WorldWideScience

Sample records for void filler system

  1. A resorbable antibiotic-eluting polymer composite bone void filler for perioperative infection prevention in a rabbit radial defect model.

    Directory of Open Access Journals (Sweden)

    Benjamin D Brooks

    Full Text Available Nearly 1.3 million total joint replacement procedures are performed in the United States annually, with numbers projected to rise exponentially in the coming decades. Although finite infection rates for these procedures remain consistently low, device-related infections represent a significant cause of implant failure, requiring secondary or revision procedures. Revision procedures manifest several-fold higher infection recurrence rates. Importantly, many revision surgeries, infected or not, require bone void fillers to support the host bone and provide a sufficient tissue bed for new hardware placement. Antibiotic-eluting bone void fillers (ABVF, providing both osteoconductive and antimicrobial properties, represent one approach for reducing rates of orthopedic device-related infections. Using a solvent-free, molten-cast process, a polymer-controlled antibiotic-eluting calcium carbonate hydroxyapatite (HAP ceramic composite BVF (ABVF was fabricated, characterized, and evaluated in vivo using a bacterial challenge in a rabbit radial defect window model. ABVF loaded with tobramycin eliminated the infectious burden in rabbits challenged with a clinically relevant strain of Staphylococcus aureus (inoculum as high as 10⁷ CFU. Histological, microbiological, and radiographic methods were used to detail the effects of ABVF on microbial challenge to host bone after 8 weeks in vivo. In contrast to the HAP/BVF controls, which provided no antibiotic protection and required euthanasia 3 weeks post-operatively, tobramycin-releasing ABVF animals showed no signs of infection (clinical, microbiological, or radiographic when euthanized at the 8-week study endpoint. ABVF sites did exhibit fibrous encapsulation around the implant at 8 weeks. Local antibiotic release from ABVF to orthopedic sites requiring bone void fillers eliminated the periprosthetic bacterial challenge in this 8-week in vivo study, confirming previous in vitro results.

  2. Fillers

    Science.gov (United States)

    McLain, Leslie; Ingle, Danny

    The American Heritage dictionary defines filler as ‘something added to augment weight or size or fill space'. Historically, commercial papermakers have used a variety of inexpensive, minimally beneficiated minerals as fillers for economic extension of more costly wood fibre. As such, these fillers played a relatively inconsequential role in contributing specific quality characteristics to the final sheet. However, as paper grades have evolved, the role of mineral fillers has dramatically expanded to contribute specific functionality to final paper grades. In general, this has resulted in a broader offering of mineral products to the papermaker delivering a range of optical and physical properties. Additionally, the use of mineral fillers may significantly impact dynamics on the paper machine itself. For example, the type and level of filler can dramatically affect chemical demand, drainage, speed and drying rates. A basic understanding of the fundamental characteristics of fillers and their resulting impact, both within the paper matrix and on the paper machine, is a critical requirement for cost-effective grade optimization.

  3. 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.

  4. Voids' System in the Woven Composite Structure

    Institute of Scientific and Technical Information of China (English)

    Pavla VOZKOVA

    2006-01-01

    Composites are common material constructions for high-tech use now. Mechanical properties of woven reinforced composites are influenced by voids inside the structure.Voids could be classified to the two sections. Long and thin cracks are more dangerous than pores. It is important to find relations between preparation and place of occurrence of voids. This paper classifies defects according to rise mechanism, point of occurrence, orientation, size and affect to the properties. Image analysis was used for observing samples. Future work would be oriented not only to observing real samples, but also to calculate mechanical properties from real and ideal structures in 3D woven reinforced composites.

  5. 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.

    2013-01-01

    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

  6. Demineralized Bone Matrix (DBM) as a Bone Void Filler in Lumbar Interbody Fusion: A Prospective Pilot Study of Simultaneous DBM and Autologous Bone Grafts

    Science.gov (United States)

    Kim, Bum-Joon; Kim, Se-Hoon; Lee, Haebin; Lee, Seung-Hwan; Kim, Won-Hyung; Jin, Sung-Won

    2017-01-01

    Objective Solid bone fusion is an essential process in spinal stabilization surgery. Recently, as several minimally invasive spinal surgeries have developed, a need of artificial bone substitutes such as demineralized bone matrix (DBM), has arisen. We investigated the in vivo bone growth rate of DBM as a bone void filler compared to a local autologous bone grafts. Methods From April 2014 to August 2015, 20 patients with a one or two-level spinal stenosis were included. A posterior lumbar interbody fusion using two cages and pedicle screw fixation was performed for every patient, and each cage was packed with autologous local bone and DBM. Clinical outcomes were assessed using the Numeric Rating Scale (NRS) of leg pain and back pain and the Korean Oswestry Disability Index (K-ODI). Clinical outcome parameters and range of motion (ROM) of the operated level were collected preoperatively and at 3 months, 6 months, and 1 year postoperatively. Computed tomography was performed 1 year after fusion surgery and bone growth of the autologous bone grafts and DBM were analyzed by ImageJ software. Results Eighteen patients completed 1 year of follow-up, including 10 men and 8 women, and the mean age was 56.4 (32–71). The operated level ranged from L3/4 to L5/S1. Eleven patients had single level and 7 patients had two-level repairs. The mean back pain NRS improved from 4.61 to 2.78 (p=0.003) and the leg pain NRS improved from 6.89 to 2.39 (posteoporosis. PMID:28264244

  7. Polymethylmethacrylate dermal fillers: evaluation of the systemic toxicity in rats.

    Science.gov (United States)

    Medeiros, C C G; Borghetti, R L; Nicoletti, N; da Silva, V D; Cherubini, K; Salum, F G; de Figueiredo, M A Z

    2014-01-01

    This study evaluated local and systemic reactions after an intravascular injection of polymethylmethacrylate (PMMA) at two concentrations in a murine model. Thirty rats were divided equally into three groups: 2% PMMA, 30% PMMA, and a control group (normal saline only injection). The filler was injected into the ranine vein. The rats were sedated at 7 and 90 days and a clinical evaluation performed. After euthanasia, the right lung, liver, and right kidney were removed, weighed, and microscopically analyzed. The submandibular lymph nodes and tongue were removed and examined microscopically. Serum was subjected to liver and kidney function tests. No groups showed clinical alterations. Microspheres were not observed at any distant organ. Two samples from the 2% PMMA group showed a local inflammatory response at day 7 and another two samples from the 30% PMMA group at day 90. The group injected with 30% PMMA presented higher levels of alanine aminotransferase (P = 0.047) after 90 days when compared with the other groups. The data obtained in this study demonstrate that intravascular injections of PMMA fillers show potential health risks such as chronic inflammation at the implantation site.

  8. Design of capacitance sensor system for void fraction measurement

    Institute of Scientific and Technical Information of China (English)

    LIU Yi-ping; NIU Gang; WANG Jing

    2005-01-01

    Simulation and optimization were applied to a capacitive sensor system based on electrical tomography technology.Sensors, consisting of Morgantown Energy Technology Center (METC) axial synchro driving guard electrodes and two sets of detecting electrodes, make it possible to obtain simultaneously two groups of signals of the void fraction in oil-gas two-phase flow.The computational and experimental results showed that available sensors, charactered by high resolution and fast real-time response can be used for real-time liquid-gas two-phase flow pattern determination.

  9. Properties of hybrid resin composite systems containing prepolymerized filler particles.

    Science.gov (United States)

    Blackham, Jason T; Vandewalle, Kraig S; Lien, Wen

    2009-01-01

    This study compared the properties of newer hybrid resin composites with prepolymerized-filler particles to traditional hybrids and a microfill composite. The following properties were examined per composite: diametral tensile strength, flexural strength/modulus, Knoop microhardness and polymerization shrinkage. Physical properties were determined for each Jason T Blackham, DMD, USAF, General Dentistry, Tyndall composite group (n = 8), showing significant differences between groups per property (p hybrid composites (Z250, Esthet-X) had higher strength, composites containing pre-polymerized fillers (Gradia Direct Posterior, Premise) performed more moderately and the microfill composite (Durafill VS) had lower strength. Premise and Durafill VS had the lowest polymerization shrinkage.

  10. Void Dynamics

    Science.gov (United States)

    Padilla, Nelson D.; Paz, Dante; Lares, Marcelo; Ceccarelli, Laura; Lambas, Diego Garcí A.; Cai, Yan-Chuan; Li, Baojiu

    2016-10-01

    Cosmic voids are becoming key players in testing the physics of our Universe.Here we concentrate on the abundances and the dynamics of voids as these are among the best candidatesto provide information on cosmological parameters. Cai, Padilla & Li (2014)use the abundance of voids to tell apart Hu & Sawicki f(R) models from General Relativity. An interestingresult is that even though, as expected, voids in the dark matter field are emptier in f(R) gravity due to the fifth force expellingaway from the void centres, this result is reversed when haloes are used to find voids. The abundance of voids in this casebecomes even lower in f(R) compared to GR for large voids. Still, the differences are significant and thisprovides a way to tell apart these models. The velocity field differences between f(R) and GR, on the other hand, arethe same for halo voids and for dark matter voids.Paz et al. (2013), concentrate on the velocity profiles around voids. First they show the necessityof four parameters to describe the density profiles around voids given two distinct voidpopulations, voids-in-voids and voids-in-clouds. This profile is used to predict peculiar velocities around voids,and the combination of the latter with void density profiles allows the construction of modelvoid-galaxy cross-correlation functions with redshift space distortions. When these modelsare tuned to fit the measured correlation functions for voids and galaxies in the SloanDigital Sky Survey, small voids are found to be of the void-in-cloud type, whereas largerones are consistent with being void-in-void. This is a novel result that is obtaineddirectly from redshift space data around voids. These profiles can be used toremove systematics on void-galaxy Alcock-Pacinsky tests coming from redshift-space distortions.

  11. Newtonian self-gravitating system in a relativistic huge void universe model

    Science.gov (United States)

    Nishikawa, Ryusuke; Nakao, Ken-ichi; Yoo, Chul-Moon

    2016-12-01

    We consider a test of the Copernican Principle through observations of the large-scale structures, and for this purpose we study the self-gravitating system in a relativistic huge void universe model which does not invoke the Copernican Principle. If we focus on the the weakly self-gravitating and slowly evolving system whose spatial extent is much smaller than the scale of the cosmological horizon in the homogeneous and isotropic background universe model, the cosmological Newtonian approximation is available. Also in the huge void universe model, the same kind of approximation as the cosmological Newtonian approximation is available for the analysis of the perturbations contained in a region whose spatial size is much smaller than the scale of the huge void: the effects of the huge void are taken into account in a perturbative manner by using the Fermi-normal coordinates. By using this approximation, we derive the equations of motion for the weakly self-gravitating perturbations whose elements have relative velocities much smaller than the speed of light, and show the derived equations can be significantly different from those in the homogeneous and isotropic universe model, due to the anisotropic volume expansion in the huge void. We linearize the derived equations of motion and solve them. The solutions show that the behaviors of linear density perturbations are very different from those in the homogeneous and isotropic universe model.

  12. Supplemental topics on voids

    Energy Technology Data Exchange (ETDEWEB)

    Rood, H.J.

    1988-09-01

    Several topics concerning voids are presented, supplementing the report of Rood (1988). The discovery of the Coma supercluster and void and the recognition of the cosmological significance of superclusters and voids are reviewed. Galaxy redshift surveys and redshift surveys for the Abell clusters and very distant objects are discussed. Solar system and extragalactic dynamics are examined. Also, topics for future observational research on voids are recommended. 50 references.

  13. Influence of filler existence on microleakage of a self-etch adhesive system

    Directory of Open Access Journals (Sweden)

    H Mirmohammadi

    2014-01-01

    Full Text Available Aim: This study evaluated the effect of filler existence in self-etch adhesive resin on the marginal leakage of a class V restoration. Materials and Methods: Class V cavities were prepared and restored with a resin composite on the buccal surfaces of 48 premolars lined with unfilled or filled adhesives (n = 24. After thermo cycling, teeth in each group were divided to two subgroups (n = 12, specimens of the first subgroup were incubated for 24 h in distilled water at 37°C, and for the second group three months in the same condition. Specimens were placed in 50% silver nitrate for 24 h at 37°C, and then were cut buccolingually 1 mm thick. Dye penetration was measured using a stereomicroscope and scaled from 0 to 5 in a blind method. SEM images were made to evaluate the dentin-adhesive interfaces. Collected data were analyzed using the nonparametric Kruskal-Wallis and Mann-Whitney U-tests at a significant level of P<0.05. Results: There was no significant difference between microleakage of filled and unfilled adhesive at 24 h and 3 months (P<0.05. There was a significant difference in cervical microleakage between 24 h and 3 months, which was independ on filler load of the adhesive (P<0.001. In contrast, there was no significant difference in occlusal microleakage between 24 h and 3 months and the cervical microleakage was significantly higher than occlusal microleakage after 3 months. SEM images reveald that unfilled adhesive infiltrate slightly better than filled adhesive. Conclusion: The application of filler particles in a self etch adhesive system had no influence on marginal leakage at both the enamel and dentin margins. While the unfilled adhesive infiltrate better than the filled adhesive, its long term performance is not promising.

  14. Wrinkle Fillers

    Science.gov (United States)

    ... packages for authenticity. The FDA is aware of counterfeit products being marketed and used in the U.S. Do ... dermal filler products online, because they could be counterfeit products, or products not approved for use in the ...

  15. Draining the Local Void

    CERN Document Server

    Rizzi, Luca; Shaya, Edward J; Kourkchi, Ehsan; Karachentsev, Igor D

    2016-01-01

    Two galaxies that lie deep within the Local Void provide a test of the expectation that voids expand. The modest (M_B~-14) HI bearing dwarf galaxies ALFAZOAJ1952+1428 and KK246 have been imaged with Hubble Space Telescope in order to study the stellar populations and determine distances from the luminosities of stars at the tip of the red giant branch. The mixed age systems have respective distances of 8.39 Mpc and 6.95 Mpc and inferred line-of-sight peculiar velocities of -114 km/s and -66 km/s toward us and away from the void center. These motions compound on the Milky Way motion of ~230 km/s away from the void. The orbits of the two galaxies are reasonably constrained by a numerical action model encompassing an extensive region that embraces the Local Void. It is unambiguously confirmed that these two void galaxies are moving away from the void center at several hundred km/s.

  16. Responsibility voids

    NARCIS (Netherlands)

    van Hees, M.V.B.P.M; Braham, Matthew

    We present evidence for the existence of 'responsibility voids' in committee decision-making, that is, the existence of situations where no member of a committee can individually be held morally responsible for the outcome. We analyse three types of reasons (causal, normative and epistemic) for the

  17. EPR spectroscopic studies of the process of interaction in a system of liquid phase of the plastic coal mass and thermally unstable carbon filler

    Energy Technology Data Exchange (ETDEWEB)

    Ikonomopulo, V.P.

    1983-01-01

    In conection with discovering the mechanism of coke formation, possible reactions of transient products of thermodestruction in liquid phase-thermally unstable carbon filler systems are studied. The investigations demonstrated that the liquid-phase transient products of one component of the mixture accelerated the process of plastification of solid transient products, and this in turn facilitated the development of the formation of ordered paramagnetic structures. The influence of non-plasticizing thermostable carbon fillers on the thermochemical conversions of liquid phase materials is similar to that of thermostable carbon fillers. A vapor-gas medium is the possible channel of reaction in a liquid phase-solid transient product system. (8 refs.)

  18. Influence of filler existence on microleakage of a self-etch adhesive system

    NARCIS (Netherlands)

    Mirmohammadi, H.; Khosravi, K.; Kashani, K.; Kleverlaan, C.J.; Feilzer, A.J.

    2014-01-01

    Aim: This study evaluated the effect of filler existence in self-etch adhesive resin on the marginal leakage of a class V restoration. Materials and Methods: Class V cavities were prepared and restored with a resin composite on the buccal surfaces of 48 premolars lined with unfilled or filled adhesi

  19. 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.

  20. 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.

  1. Dynamic Response Analysis of an Asymmetric Coupled Vehicle-Track System Generated by Voided Elastic Two-Block Sleeper

    Directory of Open Access Journals (Sweden)

    Zhenxing He

    2016-01-01

    Full Text Available Based on vehicle-track coupled dynamic theory, a three-dimensional asymmetric vehicle-track coupling vibration model is developed to investigate the effect of voided elastic two-block sleepers on vehicle and track system dynamic responses. For the vehicle system, one car body, two frames, and four wheel sets are assumed to be rigid, with 35 degrees of freedom (DOF. For the track system, the rails and the concrete two-block sleepers are the main vibration components. The rails are modelled as Timoshenko beams, and the concrete two-block sleepers are assumed to be rigid mass with vertical and lateral movement. The pads under the rails and the rubber boots under the sleepers provide greater vertical and lateral elasticity for the track. The Hertz nonlinear elastic contact theory is used to calculate the normal wheel/rail force. The wheel/rail tangent creep force is first calculated using Kalker’s linear creep theory and then modified by the Shen-Hedrick-Elkins theory. The results show that the asymmetric voided elastic two-block sleepers have greater effects on the dynamic responses for fasteners and sleepers than on the car body and the wheel/rail forces under measured geometric irregularity and random irregularity. Two or more voided sleepers will greatly affect the vehicle running safety.

  2. Testing thermocline filler materials and molten-salt heat transfer fluids for thermal energy storage systems used in parabolic trough solar power plants.

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, Michael James; Hlava, Paul Frank; Brosseau, Douglas A.

    2004-07-01

    Parabolic trough power systems that utilize concentrated solar energy to generate electricity are a proven technology. Industry and laboratory research efforts are now focusing on integration of thermal energy storage as a viable means to enhance dispatchability of concentrated solar energy. One option to significantly reduce costs is to use thermocline storage systems, low-cost filler materials as the primary thermal storage medium, and molten nitrate salts as the direct heat transfer fluid. Prior thermocline evaluations and thermal cycling tests at the Sandia National Laboratories' National Solar Thermal Test Facility identified quartzite rock and silica sand as potential filler materials. An expanded series of isothermal and thermal cycling experiments were planned and implemented to extend those studies in order to demonstrate the durability of these filler materials in molten nitrate salts over a range of operating temperatures for extended timeframes. Upon test completion, careful analyses of filler material samples, as well as the molten salt, were conducted to assess long-term durability and degradation mechanisms in these test conditions. Analysis results demonstrate that the quartzite rock and silica sand appear able to withstand the molten salt environment quite well. No significant deterioration that would impact the performance or operability of a thermocline thermal energy storage system was evident. Therefore, additional studies of the thermocline concept can continue armed with confidence that appropriate filler materials have been identified for the intended application.

  3. Soy-based fillers for thermoset composites

    Science.gov (United States)

    Watt, Paula

    Considerable work has been done with bio-based fillers in thermoplastics. Wood dust has been used for decades in wood plastic composites in conjunction with recycled high HDPE and PET. In recent years rapidly renewable fillers derived from dried distillery grains and from wood have been introduced commercially for thermoset polymers. These fillers provide bio-content and weight reduction to thermoset molding compounds but issues with moisture absorption and polymerization inhibition have limited their commercial acceptance. The intent of this research was to develop a bio-based filler suitable for thermoset composites. This filler would provide a low density alternative to mined mineral filler, such as CaCO3 or clay. Composites made with these fillers would be lighter in weight, which is desirable for many markets, particularly transportation. Cost parity to the mineral fillers, on a volume basis, was desirable and the use of green chemistry principles was a key objective of the project. This work provides a basis from which further development of modified soy flours as fillers for thermoset composites will continue. Biomass has been evaluated as fillers for thermoset composites since the early 1980s but failed to gain commercial acceptance due to excessive water absorption and inhibition issues with free radical curing. Biomass, with a large percentage of carbohydrates, are very hydrophilic due to their abundance of hydroxyl groups, while biomass, high in lignin, resulted in inhibition of the free radical cure of the unsaturated styrenated polyester matrix systems. Generally protein use as a filler is not desirable due to its food value. Torrefaction has proved to be a good, cost effective, process to reduce hydrophilicity of high cellulose feedstock. Surprising, however, some levels of torrefaction were found to induce the inhibition effect of the filler. Scientific inquiry into this problem proved that aromatics form during the torrefaction process and can

  4. Validation of the thermal-hydraulic system code ATHLET based on selected pressure drop and void fraction BFBT tests

    Energy Technology Data Exchange (ETDEWEB)

    Di Marcello, Valentino, E-mail: valentino.marcello@kit.edu; Escalante, Javier Jimenez; Espinoza, Victor Sanchez

    2015-07-15

    Highlights: • Simulation of BFBT-BWR steady-state and transient tests with ATHLET. • Validation of thermal-hydraulic models based on pressure drops and void fraction measurements. • TRACE system code is used for the comparative study. • Predictions result in a good agreement with the experiments. • Discrepancies are smaller or comparable with respect to the measurements uncertainty. - Abstract: Validation and qualification of thermal-hydraulic system codes based on separate effect tests are essential for the reliability of numerical tools when applied to nuclear power plant analyses. To this purpose, the Institute for Neutron Physics and Reactor Technology (INR) at the Karlsruhe Institute of Technology (KIT) is involved in various validation and qualification activities of different CFD, sub-channel and system codes. In this paper, the capabilities of the thermal-hydraulic code ATHLET are assessed based on the experimental results provided within the NUPEC BFBT benchmark related to key Boiling Water Reactors (BWR) phenomena. Void fraction and pressure drops measurements in the BFBT bundle performed under steady-state and transient conditions which are representative for e.g. turbine trip and recirculation pump trip events, are compared with the numerical results of ATHLET. The comparison of code predictions with the BFBT data has shown good agreement given the experimental uncertainty and the results are consistent with the trends obtained with similar thermal-hydraulic codes.

  5. Influence of Nanodisperse Metal Fillers on the Viscoelastic Properties and Processes of Mechanical Relaxation of Polymer Systems

    Science.gov (United States)

    Kolupav, B. B.; Kolupaev, B. S.; Levchuk, V. V.; Maksimtsev, Yu. R.; Sidletskii, V. A.

    2017-05-01

    The results of research into the viscoelastic properties and processes of mechanical relaxation of polyvinylchloride (PVC) containing Cu nanoparticles obtained by means of electroerosion crushing and electrohydraulic destruction of agglomerates of disperse Cu in the presence of an ultrasonic field are presented. It is shown that, in the case of longitudinal shear deformation at a frequency of 0.4 × 106 s-1 over a wide range of temperatures and content of ingredients, viscoelastic phenomena depending on structural changes in the PVC system occur. An analysis of quantitative results of the elastic and viscoelastic deformation of a body is carried out taking into account the energy and entropy components of interaction of the polymer and filler at their interface.

  6. Neurogenic voiding dysfunction.

    Science.gov (United States)

    Georgopoulos, Petros; Apostolidis, Apostolos

    2017-05-01

    This review aims to analyze and discuss all recently published articles associated with neurogenic voiding discussion providing readers with the most updated knowledge and trigger for further research. They include the proposal of a novel classification system for the pathophysiology of neurogenic lower urinary tract dysfunction (NLUTD) which combines neurological defect in a distinct anatomic location, and data on bowel dysfunction, autonomic dysreflexia and urine biomarkers; review of patient-reported outcome measures in NLUTD; review of the criteria for the diagnosis of clinically significant urinary infections; novel research findings on the pathophysiology of NLUTD; and review of data on minimally and more invasive treatments. Despite the extended evidence base on NLUTD, there is a paucity of high-quality new research concerning voiding dysfunction as opposed to storage problems. The update aims to inform clinicians about new developments in clinical practice, as well as ignite discussion for further clinical and basic research in the aforementioned areas of NLUTD.

  7. Computerized voiding diary.

    Science.gov (United States)

    Rabin, J M; McNett, J; Badlani, G H

    1993-01-01

    An electronic, computerized voiding diary, "Compu-Void" (patent pending) was developed in order to simplify, augment, and automate patients' recording of bladder symptomatology. A voiding diary as a tool has the potential to provide essential information for a more complete diagnostic and therefore therapeutic picture for each patient. Two major problems with the standard written voiding diary have been a lack of patient compliance and the limited amount of information it garners. Twenty-five women with various types of voiding dysfunctions were compared to twenty-five age and parity-matched control women in order to determine patient preferences of the Compu-Void when compared to the standard written voiding diary, compliance with each method, and amount and quality of information obtained with each method. Over 90% of subjects and over 70% of control group patients preferred the Compu-Void over the written diary (P Compu-Void exceeded that obtained with the written method.

  8. Hardness evaluation of PMMA reinforced with two different calcinations temperatures of ZrO2-Al2O3-SiO2 filler system

    Science.gov (United States)

    Hasratiningsih, Z.; Takarini, V.; Cahyanto, A.; Faza, Y.; Asri, L. A. T. W.; Purwasasmita, B. S.

    2017-02-01

    Polymethyl methacrylate (PMMA) is one of the materials used for the temporary crown while making fixed partial dentures. Unfortunately, it has low mechanical properties. This study aim’s to improve PMMA hardness by adding ZrO2-Al2O3-SiO2 filler system in two different calcination temperatures. Thirty-two disc form samples with 8mm diameter x 3mm thickness were made from two category-filler based that had been previously evaluated using Scanning Electron Microscope (SEM). Each category was divided into six groups of three respectively from a controlled and different concentrations of 7(A), 9(B), 11(C), 13(D), and 15(E) weight % of reinforced filler system, then tested with Vickers Hardness Tester. Filler particles that calcined at 550° can increase to 700° consist of fine crystalline and amorphous phases; however, the sample shows the highest hardness about 20,19 VHN even though the increase is only 7,5% compared to control. Meanwhile, the sample that calcined at 700°C exhibiting the highest hardness about 15,66 VHN corresponds to sample D, it has increased 25% compared to the control. This is correlated with microstructure result that has more growth crystalline particles. The results were analyzed by ANOVA which determined were not statistically significantly different (p<0.05). Therefore, it can be concluded that the 13% reinforced ZrO2-Al2O3-SiO2 filler system calcined at 700°C shows the highest hardness increase compare to calcination temperature 550-700°C. Although it is not significantly different.

  9. 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....

  10. The Void Galaxy Survey

    CERN Document Server

    van de Weygaert, R; Platen, E; Beygu, B; van Gorkom, J H; van der Hulst, J M; Aragon-Calvo, M A; Peebles, P J E; Jarrett, T; Rhee, G; Kovac, K; Yip, C -W

    2011-01-01

    The Void Galaxy Survey (VGS) is a multi-wavelength program to study $\\sim$60 void galaxies. Each has been selected from the deepest interior regions of identified voids in the SDSS redshift survey on the basis of a unique geometric technique, with no a prior selection of intrinsic properties of the void galaxies. The project intends to study in detail the gas content, star formation history and stellar content, as well as kinematics and dynamics of void galaxies and their companions in a broad sample of void environments. It involves the HI imaging of the gas distribution in each of the VGS galaxies. Amongst its most tantalizing findings is the possible evidence for cold gas accretion in some of the most interesting objects, amongst which are a polar ring galaxy and a filamentary configuration of void galaxies. Here we shortly describe the scope of the VGS and the results of the full analysis of the pilot sample of 15 void galaxies.

  11. Application of novel catalytic-ceramic-filler in a coupled system for long-chain dicarboxylic acids manufacturing wastewater treatment.

    Science.gov (United States)

    Wu, Suqing; Qi, Yuanfeng; Fan, Chunzhen; He, Shengbing; Dai, Bibo; Huang, Jungchen; Zhou, Weili; Gao, Lei

    2016-02-01

    To gain systematic technology for long-chain dicarboxylic acids (LDCA) manufacturing wastewater treatment, catalytic micro-electrolysis (CME) coupling with adsorption-biodegradation sludge (AB) process was studied. Firstly, novel catalytic-ceramic-filler was prepared from scrap iron, clay and copper sulfate solution and packed in the CME reactor. To remove residual n-alkane and LDCA, the CME reactor was utilized for LDCA wastewater pretreatment. The results revealed that about 94% of n-alkane, 98% of LDCA and 84% of chemical oxygen demand (COD) were removed by the aerated CME reactor at the optimum hydraulic retention time (HRT) of 3.0 h. In this process, catalysis from Cu and montmorillonites played an important role in improving the contaminants removal. Secondly, to remove residual COD in the wastewater, AB process was designed for the secondary biological treatment, about 90% of the influent COD could be removed by biosorption, bio-flocculation and biodegradation effects. Finally, the effluent COD (about 150 mg L(-1)) discharged from the coupled CME-AB system met the requirement of the national discharged standard (COD ≤ 300 mg L(-1)). All of these results suggest that the coupled CME-AB system is a promising technology due to its high-efficient performance, and has the potential to be applied for the real LDCA wastewater treatment. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Polyurethane Filler for Electroplating

    Science.gov (United States)

    Beasley, J. L.

    1984-01-01

    Polyurethane foam proves suitable as filler for slots in parts electroplated with copper or nickel. Polyurethane causes less contamination of plating bath and of cleaning and filtering tanks than wax fillers used previously. Direct cost of maintenance and indirect cost of reduced operating time during tank cleaning also reduced.

  13. Design of a pictogram of the operator-hydraulic filler system

    Energy Technology Data Exchange (ETDEWEB)

    Bukhgol' ts, V.P.; Dinershtein, V.A.

    1985-09-01

    A modern hydraulic filling system is discussed which consists of two lines: the crusher and sorter preparing the filling material, and the hydraulic filling unit, which includes a mixer and a system of pulp conduits. The process chart of the hydraulic filling system without the crusher-sorter is illustrated. When the system is started, water is first flushed through the pulp conduit, gate valves with drives are opened, and the quantity of water discharged is measured by water output sensors. For effective and failure-free operation of the system, remote control and monitoring elements are introduced into the hydraulic filling system.

  14. 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

  15. Study on void fraction distribution in the moderator cell of Cold Neutron Source systems in China Advanced Research Reactor

    Science.gov (United States)

    Li, Liangxing; Li, Huixiong; Hu, Jinfeng; Bi, Qincheng; Chen, Tingkuan

    2007-04-01

    A physical model is developed for analyzing and evaluating the void fraction profiles in the moderator cell of the Cold Neutron Source (CNS) of the China Advanced Research Reactor (CARR), which is now constructing in the China Institute of Atomic Energy (CIAE). The results derived from the model are compared with the related experimental data and its propriety is verified. The model is then used to explore the influence of various factors, including the diameter of boiling vapor bubbles, liquid density, liquid viscosity and the total heating power acted on the moderator cell, on the void fraction profiles in the cell. The results calculated with the present model indicate that the void fraction in the moderator cell increases linearly with heating power, and increases with the liquid viscosity, but decreases as the size of bubbles increases, and increases linearly with heating power. For the case where hydrogen is being used as a moderator, calculation results show that the void fraction in the moderator cell may be less than 30%, which is the maximum void fraction permitted from the nuclear physics point of view. The model and the calculation results will help to obtain insight of the mechanism that controls the void fraction distribution in the moderator cell, and provide theoretical supports for the moderator cell design.

  16. 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.

  17. Modeling cosmic void statistics

    Science.gov (United States)

    Hamaus, Nico; Sutter, P. M.; Wandelt, Benjamin D.

    2016-10-01

    Understanding the internal structure and spatial distribution of cosmic voids is crucial when considering them as probes of cosmology. We present recent advances in modeling void density- and velocity-profiles in real space, as well as void two-point statistics in redshift space, by examining voids identified via the watershed transform in state-of-the-art ΛCDM n-body simulations and mock galaxy catalogs. The simple and universal characteristics that emerge from these statistics indicate the self-similarity of large-scale structure and suggest cosmic voids to be among the most pristine objects to consider for future studies on the nature of dark energy, dark matter and modified gravity.

  18. The sparkling Universe: a scenario for cosmic void motions

    Science.gov (United States)

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

    2016-10-01

    Cosmic voids are prominent features of the Universe, encoding relevant information of the growth and evolution of structure through their dynamics. Here, we perform a statistical study of the global motion of cosmic voids using both a numerical simulation and observational data. Their relation to large-scale mass flows and the physical effects that drive those motions. We analyse the bulk motions of voids, finding void mean bulk velocities in the range 300-400 km s-1, depending on void size and the large-scale environment. Statistically, small voids move faster, and voids in relatively higher density environments have higher bulk velocities. Also, we find large-scale overdensities (underdensities) along (opposite to) the void motion direction, suggesting that void motions respond to a pull-push mechanism. Our analysis suggests that their relative motions are generated by large-scale density fluctuations. In agreement with linear theory, voids embedded in low (high) density regions mutually recede (attract) each other, providing the general mechanism to understand the bimodal behaviour of void motions. We have also inferred void motions in the Sloan Digital Sky Survey using linear theory, finding that their estimated motions are in qualitatively agreement with the results of the simulation. Our results suggest a scenario of galaxies and galaxy systems flowing away from void centres with the additional, and more relevant, contribution of the void bulk motion to the total velocity.

  19. Development of a Neutron Radiography Three-Dimensional Computed Tomography System for Void Fraction Measurement of Boiling Flow in Tight Lattice Rod Bundles

    Science.gov (United States)

    Kureta, Masatoshi

    A neutron radiography three-dimensional computed tomography (NR3DCT) system was developed to visualize the void fraction distribution of boiling flow in tight lattice heated-rod bundles. This paper chiefly reports on the data processing and the error estimation method of NR3DCT. Practical γ-ray noise reduction and image correction techniques were studied to improve the reliability of the experimental data. Using the system and a directly heated 14-rod bundle test section, the behavior of boiling flow in a tight lattice rod bundle was clearly visualized. The effect of each data processing step on the result was also discussed. By this development, the three-dimensional vapor distribution of boiling flow in a heated bundle is made clear, and void fraction databases can be provided for verification of a thermal-hydraulic simulation code.

  20. Dark matter in voids

    Science.gov (United States)

    Fong, Richard; Doroshkevich, Andrei G.; Turchaninov, Victor I.

    1995-07-01

    The theory of the formation of large-scale structure in the universe through the action of gravitational instability imply the existence of substantial amounts of baryonic dark matter, of the order of 50% of the total baryon content in the universe, in the ``voids'' or under-dense regions seen in the large-scale distribution of galaxies. We discuss also the large-scale structure of dark matter expected in voids and the present and future possibilities for the observation of this baryonic dark matter in ``voids.''

  1. Dark matter in voids

    Energy Technology Data Exchange (ETDEWEB)

    Fong, R. [Department of Physics, University of Durham, Durham, DH1 3LE (United Kingdom); Doroshkevich, A.G. [Keldysh Institute of Applied Mathematics, 125047 Moscow (Russian Federation)]|[Teoretical Astrophysics Centrum, Blegsdamsvej 17, Copenhagen DK 2100 (Denmark); Turchaninov, V.I. [Keldysh Institute of Applied Mathematics, 125047 Moscow (Russian Federation)

    1995-07-01

    The theory of the formation of large-scale structure in the universe through the action of gravitational instability imply the existence of substantial amounts of baryonic dark matter, of the order of 50% of the total baryon content in the universe, in the ``voids`` or under-dense regions seen in the large-scale distribution of galaxies. We discuss also the large-scale structure of dark matter expected in voids and the present and future possibilities for the observation of this baryonic dark matter in ``voids.`` {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  2. Preparation of Cathode-Anode Integrated Ceramic Filler and Application in a Coupled ME-EGSB-SBR System for Chlortetracycline Industrial Wastewater Systematic Treatment

    OpenAIRE

    Yuanfeng Qi; Suqing Wu; Fei Xi; Shengbing He; Chunzhen Fan; Bibo Dai; Jungchen Huang; Meng Meng; Xiangguo Zhu; Lei Wang

    2016-01-01

    Chlortetracycline (CTC) contamination of aquatic systems has seriously threatened the environmental and human health throughout the world. Conventional biological treatments could not effectively treat the CTC industrial wastewater and few studies have been focused on the wastewater systematic treatment. Firstly, 40.0 wt% of clay, 30.0 wt% of dewatered sewage sludge (DSS), and 30.0 wt% of scrap iron (SI) were added to sinter the new media (cathode-anode integrated ceramic filler, CAICF). Subs...

  3. Geometrical models for the study of astrophysical systems with spheroidal symmetry imbedded in a standard cosmology: The case of cosmic voids

    CERN Document Server

    Boero, Ezequiel F

    2016-01-01

    We present a class of general prolate and oblate spheroidal spacetimes for the description of cosmic structures in the Universe. They are exact geometries which represent, in an appropriated way, the imbedding of spheroidal matter-energy distributions within a standard cosmological scenario, and therefore they allow for an improved description of a wider class of astrophysical systems from a more accurate point of view. These spacetimes can be used to describe overdensity or underdensity regions; in this work we consider the last case, that is, the description of cosmic voids. We introduce and study a model of void which is a generalization of a simpler one in spherical symmetry and we use it for the calculation of weak lensing optical scalars as a non-trivial and interesting application. In this particular example we show the rich observable features that can be found in such models.

  4. Neural Network Modeling and System Simulating for the Dynamic Process of Varied Gap Pulsed GTAW with Wire Filler

    Institute of Scientific and Technical Information of China (English)

    Guangjun ZHANG; Shanben CHEN; Lin WU

    2005-01-01

    As the base of the research work on the weld shape control during pulsed gas tungsten arc welding (GTAW) with wire filler, this paper addressed the modeling of the dynamic welding process. Topside length Lt, maximum width Wt and half-length ratio Rh1 were selected to depict topside weld pool shape, and were measured on-line by vision sensing. A dynamic neural network model was constructed to predict the usually unmeasured backside width and topside height of the weld through topside shape parameters and welding parameters. The inputs of the model were the welding parameters (peak current, pulse duty ratio, welding speed, filler rate), the joint gap, the topside pool shape parameters (Lt, Wt, and Rhl), and their history values at two former pulse, a total of 24 numbers. The validating experiment results proved that the artificial neural network (ANN) model had high precision and could be used in process control. At last, with the developed dynamic model, steady and dynamic behavior was analyzed by simulation experiments, which discovered the variation rules of weld pool shape parameters under different welding parameters, and further knew well the characteristic of the welding process.

  5. 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

    2007-01-12

    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. We also discuss a technique for optimizing the calculation of fine-scale information on the fly for use in a coarse-scale simulation, and discuss the specific case of a fine-scale model that calculates void growth explicitly feeding into a coarse-scale mechanics model to study damage localization.

  6. Sodium voiding analysis in Kalimer

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Won-Pyo; Jeong, Kwan-Seong; Hahn, Dohee [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    2001-07-01

    A sodium boiling model has been developed for calculations of the void reactivity feedback as well as the fuel and cladding temperatures in the KALIMER core after onset of sodium boiling. The sodium boiling in liquid metal reactors using sodium as coolant should be modeled because of phenomenon difference observed from that in light water reactor systems. The developed model is a multiple -bubble slug ejection model. It allows a finite number of bubbles in a channel at any time. Voiding is assumed to result from formation of bubbles that fill the whole cross section of the coolant channel except for liquid film left on the cladding surface. The vapor pressure, currently, is assumed to be uniform within a bubble. The present study is focused on not only demonstration of the sodium voiding behavior predicted by the developed model, but also confirmation on qualitative acceptance for the model. In results, the model catches important phenomena for sodium boiling, while further effort should be made for the complete analysis. (author)

  7. 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.

  8. 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.

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

    DEFF Research Database (Denmark)

    Holbøll, Joachim; Henriksen, Mogens

    1992-01-01

    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...

  10. Void shape effects and voids starting from cracked inclusion

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    2011-01-01

    Numerical, axisymmetric cell model analyses are used to study the growth of voids in ductile metals, until the mechanism of coalescence with neighbouring voids sets in. A special feature of the present analyses is that extremely small values of the initial void volume fraction are considered, dow...

  11. Alternative Fillers for the Production of Bituminous Mixtures: A Screening Investigation on Waste Powders

    Directory of Open Access Journals (Sweden)

    Cesare Sangiorgi

    2017-06-01

    Full Text Available There has been a significant increase in the demand for using recycled materials in construction because of the lack and limitation of available natural resources. A number of industrial and domestic waste products are being used in the replacement of traditional materials for road construction, and many studies have been carried out in recent years on the use of different recycled materials in substitution of conventional fillers in Asphalt Concretes (AC. The aim of this laboratory research is to analyze the physical characteristics of three different recycled fillers and compare them with those of a traditional limestone filler. The alternative fillers presented in this paper are: a waste bleaching clay that comes from two consecutive stages in the industrial process for decolouring vegetable oils and producing biogas (Ud filler, a dried mud waste from a tungsten mine (MW filler and a recycled glass powder (Gl filler. Results show significant differences between the fillers, and, in particular, Rigden Voids (RV seem to have the largest potential influence on the rheology of ACs.

  12. 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.

  13. Effects of void size and gas content on electrical breakdown in lightweight, mechanically compliant, void-filled dielectrics

    Science.gov (United States)

    Anderson, R. A.; Lagasse, R. R.; Russick, E. M.; Schroeder, J. L.

    2002-03-01

    Dielectric potting materials (encapsulants) are used to prevent air breakdown in high-voltage electrical devices. We report breakdown strengths in void-filled encapsulants, stressed with unipolar voltage pulses of the order of 10 μs duration. High strengths, on the order of 100 kV mm-1, are measured under these test conditions. The materials studied include low-density open celled gel-derived foams with cell sizes of 4 μm or less, closed celled CO2-blown polystyrene and urethane foams, and epoxies containing 48 vol % of hollow glass microballoon (GMB) fillers. These last specimens varied the void gas (N2 or SO2) and also the void diameters (tens to hundreds of μm). Our measurements are thought to be directly sensitive to the rate of field-induced ionization events in the void gas; however, the breakdown strengths of the materials tested appeared to vary in direct proportion with the conventional Paschen-law gas-discharge inception threshold, the electric stress at which gas-ionization avalanches become possible. The GMB-epoxy specimens displayed this type of dependence of breakdown strength on the void-gas density and void size, but the measurements were an order of magnitude above the conventional predictions. Small-celled foams also showed increased breakdown strengths with decreased cell size, although their irregular void geometry prevented a direct comparison with the more uniformly structured microballoon-filled encapsulants. The experimental observations are consistent with a breakdown mechanism in which the discharge of a few voids can launch a full breakdown in the composite material.

  14. Analysis of Void Fraction Distribution and Departure from Nucleate Boiling in Single Subchannel and Bundle Geometries Using Subchannel, System, and Computational Fluid Dynamics Codes

    Directory of Open Access Journals (Sweden)

    Taewan Kim

    2012-01-01

    Full Text Available In order to assess the accuracy and validity of subchannel, system, and computational fluid dynamics codes, the Paul Scherrer Institut has participated in the OECD/NRC PSBT benchmark with the thermal-hydraulic system code TRACE5.0 developed by US NRC, the subchannel code FLICA4 developed by CEA, and the computational fluid dynamic code STAR-CD developed by CD-adapco. The PSBT benchmark consists of a series of void distribution exercises and departure from nucleate boiling exercises. The results reveal that the prediction by the subchannel code FLICA4 agrees with the experimental data reasonably well in both steady-state and transient conditions. The analyses of single-subchannel experiments by means of the computational fluid dynamic code STAR-CD with the CD-adapco boiling model indicate that the prediction of the void fraction has no significant discrepancy from the experiments. The analyses with TRACE point out the necessity to perform additional assessment of the subcooled boiling model and bulk condensation model of TRACE.

  15. A computerized voiding diary.

    Science.gov (United States)

    Rabin, J M; McNett, J; Badlani, G H

    1996-11-01

    To examine a group of subject and control patient's preferences and compliance with regard to the Compu-Void (CV) electronic voiding diary as compared to the written diary (WD) and to compare the two methods with respect to the type of information obtained and whether the order of use of each method influenced results in the subject group. Thirty-six women between the ages of 20 and 84 with bladder symptoms were compared to a group of 36 age-matched women. In 100% of subjects and 95% of control patients, CV entries exceeded the number made with the WD in voiding events and, in subjects, in incontinence episodes recorded (P < .005 and P < .005, respectively). Over 98% of subjects and over 80% of controls preferred the CV (P < .0005). The order of use of each method in subjects made no significant difference with regard to the volume of information obtained (P < .407), number of leakage events recorded (P < .494) or fluid intake patterns (P < .410). Patients' compliance with each method was not affected by the order of use. Our results suggest an increased volume of data and greater patient compliance in reporting bladder symptoms and events using the CV and that the order of use is not important.

  16. THE INSTABILITY OF THE DIFFUSION-CONTROLLED GRAIN-BOUNDARY VOID IN STRESSED SOLID

    Institute of Scientific and Technical Information of China (English)

    王华; 李中华

    2003-01-01

    As atoms migrate along a void surface and grain-boundary, driven by various thermodynamic forces, the grain-boundary void changes its shape and volume. When the void changes its configuration, the free energy of the system also changes. In this article, the free energy is calculated for an evolving grain-boundary void filled with gas in a stressed solid. Then the instability conditions and the equilibrium shape of the void are determined as a function of the grain-boundary and surface energies, the void volume, the externally applied stresses, as well as the internal pressure built up by the gas filled in the void.

  17. 用改进ECT技术测定油气两相流中空泡分数的测量研究%Void Fraction Measurement in Oil-Gas Transportation Pipeline Using an Improved Electrical Capacitance Tomography System

    Institute of Scientific and Technical Information of China (English)

    牛刚; 贾志海; 王经

    2004-01-01

    To measure the void fraction online in oil-gas pipeline, an improved electrical capacitance tomography(ECT) system has been designed. The capacitance sensor with new structure has twelve internal electrodes and overcomes the influence of the pipe wall. The data collection system is improved by using high performance IC(integrated circuit). Static tests of bubble flow, stratified flow and annular flow regime are carried out. Measurements are taken on bubble flow, stratified flow and slug flow. Results show that the new ECT system performs well on void fraction measurement of bubble flow and stratified flow, but the error of measurement for slug flow is more than 10%.

  18. Preparation of Cathode-Anode Integrated Ceramic Filler and Application in a Coupled ME-EGSB-SBR System for Chlortetracycline Industrial Wastewater Systematic Treatment

    Directory of Open Access Journals (Sweden)

    Yuanfeng Qi

    2016-01-01

    Full Text Available Chlortetracycline (CTC contamination of aquatic systems has seriously threatened the environmental and human health throughout the world. Conventional biological treatments could not effectively treat the CTC industrial wastewater and few studies have been focused on the wastewater systematic treatment. Firstly, 40.0 wt% of clay, 30.0 wt% of dewatered sewage sludge (DSS, and 30.0 wt% of scrap iron (SI were added to sinter the new media (cathode-anode integrated ceramic filler, CAICF. Subsequently, the nontoxic CAICF with rough surface and porous interior packed into ME reactor, severing as a pretreatment step, was effective in removing CTC residue and improving the wastewater biodegradability. Secondly, expanded granular sludge bed (EGSB and sequencing batch reactor (SBR, serving as the secondary biological treatment, were mainly focusing on chemical oxygen demand (COD and ammonia nitrogen (NH3-N removal. The coupled ME-EGSB-SBR system removed about 98.0% of CODcr and 95.0% of NH3-N and the final effluent met the national discharged standard (C standard of CJ 343-2010, China. Therefore, the CTC industrial wastewater could be effectively treated by the coupled ME-EGSB-SBR system, which has significant implications for a cost-efficient system in CTC industrial systematic treatment and solid wastes (DSS and SI treatment.

  19. Into the Void

    Science.gov (United States)

    2006-01-01

    17 May 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a portion of a chain of pits on a lava- and dust-covered plain northwest of Tharsis Tholus -- one of the many volcanic constructs in the Tharsis region of Mars. Pit chains, such as this one, are associated with the collapse of surface materials into subsurface voids formed by faulting and expansion -- or extension -- of the bedrock. Location near: 16.4oN, 92.6oW Image width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Winter

  20. [Rhinoplasty and dermal fillers].

    Science.gov (United States)

    Jallut, Y; Nguyen, P S

    2014-12-01

    The use of fillers for camouflage after surgical rhinoplasty or during medical rhinoplasty process represent an attractive technique which allows to avoid or to delay surgical time often dreaded by the patients. This technique apparently quite simple, must be applied carefully in order to avoid possible complications that can sometimes be very serious. Through their seven years of experience, the authors have selected absorbable type of products: hyaluronic acid or calcium hydroxylapatite, both approved by ANSM. Preference is given to microcannulas (27G) over needles and injection techniques through multiple tunnels fitted with small fragmented boluses. Due to possible Tyndall effect and skin necrosis risk, a one-shot injection with a lot of product should be avoided. Calcium hydroxyapaptite is preferred for the dorsum area while hyaluronic acid is recommended for the tip. The authors also relate the major encountered complications and describe the appropriated treatments. Nevertheless the strict application of the described technique represents the best way to prevent adverse complications.

  1. 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...

  2. Dielectric properties of inorganic fillers filled epoxy thin film

    Energy Technology Data Exchange (ETDEWEB)

    Norshamira, A., E-mail: myra.arshad@gmail.com; Mariatti, M., E-mail: mariatti@usm.my [School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Pulau Pinang (Malaysia)

    2015-07-22

    The demand on the small size and high performance electronics has driven changes in the electronic packaging requirements from discrete capacitor to embedded capacitor. Embedded capacitor can improve electrical performance compared with discrete capacitor. This study aimed to achieve high dielectric of epoxy thin film composite that were targeted for application as embedded capacitor. In this study, inorganic fillers such as Calcium Copper Titanate (CCTO), Iron(III) Oxide (Fe{sub 2}O{sub 3}) and Titanium Dioxide (TiO{sub 2}) were loaded in epoxy system at 5 and 20vol%. Morphology and dielectric properties were investigated to identify the effect of fillers loading and types of fillers on the properties of epoxy thin film composite. Based on the study, CCTO with 20vol% loading was found to have good dielectric properties compared to other type of fillers.

  3. Testing Gravity using Void Profiles

    Science.gov (United States)

    Cai, Yan-Chuan; Padilla, Nelson; Li, Baojiu

    2016-10-01

    We investigate void properties in f(R) models using N-body simulations, focusing on their differences from General Relativity (GR) and their detectability. In the Hu-Sawicki f(R) modified gravity (MG) models, the halo number density profiles of voids are not distinguishable from GR. In contrast, the same f(R) voids are more empty of dark matter, and their profiles are steeper. This can in principle be observed by weak gravitational lensing of voids, for which the combination of a spectroscopic redshift and a lensing photometric redshift survey over the same sky is required. Neglecting the lensing shape noise, the f(R) model parameter amplitudes fR0=10-5 and 10-4 may be distinguished from GR using the lensing tangential shear signal around voids by 4 and 8 σ for a volume of 1 (Gpc/h)3. The line-of-sight projection of large-scale structure is the main systematics that limits the significance of this signal for the near future wide angle and deep lensing surveys. For this reason, it is challenging to distinguish fR0=10-6 from GR. We expect that this can be overcome with larger volume. The halo void abundance being smaller and the steepening of dark matter void profiles in f(R) models are unique features that can be combined to break the degeneracy between fR0 and σ8.

  4. PRECISION COSMOGRAPHY WITH STACKED VOIDS

    Energy Technology Data Exchange (ETDEWEB)

    Lavaux, Guilhem [Department of Physics, University of Illinois at Urbana-Champaign, 1002 West Green Street, Urbana, IL 61801 (United States); Wandelt, Benjamin D. [UPMC Univ Paris 06, UMR 7095, Institut d' Astrophysique de Paris, 98 bis, boulevard Arago, 75014 Paris (France)

    2012-08-01

    We present a purely geometrical method for probing the expansion history of the universe from the observation of the shape of stacked voids in spectroscopic redshift surveys. Our method is an Alcock-Paczynski (AP) test based on the average sphericity of voids posited on the local isotropy of the universe. It works by comparing the temporal extent of cosmic voids along the line of sight with their angular, spatial extent. We describe the algorithm that we use to detect and stack voids in redshift shells on the light cone and test it on mock light cones produced from N-body simulations. We establish a robust statistical model for estimating the average stretching of voids in redshift space and quantify the contamination by peculiar velocities. Finally, assuming that the void statistics that we derive from N-body simulations is preserved when considering galaxy surveys, we assess the capability of this approach to constrain dark energy parameters. We report this assessment in terms of the figure of merit (FoM) of the dark energy task force and in particular of the proposed Euclid mission which is particularly suited for this technique since it is a spectroscopic survey. The FoM due to stacked voids from the Euclid wide survey may double that of all other dark energy probes derived from Euclid data alone (combined with Planck priors). In particular, voids seem to outperform baryon acoustic oscillations by an order of magnitude. This result is consistent with simple estimates based on mode counting. The AP test based on stacked voids may be a significant addition to the portfolio of major dark energy probes and its potentialities must be studied in detail.

  5. A PRELIMINARY INVESTIGATION INTO THE USE OF ACID-TOLERANT PRECIPITATED CALCIUM CARBONATE FILLERS IN PAPERMAKING OF DEINKED PULP DERIVED FROM RECYCLED NEWSPAPER

    Directory of Open Access Journals (Sweden)

    Jing Shen

    2009-08-01

    Full Text Available The use of acid-tolerant precipitated calcium carbonate fillers, including phosphoric acid/sodium hexametaphosphate modified precipitated CaCO3 filler, and sodium silicate/phosphoric acid/sodium hexametaphos-phate modified precipitated CaCO3 filler in papermaking of deinked pulp derived from recycled newspaper was explored. These two acid-tolerant fillers provided considerably more brightness improvement in papers in comparison the unmodified filler, presumably indicating alleviated pulp darkening achieved as a result of better acid-resistant properties. The addition of acid-tolerant fillers into the furnish slurries gave lower system pH as compared with unmodified filler. Among the three fillers used in this work, the effect on retention of modification of the filler with sodium silicate/phosphoric acid/sodium hexametaphosphate was probably the best, as evaluated from ash content measurements. For air permeability of the paper, the use of acid-tolerant fillers provided slightly more improvement in comparison to the unmodified filler. For tensile and burst strength of the paper, the use of sodium silicate/phosphoric acid/sodium hexameta-phosphate modified precipitated calcium carbonate filler gave better results as compared with the other two fillers. Additionally, the improving effect of acid-tolerant fillers on furnish static drainage was found to be slightly weaker than that of unmodified filler.

