Assessment of consistent two-equation closure for forest flows

DEFF Research Database (Denmark)

Sogachev, Andrey; Cavar, Dalibor; Bechmann, Andreas

of grid turbulence and wall-bounded flow, the closure suggested is also valid for homogeneous shear flows commonly observed inside tall vegetative canopies. The present work assess the plant drag closure by comparing results of two different CFD models against observations derived over the forested area...... and can be applied for any twoequation closure. Results derived by different CFD models with k-epsilon and k-omega closure are similar and in good comparison with observations. Overall, numerical results show that the closure performs well, opening new possibilities for application to tasks related...... to the atmospheric boundary layer—where it is important to adequately account for the influences of vegetation....

Carpe diem, Carpe ampulla: a numerical model as an aid to the design of child-resistant closures.

Science.gov (United States)

Yoxall, A; Rodriguez-Falcon, E M; Luxmoore, J

2013-01-01

The population of most developed countries is ageing. Despite continuing medical advances, ageing brings with it a host of issues, not least a loss in strength and dexterity. One major area of concern is the ability of elderly consumers to access packaged goods such as food and medicines. In previous studies, the authors developed a numerical model of a human hand that was used to investigate the effect of physical dimensions and choice of grip on joint stresses to aid the understanding between physical effort, ability and discomfort. This previous work was supported by ethnographic studies and led to recommendations for packaging design. In this paper, a small ethnographic study is undertaken which identifies the grip types used to access to a product that is known to cause particular difficulties for the elderly, the "squeeze and turn" child-resistant closure or CRC, commonly used on medicines and cleaning products. One of the grip types used was chosen to be modelled using the numerical model developed in previous studies by the author. Model geometry and loading were adapted to simulate the "squeeze and turn" nature of the initial opening for closures of this type. A series of studies were then undertaken using different hand geometries; an average male hand, an average female hand and a fifth percentile female hand. The prediction from the model here is that female users with smaller hands will experience more discomfort when accessing squeeze and turn CRC's and that the turn process whilst maintaining the squeeze is problematic. Copyright © 2012 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Comparison of Outcomes between Early Fascial Closure and Delayed Abdominal Closure in Patients with Open Abdomen: A Systematic Review and Meta-Analysis

Directory of Open Access Journals (Sweden)

Yu Chen

2014-01-01

Full Text Available Up to the present, the optimal time to close an open abdomen remains controversial. This study was designed to evaluate whether early fascial abdominal closure had advantages over delayed approach for open abdomen populations. Medline, Embase, and Cochrane Library were searched until April 2013. Search terms included “open abdomen,” “abdominal compartment syndrome,” “laparostomy,” “celiotomy,” “abdominal closure,” “primary,” “delayed,” “permanent,” “fascial closure,” and “definitive closure.” Open abdomen was defined as “fail to close abdominal fascia after a laparotomy.” Mortality, complications, and length of stay were compared between early and delayed fascial closure. In total, 3125 patients were included for final analysis, and 1942 (62% patients successfully achieved early fascial closure. Vacuum assisted fascial closure had no impact on pooled fascial closure rate. Compared with delayed abdominal closure, early fascial closure significantly reduced mortality (12.3% versus 24.8%, RR, 0.53, P<0.0001 and complication incidence (RR, 0.68, P<0.0001. The mean interval from open abdomen to definitive closure ranged from 2.2 to 14.6 days in early fascial closure groups, but from 32.5 to 300 days in delayed closure groups. This study confirmed clinical advantages of early fascial closure over delayed approach in treatment of patients with open abdomen.

Early experience with the Occlutech PLD occluder for mitral paravalvar leak closure through a hybrid transapical approach.

