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Sample records for maximum voided volume

  1. Evaluation of maximum voided volume in Korean children by use of a 48-h frequency volume chart.

    Science.gov (United States)

    Kim, Sun-Ouck; Kim, Kyung Do; Kim, Young Sig; Kim, Jun Mo; Moon, Du Geon; Park, Sungchan; Lee, Sang Don; Chung, Jae Min; Cho, Won Yeol

    2012-08-01

    Study Type - Diagnostic (validating cohort). Level of Evidence 2a. What's known on the subject? and What does the study add? The relationship between the maximum voided volume followed a linear curve. The formula presented, bladder capacity (mL) = 12 ×[age (years) + 11], is thought to be a reasonable one for Korean children. Korean children have a smaller bladder capacity than that reported in previous Western studies. • To develop practical guidelines for the prediction of normal bladder capacity in Korean children measured by a frequency volume chart (FVC), maximum voided volume (MVV) is an important factor in the diagnosis of children with abnormal voiding function. • In all, 298 children, aged 3-13 years, with no history of voiding disorders volunteered for the study. The MVV was determined in 219 subjects by use of a completely recorded FVC. • Linear regression analysis was used to define the exact relationship between age and bladder capacity. An approximate formula related age to bladder capacity as follows: bladder capacity (mL) = 12 ×[age (years) + 11]. • The relationship between the MVV measured by a FVC by age (3-13 years) of Korean children followed a linear curve. • When applied to normal voiding patterns, the formula presented appears to be a reasonable one for Korean children. © 2011 BJU INTERNATIONAL.

  2. It is time to abandon "expected bladder capacity." Systematic review and new models for children's normal maximum voided volumes.

    Science.gov (United States)

    Martínez-García, Roberto; Ubeda-Sansano, Maria Isabel; Díez-Domingo, Javier; Pérez-Hoyos, Santiago; Gil-Salom, Manuel

    2014-09-01

    There is an agreement to use simple formulae (expected bladder capacity and other age based linear formulae) as bladder capacity benchmark. But real normal child's bladder capacity is unknown. To offer a systematic review of children's normal bladder capacity, to measure children's normal maximum voided volumes (MVVs), to construct models of MVVs and to compare them with the usual formulae. Computerized, manual and grey literature were reviewed until February 2013. Epidemiological, observational, transversal, multicenter study. A consecutive sample of healthy children aged 5-14 years, attending Primary Care centres with no urologic abnormality were selected. Participants filled-in a 3-day frequency-volume chart. Variables were MVVs: maximum of 24 hr, nocturnal, and daytime maximum voided volumes. diuresis and its daytime and nighttime fractions; body-measure data; and gender. The consecutive steps method was used in a multivariate regression model. Twelve articles accomplished systematic review's criteria. Five hundred and fourteen cases were analysed. Three models, one for each of the MVVs, were built. All of them were better adjusted to exponential equations. Diuresis (not age) was the most significant factor. There was poor agreement between MVVs and usual formulae. Nocturnal and daytime maximum voided volumes depend on several factors and are different. Nocturnal and daytime maximum voided volumes should be used with different meanings in clinical setting. Diuresis is the main factor for bladder capacity. This is the first model for benchmarking normal MVVs with diuresis as its main factor. Current formulae are not suitable for clinical use. © 2013 Wiley Periodicals, Inc.

  3. Method of estimating maximum VOC concentration in void volume of vented waste drums using limited sampling data: Application in transuranic waste drums

    International Nuclear Information System (INIS)

    Liekhus, K.J.; Connolly, M.J.

    1995-01-01

    A test program has been conducted at the Idaho National Engineering Laboratory to demonstrate that the concentration of volatile organic compounds (VOCs) within the innermost layer of confinement in a vented waste drum can be estimated using a model incorporating diffusion and permeation transport principles as well as limited waste drum sampling data. The model consists of a series of material balance equations describing steady-state VOC transport from each distinct void volume in the drum. The primary model input is the measured drum headspace VOC concentration. Model parameters are determined or estimated based on available process knowledge. The model effectiveness in estimating VOC concentration in the headspace of the innermost layer of confinement was examined for vented waste drums containing different waste types and configurations. This paper summarizes the experimental measurements and model predictions in vented transuranic waste drums containing solidified sludges and solid waste

  4. THE PREDICTION OF VOID VOLUME IN SUBCOOLED NUCLEATE POOL BOILING

    Energy Technology Data Exchange (ETDEWEB)

    Duke, E. E. [General Dynamics, San Diego, CA (United States)

    1963-11-15

    A three- step equation was developed that adequately describes the average volume of vapor occurring on a horizontal surface due to nucleate pool boiling of subcooled water. Since extensive bubble frequency data are lacking, the data of others were combined with experimental observations to make predictions of void volume at ambient pressure with various degrees of subcooling. (auth)

  5. A maximum principle for the first-order Boltzmann equation, incorporating a potential treatment of voids

    International Nuclear Information System (INIS)

    Schofield, S.L.

    1988-01-01

    Ackroyd's generalized least-squares method for solving the first-order Boltzmann equation is adapted to incorporate a potential treatment of voids. The adaptation comprises a direct least-squares minimization allied with a suitably-defined bilinear functional. The resulting formulation gives rise to a maximum principle whose functional does not contain terms of the type that have previously led to difficulties in treating void regions. The maximum principle is derived without requiring continuity of the flux at interfaces. The functional of the maximum principle is concluded to have an Euler-Lagrange equation given directly by the first-order Boltzmann equation. (author)

  6. A maximum principle for time dependent transport in systems with voids

    International Nuclear Information System (INIS)

    Schofield, S.L.; Ackroyd, R.T.

    1996-01-01

    A maximum principle is developed for the first-order time dependent Boltzmann equation. The maximum principle is a generalization of Schofield's κ(θ) principle for the first-order steady state Boltzmann equation, and provides a treatment of time dependent transport in systems with void regions. The formulation comprises a direct least-squares minimization allied with a suitable choice of bilinear functional, and gives rise to a maximum principle whose functional is free of terms that have previously led to difficulties in treating void regions. (Author)

  7. Relationship between voided volume and the urge to void among patients with lower urinary tract symptoms.

    Science.gov (United States)

    Blaivas, Jerry G; Tsui, Johnson F; Amirian, Michael; Ranasinghe, Buddima; Weiss, Jeffrey P; Haukka, Jari; Tikkinen, Kari A O

    2014-12-01

    The aim of this study was to explore the relationship between voided volume (VV) and urge to void among patients with lower urinary tract symptoms. Consecutive adult patients (aged 23-90 years) were enrolled, and completed a 24 h bladder diary and the Urgency Perception Scale (UPS). Patients were categorized as urgency or non-urgency based on the Overactive Bladder Symptom Score. The relationship between UPS and VV (based on the bladder diary) was analyzed by Spearman's rho and proportional odds model. In total, 1265 micturitions were evaluated in 117 individuals (41 men, 76 women; 56 individuals in the urgency and 61 in the non-urgency group). The mean (± SD) VV and UPS were 192 ± 127 ml and 2.4 ± 1.2 ml in the urgency group and 173 ± 124 ml and 1.7 ± 1.1 ml in the non-urgency group, respectively. Spearman's rho (between UPS and VV) was 0.21 [95% confidence interval (CI) 0.13-029, p < 0.001] for the urgency group, 0.32 (95% CI 0.25-0.39, p < 0.001) for the non-urgency group, and 0.28 (95% CI 0.23-0.33, p < 0.001) for the total cohort. Urgency patients had higher UPS [odds ratio (OR) 3.1, 95% CI 2.5-3.8]. Overall, each additional 50 ml VV increased the odds of having a higher UPS with OR 1.2 (95% CI 1.2-1.3). The relationship between VV and UPS score was similar in both groups (p = 0.548 for interaction). Although urgency patients void with a higher UPS score, among both urgency and non-urgency patients there is only a weak correlation between VV and the urge to void. This suggests that there are factors other than VV that cause the urge to void.

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

    Science.gov (United States)

    Grzegorz Kossakowski, Paweł; Wciślik, Wiktor

    2017-10-01

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

  9. Laboratory test on maximum and minimum void ratio of tropical sand matrix soils

    Science.gov (United States)

    Othman, B. A.; Marto, A.

    2018-04-01

    Sand is generally known as loose granular material which has a grain size finer than gravel and coarser than silt and can be very angular to well-rounded in shape. The present of various amount of fines which also influence the loosest and densest state of sand in natural condition have been well known to contribute to the deformation and loss of shear strength of soil. This paper presents the effect of various range of fines content on minimum void ratio e min and maximum void ratio e max of sand matrix soils. Laboratory tests to determine e min and e max of sand matrix soil were conducted using non-standard method introduced by previous researcher. Clean sand was obtained from natural mining site at Johor, Malaysia. A set of 3 different sizes of sand (fine sand, medium sand, and coarse sand) were mixed with 0% to 40% by weight of low plasticity fine (kaolin). Results showed that generally e min and e max decreased with the increase of fines content up to a minimal value of 0% to 30%, and then increased back thereafter.

  10. Materials characterization of free volume and void properties by two-dimensional positron annihilation lifetime spectroscopy

    Science.gov (United States)

    Chen, Hongmin; Van Horn, J. David; Jean, Y. C.; Hung, Wei-Song; Lee, Kueir-Rarn

    2013-04-01

    Positron annihilation lifetime spectroscopy (PALS) has been widely used to determine the free volume and void properties in polymeric materials. Recently, a two dimensional positron annihilation lifetime spectroscopy (2DPALS) system has been developed for membrane applications. The system measures the coincident signals between the lifetime and the energy which could separate the 2γ and 3γ annihilations and improve the accuracy in the determination of the free volume and void properties. When 2D-PALS is used in coupling with a variable mono-energy slow positron beam, it could be applied to a variety of material characterization. Results of free volumes and voids properties in a multi-layer polymer membrane characterized using 2D-PALS are presented.

  11. Spatial variation in void volume during charged particle bombardment: the effects of injected interstitials

    International Nuclear Information System (INIS)

    Lee, E.H.; Mansur, L.K.; Yoo, M.H.

    1979-01-01

    Experimental observations of the void volume at several depths along the range of 4 MeV Ni ions in 316 stainless steel are reported. The specimens were first preconditioned by neutron irradiation at temperatures of 450 and 584 0 C to fluences of approximately 8 x 10 26 n/m -2 . The void volume after ion bombardment to 60 dpa at the peak damage depth is significantly lower at the peak damage depth than in the region between that and the free surface. The ratio of the step height to void volume at the depth of peak energy deposition between regions masked from and exposed to the beam is strongly dependent on bombardment temperature. The reduction of void volume near the peak damage depth is larger for the 584 0 C than for the 450 0 C preconditioned material. These observations are consistent with recent theoretical results which account for the injection of the bombarding ions as self-interstitials. The theory necessary to understand the effect is developed

  12. ALBEMO, a program for the calculation of the radiation transport in void volumes with reflecting walls

    International Nuclear Information System (INIS)

    Mueller, K.; Vossebrecker, H.

    The Monte Carlo Program ALBEMO calculates the distribution of neutrons and gamma rays in void volumes which are bounded by reflecting walls with x, y, z coordinates. The program is based on the albedo method. The effect of significant simplifying assumptions is investigated. Comparisons with experiments show satisfying agreement

  13. The coupled effect of fiber volume fraction and void fraction on hydraulic fluid absorption of quartz/BMI laminates

    Science.gov (United States)

    Hurdelbrink, Keith R.; Anderson, Jacob P.; Siddique, Zahed; Altan, M. Cengiz

    2016-03-01

    Bismaleimide (BMI) resin with quartz (AQ581) fiber reinforcement is a composite material frequently used in aerospace applications, such as engine cowlings and radomes. Various composite components used in aircrafts are exposed to different types of hydraulic fluids, which may lead to anomalous absorption behavior over the service life of the composite. Accurate predictive models for absorption of liquid penetrants are particularly important as the composite components are often exposed to long-term degradation due to absorbed moisture, hydraulic fluids, or similar liquid penetrants. Microstructural features such as fiber volume fraction and void fraction can have a significant effect on the absorption behavior of fiber-reinforced composites. In this paper, hydraulic fluid absorption characteristics of quartz/BMI laminates fabricated from prepregs preconditioned at different relative humidity and subsequently cured at different pressures are presented. The composite samples are immersed into hydraulic fluid at room temperature, and were not subjected to any prior degradation. To generate process-induced microvoids, prepregs were conditioned in an environmental chamber at 2% or 99% relative humidity at room temperature for a period of 24 hours prior to laminate fabrication. To alter the fiber volume fraction, the laminates were fabricated at cure pressures of 68.9 kPa (10 psi) or 482.6 kPa (70 psi) via a hot-press. The laminates are shown to have different levels of microvoids and fiber volume fractions, which were observed to affect the absorption dynamics considerably and exhibited clear non-Fickian behavior. A one-dimensional hindered diffusion model (HDM) was shown to be successful in predicting the hydraulic fluid absorption. Model prediction indicates that as the fabrication pressure increased from 68.9 kPa to 482.6 kPa, the maximum fluid content (M∞) decreased from 8.0% wt. to 1.0% wt. The degree of non-Fickian behavior, measured by hindrance coefficient (

  14. Rectangular maximum-volume submatrices and their applications

    KAUST Repository

    Mikhalev, Aleksandr; Oseledets, I.V.

    2017-01-01

    We introduce a definition of the volume of a general rectangular matrix, which is equivalent to an absolute value of the determinant for square matrices. We generalize results of square maximum-volume submatrices to the rectangular case, show a connection of the rectangular volume with an optimal experimental design and provide estimates for a growth of coefficients and an approximation error in spectral and Chebyshev norms. Three promising applications of such submatrices are presented: recommender systems, finding maximal elements in low-rank matrices and preconditioning of overdetermined linear systems. The code is available online.

  15. Rectangular maximum-volume submatrices and their applications

    KAUST Repository

    Mikhalev, Aleksandr

    2017-10-18

    We introduce a definition of the volume of a general rectangular matrix, which is equivalent to an absolute value of the determinant for square matrices. We generalize results of square maximum-volume submatrices to the rectangular case, show a connection of the rectangular volume with an optimal experimental design and provide estimates for a growth of coefficients and an approximation error in spectral and Chebyshev norms. Three promising applications of such submatrices are presented: recommender systems, finding maximal elements in low-rank matrices and preconditioning of overdetermined linear systems. The code is available online.

  16. Computing the maximum volume inscribed ellipsoid of a polytopic projection

    NARCIS (Netherlands)

    Zhen, Jianzhe; den Hertog, Dick

    We introduce a novel scheme based on a blending of Fourier-Motzkin elimination (FME) and adjustable robust optimization techniques to compute the maximum volume inscribed ellipsoid (MVE) in a polytopic projection. It is well-known that deriving an explicit description of a projected polytope is

  17. Computing the Maximum Volume Inscribed Ellipsoid of a Polytopic Projection

    NARCIS (Netherlands)

    Zhen, J.; den Hertog, D.

    2015-01-01

    We introduce a novel scheme based on a blending of Fourier-Motzkin elimination (FME) and adjustable robust optimization techniques to compute the maximum volume inscribed ellipsoid (MVE) in a polytopic projection. It is well-known that deriving an explicit description of a projected polytope is

  18. Unnoticed Post-Void Residual Urine Volume in People with Moderate to Severe Intellectual Disabilities: Prevalence and Risk Factors

    Science.gov (United States)

    de Waal, K. H.; Tinselboer, B. M.; Evenhuis, H. M.; Penning, C.

    2009-01-01

    Background: Increased post-void residual urine volume (PVR) is often seen in geriatric populations. People with intellectual disabilities (ID) have risk factors in common with these populations. Aims: To investigate in adults with ID: (1) Feasibility of portable ultrasound bladder scanning; (2) Prevalence of PVR; and (3) Relations with proposed…

  19. Prostate volume did not affect voiding function improvements in diode laser enucleation of the prostate.

    Science.gov (United States)

    Yang, Stephen Shei-Dei; Hsieh, Cheng-Hsing; Chiang, I-Ni; Lin, Chia-Da; Chang, Shang-Jen

    2013-03-01

    We compared safety and surgical outcomes in patients with different prostate sizes treated with diode laser enucleation of the prostate. From 2008 to 2012 consecutive patients with benign prostatic obstruction undergoing diode laser prostate enucleation at our institution were enrolled for analysis. A single surgeon performed diode laser prostate enucleation with an end firing, continuous wave diode laser (980 nm). Based on preoperative prostate volume on transrectal ultrasound, patients were stratified into 2 groups, including group 1-65 with less than 60 ml and group 2-55 with 60 ml or greater. Baseline and perioperative characteristics, and postoperative surgical outcomes were compared between the 2 groups. A total of 120 men with a mean ± SD age of 70.2 ± 9.0 years were enrolled for analysis. Compared with group 1 patients, those in group 2 had larger mean total prostate volume (85.0 ± 24.6 vs 40.9 ± 10.8 ml), longer mean operative time (117.7 ± 48.2 vs 60.7 ± 25.0 minutes), higher mean retrieved prostate weight (37.3 ± 16.1 vs 12.5 ± 7.3 gm) and a higher mean tissue retrieval ratio (74.4% ± 22.2% vs 58.8% ± 23.2%, p laser energy, voiding function improvements and surgical complication rates of diode laser prostate enucleation were comparable in patients with a larger vs smaller prostate. Copyright © 2013 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  20. Void Measurement by the ({gamma}, n) Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Rouhani, S Zia

    1962-09-15

    It is proposed to use the ({gamma}, n) reaction for the measurement of the integrated void volume fraction in two phase flow of D{sub 2}O inside a duct. This method is applicable to different channel geometries, and it is shown to be insensitive to the pattern of void distribution over the cross-sectional area of the channels The method has been tested on mock-ups of voids in a round duct of 6 mm inside diameter. About 40 m.c. {sup 24}Na was used as a source of gamma-rays. The test results show that the maximum measured error in this arrangement is less than 2.5 % (net void) for a range of 2.7 % to 44.44 % actual void volume fractions.

  1. Void Measurement by the (γ, n) Reaction

    International Nuclear Information System (INIS)

    Rouhani, S. Zia

    1962-09-01

    It is proposed to use the (γ, n) reaction for the measurement of the integrated void volume fraction in two phase flow of D 2 O inside a duct. This method is applicable to different channel geometries, and it is shown to be insensitive to the pattern of void distribution over the cross-sectional area of the channels The method has been tested on mock-ups of voids in a round duct of 6 mm inside diameter. About 40 m.c. 24 Na was used as a source of gamma-rays. The test results show that the maximum measured error in this arrangement is less than 2.5 % (net void) for a range of 2.7 % to 44.44 % actual void volume fractions

  2. 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.

  3. The evolution of voids in the adhesion approximation

    Science.gov (United States)

    Sahni, Varun; Sathyaprakah, B. S.; Shandarin, Sergei F.

    1994-08-01

    We apply the adhesion approximation to study the formation and evolution of voids in the universe. Our simulations-carried out using 1283 particles in a cubical box with side 128 Mpc-indicate that the void spectrum evolves with time and that the mean void size in the standard Cosmic Background Explorer Satellite (COBE)-normalized cold dark matter (CDM) model with H50 = 1 scals approximately as bar D(z) = bar Dzero/(1+2)1/2, where bar Dzero approximately = 10.5 Mpc. Interestingly, we find a strong correlation between the sizes of voids and the value of the primordial gravitational potential at void centers. This observation could in principle, pave the way toward reconstructing the form of the primordial potential from a knowledge of the observed void spectrum. Studying the void spectrum at different cosmological epochs, for spectra with a built in k-space cutoff we find that the number of voids in a representative volume evolves with time. The mean number of voids first increases until a maximum value is reached (indicating that the formation of cellular structure is complete), and then begins to decrease as clumps and filaments erge leading to hierarchical clustering and the subsequent elimination of small voids. The cosmological epoch characterizing the completion of cellular structure occurs when the length scale going nonlinear approaches the mean distance between peaks of the gravitaional potential. A central result of this paper is that voids can be populated by substructure such as mini-sheets and filaments, which run through voids. The number of such mini-pancakes that pass through a given void can be measured by the genus characteristic of an individual void which is an indicator of the topology of a given void in intial (Lagrangian) space. Large voids have on an average a larger measure than smaller voids indicating more substructure within larger voids relative to smaller ones. We find that the topology of individual voids is strongly epoch dependent

  4. Characterization of void volume VOC concentration in vented TRU waste drums - an interim report

    International Nuclear Information System (INIS)

    Liekhus, K.J.

    1994-09-01

    A test program is underway at the Idaho National Engineering Laboratory to determine if the concentration of volatile organic compounds (VOCs) in the drum headspace is representative of the VOC concentration in the entire drum void space and to demonstrate that the VOC concentration in the void space of each layer of confinement can be estimated using a model incorporating diffusion and permeation transport principles and limited waste drum sampling data. An experimental test plan was developed requiring gas sampling of 66 transuranic (TRU) waste drums. This interim report summarizes the experimental measurements and model predictions of VOC concentration in the innermost layer of confinement from waste drums sampled and analyzed in FY 1994

  5. Calculation of Void Volume Fraction in the Subcooled and Quality Boiling Regions

    Energy Technology Data Exchange (ETDEWEB)

    Rouhani, S Z; Axelsson, E

    1968-10-15

    The complex problem of void calculation in the different regions of flow boiling is divided in two parts. The first part includes only the description of the mechanisms and the calculation of the rates of heat transfer for vapour and liquid. It is assumed that heat is removed by vapour generation, heating of the liquid that replaces the detached bubbles, and in some parts, by single phase heat transfer. By considering the rate of vapour condensation in liquid, an equation for the differential changes in the true steam quality throughout the boiling regions is obtained. Integration of this equation yields the vapour weight fraction at any position. The second part of the problem concerns the determination of the void fractions corresponding to the calculated steam qualities. For this purpose we use the derivations of Zuber and Findlay. This model is compared with data from different geometries including small rectangular channels and large rod bundles. The data covered pressures from 19 to 138 bars, heat fluxes from 18 to 120 W/cm{sup 2} with many different subcoolings and mass velocities. The agreement is generally very good.

  6. Calculation of Void Volume Fraction in the Subcooled and Quality Boiling Regions

    International Nuclear Information System (INIS)

    Rouhani, S.Z.; Axelsson, E.

    1968-10-01

    The complex problem of void calculation in the different regions of flow boiling is divided in two parts. The first part includes only the description of the mechanisms and the calculation of the rates of heat transfer for vapour and liquid. It is assumed that heat is removed by vapour generation, heating of the liquid that replaces the detached bubbles, and in some parts, by single phase heat transfer. By considering the rate of vapour condensation in liquid, an equation for the differential changes in the true steam quality throughout the boiling regions is obtained. Integration of this equation yields the vapour weight fraction at any position. The second part of the problem concerns the determination of the void fractions corresponding to the calculated steam qualities. For this purpose we use the derivations of Zuber and Findlay. This model is compared with data from different geometries including small rectangular channels and large rod bundles. The data covered pressures from 19 to 138 bars, heat fluxes from 18 to 120 W/cm 2 with many different subcoolings and mass velocities. The agreement is generally very good

  7. Should measurement of maximum urinary flow rate and residual urine volume be a part of a "minimal care" assessment programme in female incontinence?

    DEFF Research Database (Denmark)

    Sander, Pia; Mouritsen, L; Andersen, J Thorup

    2002-01-01

    OBJECTIVE: The aim of this study was to evaluate the value of routine measurements of urinary flow rate and residual urine volume as a part of a "minimal care" assessment programme for women with urinary incontinence in detecting clinical significant bladder emptying problems. MATERIAL AND METHODS....... Twenty-six per cent had a maximum flow rate less than 15 ml/s, but only 4% at a voided volume > or =200 ml. Residual urine more than 149 ml was found in 6%. Two women had chronic retention with overflow incontinence. Both had typical symptoms with continuous leakage, stranguria and chronic cystitis...

  8. Maximum heat flux in boiling in a large volume

    International Nuclear Information System (INIS)

    Bergmans, Dzh.

    1976-01-01

    Relationships are derived for the maximum heat flux qsub(max) without basing on the assumptions of both the critical vapor velocity corresponding to the zero growth rate, and planar interface. The Helmholz nonstability analysis of vapor column has been made to this end. The results of this examination have been used to find maximum heat flux for spherical, cylindric and flat plate heaters. The conventional hydrodynamic theory was found to be incapable of producing a satisfactory explanation of qsub(max) for small heaters. The occurrence of qsub(max) in the present case can be explained by inadequate removal of vapor output from the heater (the force of gravity for cylindrical heaters and surface tension for the spherical ones). In case of flat plate heater the qsub(max) value can be explained with the help of the hydrodynamic theory

  9. Determination of the void nucleation rate from void size distributions

    International Nuclear Information System (INIS)

    Brailsford, A.D.

    1977-01-01

    A method of estimating the void nucleation rate from one void size distribution and from observation of the maximum void radius at prior times is proposed. Implicit in the method are the assumptions that both variations in the critical radius with dose and vacancy thermal emission processes during post-nucleation quasi-steady-state growth may be neglected. (Auth.)

  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. Void lattices

    International Nuclear Information System (INIS)

    Chadderton, L.T.; Johnson, E.; Wohlenberg, T.

    1976-01-01

    Void lattices in metals apparently owe their stability to elastically anisotropic interactions. An ordered array of voids on the anion sublattice in fluorite does not fit so neatly into this scheme of things. Crowdions may play a part in the formation of the void lattice, and stability may derive from other sources. (Auth.)

  12. The evaluation of voiding patterns. An analysis of frequency-volume charts and symptom scores

    NARCIS (Netherlands)

    Haarst, E.P. van

    2015-01-01

    This thesis is an analysis of frequency-volume charts (FVCs) and International Prostate Symptom Scores (IPSS) and their relations, based on 2 large databases: one with 24-hour FVCs of 1152 volunteers of all adult age groups without urological complaints, and one with 7-day FVCs of 378 urological

  13. Model for the evolution of the quality and ratio of the void volume for local boiling and in the transition zone (1963)

    International Nuclear Information System (INIS)

    Lavigne, P.

    1963-01-01

    A simple model giving the quality and void volume ratio valid from local boiling to bulk boiling is reported. It is based on simple hypotheses taking in account the formation and condensation of vapor. This model is especially practical for the numerical computation of designs. (author) [fr

  14. Patient preferences for clean intermittent catheterisation and transurethral indwelling catheterisation for treatment of abnormal post-void residual bladder volume after vaginal prolapse surgery

    NARCIS (Netherlands)

    Hakvoort, R. A.; Nieuwkerk, P. T.; Burger, M. P.; Emanuel, M. H.; Roovers, J. P.

    2011-01-01

    To determine patient preferences for clean intermittent catheterisation (CIC) relative to transurethral indwelling catheterisation (TIC) as the treatment of abnormal post-void residual bladder volume (PVR) following vaginal prolapse surgery. Scenario-based preference assessment during face-to-face

  15. Study on influence of flow rates on voids in waxy crude oil subjected to dynamic and static cooling

    Directory of Open Access Journals (Sweden)

    Girma T. Chala

    2015-12-01

    Full Text Available The assumption of constant yield stress in the conventional restart pressure equation neglects the effects of thermal shrinkage and gas voids formation, which in turn resulted in an over-designed production piping systems. This paper presents a study on the effects of flow rates on the formation of voids in gelled waxy crude oil. A flow loop rig simulating offshore waxy crude oil transportation was used to produce a gel. A Magnetic Resonance Imaging (MRI was used to scan the gelled crude oil over the three planes. Waxy crude oil underwent both dynamic and static cooling to observe the effects of volume flow rates on the voids formed in wax-oil gel. Volume flow rate was found to have different influences on the intra-gel voids in the pipeline. A volume flow rate of 5 L/min resulted in a maximum total voids volume of 6.98% while 20 L/min produced a minimum total voids volume of 5.67% in the entire pipe. Slow flow rates resulted in a larger voids volume near the pipe wall. In contrast, faster flow rates produced insignificantly higher voids volume around pipe core. Generally, slower flow rates favoured the formation of higher total voids volume following sufficient steady time of wax crystal formation, producing larger voids areas in gelled waxy crude oil.

  16. BASIC program to compute uranium density and void volume fraction in laboratory-scale uranium silicide aluminum dispersion plate-type fuel

    International Nuclear Information System (INIS)

    Ugajin, Mitsuhiro

    1991-05-01

    BASIC program simple and easy to operate has been developed to compute uranium density and void volume fraction for laboratory-scale uranium silicide aluminum dispersion plate-type fuel, so called miniplate. An example of the result of calculation is given in order to demonstrate how the calculated void fraction correlates with the microstructural distribution of the void in a miniplate prepared in our laboratory. The program is also able to constitute data base on important parameters for miniplates from experimentally-determined values of density, weight of each constituent and dimensions of miniplates. Utility programs pertinent to the development of the BASIC program are also given which run in the popular MS-DOS environment. All the source lists are attached and brief description for each program is made. (author)

  17. Analyzing temporal changes in maximum runoff volume series of the Danube River

    International Nuclear Information System (INIS)

    Halmova, Dana; Pekarova, Pavla; Onderka, Milan; Pekar, Jan

    2008-01-01

    Several hypotheses claim that more extremes in climatic and hydrologic phenomena are anticipated. In order to verify such hypotheses it is inevitable to examine the past periods by thoroughly analyzing historical data. In the present study, the annual maximum runoff volumes with t-day durations were calculated for a 130-year series of mean daily discharge of Danube River at Bratislava gauge (Slovakia). Statistical methods were used to clarify how the maximum runoff volumes of the Danube River changed over two historical periods (1876-1940 and 1941-2005). The conclusion is that the runoff volume regime during floods has not changed significantly during the last 130 years.

  18. SU-E-T-578: On Definition of Minimum and Maximum Dose for Target Volume

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Y; Yu, J; Xiao, Y [Thomas Jefferson University Hospital, Philadelphia, PA (United States)

    2015-06-15

    Purpose: This study aims to investigate the impact of different minimum and maximum dose definitions in radiotherapy treatment plan quality evaluation criteria by using tumor control probability (TCP) models. Methods: Dosimetric criteria used in RTOG 1308 protocol are used in the investigation. RTOG 1308 is a phase III randomized trial comparing overall survival after photon versus proton chemoradiotherapy for inoperable stage II-IIIB NSCLC. The prescription dose for planning target volume (PTV) is 70Gy. Maximum dose (Dmax) should not exceed 84Gy and minimum dose (Dmin) should not go below 59.5Gy in order for the plan to be “per protocol” (satisfactory).A mathematical model that simulates the characteristics of PTV dose volume histogram (DVH) curve with normalized volume is built. The Dmax and Dmin are noted as percentage volumes Dη% and D(100-δ)%, with η and d ranging from 0 to 3.5. The model includes three straight line sections and goes through four points: D95%= 70Gy, Dη%= 84Gy, D(100-δ)%= 59.5 Gy, and D100%= 0Gy. For each set of η and δ, the TCP value is calculated using the inhomogeneously irradiated tumor logistic model with D50= 74.5Gy and γ50=3.52. Results: TCP varies within 0.9% with η; and δ values between 0 and 1. With η and η varies between 0 and 2, TCP change was up to 2.4%. With η and δ variations from 0 to 3.5, maximum of 8.3% TCP difference is seen. Conclusion: When defined maximum and minimum volume varied more than 2%, significant TCP variations were seen. It is recommended less than 2% volume used in definition of Dmax or Dmin for target dosimetric evaluation criteria. This project was supported by NIH grants U10CA180868, U10CA180822, U24CA180803, U24CA12014 and PA CURE Grant.

  19. SU-E-T-578: On Definition of Minimum and Maximum Dose for Target Volume

    International Nuclear Information System (INIS)

    Gong, Y; Yu, J; Xiao, Y

    2015-01-01

    Purpose: This study aims to investigate the impact of different minimum and maximum dose definitions in radiotherapy treatment plan quality evaluation criteria by using tumor control probability (TCP) models. Methods: Dosimetric criteria used in RTOG 1308 protocol are used in the investigation. RTOG 1308 is a phase III randomized trial comparing overall survival after photon versus proton chemoradiotherapy for inoperable stage II-IIIB NSCLC. The prescription dose for planning target volume (PTV) is 70Gy. Maximum dose (Dmax) should not exceed 84Gy and minimum dose (Dmin) should not go below 59.5Gy in order for the plan to be “per protocol” (satisfactory).A mathematical model that simulates the characteristics of PTV dose volume histogram (DVH) curve with normalized volume is built. The Dmax and Dmin are noted as percentage volumes Dη% and D(100-δ)%, with η and d ranging from 0 to 3.5. The model includes three straight line sections and goes through four points: D95%= 70Gy, Dη%= 84Gy, D(100-δ)%= 59.5 Gy, and D100%= 0Gy. For each set of η and δ, the TCP value is calculated using the inhomogeneously irradiated tumor logistic model with D50= 74.5Gy and γ50=3.52. Results: TCP varies within 0.9% with η; and δ values between 0 and 1. With η and η varies between 0 and 2, TCP change was up to 2.4%. With η and δ variations from 0 to 3.5, maximum of 8.3% TCP difference is seen. Conclusion: When defined maximum and minimum volume varied more than 2%, significant TCP variations were seen. It is recommended less than 2% volume used in definition of Dmax or Dmin for target dosimetric evaluation criteria. This project was supported by NIH grants U10CA180868, U10CA180822, U24CA180803, U24CA12014 and PA CURE Grant

  20. Selection of magnetorheological brake types via optimal design considering maximum torque and constrained volume

    International Nuclear Information System (INIS)

    Nguyen, Q H; Choi, S B

    2012-01-01

    This research focuses on optimal design of different types of magnetorheological brakes (MRBs), from which an optimal selection of MRB types is identified. In the optimization, common types of MRB such as disc-type, drum-type, hybrid-types, and T-shaped type are considered. The optimization problem is to find the optimal value of significant geometric dimensions of the MRB that can produce a maximum braking torque. The MRB is constrained in a cylindrical volume of a specific radius and length. After a brief description of the configuration of MRB types, the braking torques of the MRBs are derived based on the Herschel–Bulkley model of the MR fluid. The optimal design of MRBs constrained in a specific cylindrical volume is then analysed. The objective of the optimization is to maximize the braking torque while the torque ratio (the ratio of maximum braking torque and the zero-field friction torque) is constrained to be greater than a certain value. A finite element analysis integrated with an optimization tool is employed to obtain optimal solutions of the MRBs. Optimal solutions of MRBs constrained in different volumes are obtained based on the proposed optimization procedure. From the results, discussions on the optimal selection of MRB types depending on constrained volumes are given. (paper)

  1. Provision of financial transmission rights including assessment of maximum volumes of obligations and options

    International Nuclear Information System (INIS)

    Kristiansen, Tarjei

    2007-01-01

    This paper studies the risks faced by the providers of financial transmission rights (FTRs). The introduction of FTRs in different systems in the USA must be viewed in relationship to the organization of the market. Often, private players own the central grid, while an independent system operator (ISO) operates the grid. The revenues from transmission congestion collected in the day-ahead and balancing markets should give the ISO sufficient revenues to cover the costs associated with providing FTRs. This can be ensured if the issued FTRs fulfill the simultaneous feasibility test described by Hogan. This test on a three-node network is studied under different assumptions to find the maximum volumes, which can be sold, including contingency constraints. Next the feasibility test is analyzed when taking into account the proceeds from the FTR auction, and demonstrates that a higher volume might be issued. We introduce uncertainty under different scenarios for locational prices and calculate the maximum provided volumes. As a tool for risk management, the provider of the FTRs can use the Value at Risk approach. Finally, the provision of FTRs by private parties is discussed. (author)

  2. The effect of impression volume and double-arch trays on the registration of maximum intercuspation.

    Science.gov (United States)

    Hahn, Sara M; Millstein, Philip L; Kinnunen, Taru H; Wright, Robert F

    2009-12-01

    The type of double-arch trays used may affect occlusion. The purpose of this study was to determine what effect, if any, double-arch tray design and impression material volume had on the registration of maximum intercuspation (MI). Quadrant impressions were made on articulated fracture-resistant dental casts mounted in maximum intercuspation occlusion. Three types of sideless double-arch impression trays were used: First Bite with nylon webbing, Sultan's 3-Way with double crosshatch webbing, and Premium's 3-in-1 Tray with single crosshatch webbing. Vinyl polysiloxane impression material (Aquasil Ultra Rigid Fast Set) was distributed at 2 different volumes (5.4 ml and 8.3 ml), and 60 impressions were made (n=10). A weight of 1.2 kg was placed on the upper arm of an Artex articulator, ensuring complete closure. The impressions were allowed to polymerize for 5 minutes. After polymerization, specimens were placed on a light box, and a camera set at a fixed distance was used to capture the light transmission that was projected through the impression material. The camera transferred the information to an image analysis program (ImageJ). This system allowed the different amounts of light projected through the impression to be translated into a gray scale value (GSV), which was assigned a thickness value, in millimeters, of a specified occlusal contact area. To assess reliability of the experimental design, 10 control impressions were made by directly applying impression material onto the typodont. These were analyzed in the same manner as the impressions made with trays. A 2-way ANOVA comparing volume by tray type was used (alpha=.05). This was followed by a Tukey HSD test. There was no main effect for volume of impression material (P=.71). Tray type was significantly different (Precord making.

  3. Nucleation from a cluster of inclusions, leading to void coalescense

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    2017-01-01

    A cell model analysis is used to study the nucleation and subsequent growth of voids from a non-uniform distribution of inclusions in a ductile material. Nucleation is modeled as either stress controlled or strain controlled. The special clusters considered consist of a number of uniformly spaced...... inclusions located along a plane perpendicular to the maximum principal tensile stress. A plane strain approximation is used, where the inclusions are parallel cylinders perpendicular to the plane. Clusters with different numbers of inclusions are compared with the nucleation and growth from a single...... inclusion, such that the total initial volume of the inclusions is the same for the clusters and the single inclusion. After nucleation, local void coalescence inside the clusters is accounted for, since this makes it possible to compare the rate of growth of the single larger void that results from...

  4. Pulmonary nodules: sensitivity of maximum intensity projection versus that of volume rendering of 3D multidetector CT data

    NARCIS (Netherlands)

    Peloschek, Philipp; Sailer, Johannes; Weber, Michael; Herold, Christian J.; Prokop, Mathias; Schaefer-Prokop, Cornelia

    2007-01-01

    PURPOSE: To prospectively compare maximum intensity projection (MIP) and volume rendering (VR) of multidetector computed tomographic (CT) data for the detection of small intrapulmonary nodules. MATERIALS AND METHODS: This institutional review board-approved prospective study included 20 oncology

  5. cExternal beam radiation results in minimal changes in post void residual urine volumes during the treatment of clinically localized prostate cancer

    International Nuclear Information System (INIS)

    Orio, Peter F III; Merrick, Gregory S; Allen, Zachariah A; Butler, Wayne M; Wallner, Kent E; Kurko, Brian S; Galbreath, Robert W

    2009-01-01

    To evaluate the impact of external beam radiation therapy (XRT) on weekly ultrasound determined post-void residual (PVR) urine volumes in patients with prostate cancer. 125 patients received XRT for clinically localized prostate cancer. XRT was delivered to the prostate only (n = 66) or if the risk of lymph node involvement was greater than 10% to the whole pelvis followed by a prostate boost (n = 59). All patients were irradiated in the prone position in a custom hip-fix mobilization device with an empty bladder and rectum. PVR was obtained at baseline and weekly. Multiple clinical and treatment parameters were evaluated as predictors for weekly PVR changes. The mean patient age was 73.9 years with a mean pre-treatment prostate volume of 53.3 cc, a mean IPSS of 11.3 and a mean baseline PVR of 57.6 cc. During treatment, PVR decreased from baseline in both cohorts with the absolute difference within the limits of accuracy of the bladder scanner. Alpha-blockers did not predict for a lower PVR during treatment. There was no significant difference in mean PVR urine volumes or differences from baseline in either the prostate only or pelvic radiation groups (p = 0.664 and p = 0.458, respectively). Patients with a larger baseline PVR (>40 cc) had a greater reduction in PVR, although the greatest reduction was seen between weeks one and three. Patients with a small PVR (<40 cc) had no demonstrable change throughout treatment. Prostate XRT results in clinically insignificant changes in weekly PVR volumes, suggesting that radiation induced bladder irritation does not substantially influence bladder residual urine volumes

  6. cExternal beam radiation results in minimal changes in post void residual urine volumes during the treatment of clinically localized prostate cancer

    Directory of Open Access Journals (Sweden)

    Wallner Kent E

    2009-07-01

    Full Text Available Abstract Background To evaluate the impact of external beam radiation therapy (XRT on weekly ultrasound determined post-void residual (PVR urine volumes in patients with prostate cancer. Methods 125 patients received XRT for clinically localized prostate cancer. XRT was delivered to the prostate only (n = 66 or if the risk of lymph node involvement was greater than 10% to the whole pelvis followed by a prostate boost (n = 59. All patients were irradiated in the prone position in a custom hip-fix mobilization device with an empty bladder and rectum. PVR was obtained at baseline and weekly. Multiple clinical and treatment parameters were evaluated as predictors for weekly PVR changes. Results The mean patient age was 73.9 years with a mean pre-treatment prostate volume of 53.3 cc, a mean IPSS of 11.3 and a mean baseline PVR of 57.6 cc. During treatment, PVR decreased from baseline in both cohorts with the absolute difference within the limits of accuracy of the bladder scanner. Alpha-blockers did not predict for a lower PVR during treatment. There was no significant difference in mean PVR urine volumes or differences from baseline in either the prostate only or pelvic radiation groups (p = 0.664 and p = 0.458, respectively. Patients with a larger baseline PVR (>40 cc had a greater reduction in PVR, although the greatest reduction was seen between weeks one and three. Patients with a small PVR ( Conclusion Prostate XRT results in clinically insignificant changes in weekly PVR volumes, suggesting that radiation induced bladder irritation does not substantially influence bladder residual urine volumes.

  7. NUPEC BWR Full-size Fine-mesh Bundle Test (BFBT) Benchmark. Volume II: uncertainty and sensitivity analyses of void distribution and critical power - Specification

    International Nuclear Information System (INIS)

    Aydogan, F.; Hochreiter, L.; Ivanov, K.; Martin, M.; Utsuno, H.; Sartori, E.

    2010-01-01

    experimental cases from the BFBT database for both steady-state void distribution and steady-state critical power uncertainty analyses. In order to study the basic thermal-hydraulics in a single channel, where the concern regarding the cross-flow effect modelling could be removed, an elemental task is proposed, consisting of two sub-tasks that are placed in each phase of the benchmark scope as follows: - Sub-task 1: Void fraction in elemental channel benchmark; - Sub-task 2: Critical power in elemental channel benchmark. The first task can also be utilised as an uncertainty analysis exercise for fine computational fluid dynamics (CFD) models for which the full bundle sensitivity or uncertainty analysis is more difficult. The task is added to the second volume of the specification as an optional exercise. Chapter 2 of this document provides the definition of UA/SA terms. Chapter 3 provides the selection and characterisation of the input uncertain parameters for the BFBT benchmark and the description of the elemental task. Chapter 4 describes the suggested approach for UA/SA of the BFBT benchmark. Chapter 5 provides the selection of data sets for the uncertainty analysis and the elemental task from the BFBT database. Chapter 6 specifies the requested output for void distribution and critical power uncertainty analyses (Exercises I-4 and II-3) as well as for the elemental task. Chapter 7 provides conclusions. Appendix 1 discusses the UA/SA methods. Appendix 2 presents the Phenomena Identification Ranking Tables (PIRT) developed at PSU for void distribution and critical power predictions in order to assist participants in selecting the most sensitive/uncertain code model parameters

  8. 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...

  9. On the abundance of extreme voids II: a survey of void mass functions

    International Nuclear Information System (INIS)

    Chongchitnan, Siri; Hunt, Matthew

    2017-01-01

    The abundance of cosmic voids can be described by an analogue of halo mass functions for galaxy clusters. In this work, we explore a number of void mass functions: from those based on excursion-set theory to new mass functions obtained by modifying halo mass functions. We show how different void mass functions vary in their predictions for the largest void expected in an observational volume, and compare those predictions to observational data. Our extreme-value formalism is shown to be a new practical tool for testing void theories against simulation and observation.

  10. Dynamic void behavior in polymerizing polymethyl methacrylate cement.

    Science.gov (United States)

    Muller, Scott D; McCaskie, Andrew W

    2006-02-01

    Cement mantle voids remain controversial with respect to survival of total hip arthroplasty. Void evolution is poorly understood, and attempts at void manipulation can only be empirical. We induced voids in a cement model simulating the constraints of the proximal femur. Intravoid pressure and temperature were recorded throughout polymerization, and the initial and final void volumes were measured. Temperature-dependent peak intravoid pressures and void volume increases were observed. After solidification, subatmospheric intravoid pressures were observed. The magnitude of these observations could not be explained by the ideal gas law. Partial pressures of the void gas at peak pressures demonstrated a dominant effect of gaseous monomer, thereby suggesting that void growth is a pressure-driven phenomenon resulting from temperature-dependent evaporation of monomer into existing trapped air voids.

  11. Software quality assurance plan for void fraction instrument

    International Nuclear Information System (INIS)

    Gimera, M.

    1994-01-01

    Waste Tank SY-101 has been the focus of extensive characterization work over the past few years. The waste continually generates gases, most notably hydrogen, which are periodically released from the waste. Gas can be trapped in tank waste in three forms: as void gas (bubbles), dissolved gas, or absorbed gas. Void fraction is the volume percentage of a given sample that is comprised of void gas. The void fraction instrument (VFI) acquires the data necessary to calculate void fraction. This document covers the product, Void Fraction Data Acquisition Software. The void fraction software being developed will have the ability to control the void fraction instrument hardware and acquire data necessary to calculate the void fraction in samples. This document provides the software quality assurance plan, verification and validation plan, and configuration management plan for developing the software for the instrumentation that will be used to obtain void fraction data from Tank SY-101

  12. Elastic wave scattering from multiple voids (porosity)

    International Nuclear Information System (INIS)

    Thompson, D.O.; Rose, J.H.; Thompson, R.B.; Wormley, S.J.

    1983-01-01

    This paper describes the development of an ultrasonic backscatter measurement technique which provides a convenient way to determine certain characteristics of a distribution of voids (porosity) in materials. A typical ultrasonic sample prepared by placing the ''frit'' in a crucible in an RF induction heater is shown. The results of the measurements were Fourier transformed into an amplitude-frequency description, and were then deconvolved with the transducer response function. Several properties needed to characterize a void distribution are obtained from the experimental results, including average void size, the spatial extent of the voids region, the average void separation, and the volume fraction of material contained in the void distribution. A detailed comparison of values obtained from the ultrasonic measurements with visually determined results is also given

  13. 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.

  14. Partial discharges in spheroidal voids: Void orientation

    DEFF Research Database (Denmark)

    McAllister, Iain Wilson

    1997-01-01

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

  15. Pediatric Voiding Cystourethrogram

    Science.gov (United States)

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

  16. Cosmic void clumps

    Science.gov (United States)

    Lares, M.; Luparello, H. E.; Garcia Lambas, D.; Ruiz, A. N.; Ceccarelli, L.; Paz, D.

    2017-10-01

    Cosmic voids are of great interest given their relation to the large scale distribution of mass and the way they trace cosmic flows shaping the cosmic web. Here we show that the distribution of voids has, in consonance with the distribution of mass, a characteristic scale at which void pairs are preferentially located. We identify clumps of voids with similar environments and use them to define second order underdensities. Also, we characterize its properties and analyze its impact on the cosmic microwave background.

  17. Elevated post-void residual volume in a geriatric post-hip fracture assessment in women-associated factors and risk of mortality.

    Science.gov (United States)

    Nuotio, Maria S; Luukkaala, Tiina; Tammela, Teuvo

    2018-04-09

    Multiple factors contribute to elevated post-void residual urine volumes (PVR), but they may indicate detrusor underactivity (DU), especially in older women. The aim here was to examine factors associated with and prognostic significance of elevated PVR in a geriatric post-hip fracture assessment in a female population. Consecutive female hip fracture patients (n = 409) aged 65 years and older were included. PVR was measured by bladder scanner. PVR of 160 ml or more was deemed elevated. Age-adjusted univariate logistic regression analyses were conducted to examine the association of the domains of the comprehensive geriatric assessment (CGA) with elevated PVR. Cox proportional hazards model was used to determine the age-adjusted association of an elevated PVR with 1-year mortality. Of the patients, 64 (15.6%) had elevated PVR. Having urinary or fecal incontinence, difficulties in physical activities of daily living, malnutrition, poor performance on Timed Up and Go and Elderly Mobility Scale were significantly associated with elevated PVR. Difficulties in instrumental activities of daily living, renal dysfunction, constipation, polypharmacy, nocturia, cognitive impairment and depressive mood were not associated with elevated PVR. Elevated PVR significantly increased the risk of mortality 1 year post hip fracture. Elevated PVR is relatively common in older female hip fracture patients and associated with physical functioning, malnutrition and risk of mortality. Even though a causal relationship cannot be confirmed, the findings may suggest a relationship between DU and physical frailty. PVR deserves to be included in the CGA of frail older patients including women.

  18. International Benchmark on Pressurised Water Reactor Sub-channel and Bundle Tests. Volume II: Benchmark Results of Phase I: Void Distribution

    International Nuclear Information System (INIS)

    Rubin, Adam; Avramova, Maria; Velazquez-Lozada, Alexander

    2016-03-01

    This report summarised the first phase of the Nuclear Energy Agency (NEA) and the US Nuclear Regulatory Commission Benchmark based on NUPEC PWR Sub-channel and Bundle Tests (PSBT), which was intended to provide data for the verification of void distribution models in participants' codes. This phase was composed of four exercises; Exercise 1: steady-state single sub-channel benchmark, Exercise 2: steady-state rod bundle benchmark, Exercise 3: transient rod bundle benchmark and Exercise 4: a pressure drop benchmark. The experimental data provided to the participants of this benchmark is from a series of void measurement tests using full-size mock-up tests for both Boiling Water Reactors (BWRs) and Pressurised Water Reactors (PWRs). These tests were performed from 1987 to 1995 by the Nuclear Power Engineering Corporation (NUPEC) in Japan and made available by the Japan Nuclear Energy Safety Organisation (JNES) for the purposes of this benchmark, which was organised by Pennsylvania State University. Twenty-one institutions from nine countries participated in this benchmark. Seventeen different computer codes were used in Exercises 1, 2, 3 and 4. Among the computer codes were porous media, sub-channel, systems thermal-hydraulic code and Computational Fluid Dynamics (CFD) codes. It was observed that the codes tended to overpredict the thermal equilibrium quality at lower elevations and under predict it at higher elevations. There was also a tendency to overpredict void fraction at lower elevations and underpredict it at high elevations for the bundle test cases. The overprediction of void fraction at low elevations is likely caused by the x-ray densitometer measurement method used. Under sub-cooled boiling conditions, the voids accumulate at heated surfaces (and are therefore not seen in the centre of the sub-channel, where the measurements are being taken), so the experimentally-determined void fractions will be lower than the actual void fraction. Some of the best

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

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof

    2008-01-01

    of different material length parameters in a multi-parameter theory is studied, and it is shown that the important length parameter is the same as under purely hydrostatic loading. It is quantified how micron scale voids grow less rapidly than larger voids, and the implications of this in the overall strength...... of the material is emphasized. The size effect on the onset of coalescence is studied, and results for the void volume fraction and the strain at the onset of coalescence are presented. It is concluded that for cracked specimens not only the void volume fraction, but also the typical void size is of importance...... to the fracture strength of ductile materials....

  20. Optimum coil shape for a given volume of conductor to obtain maximum central field in an air core solenoid

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, P. [Lawrence Berkeley Lab., CA (United States)

    1995-02-01

    This paper is an expansion of engineering notes prepared in 1961 to address the question of how to wind circular coils so as to obtain the maximum axial field with the minimum volume of conductor. At the time this was a germain question because of the advent of superconducting wires which were in very limited supply, and the rapid push for generation of very high fields, with little concern for uniformity.

  1. Statistics and geometry of cosmic voids

    International Nuclear Information System (INIS)

    Gaite, José

    2009-01-01

    We introduce new statistical methods for the study of cosmic voids, focusing on the statistics of largest size voids. We distinguish three different types of distributions of voids, namely, Poisson-like, lognormal-like and Pareto-like distributions. The last two distributions are connected with two types of fractal geometry of the matter distribution. Scaling voids with Pareto distribution appear in fractal distributions with box-counting dimension smaller than three (its maximum value), whereas the lognormal void distribution corresponds to multifractals with box-counting dimension equal to three. Moreover, voids of the former type persist in the continuum limit, namely, as the number density of observable objects grows, giving rise to lacunar fractals, whereas voids of the latter type disappear in the continuum limit, giving rise to non-lacunar (multi)fractals. We propose both lacunar and non-lacunar multifractal models of the cosmic web structure of the Universe. A non-lacunar multifractal model is supported by current galaxy surveys as well as cosmological N-body simulations. This model suggests, in particular, that small dark matter halos and, arguably, faint galaxies are present in cosmic voids

  2. On void nucleation

    International Nuclear Information System (INIS)

    Subbotin, A.V.