  6. Polarization transfer kinetics in a binary system of molecular luminescense centers in nanopores with a liquid crystal filler

    Science.gov (United States)

    Kucherenko, M. G.; Palem, A. A.

    2008-04-01

    We have studied the anisotropic activated luminescence of molecular centers introduced into spherical nanopores filled with a nematic liquid crystal possessing a homeotropic texture. The kinetics of the anisotropy of emission from these centers is traced during selective pulsed activation of the donor subsystem by a linearly polarized light in the case where the long-range nonradiative transfer of the electron excitation energy to the acceptor molecules takes place in a radially aligned two-component luminescent system. A theoretical model is proposed that takes into account the migration of excitations over the system of donor centers. Dependences of the kinetics of the anisotropy of acceptor luminescence on the nanopore radius, the Förster transfer rate, and some other parameters have been determined. A change in the sign of polarization of the activated luminescence signal has been observed.

  7. Inhibiting the growth of Cu3Sn and Kirkendall voids in the Cu/Sn-Ag-Cu system by minor Pd alloying

    Science.gov (United States)

    Ho, Cheng En; Kuo, Tsai Tung; Wang, Chun Chien; Wu, Wei Hsiang

    2012-10-01

    In this study, the metallurgical reaction between Cu substrates (electrolytic type) and a Sn3Ag0.5Cu-xPd alloy at 180°C was examined using a scanning electron microscope (SEM), electron probe microanalyzer (EPMA), focused ion beam (FIB) microscope, and transmission electron microscope (TEM). The results showed that the growth of Cu3Sn in the Cu/Sn-Ag-Cu solder joints was substantially suppressed by doping with a minor quantity of Pd (0.1-0.7 wt. %) in the solder alloy. The sluggish growth of Cu3Sn reduced the formation of Kirkendall voids at the Cu/Cu3Sn interface and significantly improved the mechanical reliability of the joint interface. It was argued that a minor addition of Pd into the solder stabilized the Cu6Sn5 phase and enlarged the interdiffusion coefficient of Cu6Sn5 but diminished that of the neighboring phase (Cu3Sn), thereby decreasing the Kirkendall effect in the Cu/Sn-Ag-Cu reactive system.

  8. 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.

  9. Geometry and scaling of cosmic voids

    CERN Document Server

    Gaite, Jose

    2008-01-01

    CONTEXT: Cosmic voids are observed in the distribution of galaxies and, to some extent, in the dark matter distribution. If these distributions have fractal geometry, it must be reflected in the geometry of voids; in particular, we expect scaling sizes of voids. However, this scaling is not well demonstrated in galaxy surveys yet. AIMS: Our objective is to understand the geometry of cosmic voids in relation to a fractal structure of matter. We intend to distinguish monofractal voids from multifractal voids, regarding their scaling properties. We plan to analyse voids in the distributions of mass concentrations (halos) in a multifractal and their relation to galaxy voids. METHODS: We make a statistical analysis of point distributions based on the void probability function and correlation functions. We assume that voids are spherical and devise a simple spherical void finder. For continuous mass distributions, we employ the methods of fractal geometry. We confirm the analytical predictions with numerical simula...

  10. 46 CFR 154.1210 - Hold space, void space, cofferdam, and spaces containing cargo piping.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Hold space, void space, cofferdam, and spaces containing... Design, Construction and Equipment Cargo Area: Mechanical Ventilation System § 154.1210 Hold space, void space, cofferdam, and spaces containing cargo piping. (a) Each hold space, void space, cofferdam,...

  11. Three-Dimensional Molecular Dynamics Simulations of Void Coalescence during Dynamic Fracture of Ductile Metals

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-09-02

    Void coalescence and interaction in dynamic fracture of ductile metals have been investigated using 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. The interaction of the voids is not reflected in the volumetric asymptotic growth rate of the voids, as demonstrated here. Finally, the practice of using a single void and periodic boundary conditions to study coalescence is examined critically and shown to produce results markedly different than the coalescence of a pair of isolated voids.

  12. Pulsed electrical breakdown of a void-filled dielectric

    Science.gov (United States)

    Anderson, R. A.; Lagasse, R. R.; Schroeder, J. L.

    2002-05-01

    We report breakdown strengths in a void-filled dielectric material, epoxy containing 48 vol % hollow glass microballoon filler, which is stressed with unipolar voltage pulses of the order of 10 μs duration. The microballoon voids had mean diameters of approximately 40 μm and contained SO2 gas at roughly 30% atmospheric pressure. This void-filled material displays good dielectric strength (of the order of 100 kV mm-1) under these short-pulse test conditions. Results from a variety of electrode geometries are reported, including arrangements in which the electric stress is highly nonuniform. Conventional breakdown criteria based on mean or peak electric stress do not account for these data. A statistics-based predictive breakdown model is developed, in which the dielectric is divided into independent, microballoon-sized "discharge cells" and the spontaneous discharge of a single cell is presumed to launch full breakdown of the composite. We obtain two empirical parameters, the mean and standard deviation of the spontaneous discharge field, by fitting breakdown data from two electrode geometries having roughly uniform fields but with greatly differing volumes of electrically stressed material. This model accounts for many aspects of our data, including the inherent statistical scatter and the dependence on the stressed volume, and it provides informative predictions with electrode geometries giving highly nonuniform fields. Issues related to computational spatial resolution and cutoff distance are also discussed.

  13. The Void Galaxy Survey: Galaxy Evolution and Gas Accretion in Voids

    Science.gov (United States)

    Kreckel, Kathryn; van Gorkom, Jacqueline H.; Beygu, Burcu; van de Weygaert, Rien; van der Hulst, J. M.; Aragon-Calvo, Miguel A.; Peletier, Reynier F.

    2016-10-01

    Voids represent a unique environment for the study of galaxy evolution, as the lower density environment is expected to result in shorter merger histories and slower evolution of galaxies. This provides an ideal opportunity to test theories of galaxy formation and evolution. Imaging of the neutral hydrogen, central in both driving and regulating star formation, directly traces the gas reservoir and can reveal interactions and signs of cold gas accretion. For a new Void Galaxy Survey (VGS), we have carefully selected a sample of 59 galaxies that reside in the deepest underdensities of geometrically identified voids within the SDSS at distances of ~100 Mpc, and pursued deep UV, optical, Hα, IR, and HI imaging to study in detail the morphology and kinematics of both the stellar and gaseous components. This sample allows us to not only examine the global statistical properties of void galaxies, but also to explore the details of the dynamical properties. We present an overview of the VGS, and highlight key results on the HI content and individually interesting systems. In general, we find that the void galaxies are gas rich, low luminosity, blue disk galaxies, with optical and HI properties that are not unusual for their luminosity and morphology. We see evidence of both ongoing assembly, through the gas dynamics between interacting systems, and significant gas accretion, seen in extended gas disks and kinematic misalignments. The VGS establishes a local reference sample to be used in future HI surveys (CHILES, DINGO, LADUMA) that will directly observe the HI evolution of void galaxies over cosmic time.

  14. On cavitation instabilities with interacting voids

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    2012-01-01

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

  15. 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 pro

  16. 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

  17. B218 Weld Filler Wire Characterization for Al-Li Alloy 2195

    Science.gov (United States)

    Bjorkman, Gerry; Russell, Carolyn

    2000-01-01

    NASA Marshall Space Flight Center, Lockheed Martin Space Systems- Michoud Operations, and McCook Metals have developed an aluminum-copper weld filler wire for fusion welding aluminum lithium alloy 2195. The aluminum-copper based weld filler wire has been identified as B218, a McCook Metals designation. B218 is the result of six years of weld filler wire development funded by NASA, Lockheed Martin, and McCook Metals. The filler wire chemistry was developed to produce enhanced 2195 weld and repair weld mechanical properties over the 4043 aluminum-silicon weld filler wire, which is currently used to weld 2195 on the Super Lightweight External Tank for the NASA Space Shuttle Program. An initial characterization was performed consisting of a repair weld evaluation using B218 and 4043 weld filler wires. The testing involved room temperature and cryogenic repair weld tensile testing along with fracture toughness testing. From the testing, B218 weld filler wire produce enhanced repair weld tensile strength, ductility, and fracture properties over 4043. B218 weld filler wire has proved to be a superior weld filler wire for welding aluminum lithium alloy 2195 over 4043.

  18. Precision cosmography with stacked voids

    CERN Document Server

    Lavaux, Guilhem

    2011-01-01

    We present a purely geometrical method for probing the expansion history of the Universe from the observation of the shape of stacked voids in spectroscopic re dshift surveys. Our method is an Alcock-Pasczinsky test based on the average sphericity of voids posited on the local isotropy of the Universe. It works by comparing the temporal extent of cosmic voids along the line of sight with their angular, spatial extent. We describe the algorithm that we use to detect and stack voids in redshift shells on the light cone and test it on mock light cones produced from N-body simulations. We establish a robust statistical model for estimating the average stretching of voids in redshift space and quantify the contamination by peculiar velocities. Finally, we assess the capability of this approach to constrain dark energy parameters in terms of the figure of merit (FoM) of the dark energy task force and in particular of the proposed Euclid mission which is particularly suited for this technique since it is a spectrosc...

  19. Partial discharges within two spherical voids in an epoxy resin

    Science.gov (United States)

    Illias, H. A.; Chen, G.; Bakar, A. H. A.; Mokhlis, H.; Tunio, M. A.

    2013-08-01

    A void in a dielectric insulation material may exist due to imperfection in the insulation manufacturing or long term stressing. Voids have been identified as one of the common sources of partial discharge (PD) activity within an insulation system, such as in cable insulation and power transformers. Therefore, it is important to study PD phenomenon within void cavities in insulation. In this work, a model of PD activity within two spherical voids in a homogeneous dielectric material has been developed using finite element analysis software to study the parameters affecting PD behaviour. The parameters that have been taken into account are the void surface conductivity, electron generation rate and the inception and extinction fields. Measurements of PD activity within two spherical voids in an epoxy resin under ac sinusoidal applied voltage have also been performed. The simulation results have been compared with the measurement data to validate the model and to identify the parameters affecting PD behaviour. Comparison between measurements of PD activity within single and two voids in a dielectric material have also been made to observe the difference of the results under both conditions.

  20. "Compu-Void II": the computerized voiding diary.

    Science.gov (United States)

    Rabin, J M; McNett, J; Badlani, G H

    1996-02-01

    We have previously described an electronic voiding diary, "Compu-Void" (Copyright, 1990) developed to automate recording of bladder symptoms (Rabin et al., 1993). Our objectives in this, the second phase of this study, were to examine a group of subject and control patients' preference and compliance with regard to the "Compu-Void" (CV) compared to the standard written voiding diary (WD), to compare the two methods with respect to the amount and type of information obtained and to determine whether or not the order of use of each recording method influenced results in the subject group. Thirty-six women between the ages of 20 and 84 with bladder symptomatology were compared to a group 36 age-matched women. In 100% of subjects and 95% of control patients, CV entries exceeded the number made with the WD in voiding events and in subjects, in incontinent episodes recorded (P < 0.0005 and P < 0.005, respectively). Over 98% of subjects and over 80% of control patients preferred CV over the WD (p < 0.0005). The order of use of each recording method in subjects made no significant difference with regard to the volume of information obtained (p < 0.407), number of urinary leakage events recorded (p < 0.494), and fluid intake patterns (p < 0.410). Patient impressions of, and compliance with each method were not affected by order of use. The only difference regarding order of use was that most subjects who used the CV first also found the WD to be tedious (61% vs 14%). Our results suggest increased volume of data and of patient compliance in reporting bladder symptoms and events using CV, and that order of use is not an important factor in determining patient impressions of the two methods. The majority of subject and control patients preferred CV over traditional methods. An updated version of the software and hardware is also included.

  1. Effect of filler size on wear resistance of resin cement.

    Science.gov (United States)

    Shinkai, K; Suzuki, S; Katoh, Y

    2001-11-01

    The purpose of this study was to evaluate the effect of filler size on the wear of resin cements. Materials tested included four experimental dual-cure resin cements (Kuraray) consisting of different-sized filler particles. A rectangular box cavity was prepared on the flattened occlusal surface of extracted human molars. Ceramic inlays for the cavities were fabricated using the Cerec 2 system. The Cerec inlays were cemented with the respective cements and adhesive systems according to the manufacturer's directions. The restored surface was finished by wet-grinding with an 800-grit silicon carbide paper. Six specimens were prepared for each resin cement. Half of the specimens were subjected to a three-body wear test for 200,000 cycles, and the others were subjected to a toothbrush abrasion test for 30,000 cycles. The worn surface of each restoration was scanned by a profilometer (Surfcom 475 A) at eight different points for each restoration. The wear value was determined by measuring the vertical gap depth on the profilometric tracings. The data were statistically analyzed by one-way analysis of variance (ANOVA) and Scheffe's test. The results showed that, with increase of filler size, the wear value decreased in the toothbrush test and increased in the three-body wear test. The cement with 0.04-microm filler exhibited the lowest wear value among the materials in the three-body wear test, and the same wear value as the cement with 0.97-microm filler in the toothbrush test. Based upon the results of this study, it is concluded that the wear of resin cements was affected by the filler size as well as the mode of wear test.

  2. Effect of three filler types on mechanical properties of dental composite

    Directory of Open Access Journals (Sweden)

    Pahlavan A.

    2005-06-01

    Full Text Available Statement of Problem: Despite the improvements achieved in the field of dental composites, their strength, longevity, and service life specially in high stress areas is not confirmed. Finding better fillers can be a promising step in this task. Purpose: The purpose of this study was to investigate the effect of the filler type on the mechanical properties of a new experimental dental composite and compare these with the properties of composite containing conventional glass filler. Materials and Methods: Experimental composites were prepared by mixing silane-treated fillers with monomers, composed of 70% Bis-GMA and 30% TEGDMA by weight. Fillers were different among the groups. Glass, leucite ceramic and lithium disilicate were prepared as different filler types. All three groups contained 73% wt filler. Comphorquinone and amines were chosen as photo initiator system. Post curing was done for all groups. Diametral tensile strength (DTS, flexural strength and flexural modulus were measured and compared among groups. Data were analyzed with SPSS package using one-way ANOVA test with P<0.05 as the limit of significance. Results: The results showed that the stronger ceramic fillers have positive effect on the flexural strength. Ceramic fillers increased the flexural strength significantly. No significant differences could be determined in DTS among the groups. Flexural modulus can be affected and increased by using ceramic fillers. Conclusion: Flexural strength is one of the most significant properties of restorative dental materials. The higher flexural strength and flexural modulus can be achieved by stronger ceramic fillers. Any further investigation in this field would be beneficial in the development of restorative dental materials.

  3. Influence of Nanosilica Filler Content in LDPE Composites on Partial Discharge Characteristics

    Institute of Scientific and Technical Information of China (English)

    Z. Abdul-Malek; A.M. Azzin; Y.Z. Ariel; Aulia; K.Y. Lau; M. Jaafar

    2011-01-01

    Partial discharges (PDs) due to artificial void in samples of LDPE nanocomposite sheet have been investiga- ted in this work. PDs may cause the degradation of insulating materials and may affect the lifetime of high-voltage ap- paratus. An experimental work using sphere ball-plane electrode system (CIGRE Method II) and a 1.0 mm LDPE composite sheet was carried out. Different weight percentages of nanosilica (0%, 2%, 4%, 6% and 8%) were used. PD experimental results, such as PD magnitude and PD number (both PD pulse polarities), as functions of the ap- plied stress duration at a specified applied voltage were compared. The surface morphology of specimens was also presented and this conforms to the PD findings. The experimental results show that the PD characteristics of the LDPE generally improve with the introduction of nanosilica, the composite with the highest content of filler, namely the 8% (wt) nanosilica sample has the least partial discharge activities.

  4. Coupling effects of void size and void shape on the growth of prolate ellipsoidal microvoid

    Institute of Scientific and Technical Information of China (English)

    Minsheng Huang; Zhenhuan Li; Cheng Wang

    2005-01-01

    The combined effects of void size and void shape on the void growth are studied by using the classical spectrum method. An infinite solid containing an isolated prolate spheroidal void is considered to depict the void shape effect and the Fleck-Hutchinson phenomenological strain gradient plasticity theory is employed to capture the size effects. It is found that the combined effects of void size and void shape are mainly controlled by the remote stress triaxiality. Based on this, a new size-dependent void growth model similar to the Rice-Tracey model is proposed and an important conclusion about the size-dependent void growth is drawn: the growth rate of the void with radius smaller than a critical radius rc may be ignored. It is interesting that rc is a material constant independent of the initial void shape and the remote stress triaxiality.

  5. 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...... of the created air voids. The results indicate the presence of void clusters. To identify the individual voids, special computational approaches are needed. The addition of SAP results in a dominant peak in two of the three air void distributions. Based on the position (void diameter) of the peak, it is possible...

  6. 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...... of the created air voids. The results indicate the presence of void clusters. To identify the individual voids, special computational approaches are needed. The addition of SAP results in a dominant peak in two of the three air void distributions. Based on the position (void diameter) of the peak, it is possible...

  7. Silica-filled elastomers: polymer chain and filler characterization by a SANS-SAXS approach

    Energy Technology Data Exchange (ETDEWEB)

    Botti, A.; Pyckhout-Hintzen, W.; Richter, D. [IFF-Forschungszentrum Juelich, 52425 Juelich (Germany); Urban, V. [ESRF, BP220, 38043 Grenoble Cedex (France); IPNS, Argonne 60439-4814 (United States); Kohlbrecher, J. [PSI, 5232 Villigen (Switzerland); Straube, E. [University of Halle, FB Physik, 06099 Halle (Germany)

    2002-07-01

    A study of composites based upon commercially available silica fillers and networks of blends of protonated and deuterated anionically prepared polyisoprene is presented. The extraction of the single chain structure factor for SANS in the polymeric soft phase in isotropic and deformed state has been performed for the first time. The quasi three-component system could not be compositionally matched due to the internal structures of the activated fillers. For this, a parallel SAXS investigation provided the neccessary information on the filler structure which was lacking in the SANS analysis. Whereas mechanically clear reinforcement at low strains and filler-networking can be observed, the microscopic characterization of the chain deformation in the framework of the network tube model agrees with the estimates for hydrodynamic reinforcement of fractal fillers. (orig.)

  8. Silica-filled elastomers polymer chain and filler characterization by a SANS-SAXS approach

    CERN Document Server

    Botti, A; Richter, D; Urban, V; Ipns, A 6 4; Kohlbrecher, J; Straube, E

    2002-01-01

    A study of composites based upon commercially available silica fillers and networks of blends of protonated and deuterated anionically prepared polyisoprene is presented. The extraction of the single chain structure factor for SANS in the polymeric soft phase in isotropic and deformed state has been performed for the first time. The quasi three-component system could not be compositionally matched due to the internal structures of the activated fillers. For this, a parallel SAXS investigation provided the neccessary information on the filler structure which was lacking in the SANS analysis. Whereas mechanically clear reinforcement at low strains and filler-networking can be observed, the microscopic characterization of the chain deformation in the framework of the network tube model agrees with the estimates for hydrodynamic reinforcement of fractal fillers. (orig.)

  9. APPLICATION OF FILLERS IN CELLULOSIC PAPER BY SURFACE FILLING: AN INTERESTING ALTERNATIVE OR SUPPLEMENT TO WET-END ADDITION

    Directory of Open Access Journals (Sweden)

    Jing Shen,

    2012-01-01

    Full Text Available The application of fillers at the surface of cellulosic paper is an interesting and industrially-commercialized but not very well-known concept, in which the filler particles are essentially added to the voids of the fibrous matrixes. This so-called “surface filling” can be achieved by the use of fillers together with a polymer solution via film press or size press, an approach that is distinct from both wet-end filling and conventional coating of paper. As an easily practicable process, surface filling has some advantages over direct wet-end addition of fillers, such as minimizing the adverse effects of filler addition on paper strength. Efficient surface filling is somewhat dependent on the specific characteristics of both fillers and fibrous matrixes. Surface filling may provide interesting possibilities for the papermaking discipline; for example, it would open the door to maximizing the cost-effectiveness of paper mills, and efficiently adding new functionalities to cellulosic paper. From both practical and fundamental points of view, systematic exploration and understanding of surface filling of cellulosic paper would be of great significance to the papermaking industry.

  10. 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...

  11. Use of bottom ash from thermal power plant and lime as filler in bituminous mixtures

    Directory of Open Access Journals (Sweden)

    López-López, E.

    2015-06-01

    Full Text Available This study focuses on the characterization of bottom ash (PCC-BA and determining the mechanical characteristics of hot mix asphalt (HMA using PCC-BA and hydrated lime (HL as filler. Physical and chemical characterization of the bottom ash was carried out to evaluate its eventual reutilization as filler substitute. The materials tested in this study were made using 0%, 25%, 50%, 70% and 100% of PCC-BA combined with HL. HMA mixes were evaluated in terms of their engineering properties, namely: air voids in the mixes, water sensitivity, stiffness modulus, performance in wheel tracking test and fatigue resistance. The results obtained indicate that HMA mixes with a filler blend of 70% PCC-BA and 30% HL fulfil European standards and are suitable for light traffic or small infrastructures.Este estudio se centra en la caracterización de las cenizas de fondo (PCC-BA y la determinación de las características mecánicas de mezclas bituminosas en caliente (HMA, utilizando cenizas de fondo y la cal hidratada (HL como filler. Se realizó la caracterización física y química de las cenizas de fondo para evaluar su empleo como sustituto de filler. Las mezclas ensayadas en este estudio se realizaron utilizando 0%, 25%, 50%, 70% y 100% de cenizas de fondo combinadas con cal hidratada. Se evaluaron propiedades ingenieriles de las mezclas bituminosas, tales como los huecos de aire en las mezclas, la sensibilidad al agua, el módulo de rigidez, el ensayo de pista y la resistencia a la fatiga. Los resultados obtenidos indican que las mezclas bituminosas fabricadas con una combinación de filler del 70% de cenizas de fondo y el 30% cal hidratada, cumplen con las normas europeas y son adecuados para su aplicación con tráficos ligeros o en pequeñas infraestructuras.

  12. 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.

  13. Elucidation of filler-to-filler and filler-to-rubber interactions in silica-reinforced natural rubber by TEM Network Visualization

    NARCIS (Netherlands)

    Sarkawi, S.S.; Dierkes, W.K.; Noordermeer, J.W.M.

    2014-01-01

    Filler-to-rubber interaction is a key parameter in the reinforcement of rubber. This paper presents an investigation into filler-to-filler and filler-to-rubber interactions in silica-reinforced natural rubber (NR) in the presence and absence of a silane coupling agent. Using a special network visual

  14. 7 CFR 58.914 - Fillers.

    Science.gov (United States)

    2010-01-01

    ... gravity and vacuum type fillers shall be of sanitary design and all product contact surfaces, if metal... Standards for Plastic, and Rubber and Rubber-Like Materials. Fillers shall be designed so that they in no... MARKETING ACT OF 1946 AND THE EGG PRODUCTS INSPECTION ACT (CONTINUED) GRADING AND INSPECTION,...

  15. Adverse reactions to injectable soft tissue fillers

    DEFF Research Database (Denmark)

    Requena, Luis; Requena, Celia; Christensen, Lise

    2011-01-01

    In recent years, injections with filler agents are often used for wrinkle-treatment and soft tissue augmentation by dermatologists and plastic surgeons. Unfortunately, the ideal filler has not yet been discovered and all of them may induce adverse reactions. Quickly biodegradable or resorbable...

  16. Self Compacting Concrete with Chalk Filler

    DEFF Research Database (Denmark)

    Sørensen, Eigil V.

    2007-01-01

    at 28 days from about 35 MPa down to about 13 MPa. The cementing efficiency factor of the chalk filler was found to be in the range 0.21 - 0.42. The chalk filler performed equally well with a grey and a white cement; the latter opens the possibility to produce white SCC more cost effectively....

  17. Rheology of cement mixtures with dolomite filler

    Directory of Open Access Journals (Sweden)

    Martínez de la Cuesta, P. J.

    2000-06-01

    Full Text Available This experimental program has studied the behavior of fresh paste made up from cements mixed with dolomite filler. Through prior experiments the starting point is obtained for the designs 22 and 23 factorials. With these designs the governing equations are established that influence the specific surface of the filler, the filler percentage and the ratio water/(cement + filler, used as objective functions: test probe penetration, flow on table and shear stress in viscometer. Also the type of rheological conduct is determined and the influence over initial and final setting is observed.

    Este programa experimental estudia el comportamiento de las pastas frescas fabricadas a partir de cementos mezclados con filler dolomítico. En los experimentos previos se obtiene el punto central para los diseños 22 y 23 factoriales. Con estos diseños se establecen las ecuaciones que rigen la influencia de la superficie específica del filler, el porcentaje de filler y la relación agua/(cemento + filler, utilizando como funciones objetivos la penetración de sonda, la mesa de sacudidas y la tensión de corte en el viscosímetro. También se determina el tipo de conducta reológica y la influencia sobre el principio y fin de fraguado.

  18. 7 CFR 58.514 - Container fillers.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Container fillers. 58.514 Section 58.514 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards....514 Container fillers. Shall comply with the 3-A Sanitary Standards for Equipment for Packaging...

  19. The life and death of cosmic voids

    CERN Document Server

    Sutter, P M; Falck, Bridget; Onions, Julian; Hamaus, Nico; Knebe, Alexander; Srisawat, Chaichalit; Schneider, Aurel

    2014-01-01

    We investigate the formation, growth, merger history, movement, and destruction of cosmic voids detected via the watershed transform in a cosmological N-body dark matter {\\Lambda}CDM simulation. By adapting a method used to construct halo merger trees, we are able to trace individual voids back to their initial appearance and record the merging and evolution of their progenitors at high redshift. For the scales of void sizes captured in our simulation, we find that the void formation rate peaks at scale factor 0.3, which coincides with a growth in the void hierarchy and the emergence of dark energy. Voids of all sizes appear at all scale factors, though the median initial void size decreases with time. When voids become detectable they have nearly their present-day volumes. Almost all voids have relatively stable growth rates and suffer only infrequent minor mergers. Dissolution of a void via merging is very rare. Instead, most voids maintain their distinct identity as annexed subvoids of a larger parent. The...

  20. 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...... strain gradient plasticity models is implemented in a finite element program, which is used to study void growth numerically. The results based on the two models are compared. It is shown how gradient effects suppress void growth on the micron scale when compared to predictions based on conventional...... 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...

  1. The star formation activity in cosmic voids

    CERN Document Server

    Ricciardelli, Elena; Varela, Jesus; Quilis, Vicent

    2014-01-01

    Using a sample of cosmic voids identified in the Sloan Digital Sky Survey Data Release 7, we study the star formation activity of void galaxies. The properties of galaxies living in voids are compared with those of galaxies living in the void shells and with a control sample, representing the general galaxy population. Void galaxies appear to form stars more efficiently than shell galaxies and the control sample. This result can not be interpreted as a consequence of the bias towards low masses in underdense regions, as void galaxy subsamples with the same mass distribution as the control sample also show statistically different specific star formation rates. This highlights the fact that galaxy evolution in voids is slower with respect to the evolution of the general population. Nevertheless, when only the star forming galaxies are considered, we find that the star formation rate is insensitive to the environment, as the main sequence is remarkably constant in the three samples under consideration. This fact...

  2. Yolk shell nanocomposite particles as bioactive bone fillers and growth factor carriers.

    Science.gov (United States)

    Shi, Pujiang; Abbah, Sunny A; Chuah, Yon Jin; Li, Jun; Zhang, Yong; He, Pengfei; Wong, Hee Kit; Goh, James C H

    2017-09-20

    The efficient delivery of bioactive molecules via rationally designed nanoparticles is an important focus in regenerative medicine. The yolk shell nanocomposite particles described herein are composed of silk fibroin movable cores formed within voided calcium carbonate shells to load and control the release of labile cytokines. These particles are excellent carrier vehicles of potent molecules as they sustained the release of bioactive Bone Morphogenetic Protein 2 (BMP-2) for more than 28 days in vitro. Implantation into bone defects in rabbits corroborates the in vitro results and also reveals that upon contact with phosphate containing body fluids, implanted yolk shell particles agglomerate and transform into a filler that adapts to defect contour to further act as an absorbable hemostatic agent. Taken together, the fabrication of these yolk shell particle-based "bone fillers" could expand the horizon for the development of newer generations of advanced bioactive materials in tissue regeneration applications.

  3. 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.

  4. Large-scale clustering of cosmic voids

    Science.gov (United States)

    Chan, Kwan Chuen; Hamaus, Nico; Desjacques, Vincent

    2014-11-01

    We study the clustering of voids using N -body simulations and simple theoretical models. The excursion-set formalism describes fairly well the abundance of voids identified with the watershed algorithm, although the void formation threshold required is quite different from the spherical collapse value. The void cross bias bc is measured and its large-scale value is found to be consistent with the peak background split results. A simple fitting formula for bc is found. We model the void auto-power spectrum taking into account the void biasing and exclusion effect. A good fit to the simulation data is obtained for voids with radii ≳30 Mpc h-1 , especially when the void biasing model is extended to 1-loop order. However, the best-fit bias parameters do not agree well with the peak-background results. Being able to fit the void auto-power spectrum is particularly important not only because it is the direct observable in galaxy surveys, but also our method enables us to treat the bias parameters as nuisance parameters, which are sensitive to the techniques used to identify voids.

  5. The dark matter of galaxy voids

    CERN Document Server

    Sutter, P M; Wandelt, Benjamin D; Weinberg, David H; Warren, Michael S

    2013-01-01

    How do observed voids relate to the underlying dark matter distribution? To examine the spatial distribution of dark matter contained within voids identified in galaxy surveys, we apply Halo Occupation Distribution models representing sparsely and densely sampled galaxy surveys to a high-resolution N-body simulation. We compare these galaxy voids to voids found in the halo distribution, low-resolution dark matter, and high-resolution dark matter. We find that voids at all scales in densely sampled surveys - and medium- to large-scale voids in sparse surveys - trace the same underdensities as dark matter, but they are larger in radius by ~20%, they have somewhat shallower density profiles, and they have centers offset by ~0.4Rv rms. However, in void-to-void comparison we find that shape estimators are less robust to sampling, and the largest voids in sparsely sampled surveys suffer fragmentation at their edges. We find that voids in galaxy surveys always correspond to underdensities in the dark matter, though ...

  6. The dark matter of galaxy voids

    Science.gov (United States)

    Sutter, P. M.; Lavaux, Guilhem; Wandelt, Benjamin D.; Weinberg, David H.; Warren, Michael S.

    2014-03-01

    How do observed voids relate to the underlying dark matter distribution? To examine the spatial distribution of dark matter contained within voids identified in galaxy surveys, we apply Halo Occupation Distribution models representing sparsely and densely sampled galaxy surveys to a high-resolution N-body simulation. We compare these galaxy voids to voids found in the halo distribution, low-resolution dark matter and high-resolution dark matter. We find that voids at all scales in densely sampled surveys - and medium- to large-scale voids in sparse surveys - trace the same underdensities as dark matter, but they are larger in radius by ˜20 per cent, they have somewhat shallower density profiles and they have centres offset by ˜ 0.4Rv rms. However, in void-to-void comparison we find that shape estimators are less robust to sampling, and the largest voids in sparsely sampled surveys suffer fragmentation at their edges. We find that voids in galaxy surveys always correspond to underdensities in the dark matter, though the centres may be offset. When this offset is taken into account, we recover almost identical radial density profiles between galaxies and dark matter. All mock catalogues used in this work are available at http://www.cosmicvoids.net.

  7. Thermal Control Method for High-Current Wire Bundles by Injecting a Thermally Conductive Filler

    Science.gov (United States)

    Rodriguez-Ruiz, Juan; Rowles, Russell; Greer, Greg

    2011-01-01

    A procedure was developed to inject thermal filler material (a paste-like substance) inside the power wire bundle coming from solar arrays. This substance fills in voids between wires, which enhances the heat path and reduces wire temperature. This leads to a reduced amount of heat generated. This technique is especially helpful for current and future generation high-power spacecraft (1 kW or more), because the heat generated by the power wires is significant enough to cause unacceptable overheating to critical components that are in close contact with the bundle.

  8. Avoid a Void: The Eradication of Null Dereferencing

    Science.gov (United States)

    Meyer, Bertrand; Kogtenkov, Alexander; Stapf, Emmanuel

    All object-oriented programs, but also those in C or Pascal as soon as they use pointers, are subject to the risk of run-time crash due to "null pointer dereferencing". Until recently this was the case even in statically typed languages. Tony Hoare has called this problem his "billion-dollar mistake". In the type system of ISO-standard Eiffel, the risk no longer exists: void safety (the absence of null pointer dereferencing) has become a property guaranteed by the type system and enforced by the compiler. The mechanism is fully implemented and major libraries and applications have been made void-safe. This presentation describes the principles of Eiffel's void safety, their implementation and the lessons gained.

  9. New Manufacturing Method for Paper Filler and Fiber Material

    Energy Technology Data Exchange (ETDEWEB)

    Doelle, Klaus [SUNY College of Environmental Science and Forestry

    2013-08-25

    . If the new technology could be implemented for bleaching process a total annual estimated energy savings potential of 64 trillion buts or 11 million barrel of oil equivalent (BOE) equal to 3% of the paper industries energy demand could be realized. This could lead to a increase of renewable energy usage from 56% to close to 60% for the industry. CO{sub 2} emissions could be lowered by over 7.4 million tons annually. It is estimated that an installed system could also yield a 75 to 100% return of investment (ROI) rate for the capital equipment that need to be installed for the fiber filler composite manufacturing process.

  10. Geometric and Chemical Composition Effects on Healing Kinetics of Voids in Mg-bearing Al Alloys

    Science.gov (United States)

    Song, Miao; Du, Kui; Wang, Chunyang; Wen, Shengping; Huang, Hui; Nie, Zuoren; Ye, Hengqiang

    2016-05-01

    The healing kinetics of nanometer-scale voids in Al-Mg-Er and Al-Mg-Zn-Er alloy systems were investigated with a combination of in situ transmission electron microscopy and electron tomography at different temperatures. Mg was observed completely healing the voids, which were then rejuvenated to the alloy composition with further aging, in the Al-Mg-Er alloy. On the contrary, Mg51Zn20 intermetallic compound was formed in voids in the Al-Mg-Zn-Er alloy, which leads to complete filling of the voids but not rejuvenation for the material. For voids with different geometrical aspects, different evolution processes were observed, which are related to the competition between bulk and surface diffusion of the alloys. For voids with a large size difference in their two ends, a viscous flow of surface atoms can be directly observed with in situ electron microscopy, when the size of one end becomes less than tens of nanometers.

  11. Effect of Geopolymer filler in Glass Reinforced Epoxy (GRE) Pipe for Piping Application: Mechanical Properties

    Science.gov (United States)

    Firdaus Abu Hashim, Mohammad; Bakri Abdullah, Mohd Mustafa Al; Mohd Ruzaidi Ghazali, Che; Hussin, Kamarudin; Binhussain, Mohammed

    2016-06-01

    The present work is aimed to carry out the effect of geopolymer material which is fly ash as filler in the glass reinforced epoxy pipe on the micro structure of fly ash geopolymer, compression properties, and bulk density using the filament winding method. Conventional glass reinforced epoxy pipes has its own disadvantages such as high corrosion resistance at acidic environment and low strength which can be replaced by the composite pipes. Geopolymer is a type of amorphous alumino-silicate and can be synthesized by geopolymerization process. A series of glass reinforced epoxy pipe and glass reinforced epoxy pipe filled with 10 - 40 weight percentage geopolymer filler which is fly ash with 4 Molarity were prepared. Morphology of the raw material fly ash and fly ash based-geopolymer surface was characterized using scanning electron microscopy. It was found that the additions of fly ash at the beginning with 10 wt% are showing higher compressive strength than glass reinforced epoxy pipe without fly ash geopolymer filler. The compressive test of these series of samples was determined using Instron Universal Testing under compression mode. It was found that compressive strength for samples fly ash based-geopolymer filler are higher as compared to glass reinforced epoxy pipe without geopolymer filler. However, the compressive strength of glass reinforced epoxy pipe with fly ash geopolymer filler continues to decline when added to 20 wt% - 40 wt% of geopolymer filler loading. The results showed that the mixing of geopolymer materials in epoxy system can be obtained in this study.

  12. [Development of remote wireless mobile voiding diary and a report of its objective voiding in 20 young people].

    Science.gov (United States)

    Guan, Zhi-chen; Wei, Ben-lin; Meng, Zuo-wei

    2010-08-18

    To find out the data of the micturitions in healthy young people with the remote & mobile voiding diary monitoring system. Twenty healthy young people were studied and ten of them were female. The ages ranged from 22 to 35 years (the mean age: 27.4 years). The females were 22-33 years old (the mean age: 26.4 years ) and the males 24-35 years old (the mean age: 28.4 years). With the remote & mobile voiding diary monitoring system, their voiding information was collected. Through bluetooth, the voiding information was sent to the patient's intelligent cell phone from the collector, then stored directly by intelligent cell phone and wirelessly transmitted to the workstation in the hospital. All of them completed the voiding diaries for 7 days and the data were analyzed. The average micturition of the young healthy people was 5.6 times (3.4-7.4) per 24 hours,in which 5.3 (3.4-7.3) times were in the daytime and 0.3 (0-1.3)times in the night. The functional voiding volume was 318 mL (66-642 mL). The mean voiding volume in 24 hours was 1 724 mL (1152-2 415 mL), in which 1 289 mL (786-2 039 mL) was in the daytime and 435 mL (292-805 mL) in the night. The mean drinking volume was 1 022 mL (453-1 721 mL) in the daytime and 7 mL (0-43 mL) in the night. The nocturia index (Ni) was 1.03, the nocturnal polyuria index (NPi) 26%, and the nocturnal bladder capacity index (NBCi) 0.27. The remote & mobile voiding diary monitoring system can help us get the objective voiding information from young health people for the first time. It is reliable, maneuverable and can be widely used in clinical diagnosis.

  13. Electrical conductivity modeling of multiple carbon fillers in liquid crystal polymer composites for fuel cell bipolar plate applications

    Energy Technology Data Exchange (ETDEWEB)

    Barton, R.L.; Keith, J.M.; King, J.A. [Michigan Technological Univ., Houghton, MI (United States). Dept. of Chemical Engineering

    2008-08-15

    This study modelled the electrical conductivity of a single filler composite system using a general effective media (GEM) equation. The aim of the study was to investigate the use of synthetic graphite and carbon fiber in liquid crystal polymers for fuel cell bipolar plate applications. The polymer consisted of 73 mole per cent hydroxybenzoic acid and 27 mole per cent hydroxynaphthoic acid. Composites of various concentrations of single and multiple filler combinations were tested. A volumetric in-plane electrical conductivity test was conducted on all samples in order to measure voltage drop. A through-plane conductivity test was conducted to measure resistivity. The GEM equation was then used to model the conductivity data obtained during the tests. Results of the study showed that at 45 vol per cent, the electrical conductivity of the multiple filler composite was comparable to data obtained from single filler electrical conductivities. The electrical conductivity of the multiple filler composite at 60 per cent graphite and 10 per cent carbon fiber was comparable to the single filler carbon fiber composite, but lower than the single filler synthetic graphite composite. Results also showed that the GEM equation provided excellent agreement with results obtained during the experiments. It was concluded that the percolation threshold of the multiple filler composite was almost identical to the single carbon fiber filler, but lower than the single synthetic graphite composite. 35 refs., 3 tabs., 2 figs.

  14. The Beckoning Void in Moravagine

    Directory of Open Access Journals (Sweden)

    Stephen K. Bellstrom

    1979-01-01

    Full Text Available The Chapter «Mascha,» lying at the heart of Cendrars's Moravagine , contains within it a variety of images and themes suggestive of emptiness. The philosophy of nihilism is exemplified in the motivations and actions of the group of terrorists seeking to plunge Russia into revolutionary chaos. Mascha's anatomical orifice, symbolizing both a biological and a psychological fault, and the abortion of her child, paralleled by the abortion of the revolutionary ideal among her comrades, are also emblematic of the chapter's central void. Moreover, Cendrars builds the theme of hollowness by describing Moravagine with images of omission, such as «empan» (space or span, «absent,» and «étranger.» Moravagine's presence, in fact, characteristically causes an undercurrent of doubt and uncertainty about the nature of reality to become overt. It is this parodoxical presence which seems to cause the narrator (and consequently the narrative to «lose» a day at the most critical moment of the story. By plunging the reader into the narrator's lapsus memoriae , Cendrars aims at creating a feeling of the kind of mental and cosmic disorder for which Moravagine is the strategist and apologist. This technique of insufficiency is an active technique, even though it relies on the passive idea of removing explanation and connecting details. The reader is invited, or lured, into the central void of the novel and, faced with unresolvable dilemmas, becomes involved in the same disorder that was initially produced.

  15. Fracture resistance of rubbers with MWCNT, organoclay, silica and carbon black fillers as assessed by the J-integral: Effects of rubber type and filler concentration

    Directory of Open Access Journals (Sweden)

    T. Ricco

    2012-07-01

    Full Text Available The fracture resistance of different rubbers containing various nanofillers, such as multiwall carbon nanotube (MWCNT, organoclay, silica and carbon black (CB, was determined by the J-integral making use of the single edge notched tensile loaded (SEN-T single specimen approach. The elastomeric matrices were natural (NR, ethylene propylene diene (EPDM and hydrogenated nitrile rubbers (HNBR. Moreover, the strain softening (Payne effect of selected rubbers with 30 part per hundred rubber (phr filler content was also investigated by dynamic mechanical thermal analysis (DMTA in shear mode. DMTA results indicated that the Payne effect follows the ranking: MWCNT(fibrous > organoclay(platy > silica(spherical. J-resistance (JR curves were constructed by plotting the J value as a function of the crack tip opening displacement (CTOD*, monitored during loading. CTOD* = 0.1 mm was considered as crack initiation threshold and thus assigned to the critical value JIc. JIc increased with increasing filler loading, whereby MWCNT outperformed both silica and CB. On the other hand, JIc did not change with filler loading for the NR/organoclay systems that was traced to straininduced crystallization effect in NR. The tearing modulus (TJ also increased with increasing filler loading. The related increase strongly depended on both rubber and filler types. Nonetheless, the most prominent improvement in TJ among the fillers studied was noticed for the fibrous MWCNT.

  16. Universal density profile for cosmic voids.

    Science.gov (United States)

    Hamaus, Nico; Sutter, P M; Wandelt, Benjamin D

    2014-06-27

    We present a simple empirical function for the average density profile of cosmic voids, identified via the watershed technique in ΛCDM N-body simulations. This function is universal across void size and redshift, accurately describing a large radial range of scales around void centers with only two free parameters. In analogy to halo density profiles, these parameters describe the scale radius and the central density of voids. While we initially start with a more general four-parameter model, we find two of its parameters to be redundant, as they follow linear trends with the scale radius in two distinct regimes of the void sample, separated by its compensation scale. Assuming linear theory, we derive an analytic formula for the velocity profile of voids and find an excellent agreement with the numerical data as well. In our companion paper [Sutter et al., arXiv:1309.5087 [Mon. Not. R. Astron. Soc. (to be published)

  17. Air void structure and frost resistance

    DEFF Research Database (Denmark)

    Hasholt, Marianne Tange

    2014-01-01

    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......This article compiles results from 4 independent laboratory studies. In each study, the same type of concrete is tested at least 10 times, the air void structure being the only variable. For each concrete mix both air void analysis of the hardened concrete and a salt frost scaling test...

  18. Void Profile from Planck Lensing Potential Map

    Science.gov (United States)

    Chantavat, Teeraparb; Sawangwit, Utane; Wandelt, Benjamin D.

    2017-02-01

    We use the lensing potential map from Planck CMB lensing reconstruction analysis and the “Public Cosmic Void Catalog” to measure the stacked void lensing potential. We have made an attempt to fit the HSW void profile parameters from the stacked lensing potential. In this profile, four parameters are needed to describe the shape of voids with different characteristic radii R V . However, we have found that after reducing the background noise by subtracting the average background, there is a residue lensing power left in the data. The inclusion of the environment shifting parameter, {γ }V, is necessary to get a better fit to the data with the residue lensing power. We divide the voids into two redshift bins: cmass1 (0.45Digital Sky Survey voids reside in an underdense region.

  19. 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.

  20. Cosmetic Fillers: Perspectives on the Industry.

    Science.gov (United States)

    Basta, Steven L

    2015-11-01

    The cosmetic filler industry has evolved substantially over the last 30 years. The market is characterized by multiple fillers and a competitive dynamic among major aesthetics companies. Marketing in the United States and Europe has been different owing to regulatory constraints. Differences have led to more rapid growth in the European market. The US market has evolved owing to growth of major companies with multiple product portfolios and leverage in consumer promotion and aesthetics office marketing owing to scale. The evolution of the filler market will include new materials, injection techniques, and facilitation devices, and new areas of injection.

  1. Fillers for the improvement in acne scars

    Directory of Open Access Journals (Sweden)

    Wollina U

    2015-09-01

    Full Text Available Uwe Wollina,1 Alberto Goldman2 1Department of Dermatology and Allergology, Academic Teaching Hospital, Dresden-Friedrichstadt, Dresden, Germany; 2Clinica Goldman, Porto Alegre, Rio Grande do Sul, Brazil Abstract: Acne is a common inflammatory disease. Scarring is an unwanted end point of acne. Both atrophic and hypertrophic scar types occur. Soft-tissue augmentation aims to improve atrophic scars. In this review, we will focus on the use of dermal fillers for acne scar improvement. Therefore, various filler types are characterized, and available data on their use in acne scar improvement are analyzed. Keywords: acne, scars, dermal fillers, injection, extracellular matrix

  2. Alumina-clay nanoscale hybrid filler assembling in cross-linked polyethylene based nanocomposites: mechanics and thermal properties.

    Science.gov (United States)

    Jose, Josmin P; Thomas, Sabu

    2014-07-28

    Herein, investigation on XLPE-Al2O3-clay ternary hybrid systems of Al2O3 and clay in 1 : 1 and 2 : 1 ratios, binary systems of XLPE-clay and XLPE-Al2O3 nanocomposites, with special reference to the hybrid filler effect and the superior microstructural development in ternary systems is conducted. The ternary hybrid composite of Al2O3 and clay in a 1 : 1 ratio exhibits the highest tensile strength (100% increase) and Young's modulus (208% increase), followed by the Al2O3 : clay = 2 : 1 system. The interaction between alumina and clay altered the composite morphology, filler dispersion and gave rise to a unique filler architecture leading to a substantial boost up in mechanics compared to predictions based on the idealized filler morphology. Experimentally observed much higher mechanics compared to theoretical predictions confirmed that the dramatic improvement in mechanics is the outcome of the positive hybrid effect and a second factor of synergism, i.e. filler-filler networks. Morphological control of the hybrid filler network is realized by adjusting the ratio between different fillers. For the Al2O3 : clay = 2 : 1 system, the microstructural limitation of dispersion due to the steric effect of alumina clusters shifts the properties to the negative hybrid effect region.

  3. Voids in cosmological simulations over cosmic time

    Science.gov (United States)

    Wojtak, Radosław; Powell, Devon; Abel, Tom

    2016-06-01

    We study evolution of voids in cosmological simulations using a new method for tracing voids over cosmic time. The method is based on tracking watershed basins (contiguous regions around density minima) of well-developed voids at low redshift, on a regular grid of density field. It enables us to construct a robust and continuous mapping between voids at different redshifts, from initial conditions to the present time. We discuss how the new approach eliminates strong spurious effects of numerical origin when voids' evolution is traced by matching voids between successive snapshots (by analogy to halo merger trees). We apply the new method to a cosmological simulation of a standard Λ-cold-dark-matter cosmological model and study evolution of basic properties of typical voids (with effective radii 6 h-1 Mpc < Rv < 20 h-1 Mpc at redshift z = 0) such as volumes, shapes, matter density distributions and relative alignments. The final voids at low redshifts appear to retain a significant part of the configuration acquired in initial conditions. Shapes of voids evolve in a collective way which barely modifies the overall distribution of the axial ratios. The evolution appears to have a weak impact on mutual alignments of voids implying that the present state is in large part set up by the primordial density field. We present evolution of dark matter density profiles computed on isodensity surfaces which comply with the actual shapes of voids. Unlike spherical density profiles, this approach enables us to demonstrate development of theoretically predicted bucket-like shape of the final density profiles indicating a wide flat core and a sharp transition to high-density void walls.

  4. Whisker-reinforced dental core buildup composites: effect of filler level on mechanical properties.

    Science.gov (United States)

    Xu, H H; Smith, D T; Schumacher, G E; Eichmiller, F C

    2000-12-15

    The strength and toughness of dental core buildup composites in large stress-bearing restorations need to be improved to reduce the incidence of fracture due to stresses from chewing and clenching. The aims of the present study were to develop novel core buildup composites reinforced with ceramic whiskers, to examine the effect of filler level, and to investigate the reinforcement mechanisms. Silica particles were fused onto the whiskers to facilitate silanization and to roughen the whisker surface for improved retention in the matrix. Filler level was varied from 0 to 70%. Flexural strength, compressive strength, and fracture toughness of the composites were measured. A nano-indentation system was used to measure elastic modulus and hardness. Scanning electron microscopy (SEM) was used to examine the fracture surfaces of specimens. Whisker filler level had significant effects on composite properties. The flexural strength in MPa (mean +/- SD; n = 6) increased from (95+/-15) for the unfilled resin to (193+/- 8) for the composite with 50% filler level, then slightly decreased to (176+/-12) at 70% filler level. The compressive strength increased from (149+/-33) for the unfilled resin to (282+/-48) at 10% filler level, and remained equivalent from 10 to 70% filler level. Both the modulus and hardness increased monotonically with filler level. In conclusion, silica particle-fused ceramic single-crystalline whiskers significantly reinforced dental core buildup composites. The reinforcement mechanisms appeared to be crack deflection and bridging by the whiskers. Whisker filler level had significant effects on the flexural strength, compressive strength, elastic modulus, and hardness of composites.

  5. Cosmological Black Holes as Seeds of Voids in Galaxy Distribution

    CERN Document Server

    Capozziello, S; Stornaiolo, C; Capozziello, Salvatore; Funaro, Maria; Stornaiolo, Cosimo

    2004-01-01

    Deep surveys indicate a bubbly structure of cosmological large scale which should be the result of evolution of primordial density perturbations. Several models have been proposed to explain origin and dynamics of such features but, till now, no exhaustive and fully consistent theory has been found. We discuss a model where cosmological black holes, deriving from primordial perturbations, are the seeds for large-scale-structure voids. We give details of dynamics and accretion of the system voids-cosmological black holes from the epochs $(z\\simeq10^{3})$ till now finding that void of $40h^{-1}Mpc$ of diameter and under-density of -0.9 will fits the observations without conflicting with the homogeneity and isotropy of cosmic microwave background radiation.

  6. New Manufacturing Method for Paper filler and Fiber Material

    Energy Technology Data Exchange (ETDEWEB)

    Doelle, Klaus

    2011-11-22

    The study compares commercial available filler products with a new developed “Hybrid Fiber Filler Composite Material” and how main structural, optical and strength properties are affected by increasing the filler content of at least 5% over commercial values. The study consists of: (i) an overview of paper filler materials used in the paper production process, (ii) discusses the manufacturing technology of lime based filler materials for paper applications, (iii) gives an overview of new emerging paper filler technologies, (iv) discusses a filler evaluation of commercial available digital printing paper products, (v) reports from a detailed handsheet study and 12” pilot plant paper machine trial runs with the new Hybrid Fiber Filler Composite Material, and (vi) evaluates and compares commercial filler products and the new Hybrid Fiber Filler Composite Material with a life cycle analyses that explains manufacturing, economic and environmental benefits as they are applied to uncoated digital printing papers.

  7. Thermal pretreatment of silica composite filler materials

    OpenAIRE

    Wan, Quan; Ramsey, Christopher; Baran, George

    2010-01-01

    Three different silica filler materials were thermally treated in order to effect dehydration, dehydroxylation, and rehydroxylation. Samples were characterized by thermogravimetry (TG), pycnometry, elemental analysis, and scanning electron microscopy (SEM). For all fillers, our results indicate incremental removal of silanol groups at higher heating temperatures and irreversible dehydroxylation at over 673 K. To remove the organic content and maintain adequate silanol density for subsequent s...

  8. 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...

  9. 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

  10. 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

  11. Voids in cosmological simulations over cosmic time

    CERN Document Server

    Wojtak, Radosław; Abel, Tom

    2016-01-01

    We study evolution of voids in cosmological simulations using a new method for tracing voids over cosmic time. The method is based on tracking watershed basins (contiguous regions around density minima) of well developed voids at low redshift, on a regular grid of density field. It enables us to construct a robust and continuous mapping between voids at different redshifts, from initial conditions to the present time. We discuss how the new approach eliminates strong spurious effects of numerical origin when voids evolution is traced by matching voids between successive snapshots (by analogy to halo merger trees). We apply the new method to a cosmological simulation of a standard LambdaCDM cosmological model and study evolution of basic properties of typical voids (with effective radii between 6Mpc/h and 20Mpc/h at redshift z=0) such as volumes, shapes, matter density distributions and relative alignments. The final voids at low redshifts appear to retain a significant part of the configuration acquired in in...

