science.gov (United States)

    Chengalur, J. N.; Pustilnik, S. A.; Egorova, E. S.

    2017-02-01

    We present H I 21 cm and optical observations of UGC 3672 which is located near the centre of the nearby Lynx-Cancer void. We find that UGC 3672 consists of an approximately linearly aligned triplet of gas-rich dwarfs with large-scale velocity continuity along the triplet axis. The faintest component of the triplet is extremely gas-rich M_{H I}/L_B ˜ 17) and also extremely metal deficient (12 + log (O/H) ˜ 7.0). The metallicity of this dwarf is close to the 'floor' observed in star-forming galaxies. Low-resolution H I images show that the galaxy triplet is located inside a common H I envelope, with fairly regular, disc-like kinematics. At high angular resolution however, the gas is found to be confined to several filamentary tidal tails and bridges. The linear alignment of the galaxies, along with the velocity continuity that we observe, is consistent with the galaxies lying along a filament. We argue that the location of this highly unusual system in an extremely low-density environment is not a coincidence, but is a consequence of structure formation proceeding more slowly and also probing smaller scales than in regions with average density. Our observations also indicate that wet mergers of galaxies flowing along filaments is a possible pathway for the formation of gas-rich discs. The UGC 3672 system provides an interesting opportunity to study the kind of interactions typical between high-redshift extremely gas-rich unevolved small systems that lie at base of the hierarchical galaxy formation model.

  13. A Tremella-Like Nanostructure of Silicon@void@graphene-Like Nanosheets Composite as an Anode for Lithium-Ion Batteries

    National Research Council Canada - National Science Library

    Hongwei Mi; Fang Li; Shuxian Xu; Ziang Li; Xiaoyan Chai; Chuanxin He; Yongliang Li; Jianhong Liu

    2016-01-01

    .... In this work, a tremella-like nanostructure of silicon@void@graphene-like nanosheets (Si@void@G) composite was successfully synthesized and employed as a high-performance anode material with high capacity, cycling stability, and rate capacity...

  14. A New Void Fraction Measurement Method for Gas-Liquid Two-Phase Flow in Small Channels

    Directory of Open Access Journals (Sweden)

    Huajun Li

    2016-01-01

    Full Text Available Based on a laser diode, a 12 × 6 photodiode array sensor, and machine learning techniques, a new void fraction measurement method for gas-liquid two-phase flow in small channels is proposed. To overcome the influence of flow pattern on the void fraction measurement, the flow pattern of the two-phase flow is firstly identified by Fisher Discriminant Analysis (FDA. Then, according to the identification result, a relevant void fraction measurement model which is developed by Support Vector Machine (SVM is selected to implement the void fraction measurement. A void fraction measurement system for the two-phase flow is developed and experiments are carried out in four different small channels. Four typical flow patterns (including bubble flow, slug flow, stratified flow and annular flow are investigated. The experimental results show that the development of the measurement system is successful. The proposed void fraction measurement method is effective and the void fraction measurement accuracy is satisfactory. Compared with the conventional laser measurement systems using standard laser sources, the developed measurement system has the advantages of low cost and simple structure. Compared with the conventional void fraction measurement methods, the proposed method overcomes the influence of flow pattern on the void fraction measurement. This work also provides a good example of using low-cost laser diode as a competent replacement of the expensive standard laser source and hence implementing the parameter measurement of gas-liquid two-phase flow. The research results can be a useful reference for other researchers’ works.

  15. Cytological features of carcinoma of the collecting ducts of Bellini in voided urine cytology.

    Science.gov (United States)

    Ohsaki, Hiroyuki; Hirakawa, Eiichiro; Kushida, Yoshio; Kadota, Kyuichi; Ishikawa, Masashi; Haba, Reiji

    2009-09-01

    Carcinoma of the collecting ducts of Bellini (CCDB) is a rare histological type of renal cell carcinoma. This article describes the cytological features of CCDB in voided urine, confirmed on the basis of the histopathology and immunohistochemistry. The CCDB cells occurred singly in loose aggregates and in small clusters, occasionally in a rosette-like structure. There were various types of cancer cells, including round to oval, spindle, and tadpole-like cells. The nuclei usually showed coarse chromatin, inconspicuous nucleoli, and lacy to vacuolated cytoplasm. CCDB of the kidney is a rare cytodiagnostic challenge in voided urine cytology alone. When the cytological diagnosis is considered, it is necessary to perform immunocytochemistry and correlate the clinical history and imaging studies. 2009 Wiley-Liss, Inc.