    1978-01-01

    Nucleation of viable voids in irradiated materials is considered. The mechanism of evaporation and absorption of interstitials and vacancies disregarding the possibility of void merging is laid down into the basis of the discussion. The effect of irradiated material structure on void nucleation is separated from the effect of the properties of supersaturated solutions of vacancies and interstitials. An analytical expression for the nucleation rate is obtained and analyzed in different cases. The interstitials are concluded to effect severely the nucleation rate of viable voids

  3. Sea level and global ice volumes from the Last Glacial Maximum to the Holocene.

    Science.gov (United States)

    Lambeck, Kurt; Rouby, Hélène; Purcell, Anthony; Sun, Yiying; Sambridge, Malcolm

    2014-10-28

    The major cause of sea-level change during ice ages is the exchange of water between ice and ocean and the planet's dynamic response to the changing surface load. Inversion of ∼1,000 observations for the past 35,000 y from localities far from former ice margins has provided new constraints on the fluctuation of ice volume in this interval. Key results are: (i) a rapid final fall in global sea level of ∼40 m in sea level, the main phase of deglaciation occurred from ∼16.5 ka BP to ∼8.2 ka BP at an average rate of rise of 12 m⋅ka(-1) punctuated by periods of greater, particularly at 14.5-14.0 ka BP at ≥40 mm⋅y(-1) (MWP-1A), and lesser, from 12.5 to 11.5 ka BP (Younger Dryas), rates; (iv) no evidence for a global MWP-1B event at ∼11.3 ka BP; and (v) a progressive decrease in the rate of rise from 8.2 ka to ∼2.5 ka BP, after which ocean volumes remained nearly constant until the renewed sea-level rise at 100-150 y ago, with no evidence of oscillations exceeding ∼15-20 cm in time intervals ≥200 y from 6 to 0.15 ka BP.

  4. Temperature controlled 'void' formation

    International Nuclear Information System (INIS)

    Dasgupta, P.; Sharma, B.D.

    1975-01-01

    The nucleation and growth of voids in structural materials during high temperature deformation or irradiation is essentially dependent upon the existence of 'vacancy supersaturation'. The role of temperature dependent diffusion processes in 'void' formation under varying conditions, and the mechanical property changes associated with this microstructure are briefly reviewed. (author)

  5. Void nucleation at heterogeneities

    International Nuclear Information System (INIS)

    Seyyedi, S.A.; Hadji-Mirzai, M.; Russell, K.C.

    The energetics and kinetics of void nucleation at dislocations and interfaces are analyzed. These are potential void nucleation sites only when they are not point defect sinks. Both kinds of site are found to be excellent catalysts in the presence of inert gas

  6. County-Level Climate Uncertainty for Risk Assessments: Volume 4 Appendix C - Historical Maximum Near-Surface Air Temperature.

    Energy Technology Data Exchange (ETDEWEB)

    Backus, George A.; Lowry, Thomas Stephen; Jones, Shannon M; Walker, La Tonya Nicole; Roberts, Barry L; Malczynski, Leonard A.

    2017-06-01

    This report uses the CMIP5 series of climate model simulations to produce country- level uncertainty distributions for use in socioeconomic risk assessments of climate change impacts. It provides appropriate probability distributions, by month, for 169 countries and autonomous-areas on temperature, precipitation, maximum temperature, maximum wind speed, humidity, runoff, soil moisture and evaporation for the historical period (1976-2005), and for decadal time periods to 2100. It also provides historical and future distributions for the Arctic region on ice concentration, ice thickness, age of ice, and ice ridging in 15-degree longitude arc segments from the Arctic Circle to 80 degrees latitude, plus two polar semicircular regions from 80 to 90 degrees latitude. The uncertainty is meant to describe the lack of knowledge rather than imprecision in the physical simulation because the emphasis is on unfalsified risk and its use to determine potential socioeconomic impacts. The full report is contained in 27 volumes.

  7. County-Level Climate Uncertainty for Risk Assessments: Volume 18 Appendix Q - Historical Maximum Near-Surface Wind Speed.

    Energy Technology Data Exchange (ETDEWEB)

    Backus, George A.; Lowry, Thomas Stephen; Jones, Shannon M; Walker, La Tonya Nicole; Roberts, Barry L; Malczynski, Leonard A.

    2017-06-01

    This report uses the CMIP5 series of climate model simulations to produce country- level uncertainty distributions for use in socioeconomic risk assessments of climate change impacts. It provides appropriate probability distributions, by month, for 169 countries and autonomous-areas on temperature, precipitation, maximum temperature, maximum wind speed, humidity, runoff, soil moisture and evaporation for the historical period (1976-2005), and for decadal time periods to 2100. It also provides historical and future distributions for the Arctic region on ice concentration, ice thickness, age of ice, and ice ridging in 15-degree longitude arc segments from the Arctic Circle to 80 degrees latitude, plus two polar semicircular regions from 80 to 90 degrees latitude. The uncertainty is meant to describe the lack of knowledge rather than imprecision in the physical simulation because the emphasis is on unfalsified risk and its use to determine potential socioeconom ic impacts. The full report is contained in 27 volumes.

  8. Validation of a 4D-PET Maximum Intensity Projection for Delineation of an Internal Target Volume

    Energy Technology Data Exchange (ETDEWEB)

    Callahan, Jason, E-mail: jason.callahan@petermac.org [Centre for Molecular Imaging, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia); Kron, Tomas [Department of Physical Sciences, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia); Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne (Australia); Schneider-Kolsky, Michal [Department of Medical Imaging and Radiation Science, Monash University, Clayton, Victoria (Australia); Dunn, Leon [Department of Applied Physics, RMIT University, Melbourne (Australia); Thompson, Mick [Centre for Molecular Imaging, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia); Siva, Shankar [Department of Radiation Oncology, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia); Aarons, Yolanda [Department of Radiation Oncology, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia); Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne (Australia); Binns, David [Centre for Molecular Imaging, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia); Hicks, Rodney J. [Centre for Molecular Imaging, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia); Peter MacCallum Department of Oncology, The University of Melbourne, Melbourne (Australia)

    2013-07-15

    Purpose: The delineation of internal target volumes (ITVs) in radiation therapy of lung tumors is currently performed by use of either free-breathing (FB) {sup 18}F-fluorodeoxyglucose-positron emission tomography-computed tomography (FDG-PET/CT) or 4-dimensional (4D)-CT maximum intensity projection (MIP). In this report we validate the use of 4D-PET-MIP for the delineation of target volumes in both a phantom and in patients. Methods and Materials: A phantom with 3 hollow spheres was prepared surrounded by air then water. The spheres and water background were filled with a mixture of {sup 18}F and radiographic contrast medium. A 4D-PET/CT scan was performed of the phantom while moving in 4 different breathing patterns using a programmable motion device. Nine patients with an FDG-avid lung tumor who underwent FB and 4D-PET/CT and >5 mm of tumor motion were included for analysis. The 3 spheres and patient lesions were contoured by 2 contouring methods (40% of maximum and PET edge) on the FB-PET, FB-CT, 4D-PET, 4D-PET-MIP, and 4D-CT-MIP. The concordance between the different contoured volumes was calculated using a Dice coefficient (DC). The difference in lung tumor volumes between FB-PET and 4D-PET volumes was also measured. Results: The average DC in the phantom using 40% and PET edge, respectively, was lowest for FB-PET/CT (DCAir = 0.72/0.67, DCBackground 0.63/0.62) and highest for 4D-PET/CT-MIP (DCAir = 0.84/0.83, DCBackground = 0.78/0.73). The average DC in the 9 patients using 40% and PET edge, respectively, was also lowest for FB-PET/CT (DC = 0.45/0.44) and highest for 4D-PET/CT-MIP (DC = 0.72/0.73). In the 9 lesions, the target volumes of the FB-PET using 40% and PET edge, respectively, were on average 40% and 45% smaller than the 4D-PET-MIP. Conclusion: A 4D-PET-MIP produces volumes with the highest concordance with 4D-CT-MIP across multiple breathing patterns and lesion sizes in both a phantom and among patients. Freebreathing PET/CT consistently

  9. Validation of a 4D-PET Maximum Intensity Projection for Delineation of an Internal Target Volume

    International Nuclear Information System (INIS)

    Callahan, Jason; Kron, Tomas; Schneider-Kolsky, Michal; Dunn, Leon; Thompson, Mick; Siva, Shankar; Aarons, Yolanda; Binns, David; Hicks, Rodney J.

    2013-01-01

    Purpose: The delineation of internal target volumes (ITVs) in radiation therapy of lung tumors is currently performed by use of either free-breathing (FB) 18 F-fluorodeoxyglucose-positron emission tomography-computed tomography (FDG-PET/CT) or 4-dimensional (4D)-CT maximum intensity projection (MIP). In this report we validate the use of 4D-PET-MIP for the delineation of target volumes in both a phantom and in patients. Methods and Materials: A phantom with 3 hollow spheres was prepared surrounded by air then water. The spheres and water background were filled with a mixture of 18 F and radiographic contrast medium. A 4D-PET/CT scan was performed of the phantom while moving in 4 different breathing patterns using a programmable motion device. Nine patients with an FDG-avid lung tumor who underwent FB and 4D-PET/CT and >5 mm of tumor motion were included for analysis. The 3 spheres and patient lesions were contoured by 2 contouring methods (40% of maximum and PET edge) on the FB-PET, FB-CT, 4D-PET, 4D-PET-MIP, and 4D-CT-MIP. The concordance between the different contoured volumes was calculated using a Dice coefficient (DC). The difference in lung tumor volumes between FB-PET and 4D-PET volumes was also measured. Results: The average DC in the phantom using 40% and PET edge, respectively, was lowest for FB-PET/CT (DCAir = 0.72/0.67, DCBackground 0.63/0.62) and highest for 4D-PET/CT-MIP (DCAir = 0.84/0.83, DCBackground = 0.78/0.73). The average DC in the 9 patients using 40% and PET edge, respectively, was also lowest for FB-PET/CT (DC = 0.45/0.44) and highest for 4D-PET/CT-MIP (DC = 0.72/0.73). In the 9 lesions, the target volumes of the FB-PET using 40% and PET edge, respectively, were on average 40% and 45% smaller than the 4D-PET-MIP. Conclusion: A 4D-PET-MIP produces volumes with the highest concordance with 4D-CT-MIP across multiple breathing patterns and lesion sizes in both a phantom and among patients. Freebreathing PET/CT consistently underestimates ITV

  10. Void hierarchy and cosmic structure

    International Nuclear Information System (INIS)

    Weygaert, Rien van de; Ravi Sheth

    2004-01-01

    Within the context of hierarchical scenarios of gravitational structure formation we describe how an evolving hierarchy of voids evolves on the basis of two processes, the void-in-void process and the void-in-cloud process. The related analytical formulation in terms of a two-barrier excursion problem leads to a self-similarly evolving peaked void size distribution

  11. VIDE: The Void IDentification and Examination toolkit

    Science.gov (United States)

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

    2015-03-01

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

  12. Time dependent voiding mechanisms in polyamide 6 submitted to high stress triaxiality: experimental characterisation and finite element modelling

    Science.gov (United States)

    Selles, Nathan; King, Andrew; Proudhon, Henry; Saintier, Nicolas; Laiarinandrasana, Lucien

    2017-08-01

    Double notched round bars made of semi-crystalline polymer polyamide 6 (PA6) were submitted to monotonic tensile and creep tests. The two notches had a root radius of 0.45 mm, which imposes a multiaxial stress state and a state of high triaxiality in the net (minimal) section of the specimens. Tests were carried out until the failure occurred from one of the notches. The other one, unbroken but deformed under steady strain rate or steady load, was inspected using the Synchrotron Radiation Computed Tomography (SRCT) technique. These 3D through thickness inspections allowed the study of microstructural evolution at the peak stress for the monotonic tensile test and at the beginning of the tertiary creep for the creep tests. Cavitation features were assessed with a micrometre resolution within the notched region. Spatial distributions of void volume fraction ( Vf) and void morphology were studied. Voiding mechanisms were similar under steady strain rates and steady loads. The maximum values of Vf were located between the axis of revolution of the specimens and the notch surface and voids were considered as flat cylinders with a circular basis perpendicular to the loading direction. A model, based on porous plasticity, was used to simulate the mechanical response of this PA6 material under high stress triaxiality. Both macroscopic behaviour (loading curves) and voiding micro-mechanisms (radial distributions of void volume fraction) were accurately predicted using finite element simulations.

  13. Air void clustering.

    Science.gov (United States)

    2015-06-01

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

  14. On the observability of coupled dark energy with cosmic voids

    Science.gov (United States)

    Sutter, P. M.; Carlesi, Edoardo; Wandelt, Benjamin D.; Knebe, Alexander

    2015-01-01

    Taking N-body simulations with volumes and particle densities tuned to match the sloan digital sky survey DR7 spectroscopic main sample, we assess the ability of current void catalogues to distinguish a model of coupled dark matter-dark energy from Λ cold dark matter cosmology using properties of cosmic voids. Identifying voids with the VIDE toolkit, we find no statistically significant differences in the ellipticities, but find that coupling produces a population of significantly larger voids, possibly explaining the recent result of Tavasoli et al. In addition, we use the universal density profile of Hamaus et al. to quantify the relationship between coupling and density profile shape, finding that the coupling produces broader, shallower, undercompensated profiles for large voids by thinning the walls between adjacent medium-scale voids. We find that these differences are potentially measurable with existing void catalogues once effects from survey geometries and peculiar velocities are taken into account.

  15. Structural control of void formation in dual phase steels

    DEFF Research Database (Denmark)

    Azuma, Masafumi

    The objective of this study is to explore the void formation mechanisms and to clarify the influence of the hardness and structural parameters (volume fraction, size and morphology) of martensite particles on the void formation and mechanical properties in dual phase steels composed of ferrite...... and (iii) strain localization. The critical strain for void formation depends on hardness of the martensite, but is independent of the volume fraction, shape, size and distribution of the martensite. The strain partitioning between the martensite and ferrite depends on the volume fraction and hardness...... of the martensite accelerates the void formation in the martensite by enlarging the size of voids both in the martensite and ferrite. It is suggested that controlling the hardness and structural parameters associated with the martensite particles such as morphology, size and volume fraction are the essential...

  16. Apparent molal volumes of HMT and TATD in aqueous solutions around the temperature of maximum density of water

    International Nuclear Information System (INIS)

    Clavijo Penagos, J.A.; Blanco, L.H.

    2012-01-01

    Highlights: ►V φ for HMT and TATD in aqueous solutions around the temperature of maximum density of water are reported. ► V φ is linear in m form m = 0.025 for all the aqueous solutions investigated. ► Variation of V ¯ 2 ∞ with T obeys a second grade polynomial trend. ► The solutes are classified as structure breakers according to Hepler’s criterion. - Abstract: Apparent molal volumes V φ have been determined from density measurements for several aqueous solutions of 1,3,5,7-tetraazatricyclo[3.3.1.1(3,7)]decane (HMT) and 1,3,6,8-tetraazatricyclo[4.4.1.1(3,8)]dodecane (TATD) at T = (275.15, 275.65, 276.15, 276.65, 277.15, 277.65 and 278.15) K as function of composition. The infinite dilution partial molar volumes of solutes in aqueous solution are evaluated through extrapolation. Interactions of the solutes with water are discussed in terms of the effect of the temperature on the volumetric properties and the structure of the solutes. The results are interpreted in terms of water structure-breaking or structure forming character of the solutes.

  17. Clinical evaluation of a simple uroflowmeter for categorization of maximum urinary flow rate

    Directory of Open Access Journals (Sweden)

    Simon Pridgeon

    2007-01-01

    Full Text Available Objective: To evaluate the accuracy and diagnostic usefulness of a disposable flowmeter consisting of a plastic funnel with a spout divided into three chambers. Materials and Methods: Men with lower urinary tract symptoms (LUTS voided sequentially into a standard flowmeter and the funnel device recording maximum flow rate (Q max and voided volume (V void . The device was precalibrated such that filling of the bottom, middle and top chambers categorized maximum input flows as 15 ml s -1 respectively. Subjects who agreed to use the funnel device at home obtained readings of flow category and V void twice daily for seven days. Results: A single office reading in 46 men using the device showed good agreement with standard measurement of Q max for V void > 150 ml (Kappa = 0.68. All 14 men whose void reached the top chamber had standard Q max > 15 ml s -1 (PPV = 100%, NPV = 72% whilst eight of 12 men whose void remained in the bottom chamber had standard Q max < 10 ml s -1 (PPV = 70%, NPV = 94%. During multiple home use by 14 men the device showed moderate repeatability (Kappa = 0.58 and correctly categorized Q max in comparison to standard measurement for 12 (87% men. Conclusions: This study suggests that the device has sufficient accuracy and reliability for initial flow rate assessment in men with LUTS. The device can provide a single measurement or alternatively multiple home measurements to categorize men with Q max < 15 ml s -1 .

  18. Use of Raman Spectroscopy and Delta Volume Growth from Void Collapse to Assess Overwrap Stress Gradients Compromising the Reliability of Large Kevlar/Epoxy COPVs

    Science.gov (United States)

    Kezirian, Michael T.; Phoenix, S. Leigh; Eldridge, Jeffrey I.

    2009-01-01

    Composite Overwrapped Pressure Vessels (COPVs) are frequently used for storing pressurized gases aboard spacecraft and aircraft when weight saving is desirable compared to all-metal versions. Failure mechanisms in fibrous COPVs and variability in lifetime can be very different from their metallic counterparts; in the former, catastrophic stress-rupture can occur with virtually no warning, whereas in latter, a leak before burst design philosophy can be implemented. Qualification and certification typically requires only one burst test on a production sample (possibly after several pressure cycles) and the vessel need only meet a design burst strength (the maximum operating pressure divided by a knockdown factor). Typically there is no requirement to assess variability in burst strength or lifetime, much less determine production and materials processing parameters important to control of such variability. Characterizing such variability and its source is crucial to models for calculating required reliability over a given lifetime (e.g. R = 0.9999 for 15 years). In this paper we present a case study of how lack of control of certain process parameters in COPV manufacturing can result in variations among vessels and between production runs that can greatly increase uncertainty and reduce reliability. The vessels considered are 40-inch ( NASA Glenn Research center, Cleveland, OH, 44135 29,500 in3 ) spherical COPVs with a 0.74 in. thick Kevlar49/epoxy overwrap and with a titanium liner of which 34 were originally produced. Two burst tests were eventually performed that unexpectedly differed by almost 5%, and were 10% lower than anticipated from burst tests on 26-inch sister vessels similar in every detail. A major observation from measurements made during proof testing (autofrettage) of the 40-inch vessels was that permanent volume growth from liner yielding varied by a factor of more than two (150 in3 to 360 in3 ), which suggests large differences in the residual

  19. Coolant Void Reactivity Analysis of CANDU Lattice

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jin Su; Lee, Hyun Suk; Tak, Tae Woo; Lee, Deok Jung [UNIST, Ulsan (Korea, Republic of)

    2016-05-15

    Models of CANDU-6 and ACR-700 fuel lattices were constructed for a single bundle and 2 by 2 checkerboard to understand the physics related to CVR. Also, a familiar four factor formula was used to predict the specific contributions to reactivity change in order to achieve an understanding of the physics issues related to the CVR. At the same time, because the situation of coolant voiding should bring about a change of neutron behavior, the spectral changes and neutron current were also analyzed. The models of the CANDU- 6 and ACR-700 fuel lattices were constructed using the Monte Carlo code MCNP6 using the ENDF/B-VII.0 continuous energy cross section library based on the specification from AECL. The CANDU fuel lattice was searched through sensitivity studies of each design parameter such as fuel enrichment, fuel pitch, and types of burnable absorber for obtaining better behavior in terms of CVR. Unlike the single channel coolant voiding, the ACR-700 bundle has a positive reactivity change upon 2x2 checkerboard coolant voiding. Because of the new path for neutron moderation, the neutrons from the voided channel move to the no-void channel where they lose energy and come back to the voided channel as thermal neutrons. This phenomenon causes the positive CVR when checkerboard voiding occurs. The sensitivity study revealed the effects of the moderator to fuel volume ratio, fuel enrichment, and burnable absorber on the CVR. A fuel bundle with low moderator to fuel volume ratio and high fuel enrichment can help achieve negative CVR.

  20. Positive void reactivity

    International Nuclear Information System (INIS)

    Diamond, D.J.

    1992-09-01

    This report is a review of some of the important aspects of the analysis of large loss-of-coolant accidents (LOCAs). One important aspect is the calculation of positive void reactivity. To study this subject the lattice physics codes used for void worth calculations and the coupled neutronic and thermal-hydraulic codes used for the transient analysis are reviewed. Also reviewed are the measurements used to help validate the codes. The application of these codes to large LOCAs is studied with attention focused on the uncertainty factor for the void worth used to bias the results. Another aspect of the subject dealt with in the report is the acceptance criteria that are applied. This includes the criterion for peak fuel enthalpy and the question of whether prompt criticality should also be a criterion. To study the former, fuel behavior measurements and calculations are reviewed. (Author) (49 refs., 2 figs., tab.)

  1. Void effects on BWR Doppler and void reactivity feedback

    International Nuclear Information System (INIS)

    Hsiang-Shou Cheng; Diamond, D.J.

    1978-01-01

    The significance of steam voids and control rods on the Doppler feedback in a gadolinia shimmed BWR is demonstrated. The importance of bypass voids when determining void feedback is also shown. Calculations were done using a point model, i.e., feedback was expressed in terms of reactivity coefficients which were determined for individual four-bundle configurations and then appropriately combined to yield reactor results. For overpower transients the inclusion of the void effect of control rods is to reduce Doppler feedback. For overpressurization transients the inclusion of the effect of bypass void wil increase the reactivity due to void collapse. (author)

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

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof

    of different material length parameters in a multi-parameter theory is studied, and it is shown that the important length parameter is the same as under purely hydrostatic loading. It is quantified how micron scale voids grow less rapidly than larger voids, and the implications of this in the overall strength...... of the material is emphasized. It is concluded that for cracked specimens not only the void volume fraction, but also the typical void size is of importance to the fracture strength of ductile materials....

  3. Stability of void lattices under irradiation: a kinetic model

    International Nuclear Information System (INIS)

    Benoist, P.; Martin, G.

    1975-01-01

    Voids are imbedded in a homogeneous medium where point defects are uniformly created and annihilated. As shown by a perturbation calculation, the proportion of the defects which are lost on the cavities goes through a maximum, when the voids are arranged on a translation lattice. If a void is displaced from its lattice site, its growth rate becomes anisotropic and is larger in the direction of the vacant site. The relative efficiency of BCC versus FCC void lattices for the capture of point defects is shown to depend on the relaxation length of the point defects in the surrounding medium. It is shown that the rate of energy dissipation in the crystal under irradiation is maximum when the voids are ordered on the appropriate lattice

  4. Stability of void lattices under irradiation: a kinetic model

    International Nuclear Information System (INIS)

    Benoist, P.; Martin, G.

    1975-01-01

    Voids are imbedded in a homogeneous medium where point defects are uniformly created and annihilated. As shown by a perturbation calculation, the proportion of the defects which are lost on the cavities goes through a maximum, when the voids are arranged on a translation lattice. If a void is displaced from its lattice site, its growth the rate becomes anisotropic and is larger in the direction of the vacant site. The relative efficiency of BCC versus FCC void lattices for the capture of point defects is shown to depend on the relaxation length of the point defects in the surrounding medium. It is shown that the rate of energy dissipation in the crystal under irradiation is maximum when the voids are ordered on the appropriate lattice [fr

  5. Morphological Segregation in the Surroundings of Cosmic Voids

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-09-01

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

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

    International Nuclear Information System (INIS)

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

    1982-01-01

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

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

    DEFF Research Database (Denmark)

    Tvergaard, Viggo; Niordson, Christian Frithiof

    2008-01-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

  9. Archaeology of Void Spaces

    Science.gov (United States)

    Look, Cory

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

  10. 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.

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

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    2015-01-01

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

  12. On the formation of voids in internal tin Nb$_{3}$Sn superconductors

    CERN Document Server

    Scheuerlein, C; Haibel, A

    2007-01-01

    In this article we describe three void growth mechanisms in Nb$_{3}$Sn strands of the internal tin design on the basis of combined synchrotron micro-tomography and x-ray diffraction measurements during in-situ heating cycles. Initially void growth is driven by a reduction of void surface area by void agglomeration. The main void volume increase is caused by density changes during the formation of Cu3Sn in the strand. Subsequent transformation of Cu-Sn intermetallics into the lower density a-bronze reduces the void volume again. Long lasting temperature ramps and isothermal holding steps can neither reduce the void volume nor improve the chemical strand homogeneity prior to the superconducting A15 phase nucleation and growth.

  13. Alignment of galaxy spins in the vicinity of voids

    International Nuclear Information System (INIS)

    Slosar, Anže; White, Martin

    2009-01-01

    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 and Pen to describe the strength of such an alignment, we find that c0.11(0.13) at 95% (99.7%) confidence limit within a context of a toy model that assumes a perfectly spherical voids with sharp boundaries

  14. Displacive stability of a void in a void lattice

    International Nuclear Information System (INIS)

    Brailsford, A.D.

    1977-01-01

    It has recently been suggested that the stability of the void-lattice structure in irradiated metals may be attributed to the effect of the overlapping of the point-defect diffusion fields associated with each void. It is shown here, however, that the effect is much too weak. When one void is displaced from its lattice site, the displacement is shown to relax to zero as proposed, but a conservative estimate indicates that the characteristic time is equivalent to an irradiation dose of the order of 300 displacements per atom which is generally much greater than the dose necessary for void-lattice formation

  15. Is abdominal wall contraction important for normal voiding in the female rat?

    Directory of Open Access Journals (Sweden)

    Boone Timothy B

    2007-03-01

    Full Text Available Abstract Background Normal voiding behavior in urethane-anesthetized rats includes contraction of the abdominal wall striated muscle, similar to the visceromotor response (VMR to noxious bladder distension. Normal rat voiding requires pulsatile release of urine from a pressurized bladder. The abdominal wall contraction accompanying urine flow may provide a necessary pressure increment for normal efficient pulsatile voiding. This study aimed to evaluate the occurrence and necessity of the voiding-associated abdominal wall activity in urethane-anesthetized female rats Methods A free-voiding model was designed to allow assessment of abdominal wall activity during voiding resulting from physiologic bladder filling, in the absence of bladder or urethral instrumentation. Physiologic diuresis was promoted by rapid intravascular hydration. Intercontraction interval (ICI, voided volumes and EMG activity of the rectus abdominis were quantified. The contribution of abdominal wall contraction to voiding was eliminated in a second group of rats by injecting botulinum-A (BTX, 5 U into each rectus abdominis to induce local paralysis. Uroflow parameters were compared between intact free-voiding and BTX-prepared animals. Results Abdominal wall response is present in free voiding. BTX preparation eliminated the voiding-associated EMG activity. Average per-void volume decreased from 1.8 ml to 1.1 ml (p Conclusion The voiding-associated abdominal wall response is a necessary component of normal voiding in urethane anesthetized female rats. As the proximal urethra may be the origin of the afferent signaling which results in the abdominal wall response, the importance of the bladder pressure increment due to this response may be in maintaining a normal duration intermittent pulsatile high frequency oscillatory (IPHFO/flow phase and thus efficient voiding. We propose the term Voiding-associated Abdominal Response (VAR for the physiologic voiding-associated EMG

  16. 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.

  17. Flux pinning by voids in surface-oxidized superconducting niobium and vanadium

    International Nuclear Information System (INIS)

    Meij, G.P. van der.

    1984-03-01

    The volume pinning force in several niobium and vanadium samples with voids is determined at various temperatures. Reasonable agreement is found with the collective pinning theory of Larkin and Ovchinnikov above the field of maximum pinning, if the flux line lattice is assumed to be amorphous in this region and if the elementary pinning force is calculated from the quasi-classical theory of Thuneberg, Kurkijaervi, and Rainer. Also some history and relaxation effects are studied in an alternating field. A qualitative explanation is given in terms of flux line dislocations, which reduce the shear strength of the flux line lattice. (Auth.)

  18. Three-dimensional core analysis on a super fast reactor with negative local void reactivity

    International Nuclear Information System (INIS)

    Cao Liangzhi; Oka, Yoshiaki; Ishiwatari, Yuki; Ikejiri, Satoshi

    2009-01-01

    Keeping negative void reactivity throughout the cycle life is one of the most important requirements for the design of a supercritical water-cooled fast reactor (super fast reactor). Previous conceptual design has negative overall void reactivity. But the local void reactivity, which is defined as the reactivity change when the coolant of one fuel assembly disappears, also needs to be kept negative throughout the cycle life because the super fast reactor is designed with closed fuel assemblies. The mechanism of the local void reactivity is theoretically analyzed from the neutrons balance point of view. Three-dimensional neutronics/thermal-hydraulic coupling calculation is employed to analyze the characteristics of the super fast reactor including the local void reactivity. Some configurations of the core are optimized to decrease the local void reactivity. A reference core is successfully designed with keeping both overall and local void reactivity negative. The maximum local void reactivity is less than -30 pcm

  19. Measurements of void fraction by an improved multi-channel conductance void meter

    International Nuclear Information System (INIS)

    Song, Chul-Hwa; Chung, Moon Ki; No, Hee Cheon

    1998-01-01

    An improved multi-channel Conductance Void Meter (CVM) was developed to measure a void fraction. Its measuring principle is basically based upon the differences of electrical conductance of a two-phase mixture due to the variation of void fraction around a sensor. The sensor is designed to be flush-mounted to the inner wall of the test section to avoid the flow disturbances. The signal processor with three channels is specially designed so as to minimize the inherent error due to the phase difference between channels. It is emphasized that the guard electrodes are electrically shielded in order not to affect the measurements of two-phase mixture conductance, but to make the electric fields evenly distributed in a measuring volume. Void fraction is measured for bubbly and slug flow regimes in a vertical air-water loop, and statistical signal processing techniques are applied to show that CVM has a good dynamic resolution which is required to investigate the structural developments of bubbly flow and the propagation of void waves in a flow channel. (author)

  20. Void consolidation during open-die forging for ultralarge rotor shafts. (1. Formulation of void-closing behavior)

    International Nuclear Information System (INIS)

    Ono, Shin-ichi; Minami, Katsuyuki; Ochiai, Tomoyuki; Iwadate, Tadao; Nakata, Shin-ichi.

    1995-01-01

    Open-die forging experiments using different die geometries under hot isothermal conditions and three-dimensional simulations using rigid-plastic finite-element method were performed to formulate a void-closing behavior using only two factors; the integral of hydrostatic stress and the equivalent strain. First, upsetting, side-upsetting and V-shape die cogging of several cylinders with a spherical void at the center are carried out and the information on the void volume reduction is obtained. Seconds, the same forgings, but without voids is treated numerically and the development of stress and strain at the location of voids is investigated. Then, by combining these results, and using regression analysis, it is found that the void volume reduction is expressed as a polynomial function of the two factors. When the polynomial function is used, various forging methods can be evaluated quantitatively in terms of void-closing behavior. Therefore it is beneficial to optimize the forging process for a large rotor shaft. (author)

  1. Cine MR imaging in mitral valve prolapse; Study on mitral regurgitation and left atrial volume

    Energy Technology Data Exchange (ETDEWEB)

    Kumai, Toshihiko [Chiba Univ. (Japan). School of Medicine

    1993-02-01

    This study was undertaken to assess the ability of cine MR imaging to evaluate the direction, timing, and severity of mitral regurgitation in patients with mitral valve prolapse (MVP). The population of this study was 33 patients with MVP diagnosed by two-dimensional echocardiography and 10 patients with rheumatic mitral valve disease (MSR) for comparison. 7 patients with MVP and 5 with MSR had atrial fibrillation and/or history of congestive heart failure as complications. Mitral regurgitation was graded for severity by color Doppler flow imaging in all patients. Direction and size of systolic flow void in the left atrium were analyzed by contiguous multilevel cine MR images and the maximum volumes of flow void and left atrium were measured. Although flow void was found at the center of the left atrium in most of MSR, it was often directed along the postero-caudal atrial wall in anterior leaflet prolapse and along the anterocranial atrial wall in posterior leaflet prolapse. In MVP, the maximum volume of flow void was often seen in late systole. The maximum volume of flow void and that of left atrium were significantly larger in patients with atrial fibrillation and/or history of congestive heart failure. The length and volume of flow void were increased with clinical severity and degree of regurgitation determined by color Doppler flow imaging. Thus cine MR imaging provides a useful means for detection and semiquantitative evaluation of mitral regurgitation in subjects with MVP. (author).

  2. 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......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)....

  3. 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......The shear and equi-biaxial straining responses of periodic voided single crystals are analysed using discrete dislocation plasticity and a continuum strain gradient crystal plasticity theory. In the discrete dislocation formulation, the dislocations are all of edge character and are modelled...... between predictions of the two formulations for all crystal types and void volume fractions considered when the material length scale in the non-local plasticity model is chosen to be 0.325 mu m (about 10 times the slip plane spacing in the discrete dislocation models)....

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

    International Nuclear Information System (INIS)

    Ross, Glenn; Vuorinen, Vesa; Paulasto-Kröckel, Mervi

    2016-01-01

    Void formation in the Cu−Sn system has been identified as a major reliability issue with small volume electronic interconnects. Voids form during the interdiffusion of electrochemically deposited Cu and Sn, with varying magnitude and density. Electroplating parameters include the electrolytic chemistry composition and the electroplating current density, all of which appear to effect the voiding characteristics of the Cu−Sn system. In addition, interfacial voiding affects the growth kinetics of the Cu_3Sn and Cu_6Sn_5 intermetallic compounds of the Cu−Sn system. The aim here is to present voiding data as a function of electroplating chemistry and current density over a duration (up to 72 h) of isothermal annealing at 423 K (150 °C). Voiding data includes the average interfacial void size and average void density. Voids sizes grew proportionally as a function of thermal annealing time, whereas the void density grew initially very quickly but tended to saturate at a fixed density. A morphological evolution analysis called the physicochemical approach is utilised to understand the processes that occur when a voided Cu/Cu_3Sn interface causes changes to the IMC phase growth. The method is used to simulate the intermetallic thickness growths' response to interfacial voiding. The Cu/Cu_3Sn interface acts as a Cu diffusion barrier disrupting the diffusion of Cu. This resulted in a reduction in the Cu_3Sn thickness and an accelerated growth rate of Cu_6Sn_5. - Highlights: • Average void size is proportional linearly to thermal annealing time. • Average void density grows initially very rapidly followed by saturation. • Voids located close to the Cu/Cu_3Sn interface affect IMC growth rates. • Voids act as a diffusion barrier inhibiting Cu diffusion towards Sn. • Voids located at the interface cause Cu_3Sn to be consumed by Cu_6Sn_5.

  5. Quantification of a maximum injection volume of CO2 to avert geomechanical perturbations using a compositional fluid flow reservoir simulator

    Science.gov (United States)

    Jung, Hojung; Singh, Gurpreet; Espinoza, D. Nicolas; Wheeler, Mary F.

    2018-02-01

    Subsurface CO2 injection and storage alters formation pressure. Changes of pore pressure may result in fault reactivation and hydraulic fracturing if the pressure exceeds the corresponding thresholds. Most simulation models predict such thresholds utilizing relatively homogeneous reservoir rock models and do not account for CO2 dissolution in the brine phase to calculate pore pressure evolution. This study presents an estimation of reservoir capacity in terms of allowable injection volume and rate utilizing the Frio CO2 injection site in the coast of the Gulf of Mexico as a case study. The work includes laboratory core testing, well-logging data analyses, and reservoir numerical simulation. We built a fine-scale reservoir model of the Frio pilot test in our in-house reservoir simulator IPARS (Integrated Parallel Accurate Reservoir Simulator). We first performed history matching of the pressure transient data of the Frio pilot test, and then used this history-matched reservoir model to investigate the effect of the CO2 dissolution into brine and predict the implications of larger CO2 injection volumes. Our simulation results -including CO2 dissolution- exhibited 33% lower pressure build-up relative to the simulation excluding dissolution. Capillary heterogeneity helps spread the CO2 plume and facilitate early breakthrough. Formation expansivity helps alleviate pore pressure build-up. Simulation results suggest that the injection schedule adopted during the actual pilot test very likely did not affect the mechanical integrity of the storage complex. Fault reactivation requires injection volumes of at least about sixty times larger than the actual injected volume at the same injection rate. Hydraulic fracturing necessitates much larger injection rates than the ones used in the Frio pilot test. Tested rock samples exhibit ductile deformation at in-situ effective stresses. Hence, we do not expect an increase of fault permeability in the Frio sand even in the presence of

  6. Local, zero-power void coefficient measurements in the ACPR

    Energy Technology Data Exchange (ETDEWEB)

    Rivard, J B; Thome, F V [Sandia Laboratories (United States)

    1974-07-01

    Changes in reactivity may be stimulated in the ACPR by the local introduction of voids into the reactor coolant. The local void coefficients of reactivity which describe this effect are of interest from a reactor safety point-of-view, and their determination is the subject of this presentation. Bottled nitrogen gas was used to produce the voids. The gas was forced out of a small diameter tube which was positioned vertically in the core lattice with its open end below the fuel. The gas was passed through a pressure regulator, a valve, and a flowmeter to establish a steady flow condition, following which a delayed-critical (zero-power) reactor state was established. Correlation of the average volume of core void created by the nitrogen flow with the reactivity worth of the delayed-critical control-rod bank position produced the values of the zero-power void coefficients of reactivity. The void coefficients were determined at various core positions from {approx}6 mm to 142 mm beyond the central irradiation space and for three different flow rates. For the range of void fractions investigated, these coefficients are negative, with values ranging between -$0.02 and -$0.12. Tabular and graphical results of the measurements are presented, and details of the coefficient determination are explained. (author)

  7. Local, zero-power void coefficient measurements in the ACPR

    International Nuclear Information System (INIS)

    Rivard, J.B.; Thome, F.V.

    1974-01-01

    Changes in reactivity may be stimulated in the ACPR by the local introduction of voids into the reactor coolant. The local void coefficients of reactivity which describe this effect are of interest from a reactor safety point-of-view, and their determination is the subject of this presentation. Bottled nitrogen gas was used to produce the voids. The gas was forced out of a small diameter tube which was positioned vertically in the core lattice with its open end below the fuel. The gas was passed through a pressure regulator, a valve, and a flowmeter to establish a steady flow condition, following which a delayed-critical (zero-power) reactor state was established. Correlation of the average volume of core void created by the nitrogen flow with the reactivity worth of the delayed-critical control-rod bank position produced the values of the zero-power void coefficients of reactivity. The void coefficients were determined at various core positions from ∼6 mm to 142 mm beyond the central irradiation space and for three different flow rates. For the range of void fractions investigated, these coefficients are negative, with values ranging between -$0.02 and -$0.12. Tabular and graphical results of the measurements are presented, and details of the coefficient determination are explained. (author)

  8. Maximum volume cuboids for arbitrarily shaped in-situ rock blocks as determined by discontinuity analysis—A genetic algorithm approach

    Science.gov (United States)

    Ülker, Erkan; Turanboy, Alparslan

    2009-07-01

    The block stone industry is one of the main commercial use of rock. The economic potential of any block quarry depends on the recovery rate, which is defined as the total volume of useful rough blocks extractable from a fixed rock volume in relation to the total volume of moved material. The natural fracture system, the rock type(s) and the extraction method used directly influence the recovery rate. The major aims of this study are to establish a theoretical framework for optimising the extraction process in marble quarries for a given fracture system, and for predicting the recovery rate of the excavated blocks. We have developed a new approach by taking into consideration only the fracture structure for maximum block recovery in block quarries. The complete model uses a linear approach based on basic geometric features of discontinuities for 3D models, a tree structure (TS) for individual investigation and finally a genetic algorithm (GA) for the obtained cuboid volume(s). We tested our new model in a selected marble quarry in the town of İscehisar (AFYONKARAHİSAR—TURKEY).

  9. PRECISION COSMOGRAPHY WITH STACKED VOIDS

    International Nuclear Information System (INIS)

    Lavaux, Guilhem; Wandelt, Benjamin D.

    2012-01-01

    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 redshift surveys. Our method is an Alcock-Paczyński (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.

  10. Air void clustering : [technical summary].

    Science.gov (United States)

    2015-06-01

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

  11. Post Operative Voiding Efficacy after Anterior Colporrhaphy

    Directory of Open Access Journals (Sweden)

    Behnoosh Miladpoor

    2010-02-01

    Full Text Available The aim of this study was to determine the most effective and suitable time to remove the urinary catheter (Foley after anterior and posterior colporrhaphy surgery. Patients who experience anterior Colporrhaphy operation for genuine stress incontinency or pelvic organ prolapsed will have post operative voiding dysfunction. These patients need postoperative drainage. One of the methods preferred for this purpose is to apply Foley Catheter, but there is no particular regimen available for the exact time of catheter removal in these patients. We have tried to find out the best time to remove Foley catheter after which the repeated Foley catheter is not required or minimized. One hundred and eighty nine patients who have been undergone Colporrhaphy have been selected randomly and divided into three groups' as 1, 2 and 4 days of catheter removal. The number of patients in each group was 62, 63 and 64 respectively. In all three groups, before removing urinary catheter, it was clamped every 4 hrs, for 3 times. After removing of Foley, the patients were guided for urination; the voiding and residual volume was measured. In the patients with an increase of residual volume, the  repeated Foley requirement was increased. However,  5.6 % of the patients with residual volume of ≤ 33 percent and 23.9% of the patients with residual volume between 33 to 68 percent, and finally  64.8% of the patients with residual volume of ≥ 68% had repeated Foley insertion. When considering the number of days, 85, 65 and 35.7 percent of the patients needed repeated Foley after 1, 2, and 4 days of catheter removal respectively. Interestingly, in the third group ( 4 days of the catheter removal with residual volume of ≤ 33% the repeated Foley requirement was nil, with no increase risk of urinary infection. We suggest that the best time to remove the urinary Foley catheter after anterior and posterior Colporrhaphy is the day four.

  12. A New Kind of Void Soap-free P(MMA-EA-MAA) Latex Particles

    Institute of Scientific and Technical Information of China (English)

    Kai KANG; Cheng You KAN; Yi DU; Yu Zhong LI; De Shan LIU

    2005-01-01

    Soap-free P(MMA-EA-MAA) particles with narrow size distribution were synthesized by seeded emulsion polymerization of methyl methacrylate (MMA), ethyl acrylate (EA) and methacrylic acid (MAA), and large voids inside the particles were generated by alkali posttreatment in the presence of 2-butanone. Results indicated that the size of void and the particle volume were related with the amount of 2-butanone. The generation mechanism of voids was proposed.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-02-15

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

  14. Effective void fraction for a BWR assembly with boiling in the bypass region

    International Nuclear Information System (INIS)

    Galperin, A.; Segev, M.; Knoglinger, E.

    1991-09-01

    Average BWR assembly cross-sections for nominal conditions, namely for zero bypass void, can be utilised in the analysis of transient conditions with boiling in the bypass. A model is developed to yield an effective channel void for such conditions. The use of this void in conjunction with the 'nominal conditions' cross section library approximately preserves the assembly K-infinity corresponding to the true channel and bypass voids. The effective void is an augmentation of the actual channel void. The augment is proportional to the bypass-to-channel volume ratio, to the bypass void, and to a weight W which is introduced to quantify the fact that a water molecule in the bypass has a different assembly criticality worth than one in the channel. The formula developed is superior to the practice of choosing W=1, namely a simple, non-weighted, transfer of water from channel to bypass. The use of this approximate effective channel void reproduces actual K-infinity values of assemblies to better than 5 mk, whereas the use of a simple model sometimes misspredicts the assembly K-infinity by 40 mK. The effective void model cannot handle cases in which both channel and bypass void value are high, simply because then the effective void α ch eff becomes meaningless. A method to treat the α eff >1 domain is developed by which corrections to cross sections are provided. Such corrections are synthesised as functions of the assembly parameters. (author) figs., tabs., refs

  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

  16. 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...

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

    International Nuclear Information System (INIS)

    Chung, H.M.

    2006-01-01

    hence, high swelling at EOL, especially in internal regions of small volume where irradiation temperature is high. However, it is considered unlikely that void swelling in a reentrant corner will exceed the threshold level of ∼4% beyond which the swelling rate reaches the steady state rate of 1%/dpa. However, this estimation is only preliminary, and a more accurate quantification of maximum temperature of reentrant corners at EOL and life-extension situations would be useful.

  18. Air void structure and frost resistance

    DEFF Research Database (Denmark)

    Hasholt, Marianne Tange

    2014-01-01

    ). This observation is interesting as the parameter of total surface area of air voids normally is not included in air void analysis. The following reason for the finding is suggested: In the air voids conditions are favourable for ice nucleation. When a capillary pore is connected to an air void, ice formation...... on that capillary pores are connected to air voids. The chance that a capillary pore is connected to an air void depends on the total surface area of air voids in the system, not the spacing factor.......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...

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

    KAUST Repository

    Liu, Jinxing

    2012-11-27

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

  20. Influence of the Metal Volume Fraction on the maximum deflection and impact load of GLARE plates subjected to low velocity impact

    Science.gov (United States)

    Bikakis, GSE; Savaidis, A.; Zalimidis, P.; Tsitos, S.

    2016-11-01

    Fiber-metal laminates are hybrid composite materials, consisting of alternating metal layers bonded to fiber-reinforced prepreg layers. GLARE (GLAss REinforced) belongs to this new family of materials. GLARE is the most successful fiber-metal laminate up to now and is currently being used for the construction of primary aerospace structures, such as the fuselage of the Airbus A380 air plane. Impact properties are very important in aerospace structures, since impact damage is caused by various sources, such as maintenance damage from dropped tools, collision between service cars or cargo and the structure, bird strikes and hail. The principal objective of this article is to evaluate the influence of the Metal Volume Fraction (MVF) on the low velocity impact response of GLARE fiber-metal laminates. Previously published differential equations of motion are employed for this purpose. The low velocity impact behavior of various circular GLARE plates is predicted and characteristic values of impact variables, which represent the impact phenomenon, are evaluated versus the corresponding MVF of the examined GLARE material grades. The considered GLARE plates are subjected to low velocity impact under identical impact conditions. A strong effect of the MVF on the maximum impact load and a significant effect on the maximum plate deflection of GLARE plates has been found.

  1. Finding Brazing Voids by Holography

    Science.gov (United States)

    Galluccio, R.

    1986-01-01

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

  2. Temperature effect on the inter-micellar collision and maximum packaging volume fraction in water/AOT/isooctane micro-emulsions

    International Nuclear Information System (INIS)

    Guettari, Moez; Ben Naceur, Imen; Kassab, Ghazi; Tajouri, Tahar

    2016-01-01

    We have studied the viscosity behaviour of water/AOT/isooctane micro-emulsions as a function of the volume fraction of the dispersed phase over a temperature range from the (298.15 to 328.15) K. For all the studied temperature range, a sharp increase of the viscosities is observed when the droplets concentration was varied. Several equations based on hard sphere model were examined to explain the behaviours of micro-emulsions under temperature and concentration effects. According to these equations, the shape factor and the inter-particle interaction parameters were found to be dependent on temperature which is in contradiction with experimental results reported in the literature. A modified Vand equation, taking into account the inter-particle collision time, is used to interpret the results obtained. This deviation is attributed to the aggregation of the droplets which becomes important by increasing temperature. The maximum packaging volume fraction of particles Φ_d_m and the intrinsic viscosity [η] were determined according to the Krieger and Dougherty equation through the temperature range studied. These two parameters were shown to be dependent on temperature but their product was found to be constant and close to 2 as reported in theory.

  3. Controlling Interfacial Separation in Porous Structures by Void Patterning

    Science.gov (United States)

    Ghareeb, Ahmed; Elbanna, Ahmed

    Manipulating interfacial response for enhanced adhesion or fracture resistance is a problem of great interest to scientists and engineers. In many natural materials and engineering applications, an interface exists between a porous structure and a substrate. A question that arises is how the void distribution in the bulk may affect the interfacial response and whether it is possible to alter the interfacial toughness without changing the surface physical chemistry. In this paper, we address this question by studying the effect of patterning voids on the interfacial-to-the overall response of an elastic plate glued to a rigid substrate by bilinear cohesive material. Different patterning categories are investigated; uniform, graded, and binary voids. Each case is subjected to upward displacement at the upper edge of the plate. We show that the peak force and maximum elongation at failure depend on the voids design and by changing the void size, alignment or gradation we may control these performance measures. We relate these changes in the measured force displacement response to energy release rate as a measure of interfacial toughness. We discuss the implications of our results on design of bulk heterogeneities for enhanced interfacial behavior.

  4. Spatial dependence of void coefficient in the University of Arizona TRIGA research reactor

    International Nuclear Information System (INIS)

    Spriggs, Gregory D.; Doane, Harry; Wells, Robert

    1980-01-01

    The spatial dependence of the moderator void coefficient of reactivity in the axial direction was experimentally measured in the A-ring using a hollow, air-filled aluminum cylinder. It was found that the void coefficient was positive in the central region of the fuel section reaching a maximum value of approximately + .045 cents/cm 3 and was negative towards the outer edges of the fuel section reaching a maximum of - .09 cents/cm 3 . (author)

  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. Analysis on void reactivity of DCA lattice

    International Nuclear Information System (INIS)

    Min, B. J.; Noh, K. H.; Choi, H. B.; Yang, M. K.

    2001-01-01

    In case of loss of coolant accident, the void reactivity of CANDU fuel provides the positive reactivity and increases the reactor power rapidly. Therefore, it is required to secure credibility of the void reactivity for the design and analysis of reactor, which motivated a study to assess the measurement data of void reactivity. The assessment of lattice code was performed with the experimental data of void reactivity at 30, 70, 87 and 100% of void fractions. The infinite multiplication factors increased in four types of fuels as the void fractions of them grow. The infinite multiplication factors of uranium fuels are almost within 1%, but those of Pu fuels are over 10% by the results of WIMS-AECL and MCNP-4B codes. Moreover, coolant void reactivity of the core loaded with plutonium fuel is more negative compared with that with uranium fuel because of spectrum hardening resulting from large void fraction

  7. Void migration in fusion materials

    International Nuclear Information System (INIS)

    Cottrell, G.A.

    2002-01-01

    Neutron irradiation in a fusion power plant will cause helium bubbles and voids to form in the armour and blanket structural materials. If sufficiently large densities of such defects accumulate on the grain boundaries of the materials, the strength and the lifetimes of the metals will be reduced by helium embrittlement and grain boundary failure. This Letter discusses void migration in metals, both by random Brownian motion and by biassed flow in temperature gradients. In the assumed five-year blanket replacement time of a fusion power plant, approximate calculations show that the metals most resilient to failure are tungsten and molybdenum, and marginally vanadium. Helium embrittlement and grain boundary failure is expected to be more severe in steel and beryllium

  8. Void migration in fusion materials

    Science.gov (United States)

    Cottrell, G. A.

    2002-04-01

    Neutron irradiation in a fusion power plant will cause helium bubbles and voids to form in the armour and blanket structural materials. If sufficiently large densities of such defects accumulate on the grain boundaries of the materials, the strength and the lifetimes of the metals will be reduced by helium embrittlement and grain boundary failure. This Letter discusses void migration in metals, both by random Brownian motion and by biassed flow in temperature gradients. In the assumed five-year blanket replacement time of a fusion power plant, approximate calculations show that the metals most resilient to failure are tungsten and molybdenum, and marginally vanadium. Helium embrittlement and grain boundary failure is expected to be more severe in steel and beryllium.

  9. Sodium voiding analysis in Kalimer

    International Nuclear Information System (INIS)

    Chang, Won-Pyo; Jeong, Kwan-Seong; Hahn, Dohee

    2001-01-01

    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)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-01-20

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

  11. Convex-based void filling method for CAD-based Monte Carlo geometry modeling

    International Nuclear Information System (INIS)

    Yu, Shengpeng; Cheng, Mengyun; Song, Jing; Long, Pengcheng; Hu, Liqin

    2015-01-01

    Highlights: • We present a new void filling method named CVF for CAD based MC geometry modeling. • We describe convex based void description based and quality-based space subdivision. • The results showed improvements provided by CVF for both modeling and MC calculation efficiency. - Abstract: CAD based automatic geometry modeling tools have been widely applied to generate Monte Carlo (MC) calculation geometry for complex systems according to CAD models. Automatic void filling is one of the main functions in the CAD based MC geometry modeling tools, because the void space between parts in CAD models is traditionally not modeled while MC codes such as MCNP need all the problem space to be described. A dedicated void filling method, named Convex-based Void Filling (CVF), is proposed in this study for efficient void filling and concise void descriptions. The method subdivides all the problem space into disjointed regions using Quality based Subdivision (QS) and describes the void space in each region with complementary descriptions of the convex volumes intersecting with that region. It has been implemented in SuperMC/MCAM, the Multiple-Physics Coupling Analysis Modeling Program, and tested on International Thermonuclear Experimental Reactor (ITER) Alite model. The results showed that the new method reduced both automatic modeling time and MC calculation time

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-08-25

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

  13. 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.

  14. 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.

  15. 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.

  16. Development of quick-response area-averaged void fraction meter

    International Nuclear Information System (INIS)

    Watanabe, Hironori; Iguchi, Tadashi; Kimura, Mamoru; Anoda, Yoshinari

    2000-11-01

    Authors are performing experiments to investigate BWR thermal-hydraulic instability under coupling of neutronics and thermal-hydraulics. To perform the experiment, it is necessary to measure instantaneously area-averaged void fraction in rod bundle under high temperature/high pressure gas-liquid two-phase flow condition. Since there were no void fraction meters suitable for these requirements, we newly developed a practical void fraction meter. The principle of the meter is based on the electrical conductance changing with void fraction in gas-liquid two-phase flow. In this meter, metal flow channel wall is used as one electrode and a L-shaped line electrode installed at the center of flow channel is used as the other electrode. This electrode arrangement makes possible instantaneous measurement of area-averaged void fraction even under the metal flow channel. We performed experiments with air/water two-phase flow to clarify the void fraction meter performance. Experimental results indicated that void fraction was approximated by α=1-I/I o , where α and I are void fraction and current (I o is current at α=0). This relation holds in the wide range of void fraction of 0∼70%. The difference between α and 1-I/I o was approximately 10% at maximum. The major reasons of the difference are a void distribution over measurement area and an electrical insulation of the center electrode by bubbles. The principle and structure of this void fraction meter are very basic and simple. Therefore, the meter can be applied to various fields on gas-liquid two-phase flow studies. (author)

  17. Severe Embrittlement of Neutron Irradiated Austenitic Steels Arising from High Void Swelling

    International Nuclear Information System (INIS)

    Neustroev, V.S.; Garner, F.