Science.gov (United States)

Bedair, Radwa; Morgan, Gareth J; Bapat, Vinayak; Kapetanakis, Stamatis; Goreczny, Sebastian; Simpson, John; Qureshi, Shakeel A

2016-12-10

We sought to evaluate the feasibility and efficacy of hybrid transapical closure of paravalvar mitral leaks using a new Occlutech PLD occluder in patients with heart failure and/or haemolytic anaemia. Retrospective analysis of clinical and procedural data was undertaken for patients who had attempted closure of paravalvar mitral leaks via a hybrid transapical approach with the Occlutech PLD occluder. Eight patients (four males, median age 69 years) underwent closure of 10 mitral paravalvar leaks using eight Occlutech PLD occluders and two AMPLATZER Vascular Plugs (AVP II). Successful deployment, with significant reduction of the paravalvar leak was achieved in seven patients with short procedure (median 131 min) and fluoroscopy times (median 22 min). One patient had mechanical interference with prosthetic valve function, requiring surgery. Another patient with a high EuroSCORE (48.8%) died of multi-organ failure two days after the procedure. Clinical improvement in either heart failure or haemolysis was seen in all discharged patients. In our series of patients with challenging anatomy, the Occlutech PLD occluders performed well when implanted via a hybrid transapical approach. Further work is needed to assess this methodology fully for a wider population and to assess other deployment approaches for this promising new occluder.

The exploration of the closure of patent ductus arteriosus with Amplatzer occluder through single venous approach under ultrasound monitoring

International Nuclear Information System (INIS)

Luo Guoxin; He Jianxin; Li Guoying; Gong Zhihua; Wen Yanfei

2011-01-01

Objective: To explore the feasibility and effectiveness of transcatheter closure of patent ductus arteriosus (PDA) with Amplatzer occluder by using single venous approach method under ultrasound monitoring. Methods: During the period from May 2003 to April 2010, transcatheter closure of PDA were performed in 123 cases. Of the 123 patients, the procedure was accomplished by using arteriovenous dual approach method in 46 and by using single venous approach method in 77. All the procedures were monitored by ultrasound. The shape, size of PDA and immediate therapeutic results were checked with angiography in arteriovenous dual approach method or with ultrasonography in single venous approach method. The size of Amplatzer occluder was individually selected according to the smallest diameter of PDA. Echocardiography was performed at 3 days, one, 6 and 12 months after the procedure to evaluate the results. Results: Successful device placement with the initially selected occluder was obtained in 118 cases. In 4 cases the procedure was eventually completed after a bigger occluder was employed to replace the initial one, while in one case a smaller occluder had to use to replace the first one. The technical success rate was 100%. Conclusion: The transcatheter closure of PDA with Amplatzer occluder under ultrasound monitoring by single venous approach method is clinically effective and feasible. Being technically simple and time-saving, this single venous approach method is of great value in clinical practice. (authors)

Occupancy estimation and the closure assumption

Science.gov (United States)

Rota, Christopher T.; Fletcher, Robert J.; Dorazio, Robert M.; Betts, Matthew G.

2009-01-01

1. Recent advances in occupancy estimation that adjust for imperfect detection have provided substantial improvements over traditional approaches and are receiving considerable use in applied ecology. To estimate and adjust for detectability, occupancy modelling requires multiple surveys at a site and requires the assumption of 'closure' between surveys, i.e. no changes in occupancy between surveys. Violations of this assumption could bias parameter estimates; however, little work has assessed model sensitivity to violations of this assumption or how commonly such violations occur in nature. 2. We apply a modelling procedure that can test for closure to two avian point-count data sets in Montana and New Hampshire, USA, that exemplify time-scales at which closure is often assumed. These data sets illustrate different sampling designs that allow testing for closure but are currently rarely employed in field investigations. Using a simulation study, we then evaluate the sensitivity of parameter estimates to changes in site occupancy and evaluate a power analysis developed for sampling designs that is aimed at limiting the likelihood of closure. 3. Application of our approach to point-count data indicates that habitats may frequently be open to changes in site occupancy at time-scales typical of many occupancy investigations, with 71% and 100% of species investigated in Montana and New Hampshire respectively, showing violation of closure across time periods of 3 weeks and 8 days respectively. 4. Simulations suggest that models assuming closure are sensitive to changes in occupancy. Power analyses further suggest that the modelling procedure we apply can effectively test for closure. 5. Synthesis and applications. Our demonstration that sites may be open to changes in site occupancy over time-scales typical of many occupancy investigations, combined with the sensitivity of models to violations of the closure assumption, highlights the importance of properly addressing

Contemporary Approach to the Diagnosis and Management of Primary Angle-Closure Disease.