  16. Sacral Herpes Zoster Associated with Voiding Dysfunction in a Young Patient with Scrub Typhus

    Science.gov (United States)

    2015-01-01

    When a patient presents with acute voiding dysfunction without a typical skin rash, it may be difficult to make a diagnosis of herpes zoster. Here, we present a case of scrub typhus in a 25-year-old man with the complication of urinary dysfunction. The patient complained of loss of urinary voiding sensation and constipation. After eight days, he had typical herpes zoster eruptions on the sacral dermatomes and hypalgesia of the S1-S5 dermatomes. No cases of dual infection with varicella zoster virus and Orientia tsutsugamushi were found in the literature. In the described case, scrub typhus probably induced sufficient stress to reactivate the varicella zoster virus. Early recognition of this problem is imperative for prompt and appropriate management, as misdiagnosis can lead to long-term urinary dysfunction. It is important that a diagnosis of herpes zoster be considered, especially in patients with sudden onset urinary retention. PMID:26157595

  17. Strain gradient crystal plasticity analysis of a single crystal containing a cylindrical void

    DEFF Research Database (Denmark)

    Borg, Ulrik; Kysar, J.W.

    2007-01-01

    to one another. Finite element simulations are performed using a strain gradient crystal plasticity formulation with an intrinsic length scale parameter in a non-local strain gradient constitutive framework. For a vanishing length scale parameter the non-local formulation reduces to a local crystal...... plasticity formulation. The stress and deformation fields obtained with a local non-hardening constitutive formulation are compared to those obtained from a local hardening formulation and to those from a non-local formulation. Compared to the case of the non-hardening local constitutive formulation......, it is shown that a local theory with hardening has only minor effects on the deformation field around the void, whereas a significant difference is obtained with the non-local constitutive relation. Finally, it is shown that the applied stress state required to activate plastic deformation at the void is up...

  18. Cooperative Position Aware Mobility Pattern of AUVs for Avoiding Void Zones in Underwater WSNs

    Directory of Open Access Journals (Sweden)

    Nadeem Javaid

    2017-03-01

    Full Text Available In this paper, we propose two schemes; position-aware mobility pattern (PAMP and cooperative PAMP (Co PAMP. The first one is an optimization scheme that avoids void hole occurrence and minimizes the uncertainty in the position estimation of glider’s. The second one is a cooperative routing scheme that reduces the packet drop ratio by using the relay cooperation. Both techniques use gliders that stay at sojourn positions for a predefined time, at sojourn position self-confidence (s-confidence and neighbor-confidence (n-confidence regions that are estimated for balanced energy consumption. The transmission power of a glider is adjusted according to those confidence regions. Simulation results show that our proposed schemes outperform the compared existing one in terms of packet delivery ratio, void zones and energy consumption.

  19. Cooperative Position Aware Mobility Pattern of AUVs for Avoiding Void Zones in Underwater WSNs.

    Science.gov (United States)

    Javaid, Nadeem; Ejaz, Mudassir; Abdul, Wadood; Alamri, Atif; Almogren, Ahmad; Niaz, Iftikhar Azim; Guizani, Nadra

    2017-03-13

    In this paper, we propose two schemes; position-aware mobility pattern (PAMP) and cooperative PAMP (Co PAMP). The first one is an optimization scheme that avoids void hole occurrence and minimizes the uncertainty in the position estimation of glider's. The second one is a cooperative routing scheme that reduces the packet drop ratio by using the relay cooperation. Both techniques use gliders that stay at sojourn positions for a predefined time, at sojourn position self-confidence (s-confidence) and neighbor-confidence (n-confidence) regions that are estimated for balanced energy consumption. The transmission power of a glider is adjusted according to those confidence regions. Simulation results show that our proposed schemes outperform the compared existing one in terms of packet delivery ratio, void zones and energy consumption.