    2007-01-01

    Full text of publication follows: Data are presented from BOR-60 irradiations showing that significant radiation-induced swelling causes severe embrittlement in austenitic stainless steels, reducing the service life of structural components. Similar loss of ductility is expected when swelling arises in fusion and light water reactor environments. Above 7-16% swelling there is complete loss of ductility, with the onset of ductility loss beginning at lower swelling in ring-pull tensile tests than for flat tensile specimens. For steels that develop extensive precipitation during irradiation, the critical swelling level is even lower. A model is presented to demonstrate the effect of voids acting alone to produce the embrittlement. Although voids are not very effective hardeners, they are very effective to generate stress concentrations between voids. The stress concentration ratio increases strongly when the void diameter exceeds ∼40% of the void-to-void separation distance. When the volume fraction of voids is rather high (about 16 % and higher), a geometric situation develops where it is possible to create an intense field of deformation glide planes residing at an angle of 45 deg. to the void-to-void axis. Significant localized flow then proceeds on these planes for specimen stress levels that are significantly lower than the yield stress. Voids also segregate nickel to their surfaces such that flow localization occurs in the low-nickel inter-void regions to produce strain-induced martensite, which is further accelerated by stress concentrations at the advancing crack tip, leading to catastrophic failure. (authors)

  18. Development of the impedance void meter

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Moon Ki; Song, Chul Hwa; Won, Soon Yeon; Kim, Bok Deuk [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1994-06-01

    An impedance void meter is developed to measure the area-averaged void fraction. Its basic principle is based on the difference in the electrical conductivity between phases. Several methods of measuring void fraction are briefly reviewed and the reason why this type of void meter is chosen to develop is discussed. Basic principle of the measurement is thoroughly described and several design parameters to affect the overall function are discussed in detail. As example of applications is given for vertical air-water flow. It is shown that the current design has good dynamic response as well as very fine spatial resolution. (Author) 47 refs., 37 figs.

  19. Computer quantification of “angle of collapse” on maximum expiratory flow volume curve for diagnosing asthma-COPD overlap syndrome

    Directory of Open Access Journals (Sweden)

    Wang W

    2016-12-01

    Full Text Available Wei Wang, Mengshuang Xie, Shuang Dou, Liwei Cui, Wei Xiao Department of Pulmonary Medicine, Qilu Hospital, Shandong University, Jinan, People’s Republic of China Background: In a previous study, we demonstrated that asthma patients with signs of emphysema on quantitative computed tomography (CT fulfill the diagnosis of asthma-COPD overlap syndrome (ACOS. However, quantitative CT measurements of emphysema are not routinely available for patients with chronic airway disease, which limits their application. Spirometry was a widely used examination tool in clinical settings and shows emphysema as a sharp angle in the maximum expiratory flow volume (MEFV curve, called the “angle of collapse (AC”. The aim of this study was to investigate the value of the AC in the diagnosis of emphysema and ACOS. Methods: This study included 716 participants: 151 asthma patients, 173 COPD patients, and 392 normal control subjects. All the participants underwent pulmonary function tests. COPD and asthma patients also underwent quantitative CT measurements of emphysema. The AC was measured using computer models based on Matlab software. The value of the AC in the diagnosis of emphysema and ACOS was evaluated using receiver-operating characteristic (ROC curve analysis. Results: The AC of COPD patients was significantly lower than that of asthma patients and control subjects. The AC was significantly negatively correlated with emphysema index (EI; r=-0.666, P<0.001, and patients with high EI had a lower AC than those with low EI. The ROC curve analysis showed that the AC had higher diagnostic efficiency for high EI (area under the curve =0.876 than did other spirometry parameters. In asthma patients, using the AC ≤137° as a surrogate criterion for the diagnosis of ACOS, the sensitivity and specificity were 62.5% and 89.1%, respectively. Conclusion: The AC on the MEFV curve quantified by computer models correlates with the extent of emphysema. The AC may become a

  20. Visualization and void-fraction measurements in a molten metal bath

    Science.gov (United States)

    Baker, Michael Charles

    In the experimental study of multiphase flow phenomena, including intense multiphase interactions, such as vapor explosions, the fluids are often opaque. To obtain images, suitable for quantitative analysis, of such phenomena requires the use of something other than visible light, such as x-rays or neutrons. In this study a unique flow visualization technique using a continuous high energy x-ray source to measure void fraction with good spatial and temporal resolution in pools of liquid metal has been developed. In the present experiments, 11 to 21 kg of molten tin at 360sp° C to 425sp° C is collected in a pre-heated stainless steel test section of rectangular cross section (18 x 10 cm). In the base of the test section are two injection ports for the introduction of nitrogen gas and water. Each port is composed of two coaxial tubes. Nitrogen gas flows through the annular region and either nitrogen gas or water flows through the central tube. The test section is imaged using a high energy x-ray source (Varian Linatron 3000A) with a peak energy of 9 MeV and a maximum on axis dose rate of 30 Gy/min. The transmitted x-rays are viewed with an imaging system composed of a high density silicate glass screen, a mirror, a lens coupled image intensifier, and a CCD camera. Two interchangeable CCD cameras allow for either high resolution imaging (1128 x 480 pixels) at a frame rate of 30 Hz or low resolution imaging (256 x 256 pixels) at a frame rate of 220 Hz. The collected images are digitally processed to obtain the chordal averaged local and volume integral void fractions. At the experimental conditions examined, estimated relative uncertainty using this measurement technique is 10% for worst case conditions. The upper bound on the relative systematic error due to void dynamics is estimated to be 20%. Reasonable agreement has been demonstrated between the data generated from the processed images, past integral void fraction experimental data, and a semi-empirical drift

  1. A practical method for estimating maximum shear modulus of cemented sands using unconfined compressive strength

    Science.gov (United States)

    Choo, Hyunwook; Nam, Hongyeop; Lee, Woojin

    2017-12-01

    The composition of naturally cemented deposits is very complicated; thus, estimating the maximum shear modulus (Gmax, or shear modulus at very small strains) of cemented sands using the previous empirical formulas is very difficult. The purpose of this experimental investigation is to evaluate the effects of particle size and cement type on the Gmax and unconfined compressive strength (qucs) of cemented sands, with the ultimate goal of estimating Gmax of cemented sands using qucs. Two sands were artificially cemented using Portland cement or gypsum under varying cement contents (2%-9%) and relative densities (30%-80%). Unconfined compression tests and bender element tests were performed, and the results from previous studies of two cemented sands were incorporated in this study. The results of this study demonstrate that the effect of particle size on the qucs and Gmax of four cemented sands is insignificant, and the variation of qucs and Gmax can be captured by the ratio between volume of void and volume of cement. qucs and Gmax of sand cemented with Portland cement are greater than those of sand cemented with gypsum. However, the relationship between qucs and Gmax of the cemented sand is not affected by the void ratio, cement type and cement content, revealing that Gmax of the complex naturally cemented soils with unknown in-situ void ratio, cement type and cement content can be estimated using qucs.

  2. Studies of void formation in pure metals

    International Nuclear Information System (INIS)

    Lanore, J.M.; Glowinski, L.; Risbet, A.; Regnier, P.; Flament, J.L.; Levy, V.; Adda, Y.

    1975-01-01

    Recent experiments on the effect of gases on the final configuration of vacancy clustering (void or loop), and on the local effects at dislocations are described. The contribution of this data to a general knowledge of void formation will be discussed, and Monte Carlo calculations of swelling induced by irradiation with different particles presented [fr

  3. Void Fraction Instrument operation and maintenance manual

    International Nuclear Information System (INIS)

    Borgonovi, G.; Stokes, T.I.; Pearce, K.L.; Martin, J.D.; Gimera, M.; Graves, D.B.

    1994-09-01

    This Operations and Maintenance Manual (O ampersand MM) addresses riser installation, equipment and personnel hazards, operating instructions, calibration, maintenance, removal, and other pertinent information necessary to safely operate and store the Void Fraction Instrument. Final decontamination and decommissioning of the Void Fraction Instrument are not covered in this document

  4. Studies of void formation in pure metals

    International Nuclear Information System (INIS)

    Lanore, J.M.; Glowinski, L.; Risbet, A.; Regnier, P.; Flament, J.L.

    1975-01-01

    Recent experiments on the effect of gases on the final configuration of vacancy clustering (void or loop), and on the local effects at dislocations are described. The contribution of this data to our general knowledge of void formation will be discussed, and Monte Carlo calculations of swelling induced by irradiation with different particles presented

  5. Void formation in irradiated binary nickel alloys

    International Nuclear Information System (INIS)

    Shaikh, M.A.; Ahmed, M.; Akhter, J.I.

    1994-01-01

    In this work a computer program has been used to compute void radius, void density and swelling parameter for nickel and binary nickel-carbon alloys irradiated with nickel ions of 100 keV. The aim is to compare the computed results with experimental results already reported

  6. Pores and Void in Asclepiades’ Physical Theory

    Science.gov (United States)

    Leith, David

    2012-01-01

    This paper examines a fundamental, though relatively understudied, aspect of the physical theory of the physician Asclepiades of Bithynia, namely his doctrine of pores. My principal thesis is that this doctrine is dependent on a conception of void taken directly from Epicurean physics. The paper falls into two parts: the first half addresses the evidence for the presence of void in Asclepiades’ theory, and concludes that his conception of void was basically that of Epicurus; the second half focuses on the precise nature of Asclepiadean pores, and seeks to show that they represent void interstices between the primary particles of matter which are the constituents of the human body, and are thus exactly analogous to the void interstices between atoms within solid objects in Epicurus’ theory. PMID:22984299

  7. Lower limb muscle volume estimation from maximum cross-sectional area and muscle length in cerebral palsy and typically developing individuals.

    Science.gov (United States)

    Vanmechelen, Inti M; Shortland, Adam P; Noble, Jonathan J

    2018-01-01

    Deficits in muscle volume may be a significant contributor to physical disability in young people with cerebral palsy. However, 3D measurements of muscle volume using MRI or 3D ultrasound may be difficult to make routinely in the clinic. We wished to establish whether accurate estimates of muscle volume could be made from a combination of anatomical cross-sectional area and length measurements in samples of typically developing young people and young people with bilateral cerebral palsy. Lower limb MRI scans were obtained from the lower limbs of 21 individuals with cerebral palsy (14.7±3years, 17 male) and 23 typically developing individuals (16.8±3.3years, 16 male). The volume, length and anatomical cross-sectional area were estimated from six muscles of the left lower limb. Analysis of Covariance demonstrated that the relationship between the length*cross-sectional area and volume was not significantly different depending on the subject group. Linear regression analysis demonstrated that the product of anatomical cross-sectional area and length bore a strong and significant relationship to the measured muscle volume (R 2 values between 0.955 and 0.988) with low standard error of the estimates of 4.8 to 8.9%. This study demonstrates that muscle volume may be estimated accurately in typically developing individuals and individuals with cerebral palsy by a combination of anatomical cross-sectional area and muscle length. 2D ultrasound may be a convenient method of making these measurements routinely in the clinic. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Geotechnical reduction of void ratio in low-level radioactive waste burial sites: treatment alternatives

    International Nuclear Information System (INIS)

    Phillips, S.J.; Carlson, R.A.; McGuire, H.E.

    1981-01-01

    A substantial quantity of low-level radioactive and hazardous wastes has been interred in shallow land burial structures throughout the United States. Many of these structures (trenches, pits, and landfills) have proven to be unstable. Some surface feature manifestations such as large cracks, basins, and cave-ins are caused by voids filling and physico-chemical degradation and solubilization of the buried wastes which could result in the release of contamination. The surface features represent a potential for increased contamination transport to the biosphere via water, air, biologic, and direct pathways. Engineering alternatives for the reduction of buried waste and matrix materials voids are identified and discussed. As a guideline, a reduction of the voids within the waste to 80% or more of maximum relative dry density (a measure of in situ voids within the waste) is proposed. The advantages, disadvantages, and costs of each alternative are evaluated. Falling mass and pile driving engineering alternatives were selected for further development

  9. M-CHOLINOLYTICS IN RHEABILITATION OF CHILDREN WITH VOIDING DISFUNCTION AND URNARY BLADDER HYPERACTIVITY

    Directory of Open Access Journals (Sweden)

    I.V. Kazanskaya

    2006-01-01

    Full Text Available Voiding dysfunction is a common problem in pediatrics. Hyperactive urinary bladder is the most frequent cause of voiding dysfunction. Macholinolytic drugs are the first choice treatment for urinary bladder hyperactivity. The «urination pathology» center has investigated the efficacy of an macholinolytic, oxybutynin. The study included 25 children (aged 6–14 with different causes of voiding dysfunction and bladder hyperactivity. Oxybutynin was administered with a dosage of 5 mg twice a day, the follow up period was 8 weeks. The control evaluation of urodynamics (voiding rhythm, uroflowmetry, residual urine volume was performed at 4–8 weeks. Symptoms of bladder hyperactivity have been eliminated in 50% of patients, the bladder capacity has increased in 70% of cases, the frequency of night and day incontinence has diminished. The report demonstrates that oxybutynin has been most effective in patients with urinary bladder volume between 80 and 100 ml. the side effects, as dryness of mucous membranes and voiding difficulties, have been rarely observed. These side effects could be avoided by individual dose titration.Key words: voiding dysfunction, urinary bladder hyperactivity, oxybutynin, children.

  10. Electron microscopy observations of helium bubble-void transition effects in nimonic PE16 alloys

    International Nuclear Information System (INIS)

    Mazey, D.J.; Nelson, R.S.

    1980-01-01

    High-nickel alloys based on the Nimonic PE16 composition have been injected at temperatures of 525 0 C and 625 0 C with 1000 ppm helium to produce a high gas-bubble concentration and subsequently irradiated with 36 MeV nickel ions. Extensive heterogeneous nucleation of bubbles is observed on faulted interstitial loops and dislocations. Evidence is found in standard PE16 alloy for bimodal bubble plus void distributions which persist during nickel-ion irradiation to 30 and 60 dpa at 625 0 C and result in a low void volume swelling of approximately 1%. The observations can be correlated with the critical bubble/void transition radius which is calculated from theory to be approximately 4.4 nm. Pre-injection of helium into a 'matrix' PE16 (low Si, Ti and Al) alloy produced an initial bubble population whose average size was above the calculated transition radius such that all bubbles eventually grew as voids during subsequent nickel-ion irradiation up to 60 dpa at 625 0 C where the void volume swelling reached approximately 12%. The observations are discussed briefly and related to theoretical predictions of the bubble/void transition radius. (author)

  11. The sink strengths of voids and the expected swelling for both random and ordered void distributions

    International Nuclear Information System (INIS)

    Quigley, T.M.; Murphy, S.M.; Bullough, R.; Wood, M.H.

    1981-10-01

    The sink strength of a void has been obtained when the void is a member of a random or ordered distribution of voids. The former sink strength derivation has employed the embedding model and the latter the cellular model. In each case the spatially varying size-effect interaction between the intrinsic point defects and the voids has been included together with the presence of other sink types in addition to the voids. The results are compared with previously published sink strengths that have made use of an approximate representation for the size-effect interactions, and indicate the importance of using the exact form of the interaction. In particular the bias for interstitials compared with vacancies of small voids is now much reduced and contamination of the surfaces of such voids no longer appears essential to facilitate the nucleation and growth of the voids. These new sink strengths have been used, in conjunction with recently published dislocation sink strengths, to calculate the expected swelling of materials containing network dislocations and voids. Results are presented for both the random and the void lattice situations. (author)

  12. Estimation of the Void Fraction in the moderator cell of the Cold Neutron Source

    International Nuclear Information System (INIS)

    Choi, Jungwoon; Kim, Young-ki

    2015-01-01

    To estimate the average void fraction in the liquid hydrogen, the Kazimi and Chen correlation is used with its modified method suggested by R.E. Williams in NBSR. Since the multiplying number can be changed along the operation condition and working fluid, the different figure is applied to estimate the average void fraction in the different moderator cell shape. This approach is checked with the void fraction measurement results from the HANARO-CNS mock-up test. Owing to national research demands on cold neutron beam utilization, the Cold Neutron Research Facility had been and operated for neuron scientists all over the world. In HANARO, the CNS facility has been operated since 2009. The actual void fraction, which is the one of dominant factors affecting the cold neutron flux, is difficult to know without the real measurement performed at the cryogenic temperature using the same moderator medium. Accordingly, the two-phase mock-up test in the CNS-IPA (In-pool assembly) had been performed using the liquid hydrogen in terms of the fluidity check, void fraction measurement, operation procedure set-up, and so on for the development of the HANARO-CNS. This paper presents the estimated void fraction in the different operating conditions and geometrical shape in the comparison with the measurement data of the void fraction in the full-scale mockup test based on the Kazimi and Chen correlation. This approach is applied to estimate the average void fraction in the newly designed moderator cell using the liquid hydrogen as a working fluid in the two-phase thermosiphon. From this calculation result, the estimated average void fraction will be used to design the optimized cold neutron source to produce the maximum cold neutron flux within the desired wavelength

  13. Estimation of the Void Fraction in the moderator cell of the Cold Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jungwoon; Kim, Young-ki [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    To estimate the average void fraction in the liquid hydrogen, the Kazimi and Chen correlation is used with its modified method suggested by R.E. Williams in NBSR. Since the multiplying number can be changed along the operation condition and working fluid, the different figure is applied to estimate the average void fraction in the different moderator cell shape. This approach is checked with the void fraction measurement results from the HANARO-CNS mock-up test. Owing to national research demands on cold neutron beam utilization, the Cold Neutron Research Facility had been and operated for neuron scientists all over the world. In HANARO, the CNS facility has been operated since 2009. The actual void fraction, which is the one of dominant factors affecting the cold neutron flux, is difficult to know without the real measurement performed at the cryogenic temperature using the same moderator medium. Accordingly, the two-phase mock-up test in the CNS-IPA (In-pool assembly) had been performed using the liquid hydrogen in terms of the fluidity check, void fraction measurement, operation procedure set-up, and so on for the development of the HANARO-CNS. This paper presents the estimated void fraction in the different operating conditions and geometrical shape in the comparison with the measurement data of the void fraction in the full-scale mockup test based on the Kazimi and Chen correlation. This approach is applied to estimate the average void fraction in the newly designed moderator cell using the liquid hydrogen as a working fluid in the two-phase thermosiphon. From this calculation result, the estimated average void fraction will be used to design the optimized cold neutron source to produce the maximum cold neutron flux within the desired wavelength.

  14. An increased rectal maximum tolerable volume and long anal canal are associated with poor short-term response to biofeedback therapy for patients with anismus with decreased bowel frequency and normal colonic transit time.

    Science.gov (United States)

    Rhee, P L; Choi, M S; Kim, Y H; Son, H J; Kim, J J; Koh, K C; Paik, S W; Rhee, J C; Choi, K W

    2000-10-01

    Biofeedback is an effective therapy for a majority of patients with anismus. However, a significant proportion of patients still failed to respond to biofeedback, and little has been known about the factors that predict response to biofeedback. We evaluated the factors associated with poor response to biofeedback. Biofeedback therapy was offered to 45 patients with anismus with decreased bowel frequency (less than three times per week) and normal colonic transit time. Any differences in demographics, symptoms, and parameters of anorectal physiologic tests were sought between responders (in whom bowel frequency increased up to three times or more per week after biofeedback) and nonresponders (in whom bowel frequency remained less than three times per week). Thirty-one patients (68.9 percent) responded to biofeedback and 14 patients (31.1 percent) did not. Anal canal length was longer in nonresponders than in responders (4.53 +/- 0.5 vs. 4.08 +/- 0.56 cm; P = 0.02), and rectal maximum tolerable volume was larger in nonresponders than in responders. (361 +/- 87 vs. 302 +/- 69 ml; P = 0.02). Anal canal length and rectal maximum tolerable volume showed significant differences between responders and nonresponders on multivariate analysis (P = 0.027 and P = 0.034, respectively). This study showed that a long anal canal and increased rectal maximum tolerable volume are associated with poor short-term response to biofeedback for patients with anismus with decreased bowel frequency and normal colonic transit time.

  15. A variational constitutive model for the distribution and interactions of multi-sized voids

    KAUST Repository

    Liu, Jinxing

    2013-07-29

    The evolution of defects or voids, generally recognized as the basic failure mechanism in most metals and alloys, has been intensively studied. Most investigations have been limited to spatially periodic cases with non-random distributions of the radii of the voids. In this study, we use a new form of the incompressibility of the matrix to propose the formula for the volumetric plastic energy of a void inside a porous medium. As a consequence, we are able to account for the weakening effect of the surrounding voids and to propose a general model for the distribution and interactions of multi-sized voids. We found that the single parameter in classical Gurson-type models, namely void volume fraction is not sufficient for the model. The relative growth rates of voids of different sizes, which can in principle be obtained through physical or numerical experiments, are required. To demonstrate the feasibility of the model, we analyze two cases. The first case represents exactly the same assumption hidden in the classical Gurson\\'s model, while the second embodies the competitive mechanism due to void size differences despite in a much simpler manner than the general case. Coalescence is implemented by allowing an accelerated void growth after an empirical critical porosity in a way that is the same as the Gurson-Tvergaard-Needleman model. The constitutive model presented here is validated through good agreements with experimental data. Its capacity for reproducing realistic failure patterns is shown by simulating a tensile test on a notched round bar. © 2013 The Author(s).

  16. An approach of SFR safety study through the most penalizing sodium void reactivity - 105

    International Nuclear Information System (INIS)

    Tiberi, V.; Ivanov, E.; Pignet, S.

    2010-01-01

    Sodium void reactivity effects can affect the plant safety significantly during accidental transients. Accordingly, they have to be accurately investigated for any new sodium cooled fast reactor concept, even if a fuel with a melting point lower than the sodium boiling temperature is adopted. Thus all new reactor concepts should be compared to each - others adopting the value of the maximal possible sodium void reactivity as a discrimination parameter. However, taking into account that the sodium void worth is spatially depended, it is not evident which volume could be voided in order to obtain the maximal reactivity increase. Typically the complete active core voiding (zones initially loaded with 235 U or 239 Pu) is taken into account. This paper summarizes the extensive work carried-out in the IRSN to investigate the sodium-void reactivity spatial profiles of a fast sodium-cooled reactor core in the aim of defining a methodology to search for the area where the void contribution to the reactivity is strictly positive. Perturbation theory design approach available in the ERANOS 2.1 code has been adopted to evaluate the 'area of positive void worth'. To do that, the code has been previously validated against experimental based benchmarks (IRPhEP) and reference calculations. The evaluation of the absolute values of reactivity profiles can be improved later-on adopting more sophisticated methodologies to perform more accurate calculations of the sample with the voided area determined adopting the rough procedure described here. It has been demonstrated that even the non-reference way of ERANOS calculations could be used to provide the basis for different core concepts inter-comparison. (authors)

  17. Evaluation of the Air Void Analyzer

    Science.gov (United States)

    2013-07-01

    concrete using image analysis: Petrography of cementitious materials. ASTM STP 1215. S.M. DeHayes and D. Stark, eds. Philadelphia, PA: American...Administration (FHWA). 2006. Priority, market -ready technologies and innovations: Air Void Analyzer. Washington D.C. PDF file. Germann Instruments (GI). 2011...tests and properties of concrete and concrete-making materials. STP 169D. West Conshohocken, PA: ASTM International. Magura, D.D. 1996. Air void

  18. Development of gamma-ray densitometer and measurement of void fraction in instantaneous pipe rupture under BWR LOCA condition

    International Nuclear Information System (INIS)

    Yano, Toshikazu

    1983-11-01

    In order to clarify the transient mass flow rate under the instantaneous pipe rupture condition, it is necessary to use a highly sensitive void meter. Therefore, a high-response gamma-ray densitometer was developed for the measurement of void fraction variation caused by flashing vaporization of the high-pressure and -temperature water under the instantaneous pipe rupture accident. The measurement of void fraction was performed in the pipe rupture test under the BWR LOCA condition with a 6-inch diameter pipe. Initial conditions of the water were 6.86 MPa in pressure and the saturation temperature. To prove the reliability and accuracy, a calibration test by falling acrylic void simulators and an air injection test into cold water filled in the pipe were also conducted. The following results are obtained in the pipe rupture test. (1) The cone slit method is very useful to increase the measuring accuracy. (2) It is clearly observed that the apparent increase of void fraction occurs after the rarefaction wave passes. (3) The first maximum of void fraction occurs with some delay time after break. The following minimum void fraction concurs with the maximum pressure in the pressure recovering phenomena and with the maximum blowdown thrust force. (author)

  19. Using voids to unscreen modified gravity

    Science.gov (United States)

    Falck, Bridget; Koyama, Kazuya; Zhao, Gong-Bo; Cautun, Marius

    2018-04-01

    The Vainshtein mechanism, present in many models of gravity, is very effective at screening dark matter haloes such that the fifth force is negligible and general relativity is recovered within their Vainshtein radii. Vainshtein screening is independent of halo mass and environment, in contrast to e.g. chameleon screening, making it difficult to test. However, our previous studies have found that the dark matter particles in filaments, walls, and voids are not screened by the Vainshtein mechanism. We therefore investigate whether cosmic voids, identified as local density minima using a watershed technique, can be used to test models of gravity that exhibit Vainshtein screening. We measure density, velocity, and screening profiles of stacked voids in cosmological N-body simulations using both dark matter particles and dark matter haloes as tracers of the density field. We find that the voids are completely unscreened, and the tangential velocity and velocity dispersion profiles of stacked voids show a clear deviation from Λ cold dark matter at all radii. Voids have the potential to provide a powerful test of gravity on cosmological scales.

  20. Simulation of dust voids in complex plasmas

    Science.gov (United States)

    Goedheer, W. J.; Land, V.

    2008-12-01

    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 discharges in argon to study the behaviour of the void and the interaction between the dust and the plasma background. The model is based on a recently developed theory for the ion drag force and the charging of the dust. With this model, we studied the plasma inside the void and obtained an understanding of the way it is sustained by heat generated in the surrounding dust cloud. When this heating mechanism is suppressed by lowering the RF power, the plasma density inside the void decreases, even below the level where the void collapses, as was recently shown in experiments on board the International Space Station. In this paper we present results of simulations of this collapse. At reduced power levels the collapsed central cloud behaves as an electronegative plasma with corresponding low time-averaged electric fields. This enables the creation of relatively homogeneous Yukawa balls, containing more than 100 000 particles. On earth, thermophoresis can be used to balance gravity and obtain similar dust distributions.

  1. VizieR Online Data Catalog: SDSS DR7 voids and superclusters (Nadathur+, 2014)

    Science.gov (United States)

    Nadathur, S.; Hotchkiss, S.

    2016-02-01

    This is a public catalogue of voids and superclusters identified in the SDSS DR7 main galaxy and luminous red galaxy samples. This version is dated 04.11.2013. We make the catalogues available for general use. If you use them for your own work, we ask that you cite the original paper, Nadathur & Hotchkiss (2014MNRAS.440.1248N). The top-level directory cat_v11.11.13 contains an example python script called postproc.py, and two folders called comovcoords and redshiftcoords containing two versions of the catalogue in different coordinate systems. The comoving coordinate system is pretty self-explanatory, for a description of the other one please refer to the paper. Each of these directories is further divided into six folders containing the Type1 and Type2 void catalogues and the supercluster catalogue for each of the galaxy samples analysed here, and a folder called tools, which contains data useful for users wishing to apply their own selection criteria. The basic information provided includes the location of the barycentre of each structure, its volume, effective radius, average density and minimum or maximum density, its core galaxy and seed zone, the total number of galaxies in the seed zone, the number of zones merged to form the structure, the total number of particles in the structure, and its density ratio. These are split between two files for each structure type and each sample, named xxxinfo.txt and xxxlist.txt, where xxx refers to the structure type. It is also possible to extract lists of member galaxies of each structure and their magnitudes. An example python script, postproc.py, demonstrates how to access this information and how to build alternative catalogues using user-defined selection criteria. (27 data files).

  2. Medium term outcome of bipolar plasma vaporization in prostate cancer patients--a palliative modality of preserving spontaneous voiding.

    Science.gov (United States)

    Geavlete, B; Moldoveanu, C; Niţă, Gh; Stănescu, F; Jecu, M; Geavlete, P

    2012-12-15

    This retrospective analysis evaluated the efficiency, safety, and medium term postoperative results of bipolar plasma vaporization (BPV) in prostate cancer (PCa) cases associating complete urinary retention. A series of 40 patients diagnosed with locally advanced or metastatic PCa and complete urinary retention requiring a Foley catheter indwelling underwent BPV aiming to restore spontaneous voiding. A total of 35 patients completed the one year evaluation protocol consisting of International Prostate Symptom Score (IPSS), quality of life score (QoL), maximum flow rate (Q(max)) and post-voiding residual urinary volume (PVR), measured at 1, 3, 6 and 12 months after surgery. BPV was successfully performed in all cases with satisfactory efficiency, as confirmed by the mean operation time (42.8 minutes) and hemoglobin drop (0.7 g/dl). A fast and safe postoperative recovery period was described in this series (hematuria rate--7.5%; mean catheterization period--36 hours; mean hospital stay--2.5 days; early-irritative symptoms' rate--15%). At 1, 3, 6 and 12 months, satisfactory values were determined in terms of IPSS, Qmax, QoL and PVR. These parameters emphasized a stable evolution throughout the entire follow-up, as 88.6% of the patients maintained spontaneous voiding. The present trial confirmed the plasma-button vaporization as a promising therapeutic approach in PCa cases associating complete urinary retention. The technique displayed good efficacy, low perioperative morbidity, short convalescence, and satisfactory urodynamics and symptom score parameters during the one-year follow-up period.

  3. New insight on bubble-void transition effects in irradiated materials

    International Nuclear Information System (INIS)

    Dubinko, V.I.

    1993-01-01

    An account of elastic interaction between cavities and point defects is shown to result in new critical quantities for bubblevoid transition effects in irradiated cubic crystals. In contrast to previous theories, the present one gives not only critical quantities which determine the onset of bias-driven void swelling but the maximum stationary number density and the corresponding mean radius of voids as well as the duration of the bimodal regime. The void density and swelling rate are shown to be independent from the gas level. In the region of low temperatures/high dose rates, the void density appears to be independent from irradiation parameters as well. The relationships among material constants are found at which the stabilization of gas bubbles occurs via the dislocation loop punching mechanism resulting in a drastic change in the cavity behaviour under irradiation such as the saturation (or even suppression) of void swelling and void lattice formation. The theoretical results are compared with experimental data and further experimental tests are proposed. (author). 38 refs., 1 tab., 11 figs

  4. 38 CFR 3.207 - Void or annulled marriage.

    Science.gov (United States)

    2010-07-01

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

  5. Voiding dysfunction after abdominal radical hysterectomy. Comparison between patients with and without adjuvant irradiation therapy

    International Nuclear Information System (INIS)

    Ueda, Tomohiro; Yamauchi, Tamio; Kageyama, Susumu; Tsuzuki, Masahiro; Kawakami, Satoru; Yonese, Junji; Kawai, Tsuneo

    1994-01-01

    We evaluated 59 patients with voiding dysfunction after abdominal radical hysterectomy for uterine cancer. Of 59 patients, 45 underwent the surgery alone, and the other 14 underwent surgery and postoperative radiotherapy. Irradiation (mean dose, 60 Gy) was performed in bilateral commoni iliac regions excluding the bladder. In principle, the indwelling urethral catheter was removed 4 days after operation. All patients were followed up at the gynecologocal department until the onset of the voiding dysfunction. The mean interval between operation and the onset of voiding dysfunction was significantly longer (P<0.01) in the group treated by surgery alone (7.9 years) than in the group treated by surgery in combination with radiotherapy (3.8 year). Voiding dysfunction developed earlier as the age at the time of operation was higher. No differences were observed in the volume of residual urine, the detrusor function, or the incidence of urinary tract infection between the two groups. These results suggest that aged patients develop voiding dysfunction earlier after radical hysterectomy than young patients, and postoperative radiotherapy shortens the interval between operation and the onset of postoperative voiding dysfunction. (author)

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

    DEFF Research Database (Denmark)

    Holbøll, Joachim; Henriksen, Mogens

    1992-01-01

    /height analyses were performed over a period of 2400 h and showed very characteristic discharge patterns for each material combination. A unique behavior with regard to changes of pulse repetition rate and maximum apparent charge was observed for PD in alumina- and silica-filled epoxy. The void surfaces were...

  7. 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...

  8. Nucleation of voids - the impurity effect

    International Nuclear Information System (INIS)

    Chen, I-W; Taiwo, A.

    1984-01-01

    Nucleation of voids under irradiation in multicomponent alloys remains an unsolved theoretical problem. Of particular interest are the effects of nonequilibrium solute segregation phenomena on the critical nucleus and the nucleation rate. The resolution of the multicomponent nucleation in a dissipative system also has broader implication to the field of irreversible thermodynamics. The present paper describes a recent study of solute segregation effects in void nucleation. We begin with a thermodynamic model for a nonequilibrium void with interfacial segregation. The thermodynamic model is coupled with kinetic considerations of solute/solvent diffusion under a bias, which is itself related to segregation by the coating effect, to assess the stability of void embryos. To determine nucleation rate, we develop a novel technique by extending the most probable path method in statistical mechanics for nonequilibrium steady state to simulate large fluctuation with nonlinear dissipation. The path of nucleation is determined by solving an analogous problem on particle trajectory in classical dynamics. The results of both the stability analysis and the fluctuation analysis establish the paramount significance of the impurity effect via the mechanism of nonequilibrium segregation. We conclude that over-segregation is probably the most general cause for the apparently low nucleation barriers that are responsible for nearly ubiquitous occurrence of void swelling in common metals

  9. The Metallicity of Void Dwarf Galaxies

    Science.gov (United States)

    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 assumption that void galaxies are more pristine, we compare the evolutionary properties of a sample of dwarf galaxies selected specifically to lie in voids with a sample of similar isolated dwarf galaxies in average density environments. We measure gas-phase oxygen abundances and gas fractions for eight dwarf galaxies (Mr > -16.2), carefully selected to reside within the lowest density environments of seven voids, and apply the same calibrations to existing samples of isolated dwarf galaxies. We find no significant difference between these void dwarf galaxies and the isolated dwarf galaxies, suggesting that dwarf galaxy chemical evolution proceeds independent of the large-scale environment. While this sample is too small to draw strong conclusions, it suggests that external gas accretion is playing a limited role in the chemical evolution of these systems, and that this evolution is instead dominated mainly by the internal secular processes that are linking the simultaneous growth and enrichment of these galaxies.

  10. Video Voiding Device for Diagnosing Lower Urinary Tract Dysfunction in Men.

    Science.gov (United States)

    Shokoueinejad, Mehdi; Alkashgari, Rayan; Mosli, Hisham A; Alothmany, Nazeeh; Levin, Jacob M; Webster, John G

    2017-01-01

    We introduce a novel diagnostic Visual Voiding Device (VVD), which has the ability to visually document urinary voiding events and calculate key voiding parameters such as instantaneous flow rate. The observation of the urinary voiding process along with the instantaneous flow rate can be used to diagnose symptoms of Lower Urinary Tract Dysfunction (LUTD) and improve evaluation of LUTD treatments by providing subsequent follow-up documentations of voiding events after treatments. The VVD enables a patient to have a urinary voiding event in privacy while a urologist monitors, processes, and documents the event from a distance. The VVD consists of two orthogonal cameras which are used to visualize urine leakage from the urethral meatus, urine stream trajectory, and its break-up into droplets. A third, lower back camera monitors a funnel topped cylinder where urine accumulates that contains a floater for accurate readings regardless of the urine color. Software then processes the change in level of accumulating urine in the cylinder and the visual flow properties to calculate urological parameters. Video playback allows for reexamination of the voiding process. The proposed device was tested by integrating a mass flowmeter into the setup and simultaneously measuring the instantaneous flow rate of a predetermined voided volume in order to verify the accuracy of VVD compared to the mass flowmeter. The VVD and mass flowmeter were found to have an accuracy of ±2 and ±3% relative to full scale, respectively. A VVD clinical trial was conducted on 16 healthy male volunteers ages 23-65.

  11. X-ray Computed Tomography Assessment of Air Void Distribution in Concrete

    Science.gov (United States)

    Lu, Haizhu

    Air void size and spatial distribution have long been regarded as critical parameters in the frost resistance of concrete. In cement-based materials, entrained air void systems play an important role in performance as related to durability, permeability, and heat transfer. Many efforts have been made to measure air void parameters in a more efficient and reliable manner in the past several decades. Standardized measurement techniques based on optical microscopy and stereology on flat cut and polished surfaces are widely used in research as well as in quality assurance and quality control applications. Other more automated methods using image processing have also been utilized, but still starting from flat cut and polished surfaces. The emergence of X-ray computed tomography (CT) techniques provides the capability of capturing the inner microstructure of materials at the micrometer and nanometer scale. X-ray CT's less demanding sample preparation and capability to measure 3D distributions of air voids directly provide ample prospects for its wider use in air void characterization in cement-based materials. However, due to the huge number of air voids that can exist within a limited volume, errors can easily arise in the absence of a formalized data processing procedure. In this study, air void parameters in selected types of cement-based materials (lightweight concrete, structural concrete elements, pavements, and laboratory mortars) have been measured using micro X-ray CT. The focus of this study is to propose a unified procedure for processing the data and to provide solutions to deal with common problems that arise when measuring air void parameters: primarily the reliable segmentation of objects of interest, uncertainty estimation of measured parameters, and the comparison of competing segmentation parameters.

  12. 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

    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...... this shear failure mode boils down to the interaction between primary voids which rotate and elongate until coalescence occurs under severe plastic deformation of the internal ligaments. The objective of this paper is to analyze this failure mechanism of primary voids and to study the effect of smaller...... 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...

  13. Comparison of primary tumour volumes delineated on four-dimensional computed tomography maximum intensity projection and 18F-fluorodeoxyglucose positron emission tomography computed tomography images of non-small cell lung cancer

    International Nuclear Information System (INIS)

    Duan, Yili; Li, Jianbin; Zhang, Yingjie; Wang, Wei; Fan, Tingyong; Shao, Qian; Xu, Min; Guo, Yanluan; Sun, Xiaorong; Shang, Dongping

    2015-01-01

    The study aims to compare the positional and volumetric differences of tumour volumes based on the maximum intensity projection (MIP) of four-dimensional CT (4DCT) and 18 F-fluorodexyglucose ( 18 F-FDG) positron emission tomography CT (PET/CT) images for the primary tumour of non-small cell lung cancer (NSCLC). Ten patients with NSCLC underwent 4DCT and 18 F-FDG PET/CT scans of the thorax on the same day. Internal gross target volumes (IGTVs) of the primary tumours were contoured on the MIP images of 4DCT to generate IGTV MIP . Gross target volumes (GTVs) based on PET (GTV PET ) were determined with nine different threshold methods using the auto-contouring function. The differences in the volume, position, matching index (MI) and degree of inclusion (DI) of the GTV PET and IGTV MIP were investigated. In volume terms, GTV PET2.0 and GTV PET20% approximated closely to IGTV MIP with mean volume ratio of 0.93 ± 0.45 and 1.06 ± 0.43, respectively. The best MI was between IGTV MIP and GTV PET20% (0.45 ± 0.23). The best DI of IGTV MIP in GTV PET was IGTV MIP in GTV PET20% (0.61 ± 0.26). In 3D PET images, the GTVPET contoured by standardised uptake value (SUV) 2.0 or 20% of maximal SUV (SUV max ) approximate closely to the IGTV MIP in target size, while the spatial mismatch is apparent between them. Therefore, neither of them could replace IGTV MIP in spatial position and form. The advent of 4D PET/CT may improve the accuracy of contouring the perimeter for moving targets.

  14. Void growth suppression by dislocation impurity atmospheres

    International Nuclear Information System (INIS)

    Weertman, J.; Green, W.V.

    1976-01-01

    A detailed calculation is given of the effect of an impurity atmosphere on void growth under irradiation damage conditions. Norris has proposed that such an atmosphere can suppress void growth. The hydrostatic stress field of a dislocation that is surrounded by an impurity atmosphere was found and used to calculate the change in the effective radius of a dislocation line as a sink for interstitials and vacancies. The calculation of the impurity concentration in a Cottrell cloud takes into account the change in hydrostatic pressure produced by the presence of the cloud itself. It is found that void growth is eliminated whenever dislocations are surrounded by a condensed atmosphere of either oversized substitutional impurity atoms or interstitial impurity atoms. A condensed atmosphere will form whenever the average impurity concentration is larger than a critical concentration

  15. Comparative study of void fraction models

    International Nuclear Information System (INIS)

    Borges, R.C.; Freitas, R.L.

    1985-01-01

    Some models for the calculation of void fraction in water in sub-cooled boiling and saturated vertical upward flow with forced convection have been selected and compared with experimental results in the pressure range of 1 to 150 bar. In order to know the void fraction axial distribution it is necessary to determine the net generation of vapour and the fluid temperature distribution in the slightly sub-cooled boiling region. It was verified that the net generation of vapour was well represented by the Saha-Zuber model. The selected models for the void fraction calculation present adequate results but with a tendency to super-estimate the experimental results, in particular the homogeneous models. The drift flux model is recommended, followed by the Armand and Smith models. (F.E.) [pt

  16. From Voids to Yukawaballs And Back

    International Nuclear Information System (INIS)

    Land, V.; Goedheer, W. J.

    2008-01-01

    When dust particles are introduced in a radio-frequency discharge under micro-gravity conditions, usually a dust free void is formed due to the ion drag force pushing the particles away from the center. Experiments have shown that it is possible to close the void by reducing the power supplied to the discharge. This reduces the ion density and with that the ratio between the ion drag force and the opposing electric force. We have studied the behavior of a discharge with a large amount of dust particles (radius 3.4 micron) with our hydrodynamic model, and simulated the closure of the void for conditions similar to the experiment. We also approached the formation of a Yukawa ball from the other side, starting with a discharge at low power and injecting batches of dust, while increasing the power to prevent extinction of the discharge. Eventually the same situation could be reached.

  17. 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......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...

  18. Voids and overdensities of coupled Dark Energy

    International Nuclear Information System (INIS)

    Mainini, Roberto

    2009-01-01

    We investigate the clustering properties of dynamical Dark Energy even in association of a possible coupling between Dark Energy and Dark Matter. We find that within matter inhomogeneities, Dark Energy migth form voids as well as overdensity depending on how its background energy density evolves. Consequently and contrarily to what expected, Dark Energy fluctuations are found to be slightly suppressed if a coupling with Dark Matter is permitted. When considering density contrasts and scales typical of superclusters, voids and supervoids, perturbations amplitudes range from |δ φ | ∼ O(10 −6 ) to |δ φ | ∼ O(10 −4 ) indicating an almost homogeneous Dark Energy component

  19. Radar application in void and bar detection

    International Nuclear Information System (INIS)

    Amry Amin Abas; Mohamad Pauzi Ismail; Suhairy Sani

    2003-01-01

    Radar is one of the new non-destructive testing techniques for concrete and structures inspection. Radar is a non-ionizing electromagnetic wave that can penetrate deep into concrete or soil in about several tenths of meters. Method of inspection using radar enables us to perform high resolution detection, imaging and mapping of subsurface concrete and soil condition. This paper will discuss the use of radar for void and bar detection and sizing. The samples used in this paper are custom made samples and comparison will be made to validate the use of radar in detecting, locating and also size determination of voids and bars. (Author)

  20. Measurement of void fractions by nuclear techniques

    International Nuclear Information System (INIS)

    Hernandez G, A.; Vazquez G, J.; Diaz H, C.; Salinas R, G.A.

    1997-01-01

    In this work it is done a general analysis of those techniques used to determine void fractions and it is chosen a nuclear technique to be used in the heat transfer circuit of the Physics Department of the Basic Sciences Management. The used methods for the determination of void fractions are: radioactive absorption, acoustic techniques, average velocity measurement, electromagnetic flow measurement, optical methods, oscillating absorption, nuclear magnetic resonance, relation between pressure and flow oscillation, infrared absorption methods, sound neutron analysis. For the case of this work it will be treated about the radioactive absorption method which is based in the gamma rays absorption. (Author)

  1. Geometrical differences in target volumes based on 18F-fluorodeoxyglucose positron emission tomography/computed tomography and four-dimensional computed tomography maximum intensity projection images of primary thoracic esophageal cancer.

    Science.gov (United States)

    Guo, Y; Li, J; Wang, W; Zhang, Y; Wang, J; Duan, Y; Shang, D; Fu, Z

    2014-01-01

    The objective of the study was to compare geometrical differences of target volumes based on four-dimensional computed tomography (4DCT) maximum intensity projection (MIP) and 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) images of primary thoracic esophageal cancer for radiation treatment. Twenty-one patients with thoracic esophageal cancer sequentially underwent contrast-enhanced three-dimensional computed tomography (3DCT), 4DCT, and 18F-FDG PET/CT thoracic simulation scans during normal free breathing. The internal gross target volume defined as IGTVMIP was obtained by contouring on MIP images. The gross target volumes based on PET/CT images (GTVPET ) were determined with nine different standardized uptake value (SUV) thresholds and manual contouring: SUV≥2.0, 2.5, 3.0, 3.5 (SUVn); ≥20%, 25%, 30%, 35%, 40% of the maximum (percentages of SUVmax, SUVn%). The differences in volume ratio (VR), conformity index (CI), and degree of inclusion (DI) between IGTVMIP and GTVPET were investigated. The mean centroid distance between GTVPET and IGTVMIP ranged from 4.98 mm to 6.53 mm. The VR ranged from 0.37 to 1.34, being significantly (P<0.05) closest to 1 at SUV2.5 (0.94), SUV20% (1.07), or manual contouring (1.10). The mean CI ranged from 0.34 to 0.58, being significantly closest to 1 (P<0.05) at SUV2.0 (0.55), SUV2.5 (0.56), SUV20% (0.56), SUV25% (0.53), or manual contouring (0.58). The mean DI of GTVPET in IGTVMIP ranged from 0.61 to 0.91, and the mean DI of IGTVMIP in GTVPET ranged from 0.34 to 0.86. The SUV threshold setting of SUV2.5, SUV20% or manual contouring yields the best tumor VR and CI with internal-gross target volume contoured on MIP of 4DCT dataset, but 3DPET/CT and 4DCT MIP could not replace each other for motion encompassing target volume delineation for radiation treatment. © 2014 International Society for Diseases of the Esophagus.

  2. Friction stir welding process to repair voids in aluminum alloys

    Science.gov (United States)

    Rosen, Charles D. (Inventor); Litwinski, Edward (Inventor); Valdez, Juan M. (Inventor)

    1999-01-01

    The present invention provides an in-process method to repair voids in an aluminum alloy, particularly a friction stir weld in an aluminum alloy. For repairing a circular void or an in-process exit hole in a weld, the method includes the steps of fabricating filler material of the same composition or compatible with the parent material into a plug form to be fitted into the void, positioning the plug in the void, and friction stir welding over and through the plug. For repairing a longitudinal void (30), the method includes machining the void area to provide a trough (34) that subsumes the void, fabricating filler metal into a strip form (36) to be fitted into the trough, positioning the strip in the trough, and rewelding the void area by traversing a friction stir welding tool longitudinally through the strip. The method is also applicable for repairing welds made by a fusing welding process or voids in aluminum alloy workpieces themselves.

  3. Characterizing the effects of elevated temperature on the air void pore structure of advanced gas-cooled reactor pressure vessel concrete using x-ray computed tomography

    Directory of Open Access Journals (Sweden)

    Withers P.J.

    2013-07-01

    Full Text Available X-ray computed tomography (X-ray CT has been applied to nondestructively characterise changes in the microstructure of a concrete used in the pressure vessel structure of Advanced Gas-cooled Reactors (AGR in the UK. Concrete specimens were conditioned at temperatures of 105 °C and 250 °C, to simulate the maximum thermal load expected to occur during a loss of coolant accident (LOCA. Following thermal treatment, these specimens along with an unconditioned control sample were characterised using micro-focus X-ray CT with a spatial resolution of 14.6 microns. The results indicate that the air void pore structure of the specimens experienced significant volume changes as a result of the increasing temperature. The increase in the porous volume was more prevalent at 250 °C. Alterations in air void size distributions were characterized with respect to the unconditioned control specimen. These findings appear to correlate with changes in the uni-axial compressive strength of the conditioned concrete.

  4. Emission-line galaxies toward the booetes void

    International Nuclear Information System (INIS)

    Moody, J.W.

    1986-01-01

    Galaxies with strong emission are potentially useful as probes of the large-scale galaxian distribution. However, to serve as probes, their relative frequency and clustering properties must be known. This dissertation presents a study of these properties for field galaxies having [OIII] λ5007 emission equivalent widths greater than 10 A and reports on a search for galaxies with [OIII] λ5007 emission in the direction of the Booetes void, a volume located at α = 4/sup h/48/sup m/, δ = 47 0 , and cz = 15,000 km/sec that has been demonstrated to be under-abundant in galaxies by a factor of at least four. The study of field emission-line galaxies was done in two magnitude limited surveys consisting of 341 galaxies from both the north and south galactic caps having previously published redshifts and photometry. The galaxy spectra used for redshifts were examined and supplemented by new observations for 56 objects, primarily those with confirmed or suspected emission. Emission-line galaxies were found to comprise 8.8% of galaxies in a Illa-J selected sample or 6.6% of galaxies in a Illa-F selected sample. A search for emission-line galaxies towards the Booetes void was undertaken using the Burrell Schmidt telescope and an objective prism giving a reciprocal dispersion of 900 A/mm at Hβ. Three galaxies were found to lie within it, a result consistent with distributions through the void ranging from uniform to under-abundant by a factor of three

  5. Flux pinning by voids in surface-oxidized superconducting niobium and vanadium

    International Nuclear Information System (INIS)

    Meij, G.P. van der.

    1984-01-01

    This thesis describes a study of flux pinning by small voids (roughly 10 nm) in the type II superconductors niobium and vanadium. These voids were created in rectangular foils (with typical dimensions of 30x3x0.2 mm) during an irradiation with fast neutrons in the High Flux Reactor at Petten at temperatures between 400 and 1000 0 C. The pinning force per unit volume is determined from the magnetic properties of the superconducting samples. The experiments were carried out in a slowly ramped magnetic field, as well as in a combination of a static and a much smaller alternating field. (Auth.)

  6. Recurring priapism may be a symptom of voiding dysfunction – case report and literature review

    Directory of Open Access Journals (Sweden)

    Lisieux Eyer de Jesus

    2016-04-01

    Full Text Available ABSTRACT Recurring priapism is rare in pre-pubertal children and may be attributed to multiple causes. We propose that voiding dysfunction (VD may also justify this symptom and detail a clinical case of recurring stuttering priapism associated to overactive bladder that completely resolved after usage of anticholinergics and urotherapy. Sacral parasympathetic activity is responsible for detrusor contraction and for spontaneous erections and a relationship between erections and bladder status has been proved in healthy subjects (morning erections and models of medullar trauma. High bladder pressures and/or volumes, voiding incoordination and posterior urethritis can potentially trigger reflex erections.

  7. The Metallicity of Void Dwarf Galaxies

    NARCIS (Netherlands)

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

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

  8. "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.

  9. Void porosity measurements in coastal structures

    NARCIS (Netherlands)

    Bosma, C.; Verhagen, H.J.; D'Angremond, K.; Sint Nicolaas, W.

    2002-01-01

    The paper describes the use of two fundamental design parameters, the void porosity and layer thickness in rock armour constructions. These design parameters are very sensible for factors such as the boundary definition of a rock layer, rock production properties, intrinsic properties and

  10. 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...... dimensional array of spherical voids. It is shown that the high growth rate of very small voids predicted by conventional plasticity theory is not realistic when the effect of a characteristic length, dependent on the dislocation structure, is accounted for. (C) 2003 Elsevier Ltd. All rights reserved....

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-07-01

    Full text of publication follows: An obstacle in the development of oxide dispersion strengthened (ODS) steels for structural applications in fusion reactors is the toughness lack of the material produced by powder metallurgy and consolidated by hot isostatic pressing (HIP). In particular, ODS EUROFER steel with Y{sub 2}O{sub 3} particles appears to exhibit poor impact properties. To asses the capabilities of this material, it is necessary elucidate if its failure is an inherent characteristic of the production process that can not be mitigated by normalizing and tempering treatments. In order to investigate this particular point, the evolution of the structural defects retained in the ODS material during isochronal annealing has been probed by positron annihilation spectroscopy. The present study has been performed on bail milled EUROFER powders consolidated by HIP, containing 0.25 wt % Y{sub 2}O{sub 3} and without Y{sub 2}O{sub 3}. For comparison, un-milled EUROFER powder consolidated under identical conditions, and as-received EUROFER97 plate produced by Boehler AG have been also investigated. Samples from these four materials were isochronally annealed for 90 min up to 1323 K. Materials produced from milled powders had a longer positron lifetime than the one produced from un-milled powder or the EUROFER plate. In the material containing Y{sub 2}O{sub 3}, i.e. in ODS EUROFER, annealing above 723 K produced a continuous increase in the mean positron lifetime <{tau}> up to reach a maximum value of 208 ps after annealing at 1223 K. A similar annealing behavior was observed for Y{sub 2}O{sub 3}-free milled EUROFER (milled EUROFER), but the <{tau}> value steeply changed from {approx}160 ps at 823 K to {approx}200 ps after annealing at 1023 K. Subsequent anneals above this temperature produced meaningless changes in <{tau}>. The <{tau}> increase in milled EUROFER was accompanied by the intensity increase of a lifetime component of {approx}360 ps that is characteristic

  12. Modeling multiscale evolution of numerous voids in shocked brittle material.

    Science.gov (United States)

    Yu, Yin; Wang, Wenqiang; He, Hongliang; Lu, Tiecheng

    2014-04-01

    The influence of the evolution of numerous voids on macroscopic properties of materials is a multiscale problem that challenges computational research. A shock-wave compression model for brittle material, which can obtain both microscopic evolution and macroscopic shock properties, was developed using discrete element methods (lattice model). Using a model interaction-parameter-mapping procedure, qualitative features, as well as trends in the calculated shock-wave profiles, are shown to agree with experimental results. The shock wave splits into an elastic wave and a deformation wave in porous brittle materials, indicating significant shock plasticity. Void collapses in the deformation wave were the natural reason for volume shrinkage and deformation. However, media slippage and rotation deformations indicated by complex vortex patterns composed of relative velocity vectors were also confirmed as an important source of shock plasticity. With increasing pressure, the contribution from slippage deformation to the final plastic strain increased. Porosity was found to determine the amplitude of the elastic wave; porosity and shock stress together determine propagation speed of the deformation wave, as well as stress and strain on the final equilibrium state. Thus, shock behaviors of porous brittle material can be systematically designed for specific applications.