Science.gov (United States)

Razeghinejad, M Reza; Myers, Jonathan S

2018-05-16

Primary angle closure disease spectrum varies from a narrow angle to advanced glaucoma. A variety of imaging technologies may assist the clinician in determining the pathophysiology and diagnosis of primary angle closure, but gonioscopy remains a mainstay of clinical evaluation. Laser iridotomy effectively eliminates the pupillary block component of angle closure; however, studies show that in many patients the iridocorneal angle remains narrow from underlying anatomic issues, and increasing lens size often leads to further narrowing over time. Recent studies have further characterized the role of the lens in angle closure disease, and cataract or clear lens extraction is increasingly used earlier in its management. As a first surgical step in angle closure glaucoma, lens extraction alone often effectively controls the pressure with less risk of complications than concurrent or stand alone glaucoma surgery, but may not be sufficient in more advanced or severe disease. We provide a comprehensive review on the primary angle-closure disease nomenclature, imaging, and current laser and surgical management. Copyright © 2018. Published by Elsevier Inc.

Analysis of Mining-induced Valley Closure Movements

Science.gov (United States)

Zhang, C.; Mitra, R.; Oh, J.; Hebblewhite, B.

2016-05-01

Valley closure movements have been observed for decades in Australia and overseas when underground mining occurred beneath or in close proximity to valleys and other forms of irregular topographies. Valley closure is defined as the inward movements of the valley sides towards the valley centreline. Due to the complexity of the local geology and the interplay between several geological, topographical and mining factors, the underlying mechanisms that actually cause this behaviour are not completely understood. A comprehensive programme of numerical modelling investigations has been carried out to further evaluate and quantify the influence of a number of these mining and geological factors and their inter-relationships. The factors investigated in this paper include longwall positional factors, horizontal stress, panel width, depth of cover and geological structures around the valley. It is found that mining in a series passing beneath the valley dramatically increases valley closure, and mining parallel to valley induces much more closure than other mining orientations. The redistribution of horizontal stress and influence of mining activity have also been recognised as important factors promoting valley closure, and the effect of geological structure around the valley is found to be relatively small. This paper provides further insight into both the valley closure mechanisms and how these mechanisms should be considered in valley closure prediction models.

A regenerative approach towards mucosal fenestration closure

Science.gov (United States)

Gandi, Padma; Anumala, Naveen; Reddy, Amarender; Viswa Chandra, Rampalli

2013-01-01

Mucosal fenestration is an opening or an interstice through the oral mucosa. A lesion which occurs with greater frequency than generally realised, its occurrence is attributed to a myriad of causes. Mucogingival procedures including connective tissue grafts, free gingival grafts and lateral pedicle grafts are generally considered to be the treatment of choice in the closure of a mucosal fenestration. More often, these procedures are performed in conjunction with other procedures such as periradicular surgery and with bone grafts. However, the concomitant use of gingival grafts and bone grafts in mucosal fenestrations secondary to infections in sites exhibiting severe bone loss is highly debatable. In this article, we report two cases of mucosal fenestrations secondary to trauma and their management by regenerative periodontal surgery with the placement of guided tissue regeneration membrane and bone graft. The final outcome was a complete closure of the fenestration in both the cases. PMID:23749826

Catheter Closure Through a Venous Approach of Patent Ductus Arteriosus in Small Pediatric Patients Using Combined Angiographic and Echocardiographic Guidance.