  20. Voiding patterns and prevalence of incontinence in women. A questionnaire survey

    DEFF Research Database (Denmark)

    Sommer, P; Bauer, T; Nielsen, K K

    1990-01-01

    A detailed questionnaire on the occurrence of irritative and obstructive voiding symptoms, incontinence and the number of childbirths was sent out to 600 women aged between 20 and 79 years, randomly selected from the National Register; 432 (72%) returned the questionnaire and 414 (69%) were...... with age; 54 (13.6%) voided at least twice per night. About 40% complained of incontinence but this was troublesome in only 6%; 15.3, 13.3 and 11.5% had stress, urge and mixed incontinence respectively. More than 8% wore nappies or sanitary towels every day to protect against urinary leakage. Although...... the tendency to wear nappies or sanitary towels increased with age, the increase was not statistically significant. There was a positive correlation between the occurrence of stress incontinence and childbirth in the group as a whole....

  1. Annular nanoplasmonic void arrays as tunable surface enhanced Raman spectroscopy substrates

    Science.gov (United States)

    Li, Zhibo; Clark, Alasdair W.; Cooper, Jonathan M.

    2014-07-01

    We report the use of annular nano-voids in a metallic thin-film as programmable molecular sensors for surface-enhanced Raman spectroscopy (SERS). To date, research into these structures has focused on the exploration of their extraordinary optical transmission attributes. We now show that by using advanced lithography and simulation tools, we can generate a porous SERS material for molecular interrogation. Using ultra-thin annular structures, rather than simple circular holes, allows us to reduce both the volume and cross-sectional area of the void, maximizing the electric-field confinement, while, importantly for SERS, producing resonant conditions in the visible region of the spectrum. By comparing our annular films with conventional circular films with the same resonant frequency, we show a significant improvement in the efficiency of Raman scatter, creating stronger signals that also contain more spectral information.

  2. An axially multilayered low void worth liquid-metal fast breeder reactor core concept

    Energy Technology Data Exchange (ETDEWEB)

    Kamei, T.; Yamaoka, M. (Toshiba Corp., Nuclear Engineering Lab., 4-1 Ukishima-cho, Kawasaki-ku, Kawasaki-shi 210 (JP))

    1992-03-01

    A new core concept with a negative sodium void reactivity coefficient has evolved. The core is composed of two core layers in the axial direction. The core layers are separated by an internal blanket, the central region of which comprises a neutron-absorbing material such as boron carbide or tantalum. Consequently, the two core layers are completely decoupled as regards neutronics, leading to an effective increase in neutron leakage from the core region when sodium is voided. This design is expected to be free from the disadvantages of a large core radius, as seen in a conventional spoiled core such as a pancake core. In this paper the design is described in detail, and its application to a 300-MW (electronic) metal fuel core and to a 450-MW (electric) minor actinide burned core is given as an example.

  3. Effects of an Internet-based cognitive behavioral therapy (iCBT) program in Manga format on improving subthreshold depressive symptoms among healthy workers: a randomized controlled trial.

    Science.gov (United States)

    Imamura, Kotaro; Kawakami, Norito; Furukawa, Toshi A; Matsuyama, Yutaka; Shimazu, Akihito; Umanodan, Rino; Kawakami, Sonoko; Kasai, Kiyoto

    2014-01-01

    The purpose of this study was to develop a new Internet-based computerized cognitive behavior therapy (iCBT) program in Manga format, the Japanese cartoon, for workers and to examine the effects of the iCBT program on improving subthreshold depression using a randomized controlled trial (RCT) design among workers employed in private companies in Japan. All workers in a company (n = 290) and all workers in three departments (n = 1,500) at the headquarters of another large company were recruited by an invitation e-mail. Participants who fulfilled the inclusion criteria were randomly allocated to intervention or control groups (N = 381 for each group). A six-week, six-lesson iCBT program using Manga (Japanese comic) story was developed. The program included several CBT skills: self-monitoring, cognitive restructuring, assertiveness, problem solving, and relaxation. The intervention group studied the iCBT program at a frequency of one lesson per week. Depression (Beck Depression Inventory II; BDI-II) was assessed as a primary outcome at baseline, and three- and six-month follow-ups for both intervention and control groups were performed. The iCBT program showed a significant intervention effect on BDI-II (t = -1.99, p<0.05) with small effect sizes (Cohen's d: -0.16, 95% Confidence Interval: -0.32 to 0.00, at six-month follow-up). The present study first demonstrated that a computerized cognitive behavior therapy delivered via the Internet was effective in improving depression in the general working population. It seems critical to improve program involvement of participants in order to enhance the effect size of an iCBT program. UMIN Clinical Trials Registry UMIN000006210.

  4. Effects of an Internet-based cognitive behavioral therapy (iCBT program in Manga format on improving subthreshold depressive symptoms among healthy workers: a randomized controlled trial.