  13. Analysis of nocturia with 24-h urine volume, nocturnal urine volume, nocturnal bladder capacity and length of sleep duration: concept for effective treatment modality.

    Science.gov (United States)

    Udo, Yukihiro; Nakao, Masahiro; Honjo, Hisashi; Ukimura, Osamu; Kawauchi, Akihiro; Kitakoji, Hiroshi; Miki, Tsuneharu

    2011-03-01

    • To determine the relationship between the number of nocturia and 24-h urine volume, nocturnal urine volume, nocturnal bladder capacity and length of sleep duration as well as to assess the significance of these factors with respect to eliminating nocturnal voidings in individual patients with nocturia. • Among 532 participants who completed a 3-day bladder diary between April 2005 and December 2006, the diaries of 450 participants without 24-h polyuria were analyzed. • Clinical variables such as the number of daytime and night-time voids, 24-h urine volume, nocturnal polyuria index, daytime and night-time maximum voided volumes (MVV), night/day MVV ratio, sleep duration and proportion of night/day urine production rates were obtained from each diary. • Participants were classified into eight groups according to values of three factors: nocturnal MVV, proportion of night/day urine production rates and length of sleep duration. • Each group was divided into three subgroups: non-nocturics (number of nocturnal voidings is zero), mild nocturics (number of nocturnal voidings is one) and severe nocturics (number of nocturnal voidings is two or more). • The data from non-nocturics with three normal factors were regarded as the normal control and compared with the variables of the other subgroups using Dunnett's method. • Variables that form the basis of classifying participants into eight groups and corresponding to abnormal factors of each group were statistically significant in all the subgroups of each group. • Furthermore, a significantly increased 24-h urine volume was found in severe nocturics of the group with three normal factors. • A significantly decreased 24-h urine volume was found in non-nocturics of groups with nocturnal polyuria, decreased bladder capacity and both long sleep duration and nocturnal polyuria. • A significantly increased nocturnal MVV and night/day MVV ratio were shown in non-nocturics and mild nocturics of the groups

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

    Energy Technology Data Exchange (ETDEWEB)

    Nishikawa, Ryusuke; Nakao, Ken-ichi [Department of Mathematics and Physics, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka 558-8585 (Japan); Yoo, Chul-Moon, E-mail: ryusuke@sci.osaka-cu.ac.jp, E-mail: knakao@sci.osaka-cu.ac.jp, E-mail: yoo@gravity.phys.nagoya-u.ac.jp [Division of Particle and Astrophysical Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602 (Japan)

    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.

  15. Void fraction prediction in saturated flow boiling

    International Nuclear Information System (INIS)

    Francisco J Collado

    2005-01-01

    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 vertical and horizontal

  16. Tank SY-101 void fraction instrument functional design criteria

    International Nuclear Information System (INIS)

    McWethy, L.M.

    1994-01-01

    This document presents the functional design criteria for design, analysis, fabrication, testing, and installation of a void fraction instrument for Tank SY-101. This instrument will measure the void fraction in the waste in Tank SY-101 at various elevations

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

    Science.gov (United States)

    2013-07-01

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

  18. 非对称和不定椭圆问题的有限体积元方法的最大模估计%Maximum Norm Estimates for Finite Volume Element Method for Non-selfadjoint and Indefinite Elliptic Problems

    Institute of Scientific and Technical Information of China (English)

    毕春加

    2005-01-01

    In this paper, we establish the maximum norm estimates of the solutions of the finite volume element method (FVE) based on the P1 conforming element for the non-selfadjoint and indefinite elliptic problems.

  19. Results and applications in thermoelasticity of materials with voids

    Directory of Open Access Journals (Sweden)

    Michele Ciarletta

    1991-05-01

    Full Text Available We consider the linear theory of a thermoelastic porous solid in which the skeletal or matrix is a thermoelastic material and the interstices are void of material. We assume that the initial body is free from stresses. The concept of a distributed body asserts that the mass density at time t has the decomposition γν, where γ is the density of the matrix material and ν (0 In the first part, in order to derive some applications of the reciprocity theorem, we recall some results established by same authors in [3]. Then we obtain integral representations of the solution and prove that the solving of the boundary-initial value problem can be reduced to the solving of an associated uncoupled problem and to an integral equation for the volume fraction field.

  20. 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...

  1. Void probability scaling in hadron nucleus interactions

    International Nuclear Information System (INIS)

    Ghosh, Dipak; Deb, Argha; Bhattacharyya, Swarnapratim; Ghosh, Jayita; Bandyopadhyay, Prabhat; Das, Rupa; Mukherjee, Sima

    2002-01-01

    Heygi while investigating with the rapidity gap probability (that measures the chance of finding no particle in the pseudo-rapidity interval Δη) found that a scaling behavior in the rapidity gap probability has a close correspondence with the scaling of a void probability in galaxy correlation study. The main aim in this paper is to study the scaling behavior of the rapidity gap probability

  2. Application of gamma densitometer for measurement of void fraction in liquid hydrogen moderator of HANARO cold neutron source

    International Nuclear Information System (INIS)

    Kim, Myong-Seop; Choi, Jungwoon; Sun, Gwang-Min; Lee, Kye-Hong

    2009-01-01

    The void fraction in the liquid hydrogen used for the moderator of the HANARO cold neutron source (CNS) was measured by using a gamma densitometer technique. A mock-up of the HANARO CNS facility with an electric heating system as the heat source instead of radiations was constructed. The photon transmissions through the hydrogen moderator were simulated to search for an optimum experimental condition. From the simulation, it was confirmed that Am-241 was suitable for the measurement of the void fraction in the liquid hydrogen medium. A gamma densitometer using the Am-241 gamma-ray source was designed and installed at the mock-up of the CNS. The attenuation of 59.5 keV gamma-rays from the Am-241 through the hydrogen medium was measured by using an HPGe detector. The void fraction was determined using the amount of the gamma-ray attenuation. The void fractions in the hydrogen moderator were measured for stable thermo-siphon loops with several electric heat loads applied to the moderator cell of the CNS mock-up. The longitudinal distribution of the void fraction inside the moderator cell was also determined. The void fraction measured at a heat load of 720 W had values of 8-41% depending on the height from the bottom of the moderator cell. The overall void fraction was obtained by volume-weighted averaging of its longitudinal distribution. The void fraction at the nuclear heating power expected at the normal operation condition of the HANARO CNS facility was determined to be about 20%. The large uncertainty was expected in the void fraction determination by a gamma densitometer for the liquid hydrogen medium with the void fraction less than 10%. When the void fraction of the liquid hydrogen was near 20%, the uncertainty in the void fraction determination by using a gamma densitometer became relatively small, and it was regarded as an acceptable level. The measurements for the void fraction will be very useful for the design and operation of the HANARO CNS.

  3. Neutron gauging to detect voids in polyurethane

    International Nuclear Information System (INIS)

    Tsang, F.Y.; Alger, D.M.; Brugger, R.M.

    1978-01-01

    Thermal-neutron radiography and fast-neutron gauging measurements were made to evaluate the feasibility of detecting voids in a polyurethane block placed between steel plates. This sandwich of polyurethane and steel simulates the walls of a canister being designed to hold explosive devices. The polyurethane would act as a shock absorber in the canister. A large fabrication cost saving would result by casting the polyurethane, but a nondestructive testing (NDT) method is needed to determine the uniformity of the polyurethane fill. The radiography measurements used a beam of thermal neutrons, while the gauging used filtered beams of 24 keV and fission spectrum neutrons. For the 83-mm-thick polyurethane and 130-mm-thick steel matrix, the thermal-neutron radiography was able to detect only those voids equal to about one-half the polyurethane thickness. The gauging detected voids in the path of the neutron beam of a few millimetres thickness in seconds to minutes. The gauging is feasible as an NDT method for the canister application

  4. Transcutaneous sacral neurostimulation for irritative voiding dysfunction.

    Science.gov (United States)

    Walsh, I K; Johnston, R S; Keane, P F

    1999-01-01

    Patients with irritative voiding dysfunction are often unresponsive to standard clinical treatment. We evaluated the response of such individuals to transcutaneous electrical stimulation of the third sacral nerve. 32 patients with refractory irritative voiding dysfunction (31 female and 1 male; mean age 47 years) were recruited to the study. Ambulatory transcutaneous electrical neurostimulation was applied bilaterally to the third sacral dermatomes for 1 week. Symptoms of frequency, nocturia, urgency, and bladder pain were scored by each patient throughout and up to 6 months following treatment. The mean daytime frequency was reduced from 11.3 to 7.96 (p = 0.01). Nocturia episodes were reduced from a mean of 2.6 to 1.8 (p = 0.01). Urgency and bladder pain mean symptom scores were reduced from 5.97 to 4.89 and from 1.48 to 0.64, respectively. After stopping therapy, symptoms returned to pretreatment levels within 2 weeks in 40% of the patients and within 6 months in 100%. Three patients who continued with neurostimulation remained satisfied with this treatment modality at 6 months. Transcutaneous third sacral nerve stimulation may be an effective and noninvasive ambulatory technique for the treatment of patients with refractory irritative voiding dysfunction. Following an initial response, patients may successfully apply this treatment themselves to ensure long-term relief.

  5. Void fraction measurements using neutron radiography

    International Nuclear Information System (INIS)

    Glickstein, S.S.; Vance, W.H.; Joo, H.

    1992-01-01

    Real-time neutron radiography is being evaluated for studying the dynamic behavior of two phase flow and for measuring void fraction in vertical and inclined water ducts. This technique provides a unique means of visualizing the behavior of fluid flow inside thick metal enclosures. To simulate vapor conditions encountered in a fluid flow duct, an air-water flow system was constructed. Air was injected into the bottom of the duct at flow rates up to 0.47 I/s (1 cfm). The water flow rate was varied between 0--3.78 I/m (0--1 gpm). The experiments were performed at the Pennsylvania State University nuclear reactor facility using a real-time neutron radiography camera. With a thermal neutron flux on the order of 10 6 n/cm 2 /s directed through the thin duct dimension, the dynamic behavior of the air bubbles was clearly visible through 5 cm (2 in.) thick aluminum support plates placed on both sides of the duct wall. Image analysis techniques were employed to extract void fractions from the data which was recorded on videotape. This consisted of time averaging 256 video frames and measuring the gray level distribution throughout the region. The distribution of the measured void fraction across the duct was determined for various air/water mixtures. Details of the results of experiments for a variety of air and water flow conditions are presented

  6. Vesicoureteral reflux in children: comparison of contrast - enhanced voiding ultrasonography with radiographic voiding cystourethrography - preliminary report

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Chong Hyun; Kim, Hyun Joo; Goo, Hyun Woo; Kim, Hungy; Lee, Jung Joo; Kim, Ellen Ai-Rhan; Kim, Ki Soo; Park, Young Seo; Pi, Soo Young [Ulsan Univ. College of Medicine, Seoul (Korea, Republic of)

    2001-01-01

    To compared the usefullness of contrst-enhanced voiding ultrasonogrphy (US) with that of radiogrphic voiding cystourethrography (VCUG) for the diagnosis of vesicoureteral reflux (VUR) in children. Ninety-five kidney-ureter units of 47 patients referred for investigation of VUR underwent contrast -enhanced voiding US followed by radiographic VCUG. After baseline US examination of the urinaru tract, residual urine in the bladder was drained through an inserted Foley catheter and the bladder was gravityfilled at a height of 1 m with normal saline. A galactose-based, microbubble-containning echo-enhancing agent (Lvovist; Dchering, Berlin, Germany) was then administered. The amount of this was approximately 10% of bldder capacity, and VUR was diagnosed when microbubbles appeared in the ureter or pelvocalyceal system. Using radiographic VCUG as a reference point, the accuracy with which contrst-enhanced voiding US detected VUR was calcilated. In 87 of 95 kidney-ureter units (91.6%), the two methods showed similiar results regarding the diagnosis or exclusion of VUR, which was detected by both in 12 units, but by neither in 75. VUR was shown to occcur in a total of 20 units, but in eight of these by one method only. In two units, VUR detected by contrast-enhanced voiding US was was not demostarted by radiographic VCUG; in six units, the resverse was true. In the detection of VUR, contrast-enhanced voiding us showed a sensitivity of 66.7%, a sprcificity of 97.4%, a positive predictive value of 85.7%, and a negative predictive value of 92.6%. Contrst-enhanced voiding US is highly specific and has high positive and nagative predictive values; its sensitivity, however, is not sufficiently high. The modality appears to be a useful diagnostic tool for the detection of VUR without exposure to ionizing radiation, though to be certain of its value, more experience of its use its first required.

  7. Vesicoureteral reflux in children: comparison of contrast - enhanced voiding ultrasonography with radiographic voiding cystourethrography - preliminary report

    International Nuclear Information System (INIS)

    Yoon, Chong Hyun; Kim, Hyun Joo; Goo, Hyun Woo; Kim, Hungy; Lee, Jung Joo; Kim, Ellen Ai-Rhan; Kim, Ki Soo; Park, Young Seo; Pi, Soo Young

    2001-01-01

    To compared the usefullness of contrst-enhanced voiding ultrasonogrphy (US) with that of radiogrphic voiding cystourethrography (VCUG) for the diagnosis of vesicoureteral reflux (VUR) in children. Ninety-five kidney-ureter units of 47 patients referred for investigation of VUR underwent contrast -enhanced voiding US followed by radiographic VCUG. After baseline US examination of the urinaru tract, residual urine in the bladder was drained through an inserted Foley catheter and the bladder was gravityfilled at a height of 1 m with normal saline. A galactose-based, microbubble-containning echo-enhancing agent (Lvovist; Dchering, Berlin, Germany) was then administered. The amount of this was approximately 10% of bldder capacity, and VUR was diagnosed when microbubbles appeared in the ureter or pelvocalyceal system. Using radiographic VCUG as a reference point, the accuracy with which contrst-enhanced voiding US detected VUR was calcilated. In 87 of 95 kidney-ureter units (91.6%), the two methods showed similiar results regarding the diagnosis or exclusion of VUR, which was detected by both in 12 units, but by neither in 75. VUR was shown to occcur in a total of 20 units, but in eight of these by one method only. In two units, VUR detected by contrast-enhanced voiding US was was not demostarted by radiographic VCUG; in six units, the resverse was true. In the detection of VUR, contrast-enhanced voiding us showed a sensitivity of 66.7%, a sprcificity of 97.4%, a positive predictive value of 85.7%, and a negative predictive value of 92.6%. Contrst-enhanced voiding US is highly specific and has high positive and nagative predictive values; its sensitivity, however, is not sufficiently high. The modality appears to be a useful diagnostic tool for the detection of VUR without exposure to ionizing radiation, though to be certain of its value, more experience of its use its first required

  8. Cine MRI of the ascending aorta in the elderly with respect to the flow signal void and aortic valve morphology

    International Nuclear Information System (INIS)

    Nakayama, Masafumi; Kyomasu, Yoshinori; Suzuki, Yasuko; Mashima, Yasuoki; Tanno, Munehiko; Endo, Kazuo; Yamada, Hideo

    1990-01-01

    Cine flow MRI was performed on a 1.5 Tesla system to observe signal intensity of blood flow within the ascending aorta in the elderly who had no aortic stenosis and to determine frequency of the flow signal void. Coronal and sagittal imaging planes of the ascending aorta were obtained in 27 aged patients with no known cardiac diseases (14 men and 13 women, mean age of 76) and 7 young volunteers (7 men, mean age of 24), utilizing ECG-gating, GRASS (gradient-recalled acquisition in steady state), and a flow compensation sequence. The young volunteers presented little or no signal void within the ascending aorta. In 26 (96%) of the 27 aged patients, on the other hand, signal void was demonstrated in the blood flow distal to the aortic valve during systole. The maximum length of the signal void that was measured at 318∼632 msec after the R wave of ECG ranged from 33 to 97 mm. Conventional and Doppler echocardiography was used to evaluate motion and morphology of the aortic valve in 19 of the 27 aged patients. Eighteen of these 19 subjects had aortic signal void on cine MRI. Echocardiography showed sclerotic changes of the aortic valve (i.e., increased echogenicity of the cusps and/or commissure fusion) in 10 (53%) of the 19 subjects. The mean maximum length of the signal void in the 10 patients with aortic valve sclerosis was significantly greater than that in the 9 patients with echocardiographically normal valve (68 vs.45 mm, p<0.01). These results suggest that signal void of blood flow in the ascending aorta, which is recognized as one of the characteristic findings in patients with aortic stenosis, is not a specific feature for this disease but rather a commom one in the elderly particularly those with sclerotic changes of the aortic valve. However, the length of the signal void may distinguish between nonstenotic and stenotic aortic valves. (author)

  9. Shock loading and reactive flow modeling studies of void induced AP/AL/HTPB propellant

    Science.gov (United States)

    Miller, P. J.; Lindfors, A. J.

    1998-07-01

    The unreactive Hugoniot of a class 1.3 propellant has been investigated by shock compression experiments. The results are analyzed in terms of an ignition and growth reactive flow model using the DYNA2D hydrocode. The calculated shock ignition parameters of the model show a linear dependence on measured void volume which appears to reproduce the observed gauge records well. Shock waves were generated by impact in a 75 mm single stage powder gun. Manganin and PVDF pressure gauges provided pressure-time histories to 140 kbar. The propellants were of similar formulation differing only in AP particle size and the addition of a burn rate modifer (Fe2O3) from that of previous investigations. Results show neglible effect of AP particle size on shock response in contrast to the addition of Fe2O3 which appears to `stiffen' the unreactive Hugoniot and enhances significantly the reactive rates under shock. The unreactive Hugoniot, within experimental error, compares favorably to the solid AP Hugoniot. Shock experiments were performed on propellant samples strained to induce insitu voids. The material state was quantified by uniaxial tension dialatometry. The experimental records show a direct correlation between void volume (0 to 1.7%) and chemical reactivity behind the shock front. These results are discussed in terms of `hot spot' ignition resulting from the shock collapse of the voids.

  10. 3D DEM simulation and analysis of void fraction distribution in a pebble bed high temperature reactor

    International Nuclear Information System (INIS)

    Yang, Xingtuan; Gui, Nan; Tu, Jiyuan; Jiang, Shengyao

    2014-01-01

    Highlights: • We show a detailed analysis of void fraction (VF) in HTR-10 of China using DEM. • Radial distribution (RD) of VF is uniform in the core and oscillated near the wall. • Axial distribution (AD) is linearly varied along height due to effect of gravity. • Steady RD of VF in the conical base is Gaussian-like, larger than packing bed. • Joint linear and normal distribution of VF is analyzed and explained. - Abstract: The current work analyzes the radial and axial distributions of void fraction of a pebble bed high temperature reactor. A three-dimensional pebble bed corresponding to our test facility of pebble bed type gas-cooled high temperature reactor (HTR-10) in Tsinghua University is simulated via discrete element method, and the radial and axial void fraction profiles are calculated. It validates the oscillating characteristics of radial void fraction near the wall. Detailed calculations show the differences of void fraction profiles between the stationary packing bed and the dynamically discharging bed. Based on the vertically and circumferentially averaged radial distribution and horizontally averaged axial distribution of void fraction, a fully three-dimensional analytical distribution of void fraction throughout the bed is established. The results show the combined effects of gravity and void variation in the pebble bed caused by the pebble discharging. It indicates the linearly increased packing effect caused by gravity in the vertical (axial) direction and the normal distribution of void in the horizontal (radial) direction by pebble drainage. These two effects coexist in the conical base of the bed whereas only the former effect exists in the cylindrical volume of the bed

  11. 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.

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

    DEFF Research Database (Denmark)

    Klöcker, H.; Tvergaard, Viggo

    2000-01-01

    For metals deformed at elevated temperatures the growth of voids to coalescence is studied numerically. The voids are assumed to be present from the beginning of deformation, and the rate of deformation considered is so high that void growth is dominated by power law creep of the material, without...... any noticeable effect of surface diffusion. Axisymmetric unit cell model computations are used to study void growth in a material containing a periodic array of voids, and the onset of the coalescence process is defined as the stage where plastic flow localizes in the ligaments between neighbouring...... voids. The focus of the study is on various relatively high stress triaxialties. In order to represent the results in terms of a porous ductile material model a set of constitutive relations are used, which have been proposed for void growth in a material undergoing power law creep....

  13. Relationship between visual prostate score (VPSS and maximum flow rate (Qmax in men with urinary tract symptoms

    Directory of Open Access Journals (Sweden)

    Mazhar A. Memon

    2016-04-01

    Full Text Available ABSTRACT Objective: To evaluate correlation between visual prostate score (VPSS and maximum flow rate (Qmax in men with lower urinary tract symptoms. Material and Methods: This is a cross sectional study conducted at a university Hospital. Sixty-seven adult male patients>50 years of age were enrolled in the study after signing an informed consent. Qmax and voided volume recorded at uroflowmetry graph and at the same time VPSS were assessed. The education level was assessed in various defined groups. Pearson correlation coefficient was computed for VPSS and Qmax. Results: Mean age was 66.1±10.1 years (median 68. The mean voided volume on uroflowmetry was 268±160mL (median 208 and the mean Qmax was 9.6±4.96mLs/sec (median 9.0. The mean VPSS score was 11.4±2.72 (11.0. In the univariate linear regression analysis there was strong negative (Pearson's correlation between VPSS and Qmax (r=848, p<0.001. In the multiple linear regression analyses there was a significant correlation between VPSS and Qmax (β-http://www.blogapaixonadosporviagens.com.br/p/caribe.html after adjusting the effect of age, voided volume (V.V and level of education. Multiple linear regression analysis done for independent variables and results showed that there was no significant correlation between the VPSS and independent factors including age (p=0.27, LOE (p=0.941 and V.V (p=0.082. Conclusion: There is a significant negative correlation between VPSS and Qmax. The VPSS can be used in lieu of IPSS score. Men even with limited educational background can complete VPSS without assistance.

  14. Effect of Selective Prostaglandin E2 EP2 Receptor Agonist CP-533,536 on Voiding Efficiency in Rats with Midodrine-Induced Functional Urethral Obstruction.

    Science.gov (United States)

    Kurihara, Ryoko; Imazumi, Katsunori; Takamatsu, Hajime; Ishizu, Kenichiro; Yoshino, Taiji; Masuda, Noriyuki

    2016-05-01

    We investigated the effect of the selective prostaglandin E2 EP2 receptor agonist CP-533,536 on voiding efficiency in rats with midodrine-induced functional urethral obstruction. The effect of CP-533,536 (0.03-0.3 mg/kg, intravenous [i.v.]) on urethral perfusion pressure (UPP) was investigated in anesthetized rats pre-treated with midodrine (1 mg/kg, i.v.), which forms an active metabolite that acts as an α1 -adrenoceptor agonist. The effect of CP-533,536 (0.03-0.3 mg/kg, i.v.) on cystometric parameters was also investigated in anesthetized rats. In addition, the effect of CP-533,536 (0.03-0.3 mg/kg, i.v.) on residual urine volume (RV) and voiding efficiency (VE) was investigated in conscious rats treated with midodrine (1 mg/kg, i.v.). CP-533,536 dose-dependently decreased UPP elevated by midodrine in anesthetized rats. In contrast, CP-533,536 did not affect maximum voiding pressure, intercontraction interval, or intravesical threshold pressure. In conscious rats, midodrine (1 mg/kg, i.v.) markedly increased RV and reduced VE. CP-533,536 dose-dependently ameliorated increases in RV and decreases in VE induced by midodrine. These results suggest that a selective EP2 receptor agonist could ameliorate the elevation of RV and improve the reduction of VE in rats with functional urethral obstruction caused by stimulation of α1 -adrenoceptors. The mechanism of action might be not potentiation of bladder contraction but rather preferential relief of urethral constriction. © 2014 Wiley Publishing Asia Pty Ltd.

  15. IAEA sodium void reactivity benchmark calculations

    International Nuclear Information System (INIS)

    Hill, R.N.; Finck, P.J.

    1992-01-01

    In this paper, the IAEA-1 992 ''Benchmark Calculation of Sodium Void Reactivity Effect in Fast Reactor Core'' problem is evaluated. The proposed design is a large axially heterogeneous oxide-fueled fast reactor as described in Section 2; the core utilizes a sodium plenum above the core to enhance leakage effects. The calculation methods used in this benchmark evaluation are described in Section 3. In Section 4, the calculated core performance results for the benchmark reactor model are presented; and in Section 5, the influence of steel and interstitial sodium heterogeneity effects is estimated

  16. Patient dose reduction during voiding cystourethrography

    International Nuclear Information System (INIS)

    Ward, Valerie L.

    2006-01-01

    Voiding cystourethrography (VCUG) is a commonly performed examination in a pediatric uroradiology practice. This article contains suggestions on how the radiation dose to a child from VCUG can be made ''as low as reasonably achievable'' (ALARA). The pediatric radiologist should consider the appropriateness of the clinical indication before performing VCUG and utilize radiation exposure techniques and parameters during VCUG to reduce radiation exposure to a child. The medical physicist and fluoroscope manufacturer can also work together to optimize a pulsed-fluoroscopy unit and further reduce the radiation exposure. Laboratory and clinical research is necessary to investigate methods that reduce radiation exposures during VCUG, and current research is presented here. (orig.)

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

    KAUST Repository

    Liu, Junxian

    2014-09-25

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

  18. A NEW STATISTICAL PERSPECTIVE TO THE COSMIC VOID DISTRIBUTION

    International Nuclear Information System (INIS)

    Pycke, J-R; Russell, E.

    2016-01-01

    In this study, we obtain the size distribution of voids as a three-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 obtain here 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 to investigate 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 three-parameter log-normal distribution. In addition, we find that there may be a relation between the hierarchical formation, skewness, and kurtosis of the log-normal distribution for each catalog. We also show that the shape of the three-parameter distribution from the samples is strikingly similar to the galaxy log-normal mass distribution obtained from numerical studies. This similarity between void size and galaxy mass distributions may possibly indicate evidence of nonlinear mechanisms affecting both voids and galaxies, such as large-scale accretion and tidal effects. Considering the fact that in this study, all voids are generated by galaxy mocks and show hierarchical structures in different levels, it may be possible that the same nonlinear mechanisms of mass distribution affect the void size distribution.

  19. Comparative assessment of the area of sealer voids in single cone obturation done with mineral trioxide aggregate, epoxy resin, and zinc-oxide eugenol based sealers

    Directory of Open Access Journals (Sweden)

    Anisha Kumar

    2016-01-01

    Full Text Available Introduction: Voids in the sealer mass have the potential to allow leakage through obturation. They are more critical in single cone (SC obturation as the volume of sealer used in this obturation is larger when compared to other obturations. Aim: To compare the area of voids in mineral trioxide aggregate (MTA-based, resin-based, and zinc oxide-eugenol-based sealers when employed with SC obturation technique. Materials and Methods: Fifteen teeth were cleaned and shaped and divided into three groups for SC obturation using MTA Fillapex, AH26, and Pulpdent sealers, respectively. The obturated teeth were sectioned at apical, middle, and coronal third, and area of voids in the sealer was assessed using a stereomicroscope and digital images and image software. The results were statistically analyzed using SPSS software and Kruskal-Wallis and Mann-Whitney tests. Results: The three tested sealers showed voids in all the sections except MTA Fillapex, which was void free in apical and middle sections. There were significant differences between these sealers regarding their section wise area of voids (P < 0.05. Similarly, there were significant differences in their overall area of voids (P < 0.05 with MTA Fillapex showing significantly least area of voids followed by AH26. Conclusions: SC obturation with MTA Fillapex sealer, which showed void free apical and middle third sections, had significantly least area of voids in the sealer followed by the one with AH26 sealer, whereas SC obturation with Pulpdent sealer had significantly most area of voids.

  20. One dimensional motion of interstitial clusters and void growth in Ni and Ni alloys

    Science.gov (United States)

    Yoshiie, T.; Ishizaki, T.; Xu, Q.; Satoh, Y.; Kiritani, M.

    2002-12-01

    One dimensional (1-D) motion of interstitial clusters is important for the microstructural evolution in metals. In this paper, the effect of 2 at.% alloying with elements Si (volume size factor to Ni: -5.81%), Cu (7.18%), Ge (14.76%) and Sn (74.08%) in Ni on 1-D motion of interstitial clusters and void growth was studied. In neutron irradiated pure Ni, Ni-Cu and Ni-Ge, well developed dislocation networks and voids in the matrix, and no defects near grain boundaries were observed at 573 K to a dose of 0.4 dpa by transmission electron microscopy. No voids were formed and only interstitial type dislocation loops were observed near grain boundaries in Ni-Si and Ni-Sn. The reaction kinetics analysis which included the point defect flow into planar sink revealed the existence of 1-D motion of interstitial clusters in Ni, Ni-Cu and Ni-Ge, and lack of such motion in Ni-Si and Ni-Sn. In Ni-Sn and Ni-Si, the alloying elements will trap interstitial clusters and thereby reduce the cluster mobility, which lead to the reduction in void growth.

  1. An improved electrical-conductance sensor for void-fraction measurement in a horizontal pipe

    International Nuclear Information System (INIS)

    Ko, Min Seok; Jemg, Dong Wook; Kim, Sin; Lee, Bo An; Won, Woo Youn; Lee, Yeon Gun

    2015-01-01

    The electrical-impedance method has been widely used for void-fraction measurement in two-phase flow due to its many favorable features. In the impedance method, the response characteristics of the electrical signal heavily depend upon flow pattern, as well as phasic volume. Thus, information on the flow pattern should be given for reliable void-fraction measurement. This study proposes an improved electrical-conductance sensor composed of a three-electrode set of adjacent and opposite electrodes. In the proposed sensor, conductance readings are directly converted into the flow pattern through a specified criterion and are consecutively used to estimate the corresponding void fraction. Since the flow pattern and the void fraction are evaluated by reading conductance measurements, complexity of data processing can be significantly reduced and real-time information provided. Before actual applications, several numerical calculations are performed to optimize electrode and insulator sizes, and optimal design is verified by static experiments. Finally, the proposed sensor is applied for air-water two-phase flow in a horizontal loop with a 40-mm inner diameter and a 5-m length, and its measurement results are compared with those of a wire-mesh sensor

  2. The Effect of Void Shape on the Mechanical Properties of Rock

    International Nuclear Information System (INIS)

    D.O. Potyondy

    2006-01-01

    The bonded-particle model for rock (Potyondy and Cundall, 2004) represents rock by a dense packing of non-uniform-sized circular or spherical particles that are bonded together at their contact points and whose mechanical behavior is simulated by the distinct-element method using the two- and three-dimensional programs PFC2D and PFC3D. A bonded-particle model of lithophysal tuff has been used to study the effect of lithophysae (hollow, bubble-like voids) on the mechanical properties (Young's modulus and unconfined compressive strength) of this rock, and to quantify the variability of these properties. The model reproduces the failure mechanisms observed in the laboratory and exhibits a reduction of strength and modulus with increasing lithophysal volume fraction. The effect of void shape on mechanical properties is studied by inserting randomly distributed voids of simple shape (circle, triangle and star) and by inserting voids corresponding with lithophysal cavities identified in panel maps of the walls of a tunnel through this material. These studies address tunnel-stability issues associated with mechanical degradation of planned emplacement drifts at Yucca Mountain, which is the designated site for the proposed US high-level nuclear waste repository

  3. Effect of helium on void formation in nickel

    International Nuclear Information System (INIS)

    Brimhall, J.L.; Simonen, E.P.

    1977-01-01

    This study examines the influence of helium on void formation in self-ion irradiated nickel. Helium was injected either simultaneously with, or prior to, the self-ion bombardment. The void microstructure was characterized as a function of helium deposition rate and the total heavy-ion dose. In particular, at 575 0 C and 5 X 10 -3 displacements per atom per second the void density is found to be proportional to the helium deposition rate. The dose dependence of swelling is initially dominated by helium driven nucleation. The void density rapidly saturates after which swelling continues with increasing dose only from void growth. It is concluded that helium promotes void nucleation in nickel with either helium implantation technique, pre-injection or simultaneous injection. Qualitative differences, however, are recognized. (Auth.)

  4. Void migration, coalescence and swelling in fusion materials

    International Nuclear Information System (INIS)

    Cottrell, G.A.

    2003-01-01

    A recent analysis of the migration of voids and bubbles, produced in neutron irradiated fusion materials, is outlined. The migration, brought about by thermal hopping of atoms on the surface of a void, is normally a random Brownian motion but, in a temperature gradient, can be slightly biassed up the gradient. Two effects of such migrations are the transport of voids and trapped transmutation helium atoms to grain boundaries, where embrittlement may result; and the coalescence of migrating voids, which reduces the number of non-dislocation sites available for the capture of knock-on point defects and thereby enables the dislocation bias process to maintain void swelling. A selection of candidate fusion power plant armour and structural metals have been analysed. The metals most resistant to void migration and its effects are tungsten and molybdenum. Steel and beryllium are least so and vanadium is intermediate

  5. Dependence of calculated void reactivity on film-boiling representation

    International Nuclear Information System (INIS)

    Whitlock, J.; Garland, W.

    1992-01-01

    Partial voiding of a fuel channel can lead to complicated neutronic analysis, because of highly nonuniform spatial distributions. An investigation of the distribution dependence of void reactivity in a Canada deuterium uranium (CANDU) lattice, specifically in the regime of film boiling, was done. Although the core is not expected to be critical at the time of sheath dryout, this study augments current knowledge of void reactivity in this type of lattice

  6. Nucleation and growth of voids by radiation. Pt. 2

    International Nuclear Information System (INIS)

    Mayer, R.M.; Brown, L.M.

    1980-01-01

    The original model of Brown, Kelly and Mayer [1] for the nucleation of interstitial loops has been extended to take into account the following: (i) mobility of the vacancies, (ii) generation and migration of gas atoms during irradiation, (iii) nucleation and growth of voids, and (iv) vacancy emission from voids and clusters at high temperatures. Using chemicalrate equations, additional expressions are formulated for the nucleation and growth of vacancy loops and voids. (orig.)

  7. Dislocation and void segregation in copper during neutron irradiation

    DEFF Research Database (Denmark)

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

    1986-01-01

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

  8. Approximate maximum parsimony and ancestral maximum likelihood.

    Science.gov (United States)

    Alon, Noga; Chor, Benny; Pardi, Fabio; Rapoport, Anat

    2010-01-01

    We explore the maximum parsimony (MP) and ancestral maximum likelihood (AML) criteria in phylogenetic tree reconstruction. Both problems are NP-hard, so we seek approximate solutions. We formulate the two problems as Steiner tree problems under appropriate distances. The gist of our approach is the succinct characterization of Steiner trees for a small number of leaves for the two distances. This enables the use of known Steiner tree approximation algorithms. The approach leads to a 16/9 approximation ratio for AML and asymptotically to a 1.55 approximation ratio for MP.

  9. Void shrinkage in stainless steel during high energy electron irradiation

    International Nuclear Information System (INIS)

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

    1976-03-01

    During irradiation of thin foils of an austenitic stainless steel in a high voltage electron microscope, steadily growing voids have been observed to suddenly shrink and disappear at the irradiation temperature of 650 0 Cthe phenomenon has been observed in specimens both with and withoutimplanted helium. Possible mechanisms for void shrinkage during irradiation are considered. It is suggested that the dislocation-pipe-diffusion of vacancies from or of self-interstitial atoms to the voids can explain the shrinkage behaviour of voids observed during our experiments. (author)

  10. Maximum permissible dose

    International Nuclear Information System (INIS)

    Anon.

    1979-01-01

    This chapter presents a historic overview of the establishment of radiation guidelines by various national and international agencies. The use of maximum permissible dose and maximum permissible body burden limits to derive working standards is discussed

  11. Void fraction instrument acceptance test procedure

    International Nuclear Information System (INIS)

    Stokes, T.I.; Pearce, K.L.

    1994-01-01

    This document presents the results of the acceptance test for the mechanical and electrical features (not specifically addressed by the software ATP) of the void fraction instrument (VFI). Acceptance testing of the VFI, control console, and decontamination spray assembly was conducted in the 306E building high bay and area adjacent to the facility. The VFI was tested in the horizontal position supported in multiple locations on rolling tables. The control console was located next to the VFI pneumatic control assembly. The VFI system was operated exactly as is expected in the tank farm, with the following exceptions: power was provided from a building outlet and the VFI was horizontal. The testing described in this document verifies that the mechanical and electrical features are operating as designed and that the unit is ready for field service

  12. How to perform the perfect voiding cystourethrogram

    International Nuclear Information System (INIS)

    Agrawalla, Seema; Pearce, Rowena; Goodman, T.Robin

    2004-01-01

    The voiding cystourethrogram (VCUG) examination is a difficult investigation to perform and is a stressful experience for patients and their parents, as well as for the radiologists, technicians and paediatric radiology nurses involved in the examination. Despite the VCUG being one of the most commonly performed fluoroscopic procedures in paediatric radiology practice, there is no general consensus as to the best way to perform this investigation. This is particularly concerning when one considers the potentially high gonadal radiation dose children may receive. Because of this, we have undertaken a comprehensive literature review of various aspects of the test in order to determine the best way to perform the VCUG in modern paediatric radiology practice. (orig.)

  13. Dynamics of core voiding during boiloff experiments

    International Nuclear Information System (INIS)

    Analytis, G.T.; Aksan, S.N.; Stierli, F.; Yadigaroglu, G.

    1987-01-01

    A series of boiloff experiments were conducted at the EIR NEPTUN test facility with a bundle consisting of 37 PWR fuel rod simulators. The test section was filled with subcooled coolant and the power was turned on. After an initial heatup phase, coolant was expelled from the test section due to rapid vapor generation near the mid-plane where the power generation was highest. Gradual boiloff of the remaining water followed. It was found that the ''collapsed liquid level'' (CLL) and the rod temperature histories could be predicted well, provided the initial expulsion of the coolant was calculated correctly. The axial void fraction and enthalpy profiles calculated with TRAC-BD/MOD1 provided the information needed for understanding the importance of heat transfer to the coolant before the inception of vapor generation, and the sensitivity of the results to the interfacial friction correlation used

  14. Effect of metallurgical variables on void swelling

    International Nuclear Information System (INIS)

    Johnston, W.G.; Lauritzen, T.; Rosolowski, J.H.; Turkalo, A.M.

    1976-01-01

    The mechanism of void swelling is reviewed briefly and the anticipated effects of metallurgical variables are described. Experimental results showing the effects of metallurgical variables are reviewed, most of the work being done by simulation methods employing charged particle bombardments to simulate reactor damage. Although the early emphasis was on structural variables such as grain size, cold work and precipitates to control swelling, it now seems that the practical reduction of swelling will be achieved by modifying alloy composition. Void swelling is strongly influenced by the relative amounts of Fe, Cr, and Ni in an alloy; the amount of swelling can be varied by three orders of magnitude by changing the relative amounts of the three elements in an austenitic ternary alloy. The effect of composition on swelling of a simple ferritic alloy will also be described. The swelling of a simple austenitic alloy of Fe, Cr, and Ni can be reduced by certain minor element additions. The most effective swelling inhibitors are Si, Ti, Zr, and Nb, and combinations of Si and Ti are synergetic. Swelling reductions of two orders of magnitude have been achieved with combined additions. Predictions of swelling in commercial solid solution alloys are made on the basis of the present knowledge of the effects of major composition and minor element additions. The predictions agree with experimental results. For more complex commercial alloys, predictions are made for the effects on swelling of heat treatments that cause changes in matrix composition. In some cases, heat treatment is expected to change the peak swelling by more than a factor of ten, and to shift the peak swelling temperature by almost 100 0 C. Sensitivity of swelling to detailed matrix composition places emphasis on the need for developing understanding of the stability of structure and local composition in an irradiation environment

  15. National standard and code compliance for electrical equipment installed in hazardous locations for the void fraction instrument

    International Nuclear Information System (INIS)

    Bussell, J.H.; Martin, J.D.; Stokes, T.I.

    1994-01-01

    The hazardous area classification is evaluated and defined for the void fraction instrument (VFI). The void fraction instrument is an instrument that is used to measure gas bubble concentration in tank waste. It is a 18.3 meter (60-foot) long pipe with swivel sampling head. The assembly is lowered into tank waste via an available riser and waste sample is obtained. The sample is obtained and the sample chamber is pressurized from a fixed volume chamber. The pressure is then measured and then the VFI is moved to the next sample elevation

  16. Three-dimensional simulations of void collapse in energetic materials

    Science.gov (United States)

    Rai, Nirmal Kumar; Udaykumar, H. S.

    2018-03-01

    The collapse of voids in porous energetic materials leads to hot-spot formation and reaction initiation. This work advances the current knowledge of the dynamics of void collapse and hot-spot formation using 3D reactive void collapse simulations in HMX. Four different void shapes, i.e., sphere, cylinder, plate, and ellipsoid, are studied. For all four shapes, collapse generates complex three-dimensional (3D) baroclinic vortical structures. The hot spots are collocated with regions of intense vorticity. The differences in the vortical structures for the different void shapes are shown to significantly impact the relative sensitivity of the voids. Voids of high surface area generate hot spots of greater intensity; intricate, highly contorted vortical structures lead to hot spots of corresponding tortuosity and therefore enhanced growth rates of reaction fronts. In addition, all 3D voids are shown to be more sensitive than their two-dimensional (2D) counterparts. The results provide physical insights into hot-spot formation and growth and point to the limitations of 2D analyses of hot-spot formation.

  17. Void worths in subcritical cores cooled by lead-bismuth

    International Nuclear Information System (INIS)

    Wallenius, Janne; Tucek, Kamil; Gudowski, Waclaw

    2001-01-01

    The introduction lead-bismuth coolant in accelerator driven transmutation systems (ADS) was: good neutron economy (higher source efficiency); natural circulation possible (decay heat removal); synergy with spallation target (simplified coolant management); high temperature of boiling (larger overpower margin); smaller void worths (operation at higher k-values). This paper deals with different aspects of the void worths in JAERI ADS

  18. 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

  19. A variational void coalescence model for ductile metals

    KAUST Repository

    Siddiq, Amir; Arciniega, Roman; El Sayed, Tamer

    2011-01-01

    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

  20. Theory of void swelling, irradiation creep and growth

    International Nuclear Information System (INIS)

    Wood, M.H.; Bullough, R.; Hayns, M.R.

    Recent progress in our understanding of the fundamental mechanisms involved in swelling, creep and growth of materials subjected to irradiation is reviewed. The topics discussed are: the sink types and their strengths in the lossy continuum; swelling and void distribution analysis, including recent work on void nucleation; and, irradiation creep and growth of zirconium and zircaloy are taken as an example

  1. Void nucleation in spheroidized steels during tensile deformation

    International Nuclear Information System (INIS)

    Fisher, J.R. Jr.

    1980-04-01

    An investigation was conducted to determine the effects of various mechanical and material parameters on void formation at cementite particles in axisymmetric tensile specimens of spheroidized plain carbon steels. Desired microstructures for each of three steel types were obtained. Observations of void morphology with respect to various microstructural features were made using optical and scanning electron microscopy

  2. A 3D Printed Implantable Device for Voiding the Bladder Using Shape Memory Alloy (SMA) Actuators.

    Science.gov (United States)

    Hassani, Faezeh Arab; Peh, Wendy Yen Xian; Gammad, Gil Gerald Lasam; Mogan, Roshini Priya; Ng, Tze Kiat; Kuo, Tricia Li Chuen; Ng, Lay Guat; Luu, Percy; Yen, Shih-Cheng; Lee, Chengkuo

    2017-11-01

    Underactive bladder or detrusor underactivity (DU) is defined as a reduction of contraction strength or duration of the bladder wall. Despite the serious healthcare implications of DU, there are limited solutions for affected individuals. A flexible 3D printed implantable device driven by shape memory alloys (SMA) actuators is presented here for the first time to physically contract the bladder to restore voluntary control of the bladder for individuals suffering from DU. This approach is used initially in benchtop experiments with a rubber balloon acting as a model for the rat bladder to verify its potential for voiding, and that the operating temperatures are safe for the eventual implantation of the device in a rat. The device is then implanted and tested on an anesthetized rat, and a voiding volume of more than 8% is successfully achieved for the SMA-based device without any surgical intervention or drug injection to relax the external sphincter.

  3. Effect of Preoperative Low Maximal Flow Rate on Postoperative Voiding Trials after the Midurethral Sling Procedure in Women with Stress Urinary Incontinence.

    Science.gov (United States)

    Chae, Ji Y; Bae, Jae H; Lee, Jeong G; Park, Hong S; Moon, Du G; Oh, Mi M

    2017-06-02

    To evaluate the effects of preoperative low maximal flow rate (Qmax) on voiding trials after the midurethral sling (MUS) procedure in women with stress urinary incontinence (SUI). One hundred and sixty-eight women who underwent MUS procedure were enrolled. Preoperative free uroflowmetry was performed and patients were divided by Qmax. Low Qmax was defined as a Qmax under 15 mL/sec with voided volume at least 150 mL. Surgical results, failure of voiding trial, and postoperative uroflowmetry parameters were compared between the groups. Failure of voiding trial was defined by a PVR more than 100 mL on postoperative uroflowmetry. At the discharge day, there were 42 cases showing failure of voiding trial and 33 cases requiring CIC, but only one patient showed failure of voiding trial at 12 months postoperatively. Overall, 48 patients had preoperative low Qmax. Low Qmax group showed lower Qmax in all of postoperative uroflowmetry, but there were no significant differences in the rate of postoperative voiding trial failure or CIC. The low Qmax group was then divided into two groups according to the preoperative detrusor pressure at Qmax over and under 20 cmH 2 O in pressure flow study. Comparing the two groups, no significant differences were observed in the cure rate, voiding trial failure or CIC. Our results suggest that women with preoperative low Qmax experienced no definite unfavorable voiding problem from the MUS procedure compared to those with normal voiding function. MUS procedure may be regarded as a safe and successful procedure in SUI women with low Qmax. © 2017 John Wiley & Sons Australia, Ltd.

  4. Separation of nucleation and growth of voids during tensile deformation of a dual phase steel using synchrotron microtomography

    Energy Technology Data Exchange (ETDEWEB)

    Requena, Guillermo, E-mail: guillermo.requena@tuwien.ac.at [INSA-Lyon, MATEIS CNRS UMR5510, F-69621 Villeurbanne (France); Maire, Eric; Leguen, Claire [INSA-Lyon, MATEIS CNRS UMR5510, F-69621 Villeurbanne (France); Thuillier, Sandrine [LIMATB, Université de Bretagne-Sud, rue de Saint Maudé, BP 92116, 56321 Lorient Cedex (France)

    2014-01-01

    The damage evolution in a DP980 dual phase steel is followed in situ by synchrotron microtomography during tensile deformation focusing on the effect that the triaxiality, induced by different sample geometries, exerts on damage formation and damage evolution. The growth of existing voids is separated from the voids nucleated between consecutive deformation steps using three-dimensional image analysis. The experimental results are correlated with those obtained by finite element analysis using a Gurson–Tvergaard–Needleman framework with a Chu and Needleman formulation to introduce the effect of nucleation of cavities. A relatively simple way to determine the nucleation parameters is proposed based on the volume of nucleated voids obtained from the tomographies. The evolution of the total volume fraction of cavities obtained from the calculations shows a good agreement with the experiments for the notched samples and reflects the effect of triaxiality on damage. Contrarily to experiments, the calculated accumulated volume fraction of nucleated voids does not reflect the effect of triaxiality suggesting the necessity to implement this parameter in the nucleation model.

  5. Propagation of void fraction uncertainty measures in the RETRAN-3D simulation of the Peach Bottom turbine trip

    International Nuclear Information System (INIS)

    Vinai, Paolo; Macian-Juan, Rafael; Chawla, Rakesh

    2011-01-01

    The paper describes the propagation of void fraction uncertainty, as quantified by employing a novel methodology developed at Paul Scherrer Institut, in the RETRAN-3D simulation of the Peach Bottom turbine trip test. Since the transient considered is characterized by a strong coupling between thermal-hydraulics and neutronics, the accuracy in the void fraction model has a very important influence on the prediction of the power history and, in particular, of the maximum power reached. It has been shown that the objective measures used for the void fraction uncertainty, based on the direct comparison between experimental and predicted values extracted from a database of appropriate separate-effect tests, provides power uncertainty bands that are narrower and more realistic than those based, for example, on expert opinion. The applicability of such an approach to best estimate, nuclear power plant transient analysis has thus been demonstrated.

  6. Chronic prostatitis presenting with dysfunctional voiding and effects of pelvic floor biofeedback treatment.

    Science.gov (United States)

    He, Wei; Chen, Minfeng; Zu, Xiongbing; Li, Yuan; Ning, Keping; Qi, Lin

    2010-04-01

    To investigate the features of chronic prostatitis presenting with dysfunctional voiding (DV) and the effects of pelvic floor biofeedback (PFB). The study included 21 patients, diagnosed by having symptoms for > or =3 months, including urinary frequency and urgency, voiding difficulty, upper abdominal or perineal discomfort, and with a score of > or =1 on the first and second part of the National Institutes of Health Chronic Prostatitis Symptom Index (NIH-CPSI). Patients with bacterial prostatitis, urethritis, interstitial cystitis, urethral stricture and neurogenic bladder were excluded. All patients had a urodynamic examination, to assess the uroflow curve, maximum urinary flow rate (Q(max)), maximum detrusor pressure during the storage phase (P(det.max)), maximum urethral pressure (MUP) and the maximum urethral closure pressure (MUCP) were recorded. PFB was carried out in patients with non-neurogenic detrusor sphincter dyssynergia, and the effects evaluated after 10 weeks. Before and after PFB treatment the mean (sd) Q(max), P(det.max), MUP, MUCP were 8.2 (4.1) vs 15.1 (7.3) mL/s, 125.1 (75.3) vs 86.3 (54.2) cmH(2)O, 124.3 (23.3) vs 65.4 (23.0) cmH(2)O and 101.5 (43.6) vs 43.5 (16.7) cmH(2)O, all significantly different (P PFB had satisfactory short-term effects on these patients.

  7. In situ rheology and gas volume in Hanford double-shell waste tanks

    International Nuclear Information System (INIS)

    Stewart, C.W.; Alzheimer, J.M.; Brewster, M.E.; Chen, G.; Reid, H.C.; Shepard, C.L.; Terrones, G.; Mendoza, R.E.

    1996-09-01

    This report is a detailed characterization of gas retention and release in 6 Hanford DS waste tanks. The results came from the ball rheometer and void fraction instrument in (flammable gas watch list) tanks SY-101, SY-103, AW-101, AN-103, AN-104, and AN-105 are presented. Instrument operation and derivation of data reduction methods are presented. Gas retention and release information is summarized for each tank and includes tank fill history and instrumentation, waste configuration, gas release, void fraction distribution, gas volumes, rheology, and photographs of the waste column from extruded core samples. Potential peak burn pressure is computed as a function of gas release fraction to portray the 'hazard signature' of each tank. It is shown that two tanks remain well below the maximum allowable pressure, even if the entire gas content were released and ignited, and that none of the others present a hazard with their present gas release behavior

  8. Radionuclide voiding cystography in intrarenal reflux detection

    International Nuclear Information System (INIS)

    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

  9. Precise Void Fraction Measurement in Two-phase Flows Independent of the Flow Regime Using Gamma-ray Attenuation

    Directory of Open Access Journals (Sweden)

    E. Nazemi

    2016-02-01

    Full Text Available Void fraction is an important parameter in the oil industry. This quantity is necessary for volume rate measurement in multiphase flows. In this study, the void fraction percentage was estimated precisely, independent of the flow regime in gas–liquid two-phase flows by using γ-ray attenuation and a multilayer perceptron neural network. In all previous studies that implemented a multibeam γ-ray attenuation technique to determine void fraction independent of the flow regime in two-phase flows, three or more detectors were used while in this study just two NaI detectors were used. Using fewer detectors is of advantage in industrial nuclear gauges because of reduced expense and improved simplicity. In this work, an artificial neural network is also implemented to predict the void fraction percentage independent of the flow regime. To do this, a multilayer perceptron neural network is used for developing the artificial neural network model in MATLAB. The required data for training and testing the network in three different regimes (annular, stratified, and bubbly were obtained using an experimental setup. Using the technique developed in this work, void fraction percentages were predicted with mean relative error of <1.4%.

  10. Void fraction correlations analysis and their influence on heat transfer of helical double-pipe vertical evaporator

    International Nuclear Information System (INIS)

    Parrales, Arianna; Colorado, Dario; Huicochea, Armando; Díaz, Juan; Alfredo Hernández, J.

    2014-01-01

    Highlights: • 50 void fraction correlations were evaluated on heat transfer in vertical evaporators. • Two-phase flow model based on control volume formulation was used. • The drift flux parameter is common in all correlations with satisfactory results. - Abstract: An analysis of 50 void fraction correlations available in the literature was performed to describe two-phase flow mechanism inside two helical double-pipe vertical evaporators. The evaporators considered water as working fluid connected in countercurrent so the change of phase was carried out into the internal tube. The discretized equations of continuity, momentum and energy in each flow were coupled using an implicit step by step method. The selection of the void fraction correlations for the mathematical model was based on inclusion of some theoretical limits. The results of this analysis were compared with the experimental data in steady state for two different evaporators, obtaining good agreement in the evaporation process for only 7 void fraction correlations. The Armand and Massena correlation had a mean percentage error (MPE) of 3.08%, followed by Rouhanni and Axelsson I adquired MPE=3.16%, Chisholm and Armand obtained MPE=3.18%, Steiner as well as Rouhanni and Axelsson II with MPE=3.19%, Bestion reached MPE=3.20% and Flanigan presented MPE=3.21%. Furthermore, the experimental and simulated heat flux were acceptable (R 2 =0.939). Finally, the results showed that the drift flux parameter was important to evaluate the void fraction

  11. Efficacy and safety of solifenacin plus tamsulosin OCAS in men with voiding and storage lower urinary tract symptoms: results from a phase 2, dose-finding study (SATURN).