Science.gov (United States)

Thanopoulos, Basil Vasilios D; Ninios, Vlassis; Dardas, Petros; Giannopoulos, Andreas; Deleanou, Dan; Iancovici, Silvia

2016-11-15

The standard technique of catheter closure of patent ductus arteriosus (PDA) may be associated with arterial complications particularly in small pediatric patients. The aim of this study was to evaluate whether catheter closure of PDA in small children using an exclusive venous approach is a safe and effective alternative to closure with the standard technique. One hundred-twelve patients, aged 2 to 24 months, were randomly assigned in a 1:1 ratio to catheter closure of PDA using the standard technique (group 1) and an exclusive venous approach (group 2), respectively. In group 2, the procedure was guided using hand injections of contrast media through the delivery sheath and 2-dimensional and color Doppler echocardiography. Group 1: the PDA diameter ranged from 2 to 5.5 mm and the device diameter ranged from 4 to 8 mm. The PDA occluders were permanently implanted in all patients. Five losses of the arterial pulses that were restored with intravenous infusion of heparin and recombinant tissue plasminogen activator (rtPA), and 4 groin hematomas were the main complications of the procedure. Group 2: the mean PDA diameter ranged from 2.5 to 6 mm and the device diameter ranged from 3 to 8 mm. The PDA occluders were permanently implanted in all but 2 patients. There were no complications. Complete echocardiographic closure of PDA at 1-month follow-up was observed in all 110 patients. Exclusive transvenous PDA occlusion is an effective and safe technique that prevents the arterial complications of the standard approach in small children. Copyright © 2016 Elsevier Inc. All rights reserved.

Risk-based approach to appraise valve closure in the clam Corbicula fluminea in response to waterborne metals

International Nuclear Information System (INIS)

Liao, C.-M.; Jou, L.-J.; Chen, B.-C.

2005-01-01

We developed a risk-based approach to assess how the valve closure behavior of Asiatic clam Corbicula fluminea responds to waterborne copper (Cu) and cadmium (Cd). We reanalyzed the valve closure response data from published literature to reconstruct the response time-dependent dose-response profiles based on an empirical three-parameter Hill equation model. We integrated probabilistic exposure profiles of measured environmental Cu and Cd concentrations in the western coastal areas of Taiwan with the reconstructed dose-response relationships at different integration times of response to quantitatively estimate the valve response risk. The risk assessment results implicate exposure to waterborne Cu and Cd may pose no significant risk to clam valve activity in the short-time response periods (e.g., <30 min), yet a relative high risk for valve closure response to waterborne Cu at response times greater than 120 min is alarming. We successfully linked reconstructed dose-response profiles and EC50-time relationships associated with the fitted daily valve opening/closing rhythm characterized by a three-parameter lognormal function to predict the time-varying bivalve closure rhythm response to waterborne metals. We parameterized the proposed predictive model that should encourage a risk-management framework for discussion of future design of biological monitoring systems. - A model was developed to link valve closure in clams to concentrations of metals in water

A novel numerical approach for workspace determination of parallel mechanisms

Energy Technology Data Exchange (ETDEWEB)

Zhou, Yiqun; Niu, Junchuan; Liu, Zhihui; Zhang, Fuliang [Shandong University, Shandong (China)

2017-06-15

In this paper, a novel numerical approach is proposed for workspace determination of parallel mechanisms. Compared with the classical numerical approaches, this presented approach discretizes both location and orientation of the mechanism simultaneously, not only one of the two. This technique makes the presented numerical approach applicable in determining almost all types of workspaces, while traditional numerical approaches are only applicable in determining the constant orientation workspace and orientation workspace. The presented approach and its steps to determine the inclusive orientation workspace and total orientation workspace are described in detail. A lower-mobility parallel mechanism and a six-degrees-of-freedom Stewart platform are set as examples, the workspaces of these mechanisms are estimated and visualized by the proposed numerical approach. Furthermore, the efficiency of the presented approach is discussed. The examples show that the presented approach is applicable in determining the inclusive orientation workspace and total orientation workspace of parallel mechanisms with high efficiency.