  12. A new geometrical approach to void statistics

    CERN Document Server

    Werner, M C

    2014-01-01

    Modelling cosmic voids as spheres in Euclidean space, the notion of a de-Sitter configuration space is introduced. It is shown that a uniform distribution over this configuration space yields a power-law approximating the void size distribution in an intermediate range of volumes, as well as an estimate for the fractal dimension of the large scale structure.

  13. Tracing the gravitational potential using cosmic voids

    CERN Document Server

    Nadathur, Seshadri; Crittenden, Robert

    2016-01-01

    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 and the gravitational potential $\\Phi$. 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, $\\lambda_v$, 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 $\\Phi$ as a function of $\\lambda_v$ is found to hold, independent of the redshift and properties of t...

  14. Simulation of dust voids in complex plasmas

    NARCIS (Netherlands)

    W. J. Goedheer,; Land, V.

    2008-01-01

    In dusty radio-frequency (RF) discharges under micro-gravity conditions often a void is observed, a dust free region in the discharge center. This void is generated by the drag of the positive ions pulled out of the discharge by the electric field. We have developed a hydrodynamic model for dusty RF

  15. The Hierarchical Structure and Dynamics of Voids

    CERN Document Server

    Aragon-Calvo, M A

    2012-01-01

    Contrary to the common view voids have very complex internal structure and dynamics. Here we show how the hierarchy of structures in the density field inside voids is reflected by a similar hierarchy of structures in the velocity field. Voids defined by dense filaments and clusters can de described as simple expanding domains with coherent flows everywhere except at their boundaries. At scales smaller that the void radius the velocity field breaks into expanding sub-domains corresponding to sub- voids. These sub-domains break into even smaller sub-sub domains at smaller scales resulting in a nesting hierarchy of locally expanding domains. The ratio between the magnitude of the velocity field responsible for the expansion of the void and the velocity field defining the sub voids is approximately one order of magnitude. The small-scale components of the velocity field play a minor role in the shaping of the voids but they define the local dynamics directly affecting the processes of galaxy formation and evoluti...

  16. VIDE: The Void IDentification and Examination toolkit

    CERN Document Server

    Sutter, P M; Hamaus, Nico; Pisani, Alice; Wandelt, Benjamin D; Warren, Michael S; Villaescusa-Navarro, Francisco; Zivick, Paul; Mao, Qingqing; Thompson, Benjamin B

    2014-01-01

    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 greatly enhanced version of ZOBOV (Neyinck 2008) to calculate a Voronoi tessellation for estimating the density field and a watershed transform to construct voids. The watershed levels are used to place voids in a hierarchical tree. VIDE provides significant additional 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 outputs a summary of void properties in plain ASCII, and provides a Python API to perform many analysi...

  17. Braze welding of cobalt with a silver–copper filler

    Directory of Open Access Journals (Sweden)

    Everett M. Criss

    2015-01-01

    Full Text Available A new method of joining cobalt by braze-welding it with a silver–copper filler was developed in order to better understand the residual stresses in beryllium–aluminum/silicon weldments which are problematic to investigate because of the high toxicity of Be. The base and filler metals of this new welding system were selected to replicate the physical properties, crystal structures, and chemical behavior of the Be–AlSi welds. Welding parameters of this surrogate Co–AgCu system were determined by experimentation combining 4-point bending tests and microscopy. Final welds are 5 pass manual TIG (tungsten inert gas, with He top gas and Ar back gas. Control of the welding process produces welds with full penetration melting of the cobalt base. Microscopy indicates that cracking is minimal, and not through thickness, whereas 4-point bending shows failure is not by base-filler delamination. These welds improve upon the original Be–AlSi welds, which do not possess full penetration, and have considerable porosity. We propose that utilization of our welding methods will increase the strength of the Be–AlSi weldments. The specialized welding techniques developed for this study may be applicable not only for the parent Be–AlSi welds, but to braze welds and welds utilizing brittle materials in general. This concept of surrogacy may prove useful in the study of many different types of exotic welds.

  18. Plasma-modified graphene nanoplatelets and multiwalled carbon nanotubes as fillers for advanced rubber composites

    Science.gov (United States)

    Sicinski, M.; Gozdek, T.; Bielinski, D. M.; Szymanowski, H.; Kleczewska, J.; Piatkowska, A.

    2015-07-01

    In modern rubber industry, there still is a room for new fillers, which can improve the mechanical properties of the composites, or introduce a new function to the material. Modern fillers like carbon nanotubes or graphene nanoplatelets (GnP), are increasingly applied in advanced polymer composites technology. However, it might be hard to obtain a well dispersed system for such systems. The polymer matrix often exhibits higher surface free energy (SFE) level with the filler, which can cause problems with polymer-filler interphase adhesion. Filler particles are not wet properly by the polymer, and thus are easier to agglomerate. As a consequence, improvement in the mechanical properties is lower than expected. In this work, multi-walled carbon nanotubes (MWCNT) and GnP surface were modified with low-temperature plasma. Attempts were made to graft some functionalizing species on plasma-activated filler surface. The analysis of virgin and modified fillers’ SFE was carried out. MWCNT and GnP rubber composites were produced, and ultimately, their morphology and mechanical properties were studied.

  19. Effect on mechanical properties of glass reinforced epoxy (GRE) pipe filled with different geopolymer filler molarity for piping application

    Science.gov (United States)

    Hashim, M. F. Abu; Abdullah, M. M. A.; Ghazali, C. M. R.; Hussin, K.; Binhussain, M.

    2017-04-01

    This study investigated the use of a novel white clay geopolymer as a filler to produce high strength glass reinforced epoxy pipe. It was found that using white clay geopolymer as filler gives better compressive strength to the glass reinforced epoxy pipe. The disadvantages of current glass reinforced epoxy pipes such low compressive strength which can be replaced by the composite pipes. Geopolymerization is an innovative technology that can transform several aluminosilicate materials into useful products called geopolymers or inorganic polymers. A series of glass reinforced epoxy pipe and glass reinforced epoxy pipe filled with 10 - 40 weight percentages white clay geopolymer filler with 4 Molarity and 8 Molarity were prepared. Morphology of white clay geopolymer filler surface was indicates using scanning electron microscopy. The additions of white clay geopolymer filler for both 4 Molarity and 8 Molarity show higher compressive strength than glass reinforced epoxy pipe without any geopolymer filler. The compressive test of these epoxy geopolymer pipe samples was determined using Instron Universal Testing under compression mode. Nonetheless, the compressive strength of glass reinforced epoxy pipe with white clay geopolymer filler continues to drop when added to 40 wt% of the geopolymer filler loading for both 4 Molarity and 8 Molarity. These outcomes showed that the mixing of geopolymer materials in epoxy system can be attained in this research.

  20. Cosmic voids and void lensing in the Dark Energy Survey Science Verification data

    Energy Technology Data Exchange (ETDEWEB)

    Sánchez, C.; Clampitt, J.; Kovacs, A.; Jain, B.; García-Bellido, J.; Nadathur, S.; Gruen, D.; Hamaus, N.; Huterer, D.; Vielzeuf, P.; Amara, A.; Bonnett, C.; DeRose, J.; Hartley, W. G.; Jarvis, M.; Lahav, O.; Miquel, R.; Rozo, E.; Rykoff, E. S.; Sheldon, E.; Wechsler, R. H.; Zuntz, J.; Abbott, T. M. C.; Abdalla, F. B.; Annis, J.; Benoit-Lévy, A.; Bernstein, G. M.; Bernstein, R. A.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Rosell, A. Carnero; Kind, M. Carrasco; Carretero, J.; Crocce, M.; Cunha, C. E.; D' Andrea, C. B.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Evrard, A. E.; Neto, A. Fausti; Flaugher, B.; Fosalba, P.; Frieman, J.; Gaztanaga, E.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; James, D. J.; Krause, E.; Kuehn, K.; Lima, M.; Maia, M. A. G.; Marshall, J. L.; Melchior, P.; Plazas, A. A.; Reil, K.; Romer, A. K.; Sanchez, E.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Tarle, G.; Thomas, D.; Walker, A. R.; Weller, J.

    2016-10-26

    Galaxies and their dark matter halos populate a complicated filamentary network around large, nearly empty regions known as cosmic voids. Cosmic voids are usually identified in spectroscopic galaxy surveys, where 3D information about the large-scale structure of the Universe is available. Although an increasing amount of photometric data is being produced, its potential for void studies is limited since photometric redshifts induce line-of-sight position errors of $\\sim50$ Mpc/$h$ or more that can render many voids undetectable. In this paper we present a new void finder designed for photometric surveys, validate it using simulations, and apply it to the high-quality photo-$z$ redMaGiC galaxy sample of the Dark Energy Survey Science Verification (DES-SV) data. The algorithm works by projecting galaxies into 2D slices and finding voids in the smoothed 2D galaxy density field of the slice. Fixing the line-of-sight size of the slices to be at least twice the photo-$z$ scatter, the number of voids found in these projected slices of simulated spectroscopic and photometric galaxy catalogs is within 20% for all transverse void sizes, and indistinguishable for the largest voids of radius $\\sim 70$ Mpc/$h$ and larger. The positions, radii, and projected galaxy profiles of photometric voids also accurately match the spectroscopic void sample. Applying the algorithm to the DES-SV data in the redshift range $0.2voids with comoving radii spanning the range 18-120 Mpc/$h$, and carry out a stacked weak lensing measurement. With a significance of $4.4\\sigma$, the lensing measurement confirms the voids are truly underdense in the matter field and hence not a product of Poisson noise, tracer density effects or systematics in the data. It also demonstrates, for the first time in real data, the viability of void lensing studies in photometric surveys.

  1. Modelling Void Abundance in Modified Gravity

    CERN Document Server

    Voivodic, Rodrigo; Llinares, Claudio; Mota, David F

    2016-01-01

    We use a spherical model and an extended excursion set formalism with drifting diffusive barriers to predict the abundance of cosmic voids in the context of general relativity as well as f(R) and symmetron models of modified gravity. We detect spherical voids from a suite of N-body simulations of these gravity theories and compare the measured void abundance to theory predictions. We find that our model correctly describes the abundance of both dark matter and galaxy voids, providing a better fit than previous proposals in the literature based on static barriers. We use the simulation abundance results to fit for the abundance model free parameters as a function of modified gravity parameters, and show that counts of dark matter voids can provide interesting constraints on modified gravity. For galaxy voids, more closely related to optical observations, we find that constraining modified gravity from void abundance alone may be significantly more challenging. In the context of current and upcoming galaxy surv...

  2. Redshift-space distortions around voids

    CERN Document Server

    Cai, Yan-Chuan; Peacock, John A; Padilla, Nelson

    2016-01-01

    We have derived estimators for the linear growth rate of density fluctuations using the cross-correlation function of voids and haloes in redshift space, both directly and in Fourier form. In linear theory, this cross-correlation 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 in N-body simulations; small-scale random velocities are unimportant at these radii, only tending to cause small and often negligible elongation of the redshift-space cross-correlation function near its origin. By extracting the monopole and quadrupole from the cross-correlation function, we measure the linear growth rate without prior knowledge of the void profile or velocity dispersion. We recover the linear growth parameter $\\beta$ to 9% precision from an effective volume of 3(Gpc/h)^3 using voids with radius greater than 25Mpc/h. Smaller voids are predominantly sub-voids, which may be more sensitive to the random velocity dispersion; the...

  3. Experimental facility and void fraction calibration methods for impedance probes

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Fernando L. de; Rocha, Marcelo S., E-mail: floliveira@ipen.br, E-mail: msrocha@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    An experimental facility was designed and constructed with aims of to calibrate a capacitance probe for gas-liquid flow void fraction measurements. The facility is composed of a metallic hack with a vertical 2,300 mm high glass tube with 38 mm ID with stagnant water and compressed air bubbling system simulating the gas phase (vapor). At the lower part, a mixing section with a porous media element releases the air bubbles into the water, and the compressed air flow is measured by two calibrated rotameters. At the upper part a stagnant water tank separates the liquid and gas. Two pressure taps are located near the lower and upper sides of the glass tube for pressure difference measurement. The pressure difference is used for low void fraction values (0-15%) calibration methods, as described in the work. Two electrically controlled quick closing valves are installed between the porous media element and the upward separation tank for high void fraction values measurement (15-50%) used to calibrate the capacitance probe. The experimental facility design, construction, capacitance probe calibration methods and results, as well as flow pattern visualization, are presented. Finally, the capacitance probe will be installed on a natural circulation circuit mounted at the Nuclear Engineering Center (CEN/IPEN/CNEN-SP) for measurement of the instantaneous bulk void. Instantaneous signals generated by the capacitance probe will allow the determination of natural circulation loop global energy balance. (author)

  4. Compensation for air voids in photoacoustic computed tomography image reconstruction

    Science.gov (United States)

    Matthews, Thomas P.; Li, Lei; Wang, Lihong V.; Anastasio, Mark A.

    2016-03-01

    Most image reconstruction methods in photoacoustic computed tomography (PACT) assume that the acoustic properties of the object and the surrounding medium are homogeneous. This can lead to strong artifacts in the reconstructed images when there are significant variations in sound speed or density. Air voids represent a particular challenge due to the severity of the differences between the acoustic properties of air and water. In whole-body small animal imaging, the presence of air voids in the lungs, stomach, and gastrointestinal system can limit image quality over large regions of the object. Iterative reconstruction methods based on the photoacoustic wave equation can account for these acoustic variations, leading to improved resolution, improved contrast, and a reduction in the number of imaging artifacts. However, the strong acoustic heterogeneities can lead to instability or errors in the numerical wave solver. Here, the impact of air voids on PACT image reconstruction is investigated, and procedures for their compensation are proposed. The contributions of sound speed and density variations to the numerical stability of the wave solver are considered, and a novel approach for mitigating the impact of air voids while reducing the computational burden of image reconstruction is identified. These results are verified by application to an experimental phantom.

  5. 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.

  6. The darkness that shaped the void: dark energy and cosmic voids

    CERN Document Server

    Bos, E G Patrick; Dolag, Klaus; Pettorino, Valeria

    2012-01-01

    Aims: We assess the sensitivity of void shapes to the nature of dark energy that was pointed out in recent studies. We investigate whether or not void shapes are useable as an observational probe in galaxy redshift surveys. We focus on the evolution of the mean void ellipticity and its underlying physical cause. Methods: We analyse the morphological properties of voids in five sets of cosmological N-body simulations, each with a different nature of dark energy. Comparing voids in the dark matter distribution to those in the halo population, we address the question of whether galaxy redshift surveys yield sufficiently accurate void morphologies. Voids are identified using the parameter free Watershed Void Finder. The effect of redshift distortions is investigated as well. Results: We confirm the statistically significant sensitivity of voids in the dark matter distribution. We identify the level of clustering as measured by \\sigma_8(z) as the main cause of differences in mean void shape . We find that in the h...

  7. Cosmic voids and void lensing in the Dark Energy Survey Science Verification data

    Science.gov (United States)

    Sánchez, C.; Clampitt, J.; Kovacs, A.; Jain, B.; García-Bellido, J.; Nadathur, S.; Gruen, D.; Hamaus, N.; Huterer, D.; Vielzeuf, P.; Amara, A.; Bonnett, C.; DeRose, J.; Hartley, W. G.; Jarvis, M.; Lahav, O.; Miquel, R.; Rozo, E.; Rykoff, E. S.; Sheldon, E.; Wechsler, R. H.; Zuntz, J.; Abbott, T. M. C.; Abdalla, F. B.; Annis, J.; Benoit-Lévy, A.; Bernstein, G. M.; Bernstein, R. A.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Rosell, A. Carnero; Kind, M. Carrasco; Carretero, J.; Crocce, M.; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Evrard, A. E.; Neto, A. Fausti; Flaugher, B.; Fosalba, P.; Frieman, J.; Gaztanaga, E.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; James, D. J.; Krause, E.; Kuehn, K.; Lima, M.; Maia, M. A. G.; Marshall, J. L.; Melchior, P.; Plazas, A. A.; Reil, K.; Romer, A. K.; Sanchez, E.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Tarle, G.; Thomas, D.; Walker, A. R.; Weller, J.; DES Collaboration

    2017-02-01

    Cosmic voids are usually identified in spectroscopic galaxy surveys, where 3D information about the large-scale structure of the Universe is available. Although an increasing amount of photometric data is being produced, its potential for void studies is limited since photometric redshifts induce line-of-sight position errors of ≥50 Mpc h-1which can render many voids undetectable. We present a new void finder designed for photometric surveys, validate it using simulations, and apply it to the high-quality photo-z redMaGiC galaxy sample of the DES Science Verification data. The algorithm works by projecting galaxies into 2D slices and finding voids in the smoothed 2D galaxy density field of the slice. Fixing the line-of-sight size of the slices to be at least twice the photo-z scatter, the number of voids found in simulated spectroscopic and photometric galaxy catalogues is within 20 per cent for all transverse void sizes, and indistinguishable for the largest voids (Rv ≥ 70 Mpc h-1). The positions, radii, and projected galaxy profiles of photometric voids also accurately match the spectroscopic void sample. Applying the algorithm to the DES-SV data in the redshift range 0.2 < z < 0.8, we identify 87 voids with comoving radii spanning the range 18-120 Mpc h-1, and carry out a stacked weak lensing measurement. With a significance of 4.4σ, the lensing measurement confirms that the voids are truly underdense in the matter field and hence not a product of Poisson noise, tracer density effects or systematics in the data. It also demonstrates, for the first time in real data, the viability of void lensing studies in photometric surveys.

  8. Properties of Galaxies in and around Voids

    CERN Document Server

    Hopp, U

    1997-01-01

    Two surveys for intrinsically faint galaxies towards nearby voids have been conducted at the MPI für Astronomie, Heidelberg. One selected targets from a new diameter limited ($\\Phi \\ge 5''$) catalog with morphological criteria while the other used digitized objective prism Schmidt plates to select mainly HII dwarf galaxies. For some 450 galaxies, redshifts and other optical data were obtained. We studied the spatial distribution of the sample objects, their luminosity function, and their intrinsic properties. Most of the galaxies belong to already well known sheets and filaments. But we found about a dozen highly isolated galaxies in each sample (nearest neighborhood distance $\\ge 3 h_{75}^{-1} Mpc$). These tend to populate additional structures and are not distributed homogeneously throughout the voids. As our results on 'void galaxies' still suffer from small sample statistics, I also tried to combine similar existing surveys of nearby voids to get further hints on the larger structure and on the luminosit...

  9. Underground void filling by cemented mill tailings

    Institute of Scientific and Technical Information of China (English)

    Choudhary Bhanwar Singh; Kumar Santosh

    2013-01-01

    Underground mining always create voids. These voids can cause subsidence of surface. So it is always a demand to fill the void in such a manner that the effect of underground mining can be minimized. Void filling using mill tailings especially in metal mining is one of the best techniques. The tailings produced in milling process have traditionally been disposed in tailing ponds creating a waste disposal and environ-mental problems in terms of land degradation, air and water pollution, etc. This disposal practice is more acute in the metal milling industry where the fine grinding, required for value liberation, results in the production of very fine tailings in large percentage. This paper includes discussions on the effectiveness of different paste mixes with varying cement contents in paste backfilling operations. The results revealed that material composition and use of super plasticizer strongly influenced the strength of cemented backfill.

  10. 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...

  11. 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

  12. Zipf's law for fractal voids and a new void-finder

    CERN Document Server

    Gaite, J

    2005-01-01

    Voids are a prominent feature of fractal point distributions but there is no precise definition of what is a void (except in one dimension). Here we propose a definition of voids that uses methods of discrete stochastic geometry, in particular, Delaunay and Voronoi tessellations, and we construct a new algorithm to search for voids in a point set. We find and rank-order the voids of suitable examples of fractal point sets in one and two dimensions to test whether Zipf's power-law holds. We conclude affirmatively and, furthermore, that the rank-ordering of voids conveys similar information to the number-radius function, as regards the scaling regime and the transition to homogeneity. So it is an alternative tool in the analysis of fractal point distributions with crossover to homogeneity and, in particular, of the distribution of galaxies.

  13. Thermal Properties of Asphalt Mixtures Modified with Conductive Fillers

    Directory of Open Access Journals (Sweden)

    Byong Chol Bai

    2015-01-01

    Full Text Available This paper investigates the thermal properties of asphalt mixtures modified with conductive fillers used for snow melting and solar harvesting pavements. Two different mixing processes were adopted to mold asphalt mixtures, dry- and wet-mixing, and two conductive fillers were used in this study, graphite and carbon black. The thermal conductivity was compared to investigate the effects of asphalt mixture preparing methods, the quantity, and the distribution of conductive filler on thermal properties. The combination of conductive filler with carbon fiber in asphalt mixture was evaluated. Also, rheological properties of modified asphalt binders with conductive fillers were measured using dynamic shear rheometer and bending beam rheometer at grade-specific temperatures. Based on rheological testing, the conductive fillers improve rutting resistance and decrease thermal cracking resistance. Thermal testing indicated that graphite and carbon black improve the thermal properties of asphalt mixes and the combined conductive fillers are more effective than the single filler.

  14. Void Statistics and Void Galaxies in the 2dFGRS

    CERN Document Server

    von Benda-Beckmann, Alexander M

    2007-01-01

    For the 2dFGRS we study the properties of voids and of fainter galaxies within voids that are defined by brighter galaxies. Our results are compared with simulated galaxy catalogues from the Millenium simulation coupled with a semianalytical galaxy formation recipe. We derive the void size distribution and discuss its dependence on the faint magnitude limit of the galaxies defining the voids. While voids among faint galaxies are typically smaller than those among bright galaxies, the ratio of the void sizes to the mean galaxy separation reaches larger values. This is well reproduced in the mock galaxy samples studied. We provide analytic fitting functions for the void size distribution. Furthermore, we study the galaxy population inside voids defined by objects with $B_J -5\\log{h}< -20$ and diameter larger than 10 \\hMpc. We find a clear bimodality of the void galaxies similar to the average comparison sample. We confirm the enhanced abundance of galaxies in the blue cloud and a depression of the number of ...

  15. Cluster-Void Degeneracy Breaking: Dark Energy, Planck and the Largest Cluster & Void

    CERN Document Server

    Sahlén, Martin; Silk, Joseph

    2015-01-01

    Combining galaxy cluster and void abundances breaks the degeneracy between mean matter density $\\Omega_{\\rm m}$ and power spectrum normalization $\\sigma_8$. In a first for voids, we constrain $\\Omega_{\\rm m} = 0.21 \\pm 0.10$ and $\\sigma_8 = 0.95 \\pm 0.21$ for a flat $\\Lambda$CDM universe, using extreme-value statistics on the claimed largest cluster and void. The Planck-consistent results detect dark energy with two objects, independently of other dark energy probes. Cluster-void studies also offer complementarity in scale, density, and non-linearity - of particular interest for testing modified-gravity models.

  16. A New Void Fraction Measurement Method for Gas-Liquid Two-Phase Flow in Small Channels.

    Science.gov (United States)

    Li, Huajun; Ji, Haifeng; Huang, Zhiyao; Wang, Baoliang; Li, Haiqing; Wu, Guohua

    2016-01-27

    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.

  17. Filler functionality in edible solid foams

    NARCIS (Netherlands)

    Sman, van der R.G.M.

    2016-01-01

    We review the functionality of particulate ingredients in edible brittle foams, such as expanded starchy snacks. In food science and industry there is not a complete awareness of the full functionality of these filler ingredients, which can be fibers, proteins, starch granules and whole grains. B

  18. Tuning the Mechanical Properties of Tapioca Starch by Plasticizers, Inorganic Fillers and Agrowaste-Based Fillers

    OpenAIRE

    Edwin Azwar; Minna Hakkarainen

    2012-01-01

    Mechanical properties of tapioca starch-based films were tuned by different additives and additive combinations. The additives included plasticizers (glycerol, sorbitol, and citric acid), inorganic fillers (halloysite and kaolin), and agrowaste-based fillers (milled wood flour and rice bran). In addition, new biobased additives were prepared from wood flour and rice bran through liquefaction reaction. Through different additive combinations, starch-based materials with significant differences...

  19. Performance of ferrite fillers on electrical behavior of polymer nanocomposite electrolyte

    Science.gov (United States)

    Pandey, Kamlesh; Mauli Dwivedi, Mrigank; Singh, Markandey; Agrawal, S. L.

    2011-04-01

    Dispersal of nanofillers in polymer electrolytes have shown to improve the ionic properties of Polyethylene oxide (PEO)-based polymer electrolytes in recent times. The effects of different nanoferrite fillers (i.e., Al-Zn ferrite, Mg-Zn ferrite, and Zn ferrite) on the electrical transport properties have been studied here on the composite polymer electrolyte system. The interaction of salt/filler with electrolyte has been investigated by XRD studies. SEM image and infrared spectral studies give an indication of nanocomposite formation. In conductivity studies, all electrolyte systems are seen to follow universal power law. Composition dependence (with ferrite filler) gives the maximum conductivity in [93PEO-7NH4SCN]: X ferrite (where X = 2% in Al-Zn ferrite, 1% Mg-Zn ferrite, and 1% Zn ferrite) system.

  20. 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....

  1. Nanotubularchrysotile fillers for radiationand protective constructional composites

    Directory of Open Access Journals (Sweden)

    PAVLENKO Vyacheslav Ivanovich

    2016-08-01

    Full Text Available Strengthening of manifestation of quantum-dimensional effect in nanoparticles will make considerable impact on absorption of photon radiation. Therefore, application of ultradisperse systems will promote high-quality strengthening of radiation protective properties of material and will allow creation of more compact material with improved protective characteristics. The unique combination of properties of chrysotile allows creation of the materials on its basis which possess high mechanical and thermal strength, radiation resistance. The presence of the combined water in its structure favours appearance of radiation protective properties by neutron radiation in such materials. In this connection the authors offered to fill chrysotile nanotubes with nanodispersed compounds that make it possible to raise its radiation protective characteristics. As a result, these compounds have to possess higher extinction coefficient of γ-radiation, and respectively possess high density and content of heavy elements. Nanocrystal plumbous tungstate of PbWO4 is offered to use as compound for intercalation. The authors developed a method to produce nanotubular filler of radiation protective composite materials by filling hydrosilicate nanotubes of chrysotile structure with refractory slightly soluble compound on the basis of PbWO4 and serial processing of material with solutions of reagents. The best result has been achieved when chrysotile was treated consistently in K2WO4 and Pb(СН3СОО2 solutions, at the same time mass content of PbWO4 in an end product reaches 30%. The introduced K2WO4 filled nanotubes not only in the internal channel, but also in interlayered space, and localization of PbWO4 happens both in internal channels of nanotubes and on their surface. In spite of the fact that the developed technology does not allow us to modify chrysotile so that all injected PbWO4 could be contained only in internal canals of nanotubes, the obtained product gets

  2. Tracking and Increasing Viability of Topically Injected Fibroblasts Suspended in Hyaluronic Acid Filler.

    Science.gov (United States)

    You, Hi-Jin; Namgoong, Sik; Rhee, Sung-Mi; Han, Seung-Kyu

    2016-03-01

    A new injectable tissue-engineered soft tissue consisting of a mixture of hyaluronic acid (HA) filler and cultured human fibroblasts have been developed by the authors. To establish this method as a standard treatment, a further study was required to determine whether the injected fibroblasts could stay at the injected place or move to other sites. In addition, effective strategies were needed to increase viability of the injected fibroblasts. The purpose of this study was to track the injected fibroblasts and to determine the effect of adding prostaglandin E1 (PGE1) or vitamin C on the viability of fibroblasts.Human fibroblasts labeled with fluorescence dye were suspended in HA filler and injected into 4 sites on the back of nude mice. The injected bioimplants consisted of one of the 4 followings: HA filler without cells (HA group), fibroblasts suspended in HA filler (HA + FB group), PGE1-supplemented fibroblasts in HA filler (HA + FB + PGE1 group), and vitamin C-supplemented fibroblasts in HA filler (HA + FB + VC group). At 4 weeks after injection, locations and intensities of the fluorescence signals were evaluated using a live imaging system.The fluorescence signals of the fibroblast-containing groups were visible only at the injected sites without dispersing to other sites. The HA +FB + PGE1 group showed a significantly higher fluorescence signal than the HA + FB and the HA + FB +VC groups (P FB and HA + FB +VC groups (P = 0.69).The results of the current study collectively suggest that injected fibroblasts suspended in HA filler stay at the injected place without moving to other sites. In addition, PGE1 treatment may increase the remaining rhodamine B isothiocynanate dye at the injected site of the human dermal fibroblasts.

  3. Multiple void interaction of pipeline steel in triaxial stress fields

    Institute of Scientific and Technical Information of China (English)

    Bao-wen QIU; Ze-xi YUAN; Gui-feng ZHOU

    2008-01-01

    Three-dimensional unit cell models were developed to study the damage induced by void growth in ductile materials. Special emphasis is given to the influence of the void shape and random spatial void arrangements. The periodical void arrays of body cen-tered cubic are investigated by analyzing representative unit cells. The isotropic behavior of the matrix material is modeled using v. Mises plasticity. The cell models are analyzed by the large strain finite element method under monotonic loading while keeping the constant stress triaxiality. Results showed that when void density increased, effects of void aspects on void growth gradu-ally diminished.

  4. 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...... to the maximum principal tensile stress. A plane strain approximation is used, where the voids are parallel cylindrical holes. Clusters with different numbers of voids are compared with the growth of a single void, such that the total initial volume of the voids, and thus also the void volume fractions...... understanding, different transverse stresses on the unit cell are considered to see the influence of different levels of stress triaxiality. Also considered are different initial ratios of the void spacing to the void radius inside the clusters. And results are shown for different levels of strain hardening...

  5. Universal void density profiles from simulation and SDSS

    CERN Document Server

    Nadathur, S; Diego, J M; Iliev, I T; Gottlöber, S; Watson, W A; Yepes, G

    2014-01-01

    We discuss the universality and self-similarity of void density profiles, for voids in realistic mock luminous red galaxy (LRG) catalogues from the Jubilee simulation, as well as in void catalogues constructed from the SDSS LRG and Main Galaxy samples. Voids are identified using a modified version of the ZOBOV watershed transform algorithm, with additional selection cuts. We find that voids in simulation are self-similar, meaning that their average rescaled profile does not depend on the void size, or -- within the range of the simulated catalogue -- on the redshift. Comparison of the profiles obtained from simulated and real voids shows an excellent match. The profiles of real voids also show a universal behaviour over a wide range of galaxy luminosities, number densities and redshifts. This points to a fundamental property of the voids found by the watershed algorithm, which can be exploited in future studies of voids.

  6. Universal void density profiles from simulation and SDSS

    Science.gov (United States)

    Nadathur, S.; Hotchkiss, S.; Diego, J. M.; Iliev, I. T.; Gottlöber, S.; Watson, W. A.; Yepes, G.

    2016-10-01

    We discuss the universality and self-similarity of void density profiles, for voids in realistic mock luminous red galaxy (LRG) catalogues from the Jubilee simulation, as well as in void catalogues constructed from the SDSS LRG and Main Galaxy samples. Voids are identified using a modified version of the ZOBOV watershed transform algorithm, with additional selection cuts. We find that voids in simulation are self-similar, meaning that their average rescaled profile does not depend on the void size, or - within the range of the simulated catalogue - on the redshift. Comparison of the profiles obtained from simulated and real voids shows an excellent match. The profiles of real voids also show a universal behaviour over a wide range of galaxy luminosities, number densities and redshifts. This points to a fundamental property of the voids found by the watershed algorithm, which can be exploited in future studies of voids.

  7. Effect of filler wire on the joint properties of AZ31 magnesium alloys using CO2 laser welding

    Institute of Scientific and Technical Information of China (English)

    Wang Hongying; Li Zhijun

    2007-01-01

    Laser welding with filler wire of AZ31 magnesium alloys is investigated using a CO2 laser experimental system. The effect of three different filler wires on the joint properties is researched. The results show that the weld appearance can be effectively improved when using laser welding with filler wire. The microhardness and tensile strength of joints are almost the same as those of the base metal when ER AZ31 or ER AZ61 wire is adopted. However, when the filler wire of ER 5356 aluminum alloy is used, the mechanical properties of joints become worse. For ER AZ31 and ER AZ61 filler wires, the microstructure of weld zone shows small dendrite grains. In comparison, for ER 5356 filler wire, the weld shows a structure of snowy dendrites and many intermetallic compounds and eutectic phases distribute in the dendrites. These intermetallic constituents with low melting point increase the tendency of hot crack and result in fragile joint properties. Therefore, ER AZ31 and ER AZ61 wire are more suitable filler material than ER 5356 for CO2 laser welding of AZ31 magnesium alloys.

  8. Bioactive glass particulate filler composite: Effect of coupling of fillers and filler loading on some physical properties.

    Science.gov (United States)

    Oral, Onur; Lassila, Lippo V; Kumbuloglu, Ovul; Vallittu, Pekka K

    2014-05-01

    The aim of this study was to investigate the effect of silanization of biostable and bioactive glass fillers in a polymer matrix on some of the physical properties of the composite. The water absorption, solubility, flexural strength, flexural modulus and toughness of different particulate filler composite resins were studied in vitro. Five different specimen groups were analyzed: A glass-free control, a non-silanized bioactive glass, a silanized bioactive glass, a non-silanized biostable glass and a silanized biostable glass groups. All of these five groups were further divided into sub-groups of dry and water-stored materials, both of them containing groups with 3wt%, 6wt%, 9wt% or 12wt% of glass particles (n=8 per group). The silanization of the glass particles was carried out with 2% of gamma-3-methacryloxyproyltrimethoxysilane (MPS). For the water absorption and solubility tests, the test specimens were stored in water for 60 days, and the percentages of weight change were statistically analyzed. Flexural strength, flexural modulus and toughness values were tested with a three-point bending test and statistically analyzed. Higher solubility values were observed in non-silanized glass in proportion to the percentage of glass particles. Silanization, on the other hand, decreased the solubility values of both types of glass particles and polymer. While 12wt% non-silanized bioactive glass specimens showed -0.98wt% solubility, 12wt% silanized biostable glass specimens were observed to have only -0.34wt% solubility. The three-point bending results of the dry specimens showed that flexural strength, toughness and flexural modulus decreased in proportion to the increase of glass fillers. The control group presented the highest results (106.6MPa for flexural strength, 335.7kPA for toughness, 3.23GPa for flexural modulus), whereas for flexural strength and toughness, 12wt% of non-silanized biostable glass filler groups presented the lowest (70.3MPa for flexural strength

  9. Blocking effect of twin boundaries on partial dislocation emission from void surfaces.

    Science.gov (United States)

    Zhang, Lifeng; Zhou, Haofei; Qu, Shaoxing

    2012-03-02

    Recent discovery that nanoscale twin boundaries can be introduced in ultrafine-grained metals to improve strength and ductility has renewed interest in the mechanical behavior and deformation mechanisms of these nanostructured materials. By controlling twin boundary spacing, the effect of twin boundaries on void growth is investigated by using atomistic simulation method. The strength is significantly enhanced due to the discontinuous slip system associated with these coherent interfaces. Atomic-scale mechanisms underlying void growth, as well as the interaction between twin boundaries and the void, are revealed in details.

  10. 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 sough...

  11. A study of void effects on the interlaminar shear strength of unidirectional graphite fiber reinforced composites

    Science.gov (United States)

    Bowles, Kenneth J.; Frimpong, Stephen

    1990-01-01

    A study was conducted to evaluate the effect of voids on the interlaminar shear strength (ILSS) of a polyimide matrix composite system. The graphite/PRM-15 composite was chosen for study because of the extensive amount of experience that has been amassed in the processing of this material. Composite densities and fiber contents of more than thirty different laminates were measured along with ILSS. Void contents were calculated and the void geometry and distribution were noted using microscopic techniques such as those used in metallography. It was found that there was a good empirical correlation between ILSS and composite density. The most acceptable relationship between the ILSS and density was found to be a power equation which closely resembles theoretically derived expressions. An increase in scatter in the strength data was observed as the void content increased. In laminates with low void content, the void appears to be more segregated in one area of the laminate. It was found that void free composites could be processed in matched metal die molds at pressures greater than 1.4 and less than 6.9 MPa.

  12. Cosmic Voids: structure, dynamics and galaxies

    CERN Document Server

    van de Weygaert, Rien

    2009-01-01

    In this review we discuss several aspects of Cosmic Voids. Voids are a major component of the large scale distribution of matter and galaxies in the Universe. They are of instrumental importance for understanding the emergence of the Cosmic Web. Their relatively simple shape and structure makes them into useful tools for extracting the value of a variety cosmic parameters, possibly including even that of the influence of dark energy. Perhaps most promising and challenging is the issue of the galaxies found within their realm. Not only does the pristine environment of voids provide a promising testing ground for assessing the role of environment on the formation and evolution of galaxies, the dearth of dwarf galaxies may even represent a serious challenge to the standard view of cosmic structure formation.

  13. Void coalescence within periodic clusters of particles

    Science.gov (United States)

    Thomson, C. I. A.; Worswick, M. J.; Pilkey, A. K.; Lloyd, D. J.

    2003-01-01

    The effect of particle clustering on void damage rates in a ductile material under triaxial loading conditions is examined using three-dimensional finite element analysis. An infinite material containing a regular distribution of clustered particles is modelled using a unit cell approach. Three discrete particles are introduced into each unit cell while a secondary population of small particles within the surrounding matrix is represented using the Gurson-Tvergaard-Needleman (GTN) constitutive equations. Deformation strain states characteristic of sheet metal forming are considered; that is, deep drawing, plane strain and biaxial stretching. Uniaxial tensile stress states with varying levels of superimposed hydrostatic tension are also examined. The orientation of a particle cluster with respect to the direction of major principal loading is shown to significantly influence failure strains. Coalescence of voids within a first-order particle cluster (consisting of three particles) is a stable event while collapse of inter-cluster ligaments leads to imminent material collapse through void-sheeting.

  14. Effectiveness of tolterodine in nonneurogenic voiding dysfunction.

    Science.gov (United States)

    Babu, Ramesh

    2006-11-01

    The efficacy of tolterodine was analysed in children with non-neurogenic voiding dysfunction, using dysfunctional voiding symptom score (DVSS). Of 44 patients (mean age 9.3 yrs; M:F = 25:19), 36 received long acting tolterodine tartrate at a dose of 2mg OD and 8 at a dose of 4mg OD. The mean (SD) DVSS before and after the treatment was 17.1 (2.8) and 12.0 (2.4). There was a significant improvement in the mean DVSS score at the end of the treatment (Students t test P tolterodine is effective in children with voiding dysfunction. The single daily dose has good compliance and minimal side effect profile.

  15. Mechanical properties and filler distribution as a function filler content in silica filled PDMS samples

    Energy Technology Data Exchange (ETDEWEB)

    Hawley, M. E. (Marilyn E.); Wrobleski, Debra A.; Orler, E. B. (E. Bruce); Houlton, R. J. (Robert J.); Chitanvis, K. E. (Kiran E.); Brown, G. W. (Geoffrey W.); Hanson, D. E. (David E.)

    2004-01-01

    Atomic force microscopy (AFM) phase imaging and tensile stress-strain measurements are used to study a series of model compression molded fumed silica filled polydimethysiloxane (PDMS) samples with filler content of zero, 20, 35, and 50 parts per hundred (phr) to determine the relationship between filler content and stress-strain properties. AFM phase imaging was used to determine filler size, degree of aggregation, and distribution within the soft PDMS matrix. A small tensile stage was used to measure mechanical properties. Samples were not pulled to break in order to study Mullins and aging effects. Several identical 35 phr samples were subjected to an initial stress, and then one each was reevaluated over intervals up to 26 weeks to determine the degree to which these samples recovered their initial stress-strain behavior as a function of time. One sample was tested before and after heat treatment to determine if heating accelerated recovery of the stress-strain behavior. The effect of filler surface treatment on mechanical properties was examined for two samples containing 35 phr filler treated or untreated with hexamethyldisilazane (HMDZ), respectively. Fiduciary marks were used on several samples to determine permanent set. 35 phr filler samples were found to give the optimum mechanical properties. A clear Mullins effect was seen. Within experimental error, no change was seen in mechanical behavior as a function of time or heat-treatment. The mechanical properties of the sample containing the HDMZ treated silica were adversely affected. AFM phase images revealed aggregation and nonuniform distribution of the filler for all samples. Finally, a permanent set of about 3 to 6 percent was observed for the 35 phr samples.

  16. Malposition of catheters during voiding cystourethrography

    Energy Technology Data Exchange (ETDEWEB)

    Rathaus, V.; Konen, O.; Shapiro, M. [Dept. of Diagnostic Imaging Sapir Medical Center, Kfar-Saba and Sackler Medical School, Tel Aviv University (Israel); Grunebaum, M. [Veteran Pediatric Radiologist, Kfar Saba (Israel)

    2001-04-01

    The aim of this study was to report catheter malposition during voiding cystourethrography. Eight hundred forty-three voiding cystourethrography (265 males and 578 females, aged 1 week to 12 years, mean age 2 years) were performed during a period of 4 years. The conventional standard procedure was applied. In 3 cases with passed history of urinary tract infection the catheter entered directly into the ureter. In all these cases the uretero-vesical reflux was present on the same side where the catheter entered. It appears that insertion of a catheter into the ureter is possible only in the presence of an anomaly or pathology at the vesicoureteric junction. (orig.)

  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)....

  18. Large Scale Structure in Absorption: Gas within and around Galaxy Voids

    CERN Document Server

    Tejos, Nicolas; Crighton, Neil H M; Theuns, Tom; Altay, Gabriel; Finn, Charles W

    2012-01-01

    We investigate the properties of the HI Ly-a absorption systems (Ly-a forest) within and around galaxy voids at z99% c.l.) of Ly-a systems at the edges of galaxy voids with respect to a random distribution, on ~5 h^{-1} Mpc scales. We find no significant difference in the number of systems inside voids with respect to the random expectation. We report differences between both column density (N_{HI}) and Doppler parameter (b_{HI}) distributions of Ly-a systems found inside and at the edge of galaxy voids at the >98% and >90% c.l. respectively. Low density environments (voids) have smaller values for both N_{HI} and b_{HI} than higher density ones (edges of voids). These trends are theoretically expected and also found in GIMIC, a state-of-the-art hydrodynamical simulation. Our findings are consistent with a scenario of at least three types of Ly-alpha: (1) containing embedded galaxies and so directly correlated with galaxies (referred as `halo-like'), (2) correlated with galaxies only because they lie in the s...

  19. Dermal fillers for tissue augmentation: an overview

    Directory of Open Access Journals (Sweden)

    Zeplin, Philip H.

    2014-06-01

    Full Text Available [english] Treatments with dermal fillers for tissue augmentation constitute the majority of all non-surgical procedures in plastic surgery. Newly developed products get launched and the market grows continuously, but the “ideal” substance has yet not been found. The substances used these days are high molecular compounds. They have substantial differences in their physicochemical properties and are suspended in complex matrices. This overview describes the latest history of dermal fillers and the commonly used substances of different origin and formalizes the need for the development of systematic procedures of standardized pre-clinical tests with subsequent certification as well as the establishment of interdisciplinary clinical guidelines to ensure custumer’s safety.

  20. Void Reactivity Coefficient Analysis during Void Fraction Changes in Innovative BWR Assemblies

    Directory of Open Access Journals (Sweden)

    Andrius Slavickas

    2015-01-01

    Full Text Available The study of the void reactivity variation in innovative BWR fuel assemblies is presented in this paper. The innovative assemblies are loaded with high enrichment fresh UO2 and MOX fuels. UO2 fuel enrichment is increased above existing design limitations for LWR fuels (>5%. MOX fuel enrichment with fissile Pu content is established to achieve the same burnup level as that of high enrichment UO2 fuel. For the numerical analysis, the TRITON functional module of SCALE 6.1 code with the 238-group ENDF/B-VI cross section data library was applied. The investigation of the void reactivity feedback is performed in the entire 0–100% void fraction range. Higher values of void reactivity coefficient for assembly loaded with MOX fuel are found in comparison with values for assembly loaded with UO2 fuel. Moreover, coefficient values for MOX fuel are positive over 75% void fraction. The variation of the void reactivity coefficient is explained by the results of the decomposition analysis based on four-factor formula and neutron absorption reactions for main isotopes. Additionally, the impact of the moderation enhancement on the void reactivity coefficient was investigated for the innovative assembly with MOX fuel.

  1. Cosmic Voids and Void Lensing in the Dark Energy Survey Science Verification Data

    CERN Document Server

    Sánchez, C; Kovacs, A; Jain, B; García-Bellido, J; Nadathur, S; Gruen, D; Hamaus, N; Huterer, D; Vielzeuf, P; Amara, A; Bonnett, C; DeRose, J; Hartley, W G; Jarvis, M; Lahav, O; Miquel, R; Rozo, E; Rykoff, E S; Sheldon, E; Wechsler, R H; Zuntz, J; Abbott, T M C; Abdalla, F B; Annis, J; Benoit-Lévy, A; Bernstein, G M; Bernstein, R A; Bertin, E; Brooks, D; Buckley-Geer, E; Rosell, A Carnero; Kind, M Carrasco; Carretero, J; Crocce, M; Cunha, C E; D'Andrea, C B; da Costa, L N; Desai, S; Diehl, H T; Dietrich, J P; Doel, P; Evrard, A E; Neto, A Fausti; Flaugher, B; Fosalba, P; Frieman, J; Gaztanaga, E; Gruendl, R A; Gutierrez, G; Honscheid, K; James, D J; Krause, E; Kuehn, K; Lima, M; Maia, M A G; Marshall, J L; Melchior, P; Plazas, A A; Reil, K; Romer, A K; Sanchez, E; Schubnell, M; Sevilla-Noarbe, I; Smith, R C; Soares-Santos, M; Sobreira, F; Suchyta, E; Tarle, G; Thomas, D; Walker, A R; Weller, J

    2016-01-01

    Galaxies and their dark matter halos populate a complicated filamentary network around large, nearly empty regions known as cosmic voids. Cosmic voids are usually identified in spectroscopic galaxy surveys, where 3D information about the large-scale structure of the Universe is available. Although an increasing amount of photometric data is being produced, its potential for void studies is limited since photometric redshifts induce line-of-sight position errors of $\\sim50$ Mpc/$h$ or more that can render many voids undetectable. In this paper we present a new void finder designed for photometric surveys, validate it using simulations, and apply it to the high-quality photo-$z$ redMaGiC galaxy sample of the Dark Energy Survey Science Verification (DES-SV) data. The algorithm works by projecting galaxies into 2D slices and finding voids in the smoothed 2D galaxy density field of the slice. Fixing the line-of-sight size of the slices to be at least twice the photo-$z$ scatter, the number of voids found in these ...

  2. Validation uncertainty of MATRA code for subchannel void distributions

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Dae-Hyun; Kim, S. J.; Kwon, H.; Seo, K. W. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    To extend code capability to the whole core subchannel analysis, pre-conditioned Krylov matrix solvers such as BiCGSTAB and GMRES are implemented in MATRA code as well as parallel computing algorithms using MPI and OPENMP. It is coded by fortran 90, and has some user friendly features such as graphic user interface. MATRA code was approved by Korean regulation body for design calculation of integral-type PWR named SMART. The major role subchannel code is to evaluate core thermal margin through the hot channel analysis and uncertainty evaluation for CHF predictions. In addition, it is potentially used for the best estimation of core thermal hydraulic field by incorporating into multiphysics and/or multi-scale code systems. In this study we examined a validation process for the subchannel code MATRA specifically in the prediction of subchannel void distributions. The primary objective of validation is to estimate a range within which the simulation modeling error lies. The experimental data for subchannel void distributions at steady state and transient conditions was provided on the framework of OECD/NEA UAM benchmark program. The validation uncertainty of MATRA code was evaluated for a specific experimental condition by comparing the simulation result and experimental data. A validation process should be preceded by code and solution verification. However, quantification of verification uncertainty was not addressed in this study. The validation uncertainty of the MATRA code for predicting subchannel void distribution was evaluated for a single data point of void fraction measurement at a 5x5 PWR test bundle on the framework of OECD UAM benchmark program. The validation standard uncertainties were evaluated as 4.2%, 3.9%, and 2.8% with the Monte-Carlo approach at the axial levels of 2216 mm, 2669 mm, and 3177 mm, respectively. The sensitivity coefficient approach revealed similar results of uncertainties but did not account for the nonlinear effects on the

  3. Technical Considerations for Filler and Neuromodulator Refinements

    Science.gov (United States)

    Wilson, Anthony J.; Chang, Brian L.; Percec, Ivona

    2016-01-01

    Background: The toolbox for cosmetic practitioners is growing at an unprecedented rate. There are novel products every year and expanding off-label indications for neurotoxin and soft-tissue filler applications. Consequently, aesthetic physicians are increasingly challenged by the task of selecting the most appropriate products and techniques to achieve optimal patient outcomes. Methods: We employed a PubMed literature search of facial injectables from the past 10 years (2005–2015), with emphasis on those articles embracing evidence-based medicine. We evaluated the scientific background of every product and the physicochemical properties that make each one ideal for specific indications. The 2 senior authors provide commentary regarding their clinical experience with specific technical refinements of neuromodulators and soft-tissue fillers. Results: Neurotoxins and fillers are characterized by unique physical characteristics that distinguish each product. This results in subtle but important differences in their clinical applications. Specific indications and recommendations for the use of the various neurotoxins and soft-tissue fillers are reviewed. The discussion highlights refinements in combination treatments and product physical modifications, according to specific treatment zones. Conclusions: The field of facial aesthetics has evolved dramatically, mostly secondary to our increased understanding of 3-dimensional structural volume restoration. Our work reviews Food and Drug Administration–approved injectables. In addition, we describe how to modify products to fulfill specific indications such as treatment of the mid face, décolletage, hands, and periorbital regions. Although we cannot directly evaluate the duration or exact physical properties of blended products, we argue that “product customization” is safe and provides natural results with excellent patient outcomes. PMID:28018778

  4. Technical Considerations for Filler and Neuromodulator Refinements.

    Science.gov (United States)

    Montes, José Raúl; Wilson, Anthony J; Chang, Brian L; Percec, Ivona

    2016-12-01

    Background: The toolbox for cosmetic practitioners is growing at an unprecedented rate. There are novel products every year and expanding off-label indications for neurotoxin and soft-tissue filler applications. Consequently, aesthetic physicians are increasingly challenged by the task of selecting the most appropriate products and techniques to achieve optimal patient outcomes. Methods: We employed a PubMed literature search of facial injectables from the past 10 years (2005-2015), with emphasis on those articles embracing evidence-based medicine. We evaluated the scientific background of every product and the physicochemical properties that make each one ideal for specific indications. The 2 senior authors provide commentary regarding their clinical experience with specific technical refinements of neuromodulators and soft-tissue fillers. Results: Neurotoxins and fillers are characterized by unique physical characteristics that distinguish each product. This results in subtle but important differences in their clinical applications. Specific indications and recommendations for the use of the various neurotoxins and soft-tissue fillers are reviewed. The discussion highlights refinements in combination treatments and product physical modifications, according to specific treatment zones. Conclusions: The field of facial aesthetics has evolved dramatically, mostly secondary to our increased understanding of 3-dimensional structural volume restoration. Our work reviews Food and Drug Administration-approved injectables. In addition, we describe how to modify products to fulfill specific indications such as treatment of the mid face, décolletage, hands, and periorbital regions. Although we cannot directly evaluate the duration or exact physical properties of blended products, we argue that "product customization" is safe and provides natural results with excellent patient outcomes.

  5. Effect of filler addition on the compressive and impact properties of glass fibre reinforced epoxy

    Indian Academy of Sciences (India)

    Nikhil Gupta; Balraj Singh Brar; Eyassu Woldesenbet

    2001-04-01

    Flyash is incorporated in glass fibre reinforced epoxies to study their response to the filler addition. Low cost of flyash can reduce the overall cost of the component. Only very low volume fractions of filler are investigated in the present study. To obtain further clarification of the observed phenomenon, another abundantly available low cost material, calcium carbonate is incorporated in one set of the specimens. Compressive strength of the material is found to decrease, whereas steep increase in impact strength is observed by introduction of very small quantity of fillers. Specimens containing calcium carbonate are tested for impact properties only. Effect of specimen aspect ratio on the compressive strength values is also studied by testing specimens of three different aspect ratios. Scanning electron microscopic observations are taken to develop a better understanding of the phenomena taking place in the material system at microscopic level.

  6. Structural analyses of a rigid pavement overlaying a sub-surface void

    Science.gov (United States)

    Adam, Fatih Alperen

    Pavement failures are very hazardous for public safety and serviceability. These failures in pavements are mainly caused by subsurface voids, cracks, and undulation at the slab-base interface. On the other hand, current structural analysis procedures for rigid pavement assume that the slab-base interface is perfectly planar and no imperfections exist in the sub-surface soil. This assumption would be violated if severe erosion were to occur due to inadequate drainage, thermal movements, and/or mechanical loading. Until now, the effect of erosion was only considered in the faulting performance model, but not with regards to transverse cracking at the mid-slab edge. In this research, the bottom up fatigue cracking potential, caused by the combined effects of wheel loading and a localized imperfection in the form of a void below the mid-slab edge, is studied. A robust stress and surface deflection analysis was also conducted to evaluate the influence of a sub-surface void on layer moduli back-calculation. Rehabilitative measures were considered, which included a study on overlay and fill remediation. A series regression of equations was proposed that provides a relationship between void size, layer moduli stiffness, and the overlay thickness required to reduce the stress to its original pre-void level. The effect of the void on 3D pavement crack propagation was also studied under a single axle load. The amplifications to the stress intensity was shown to be high but could be mitigated substantially if stiff material is used to fill the void and impede crack growth. The pavement system was modeled using the commercial finite element modeling program Abaqus RTM. More than 10,000 runs were executed to do the following analysis: stress analysis of subsurface voids, E-moduli back-calculation of base layer, pavement damage calculations of Beaumont, TX, overlay thickness estimations, and mode I crack analysis. The results indicate that the stress and stress intensity are, on

  7. Evaluation of dermal fillers with noncontact optical coherence elastography

    Science.gov (United States)

    Singh, Manmohan; Wang, Shang; Yee, Richard W.; Han, Zhaolong; Aglyamov, Salavat R.; Larin, Kirill V.