    Science.gov (United States)

    Van Kerrebroeck, Philip; Haab, François; Angulo, Javier C; Vik, Viktor; Katona, Ferenc; Garcia-Hernandez, Alberto; Klaver, Monique; Traudtner, Klaudia; Oelke, Matthias

    2013-09-01

    Storage symptoms are often undertreated in men with lower urinary tract symptoms (LUTS). To evaluate the combination of an antimuscarinic (solifenacin) with an α-blocker (tamsulosin) versus tamsulosin alone in the treatment of men with LUTS. A double-blind, 12-wk, phase 2 study in 937 men with LUTS (≥ 3 mo, total International Prostate Symptom Score [IPSS] ≥ 13, and maximum urinary flow rate 4.0-15.0 ml/s). Eight treatment groups: tamsulosin oral controlled absorption system (OCAS) 0.4 mg; solifenacin 3, 6, or 9 mg; solifenacin 3, 6 or 9 mg plus tamsulosin OCAS 0.4 mg; or placebo. The primary efficacy end point was change from baseline in total IPSS. Secondary end points included micturition diary and quality-of-life (QoL) parameters. Post hoc subgroup analyses were performed by severity of baseline storage symptoms, with statistical comparisons presented only for tamsulosin OCAS alone versus combination therapy, due to the small sample size of the solifenacin monotherapy and placebo subgroups. Combination therapy was associated with significant improvements in micturition frequency and voided volume versus tamsulosin OCAS alone in the total study population; improvements in total IPSS were not significant. Statistically significant improvements in urgency episodes, micturition frequency, total urgency score, voided volume, IPSS storage subscore, IPSS-QoL index, and Patient Perception of Bladder Condition were observed in a subpopulation of men with two or more urgency episodes per 24h (Patient Perception of Intensity of Urgency Scale grade 3 or 4) and eight or more micturitions per 24h at baseline (storage symptoms subgroup) with combination therapy versus tamsulosin OCAS alone (p ≤ 0.05 for the dose-response slope, all variables). Combination therapy was well tolerated, and adverse events were consistent with the safety profiles of both compounds. Solifenacin plus tamsulosin OCAS did not significantly improve IPSS in the total study population but offered

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

    International Nuclear Information System (INIS)

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

    2013-01-01

    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. (paper)

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

    Directory of Open Access Journals (Sweden)

    Hodges SJ

    2014-10-01

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

  14. A sharp interface model for void growth in irradiated materials

    Science.gov (United States)

    Hochrainer, Thomas; El-Azab, Anter

    2015-03-01

    A thermodynamic formalism for the interaction of point defects with free surfaces in single-component solids has been developed and applied to the problem of void growth by absorption of point defects in irradiated metals. This formalism consists of two parts, a detailed description of the dynamics of defects within the non-equilibrium thermodynamic frame, and the application of the second law of thermodynamics to provide closure relations for all kinetic equations. Enforcing the principle of non-negative entropy production showed that the description of the problem of void evolution under irradiation must include a relationship between the normal fluxes of defects into the void surface and the driving thermodynamic forces for the void surface motion; these thermodynamic forces are identified for both vacancies and interstitials and the relationships between these forces and the normal point defect fluxes are established using the concepts of transition state theory. The latter theory implies that the defect accommodation into the surface is a thermally activated process. Numerical examples are given to illustrate void growth dynamics in this new formalism and to investigate the effect of the surface energy barriers on void growth. Consequences for phase field models of void growth are discussed.

  15. On nonlinear excitation of voids in dusty plasmas

    International Nuclear Information System (INIS)

    Nebbat, E.; Annou, R.; Bharuthram, R.

    2007-01-01

    The void, which is a dust-free region inside the dust cloud in the plasma, results from a balance of the electrostatic force and the ion-drag force on a dust particulate that has numerous forms, some of which are based on models whereas others are driven from first principles. To explain the generation of voids, K. Avinash, A. Bhattacharjee, and S. Hu [Phys. Rev. Lett. 90, 075001 (2003)] proposed a time-dependent nonlinear model that describes the void as a result of an instability. We augment this model by incorporating the grain drift and reintroducing the velocity convective term as well as by replacing the modeled ion-drag force by a more accurate one. The analysis is conducted in a spherical configuration. It is revealed that the void formation is a threshold phenomenon, i.e., it depends on the grain size. Furthermore, the void possesses a sharp boundary beyond which the dust density decreases and may present a corrugated aspect. For big size grains, the use of both ion-drag forces leads to voids of the same dimension, though for grains of small sizes, the Avinash force drives voids of a higher dimension. The model shows good agreement with the experiment

  16. Void nucleation at elevated temperatures under cascade-damage irradiation

    International Nuclear Information System (INIS)

    Semenov, A.A.; Woo, C.H.

    2002-01-01

    The effects on void nucleation of fluctuations respectively due to the randomness of point-defect migratory jumps, the random generation of free point defects in discrete packages, and the fluctuating rate of vacancy emission from voids are considered. It was found that effects of the cascade-induced fluctuations are significant only at sufficiently high total sink strength. At lower sink strengths and elevated temperatures, the fluctuation in the rate of vacancy emission is the dominant factor. Application of the present theory to the void nucleation in annealed pure copper neutron-irradiated at elevated temperatures with doses of 10 -4 -10 -2 NRT dpa showed reasonable agreement between theory and experiment. This application also predicts correctly the temporal development of large-scale spatial heterogeneous microstructure during the void nucleation stage. Comparison between calculated and experimental void nucleation rates in neutron-irradiated molybdenum at temperatures where vacancy emission from voids is negligible showed reasonable agreement as well. It was clearly demonstrated that the athermal shrinkage of relatively large voids experimentally observable in molybdenum at such temperatures may be easily explained in the framework of the present theory

  17. Magnetic resonance voiding cystography in the diagnosis of vesicoureteral reflux: comparative study with voiding cystourethrography.

    Science.gov (United States)

    Lee, Sang Kwon; Chang, Yongmin; Park, Noh Hyuck; Kim, Young Hwan; Woo, Seongku

    2005-04-01

    To evaluate the feasibility of magnetic resonance voiding cystography (MRVC) compared with voiding cystourethrography (VCUG) for detecting and grading vesicoureteral reflux (VUR). MRVC was performed upon 20 children referred for investigation of reflux. Either coronal T1-weighted spin-echo (SE) or gradient-echo (GE) (fast multiplanar spoiled gradient-echo (FMPSPGR) or turbo fast low-angle-shot (FLASH)) images were obtained before and after transurethral administration of gadolinium solution, and immediately after voiding. The findings of MRVC were compared with those of VCUG and technetium-99m ((99m)Tc) dimercaptosuccinic acid (DMSA) single-photon emission computed tomography (SPECT) performed within 6 months of MRVC. VUR was detected in 23 ureterorenal units (16 VURs by both methods, 5 VURs by VCUG, and 2 VURs by MRVC). With VCUG as the standard of reference, the sensitivity of MRVC was 76.2%; the specificity, 90.0%; the positive predictive value, 88.9%; and the negative predictive value, 78.3%. There was concordance between two methods regarding the grade of reflux in all 16 ureterorenal units with VUR detected by both methods. Of 40 kidneys, MRVC detected findings of renal damage or reflux nephropathy in 13 kidneys, and (99m)Tc DMSA renal SPECT detected findings of reflux nephropathy in 17 kidneys. Although MRVC is shown to have less sensitivity for VUR than VCUG, MRVC may represent a method of choice offering a safer nonradiation test that can additionally evaluate the kidneys for changes related to reflux nephropathy. Copyright 2005 Wiley-Liss, Inc.

  18. Comprehensive Characterization of Voids and Microstructure in TATB-based Explosives from 10 nm to 1 cm: Effects of Temperature Cycling and Compressive Creep

    Energy Technology Data Exchange (ETDEWEB)

    Willey, T M; Lauderbach, L; Gagliardi, F; Cunningham, B; Lorenz, K T; Lee, J I; van Buuren, T; Call, R; Landt, L; Overturf, G

    2010-02-26

    This paper outlines the characterization of voids and Microstructure in TATB-based Explosives over several orders of magnitude, from sizes on the order of 10 nm to about 1 cm. This is accomplished using ultra small angle x-ray scattering to investigate voids from a few nm to a few microns, ultra small angle neutron scattering for voids from 100 nm to 10 microns, and x-ray computed microtomography to investigate microstructure from a few microns to a few centimeters. The void distributions of LX-17 are outlined, and the microstructure of LX-17 is presented. Temperature cycling and compressive creep cause drastically different damage to the microstructure. Temperature cycling leads to a volume expansion (ratchet growth) in TATB-based explosives, and x-ray scattering techniques that are sensitive to sizes up to a few microns indicated changes to the void volume distribution that had previously accounted for most, but not all of the change in density. This paper presents the microstructural damage larger than a few microns caused by ratchet growth. Temperature cycling leads to void creation in the binder poor regions associated with the interior portion of formulated prills. Conversely, compressive creep causes characteristically different changes to microstructure; fissures form at binder-rich prill boundaries prior to mechanical failure.

  19. Sandwich-like C@SnO2/Sn/void@C hollow spheres as improved anode materials for lithium ion batteries

    Science.gov (United States)

    Wang, Huijun; Jiang, Xinya; Chai, Yaqin; Yang, Xia; Yuan, Ruo

    2018-03-01

    As lithium ion batteries (LIBs) anode, SnO2 suffers fast capacity fading due to its large volume expansion during discharge/charge process. To overcome the problem, sandwich-like C@SnO2/Sn/void@C hollow spheres (referred as C@SnO2/Sn/void@C HSs) are prepared by in-situ polymerization and carbonization, using hollow SnO2 as self-template and dopamine as carbon source. The C@SnO2/Sn/void@C HSs possesses the merits of hollow and core/void/shell structure, so that they can accommodate the volume change under discharge/charge process, shorten the transmission distance of Li ions, own more contact area for the electrolyte. Thanks to these advantages, C@SnO2/Sn/void@C HSs display excellent electrochemical performance as anode materials for LIBs, which deliver a high capacity of 786.7 mAh g-1 at the current density of 0.5 A g-1 after 60 cycles. The simple synthesis method for C@SnO2/Sn/void@C HSs with special structure will provide a promising method for preparing other anode materials for LIBs.

  20. Maximum Acceleration Recording Circuit

    Science.gov (United States)

    Bozeman, Richard J., Jr.

    1995-01-01

    Coarsely digitized maximum levels recorded in blown fuses. Circuit feeds power to accelerometer and makes nonvolatile record of maximum level to which output of accelerometer rises during measurement interval. In comparison with inertia-type single-preset-trip-point mechanical maximum-acceleration-recording devices, circuit weighs less, occupies less space, and records accelerations within narrower bands of uncertainty. In comparison with prior electronic data-acquisition systems designed for same purpose, circuit simpler, less bulky, consumes less power, costs and analysis of data recorded in magnetic or electronic memory devices. Circuit used, for example, to record accelerations to which commodities subjected during transportation on trucks.

  1. A void fraction model for annular two-phase flow

    Energy Technology Data Exchange (ETDEWEB)

    Tandon, T.N.; Gupta, C.P.; Varma, H.K.

    1985-01-01

    An analytical model has been developed for predicting void fraction in two-phase annular flow. In the analysis, the Lockhart-Martinelli method has been used to calculate two-phase frictional pressure drop and von Karman's universal velocity profile is used to represent the velocity distribution in the annular liquid film. Void fractions predicted by the proposed model are generally in good agreement with a available experimental data. This model appears to be as good as Smith's correlation and better than the Wallis and Zivi correlations for computing void fraction.

  2. Radiation-induced void swelling in metals and alloys

    International Nuclear Information System (INIS)

    Zelinskij, V.F.; Neklyudov, I.M.; Ozhigov, L.S.; Reznichenko, Eh.A.; Rozhkov, V.V.; Chernyaeva, T.T.

    1979-01-01

    Main regularities in the development of radiation-induced void swelling are considered. Special attention is paid to consideration of a possibility to obtain information on material behaviour under conditions of reactor irradiation proceeding from the data of simulation experiments and to methods of rate control, for the processes which occur in material during irradiation and further annealing by the way of rationalized alloying, of thermomechanical treatment and programmed change of irradiation conditions under operation. Problems of initiation and growth of voids in irradiated materials are discussed as well as the ways to decrease the rate of radiation-induced void swelling

  3. Numerical simulation of void growth under dynamic loading

    International Nuclear Information System (INIS)

    Iqbal, A.

    1996-01-01

    Following a brief general review of developments in material behavior under high strain rates, a cylindrical cell surrounding a spherical void in OFHC copper is numerically simulated by Zerri-Armstrong model. This simulation results show that the plastic deformation tends to be concentrated in the vicinity of voids either in the axial or transverse direction depending upon the stress state. This event is associated with the accelerated void through accompanying coalescence causing ductile fracture. A3-node triangular mesh generation code used as input for finite element code is developed by a 'Central Generation' technique. (author)

  4. Local void and slip model used in BODYFIT-2PE

    International Nuclear Information System (INIS)

    Chen, B.C.J.; Chien, T.H.; Kim, J.H.; Lellouche, G.S.

    1983-01-01

    A local void and slip model has been proposed for a two-phase flow without the need of fitting any empirical parameters. This model is based on the assumption that all bubbles have reached their terminal rise velocities in the two-phase region. This simple model seems to provide reasonable calculational results when compared with the experimental data and other void and slip models. It provides a means to account for the void and slip of a two-phase flow on a local basis. This is particularly suitable for a fine mesh thermal-hydraulic computer program such as BODYFIT-2PE

  5. On the prediction of ductile fracture by void coalescence and strain localization

    Science.gov (United States)

    Luo, Tuo; Gao, Xiaosheng

    2018-04-01

    This paper presents a unit cell model based on the observation that ductile fracture occurs when plastic flow is localized in a band. The unit cell consists of three void containing material units stacked in the direction normal to the localization plane. Localization takes place in the middle material unit while the two outer units undergo elastic recovery after failure occurs. Thus a failure criterion is established as when the macroscopic effective strain of the outer material units reaches the maximum value. Analyses are conducted to demonstrate the effect of the voids existing outside the localization band. Comparisons of the present model with several previous models suggest that the present model is not only easy to implement in finite element analysis but also more suitable to robustly determine the failure strain. A series of unit cell analyses are conducted for various macroscopic stress triaxialities and Lode parameters. The analysis results confirm that for a fixed Lode parameter, the failure strain decreases exponentially with the stress triaxiality and for a given stress triaxiality, it increases as the stress state approaches the generalized tension and generalized compression. The analysis results also reveal the effect of the stress state on the deformed void shape within and near the localization band.

  6. Hillock Formation, Metal Lifting and Voiding of an AlCu Metallization due to Temperature Treatment

    International Nuclear Information System (INIS)

    Foerster, J.; Schuderer, B.; Haeuser, M.; Kallensee, O.; Gross, Th.

    2004-01-01

    A metalstack with a layer composition of Ti/TiN/AlCu/TiN was evaluated in an AlCu metallization. Reliability results show a higher electromigration lifetime compared to a Ti/AlCu/Ti/TiN stack. During the metallization process flow large elevations were seen by optical inspection. Analysis by SEM cross sections showed different deviations. A metal lifting with void formation as consequence was found in large aluminum areas above tungsten plugs. Also voiding in the passivated Metal 2 and the unpassivated Metal 3 with a cracked anti-reflective coating as a result of the expansion of the aluminum was seen. The influence of processes with high thermal budget on the stress behaviour of the new metalstack was investigated. The final annealing was found as the process with the most critical influence. This study shows the influence of different final annealing temperatures on hillock formation and voiding using a Ti/TiN/AlCu/TiN metalstack. A reduction of the maximum temperature of the final annealing process is necessary for using the new AlCu metallization stack. The use of a surface treatment before deposition showed an optimization of the adhesion

  7. The preventive effect of tamsulosin on voiding dysfunction after prostate biopsy: a prospective, open-label, observational study.

    Science.gov (United States)

    Chung, Seung Jun; Jung, Seung Il; Ryu, Ji Won; Hwang, Eu Chang; Kwon, Dong Deuk; Park, Kwangsung; Kim, Jin Woong

    2015-05-01

    To evaluate the association of prostate biopsy with voiding impairment and to investigate whether tamsulosin treatment given before prostate biopsy could improve voiding dysfunction after the procedure. The study included 88 consecutive patients who underwent transrectal ultrasound-guided prostate biopsy without prior BPH medication and were prospectively randomized. Of these 88 patients, 44 patients underwent prostate biopsy only without tamsulosin treatment and served as the control group. The remaining 44 patients were treated with tamsulosin (0.2 mg daily) beginning the day before the biopsy procedure for 7 days. The International Prostate Symptom Score (IPSS) was recorded in all patients before the procedure and on postbiopsy day 7. Maximal flow rate (Q(max)) and postvoid residual urine volume were recorded in all patients before the procedure and on postbiopsy days 1 and 7. No difference was found in baseline characteristics between the two groups. The IPSS (total, storage, and voiding symptom) was not significantly changed after biopsy in both groups. In the control group, the postvoid residual urine volume was increased on postbiopsy days 1 (P tamsulosin group, Q(max) was significantly increased on postbiopsy days 1 and 7 (P tamsulosin group, but it developed in two patients (4.5%) of the control group. The results of our study show that prostate biopsy leads to objective voiding impairment. Therefore, the use of alpha-1 blocker tamsulosin before biopsy in patients without prior BPH medication may decrease this morbidity.

  8. Influence of void effects on reactivity of coupled fast-thermal system HERBE

    International Nuclear Information System (INIS)

    Ljubenov, V.; Milovanovic, S.; Milovanovic, T.; Cuknic, O.

    1997-01-01

    Coupled fast-thermal system HERBE at the experimental zero power heavy water reactor RB is a system with the significant effects of the neutron leakage and neutron absorption. Presence of a coolant void introduces a new structure in an extremely heterogeneous core. In those conditions satisfactory results of the calculation are acquired only using specified space-energy homogenization procedure. In order to analyze transient appearances and accidental cases of the reactor systems, a procedure for modeling of influence of moderator and coolant loss on reactivity ('void effect') is developed. Reduction of the moderator volume fraction in some fuel channels due to air gaps or steam generation during the accidental moderator boiling, restricts validity of the diffusion approximation in the reactor calculations. In cases of high neutron flux gradients, which are consequence of high neutron absorption, application of diffusion approximation is questionable too. The problem may be solved using transport or Monte Carlo methods, but they are not acceptable in the routine applications. Applying new techniques based on space-energy core homogenization, such as the SPH method or the discontinuity factor method, diffusion calculations become acceptable. Calculations based on the described model show that loss of part of moderator medium introduce negative reactivity in the HERBE system. Calculated local void reactivity coefficients are used in safety analysis of hypothetical accidents

  9. A void ratio dependent water retention curve model including hydraulic hysteresis

    Directory of Open Access Journals (Sweden)

    Pasha Amin Y.

    2016-01-01

    Full Text Available Past experimental evidence has shown that Water Retention Curve (WRC evolves with mechanical stress and structural changes in soil matrix. Models currently available in the literature for capturing the volume change dependency of WRC are mainly empirical in nature requiring an extensive experimental programme for parameter identification which renders them unsuitable for practical applications. In this paper, an analytical model for the evaluation of the void ratio dependency of WRC in deformable porous media is presented. The approach proposed enables quantification of the dependency of WRC on void ratio solely based on the form of WRC at the reference void ratio and requires no additional parameters. The effect of hydraulic hysteresis on the evolution process is also incorporated in the model, an aspect rarely addressed in the literature. Expressions are presented for the evolution of main and scanning curves due to loading and change in the hydraulic path from scanning to main wetting/drying and vice versa as well as the WRC parameters such as air entry value, air expulsion value, pore size distribution index and slope of the scanning curve. The model is validated using experimental data on compacted and reconstituted soils subjected to various hydro-mechanical paths. Good agreement is obtained between model predictions and experimental data in all the cases considered.

  10. Maximum Quantum Entropy Method

    OpenAIRE

    Sim, Jae-Hoon; Han, Myung Joon

    2018-01-01

    Maximum entropy method for analytic continuation is extended by introducing quantum relative entropy. This new method is formulated in terms of matrix-valued functions and therefore invariant under arbitrary unitary transformation of input matrix. As a result, the continuation of off-diagonal elements becomes straightforward. Without introducing any further ambiguity, the Bayesian probabilistic interpretation is maintained just as in the conventional maximum entropy method. The applications o...

  11. Maximum power demand cost

    International Nuclear Information System (INIS)

    Biondi, L.

    1998-01-01

    The charging for a service is a supplier's remuneration for the expenses incurred in providing it. There are currently two charges for electricity: consumption and maximum demand. While no problem arises about the former, the issue is more complicated for the latter and the analysis in this article tends to show that the annual charge for maximum demand arbitrarily discriminates among consumer groups, to the disadvantage of some [it

  12. Stress redistribution and void growth in butt-welded canisters for spent nuclear fuel

    International Nuclear Information System (INIS)

    Josefson, B.L.; Karlsson, L.; Haeggblad, H.Aa.

    1993-02-01

    The stress-redistribution in Cu-Fe canisters for spent nuclear fuel during waiting for deposition and after final deposition is calculated numerically. The constitutive equation modelling creep deformation during this time period employs values on materials parameters determined within the SKB-project on 'mechanical integrity of canisters for spent nuclear fuel'. The welding residual stresses are redistributed without lowering maximum values during the waiting period, a very low amount of void growth is predicted for this type of copper during the deposition period. This leads to an estimated very large rupture time

  13. Voiding Chain Cystourethography: Assessing A Historical Test's Role in Selection for Urethrolysis

    Directory of Open Access Journals (Sweden)

    Steven P Petrou

    2013-07-01

    Full Text Available Objective To analyze the benefit of voiding chain cystourethrography (VCC [placing a radiographic opaque chain into the urethra and bladder and asking the patient to void under fluoroscopy] in the urodynamic evaluation of female bladder outlet obstruction (BOO. Materials and Methods Females with post anti-incontinence operation voiding dysfunction who underwent urodynamic evaluation augmented with VCC and later had urethrolysis were identified. Six diagnostic criteria for obstruction were applied to each patient: (1 VCC ( obstructed: chain was angulated and could not be voiding out (2 Video urodynamic study (VUDS (detrusor contraction combined with radiographic obstruction (3 maximum flow (Qmax ≤ 15 cc/sec, detrusor pressure (pDet@ Qmax ≥ 20 cm H20 (4 Qmax ≤ 11 cc/sec, pDet@ Qmax ≥ 25 cm H20 (5 Qmax ≤ 12 cc/sec, pDet@ Qmax ≥ 25 cm H20 (6 Blaivas-Groutz (B-G nomogram. Urethrolysis results were reviewed. Agreement in assessment of BOO criteria was assessed by estimating the proportion of pair-wise agreements along with an exact binomial 95% confidence interval (CI and by estimating kappa along with a 95% CI. Results Twenty-one patients were identified. Twenty of the 22 urethrolyses (91% were clinically successful. Diagnosis of BOO was most common for VCC (86% and then B-G Nomogram (67%. Agreement with the VCC was relatively poor for each of the five other methods (14%-62% with the video urodynamic study (VUDS being the best. Three patients with successful urethrolysis were diagnosed only by the VCC. All of kappa values regarding agreement with the VCC were low; the highest value of 0.15 was observed for VUDS. Conclusion VCC may augment selection criteria for urethrolysis.

  14. Utilization of crushed radioactive concrete for mortar to fill waste container void space

    International Nuclear Information System (INIS)

    Ishikura, Takeshi; Ohnishi, Kazuhiko; Oguri, Daiichiro; Ueki, Hiroyuki

    2004-01-01

    Minimizing the volume of radioactive waste generated during dismantling of nuclear power plants is a matter of great importance. In Japan waste forms buried in a shallow burial disposal facility as low level radioactive waste must be solidified by cement or other materials with adequate strength and must provide no harmful opening. The authors have developed an improved method to minimize radioactive waste volume by utilizing radioactive concrete for fine aggregate for mortars to fill void space in waste containers. Tests were performed with pre-placed concrete waste and with filling mortar using recycled fine aggregate produced from concrete. It was estimated that the improved method substantially increases the waste fill ratio in waste containers, thereby decreasing the total volume of disposal waste. (author)

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

    International Nuclear Information System (INIS)

    Ortega, Y.; Monge, M.A.; Castro, V. de; Munoz, A.; Leguey, T.; Pareja, R.

    2009-01-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-04-30

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

  17. Comment on theories for helium-assisted void nucleation

    International Nuclear Information System (INIS)

    Russell, K.C.

    1976-01-01

    Voids form by agglomeration of irradiation-induced vacancies which remain after preferential absorption of self interstitials at dislocation lines. Helium which is formed by (n,α) transmutations and, in simulation studies, may be ion-implanted, often plays an important, but puzzling role. In some materials, very few voids form in the absence of helium, even after intense irradiation. In many other materials , voids form readily under a variety of irradiation conditions, even in the absence of helium. Why some materials require helium - typically in the 10 -6 apa (atom per atom) range - and others do not, and the reason for that particular level are by no means clear. The physics of void nucleation, particularly the role of helium, have been the subject of several theoretical papers. This note presents a critique of these theories, and then briefly outlines a new analysis which is not subject to their limitations. (Auth.)

  18. 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.

  19. One normal void and residual following MUS surgery is all that is necessary in most patients.

    Science.gov (United States)

    Ballard, Paul; Shawer, Sami; Anderson, Colette; Khunda, Aethele

    2018-04-01

    There is considerable variation worldwide on how the assessment of voiding function is performed following midurethral sling (MUS) surgery. There is potentially a financial cost, and reduction in efficiency when patient discharge is delayed. Using our current practice of two normal void and residual (V&R) readings before discharge, the aim of this retrospective study was to evaluate the likelihood of an abnormal second V&R test if the first V&R test was normal in order to determine if a policy of discharge after only one satisfactory V&R test is reasonable. Data from 400 patients who had had MUS surgery with or without other procedures were collected. Our unit protocol included two consecutive voids of greater than 200 ml with residuals less than 150 ml before discharge. The patients were divided into the following groups: MUS only, MUS plus anterior colporrhaphy (AR) plus any other procedures (MUS/AR), and MUS with any non-AR procedures (MUS+). Complete datasets were available for 335 patients. Once inadequate tests (low volume voids <200 ml) had been excluded (28% overall), the likelihood of an abnormal second V&R test if the first test was normal was 7.1% overall, but 3.6% for MUS, 11.5% for MUS/AR and 8.6% for MUS+. The findings in the MUS-only group indicate that it is probably safe to discharge patients after one satisfactory V&R test, as long as safety measures such as 'open access' are available so that patients have unhindered readmission if problems arise.

  20. (100) faceted anion voids in electron irradiated fluorite

    International Nuclear Information System (INIS)

    Johnson, E.

    1979-01-01

    High fluence electron irradiation of fluorite crystals in the temperature range 150 to 320 K results in formation of a simple cubic anion void superlattice. Above 320 K the damage structure changes to a random distribution of large [001] faceted anion voids. This voidage behaviour, similar to that observed in a range of irradiated metals, is discussed in terms points defect rather than conventional colour centre terminology. (Auth.)

  1. 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....

  2. Effect of Dark Energy Perturbation on Cosmic Voids Formation

    Science.gov (United States)

    Endo, Takao; Nishizawa, Atsushi J.; Ichiki, Kiyotomo

    2018-05-01

    In this paper, we present the effects of dark energy perturbation on the formation and abundance of cosmic voids. We consider dark energy to be a fluid with a negative pressure characterised by a constant equation of state w and speed of sound c_s^2. By solving fluid equations for two components, namely, dark matter and dark energy fluids, we quantify the effects of dark energy perturbation on the sizes of top-hat voids. We also explore the effects on the size distribution of voids based on the excursion set theory. We confirm that dark energy perturbation negligibly affects the size evolution of voids; c_s^2=0 varies the size only by 0.1% as compared to the homogeneous dark energy model. We also confirm that dark energy perturbation suppresses the void size when w -1 (Basse et al. 2011). In contrast to the negligible impact on the size, we find that the size distribution function on scales larger than 10 Mpc/h highly depends on dark energy perturbation; compared to the homogeneous dark energy model, the number of large voids of radius 30Mpc is 25% larger for the model with w = -0.9 and c_s^2=0 while they are 20% less abundant for the model with w = -1.3 and c_s^2=0.

  3. Measurement of local void fraction in a ribbed annulus

    International Nuclear Information System (INIS)

    Steimke, J.L.

    1992-01-01

    The computer code FLOWTRAN-TF is used to analyze hypothetical hydraulic accidents for the nuclear reactor at the Savannah River Site. During a hypothetical Large Break Loss-of-Coolant Accident (LOCA), reactor assemblies would contain a two-phase mixture of air and water which flows downward. Reactor assemblies consist of nested, ribbed annuli. Longitudinal ribs divide each annulus into four subchannels. For accident conditions, air and water can flow past ribs from one subchannel to another. For FLOWTRAN-TF to compute the size of those flows, it is necessary to know the local void fraction in the region of the rib. Measurements have previously been made of length-average void fraction in a ribbed annulus. However, no direct measurements were available of local void fraction. Due to the lack of data, a test was designed to measure local void fraction at the rib. One question addressed by the test was whether void fraction at the rib is solely a function of azimuthal-average void fraction or a function of additional variables such as pressure boundary conditions. This report provides a discussion of this test

  4. Influence of the void fraction in the linear reactivity model

    International Nuclear Information System (INIS)

    Castillo, J.A.; Ramirez, J.R.; Alonso, G.

    2003-01-01

    The linear reactivity model allows the multicycle analysis in pressurized water reactors in a simple and quick way. In the case of the Boiling water reactors the void fraction it varies axially from 0% of voids in the inferior part of the fuel assemblies until approximately 70% of voids to the exit of the same ones. Due to this it is very important the determination of the average void fraction during different stages of the reactor operation to predict the burnt one appropriately of the same ones to inclination of the pattern of linear reactivity. In this work a pursuit is made of the profile of power for different steps of burnt of a typical operation cycle of a Boiling water reactor. Starting from these profiles it builds an algorithm that allows to determine the voids profile and this way to obtain the average value of the same one. The results are compared against those reported by the CM-PRESTO code that uses another method to carry out this calculation. Finally, the range in which is the average value of the void fraction during a typical cycle is determined and an estimate of the impact that it would have the use of this value in the prediction of the reactivity produced by the fuel assemblies is made. (Author)

  5. Experimental investigation of void distribution in Suppression Pool during the initial blowdown period of a Loss of Coolant Accident using air–water two-phase mixture

    International Nuclear Information System (INIS)

    Rassame, Somboon; Griffiths, Matthew; Yang, Jun; Lee, Doo Yong; Ju, Peng; Choi, Sung Won; Hibiki, Takashi; Ishii, Mamoru

    2014-01-01

    Highlights: • Basic understanding of the venting phenomena in the SP during a LOCA was obtained. • A series of experiment is carried out using the PUMA-E test facility. • Two phases of experiments, namely, an initial and a quasi-steady phase were observed. • The maximum void penetration depth was experienced during the initial phase. - Abstract: During the initial blowdown period of a Loss of Coolant Accident (LOCA), the non-condensable gas initially contained in the BWR containment is discharged to the pressure suppression chamber through the blowdown pipes. The performance of Emergency Core Cooling System (ECCS) can be degraded due to the released gas ingestion into the suction intakes of the ECCS pumps. The understanding of the relevant phenomena in the pressure suppression chamber is important in analyzing potential gas intrusion into the suction intakes of ECCS pumps. To obtain the basic understanding of the relevant phenomena and the generic data of void distribution in the pressure suppression chamber during the initial blowdown period of a LOCA, tests with various blowdown conditions were conducted using the existing Suppression Pool (SP) tank of the integral test facility, called Purdue University Multi-Dimensional Integral Test Assembly for ESBWR applications (PUMA-E) facility, a scaled downcomer pipe installed in the PUMA-E SP, and air discharge pipe system. Two different diameter sizes of air injection pipe (0.076 and 0.102 m), a range of air volumetric flux (7.9–24.7 m/s), initial void conditions in an air injection pipe (fully void, partially void, and fully filled with water) and different air velocity ramp rates (1.0, 1.5, and 2.0 s) are used to investigate the impact of the blowdown conditions to the void distribution in the SP. Two distinct phases of experiments, namely, an initial and a quasi-steady phase were observed. The maximum void penetration depth was experienced during the initial phase. The quasi-steady phase provided less void

  6. 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...... a maximum in all the cases analyzed and thus illustrates the micro-mechanism leading to failure of the material by localization of plastic flow....

  7. Maximum likely scale estimation

    DEFF Research Database (Denmark)

    Loog, Marco; Pedersen, Kim Steenstrup; Markussen, Bo

    2005-01-01

    A maximum likelihood local scale estimation principle is presented. An actual implementation of the estimation principle uses second order moments of multiple measurements at a fixed location in the image. These measurements consist of Gaussian derivatives possibly taken at several scales and/or ...

  8. Robust Maximum Association Estimators

    NARCIS (Netherlands)

    A. Alfons (Andreas); C. Croux (Christophe); P. Filzmoser (Peter)

    2017-01-01

    textabstractThe maximum association between two multivariate variables X and Y is defined as the maximal value that a bivariate association measure between one-dimensional projections αX and αY can attain. Taking the Pearson correlation as projection index results in the first canonical correlation

  9. Urinary tract infection after voiding cystourethrogram.

    Science.gov (United States)

    Johnson, E K; Malhotra, N R; Shannon, R; Jacobson, D L; Green, J; Rigsby, C K; Holl, J L; Cheng, E Y

    2017-08-01

    Reported rates of post-procedural urinary tract infection (ppUTI) after voiding cystourethrogram (VCUG) are highly variable (0-42%). This study aimed to determine the risk of ppUTI after cystogram, and evaluate predictors of ppUTI. A retrospective cohort study of children undergoing VCUG or radionuclide cystogram (henceforth 'cystogram') was conducted. Children with neurogenic bladder who underwent cystogram in the operating room and without follow-up at the study institution were excluded. Incidence of symptomatic ppUTI within 7 days after cystogram was recorded. Predictors of ppUTI were evaluated using univariate statistics. A total of 1108 children (54% female, median age 1.1 years) underwent 1203 cystograms: 51% were on periprocedural antibiotics, 75% had a pre-existing urologic diagnosis (i.e., vesicoureteral reflux (VUR) or hydronephrosis; not UTI alone), and 18% had a clinical UTI within 30 days before cystogram. Of the cystograms, 41% had an abnormal cystogram and findings included VUR (82%), ureterocele (6%), and diverticula (6%). Twelve children had a ppUTI (1.0%; four girls, five uncircumcised boys, three circumcised boys; median age 0.9 years). Factors significantly associated with diagnosis of a ppUTI (Summary fig.) included: pre-existing urologic diagnosis prior to cystogram (12/12, 100% of patients with ppUTI), abnormal cystogram results (11/12, 92%), and use of periprocedural antibiotics (11/12, 92%). All 11 children with an abnormal cystogram had VUR ≥ Grade III. However, among all children with VUR ≥ Grade III, 4% (11/254) had a ppUTI. This is the largest study to date that has examined incidence and risk factors for ppUTI after cystogram. The retrospective nature of the study limited capture of some clinical details. This study demonstrated that the risk of ppUTI after a cystogram is very low (1.0% in this cohort). Having a pre-existing urologic diagnosis such as VUR or hydronephrosis was associated with ppUTI; therefore, children with

  10. Influence of Poly(ethylene glycol) Degradation on Voiding Sporadically Occurring in Solder Joints with Electroplated Cu

    Science.gov (United States)

    Wafula, F.; Yin, L.; Borgesen, P.; Andala, D.; Dimitrov, N.

    2012-07-01

    This paper presents a comprehensive study of the effect of poly(ethylene glycol) (PEG) degradation on the void formation known to take place sporadically at the interface between electroplated Cu and Pb-free solder. Thorough chemical analysis of our plating solution, carried out at different times of the deposition process by matrix-assisted laser desorption ionization time-of-flight mass spectroscopy, reveals a dramatic shift in the peaks to lower mass range with time. Scanning electron microscopy cross-sectional images of solder joints with Cu samples that have been plated at different times in the course of solution aging show a decrease in void formation. A decreasing magnitude of the deposition overpotential also seen during aging suggests that, breaking down to lower-molecular-weight fragments, PEG loses its suppression effect and likely has lower impact on the voiding propensity. This indirect correlation is confirmed further by the use of plating solutions containing PEG with preselected molecular weight. We also report on the effect of the surface area-to-solution volume ratio on PEG degradation studied by comparative experiments performed in a 50-mL bath with a rotating disc electrode and in a larger cell (Hull cell) with volume of 267 mL. The results show that, at fixed charge per unit volume, PEG degrades at a greatly accelerated rate in the Hull cell featuring higher electrode surface-to-solution volume ratio. Analysis of solder joints with accordingly grown Cu layers suggests that the voiding decreases faster with the accelerated rate of PEG degradation.

  11. Reliability Impact of Stockpile Aging: Stress Voiding; TOPICAL

    International Nuclear Information System (INIS)

    ROBINSON, DAVID G.

    1999-01-01

    The objective of this research is to statistically characterize the aging of integrated circuit interconnects. This report supersedes the stress void aging characterization presented in SAND99-0975, ''Reliability Degradation Due to Stockpile Aging,'' by the same author. The physics of the stress voiding, before and after wafer processing have been recently characterized by F. G. Yost in SAND99-0601, ''Stress Voiding during Wafer Processing''. The current effort extends this research to account for uncertainties in grain size, storage temperature, void spacing and initial residual stress and their impact on interconnect failure after wafer processing. The sensitivity of the life estimates to these uncertainties is also investigated. Various methods for characterizing the probability of failure of a conductor line were investigated including: Latin hypercube sampling (LHS), quasi-Monte Carlo sampling (qMC), as well as various analytical methods such as the advanced mean value (Ah/IV) method. The comparison was aided by the use of the Cassandra uncertainty analysis library. It was found that the only viable uncertainty analysis methods were those based on either LHS or quasi-Monte Carlo sampling. Analytical methods such as AMV could not be applied due to the nature of the stress voiding problem. The qMC method was chosen since it provided smaller estimation error for a given number of samples. The preliminary results indicate that the reliability of integrated circuits due to stress voiding is very sensitive to the underlying uncertainties associated with grain size and void spacing. In particular, accurate characterization of IC reliability depends heavily on not only the frost and second moments of the uncertainty distribution, but more specifically the unique form of the underlying distribution

  12. 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

  13. Automated air-void system characterization of hardened concrete: Helping computers to count air-voids like people count air-voids---Methods for flatbed scanner calibration

    Science.gov (United States)

    Peterson, Karl

    Since the discovery in the late 1930s that air entrainment can improve the durability of concrete, it has been important for people to know the quantity, spacial distribution, and size distribution of the air-voids in their concrete mixes in order to ensure a durable final product. The task of air-void system characterization has fallen on the microscopist, who, according to a standard test method laid forth by the American Society of Testing and Materials, must meticulously count or measure about a thousand air-voids per sample as exposed on a cut and polished cross-section of concrete. The equipment used to perform this task has traditionally included a stereomicroscope, a mechanical stage, and a tally counter. Over the past 30 years, with the availability of computers and digital imaging, automated methods have been introduced to perform the same task, but using the same basic equipment. The method described here replaces the microscope and mechanical stage with an ordinary flatbed desktop scanner, and replaces the microscopist and tally counter with a personal computer; two pieces of equipment much more readily available than a microscope with a mechanical stage, and certainly easier to find than a person willing to sit for extended periods of time counting air-voids. Most laboratories that perform air-void system characterization typically have cabinets full of prepared samples with corresponding results from manual operators. Proponents of automated methods often take advantage of this fact by analyzing the same samples and comparing the results. A similar iterative approach is described here where scanned images collected from a significant number of samples are analyzed, the results compared to those of the manual operator, and the settings optimized to best approximate the results of the manual operator. The results of this calibration procedure are compared to an alternative calibration procedure based on the more rigorous digital image accuracy

  14. Maximum power point tracking

    International Nuclear Information System (INIS)

    Enslin, J.H.R.

    1990-01-01

    A well engineered renewable remote energy system, utilizing the principal of Maximum Power Point Tracking can be m ore cost effective, has a higher reliability and can improve the quality of life in remote areas. This paper reports that a high-efficient power electronic converter, for converting the output voltage of a solar panel, or wind generator, to the required DC battery bus voltage has been realized. The converter is controlled to track the maximum power point of the input source under varying input and output parameters. Maximum power point tracking for relative small systems is achieved by maximization of the output current in a battery charging regulator, using an optimized hill-climbing, inexpensive microprocessor based algorithm. Through practical field measurements it is shown that a minimum input source saving of 15% on 3-5 kWh/day systems can easily be achieved. A total cost saving of at least 10-15% on the capital cost of these systems are achievable for relative small rating Remote Area Power Supply systems. The advantages at larger temperature variations and larger power rated systems are much higher. Other advantages include optimal sizing and system monitor and control

  15. NJP VOLUME 41 NO 2

    African Journals Online (AJOL)

    PROF. EZECHUKWU

    2013-11-24

    Nov 24, 2013 ... nation and volume of urine voided; from1- 2 times to 10. -15 times during the day ... Serum electrolytes, urea and creatinine done on admis- sion showed ... cient synthesis and or release of AVP.7The clinical manifestation of ...

  16. ON THE STAR FORMATION PROPERTIES OF VOID GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Moorman, Crystal M.; Moreno, Jackeline; White, Amanda; Vogeley, Michael S. [Department of Physics, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104 (United States); Hoyle, Fiona [Pontifica Universidad Catolica de Ecuador, 12 de Octubre 1076 y Roca, Quito (Ecuador); Giovanelli, Riccardo; Haynes, Martha P., E-mail: crystal.m.moorman@drexel.edu [Center for Radiophysics and Space Research, Space Sciences Building, Cornell University Ithaca, NY 14853 (United States)

    2016-11-10

    We measure the star formation properties of two large samples of galaxies from the SDSS in large-scale cosmic voids on timescales of 10 and 100 Myr, using H α 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 H i detections from ALFALFA. For the full H i detected sample, SSFRs do not vary systematically with large-scale environment. However, investigating only the H i detected dwarf galaxies reveals a trend toward higher SSFRs in voids. Furthermore, we estimate the star formation rate per unit H i mass (known as the star formation efficiency; SFE) of a galaxy, as a function of environment. For the overall H i detected population, we notice no environmental dependence. Limiting the sample to dwarf galaxies still does not reveal a statistically significant difference between SFEs in voids versus walls. These results suggest that void environments, on average, provide a nurturing environment for dwarf galaxy evolution allowing for higher specific star formation rates while forming stars with similar efficiencies to those in walls.

  17. 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...

  18. How institutional voids influence Brazilian foreign direct investment in Angola

    Directory of Open Access Journals (Sweden)

    Renato Virches

    2017-04-01

    Full Text Available How do institutional voids influence emerging market multinationals (EMNEs foreign direct investment (FDI in developing countries? In this article we respond to this question by examining Brazilian FDI in Angola as our analytical setting. We focus on the host country’s institutions and its institutional voids as essential factors that attract the FDI of EMNES to developing countries. The research indicates that Brazilian companies fill in much of these voids within the market intermediaries, often creating a point of competitive advantage, and also creating advantages in relation to FDI from other economies that invest in Angola. The scarce literature on FDI in Africa has been largely dedicated to the analysis of Chinese investment in the region. We aim to complement recent research on the influence of the host country’s institutions on the behavior of FDI in developing countries, explaining how some EMNEs are able to use the institutional voids of developing countries as market opportunities. Our findings should provide also implications for EMNEs managers from other emerging markets by providing a better understanding of how Brazilian multinationals expand their business in less developed countries, handle institutional voids and manage relationships with local and foreign institutions in the host country.

  19. Understanding void fraction in steady state and dynamic environments

    International Nuclear Information System (INIS)

    Chexal, B.; Maulbetsch, J.; Harrison, J.; Petersen, C.; Jensen, P.; Horowitz, J.

    1997-01-01

    Understanding void fraction behavior in steady-state and dynamic environments is important to accurately predict the thermal-hydraulic behavior of two-phase or two-component systems. The Chexal-Lellouche (C-L) void fraction mode described herein covers the full range of pressures, flows, void fractions, and fluid types (steam-water, air-water, and refrigerants). A drift flux model formulation is used which covers the complete range of concurrent and countercurrent flows. The (1996) model revises the earlier C-L void fraction correlation, improves the capability of the model in countercurrent flow based on the incorporation of additional data, and improves the characteristics of the correlation that are important in transient programs. The model has been qualified with data from a number of steady state two-phase and two-component tests, and has been incorporated into the transient analysis code RELAP5 and RETRAN-3D and evaluated with a variety of transient and steady state tests. A 'plug-in' module for the void fraction correlation has been developed and implemented in RELAP5 and RETRAN-3D. The module is available as source code for inclusion into other thermal-hydraulic programs and can be used in any program that utilizes the same interface variables

  20. Effect of voids-controlled vacancy supersaturations on B diffusion

    International Nuclear Information System (INIS)

    Marcelot, O.; Claverie, A.; Cristiano, F.; Cayrel, F.; Alquier, D.; Lerch, W.; Paul, S.; Rubin, L.; Jaouen, H.; Armand, C.

    2007-01-01

    We present here preliminary results on boron diffusion in presence of pre-formed voids of different characteristics. The voids were fabricated by helium implantation followed by annealing allowing the desorption of He prior to boron implantation. We show that under such conditions boron diffusion is always largely reduced and can even be suppressed in some cases. Boron diffusion suppression can be observed in samples not containing nanovoids in the boron-rich region. It is suggested that direct trapping of Si(int)s by the voids is not the mechanism responsible for the reduction of boron diffusion in such layers. Alternatively, our experimental results suggest that this reduction of diffusivity is more probably due to the competition between two Ostwald ripening phenomena taking place at the same time: in the boron-rich region, the competitive growth of extrinsic defects at the origin of TED and, in the void region, the Ostwald ripening of the voids which involves large supersaturations of Vs

  1. Effect of voids-controlled vacancy supersaturations on B diffusion

    Energy Technology Data Exchange (ETDEWEB)

    Marcelot, O. [CEMES/CNRS, 29 rue Jeanne Marvig, 31055 Toulouse (France)]. E-mail: marcelot@cemes.fr; Claverie, A. [CEMES/CNRS, 29 rue Jeanne Marvig, 31055 Toulouse (France); Cristiano, F. [LAAS/CNRS, 7 av. du Col. Roche, 31077 Toulouse (France); Cayrel, F. [LMP, Universite de Tours, 16 rue Pierre et Marie Curie, BP 7155, 37071 Tours (France); Alquier, D. [LMP, Universite de Tours, 16 rue Pierre et Marie Curie, BP 7155, 37071 Tours (France); Lerch, W. [Mattson Thermal Products GmbH, Daimlerstr. 10, D-89160 Dornstadt (Germany); Paul, S. [Mattson Thermal Products GmbH, Daimlerstr. 10, D-89160 Dornstadt (Germany); Rubin, L. [Axcelis Technologies, 108 Cherry Hill Drive, Beverly MA 01915 (United States); Jaouen, H. [STMicroelectronics, 850 rue Jean Monnet, 38926 Crolles (France); Armand, C. [LNMO/INSA, Service analyseur ionique, 135 av. de Rangueil, 31077 Toulouse (France)

    2007-04-15

    We present here preliminary results on boron diffusion in presence of pre-formed voids of different characteristics. The voids were fabricated by helium implantation followed by annealing allowing the desorption of He prior to boron implantation. We show that under such conditions boron diffusion is always largely reduced and can even be suppressed in some cases. Boron diffusion suppression can be observed in samples not containing nanovoids in the boron-rich region. It is suggested that direct trapping of Si(int)s by the voids is not the mechanism responsible for the reduction of boron diffusion in such layers. Alternatively, our experimental results suggest that this reduction of diffusivity is more probably due to the competition between two Ostwald ripening phenomena taking place at the same time: in the boron-rich region, the competitive growth of extrinsic defects at the origin of TED and, in the void region, the Ostwald ripening of the voids which involves large supersaturations of Vs.

  2. Impact of convenience void in a bladder diary with urinary perception grade to assess overactive bladder symptoms: a community-based study.

    Science.gov (United States)

    Honjo, Hisashi; Kawauchi, Akihiro; Nakao, Masahiro; Ukimura, Osamu; Kitakoji, Hiroshi; Miki, Tsuneharu

    2010-09-01

    Bladder diaries including bladder perception grade were analyzed to assess convenience void (CV) in community-dwelling women 40 years of age or older. A total of 310 women completed a 3-day bladder diary with a grade for bladder perception. The grade was defined on scores 0-5 as follows: 0 = No bladder sensation, 1 = Sensation of bladder filling without desire to void, 2 = Desire to void, 3 = Strong desire to void, 4 = Urgency without urge urinary incontinence (UUI), and 5 = Urge incontinence episode. CV was defined as void without desire to void: when the grade was 0, CV in a narrow sense, and when 0 or 1, CV in a broad sense. The incidence of CV in the broad sense significantly decreased with age. Of the 310 women, 48 (15.5%) had overactive bladder (OAB) symptoms on the medical interview, including 37 (11.9%) without UUI (OAB-Dry) and 11 (3.5%) with UUI (OAB-Wet). Of the remaining 262 women, 111 (35.8%), who had urgency but a urinary frequency of 7 or less, and another 141 (48.7%) were classified into the Normal with Urgency and Normal without Urgency groups, respectively. The incidence of CV in a broad sense in the Normal without Urgency group was significantly greater than that in the Normal with Urgency and OAB-Wet groups. The mean voided volumes of CV in the broad sense in the OAB-Wet group were significantly smaller than those in the other three groups. The evaluation of CV may be a new tool in assessing storage condition and voiding dysfunction. © 2010 Wiley-Liss, Inc.

  3. Experimental investigation of void distribution in suppression pool over the duration of a loss of coolant accident using steam–water two-phase mixture

    International Nuclear Information System (INIS)

    Rassame, Somboon; Griffiths, Matthew; Yang, Jun; Ju, Peng; Sharma, Subash; Hibiki, Takashi; Ishii, Mamoru

    2015-01-01

    Highlights: • Experiments were conducted to study void fraction distribution in SP during blowdown. • 3 Experimental phases, namely, an initial and a quasi-steady phase, chugging were observed. • The maximum void penetration depth was experienced during the initial phase. • The quasi-steady phase provided less void penetration depth with oscillations. • The chugging phase was experienced at the end of experimental phase. - Abstract: Studies are underway to determine if a large amount gas discharged through the downcomer pipes in the pressure suppression chamber during the blowdown of Loss of Coolant Accident (LOCA) can potentially be entrained into the Emergency Core Cooling System (ECCS) suction piping of BWR. This may result in degraded ECCS pumps performance which could affect the ability to maintain or recover the water inventory level in the Reactor Pressure Vessel (RPV) during a LOCA. Therefore, it is very important to understand the void behavior in the pressure suppression chamber during the blowdown period of a LOCA. To address this issue, a set of experiments is conducted using the Purdue University Multi-Dimensional Integral Test Assembly for ESBWR applications (PUMA-E) facility. The geometry of the test apparatus is determined based on the basic geometrical scaling analysis from a prototypical BWR containment (MARK I) with a consideration of downcomer size, downcomer water submergence depth and Suppression Pool (SP) water level. Several instruments are installed in the test facility to measure the required experimental data such as the steam mass flow rate, void fraction, pressure and temperature. In the experiments, sequential flows of air, steam–air mixture and pure steam-each with the various flow rate conditions are injected from the Drywell (DW) through a downcomer pipe in the SP. Eight tests with two different downcomer sizes, various initial gas volumetric fluxes at the downcomer, and two different initial non-condensable gas

  4. The relationship between temperament, gender, and childhood dysfunctional voiding.

    Science.gov (United States)

    Colaco, Marc; Dobkin, Roseanne D; Sterling, Matthew; Schneider, Dona; Barone, Joseph

    2013-08-01

    Dysfunctional voiding (DV) is an extremely common pediatric complaint. The goal of this study was to examine the relationship between DV and childhood temperament. Information about the voiding behaviors and temperaments of 50 children was examined using a case-control model. Caregivers were asked to fill out the Children's Behavior Questionnaire in order to rate their child on the dimensions of surgency, negative affect, and effortful control. The relationship between DV and these dimensions was then evaluated. Males with DV were found to have lower effortful control than males with normal voiding habits. Females with DV did not demonstrate a difference in effortful control, but did demonstrate a higher rate of surgency. The results suggest that temperament does have an association with DV. These findings are in line with temperamental associations with other externalizing trouble behaviors and may inform potential treatment strategies for DV.

  5. Prediction of pool void fraction by new drift flux correlation

    International Nuclear Information System (INIS)

    Kataoka, I.; Ishii, M.

    1986-06-01

    A void fraction for a bubbling or boiling pool system is one of the important parameters in analyzing heat and mass transfer processes. Using the drift flux formulation, correlations for the pool void fraction have been developed in collaboration with a large number of experimental data. It has been found that the drift velocity in a pool system depends upon vessel diameter, system pressure, gas flux and fluid physical properties. The results show that the relative velocity and void fraction can be quite different from those predicted by conventional correlations. In terms of the rise velocity, four different regimes are identified. These are bubbly, churn-turbulent, slug and cap bubble regimes. The present correlations are shown to agree with the experimental data over wide ranges of parameters such as vessel diameter, system pressure, gas flux and physical properties. 39 refs., 41 figs

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

    Directory of Open Access Journals (Sweden)

    Chen Barad

    2017-12-01

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

  7. Multiple void formation in plasmas containing multispecies charged grains

    International Nuclear Information System (INIS)

    Liu, Y. H.; Chen, Z. Y.; Bogaerts, A.; Yu, M. Y.