Some thermalhydraulics of closure head adapters in a 3 loops PWR

Energy Technology Data Exchange (ETDEWEB)

Hoffmann, F.; Daubert, O.; Hecker, M. [EDF/DER/National Hydraulics Laboratory, Chatou (France)] [and others

1995-09-01

In 1993 a R&D action, based on numerical simulations and experiments on PWR`s upper head was initiated. This paper presents the test facility TRAVERSIN (a scale model of a 900 MW PWR adapter) and the calculations performed on the geometry of different upper head sections with the Thermalhydraulic Finite Element Code N3S used for 2D and 3D computations. The paper presents the method followed to bring the adapter and upper head study to a successful conclusion. Two complementary approaches are performed to obtain global results on complete fluid flow in the upper head and local results on the flow around the adapters of closure head. A validation test case of these experimental and numerical tools is also presented.

Subcostal closure technique for prevention of postthoracotomy pain syndrome.

Science.gov (United States)

Hong, Kipyo; Bae, Mikyung; Han, Sora

2016-09-01

The purpose of this study was to evaluate the efficacy of our subcostal closure technique in prevention of postthoracotomy pain syndrome. From July 2012 to March 2015, 29 patients in whom a lobectomy was indicated underwent a thoracotomy. The thoracotomy wounds were closed using a subcostal closure technique (subcostal closure group) and outcomes were compared with 31 patients who underwent video-assisted thoracoscopic surgery (thoracoscopy group). The duration of oral opioid consumption was evaluated from medical records, and postoperative pain was evaluated by telephone interview conducted by a trained nurse practitioner who was unaware of the patient's group. Pain scores were higher in the thoracoscopy group compared to the subcostal closure group, reaching statistical significance (Numeric Rating Scale 0.55 ± 0.948 in the subcostal closure group vs. 1.84 ± 1.614 in the thoracoscopy group; p Pain Scale 0.24 ± 0.435 in the subcostal closure group vs. 0.81 ± 0.703 in the thoracoscopy group; p pain syndrome. © The Author(s) 2016.

A wavenumber-partitioning scheme for two-dimensional statistical closures

International Nuclear Information System (INIS)

Bowman, J.C.

1994-11-01

One of the principal advantages of statistical closure approximations for fluid turbulence is that they involve smoothly varying functions of wavenumber. This suggests the possibility of modeling a flow by following the evolution of only a few representative wavenumbers. This work presents two new techniques for the implementation of two-dimensional isotropic statistical closures that for the first time allows the inertial-range scalings of these approximation to be numerically demonstrated. A technique of wavenumber partitioning that conserves both energy and enstrophy is developed for two-dimensional statistical closures. Coupled with a new time-stepping scheme based on a variable integrating factor, this advance facilitates the computation of energy spectra over seven wavenumber decades, a task that will clearly remain outside the realm of conventional numerical simulations for the foreseeable future. Within the context of the test-field model, the method is used to demonstrate Kraichnan's logarithmically-corrected scaling for the enstrophy inertial range and to make a quantitative assessment of the effect of replacing the physical Laplacian viscosity with an enhanced hyperviscosity

Autonomic Closure for Turbulent Flows Using Approximate Bayesian Computation

Science.gov (United States)

Doronina, Olga; Christopher, Jason; Hamlington, Peter; Dahm, Werner

2017-11-01

Autonomic closure is a new technique for achieving fully adaptive and physically accurate closure of coarse-grained turbulent flow governing equations, such as those solved in large eddy simulations (LES). Although autonomic closure has been shown in recent a priori tests to more accurately represent unclosed terms than do dynamic versions of traditional LES models, the computational cost of the approach makes it challenging to implement for simulations of practical turbulent flows at realistically high Reynolds numbers. The optimization step used in the approach introduces large matrices that must be inverted and is highly memory intensive. In order to reduce memory requirements, here we propose to use approximate Bayesian computation (ABC) in place of the optimization step, thereby yielding a computationally-efficient implementation of autonomic closure that trades memory-intensive for processor-intensive computations. The latter challenge can be overcome as co-processors such as general purpose graphical processing units become increasingly available on current generation petascale and exascale supercomputers. In this work, we outline the formulation of ABC-enabled autonomic closure and present initial results demonstrating the accuracy and computational cost of the approach.