    Directory of Open Access Journals (Sweden)

    Kotaro Imamura

    Full Text Available OBJECTIVE: The purpose of this study was to develop a new Internet-based computerized cognitive behavior therapy (iCBT program in Manga format, the Japanese cartoon, for workers and to examine the effects of the iCBT program on improving subthreshold depression using a randomized controlled trial (RCT design among workers employed in private companies in Japan. METHOD: All workers in a company (n = 290 and all workers in three departments (n = 1,500 at the headquarters of another large company were recruited by an invitation e-mail. Participants who fulfilled the inclusion criteria were randomly allocated to intervention or control groups (N = 381 for each group. A six-week, six-lesson iCBT program using Manga (Japanese comic story was developed. The program included several CBT skills: self-monitoring, cognitive restructuring, assertiveness, problem solving, and relaxation. The intervention group studied the iCBT program at a frequency of one lesson per week. Depression (Beck Depression Inventory II; BDI-II was assessed as a primary outcome at baseline, and three- and six-month follow-ups for both intervention and control groups were performed. RESULTS: The iCBT program showed a significant intervention effect on BDI-II (t = -1.99, p<0.05 with small effect sizes (Cohen's d: -0.16, 95% Confidence Interval: -0.32 to 0.00, at six-month follow-up. CONCLUSIONS: The present study first demonstrated that a computerized cognitive behavior therapy delivered via the Internet was effective in improving depression in the general working population. It seems critical to improve program involvement of participants in order to enhance the effect size of an iCBT program. TRIAL REGISTRATION: UMIN Clinical Trials Registry UMIN000006210.

  5. Heat transfer enhancement for spent nuclear fuel assembly disposal packages using metallic void fillers: A prevention technique for solidification shrinkage-induced interfacial gaps

    Science.gov (United States)

    Park, Yongsoo; McKrell, Thomas J.; Driscoll, Michael J.

    2017-06-01

    This study considers replacing the externally accessible void spaces inside a disposal package containing a spent nuclear fuel assembly (SNFA) with high heat conducting metal to increase the effective thermal conductivity of the package and simplify the heat transfer mechanism inside the package by reducing it to a conduction dominant problem. The focus of the study is on preventing the gaps adjacent to the walls of the package components, produced by solidification shrinkage of poured liquid metal. We approached the problem by providing a temporary coating layer on the components to avoid direct build-up of thick metal oxides on their surface to promote metallic bonding at the interfaces under a non-inert environment. Laboratory scale experiments without SNFA were performed with Zn coated low carbon steel canisters and Zamak-3 void filler under two different filling temperature conditions - below and above the melting point of Zn (designated BMP and AMP respectively). Gap formation was successfully prevented in both cases while we confirmed an open gap in a control experiment, which used an uncoated canister. Minor growth of Al-Fe intermetallic phases was observed at the canister/filler interface of the sample produced under the BMP condition while their growth was significant and showed irregularly distributed morphology in the sample produced under the AMP condition, which has a potential to mitigate excessive residual stresses caused by shrinkage prevention. A procedure for the full-scale application was specified based on the results.

  6. Impact of benign prostatic hyperplasia surgical treatment on voiding and urinary bladder filling symptoms

    Directory of Open Access Journals (Sweden)

    Milićević Snježana

    2010-01-01

    Full Text Available Background/Aim. Benign prostatic hyperplasia (BHP is one of the most common diseases of elderly men. The aim of this study was to evaluate the effect of surgical treatment of benign prostatic hyperplasia to voiding and urinary bladder filling symptoms. Quantification of voiding and filling symptoms was done with the International Prostate Symptom Score (IPSS. Method. The study included 80 patients with BHP, of whom 40 were treated with open prostatectomy (group A, and other 40 with transurethral resection of prostate gland (group B. All the patients were under 80 years old (average age in the group A was 70.23 years with a variation interval of 21 years, and in the group B 69.37 years with a variation interval of 22 years, with a value of IPSS > 19 points, quantity of residual urine higher than 150 mL, the weight of benign prostatic gland hyperplasia tissue over 30 grams for the method of prostate transurethral resection, and over 80 grams for the method of open prostatectomy. To all patients, for two times, the value of IPSS was determined, and then in a postoperative period in time intervals of 4 and 12 weeks. Results. Arithmetic mean of IPSS preoperatively was 32.05 points in the group A and 31.75 points in the group B. During the postoperative check-ups in time intervals of 4 and 12 weeks, arithmetic means of IPSS in the group A were 5.4 and 1.85 points, respectively, and in the group B 11.425 and 9.025 points, respectively. Surgical treatment had better effect on voiding symptoms than on urinary bladder filling ones. Conclusion. After the mentioned surgical procedures a significant reduction of the lower urinary tract symptoms quantified by the IPSS was observed. Surgical treatment of BHP had a more pronounced effect on the voiding symptoms in relation to filling ones.