    2017-02-01

    Over 2 million dermal filler procedures are performed each year in the USA alone, and this figure is only expected to increase as the aging population continues to grow. Dermal filler treatments can last from a few months to years depending on the type of filler and its placement. Although adverse reactions are rare, they can be quite severe due to ischemic events and filler migration. Previously, techniques such as ultrasound or magnetic resonance imaging have been used to evaluate the filler injections. However, these techniques are not practical for real-time filler injection guidance due to limitations such as the physical presence of the transducer. In this work, we propose the use of optical coherence tomography (OCT) for image-guided dermal filler injections due to the high spatial and temporal resolution of OCT. In addition, we utilize a noncontact optical coherence elastography (OCE) technique, to evaluate the efficacy of the dermal filler injection. A grid of air-pulse OCE measurements was taken, and the dynamic response of the skin to the air-pulse was translated to the Young's modulus and shear viscosity. Our results show that OCT was able to visualize the dermal filler injection process, and that OCE was able to localize the dermal filler injection sites. Combined with functional techniques such as optical microangiography, and recent advanced in OCT hardware, OCT may be able to provide real-time injection guidance in 3D by visualizing blood vessels to prevent ischemic events.

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

    DEFF Research Database (Denmark)

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

    2002-01-01

    A series of kinetic Monte Carlo computer experiments performed on idealized systems clearly reveals the dramatic effects of 1-D migration of self-interstitial atom (SIA) crowdion clusters on the stability of void lattices. In the presence of migrating SIA, void lattices are shown to be unstable u...

  9. Measurement of post-void residual urine

    NARCIS (Netherlands)

    Asimakopoulos, Anastasios D.; De Nunzio, Cosimo; Kocjancic, Ervin; Tubaro, Andrea; Rosier, Peter F.; Finazzi-Agrò, Enrico

    2016-01-01

    Aims To present the teaching module "Measurement of Post-void residual urine." Methods This module has been prepared by a Working Group of the ICS Urodynamics Committee. The methodology used included comprehensive literature review, consensus formation by the members of the Working Group, and review

  10. Void fraction instrument acceptance test procedure

    Energy Technology Data Exchange (ETDEWEB)

    Pearce, K.L.

    1994-09-15

    This acceptance test procedure (ATP) was written to test the void fraction instrument (VFI) and verify that the unit is ready for field service. The procedure verifies that the mechanical and electrical features (not specifically addressed in the software ATP) and software alarms are operating as designed.

  11. 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 ...

  12. 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...

  13. Void fraction instrument acceptance test procedure

    Energy Technology Data Exchange (ETDEWEB)

    Pearce, K.L.

    1994-09-15

    This acceptance test procedure (ATP) was written to test the void fraction instrument (VFI) and verify that the unit is ready for field service. The procedure verifies that the mechanical and electrical features (not specifically addressed in the software ATP) and software alarms are operating as designed.

  14. "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.

  15. The Metallicity of Void Dwarf Galaxies

    NARCIS (Netherlands)

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

    2015-01-01

    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 assumptio

  16. Atomistic modeling of shock-induced void collapse in copper

    Energy Technology Data Exchange (ETDEWEB)

    Davila, L P; Erhart, P; Bringa, E M; Meyers, M A; Lubarda, V A; Schneider, M S; Becker, R; Kumar, M

    2005-03-09

    Nonequilibrium molecular dynamics (MD) simulations show that shock-induced void collapse in copper occurs by emission of shear loops. These loops carry away the vacancies which comprise the void. The growth of the loops continues even after they collide and form sessile junctions, creating a hardened region around the collapsing void. The scenario seen in our simulations differs from current models that assume that prismatic loop emission is responsible for void collapse. We propose a new dislocation-based model that gives excellent agreement with the stress threshold found in the MD simulations for void collapse as a function of void radius.

  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

    The effects of void size and hardening in a hexagonal close-packed single crystal containing a cylindrical void loaded by a far-field equibiaxial tensile stress under plane strain conditions are studied. The crystal has three in-plane slip systems oriented at the angle 60 degrees with respect...... 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...... to three times higher for smaller void sizes than for larger void sizes in the non-local material....

  18. Failure by void coalescence in metallic materials containing primary and secondary voids subject to intense shearing

    DEFF Research Database (Denmark)

    Nielsen, Kim Lau; Tvergaard, Viggo

    2011-01-01

    , subject to shear dominated loading. To account for both length scales involved in this study, a continuum model that includes the softening effect of damage evolution in shear is used to represent the matrix material surrounding the primary voids. Here, a recently extended Gurson-type model is used, which......Failure under intense shearing at close to zero stress triaxiality is widely observed for ductile metallic materials, and is identified in experiments as smeared-out dimples on the fracture surface. Numerical cell-model studies of equal sized voids have revealed that the mechanism governing...... secondary damage that co-exists with or nucleation in the ligaments between larger voids that coalesce during intense shearing. A numerical cell-model study is carried out to gain a parametric understanding of the overall material response for different initial conditions of the two void populations...

  19. Ultrasound detection and identification of cosmetic fillers in the skin

    DEFF Research Database (Denmark)

    Wortsman, X.; Wortsman, J.; Orlandi, C.

    2012-01-01

    Background While the incidence of cosmetic filler injections is rising world-wide, neither exact details of the procedure nor the agent used are always reported or remembered by the patients. Thus, although complications are reportedly rare, availability of a precise diagnostic tool to detect...... cutaneous filler deposits could help clarify the association between the procedure and the underlying pathology. Objectives The aim of this study was to evaluate cutaneous sonography in the detection and identification of cosmetic fillers deposits and, describe dermatological abnormalities found associated...... with the presence of those agents. Methods We used ultrasound in a porcine skin model to determine the sonographic characteristics of commonly available filler agents, and subsequently applied the analysis to detect and identify cosmetic fillers among patients referred for skin disorders. Results Fillers...

  20. Synthesis of nanodispersed filler for polymer composite materials of thermostatic purpose

    Directory of Open Access Journals (Sweden)

    PAVLENKO Vyacheslav Ivanovich

    2016-10-01

    Full Text Available The paper presents data on the synthesis of nanosized filler for nonpolar polymer matrix. Aqueous solution of sodium methylsiliconate with empirical formula CH3–Si(OH2ONa was used as the base component for the synthesis of nanosized filler. The production process of filler consists of several stages, these are the main ones: synthesizing of gel that was obtained in gel formation from sol colloidal solution – transformation of free-dispersed system (sol into connected-dispersed one; gel precipitation by centrifugation and washing from ion Na+; gel drying at temperature of 100оC to obtain a powder filler; dispersion in the mill to the particle size of 0,1–1 microns. To destroy globules and diminish particle size to nanoscale level the obtained material was exposed to dispersion in planetary mill with further sonication (22 Hz. To study the obtained filler X-ray, differential thermal and microscopic methods have been used. For quantification of colloidal component (nanoparticles in the suspension the centrifugation method was used at high speeds. It has been determined that the content of nanoparticles (up to 200 nm in the obtained substance is about 10%. Damping edge angle of the obtained material is 110–120оC, that shows high hydrophobic properties of the synthesized powder. The obtained material possesses high dispersiveness, hydrophobicity and silicone frame resistant to the temperature range up to 531оC (there are no significant chemical transformations except dealkylation and dehydration reactions. Thermal degradation of the synthesized filler distinctly observed at the temperaturemore than 531оC.

  1. A Cosmic Watershed: the WVF Void Detection Technique

    CERN Document Server

    Platen, Erwin; Jones, Bernard J T

    2007-01-01

    On megaparsec scales the Universe is permeated by an intricate filigree of clusters, filaments, sheets and voids, the Cosmic Web. For the understanding of its dynamical and hierarchical history it is crucial to identify objectively its complex morphological components. One of the most characteristic aspects is that of the dominant underdense Voids, the product of a hierarchical process driven by the collapse of minor voids in addition to the merging of large ones. In this study we present an objective void finder technique which involves a minimum of assumptions about the scale, structure and shape of voids. Our void finding method, the Watershed Void Finder (WVF), is based upon the Watershed Transform, a well-known technique for the segmentation of images. Importantly, the technique has the potential to trace the existing manifestations of a void hierarchy. The basic watershed transform is augmented by a variety of correction procedures to remove spurious structure resulting from sampling noise. This study c...

  2. Filler metal alloy for welding cast nickel aluminide alloys

    Science.gov (United States)

    Santella, M.L.; Sikka, V.K.

    1998-03-10

    A filler metal alloy used as a filler for welding cast nickel aluminide alloys contains from about 15 to about 17 wt. % chromium, from about 4 to about 5 wt. % aluminum, equal to or less than about 1.5 wt. % molybdenum, from about 1 to about 4.5 wt. % zirconium, equal to or less than about 0.01 wt. % yttrium, equal to or less than about 0.01 wt. % boron and the balance nickel. The filler metal alloy is made by melting and casting techniques such as are melting the components of the filler metal alloy and cast in copper chill molds. 3 figs.

  3. Filler metal alloy for welding cast nickel aluminide alloys

    Energy Technology Data Exchange (ETDEWEB)

    Santella, Michael L. (Knoxville, TN); Sikka, Vinod K. (Oak Ridge, TN)

    1998-01-01

    A filler metal alloy used as a filler for welding east nickel aluminide alloys contains from about 15 to about 17 wt. % chromium, from about 4 to about 5 wt. % aluminum, equal to or less than about 1.5 wt. % molybdenum, from about 1 to about 4.5 wt. % zirconium, equal to or less than about 0.01 wt. % yttrium, equal to or less than about 0.01 wt. % boron and the balance nickel. The filler metal alloy is made by melting and casting techniques such as are melting the components of the filler metal alloy and east in copper chill molds.

  4. New Filler Material for Reference Free Part Encapsulation Fixture

    Institute of Scientific and Technical Information of China (English)

    LI Bei-zhi; YANG Jian-guo; ZHOU Hu

    2002-01-01

    Reference free part encapsulation (RFPE) is a nontraditional universal fixturing technique. In this paper,new filler material-a lower melting point alloy for RFPE technique is introduced. Based on experiment, the shrinlkage and expansion rate, the effect of filler on workpiece drift and the effect of filler thickness on cutting distortion are studied. The alloy has a good mechanical and physical performance and the need of RFPE fixturing can be perfectly satisfied. The result shows that if the formula and process parameters of filler material are properly selected, it can obviously improve the quality of the workpiece, enhance the machining efficiency and reduce the manufacturing cost.

  5. Coaggregation of mineral filler particles and starch granules as a basis for improving filler-fiber interaction in paper production.

    Science.gov (United States)

    Li, Ting; Fan, Jun; Chen, Wensen; Shu, Jiayan; Qian, Xueren; Wei, Haifeng; Wang, Qingwen; Shen, Jing

    2016-09-20

    The sustainable, efficient use of renewable bio-based additives in the production of various materials fits well into the concept of sustainability. Here, the concept of coaggregation of mineral filler particles and starch granules for improving filler-fiber interaction in paper-based cellulosic networks is presented. Coaggregation of precipitated calcium carbonate filler particles and uncooked, unmodified corn starch granules by cationic polyacrylamide (a cationic high molecular weight polymer flocculant) in combination with bentonite (an anionic microparticle) prior to addition to cellulosic fiber slurry delivered enhanced filler bondability with cellulosic fibers. For instance, under the conditions studied, preaggregation resulted in an increase in filler bondability factor from 9.24 to 15.21 at starch dosage of 1% (on the basis of the dry weight of papermaking stock). The swelling and gelatinization of the starch granules in starch-filler preaggregates or hybrids enabled the "bridging" of the gaps in cellulosic networks, leading to structural consolidation and strength enhancement.

  6. Evaluation of Polymer-Filler Interaction Characteristics by Force Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ratto, T; Saab, A

    2007-04-23

    Silicone polymers are frequently used as cushions and inserts between load bearing parts. In this capacity, they must act to position their associated parts and distribute mechanical force as appropriate. One type of failure is specific to silicones that are filled with high surface area particulates for purposes of tailoring the polymer compressive properties. Additives such as fumed silicon oxide are presumed to have a high degree of surface interaction with the polymer matrix, thus causing the polymer to stiffen and to display greater dimensional stability as a function of temperature. However, it has been observed that the compressive behavior of these materials is not always invariant over long times. There is evidence that suggests changes in humidity and temperature can irreversibly alter the silicone-filler interaction, thereby changing the overall characteristics of parts made from such materials. As before, changes in compressive or shear stability can have serious effects on the ability of these materials to effectively position precision parts or distribute high mechanical loads. We approach the analysis of the filled systems by creating controlled layers of silicone polymers attached to silicon oxide substrates. Straight chain vinyl-silicone polymers identical to those used in the formulation of pads for stockpile systems are chemically appended to a substrate surface, and cross-linked to form a three dimensional network. This type of structure serves as a model of silicone polymer coating a silicon oxide filler particle. We study these model systems first by using Atomic Force Microscopy (AFM) to image the samples with nanometer resolution, and then by measuring the forces of interactions between single model silica filler particles and polymer-coated surfaces. We use normal longitudinal force AFM to measure adhesion, and a relatively newly developed technique, lateral force AFM, to determine the frictional forces between the silica particles and the

  7. POLAR DISK GALAXY FOUND IN WALL BETWEEN VOIDS

    NARCIS (Netherlands)

    Stanonik, K.; Platen, E.; Aragon-Calvo, M. A.; van Gorkom, J. H.; van de Weygaert, R.; van der Hulst, J. M.; Peebles, P. J. E.

    2009-01-01

    We have found an isolated polar disk galaxy in what appears to be a cosmological wall situated between two voids. This void galaxy is unique as its polar disk was discovered serendipitously in an Hi survey of SDSS void galaxies, with no optical counterpart to the Hi polar disk. Yet the Hi mass in th

  8. POLAR DISK GALAXY FOUND IN WALL BETWEEN VOIDS

    NARCIS (Netherlands)

    Stanonik, K.; Platen, E.; Aragon-Calvo, M. A.; van Gorkom, J. H.; van de Weygaert, R.; van der Hulst, J. M.; Peebles, P. J. E.

    2009-01-01

    We have found an isolated polar disk galaxy in what appears to be a cosmological wall situated between two voids. This void galaxy is unique as its polar disk was discovered serendipitously in an Hi survey of SDSS void galaxies, with no optical counterpart to the Hi polar disk. Yet the Hi mass in th

  9. "Dark energy" in the Local Void

    CERN Document Server

    Villata, M

    2012-01-01

    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 ($\\sim5\\times10^{15}\\,M_\\odot$) 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 vo...

  10. Changes in pulp web properties by addition of natural filler

    Science.gov (United States)

    Kamaludin, Nurul Hasanah; Ghazali, Arniza; Daud, Wan Rosli Wan; Ghazali, Salmi

    2012-09-01

    Development of the desired pulp-based products eco-properties are governed by factors like choice and suitability of raw material, the design and operation of pulping process and choice of additives. Fines recovered during refining discharge of an alkaline peroxide pulping system were collected based on their retention on varying mesh-sizes screens. Analysis shows that 12% of the 400-mesh fines added to the web enhances paper tensile strength by 100%. This defines the usefulness of fibrillar particles whose cell wall collapsibility increases the web density by increasing bonding ability and thus, strength of pulp-based products such as paper. The study acknowledges fines functioning as natural filler in pulp network and collection of fines from the refining discharge was found to reduce 70% turbidity and this improvement will help reduce the costs pertinent to generation of whitewater from the pulping system.

  11. Autonomous selection of PDE inpainting techniques vs. exemplar inpainting techniques for void fill of high resolution digital surface models

    Science.gov (United States)

    Rahmes, Mark; Yates, J. Harlan; Allen, Josef DeVaughn; Kelley, Patrick

    2007-04-01

    High resolution Digital Surface Models (DSMs) may contain voids (missing data) due to the data collection process used to obtain the DSM, inclement weather conditions, low returns, system errors/malfunctions for various collection platforms, and other factors. DSM voids are also created during bare earth processing where culture and vegetation features have been extracted. The Harris LiteSite TM Toolkit handles these void regions in DSMs via two novel techniques. We use both partial differential equations (PDEs) and exemplar based inpainting techniques to accurately fill voids. The PDE technique has its origin in fluid dynamics and heat equations (a particular subset of partial differential equations). The exemplar technique has its origin in texture analysis and image processing. Each technique is optimally suited for different input conditions. The PDE technique works better where the area to be void filled does not have disproportionately high frequency data in the neighborhood of the boundary of the void. Conversely, the exemplar based technique is better suited for high frequency areas. Both are autonomous with respect to detecting and repairing void regions. We describe a cohesive autonomous solution that dynamically selects the best technique as each void is being repaired.

  12. Molecular Gas and Star Formation in Voids

    CERN Document Server

    Das, M; Iono, D; Honey, M; Ramya, S

    2014-01-01

    We present the detection of molecular gas using CO(1-0) line emission and follow up Halpha 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 under dense 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 Halpha line luminosities. CO(1--0) emission was detected in four galaxies and the derived molecular gas masses lie between (1 - 8)E+9 Msun. The H$\\alpha$ imaging observations of three galaxies detected in CO emission indicates ongoing star formation and the derived star forma...

  13. Standard guidelines for the use of dermal fillers

    Directory of Open Access Journals (Sweden)

    Vedamurthy Maya

    2008-03-01

    Full Text Available Currently used fillers vary greatly in their sources, efficacy duration and site of deposition; detailed knowledge of these properties is essential for administering them. Indications for fillers include facial lines (wrinkles, folds, lip enhancement, facial deformities, depressed scars, periocular melanoses, sunken eyes, dermatological diseases-angular cheilitis, scleroderma, AIDS lipoatrophy, earlobe plumping, earring ptosis, hand, neck, dιcolletι rejuvenation. Physicians′ qualifications : Any qualified dermatologist may use fillers after receiving adequate training in the field. This may be obtained either during postgraduation or at any workshop dedicated to the subject of fillers. The physicians should have a thorough knowledge of the anatomy of the area designated to receive an injection of fillers and the aesthetic principles involved. They should also have a thorough knowledge of the chemical nature of the material of the filler, its longevity, injection techniques, and any possible side effects. Facility: Fillers can be administered in the dermatologist′s minor procedure room. Preoperative counseling and informed consent: Detailed counseling with respect to the treatment, desired effects, and longevity of the filler should be discussed with the patient. Patients should be given brochures to study and adequate opportunity to seek information. Detailed consent forms need to be completed by the patients. A consent form should include the type of filler, longevity expected and possible postoperative complications. Preoperative photography should be carried out. Choice of the filler depends on the site, type of defect, results needed, and the physician′s experience. Injection technique and volume depend on the filler and the physician′s preference, as outlined in these guidelines.

  14. Mechanical stress in silicon nanosized architectures: Defects of SOD processed silica filler

    Energy Technology Data Exchange (ETDEWEB)

    Ricci, Pier Carlo, E-mail: carlo.ricci@dsf.unica.it [Dipartimento di Fisica, Università di Cagliari, s.p. n 8 Km 0.700, 09042 Monserrato, Cagliari (Italy); Casula, Riccardo [Dipartimento di Fisica, Università di Cagliari, s.p. n 8 Km 0.700, 09042 Monserrato, Cagliari (Italy); Gulleri, Gianluca; Fumagalli, Francesco [Micron Semiconductor Italia, s.r.l. via Camillo Olivetti, 2 20864 Agrate Brianza, MB (Italy); Carbonaro, Carlo Maria; Corpino, Riccardo [Dipartimento di Fisica, Università di Cagliari, s.p. n 8 Km 0.700, 09042 Monserrato, Cagliari (Italy)

    2014-07-25

    Highlights: • Structural and optical properties of silica filled STI architectures. • The silica filler induces a compressive stress. • PL spectra show a large distribution of emitting defects in the UV–blue. • The defects were identified and located at the silica–liner interface. - Abstract: The mechanical stress in nanosized silicon architectures is studied in shallow trench isolation systems with different liners and spin on dielectrics processed silica filler by means of Raman spectroscopy. The nanopatterning of silicon wafers causes a tensile stress of the system whereas the presence of the filler induces a compressive stress which depends on the interaction between silica filler and liner: by changing the liner from silicon dioxide to silicon nitride one can induce a larger compressive stress. The analysis of the ultraviolet excited emission properties in the visible range (nanosecond lasting bands at 2.5, 3.0 and 3.3 eV) allowed us to individuate and locate silica related defects and to correlate their presence to the induced compressive stress.

  15. 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 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...

  16. The Mechanism of Hydrogen-facilitating Initiation of Voids

    Institute of Scientific and Technical Information of China (English)

    褚武扬; 蒋兴钢; 肖纪美

    1994-01-01

    By combining the hydrogen-induced local plastic deformation theory with the decohesive theory and the hydrogen pressure theory, a new mechanism of hydrogen-facilitating initiation of voids has been proposed. Through facilitating the local plastic deformation and reducing the cohesive strength, hydrogen promotes both initiating a nanocrack and blunting the nanocrack into a void, resulting in hydrogen-promoting initiation of the void. On the other hand, hydrogen can enhance the stability of the void through reducing the cohesive strength and forming a hydrogen pressure in the void.

  17. The Void Galaxy Survey: Photometry, structure and identity of void galaxies

    CERN Document Server

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

    2016-01-01

    We analyze photometry from deep B-band images of 59 void galaxies in the Void Galaxy Survey (VGS), together with their near-infrared 3.6$\\mu$m and 4.5$\\mu$m Spitzer photometry. The VGS galaxies constitute a sample of void galaxies that were selected by a geometric-topological procedure from the SDSS DR7 data release, and which populate the deep interior of voids. Our void galaxies span a range of absolute B-magnitude from $\\rm{M_B=-15.5}$ to $\\rm{M_B=-20}$, while at the 3.6$\\mu$m band their magnitudes range from $\\rm{M_{3.6}=-18}$ to $\\rm{M_{3.6}=-24}$. Their B-[3.6] colour and structural parameters indicate these are star forming galaxies. A good reflection of the old stellar population, the near-infrared band photometry also provide a robust estimate of the stellar mass, which for the VGS galaxies we confirm to be smaller than $3 \\times 10^{10}$ M$_\\odot$. In terms of the structural parameters and morphology, our findings align with other studies in that our VGS galaxy sample consists mostly of small late-t...

  18. High filler concrete using fly ash. Chloride penetration and microstructure

    NARCIS (Netherlands)

    Valcke, S.L.A.; Polder, R.B.; Nijland, T.G.; Leegwater, G.A.; Visser, J.H.M.; Bigaj-van Vliet, A.J.

    2012-01-01

    Most high filler concrete studies are based on relatively high contents of powder (cement + filler) (>400 kg m-3). This paper aims to increase the total fly ash content relative to the clinker content, while simultaneously minimizing the total powder content in the concrete to values lower than 300

  19. 7 CFR 58.229 - Filler and packaging equipment.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Filler and packaging equipment. 58.229 Section 58.229....229 Filler and packaging equipment. All filling and packaging equipment shall be of sanitary... equipment should comply with the 3-A Sanitary Standards for equipment for Packaging Dry Milk and Dry...

  20. Bio-based fillers for environmentally friendly composites

    CSIR Research Space (South Africa)

    Mokhothu, Thabang H

    2017-03-01

    Full Text Available of Composites from Renewable Materials, Volume 1, Structure and Chemistry, p. 243-270 Bio-based Fillers for Environmentally Friendly Composites Thabang H. Mokhothu and Maya J. John ABSTRACT: The use of bio-based fillers as alternative replacement...

  1. Selecting fillers on emotional appearance improves lineup identification accuracy.

    Science.gov (United States)

    Flowe, Heather D; Klatt, Thimna; Colloff, Melissa F

    2014-12-01

    Mock witnesses sometimes report using criminal stereotypes to identify a face from a lineup, a tendency known as criminal face bias. Faces are perceived as criminal-looking if they appear angry. We tested whether matching the emotional appearance of the fillers to an angry suspect can reduce criminal face bias. In Study 1, mock witnesses (n = 226) viewed lineups in which the suspect had an angry, happy, or neutral expression, and we varied whether the fillers matched the expression. An additional group of participants (n = 59) rated the faces on criminal and emotional appearance. As predicted, mock witnesses tended to identify suspects who appeared angrier and more criminal-looking than the fillers. This tendency was reduced when the lineup fillers matched the emotional appearance of the suspect. Study 2 extended the results, testing whether the emotional appearance of the suspect and fillers affects recognition memory. Participants (n = 1,983) studied faces and took a lineup test in which the emotional appearance of the target and fillers was varied between subjects. Discrimination accuracy was enhanced when the fillers matched an angry target's emotional appearance. We conclude that lineup member emotional appearance plays a critical role in the psychology of lineup identification. The fillers should match an angry suspect's emotional appearance to improve lineup identification accuracy.

  2. A Cosmic Void Catalog of SDSS DR12 BOSS Galaxies

    Science.gov (United States)

    Mao, Qingqing; Berlind, Andreas A.; Scherrer, Robert J.; Neyrinck, Mark C.; Scoccimarro, Román; Tinker, Jeremy L.; McBride, Cameron K.; Schneider, Donald P.; Pan, Kaike; Bizyaev, Dmitry; Malanushenko, Elena; Malanushenko, Viktor

    2017-02-01

    We present a cosmic void catalog using the large-scale structure galaxy catalog from the Baryon Oscillation Spectroscopic Survey (BOSS). This galaxy catalog is part of the Sloan Digital Sky Survey (SDSS) Data Release 12 and is the final catalog of SDSS-III. We take into account the survey boundaries, masks, and angular and radial selection functions, and apply the ZOBOV void finding algorithm to the Galaxy catalog. We identify a total of 10,643 voids. After making quality cuts to ensure that the voids represent real underdense regions, we obtain 1,228 voids with effective radii spanning the range 20–100 {h}-1 {Mpc} and with central densities that are, on average, 30% of the mean sample density. We release versions of the catalogs both with and without quality cuts. We discuss the basic statistics of voids, such as their size and redshift distributions, and measure the radial density profile of the voids via a stacking technique. In addition, we construct mock void catalogs from 1000 mock galaxy catalogs, and find that the properties of BOSS voids are in good agreement with those in the mock catalogs. We compare the stellar mass distribution of galaxies living inside and outside of the voids, and find no large difference. These BOSS and mock void catalogs are useful for a number of cosmological and galaxy environment studies.

  3. 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.

  4. Filler particles used in dental biomaterials induce production and release of inflammatory mediators in vitro.

    Science.gov (United States)

    Ansteinsson, Vibeke E; Samuelsen, Jan Tore; Dahl, Jon E

    2009-04-01

    Although dental composites are in extensive use today, little is known about the biological effects of the filler particles. As composite materials are gradually broken down in the aggressive environment of the oral cavity, the filler particles may leak and induce toxic effects on the surrounding tissue and cells. The aim of this study was to elucidate possible adverse biological effects of commonly used dental filler particles; bariumaluminiumsilica (BaAlSi) and bariumaluminiumfluorosilica (BaAlFSi) with mean size of 1 microm. BEAS-2B cells were used as a model system. Particle morphology, mean particle size in solution, and particle surface charge were determined by scanning electron microscopy and Malvern zetasizer technology, respectively. Enzyme-linked immunosorbent assay was used to detect secretion of cytokine and chemokine (IL-8 and IL-6) and quantitative PCR for detection of gene activity. Both types of particle increased the release of IL-6 and IL-8 in a dose-dependent manner. BaAlFSi particles induced a more marked IL-8 response compared to BaAlSi particles, whereas no significant difference was observed for the IL-6 response. Mechanistic studies using specific inhibitors and activators indicated that cyclic AMP-dependent protein kinase A is partly involved in the observed IL-8 response. In conclusion, we consider dental filler particles to have potential to induce adverse biological response in cell cultures.

  5. Effect of Natural Fillers on Mechanical Properties of GFRP Composites

    Directory of Open Access Journals (Sweden)

    Vikas Dhawan

    2013-01-01

    Full Text Available Fiber reinforced plastics (FRPs have replaced conventional engineering materials in many areas, especially in the field of automobiles and household applications. With the increasing demand, various modifications are being incorporated in the conventional FRPs for specific applications in order to reduce costs and achieve the quality standards. The present research endeavor is an attempt to study the effect of natural fillers on the mechanical characteristics of FRPs. Rice husk, wheat husk, and coconut coir have been used as natural fillers in glass fiber reinforced plastics (GFRPs. In order to study the effect of matrix on the properties of GFRPs, polyester and epoxy resins have been used. It has been found that natural fillers provide better results in polyester-based composites. Amongst the natural fillers, in general, the composites with coconut coir have better mechanical properties as compared to the other fillers in glass/epoxy composites.

  6. EFFECT OF RICE HUSKS AS FILLER IN POLYMER MATRIX COMPOSITES

    Directory of Open Access Journals (Sweden)

    K. Hardinnawirda

    2012-06-01

    Full Text Available In this study, rice husk-filled polyester composites were produced with rice husks (RH as the filler and unsaturated polyester resin (UPR as the matrix. Several percentages of filler loadings were used (10, 15, 20 and 25 wt % in order to gain insights into the effect of filler content on the mechanical properties and water intake of the composites. The tensile strength of the RH-filled UPR composites was found to decrease as the filler loading increased; however, as it reached 25 wt %, the strength showed a moderate increase. The Young’s modulus showed a remarkable increase for 15 wt % of RH but decreased as the RH percentage increased further to 25 wt %. A water absorption test was conducted and the results showed that the composites absorb more water as the percentage weight of RH increased, which is attributed to the ability of the RH filler to absorb water.

  7. Microstructural Evolution of the Interface Between Pure Titanium and Low Melting Point Zr-Ti-Ni(Cu) Filler Metals

    Science.gov (United States)

    Lee, Dongmyoung; Sun, Juhyun; Kang, Donghan; Shin, Seungyoung; Hong, Juhwa

    2014-12-01

    Low melting point Zr-based filler metals with melting point depressants (MPDs) such as Cu and Ni elements are used for titanium brazing. However, the phase transition of the filler metals in the titanium joint needs to be explained, since the main element of Zr in the filler metals differs from that of the parent titanium alloys. In addition, since the MPDs easily form brittle intermetallics, that deteriorate joint properties, the phase evolution they cause needs to be studied. Zr-based filler metals having Cu content from 0 to 12 at. pct and Ni content from 12 to 24 at. pct with a melting temperature range of 1062 K to 1082 K (789 °C to 809 °C) were wetting-tested on a titanium plate to investigate the phase transformation and evolution at the interface between the titanium plate and the filler metals. In the interface, the alloys system with Zr, Zr2Ni, and (Ti,Zr)2Ni phases was easily changed to a Ti-based alloy system with Ti, Ti2Ni, and (Ti,Zr)2Ni phases, by the local melting of parent titanium. The dissolution depths of the parent metal were increased with increasing Ni content in the filler metals because Ni has a faster diffusion rate than Cu. Instead, slow diffusion of Cu into titanium substrate leads to the accumulation of Cu at the molten zone of the interface, which could form undesirable Ti x Cu y intermetallics. This study confirmed that Zr-based filler metals are compatible with the parent titanium metal with the minimum content of MPDs.

  8. The void galaxy survey: photometry, structure and identity of void galaxies

    Science.gov (United States)

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

    2017-01-01

    We analyse photometry from deep B-band images of 59 void galaxies in the Void Galaxy Survey (VGS), together with their near-infrared 3.6 μm and 4.5 μm Spitzer photometry. The VGS galaxies constitute a sample of void galaxies that were selected by a geometric-topological procedure from the Sloan Digital Sky Survey Data Release 7 data release, and which populate the deep interior of voids. Our void galaxies span a range of absolute B-magnitude from MB = -15.5 to -20, while at the 3.6 μm band their magnitudes range from M3.6 = -18 to -24. Their B-[3.6] colour and structural parameters indicate these are star-forming galaxies. A good reflection of the old stellar population, the near-infrared band photometry also provide a robust estimate of the stellar mass, which for the VGS galaxies we confirm to be smaller than 3 × 1010 M⊙. In terms of the structural parameters and morphology, our findings align with other studies in that our VGS galaxy sample consists mostly of small late-type galaxies. Most of them are similar to Sd-Sm galaxies, although a few are irregularly shaped galaxies. The sample even includes two early-type galaxies, one of which is an AGN. Their Sérsic indices are nearly all smaller than n = 2 in both bands and they also have small half-light radii. In all, we conclude that the principal impact of the void environment on the galaxies populating them mostly concerns their low stellar mass and small size.

  9. 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.

  10. Collapse of elongated voids in porous energetic materials: Effects of void orientation and aspect ratio on initiation

    Science.gov (United States)

    Rai, Nirmal Kumar; Schmidt, Martin J.; Udaykumar, H. S.

    2017-04-01

    The sensitivity of porous energetic materials depends on mesostructural heterogeneities such as voids, defects, cracks, and grain boundaries. The mesostructure of pressed explosives contains voids of arbitrary shapes including elongated voids of various orientations and aspect ratios. Mesoscale simulations to date have analyzed the effect of void morphology on the sensitivity of energetic materials for idealized shapes such as cylindrical, conical, and elliptical. This work analyzes the sensitivity behavior of elongated voids in an HMX matrix subject to shock loading. Simulations show that sensitivity of elongated voids depends strongly on orientation as well as aspect ratio. Ranges of orientations and aspects ratios are identified that enhance or inhibit initiation. Insights obtained from single elongated void analyses are used to identify sensitive locations in an imaged mesostructure of a pressed explosive sample.

  11. Void fraction prediction in saturated flow boiling

    Energy Technology Data Exchange (ETDEWEB)

    Francisco J Collado [Dpto de Ingenieria Mecanica-Motores Termicos, CPS-B, Universidad de Zaragoza, Maria de Luna 50018-Zaragoza (Spain)

    2005-07-01

    Full text of publication follows: An essential element in thermal-hydraulics is the accurate prediction of the vapor void fraction, or fraction of the flow cross-sectional area occupied by steam. Recently, the author has suggested to calculate void fraction working exclusively with thermodynamic properties. It is well known that the usual 'flow' quality, merely a mass flow rate ratio, is not at all a thermodynamic property because its expression in function of thermodynamic properties includes the slip ratio, which is a parameter of the process not a function of state. By the other hand, in the classic and well known expression of the void fraction - in function of the true mass fraction of vapor (also called 'static' quality), and the vapor and liquid densities - does not appear the slip ratio. Of course, this would suggest a direct procedure for calculating the void fraction, provided we had an accurate value of the true mass fraction of vapor, clearly from the heat balance. However the classic heat balance is usually stated in function of the 'flow' quality, what sounds really contradictory because this parameter, as we have noted above, is not at all a thermodynamic property. Then we should check against real data the actual relationship between the thermodynamic properties and the applied heat. For saturated flow boiling just from the inlet of the heated tube, and not having into account the kinetic and potential terms, the uniform applied heat per unit mass of inlet water and per unit length (in short, specific linear heat) should be closely related to a (constant) slope of the mixture enthalpy. In this work, we have checked the relation between the specific linear heat and the thermodynamic enthalpy of the liquid-vapor mixture using the actual mass fraction. This true mass fraction is calculated using the accurate measurements of the outlet void fraction taken during the Cambridge project by Knights and Thom in the sixties for

  12. Sub-micron free-standing metal slabs with dielectric nano-voids of arbitrary shapes embedded beneath atomically-flat surface.

    Science.gov (United States)

    Kho, Kiang Wei; Shen, Zexiang; Olivo, Malini

    2011-05-23

    Thin metal slabs with plasmonic nano-voids buried within the skin depth (slab. By artificially varying the topography of the capping metal surface from ultra-smooth to moderately-rough, we show structural symmetricity in a nano-void-metal system can render the overall plasmonic responses becoming profoundly influenced by the surface smoothness. The current fabrication technique is thus of primary importance to the preparation of any kind of smooth nano-void-passivated metal slabs.

  13. Plasticity size effects in voided crystals

    DEFF Research Database (Denmark)

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

    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...... 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)....

  14. Plasticity size effects in voided crystals

    DEFF Research Database (Denmark)

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

    2008-01-01

    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...... 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)....

  15. 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.

  16. The view from the boundary: a new void stacking method

    CERN Document Server

    Cautun, Marius; Frenk, Carlos S

    2015-01-01

    We introduce a new method for stacking voids and deriving their profile that greatly increases the potential of voids as a tool for precision cosmology. Given that voids are highly non-spherical and have most of their mass at their edge, voids are better described relative to their boundary rather than relative to their centre, as in the conventional spherical stacking approach. The boundary profile is obtained by computing the distance of each volume element from the void boundary. Voids can then be stacked and their profiles computed as a function of this boundary distance. This approach enhances the weak lensing signal of voids, both shear and convergence, by a factor of two when compared to the spherical stacking method. It also results in steeper void density profiles that are characterised by a very slow rise inside the void and a pronounced density ridge at the void boundary, in qualitative agreement with theoretical models of expanding spherical underdensities. The resulting boundary density profile i...

  17. Voids in Ly{\\alpha} Forest Tomographic Maps

    CERN Document Server

    Stark, Casey W; White, Martin; Lee, Khee-Gan

    2015-01-01

    We present a new method of finding cosmic voids using tomographic maps of Ly{\\alpha} forest flux. We identify cosmological voids with radii of 2 - 12 $h^{-1}$Mpc in a large N-body simulation at $z = 2.5$, and characterize the signal of the high-redshift voids in density and Ly{\\alpha} forest flux. The void properties are similar to what has been found at lower redshifts, but they are smaller and have steeper radial density profiles. Similarly to what has been found for low-redshift voids, the radial velocity profiles have little scatter and agree very well with the linear theory prediction. We run the same void finder on an ideal Ly{\\alpha} flux field and tomographic reconstructions at various spatial samplings. We compare the tomographic map void catalogs to the density void catalog and find good agreement even with modest-sized voids ($r > 6 \\, h^{-1}$Mpc). Using our simple void-finding method, the configuration of the ongoing CLAMATO survey covering 1 deg$^2$ would provide a sample of about 100 high-redshi...

  18. The sparkling Universe: the coherent motions of cosmic voids

    CERN Document Server

    Lambas, Diego G; Ceccarelli, Laura; Ruiz, Andrés N; Paz, Dante J; Maldonado, Victoria E; Luparello, Heliana E

    2015-01-01

    We compute the bulk motions of cosmic voids, using a $\\Lambda$CDM numerical simulation considering the mean velocities of the dark matter inside the void itself and that of the haloes in the surrounding shell. We find coincident values of these two measures in the range $\\sim$ 300-400 km/s, not far from the expected mean peculiar velocities of groups and galaxy clusters. When analysing the distribution of the pairwise relative velocities of voids, we find a remarkable bimodal behaviour consistent with an excess of both systematically approaching and receding voids. We determine that the origin of this bimodality resides in the void large scale environment, since once voids are classified into void-in-void (R-type) or void-in-cloud (S-type), R-types are found mutually receding away, while S-types approach each other. The magnitude of these systematic relative velocities account for more than 100 km/s, reaching large coherence lengths of up to 200 h$^{-1}$ Mpc . We have used samples of voids from the Sloan Digi...

  19. 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.

  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 Void Galaxy Survey: Galaxy Evolution and Gas Accretion in Voids

    NARCIS (Netherlands)

    Kreckel, Kathryn; van Gorkom, Jacqueline H.; Beygu, Burcu; van de Weijgaert, Marinus; van der Hulst, J. M.; Aragon-Calvo, Miguel A.; Peletier, Reynier F.

    2014-01-01

    Voids represent a unique environment for the study of galaxy evolution, as the lower density environment is expected to result in shorter merger histories and slower evolution of galaxies. This provides an ideal opportunity to test theories of galaxy formation and evolution. Imaging of the neutral h

  2. The Void Galaxy Survey: Galaxy Evolution and Gas Accretion in Voids

    CERN Document Server

    Kreckel, Kathryn; Beygu, Burcu; van de Weygaert, Rien; van der Hulst, J M; Aragon-Calvo, Miguel A; Peletier, Reynier F

    2014-01-01

    Voids represent a unique environment for the study of galaxy evolution, as the lower density environment is expected to result in shorter merger histories and slower evolution of galaxies. This provides an ideal opportunity to test theories of galaxy formation and evolution. Imaging of the neutral hydrogen, central in both driving and regulating star formation, directly traces the gas reservoir and can reveal interactions and signs of cold gas accretion. For a new Void Galaxy Survey (VGS), we have carefully selected a sample of 59 galaxies that reside in the deepest underdensities of geometrically identified voids within the SDSS at distances of ~100 Mpc, and pursued deep UV, optical, Halpha, IR, and HI imaging to study in detail the morphology and kinematics of both the stellar and gaseous components. This sample allows us to not only examine the global statistical properties of void galaxies, but also to explore the details of the dynamical properties. We present an overview of the VGS, and highlight key re...

  3. The Void Galaxy Survey: Morphology and Star Formation Properties of Void Galaxies

    CERN Document Server

    Beygu, B; van der Hulst, J M; Peletier, R; Jarrett, T; van de Weygaert, R; van Gorkom, J H; Aragón-Calvo, M

    2015-01-01

    We present the structural and star formation properties of 59 void galaxies as part of the Void Galaxy Survey (VGS). Our aim is to study in detail the physical properties of these void galaxies and study the effect of the void environment on galaxy properties. We use Spitzer 3.6 $\\rm{\\mu m}$ and B-band imaging to study the morphology and color of the VGS galaxies. For their star formation properties, we use Halpha and GALEX near-UV imaging. We compare our results to a range of galaxies of different morphologies in higher density environments. We find that the VGS galaxies are in general disk dominated and star forming galaxies. Their star formation rates are, however, often less than 1 $\\rm{M_{\\odot}}$ $\\rm{yr^{-1}}$. There are two early-type galaxies in our sample as well. In $\\rm{r_{e}}$ versus $\\rm{M_{B}}$ parameter space, VGS galaxies occupy the same space as dwarf irregulars and spirals.

  4. The Void Galaxy Survey: Star Formation Properties

    CERN Document Server

    Beygu, B; 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 $\\rm{H\\alpha}$ and recent star formation rates from near-UV imaging. In addition, infrared 3.4 $\\rm{\\mu m}$, 4.6 $\\rm{\\mu m}$, 12 $\\rm{\\mu m}$ and 22 $\\rm{\\mu m}$ WISE emission is used as star formation and mass indicator. Infrared and optical colours show that the VGS sample displays a wide range of dust and metallicity properties. We combine these measurements with stellar and HI masses to measure the specific SFRs ($\\rm{SFR/M_{*}}$) and star formation efficiencies ($\\rm{SFR/M_{HI}}$). We compare the star formation properties of our sample with galaxies in the more moderate density regions of the cosmic web, 'the field'. We find that specific SFRs of the VGS galaxies as a function of stellar and HI mass are similar to those of the galaxies in these field regions. Their $\\rm{SFR\\alpha}$ is slightly elevated than the galaxies in the field for a given total HI mass. ...

  5. Structural dynamics and interfacial properties of filler-reinforced elastomers

    Energy Technology Data Exchange (ETDEWEB)

    Fritzsche, J; Klueppel, M, E-mail: Manfred.Klueppel@DIKautschuk.de [Deutsches Institut fuer Kautschuktechnologie e V, Eupener Strasse 33, D-30519 Hannover (Germany)

    2011-01-26

    The combined effect of filler networking and reduced chain mobility close to the filler interface is analyzed based on investigations of the relaxation dynamics of a solution of styrene butadiene rubber filled with different loadings and types of nanostructured carbon blacks. Dynamic-mechanical and dielectric spectra are studied in a wide frequency and temperature range. By referring to a tunneling process of charge carriers over nanoscopic gaps between adjacent carbon black particles the gap distance is evaluated from the dielectric spectra. This distance corresponds to the length of glassy-like polymer bridges forming flexible bonds between adjacent filler particles of the filler network. It is found that the gap distance decreases with increasing filler loading and specific surface area which correlates with an increase of the apparent activation energy of the filler network evaluated from dynamic-mechanical data. Due to the thermal activation of glassy-like polymer bridges the time-temperature superposition principle is not fulfilled for filled elastomers and the introduction of vertical shift factors is necessary to obtain viscoelastic master curves. The change in the low frequency viscoelastic properties by the incorporation of fillers is shown to be related to the superimposed dynamics of the filler network governed by the viscoelastic response of the glassy-like polymer bridges. This effect is distinguished from the reduced chain mobility close to the filler surface which results in a broadening of the glass transition on the high temperature or low frequency side. The microstructure-based interpretation of viscoelastic data is supported by an analysis of the relaxation time spectra.

  6. Structural dynamics and interfacial properties of filler-reinforced elastomers

    Science.gov (United States)

    Fritzsche, J.; Klüppel, M.

    2011-01-01

    The combined effect of filler networking and reduced chain mobility close to the filler interface is analyzed based on investigations of the relaxation dynamics of a solution of styrene butadiene rubber filled with different loadings and types of nanostructured carbon blacks. Dynamic-mechanical and dielectric spectra are studied in a wide frequency and temperature range. By referring to a tunneling process of charge carriers over nanoscopic gaps between adjacent carbon black particles the gap distance is evaluated from the dielectric spectra. This distance corresponds to the length of glassy-like polymer bridges forming flexible bonds between adjacent filler particles of the filler network. It is found that the gap distance decreases with increasing filler loading and specific surface area which correlates with an increase of the apparent activation energy of the filler network evaluated from dynamic-mechanical data. Due to the thermal activation of glassy-like polymer bridges the time-temperature superposition principle is not fulfilled for filled elastomers and the introduction of vertical shift factors is necessary to obtain viscoelastic master curves. The change in the low frequency viscoelastic properties by the incorporation of fillers is shown to be related to the superimposed dynamics of the filler network governed by the viscoelastic response of the glassy-like polymer bridges. This effect is distinguished from the reduced chain mobility close to the filler surface which results in a broadening of the glass transition on the high temperature or low frequency side. The microstructure-based interpretation of viscoelastic data is supported by an analysis of the relaxation time spectra.

  7. Influence of Filler Metals in Welding Wires on the Phase and Chemical Composition of Weld Metal

    Science.gov (United States)

    Kozyrev, N. A.; Osetkovskiy, I. V.; Kozyreva, O. A.; Zernin, E. A.; Kartsev, D. S.

    2016-04-01

    The influence of filler metals used in welding wires on the phase and chemical composition of the metal, which is surfaced to mining equipment exposed to abrasive wear, has been investigated. Under a laboratory environment, samples of Mo-V-B and Cr-Mn-Mo-V wires were made. The performed experiments have revealed that fillers of the Cr-Mn-Mo-V system used in powder wire show better wear resistance of the weld metal than that of the Mn-Mo-V-B system; the absence of boron, which promotes grain refinement in the Mn-Mo-V-B system, significantly reduces wear resistance; the Mn-Mo-V-B weld metal has a finer structure than the Cr-Mn-Mo-V weld metal.

  8. Ductile damage of porous materials with two populations of voids

    Science.gov (United States)

    Vincent, Pierre-Guy; Monerie, Yann; Suquet, Pierre

    2008-01-01

    This study is devoted to the modelling of ductile damage in uranium dioxide. This polycrystalline material contains two populations of voids of well separated size. The problem addressed here is the prediction of the effective flow surface of a Gurson material containing randomly oriented oblate voids. The case of spherical voids is considered first and the variational approach of Gurson is generalized by adding a compressible component to his original velocity field. The case of aligned oblate voids is then considered and a suitable generalization of a velocity field due to Gologanu et al. (ASME J. Engrg. Mater. Technol. 116 (1994) 290-297) is proposed. The extension to randomly oriented voids is achieved by averaging over all orientations. In each case, rigorous upper bounds and approximate estimates are derived and compared (in the case of spherical voids) with Finite Element simulations. To cite this article: P.-G. Vincent et al., C. R. Mecanique 336 (2008).

  9. Voids and the Cosmic Web: cosmic depressions & spatial complexity

    CERN Document Server

    van de Weygaert, Rien

    2016-01-01

    Voids form a prominent aspect of the Megaparsec distribution of galaxies and matter. Not only do they represent a key constituent of the Cosmic Web, they also are one of the cleanest probes and measures of global cosmological parameters. The shape and evolution of voids are highly sensitive to the nature of dark energy, while their substructure and galaxy population provides a direct key to the nature of dark matter. Also, the pristine environment of void interiors is an important testing ground for our understanding of environmental influences on galaxy formation and evolution. In this paper, we review the key aspects of the structure and dynamics of voids, with a particular focus on the hierarchical evolution of the void population. We demonstrate how the rich structural pattern of the Cosmic Web is related to the complex evolution and buildup of voids.

  10. Void alignment and density profile applied to measuring cosmological parameters

    CERN Document Server

    Dai, De-Chang

    2015-01-01

    We study the orientation and density profiles of the cosmological voids with SDSS10 data. Using voids to test Alcock-Paczynski effect has been proposed and tested in both simulations and actual SDSS data. Previous observations imply that there exist an empirical stretching factor which plays an important role in the voids' orientation. Simulations indicate that this empirical stretching factor is caused by the void galaxies' peculiar velocities. Recently Hamaus et al. found that voids' density profiles are universal and their average velocities satisfy linear theory very well. In this article we first confirm that the stretching effect exists using independent analysis. We then apply the universal density profile to measure the cosmological parameters. We find that the void density profile can be a tool to measure the cosmological parameters.

  11. Experimental study of the effect of void reactivity feedback on the behavior of the scaled model boiling water reactor

    Science.gov (United States)

    Meftah, Khaled

    A Scaled Model Boiling Water Reactor (SMBWR) model uses low pressure (i.e., 0.095 MPa) water in a heated channel 0.5 meters in length with four electrically heated fuel simulator rods. The axial void profile in the channel is measured using conductivity probes and the power to the heaters is modulated according to the void fraction to simulate void reactivity feedback. The steam from the heated channel is passed through a valve that reduces the pressure to 0.012 MPa where the steam is condensed in conditions similar to those found in a conventional BWR condenser. The feedwater flow rate, heater power, and instrumentation in the facility are controlled and monitored through a Quadra 950 computer running LabVIEW software. The void fraction signals are analyzed to identify the different flow regimes and determine the vapor velocity in the SMBWR channel using features of the probability density function and power spectral density. The void coefficient of reactivity is modified in the BWR scale model through the LabVIEW interface and the effect on the behavior of the channel is directly observed. The system response is reported for abrupt stepwise pressure changes and abrupt stepwise power changes. The response is typical of that expected for a BWR. The void reactivity feedback effect is also examined by analyzing the frequency response of the channel void fraction at steady state.

  12. Research on Alkaline Filler Flame-Retarded Asphalt Pavement

    Institute of Scientific and Technical Information of China (English)

    HU Shuguang; ZHANG Houji; WANG Jiaolan

    2006-01-01

    Used as flame retardant of tunnel asphalt pavement, organic bromides produce a large amount of poisons and smoke in construction and flame retardation stage. The alkaline filler was found to replace mineral filler, and the flame-retarded asphalt mixtures were produced. Experimental results show that these asphalt mixtures are smoke restrained; the performances and construction technology of asphalt pavement are not influenced; also the alkaline filler is of low-price. So this kind of flame-retarded asphalt mixtures is suitable for tunnel pavement.

  13. Peculiarities of Shape Recovery in Polymer Composites with Compacting Filler

    Directory of Open Access Journals (Sweden)

    V. A. Beloshenko

    2011-01-01

    Full Text Available Peculiarities of the shape memory effect development in composites based on the epoxy polymer and various fillers, such as thermoexpanded graphite, aerosils, metallized graphite, and basalt flakes, have been investigated. It has been determined that straining followed by the shape recovery of composites is accompanied by changes in their volume. Extent and character of the changes depend on the ability of fillers to compaction under pressure, deformation scheme, adsorption ability of the filler. It is shown that the combined deformation consisting of compression and stretching of specimens in different sequence gives structural states for which the longitudinal strain-transverse strain ratio can take zero, positive, or negative values.

  14. Advanced Laser Techniques for Filler-Induced Complications

    DEFF Research Database (Denmark)

    Cassuto, D.; Marangoni, O.; Santis, G. De

    2009-01-01

    BACKGROUND The increasing use of injectable fillers has been increasing the occurrence of disfiguring anaerobic infection or granulomas. This study presents two types of laser-assisted evacuation of filler material and inflammatory and necrotic tissue that were used to treat disfiguring facial...... nodules after different types of gel fillers. MATERIALS AND METHODS Infectious lesions after hydrogels were drained using a lithium triborate laser at 532 nm, with subsequent removal of infected gel and pus (laser assisted evacuation). Granuloma after gels containing microparticles were treated using...

  15. Transparent Gap Filler Solution over a DVB-RCS2 Satellite Platform in a Railway Scenario: Performance Evaluation Study

    Directory of Open Access Journals (Sweden)

    Peppino Fazio

    2015-01-01

    Full Text Available In this work, a performance study of a system equipped with a transparent Gap Filler solution in a DVB-RCS2 satellite platform has been provided. In particular, a simulation model based on a 3-state Markov chain, overcoming the blockage status through the introduction of a transparent Gap Filler (using devices on both tunnel sides has been implemented. The handover time, due to switching mechanism between satellite and Gap Filler, has been taken into account. As reference scenario, the railway market has been considered, which is characterized by a N-LOS condition, due to service disruptions caused by tunnels, vegetation and buildings. The system performance, in terms of end-to-end delay, queue size and packet loss percentage, have been evaluated, in order to prove the goodness of communications in a real railroad path.