    2006-01-01

    Self-organized separation of charged-dust species in two-dimensional dusty plasmas is studied by means of molecular-dynamics simulation. The multispecies dust grains, interacting through a screened Coulomb potential with a long-range attractive component, are confined by an external quadratic potential and subjected to a radially outward ion drag force. It is found that, in general, the species are spatially separated by bandlike dust-free (or void) regions, and grains of the same species tend to populate a common shell. At large ion drag and/or large plasma screening, a central disklike void as well as concentric bandlike voids separating the different species appear. Because of the outward drag and the attractive component of the dust-dust interaction forces, highly asymmetrical states consisting of species-separated dust clumps can also exist despite the fact that all the forces are either radial or central

  8. A DRAGON-MCNP comparison of void reactivity calculations

    Energy Technology Data Exchange (ETDEWEB)

    Marleau, G [Ecole Polytechnique, Montreal, PQ (Canada). Inst. de Genie Nucleaire; Milgram, M S [Atomic Energy of Canada Ltd., Chalk River, ON (Canada)

    1996-12-31

    The determination of the reactivity coefficients associated with coolant voiding in a CANDU reactor is a subject which has attracted a large amount of interest in the last few years both from the theoretical and experimental point of view. One expects that deterministic codes such as DRAGON and WIMS-AECL or the MCNP4 Monte Carlo code should be able to adequately simulate the cell behaviour upon coolant voiding. However, the absence of an experimental database at equilibrium and discharge burnups has not permitted the full validation of any of these lattice codes, although a partial validation through comparison of two different computer codes has been considered. Here we present a comparison between DRAGON and MCNP4 of the void reactivity evaluation for fresh fuel. (author). 16 refs., 5 tabs.

  9. Void distributions in liquid BiBr{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Maruyama, K [Faculty of Science, Niigata University, Niigata 950-2181 (Japan); Endo, H [Faculty of Science, Kyoto University, Kyoto 606-8224 (Japan); Hoshino, H [Faculty of Education, Hirosaki University, Hirosaki 036-8560 (Japan); Kawakita, Y [Faculty of Sciences, Kyushu University, Fukuoka 810-8560 (Japan); Kohara, S; Itou, M [Japan Synchrotron Radiation Research Institute(JASRI), Sayo-cho 679-5198 (Japan)

    2008-02-15

    The X-ray diffraction experiments and the reverse Monte Carlo analysis for liquid BiBr{sub 3} have been performed to clarify the distribution of Bi and Br ions around voids, comparing with previous results derived in the neutron diffraction experiments. The hexagonal cages involving voids are formed by the corner-sharing of the trigonal pyramidal BiBr{sub 3} blocks. The neighboring cages are linked together in highly correlated fashion. The observed pre-peak in S(Q) at 1.3A{sup -1} is related to the pre-peak of the void-based S'{sub CC} (Q) due to an intermediate chemical order in the structure. The pre-peak intensity increases with increasing temperature. This characteristic change for the pre-peak intensity is discussed by considering the modifications of the topology and stacking in the hexagonal cages.

  10. A DRAGON-MCNP comparison of void reactivity calculations

    International Nuclear Information System (INIS)

    Marleau, G.

    1995-01-01

    The determination of the reactivity coefficients associated with coolant voiding in a CANDU reactor is a subject which has attracted a large amount of interest in the last few years both from the theoretical and experimental point of view. One expects that deterministic codes such as DRAGON and WIMS-AECL or the MCNP4 Monte Carlo code should be able to adequately simulate the cell behaviour upon coolant voiding. However, the absence of an experimental database at equilibrium and discharge burnups has not permitted the full validation of any of these lattice codes, although a partial validation through comparison of two different computer codes has been considered. Here we present a comparison between DRAGON and MCNP4 of the void reactivity evaluation for fresh fuel. (author). 16 refs., 5 tabs

  11. Two-dimensional void reconstruction by neutron transmission

    International Nuclear Information System (INIS)

    Zakaib, G.D.; Harms, A.A.; Vlachopoulos, J.

    1978-01-01

    Contemporary algebraic reconstruction methods are utilized in investigating the two-dimensional void distribution in a water analog from neutron transmission measurements. It is sought to ultimately apply these techniques to the determination of time-averaged void distribution in two-phase flow systems as well as for potential usage in neutron radiography. Initially, projection data were obtained from a digitized model of a hypothetical two-phase representation and later from neutron beam traverses across a voided methacrylate plastic model. From 10 to 15 views were incorporated, and decoupling of overlapped measurements was utilized to afford greater resolution. In general, the additive Algebraic Reconstruction Technique yielded the best reconstructions, with others showing promise for noisy data. Results indicate the need for some further development of the method in interpreting real data

  12. Voiding patterns in men evaluated by a questionnaire survey

    DEFF Research Database (Denmark)

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

    1990-01-01

    A questionnaire on obstructive and irritative voiding symptoms was sent to 572 men aged between 20 and 79 years, selected at random from the National Register; 337 questionnaires were completed. None of the responders had consulted a doctor because of voiding symptoms. There was a significant...... voiding symptoms in men aged 60 to 79 years without subjective prostatism was the same as in patients admitted with prostatism, although most of the men had milder symptoms. Only nocturia and urge incontinence were more prevalent in patients admitted with prostatism. About 20% of men in the oldest decades...... 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....

  13. Noninvasive Medical Tools for Evaluating Voiding Pattern in Real Life

    Directory of Open Access Journals (Sweden)

    Kwonsoo Chun

    2017-04-01

    Full Text Available Voiding dysfunction is a common disease that contributes to a lower quality of life and has an increased prevalence in the elderly population. Noninvasive and objective methods such as uroflowmetry (UFM and voiding diaries (VDs are essential for exact diagnosis and effective treatment of this condition because patients with different causes of voiding dysfunction can complain of the same lower urinary tract symptoms. Further, different treatment options can be determined based on the diagnosis made from these symptoms. In order to improve the quality of UFM and VDs and to provide a convenient testing environment, several advances have been made by previous investigators. In this study, we investigate the history and technological mechanisms of UFM and VDs. We also aim to review UFM from the viewpoint of clinical and at-home uses, including the recently proposed toilet-shaped UFM and electronic VDs.

  14. Loss of urinary voiding sensation due to herpes zoster.

    Science.gov (United States)

    Hiraga, Akiyuki; Nagumo, Kiyomi; Sakakibara, Ryuji; Kojima, Shigeyuki; Fujinawa, Naoto; Hashimoto, Tasuku

    2003-01-01

    A case of sacral herpes zoster infection in a 56-year-old man with the complication of loss of urinary voiding sensation is presented. He had typical herpes zoster eruption on the left S2 dermatome, hypalgesia of the S1-S4 dermatomes, and absence of urinary voiding sensation. There was no other urinary symptom at the first medical examination. Urinary complications associated with herpes zoster are uncommon, but two types, acute cystitis and acute retention, have been recognized. No cases of loss of urinary voiding sensation due to herpes zoster have been reported. In this case, hypalgesia of the sacral dermatomes was mild compared to the marked loss of urethral sensation. This inconsistency is explained by the hypothesis that the number of urethral fibers is very small as compared to that of cutaneous fibers, therefore, urethral sensation would be more severely disturbed than cutaneous sensation. Copyright 2003 Wiley-Liss, Inc.

  15. Effects of two-phase mixing and void drift models on subchannel void fraction predictions in vertical bundles

    Energy Technology Data Exchange (ETDEWEB)

    Leung, K.H. [McMaster Univ., Hamilton, Ontario (Canada)], E-mail: leungk4@mcmaster.ca

    2009-07-01

    The evaluation of the subchannel code ASSERT against the OECD/NEA BFBT benchmark data demonstrated that at low pressures, the void fraction in the corner and side subchannels of a vertical bundle was over-predicted. Preliminary results suggest that this was due to the use of Carlucci's empirical correlation for void drift beyond its applicable range of pressure. Further examination indicates that the choice of the mixing and void drift models has a negligible effect on the error of the subchannel void fraction predictions. A single, isolated subchannel was simulated and results suggest that the root cause behind the over-prediction is inadequate mixing at the sides and corners of the bundle. Increasing the magnitude of the void drift coefficients in Carlucci's model at low pressure was found to improve the overall accuracy of the predictions. A simple correlation relating {omega} to the outlet pressure was found to increase the number of points falling within experimental error by 1.0%. (author)

  16. Effects of two-phase mixing and void drift models on subchannel void fraction predictions in vertical bundles

    International Nuclear Information System (INIS)

    Leung, K.H.

    2009-01-01

    The evaluation of the subchannel code ASSERT against the OECD/NEA BFBT benchmark data demonstrated that at low pressures, the void fraction in the corner and side subchannels of a vertical bundle was over-predicted. Preliminary results suggest that this was due to the use of Carlucci's empirical correlation for void drift beyond its applicable range of pressure. Further examination indicates that the choice of the mixing and void drift models has a negligible effect on the error of the subchannel void fraction predictions. A single, isolated subchannel was simulated and results suggest that the root cause behind the over-prediction is inadequate mixing at the sides and corners of the bundle. Increasing the magnitude of the void drift coefficients in Carlucci's model at low pressure was found to improve the overall accuracy of the predictions. A simple correlation relating Ω to the outlet pressure was found to increase the number of points falling within experimental error by 1.0%. (author)

  17. Effects of Void Uncertainties on Pin Power Distributions and the Void Reactivity Coefficient for a 10X10 BWR Assembly

    International Nuclear Information System (INIS)

    Jatuff, F.; Krouthen, J.; Helmersson, S.; Chawla, R.

    2004-01-01

    A significant source of uncertainty in Boiling Water Reactor physics is associated with the precise characterisation of the axially-dependent neutron moderation properties of the coolant inside the fuel assembly channel, and the corresponding effects on reactor physics parameters such as the lattice neutron multiplication, the neutron migration length, and the pin-by-pin power distribution. In this paper, the effects of particularly relevant void fraction uncertainties on reactor physics parameters have been studied for a BWR assembly of type Westinghouse SVEA-96 using the CASMO-4, HELIOS/PRESTO-2 and MCNP4C codes. The SVEA-96 geometry is characterised by the sub-division of the assembly into four different sub-bundles by means of an inner bypass with a cruciform shape. The study has covered the following issues: (a) the effects of different cross-section data libraries on the void coefficient of reactivity, for a wide range of void fractions; (b) the effects due to a heterogeneous vs. homogeneous void distribution inside the sub-bundles; and (c) the consequences of partly inserted absorber blades producing different void fractions in different sub-bundles. (author)

  18. Maximum entropy methods

    International Nuclear Information System (INIS)

    Ponman, T.J.

    1984-01-01

    For some years now two different expressions have been in use for maximum entropy image restoration and there has been some controversy over which one is appropriate for a given problem. Here two further entropies are presented and it is argued that there is no single correct algorithm. The properties of the four different methods are compared using simple 1D simulations with a view to showing how they can be used together to gain as much information as possible about the original object. (orig.)

  19. Effects contributing to positive coolant void reactivity in CANDU

    International Nuclear Information System (INIS)

    Whitlock, J.J.; Garland, W.J.; Milgram, M.S.

    1995-01-01

    The lattice cell code WIMS-AECL (Ref. 3) is used to model a typical CANDU lattice cell, using nominal geometric bucklings, the PIJ option, and 69-group Winfrith library. The effect of cell voiding is modeled as a 100% instantaneous removal of coolant from the lattice. This is conservative because of the neglect of time dependence and partial core voiding, considered more plausible in CANDU. Results are grouped into three spectral groups: fast neutrons (0.821 to 10 MeV), epithermal neutrons (0.625 eV to 0.821 MeV), and thermal neutrons (<0.625 eV)

  20. Supernovae observations in a 'meatball' universe with a local void

    International Nuclear Information System (INIS)

    Kainulainen, Kimmo; Marra, Valerio

    2009-01-01

    We study the impact of cosmic inhomogeneities on the interpretation of observations. We build an inhomogeneous universe model without dark energy that can confront supernova data and yet is reasonably well compatible with the Copernican principle. Our model combines a relatively small local void, that gives apparent acceleration at low redshifts, with a meatball model that gives sizable lensing (dimming) at high redshifts. Together these two elements, which focus on different effects of voids on the data, allow the model to mimic the concordance model.

  1. Supernovae observations in a 'meatball' universe with a local void

    Energy Technology Data Exchange (ETDEWEB)

    Kainulainen, Kimmo; Marra, Valerio [Department of Physics, University of Jyvaeskylae, PL 35 (YFL), FIN-40014 Jyvaeskylae, Finland and Helsinki Institute of Physics, University of Helsinki, PL 64, FIN-00014 Helsinki (Finland)

    2009-12-15

    We study the impact of cosmic inhomogeneities on the interpretation of observations. We build an inhomogeneous universe model without dark energy that can confront supernova data and yet is reasonably well compatible with the Copernican principle. Our model combines a relatively small local void, that gives apparent acceleration at low redshifts, with a meatball model that gives sizable lensing (dimming) at high redshifts. Together these two elements, which focus on different effects of voids on the data, allow the model to mimic the concordance model.

  2. Supernovae observations in a ``meatball'' universe with a local void

    Science.gov (United States)

    Kainulainen, Kimmo; Marra, Valerio

    2009-12-01

    We study the impact of cosmic inhomogeneities on the interpretation of observations. We build an inhomogeneous universe model without dark energy that can confront supernova data and yet is reasonably well compatible with the Copernican principle. Our model combines a relatively small local void, that gives apparent acceleration at low redshifts, with a meatball model that gives sizable lensing (dimming) at high redshifts. Together these two elements, which focus on different effects of voids on the data, allow the model to mimic the concordance model.

  3. Cluster-void degeneracy breaking: Modified gravity in the balance

    Science.gov (United States)

    Sahlén, Martin; Silk, Joseph

    2018-05-01

    Combining galaxy cluster and void abundances is a novel, powerful way to constrain deviations from general relativity and the Λ CDM model. For a flat w CDM model with growth of large-scale structure parametrized by the redshift-dependent growth index γ (z )=γ0+γ1z /(1 +z ) of linear matter perturbations, combining void and cluster abundances in future surveys with Euclid and the four-meter multiobject spectroscopic telescope could improve the figure of merit for (w ,γ0,γ1) by a factor of 20 compared to individual abundances. In an ideal case, improvement on current cosmological data is a figure of merit factor 600 or more.

  4. Void redistribution in sand under post-earthquake loading

    International Nuclear Information System (INIS)

    Boulanger, R.W.; Truman, S.P.

    1996-01-01

    A mechanism for void redistribution in an infinite slope under post-earthquake loading conditions is described by consideration of the in situ loading paths that can occur under post-earthquake conditions and the results of triaxial tests designed to represent specific in situ post-earthquake loading paths. The mechanism is illustrated by application to an example problem. Void redistribution is shown to be a phenomena that may be more pronounced at the field scale than at the laboratory scale. (author). 12 refs., 4 figs

  5. Influence of void on image quality of industrial SPECT

    International Nuclear Information System (INIS)

    Park, J G; Jung, S H; Kim, J B; Moon, J; Kim, C H

    2013-01-01

    Industrial single photon emission computed tomography (SPECT) is a promising technique to determine the dynamic behavior of industrial process media and has been developed in the Korea Atomic Energy Research Institute. The present study evaluated the influence of a void, which is presence in multiphase reactors of industrial process, on the image quality of an industrial SPECT. The results are very encouraging; that is, the performance of the industrial SPECT system is little influenced by the presence of a void, which means that industrial SPECT is an appropriate tool to estimate the dynamic characteristics of the process media in a water-air phase bubble column with a static gas sparger

  6. Transient void fraction measurements in rod bundle geometries

    International Nuclear Information System (INIS)

    Chan, A.M.C.

    1998-01-01

    A new gamma densitometer with a Ba-133 source and a Nal(TI) scintillator operated in the count mode has been designed for transient void fraction measurements in the RD-14M heated channels containing a seven-element heater bundle. The device was calibrated dynamically in the laboratory using an air-water flow loop. The void fraction measured was found to compare well with values obtained using the trapped-water method. The device was also found to follow very well the passage of air slugs in pulsating flow with slug passing frequencies of up to about 1.5 hz. (author)

  7. Void swelling behaviour of austenitic stainless steel during electron irradiation

    International Nuclear Information System (INIS)

    Sheng Zhongqi; Xiao Hong; Peng Feng; Ti Zhongxin

    1994-04-01

    The irradiation swelling behaviour of 00Cr17Ni14Mo2 austenitic stainless steel (AISI 316L) was investigated by means of high voltage electron microscope. Results showed that in solution annealed condition almost no swelling incubation period existed, and the swelling shifted from the transition period to the steady-state one when the displacement damage was around 40 dpa. In cold rolled condition there was evidently incubation period, and when the displacement damage was up to 84 dpa the swelling still remained in the transition period. The average size and density of voids in both conditions were measured, and the factors, which influenced the void swelling, were discussed. (3 figs.)

  8. Radiation Dose from Voiding Cystourethrography (VCUG) Examination in Children

    International Nuclear Information System (INIS)

    Siriwiladluk, T.; Krisanachinda, A.

    2012-01-01

    Introduction: The purpose of this study is to determine entrance skin dose (ESD) from fluoroscopy and radiography procedures in voiding cystourethrography (VCUG) studies of pediatric patients by dose-area product (DAP) recording. Methods: Radiation doses received by 70 patients underwent VCUG procedures were determined by the DAP Meter, Wellh?fer Dosimetrie GmbH, Germany) directly coupled to the x-ray tube window (Philips Omni Diagnost Eleva) and an electrometer connected to a computer for data collection. The study revealed the radiation dose for VCUG and the baseline data on the entrance skin dose, ESD, dose area-product (DAP) and the effective dose, E, to establish local reference dose levels for VCUG in pediatric patients. Results: The mean(minimum-maximum) ESD, DAP and the effective dose of pediatric patients in 4 age ranges were 3.41(1-9) mGy, 46.58 (21.90-158.90) cGycm 2 and 0.10(0.05-0.33) mSv for 0- 1 years, 6.80(2-16) mGy, 115.55 (20.70-258.70)cGycm 2 and 0.24(0.04-0.54) mSv for >1-5 years, 11.76 (3-23) mGy, 292.28 (88.90-593.50)cGycm 2 and 0.61(0.19-1.25) mSv for >5-10 years, and 20.50(10-42) mGy, 575.98(255.60-1247.80) cGycm 2 and 1.12(0.54-2.62) mSv for >10-15 years respectively. Discussion: The dose levels for VCUG as recommended by the national reference doses (NRDs) of UK are classified at patient age of 0-1 years, 90 cGy.cm 2 , >1-5 years, 110 cGy.cm 2 , >5-10 years, 210 cGy.cm 2 and >10-15 years, 470 cGy.cm 2 respectively. Conclusions: The mean DAP of pediatric patients were higher than the dose level as recommended by NRD at the age range >1-5, >5-10 and >10-15 years. The limitation in this study was the non uniform in the number of patients at the higher age. Attempts could be made to lower the radiation dose to avoid the higher risk of developing radiation-induced cancer in children. (author)

  9. The last glacial maximum

    Science.gov (United States)

    Clark, P.U.; Dyke, A.S.; Shakun, J.D.; Carlson, A.E.; Clark, J.; Wohlfarth, B.; Mitrovica, J.X.; Hostetler, S.W.; McCabe, A.M.

    2009-01-01

    We used 5704 14C, 10Be, and 3He ages that span the interval from 10,000 to 50,000 years ago (10 to 50 ka) to constrain the timing of the Last Glacial Maximum (LGM) in terms of global ice-sheet and mountain-glacier extent. Growth of the ice sheets to their maximum positions occurred between 33.0 and 26.5 ka in response to climate forcing from decreases in northern summer insolation, tropical Pacific sea surface temperatures, and atmospheric CO2. Nearly all ice sheets were at their LGM positions from 26.5 ka to 19 to 20 ka, corresponding to minima in these forcings. The onset of Northern Hemisphere deglaciation 19 to 20 ka was induced by an increase in northern summer insolation, providing the source for an abrupt rise in sea level. The onset of deglaciation of the West Antarctic Ice Sheet occurred between 14 and 15 ka, consistent with evidence that this was the primary source for an abrupt rise in sea level ???14.5 ka.

  10. Measurement of void swelling in thick non-uniformly irradiated 304 stainless steel blocks using nondestructive ultrasonic techniques

    International Nuclear Information System (INIS)

    Garner, F.A.; Okita, T.; Isobe, Y.; Etoh, J.; Sagisaka, M.; Matsunaga, T.; Freyer, P.D.; Huang, Y.; Wiezorek, J.M.K.; Porter, D.L.

    2015-01-01

    Void swelling is of potential importance in PWR austenitic internals, especially in components that will see higher doses during plant lives beyond 40 years. Proactive surveillance of void swelling is required to identify its emergence before swelling reaches levels that cause high levels of embrittlement and distortion. Non-destructive measurements of ultrasonic velocity can measure swelling at fractions of a percent. To demonstrate the feasibility of this technique for PWR application we have investigated five blocks of 304 stainless steel that were irradiated in the EBR-II fast reactor. These blocks were of hexagonal cross-section, with thickness of about 50 mm and lengths of about 218-245 mm. They were subjected to significant axial and radial gradients in gamma heating, temperature and dpa rate, producing complex internal distributions of swelling, reaching about 3.5% maximum at an off-center mid-core position. Swelling decreases both the density and the elastic moduli, thereby impacting the ultrasonic velocity. Concurrently, carbide precipitates form, producing increases in density and decreases in elastic moduli. Using blocks from both low and high dpa levels it was possible to separate the ultrasonic contributions of voids and carbides. Time-of-flight ultrasonic measurements were used to non-destructively measure the internal distribution of void swelling. These distributions were confirmed using non-destructive profilometry followed by destructive cutting to provide density change and electron microscopy data. It was demonstrated that the four measurement types produce remarkably consistent results. Therefore ultrasonic measurements offer great promise for in-situ surveillance of voids in PWR core internals. (authors)

  11. 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.

  12. Maximum Entropy Fundamentals

    Directory of Open Access Journals (Sweden)

    F. Topsøe

    2001-09-01

    Full Text Available Abstract: In its modern formulation, the Maximum Entropy Principle was promoted by E.T. Jaynes, starting in the mid-fifties. The principle dictates that one should look for a distribution, consistent with available information, which maximizes the entropy. However, this principle focuses only on distributions and it appears advantageous to bring information theoretical thinking more prominently into play by also focusing on the "observer" and on coding. This view was brought forward by the second named author in the late seventies and is the view we will follow-up on here. It leads to the consideration of a certain game, the Code Length Game and, via standard game theoretical thinking, to a principle of Game Theoretical Equilibrium. This principle is more basic than the Maximum Entropy Principle in the sense that the search for one type of optimal strategies in the Code Length Game translates directly into the search for distributions with maximum entropy. In the present paper we offer a self-contained and comprehensive treatment of fundamentals of both principles mentioned, based on a study of the Code Length Game. Though new concepts and results are presented, the reading should be instructional and accessible to a rather wide audience, at least if certain mathematical details are left aside at a rst reading. The most frequently studied instance of entropy maximization pertains to the Mean Energy Model which involves a moment constraint related to a given function, here taken to represent "energy". This type of application is very well known from the literature with hundreds of applications pertaining to several different elds and will also here serve as important illustration of the theory. But our approach reaches further, especially regarding the study of continuity properties of the entropy function, and this leads to new results which allow a discussion of models with so-called entropy loss. These results have tempted us to speculate over

  13. Evaluation Methodology for Void Swelling Susceptibility of APR1400 Reactor Vessel Internals for U.S. NRC Design Certification

    Energy Technology Data Exchange (ETDEWEB)

    Kweon, Hyeong Do; Lee, Do Hwan [KHNP CRI, Daejeon (Korea, Republic of)

    2016-10-15

    The APR1400 RVI (Reactor Vessel Internals) operates in harsh conditions, such as long term exposure to neutron irradiation, high temperatures, reactor coolant environment, and other operating loads. Therefore, even though the RVI components are mainly made of austenitic stainless steel which is well known to have good mechanical and corrosion-resistive properties, these operating conditions. The aging is characterized by a chromium depletion along grain boundaries of austenitic stainless steel, a decrease in ductility and fracture toughness of the steel, an increase in yield and ultimate strength of the steel, and a potential volume change due to void formation in the steel. For these reasons, under certain conditions of stress, temperature, and level of irradiation, the void swelling which is one of the challenging degradation mechanisms affecting the integrity of the RVI may appear at specific locations of the RVI, especially due to high neutron fluence and high temperature under localized gamma heating and low velocity of coolant flow. To assess the effects of operating neutron fluences, temperatures and stresses on the material properties changes and the susceptibility to the void swelling, the evaluation methodology of the APR1400 RVI components for U.S. NRC Design Certification was suggested in this paper. The approach to the evaluation is summarized as follows: 1. RVI component list of the APR1400 is collected. 2. Initial screening to determine the evaluation scope is completed using the design values of fluences. 3. Functionality assessments (radiation transport analysis, CFD analysis, structural analysis) are sequentially performed. 4. Susceptibility to the void swelling is identified through ANSYS/USERMAT module. KHNP believes that the proposed methodology which is based on the EPRI works for operating reactors is the best way to evaluate the void swelling for new reactors such as the APR1400.

  14. Probable maximum flood control

    International Nuclear Information System (INIS)

    DeGabriele, C.E.; Wu, C.L.

    1991-11-01

    This study proposes preliminary design concepts to protect the waste-handling facilities and all shaft and ramp entries to the underground from the probable maximum flood (PMF) in the current design configuration for the proposed Nevada Nuclear Waste Storage Investigation (NNWSI) repository protection provisions were furnished by the United States Bureau of Reclamation (USSR) or developed from USSR data. Proposed flood protection provisions include site grading, drainage channels, and diversion dikes. Figures are provided to show these proposed flood protection provisions at each area investigated. These areas are the central surface facilities (including the waste-handling building and waste treatment building), tuff ramp portal, waste ramp portal, men-and-materials shaft, emplacement exhaust shaft, and exploratory shafts facility

  15. Introduction to maximum entropy

    International Nuclear Information System (INIS)

    Sivia, D.S.

    1988-01-01

    The maximum entropy (MaxEnt) principle has been successfully used in image reconstruction in a wide variety of fields. We review the need for such methods in data analysis and show, by use of a very simple example, why MaxEnt is to be preferred over other regularizing functions. This leads to a more general interpretation of the MaxEnt method, and its use is illustrated with several different examples. Practical difficulties with non-linear problems still remain, this being highlighted by the notorious phase problem in crystallography. We conclude with an example from neutron scattering, using data from a filter difference spectrometer to contrast MaxEnt with a conventional deconvolution. 12 refs., 8 figs., 1 tab

  16. Solar maximum observatory

    International Nuclear Information System (INIS)

    Rust, D.M.

    1984-01-01

    The successful retrieval and repair of the Solar Maximum Mission (SMM) satellite by Shuttle astronauts in April 1984 permitted continuance of solar flare observations that began in 1980. The SMM carries a soft X ray polychromator, gamma ray, UV and hard X ray imaging spectrometers, a coronagraph/polarimeter and particle counters. The data gathered thus far indicated that electrical potentials of 25 MeV develop in flares within 2 sec of onset. X ray data show that flares are composed of compressed magnetic loops that have come too close together. Other data have been taken on mass ejection, impacts of electron beams and conduction fronts with the chromosphere and changes in the solar radiant flux due to sunspots. 13 references

  17. Introduction to maximum entropy

    International Nuclear Information System (INIS)

    Sivia, D.S.

    1989-01-01

    The maximum entropy (MaxEnt) principle has been successfully used in image reconstruction in a wide variety of fields. The author reviews the need for such methods in data analysis and shows, by use of a very simple example, why MaxEnt is to be preferred over other regularizing functions. This leads to a more general interpretation of the MaxEnt method, and its use is illustrated with several different examples. Practical difficulties with non-linear problems still remain, this being highlighted by the notorious phase problem in crystallography. He concludes with an example from neutron scattering, using data from a filter difference spectrometer to contrast MaxEnt with a conventional deconvolution. 12 refs., 8 figs., 1 tab

  18. Functional Maximum Autocorrelation Factors

    DEFF Research Database (Denmark)

    Larsen, Rasmus; Nielsen, Allan Aasbjerg

    2005-01-01

    MAF outperforms the functional PCA in concentrating the interesting' spectra/shape variation in one end of the eigenvalue spectrum and allows for easier interpretation of effects. Conclusions. Functional MAF analysis is a useful methods for extracting low dimensional models of temporally or spatially......Purpose. We aim at data where samples of an underlying function are observed in a spatial or temporal layout. Examples of underlying functions are reflectance spectra and biological shapes. We apply functional models based on smoothing splines and generalize the functional PCA in......\\verb+~+\\$\\backslash\\$cite{ramsay97} to functional maximum autocorrelation factors (MAF)\\verb+~+\\$\\backslash\\$cite{switzer85,larsen2001d}. We apply the method to biological shapes as well as reflectance spectra. {\\$\\backslash\\$bf Methods}. MAF seeks linear combination of the original variables that maximize autocorrelation between...

  19. Regularized maximum correntropy machine

    KAUST Repository

    Wang, Jim Jing-Yan; Wang, Yunji; Jing, Bing-Yi; Gao, Xin

    2015-01-01

    In this paper we investigate the usage of regularized correntropy framework for learning of classifiers from noisy labels. The class label predictors learned by minimizing transitional loss functions are sensitive to the noisy and outlying labels of training samples, because the transitional loss functions are equally applied to all the samples. To solve this problem, we propose to learn the class label predictors by maximizing the correntropy between the predicted labels and the true labels of the training samples, under the regularized Maximum Correntropy Criteria (MCC) framework. Moreover, we regularize the predictor parameter to control the complexity of the predictor. The learning problem is formulated by an objective function considering the parameter regularization and MCC simultaneously. By optimizing the objective function alternately, we develop a novel predictor learning algorithm. The experiments on two challenging pattern classification tasks show that it significantly outperforms the machines with transitional loss functions.

  20. Regularized maximum correntropy machine

    KAUST Repository

    Wang, Jim Jing-Yan

    2015-02-12

    In this paper we investigate the usage of regularized correntropy framework for learning of classifiers from noisy labels. The class label predictors learned by minimizing transitional loss functions are sensitive to the noisy and outlying labels of training samples, because the transitional loss functions are equally applied to all the samples. To solve this problem, we propose to learn the class label predictors by maximizing the correntropy between the predicted labels and the true labels of the training samples, under the regularized Maximum Correntropy Criteria (MCC) framework. Moreover, we regularize the predictor parameter to control the complexity of the predictor. The learning problem is formulated by an objective function considering the parameter regularization and MCC simultaneously. By optimizing the objective function alternately, we develop a novel predictor learning algorithm. The experiments on two challenging pattern classification tasks show that it significantly outperforms the machines with transitional loss functions.

  1. Effect of the critical size of initial voids on stress-induced migration

    International Nuclear Information System (INIS)

    Aoyagi, Minoru

    2004-01-01

    The stress-induced migration phenomenon is one of the problems related to the reliability of metal interconnections in semiconductor devices. This phenomenon causes voids and fractures in interconnections. The basic feature of this phenomenon is vacancy migration to minute initial voids. Expanding initial voids grow into larger voids and fractures. The purpose of this work is to theoretically clarify the effects of residual thermal stress and void surface stress on the behavior of the initial voids which exist immediately after a passivation process. Using a spherical metal sample with a spherical void under external stress, vacancy absorption or emission was investigated between the void surface and the sample surface. The behavior of vacancies and atoms was also investigated in interconnections under residual thermal stress. We show that the void or sample surface becomes a vacancy sink or source, depending on the mutual relationship between the surface stress due to the surface-free energy and the residual thermal stress. We also reveal that the initial voids, which exist immediately after a passivation process, grow into larger voids and fractures when the size of the initial voids exceeds the critical size. If the size of the initial void can be controlled to below the critical size, voids and fractures do not occur

  2. Void initiation from interfacial debonding of spherical silicon particles inside a silicon-copper nanocomposite: a molecular dynamics study

    Science.gov (United States)

    Cui, Yi; Chen, Zengtao

    2017-02-01

    Silicon particles with diameters from 1.9 nm to 30 nm are embedded in a face-centered-cubic copper matrix to form nanocomposite specimens for simulation. The interfacial debonding of silicon particles from the copper matrix and the subsequent growth of nucleated voids are studied via molecular dynamics (MD). The MD results are examined from several different perspectives. The overall mechanical performance is monitored by the average stress-strain response and the accumulated porosity. The ‘relatively farthest-traveled’ atoms are identified to characterize the onset of interfacial debonding. The relative displacement field is plotted to illustrate both subsequent interfacial debonding and the growth of a nucleated void facilitated by a dislocation network. Our results indicate that the initiation of interfacial debonding is due to the accumulated surface stress if the matrix is initially dislocation-free. However, pre-existing dislocations can make a considerable difference. In either case, the dislocation emission also contributes to the subsequent debonding process. As for the size effect, the debonding of relatively larger particles causes a drop in the stress-strain curve. The volume fraction of second-phase particles is found to be more influential than the size of the simulation box on the onset of interfacial debonding. The volume fraction of second-phase particles also affects the shape of the nucleated void and, therefore, influences the stress response of the composite.

  3. In situ determination of rheological properties and void fraction in Hanford Waste Tank 241-SY-101

    International Nuclear Information System (INIS)

    Stewart, C.W.; Shepard, C.L.; Alzheimer, J.M.; Stokes, T.I.; Terrones, G.

    1995-08-01

    This report presents the results of the operation of the void fraction instrument (VFI) and ball rheometer in Hanford Tank 241-SY-101, which contains approximately one million gallons of radioactive waste. These instruments provided the first direct assay of the waste condition in the tank after more than a year of mixer pump operation. The two instruments were deployed in the tank in late 1994 and early 1995 to gather much-needed data on the effect prolonged mixer pump operation has on gas retention in the waste. The information supplied by these instruments has filled a great gap in the quantitative knowledge of the waste condition. The results show that the solids are well-mixed by the current mixer pump to within less than a meter of the tank bottom. Undisturbed sludge remains only on the lowest 10--30 cm and contains 10--12% void. The mixed slurry above contains less than 1% void and has no measurable yield strength and a shear-thinning viscosity of approximately 6 Poise at 1 sec -1 . Estimating the gas volumes in each of the four layers based on VFI data yields a total of 221 ± 57 m 3 (7,800 ± 2,000 SCF) of gas at 1 atmosphere. Given the current waste level of 10.2 m (400 inches), the degassed waste level would be 9.8 m (386 inches). These results confirm that the mixer pump in Tank 241-SY-101 has performed the job it was installed to do--thoroughly mix the waste to release stored gas and prevent gas accumulation

  4. Atomic- and void-species nanostructures in chalcogenide glasses modified by high-energy γ-irradiation

    International Nuclear Information System (INIS)

    Kavetskyy, T.; Shpotyuk, O.; Kaban, I.; Hoyer, W.

    2007-01-01

    Atomic- and void-species nanostructures are studied in As 2 S 3 glass in unmodified and γ-modified states using a combination of conventional X-ray diffraction with respect to the first sharp diffraction peak, synchrotron-based high-energy X-ray diffraction and extended X-ray absorption fine structure spectroscopy. The experimental data are analyzed taking into account radiation-induced changes in the parameters of the first sharp diffraction peak (position, full width at half maximum, intensity), packing factor, structural disordering, atomic and void topology, coordination number and mean square deviation in bond length. The origin of the structural modification effect induced by γ-irradiation is explained in terms of coordination topological defects model. (authors)

  5. Nucleation of voids and other irradiation-produced defect aggregates

    International Nuclear Information System (INIS)

    Wiedersich, H.; Katz, J.L.

    1976-01-01

    The nucleation of defect clusters in crystalline solids from radiation-produced defects is different from the usual nucleation processes in one important aspect: the condensing defects, interstitial atoms and vacancies, can mutually annihilate and are thus similar to matter and antimatter. The nucleation process is described as the simultaneous reaction of vacancies and interstitials (and gas atoms if present) with embryos of all sizes. The reaction rates for acquisition of point defects (and gas atoms) are calculated from their respective jump frequencies and concentrations in the supersaturated system. The reaction rates for emission of point defects are derived from the free energies of the defect clusters in the thermodynamic equilibrium system, i.e., the system without excess point defects. This procedure differs from that used in conventional nucleation theory and permits the inclusion of the ''antimatter'' defect into the set of reaction-rate equations in a straightforward manner. The method is applied to steady-state nucleation, during irradiation, of both dislocation loops and voids in the absence and in the presence of immobile and mobile gas. The predictions of the nucleation theory are shown to be in qualitative agreement with experimental observations, e.g., void densities increase with increasing displacement rates; gases such as helium enhance void nucleation; at low displacement rates and at high temperatures the presence of gas is essential to void formation. For quantitative predictions, the theory must be extended to include the termination of nucleation

  6. Predictive efficacy of radioisotope voiding cystography for renal outcome

    International Nuclear Information System (INIS)

    Kim, Seok Ki; Lee, Dong Soo; Kim, Kwang Myeung; Choi, Whang; Chung, June Key; Lee, Myung Chul

    2000-01-01

    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.=20

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

    DEFF Research Database (Denmark)

    McAllister, Iain Wilson

    1992-01-01

    sustained in the void. However, the absolute value of this field is reduced with an increase in bulk permittivity. It is concluded that the present choice of a point charge to simulate the wall charge has the disadvantage that such a source is associated with a field singularity, and thus it is not possible...

  8. 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...

  9. Effect of main stream void distribution on cavitating hydrofoil

    International Nuclear Information System (INIS)

    Ito, J.

    1993-01-01

    For the safety analysis of a loss of coolant accident in a pressurized water reactor, it is important to establish an analytical method which predicts the pump performance under gas-liquid two-phase flow condition. J.H. Kim briefly reviewed several major two-phase flow pump models, and discussed the parameters that could significantly affect two-phase pump behavior. The parameter pointed out to be of the most importance is void distribution at the pump inlet. This says that the pipe bend near the pump inlet makes the void distribution at the pump inlet nonuniform, and this matter can have a significant effect on the impeller blade performance. This paper proposes an analytical method of solution for a partially cavitating hydrofoil placed in the main stream of incompressible homogeneous bubbly two-phase flow conditions whose void fraction is exponentially distributed normal to chordline. The paper clarifies the effect of main stream void distribution parameter on the partially cavitating hydrofoil characteristics

  10. The cosmic web in CosmoGrid void regions

    NARCIS (Netherlands)

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

    2016-01-01

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

  11. Monte Carlo validation of self shielding and void effect calculations

    International Nuclear Information System (INIS)

    Tellier, H.; Coste, M.; Raepsaet, C.; Soldevila, M.; Van der Gucht, C.

    1995-01-01

    The self shielding validation and the void effect are studied with Monte Carlo method. The satisfactory comparison obtained between the APOLLO 2 results of the self shielding effect and the TRIPOLI and MCNP results allows us to be confident in the multigroup transport code. (K.A.)

  12. Extrapolation of ZPR sodium void measurements to the power reactor

    International Nuclear Information System (INIS)

    Beck, C.L.; Collins, P.J.; Lineberry, M.J.; Grasseschi, G.L.

    1976-01-01

    Sodium-voiding measurements of ZPPR assemblies 2 and 5 are analyzed with ENDF/B Version IV data. Computations include directional diffusion coefficients to account for streaming effects resulting from the plate structure of the critical assembly. Bias factors for extrapolating critical assembly data to the CRBR design are derived from the results of this analysis

  13. Detection of Vesico-Ureteric Reflux Using Voiding Hippuran Ureterograms

    Energy Technology Data Exchange (ETDEWEB)

    Sutherland, J. B.; Palser, R. [Section of Nuclear Medicine, Manitoba Cancer Treatment and Research Foundation, Winnipeg General Hospital, Winnipeg (Canada); Macpherson, R. I. [Children' s Hospital of Winnipeg, Winnipeg (Canada)

    1971-02-15

    Initial results of a technique for the demonstration of vesico-ureteric reflux in children are described. Hippuran-{sup 131}I (15 {mu}Ci) (ortho-iodohippurate) is injected intravenously. A standard renogram is obtained. Additional collimation is added to the recording probes and they are positioned to record the radioactivity from the mid-ureteric region. Recordings of normal and abnormal peristaltic activity during per-ora hydration of the patient are thus obtained. When the child is willing to void, he is placed upright on a bed pan, the probes positioned to record over the lower ureteric region and recordings are made while the child voids. All data are recorded on a 512-channel analyser operated in the multi-scaler node. Data are punched out on paper tape and, after an 11 point computer smoothing program, are displayed graphically. These recordings show different patterns in normal children and those with vesico-ureteric reflux. There are several advantages to this technique over the standard radiological and other radionuclide voiding cystoureterograms. The results are compared with contrast voiding cystourethrograms in both normal children and those with vesico-ureteric reflux. (author)

  14. 3D optical tomography in the presence of void regions

    Science.gov (United States)

    Riley, J.; Dehghani, Hamid; Schweiger, Martin; Arridge, Simon R.; Ripoll, Jorge; Nieto-Vesperinas, Manuel

    2000-12-01

    We present an investigation of the effect of a 3D non-scattering gap region on image reconstruction in diffuse optical tomography. The void gap is modelled by the Radiosity-Diffusion method and the inverse problem is solved using the adjoint field method. The case of a sphere with concentric spherical gap is used as an example.

  15. 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)

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

    Indian Academy of Sciences (India)

    Unknown

    The strain hardening capacity has a marked effect on void size, and is an indicator of fracture .... a model of ductile failure based on the concept that the critical step in the .... Ashby M F, Gandhi C and Taplin D M R 1979 Acta Metal. 27. 699.

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

    International Nuclear Information System (INIS)

    Oliveira, Fernando L. de; Rocha, Marcelo S.

    2013-01-01

    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)

  18. Designing Si/porous-C composite with buffering voids as high capacity anode for lithium-ion batteries

    International Nuclear Information System (INIS)

    Yue, Lu; Zhang, Wenhui; Yang, Jingfeng; Zhang, Lingzhi

    2014-01-01

    A novel Si/porous-C composite with buffering voids was prepared by the co-assembly of phenol-formaldehyde resin, SiO 2 and Si nanoparticles, followed by a carbonizing process and subsequent removal of SiO 2 template. Si nanoparticle was coated with a layer of porous carbon shell with rationally designed void in between which provides the accommodating space for the volume change of Si over cycling. The as-prepared composite electrode exhibited good electrochemical performances as an anode material in lithium-ion cells, showing a stable reversible capacity of 980 mAh g −1 over 80 cycles with small capacity fade of 0.17%/cycle and high rate capability (721 mAh g −1 at 2000 mA g −1 )

  19. Void Measurements in the Regions of Sub-Cooled and Low-Quality Boiling. Part 1. Low Mass Velocities

    Energy Technology Data Exchange (ETDEWEB)

    Rouhani, S Z

    1966-07-15

    By the application of the ({gamma}, n) reaction to boiling heavy water, void volume fractions have been measured in a vertical annular channel with 25 mm O.D. and 12 mm I.D. at a heated length of 1090 mm. The experiments covered pressures from 10 to 50 bars, mass velocities from 50 to 1450 kg/m-sec, heat fluxes from 30 to 90 W/cm{sup 2}, sub coolings from 30 to 0 C, and steam qualities from 0 to 15 %. The results indicate noticeable effects of pressure, heat flux and even mass velocity upon the variations of void with subcooling and steam quality. A novel explanation of the mechanism of their effects has been found and proved by qualitative analysis.

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

    Science.gov (United States)

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

    2016-08-26

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

  1. Influence of second phase dispersion on void formation during irradiation

    International Nuclear Information System (INIS)

    Sundararaman, M.; Banerjee, S.; Krishnan, R.

    Irradiation-induced void formation in alloys has been found to be strongly influenced by the microstructure, the important microstructural parameters being the dislocation density and the nature, density and distribution of second-phase precipitates. The effects of various types of precipitates on void swelling have been examined using the generally-accepted model of void formation : void embryos are assumed to grow in a situation where equal numbers of vacancies and interstitials are continuously generated by the incident irradiation, the interstitials being somewhat perferentially absorbed in some sinks present in the material. The mechanism of the trapping of defects by a distribution of precipitates has been discussed and the available experimental results on the suppression of void formation in materials containing coherent precipitates have been reviewed. Experimental results on the microstructure developed in a nickel-base alloys, Inconel-718 (considered to be a candidate material for structural applications in fast reactors), have been presented. The method of determination of the coherency strain associated with the precipitates has been illustrated with the help of certain observations made on this alloy. The major difficulty in using a two-phase alloy in an irradiation environment is associated with the irradiation-induced instability of the precipitates. Several processes such as precipitate dislocation (in which the incident radiation removes the outer layer of precipitates by recoil), enhanced diffusion disordering, fragmentation of precipitates, etc. are responsible for bringinq about a significant change in the structure of a two-phase material during irradiation. The effect of these processes on the continued performance of a two-phase alloy subjected to irradiation at an elevated temperature has been discussed. (auth.)

  2. Solar maximum mission

    International Nuclear Information System (INIS)

    Ryan, J.

    1981-01-01

    By understanding the sun, astrophysicists hope to expand this knowledge to understanding other stars. To study the sun, NASA launched a satellite on February 14, 1980. The project is named the Solar Maximum Mission (SMM). The satellite conducted detailed observations of the sun in collaboration with other satellites and ground-based optical and radio observations until its failure 10 months into the mission. The main objective of the SMM was to investigate one aspect of solar activity: solar flares. A brief description of the flare mechanism is given. The SMM satellite was valuable in providing information on where and how a solar flare occurs. A sequence of photographs of a solar flare taken from SMM satellite shows how a solar flare develops in a particular layer of the solar atmosphere. Two flares especially suitable for detailed observations by a joint effort occurred on April 30 and May 21 of 1980. These flares and observations of the flares are discussed. Also discussed are significant discoveries made by individual experiments

  3. A simple capacitance sensor for void fraction measurement in gas-liquid two-phase flow

    International Nuclear Information System (INIS)

    Silva, Luiz C.R.P.; Faccini, José L.H.; Farias, Marcos S.; Su, Jian

    2017-01-01

    In this work we present a simple and inexpensive capacitance sensor for time averaging void fraction measurement of gas-liquid two-phase flow, which was developed at Experimental Thermal hydraulics Laboratory in the Nuclear Engineering Institute, IEN/CNEN. The sensor is a non-invasive device causing no flow disturbances. It is formed by two parallel plates and four electronic circuits: a signal input circuit, an amplification circuit, a frequency generator, and a power supply circuit. The frequency generator applies a sinusoidal signal with appropriate frequency into the signal input circuit which converts the capacitance variation value (or void fraction) of the two-phase flow into a voltage signal that goes to the amplifier stage; the output signal of the amplifier stage will be an input to an analogic/digital converter, installed inside of a computer, and it will provide interpretation of the signal behavior. The capacitance sensor was calibrated by using a horizontal acrylic tube filled with a known volume of water. (author)

  4. A simple capacitance sensor for void fraction measurement in gas-liquid two-phase flow

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Luiz C.R.P.; Faccini, José L.H.; Farias, Marcos S., E-mail: reina@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Su, Jian, E-mail: sujian@con.ufrj.br [Coordenacao de Pos-Graduacao e Pesquisa de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Instituto de Engenharia Nuclear

    2017-07-01

    In this work we present a simple and inexpensive capacitance sensor for time averaging void fraction measurement of gas-liquid two-phase flow, which was developed at Experimental Thermal hydraulics Laboratory in the Nuclear Engineering Institute, IEN/CNEN. The sensor is a non-invasive device causing no flow disturbances. It is formed by two parallel plates and four electronic circuits: a signal input circuit, an amplification circuit, a frequency generator, and a power supply circuit. The frequency generator applies a sinusoidal signal with appropriate frequency into the signal input circuit which converts the capacitance variation value (or void fraction) of the two-phase flow into a voltage signal that goes to the amplifier stage; the output signal of the amplifier stage will be an input to an analogic/digital converter, installed inside of a computer, and it will provide interpretation of the signal behavior. The capacitance sensor was calibrated by using a horizontal acrylic tube filled with a known volume of water. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-10-04

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

  6. 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.

  7. Maximum entropy and Bayesian methods

    International Nuclear Information System (INIS)

    Smith, C.R.; Erickson, G.J.; Neudorfer, P.O.

    1992-01-01

    Bayesian probability theory and Maximum Entropy methods are at the core of a new view of scientific inference. These 'new' ideas, along with the revolution in computational methods afforded by modern computers allow astronomers, electrical engineers, image processors of any type, NMR chemists and physicists, and anyone at all who has to deal with incomplete and noisy data, to take advantage of methods that, in the past, have been applied only in some areas of theoretical physics. The title workshops have been the focus of a group of researchers from many different fields, and this diversity is evident in this book. There are tutorial and theoretical papers, and applications in a very wide variety of fields. Almost any instance of dealing with incomplete and noisy data can be usefully treated by these methods, and many areas of theoretical research are being enhanced by the thoughtful application of Bayes' theorem. Contributions contained in this volume present a state-of-the-art overview that will be influential and useful for many years to come

  8. Constitutive modeling of void-growth-based tensile ductile failures with stress triaxiality effects

    KAUST Repository

    Mora Cordova, Angel; Liu, Jinxing; El Sayed, Tamer S.

    2014-01-01

    In most metals and alloys, the evolution of voids has been generally recognized as the basic failure mechanism. Furthermore, stress triaxiality has been found to influence void growth dramatically. Besides strain intensity, it is understood

  9. Mechanism of Void Prediction in Flip Chip Packages with Molded Underfill

    Science.gov (United States)

    Wu, Kuo-Tsai; Hwang, Sheng-Jye; Lee, Huei-Huang

    2017-08-01

    Voids have always been present using the molded underfill (MUF) package process, which is a problem that needs further investigation. In this study, the process was studied using the Moldex3D numerical analysis software. The effects of gas (air vent effect) on the overall melt front were also considered. In this isothermal process containing two fluids, the gas and melt colloid interact in the mold cavity. Simulation enabled an appropriate understanding of the actual situation to be gained, and, through analysis, the void region and exact location of voids were predicted. First, the global flow end area was observed to predict the void movement trend, and then the local flow ends were observed to predict the location and size of voids. In the MUF 518 case study, simulations predicted the void region as well as the location and size of the voids. The void phenomenon in a flip chip ball grid array underfill is discussed as part of the study.

  10. Void swelling in fast reactor irradiated high purity binary iron-chromium alloys

    International Nuclear Information System (INIS)

    Little, E.A.; Stow, D.A.

    The void swelling characteristics of a series of high purity binary iron-chromium alloys containing 0 - 615 0 C. The void swelling behaviour can be qualitatively rationalized in terms of point defect trapping and precipitation processes involving chromium atoms

  11. Effect of scale size, orientation type and dispensing method on void ...

    Indian Academy of Sciences (India)

    AIZAT ABAS

    2018-04-13

    Apr 13, 2018 ... reduce the formation of void during encapsulation process. Keywords. Ball grid ... Additionally, the usage of LBM to study of void in CUF was again conducted by ... models are fabricated using clear Perspex and plastics beads.

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

    KAUST Repository

    Elrasad, Amr; Shihada, Basem

    2015-01-01

    This work investigates void filling (idle periods) in long-reach Ethernet passive optical networks. We focus on reducing grant delays and hence reducing the average packet delay. We introduce a novel approach called parallel void thread (PVT), which

  13. Void fraction instrument software, Version 1,2, Acceptance test report

    International Nuclear Information System (INIS)

    Gimera, M.

    1995-01-01

    This provides the report for the void fraction instrument acceptance test software Version 1.2. The void fraction will collect data that will be used to calculate the quantity of gas trapped in waste tanks

  14. Are urine flow-volume nomograms developed on Caucasian men optimally applicable for Indian men? Need for appraisal of flow-volume relations in local population

    Directory of Open Access Journals (Sweden)

    Mayank M Agarwal

    2010-01-01

    Full Text Available Introduction : Flow-volume nomograms and volume-corrected flow-rates (cQ are tools to correct uroflow rates (Q with varied voided volumes (VV of urine. We investigated the applicability of the available nomograms in our local population. Materials and Methods : Raw data of our previous study on variation in Q with voiding position (standing, sitting, and squatting in healthy adult men was reanalyzed. Additionally, the departmental urodynamic database of the last four years was searched for uroflow data of men with voiding symptoms (International Prostatic Symptom Score (IPSS > 7 and global quality of life score >2. These results were projected on the Liverpool and Siroky nomograms for men. The Q-VV relations were statistically analyzed using curve-estimation regression method to examine the current definition of corrected maximum flow rate (Qmax. Results : We found a cubic relation between Q and VV; based on this we developed novel equation for cQ [cQ=Q/(VV 1/3 ] and novel confidence-limit flow-volume nomograms. The imaginary 16 th percentile line of Liverpool nomogram, -1 standard-deviation line of Siroky nomogram and lower 68% confidence-limit line of our nomogram had sensitivity of 96.2%, 100% and 89.3%, and specificity of 75.3% 69.3% and 86.0%, respectively for Qmax-VV relations. Corresponding values for average flow rate (Qave-volume relations were 96.2%, 100% and 94.6%, and 75.2%, 50.4% and 86.0%, respectively. The area under curve of the receiver operating characteristics (ROC curve for cQmax and cQave was 0.954 and 0.965, respectively, suggesting significantly higher discriminatory power than chance (P = 0.0001. Conclusion : Flow-volume nomograms developed on Caucasian population may not be optimally applicable to the Indian population. We introduce flow-volume nomograms and cQ, which have high sensitivity and specificity.

  15. Percolation through voids around overlapping spheres: A dynamically based finite-size scaling analysis

    Science.gov (United States)

    Priour, D. J.