  7. Effects of voids on thermal-mechanical reliability of lead-free solder joints

    Directory of Open Access Journals (Sweden)

    Benabou Lahouari

    2014-06-01

    Full Text Available Reliability of electronic packages has become a major issue, particularly in systems used in electrical or hybrid cars where severe operating conditions must be met. Many studies have shown that solder interconnects are critical elements since many failure mechanisms originate from their typical response under thermal cycles. In this study, effects of voids in solder interconnects on the electronic assembly lifetime are estimated based on finite element simulations.

  8. Tritium containing polymers having a polymer backbone substantially void of tritium

    Science.gov (United States)

    Jensen, George A.; Nelson, David A.; Molton, Peter M.

    1992-01-01

    A radioluminescent light source comprises a solid mixture of a phosphorescent substance and a tritiated polymer. The solid mixture forms a solid mass having length, width, and thickness dimensions, and is capable of self-support. In one aspect of the invention, the phosphorescent substance comprises solid phosphor particles supported or surrounded within a solid matrix by a tritium containing polymer. The tritium containing polymer comprises a polymer backbone which is essentially void of tritium.

  9. Feasibility Study of In-situ Characterization of Size Distribution of Air Voids in Concrete Pavements

    OpenAIRE

    Li, Kai Ming; Tong, Bao N; Liu, Sheng

    2013-01-01

    This report concerns a feasibility study on the use of a non-destructive and non-invasive method to determine the size distribution of air voids in fresh concrete, which will be used for laying concrete pavement. A preliminary review of different techniques suggested that the measurement of the p-wave velocity of ultrasound pulses transmitted through a fresh concrete specimen offers the most straightforward approach. This report describes an experimental study to address the design of an expe...

  10. Centimeter to decimeter hollow concretions and voids in Gale Crater sediments, Mars

    Science.gov (United States)

    Wiens, Roger C.; Rubin, David M.; Goetz, Walter; Fairén, Alberto G.; Schwenzer, Susanne P.; Johnson, Jeffrey R.; Milliken, Ralph; Clark, Ben; Mangold, Nicolas; Stack, Kathryn M.; Oehler, Dorothy; Rowland, Scott; Chan, Marjorie; Vaniman, David; Maurice, Sylvestre; Gasnault, Olivier; Rapin, William; Schroeder, Susanne; Clegg, Sam; Forni, Olivier; Blaney, Diana; Cousin, Agnes; Payré, Valerie; Fabre, Cecile; Nachon, Marion; Le Mouelic, Stephane; Sautter, Violaine; Johnstone, Stephen; Calef, Fred; Vasavada, Ashwin R.; Grotzinger, John P.

    2017-06-01

    Voids and hollow spheroids between ∼1 and 23 cm in diameter occur at several locations along the traverse of the Curiosity rover in Gale crater, Mars. These hollow spherical features are significantly different from anything observed in previous landed missions. The voids appear in dark-toned, rough-textured outcrops, most notably at Point Lake (sols 302-305) and Twin Cairns Island (sol 343). Point Lake displays both voids and cemented spheroids in close proximity; other locations show one or the other form. The spheroids have 1-4 mm thick walls and appear relatively dark-toned in all cases, some with a reddish hue. Only one hollow spheroid (Winnipesaukee, sol 653) was analyzed for composition, appearing mafic (Fe-rich), in contrast to the relatively felsic host rock. The interior surface of the spheroid appears to have a similar composition to the exterior with the possible exceptions of being more hydrated and slightly depleted in Fe and K. Origins of the spheroids as Martian tektites or volcanic bombs appear unlikely due to their hollow and relatively fragile nature and the absence of in-place clearly igneous rocks. A more likely explanation to both the voids and the hollow spheroids is reaction of reduced iron with oxidizing groundwater followed by some re-precipitation as cemented rind concretions at a chemical reaction front. Although some terrestrial concretion analogs are produced from a precursor siderite or pyrite, diagenetic minerals could also be direct precipitates for other terrestrial concretions. The Gale sediments differ from terrestrial sandstones in their high initial iron content, perhaps facilitating a higher occurrence of such diagenetic reactions.