  16. Void-induced dissolution in molecular dynamics simulations of NaCl and water.

    Science.gov (United States)

    Bahadur, Ranjit; Russell, Lynn M; Alavi, Saman; Martin, Scot T; Buseck, Peter R

    2006-04-21

    To gain a better understanding of the interaction of water and NaCl at the surface during dissolution, we have used molecular dynamics to simulate the interface with two equal-sized slabs of solid NaCl and liquid water in contact. The introduction of voids in the bulk of the salt, as well as steps or pits on the surface of the NaCl slab results in a qualitative change of system structure, as defined by radial distribution functions (RDFs). As an example, the characteristic Na-Na RDF for the system changes from regularly spaced narrow peaks (corresponding to an ordered crystalline structure), to a broad primary and smaller secondary peak (corresponding to a disordered structure). The change is observed at computationally short time scales of 100 ps, in contrast with a much longer time scale of 1 mus expected for complete mixing in the absence of defects. The void fraction (which combines both bulk and surface defects) required to trigger dissolution varies between 15%-20% at 300 K and 1 atm, and has distinct characteristics for the physical breakdown of the crystal lattice. The void fraction required decreases with temperature. Sensitivity studies show a strong dependence of the critical void fraction on the quantity and distribution of voids on the surface, with systems containing a balanced number of surface defects and a rough surface showing a maximum tendency to dissolve. There is a moderate dependence on temperature, with a 5% decrease in required void fraction with a 100 K increase in temperature, and a weak dependence on water potential model used, with the SPC, SPC/E, TIP4P, and RPOL models giving qualitatively identical results. The results were insensitive to the total quantity of water available for dissolution and the duration of the simulation.

  17. Void-induced dissolution in molecular dynamics simulations of NaCl and water

    Science.gov (United States)

    Bahadur, Ranjit; Russell, Lynn M.; Alavi, Saman; Martin, Scot T.; Buseck, Peter R.

    2006-04-01

    To gain a better understanding of the interaction of water and NaCl at the surface during dissolution, we have used molecular dynamics to simulate the interface with two equal-sized slabs of solid NaCl and liquid water in contact. The introduction of voids in the bulk of the salt, as well as steps or pits on the surface of the NaCl slab results in a qualitative change of system structure, as defined by radial distribution functions (RDFs). As an example, the characteristic Na-Na RDF for the system changes from regularly spaced narrow peaks (corresponding to an ordered crystalline structure), to a broad primary and smaller secondary peak (corresponding to a disordered structure). The change is observed at computationally short time scales of 100ps, in contrast with a much longer time scale of 1μs expected for complete mixing in the absence of defects. The void fraction (which combines both bulk and surface defects) required to trigger dissolution varies between 15%-20% at 300K and 1atm, and has distinct characteristics for the physical breakdown of the crystal lattice. The void fraction required decreases with temperature. Sensitivity studies show a strong dependence of the critical void fraction on the quantity and distribution of voids on the surface, with systems containing a balanced number of surface defects and a rough surface showing a maximum tendency to dissolve. There is a moderate dependence on temperature, with a 5% decrease in required void fraction with a 100K increase in temperature, and a weak dependance on water potential model used, with the SPC, SPC/E, TIP4P, and RPOL models giving qualitatively identical results. The results were insensitive to the total quantity of water available for dissolution and the duration of the simulation.

  18. Thermal Systems and Materials Testing

    Science.gov (United States)

    Aguirre, Nathan

    2010-01-01

    During my internship, I was involved in Boeing Thermal System/M&P, which handles maintenance and repairs of shuttle tiles, blankets, gap fillers, etc. One project I took part in was the revision of TPS-227, a repair process to tiles that entailed drilling out tile damage and using a cylindrical insert to fill the hole. The previous specification used minimal adhesive for application and when the adhesive cured, there would be several voids in the adhered material, causing an unsatisfactory bond. The testing compared several new methods and I analyzed the number of voids produced by each method to determine which one was most effective at eliminating void space. We revised the original process to apply a light adhesive coat to the top 25% of the borehole and a heavy coat to 100% of the insert. I was also responsible for maintaining the subnominal bond database, which records all unsatisfactory SIP (Strain Isolator Pad) bonds. I then archived each SIP physically for future referral data and statistics. In addition, I performed post-flight tile inspections for damages and wrote dispositions to have these tiles repaired. This also included writing a post-flight damage report for a section of Atlantis and creating summarized repair process guidelines for orbiter technicians.

  19. A model for shape memory alloys with the possibility of voids

    CERN Document Server

    Fremond, Michel

    2009-01-01

    The paper is devoted to the study of a mathematical model for the thermomechanical evolution of metallic shape memory alloys. The main novelty of our approach consists in the fact that we include the possibility for these materials to exhibit voids during the phase change process. Indeed, in the engineering paper has been recently proved that voids may appear when the mixture is produced by the aggregations of powder. Hence, the composition of the mixture varies (under either thermal or mechanical actions) in this way: the martensites and the austenite transform into one another whereas the voids volume fraction evolves. The first goal of this contribution is hence to state a PDE system capturing all these modelling aspects in order then to establish the well-posedness of the associated initial-boundary value problem.

  20. 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.

  1. An observational detection of the bridge effect of void filaments

    CERN Document Server

    Shim, Junsup; Hoyle, Fiona

    2015-01-01

    The bridge effect of void filaments is a phrase coined by Park & Lee (2009b) to explain the correlations found in a numerical experiment between the luminosity of the void galaxies and the degree of the straightness of their host filaments. Their numerical finding implies that a straight void filament provides a narrow channel for the efficient transportation of gas and matter particles from the surroundings into the void galaxies. To observationally confirm the presence of the bridge effect of void filaments, we identify the filamentary structures from the Sloan void catalog and determine the specific size of each void filament as a measure of its straightness. Using both classical and Bayesian statistics, we indeed detect a strong tendency that the void galaxies located in the more straight filaments are on average more luminous, which is in agreement with the numerical prediction. It is also shown that the strength of correlation increases with the spatial extent of the void filaments, which can be phy...

  2. 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.

  3. On de-Sitter Geometry in Cosmic Void Statistics

    CERN Document Server

    Gibbons, Gary W; Yoshida, Naoki; Chon, Sunmyon

    2013-01-01

    Starting from the geometrical concept of a 4-dimensional de-Sitter configuration of spheres in Euclidean 3-space and modelling voids in the Universe as spheres, we show that a uniform distribution over this configuration space implies a power-law for the void number density which is consistent with results from the excursion set formalism and from data, for an intermediate range of void volumes. We also discuss the effect of restricting the survey geometry on the void statistics. This work is a new application of de-Sitter geometry to cosmology and also provides a new geometrical perspective on self-similarity in cosmology.

  4. The sparkling Universe: a scenario for cosmic void motions

    CERN Document Server

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

    2015-01-01

    We perform a statistical study of the global motion of cosmic voids using both a numerical simulation and observational data. We analyse their relation to large--scale mass flows and the physical effects that drive those motions. We analyse the bulk motions of voids, defined by the mean velocity of haloes in the surrounding shells in the numerical simulation, and by galaxies in the Sloan Digital Sky Survey Data Release 7. We find void mean bulk velocities close to 400 km/s, comparable to those of haloes (~ 500-600 km/s), depending on void size and the large--scale environment. Statistically, small voids move faster than large ones, and voids in relatively higher density environments have higher bulk velocities than those placed in large underdense regions. Also, we analyze the mean mass density around voids finding, as expected, large--scale overdensities (underdensities) along (opposite to) the void motion direction, suggesting that void motions respond to a pull--push mechanism. This contrasts with massive ...

  5. New Statistical Perspective to The Cosmic Void Distribution

    CERN Document Server

    Pycke, Jean-Renaud

    2016-01-01

    In this study, we obtain the size distribution of voids as a 3-parameter redshift independent log-normal void probability function (VPF) directly from the Cosmic Void Catalog (CVC). Although many statistical models of void distributions are based on the counts in randomly placed cells, the log-normal VPF that we here obtain is independent of the shape of the voids due to the parameter-free void finder of the CVC. We use three void populations drawn from the CVC generated by the Halo Occupation Distribution (HOD) Mocks which are tuned to three mock SDSS samples to investigate the void distribution statistically and the effects of the environments on the size distribution. As a result, it is shown that void size distributions obtained from the HOD Mock samples are satisfied by the 3-parameter log-normal distribution. In addition, we find that there may be a relation between hierarchical formation, skewness and kurtosis of the log-normal distribution for each catalog. We also show that the shape of the 3-paramet...

  6. A study of process induced voids in resistance welding of thermoplastic composites

    OpenAIRE

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

    2015-01-01

    Void formation in resistance welding of woven fabric reinforced thermoplastic composites was investigated. Void contents were measured using optical microscopy and digital image process. Un-even void distributions were observed in the joints, and more voids were found in the middle of the joints than the edges. A higher welding pressure was shown to help reduce the void generation. The mechanisms of void formation, in particular fibre de-compaction induced voids and residual moisture induced ...

  7. Use of Cellulose-Containing Fillers in Composites with Polypropylene

    Directory of Open Access Journals (Sweden)

    Marianna LAKA

    2011-07-01

    Full Text Available The composites, containing recycled polypropylene and fillers, obtained from different lignocellulosics by the thermocatalytic destruction method, were investigated. Birch sawdust, newsprint wastes, cotton residues and wood bleached sulphate pulp were used as raw materials for obtaining fillers. The indices of mechanical properties (tensile strength, modulus of elasticity, deformation at break, shear modulus, toughness, twisting moment of the composites' samples were determined. It has been found that the obtained composites have relatively good mechanical properties. Better results were obtained, using fillers from sawdust and wood pulp. After treating the fillers with rapeseed oil, their water vapour sorption and water retention value (WRV decreased. In this case, the strength of the composites was higher.http://dx.doi.org/10.5755/j01.ms.17.2.484

  8. Microstructural and rheological analysis of fillers and asphalt mastics

    Science.gov (United States)

    Geber, R.; Simon, A.; Kocserha, I.; Buzimov, A.

    2017-01-01

    Pavements are made of different grades of mineral aggregates and organic binder. The aggregates are sorted in different sizes and different amount which are mixed together with bitumen. The finest mineral fraction (ddolomite) which are used in Hungarian road constructions with the use of different techniques (particle size distribution, scanning electronmicroscopy tests, mercury intrusion porosimetry, BET specific surface tests, determination of hydrophobicity). After the tests of fillers, asphalt mastics were prepared and rheological examinations were obtained. These examinations served to observe the interaction and the effect of fillers. The stiffening effect of fillers and the causes of rutting were also investigated. Based on our results, it can be stated that particle size, hydrophobic properties and the amount of fillers highly affect the rheological properties of mastics.

  9. Behaviour of voids in a shear field

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    2009-01-01

    to a plane connecting the ends of the micro-crack is used as an approximate representation of contact stresses during frictionless sliding. In a previous study of the same problem the author applied hydrostatic pressure inside the nearly closed micro-crack to approximate contact conditions. The transverse...... surface loads used in the present analyses avoid the tendency to unrealistically elongate the voids. It is found that even though the model applied here gives significantly later occurrence of a maximum overall shear stress than that found by using hydrostatic pressure, the present model does predict...... a maximum in all the cases analyzed and thus illustrates the micro-mechanism leading to failure of the material by localization of plastic flow....

  10. 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

  11. Microscopic air void analysis of hardened Portland cement concrete by the isolated shadow technique

    Science.gov (United States)

    Harris, Basil Mark

    The Isolated Shadow Technique is an image processing and analysis procedure for identifying and characterizing surface voids dispersed on an otherwise flat plane of heterogeneous solids. The objective of the Isolated Shadow Technique is to capture, process, and analyze images of a flat surface in which all of the features, save the boundary outlines of any surface voids, are eliminated. In short, the technique utilizes a series of digital images of the subject planar surface; where each image of the series is subjected to a unique lighting condition. By positioning the lights such that the shadows cast into the craters vary between images, these variations can be sequestered and the edges of the voids can subsequently be reconstructed from the isolated shadows. The primary purpose of this work was the development of the Isolated Shadow Technique for the particular application of quantitatively describing the microscopic voids in hardened Portland cement concrete. The Isolated Shadow System was developed for this application of the technique. The hardware and software of the system are described and the function is demonstrated. The system was found to have an average accuracy of 2.7% with a maximum deviation of 5.0% when compared to physical measurements. The results of polished sections of concrete specimens characterized by the Isolated Shadow System are compared to the results obtained with the commonly used standard methods (ASTM C 457; A and B). The coefficients of variation of parameters calculated to describe the air-void system (according to the ASTM C 457 formulations) are shown to be in the neighborhood of one percent when the observed test area includes at least 7,830 mmsp2 of polished concrete (with paste contents ranging from approximately 28% to 32%). The sensitivity of the air-void system parameters (as computed by the system) to changes in magnification and mosaic size are evaluated. A critical analysis of the underlying assumptions of the ASTM C

  12. Natural Rubber-Filler Interactions: What Are the Parameters?

    Science.gov (United States)

    Chan, Alan Jenkin; Steenkeste, Karine; Canette, Alexis; Eloy, Marie; Brosson, Damien; Gaboriaud, Fabien; Fontaine-Aupart, Marie-Pierre

    2015-11-17

    Reinforcement of a polymer matrix through the incorporation of nanoparticles (fillers) is a common industrial practice that greatly enhances the mechanical properties of the composite material. The origin of such mechanical reinforcement has been linked to the interaction between the polymer and filler as well as the homogeneous dispersion of the filler within the polymer matrix. In natural rubber (NR) technology, knowledge of the conditions necessary to achieve more efficient NR-filler interactions is improving continuously. This study explores the important physicochemical parameters required to achieve NR-filler interactions under dilute aqueous conditions by varying both the properties of the filler (size, composition, surface activity, concentration) and the aqueous solution (ionic strength, ion valency). By combining fluorescence and electron microscopy methods, we show that NR and silica interact only in the presence of ions and that heteroaggregation is favored more than homoaggregation of silica-silica or NR-NR. The interaction kinetics increases with the ion valence, whereas the morphology of the heteroaggregates depends on the size of silica and the volume percent ratio (dry silica/dry NR). We observe dendritic structures using silica with a diameter (d) of 100 nm at a ∼20-50 vol % ratio, whereas we obtain raspberry-like structures using silica with d = 30 nm particles. We observe that in liquid the interaction is controlled by the hydrophilic bioshell, in contrast to dried conditions, where hydrophobic polymer dominates the interaction of NR with the fillers. A good correlation between the nanoscopic aggregation behavior and the macroscopic aggregation dynamics of the particles was observed. These results provide insight into improving the reinforcement of a polymer matrix using NR-filler films.

  13. ACID-BASE INTERACTIONS BETWEEN POLYMERS AND FILLERS

    Institute of Scientific and Technical Information of China (English)

    WANG Qingguo; CHEN Fute; HUANG Yuanfu; ZHOU Qingli

    1987-01-01

    Inverse gas chromatography(IGC) and Fourier-transform infrared (FT-IR) techniques were applied to determining the relative acid-base strength of polymers and coupling agents. The acid-base characteristics of fillers such as CaCO3 could be altered by treatment with different coupling agents. It was shown that some mechanical properties of filled polymers were obviously associated with acid-base interactions between polymers and fillers.

  14. Influence of silanization and filler fraction on aged dental composites.

    Science.gov (United States)

    Lin, C T; Lee, S Y; Keh, E S; Dong, D R; Huang, H M; Shih, Y H

    2000-11-01

    The effect of silanization and filler fraction on the mechanical properties of aged dental composites was investigated. Experimental composites (75/25 Bis-GMA/TEGDMA resin reinforced with 0, 12.6, 30.0, and 56.5 vol% 8 microm silanized/unsilanized BaSiO6) were fabricated into 4.7 mm diameter x 2.2 mm thick discs and 3.5 mm diameter x 7.3 mm thick discs for diametral tensile and compressive tests, respectively. The effect of immersion in 75% ethanol at 37 degrees C for 0-30 days on the diametral tensile strength (DTS) and compressive strength (CS) of the samples was evaluated and analysed by ANOVA and Tukey LSD test. The fracture interface between filler and resin matrix was then examined by scanning electron microscope. Results and subsequent statistical evidence from DTS (18.6+/-7.6 MPa, silanized versus 11.7+/-2.6 MPa, unsilanized) and CS (85.1+/-29.7 MPa, silanized versus 56.0+/-11.3 MPa, unsilanized) strongly implies that silanization may greatly enhance the mechanical properties of the resin composites. Furthermore, it also shows that both DTS and CS increased proportionally as the filler fraction of the composites increased. However, in the unsilanized groups, DTS decreased (up to 40%) as the filler fraction increased, and CS showed no relevance to the filler fraction at all. As for the influence of aging, it was found that both DTS and CS showed a significant decrease after immersion in 75% ethanol, and silanization heavily correlated with the filler fraction of aged-resin composites. Microscopic examination of the fractured samples showed that failure primarily occurred within the resin matrix per se for silanized composites and adjacent to the filler particles for unsilanized composites. All the evidence points to the conclusion that mechanical properties of aged-resin composites can be greatly influenced by silanization and the filler fraction.

  15. Mechanical and Morphological Properties of Nano Filler Polyester Composites

    Directory of Open Access Journals (Sweden)

    Bonnia Noor Najmi

    2016-01-01

    Full Text Available This research is focusing on mechanical and morphological properties of unsaturated polyester (UP reinforced with two different types of filler which is nano size clay Cloisite 30B (C30B and Carbon Black (CB. Samples were fabricated via hand lay-up and open molding technique. Percentages of Cloisite 30B & Carbon Black (CB used vary from 0, 2, 4, 6, 8 and 10 wt%. The mechanical properties were evaluated by impact, flexural and hardness testing. Result shows that the mechanical strength of C30B was better compare to CB filled composite. The combination of UP with C30B helps to improve the properties due to the high surface area of nanosize filler in the matrix. The result shows that increasing of filler content had increased mechanical properties of composites. Optimum percentage represent good mechanical properties are 4% for both fillers. SEM images showed that rough surface image indicate to agglomeration of filler in the matrix for CB sample and smooth surface image on C30B sample indicate to homogenous blending between filler and matrix polyester. SEM images proved that mechanical properties result indicate that C30B polyester composite is a good reinforcement compare to CB polyester composite.

  16. Wear of nanofilled dental composites at varying filler concentrations.

    Science.gov (United States)

    Lawson, Nathaniel C; Burgess, John O

    2015-02-01

    The aim of this study is to examine the effects of nanofiller concentration on the mechanisms of wear of a dental composite. Nanofilled composites were fabricated with a bisphenol A glycidyl methacrylate polymer and 40 nm SiO2 filler particles at three filler loads (25, 50, and 65 wt %). The elastic modulus, flexural strength, and hardness of the composites and the unfilled resin were measured. The materials (n = 8) were tested in the modified wear testing device at 50,000, 100,000, and 200,000 cycles with 20N force at 1 Hz. A 33% glycerine lubricant and stainless steel antagonist were used. The worn composite and antagonist surfaces were analyzed with noncontact profilometry and SEM. The volumetric wear data indicated that there are significant differences between filler concentrations and cycles (p composites. Increasing filler content increased hardness and modulus and increased flexural strength up to 50% fill. SEM evaluation of the worn specimens indicated that the resin and 25% filled materials exhibited cracking and failed by fatigue and the 50 and 65% filled materials exhibited microcutting and failed by abrasive wear. Based on the results of this study, composite manufacturers are recommended to use a filler concentration between 25 and 50% when using nanosized filler particles. © 2014 Wiley Periodicals, Inc.

  17. Analysis of filler particle levels and sizes in dental alginates

    Directory of Open Access Journals (Sweden)

    Hugo Lemes Carlo

    2010-06-01

    Full Text Available The aim of this study was to determine the inorganic filler fractions and sizes of commercially alginates. The inorganic particles volumetric fractions of five alginates - Jeltrate(J, Jeltrate Plus(JP, Jeltrate Chromatic Ortho(JC, Hydrogum(H and Ezact Krom(E were accessed by weighing a previously determined mass of each material in water before and after burning samples at 450 °C for 3 hours. Unsettled materials were soaked in acetone and chloroform and sputter-coated with gold for SEM evaluation of fillers' morphology and size. The results for the volumetric inorganic particle content were (%: J - 48.33, JP - 48.33, JC - 33.79, H - 37.55 and E - 40.55. The fillers presented a circular appearance with helical form and various perforations. Hydrogum fillers looked like cylindrical, perforated sticks. The mean values for fillers size were (μm: J - 12.91, JP - 13.67, JC - 13.44, E - 14.59 and H - 9 (diameter, 8.81 (length. The results of this study revealed differences in filler characteristics that could lead to different results when testing mechanical properties.

  18. Evaluation of Hydrated Lime Filler in Asphalt Mixtures

    Directory of Open Access Journals (Sweden)

    Mohammed Abbas Hasan Al-Jumaily

    2008-01-01

    Full Text Available Mineral filler is one of important materials and affecting on properties and quality of asphalt mixtures .There are different types of mineral filler depended on cost and quality , the matter encourages us to achieve this study to evaluate hydrated lime filler effects on properties of asphalt mixes related with strength and durability. Conventional asphaltic concrete mixtures with Portland cement and soft sandstone fillers and mixtures modified with hydrated lime were evaluated for their fundamental engineering properties as defined by Marshall properties , index of retained strength , indirect tensile strength , permanent deformation characteristics , and fatigue resistance .A typical dense graded mixture employed in construction of surface course pavement in Iraq in accordance with SCRB specifications was used .The materials used in this study included mineral aggregate materials (coarse and fine sizes were originally obtained from Najaf Sea quarries and two grades of asphalt cements produced from Daurah refinery which are D47 and D66 . The physical properties , stiffness modulus and chemical composition are evaluated for the recovered asphalt cement from prepared asphalt mixes containing various filler types .The paper results indicated that the addition of hydrated lime as mineral filler improved the permanent deformation characteristics and fatigue life and the use of hydrated lime will decrease the moisture susceptibility of the asphalt mixtures.

  19. Carbon dioxide selective mixed matrix composite membrane containing ZIF-7 nano-fillers

    KAUST Repository

    Li, Tao

    2013-01-01

    Mixed matrix materials made from selective inorganic fillers and polymers are very attractive for the manufacturing of gas separation membranes. But only few of these materials could be manufactured into high-performance asymmetric or composite membranes. We report here the first mixed matrix composite membrane made of commercially available poly (amide-b-ethylene oxide) (Pebax®1657, Arkema) mixed with the nano-sized zeolitic imidazole framework ZIF-7. This hybrid material has been successfully deposited as a thin layer (less than 1μm) on a porous polyacrylonitrile (PAN) support. An intermediate gutter layer of PTMSP was applied to serve as a flat and smooth surface for coating to avoid polymer penetration into the porous support. Key features of this work are the preparation and use of ultra-small ZIF-7 nano-particles (around 30-35nm) and the membrane processability of Pebax®1657. SEM pictures show that excellent adhesion and almost ideal morphology between the two phases has been obtained simply by mixing the as-synthesized ZIF-7 suspension into the Pebax®1657 dope, and no voids or clusters can be observed. The performance of the composite membrane is characterized by single gas permeation measurement of CO2, N2 and CH4. Both, permeability (PCO2 up to 145barrer) and gas selectivity (CO2/N2 up to 97 and CO2/CH4 up to 30) can be increased at low ZIF- loading. The CO2/CH4 selectivity can be further increased to 44 with the filler loading of 34wt%, but the permeability is reduced compared to the pure Pebax®1657 membrane. Polymer chain rigidification at high filler loading is supposed to be a reason for the reduced permeability. The composite membranes prepared in this work show better performance in terms of permeance and selectivity when compared with asymmetric mixed matrix membranes described in the recent literature. Overall, the ZIF 7/Pebax mixed matrix membranes show a high performance for CO2 separation from methane and other gas streams. They are easy to

  20. Measuring the growth rate of structure around cosmic voids

    Science.gov (United States)

    Hawken, A. J.; Michelett, D.; Granett, B.; Iovino, A.; Guzzo, L.

    2016-10-01

    Using an algorithm based on searching for empty spheres we identified 245 voids in the VIMOS Public Extragalactic Redshift Survey (VIPERS). We show how by modelling the anisotropic void-galaxy cross correlation function we can probe the growth rate of structure.

  1. A Cosmic Void Catalog of SDSS DR12 BOSS Galaxies

    CERN Document Server

    Mao, Qingqing; Scherrer, Robert J; Scoccimarro, Roman; Tinker, Jeremy L; McBride, Cameron K; Neyrinck, Mark C; Schneider, Donald P; Pan, Kaike; Bizyaev, Dmitry; Malanushenko, Elena; Malanushenko, Viktor

    2016-01-01

    We present a cosmic void catalog using the large-scale structure galaxy catalog from the Baryon Oscillation Spectroscopic Survey (BOSS). This galaxy catalog is part of the Sloan Digital Sky Survey (SDSS) Data Release 12 and is the final catalog of SDSS-III. We take into account the survey boundaries, masks, and angular and radial selection functions, and apply the ZOBOV void finding algorithm to the galaxy catalog. After making quality cuts to ensure that the voids represent real underdense regions, we identify 1228 voids with effective radii spanning the range 20-100Mpc/h and with central densities that are, on average, 30% of the mean sample density. We discuss the basic statistics of voids, such as their size and redshift distributions, and measure the radial density profile of the voids via a stacking technique. In addition, we construct mock void catalogs from 1000 mock galaxy catalogs, and find that the properties of BOSS voids are in good agreement with those in the mock catalogs. We compare the stella...

  2. Tensor anisotropy as a tracer of cosmic voids

    CERN Document Server

    Bustamante, Sebastian

    2015-01-01

    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 fractional anisotropy. 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/overcompansated depending on the absence/presence of an overdense matter ridge in their density profile, finding that close to $65\\%$ and $35\\%$ of the total population are classified into each category, respectively. Finally, we find evidence ...

  3. The relationship between void waves and flow regime transition

    Energy Technology Data Exchange (ETDEWEB)

    Lahey, R.T. Jr.; Drew, D.A.; Kalkach-Navarro, S.; Park, J.W.

    1992-12-31

    The results of an extensive experimental and analytical study on the relationship between void waves and flow regime transition are presented, in particular, the bubbly/slug flow regime transition. It is shown that void wave instability signals a flow regime transition.

  4. Voided stain on paper method for analysis of mouse urination.

    Science.gov (United States)

    Sugino, Y; Kanematsu, A; Hayashi, Y; Haga, H; Yoshimura, N; Yoshimura, K; Ogawa, O

    2008-01-01

    To evaluate the usefulness of a quantification method using filter paper for analyzing minute voided urine of the mouse. Voided stain on paper (VSOP) method; the correlation between area of stained spot on a filter paper and amount of applied liquid was calculated. Voiding behavior of the mice was analyzed by placing the animal above the same filter paper and recording voided time and area over 2 hr. The usefulness of the VSOP method was tested in analysis of the voiding behavior of five female 7-week-old ddY mice treated with cyclophosphamide (CPM, 150 mg/kg, intraperitoneally) and five control ones, in comparison with the histology of CPM-induced cystitis. Further, the voided volume of male and female ddY mouse ranging from 2 to 13 weeks was assessed. There was a linear correlation between liquid volume and stained area on the filter paper (y = 16.472x - 22.411, R(2) = 0.9981). Between control mice and those with histologically proven CPM cystitis, there was a significant difference in voided volume (362.7 +/- 51.9 and 127.8 +/- 100.0 microl, VSOP method is a useful tool for evaluating voiding behavior of the mouse, including those with small bladder capacity.

  5. 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 natu

  6. 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.

  7. High gain durable anti-reflective coating with oblate voids

    Energy Technology Data Exchange (ETDEWEB)

    Maghsoodi, Sina; Brophy, Brenor L.; Colson, Thomas E.; Gonsalves, Peter R.; Abrams, Ze' ev

    2016-06-28

    Disclosed herein are single layer transparent coatings with an anti-reflective property, a hydrophobic property, and that are highly abrasion resistant. The single layer transparent coatings contain a plurality of oblate voids. At least 1% of the oblate voids are open to a surface of the single layer transparent coatings.

  8. The Aspen-Amsterdam void finder comparison project

    NARCIS (Netherlands)

    Colberg, Joerg M.; Pearce, Frazer; Foster, Caroline; Platen, Erwin; Brunino, Riccardo; Neyrinck, Mark; Basilakos, Spyros; Fairall, Anthony; Feldman, Hume; Gottloeber, Stefan; Hahn, Oliver; Hoyle, Fiona; Mueller, Volker; Nelson, Lorne; Plionis, Manolis; Porciani, Cristiano; Shandarin, Sergei; Vogeley, Michael S.; van de Weygaert, Rien

    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

  9. Locating voids beneath pavement using pulsed electromagnetic waves

    Science.gov (United States)

    Steinway, W. J.; Echard, J. D.; Luke, C. M.

    1981-11-01

    The feasibility of using pulsed electromagnetic wave technology for locating and sizing voids beneath reinforced and nonreinforced portland cement concrete pavements is determined. The data processing techniques developed can be implemented to provide information for void depth and sizing to + or - 1/2 in. and spatial location within + or - 6 in. A very short pulse radar directly connected to a microcomputer was chosen as the equipment necessary to obtain measurements. This equipment has the required accuracy and reliability, and is a cost effective solution for the void locating problem. The radar provides a signal return from voids that has unique characteristics that can be examined to provide information regarding the location, depth, and shape of the void. The microcomputer provides a means of real time processing to extract the information from the radar signal return and record the results. Theoretical modeling of signal returns from voids led to suitable techniques for locating and sizing voids beneath the pavement. Analysis and application of these techniques to radar measurements verified the theoretical predictions that radar can be used to determine the location, size, and shape of actual voids.

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

    CERN Document Server

    Yang, Lin F; Aragon-Calvo, Miguel A; 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 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, the initial-conditions smoothing increases, and the number of voids and subvoids is suppressed. Also, void density profiles change, their shapes become flatter inside the void radius, while edges of the voids remain unchanged. Also, filaments and walls become cleaner, as the sub-structures in be...

  11. Space charge behaviour in an epoxy resin: the influence of fillers, temperature and electrode material

    Energy Technology Data Exchange (ETDEWEB)

    Gallot-Lavallee, O [Laboratoire de Genie Electrique de Toulouse, Universite Paul Sabatier-118, Route de Narbonne, Toulouse 31062 (France); Teyssedre, G [Laboratoire de Genie Electrique de Toulouse, Universite Paul Sabatier-118, Route de Narbonne, Toulouse 31062 (France); Laurent, C [Laboratoire de Genie Electrique de Toulouse, Universite Paul Sabatier-118, Route de Narbonne, Toulouse 31062 (France); Rowe, S [Direction des Recherches Materiaux, Schneider Electric SA-20, Rue Henri Tarze, Grenoble 38050 (France)

    2005-06-21

    This study aims to characterize the behaviour of the space charge in an epoxy resin used as electrical insulation in systems such as transformers and bus bars. Temperature, field level, filler content and nature of the electrodes are the parameters that were considered. Space charge measurements were performed using the pulsed electro acoustic technique, in a range of field and temperature up to 40 kV mm{sup -1} and 72 deg. C, respectively, on gold-coated and un-coated samples. We discuss the possibility of performing space charge measurement on filled epoxy resin despite the piezoelectricity of quartz fillers. Under dc field we observed a quasi-symmetrical build-up of homocharges at both electrodes, followed by a substitution of the homocharges by heterocharges, mainly close to the cathode. In addition, we recorded the space charge behaviour just before breakdown on a filled sample at 72 deg. C under 12 kV mm{sup -1}.

  12. Properties of natural rubber/attapulgite composites prepared by latex compounding method: Effect of filler loading

    Energy Technology Data Exchange (ETDEWEB)

    Muttalib, Siti Nadzirah Abdul, E-mail: sitinadzirah.amn@gmail.com; Othman, Nadras, E-mail: srnadras@usm.my; Ismail, Hanafi, E-mail: ihanafi@usm.my [School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, Seri Ampangan, 14300 Nibong Tebal, Pulau Pinang (Malaysia)

    2015-07-22

    This paper reports on the effect of filler loading on properties of natural rubber (NR)/attapulgite (ATP) composites. The NR/ATP composites were prepared by latex compounding method. It is called as masterbatch. The masterbatch was subsequently added to the NR through melt mixing process. The vulcanized NR/ATP composites were subjected to mechanical, swelling and morphological tests. All the results were compared with NR/ATP composites prepared by conventional system. The composites from masterbatch method showed better results compared to composites prepared by conventional method. They have higher tensile properties, elongation at break and tear strength. The images captured through scanning electron microscopy test revealed the improvement of tensile strength in masterbatch NR/ATP composites. It can be seen clearly that masterbatch NR/ATP have better filler dispersion compared to conventional method NR/ATP composites.

  13. Friction and wear of HNBR with different fillers under dry rolling and sliding conditions

    Directory of Open Access Journals (Sweden)

    2009-02-01

    Full Text Available Peroxide cured hydrogenated acrylonitrile/butadiene rubber (HNBR compounds with 20 parts per hundred rubber (phr active fillers, such as carbon black (CB, multiwall carbon nanotube (MWCNT and silica were produced and their friction and wear properties under unlubricated rolling and sliding conditions were evaluated. The network-related properties of the HNBR compounds were deduced from dynamic-mechanical thermal analysis (DMTA. The coefficient of friction (COF and the specific wear rate (Ws were determined in different home-made test rigs. The CB and MWCNT containing HNBR compounds exhibited the best resistance to rolling and sliding wear, respectively, among the HNBR systems studied. The worn surfaces were inspected in scanning electron microscope (SEM and the wear mechanisms were analyzed and discussed in respect to the types of wear and fillers.

  14. Arcjet Tests of Different Gap-Filler Options for the Orion PICA Heatshield

    Science.gov (United States)

    Skokova, Kristina; Ellerby, Donald; Blosser, Max; Venkatapathy, Ethiraj; Bouslog, Stan; Reuther, James

    2009-01-01

    PICA (Phenolic Infiltrated Carbon Ablator) is one of the candidate thermal protection materials for the Orion vehicle. Because PICA is fabricated in blocks, gaps exist between the blocks, similar to the individual ceramic tiles of the Shuttle thermal protection system. The results of this work focus on arcjet test results of different gap-filler options for PICA, performed as part of the Orion TPS Advanced Development Project. The arcjet tests were performed at NASA Ames Research Center on stagnation models 4 inches in diameter at conditions representative of Orion flight conditions for both Lunar and Low Earth Orbit return. Performance of gap-filler options was evaluated based on the extent of backface temperature change, as compared to PICA without gaps, and on the extent of flow penetration into the gap, evident from the gap opening and widening.

  15. Dislocation and void segregation in copper during neutron irradiation

    DEFF Research Database (Denmark)

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

    1986-01-01

    High-purity (99. 999%) and fully annealed copper specimens have been irradiated in the DR-3 reactor at Riso to doses of 1 multiplied by 10**2**2 and 5 multiplied by 10**2**2 neutrons (fast)m** minus **2(2 multiplied by 10** minus **3 dpa and 1 multiplied by 10** minus **2 dpa, respectively...... were distributed between these walls. The dislocation walls were practically free of voids and generally had a void-denuded zone along them. The density of dislocations (loops and segments) was very low in the region containing voids (i. e. between the dislocation walls). Even with this low dislocation...... 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....

  16. Alignment of galaxy spins in the vicinity of voids

    CERN Document Server

    Slosar, Anze

    2008-01-01

    We provide limits on the alignment of galaxy orientations with the direction to the void center for galaxies lying near the edges of voids. We locate spherical voids in volume limited samples of galaxies from the Sloan Digital Sky Survey using the HB inspired void finder and investigate the orientation of (color selected) spiral galaxies that are nearly edge-on or face-on. In contrast with previous literature, we find no statistical evidence for departure from random orientations. Expressed in terms of the parameter c, introduced by Lee & Pen to describe the strength of such an alignment, we find that c<0.11(0.13) at 95% (99.7%) confidence limit within a context of a toy model that assumes a perfectly spherical voids with sharp boundaries.

  17. Two new methods to detect cosmic voids without density measurements

    CERN Document Server

    Elyiv, Andrii; Pollina, Giorgia; Baldi, Marco; Branchini, Enzo; Cimatti, Andrea; Moscardini, Lauro

    2014-01-01

    Cosmic voids are effective cosmological probes to discriminate among competing world models. Their precise and unbiased identification is a prerequisite to perform accurate observational tests. The identification is generally based on density or geometry criteria that, because of their very nature, are prone to shot noise errors. In this work we propose two new void finders that are based on dynamical and clustering criteria to select voids in the Lagrangian coordinates and minimise the impact of sparse sampling. The first approach exploits the Zeldovich approximation to trace back in time the orbits of galaxies located in the voids and their surroundings, whereas the second uses the observed galaxy-galaxy correlation function to relax the objects' spatial distribution to homogeneity and isotropy. In both cases voids are defined as regions of the negative velocity divergence in Lagrangian coordinates, that can be regarded as sinks of the back-in-time streamlines of the mass tracers. To assess the performance ...

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

    Science.gov (United States)

    van de Weygaert, Rien

    2016-10-01

    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 nature of dark energy, while their substructure and galaxy population provides a direct key to thenature of dark matter. Also, the pristine environment of void interiors is an important testing groundfor our understanding of environmental influences on galaxy formation and evolution. In this paper, we reviewthe key aspects of the structure and dynamics ofvoids, with a particular focus on the hierarchical evolution of the void population. We demonstratehow the rich structural pattern of the Cosmic Web is related to the complex evolution and buildupof voids.

  19. Magneto-rheological response of elastomer composites with hybrid-magnetic fillers

    Science.gov (United States)

    Aloui, Sahbi; Klüppel, Manfred

    2015-02-01

    We study the magneto-rheological response of hybrid-magnetic elastomer composites consisting of two different magnetic filler particles at fixed overall concentration. Thereby, we focus on an optimization of mechanical and magnetic properties by combining highly reinforcing magnetic nano-particles (MagSilica) with micro-sized carbonyl-iron particles (CIP), which exhibit high switch ability in a magnetic field. We observe a symbiotic interaction of both filler types, especially in the case when an orientation of the magnetic filler particles is achieved due to curing in an external magnetic field. The orientation effect is significant only for the micro-sized CIP particles with high saturation magnetization, indicating that the induced magnetic moment for the nano-sized particles is too small for delivering sufficient attraction between the particles in an external magnetic field. A pronounced switching behavior is observed for the non-cross-linked melts with 15 and 20 vol.% CIP, whereby the small strain modulus increases by more than 50%. For the sample without the coupling agent silane, one even observes a relative modulus increase of about 140%, which can be related to the combined effect of a higher mobility of the particles without a silane layer and the ability of the particles to come in close contact when they are arranged in strings along the field lines. For the cross-linked samples, a maximum switching effect of about 30% is achieved for the system with pure CIP. This magneto-sensitivity decreases successively if CIP is replaced by MagSilica, while the tensile strength of the systems increases significantly. The use of silane reduces the switching effect, but it is necessary for a good mechanical performance by delivering strong chemical bonding of the magnetic filler particles to the polymer matrix.

  20. Garlic powder and wheat bran as fillers: Their effect on the physicochemical properties of edible biocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Fama, Lucia [Physics Department, School of Exact and Natural Sciences, University of Buenos Aires (UBA) and CONICET, Ciudad Universitaria, (1428) Buenos Aires (Argentina); Bittante, Ana Monica B.Q.; Sobral, Paulo J.A. [Food Engineering Department, FZEA, University of Sao Paulo, PO Box 23, 13635-900 Pirassununga (SP) (Brazil); Goyanes, Silvia [Physics Department, School of Exact and Natural Sciences, University of Buenos Aires (UBA) and CONICET, Ciudad Universitaria, (1428) Buenos Aires (Argentina); Gerschenson, Lia N., E-mail: lia@di.fcen.uba.ar [Industry Department, School of Exact and Natural Sciences, University of Buenos Aires (UBA) and CONICET, Ciudad Universitaria, (1428) Buenos Aires (Argentina)

    2010-07-20

    Biocomposites with two different fillers, garlic and wheat bran, were studied. They were based on cassava starch and contained glycerol as a plasticizer and potassium sorbate as an antimicrobial agent and were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and infrared spectroscopy (IR). The mechanical performance at room and lower temperatures was also studied. SEM micrographies of fractured surfaces of the wheat bran composite films showed some ruptured particles of fiber while fibrils of garlic on the order of nanometers were observed when garlic composite films were studied. Mechanical tests, at room temperature, showed that the addition of wheat bran led to an increment in the storage modulus (E') and hardening and a decrease in Tan {delta}, while the garlic composite showed a diminishing in the E' and hardening and did not produce significant changes in Tan {delta} values when compared with systems without fillers (matrix). In the range between -90 deg. C and 20 deg. C, all the materials studied presented two peaks in the Tan {delta} curve. In the case of the wheat bran composite, both relaxation peaks shifted slightly to higher temperatures, broadened and diminished their intensity when compared with those of the matrix; however garlic composite showed a similar behavior to the matrix. DSC thermograms of aqueous systems showed a slight shift of gelatinization temperature (T{sub gelatinization}) to higher values when the fillers were present. Thermograms of films showed that both, garlic and wheat bran composites, had a lower melting point than the matrix. IR data indicated that interaction between starch and fillers determined an increase in the availability of hydroxyl groups to be involved in a dynamic exchange with water.

  1. POLYMER FILLER INTERACTIONS IN POLY(VINYL CHLORIDE) FILLED WITH GLASS-BEADS - EFFECT OF GRAFTED POLY(METHYL METHACRYLATE)

    NARCIS (Netherlands)

    FOLKERSMA, R; CHALLA, G; SCHOUTEN, AJ

    1992-01-01

    Adhesion between filler and matrix has been studied using a model system composed of glass bead filled poly(vinyl chloride) (PVC). Stress-strain and volume-strain tests and scanning electron microscopy revealed that adhesion is improved by grafting poly(methyl methacrylate) (PMMA), which is known to

  2. Development of a new bin filler for apple harvesting and infield sorting with a review of existing technologies

    Science.gov (United States)

    The bin filler, which receives apples from the sorting system and then places them in the bin evenly without causing bruise damage, plays a critical role for the self-propelled apple harvest and infield sorting (HIS) machine that is being developed in our laboratory. Two major technical challenges ...

  3. Polymer-filler interactions in poly(vinyl chloride) filled with glass beads : effect of grafted poly(methyl methacrylate)

    NARCIS (Netherlands)

    Boven, Gert; Folkersma, Rudy; Challa, Ger; Schouten, Arend Jan; Bosma, Martin

    1992-01-01

    Adhesion between filler and matrix has been studied using a model system composed of glass bead filled poly(vinyl chloride) (PVC). Stress-strain and volume-strain tests and scanning electron microscopy revealed that adhesion is improved by grafting poly(methyl methacrylate) (PMMA), which is known to

  4. 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.

  5. FILLER ENGINEERING FOR PAPERMAKING: COMPARISION WITH FIBER ENGINEERING AND SOME IMPORTANT RESEARCH TOPICS

    Directory of Open Access Journals (Sweden)

    Jing Shen

    2010-05-01

    Full Text Available Fibers and fillers are important raw materials for the preparation of paper products. Similar to fiber engineering, filler engineering for papermaking has become an active research area. There are similarities as well as differences between engineering involving each of these classes of materials. There are differences in such aspects as the nature of materials to be engineered, applicable engineering methods, and engineerablity of the material surfaces. The co-development of fiber engineering and filler engineering can potentially provide many benefits to the papermaking industry. For filler engineering, the relevant research topics broadly can include fibrous filler engineering, hollow/porous filler engineering, acid-stabilization of calcium carbonate fillers, surface encapsulation of naturally occurring polymers or their derivatives, preflocculation, precoagulation, cationic modification, filler/size hybrid formation, organic filler engineering, using combinations of different types of available fillers, multilayer deposition modification, modification with polymer latexes or dispersants, physical modification, mechanical modification, surface functionalization, fines-filler composite/hybrids or fiber-filler composite/ hybrid formation, in-situ polymerization modification, surface grafting, physical treatment in the presence of polymeric additives, filler precipitation, and core-shell composite filler engineering.

  6. Properties of hydrogen induced voids in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Weber, J; Fischer, T; Hieckmann, E; Hiller, M; Lavrov, E V [Institute for Applied Physics/Semiconductor Physics, TU Dresden, 01062 Dresden (Germany)

    2005-06-08

    After heat treatment, silicon samples implanted with high doses of hydrogen exhibit blistering and defoliation of thin silicon layers. The process is used commercially in the fabrication of thin silicon-on-insulator layers (Smart Cut(registered)). In the present study we investigate the behaviour of hydrogen after different processing steps, which lead to thin Si layers bonded to glass substrates. A set of hydrogen implanted samples is studied by means of low temperature photoluminescence, Raman spectroscopy, x-ray diffraction and optical microscopy (visible and infrared). The formation of Si-H bonds is detected after implantation together with a build-up of internal strain. After annealing, the relaxation of the implanted layers is found to be connected with the formation of hydrogen saturated vacancies and the formation of H{sub 2} molecules filling up larger voids. A comparison is made with hydrogen plasma treated samples, where well defined platelets on {l_brace}111{r_brace} planes are found to trap hydrogen molecules. No direct evidence of the role of {l_brace}111{r_brace} and {l_brace}100{r_brace} platelets in the blistering process is found in the implanted layers from our study. We determine considerable compressive stresses in the bonded Si layers on glass substrates. The photoluminescence is strongly enhanced in these bonded layers but red-shifted due to a strain reduced band gap.

  7. Radionuclide voiding cystography in intrarenal reflux detection

    Energy Technology Data Exchange (ETDEWEB)

    Rizzoni, G.; Perale, R.; Bui, F.; Pitter, M.; Pavanello, L.; Boscolo, R.; Passerini Glazel, G.; Macri, C.

    1986-01-01

    In order to evaluate the possibility of detecting intra-renal reflux (IRR) with a more sensitive procedure, 48 children with recurrent urinary tract infections underwent intravenous urography (IVU) and voiding cystourethrogram (VCU) using a solution containing contrast medium and sup(99m)Tc-sulfur colloid particles which are known to persist in the renal parenchyma for a long time. Scintigraphic images were taken at 5 and 20 hours after VCU. 18 children had no vesico-ureteral reflux, 11 showed unilateral and 19 bilateral VUR, which was therefore present in 49 renal units. Among the 49 renal refluxing units (RRUs) IRR was detected radiologically in 8; of these isotopic activity in the renal area was present in all 6 RRUs who were examined at 20 hours. Of the remaining 41 RRUs with no radiologically detectable IRR 24 were evaluated at 20 hours and 5 (21%) showed renal radioactivity. Renal scars were significantly more frequent in kidneys with radioisotopic activity at 20 hours. The results of this study indicate that radionuclide cystography using sup(99m)Tc-sulfur colloid is a reliable procedure for demonstrating IRR, and to this end is more sensitive than X-ray VCU. Radionuclide cystography with sulfur colloid particles should therefore be considered a simple and useful complementary procedure, which is more sensitive than X-ray VCU in the diagnosis and follow-up of IRR.

  8. Utilization of bagasse and coconut fibers waste as fillers of sandwich composite for bridge railway sleepers

    Science.gov (United States)

    Soehardjo, K. A.; Basuki, A.

    2017-07-01

    The bridge railway sleepers is an essential component in the construction of railways, as the foundation of the rail support in order to withstand the load a train that runs above it. Sleepers used in bridge construction are expected to have a longer service life, lighter weight and durable so that can be used more efficient. This research was carried out to create a model of bridges railway sleepers made of sandwich structured composite from fiber glass, epoxy resin with fillers waste of bagasse (sugar cane pulp mill) or coconut fiberboard (copra industry) that using polyurethane as an adhesive. The process of making was conditioned for small and medium industrial applications. Railway sleepers’ specifications adapted to meet the requirements of end user. The process steps in this research include; lay-up fiberglass combined with bagasse/coconut fiberboard (as fillers), gluing with epoxy resin, molded it with pressure to be solid, curing after solidification process. The specimens of composite, bagasse and coconut fiber board were tested for tensile and compressive strength. The prototype were tested of mechanical test: flexural moment test to the stand rail, flexural moment test to the middle of the sleepers and tensile strength test on one side of the sleepers, in accordance to SNI 11-3388-1994 Method testing of single block concrete sleepers and bearing single rail fastening systems. The results of mechanical testing all variations meet the technical specifications of end user such as test results for flexural moment on all prototypes, after load test, there is no visible crack. While in the tensile strength test, it seem the prototype with coconut fiberboard filler, shows better performance than bagasse fiberboard filler, the decisions is just depended on techno economic and lifetime.

  9. High Density Polyethylene Composites Reinforced with Hybrid Inorganic Fillers: Morphology, Mechanical and Thermal Expansion Performance

    Directory of Open Access Journals (Sweden)

    Birm-June Kim

    2013-09-01

    Full Text Available The effect of individual and combined talc and glass fibers (GFs on mechanical and thermal expansion performance of the filled high density polyethylene (HDPE composites was studied. Several published models were adapted to fit the measured tensile modulus and strength of various composite systems. It was shown that the use of silane-modified GFs had a much larger effect in improving mechanical properties and in reducing linear coefficient of thermal expansion (LCTE values of filled composites, compared with the use of un-modified talc particles due to enhanced bonding to the matrix, larger aspect ratio, and fiber alignment for GFs. Mechanical properties and LCTE values of composites with combined talc and GF fillers varied with talc and GF ratio at a given total filler loading level. The use of a larger portion of GFs in the mix can lead to better composite performance, while the use of talc can help lower the composite costs and increase its recyclability. The use of 30 wt % combined filler seems necessary to control LCTE values of filled HDPE in the data value range generally reported for commercial wood plastic composites. Tensile modulus for talc-filled composite can be predicted with rule of mixture, while a PPA-based model can be used to predict the modulus and strength of GF-filled composites.

  10. Scaling of voids and fractality in the galaxy distribution

    CERN Document Server

    Gaite, J; Gaite, Jose; Manrubia, Susanna C.

    2002-01-01

    We study here, from first principles, what properties of voids are to be expected in a fractal point distribution and how the void distribution is related to its morphology. We show this relation in various examples and apply our results to the distribution of galaxies. If the distribution of galaxies forms a fractal set, then this property results in a number of scaling laws to be fulfilled by voids. Consider a fractal set of dimension $D$ and its set of voids. If voids are ordered according to decreasing sizes (largest void has rank R=1, second largest R=2 and so on), then a relation between size $\\Lambda$ and rank of the form $\\Lambda (R) \\propto R^{-z}$ must hold, with $z = d/D$, and where $d$ is the euclidean dimension of the space where the fractal is embedded. The physical restriction $D 1$ in a fractal set. The average size $\\bar \\Lambda$ of voids depends on the upper ($\\Lambda_u$) and the lower ($\\Lambda_l$) cut-off as ${\\bar \\Lambda} \\propto \\Lambda_u^{1-D/d} \\Lambda_l^{D/d}$. Current analysis of v...

  11. Measuring Baryon Acoustic Oscillations from the clustering of voids

    CERN Document Server

    Liang, Yu; Chuang, Chia-Hsun; Kitaura, Francisco-Shu; Tao, Charling

    2015-01-01

    We investigate the necessary methodology to optimally measure the baryon acoustic oscillation (BAO) signal, from voids based on galaxy redshift catalogues. To this end, we study the dependency of the BAO signal on the population of voids classified by their sizes. We find for the first time the characteristic features of the correlation function of voids including the first robust detection of BAOs in mock galaxy catalogues. These show an anti-correlation around the scale corresponding to the smallest size of voids in the sample (the void exclusion effect), and dips at both sides of the BAO peak, which can be used to determine the significance of the BAO signal without any priori model. Furthermore, our analysis demonstrates that there is a scale dependent bias for different populations of voids depending on the radius, with the peculiar property that the void population with the largest BAO significance corresponds to tracers with approximately zero bias on the largest scales. We further investigate the meth...

  12. Baryon effects on void statistics in the EAGLE simulation

    CERN Document Server

    Paillas, Enrique; Padilla, Nelson; Tissera, Patricia; Helly, John; Schaller, Matthieu

    2016-01-01

    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. We analyse voids in the mass and subhalo density field in the EAGLE simulations, which follow the evolution of galaxies in a Lambda cold dark matter Universe with state-of-the-art subgrid models for baryonic processes. We study the effect of baryons on void statistics by comparing results with simulations that only follow the evolution of DM, but use the same initial conditions as EAGLE. When using the mass in the simulation, we find that a DM-only simulation produces 24 per cent more voids than a hydrodynamical one, but this difference comes mainly from voids with radii smaller than 5 Mpc. We do not find significant differences in the density profiles between voids in EAGLE and its...

  13. An investigation of tendon sheathing filler migration into concrete

    Energy Technology Data Exchange (ETDEWEB)

    Naus, D.J.; Oland, C.B. [Oak Ridge National Lab., TN (United States)

    1998-03-01

    During some of the inspections at nuclear power plants with prestressed concrete containments, it was observed that the containments has experienced leakage of the tendon sheathing filler (i.e., streaks). The objective of this activity was to provide an indication of the extent of tendon sheathing filler leakage into the concrete and its affects on concrete properties. Literature was reviewed and concrete core samples were obtained from the Trojan Nuclear Plant and tested. The literature primarily addressed effects of crude or lubricating oils that are known to cause concrete damage. However, these materials have significantly different characteristics relative to the materials used as tendon sheathing fillers. Examination and testing of the concrete cores indicated that the appearance of tendon sheathing filler on the concrete surface was due to leakage from the conduits and its subsequent migration through cracks that were present. Migration of the tendon sheathing filler was confined to the cracks and there was no perceptible movement into the concrete. Results of compressive strength testing indicated that the concrete quality was consistent in the containment and that the strength had increased over 40% in 25.4 years relative to the average compressive strength at 28-days age.