    2014-01-01

    The percolation threshold for flow or conduction through voids surrounding randomly placed spheres is calculated. With large-scale Monte Carlo simulations, we give a rigorous continuum treatment to the geometry of the impenetrable spheres and the spaces between them. To properly exploit finite-size scaling, we examine multiple systems of differing sizes, with suitable averaging over disorder, and extrapolate to the thermodynamic limit. An order parameter based on the statistical sampling of stochastically driven dynamical excursions and amenable to finite-size scaling analysis is defined, calculated for various system sizes, and used to determine the critical volume fraction ϕc=0.0317±0.0004 and the correlation length exponent ν =0.92±0.05.

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

    KAUST Repository

    Liu, Jinxing; El Sayed, Tamer S.

    2012-01-01

    Micro-voids of varying sizes exist in most metals and alloys. Both experiments and numerical studies have demonstrated the critical influence of initial void sizes on void growth. The classical Gurson-Tvergaard-Needleman model summarizes

  17. Total meltwater volume since the Last Glacial Maximum and viscosity structure of Earth's mantle inferred from relative sea level changes at Barbados and Bonaparte Gulf and GIA-induced J˙2

    Science.gov (United States)

    Nakada, Masao; Okuno, Jun'ichi; Yokoyama, Yusuke

    2016-02-01

    Inference of globally averaged eustatic sea level (ESL) rise since the Last Glacial Maximum (LGM) highly depends on the interpretation of relative sea level (RSL) observations at Barbados and Bonaparte Gulf, Australia, which are sensitive to the viscosity structure of Earth's mantle. Here we examine the RSL changes at the LGM for Barbados and Bonaparte Gulf ({{RSL}}_{{L}}^{{{Bar}}} and {{RSL}}_{{L}}^{{{Bon}}}), differential RSL for both sites (Δ {{RSL}}_{{L}}^{{{Bar}},{{Bon}}}) and rate of change of degree-two harmonics of Earth's geopotential due to glacial isostatic adjustment (GIA) process (GIA-induced J˙2) to infer the ESL component and viscosity structure of Earth's mantle. Differential RSL, Δ {{RSL}}_{{L}}^{{{Bar}},{{Bon}}} and GIA-induced J˙2 are dominantly sensitive to the lower-mantle viscosity, and nearly insensitive to the upper-mantle rheological structure and GIA ice models with an ESL component of about (120-130) m. The comparison between the predicted and observationally derived Δ {{RSL}}_{{L}}^{{{Bar}},{{Bon}}} indicates the lower-mantle viscosity higher than ˜2 × 1022 Pa s, and the observationally derived GIA-induced J˙2 of -(6.0-6.5) × 10-11 yr-1 indicates two permissible solutions for the lower mantle, ˜1022 and (5-10) × 1022 Pa s. That is, the effective lower-mantle viscosity inferred from these two observational constraints is (5-10) × 1022 Pa s. The LGM RSL changes at both sites, {{RSL}}_{{L}}^{{{Bar}}} and {{RSL}}_{{L}}^{{{Bon}}}, are also sensitive to the ESL component and upper-mantle viscosity as well as the lower-mantle viscosity. The permissible upper-mantle viscosity increases with decreasing ESL component due to the sensitivity of the LGM sea level at Bonaparte Gulf ({{RSL}}_{{L}}^{{{Bon}}}) to the upper-mantle viscosity, and inferred upper-mantle viscosity for adopted lithospheric thicknesses of 65 and 100 km is (1-3) × 1020 Pa s for ESL˜130 m and (4-10) × 1020 Pa s for ESL˜125 m. The former solution of (1-3) × 1020

  18. Void swelling and segregation in dilute nickel alloys

    International Nuclear Information System (INIS)

    Potter, D.I.; Rehn, L.E.; Okamoto, P.R.; Wiedersich, H.

    1977-01-01

    Five binary alloys containing 1 at.% of Al, Ti, Mo, Si and Be in nickel were irradiated at temperatures from 525 to 675 0 C with 3.5-MeV 58 Ni + ions. The resultant microstructures were examined by TEM, and void diameters, number densities and swelling are presented for each alloy over the temperature interval investigated. A systematic relation between solute misfit (size factor) and void swelling is established for these alloys. Solute concentration profiles near the irradiated surface were determined and these also exhibited a systematic behavior--undersize solutes segregated to the surface, whereas oversize solutes were depleted. The results are consistent with calculations based on strong interstitial-solute trapping by undersize solutes and vacancy-solute trapping by oversize solutes that are weak interstitial traps

  19. 40 CFR 1065.525 - Engine starting, restarting, shutdown, and optional repeating of void discrete modes.

    Science.gov (United States)

    2010-07-01

    ..., and optional repeating of void discrete modes. 1065.525 Section 1065.525 Protection of Environment... repeating of void discrete modes. (a) Start the engine using one of the following methods: (1) Start the... during one of the modes of a discrete-mode test, you may void the results only for that individual mode...

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

    DEFF Research Database (Denmark)

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

    2017-01-01

    Void coalescence at severe shear deformation has been studied intensively under monotonic loading conditions, and the sequence of micro-mechanisms that governs failure has been demonstrated to involve collapse, rotation, and elongation of existing voids. Under intense shearing, the voids are flat...

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

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    2007-01-01

    of the ligaments between the crack-tip and a void or between voids involves the development of very large strains, which are included in the model by using remeshing at several stages of the plastic deformation. The material is here described by standard isotropic hardening Mises theory. For a very small void...

  2. 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....

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

    DEFF Research Database (Denmark)

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

    1988-01-01

    be drawn about the effects of the gas within the void as well as the size, shape, and location of voids. The method is illustrated by applying it to a spheroidal void in a simple disk-type gas-insulated-substation (GIS) spacer. It is found that the nonattaching gas generates an induced charge...

  4. Influence of void ratio on thermal performance of heat pipe receiver

    International Nuclear Information System (INIS)

    Gui Xiaohong; Tang Dawei; Liang Shiqiang; Lin Bin; Yuan Xiugan

    2012-01-01

    Highlights: ► The temperature gradient increases significantly and the utility ratio of PCM decreases obviously as void ratio increases. ► Void cavity influences the process of phase change greatly. ► PCM melts slowly during sunlight periods and freezes slowly during eclipse periods as void ratio increases. ► The temperature gradient of PCM zone is very significant with the effect of void cavity. - Abstract: In this paper, influence of void ratio on thermal performance of heat pipe receiver under microgravity is numerically simulated. Accordingly, mathematical model is set up. Numerical method is offered. The temperature field of Phase Change Material (PCM) canister is shown. Numerical results are compared with numerical ones of National Aeronautics and Space Administration (NASA). Numerical results show that the temperature gradient increases significantly and the utility ratio of PCM decreases obviously as void ratio increases. Void cavity influences the process of phase change greatly. PCM melts slowly during sunlight periods and freezes slowly during eclipse periods as void ratio increases. The thermal resistance of void cavity is much bigger than that of PCM canister wall. Void cavity prevents the heat transfer between PCM zone and canister wall. The temperature gradient of PCM zone is very significant with the effect of void cavity. So the thermal stress of heat pipe receiver may increase, and the lifetime may decrease as void ratio increases.

  5. Union operation image processing of data cubes separately processed by different objective filters and its application to void analysis in an all-solid-state lithium-ion battery.

    Science.gov (United States)

    Yamamoto, Yuta; Iriyama, Yasutoshi; Muto, Shunsuke

    2016-04-01

    In this article, we propose a smart image-analysis method suitable for extracting target features with hierarchical dimension from original data. The method was applied to three-dimensional volume data of an all-solid lithium-ion battery obtained by the automated sequential sample milling and imaging process using a focused ion beam/scanning electron microscope to investigate the spatial configuration of voids inside the battery. To automatically fully extract the shape and location of the voids, three types of filters were consecutively applied: a median blur filter to extract relatively larger voids, a morphological opening operation filter for small dot-shaped voids and a morphological closing operation filter for small voids with concave contrasts. Three data cubes separately processed by the above-mentioned filters were integrated by a union operation to the final unified volume data, which confirmed the correct extraction of the voids over the entire dimension contained in the original data. © The Author 2015. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  6. Void Formation during Diffusion - Two-Dimensional Approach

    Science.gov (United States)

    Wierzba, Bartek

    2016-06-01

    The final set of equations defining the interdiffusion process in solid state is presented. The model is supplemented by vacancy evolution equation. The competition between the Kirkendall shift, backstress effect and vacancy migration is considered. The proper diffusion flux based on the Nernst-Planck formula is proposed. As a result, the comparison of the experimental and calculated evolution of the void formation in the Fe-Pd diffusion couple is shown.

  7. Effect of helium on void swelling in vanadium

    International Nuclear Information System (INIS)

    Brimhall, J.L.; Simonen, E.P.

    1975-01-01

    Little difference in void microstructural swelling of vanadium is observed when helium is injected simultaneously with a 46- or 5-MeV nickel beam as compared to no helium injection, at least at high dose rates. At lower dose rates, a strong helium effect is seen when the helium is injected prior to heavy ion bombardment. The effect of the helium is shown to be a strong function of the overall displacement damage rate

  8. Influence of silicon on void nucleation in irradiated alloys

    International Nuclear Information System (INIS)

    Esmailzadeh, B.; Kumar, A.; Garner, F.A.

    1984-01-01

    The addition of silicon to pure nickel, Ni-Cr alloys and Fe-Ni-Cr alloys raises the diffusivity of each of the alloy components. The resultant increase in the effective vacancy diffusion coefficient causes large reductions in the nucleation rate of voids during irradiation. This extends the transient regime of swelling, which is controlled not only by the amount of silicon in solution but also by the precipitation kinetics of precipitates rich in nickel and silicon

  9. Theories of nucleation and growth of bubbles and voids

    International Nuclear Information System (INIS)

    Speight, M.V.

    1977-01-01

    The application of classical nucleation theory to the formation of voids from a supersaturated concentration of vacancies is reviewed. The effect of a dissolved concentration of barley soluble gas on the nucleation rate of voids is emphasized. Exposure to a damaging flux of irradiation is the most effective way of introducing a vacancy supersaturation, but interstitials are produced at an equal rate. The concentration of interstitials inhibits the nucleation of voids which can occur only in the presence of dislocations since they preferentially absorb interstitials. It is well known that a definite value of internal gas pressure is necessary to stabilize a bubble so that it shows no tendencies to either shrink or grow. The arguments are reviewed which conclude that this pressure is determined by the specific surface free energy of the solid rather than the surface tension. While the former property refers to the energy necessary to create new surface, the latter is a measure of the work done in elastically stretching a a given surface. The presence of an equilibrium gas bubble leaves the stresses in the surrounding solid unperturbed only when surface energy and surface tension are numerically equal. A bubble with internal pressure greater than the restraint offered by surface energy tends to grow to relieve the excess pressure. The mechanism of growth can involve the migration of vacancies from remote sources to the bubble surface or the plastic straining of the solid surrounding the bubble. The kinetics of both mechanisms are developed and compared. The theory of growth of grain-boundary voids by vacancy condensation under an applied stress is also considered. (author)

  10. A FACSIMILE code for calculating void swelling, version VS1

    International Nuclear Information System (INIS)

    Windsor, M.; Bullough, R.; Wood, M.H.

    1979-11-01

    VS1 is the first of a series of FACSIMILE codes that are being made available to predict the swelling of materials under irradiation at different temperatures, using chemical rate equations for the point defect losses to voids, interstitial loops, dislocation network, grain boundaries and foil surfaces. In this report the rate equations used in the program are given together with a detailed description of the code and directions for its use. (author)

  11. 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

  12. Study of Bubble Size, Void Fraction, and Mass Transport in a Bubble Column under High Amplitude Vibration

    Directory of Open Access Journals (Sweden)

    Shahrouz Mohagheghian

    2018-04-01

    Full Text Available Vertical vibration is known to cause bubble breakup, clustering and retardation in gas-liquid systems. In a bubble column, vibration increases the mass transfer ratio by increasing the residence time and phase interfacial area through introducing kinetic buoyancy force (Bjerknes effect and bubble breakup. Previous studies have explored the effect of vibration frequency (f, but minimal effort has focused on the effect of amplitude (A on mass transfer intensification. Thus, the current work experimentally examines bubble size, void fraction, and mass transfer in a bubble column under relatively high amplitude vibration (1.5 mm < A <9.5 mm over a frequency range of 7.5–22.5 Hz. Results of the present work were compared with past studies. The maximum stable bubble size under vibration was scaled using Hinze theory for breakage. Results of this work indicate that vibration frequency exhibits local maxima in both mass transfer and void fraction. Moreover, an optimum amplitude that is independent of vibration frequency was found for mass transfer enhancements. Finally, this work suggests physics-based models to predict void fraction and mass transfer in a vibrating bubble column.

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

    Energy Technology Data Exchange (ETDEWEB)

    Hamaus, Nico; Weller, Jochen [Universitäts-Sternwarte München, Fakultät für Physik, Ludwig-Maximilians Universität, Scheinerstr. 1, D-81679 München (Germany); Cousinou, Marie-Claude; Pisani, Alice; Aubert, Marie; Escoffier, Stéphanie, E-mail: hamaus@usm.lmu.de, E-mail: cousinou@cppm.in2p3.fr, E-mail: pisani@cppm.in2p3.fr, E-mail: maubert@cppm.in2p3.fr, E-mail: escoffier@cppm.in2p3.fr, E-mail: jochen.weller@usm.lmu.de [Aix Marseille Univ., CNRS/IN2P3, CPPM, 163 avenue de Luminy, F-13288, Marseille (France)

    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 {sup −1}Mpc. 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( z-bar =0.32)=0.599{sup +0.134}{sub −0.124} and β( z-bar =0.54)=0.457{sup +0.056}{sub −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 z-bar =0.32, which increases to 3σ when the data is restricted to the lowest available redshift range of 0.15< z <0.33.

  14. 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

  15. Void coefficient of reactivity calculation for AP-600 core

    International Nuclear Information System (INIS)

    Suparlina, L.; Budiono, T.A.; Mardha, A.; Tukiran

    1998-01-01

    Void coefficient of reactivity as one of reactor kinetics parameters has been carried out. The calculation was done into two steps which is cell calculation using WIMSD/4 and core calculation using Batan-2DIFF code programs with the condition of beginning of cycle with all fresh fuels elements and all control rods withdrawn. The one dimension transport program in four neutron energy groups is used to calculate the cell generation of various core materials cell has been calculated in 1/4 fuel element with cluster model and square pitch arrange. Moderator density have been reduced until 20% for the void coefficient of reactivity calculation. Macroscopic cross-section as the out put of WIMSD/4 is being used as the input at the diffusion neutron program for core calculation. The void coefficient of reactivity of the AP-600 core can be determined with regular neutron flux and adjoint in four energy groups and X-Y geometry. The results is shown that the K eff calculation value is different 5.2% from the design data

  16. Pelvic floor spasm as a cause of voiding dysfunction.

    Science.gov (United States)

    Kuo, Tricia L C; Ng, L G; Chapple, Christopher R

    2015-07-01

    Pelvic floor disorders can present with lower urinary tract symptoms, bowel, sexual dysfunction, and/or pain. Symptoms of pelvic muscle spasm (nonrelaxing pelvic floor or hypertonicity) vary and can be difficult to recognize. This makes diagnosis and management of these disorders challenging. In this article, we review the current evidence on pelvic floor spasm and its association with voiding dysfunction. To distinguish between the different causes of voiding dysfunction, a video urodynamics study and/or electromyography is often required. Conservative measures include patient education, behavioral modifications, lifestyle changes, and pelvic floor rehabilitation/physical therapy. Disease-specific pelvic pain and pain from pelvic floor spasm needs to be differentiated and treated specifically. Trigger point massage and injections relieves pain in some patients. Botulinum toxin A, sacral neuromodulation, and acupuncture has been reported in the management of patients with refractory symptoms. Pelvic floor spasm and associated voiding problems are heterogeneous in their pathogenesis and are therefore often underrecognized and undertreated; it is therefore essential that a therapeutic strategy needs to be personalized to the individual patient's requirements. Therefore, careful evaluation and assessment of individuals using a multidisciplinary team approach including a trained physical therapist/nurse clinician is essential in the management of these patients.

  17. Nebular metallicities in two isolated local void dwarf galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Nicholls, David C.; Jerjen, Helmut; Dopita, Michael A. [Research School of Astronomy and Astrophysics, Australian National University, Cotter Rd., Weston ACT 2611 (Australia); Basurah, Hassan, E-mail: David.Nicholls@anu.edu.au [Astronomy Department, King Abdulaziz University, P.O. Box 80203, Jeddah (Saudi Arabia)

    2014-01-01

    Isolated dwarf galaxies, especially those situated in voids, may provide insight into primordial conditions in the universe and the physical processes that govern star formation in undisturbed stellar systems. The metallicity of H II regions in such galaxies is key to investigating this possibility. From the SIGRID sample of isolated dwarf galaxies, we have identified two exceptionally isolated objects, the Local Void galaxy [KK98]246 (ESO 461-G036) and another somewhat larger dwarf irregular on the edge of the Local Void, MCG-01-41-006 (HIPASS J1609-04). We report our measurements of the nebular metallicities in these objects. The first object has a single low luminosity H II region, while the second is in a more vigorous star forming phase with several bright H II regions. We find that the metallicities in both galaxies are typical for galaxies of this size, and do not indicate the presence of any primordial gas, despite (for [KK98]246) the known surrounding large reservoir of neutral hydrogen.

  18. 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)

    1999-12-31

    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)

  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. Multipole analysis of redshift-space distortions around cosmic voids

    International Nuclear Information System (INIS)

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

    2017-01-01

    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 −1 Mpc. 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( z-bar =0.32)=0.599 +0.134 −0.124 and β( z-bar =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 z-bar =0.32, which increases to 3σ when the data is restricted to the lowest available redshift range of 0.15< z <0.33.

  1. 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)

  2. Nebular Metallicities in Two Isolated Local Void Dwarf Galaxies

    Science.gov (United States)

    Nicholls, David C.; Jerjen, Helmut; Dopita, Michael A.; Basurah, Hassan

    2014-01-01

    Isolated dwarf galaxies, especially those situated in voids, may provide insight into primordial conditions in the universe and the physical processes that govern star formation in undisturbed stellar systems. The metallicity of H II regions in such galaxies is key to investigating this possibility. From the SIGRID sample of isolated dwarf galaxies, we have identified two exceptionally isolated objects, the Local Void galaxy [KK98]246 (ESO 461-G036) and another somewhat larger dwarf irregular on the edge of the Local Void, MCG-01-41-006 (HIPASS J1609-04). We report our measurements of the nebular metallicities in these objects. The first object has a single low luminosity H II region, while the second is in a more vigorous star forming phase with several bright H II regions. We find that the metallicities in both galaxies are typical for galaxies of this size, and do not indicate the presence of any primordial gas, despite (for [KK98]246) the known surrounding large reservoir of neutral hydrogen.

  3. Void-free epoxy castings for cryogenic insulators and seals

    International Nuclear Information System (INIS)

    Quirk, J.F.

    1983-01-01

    The design of the Westinghouse Magnet for the Oak Ridge National Laboratory's Large Coil Program (LCP) incorporates a main lead bushing which transmits heat-leak loads by conduction to the supercritical helium stream. The bushing, which consists of epoxy resin cast about a copper conductor, must be electrically insulated, vacuum tight and be capable of withstanding the stresses encountered in cryognic service. The seal design of the bushing is especially important; leakage from either the helium system or the external environment into the vacuum will cause the magnet to quench. Additionally, the epoxy-resin casting must resist mechanical loads caused by the weight of leads attached to the bushing and thermal stresses transmitted to the epoxy via the conductor. The epoxy resin is cast about the conductor in such a way as to provide the required vacuum tight seal. The technique by which this is accomplished is reviewed. Equally important is the elimination of voids in the epoxy which will act as stress-concentrating discontinuities during cooling to or warming from 4K. The types of voids that could be expected and their causes are described. The paper reviews techniques employed to eliminate voids within the cast-resin portion of the bushing

  4. Herpes zoster-associated voiding dysfunction in hematopoietic malignancy patients.

    Science.gov (United States)

    Imafuku, Shinichi; Takahara, Masakazu; Uenotsuchi, Takeshi; Iwato, Koji; Furue, Masutaka

    2008-01-01

    Voiding dysfunction is a rare but important complication of lumbo-sacral herpes zoster. Although the symptoms are transient, the clinical impact on immunocompromised patients cannot be overlooked. To clarify the time course of voiding dysfunction in herpes zoster, 13 herpes zoster patients with voiding dysfunction were retrospectively analyzed. Of 13 patients, 12 had background disease, and six of these were hematopoietic malignancies; four of these patients were hematopoietic stem cell transplant (HSCT) recipients. Ten patients had sacral lesions, two had lumbar, and one had thoracic lesions. Interestingly, patients with severe rash, or with hematopoietic malignancy had later onset of urinary retention than did patients with mild skin symptoms (Mann-Whitney U analysis, P = 0.053) or with other background disease (P = 0.0082). Patients with severe skin rash also had longer durations (P = 0.035). In one case, acute urinary retention occurred as late as 19 days after the onset of skin rash. In immune compromised subjects, attention should be paid to patients with herpes zoster in the lumbo-sacral area for late onset of acute urinary retention even after the resolution of skin symptoms.

  5. The characteristics of void distribution in spalled high purity copper cylinder under sweeping detonation

    Science.gov (United States)

    Yang, Yang; Jiang, Zhi; Chen, Jixinog; Guo, Zhaoliang; Tang, Tiegang; Hu, Haibo

    2018-03-01

    The effects of different peak compression stresses (2-5 GPa) on the spallation behaviour of high purity copper cylinder during sweeping detonation were examined by Electron Backscatter Diffraction Microscopy, Doppler Pins System and Optical Microscopy techniques. The velocity history of inner surface and the characteristics of void distributions in spalled copper cylinder were investigated. The results indicated that the spall strength of copper in these experiments was less than that revealed in previous reports concerning plate impact loading. The geometry of cylindrical copper and the obliquity of incident shock during sweeping detonation may be the main reasons. Different loading stresses seemed to be responsible for the characteristics of the resultant damage fields, and the maximum damage degree increased with increasing shock stress. Spall planes in different cross-sections of sample loaded with the same shock stress of 3.29 GPa were found, and the distance from the initiation end has little effect on the maximum damage degree (the maximum damage range from 12 to 14%), which means that the spallation behaviour was stable along the direction parallel to the detonation propagation direction under the same shock stress.

  6. Radiographic and Histologic Evaluation of a Bone Void that Formed After Recombinant Human Bone Morphogenetic Protein-2-Mediated Sinus Graft Augmentation: A Case Report.

    Science.gov (United States)

    Kang, Hyun-Joo; Jun, Choong-Man; Yun, Jeong-Ho

    2016-01-01

    In the present case report, the authors describe radiographic and histologic observations of a bone void that formed after a sinus augmentation using a graft material that contained recombinant human bone morphogenetic protein-2 (rhBMP-2) and discuss clinical and histologic implications of their findings. Sinus augmentation was performed using a graft material comprising 1 g of hydroxyapatite/β-tricalcium phosphate, which contained 1 mg of rhBMP-2. Radiographic evaluation was conducted with panoramic radiographs and computed tomography images of the augmented maxillary sinus, which were analyzed using a three-dimensional image-reconstruction program. Histologic evaluation was also performed on a biopsy specimen obtained 6 months after the sinus augmentation. The total augmented volume increased from 1,582.2 mm(3) immediately after the sinus augmentation to 3,344.9 mm3 at 6 months after the augmentation because of the formation of a bone void. Twenty-six months after the sinus augmentation, the bone void remained but had reduced in volume, with the total augmented volume reduced to 2,551.7 mm(3). Histologically, new bone was observed to be in contact with the grafted particles, and a fatty marrow-like tissue was present in the area of the bone void. This case report shows that the bone void that had formed after sinus augmentation resolved over time and seemed to be partially replaced with new bone. Furthermore, none of the implants failed, and clinical adverse events were not observed during the follow-up period.

  7. Learning from errors: analysis of medication order voiding in CPOE systems.

    Science.gov (United States)

    Kannampallil, Thomas G; Abraham, Joanna; Solotskaya, Anna; Philip, Sneha G; Lambert, Bruce L; Schiff, Gordon D; Wright, Adam; Galanter, William L

    2017-07-01

    Medication order voiding allows clinicians to indicate that an existing order was placed in error. We explored whether the order voiding function could be used to record and study medication ordering errors. We examined medication orders from an academic medical center for a 6-year period (2006-2011; n  = 5 804 150). We categorized orders based on status (void, not void) and clinician-provided reasons for voiding. We used multivariable logistic regression to investigate the association between order voiding and clinician, patient, and order characteristics. We conducted chart reviews on a random sample of voided orders ( n  = 198) to investigate the rate of medication ordering errors among voided orders, and the accuracy of clinician-provided reasons for voiding. We found that 0.49% of all orders were voided. Order voiding was associated with clinician type (physician, pharmacist, nurse, student, other) and order type (inpatient, prescription, home medications by history). An estimated 70 ± 10% of voided orders were due to medication ordering errors. Clinician-provided reasons for voiding were reasonably predictive of the actual cause of error for duplicate orders (72%), but not for other reasons. Medication safety initiatives require availability of error data to create repositories for learning and training. The voiding function is available in several electronic health record systems, so order voiding could provide a low-effort mechanism for self-reporting of medication ordering errors. Additional clinician training could help increase the quality of such reporting. © The Author 2017. Published by Oxford University Press on behalf of the American Medical Informatics Association. All rights reserved. For Permissions, please email: journals.permissions@oup.com

  8. Is the far border of the Local Void expanding?

    Science.gov (United States)

    Iwata, I.; Chamaraux, P.

    2011-07-01

    Context. According to models of evolution in the hierarchical structure formation scenarios, voids of galaxies are expected to expand. The Local Void (LV) is the closest large void, and it provides a unique opportunity to test observationally such an expansion. It has been found that the Local Group, which is on the border of the LV, is running away from the void center at ~260 km s-1. Aims: In this study we investigate the motion of the galaxies at the far-side border of the LV to examine the presence of a possible expansion. Methods: We selected late-type, edge-on spiral galaxies with radial velocities between 3000 km s-1 and 5000 km s-1, and carried out HI 21 cm line and H-band imaging observations. The near-infrared Tully-Fisher relation was calibrated with a large sample of galaxies and carefully corrected for Malmquist bias. It was used to compute the distances and the peculiar velocities of the LV sample galaxies. Among the 36 sample LV galaxies with good quality HI line width measurements, only 15 galaxies were selected for measuring their distances and peculiar velocities, in order to avoid the effect of Malmquist bias. Results: The average peculiar velocity of these 15 galaxies is found to be -419+208-251 km s-1, which is not significantly different from zero. Conclusions: Due to the intrinsically large scatter of Tully-Fisher relation, we cannot conclude whether there is a systematic motion against the center of the LV for the galaxies at the far-side boundary of the void. However, our result is consistent with the hypothesis that those galaxies at the far-side boundary have an average velocity of ~260 km s-1 equivalent to what is found at the position of the Local Group. Based on data taken at Nançay radiotelescope operated by Observatoire de Paris, CNRS and Université d'Orléans, Infrared Survey Facility (IRSF) which is operated by Nagoya university under the cooperation of South African Astronomical Observatory, Kyoto University, and National

  9. Sensitivity analysis of an impedance void meter to the void distribution in annular flow: A theoretical study

    Energy Technology Data Exchange (ETDEWEB)

    Lemonnier, H.; Nakach, R.; Favreau, C.; Selmer-Olsen, S. (CEA Centre d' Etudes Nucleaires de Grenoble, 38 (France). Service d' Etudes Thermohydrauliques)

    1991-04-01

    Impedance void meters are frequently used to measure the are-averaged void fraction in pipes. This is primarily for two reasons: firstly, this method is non-instrusive since the measurement can be made by electrodes flush mounted in the walls, and secondly, the signal processing equipment is simple. Impedance probes may be calibrated by using a pressure drop measurement or a quick closing valve system. In general, little attention is paid to void distribution effects. It can be proved that in annular flow, the departure from radial symmetry has a strong influence on the measured mean film thickness. This can be easily demonstrated by solving the Laplace equation for the electrical potential by simple analytical methods. When some spatial symmetry conditions are encountered, it is possible to calculate directly the conductance of the two-phase medium without a complete calculation of the potential. A solution of this problem by using the separation of variables technique is also presented. The main difficulty with this technique is the mixed nature of the boundary conditions: the boundary condition is both of Neumann and of Drichlet type on the same coordinate curve. This formulation leads to a non-separable problem, which is solved by truncating an infinite algebraic set of linear equations. The results, although strictly valid in annular flow, may give the correct trends when applied to bubbly flow. Finally, the theory provides an error estimate and a design criterion to improve the probe reliability. (orig.).

  10. Sensitivity analysis of an impedance void meter to the void distribution in annular flow: A theoretical study

    International Nuclear Information System (INIS)

    Lemonnier, H.; Nakach, R.; Favreau, C.; Selmer-Olsen, S.

    1991-01-01

    Impedance void meters are frequently used to measure the are-averaged void fraction in pipes. This is primarily for two reasons: firstly, this method is non-instrusive since the measurement can be made by electrodes flush mounted in the walls, and secondly, the signal processing equipment is simple. Impedance probes may be calibrated by using a pressure drop measurement or a quick closing valve system. In general, little attention is paid to void distribution effects. It can be proved that in annular flow, the departure from radial symmetry has a strong influence on the measured mean film thickness. This can be easily demonstrated by solving the Laplace equation for the electrical potential by simple analytical methods. When some spatial symmetry conditions are encountered, it is possible to calculate directly the conductance of the two-phase medium without a complete calculation of the potential. A solution of this problem by using the separation of variables technique is also presented. The main difficulty with this technique is the mixed nature of the boundary conditions: the boundary condition is both of Neumann and of Drichlet type on the same coordinate curve. This formulation leads to a non-separable problem, which is solved by truncating an infinite algebraic set of linear equations. The results, although strictly valid in annular flow, may give the correct trends when applied to bubbly flow. Finally, the theory provides an error estimate and a design criterion to improve the probe reliability. (orig.)

  11. Direct evidence of void passivation in Cu(InGa)(SSe)2 absorber layers

    International Nuclear Information System (INIS)

    Lee, Dongho; Kim, Young-Su; Mo, Chan B.; Huh, Kwangsoo; Yang, JungYup; Nam, Junggyu; Baek, Dohyun; Park, Sungchan; Kim, ByoungJune; Kim, Dongseop; Lee, Jaehan; Heo, Sung; Park, Jong-Bong; Kang, Yoonmook

    2015-01-01

    We have investigated the charge collection condition around voids in copper indium gallium sulfur selenide (CIGSSe) solar cells fabricated by sputter and a sequential process of selenization/sulfurization. In this study, we found direct evidence of void passivation by using the junction electron beam induced current method, transmission electron microscopy, and energy dispersive X-ray spectroscopy. The high sulfur concentration at the void surface plays an important role in the performance enhancement of the device. The recombination around voids is effectively suppressed by field-assisted void passivation. Hence, the generated carriers are easily collected by the electrodes. Therefore, when the S/(S + Se) ratio at the void surface is over 8% at room temperature, the device performance degradation caused by the recombination at the voids is negligible at the CIGSSe layer

  12. Direct evidence of void passivation in Cu(InGa)(SSe){sub 2} absorber layers

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dongho; Kim, Young-Su; Mo, Chan B.; Huh, Kwangsoo; Yang, JungYup, E-mail: jungyupyang@gmail.com, E-mail: ddang@korea.ac.kr; Nam, Junggyu; Baek, Dohyun; Park, Sungchan; Kim, ByoungJune; Kim, Dongseop [PV Development Team, Energy Solution Business Division, Samsung SDI, 467 Beonyeong-ro, Seobuk-gu, Cheonan-si, Chungcheongnam-do 331-330 (Korea, Republic of); Lee, Jaehan [Core Technology Laboratory, Battery Research Center, Samsung SDI, 130 Samsung-ro, Yeongtong-gu Suwon-si, Gyeonggi-do 443-803 (Korea, Republic of); Heo, Sung; Park, Jong-Bong [Analytical Engineering Group, Samsung Advanced Institute of Technology, 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 443-803 (Korea, Republic of); Kang, Yoonmook, E-mail: jungyupyang@gmail.com, E-mail: ddang@korea.ac.kr [KUKIST Green School, Graduate School of Energy and Environment, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 136-701 (Korea, Republic of)

    2015-02-23

    We have investigated the charge collection condition around voids in copper indium gallium sulfur selenide (CIGSSe) solar cells fabricated by sputter and a sequential process of selenization/sulfurization. In this study, we found direct evidence of void passivation by using the junction electron beam induced current method, transmission electron microscopy, and energy dispersive X-ray spectroscopy. The high sulfur concentration at the void surface plays an important role in the performance enhancement of the device. The recombination around voids is effectively suppressed by field-assisted void passivation. Hence, the generated carriers are easily collected by the electrodes. Therefore, when the S/(S + Se) ratio at the void surface is over 8% at room temperature, the device performance degradation caused by the recombination at the voids is negligible at the CIGSSe layer.

  13. How sudden is a compelling desire to void? An observational cystometric study on the suddenness of this sensation.

    Science.gov (United States)

    De Wachter, Stefan; Wyndaele, Jean-Jacques

    2008-04-01

    To evaluate whether a compelling desire to void (CDV) is always perceived suddenly, or whether it can result from the gradual build-up of bladder-filling sensations. The pattern of filling sensations was evaluated during standard cystometric bladder filling in 75 patients who complained of urgency and showed detrusor overactivity during cystometry. Cystometric filling ended when a CDV was reported. The 'warning volume' is defined as the difference in volume between the first perception of filling and the volume at CDV. Different patterns of bladder-filling sensations were reported. A CDV occurred suddenly, without a preceding sensation in 13% of the patients, whereas 66% reported at least two normal preceding filling sensations before a CDV. The bladder volume at the CDV was significantly smaller in patients that reported no or just one preceding sensation compared with those that reported the normal pattern of two or three sensations (P perception was reported was not different regardless of whether it was described as a first sensation of filling, a first desire or a CDV (P = 0.42). The warning volumes were not different between patients with one or no standardized filling sensations (P = 0.7), but they were significantly smaller than in patients with two or three filling sensations (P = 0.85). A CDV can occur suddenly if normal filling sensation is disturbed, but also gradually if normal filling sensation is preserved. In cases of disturbed filling sensation, the volume at CDV and the warning volume are significantly lower.

  14. Credal Networks under Maximum Entropy

    OpenAIRE

    Lukasiewicz, Thomas

    2013-01-01

    We apply the principle of maximum entropy to select a unique joint probability distribution from the set of all joint probability distributions specified by a credal network. In detail, we start by showing that the unique joint distribution of a Bayesian tree coincides with the maximum entropy model of its conditional distributions. This result, however, does not hold anymore for general Bayesian networks. We thus present a new kind of maximum entropy models, which are computed sequentially. ...

  15. Prediction of void fraction in subcooled flow boiling

    International Nuclear Information System (INIS)

    Petelin, S.; Koncar, B.

    1998-01-01

    The information on heat transfer and especially on the void fraction in the reactor core under subcooled conditions is very important for the water-cooled nuclear reactors, because of its influence upon the reactivity of the systems. This paper gives a short overview of subcooled boiling phenomenon and indicates the simplifications made by the RELAP5 model of subcooled boiling. RELAP5/MOD3.2 calculations were compared with simple one-dimensional models and with high-pressure Bartolomey experiments.(author)

  16. Urethane foam void filling. Innovative technology summary report

    International Nuclear Information System (INIS)

    1998-12-01

    Under the decontamination and decommissioning (D and D) Implementation Plan of the United States Department of Energy's (DOE's) Fernald Environmental Management Project (FEMP), non-recyclable process components and debris that are removed from buildings undergoing D and D are disposed of in an on-site disposal facility (OSDF). Critical to the design and operation of the FEMP's OSDF are provisions to protect against subsidence of the OSDF's cap. Subsidence of the cap could occur if void spaces within the OSDF were to collapse under the overburden of debris and the OSDF cap. Subsidence may create depressions in the OSDF's cap in which rainwater could collect and eventually seep into the OSDF. To minimize voids in the FEMP's OSDF, large metallic components are cut into smaller segments that can be arranged more compactly when placed in the OSDF. Component segmentation using an oxy-acetylene torch was the baseline approach used by the FEMP's D and D contractor on Plant 1, B and W Services, Inc., for the dismantlement and size-reduction of large metal components. Although this technology has performed satisfactorily, it is time-consuming, labor-intensive and costly. Use of the oxy-acetylene torch exposes workers to health and safety hazards including the risk of burns, carbon monoxide, and airborne contamination of residual lead-based paints and other contaminants on the surface of the components being segmented. In addition, solvents used to remove paint from the components before segmenting them emit flammable, noxious fumes. This demonstration investigated the feasibility of placing large vessels intact in the OSDF without segmenting them. To prevent the walls of the vessels from collapsing under the overburden or from degradation, an innovative approach was employed which involved filling the voids in the vessels with a fluid material that hardened on standing. The hardened filling would support the walls of the vessels, and prevent them from collapsing. This report

  17. Method for detecting cement voids or borehole washouts

    International Nuclear Information System (INIS)

    Smith, M.P.

    1980-01-01

    This invention, rather than relying on a measure of the thermal neutron population, uses a measurement of the epithermal neutron population by means of two spaced neutron detectors longitudinally spaced from a neutron source with a relatively high intensity neutron flux. Special detectors discriminate against the detection of thermal neutrons. By comparing the compensated porosity measurement using the dual speed detectors with an uncompensated porosity measured by using only one detector the location of borehole washouts or cement voids can be found. Full details are given. (U.K.)

  18. Method for detecting cement voids or borehole washouts

    International Nuclear Information System (INIS)

    Smith, M.P.

    1978-01-01

    A fast neutron source is used to irradiate earth formations in the vicinity of a well borehole. Dual spaced epithermal neutron detectors are used to sample the epithermal neutron population at two different spaced distances from the source. A compensated formation porosity is obtained from the ratio of counting rates at the dual spaced detectors. An uncompensated porosity value is obtained from the count rate at the short spaced detector. Borehole washout or cement void regions are located by comparing the compensated and uncompensated values of formation porosity obtained in this manner

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-06-02

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

  20. Burnup dependence of coolant void reactivity for ACR-1000 cell

    International Nuclear Information System (INIS)

    Le Tellier, R.; Marleau, G.; Hebert, A.; Roubstov, D.; Altiparmakov, D.; Irish, D.

    2008-01-01

    The Advanced Candu Reactor (ACR-1000) is light water cooled, fueled with enriched uranium and has a smaller lattice pitch than the Candu-6. As a result, the neutronic behavior of the ACR-1000 cell is expected to be somewhat different from that of the Candu-6 leading to a negative coolant void reactivity (CVR). Here we evaluate the CVR for the ACR-1000 cell using the lattice code DRAGON and compare our results with those obtained using the code WIMS-AECL. The differences observed between these two codes for the burnup dependence of the CVR is mainly explained in terms of the specific cell leakage model used by both codes. (authors)

  1. Void fraction calculation in a channel containing boiling coolant

    International Nuclear Information System (INIS)

    Norelli, F.

    1978-01-01

    The problem of void fraction calculation was studied for a channel containing boiling coolant, when a slip ratio correlation is used. Use of fitting (e.g. polinomial or rational algebraic) for slip ratio correlation and the characteristic method are proposed in this work. In this way we are reduced to some elementary quadrature problem. Another problem discussed in the present work concerns what we must consider as ''initial condition'' in any initial value problem, in order to take into account different error distributions in steady state and in successive time-dependent calculations

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

    Science.gov (United States)

    Spolyar, Douglas; Sahlén, Martin; Silk, Joe

    2013-12-13

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

  3. Void fraction measurement system for high temperature flows

    Energy Technology Data Exchange (ETDEWEB)

    Teyssedou, A; Aube, F; Champagne, P [Montreal Univ., PQ (Canada). Institut de Genie Energetique

    1992-05-01

    A {gamma}-ray absorption technique has been developed for measuring the axial distribution of the void fraction for high-temperature and high-pressure two-phase flows. The system is mounted on a moving platform driven by a high-power stepping motor. A personal computer (IBM AT) connected to a data acquisition system is used to control the displacement of the {gamma} source and detector, and to read the response of the detector. All the measurement procedures are carried out automatically by dedicated software developed for this purpose. (Author).

  4. Void fraction and incipient point of boiling during the subcooled nucleate flow boiling of water

    International Nuclear Information System (INIS)

    Unal, H.C.

    1977-01-01

    Void fraction has been determined with high-speed photography for subcooled nucleate flow boiling of water. The data obtained and the data of various investigators for adiabatic flow of stream-water mixtures and saturated bulk boiling of water have yielded a correlation which covers the following conditions: geometry: vertically orientated circular tubes, rectangular channels and annuli; pressure: 2 to 15.9 MN/m 2 ; mass velocity: 388 to 3500 kg/m 2 s; void fraction: 0 to 99%; hydraulic diameter: 0.0047 to 0.0343 m; heat flux: adiabatic and 0.01 to 2.0 MW/m 2 . The accuracy of the correlation is estimated to be 12.5%. The value of the so-called distribution (or flow) parameter has been experimentally determined and found to be equal to 1 for a vertical small-diameter circular tube. The incipient point of boiling for subcooled nucleate flow boiling of water has been determined with high-speed photography. The data obtained and the data available in the literature have yielded a correlation which covers the following conditions: geometry: plate, circular tube and inner tube-heated, outer tube-heated and inner - and outer tube heated annulus; pressure: 0.15 to 15.9 MN/m 2 ; mass velocity: 470 to 17355 kg/m 2 s; hydraulic diameter: 0.00239 to 0.032 m; heat flux: 0.13 to 9.8 MW/m 2 ; subcooling: 2.6 to 108 K; material of heating surface: stainless steel and nickel. The accuracy of the correlation is estimated to be 27.5%. Maximum bubble diameters have been measured at the incipient point of boiling. These data and the data from literature have been correlated for the pressure range of 0.1 to 15.9 MN/m 2 . (author)

  5. EFFECTS OF OXYGEN AND AIR MIXING ON VOID FRACTIONS IN A LARGE SCALE SYSTEM

    International Nuclear Information System (INIS)

    Leishear, R; Hector Guerrero, H; Michael Restivo, M

    2008-01-01

    Oxygen and air mixing with spargers was performed in a 30 foot tall by 30 inch diameter column, to investigate mass transfer as air sparged up through the column and removed saturated oxygen from solution. The mixing techniques required to support this research are the focus of this paper. The fluids tested included water, water with an antifoam agent (AFA), and a high, solids content, Bingham plastic, nuclear waste simulant with AFA, referred to as AZ01 simulant, which is non-radioactive. Mixing of fluids in the column was performed using a recirculation system and an air sparger. The re-circulation system consisted of the column, a re-circulating pump, and associated piping. The air sparger was fabricated from a two inch diameter pipe concentrically installed in the column and open near the bottom of the column. The column contents were slowly re-circulated while fluids were mixed with the air sparger. Samples were rheologically tested to ensure effective mixing, as required. Once the fluids were adequately mixed, oxygen was homogeneously added through the re-circulation loop using a sintered metal oxygen sparger followed by a static mixer. Then the air sparger was re-actuated to remove oxygen from solution as air bubbled up through solution. To monitor mixing effectiveness several variables were monitored, which included flow rates, oxygen concentration, differential pressures along the column height, fluid levels, and void fractions, which are defined as the percent of dissolved gas divided by the total volume of gas and liquid. Research showed that mixing was uniform for water and water with AFA, but mixing for the AZ101 fluid was far more complex. Although mixing of AZ101 was uniform throughout most of the column, gas entrapment and settling of solids significantly affected test results. The detailed test results presented here provide some insight into the complexities of mixing and void fractions for different fluids and how the mixing process itself

  6. EFFECTS OF OXYGEN AND AIR MIXING ON VOID FRACTIONS IN A LARGE SCALE SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Leishear, R; Hector Guerrero, H; Michael Restivo, M

    2008-09-11

    Oxygen and air mixing with spargers was performed in a 30 foot tall by 30 inch diameter column, to investigate mass transfer as air sparged up through the column and removed saturated oxygen from solution. The mixing techniques required to support this research are the focus of this paper. The fluids tested included water, water with an antifoam agent (AFA), and a high, solids content, Bingham plastic, nuclear waste simulant with AFA, referred to as AZ01 simulant, which is non-radioactive. Mixing of fluids in the column was performed using a recirculation system and an air sparger. The re-circulation system consisted of the column, a re-circulating pump, and associated piping. The air sparger was fabricated from a two inch diameter pipe concentrically installed in the column and open near the bottom of the column. The column contents were slowly re-circulated while fluids were mixed with the air sparger. Samples were rheologically tested to ensure effective mixing, as required. Once the fluids were adequately mixed, oxygen was homogeneously added through the re-circulation loop using a sintered metal oxygen sparger followed by a static mixer. Then the air sparger was re-actuated to remove oxygen from solution as air bubbled up through solution. To monitor mixing effectiveness several variables were monitored, which included flow rates, oxygen concentration, differential pressures along the column height, fluid levels, and void fractions, which are defined as the percent of dissolved gas divided by the total volume of gas and liquid. Research showed that mixing was uniform for water and water with AFA, but mixing for the AZ101 fluid was far more complex. Although mixing of AZ101 was uniform throughout most of the column, gas entrapment and settling of solids significantly affected test results. The detailed test results presented here provide some insight into the complexities of mixing and void fractions for different fluids and how the mixing process itself

  7. Last Glacial Maximum Salinity Reconstruction

    Science.gov (United States)

    Homola, K.; Spivack, A. J.

    2016-12-01

    It has been previously demonstrated that salinity can be reconstructed from sediment porewater. The goal of our study is to reconstruct high precision salinity during the Last Glacial Maximum (LGM). Salinity is usually determined at high precision via conductivity, which requires a larger volume of water than can be extracted from a sediment core, or via chloride titration, which yields lower than ideal precision. It has been demonstrated for water column samples that high precision density measurements can be used to determine salinity at the precision of a conductivity measurement using the equation of state of seawater. However, water column seawater has a relatively constant composition, in contrast to porewater, where variations from standard seawater composition occur. These deviations, which affect the equation of state, must be corrected for through precise measurements of each ion's concentration and knowledge of apparent partial molar density in seawater. We have developed a density-based method for determining porewater salinity that requires only 5 mL of sample, achieving density precisions of 10-6 g/mL. We have applied this method to porewater samples extracted from long cores collected along a N-S transect across the western North Atlantic (R/V Knorr cruise KN223). Density was determined to a precision of 2.3x10-6 g/mL, which translates to salinity uncertainty of 0.002 gms/kg if the effect of differences in composition is well constrained. Concentrations of anions (Cl-, and SO4-2) and cations (Na+, Mg+, Ca+2, and K+) were measured. To correct salinities at the precision required to unravel LGM Meridional Overturning Circulation, our ion precisions must be better than 0.1% for SO4-/Cl- and Mg+/Na+, and 0.4% for Ca+/Na+, and K+/Na+. Alkalinity, pH and Dissolved Inorganic Carbon of the porewater were determined to precisions better than 4% when ratioed to Cl-, and used to calculate HCO3-, and CO3-2. Apparent partial molar densities in seawater were

  8. Improved irritative voiding symptoms three years after stereotactic body radiation therapy for prostate cancer.

    Directory of Open Access Journals (Sweden)

    Zakie eRana

    2014-10-01

    Full Text Available Background: Irritative voiding symptoms are common in elderly men and following prostate radiotherapy. The impact of hypofractionated treatment on irritative voiding symptoms has not been determined. This study sought to evaluate urgency, frequency and nocturia following SBRT for prostate cancer. Methods: Patients treated with SBRT monotherapy for localized prostate cancer from August 2007 to July 2011 at Georgetown University Hospital were included in this study. Treatment was delivered using the CyberKnife® with doses of 35 Gy-36.25 Gy in 5 fractions. Patient-reported urinary symptoms were assessed using the International Prostate Symptom Score (IPSS before treatment and at 1, 3, 6, 9, 12 months post-treatment and every 6 months thereafter.Results: 204 patients at a median age of 69 years received SBRT with a median follow-up of 4.8 years. Prior to treatment, 50.0% of patients reported moderate to severe lower urinary track symptoms and 17.7% felt that urinary frequency was a moderate to big problem. The mean prostate volume was 39 cc and 8% had prior procedures for benign prostatic hyperplasia (BPH. A mean baseline IPSS-irritative score of 4.8 significantly increased to 6.5 at 1 month (p 8 at baseline, the mean IPSS-I decreased from a baseline score of 6.8 to 4.9 at three years post-SBRT. This decrease was both statistically (p < 0.0001 and clinically significant (MID = 1.45. Only 14.6% of patients felt that urinary frequency was a moderate to big problem at three years post-SBRT (p = 0.23.Conclusions: Treatment of prostate cancer

  9. Closure behavior of spherical void in slab during hot rolling process

    Science.gov (United States)

    Cheng, Rong; Zhang, Jiongming; Wang, Bo

    2018-04-01

    The mechanical properties of steels are heavily deteriorated by voids. The influence of voids on the product quality should be eliminated through rolling processes. The study on the void closure during hot rolling processes is necessary. In present work, the closure behavior of voids at the center of a slab at 800 °C during hot rolling processes has been simulated with a 3D finite element model. The shape of the void and the plastic strain distribution of the slab are obtained by this model. The void decreases along the slab thickness direction and spreads along the rolling direction but hardly changes along the strip width direction. The relationship between closure behavior of voids and the plastic strain at the center of the slab is analyzed. The effects of rolling reduction, slab thickness and roller diameter on the closure behavior of voids are discussed. The larger reduction, thinner slab and larger roller diameter all improve the closure of voids during hot rolling processes. Experimental results of the closure behavior of a void in the slab during hot rolling process mostly agree with the simulation results..

  10. Hyperuniformity, quasi-long-range correlations, and void-space constraints in maximally random jammed particle packings. I. Polydisperse spheres.

    Science.gov (United States)

    Zachary, Chase E; Jiao, Yang; Torquato, Salvatore

    2011-05-01

    Hyperuniform many-particle distributions possess a local number variance that grows more slowly than the volume of an observation window, implying that the local density is effectively homogeneous beyond a few characteristic length scales. Previous work on maximally random strictly jammed sphere packings in three dimensions has shown that these systems are hyperuniform and possess unusual quasi-long-range pair correlations decaying as r(-4), resulting in anomalous logarithmic growth in the number variance. However, recent work on maximally random jammed sphere packings with a size distribution has suggested that such quasi-long-range correlations and hyperuniformity are not universal among jammed hard-particle systems. In this paper, we show that such systems are indeed hyperuniform with signature quasi-long-range correlations by characterizing the more general local-volume-fraction fluctuations. We argue that the regularity of the void space induced by the constraints of saturation and strict jamming overcomes the local inhomogeneity of the disk centers to induce hyperuniformity in the medium with a linear small-wave-number nonanalytic behavior in the spectral density, resulting in quasi-long-range spatial correlations scaling with r(-(d+1)) in d Euclidean space dimensions. A numerical and analytical analysis of the pore-size distribution for a binary maximally random jammed system in addition to a local characterization of the n-particle loops governing the void space surrounding the inclusions is presented in support of our argument. This paper is the first part of a series of two papers considering the relationships among hyperuniformity, jamming, and regularity of the void space in hard-particle packings.

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

    International Nuclear Information System (INIS)

    Persson, Rolf

    1966-09-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Persson, Rolf

    1966-09-15

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

  13. Monitoring Detrusor Oxygenation and Hemodynamics Noninvasively during Dysfunctional Voiding

    Science.gov (United States)

    Macnab, Andrew J.; Stothers, Lynn S.; Shadgan, Babak

    2012-01-01

    The current literature indicates that lower urinary tract symptoms (LUTSs) related to benign prostatic hyperplasia (BPH) have a heterogeneous pathophysiology. Pressure flow studies (UDSs) remain the gold standard evaluation methodology for such patients. However, as the function of the detrusor muscle depends on its vasculature and perfusion, the underlying causes of LUTS likely include abnormalities of detrusor oxygenation and hemodynamics, and available treatment options include agents thought to act on the detrusor smooth muscle and/or vasculature. Hence, near infrared spectroscopy (NIRS), an established optical methodology for monitoring changes in tissue oxygenation and hemodynamics, has relevance as a means of expanding knowledge related to the pathophysiology of BPH and potential treatment options. This methodological report describes how to conduct simultaneous NIRS monitoring of detrusor oxygenation and hemodynamics during UDS, outlines the clinical implications and practical applications of NIRS, explains the principles of physiologic interpretation of NIRS voiding data, and proposes an exploratory hypothesis that the pathophysiological causes underlying LUTS include detrusor dysfunction due to an abnormal hemodynamic response or the onset of oxygen debt during voiding. PMID:23019422

  14. Monitoring Detrusor Oxygenation and Hemodynamics Noninvasively during Dysfunctional Voiding

    Directory of Open Access Journals (Sweden)

    Andrew J. Macnab

    2012-01-01

    Full Text Available The current literature indicates that lower urinary tract symptoms (LUTSs related to benign prostatic hyperplasia (BPH have a heterogeneous pathophysiology. Pressure flow studies (UDSs remain the gold standard evaluation methodology for such patients. However, as the function of the detrusor muscle depends on its vasculature and perfusion, the underlying causes of LUTS likely include abnormalities of detrusor oxygenation and hemodynamics, and available treatment options include agents thought to act on the detrusor smooth muscle and/or vasculature. Hence, near infrared spectroscopy (NIRS, an established optical methodology for monitoring changes in tissue oxygenation and hemodynamics, has relevance as a means of expanding knowledge related to the pathophysiology of BPH and potential treatment options. This methodological report describes how to conduct simultaneous NIRS monitoring of detrusor oxygenation and hemodynamics during UDS, outlines the clinical implications and practical applications of NIRS, explains the principles of physiologic interpretation of NIRS voiding data, and proposes an exploratory hypothesis that the pathophysiological causes underlying LUTS include detrusor dysfunction due to an abnormal hemodynamic response or the onset of oxygen debt during voiding.