  11. On the electrodynamics of partial discharges in voids in solid dielectrics

    DEFF Research Database (Denmark)

    Pedersen, Aage

    1989-01-01

    It is suggested that a correct interpretation of partial-discharge transients can be obtained only through the concept of induced charge. The application of this concept enables a partial-discharge theory to be developed by means of which the influence of relevant void parameters can be assessed...... measuring techniques, it may lead to quite incorrect conclusions. The relationship between the transients in the applied voltage and current pulses leading to partial breakdown and the induced charge is found...

  12. Paraffin Granuloma Associated with Buried Glans Penis-Induced Sexual and Voiding Dysfunction

    OpenAIRE

    Chon, Wonhee; Koo, Ja Yun; Park, Min Jung; Choi, Kyung-Un; Park, Hyun Jun; Park, Nam Cheol

    2017-01-01

    A paraffinoma is a type of inflammatory lipogranuloma that develops after the injection of an artificial mineral oil, such as paraffin or silicon, into the foreskin or the subcutaneous tissue of the penis for the purpose of penis enlargement, cosmetics, or prosthesis. The authors experienced a case of macro-paraffinoma associated with sexual dysfunction, voiding dysfunction, and pain caused by a buried glans penis after a paraffin injection for penis enlargement that had been performed 35 yea...

  13. Differences in urodynamic voiding variables recorded by conventional cystometry and ambulatory monitoring in symptomatic women

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    Juan Pablo Valdevenito

    2014-10-01

    Full Text Available Objectives To determine whether there are differences in pressure and flow measurements between conventional cystometry (CONV and ambulatory urodynamic monitoring (AMB in women with overactive bladder syndrome and urinary incontinence. Materials and Methods Retrospective study which included female subjects who underwent both CONV (with saline filling medium and AMB, separated by less than 24 months, not using medication active on the lower urinary tract and without history of prior pelvic surgery. Both tests were carried out in compliance with the International Continence Society standards. The paired Student’s t test was used to compare continuous variables. Bland-Altman statistics were used to assess the agreement of each variable between both studies. Results Thirty women with a median (range age of 50 (14 - 73 years met the inclusion criteria. AMB was carried out at a mean (SD of 11 (6 months after CONV. Measurements of pves and pabd at the end of filling, and Qmax were significantly higher from AMB recordings. There were no differences in pdet at the end of filling, pdetQmax or pdetmax during voiding, nor significant difference in Vvoid. Conclusions We provide previously undocumented comparative voiding data between CONV and AMB for patients who most commonly require both investigations. Our findings show higher values of Qmax but similar values of pdetQmax measured by AMB which may partly reflect an overall lower catheter caliber, physiological filling but perhaps also more ‘normal’ voiding conditions.

  14. Sedation with midazolam for voiding cystourethrography in children: a randomised double-blind study

    Energy Technology Data Exchange (ETDEWEB)

    Stokland, E.; Jacobsson, B.; Ljung, B. [Dept. of Paediatric Radiology and Clinical Physiology, The Queen Silvia Children' s Hospital, Gothenburg (Sweden); Andreasson, S. [Dept. of Paediatric Anaesthesiology, The Queen Silvia Children' s Hospital, Gothenburg (Sweden); Jodal, U. [Dept. of Paediatrics, The Queen Silvia Children' s Hospital, Gothenburg (Sweden)

    2003-04-01

    Background: Sedation with midazolam facilitates the performance of diagnostic procedures in children, including voiding cystourethrography (VCUG). However, the influence of sedation on voiding and imaging results have not been adequately evaluated. Objective: Midazolam and placebo were compared to assess discomfort during VCUG and to evaluate if sedation influenced the outcome of the examination. Materials and methods: The study was prospective, randomized and double-blind, and included 95 children, 48 in the midazolam group (median age 2.2 years) and 47 in the placebo group (median age 3.2 years). The evaluation included the child's/parent's experience of the VCUG, as well as the examination results. Results: The children/parents in the midazolam group experienced the VCUG as less distressing compared to those in the placebo group (P < 0.001). Forty-six of 48 children sedated with midazolam could void during the imaging procedure compared to 38 of 47 children given placebo (NS). There was no difference in frequency or grade of vesicoureteric reflux or bladder emptying between the groups. Conclusions: When sedation is required to perform VCUG in children, midazolam can be used without negative effect on the outcome of the examination. (orig.)