  14. Complications caused by injection of dermal filler in Danish patients

    DEFF Research Database (Denmark)

    Uth, Charlotte Caspara; Elberg, Jens Jørgen; Zachariae, Claus

    2016-01-01

    Background: The usage of dermal fillers has increased significantly in recent years. Soft tissue augmentation with fillers helps to diminish the facial lines and to restore volume and fullness in the face at a relatively low cost. With the increasing number of treatments, the number of complicati......Background: The usage of dermal fillers has increased significantly in recent years. Soft tissue augmentation with fillers helps to diminish the facial lines and to restore volume and fullness in the face at a relatively low cost. With the increasing number of treatments, the number...... of complications is likely to increase as well.  Methods: A total of 37 patients with complications were collected retrospectively during a period of 13 years using original data files. Information on the type, date, number and location of the injections, type and date of complications, treatment, bacteria...... and complications was 2 years (range 1 day–8 years). The most common reported complications were edema (81 %), noduli (67.7 %), infections (54.1 %), discoloration (51.4 %), and granuloma formation (48.6 %). Surgical removal of the filler material was attempted in four patients.  Conclusions: With the increased use...

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

    DEFF Research Database (Denmark)

    McAllister, Iain Wilson

    1992-01-01

    After partial discharge activity within a gaseous void, charges accumulate on the wall of the void. The decay of such charges due to surface currents at the void wall is studied analytically, and the factors affecting this decay are indicated. The results show that in terms of the basic time...... 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...

  16. Influence of magnetic field-aided filler orientation on structure and transport properties of ferrite filled composites

    Science.gov (United States)

    Goc, K.; Gaska, K.; Klimczyk, K.; Wujek, A.; Prendota, W.; Jarosinski, L.; Rybak, A.; Kmita, G.; Kapusta, Cz.

    2016-12-01

    Epoxy resins are materials commonly used for insulations and encapsulations due to their easy processing process and mechanical strength. For their applications in power industry and electronics the effective heat dissipation is essential, thus their thermal conductivity is one of the most important properties. Introduction of appropriate dielectric powders, preferably in an ordered way, can increase the thermal conductivity of the polymer while keeping its good electrical insulation properties. In this work we used strontium ferrite as a filler to study the evolution of the filler particles distribution in the fluid before curing. Magnetic ferrite particles were dispersed in liquid epoxy resin and formation of chain-like or more complex structures under applied external magnetic field was observed and investigated. Computer simulations made show that with increasing magnetic field these structures are characterized by longer chains, higher speed of particles displacement and stronger structural anisotropy. However, for highly-filled systems, stronger inter-particle interactions make the alignment process less effective. The effective thermal conductivity simulated with FEM methods increases with increasing filler content and the percolation threshold in aligned systems is achieved at lower filler concentrations than for reference isotropic samples. The results are compared with the experimental data and a good qualitative agreement is obtained.

  17. Comparative evaluation of dental resin composites based on micron- and submicron-sized monomodal glass filler particles.

    Science.gov (United States)

    Valente, Lisia L; Peralta, Sonia L; Ogliari, Fabrício A; Cavalcante, Larissa M; Moraes, Rafael R

    2013-11-01

    A model resin composite containing a novel monomodal inorganic filler system based on submicron-sized Ba-Si-Al glass particles (NanoFine NF180; Schott) was formulated and compared with an experimental composite containing micron-sized particles (UltraFine UF1.0; Schott). The filler particles were characterized using X-ray microanalysis and granulometry, while the composites were characterized in terms of filler-resin morphology, radiopacity, degree of CC conversion, hardness, flexural strength/modulus, work-of-fracture, surface roughness and gloss (before and after simulated toothbrushing abrasion), and bulk compressive creep. The composites were formulated from the same photoactivated dimethacrylate co-monomer, incorporating mass fractions of 75% micron- and 78% submicron-sized particles. Quantitative data were analyzed at a significance level of pcomposites were similar in radiopacity, flexural strength, work-of-fracture, and creep. The submicron composite was harder but had lower flexural modulus and CC conversion. No significant differences in roughness were observed before brushing, although the submicron composite had higher gloss. Brushing increased roughness and decreased gloss on both materials, but the submicron composite retained higher gloss after brushing. The monomodal submicron glass filler system demonstrated potential for use in restorative dental composites, particularly due to improved esthetic properties. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  18. Carboxylated nitrile butadiene rubber/hybrid filler composites

    Directory of Open Access Journals (Sweden)

    Ahmad Mousa

    2012-08-01

    Full Text Available The surface properties of the OSW and NLS are measured with the dynamic contact-angle technique. The x-ray photoelectron spectroscopy (XPS of the OSW reveals that the OSW possesses various reactive functional groups namely hydroxyl groups (OH. Hybrid filler from NLS and OSW were incorporated into carboxylated nitrile rubber (XNBR to produce XNBR hybrid composites. The reaction of OH groups from the OSW with COOH of the XNBR is checked by attenuated total reflectance spectra (ATR-IR of the composites. The degree of curing ΔM (maximum torque-minimum torque as a function of hybrid filler as derived from moving die rheometer (MDR is reported. The stress-strain behavior of the hybrid composites as well as the dynamic mechanical thermal analysis (DMTA is studied. Bonding quality and dispersion of the hybrid filler with and in XNBR are examined using scanning-transmission electron microscopy (STEM in SEM.

  19. Comparative study of filler influence on polylactide photooxidation

    Directory of Open Access Journals (Sweden)

    S. Bocchini

    2013-05-01

    Full Text Available Polylactide (PLA based nanocomposites of organically modified montmorillonite and micro-talc based microcomposites were prepared with different compositions and were UV-light irradiated under artificial accelerated conditions representative of solar irradiation. The chemical modifications resulting from photo-oxidation were followed by infrared (IR and ultraviolet (UV-visible spectroscopies. The infrared analysis of PLA photooxidation shows the formation of a band at 1847 cm–1 due to the formation of anhydrides. The filler addition provokes an increase of anhydride formation rate dependent on filler nature, amount and dispersion degree on the matrix. The main factors that influence oxidation rate are the total extension of polymer/filler interfacial area and the presence of transition metal impurities of clays.

  20. 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.

  1. 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.

  2. Evolution of shock through a void in foam

    Science.gov (United States)

    Kim, Y.; Smidt, J. M.; Murphy, T. J.; Douglass, M. R.; Devolder, B. G.; Fincke, J. R.; Schmidt, D. W.; Cardenas, T.; Newman, S. G.; Hamilton, C. E.; Sedillo, T. J.; Los Alamos, NM 87544 Team

    2016-10-01

    Marble implosion is an experimental campaign intended to study the effects of heterogeneous mix on fusion burn. A spherical capsule is composed of deuterated plastic foam of controlled pore (or void) size with tritium fill in pores. As capsule implosion evolves, the initially separated deuterium and tritium will mix, producing DT yields. Void evolution during implosion is of interest for the Marble campaign. A shock tube, driven by the laser at Omega, was designed to study the evolution of a shock through a foam-filled ``void'' and subsequent void evolution. Targets were comprised of a 100 mg/cc CH foam tube containing a 200-µm diameter, lower density doped foam sphere. High-quality, radiographic images were obtained from both 2% iodine-doped in plastic foam and 15% tin-doped in aerogel foam. These experiments will be used to inform simulations.

  3. Measurement and Analysis of Sodium Void Reactivity Effect in CEFR

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The sodium void reactivity effect (SVRE) is one of the important parameters in the design and safety analysis of sodium-cooled fast reactors. In some serious accident conditions, for example the total instantaneous blockage (TIB) accident,

  4. Lower Face: Clinical Anatomy and Regional Approaches with Injectable Fillers.

    Science.gov (United States)

    Braz, André; Humphrey, Shannon; Weinkle, Susan; Yee, G Jackie; Remington, B Kent; Lorenc, Z Paul; Yoelin, Steve; Waldorf, Heidi A; Azizzadeh, Babak; Butterwick, Kimberly J; de Maio, Mauricio; Sadick, Neil; Trevidic, Patrick; Criollo-Lamilla, Gisella; Garcia, Philippe

    2015-11-01

    The use of injectable fillers enables facial sculpting through treatment of volume depletion and modeling of facial contours. Injectable fillers are among the most frequently performed minimally invasive cosmetic procedures.However, treatment of the lower third of the face can be challenging and requires expertise in facial anatomy. In this article, the authors provide a comprehensive review of the anatomy of the lower third of the face, highlighting danger zones. In addition, the authors describe their preferred approach and detailed technique used in the treatment of each specific area, namely the jawline, prejowl sulcus, melomental folds, and lips.

  5. 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)

  6. 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....

  7. Penggunaan precipitated calcium carbonate (PCC sebagai filler untuk sol karet sepatu olah raga

    Directory of Open Access Journals (Sweden)

    Herminiwati

    2010-12-01

    Full Text Available Abstract The objective of the research was to investigate the utilization of Precipitated Calcium Carbonate (PCC as filler in producing sport shoe rubber soles. PCC is a white filler needed for production of nonblack colour rubber products. There are four types of PCC that have been used including two local PCC from Wonosari and East Java, and two imported PCC from Japan and Taiwan. The amount of PCC added into the sport shoe sole rubber compound was varied in 30,45,60,75 and 90 per hundred rubber (phr. The compounding was carried-out by using two roll mills machine, and the compound was subsequently measured their optimum vulcanization time by using rheometer. The produced compound was then subjected to vulcanistion process by using hydrolic press at temperature 1500C and pressure 150 kg/ cm2. The quality of shoes sole vulcanisates were compare to standard quality of SNI. 12-7075-2005 about cemented system sport shoes. The results indicated that the best formula of rubber compound for sport shoes sole were made by using NR 80 phr, NBR 20 phr, paraffinic oil 10 phr, aluminium silicate 30 phr, ZnO 5 phr, TiO2 10 phr, stearic acid 1 phr, vulkanox SP 1 phr, paraffin wax 1 phr, TMTD 0,5 phr, CBS 2 phr, sulphur 1,2 phr with the amount of PCC Actifort 700 of 45 phr. The best formula meet the requirement SNI 12-7075-2005 and they were characterized by tensile sterength 16,79 N/mm2, elongation at break 529,92% tear resistance 9,06 N/mm2, specific gravity 1,28 g/cm3, hardness 55 shore A, Grasselli absrassion resistancing filler. The local PCC from Wonosari can be used for substitution of the imported PCC as the white filler for the production of rubber compound sport shoes sole. However, particle size reduction and coating or surface treatment of local PCC were needed for improving the quality and the role of reinforcing filler.

  8. Effect of biobased fillers nature on biodeterioration of hybrid polyethylene composites by mold fungi

    Science.gov (United States)

    Mastalygina, E. E.; Popov, A. A.; Pantyukhov, P. V.

    2017-06-01

    The paper is devoted to investigation of deterioration of natural fillers and polyethylene composites on their basis (polyethylene/filler=70/30) due to the action of mold fungi. The fillers chemical composition, dimensional parameters and biodegradability have been analyzed as factors exert a considerable impact on composite materials biodeterioration. It has been found that the principal factor determining the biodeterioration of polyethylene/filler composites by mold fungi is chemical composition of a filler and, in turn, its biodegradability. The excess of holocellulose content over lignin content and high protein content in a filler are able to induce biofouling of the polymeric composite materials. The presence of soluble and easy hydrolysed fraction in a filler increases its availability in a polymeric matrix. According to the study results, most effective natural fillers as additives stimulating polyethylene composites biodegradability are milled straw of seed flax and hydrolyzed keratin of bird’s feather.

  9. Effect of precipitated calcium carbonate--Cellulose nanofibrils composite filler on paper properties.

    Science.gov (United States)

    He, Ming; Cho, Byoung-Uk; Won, Jong Myoung

    2016-01-20

    A new concept of composite filler was developed by using cellulose nanofibrils (CNF), precipitated calcium carbonate (PCC) and cationic starch (C-starch). In this study, cellulose nanofibrils were utilized in two different ways: a PCC-CNF composite filler and a papermaking additive in sheet forming. The aim was to elucidate their effects on flocculation, filler retention and the strength and optical properties of handsheets. The highest filler retention was obtained by using the PCC-CNF composite filler in paper sheets. The paper filled with the composite fillers had much higher bursting and tensile strengths than conventional PCC loading. It was also found that the paper prepared with PCC-CNF composite fillers became denser with increasing the filler content of paper.

  10. Effect of filler addition on porosity and strength of polysiloxane-derived porous silicon carbide ceramics

    National Research Council Canada - National Science Library

    KUMAR, B. V. Manoj; EOM, Jung-Hye; KIM, Young-Wook

    2011-01-01

    Polycarbosilane (PCS) or silicon carbide (SiC) fillers were used as fillers in fabricating partially interconnected, open-cell porous SiC ceramics by carbothermal reduction of polysiloxane-derived SiOC and subsequent sintering process...

  11. Void Growth in Single and Bicrystalline Metals: Atomistic Calculations

    Science.gov (United States)

    Traiviratana, Sirirat; Bringa, Eduardo M.; Benson, David J.; Meyers, Marc A.

    2007-12-01

    MD simulations in monocrystalline and bicrystalline 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. However, 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 {111} planes, join at the intersection, the Burgers vector of the dislocations being parallel to the intersection of two {111} planes: a 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 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. Calculations were also carried out for a void at the interface between two grains.

  12. Low and High Surface Brightness Galaxies at Void Walls

    CERN Document Server

    Ceccarelli, L; Lambas, D G; Galaz, G; Padilla, N D

    2012-01-01

    We study the relative fraction of low and high surface brightness galaxies (LSBGs and HSBGs) at void walls in the SDSS DR7. We focus on galaxies in equal local density environments. We assume that the host dark-matter halo mass (for which we use SDSS group masses) is a good indicator of local density. This analysis allows to examine the behavior of the abundance of LSBG and HSBG galaxies at a fixed local density and distinguish the large-scale environment defined by the void geometry. We compare galaxies in the field, and in the void walls; the latter are defined as the volume of void shells of radius equal to that of the void. We find a significant decrement, a factor $\\sim 4$, of the relative fraction of blue, active star-forming LSBGs in equal mass groups at the void walls and the field. This decrement is consistent with an increase of the fraction of blue, active star-forming HSBGs. By contrast, red LSBGs and HSBGs show negligible changes. We argue that these results are consistent with a scenario where L...

  13. The Effect of Nearby Voids on Galaxy Number Counts

    CERN Document Server

    Bucklein, Brian K; Hintz, Eric G

    2016-01-01

    The size, shape and degree of emptiness of void interiors sheds light on the details of galaxy formation. A particularly interesting question is whether void interiors are completely empty or contain a dwarf population. However the nearby voids that are most conducive for dwarf searches have large angular diameters, on the order of a steradian, making it difficult to redshift-map a statistically significant portion of their volume to the magnitude limit of dwarf galaxies. As part of addressing this problem, we investigate here the usefulness of number counts in establishing the best locations to search inside nearby (d < 300 Mpc) galaxy voids, utilizing Wolf plots of log(n < m) vs. m as the basic diagnostic. To illustrate expected signatures, we consider the signature of three void profiles, "cut out", "built up", and "universal profile" carved into Monte-Carlo Schechter function models. We then investigate the signatures of voids in the Millennium Run dark matter simulation and the Sloan Digital Sky Su...

  14. 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.

  15. Dual-Component Gelatinous Peptide/Reactive Oligomer Formulations as Conduit Material and Luminal Filler for Peripheral Nerve Regeneration.

    Science.gov (United States)

    Kohn-Polster, Caroline; Bhatnagar, Divya; Woloszyn, Derek J; Richtmyer, Matthew; Starke, Annett; Springwald, Alexandra H; Franz, Sandra; Schulz-Siegmund, Michaela; Kaplan, Hilton M; Kohn, Joachim; Hacker, Michael C

    2017-05-21

    Toward the next generation of nerve guidance conduits (NGCs), novel biomaterials and functionalization concepts are required to address clinical demands in peripheral nerve regeneration (PNR). As a biological polymer with bioactive motifs, gelatinous peptides are promising building blocks. In combination with an anhydride-containing oligomer, a dual-component hydrogel system (cGEL) was established. First, hollow cGEL tubes were fabricated by a continuous dosing and templating process. Conduits were characterized concerning their mechanical strength, in vitro and in vivo degradation and biocompatibility. Second, cGEL was reformulated as injectable shear thinning filler for established NGCs, here tyrosine-derived polycarbonate-based braided conduits. Thereby, the formulation contained the small molecule LM11A-31. The biofunctionalized cGEL filler was assessed regarding building block integration, mechanical properties, in vitro cytotoxicity, and growth permissive effects on human adipose tissue-derived stem cells. A positive in vitro evaluation motivated further application of the filler material in a sciatic nerve defect. Compared to the empty conduit and pristine cGEL, the functionalization performed superior, though the autologous nerve graft remains the gold standard. In conclusion, LM11A-31 functionalized cGEL filler with extracellular matrix (ECM)-like characteristics and specific biochemical cues holds great potential to support PNR.

  16. Dual-Component Gelatinous Peptide/Reactive Oligomer Formulations as Conduit Material and Luminal Filler for Peripheral Nerve Regeneration

    Directory of Open Access Journals (Sweden)

    Caroline Kohn-Polster

    2017-05-01

    Full Text Available Toward the next generation of nerve guidance conduits (NGCs, novel biomaterials and functionalization concepts are required to address clinical demands in peripheral nerve regeneration (PNR. As a biological polymer with bioactive motifs, gelatinous peptides are promising building blocks. In combination with an anhydride-containing oligomer, a dual-component hydrogel system (cGEL was established. First, hollow cGEL tubes were fabricated by a continuous dosing and templating process. Conduits were characterized concerning their mechanical strength, in vitro and in vivo degradation and biocompatibility. Second, cGEL was reformulated as injectable shear thinning filler for established NGCs, here tyrosine-derived polycarbonate-based braided conduits. Thereby, the formulation contained the small molecule LM11A-31. The biofunctionalized cGEL filler was assessed regarding building block integration, mechanical properties, in vitro cytotoxicity, and growth permissive effects on human adipose tissue-derived stem cells. A positive in vitro evaluation motivated further application of the filler material in a sciatic nerve defect. Compared to the empty conduit and pristine cGEL, the functionalization performed superior, though the autologous nerve graft remains the gold standard. In conclusion, LM11A-31 functionalized cGEL filler with extracellular matrix (ECM-like characteristics and specific biochemical cues holds great potential to support PNR.

  17. Analysis of filler--fibre interaction in fly ash filled short fibre-epoxy composites using ultrasonic NDE

    Indian Academy of Sciences (India)

    S M Kulkarni; D Anuradha; C R L Murthy; Kishore

    2002-04-01

    Size and aspect ratio are believed to influence the rheology or the flow in the mixture and in turn the mechanical performance of the composites. Fillers and fibres when used in combination are expected to complement each other's performance resulting in better properties for the composite. They also reduce the extent of matrix polymer required in the system. Composites involving fillers and fibres individually and in combination are studied for the level defect population using NDE and the mechanical performance under compression correlated with such an analysis. It was found that inclusion filler-fibre combination besides yielding better physical properties like density also yielded improved mechanical properties like strength and modulus. These properties showed an improvement of about 30-40% as compared to the ones where a single reinforcement either ash or fibre was used. Further, they exhibited uniform distribution of defects whose population was least compared to the situation where only one component (either filler or fibre) as reinforcement was tried.

  18. Influence of magnetic field-aided filler orientation on structure and transport properties of ferrite filled composites

    Energy Technology Data Exchange (ETDEWEB)

    Goc, K., E-mail: Kamil.Goc@fis.agh.edu.pl [Department of Solid State Physics, AGH University of Science and Technology, 30 Mickiewicza Street, 30-059 Krakow (Poland); Gaska, K.; Klimczyk, K.; Wujek, A.; Prendota, W.; Jarosinski, L. [Department of Solid State Physics, AGH University of Science and Technology, 30 Mickiewicza Street, 30-059 Krakow (Poland); Rybak, A.; Kmita, G. [ABB Corporate Research Center, 13A Starowislna Street, 31-038 Krakow (Poland); Kapusta, Cz. [Department of Solid State Physics, AGH University of Science and Technology, 30 Mickiewicza Street, 30-059 Krakow (Poland)

    2016-12-01

    Epoxy resins are materials commonly used for insulations and encapsulations due to their easy processing process and mechanical strength. For their applications in power industry and electronics the effective heat dissipation is essential, thus their thermal conductivity is one of the most important properties. Introduction of appropriate dielectric powders, preferably in an ordered way, can increase the thermal conductivity of the polymer while keeping its good electrical insulation properties. In this work we used strontium ferrite as a filler to study the evolution of the filler particles distribution in the fluid before curing. Magnetic ferrite particles were dispersed in liquid epoxy resin and formation of chain-like or more complex structures under applied external magnetic field was observed and investigated. Computer simulations made show that with increasing magnetic field these structures are characterized by longer chains, higher speed of particles displacement and stronger structural anisotropy. However, for highly-filled systems, stronger inter-particle interactions make the alignment process less effective. The effective thermal conductivity simulated with FEM methods increases with increasing filler content and the percolation threshold in aligned systems is achieved at lower filler concentrations than for reference isotropic samples. The results are compared with the experimental data and a good qualitative agreement is obtained. - Highlights: • Influence of magnetic field on the particle chains in epoxy composites is analysed. • Strontium ferrite fillers with good thermal and low electrical conductivity. • Influence of interparticle interactions for agglomeration efficiency. • The impact of chains formed on the heat transfer by creating conductive paths. • Connection between structural anisotropy and transport properties anisotropy.

  19. Isolation and control of voids and void-hillocks during molecular beam epitaxial growth of HgCdTe

    Science.gov (United States)

    Chandra, D.; Aqariden, F.; Frazier, J.; Gutzler, S.; Orent, T.; Shih, H. D.

    2000-06-01

    Formation of small voids and defect complexes involving small voids during the molecular beam epitaxial growth of mercury cadmium telluride on cadmium zinc telluride was investigated. Some of these defects were demonstrated to form away from the substrate-epi interface. Other defects were demonstrated to close before reaching the top surface without leaving any perturbations on the surface, thus remaining completely hidden. The voids, which formed away from the substrate-epifilm fixed interface, nucleated on defects introduced into the film already grown, leading to the formation of defect complexes, unlike the voids which nucleated at the substrate-epifilm fixed interface. These defect complexes are decorated with high density dislocation nests. The voids which closed before reaching the film surface usually also nucleated slightly away from the film-substrate interface, continued to replicate for a while as the growth progressed, but then relatively rapidly closed off at a significant depth from the film surface. These voids also appeared to form defect complexes with other kinds of defects. Correlations between these materials defects and performance of individual vertically integrated photodiode (VIP) devices were demonstrated, where the relative location of these defects with respect to the junction boundary appears to be particularly important. Elimination or reduction of fluctuations in relative flux magnitudes or substrate temperature, more likely during multi-composition layer growth, yielded films with significantly lower defect concentrations.

  20. Gamma-ray attenuation technique for measuring void fraction in horizontal gas-liquid two-phase flow

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The measurement of void fraction is of importance to the oil industry and chemical industry. In this article,the principle and mathematical method of determining the void fraction of horizontal gas-liquid flow by using a single-energy γ-ray system is described. The γ-ray source is the radioactive isotope of 241Am with γ-ray energy of 59.5 keV. The time-averaged value of the void fraction in a 50.0-mm i.d. transparent horizontal pipeline is measured under various combinations of the liquid flow and gas flow. It is found that increasing the gas flow rate at a fixed liquid flow rate would increase the void fraction. Test data are compared with the predictions of the correlations and a good agreement is found. The result shows that the designed γ-ray system can be used for measuring the void fraction in a horizontal gas-liquid two-phase flow with high accuracy.

  1. Impact of fillers on dissolution kinetic of fenofibrate dry foams.

    Science.gov (United States)

    Lenz, Elisabeth; Sprunk, Angela; Kleinebudde, Peter; Page, Susanne

    2015-01-01

    Dry foam technology reveals the opportunity to improve the dissolution behavior of poorly soluble drugs tending to agglomeration due to micronization. In this study, the impact of fillers on the manufacturability, the properties of dry foams and granules as well as the dissolution kinetics of dry foam tablets was investigated using fenofibrate as a model compound. Different maltodextrins and dried glucose syrups, a maltodextrin-phosphatidylcholine complex, isomalt and a 1:1 mixture of mannitol/glucose syrup were used as filler. Within the group of maltodextrins and glucose syrups, the influences of dextrose equivalent (DE), particle morphology and botanical source of starch were investigated. Comparable macroscopic foam structures were obtained with maltodextrins and glucose syrups whereas different foam morphologies were obtained for the other fillers tested. Regarding the maltodextrins and glucose syrups, different physicochemical and particle properties had a minor impact on granule characteristics and tablet dissolution. Using the maltodextrin-phosphatidylcholine complex resulted in a low specific surface area of the granules and a slow tablet dissolution caused by a slow disintegration. In contrast, a high specific surface area and a fast release were obtained with isomalt and glucose syrup/mannitol mixture indicating that high soluble low molecular weight fillers enable the development of fast dissolving dry foam tablets.

  2. Induction heating of mastic containing conductive fibers and fillers

    NARCIS (Netherlands)

    García, Á.; Schlangen, E.; Ven, M. van de; Vliet, D. van

    2011-01-01

    The objective of this research is to examine the induction heating of mastic through the addition of electrically conductive fillers and fibers (graphite and steel wool), and to prove that this material can be healed with induction energy. The effect of fibers content, sand-bitumen ratio and the com

  3. Induction heating of mastic containing conductive fibers and fillers

    NARCIS (Netherlands)

    García, Á.; Schlangen, E.; Van de Ven, M.; Van Vliet, D.

    The objective of this research is to examine the induction heating of mastic through the addition of electrically conductive fillers and fibers (graphite and steel wool), and to prove that this material can be healed with induction energy. The effect of fibers content, sand–bitumen ratio and the com

  4. Multipass Narrow Gap of Heavy Gauge Steel with Filler Wire

    Science.gov (United States)

    Markushov, Y.; Evtihiev, N.; Grezev, N.; Murzakov, M.

    This article describes method of heavy gauge welding using laser radiation as beam source of energy. The article contains the results of single-pass laser-arc welding and multipass laser welding with filler wire; highlight benefits and drawbacks of each welding method. The results obtained were compared with the traditional methods of welding of the same thickness.

  5. Effect of waste rubber powder as filler for plywood application

    Directory of Open Access Journals (Sweden)

    Ong Huei Ruey

    2015-03-01

    Full Text Available The study investigated the suitability of waste rubber powder (WRP use as filler in adhesive formulation for plywood application. Melamine Urea Formaldehyde (MUF was employed as resin for formulating the wood adhesive. To improve chemical properties and bonding quality of adhesive, WRP was treated by different chemicals like 20% nitric acid, 30% hydrogen peroxide and acetone solution. The treated WRP were analysed by XRD and it showed that inorganic compounds were removed and carbon was remained as major component under the treatment of 20% HNO3. The treatment improved the mechanical properties like shear strength and formaldehyde emission of plywood (high shear strength and low formaldehyde emission. The physico-chemical interaction between the wood, resin and filler was investigated using fourier transform infrared spectroscopic (FTIR technique and the interactions among N-H of MUF and C=O of wood and WRP were identified. The morphology of wood-adhesive interface was studied by field emission scanning electron microscope (FESEM and light microscope (LM. It showed that the penetration of adhesives and fillers through the wood pores was responsible for mechanical interlocking. Therefore, chemically treated WRP proved its potential use as filler in MUF based adhesive for making plywood.

  6. Fibrous Fillers to Manufacture Ultra High Ash/Performance Paper

    Energy Technology Data Exchange (ETDEWEB)

    Dr. VIjay K. Mathur

    2009-04-30

    The paper industry is one of the largest users of energy and emitters of CO2 in the US manufacturing industry. In addition to that, it is facing tremendous financial pressure due to lower cost imports. The fine paper industry has shrunk from 15 million tons per year production to 10 million tons per year in the last 5 years. This has resulted in mill closures and job loses. The AF&PA and the DOE formed a program called Agenda 2020 to help in funding to develop breakthrough technologies to provide help in meeting these challenges. The objectives of this project were to optimize and scale-up Fibrous Fillers technology, ready for commercial deployment and to develop ultra high ash/high performance paper using Fibrous Fillers. The goal was to reduce energy consumption, carbon footprint, and cost of manufacturing paper and related industries. GRI International (GRI) has been able to demonstrate the techno - economic feasibility and economic advantages of using its various products in both handsheets as well as in commercial paper mills. GRI has also been able to develop sophisticated models that demonstrate the effect of combinations of GRI's fillers at multiple filler levels. GRI has also been able to develop, optimize, and successfully scale-up new products for use in commercial paper mills.

  7. Breaking the vicious circle: Onabotulinum toxin A in children with therapy-refractory dysfunctional voiding

    NARCIS (Netherlands)

    L.A. 't Hoen (Lisette); J. van den Hoek (Joop); K.P. Wolffenbuttel (Katja); F. van der Toorn; J.R. Scheepe (Jeroen)

    2015-01-01

    textabstractIntroduction An increased activity of the external urethral sphincter or pelvic floor muscles during voluntary voiding leads to dysfunctional voiding. Frequently reported symptoms are urinary incontinence, urinary tract infections and high post-void residuals. Dysfunctional voiding is a

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

    DEFF Research Database (Denmark)

    Tvergaard, Viggo; Niordson, Christian Frithiof

    2008-01-01

    of the characteristic material length relative to the initial void radius. For a case showing the multiple void mechanism, it is found that the effect of the material length can change the behaviour towards the void by void mechanism. A material model with three characteristic length scales is compared with a one...

  9. A study of process induced voids in resistance welding of thermoplastic composites

    NARCIS (Netherlands)

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

    2015-01-01

    Void formation in resistance welding of woven fabric reinforced thermoplastic composites was investigated. Void contents were measured using optical microscopy and digital image process. Un-even void distributions were observed in the joints, and more voids were found in the middle of the joints tha

  10. Neutron Tomography Using Mobile Neutron Generators for Assessment of Void Distributions in Thermal Hydraulic Test Loops

    OpenAIRE

    Andersson, Peter; Bjelkenstedt, Tom; Andersson Sundén, Erik; Sjöstrand, Henrik; Jacobsson, Staffan

    2015-01-01

    Detailed knowledge of the lateral distribution of steam (void) and water in a nuclear fuel assembly is of great value for nuclear reactor operators and fuel manufacturers, with consequences for both reactor safety and economy of operation. Therefore, nuclear relevant two-phase flows are being studied at dedicated thermal-hydraulic test loop, using twophase flow systems ranging from simplified geometries such as heated circular pipes to full scale mock-ups of nuclear fuel assemblies. Neutron t...

  11. 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.

  12. Irradiation creep relaxation of void swelling-driven stresses

    Energy Technology Data Exchange (ETDEWEB)

    Hall, M.M., E-mail: hallmm63@comcast.net [MacRay Consulting, 1366 Hillsdale Drive, Monroeville, PA (United States)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer Irradiation void swelling can cause distortion of reactor core components. Black-Right-Pointing-Pointer Constrained swelling can drive stresses beyond acceptable levels. Black-Right-Pointing-Pointer Compressive stresses decrease irradiation swelling rates. Black-Right-Pointing-Pointer Irradiation creep relaxes swelling-driven stresses and core restraint forces. Black-Right-Pointing-Pointer Swelling-driven creep stresses are consistent with predictions of a proposed model. - Abstract: Swelling-driven-creep test specimens are used to measure the compressive stresses that develop due to constraint of irradiation void swelling. These specimens use a previously non-irradiated 20% CW Type 316 stainless steel holder to axially restrain two Type 304 stainless steel tubular specimens that were previously irradiated in the US Experimental Breeder Reactor (EBR-II) at 490 Degree-Sign C. One specimen was previously irradiated to fluence levels in the void nucleation regime (9 dpa) and the other in the quasi-steady void growth regime (28 dpa). A lift-off compliance measurement technique was used post-irradiation to determine compressive stresses developed during reirradiation of the two specimen assemblies in Row 7 of EBR-II at temperatures of 547 Degree-Sign C and 504 Degree-Sign C, respectively, to additional damage levels each of about 5 dpa. Results obtained on the higher fluence swelling-driven-creep specimen show that compressive stress due to constraint of swelling retards void swelling to a degree that is consistent with active load uniaxial compression specimens that were irradiated as part of a previously reported multiaxial in-reactor creep experiment. Swelling results obtained on the lower fluence swelling-driven creep specimen show a much larger effect of compressive stress in reducing swelling, demonstrating that the larger effect of stress on swelling is on void nucleation as compared to void growth. Test results are

  13. Polymer surface modification and characterization of particulate calcium carbonate fillers

    Energy Technology Data Exchange (ETDEWEB)

    Shui Miao

    2003-12-30

    The efficacy of the surface treatment of particulate fillers depends on the chemical character of the components, on the method and conditions of the treatment, and on the amount of the treating agent. Here, the ultra-fine calcium carbonate is surface treated with 1, 2, 3 and 4 wt.% polyacrylic acid (PAA) synthesized by ourselves, which has strong ionic interaction and is an efficient surface modifier. The PAA coated filler is submitted to the measurement of the surface bonded amount, bonding efficacy, X-ray photoelectron spectroscopy (XPS) and inverse gas chromatography. Maximum efficacy is expected at the monolayer coverage of the surface, which is about 0.6 wt.% according to the calculation based on the way they are aligned and is basically in agreement with the 'substrate overlayer' model based on the mole ratio of C{sup 286} and C{sup 290} taking no account of the possible underestimation because of the inaccuracy or because of the CH{sub x} contamination present originally on the CaCO{sub 3}. The initial decrease of the mole ratio of C{sup 290}/O and C{sup 290}/Ca with the surface bonded PAA may indicate that the bonding interaction between the polymer and the filler surface is the leaving of one molecular carbon dioxide. The IGC measurement shows that there is a considerable surface tension falling in the case of the PAA modified filler compared with the reference. An abnormal high surface energy in the case of filler treated with 4% PAA is observed.

  14. 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.

  15. HDPE-HA composites synthetized by in situ polymerization with different filler content

    Science.gov (United States)

    Hermán, V.; Karam, A.; Albano, C.; Romero, K.; González, G.

    2012-07-01

    In Situ ethylene polymerization was used to synthesize high density polyethylene - hydroxyapatite (HDPE-HA) composites, employing Cp2ZrCl2/MAO as catalytic system. A good dispersion of HA into the HDPE matrix was obtained when the following synthesis conditions were combined: high stirring velocities (2000 rpm), low quantities of solvent (100 mL), and 10 °C. Under these conditions different filler content was used to synthetized HDPE-HA composites. An interaction between HA and HDPE was obtained by FTIR. On the other hand, thermal analysis indicated that no significant differences were observed between HDPE and the composites.

  16. Neural network modeling for dynamic pulsed GTAW process with wire filler based on MATLAB

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Double-sided weld pool shapes were determined by multiple welding parameters and wire feed parameters during pulsed GTAW with wire filler. Aiming at such a system with multiple inputs and outputs, an effective modeling method, consisting of the impulse signal design, model structure and parameter identification and verification, was developed based on MATLAB software. Then, dynamic neural network models, TDNNM (Topside dynamic neural network model) and BHDNNM (Backside width and topside height dynamic neural network model), were established to predict double-sided shape parameters of the weld pool. The characteristic relationship of the welding process was simulated and analyzed with the models.

  17. Characterisation and measurement of signals generated by DVB-H 'GAP-filler' repeaters.

    Science.gov (United States)

    Baldini, M; Barellini, A; Bogi, L; Licitra, G; Silvi, A M; Zari, A

    2009-12-01

    DVB-H (Digital Video Broadcasting Handheld) is the standard developed by DVB Project and approved by ETSI with the aim of providing the reception of DVB signals even in mobility but also data transfers and multimedia services. The introduction and development of the DVB-H system is still ongoing. In this context, this work focuses on the temporal trend of electromagnetic impact of an urban DVB-H repeater (called 'gap-filler') for exposure assessment purposes; it also describes a method for its measurement by means of narrow band instrumental chains.

  18. An international perspective on fillers in dermatology-from an American perspective.

    Science.gov (United States)

    Gold, Michael H

    2012-09-01

    This manuscript is intended to give one an international perspective on the use of fillers around the world-what makes some of them special and what is the need and what is the purpose of having so many fillers in this global dermatologic community we live in. In the US, we have a finite number of fillers and only a handful more currently going through FDA testing. We demand much from our fillers in terms of safety and efficacy, and for all of us in the US, this is a very good reason to keep the numbers of fillers available to a reasonable number.

  19. Autonomous robot for detecting subsurface voids and tunnels using microgravity

    Science.gov (United States)

    Wilson, Stacy S.; Crawford, Nicholas C.; Croft, Leigh Ann; Howard, Michael; Miller, Stephen; Rippy, Thomas

    2006-05-01

    Tunnels have been used to evade security of defensive positions both during times of war and peace for hundreds of years. Tunnels are presently being built under the Mexican Border by drug smugglers and possibly terrorists. Several have been discovered at the border crossing at Nogales near Tucson, Arizona, along with others at other border towns. During this war on terror, tunnels under the Mexican Border pose a significant threat for the security of the United States. It is also possible that terrorists will attempt to tunnel under strategic buildings and possibly discharge explosives. The Center for Cave and Karst Study (CCKS) at Western Kentucky University has a long and successful history of determining the location of caves and subsurface voids using microgravity technology. Currently, the CCKS is developing a remotely controlled robot which will be used to locate voids underground. The robot will be a remotely controlled vehicle that will use microgravity and GPS to accurately detect and measure voids below the surface. It is hoped that this robot will also be used in military applications to locate other types of voids underground such as tunnels and bunkers. It is anticipated that the robot will be able to function up to a mile from the operator. This paper will describe the construction of the robot and the use of microgravity technology to locate subsurface voids with the robot.

  20. The Aspen--Amsterdam Void Finder Comparison Project

    CERN Document Server

    Colberg, Joerg M; Foster, Caroline; Platen, Erwin; Brunino, Riccardo; Neyrinck, Mark; Basilakos, Spyros; Fairall, Anthony; Feldman, Hume; Gottloeber, Stefan; Hahn, Oliver; Hoyle, Fiona; Mueller, Volker; Nelson, Lorne; Plionis, Manolis; Porciaini, Cristiano; Shandarin, Sergei; Vogeley, Michael S; van de Weygaert, Rien

    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 results without worrying about whether such a comparison in fact makes sense. Because of the recent increased interest in voids, both in very large galaxy surveys and in detailed simulations of cosmic structure formation, this situation is very unfortunate. We here present the first systematic comparison study of thirteen different void finders constructed using particles, haloes, and semi--analytical model galaxies extracted from a subvolume of the Millennium simulation. The study includes many groups that have studied voids over the past decade. We show their results and discuss their differences and agreements. As it turns out, the basic results of the various methods agree very well with each other in that they...

  1. An analytical model for porous single crystals with ellipsoidal voids

    Science.gov (United States)

    Mbiakop, A.; Constantinescu, A.; Danas, K.

    2015-11-01

    A rate-(in)dependent constitutive model for porous single crystals with arbitrary crystal anisotropy (e.g., FCC, BCC, HCP, etc.) containing general ellipsoidal voids is developed. The proposed model, denoted as modified variational model (MVAR), is based on the nonlinear variational homogenization method, which makes use of a linear comparison porous material to estimate the response of the nonlinear porous single crystal. Periodic multi-void finite element simulations are used in order to validate the MVAR for a large number of parameters including cubic (FCC, BCC) and hexagonal (HCP) crystal anisotropy, various creep exponents (i.e., nonlinearity), several stress triaxiality ratios, general void shapes and orientations and various porosity levels. The MVAR model, which involves a priori no calibration parameters, is found to be in good agreement with the finite element results for all cases considered in the rate-dependent context. The model is then used in a predictive manner to investigate the complex response of porous single crystals in several cases with strong coupling between the anisotropy of the crystal and the (morphological) anisotropy induced by the shape and orientation of the voids. Finally, a simple way of calibrating the MVAR with just two adjustable parameters is depicted in the rate-independent context so that an excellent agreement with the FE simulation results is obtained. In this last case, this proposed model can be thought as a generalization of the Gurson model in the context of porous single crystals and general ellipsoidal void shapes and orientations.

  2. 3D Property Modeling of Void Ratio by Cokriging

    Institute of Scientific and Technical Information of China (English)

    Yao Lingqing; Pan Mao; Cheng Qiuming

    2008-01-01

    Void ratio measures compactness of ground soil in geotechnical engineering. When samples are collected in certain area for mapping void ratios, other relevant types of properties such as water content may be also analyzed. To map the spatial distribution of void ratio in the area based on these types of point, observation data interpolation is often needed. Owing to the variance of sampling density along the horizontal and vertical directions, special consideration is required to handle anisotropy of estimator. 3D property modeling aims at predicting the overall distribution of property values from limited samples, and geostatistical method can he employed naturally here because they help to minimize the mean square error of estimation. To construct 3D property model of void ratio, cokriging was used considering its mutual correlation with water content, which is another important soil parameter. Moreover, K-D tree was adopted to organize the samples to accelerate neighbor query in 3D space during the above modeling process. At last, spatial configuration of void ratio distribution in an engineering body was modeled through 3D visualization, which provides important information for civil engineering purpose.

  3. Only the Lonely: H I Imaging of Void Galaxies

    CERN Document Server

    Kreckel, K; Aragón-Calvo, M A; van Gorkom, J H; van de Weygaert, R; van der Hulst, J M; Kovač, K; Yip, C -W; Peebles, P J E

    2010-01-01

    Void galaxies, residing within the deepest underdensities of the Cosmic Web, present an ideal population for the study of galaxy formation and evolution in an environment undisturbed by the complex processes modifying galaxies in clusters and groups, as well as provide an observational test for theories of cosmological structure formation. We have completed a pilot survey for the HI imaging aspects of a new Void Galaxy Survey (VGS), imaging 15 void galaxies in HI in local (d < 100 Mpc) voids. HI masses range from 3.5 x 10^8 to 3.8 x 10^9 M_sun, with one nondetection with an upper limit of 2.1 x 10^8 M_sun. Our galaxies were selected using a structural and geometric technique to produce a sample that is purely environmentally selected and uniformly represents the void galaxy population. In addition, we use a powerful new backend of the Westerbork Synthesis Radio Telescope that allows us to probe a large volume around each targeted galaxy, simultaneously providing an environmentally constrained sample of for...

  4. 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...

  5. 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

    2016-08-01

    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 Ωm=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 ¯=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, ɛ =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.

  6. Magnetic pattern at supergranulation scale: the Void Size Distribution

    CERN Document Server

    Berrilli, Francesco; Del Moro, Dario

    2014-01-01

    The large-scale magnetic pattern of the quiet sun is dominated by the magnetic network. This network, created by photospheric magnetic fields swept into convective downflows, delineates the boundaries of large scale cells of overturning plasma and exhibits voids in magnetic organization. Such voids include internetwork fields, a mixed-polarity sparse field that populate the inner part of network cells. To single out voids and to quantify their intrinsic pattern a fast circle packing based algorithm is applied to 511 SOHO/MDI high resolution magnetograms acquired during the outstanding solar activity minimum between 23 and 24 cycles. The computed Void Distribution Function shows a quasi-exponential decay behavior in the range 10-60 Mm. The lack of distinct flow scales in such a range corroborates the hypothesis of multi-scale motion flows at the solar surface. In addition to the quasi-exponential decay we have found that the voids reveal departure from a simple exponential decay around 35 Mm.

  7. Study of galaxies in the Lynx-Cancer void. VI. HI-observations with the Nancay Radio Telescope

    CERN Document Server

    Pustilnik, S A

    2016-01-01

    Context. Void population consists mainly of late-type and low surface brightness (LSB) dwarf galaxies whose atomic hydrogen is the main component of their baryonic matter. Therefore, observations of void galaxy HI are mandatory in order to understand their evolution and dynamics. Aims. Our aim was to obtain integrated HI parameters for a fainter part of the nearby Lynx-Cancer void galaxy sample (total of 45 objects) with the Nancay Radio Telescope (NRT) and to conduct the comparative analysis of all the 103 void galaxies with known HI data with a sample of similar galaxies residing in denser environments of the Local Volume. Methods. For HI observations we used the NRT with its sensitive antenna/receiver system FORT and standard processing. The comparison of the void and control samples on the parameter M(HI)/L_B is conducted with the non-parametric method `The 2x2 Contingency Table test'. Results. We obtained new HI data for about 40% of the Lynx-Cancer galaxy sample. Along with data from the literature, we ...

  8. Optical coherence tomography for image-guided dermal filler injection and biomechanical evaluation

    Science.gov (United States)

    Singh, Manmohan; Wang, Shang; Yee, Richard W.; Han, Zhaolong; Aglyamov, Salavat R.; Larin, Kirill V.

    2017-02-01

    Dermal fillers are a very popular anti-ag ing treatment with estimated sales in the billions of dollars and millions of procedures performed. As the aging population continues to grow, these figures are only e xpected to increase. Dermal fillers have various compositions depending on their intended applicati on. Reactions to dermal fillers can be severe, such as ischemic events and filler migration to the eyes. Howe ver, these adverse reactions are rare. Nevertheless, the capability to perform imag e-guided filler injections would minimize th e risk of such reacti ons. In addition, the biomechanical properties of various fillers have been evalua ted, but there has been no investigation on the effects of filler on the biomechanical properties of skin. In this work, we utilize optical cohe rence tomography (OCT) for visualizing dermal filler injections with micrometer-scale sp atial resolution. In addition, we utilize noncontact optical coherence elastography (OCE) to quantify the changes in the biomechan ical properties of pig skin after the dermal filler injections. OCT was successfully able to visualize the dermal filler injecti on process, and OCE showed that the viscoelasticity of the pig skin was increased locally at the filler injection sites. OCT may be able to provide real-time image guidance in 3D, and when combined with functional OCT techniques such as optical microangiography, could be used to avoid blood vessels during the injection.

  9. Pengaruh Penggunaan Aspal Buton sebagai Filler Campuran Split Mastic Asphalt terhadap Karakteristik Marshall

    Directory of Open Access Journals (Sweden)

    Nuryadin Eko Raharjo

    2008-05-01

    Full Text Available Penelitian ini bertujuan untuk menguji penggunaan asbuton sebagai filler dalam campuran SMA beserta pengaruhnya terhadap karakteristik marshal yang meliputi: VITM, VFWA, Stabilitas, flow dan MQ. Penelitian ini menggunakan metode eksperimen dengan menguji penggunaan asbuton sebagai filler dalam campuran SMA. Variasi kadar asbuton sebagai filler dibuat 4%, 4,5%, 5%, 5,5% dan 6%. Setiap varian dalam penelitian ini menggunakan 3 benda uji sehingga jumlah sampel adalah 15 buah. Uji menggunakan Aspal yang digunakan Aspalt AC 80/100. Filler yang digunakan Asbuton mikro B30. Kadar aspal yang digunakan ditetapkan sebesar  7%. Analisis data dilakukan dengan menggunakan statistik deskriptif Penelitian ini menyimpulkan bahwa: (1 nilai VITM akan mengalami penurunan seiring bertambahnya kadar filler asbuton mikro, (2 penambahan filler asbuton kadar 4 – 5% akan meningkatkan nilai VFWA , namun pada kadar filler 5,5% dan 6% akan menurunkan nilai VFWA karena filler yang digunakan terlalu banyak sehingga persentase bitumen terhadap total aspal dalam campuran juga semakin besar, (3 penggunaan asbuton mikro filler pada campuran SMA memberi pengaruh menurunnya nilai stabilitas (4 penambahan filler asbuton mikro akan menaikkan nilai flow, hal ini terjadi karena dengan penambahan asbuton mikro kandungan aspal pada campuran akan bertambah, dan (5 nilai MQ mengalami penurunan seiring dengan bertambahnya kadar filler.

  10. Study on a novel Sn-electroplated silver brazing filler metal

    Science.gov (United States)

    Wang, Xingxing; Peng, Jin; Cui, Datian

    2017-08-01

    Novel Sn-electroplated Ag brazing filler metal with a high tin content was prepared by combining the plating and thermal diffusion method. The BAg45CuZn alloy was used as a base filler metal, and a Sn layer was electroplated on it. Then the H62 brass was brazed with the Sn-plated brazing filler metal containing 6.2 wt% of Sn. The results showed that the microstructure of the brazed joints with the Sn-plated filler mainly consisted of the Ag phase, Cu phase, CuZn phase and Cu5Zn8 phase. The tensile strength of the joints brazed with the Sn-plated filler metal was 326 MPa, which was higher than that of the joints with the base filler metal. Fracture analysis showed that the fractures of the joints brazed by the Sn-plated filler metal was mainly ductile fracture mixed with a small quantity of brittle fracture.

  11. Thermal analysis of resin composites with ellipsoidal filler considering thermal boundary resistance

    Science.gov (United States)

    Asakuma, Yusuke; Yamamoto, Tsuyoshi

    2016-10-01

    The effective thermal conductivity of composites with ellipsoidal fillers is analyzed by using a homogenization method that is able to represent the microstructure precisely. In this study, various parameters such as the volume fraction, shape, and distribution of the filler are quantitatively estimated to understand the mechanisms of heat transfer in the composite. First, thermal boundary resistance between resin and filler is important for obtaining composites with higher thermal conductivity. Second, the anisotropy of the effective thermal conductivity arises from contact between filler in the case of ellipsoidal filler and produces lower thermal resistance. Finally, the filler network and thermal resistance are essential for the heat transfer in composites because the path of thermal conduction is improved by contact between neighboring filler particles.

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

    CERN Document Server

    Hoeft, Matthias

    2010-01-01

    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 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 ultra-violet background radiation low-mass haloes show generally are 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 km/s. The suppressed baryon accretion is caused by the...

  13. On the void explanations of the Cold Spot

    CERN Document Server

    Marcos-Caballero, A; Martínez-González, E; Vielva, P

    2015-01-01

    The integrated Sachs-Wolfe (ISW) contribution induced on the cosmic microwave background by the presence of a supervoid as the one detected by Szapudi et al. (2015) is reviewed in this letter in order to check whether it could explain the Cold Spot (CS) anomaly. Two different models, previously used for the same purpose, are considered to describe the matter density profile of the void: a top hat function and a compensated profile produced by a Gaussian potential. The analysis shows that, even enabling ellipticity changes or different values for the dark-energy equation of state parameter $\\omega$, the ISW contribution due to the presence of the void does not reproduce the properties of the CS. Finally, the probability of alignment between the void and the CS is also questioned as an argument in favor of a physical connection between these two phenomena.

  14. Study of void sizes and loading configurations effects on shock initiation due to void collapse in heterogeneous energetic materials

    Science.gov (United States)

    Roy, Sidhartha; Rai, Nirmal; Udaykumar, H. S.

    2015-06-01

    In heterogeneous energetic materials, presence of porosity has been seen to increase its sensitivity towards shock initiation and ignition. Under the application of shock load, the viscoplastic deformation of voids and its collapse leads to the formation of local high temperature regions known as hot spots. The chemical reaction triggers at the hot spot depending on the local temperature and grows eventually leading to ignition and formation of detonation waves in the material. The temperature of the hot spot depends on various factors such as shock strength, void size, void arrangements, loading configuration etc. Hence, to gain deeper understanding on shock initiation and ignition study due to void collapse, a parametric study involving various factors which can affect the hot spot temperature is desired. In the current work, effects of void sizes, shock strength and loading configurations has been studied for shock initiation in HMX using massively parallel Eulerian code, SCIMITAR3D. The chemical reaction and decomposition for HMX has been modeled using Henson-Smilowitz multi step mechanism. The effect of heat conduction has also been taken into consideration. Ignition threshold criterion has been established for various factors as mentioned. The critical hot spot temperature and its size which can lead to ignition has been obtained from numerical experiments.

  15. Voiding trial outcome following pelvic floor repair without incontinence procedures

    Science.gov (United States)

    Wang, Rui; Won, Sara; Haviland, Miriam J.; Bargen, Emily Von; Hacker, Michele R.; Li, Janet

    2016-01-01

    Introduction and hypothesis Our aim was to identify predictors of postoperative voiding trial failure among patients who had a pelvic floor repair without a concurrent incontinence procedure in order to identify low-risk patients in whom postoperative voiding trials may be modified. Methods We conducted a retrospective cohort study of women who underwent pelvic floor repair without concurrent incontinence procedures at two institutions from 1 November 2011 through 13 October 2013 after abstracting demographic and clinical data from medical records. The primary outcome was postoperative retrograde voiding trial failure. We used modified Poisson regression to calculate the risk ratio (RR) and 95 % confidence interval (CI). Results Of the 371 women who met eligibility criteria, 294 (79.2 %) had complete data on the variables of interest. Forty nine (16.7%) failed the trial, and those women were less likely to be white (p = 0.04), more likely to have had an anterior colporrhaphy (p = 0.001), and more likely to have had a preoperative postvoid residual (PVR) ≥150 ml (p = 0.001). After adjusting for race, women were more likely to fail their voiding trial if they had a preoperative PVR of ≥150 ml (RR: 1.9; 95 % CI: 1.1–3.2); institution also was associated with voiding trial failure (RR: 3.0; 95 % CI: 1.6–5.4). Conclusions Among our cohort, postoperative voiding trial failure was associated with a PVR of ≥150 ml and institution at which the surgery was performed. PMID:26886553

  16. Experimental and numerical investigation of voids distribution in VPI for ITER correction coil

    Energy Technology Data Exchange (ETDEWEB)

    Li, Juping, E-mail: ljping@ipp.ac.cn; Wu, Jiefeng; Yu, Xiaowu

    2015-06-15

    Highlights: • A sample of correction coil was treated by vacuum pressure impregnation. • The voids in sample were observed by computed tomography. • The voids distributions were simulated in 2-D and 3-D model. • The calculated voids locations had a good agreement with experiment. • The simulation was not accurate in calculating the voids content. - Abstract: The experimental and numerical investigations were conducted to study the voids distribution in VPI (Vacuum Pressure Impregnation) process for correction coil. A sample of correction coil was manufactured by VPI. The voids in sample were observed with computed tomography and the average voids content was tested. The voids content is closely related to infiltration velocity and fluid properties. In former researches, the parameters affecting voids content were combined into a single parameter, namely capillary number. By calculating the capillary numbers in different areas of the sample, the voids distribution could be acquired. The corresponding numerical analyses based on Darcy law were conducted in 2-D and 3-D models. The 2-D case was used to simulate the voids distribution on the section as a simplified model, while the 3-D case demonstrated the spatial distribution of voids. The voids locations were similar in 2-D and 3-D cases, but the voids contents were different. The numerical results were compared with the actual voids distribution in sample. It was found the voids locations were close in numerical and experimental results, but the voids content did not match. The numerical simulations are available for predicting the voids locations in VPI, but not accurate in calculating the voids content.