  15. The urodynamic evaluation of neuromodulation in patients with voiding dysfunction.

    Science.gov (United States)

    Everaert, K; Plancke, H; Lefevere, F; Oosterlinck, W

    1997-05-01

    To determine which patients with voiding dysfunction might be suitable for treatment with neuromodulation, using urodynamics to obtain an objective measure of improvement and to illustrate the effect of neuromodulation on voiding dysfunction. Patients were selected for implantation of a neuroprosthesis using a urodynamic evaluation before and during subchronic stimulation; 27 such patients (four men and 23 women, mean age 33 years, SD 15) were evaluated. Of the 27 patients, the 17 who responded well to neuromodulation all had hypocontractile detrusors and sphincter hypertonicity; sphincter relaxation during micturition was impaired. The urodynamic evaluation showed that these patients were not obstructed. Of 10 patients with spastic pelvic floor syndrome, nine responded well to the treatment. Those not responding to neuromodulation had mainly acontractile detrusors. The ideal candidates for neuromodulation are those patients with a spastic pelvic floor syndrome or with a hypocontractile detrusor, in combination with sphincter instability, and impaired sphincter relaxation. An increase of bladder contractility, enhancement of sphincter relaxation and decrease in bladder capacity and residual urine are the most important features of the response.

  16. Are we living near the center of a local void?

    Energy Technology Data Exchange (ETDEWEB)

    Cusin, Giulia [Département de Physique Théorique and Center for Astroparticle Physics, Université de Genève, 24 quai Ansermet, CH-1211 Genève 4 (Switzerland); Pitrou, Cyril; Uzan, Jean-Philippe, E-mail: giulia.cusin@unige.ch, E-mail: pitrou@iap.fr, E-mail: uzan@iap.fr [Institut d' Astrophysique de Paris, Université Pierre and Marie Curie—Paris V, CNRS-UMR 7095, 98 bis, Bd Arago, 75014 Paris (France)

    2017-03-01

    The properties of the cosmic microwave background (CMB) temperature and polarisation anisotropies measured by a static, off-centered observer located in a local spherically symmetric void, are described. In particular in this paper we compute, together with the standard 2-point angular correlation functions, the off-diagonal correlators, which are no more vanishing by symmetry. While the energy shift induced by the off-centered position of the observer can be suppressed by a proper choice of the observer velocity, a lensing-like effect on the CMB emission point remains. This latter effect is genuinely geometrical (e.g. non-degenerate with a boost) and reflects in the structure of the off-diagonal correlators. At lowest order in this effect, the temperature and polarisation correlation matrices have non-vanishing diagonal elements, as usual, and all the off-diagonal terms are excited. This particular signature of a local void model allows one, in principle, to disentangle geometrical effects from local kinematical ones in CMB observations.

  17. The use of graphite for the reduction of void reactivity in CANDU reactors

    International Nuclear Information System (INIS)

    Min, B.J.; Kim, B.G.; Sim, K-S.

    1995-01-01

    Coolant void reactivity can be reduced by using burnable poison in CANDU reactors. The use of graphite in the fuel bundle is introduced to reduce coolant void reactivity by adding an appropriate amount of burnable poison in the central rod. This study shows that sufficiently low void reactivity which in controllable by Reactor Regulating System (RRS) can be achieved by using graphite used fuel with slightly enriched uranium. Zero void reactivity can be also obtained by using graphite used fuel with a large central rod. A new fuel bundle with graphite rods can substantially reduce the void reactivity with less burnup penalty compared to previously proposed low void reactivity fuel with depleted uranium. (author)

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

    International Nuclear Information System (INIS)

    Pushkareva, Marina; Adrien, Jérôme; Maire, Eric; Segurado, Javier; Llorca, Javier; Weck, Arnaud

    2016-01-01

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

  19. The metallurgical approach on the solder voids behaviour in surface mount devices

    International Nuclear Information System (INIS)

    Mohabattul Zaman Bukhari

    1996-01-01

    Solder voids are believed to cause poor heat dissiption in the Surface Mount devices and reduce the reliability of the devices at higher operating services. There are a lot of factors involved in creating voids such as gas/flux entrapment, wettability, outgasseous, air bubbles in the solder paste, inconsistency of solder coverage and improper metal scheme selection. This study was done to observe the behaviour of the solder voids in term of flux entrapmentt and wettability. It is believed that flux entrapment and wettability are verify this hypothesis. Two types of metal scheme were chosen which are Nickel (Ni) plated and Tin (Sn) plated heatsink. X-ray techniques such as Radiographic Inspection Analysis and EDAX were used to detect the minute solder voids. The solder voids observed on the heatsinks and Copper shims after the reflow process are believed to be a non contact voids that resulted from some portion of the surface not wetting properly

  20. Method of simulating spherical voids for use as a radiographic standard

    International Nuclear Information System (INIS)

    Foster, B.E.

    1977-01-01

    A method of simulating small spherical voids in metal is provided. The method entails drilling or etching a hemispherical depression of the desired diameter in each of two sections of metal, the sections being flat plates or different diameter cylinders. A carbon bead is placed in one of the hemispherical voids and is used as a guide to align the second hemispherical void with that in the other plate. The plates are then bonded together with epoxy, tape or similar material and the two aligned hemispheres form a sphere within the material; thus a void of a known size has been created. This type of void can be used to simulate a pore in the development of radiographic techniques of actual voids (porosity) in welds and serve as a radiographic standard

  1. Measurements of void fraction in a heated tube in the rewetting conditions

    International Nuclear Information System (INIS)

    Freitas, R.L.

    1983-01-01

    The methods of void fraction measurements by transmission and diffusion of cold, thermal and epithermal neutrons were studied with cylindrical alluminium pieces simulating the steam. A great set of void fraction found in a wet zone was examined and a particulsar attention was given to the sensitivity effects of the method, mainly for high void fraction. Several aspects of the measurement techniques were analyzed, such as the effect of the phase radial distribution, neutron energy, water tempeture, effect of the void axial gradient. The technique of thermal neutron diffusion measurement was used to measure the axial profile of void fraction in a steady two-phase flow, where the pressure, mass velocity and heat flux are representative of the wet conditions. Experimental results are presented and compared with different void fraction models. (E.G.) [pt

  2. Shock-induced hotspot formation and chemical reaction initiation in PETN containing a spherical void

    International Nuclear Information System (INIS)

    Shan, Tzu-Ray; Thompson, Aidan P

    2014-01-01

    We present results of reactive molecular dynamics simulations of hotspot formation and chemical reaction initiation in shock-induced compression of pentaerythritol tetranitrate (PETN) with the ReaxFF reactive force field. A supported shockwave is driven through a PETN crystal containing a 20 nm spherical void at a sub-threshold impact velocity of 2 km/s. Formation of a hotspot due to shock-induced void collapse is observed. During void collapse, NO 2 is the dominant species ejected from the upstream void surface. Once the ejecta collide with the downstream void surface and the hotspot develops, formation of final products such as N 2 and H 2 O is observed. The simulation provides a detailed picture of how void collapse and hotspot formation leads to initiation at sub-threshold impact velocities.

  3. Structure-dependent behavior of stress-induced voiding in Cu interconnects

    International Nuclear Information System (INIS)

    Wu Zhenyu; Yang Yintang; Chai Changchun; Li Yuejin; Wang Jiayou; Li Bin; Liu Jing

    2010-01-01

    Stress modeling and cross-section failure analysis by focused-ion-beam have been used to investigate stress-induced voiding phenomena in Cu interconnects. The voiding mechanism and the effect of the interconnect structure on the stress migration have been studied. The results show that the most concentrated tensile stress appears and voids form at corners of vias on top surfaces of Cu M1 lines. A simple model of stress induced voiding in which vacancies arise due to the increase of the chemical potential under tensile stress and diffuse under the force of stress gradient along the main diffusing path indicates that stress gradient rather than stress itself determines the voiding rate. Cu interconnects with larger vias show less resistance to stress-induced voiding due to larger stress gradient at corners of vias.

  4. 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

    by mechanical deformation. The aim of this paper is to analyze numerically if and to what degree the voids areclosed by the forging. Using the commercial simulation software ABAQUS, both simplified model ingots and physically manufactured ingots containing prescribed void distributions are deformed and analyzed....... The analysis concernsboth the void density change and the location of the voids in the part after deformation. The latter can be important for the subsequent reliability of the parts, for instance regarding fatigue properties. The analysis incorporates the Gurson yield criterion for metals containing voids...... and focuses on how the voids deform depending on their size and distribution in the ingot as well ashow the forging forces are applied....

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-08-01

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

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

    International Nuclear Information System (INIS)

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

    2016-01-01

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

  7. Stocking and structure for maximum growth in sugar maple selection stands.

    Science.gov (United States)

    Thomas R. Crow; Carl H. Tubbs; Rodney D. Jacobs; Robert R. Oberg

    1981-01-01

    The impacts of stocking, structure, and cutting cycle on basal area, cubic foot volume, board foot volume, and diameter growth are considered. Recommendations are provided for maximum growth in uneven-aged sugar maple stands.

  8. The effect of voids on the hardening of body-centered cubic Fe

    Energy Technology Data Exchange (ETDEWEB)

    Nakai, Ryosuke, E-mail: ryosuke.nakai@jupiter.qse.tohoku.ac.jp [Department of Quantum Science and Energy Engineering, Tohoku University, 6-6-01-2, Aramaki-Aza-Aoba, Aobaku, Sendai, Miyagi, 980-8579 (Japan); Yabuuchi, Kiyohiro, E-mail: k-yabuuchi@iae.kyoto-u.ac.jp [Department of Quantum Science and Energy Engineering, Tohoku University, 6-6-01-2, Aramaki-Aza-Aoba, Aobaku, Sendai, Miyagi, 980-8579 (Japan); Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto, 611-0011 (Japan); Nogami, Shuhei, E-mail: shuhei.nogami@qse.tohoku.ac.jp [Department of Quantum Science and Energy Engineering, Tohoku University, 6-6-01-2, Aramaki-Aza-Aoba, Aobaku, Sendai, Miyagi, 980-8579 (Japan); Hasegawa, Akira, E-mail: akira.hasegawa@qse.tohoku.ac.jp [Department of Quantum Science and Energy Engineering, Tohoku University, 6-6-01-2, Aramaki-Aza-Aoba, Aobaku, Sendai, Miyagi, 980-8579 (Japan)

    2016-04-01

    The mechanical properties of metals are affected by various types of defects. Hardening is usually described through the interaction between dislocations and obstacles, in the so-called line tension theory. The strength factor in the line tension theory represents the resistance of a defect against the dislocation motion. In order to understand hardening from the viewpoint of the microstructure, an accurate determination of the strength factor of different types of defects is essential. In the present study, the strength factor of voids in body-centered cubic (BCC) Fe was investigated by two different approaches: one based on the Orowan equation to link the measured hardness with the average size and density of voids, and the other involving direct observation of the interaction between dislocations and voids by transmission electron microscope (TEM). The strength factor of voids induced by ion irradiation estimated by the Orowan equation was 0.6, whereas the strength factor estimated by the direct TEM approach was 0.8. The difference in the strength factors measured by the two approaches is due to the positional relationship between dislocations and voids: the central region of a void is stronger than the tip. Moreover, the gliding plane and the direction of dislocation may also affect the strength factor of voids. This study determined the strength factor of voids in BCC Fe accurately, and suggested that the contribution of voids to the irradiation hardening is larger than that of dislocation loops and Cu-rich precipitates. - Highlights: • The strength factor of voids in BCC Fe was experimentally investigated. • The strength factor of voids estimated by the line tension theory was 0.6. • The strength factor of voids estimated by the bowing angle of dislocations was 0.8. • The different strength factors are due to the positional relationship.

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

    Science.gov (United States)

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

    2013-01-01

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

  10. Dependence of calculated void reactivity on film boiling representation in a CANDU lattice

    Energy Technology Data Exchange (ETDEWEB)

    Whitlock, J [McMaster Univ., Hamilton, ON (Canada). Dept. of Engineering Physics

    1994-12-31

    The distribution dependence of void reactivity in a CANDU (CANada Deuterium Uranium) lattice is studied, specifically in the regime of film boiling. A heterogeneous model of this phenomenon predicts a 4% increase in void reactivity over a homogeneous model for fresh fuel, and 11% at discharge. An explanation for this difference is offered, with regard to differing changes in neutron mean free path upon voiding. (author). 9 refs., 4 tabs., 6 figs.

  11. Molecular dynamics modeling and simulation of void growth in two dimensions

    Science.gov (United States)

    Chang, H.-J.; Segurado, J.; Rodríguez de la Fuente, O.; Pabón, B. M.; LLorca, J.

    2013-10-01

    The mechanisms of growth of a circular void by plastic deformation were studied by means of molecular dynamics in two dimensions (2D). While previous molecular dynamics (MD) simulations in three dimensions (3D) have been limited to small voids (up to ≈10 nm in radius), this strategy allows us to study the behavior of voids of up to 100 nm in radius. MD simulations showed that plastic deformation was triggered by the nucleation of dislocations at the atomic steps of the void surface in the whole range of void sizes studied. The yield stress, defined as stress necessary to nucleate stable dislocations, decreased with temperature, but the void growth rate was not very sensitive to this parameter. Simulations under uniaxial tension, uniaxial deformation and biaxial deformation showed that the void growth rate increased very rapidly with multiaxiality but it did not depend on the initial void radius. These results were compared with previous 3D MD and 2D dislocation dynamics simulations to establish a map of mechanisms and size effects for plastic void growth in crystalline solids.

  12. Molecular dynamics modeling and simulation of void growth in two dimensions

    International Nuclear Information System (INIS)

    Chang, H-J; Segurado, J; LLorca, J; Rodríguez de la Fuente, O; Pabón, B M

    2013-01-01

    The mechanisms of growth of a circular void by plastic deformation were studied by means of molecular dynamics in two dimensions (2D). While previous molecular dynamics (MD) simulations in three dimensions (3D) have been limited to small voids (up to ≈10 nm in radius), this strategy allows us to study the behavior of voids of up to 100 nm in radius. MD simulations showed that plastic deformation was triggered by the nucleation of dislocations at the atomic steps of the void surface in the whole range of void sizes studied. The yield stress, defined as stress necessary to nucleate stable dislocations, decreased with temperature, but the void growth rate was not very sensitive to this parameter. Simulations under uniaxial tension, uniaxial deformation and biaxial deformation showed that the void growth rate increased very rapidly with multiaxiality but it did not depend on the initial void radius. These results were compared with previous 3D MD and 2D dislocation dynamics simulations to establish a map of mechanisms and size effects for plastic void growth in crystalline solids. (paper)

  13. Characteristics of dust voids in a strongly coupled laboratory dusty plasma

    Science.gov (United States)

    Bailung, Yoshiko; Deka, T.; Boruah, A.; Sharma, S. K.; Pal, A. R.; Chutia, Joyanti; Bailung, H.

    2018-05-01

    A void is produced in a strongly coupled dusty plasma by inserting a cylindrical pin (˜0.1 mm diameter) into a radiofrequency discharge argon plasma. The pin is biased externally below the plasma potential to generate the dust void. The Debye sheath model is used to obtain the sheath potential profile and hence to estimate the electric field around the pin. The electric field force and the ion drag force on the dust particles are estimated and their balance accounts well for the maintenance of the size of the void. The effects of neutral density as well as dust density on the void size are studied.

  14. An experimental and theoretical analysis of void fraction dynamics in a boiling channel

    International Nuclear Information System (INIS)

    Romberg, T.M.

    1977-01-01

    This paper describes an experimental and theoretical investigation of the void fraction dynamics at the exit of a test boiling channel which is operated near the 'instability threshold power' (the power level at which coolant flow instabilities occur). Dynamic measurements of the perturbations in channel inlet flow-rate, power input and exit void fraction are analysed using multivariate spectral analysis. The resulting experimental cross-spectral density functions between flow-rate/exit void fraction and power input/exit void fraction agree favourably with those calculated by a linearised hydrodynamic model in the frequency domain. (Author)

  15. Atomistic simulations of void migration under thermal gradient in UO2

    International Nuclear Information System (INIS)

    Desai, Tapan G.; Millett, Paul; Tonks, Michael; Wolf, Dieter

    2010-01-01

    It is well known that within a few hours after startup of a nuclear reactor, the temperature gradient within a fuel element causes migration of voids/bubbles radially inwards to form a central hole. To understand the atomic processes that control this migration of voids, we performed molecular dynamics (MD) simulations on single crystal UO 2 with voids of diameter 2.2 nm. An external temperature gradient was applied across the simulation cell. At the end of the simulation run, it was observed that the voids had moved towards the hot end of the simulation cell. The void migration velocity obtained from the simulations was compared with the available phenomenological equations for void migration due to different transport mechanisms. Surface diffusion of the slowest moving specie, i.e. uranium, was found to be the dominant mechanism for void migration. The contribution from lattice diffusion and the thermal stress gradient to the void migration was analyzed and found to be negligible. By extrapolation, a crossover from the surface-diffusion-controlled mechanism to the lattice-diffusion-controlled mechanism was found to occur for voids with sizes in the μm range.

  16. Irradiation-induced void evolution in iron: A phase-field approach with atomistic derived parameters

    International Nuclear Information System (INIS)

    Wang Yuan-Yuan; Ding Jian-Hua; Huang Shao-Song; Zhao Ji-Jun; Liu Wen-Bo; Ke Xiao-Qin; Wang Yun-Zhi; Zhang Chi

    2017-01-01

    A series of material parameters are derived from atomistic simulations and implemented into a phase field (PF) model to simulate void evolution in body-centered cubic (bcc) iron subjected to different irradiation doses at different temperatures. The simulation results show good agreement with experimental observations — the porosity as a function of temperature varies in a bell-shaped manner and the void density monotonically decreases with increasing temperatures; both porosity and void density increase with increasing irradiation dose at the same temperature. Analysis reveals that the evolution of void number and size is determined by the interplay among the production, diffusion and recombination of vacancy and interstitial. (paper)

  17. Experimental study of average void fraction in low-flow subcooled boiling

    International Nuclear Information System (INIS)

    Sun Qi; Wang Xiaojun; Xi Zhao; Zhao Hua; Yang Ruichang

    2005-01-01

    Low-flow subcooled void fraction in medium pressure was investigated using high-temperature high-pressure single-sensor optical probe in this paper. And then average void fraction was obtained through the integral calculation of local void fraction in the cross-section. The experimental data were compared with the void fraction model proposed in advance. The results show that the predictions of this model agree with the data quite well. The comparisons of Saha and Levy models with low-flow subcooled data show that Saha model overestimates the experimental data distinctively, and Levy model also gets relatively higher predictions although it is better than Saha model. (author)

  18. Void Fraction Measurement in Subcooled-Boiling Flow Using High-Frame-Rate Neutron Radiography

    International Nuclear Information System (INIS)

    Kureta, Masatoshi; Akimoto, Hajime; Hibiki, Takashi; Mishima, Kaichiro

    2001-01-01

    A high-frame-rate neutron radiography (NR) technique was applied to measure the void fraction distribution in forced-convective subcooled-boiling flow. The focus was experimental technique and error estimation of the high-frame-rate NR. The results of void fraction measurement in the boiling flow were described. Measurement errors on instantaneous and time-averaged void fractions were evaluated experimentally and analytically. Measurement errors were within 18 and 2% for instantaneous void fraction (measurement time is 0.89 ms), and time-averaged void fraction, respectively. The void fraction distribution of subcooled boiling was measured using atmospheric-pressure water in rectangular channels with channel width 30 mm, heated length 100 mm, channel gap 3 and 5 mm, inlet water subcooling from 10 to 30 K, and mass velocity ranging from 240 to 2000 kg/(m 2 .s). One side of the channel was heated homogeneously. Instantaneous void fraction and time-averaged void fraction distribution were measured parametrically. The effects of flow parameters on void fraction were investigated

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

    DEFF Research Database (Denmark)

    McAllister, Iain Wilson

    1993-01-01

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

  20. Mechanistic model for void distribution in flashing flow

    International Nuclear Information System (INIS)

    Riznic, J.; Ishii, M.; Afgan, N.

    1987-01-01

    A problem of discharging of an initially subcooled liquid from a high pressure condition into a low pressure environment is quite important in several industrial systems such as nuclear reactors and chemical reactors. A new model for the flashing process is proposed here based on the wall nucleation theory, bubble growth model and drift-flux bubble transport model. In order to calculate the bubble number density, the bubble number transport equation with a distributed source from the wall nucleation sites is used. The model predictions in terms of the void fraction are compared to Moby Dick and BNL experimental data. It shows that satisfactory agreements could be obtained from the present model without any floating parameter to be adjusted with data. This result indicates that, at least for the experimental conditions considered here, the mechanistic prediction of the flashing phenomenon is possible based on the present wall nucleation based model. 43 refs., 4 figs

  1. Water tests for determining post voiding behavior in the LMFBR

    International Nuclear Information System (INIS)

    Hinkle, W.D.

    1976-06-01

    The most serious of the postulated accidents considered in the design of the Liquid Metal Cooled Fast Breeder Reactor (LMFBR) is the Loss of Pipe Integrity (LOPI) accident. Analysis models used to calculate the consequences of this accident assume that once boiling is initiated film dryout occurs in the hot assembly as a result of rapid vapor bubble growth and consequent flow stoppage or reversal. However, this assumption has not been put to any real test. Once boiling is initiated in the hot assembly during an LMFBR LOPI accident, a substantial gravity pressure difference would exist between this assembly and other colder assemblies in the core. This condition would give rise to natural circulation flow boiling accompanied by pressure and flow oscillations. It is possible that such oscillations could prevent or delay dryout and provide substantial post-voiding heat removal. The tests described were conceived with the objective of obtaining basic information and data relating to this possibility

  2. Measurement of local void fraction at elevated temperature and pressure

    International Nuclear Information System (INIS)

    Duncan, D.; Trabold, T.A.

    1993-03-01

    Significant advances have recently been made in analytical and computational methods for the prediction of local thermal-hydraulic conditions in gas/liquid two-phase flows. There is, however, a need for extensive experimental data, for the dual purposes of constitutive relation development and code qualification. There is especially true of systems involving complicated geometries and/or extreme flow conditions for which little, if any, applicable information exists in the open literature. For the tests described in the present paper, a novel electrical probe has been applied to measure the void fraction in atmospheric pressure air/water flows, and steam/water mixtures at high temperature and pressure. The data acquired in the latter experiments are compared with the results of a one-dimensional two-fluid computational analysis

  3. Partial discharge characteristics and mechanism in voids at impulse voltages

    International Nuclear Information System (INIS)

    Zhao, X F; Guo, Z F; Wang, Y Y; Li, J H; Li, Y M; Yao, X

    2011-01-01

    Partial discharge (PD) characteristics and mechanism in artificial cavities in an epoxy plate have been investigated for different void dimensions and impulse voltage waveforms. A differential measurement system was developed in order to detect PD current pulses effectively. Experimental results showed that the 50% probability PD inception voltage (PDIV 50 ) increases initially as the cavity diameter decreases at constant depth for double exponential impulses as well as oscillating impulses, but after aging, it becomes independent of the cavity diameter. Moreover, some distinctive characteristics of PD (e.g. main discharge and reverse discharge during the rise and fall phases of the applied voltage) were also investigated. The differences of the PD propagation and the mechanism between double exponential impulses and oscillating impulse were discussed

  4. Is voiding cystourethrogram necessary in all cases of antenatal hydronephrosis?

    Directory of Open Access Journals (Sweden)

    M S Ansari

    2009-01-01

    Full Text Available Hydronephrosis is the most common genitourinary anomaly as detected on obstetric ultrasonography and the incidence of associated vesicoureteral reflux is around 10-12%. There is inconsistency in the literature regarding which child should under go a voiding cystourethrogram (VCUG in cases of antenatal hydronephrosis (AHN. Besides, there is a scarcity of prospective studies to demonstrate the risk of varying degree of AHN, associated reflux and their long-term impact on the kidneys. The present analysis suggests that children with AHN should undergo an ultrasound within the first month of life and further course of action should be decided on the basis of the individual case. Children with persistent moderate to severe AHN should undergo a VCUG and a functional study.

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

    Directory of Open Access Journals (Sweden)

    Cahill R. T.

    2011-04-01

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

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

    Directory of Open Access Journals (Sweden)

    Cahill R. T.

    2011-04-01

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

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

    International Nuclear Information System (INIS)

    Del Nevo, A.; Michelotti, L.; Moretti, F.; Rozzia, D.; D'Auria, F.

    2011-01-01

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

  8. Detection of coolant void in lead-cooled fast reactors

    International Nuclear Information System (INIS)

    Wolniewicz, Peter; Håkansson, Ane; Jansson, Peter

    2015-01-01

    Highlights: • We model the ALFRED LFR using different Monte-Carlo codes. • We study the impact on coolant void on the fission cross section in fission chambers. • We develop a methodology to detect coolant void. • We study the impact of detector fissile coating burn-up. • We conclude that the developed methodology may be an attractive complement to LFR monitoring. - Abstract: Previous work (Wolniewicz et al., 2013) has indicated that using fission chambers coated with 242 Pu and 235 U, respectively, can provide the means of detecting changes in the neutron flux that are connected to coolant density changes in a small lead-cooled fast reactor. Such density changes may be due to leakages of gas into the coolant, which, over time, may coalesce to large bubbles implying a high risk of causing severe damage of the core. By using the ratio of the information provided by the two types of detectors a quantity is obtained that is sensitive to these density changes and, to the first order approximation, independent of the power level of the reactor. In this work we continue the investigation of this proposed methodology by applying it to the Advanced LFR European Demonstrator (ALFRED) and using realistic modelling of the neutron detectors. The results show that the methodology may be used to detect density changes indicating the initial stages of a coalescence process that may result in a large bubble. Also, it is shown that under certain circumstances, large bubbles passing through the core could be detected with this methodology

  9. Coolant voiding analysis following SGTR for an HLMC reactor

    International Nuclear Information System (INIS)

    Farmer, M.T.; Spencer, B.W.; Sienicki, J.J.

    2000-01-01

    Concepts are under development at Argonne National Laboratory for a small, modular, proliferation-resistant nuclear power steam supply system. Of primary interest here is the simplified system design, featuring steam generators that are directly immersed in the lead-bismuth eutectic (LBE) coolant of the primary system. To support the safety case for this design approach, model development and analysis of transient coolant voiding during a postulated guillotine-type steam generator tube rupture event has been carried out. For the current design, the blowdown will occur from the steam generator shell into the ruptured 12.7-mm-inside-diameter tube through which the LBE coolant passes. The steam will expand biaxially in the tube, with a portion of the flow vented upward to eventually expand into the cover-gas region, while the balance of the flow is vented downward as a jet into the surrounding downward-flowing LBE. Coolant freezing is not an issue in this case because of high feedwater temperature in relation to the freezing point of the LBE. The specific objectives of the current work are to (a) determine the penetration behavior of the steam jet into the lower cold-leg region, (b) characterize the resultant void behavior in terms of coherent bubble versus breakup into a size distribution of small bubbles, and (c) characterize the motion of the bubbles with regard to rise to the cover-gas region (via the liner-to-coolant vessel gap) versus downward transport with the flowing LBE and subsequent upflow through the core to the cover-gas region

  10. Determining the concentration of individual eruptive events of the CAMP: Distinguishing interflow hiatuses from subterranean alteration and void infilling.

    Science.gov (United States)

    Olsen, P. E.; Kent, D. V.; Et-Touhami, M.

    2012-04-01

    More important than the total volume of eruptives in a LIP is the concentration in time of individual eruptions with timescales relevant for environmental change. In CAMP lavas, interflow sedimentary and reddened levels are interpreted as evidence of significant time between flows of hundreds to thousands of years allowing soil development and sediment deposition. Additionally, cross-cutting or enclosed sediment bodies, and basalt and sediment mixtures are interpreted as clastic intrusions and phreatic mixing (peperites). Here we show that most such occurrences are more consistent with post-emplacement alteration and void infill by sediment. Criteria for recognizing void fillings in cross-cutting, enclosed or mixed basalt include: 1) paleo-horizontal sediment stratification independent of basalt clasts or void walls - i.e., geopedal; 2) presence of clasts alien to underlying units such as lithic clasts or bones, the latter analogous to karst occurrences; 3) presence of current structures such as ripples; 4) lack of basalt chill margins; and 5) preserved stratigraphy related to overlying units. Criteria for recognizing flow-contact-parallel sediment bodies and reddened and altered contacts as post-emplacement alteration and void infill include: 1) reddening and alteration of both the upper surface of the older flow AND the lower surface of the overlying flow (caused by post-emplacement ground-water-flow); 2) presence of clasts derived from the bottom of the overlying flow; 3) location of tabular sediment bodies within blisters and paleosurface-parallel crack-sheets of the older flow, rather than at the contact between flows; and 4) physical connection between paleosurface-parallel sediment bodies and sediment bodies that cross-cutting the younger flow exhibiting post-emplacement features described above. Features that might be indicative of deposition at the land surface but are not include: 1) roots, which can penetrate for tens of meters through sediment

  11. Maximum Entropy in Drug Discovery

    Directory of Open Access Journals (Sweden)

    Chih-Yuan Tseng

    2014-07-01

    Full Text Available Drug discovery applies multidisciplinary approaches either experimentally, computationally or both ways to identify lead compounds to treat various diseases. While conventional approaches have yielded many US Food and Drug Administration (FDA-approved drugs, researchers continue investigating and designing better approaches to increase the success rate in the discovery process. In this article, we provide an overview of the current strategies and point out where and how the method of maximum entropy has been introduced in this area. The maximum entropy principle has its root in thermodynamics, yet since Jaynes’ pioneering work in the 1950s, the maximum entropy principle has not only been used as a physics law, but also as a reasoning tool that allows us to process information in hand with the least bias. Its applicability in various disciplines has been abundantly demonstrated. We give several examples of applications of maximum entropy in different stages of drug discovery. Finally, we discuss a promising new direction in drug discovery that is likely to hinge on the ways of utilizing maximum entropy.

  12. What controls the maximum magnitude of injection-induced earthquakes?

    Science.gov (United States)

    Eaton, D. W. S.

    2017-12-01

    Three different approaches for estimation of maximum magnitude are considered here, along with their implications for managing risk. The first approach is based on a deterministic limit for seismic moment proposed by McGarr (1976), which was originally designed for application to mining-induced seismicity. This approach has since been reformulated for earthquakes induced by fluid injection (McGarr, 2014). In essence, this method assumes that the upper limit for seismic moment release is constrained by the pressure-induced stress change. A deterministic limit is given by the product of shear modulus and the net injected fluid volume. This method is based on the assumptions that the medium is fully saturated and in a state of incipient failure. An alternative geometrical approach was proposed by Shapiro et al. (2011), who postulated that the rupture area for an induced earthquake falls entirely within the stimulated volume. This assumption reduces the maximum-magnitude problem to one of estimating the largest potential slip surface area within a given stimulated volume. Finally, van der Elst et al. (2016) proposed that the maximum observed magnitude, statistically speaking, is the expected maximum value for a finite sample drawn from an unbounded Gutenberg-Richter distribution. These three models imply different approaches for risk management. The deterministic method proposed by McGarr (2014) implies that a ceiling on the maximum magnitude can be imposed by limiting the net injected volume, whereas the approach developed by Shapiro et al. (2011) implies that the time-dependent maximum magnitude is governed by the spatial size of the microseismic event cloud. Finally, the sample-size hypothesis of Van der Elst et al. (2016) implies that the best available estimate of the maximum magnitude is based upon observed seismicity rate. The latter two approaches suggest that real-time monitoring is essential for effective management of risk. A reliable estimate of maximum

  13. Water management issues in the underground gasification of coal and the subsequent use of the voids for long-term carbon dioxide storage

    Energy Technology Data Exchange (ETDEWEB)

    Younger, P.L. [Newcastle Univ., Newcastle Upon Tyne (United Kingdom). Newcastle Inst. for Research on Sustainability; Gonzalez, G. [Newcastle Univ., Newcastle Upon Tyne (United Kingdom). Sir Joseph Swan Inst. for Energy Research; Amezaga, J.M. [Newcastle Univ., Newcastle Upon Tyne (United Kingdom). School of Civil Engineering and Geosciences, Hydrogeochemical Engineering Research and Outreach

    2010-07-01

    A coupled underground coal gasification (UCG) and carbon capture and storage (CCS) technology was discussed. The technologies can be coupled so that voids created by mining can be uses as carbon dioxide (CO{sub 2}) storage sites. UCG involves the in-situ gasification of coal using directionally-drilled wells. The gasification is achieved by spontaneous combustion initiated by the injection of steam and oxygen. The rate of UCG is controlled by varying the availability of oxygen. The syngas produced during the process is drawn to the surface via neighbouring production boreholes where it can then be transported by pipeline for use in range of applications. Voids created by the UCG process will collapse, leaving high permeability zones isolated from the surface by low permeability superincumbent strata. The UCG goaf and relaxed roof strata will have permeabilities 1 to 3 orders of magnitude greater than the permeabilities of deep saline aquifers or hydrocarbon reservoirs. The void volume needed to store the CO{sub 2} produced from the syngas can be 4 or 5 times the volume occupied by the extracted coal. Risks for groundwater arising from UCG are groundwater depletion, contamination, and gas leakage. Prudent site selection and the use of an effective risk assessment framework are needed to ensure the successful implementation of UCG-CCS processes. 11 refs., 2 figs.

  14. Near infrared spectroscopy evaluation of bladder function: the impact of skin pigmentation on detection of physiologic change during voiding

    Science.gov (United States)

    Shadgan, Babak; Stothers, Lynn; Molavi, Behnam; Mutabazi, Sharif; Mukisa, Ronald; Macnab, Andrew

    2015-02-01

    Background: Prior research indicates the epidermal pigment layer of human skin (Melanin) has a significant absorption coefficient in the near infra-red (NIR) region; hence attenuation of light in vivo is a potential confounder for NIR spectroscopy (NIRS). A NIRS method developed for transcutaneous evaluation of bladder function is being investigated as a means of improving the burden of bladder disease in sub-Saharan Africa. This required development of a simple wireless NIRS device suitable for use as a screening tool in patients with pigmented skin where the NIR light emitted would penetrate through the epidermal pigment layer and return in sufficient quantity to provide effective monitoring. Methods: Two healthy subjects, one with pigmented skin and one with fair skin, were monitored as they voided spontaneously using the prototype transcutaneous NIRS device positioned over the bladder. The device was a self-contained wireless unit with light emitting diodes (wavelengths 760 and 850 nanometres) and interoptode distance of 4cm. The raw optical data were transmitted to a laptop where graphs of chromophore change were generated with proprietary software and compared between the subjects and with prior data from asymptomatic subjects. Results: Serial monitoring was successful in both subjects. Voiding volumes varied between 350 and 380 cc. In each subject the patterns of chromophore change, trend and magnitude of change were similar and matched the physiologic increase in total and oxygenated hemoglobin recognized to occur in normal bladder contraction during voiding. Conclusions: Skin pigmentation does not compromise the ability of transcutaneous NIRS to interrogate physiologic change in the bladder during bladder contraction in healthy subjects.

  15. Void Shapes Controlled by Using Interruption-Free Epitaxial Lateral Overgrowth of GaN Films on Patterned SiO2 AlN/Sapphire Template

    Directory of Open Access Journals (Sweden)

    Yu-An Chen

    2014-01-01

    Full Text Available GaN epitaxial layers with embedded air voids grown on patterned SiO2 AlN/sapphire templates were proposed. Using interruption-free epitaxial lateral overgrowth technology, we realized uninterrupted growth and controlled the shape of embedded air voids. These layers showed improved crystal quality using X-ray diffraction and measurement of etching pits density. Compared with conventional undoped-GaN film, the full width at half-maximum of the GaN (0 0 2 and (1 0 2 peaks decreased from 485 arcsec to 376 arcsec and from 600 arcsec to 322 arcsec, respectively. Transmission electron microscopy results showed that the coalesced GaN growth led to bending threading dislocation. We also proposed a growth model based on results of scanning electron microscopy.

  16. Modification of redshift and luminosity by voids in the expanding universe

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Humitaka

    1985-03-01

    Propagation of light in a clumpy universe is examined for redshift and luminosity. Taking a spherical void model and Swiss Chesse model, the modification is found to be the third order of (Hrsub(b)/c) for the redshift and the first order of it for the luminosity, rsub(b) being the radius of a void or a Swiss Cheese hole.

  17. 21 CFR 1305.19 - Cancellation and voiding of DEA Forms 222.

    Science.gov (United States)

    2010-04-01

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

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

    DEFF Research Database (Denmark)

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

    1990-01-01

    Results of measurements performed on a large open void, where pressure can be controlled from the outside, are compared to the theory of ultrasound transmission. The results verify the theory that the attenuation of transmitted ultrasonic signals through a void depends on the gas pressure inside ...

  19. Computer simulation of void formation in residual gas atom free metals by dual beam irradiation experiments

    International Nuclear Information System (INIS)

    Shimomura, Y.; Nishiguchi, R.; La Rubia, T.D. de; Guinan, M.W.

    1992-01-01

    In our recent experiments (1), we found that voids nucleate at vacancy clusters which trap gas atoms such as hydrogen and helium in ion- and neutron-irradiated copper. A molecular dynamics computer simulation, which implements an empirical embedded atom method to calculate forces that act on atoms in metals, suggests that a void nucleation occurs in pure copper at six and seven vacancy clusters. The structure of six and seven vacancy clusters in copper fluctuates between a stacking fault tetrahedron and a void. When a hydrogen is trapped at voids of six and seven vacancy, a void can keep their structure for appreciably long time; that is, the void do not relax to a stacking fault tetrahedron and grows to a large void. In order to explore the detailed atomics of void formation, it is emphasized that dual-beam irradiation experiments that utilize beams of gas atoms and self-ions should be carried out with residual gas atom free metal specimens. (author)

  20. A variational constitutive model for the distribution and interactions of multi-sized voids

    KAUST Repository

    Liu, Jinxing; El Sayed, Tamer S.

    2013-01-01

    of the radii of the voids. In this study, we use a new form of the incompressibility of the matrix to propose the formula for the volumetric plastic energy of a void inside a porous medium. As a consequence, we are able to account for the weakening effect

  1. The Effects of Void on Natural Ventilation Performance in Multi-Storey Housing

    Directory of Open Access Journals (Sweden)

    Fakhriah Muhsin

    2016-08-01

    Full Text Available Enhancing natural ventilation performance in multi-storey housing is very important for the living environment in terms of health and thermal comfort purposes. One of the most important design strategies to enhance natural ventilation in multi-storey housing is through the provision of voids. A void is a passive architectural feature, which is located in the middle of deep plan buildings. It is very crucial to consider the configurations of voids in the buildings for enhancing natural ventilation, especially for multi-storey housing. In this study, Malaysian Medium Cost Multi-Storey Housing (MMCMSH, which is an example of multi-storey housing located in a suburban area, has been selected in this study. This study aims to investigate the potential of void for enhancing natural ventilation performance in multi-storey housing by the comparison of two different void configurations. Field measurement of MMCMSH has been conducted to validate Computational Fluid Dynamic (CFD model and Atmospheric Boundary Layer (ABL is an important parameter for setting up the CFD Model’s domain. Ventilation rate (Q, which is necessary for comfort and health reasons, is an important parameter for the comparison of the different void configurations. This study revealed that the provision of void can enhance natural ventilation performance in multi-storey housing with an increase in the value of Q, from 3.44% to 40.07%, by enlarging the void’s width by 50% compared to the existing void.

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

    NARCIS (Netherlands)

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

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

  3. Effect of grain size on void swelling in irradiated materials: A phase-field approach

    International Nuclear Information System (INIS)

    Chang, Kunok; Lee, Gyeonggeun; Kwon, Junhyun

    2014-01-01

    The progress of swelling is retarded as the average grain diameter increases in a pure copper case. Within the framework of the production bias model (PBM), their experimental results were quantitatively explained. The phase-field method has already been used to investigate the void/bubble behavior in the irradiated materials. In particular, Millett et al. already incorporated the interaction between the point defect and the grain boundary in their study. Therefore, they described the void denuded zones and void peaked zones adjacent to the grain boundaries, which are already observed in the experimental investigations. We performed the phase-field simulation in order to verify the role of the grain diameter on the void swelling in the cascade damage condition. In addition, our results will be compared with the experimental observations or the theoretical works, such as PBM. Two-dimensional phase-field simulations were performed to investigate the void swelling process in the irradiated materials. We clearly observed the void denuded and void peaked zones, which were already observed in formal experimental and computational approaches. We also found that the progress of swelling was retarded as the average grain diameter increased. The triple junctions, which are believed to be a critical factor t affecting the fracture, are the main cites for the void nucleation and growth in our simulations

  4. Void fraction distribution in a heated rod bundle under flow stagnation conditions

    Energy Technology Data Exchange (ETDEWEB)

    Herrero, V.A.; Guido-Lavalle, G.; Clausse, A. [Centro Atomico Bariloche and Instituto Balseiro, Bariloche (Argentina)

    1995-09-01

    An experimental study was performed to determine the axial void fraction distribution along a heated rod bundle under flow stagnation conditions. The development of the flow pattern was investigated for different heat flow rates. It was found that in general the void fraction is overestimated by the Zuber & Findlay model while the Chexal-Lellouche correlation produces a better prediction.

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

    Science.gov (United States)

    Das, Rebekah N; Grimmer-Somers, Karen A

    2012-01-01

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

  6. Microscopic Void Detection for Predicting Remaining Life in Electric Cable Insulation

    International Nuclear Information System (INIS)

    Horvath, David A.; Avila, Steven M.

    2003-01-01

    A reliable method of testing for remaining life in electric cable insulation has continued to elude the nuclear industry as it seeks to extend the life and license of its nuclear stations. Until recently, a trendable, measurable electrical property has not been found, and unexpected cable failures continue to be reported. Most reliable approaches to date rely on monitoring mechanical properties, which are assumed to degrade faster than the insulation's electrical properties. This paper introduces a promising technique based on void characterization, which is dependent on an electrical property related to dielectric strength. A relationship between insulation void characteristics (size and density) and the onset of partial discharge is known to exist. A similar relationship can be shown between void characteristics and unacceptable leakage currents (another typical cable failure criterion). For low-voltage cables, it is believed void content can be correlated to mechanical property degradation.This paper will report on an approach for using void information, research results showing the existence of trendable void characteristics in commonly used electric insulation materials, and techniques for detecting the voids (both laboratory- and field-based techniques). Acoustical microscopy was found to be potentially more suitable than conventional ultrasound for nondestructive in situ detection and monitoring of void characteristics in jacketed multiconductor insulation while ignoring the jacket. Also, optical and scanning electron microscope techniques will play an essential role in establishing the database necessary for continued development and implementation of this promising technique

  7. PD-related stresses in the bulk dielectric for ellipsoidal voids

    DEFF Research Database (Denmark)

    Pedersen, Aage; Crichton, George C; McAllister, Iain Wilson

    1994-01-01

    In a previous study, the existence of a field enhancement in the solid dielectric in the vicinity of void undergoing PD activity was established. That study was undertaken with reference to a spherical void. In this paper, a more general investigation of this phenomenon of field enhancement...

  8. Radiation-induced segregation and void formation in C+ ion-irradiated vanadium-carbon alloys

    International Nuclear Information System (INIS)

    Takeyama, T.; Ohnuki, S.; Takahashi, H.; Sato, Y.; Mochizuki, S.

    1982-01-01

    To clarify the effect of interstitial elements on radiation-induced segregation and void formation in V and V-C alloys irradiated by 200 keV C + ions to a dose of 48 dpa at 973 K, the microstructural observation and the measurement of C segregation to the surfaces were carried out by TEM and XPS. Voids, dislocations and precipitates were produced in all of the specimens during irradiation. The addition of C in V led to a reduction of void size and to increase in void number density, consequently the void swelling was suppressed strongly. Radiation-induced segregation of C was observed clearly on and near the irradiated surfaces of V-C alloys and as a result of the enrichment of C atoms, carbides precipitated on the surfaces. It is the first evidence of the radiation-induced segregation of interstitial elements on the surfaces. Also, quasi-carbides were observed on the (210) habit plaints near large voids and dislocations in V. The phenomena show that C atoms, which was insolved and/or implanted, interact strongly with vacancies rather than self-interstitial atoms and migrate with vacancies toward defect sinks, such as surfaces, voids, and dislocations. The segregated zones of C reduced the sink efficiency of the defects, and showed the effect of the suppression on void in V-C alloys. (author)

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

    International Nuclear Information System (INIS)

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

    2001-03-01

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

  10. [Specialized outpatient care in the Unified Health System: how to fill a void].

    Science.gov (United States)

    Tesser, Charles Dalcanale; Poli, Paulo

    2017-03-01

    The structuring of specialized outpatient care is a bottleneck in the operation of the Unified Health System. Based on a brief discussion about this void in an organizational model, we propose the federal induction of a format of specialized services from the experiences of Centers of Support for Family Health (NASF). They adapted matrix operations and constitute an excellent prototype for the organization of specialized outpatient care. It allows for equal access and maximum proximity to the specialized care of the reality of primary care users, the personal relationship and the close relationship between the family health teams and medical and non-medical specialists, enabling mutual lifelong learning, negotiated regulation and increased efficacy of primary care. Municipal experiences of Florianopolis and Curitiba are synthesized as partial examples of the proposal. the structure of care in mental health of Florianópolis, all organized as a matrix support is briefly described; and we focus on the change in the action of the support teams of Curitiba, which gradually began to engage, involve and mediate the relationship between basic and specialized care. This format can be expanded to most medical specialties.

  11. Void reactivity decomposition for the Sodium-cooled Fast Reactor in equilibrium fuel cycle

    Energy Technology Data Exchange (ETDEWEB)

    Sun Kaichao, E-mail: kaichao.sun@psi.ch [Paul Scherrer Institut (PSI), 5232 Villigen PSI (Switzerland); Ecole Polytechnique Federale de Lausanne (EPFL), 1015 Lausanne (Switzerland); Krepel, Jiri; Mikityuk, Konstantin; Pelloni, Sandro [Paul Scherrer Institut (PSI), 5232 Villigen PSI (Switzerland); Chawla, Rakesh [Paul Scherrer Institut (PSI), 5232 Villigen PSI (Switzerland); Ecole Polytechnique Federale de Lausanne (EPFL), 1015 Lausanne (Switzerland)

    2011-07-15

    Highlights: > We analyze the void reactivity effect for three ESFR core fuel cycle states. > The void reactivity effect is decomposed by neutron balance method. > Novelly, the normalization to the integral flux in the active core is applied. > The decomposition is compared with the perturbation theory based results. > The mechanism and the differences of the void reactivity effect are explained. - Abstract: The Sodium-cooled Fast Reactor (SFR) is one of the most promising Generation IV systems with many advantages, but has one dominating neutronic drawback - a positive sodium void reactivity. The aim of this study is to develop and apply a methodology, which should help better understand the causes and consequences of the sodium void effect. It focuses not only on the beginning-of-life (BOL) state of the core, but also on the beginning of open and closed equilibrium (BOC and BEC, respectively) fuel cycle conditions. The deeper understanding of the principal phenomena involved may subsequently lead to appropriate optimization studies. Various voiding scenarios, corresponding to different spatial zones, e.g. node or assembly, have been analyzed, and the most conservative case - the voiding of both inner and outer fuel zones - has been selected as the reference scenario. On the basis of the neutron balance method, the corresponding SFR void reactivity has been decomposed reaction-, isotope-, and energy-group-wise. Complementary results, based on generalized perturbation theory and sensitivity analysis, are also presented. The numerical analysis for both neutron balance and perturbation theory methods has been carried out using appropriate modules of the ERANOS code system. A strong correlation between the flux worth, i.e. the product of flux and adjoint flux, and the void reactivity importance distributions has been found for the node- and assembly-wise voiding scenarios. The neutron balance based decomposition has shown that the void effect is caused mainly by the

  12. Void reactivity decomposition for the Sodium-cooled Fast Reactor in equilibrium fuel cycle

    International Nuclear Information System (INIS)

    Sun Kaichao; Krepel, Jiri; Mikityuk, Konstantin; Pelloni, Sandro; Chawla, Rakesh

    2011-01-01

    Highlights: → We analyze the void reactivity effect for three ESFR core fuel cycle states. → The void reactivity effect is decomposed by neutron balance method. → Novelly, the normalization to the integral flux in the active core is applied. → The decomposition is compared with the perturbation theory based results. → The mechanism and the differences of the void reactivity effect are explained. - Abstract: The Sodium-cooled Fast Reactor (SFR) is one of the most promising Generation IV systems with many advantages, but has one dominating neutronic drawback - a positive sodium void reactivity. The aim of this study is to develop and apply a methodology, which should help better understand the causes and consequences of the sodium void effect. It focuses not only on the beginning-of-life (BOL) state of the core, but also on the beginning of open and closed equilibrium (BOC and BEC, respectively) fuel cycle conditions. The deeper understanding of the principal phenomena involved may subsequently lead to appropriate optimization studies. Various voiding scenarios, corresponding to different spatial zones, e.g. node or assembly, have been analyzed, and the most conservative case - the voiding of both inner and outer fuel zones - has been selected as the reference scenario. On the basis of the neutron balance method, the corresponding SFR void reactivity has been decomposed reaction-, isotope-, and energy-group-wise. Complementary results, based on generalized perturbation theory and sensitivity analysis, are also presented. The numerical analysis for both neutron balance and perturbation theory methods has been carried out using appropriate modules of the ERANOS code system. A strong correlation between the flux worth, i.e. the product of flux and adjoint flux, and the void reactivity importance distributions has been found for the node- and assembly-wise voiding scenarios. The neutron balance based decomposition has shown that the void effect is caused mainly

  13. Thermal behaviour of pressure tube under fully and partially voided heating conditions using 19 pin fuel element simulator

    International Nuclear Information System (INIS)

    Yadav, Ashwini K.; Kumar, Ravi; Gupta, Akhilesh; Chatterjee, B.; Mukhopadhya, D.; Lele, H.G.

    2011-01-01

    In a nuclear reactor temperature can rise drastically during LOCA due to failure of heat transportation system and subsequently leads to mechanical deformations like sagging, ballooning and breaching of pressure tube. To understand the phenomenon an experiment has been carried out using 19 pin fuel element simulator. Main purpose of the experiment was to trace temperature profiles over the pressure tube, calandria tube and clad tubes of 220 MWe Indian Pressurised Heavy Water Reactor (IPHWR). The symmetrical heating of pressure tube of 1 m length was done through resistance heating of 19 pins under 13.5 kW power using a rectifier and the variation of temperatures over the circumference of pressure tube (PT), calandria tube (CT) and clad tubes were measured. The sagging of pressure tube was initiated at 460 deg C temperature and highest temperature attained was 650 deg C. The highest temperature attained by clad tubes was 680 deg C (over outer ring) and heat is dissipated to calandria vessel mainly due to radiation and natural convection. Again to simulate partially voided conditions, asymmetrical heating of pressure was carried out by injecting 8 kW power to upper 8 pins of fuel simulator. A maximum temperature difference of 295 deg C was observed over the circumference of pressure tube which highlights the magnitude of thermal stresses and its role in breaching of pressure tube under partially voided conditions. Integrity of pressure tube was retained during both symmetrical and asymmetrical heatup conditions. (author)

  14. The influence of different loads on the remodeling process of a bone and bioresorbable material mixture with voids

    Science.gov (United States)

    Giorgio, Ivan; Andreaus, Ugo; Madeo, Angela

    2016-03-01

    A model of a mixture of bone tissue and bioresorbable material with voids was used to numerically analyze the physiological balance between the processes of bone growth and resorption and artificial material resorption in a plate-like sample. The adopted model was derived from a theory for the behavior of porous solids in which the matrix material is linearly elastic and the interstices are void of material. The specimen—constituted by a region of bone living tissue and one of bioresorbable material—was acted by different in-plane loading conditions, namely pure bending and shear. Ranges of load magnitudes were identified within which physiological states become possible. Furthermore, the consequences of applying different loading conditions are examined at the end of the remodeling process. In particular, maximum value of bone and material mass densities, and extensions of the zones where bone is reconstructed were identified and compared in the two different load conditions. From the practical view point, during surgery planning and later rehabilitation, some choice of the following parameters is given: porosity of the graft, material characteristics of the graft, and adjustment of initial mixture tissue/bioresorbable material and later, during healing and remodeling, optimal loading conditions.

  15. Maximum stellar iron core mass

    Indian Academy of Sciences (India)

    60, No. 3. — journal of. March 2003 physics pp. 415–422. Maximum stellar iron core mass. F W GIACOBBE. Chicago Research Center/American Air Liquide ... iron core compression due to the weight of non-ferrous matter overlying the iron cores within large .... thermal equilibrium velocities will tend to be non-relativistic.

  16. Maximum entropy beam diagnostic tomography

    International Nuclear Information System (INIS)

    Mottershead, C.T.

    1985-01-01

    This paper reviews the formalism of maximum entropy beam diagnostic tomography as applied to the Fusion Materials Irradiation Test (FMIT) prototype accelerator. The same formalism has also been used with streak camera data to produce an ultrahigh speed movie of the beam profile of the Experimental Test Accelerator (ETA) at Livermore. 11 refs., 4 figs

  17. Maximum entropy beam diagnostic tomography

    International Nuclear Information System (INIS)

    Mottershead, C.T.

    1985-01-01

    This paper reviews the formalism of maximum entropy beam diagnostic tomography as applied to the Fusion Materials Irradiation Test (FMIT) prototype accelerator. The same formalism has also been used with streak camera data to produce an ultrahigh speed movie of the beam profile of the Experimental Test Accelerator (ETA) at Livermore

  18. A portable storage maximum thermometer

    International Nuclear Information System (INIS)

    Fayart, Gerard.

    1976-01-01

    A clinical thermometer storing the voltage corresponding to the maximum temperature in an analog memory is described. End of the measurement is shown by a lamp switch out. The measurement time is shortened by means of a low thermal inertia platinum probe. This portable thermometer is fitted with cell test and calibration system [fr

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

    CERN Document Server

    Hudson, T S; Sutton, A P

    2002-01-01

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

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

    KAUST Repository

    Elrasad, Amr; Shihada, Basem

    2015-01-01

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