  15. Intraspinal stimulation for bladder voiding in cats before and after chronic spinal cord injury

    Science.gov (United States)

    Pikov, Victor; Bullara, Leo; McCreery, Douglas B.

    2007-12-01

    The long-term objective of this study is to develop neural prostheses for people with spinal cord injuries who are unable to voluntarily control their bladder. This feasibility study was performed in 22 adult cats. We implanted an array of microelectrodes into locations in the sacral spinal cord that are involved in the control of micturition reflexes. The effect of microelectrode stimulation was studied under light Propofol anesthesia at monthly intervals for up to 14 months. We found that electrical stimulation in the sacral parasympathetic nucleus at S2 level or in adjacent ventrolateral white matter produced bladder contractions insufficient for inducing voiding, while stimulation at or immediately dorsal to the dorsal gray commissure at S1 level produced strong (at least 20 mmHg) bladder contractions as well as strong (at least 40 mm Hg) external urethral sphincter relaxation, resulting in bladder voiding in 14 animals. In a subset of three animals, spinal cord transection was performed. For several months after the transection, intraspinal stimulation continued to be similarly or even more effective in inducing the bladder voiding as before the transection. We speculate that in the absence of the supraspinal connections, the plasticity in the local spinal circuitry played a role in the improved responsiveness to intraspinal stimulation.

  16. Estimating void fraction in a hydraulic jump by measurements of pixel intensity

    Energy Technology Data Exchange (ETDEWEB)

    Leandro, J.; Carvalho, R. [University of Coimbra, IMAR-CMA, Department of Civil Engineering, Faculty of Science and Technology, Coimbra (Portugal); Chachereau, Y.; Chanson, H. [The University of Queensland, School of Civil Engineering, Brisbane, QLD (Australia)

    2012-05-15

    A hydraulic jump is a sudden transition from supercritical to subcritical flow. It is characterized by a highly turbulent roller region with a bubbly two-phase flow structure. The present study aims to estimate the void fraction in a hydraulic jump using a flow visualization technique. The assumption that the void fraction in a hydraulic jump could be estimated based on images' pixel intensity was first proposed by Mossa and Tolve (J Fluids Eng 120:160-165, 1998). While Mossa and Tolve (J Fluids Eng 120:160-165, 1998) obtained vertically averaged air concentration values along the hydraulic jump, herein we propose a new visualization technique that provides air concentration values in a vertical 2-D matrix covering the whole area of the jump roller. The results obtained are found to be consistent with new measurements using a dual-tip conductivity probe and show that the image processing procedure (IPP) can be a powerful tool to complement intrusive probe measurements. Advantages of the new IPP include the ability to determine instantaneous and average void fractions simultaneously at different locations along the hydraulic jump without perturbing the flow, although it is acknowledged that the results are likely to be more representative in the vicinity of sidewall than at the center of the flume. (orig.)

  17. Contrast-enhanced Voiding Urosonography for Vesicoureteral Reflux Diagnosis in Children.

    Science.gov (United States)

    Duran, Carmina; Beltrán, Viviana P; González, Amàlia; Gómez, Carles; Riego, Javier Del

    2017-10-01

    Contrast-enhanced voiding urosonography (ceVUS) is a dynamic imaging technique that makes it possible to study the structure of the urinary tract after the administration of intravesical contrast material. Initially, ceVUS was indicated mainly to study vesicoureteral reflux (VUR); however, since the ability of ceVUS to depict the structure of the urethra was demonstrated in both sexes, ceVUS is now indicated for examination of the entire urinary tract. The main benefit of ceVUS is that it does not use ionizing radiation. In recent years, fundamental changes have occurred in the understanding of VUR. The lessening effect of VUR and the low rate of occurrence of urethral pathologic conditions have given rise to changes in the indications for tests for these conditions. In addition to being able to help confirm a diagnosis of VUR, the ceVUS technique can be used to depict obstructive and nonobstructive urethral pathologic conditions, as well as normal variants, on high-quality images. Furthermore, ceVUS enables real-time assessment of voiding function. For these reasons, ceVUS should be not only an alternative to voiding cystourethrography, but also the technique of choice for the study of the entire urinary tract in pediatric patients. Online supplemental material is available for this article. ©RSNA, 2017.