  17. 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...... had symptoms equal in severity to those found in men undergoing prostatectomy; 29% and 11% of men in the eighth decade [corrected] had nocturia twice and 3 times or more respectively; 19% complained of urge incontinence. More information on possible treatment is needed....

  18. 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 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...

  19. PVC mixtures’ mechanical properties with the addition of modified calcite as filler

    Directory of Open Access Journals (Sweden)

    Vučinić Dušica R.

    2012-01-01

    Full Text Available In this study mechanical properties of PVC mixtures (PVC, stabilizer, lubricant, filler such as tensile strength, tensile elongation, breaking strength, and breaking elongation were investigated. Unmodified calcite, as well as calcite modified by stearic acid, were used as fillers in wet and dry processes. The PVC mixtures containing the calcite modified by wet procedure have better mechanical properties compared to those with the calcite modified by the dry process. Tensile and breaking strength of the PVC mixture containing the calcite modified with 1.5% stearic acid using wet process, are higher for 2.8% and 5.2%, respectively, compared to the PVC mixture containing the calcite modified with the same amount of acid used in the dry process. The tensile strength difference between the mixtures increases with the increase of the concentration of used stearic acid up to 3%. The strength of PVC mixture with the calcite modified by wet process is 3.1% higher compared to the mixture containing calcite modified by dry process. The results showed that the bonding strength between calcite and the adsorbed organic component affected tensile strength, tensile elongation and breaking strength of the PVC mixtures. The best filler was obtained by wet modification using 1.5% stearic acid solution that provided the formation of a stearate monolayer chemisorbed on calcite. The PVC mixtures containing the calcite modified by wet process using 1.5% stearic acid solution exhibited the best mechanical properties. This calcite was completely hydrophobic with dominant chemically adsorbed surfactant, which means that stearate chemisorbed on calcite provided stronger interaction in the calcite-stearic acid-PVC system.

  20. Development and evaluation of buccoadhesive propranolol hydrochloride tablet formulations: effect of fillers.

    Science.gov (United States)

    Akbari, Jafar; Nokhodchi, Ali; Farid, Djavad; Adrangui, Massoud; Siahi-Shadbad, Mohammad Reza; Saeedi, Majid

    2004-02-01

    The buccal mucosa has been investigated for local and systemic delivery of therapeutic peptides and other drugs that are subjected to first-pass metabolism or are unstable within the rest of the gastrointestinal tract. Propranolol hydrochloride (propranolol HCl) is subjected to first-pass effect, therefore formulation of buccal-adhesive dosage form can circumvent this effect. The effect of lactose (a soluble excipient) and dicalcium phosphate (DCP) (an insoluble excipient) on dissolution rate, kinetic of release and adhesion force of buccal-adhesive tablets of propranolol HCl were evaluated. Each tablet composed of 80 mg propranolol HCl, 80 mg hydroxypropylmethylcellulose (HPMC) K4M, polycarbophil AA1 and lactose or DCP with different ratios. The results showed that the presence of the fillers increased dissolution rate of the drug. The release data also showed that the effect of lactose on the dissolution rate was greater than the DCP. Kinetic release of propranolol HCl from buccal-adhesive matrices was affected by the different ratios of polymers and fillers. The fillers reduced the bioadhesion force and this effect was more considerable in formulation containing DCP. In order to determine the mode of release, the data were analyzed based on the equation Q =kt(n). The results showed that an increase in the concentration of HPMC K4M resulted in a reduction in the value of n. The value of n was not significantly affected by an increase in the concentration of lactose or DCP. The values of n in this study were calculated to be between 0.461 and 0.619, indicating both diffusional release and erosional mechanism.

  1. Epoxy Resin Composite Based on Functional Hybrid Fillers

    Directory of Open Access Journals (Sweden)

    Mariusz Oleksy

    2014-08-01

    Full Text Available A study was carried out involving the filling of epoxy resin (EP with bentonites and silica modified with polyhedral oligomeric silsesquioxane (POSS. The method of homogenization and the type of filler affect the functional and canceling properties of the composites was determined. The filler content ranged from 1.5% to 4.5% by mass. The basic mechanical properties of the hybrid composites were found to improve, and, in particular, there was an increase in tensile strength by 44%, and in Charpy impact strength by 93%. The developed hybrid composites had characteristics typical of polymer nanocomposites modified by clays, with a fine plate morphology of brittle fractures observed by SEM, absence of a plate separation peak in Wide Angles X-ray Scattering (WAXS curves, and an exfoliated structure observed by TEM.

  2. Filler segmentation of SEM paper images based on mathematical morphology.

    Science.gov (United States)

    Ait Kbir, M; Benslimane, Rachid; Princi, Elisabetta; Vicini, Silvia; Pedemonte, Enrico

    2007-07-01

    Recent developments in microscopy and image processing have made digital measurements on high-resolution images of fibrous materials possible. This helps to gain a better understanding of the structure and other properties of the material at micro level. In this paper SEM image segmentation based on mathematical morphology is proposed. In fact, paper models images (Whatman, Murillo, Watercolor, Newsprint paper) selected in the context of the Euro Mediterranean PaperTech Project have different distributions of fibers and fillers, caused by the presence of SiAl and CaCO3 particles. It is a microscopy challenge to make filler particles in the sheet distinguishable from the other components of the paper surface. This objectif is reached here by using switable strutural elements and mathematical morphology operators.

  3. Epoxy Resin Composite Based on Functional Hybrid Fillers

    Science.gov (United States)

    Oleksy, Mariusz; Szwarc-Rzepka, Karolina; Heneczkowski, Maciej; Oliwa, Rafał; Jesionowski, Teofil

    2014-01-01

    A study was carried out involving the filling of epoxy resin (EP) with bentonites and silica modified with polyhedral oligomeric silsesquioxane (POSS). The method of homogenization and the type of filler affect the functional and canceling properties of the composites was determined. The filler content ranged from 1.5% to 4.5% by mass. The basic mechanical properties of the hybrid composites were found to improve, and, in particular, there was an increase in tensile strength by 44%, and in Charpy impact strength by 93%. The developed hybrid composites had characteristics typical of polymer nanocomposites modified by clays, with a fine plate morphology of brittle fractures observed by SEM, absence of a plate separation peak in Wide Angles X-ray Scattering (WAXS) curves, and an exfoliated structure observed by TEM. PMID:28788177

  4. Laser brazing with filler wire for galvanized steel sheets

    Institute of Scientific and Technical Information of China (English)

    Feng Xiaosong; Li Liqun; Chen Yanbin; Zhou Shanbao

    2005-01-01

    The process properties and interface behavior of CO2 laser brazing with automatic wire feed for galvanized steel sheets were investigated , in which the brazing filler metal was CuSi3 and no flux was used. As to the appearance quality of the brazing seams, the roles of the processing parameters, such as brazing speed, wire feeding rate, inclination and feeding direction of the wire, laser power, spot diameter and heating position, were assessed. The further investigation indicates that the behavior of the active elements Si, Mn and Zn are significantly influenced by energy input. At the interface, the microstructure of the base metal was composed of columnar crystals and the acicalar α solid solution was found on the filler metal side.

  5. TRANSVERSELY ISOTROPIC HYPER-ELASTIC MATERIAL RECTANGULAR PLATE WITH VOIDS UNDER A UNIAXIAL EXTENSION

    Institute of Scientific and Technical Information of China (English)

    程昌钧; 任九生

    2003-01-01

    The finite deformation and stress analyses for a transversely isotropic rectangularplate with voids and made of hyper-elastic material with the generalized neo-Hookean strainenergy function under a uniaxial extension are studied. The deformation functions of plateswith voids that are symmetrically distributed in a certain manner are given and the functionsare expressed by two parameters by solving the differential equations. The solution may beapproximately obtained from the minimum potential energy principle. Thus, the analyticsolutions of the deformation and stress of the plate are obtained. The growth of the void.s andthe distribution of stresses along the voids are analyzed and the influences of the degree ofanisotropy, the size of the voids and the distance between the voids are discussed. Thecharacteristics of the growth of the voids and the distribution of stresses of the plates with onevoid, three or five voids are obtained and compared.

  6. Shapes and Sizes of Voids in the LCDM Universe: Excursion Set Approach

    CERN Document Server

    Shandarin, S; Heitmann, K; Habib, S; Shandarin, Sergei; Feldman, Hume A.; Heitmann, Katrin

    2006-01-01

    We study the global distribution and morphology of dark matter voids in a LCDM universe using density fields generated by N-body simulations. Voids are defined as isolated regions of the low-density excursion set specified via density thresholds, the density thresholds being quantified by the corresponding filling factors, i.e., the fraction of the total volume in the excursion set. Our work encompasses a systematic investigation of the void volume function, the volume fraction in voids, and the fitting of voids to corresponding ellipsoids and spheres. We emphasize the relevance of the percolation threshold to the void volume statistics of the density field both in the high redshift, Gaussian random field regime, as well as in the present epoch. By using measures such as the Inverse Porosity, we characterize the quality of ellipsoidal fits to voids, finding that such fits are a poor representation of the larger voids that dominate the volume of the void excursion set.

  7. SURFACE EFFECT ON NANOSIZED VOID GROWTH IN A RIGID-PERFECTLY PLASTIC MATERIAL

    Institute of Scientific and Technical Information of China (English)

    Tong Hui; Yiheng Chen

    2008-01-01

    The influence of the surface effect on the nanosized spherical void growth in a rigid-perfectly plastic material is analyzed and the mechanism of the nanosized void growth with high triaxiality is given. Based on the Rice and Tracey model for a macro void growth, the present model is proposed to account for the nanosized void growth under a uniform remote strain rate field with consideration on the surface effect. It is concluded that the surface effect yields an evident resistant influence on the nanosized void growth. That is, this influence decays as the void radius increases. With high triaxiality, the nanosized void growth is divided into two stages:the initial stage and the mature stage. At the first stage, the void grows slowly and the influence of surface effect is relatively weak, whereas at the second stage, the influene is significant and the void grows drastically.

  8. A mechanistic determination of horizontal flow regime bound using void wave celerity

    Energy Technology Data Exchange (ETDEWEB)

    Park, J.W. [Ajou Univ., Suwon (Korea, Republic of)

    1995-09-01

    The two-phase flow regime boundaries in a horizontal channel has been investigated by using the behavior of the second order void wave celerities. The average two-fluid model has been constituted with closure relations for horizontally stratified and bubbly flows. A vapor phase turbulent stress model for a smooth interface geometry has been included. It is found that the second order waves (i.e., eigenvalues) propagate in opposite direction with almost the same speed when the liquid phase is stationary. Using the well-posedness limit of the two-phase system, the dispersed-stratified flow regime boundary has been modeled. Two-phase Froude number has been theoretically found to be a convenient parameter in quantifying the flow regime boundary as a function of the void fraction. It is found that interaction between void wave celerities become stronger as the two-phase Froude number is reduced. This result should be interpreted as that gravity and the relative velocity are key parameters in determining flow regime boundaries in a horizontal flow. The influence of the vapor phase turbulent stress found to stabilize the flow stratification. This study clearly shows that the average two-fluid model is very effective for a mechanistic determination of horizontal flow regimes if appropriate closure relations are developed.

  9. Gas-liquid Phase Distribution and Void Fraction Measurements Using the MRI

    Science.gov (United States)

    Daidzic, N. E.; Schmidt, E.; Hasan, M. M.; Altobelli, S.

    2004-01-01

    We used a permanent-magnet MRI system to estimate the integral and spatially- and/or temporally-resolved void-fraction distributions and flow patterns in gas-liquid two-phase flows. Air was introduced at the bottom of the stagnant liquid column using an accurate and programmable syringe pump. Air flow rates were varied between 1 and 200 ml/min. The cylindrical non-conducting test tube in which two-phase flow was measured was placed in a 2.67 kGauss MRI with MRT spectrometer/imager. Roughly linear relationship has been obtained for the integral void-fraction, obtained by volume-averaging of the spatially-resolved signals, and the air flow rate in upward direction. The time-averaged spatially-resolved void fraction has also been obtained for the quasi-steady flow of air in a stagnant liquid column. No great accuracy is claimed as this was an exploratory proof-of-concept type of experiment. Preliminary results show that MRI a non-invasive and non-intrusive experimental technique can indeed provide a wealth of different qualitative and quantitative data and is especially well suited for averaged transport processes in adiabatic and diabatic multi-phase and/or multi-component flows.

  10. An evaluation of sodium void reactivity for metal fuel FBR cores

    Energy Technology Data Exchange (ETDEWEB)

    Ohta, Hirokazu; Yokoo, Takeshi [Central Research Inst. of Electric Power Industry, Komae, Tokyo (Japan). Komae Research Lab

    2000-07-01

    The sodium void reactivity in metal fuel FBR cores has been evaluated by a detailed method which takes into account the neutron streaming effects in the fuel subassemblies and the neutron transport corrections in whole-core systems. The neutron streaming effects caused by the heterogeneity of the fuel element structure or the coolant paths were evaluated on the basis of Benoist's anisotropic diffusion coefficient. We clarified that the sodium void reactivity is worth less than $8, even in the 1,000 MWe or 1,500 MWe-class large-scale cores. Further, we also found that, in the case of 1,500 MWe metal fuel FBRs recycling a few percent of minor actinide elements (MA), the sodium void reactivity does not exceed $10 with a suitable design that eliminates the upper and lower axial blankets. These results show that these metal fuel FBRs satisfy the safety criterion ($8-10) for avoiding the prompt criticality in the HCDA events. However, MA enrichment should be controlled to less than about two per cent, when the axial blanket is loaded to gain higher breeding performance. (author)

  11. Mycobacterium chelonae Facial Infections Following Injection of Dermal Filler

    OpenAIRE

    Rodriguez, Jan M.; Xie, Yingda L.; Winthrop, Kevin L; Schafer, Sean; Sehdev, Paul; Solomon, Joel; Jensen, Bette; Toney, Nadege C.; Lewis, Paul F.

    2013-01-01

    A cluster of 3 facial Mycobacterium chelonae infections occurred after cosmetic dermal filler injections at a plastic surgery clinic. Pulsed-field gel electrophoresis showed that M chelonae isolated from the clinic tap water were identical to the patient wound isolates. Review of injection procedures identified application of nonsterile ice to the skin prior to injection as a possible source of M chelonae. Surveys of regional laboratories and a national plastic surgery listserv identified no ...

  12. The influence of filler particles on space charge measurements

    Energy Technology Data Exchange (ETDEWEB)

    Hole, Stephane [Laboratoire des Instruments et Systemes d' Ile de France, Universite Pierre et Marie Curie - 10, rue Vauquelin, 75005 Paris, France (France); Sylvestre, Alain [Laboratoire d' lectrostatique et des Materiaux Dielectriques, CNRS UMR5517 - 25, avenue des Martyrs, BP 166, 38042 Grenoble Cedex 9 (France); Rowe, Stephen [Direction des Recherches Materiaux, Schneider Electric SA - 20, rue Henri Tarze, 38050 Grenoble Cedex (France)

    2004-07-07

    The effects of filler particles on the signal measured using the pressure-wave-propagation method to determine the space charge distribution are analysed. A special test sample geometry is used to classify the influence of particles, and in particular, the role of piezoelectricity is discussed. Applications with Epoxy resin samples loaded either by silica or alumina particles are presented. Silica particles are shown to exhibit piezoelectricity which strongly modifies the measured signals.

  13. Image analysis of aggregate,mastic and air void phases for asphalt mixture%Image analysis of aggregate, mastic and air void phases for asphalt mixture

    Institute of Scientific and Technical Information of China (English)

    ADHIKARI Sanjeev; YOU Zhan-ping; HAO Pei-wen; WANG Hai-nian

    2013-01-01

    The shape characterization and spatial distribution of aggregate,mastic and air void phases for asphalt mixture were analyzed.Three air void percentage asphalt mixtures,4%,7% and 8%,respectively,were cut into cross sections and polished.X-ray scanning microscope was used to capture aggregate,mastic,air void phase by the image.The average of polygon diameter was chosen as a threshold to determine which aggregates would be retained on a given sieve.The aggregate morphological image from scanned image was utilized by digital image processing method to calculate the gradation of aggregate and simulate the real gradation.Analysis result shows that the air void of asphalt mixture has influence on the correlation between calculation gradation and actual gradation.When comparing 4.75 mm sieve size of 4%,7% and 8% air void asphalt mixtures,7% air void asphalt mixture has 55% higher than actual size gradation,8% air void asphalt mixture has 8% higher than actual size gradation,and 4% air void asphalt mixture has 3.71% lower than actual size gradation.4% air void asphalt mixture has the best correlation between calculation gradation and actual gradation comparing to other specimens.The air void percentage of asphalt mixture has no obvious influence on the air void orientation,and three asphalt mixtures show the similar air orientation along the same direction.4 tabs,7 figs,17 refs.

  14. Hydrodynamic parameters of mesh fillers relevant to miniature regenerative cryocoolers

    Science.gov (United States)

    Landrum, E. C.; Conrad, T. J.; Ghiaasiaan, S. M.; Kirkconnell, Carl S.

    2010-06-01

    Directional hydrodynamic parameters of two fine-mesh porous materials that are suitable for miniature regenerative cryocoolers were studied under steady and oscillating flows of helium. These materials included stacked discs of #635 stainless steel (wire diameter of 20.3 μm) and #325 phosphor bronze (wire diameter of 35.6 μm) wire mesh screens, which are among the commercially available fillers for use in small-scale regenerators and heat exchangers, respectively. Experiments were performed in test sections in which pressure variations across these fillers, in the axial and lateral (radial) directions, were measured under steady and oscillatory flows. The directional permeability and Forchheimer's inertial coefficient were then obtained by using a Computational Fluid Dynamics (CFD)-assisted method. The oscillatory flow experiments covered a frequency range of 50-200 Hz. The results confirmed the importance of anisotropy in the mesh screen fillers, and indicated differences between the directional hydrodynamic resistance parameters for steady and oscillating flow regimes.

  15. NANOSCALE BOEHMITE FILLER FOR CORROSION AND WEAR RESISTANT POLYPHENYLENESULFIDE COATINGS.

    Energy Technology Data Exchange (ETDEWEB)

    SUGAMA,T.

    2003-06-26

    The authors evaluated the usefulness of nanoscale boehmite crystals as a filler for anti-wear and anti-corrosion polyphenylenesulfide (PPS) coatings exposed to a very harsh, 300 C corrosive geothermal environment. The boehmite fillers dispersed uniformly into the PPS coating, conferring two advanced properties: First, they reduced markedly the rate of blasting wear; second, they increased the PPS's glass transition temperature and thermal decomposition temperature. The wear rate of PPS surfaces was reduced three times when 5wt% boehmite was incorporated into the PPS. During exposure for 15 days at 300 C, the PPS underwent hydrothermal oxidation, leading to the substitution of sulfide linkages by the sulfite linkages. However, such molecular alteration did not significantly diminish the ability of the coating to protect carbon steel against corrosion. In fact, PPS coating filled with boehmite of {le} 5wt% adequately mitigated its corrosion in brine at 300 C. One concern in using this filler was that it absorbs brine. Thus, adding an excess amount of boehmite was detrimental to achieving the maximum protection afforded by the coatings.

  16. Injectable facial fillers: imaging features, complications, and diagnostic pitfalls at MRI and PET CT.

    Science.gov (United States)

    Mundada, Pravin; Kohler, Romain; Boudabbous, Sana; Toutous Trellu, Laurence; Platon, Alexandra; Becker, Minerva

    2017-10-04

    Injectable fillers are widely used for facial rejuvenation, correction of disabling volumetric fat loss in HIV-associated facial lipoatrophy, Romberg disease, and post-traumatic facial disfiguring. The purpose of this article is to acquaint the reader with the anatomy of facial fat compartments, as well as with the properties and key imaging features of commonly used facial fillers, filler-related complications, interpretation pitfalls, and dermatologic conditions mimicking filler-related complications. The distribution of facial fillers is characteristic and depends on the anatomy of the superficial fat compartments. Silicone has signature MRI features, calcium hydroxyapatite has characteristic calcifications, whereas other injectable fillers have overlapping imaging features. Most fillers (hyaluronic acid, collagen, and polyalkylimide-polyacrylamide hydrogels) have signal intensity patterns compatible with high water content. On PET-CT, most fillers show physiologic high FDG uptake, which should not be confounded with pathology. Abscess, cellulitis, non-inflammatory nodules, and foreign body granulomas are the most common filler-related complications, and imaging can help in the differential diagnosis. Diffusion weighted imaging helps in detecting a malignant lesion masked by injected facial fillers. Awareness of imaging features of facial fillers and their complications helps to avoid misinterpretation of MRI, and PET-CT scans and facilitates therapeutic decisions in unclear clinical cases. • Facial fillers are common incidental findings on MRI and PET-CT scans. • They have a characteristic appearance and typical anatomic distribution • Although considered as safe, facial filler injections are associated with several complications • As they may mask malignancy, knowledge of typical imaging features is mandatory. • MRI is a problem-solving tool for unclear cases.

  17. Impact on liquids : void collapse and jet formation

    NARCIS (Netherlands)

    Gekle, Stephan

    2009-01-01

    A spectacular example of free surface flow is the impact of a solid object on a liquid: At impact a “crown” splash is created and a surface cavity (void) emerges which immediately starts to collapse due to the hydrostatic pressure of the surrounding liquid. Eventually the cavity closes in a single

  18. Void growth to coalescence in a non-local material

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof

    The size-effect in metals containing distributed spherical voids is analyzed numerically using a finite strain generalization of a length scale dependent plasticity theory. Results are obtained for stress-triaxialities relevant in front of a crack tip in an elastic-plastic metal. The influence...

  19. Void growth to coalescence in a non-local material

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof

    2008-01-01

    The size-effect in metals containing distributed spherical voids is analyzed numerically using a finite strain generalization of a length scale dependent plasticity theory. Results are obtained for stress-triaxialities relevant in front of a crack tip in an elastic-plastic metal. The influence...

  20. Kinetic Monte Carlo simulations of void lattice formation during irradiation

    Science.gov (United States)

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

    2003-11-01

    Over the last decade, molecular dynamics simulations of displacement cascades have revealed that glissile clusters of self-interstitial crowdions are formed directly in cascades and that they migrate one-dimensionally along close-packed directions with extremely low activation energies. Occasionally, under various conditions, a crowdion cluster can change its Burgers vector and glide along a different close-packed direction. The recently developed production bias model (PBM) of microstructure evolution under irradiation has been structured specifically to take into account the unique properties of the vacancy and interstitial clusters produced in the cascades. Atomic-scale kinetic Monte Carlo (KMC) simulations have played a useful role in understanding the defect reaction kinetics of one-dimensionally migrating crowdion clusters as a function of the frequency of direction changes. This has made it possible to incorporate the migration properties of crowdion clusters and changes in reaction kinetics into the PBM. In the present paper we utilize similar KMC simulations to investigate the significant role that crowdion clusters can play in the formation and stability of void lattices. The creation of stable void lattices, starting from a random distribution of voids, is simulated by a KMC model in which vacancies migrate three-dimensionally and self-interstitial atom (SIA) clusters migrate one-dimensionally, interrupted by directional changes. The necessity of both one-dimensional migration and Burgers vectors changes of SIA clusters for the production of stable void lattices is demonstrated, and the effects of the frequency of Burgers vector changes are described.

  1. A cosmic watershed : the WVF void detection technique

    NARCIS (Netherlands)

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

    2007-01-01

    On megaparsec scales the Universe is permeated by an intricate filigree of clusters, filaments, sheets and voids, the cosmic web. For the understanding of its dynamical and hierarchical history it is crucial to identify objectively its complex morphological components. One of the most characteristic

  2. Structural control of void formation in dual phase steels

    DEFF Research Database (Denmark)

    Azuma, Masafumi

    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...

  3. Impact on liquids : void collapse and jet formation

    NARCIS (Netherlands)

    Gekle, Stephan

    2009-01-01

    A spectacular example of free surface flow is the impact of a solid object on a liquid: At impact a “crown” splash is created and a surface cavity (void) emerges which immediately starts to collapse due to the hydrostatic pressure of the surrounding liquid. Eventually the cavity closes in a single p

  4. Predictive efficacy of radioisotope voiding cystography for renal outcome

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seok Ki; Lee, Dong Soo; Kim, Kwang Myeung; Choi, Whang; Chung, June Key; Lee, Myung Chul [Seoul National Univ. College of Medicine, Seoul (Korea, Republic of)

    2000-04-01

    As vesicoureteral reflux (VUR) could lead to renal functional deterioration when combined with urinary tract infection, we need to decide whether operative anti-reflux treatment should be performed at the time of diagnosis of VUR. Predictive value of radioisotope voiding cystography (RIVCG) for renal outcome was tested. In 35 children (18 males, 17 females), radiologic voiding cystoure-thrography (VCU), RIVCG and DMSA scan were performed. Change in renal function was evaluated using the follow-up DMSA scan, ultrasonography, and clinical information. Discriminant analysis was performed using individual or integrated variables such as reflux amount and extent at each phase of voiding on RIVCG, in addition to age, gender and cortical defect on DMSA scan at the time of diagnosis. Discriminant function was composed and its performance was examined. Reflux extent at the filling phase and reflux amount and extent at postvoiding phase had a significant prognostic value. Total reflux amount was a composite variable to predict prognosis. Discriminant function composed of reflux extent at the filling phase and reflux amount and extent at postvoiding phase showed better positive predictive value and specificity than conventional reflux grading. RIVCG could predict renal outcome by disclosing characteristic reflux pattern during various voiding phases.

  5. The Effect of Random Voids in the Modified Gurson Model

    Science.gov (United States)

    Fei, Huiyang; Yazzie, Kyle; Chawla, Nikhilesh; Jiang, Hanqing

    2012-02-01

    The porous plasticity model (usually referred to as the Gurson-Tvergaard-Needleman model or modified Gurson model) has been widely used in the study of microvoid-induced ductile fracture. In this paper, we studied the effects of random voids on the porous plasticity model. Finite-element simulations were conducted to study a copper/tin/copper joint bar under uniaxial tension using the commercial finite-element package ABAQUS. A randomly distributed initial void volume fraction with different types of distribution was introduced, and the effects of this randomness on the crack path and macroscopic stress-strain behavior were studied. It was found that consideration of the random voids is able to capture more detailed and localized deformation features, such as different crack paths and different ultimate tensile strengths, and meanwhile does not change the macroscopic stress-strain behavior. It seems that the random voids are able to qualitatively explain the scattered observations in experiments while keeping the macroscopic measurements consistent.

  6. A halo bias function measured deeply into voids without stochasticity

    CERN Document Server

    Neyrinck, Mark C; Jeong, Donghui; Wang, Xin

    2013-01-01

    We study the relationship between dark-matter haloes and matter in the MIP N-body simulation ensemble, which allows precision measurements of this relationship, even deeply into voids. What enables this is a lack of discreteness, stochasticity, and exclusion, achieved by averaging over hundreds of possible sets of initial small-scale modes, while holding fixed large-scale modes that give the cosmic web. We find (i) that dark-matter-halo formation is greatly suppressed in voids; there is an exponential downturn at low densities in the otherwise power-law matter-to-halo density bias function. Thus, the rarity of haloes in voids is akin to the rarity of the largest clusters, and their abundance is quite sensitive to cosmological parameters. The exponential downturn appears both in an excursion-set model, and in a new model in which fluctuations evolve in voids as in an open universe with an effective Omega_m proportional to a large-scale density. We also find that (ii) haloes typically populate the average halo-...

  7. 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...

  8. Excursion Sets and Non-Gaussian Void Statistics

    CERN Document Server

    D'Amico, Guido; Noreña, Jorge; Paranjape, Aseem

    2010-01-01

    Primordial non-Gaussianity (NG) affects the large scale structure (LSS) of the universe by leaving an imprint on the distribution of matter at late times. Much attention has been focused on using the distribution of collapsed objects (i.e. dark matter halos and the galaxies and galaxy clusters that reside in them) to probe primordial NG. An equally interesting and complementary probe however is the abundance of extended underdense regions or voids in the LSS. The calculation of the abundance of voids using the excursion set formalism in the presence of primordial NG is subject to the same technical issues as the one for halos, which were discussed e.g. in arXiv:1005.1203. However, unlike the excursion set problem for halos which involved random walks in the presence of one barrier $\\delta_c$, the void excursion set problem involves two barriers $\\delta_v$ and $\\delta_c$. This leads to a new complication introduced by what is called the "void-in-cloud" effect discussed in the literature, which is unique to the...

  9. Impact on liquids : void collapse and jet formation

    NARCIS (Netherlands)

    Gekle, Stephan

    2009-01-01

    A spectacular example of free surface flow is the impact of a solid object on a liquid: At impact a “crown” splash is created and a surface cavity (void) emerges which immediately starts to collapse due to the hydrostatic pressure of the surrounding liquid. Eventually the cavity closes in a single p

  10. Effect of void structure of photocatalyst paper on VOC decomposition.

    Science.gov (United States)

    Fukahori, Shuji; Iguchi, Yumi; Ichiura, Hideaki; Kitaoka, Takuya; Tanaka, Hiroo; Wariishi, Hiroyuki

    2007-02-01

    TiO2 powder-containing paper composites, called TiO2 paper, were prepared by a papermaking technique, and their photocatalytic efficiency was investigated. The TiO2 paper has a porous structure originating from the layered pulp fiber network, with TiO2 powders scattered on the fiber matrix. Under UV irradiation, the TiO2 paper decomposed gaseous acetaldehyde more effectively than powdery TiO2 and a pulp/TiO2 mixture not in paper form. Scanning electron microscopy and mercury intrusion analysis revealed that the TiO2 paper had characteristic unique voids ca. 10 microm in diameter, which might have contributed to the improved photocatalytic performance. TiO2 paper composites having different void structures were prepared by using beaten pulp fibers with different degrees of freeness and/or ceramic fibers. The photodecomposition efficiency was affected by the void structure of the photocatalyst paper, and the initial degradation rate of acetaldehyde increased with an increase in the total pore volume of TiO2 paper. The paper voids presumably provided suitable conditions for TiO2 catalysis, resulting in higher photocatalytic performance by TiO2 paper than by TiO2 powder and a pulp/TiO2 mixture not in paper form.

  11. 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 interact

  12. 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.

  13. An HI survey of the bootes void; 2, the analysis

    CERN Document Server

    Szomoru, A; Gregg, M D; Strauss, M A

    1995-01-01

    We discuss the results of a VLA HI survey of the Bootes void and compare the distribution and HI properties of the void galaxies to those of galaxies found in a survey of regions of mean cosmic density. The Bootes survey covers 1100 Mpc^{3}, or \\sim 1\\% of the volume of the void and consists of 24 cubes of typically 2 Mpc * 2 Mpc * 1280 km/s, centered on optically known galaxies. Sixteen targets were detected in HI; 18 previously uncataloged objects were discovered directly in HI. The control sample consists of 12 cubes centered on IRAS selected galaxies with FIR luminosities similar to those of the Bootes targets and located in regions of 1 to 2 times the cosmic mean density. In addition to the 12 targets 29 companions were detected in HI. We find that the number of galaxies within 1 Mpc of the targets is the same to within a factor of two for void and control samples, and thus that the small scale clustering of galaxies is the same in regions that differ by a factor of \\sim 6 in density on larger scales. A ...

  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. 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.

  16. Answers from the Void: VIDE and its Applications

    Science.gov (United States)

    Sutter, P. M.; Hamaus, N.; Pisani, A.; Lavaux, G.; Wandelt, B. D.

    2016-10-01

    We discuss various applications ofvide, the Void IDentification and Examination toolkit, anopen-source Python/C++ code for finding cosmic voids in galaxy redshift surveysand $N$-body simulations.Based on a substantially enhanced version of ZOBOV, vide not only finds voids, but alsosummarizes their properties, extracts statisticalinformation, and providesa Python-based platform for more detailed analysis, such asmanipulating void catalogs and particle members, filtering, plotting,computing clustering statistics, stacking, comparing catalogs, andfitting density profiles.vide also provides significant additional functionality forpre-processing inputs: for example, vide can work with volume- ormagnitude-limited galaxy samples with arbitrary survey geometries,or darkmatter particles or halo catalogs in a variety of common formats.It can also randomly subsample inputsand includes a Halo Occupation Distribution model forconstructing mock galaxy populations.vide has been used for a wide variety of applications, fromdiscovering a universal density profile to estimatingprimordial magnetic fields, andis publicly available athttp://bitbucket.org/cosmicvoids/vide\\_publicandhttp://www.cosmicvoids.net.

  17. The Instability of Void Fraction Waves in Vertical Gas—Liquid Two—Phase Flow

    Institute of Scientific and Technical Information of China (English)

    BaojiangSUN; DachunYAN; 等

    1999-01-01

    The measuring and analyzing results of void fraction waves in different flow regimes show that the propagating velocity of void fraction waves depends on flow regimes and mean void fraction.The disturbance at some frequencies can enhance the void fraction wave velocity.Non-linear analysis show that the instability process of bubble flow is a chaotic process.Before the bubbly flow transits to cap-bubbly flow the growth rate of void fraction waves becomes the maximum value when the disturbance frequency is around the main frequency of void fraction waves.

  18. Effects of Cure Pressure Induced Voids on the Mechanical Strength of Carbon/Epoxy Laminates

    Institute of Scientific and Technical Information of China (English)

    Ling LIU; Boming ZHANG; Zhanjun WU; Dianfu WANG

    2005-01-01

    This work aims at designing a set of curing pressure routes to produce laminates with various void contents. The effects of various consolidation pressures resulting in different void contents on mechanical strength of carbon/epoxy laminates have been examined. Characterization of the voids, in terms of void volume fraction, void distribution,size, and shape, was performed by standard test, ultrasonic inspection and metallographic analysis. The interlaminar shear strength was measured by the short-beam method. An empirical model was used to predict the strength vs porosity. The predicted strengths conform well with the experimental data and voids were found to be uniformly distributed throughout the laminate.

  19. Detection of atomic scale changes in the free volume void size of three-dimensional colorectal cancer cell culture using positron annihilation lifetime spectroscopy.

    Science.gov (United States)

    Axpe, Eneko; Lopez-Euba, Tamara; Castellanos-Rubio, Ainara; Merida, David; Garcia, Jose Angel; Plaza-Izurieta, Leticia; Fernandez-Jimenez, Nora; Plazaola, Fernando; Bilbao, Jose Ramon

    2014-01-01

    Positron annihilation lifetime spectroscopy (PALS) provides a direct measurement of the free volume void sizes in polymers and biological systems. This free volume is critical in explaining and understanding physical and mechanical properties of polymers. Moreover, PALS has been recently proposed as a potential tool in detecting cancer at early stages, probing the differences in the subnanometer scale free volume voids between cancerous/healthy skin samples of the same patient. Despite several investigations on free volume in complex cancerous tissues, no positron annihilation studies of living cancer cell cultures have been reported. We demonstrate that PALS can be applied to the study in human living 3D cell cultures. The technique is also capable to detect atomic scale changes in the size of the free volume voids due to the biological responses to TGF-β. PALS may be developed to characterize the effect of different culture conditions in the free volume voids of cells grown in vitro.

  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. Reactive hydroxyapatite fillers for pectin biocomposites.

    Science.gov (United States)

    Munarin, Fabiola; Petrini, Paola; Barcellona, Giulia; Roversi, Tommaso; Piazza, Laura; Visai, Livia; Tanzi, Maria Cristina

    2014-12-01

    In this work, a novel injectable biocomposite hydrogel is produced by internal gelation, using pectin as organic matrix and hydroxyapatite either as crosslinking agent and inorganic reinforcement. Tunable gelling kinetics and rheological properties are obtained varying the hydrogels' composition, with the final aim of developing systems for cell immobilization. The reversibility by dissolution of pectin-hydroxyapatite hydrogels is achieved with saline solutions, to possibly accelerate the release of the cells or active agents immobilized. Texture analysis confirms the possibility of extruding the biocomposites from needles with diameters from 20 G to 30 G, indicating that they can be implanted with minimally-invasive approaches, minimizing the pain during injection and the side effects of the open surgery. L929 fibroblasts entrapped in the hydrogels survive to the immobilization procedure and exhibit high cell viability. On the overall, these systems result to be suitable supports for the immobilization of cells for tissue regeneration applications.

  2. Effect of a carbonated HAP/β-glucan composite bone substitute on healing of drilled bone voids in the proximal tibial metaphysis of rabbits

    Energy Technology Data Exchange (ETDEWEB)

    Borkowski, Leszek, E-mail: leszek.borkowski@umlub.pl [Department of Biochemistry and Biotechnology, Medical University of Lublin, Chodźki 1, 20-093 Lublin (Poland); Pawłowska, Marta; Radzki, Radosław P.; Bieńko, Marek [Department of Animal Physiology, University of Life Sciences in Lublin, Akademicka 12, 20-033 Lublin (Poland); Polkowska, Izabela [Department and Clinic of Animal Surgery, University of Life Sciences in Lublin, Głęboka 30, 20-612 Lublin (Poland); Belcarz, Anna [Department of Biochemistry and Biotechnology, Medical University of Lublin, Chodźki 1, 20-093 Lublin (Poland); Karpiński, Mirosław [Department of Companion and Wildlife Animals, University of Life Sciences in Lublin, Akademicka 13, 20-950 Lublin (Poland); Słowik, Tymoteusz [Independent Radiology Unit at Lublin Small Animals Medical Centre, Stefczyka 11, 20-151 Lublin (Poland); Matuszewski, Łukasz [Children' s Orthopaedic Clinic and Rehabilitation Department, Medical University of Lublin, Chodzki 2, 20-093 Lublin (Poland); Ślósarczyk, Anna [Faculty of Materials Science and Ceramics, AGH-University of Science and Technology, Mickiewicza 30, 30-059 Krakow (Poland); Ginalska, Grażyna [Department of Biochemistry and Biotechnology, Medical University of Lublin, Chodźki 1, 20-093 Lublin (Poland)

    2015-08-01

    A novel elastic hydroxyapatite-based composite of high surgical handiness has been developed. Its potential application in orthopedics as a filler of bone defects has been studied. The biomaterial was composed of carbonated hydroxyapatite (CHAP) granules and polysaccharide polymer (β-1,3-glucan). Cylinders of 4 mm in diameter and 6 mm in length were implanted into bone cavities created in the proximal metaphysis of tibiae of 24 New Zealand white rabbits. 18 sham-operated animals were used as controls. After 1, 3 or 6 months, the rabbits were euthanized, the bones were harvested and subjected to analysis. Radiological images and histological sections revealed integration of implants with bone tissue with no signs of graft rejection. Peripheral quantitative computed tomography (pQCT) indicated the stimulating effect of the biomaterial on bone formation and mineralization. Densitometry (DXA) analysis suggested that biomineralization of bones was preceded by bioresorption and gradual disappearance of porous ceramic granules. The findings suggest that the CHAP–glucan composite material enables regeneration of bone tissue and could serve as a bone defect filler. - Highlights: • Highly porous carbonate HAP granules and β-1,3-glucan were used to fill bone voids. • Critical size defects of rabbit tibiae were filled with the composite scaffolds. • Biocompatibility, mineralization and osseointegration of implants were examined. • Histological analysis indicated a high biocompatibility of composite grafts. • We report penetration of bony tissue into implants and advanced osseointegration.

  3. A constitutive model for elastoplastic solids containing primary and secondary voids

    Science.gov (United States)

    Fabrègue, D.; Pardoen, T.

    In many ductile metallic alloys, the damage process controlled by the growth and coalescence of primary voids nucleated on particles with a size varying typically between 1 and 100 μm, is affected by the growth of much smaller secondary voids nucleated on inclusions with a size varying typically between 0.1 and 3 μm. The goal of this work is first to quantify the potential effect of the growth of these secondary voids on the coalescence of primary voids using finite element (FE) unit cell calculations and second to formulate a new constitutive model incorporating this effect. The nucleation and growth of secondary voids do essentially not affect the growth of the primary voids but mainly accelerate the void coalescence process. The drop of the ductility caused by the presence of secondary voids increases if the nucleation strain decreases and/or if their volume fraction increases and/or if the primary voids are flat. A strong coupling is indeed observed between the shape of the primary voids and the growth of the second population enhancing the anisotropy of the ductility induced by void shape effects. The new micromechanics-based coalescence condition for internal necking introduces the softening induced by secondary voids growing in the ligament between two primary voids. The FE cell calculations were used to guide and assess the development of this model. The use of the coalescence condition relies on a closed-form model for estimating the evolution of the secondary voids in the vicinity of a primary cavity. This coalescence criterion is connected to an extended Gurson model for the first population including the effect of the void aspect ratio. With respect to classical models for single void population, this new constitutive model improves the predictive potential of damage constitutive models devoted to ductile metal while requiring only two new parameters, i.e. the initial porosity of second population and a void nucleation stress, without any additional

  4. 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.

  5. Comparison of voiding cystourethrography and urosonography with second-generation contrast agents in simultaneous prospective study

    Science.gov (United States)

    Świętoń, Dominik; Rybczyńska, Dorota; Czarniak, Piotr; Szarmach, Arkadiusz; Kaszubowski, Mariusz; Szurowska, Edyta

    2016-01-01

    Background The invasiveness and exposure to radiation in voiding cystourethrography led to the introduction of alternative methods of diagnosis of vesicoureteral reflux, including contrast enhanced voiding urosonography. While there is a limited number of studies comparing these methods using new generation ultrasound contrast agents, none of them compared both methods simultaneously. This study is aimed at assessing agreement between contrast enhanced voiding urosonography with second-generation ultrasound contrast agents and voiding cystourethrography. Methods From April 2013 to May 2014, 83 children (37 female and 46 male), mean age 3.5 years, age range from 1 month to 17.5 years, underwent prospective simultaneous assessment by contrast enhanced voiding urosonography and voiding cystourethrography, with a total of 166 uretero-renal units evaluated. Results The sensitivity of voiding cystourethrography and contrast enhanced voiding urosonography were comparable, amounting to 88%, however, neither reached 100% for the entire studied population. The negative predictive value of voiding urosonography and voiding cystourethrography was 97%, and there was no difference between both methods. Conclusion Voiding cystourethrography and contrast enhanced voiding urosonography are comparable methods in diagnosis of vesicoureteral reflux, and can be performed alternatively. However, some limitations of contrast enhanced voiding urosonography must be remembered.

  6. YbF3/SiO2 Fillers as Radiopacifiers in a Dental Adhesive Resin

    Institute of Scientific and Technical Information of China (English)

    Neftali L V Carreno; Thiago C S Oliveira; Evandro Piva; Fernanda B Leal; Giana S Lima; Marcelo D Moncks; Cristiane W Raubach; Fabrcio A Ogliari

    2012-01-01

    The objective of this study was to evaluate the effect of functionalizing a dental adhesive resin with YbF3/SiO2 fillers for use as radiopacifiers. Particles of YbF3/SiO2 were obtained with the high-energy mechanical milling method and characterized by both physical and chemical methods. After characterization, the particles were sieved and silanized prior to being incorporated into an adhesive resin. The stability of the particle suspension was then evaluated. After light activation, the radiopacity, degree of conversion, flexural strength and elastic modulus were determined. The dental adhesive resins with 10 and 15 wt%of filler provided satisfactory radiopacity, while flexural strength and elastic modulus were not affected. The degree of conver-sion was statistically lower than that of the control (p<0.05). The method used for incorporating the tested ytterbium fluoride/silicon dioxide particles at concentrations of 10 and 15 wt%was shown to be feasible for the development of a radiopaque dental adhesive system.

  7. Effect of Conductive Inorganic Fillers on Space Charge Accumulation Characteristics in Cross-linked Polyethylene

    Science.gov (United States)

    Harada, Hiroshi; Hayashi, Nobuya; Tanaka, Yasuhiro; Maeno, Takashi; Mizuno, Takehiko; Takahashi, Tohru

    We have observed space charge profiles in cross-linked polyethylene (XLPE) under dc high electric field using the PEA (pulsed electro-acoustic) system to study the relationship between space charge behavior and dielectric breakdown. In our previous research work, we have found that a large amount of, so called, packet-like charge generates in low density polyethylene (LDPE) under high dc electric field of more than 100 kV/mm. The packet-like charge enhances the electric field locally in bulk of the sample, and then finally it leads a breakdown. On the other hand, a new type of XLPE which was made through adding conductive inorganic fillers, shows a good dc dielectric breakdown characteristic and high volume resistivity under dc stress. In this report, we tried to observe the space charge behavior under high dc electric field in this material. From the results, it is found that the charge injection is effectively suppressed by adding only a small amount of conductive inorganic fillers to XLPE.

  8. Brazing characteristics of a Zr-Ti-Cu-Fe eutectic alloy filler metal for Zircaloy-4

    Science.gov (United States)

    Lee, Jung G.; Lim, C. H.; Kim, K. H.; Park, S. S.; Lee, M. K.; Rhee, C. K.

    2013-10-01

    A Zr-Ti-Cu-Fe quaternary eutectic alloy was employed as a new Be-free brazing filler metal for Zircaloy-4 to supersede physically vapor-deposited Be coatings used conventionally with several disadvantages. The quaternary eutectic composition of Zr58Ti16Cu10Fe16 (at.%) showing a low melting temperature range from 832 °C to 853 °C was designed by a partial substitution of Zr with Ti based on a Zr-Cu-Fe ternary eutectic system. By applying an alloy ribbon with the determined composition, a highly reliable joint was obtained with a homogeneous formation of predominantly grown α-Zr phases owing to a complete isothermal solidification, exhibiting strength higher than that of Zircaloy-4. The homogenization of the joint was rate-controlled by the diffusion of the filler elements (Ti, Cu, and Fe) into the Zircaloy-4 base metal, and the detrimental segregation of the Zr2Fe phase in the central zone was completely eliminated by an isothermal holding at a brazing temperature of 920 °C for 10 min.

  9. Brazing characteristics of a Zr–Ti–Cu–Fe eutectic alloy filler metal for Zircaloy-4

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jung G.; Lim, C.H. [Nuclear Materials Development Division, Korea Atomic Energy Research Institute (KAERI), Yuseong, Daejeon 305-353 (Korea, Republic of); Kim, K.H. [University of Science and Technology, Nuclear Materials Development Division, Korea Atomic Energy Research Institute (KAERI), Yuseong, Daejeon 305-353 (Korea, Republic of); Park, S.S. [School of Mechanical and Advanced Materials Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798 (Korea, Republic of); Lee, M.K., E-mail: leeminku@kaeri.re.kr [Nuclear Materials Development Division, Korea Atomic Energy Research Institute (KAERI), Yuseong, Daejeon 305-353 (Korea, Republic of); Rhee, C.K. [Nuclear Materials Development Division, Korea Atomic Energy Research Institute (KAERI), Yuseong, Daejeon 305-353 (Korea, Republic of)

    2013-10-15

    A Zr–Ti–Cu–Fe quaternary eutectic alloy was employed as a new Be-free brazing filler metal for Zircaloy-4 to supersede physically vapor-deposited Be coatings used conventionally with several disadvantages. The quaternary eutectic composition of Zr{sub 58}Ti{sub 16}Cu{sub 10}Fe{sub 16} (at.%) showing a low melting temperature range from 832 °C to 853 °C was designed by a partial substitution of Zr with Ti based on a Zr–Cu–Fe ternary eutectic system. By applying an alloy ribbon with the determined composition, a highly reliable joint was obtained with a homogeneous formation of predominantly grown α-Zr phases owing to a complete isothermal solidification, exhibiting strength higher than that of Zircaloy-4. The homogenization of the joint was rate-controlled by the diffusion of the filler elements (Ti, Cu, and Fe) into the Zircaloy-4 base metal, and the detrimental segregation of the Zr{sub 2}Fe phase in the central zone was completely eliminated by an isothermal holding at a brazing temperature of 920 °C for 10 min.

  10. In Situ Void Fraction and Gas Volume in Hanford Tank 241-SY-101 as Measured with the Void Fraction Instrument

    Energy Technology Data Exchange (ETDEWEB)

    CW Stewart; G Chen; JM Alzheimer; PA Meyer

    1998-11-10

    The void fraction instrument (WI) was deployed in Tank 241-SY-101 three times in 1998 to confm and locate the retained gas (void) postulated to be causing the accelerating waste level rise observed since 1995. The design, operation, and data reduction model of the WI are described along with validation testing and potential sources of uncertainty. The test plans, field observations and void measurements are described in detail, including the total gas volume calculations and the gas volume model. Based on 1998 data, the void fraction averaged 0.013 i 0.001 in the mixed slurry and 0.30 ~ 0.04 in the crust. This gives gas volumes (at standard pressure and temperature) of 87 t 9 scm in the slurry and 138 ~ 22 scm in the crust for a total retained gas volume of221 *25 scm. This represents an increase of about 74 scm in the crust and a decrease of about 34 scm in the slurry from 1994/95 results. The overall conclusion is that the gas retention is occurring mainly in the crust layer and there is very little gas in the mixed slurry and loosely settled layers below. New insights on crust behavior are also revealed.

  11. Investigation of Using Waste Welded Tuff Material as Mineral Filler in Asphalt Concrete

    Directory of Open Access Journals (Sweden)

    Sebnem KARAHANCER

    2016-08-01

    Full Text Available In this paper, the welded tuff waste- known as koyke in Isparta region - was used in the hot mix asphalt (HMA as mineral filler for reduction of the moisture susceptibility of HMA. Optimum binder content was assessed with Marshall Design Method. First of all, welded tuff was substituted as filler with limestone filler in proportion of 50% and 100%. After that Marshall Stability test was performed on specimens. The results showed that the 50% substitution was more effective than the 100% substitution. Therefore, welded tuff was substituted with limestone filler in proportion of 25%, 50%, 65% and 75%. Next, Indirect Tensile Strength test was practiced on the fabricated specimens and the results were assessed. According to the Indirect Tensile Strength results, welded tuff with 65% was given higher strength than the limestone filler. As a result, it has come up that welded tuff can be used as mineral filler in the hot mix asphalt.

  12. New fillers under consideration: what is the future of injectable aesthetics?

    Science.gov (United States)

    Rivkin, Alexander

    2009-05-01

    The past 5 years in the United States have seen an explosion in the popularity of noninvasive aesthetic procedures. Not only have fillers and Botox turned out to be fantastically reliable and effective aesthetic tools, but also they have vastly expanded the accessibility of cosmetic procedures. Our cosmetic filler options are growing quickly as more and more fillers are coming before the U.S. Food and Drug Administration (FDA), seeking entry into the lucrative U.S. market. This article outlines the approval process that foreign fillers go through in their home countries and gives an idea of the fillers that are currently under consideration by the FDA. As our armamentarium of injectable fillers grows, it will be essential to know each product's strengths and weaknesses so that we can provide our patients with the best possible aesthetic results.

  13. Effect of presilanization filler decontamination on aesthetics and degradation resistance of resin composites.

    Science.gov (United States)

    Yoshida, Yasuhiro; Shirai, Kenichi; Shintani, Hideaki; Okazaki, Masayuki; Suzuki, Kazuomi; Van Meerbeek, Bart

    2002-12-01

    Filler-matrix coupling determines, to a large extent, the mechanical strength and clinical longevity of dental composites. The aim of this study was to examine how far a methodology to decontaminate filler prior to silanization may improve aesthetic performance in addition to physico-mechanical properties such as degradation resistance. It was reported that filler particles are surrounded and wrapped by a film that consists of multiple layers of silane molecules. X-ray photoelectron spectroscopy, however, revealed that silanization of filler particles largely depended upon siloxane bridge (Si-O-Si) formation between the silica surface and the silane molecule rather than on intermolecular bonding between adjacent silane molecules. In this study, we showed that filler decontamination resulted in a higher translucency, thereby providing a better aesthetic potential. In addition, experimental composites produced following presilanization decontamination of filler revealed a higher Vickers hardness value and a diametral tensile strength that was resistant to degradation by thermo-cycling.

  14. Influence of Erosion Phenomenon on Flow Behavior of Liquid Al-Si Filler Between Brazed Components

    Science.gov (United States)

    Izumi, Takahiro; Ueda, Toshiki

    Automotive heat exchangers are predominantly composed of plates, tubes and fins. Each component is brazed by using Al-Si filler. In the plate/tube/fin brazed-structures, the flow of the liquid filler between the components affects the fillet size at each joint. In this study, the influence of the erosion phenomenon, i.e., silicon diffusion from the braze cladding into the core alloy, in the tube on the flow behavior of the liquid filler flowing on the tube from the plate to the fin has been investigated. As a result, the area of the liquid filler not flowing but existing around α phases on the tube during brazing, which is defined as filler flow channel, can change depending on the erosion degree. The flow ability of the liquid filler flowing from the plate to the fin increases as the area increases.