  18. [Basaloid Carcinoma of the Esophagus with Lugol-Voiding Lesions--A Case Report].

    Science.gov (United States)

    Shimakawa, Takeshi; Asaka, Shinichi; Shimazaki, Asako; Yamaguchi, Kentaro; Usui, Takebumi; Yokomizo, Hajime; Shiozawa, Shunichi; Yoshimatsu, Kazuhiko; Katsube, Takao; Naritaka, Yoshihiko; Fujibayashi, Mariko

    2015-11-01

    Patients with Lugol-voiding lesions of the esophagus are frequently affected with multiple cancers. Basaloid carcinoma of the esophagus is a very rare disease characterized by growth in the submucosal layer that exhibits a submucosal tumor-like shape. There have been some reports that this type of carcinoma is biologically high-grade. We report a case of metachronous squamous cell carcinoma in situ and superficial basaloid carcinoma in the esophagus with Lugol-voiding lesions. A 63-year-old man underwent gastrectomy for gastric cancer at the age of 45 years. The subsequent surveillance endoscopy found a type 0-Ⅱc lesion in the esophagus in 2000. EMR was thus performed. The pathology showed squamous cell carcinoma in situ. Dysplasia was diagnosed based on the Lugol-voiding lesions, and EMR was performed twice. In 2014, a fourth EMR was performed after a high-grade intraepithelial neoplasia was diagnosed. The pathology showed squamous cell carcinoma in situ and a basaloid carcinoma in the lamina propria, T1a-LPM, ly0, v0, pHMX, pVM0. The patient has had no recurrence for approximately 1 year after the fourth EMR.

  19. NUMERICAL ANALYSIS OF FLAT SLABS WITH SPHERICAL VOIDS SUBJECTED TO SHEAR FORCE

    Directory of Open Access Journals (Sweden)

    Bindea M.

    2015-05-01

    Full Text Available Full flat slabs can be enhanced by using spherical voids to replace the unemployed concrete from the core part of the slab. Therefore we get low self-weighted slabs that can reach a high range of spans, a low material consumption compared to classical solutions used so far. On the other hand, the upsides of these slabs pale against the insecurity in design stage about their punching and shear force behaviour. In this paper it is presented a parametric study about shear force behaviour of flat slabs with spherical voids used in standard condition service. The study was made using the Atena 3D finit element design software, starting form a numerical model gauged on experimental results on real models – scale 1:1. Based on these lab results, the model’s validation was made by overlapping the load – displacement experimental curves on the curves yielded from numerical analyses. The results indicate that under a longitudinal reinforcement rate of lower than 0.50%, flat slabs with spherical voids don’t fail to shear force and over this value the capable shear force decreases in comparison with solid slabs, as the reinforcement rate increases.

  20. Voiding dysfunction in children. Pelvic-floor exercises or biofeedback therapy: a randomized study.

    Science.gov (United States)

    Vasconcelos, Mônica; Lima, Eleonora; Caiafa, Letícia; Noronha, Alessandra; Cangussu, Renata; Gomes, Suzely; Freire, Raquel; Filgueiras, Maria Teresa; Araújo, Junia; Magnus, Gisele; Cunha, Cláudia; Colozimo, Enrico

    2006-12-01

    Fifty-six patients 5.9-15.2 years old with dysfunctional elimination syndrome (DES) unimproved by previous therapies were randomly distributed into two voiding training programs: group 1 contained 26 patients submitted to 24 training sessions over a 3-month period; group 2 contained 30 patients submitted to 16 sessions over a 2-month period. Both groups adhered to a voiding and drinking schedule, received instruction on adequate toilet posture, were reinforced through the maintenance of voiding diaries, and went through proprioceptive and pelvic floor muscle training (Kegel exercises). Group 2 patients also received biofeedback therapy. Clinical evaluation was carried out before each program's initiation and 1, 6, and 12 months after each program's termination. All patients were submitted to renal ultrasonography and dynamic ultrasonography before and 6 months after each program's conclusion. Millivoltage recordings of pelvic floor muscles were compared before and after training. Urinary continence was improved after completion of either training program. Only those patients who received biofeedback training showed a significant decrease in postvoiding residual (PVR) urine as detected by dynamic ultrasonography. Our results show that either training regime can reduce episodic urinary incontinence and urinary tract infection but that further study is required to identify the optimal training duration.