  15. Effect of filler type and polishing on the discoloration of composite resin artificial teeth.

    Science.gov (United States)

    Imamura, Soichiro; Takahashi, Hidekazu; Hayakawa, Iwao; Loyaga-Rendon, Paola G; Minakuchi, Shunsuke

    2008-11-01

    In this study, the effects of filler type and polishing on the discoloration of composite resin artificial teeth were examined. Four types of experimental resins were prepared: one was a matrix resin, while the others were composite resins containing three different types of fillers (nano-sized silica filler with or without silanization, and prepolymerized filler). Specimens were immersed in distilled water, coffee, red wine, or curry. Color change after immersion was measured using a colorimeter. Color difference values (delta E) and changes in translucency parameter (delta TP) were statistically analyzed using three-way ANOVA and Tukey's comparison. On the influence of the polishing factor, statistically significant differences were neither observed in delta E nor delta TP between polished and non-polished tooth surfaces. On the contrary, the influences of filler type and discoloration medium, and their interaction thereof, were significant. With unsilanized filler, the delta E value of composite resin artificial teeth was significantly increased.

  16. EFFECT OF FILLER LOADING ON PHYSICAL AND FLEXURAL PROPERTIES OF RAPESEED STEM/PP COMPOSITES

    Directory of Open Access Journals (Sweden)

    Seyed Majid Zabihzadeh

    2011-03-01

    Full Text Available The objective of the study is to develop a new filler for the production of natural filler thermoplastic composites using the waste rapeseed stalks. The long-term water absorption and thickness swelling behaviors and flexural properties of rapeseed filled polypropylene (PP composites were investigated. Three different contents of filler were tested: 30, 45, and 60 wt%. Results of long-term hygroscopic tests indicated that by the increase in filler content from 30% to 60%, water diffusion absorption and thickness swelling rate parameter increased. A swelling model developed by Shi and Gardner can be used to quantify the swelling rate. The increasing of filler content reduced the flexural strength of the rapeseed/PP composites significantly. In contrast to the flexural strength, the flexural modulus improved with increasing the filler content. The flexural properties of these composites were decreased after the water uptake, due to the effect of the water molecules.

  17. Brazing diamond grits onto a steel substrate using copper alloys as the filler metals

    Science.gov (United States)

    Chen, S.-M.; Lin, S.-T.

    1996-12-01

    Surface-set diamond tools were fabricated by an active metal brazing process, using bronze (Cu-8.9Sn) powder and 316L stainless steel powder mixed to various ratios as the braze filler metals. The diamond grits were brazed onto a steel substrate at 1050 °C for 30 min in a dry hydrogen atmosphere. After brazing practice, an intermediate layer rich in chromium formed between the braze filler metal and diamond. A braze filler metal composed of 70 wt % bronze powder and 30 wt % stainless steel powder was found to be optimum in that the diamond grits were strongly impregnated in the filler metal by both mechanical and chemical types of holding. The diamond tools thus fabricated performed better than conventional nickel-plated diamond tools. In service, the braze filler metal wore at almost the same rate as the diamond grits, and no pullout of diamond grits or peeling of the filler metal layer took place.

  18. Skin Necrosis with Oculomotor Nerve Palsy Due to a Hyaluronic Acid Filler Injection

    Directory of Open Access Journals (Sweden)

    Jae Il Lee

    2017-07-01

    Full Text Available Performing rhinoplasty using filler injections, which improve facial wrinkles or soft tissues, is relatively inexpensive. However, intravascular filler injections can cause severe complications, such as skin necrosis and visual loss. We describe a case of blepharoptosis and skin necrosis caused by augmentation rhinoplasty and we discuss the patient’s clinical progress. We describe the case of a 25-year-old female patient who experienced severe pain, blepharoptosis, and decreased visual acuity immediately after receiving a filler injection. Our case suggests that surgeons should be aware of nasal vascularity before performing an operation, and that they should avoid injecting fillers at a high pressure and/or in excessive amounts. Additionally, filler injections should be stopped if the patient complains of severe pain, and appropriate measures should be taken to prevent complications caused by intravascular filler injections.

  19. Brazing of copper to stainless steel with a low-silver-content brazing filler metal

    Science.gov (United States)

    Fukikoshi, Tatsuya; Watanabe, Yūki; Miyazawa, Yasuyuki; Kanasaki, Fumio

    2014-08-01

    The brazing of copper to stainless steel (SUS304 JIS) was performed using a low- silver-content brazing filler metal, Ag-50Cu, under an Ar gas atmosphere with a conventional furnace, owing to the potential economic benefits of using low-silver-content filler metals. The brazeability of the low-silver-content brazing filler metal to copper and SUS304 was investigated. A good joint was obtained, and a drastic dissolution reaction occurred at the copper side. Molten BAg8 penetrated along the crystal grain boundary of the copper base metal when BAg8 was used as the filler metal. This was caused by the dissolution of Ni from the stainless steel into the molten filler metal. Ag-50Cu, which was investigated in this work, can be used instead of BAg8 filler metal.

  20. Void measurement using high-resolution gamma-ray computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Bieberle, Andre, E-mail: a.bieberle@hzdr.de [Institute of Safety Research, Helmholz-Zentrum Dresden-Rossendorf, Bautzner Landstrasse 400, 01328 Dresden (Germany); Hoppe, Dietrich; Schleicher, Eckhard; Hampel, Uwe [Institute of Safety Research, Helmholz-Zentrum Dresden-Rossendorf, Bautzner Landstrasse 400, 01328 Dresden (Germany)

    2011-06-15

    Highlights: > We present a CT system determining void distributions in thermo hydraulic facilities. > The system has been carefully designed for harsh operating conditions. > To increase measurement accuracy a scattered correction algorithm was developed. > First results of laboratory measurements on a bundle mock-up are presented. - Abstract: We present a high-resolution gamma-ray computed tomography (CT) measurement system for the determination of cross-sectional time-averaged void distributions in thermo hydraulic facilities. The system has been carefully designed for harsh operating conditions, such as varying temperature fields and strong magnetic fields, typically produced by thermal hydraulic test loops with direct electric bundle heating. Measurements are non invasive, thus the two-phase flow in the test section is not influenced. The gamma-ray CT system consists of a collimated {sup 137}Cs isotopic source, a gamma radiation detector arc including 320 single elements, a pulse processing unit and a thermal stabilisation unit. The spatial resolution of the CT system is about 2 mm in plane. Recently, the thermal design of the detector arc is improved to secure maintenance of constant temperature of thermally sensitive components under changing environmental conditions. This turned out to be a key issue for achieving accurate quantitative measurements. First results of laboratory measurements on a bundle mock-up with this improved system are presented.

  1. Lithium ion conducting PVA:PVdF polymer electrolytes doped with nano SiO2 and TiO2 filler

    Science.gov (United States)

    Hema, M.; Tamilselvi, P.

    2016-09-01

    The effect of nano SiO2 and TiO2 fillers on the thermal, mechanical and electrochemical properties of PVA:PVdF:LiCF3SO3 have been investigated by three optimized systems of SPE (80PVA:20PVdF:15LiCF3SO3), CPE-I (SPE:8SiO2) and CPE-II (SPE:4TiO2). From the TGA curve least weight loss has been observed for CPE-II indicating high thermal stability compared to other systems. Stress-strain curve of the prepared samples confirm the enhancement of tensile strength in CPE-II compared to CPE-I and SPE. Conductivity studies show that addition of TiO2 filler slightly enhances ionic conductivity 3.7×10-3 S cm-1 compared to filler free system at 303 K. Dielectric plots have been analyzed and CPE-II possesses higher dielectric constant compared to CPE-I and filler free system. Temperature dependence of modulus plots has been studied for highest conductivity possessing sample. Wider electrochemical stability has been obtained for nano-composite polymer electrolytes. The results conclude that the prepared CPE-II shows the best performance and it will be well suited for lithium ion batteries.

  2. 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.

  3. Use of hyaluronic acid fillers for the treatment of the aging face

    OpenAIRE

    Michael H Gold

    2007-01-01

    Michael H GoldGold Skin Care Center, Tennessee Clinical Research Center, Nashville, TN, USA; Department of Medicine, Vanderbilt University Medical School,Vanderbilt University Nursing School, Nashville, TN, USA; Huashan Hospital, Fudan University, Shanghai, ChinaAbstract: Hyaluronic acid fillers have become popular soft tissue filler augmentation agents over the past several years. They have helped revolutionize the filler market with a number of new products available for use for our patient...

  4. Novel high chromium containing braze filler metals for heat exchanger applications

    Energy Technology Data Exchange (ETDEWEB)

    Rangaswamy, S.; Fortuna, D. [Sulzer Metco, Troy (United States)

    2007-07-01

    A new family of boron-free, high chromium containing braze filler metal compositions were developed (Amdry 105, Amdry 108, Amdry 805). Filler metal properties including metallurgical phases, melting range, flow, corrosion resistance and high temperature oxidation resistance are reported. Additionally, the technical and economical advantages of using these new filler metals in fabricating flat plate type of heat exchangers and metallic catalytic converters is discussed. (orig.)

  5. Characteristics of The Fillers Used for Realizing the Asphalt Mixtures in Romania

    Directory of Open Access Journals (Sweden)

    Irina-Mihaela Dămiean

    2005-01-01

    Full Text Available This paper presents the lab results for four types of filler used in producing the asphalt mixture in Romania, as well as other physical-chemical characteristics of a new type of filler, derivate of the grinding of the bituminous shists through a ball mill/crusher. Knowing these physical-chemical characteristics is crucial for asphalt mixtures due to the complex purpose of the filler.

  6. Increasing the wear resistance of ultra-high molecular weight polyethylene by adding solid lubricating fillers

    Energy Technology Data Exchange (ETDEWEB)

    Panin, S. V., E-mail: svp@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055, Russia and National Research Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation); Kornienko, L. A.; Poltaranin, M. A.; Ivanova, L. R. [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); Suan, T. Nguen [National Research Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation)

    2014-11-14

    In order to compare effectiveness of adding solid lubricating fillers for polymeric composites based on ultra-high molecular weight polyethylene (UHMWPE) with graphite, molybdenum disulfide and polytetrafluoroethylene, their tribotechnical characteristics under dry friction, boundary lubrication and abrasive wearing were investigated. The optimal weight fractions of fillers in terms of improving wear resistance have been determined. The supramolecular structure and topography of wear track surfaces of UHMWPE-based composites with different content of fillers have been studied.

  7. Effects of Rare Earths on Properties of Ti-Zr-Cu-Ni Base Brazing Filler Alloys

    Institute of Scientific and Technical Information of China (English)

    Ma Tianjun; Kang Hui; Wu Yongqin; Qu Ping

    2004-01-01

    The effects of the addition of rare earths on the properties of Ti-Zr-Cu-Ni base brazing filler alloys and the mechanical microstructure and properties were studied for the brazed-joints in the vacuum brazing of TC4 by comparing synthetical properties of two kinds of filler metals.The results indicate that the filler metals added with rare earths have lower melting point, better wettability and higher mechanical properties in the brazing joints.

  8. Mechanical Stress Effects on Electromigration Voiding in a Meandering Test Stripe

    Science.gov (United States)

    Lowry, L. E.; Tai, B. H.; Mattila, J.; Walsh, L. H.

    1993-01-01

    Earlier experimental findings concluded that electromigratin voids in these meandering stripe test structures were not randomly distributed and that void nucleation frequenly occurred sub-surface at the metal/thermal oxide interface.

  9. 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 vesico...

  10. Effects of fillers on the properties of liquid silicone rubbers (LSRs)

    DEFF Research Database (Denmark)

    Yu, Liyun; Vudayagiri, Sindhu; Zakaria, Shamsul Bin

    fillers. In this study commercially available fillers, such as fumed silica (SiO2), titanium dioxide (TiO2), barium titanate (BaTiO3), copper calcium titanate (CaCu3Ti4O12, CCTO), multi-walled carbon nanotubes (MWCNTs) were added into the LSRs and we examined how the properties of the networks were...... these additives, the use of multiple titanium dioxides as filler potentially suits to special applications. In the present study, a series of TiO2 fillers were blended into LSRs, such as hydrophilic/ hydrophobic, micro/ nano scale, anatase/ rutile crystal, sphere/ core-shell structure. The results indicate...

  11. Suspect filler similarity in eyewitness lineups: a literature review and a novel methodology.

    Science.gov (United States)

    Fitzgerald, Ryan J; Oriet, Chris; Price, Heather L

    2015-02-01

    Eyewitness lineups typically contain a suspect (guilty or innocent) and fillers (known innocents). The degree to which fillers should resemble the suspect is a complex issue that has yet to be resolved. Previously, researchers have voiced concern that eyewitnesses would be unable to identify their target from a lineup containing highly similar fillers; however, our literature review suggests highly similar fillers have only rarely been shown to have this effect. To further examine the effect of highly similar fillers on lineup responses, we used morphing software to create fillers of moderately high and very high similarity to the suspect. When the culprit was in the lineup, a higher correct identification rate was observed in moderately high similarity lineups than in very high similarity lineups. When the culprit was absent, similarity did not yield a significant effect on innocent suspect misidentification rates. However, the correct rejection rate in the moderately high similarity lineup was 20% higher than in the very high similarity lineup. When choosing rates were controlled by calculating identification probabilities for only those who made a selection from the lineup, culprit identification rates as well as innocent suspect misidentification rates were significantly higher in the moderately high similarity lineup than in the very high similarity lineup. Thus, very high similarity fillers yielded costs and benefits. Although our research suggests that selecting the most similar fillers available may adversely affect correct identification rates, we recommend additional research using fillers obtained from police databases to corroborate our findings.

  12. The Microstructural Evolution of Vacuum Brazed 1Cr18Ni9Ti Using Various Filler Metals

    Directory of Open Access Journals (Sweden)

    Yunxia Chen

    2017-04-01

    Full Text Available The microstructures and weldability of a brazed joint of 1Cr18Ni9Ti austenitic stainless steel with BNi-2, BNi82CrSiBFe and BMn50NiCuCrCo filler metals in vacuum were investigated. It can be observed that an interdiffusion region existed between the filler metal and the base metal for the brazed joint of Ni-based filler metals. The width of the interdiffusion region was about 10 μm, and the microstructure of the brazed joint of BNi-2 filler metal was dense and free of obvious defects. In the case of the brazed joint of BMn50NiCuCrCo filler metal, there were pits, pores and crack defects in the brazing joint due to insufficient wettability of the filler metal. Crack defects can also be observed in the brazed joint of BNi82CrSiBFe filler metal. Compared with BMn50NiCuCrCo and BNi82CrSiBFe filler metals, BNi-2 filler metal is the best material for 1Cr18Ni9Ti austenitic stainless steel vacuum brazing because of its distinct weldability.

  13. Improvement of Scratch and Wear Resistance of Polymers by Fillers Including Nanofillers

    Directory of Open Access Journals (Sweden)

    Witold Brostow

    2017-03-01

    Full Text Available Polymers have lower resistance to scratching and wear than metals. Liquid lubricants work well for metals but not for polymers nor for polymer-based composites (PBCs. We review approaches for improvement of tribological properties of polymers based on inclusion of fillers. The fillers can be metallic or ceramic—with obvious consequences for electrical resistivity of the composites. Distinctions between effectiveness of micro- versus nano-particles are analyzed. For example, aluminum nanoparticles as filler are more effective for property improvement than microparticles at the same overall volumetric concentration. Prevention of local agglomeration of filler particles is discussed along with a technique to verify the prevention.

  14. Improvement of Scratch and Wear Resistance of Polymers by Fillers Including Nanofillers.

    Science.gov (United States)

    Brostow, Witold; Lobland, Haley E Hagg; Hnatchuk, Nathalie; Perez, Jose M

    2017-03-16

    Polymers have lower resistance to scratching and wear than metals. Liquid lubricants work well for metals but not for polymers nor for polymer-based composites (PBCs). We review approaches for improvement of tribological properties of polymers based on inclusion of fillers. The fillers can be metallic or ceramic-with obvious consequences for electrical resistivity of the composites. Distinctions between effectiveness of micro- versus nano-particles are analyzed. For example, aluminum nanoparticles as filler are more effective for property improvement than microparticles at the same overall volumetric concentration. Prevention of local agglomeration of filler particles is discussed along with a technique to verify the prevention.

  15. Effects of beam configurations on wire melting and transfer behaviors in dual beam laser welding with filler wire

    Science.gov (United States)

    Ma, Guolong; Li, Liqun; Chen, Yanbin

    2017-06-01

    Butt joints of 2 mm thick stainless steel with 0.5 mm gap were fabricated by dual beam laser welding with filler wire technique. The wire melting and transfer behaviors with different beam configurations were investigated detailedly in a stable liquid bridge mode and an unstable droplet mode. A high speed video system assisted by a high pulse diode laser as an illumination source was utilized to record the process in real time. The difference of welding stability between single and dual beam laser welding with filler wire was also compartively studied. In liquid bridge transfer mode, the results indicated that the transfer process and welding stability were disturbed in the form of "broken-reformed" liquid bridge in tandem configuration, while improved by stabilizing the molten pool dynamics with a proper fluid pattern in side-by-side configuration, compared to sigle beam laser welding with filler wire. The droplet transfer period and critical radius were studied in droplet transfer mode. The transfer stability of side-by-side configuration with the minium transfer period and critical droplet size was better than the other two configurations. This was attributed to that the action direction and good stability of the resultant force which were beneficial to transfer process in this case. The side-by-side configuration showed obvious superiority on improving welding stability in both transfer modes. An acceptable weld bead was successfully generated even in undesirable droplet transfer mode under the present conditions.

  16. Histology of a novel injectable filler (polymethylmethacrylate and cross-linked dextran in hydroxypropyl methylcellulose) in a rat model.

    Science.gov (United States)

    Lee, Young Bok; Park, Sae Mi; Song, Eun Jong; Park, Jun-Gyu; Cho, Kyoung-Oh; Kim, Jin Wou; Yu, Dong Soo

    2014-08-01

    A novel injectable filler of polymethylmethacrylate (PMMA) and cross-linked dextran in hydroxypropyl methylcellulose was introduced in the commercial filler market. For soft tissue augmentation, safety and biocompatibility should be evaluated and the stability at the implantation site should be assessed using histologic evaluation. In order to evaluate the biocompatibility of the novel soft tissue filler, PMMA and cross-linked dextran in hydroxypropyl methylcellulose was subdermally injected into the skin of Sprague-Dawley Rats. Histologic evaluation was performed at 13 weeks and 12 months after the injection. Inflammatory cell infiltration, neovascularization, and fibrosis were scored according to defined grading systems. The mean score of the histologic evaluation was 5.7 and 3.9 at 13 weeks and 12 months, respectively. At 12 months after injection, the PMMA and cross-linked dextran in hydroxypropyl methylcellulose appeared to be kept in place through fine fibrous capsules. The mixture of PMMA and cross-linked dextran in hydroxypropyl methylcellulose can be safely applied for soft tissue augmentation with longevity of greater than 12 months.

  17. In vitro investigation of coupling-agent-free dental restorative composite based on nano-porous alumina fillers.

    Science.gov (United States)

    Thorat, Sanjay B; Diaspro, Alberto; Salerno, Marco

    2014-03-01

    The study aims at demonstrating the feasibility of a novel type of coupling-agent-free resin composite based on nano-porous fillers. The fillers were obtained by ball-milling anodic alumina membranes. Composites were prepared with standard resin at maximum loading of 50% by weight. The resin matrix penetration into the pores was verified visually by scanning electron microscopy and mechanically by atomic force microscopy in force modulation mode. The dynamic flexural modulus at 1Hz was measured by dynamic mechanical analysis. Silver nanoparticles were also synthesized in the pores and their release was investigated with inductive coupled plasma optical emission spectrometry. A storage modulus of 5GPa was measured, similar to the ∼6GPa ones of two coupling-agent-based dental restorative composites used for comparison, which is a promising starting point, additionally showing better one-year equivalent ageing as compared to both commercial materials. Loading the pores with silver nanoparticles was demonstrated as well as their subsequent release in a model system. The alumina micro-particles with interconnected nano-pores allow mechanical interlocking between fillers and matrix without the need for chemical bonding. This material is also promising for being made bio-active, after pore filling with different agents. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Acceleration of percolation for cementitious sensors using conductive paint filler

    Science.gov (United States)

    Pinto, Irvin Jude Joseph

    Structural health monitoring has emerged as an important branch of civil engineering in recent times, with the need to automatically monitor structural performance over time to ensure structural integrity. More recently, the advent of smart sensing materials has given this field a major boost. Research has shown that smart sensing materials fabricated with conductive filler at a concentration close to the percolation threshold results in high sensitivity to strain due to the piezoresistive effect. Of particular interest to this research are cementitious sensors fabricated using carbon black fillers. Carbon black is considered because of its widespread availability and low cost over other conductive fillers such as carbon nanotubes and carbon nanofibers. A challenge in the fabrication of these sensors is that cementitious materials require a significant amount of carbon black to percolate, resulting in a loss in mechanical properties. This research investigates a new method to accelerate percolation of the materials, enabling cementitious sensors with fewer carbon black particles. A carbon black-based conductive paint that allows earlier percolation by facilitating conducting networks in cementitious sensors is used. The conductive paint consists of a block copolymer, SEBS (styrene-co-ethylene-co-butylene-co-styrene), filled with carbon black particles. The percolation thresholds of sensors fabricated both with and without conductive paint are, as well as their strain sensing characteristics and compressive strength. The study found that SEBS could successfully reduce the percolation threshold by 42%, and that samples with SEBS showed better electrical responses in dynamic conditions. Despite showing lower compressive strength, cementitious sensors fabricated with this novel conductive paint show promise for real time health monitoring applications.

  19. 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...

  20. 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

    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....

  1. 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...

  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...

  3. 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...

  4. 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

    2011-11-01

    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. 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. 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. 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. Copyright © 2011 Wiley Periodicals, Inc.

  5. Soft tissue augmentation - Use of hyaluronic acid as dermal filler

    Directory of Open Access Journals (Sweden)

    Vedamurthy Maya

    2004-01-01

    Full Text Available Soft tissue augmentation has revolutionized the treatment of the aging face. It is a technique in which a substance is injected under the skin. The concept of utilizing materials for soft tissue augmentation actually began around 1950 with the use of fluid silicone. Today we have a large armamentarium of implant materials to delay the tell tale signs of aging. Filling has replaced conventional surgery in facial rejuvenation. In this article, the emphasis will be on hyaluronic acid as this substance is easily available in India and ranks among the most widely used dermal fillers.

  6. Mechanical and Morphological Properties of Nano Filler Polyester Composites

    OpenAIRE

    Bonnia Noor Najmi; Redzuan Aein Afina; Shuhaimeen Nurul Shakirah

    2016-01-01

    This research is focusing on mechanical and morphological properties of unsaturated polyester (UP) reinforced with two different types of filler which is nano size clay Cloisite 30B (C30B) and Carbon Black (CB). Samples were fabricated via hand lay-up and open molding technique. Percentages of Cloisite 30B & Carbon Black (CB) used vary from 0, 2, 4, 6, 8 and 10 wt%. The mechanical properties were evaluated by impact, flexural and hardness testing. Result shows that the mechanical strength of ...

  7. Epoxy composites based on inexpensive tire waste filler

    Science.gov (United States)

    Ahmetli, Gulnare; Gungor, Ahmet; Kocaman, Suheyla

    2014-05-01

    Tire waste (TW) was recycled as raw material for the preparation of DGEBA-type epoxy composite materials. The effects of filler amount and epoxy type on the mechanical properties of the composites were investigated. Tensile strength and Young's modulus of the composites with NPEL were generally higher than composites with NPEF. The appropriate mass level for TW in both type composites was found to be 20 wt%. The equilibrium water sorption of NPEL/TW and NPEF/TW composites for 14-day immersion was determined as 0.10 % and 0.21 %, respectively. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used for characterization of the composites.

  8. Numerical simulation of filler metal droplets spreading in laser brazing

    Science.gov (United States)

    Chen, Yanbin; Feng, Xiaosong; Li, Liqun

    2007-11-01

    A finite element model was constructed using a commercial software Fidap to analyze the Cu-base filler metal droplet spreading process in laser brazing, in which the temperature distribution, droplet geometry, and fluid flow velocity were calculated. Marangoni and buoyancy convection and gravity force were considered, and the effects of laser power and spot size on the spreading process were evaluated. Special attention was focused on the free surface of the droplet, which determines the profile of the brazing spot. The simulated results indicate that surface tension is the dominant flow driving force and laser spot size determines the droplet spreading domain.

  9. Phosphogypsum Utilization Part III: as Adhesive Filler and Composite Materials

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The aim of this work is to make use of phosphogypsum (PG) waste material, which is produced in phosphoric acid and phosphate fertilizer manufactures. A number of wood adhesive formulations based on polyvinyl acetate (PVAc) polymer and phosphogypsum as a filler have been prepared, using different percentages of phusphogypsum, ranging between 5~20 wt pct. The prepared formulations wore tested for adhesion strength and compared with both natural and pure gypsum fillers. The results indicate that PG improves the adhesion strenth when 5 wt pct added, and that may be due to filling the porous surface of wood with the fine particles of PG, as well as coating the particles of the filler (PG) with PVAc units. Also, a number of formulations based on urea-formaldehyde polymer have been prepared using phosphogypsum as an active filler in the ratio of 40~75 wt pct to prepare composite materials used for some decoration purposes and construction. Mechanical, physical, and thermal properties of these formulations were studied. Also, the activation energy was calculated. The results indicate that PG without acid hardener can be used for preparation of composite materials based on urea-formaldehyde between 40~63.64 wt pct for construction purposes in the humid atmosphere, while between 63.64~75 wt pct for decoration purposes. The improvement of the physical, mechanical and thermal properties of the composite material may be attributed to the simultaneous hydration hardening action of phosphogypsum and the presence of 0.8% P2O5. These effects act as an active hardener for urea-formaldehyde resin and accelerate the cross-linking and network formation reinforced by the fine dusty inorganic particles of PG. The advantage of this method is to prepare composite material gypsum-urea-formaldehyde, which achieves the utilization of large amount of PG, reducing the price of the main product phosphate, minimizing the pollution and producing new materials which possess high thermal

  10. Numerical simulation of filler metal droplets spreading in laser brazing

    Institute of Scientific and Technical Information of China (English)

    Yanbin Chen; Xiaosong Feng; Liqun Li

    2007-01-01

    A finite element model was constructed using a commercial software Fidap to analyze the Cu-base filler metal droplet spreading process in laser brazing, in which the temperature distribution, droplet geometry,and fluid flow velocity were calculated. Marangoni and buoyancy convection and gravity force were considered, and the effects of laser power and spot size on the spreading process were evaluated. Special attention was focused on the free surface of the droplet, which determines the profile of the brazing spot.The simulated results indicate that surface tension is the dominant flow driving force and laser spot size determines the droplet spreading domain.

  11. Constraining CMB-consistent primordial voids with cluster evolution

    CERN Document Server

    Mathis, H; Griffiths, L M; Kunz, M

    2004-01-01

    Using cosmological simulations, we make predictions for the distribution of clusters in a plausible non-gaussian model where primordial voids nucleated during inflation act together with scale-invariant adiabatic gaussian fluctuations as seeds for the formation of large-scale structure. This model agrees with most recent observations of the anisotropies of the cosmic microwave background (CMB) and can account for the excess of power measured on cluster scales by the Cosmic Background Imager (CBI), the large empty regions apparent in nearby galaxy redshift surveys and the number of giant arcs measured in deep cluster lensing surveys. We show that the z=0 cluster mass function differs from predictions for a standard LCDM cosmology with the same sigma_8. Moreover, as massive clusters also form much earlier in the "void" scenario, we show that integrated number counts of SZ sources and simple statistics of strong lensing can easily falsify this model.

  12. On the void explanation of the Cold Spot

    Science.gov (United States)

    Marcos-Caballero, A.; Fernández-Cobos, R.; Martínez-González, E.; Vielva, P.

    2016-07-01

    The integrated Sachs-Wolfe (ISW) contribution induced on the cosmic microwave background by the presence of a supervoid as the one detected by Szapudi et al. (2015) is reviewed in this letter in order to check whether it could explain the Cold Spot (CS) anomaly. Two different models, previously used for the same purpose, are considered to describe the matter density profile of the void: a top hat function and a compensated profile produced by a Gaussian potential. The analysis shows that, even enabling ellipticity changes or different values for the dark-energy equation of state parameter ω, the ISW contribution due to the presence of the void does not reproduce the properties of the CS.

  13. The ISW imprints of voids and superclusters on the CMB

    Science.gov (United States)

    Hotchkiss, S.; Nadathur, S.; Gottlöber, S.; Iliev, I. T.; Knebe, A.; Watson, W. A.; Yepes, G.

    2016-10-01

    We examine the stacked integrated Sachs-Wolfe (ISW) imprints on the CMB along the lines of sight of voids and superclusters in galaxy surveys, using the Jubilee ISW simulation and mock luminous red galaxy (LRG) catalogues. We show that the expected signal in the concordance \\Lam CDM model is much smaller than the primary anisotropies arising at the last scattering surface and therefore any currently claimed detections of such an imprint cannot be caused by the ISW effect in \\Lam CDM. We look for the existence of such a signal in the Planck CMB using a catalogue of voids and superclusters from the Sloan Digital Sky Survey (SDSS), but find a result completely consistent with \\Lam CDM - i.e., a null detection.

  14. Study on voids of epoxy matrix composites sandwich structure parts

    Science.gov (United States)

    He, Simin; Wen, Youyi; Yu, Wenjun; Liu, Hong; Yue, Cheng; Bao, Jing

    2017-03-01

    Void is the most common tiny defect of composite materials. Porosity is closely related to composite structure property. The voids forming behaviour in the composites sandwich structural parts with the carbon fiber reinforced epoxy resin skins was researched by adjusting the manufacturing process parameters. The composites laminate with different porosities were prepared with the different process parameter. The ultrasonic non-destructive measurement method for the porosity was developed and verified through microscopic examination. The analysis results show that compaction pressure during the manufacturing process had influence on the porosity in the laminate area. Increasing the compaction pressure and compaction time will reduce the porosity of the laminates. The bond-line between honeycomb core and carbon fiber reinforced epoxy resin skins were also analyzed through microscopic examination. The mechanical properties of sandwich structure composites were studied. The optimization process parameters and porosity ultrasonic measurement method for composites sandwich structure have been applied to the production of the composite parts.

  15. Analytical Description of Voids in Majumdar-Papapetrou Spacetimes

    CERN Document Server

    Varela, V

    1999-01-01

    We discuss new Majumdar-Papapetrou solutions for the 3+1 Einstein-Maxwell equations, with charged dust acting as the external source of the fields. The solutions satisfy non-linear potential equations which are related to well-known wave equations of 1+1 soliton physics. Although the matter distributions are not localised, they present central structures which may be identified with voids.

  16. The Persistent Percolation of Single-Stream Voids

    CERN Document Server

    Falck, Bridget

    2014-01-01

    We study the nature of voids defined as single-stream regions that have not undergone shell-crossing. We use ORIGAMI to determine the cosmic web morphology of each dark matter particle in a suite of cosmological $N$-body simulations, which explicitly calculates whether a particle has crossed paths with others along multiple sets of axes and does not depend on a parameter or smoothing scale. The theoretical picture of voids is that of expanding underdensities with borders defined by shell-crossing. We find instead that locally underdense single-stream regions are not bounded on all sides by multi-stream regions, thus they percolate, filling the simulation volume; we show that the set of multi-stream particles also percolates. This percolation persists to high resolution, where the mass fraction of single-stream voids is low, because the volume fraction remains high; we speculate on the fraction of collapsed mass in the continuum limit of infinite resolution. By introducing a volume threshold parameter to defin...

  17. 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

  18. 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.

  19. Tomography of integrated circuit interconnect with an electromigration void

    Energy Technology Data Exchange (ETDEWEB)

    Levine, Zachary H. [National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8410 (United States); Rensselaer Polytechnic Institute, Troy, New York 12180-3590 (United States); Kalukin, Andrew R. [National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8410 (United States); Kuhn, Markus [Intel Corporation RA1-329, 5200 Northeast Elam Young Parkway, Hillsboro, Oregon 74124 (United States); Frigo, Sean P. [Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); McNulty, Ian [Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); Retsch, Cornelia C. [Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); Wang, Yuxin [Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); Arp, Uwe [National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8410 (United States); Lucatorto, Thomas B. [National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8410 (United States); Ravel, Bruce D. [National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8410 (United States)] (and others)

    2000-05-01

    An integrated circuit interconnect was subject to accelerated-life test conditions to induce an electromigration void. The silicon substrate was removed, leaving only the interconnect test structure encased in silica. We imaged the sample with 1750 eV photons using the 2-ID-B scanning transmission x-ray microscope at the Advanced Photon Source, a third-generation synchrotron facility. Fourteen views through the sample were obtained over a 170 degree sign range of angles (with a 40 degree sign gap) about a single rotation axis. Two sampled regions were selected for three-dimensional reconstruction: one of the ragged end of a wire depleted by the void, the other of the adjacent interlevel connection (or ''via''). We applied two reconstruction techniques: the simultaneous iterative reconstruction technique and a Bayesian reconstruction technique, the generalized Gaussian Markov random field method. The stated uncertainties are total, with one standard deviation, which resolved the sample to 200{+-}70 and 140{+-}30 nm, respectively. The tungsten via is distinguished from the aluminum wire by higher absorption. Within the void, the aluminum is entirely depleted from under the tungsten via. The reconstructed data show the applicability of this technique to three-dimensional imaging of buried defects in submicrometer structures relevant to the microelectronics industry. (c) 2000 American Institute of Physics.

  20. On the Star Formation Properties of Void Galaxies

    CERN Document Server

    Moorman, Crystal M; White, Amanda; Vogeley, Michael S; Hoyle, Fiona; Giovanelli, Riccardo; Haynes, Martha P

    2016-01-01

    We measure the star formation properties of two large samples of galaxies from the SDSS in large-scale cosmic voids on time scales of 10 Myr and 100 Myr, using H$\\alpha$ emission line strengths and GALEX FUV fluxes, respectively. The first sample consists of 109,818 optically selected galaxies. We find that void galaxies in this sample have higher specific star formation rates (SSFRs; star formation rates per unit stellar mass) than similar stellar mass galaxies in denser regions. The second sample is a subset of the optically selected sample containing 8070 galaxies with reliable HI detections from ALFALFA. For the full HI detected sample, SSFRs do not vary systematically with large-scale environment. However, investigating only the HI detected dwarf galaxies reveals a trend towards higher SSFRs in voids. Furthermore, we estimate the star formation rate per unit HI mass (known as the star formation efficiency; SFE) of a galaxy, as a function of environment. For the overall HI detected population, we notice n...

  1. 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.

  2. VOID GROWTH AND CAVITATION IN NONLINEAR VISCOELASTIC SOLIDS

    Institute of Scientific and Technical Information of China (English)

    张赟; 黄筑平

    2003-01-01

    This paper discusses the growth of a pre-existing void in a nonlinear viscoelastic material subjected to remote hydrostatic tensions with different loading rates. The constitutive relation of this viscoelastic material is the one recently proposed by the present authors, which may be considered as a generalization of the non-Gaussian statistical theory in rubber elasticity. As the first order approximation, the above constitutive relation can be reduced to the "neo-Hookean" type viscoelastic one.Investigations of the influences of the material viscosity and the loading rate on the void growth, or on the cavitation are carried out. It is found that: (1) for generalized "inverse Langevin approximation"nonlinear viscoelastic materials, the cavitation limit does not exist, but there is a certain (remote)stress level at which the void will grow rapidly; (2) for generalized "Gaussian statistics" (neo-Hookean type) viscoelastic materials, the cavitation limit exists, and is an increasing function of the loading rate.The present discussions may be of importance in understanding the material failure process under high triaxial stress.

  3. Confirmation of sublunarean voids and thin layering in mare deposits

    Science.gov (United States)

    Robinson, M. S.; Ashley, J. W.; Boyd, A. K.; Wagner, R. V.; Speyerer, E. J.; Ray Hawke, B.; Hiesinger, H.; van der Bogert, C. H.

    2012-08-01

    Typical flow thicknesses of lunar mare basalts were not well constrained in the past, because as craters and rilles age, downslope movement of loose material tends to mix and bury stratigraphy, obscuring the three dimensional nature of the maria. New Lunar Reconnaissance Orbiter Camera high resolution images unambiguously reveal thicknesses of mare basalt layers exposed in impact craters, rilles, and steep-walled pits. Pits up to one hundred meters deep present relatively unmodified, near-vertical sections of mare in three cases, and many young impact craters also expose well preserved sections of mare. Oblique views of each pit and many of these craters reveal multiple layers, 3 to 14 m thick, indicating that eruptions typically produced a series of ˜10 m thick flows (or flow lobes) rather than flows many tens to hundreds of meters thick. Additionally, these images unambiguously show that the floors of two pits extend beneath the mare surfaces, thus revealing sublunarean voids of unknown lateral extent. We also document the occurrence of pits that may be expressions of collapse into subsurface voids in non-mare impact melt deposits. These voids are compelling targets for future human and robotic exploration, with potential as temporary shelters, habitations, or geologic museums.

  4. 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)

  5. Effect of nonlinear void reactivity on bifurcation characteristics of a lumped-parameter model of a BWR: A study relevant to RBMK

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Dinkar, E-mail: dinkar@iitk.ac.in [Nuclear Engineering and Technology Program, Indian Institute of Technology Kanpur, Kanpur 208 016 (India); Kalra, Manjeet Singh, E-mail: drmanjeet.singh@dituniversity.edu.in [DIT University, Dehradun 248 009 (India); Wahi, Pankaj, E-mail: wahi@iitk.ac.in [Department of Mechanical Engineering, Indian Institute of Technology Kanpur, Kanpur 208 016 (India)

    2017-04-15

    Highlights: • A simplified model with nonlinear void reactivity feedback is studied. • Method of multiple scales for nonlinear analysis and oscillation characteristics. • Second order void reactivity dominates in determining system dynamics. • Opposing signs of linear and quadratic void reactivity enhances global safety. - Abstract: In the present work, the effect of nonlinear void reactivity on the dynamics of a simplified lumped-parameter model for a boiling water reactor (BWR) is investigated. A mathematical model of five differential equations comprising of neutronics and thermal-hydraulics encompassing the nonlinearities associated with both the reactivity feedbacks and the heat transfer process has been used. To this end, we have considered parameters relevant to RBMK for which the void reactivity is known to be nonlinear. A nonlinear analysis of the model exploiting the method of multiple time scales (MMTS) predicts the occurrence of the two types of Hopf bifurcation, namely subcritical and supercritical, leading to the evolution of limit cycles for a range of parameters. Numerical simulations have been performed to verify the analytical results obtained by MMTS. The study shows that the nonlinear reactivity has a significant influence on the system dynamics. A parametric study with varying nominal reactor power and operating conditions in coolant channel has also been performed which shows the effect of change in concerned parameter on the boundary between regions of sub- and super-critical Hopf bifurcations in the space constituted by the two coefficients of reactivities viz. the void and the Doppler coefficient of reactivities. In particular, we find that introduction of a negative quadratic term in the void reactivity feedback significantly increases the supercritical region and dominates in determining the system dynamics.

  6. Orientation dependence of void growth at triple junction of grain boundaries in nanoscale tricrystal nickel film subjected to uniaxial tensile loading

    Science.gov (United States)

    Zhang, Yanqiu; Jiang, Shuyong; Zhu, Xiaoming; Sun, Dong

    2016-11-01

    Molecular dynamics simulation was performed in order to investigate the dependence of void growth on crystallographic orientation at the triple junction of grain boundaries in nanoscale tricrystal nickel film subjected to uniaxial tensile loading. The nucleation, the emission and the transmission of Shockley partial dislocations play a predominant role in the growth of void at the triple junction of grain boundaries. The orientation factors of various slip systems are calculated according to Schmid law. The slip systems activated in a grain of tricrystal nickel film basically conform to Schmid law which is completely suitable for a single crystal. The activated slip systems play an important role in plastic deformation of nanoscale tricrystal nickel film subjected to uniaxial tensile loading. The slip directions exhibit great difference among the activated slip systems such that the void is caused to be subjected to various stress conditions, which further leads to the difference in void growth among the tricrystal nickel films with different orientation distributions. It can be concluded that the grain orientation distribution has a significant influence on void growth at the triple junction of grain boundaries.

  7. 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

    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......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...

  8. Facial rejuvenation with fillers: The dual plane technique

    Directory of Open Access Journals (Sweden)

    Giovanni Salti

    2015-01-01

    Full Text Available Background: Facial aging is characterized by skin changes, sagging and volume loss. Volume is frequently addressed with reabsorbable fillers like hyaluronic acid gels. Materials and Methods: From an anatomical point of view, the deep and superficial fat compartments evolve differently with aging in a rather predictable manner. Volume can therefore be restored following a technique based on restoring first the deep volumes and there after the superficial volumes. We called this strategy "dual plane". A series of 147 consecutive patients have been treated with fillers using the dual plane technique in the last five years. Results: An average of 4.25 session per patient has been carried out for a total of 625 treatment sessions. The average total amount of products used has been 12 ml per patient with an average amount per session of 3.75 ml. We had few and limited adverse events with this technique. Conclusion: The dual plane technique is an injection technique based on anatomical logics. Different types of products can be used according to the plane of injection and their rheology in order to obtain a natural result and few side effects.

  9. Thermal Conductivity of Polymer/Nano-filler Blends

    Science.gov (United States)

    Ghose, Sayata; Watson, Kent A.; Delozier, Donovan M.; Working, Dennis C.; Connell, John W.; Smith, Joseph G.; Sun, Y. P.; Lin, Y.

    2006-01-01

    To improve the thermal conductivity of an ethylene vinyl acetate copolymer, Elvax 260 was compounded with three carbon based nano-fillers. Multiwalled carbon nanotubes (MWCNT), vapor grown carbon nanofibers (CNF) and expanded graphite (EG) were investigated. In an attempt to improve compatibility between the Elvax and nanofillers, MWCNTs and EGs were modified through non covalent and covalent attachment of alkyl groups. Ribbons were extruded to form samples in which the nanofillers were aligned, and samples were also fabricated by compression molding in which the nano-fillers were randomly oriented. The thermal properties were evaluated by DSC and TGA, and mechanical properties of the aligned samples were determined by tensile testing. The degree of dispersion and alignment of the nanoparticles were investigated using high-resolution scanning electron microscopy. Thermal conductivity measurements were performed using a Nanoflash technique. The thermal conductivity of the samples was measured in both the direction of alignment as well as perpendicular to that direction. The results of this study will be presented.

  10. Ionic conductivity enhancement of polymer electrolytes with ceramic nanowire fillers.

    Science.gov (United States)

    Liu, Wei; Liu, Nian; Sun, Jie; Hsu, Po-Chun; Li, Yuzhang; Lee, Hyun-Wook; Cui, Yi

    2015-04-08

    Solid-state electrolytes provide substantial improvements to safety and electrochemical stability in lithium-ion batteries when compared with conventional liquid electrolytes, which makes them a promising alternative technology for next-generation high-energy batteries. Currently, the low mobility of lithium ions in solid electrolytes limits their practical application. The ongoing research over the past few decades on dispersing of ceramic nanoparticles into polymer matrix has been proved effective to enhance ionic conductivity although it is challenging to form the efficiency networks of ionic conduction with nanoparticles. In this work, we first report that ceramic nanowire fillers can facilitate formation of such ionic conduction networks in polymer-based solid electrolyte to enhance its ionic conductivity by three orders of magnitude. Polyacrylonitrile-LiClO4 incorporated with 15 wt % Li0.33La0.557TiO3 nanowire composite electrolyte exhibits an unprecedented ionic conductivity of 2.4 × 10(-4) S cm(-1) at room temperature, which is attributed to the fast ion transport on the surfaces of ceramic nanowires acting as conductive network in the polymer matrix. In addition, the ceramic-nanowire filled composite polymer electrolyte shows an enlarged electrochemical stability window in comparison to the one without fillers. The discovery in the present work paves the way for the design of solid ion electrolytes with superior performance.

  11. Impedance characterization of epoxy composite containing conductive hybrid carbon fillers

    Science.gov (United States)

    Othman, Raja Nor; Tawil, Siti Nooraya; Zailan, Suhaila

    2017-08-01

    Epoxy composites containg carbon fillers are prepared in this work with an intention to characterise their electrical properties. The performance of electrical conductivity of epoxy composites is assessed by adding various loadings of conductive carbon fillers into the neat epoxy. First, Carbon Black (CB) was incorporated within epoxy matrix at several loadings. The increase in the specific conductivity of more than five orders of magnitude was observed between 3 wt. % and 4 wt.% CB loading, recorded at 10 kHz frequency. As such, the critical percolation loading, pc was recorded in between 3 wt.% and 4 wt.%. For the samples containing CB at loading 4 wt.% and above, the conductivity remains independent of the frequency, indicating a purely ohmic behaviour. It is also observed that the specific conductivity values can be altered by increasing the hardener stirring time up to 15 minutes, where the pc was successfully lowered down to < 3 wt. % It was further intended to study the hybrid effects by adding CNT to the composites. The conductivity data showed that the composite becomes frequency independent, even at 2 wt. % carbon loading (1 wt. % CB + 1 wt. % CNT), demonstrating the roles contributed by high aspect ratio conductive CNT in enhancing the formation of percolated path at much lower loading.

  12. Cross-sectional void fraction distribution measurements in a vertical annulus two-phase flow by high speed X-ray computed tomography and real-time neutron radiography techniques

    Energy Technology Data Exchange (ETDEWEB)

    Harvel, G.D. [McMaster Univ., Ontario (Canada)]|[Combustion and Heat Transfer Lab., Takasago (Japan); Hori, K.; Kawanishi, K. [Combustion and Heat Transfer Lab., Takasago (Japan)] [and others

    1995-09-01

    A Real-Time Neutron Radiography (RTNR) system and a high speed X-ray Computed tomography (X-CT) system are compared for measurement of two-phase flow. Each system is used to determine the flow regime, and the void fraction distribution in a vertical annulus flow channel. A standard optical video system is also used to observe the flow regime. The annulus flow channel is operated as a bubble column and measurements obtained for gas flow rates from 0.0 to 30.01/min. The flow regimes observed by all three measurement systems through image analysis shows that the two-dimensional void fraction distribution can be obtained. The X-CT system is shown to have a superior temporal resolution capable of resolving the void fraction distribution in an (r,{theta}) plane in 33.0 ms. Void fraction distribution for bubbly flow and slug flow is determined.

  13. Technical Note: Filler and superplasticizer usage on high strength concrete

    Directory of Open Access Journals (Sweden)

    Sümer, M.

    2007-08-01

    Full Text Available In this research, the effects of filler (rock-dust usage on high strength concrete have been investigated through lab experiments and some results have been obtained. The experiments involved three series of concrete with different cement proportions of 375 kg/m3, 400 kg/m3, and 425 kg/m3. For each series of concrete, three different groups of samples have been prepared, the first one being the reference concrete which contained 0% chemical admixture and 0% filler, the second one contained 1.5% chemical admixture and 0% filler and finally the last group contained 1.5% chemical admixture and 5% filler to the weight of cement used. The chemical admixture used was a type of Super plasticizer with a brand name of “DARACEM 190”, and the cement used was Ordinary Portland Cement of target compressive strength 42.5 N/mm2, obtained from Nuh Cement Plant. For each batch, Slump Tests and Unit Weight Tests were performed. For each stage and group, two 15 cm cubic samples have been tested for Compressive Strength after being cured in water at 20 ± 2 °C for ages of 3 days, 7 days, 28 and 60 days. The total number of samples was 72. As a result, filler usage was found to reduce the porosity of Concrete, increase the Unit Weight of Concrete, increase the need for water and improve the Compressive Strength Properties of Concrete.En el presente trabajo se estudia la influencia de la utilización de un “filler” (polvo mineral en el comportamiento del hormigón de altas prestaciones. Para ello, se realizan ensayos de laboratorio en los que se emplean tres series de hormigón, cada una con una dosificación de cemento distinta, de 375, 400 y 425 kg/m3. Se preparan tres grupos de probetas de cada serie, el primero o de referencia con 0% de aditivo químico y 0% de “filler”, el segundo con un 1,5% del aditivo químico y 0% de “filler” y el tercero con un 1,5% del aditivo químico y un 5% de “filler” en peso del cemento. Como aditivo se

  14. Effects of fillers on the properties of liquid silicone rubbers (LSRs)

    DEFF Research Database (Denmark)

    Yu, Liyun; Vudayagiri, Sindhu; Zakaria, Shamsul Bin

    low viscosities, which is favorable for loading of inorganic fillers [5]. In this study, commercially available fillers, such as fumed silica (SiO2), titanium dioxide (TiO2), barium titanate (BaTiO3), copper calcium titanate (CaCu3Ti4O12, CCTO), multi-walled carbon nanotubes (MWCNTs) were added...

  15. THE QUANTUM – MECHANICAL MODEL OF FORMING CONTACT AREAS IN COMPOSITE MATERIALS WITH SPHERICAL FILLER

    Directory of Open Access Journals (Sweden)

    E. V. Suhovaya

    2011-01-01

    Full Text Available The structure and properties of the composites having Fe-C-B-Р binders alloyed with molybdenum and strengthened by the W-C quickly-cooled filler were investigated in this work. The model based on quantum mechanics principles explaining the dependencies of contact interaction zones width on filler diameter was suggested.

  16. Perspectives for Titanium-Derived Fillers Usage on Denture Base Composite Construction: A Review Article

    Directory of Open Access Journals (Sweden)

    Nidal W. Elshereksi

    2014-01-01

    Full Text Available Poly(methyl methacrylate (PMMA is an extensively used material in dentistry because of its aesthetics, processability, and reparability. However, PMMA is still far from being ideal in fulfilling the mechanical requirements of prosthesis. PMMA-based denture base polymers exhibit low fracture resistance and radiopacity behavior. Efforts to improve the mechanical and radiopacity properties of denture base materials through inclusion of silica-based fillers are ongoing. Although silane-treated siliceous fillers are commonly used, they are not sufficiently strong. They also exhibit cracks, which either cut through the glass fillers or propagate around the filler particles. This defect occurs when the dental composites are placed in aqueous oral environment because of the hydrolytic degradation of silica-based fillers and silane-coupling agents. The clinical problem of using silanes in adhesion promotion is bond degradation over time in oral environment. In addition, silanes do not bond effectively to nonsilica-based dental restorative materials. This review presents titanium-derived fillers as alternatives to siliceous fillers. Titanate-coupling agents are found to be effective couplers in treating Ti-based fillers because of their chemical compatibility and relatively high stability in aqueous environment.

  17. Influence of Sn on Microstructure and Performance of Electric Vacuum Ag-Cu Filler Metal

    Directory of Open Access Journals (Sweden)

    SHI Lei

    2016-10-01

    Full Text Available Influence of Sn on microstructure, melting characteristic and brazing performance of electric vacuum Ag-Cu filler metal was studied by using scanning electronic microscope (SEM with energy disperse spectroscopy (EDS, differential scanning calorimetry (DSC and contrast tests. The results show that, while the addition of Sn is 4% (mass fraction,the same below, there is no brittle β-Cu phase in Ag60Cu filler metal,the effect on the processing performance is not obvious; with the increase of Sn content, the liquidus temperature of Ag60Cu filler metal decreases gradually, but the solidus temperature drops drastically,resulting in wider melting temperature range, and worse gap filling ability of filler metal. The Ag60Cu filler metal with Sn content of 4% has good spreading and metallurgical bonding abilities on copper plates, which are closer to that of BAg72Cu filler metal, and it can be processed into flake filler metal to replace the BAg72Cu flake filler metal to be used.

  18. Effect of Filler Composition on the Brazing of Alumina to Copper Using Ultrasonic Wave

    Institute of Scientific and Technical Information of China (English)

    Khalid M. HAFEZ; Masaaki NAKA

    2003-01-01

    An ultrasonic wave was applied during brazing of alumina to Cu. First alumina was metallized by applying ultrasonicwave in braze bath. Then the metallized alumina was brazed with Cu using the same filler alloy. The filler used wereZn-Al alloys and Zn-Sn A

  19. 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

    After solidification and cooling cast ingots contain voids due to improper feeding and volume shrinkage. Such voids are normally unwanted, so besides of forming the ingot to the desired shape, one of the purposes of the post processing of the ingot by hot forging is to close such voids by mechani......After solidification and cooling cast ingots contain voids due to improper feeding and volume shrinkage. Such voids are normally unwanted, so besides of forming the ingot to the desired shape, one of the purposes of the post processing of the ingot by hot forging is to close such voids...... and focuses on how the voids deform depending on their size and distribution in the ingot as well ashow the forging forces are applied....

  20. Effect of Temperature on the Void Growth in Pure Aluminium at High Strain-Rate Loading

    Institute of Scientific and Technical Information of China (English)

    QI Mei-Lan; HE Hong-Liang; YAN Shi-Lin

    2007-01-01

    @@ With the environment temperature varying from 273K to 773K, the dynamic process of void growth in pure aluminium at high strain-rate loading is calculated based on the dynamic growth equation of a void with internal pressure. The result shows that the effect of temperature on the growth of void should be emphasized. Because the initial pressure of void with gas will increase and the viscosity of materials will decrease with the rising of temperature, the growth of void is accelerated. Furthermore, material inertia restrains the growth of void evidently when the diameter exceeds 10μm. The effect of surface tension is very weak in the whole process of void growth.