Some thermohydraulics of closure head adapters in a 3 loops PWR

International Nuclear Information System (INIS)

Hofmann, F.; Daubert, O.; Bertrand, C.; Hecker, M.; Arnoux-Guisse, F.; Bonnin, O.

1995-12-01

In 1993 a R and D action, based on numerical simulations and experiments on PWR's upper head was initiated. This paper presents the test facility TRAVERSIN (a scale model of a 900 MW adapter) and calculations performed on the geometry of different upper head sections with the Thermalhydraulic Finite Element Code N3S used for 2D and 3D computations. The paper presents the method followed to bring the adapter and upper head study to a successful conclusion. Two complementary approaches are performed to obtain global results on complete fluid flow in the upper head and local results on the flow around the adapters of closure head. A validation test case of these experimental and numerical tools is also presented. (authors). 7 refs., 9 figs., 1 tab

Analysis of the components of a pipeline closure as a unilateral confact problem

International Nuclear Information System (INIS)

Barbosa, H.J.C.; Feijoo, R.A.

1987-03-01

In many situations in the stress analysis of piping systems and pressure vessels the need to deal with (non-linear) unilateral contact problems arises. A typical case is the analysis of the components of pipe closure. In this work, numerical algorithms developed in previous publications are apllied in an example where the system composed by the closure neck, the blanking plug and the locking ring of a pipe closure is analysed. (Author) [pt

An approach to handling timescales in post-closure safety assessment

International Nuclear Information System (INIS)

Bailey, L.; Littleboy, A.

2002-01-01

Previous Nirex post-closure assessments of deep geological disposal have been based on the use of probabilistic safety analysis covering many millions of years. However, Nirex has also published an assessment methodology in which the assessment timescale is divided into a number of discrete periods of time (time frames). Nirex is currently at the stage of planning the next update to its generic post-closure performance assessment and is considering the merits of using an assessment methodology based on time frames, in order to improve links with operational assessments and the provision of advice on the packaging of wastes, and to encourage stakeholder dialogue. This paper has been prepared as part of Nirex's aim, wherever possible, to 'preview', or seek input from others on, its ideas for new work to generate discussion and feedback. It describes an evolution of Nirex's published assessment methodology and outlines how it could be applied in an updated post-closure performance assessment of the Nirex generic phased disposal concept. (authors)

RELAP-7 Closure Correlations

Energy Technology Data Exchange (ETDEWEB)

Zou, Ling [Idaho National Lab. (INL), Idaho Falls, ID (United States); Berry, R. A. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Martineau, R. C. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Andrs, D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Zhang, H. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Hansel, J. E. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Sharpe, J. P. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Johns, Russell C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-04-01

The RELAP-7 code is the next generation nuclear reactor system safety analysis code being developed at the Idaho National Laboratory (INL). The code is based on the INL’s modern scientific software development framework, MOOSE (Multi-Physics Object Oriented Simulation Environment). The overall design goal of RELAP-7 is to take advantage of the previous thirty years of advancements in computer architecture, software design, numerical integration methods, and physical models. The end result will be a reactor systems analysis capability that retains and improves upon RELAP5’s and TRACE’s capabilities and extends their analysis capabilities for all reactor system simulation scenarios. The RELAP-7 code utilizes the well-posed 7-equation two-phase flow model for compressible two-phase flow. Closure models used in the TRACE code has been reviewed and selected to reflect the progress made during the past decades and provide a basis for the colure correlations implemented in the RELAP-7 code. This document provides a summary on the closure correlations that are currently implemented in the RELAP-7 code. The closure correlations include sub-grid models that describe interactions between the fluids and the flow channel, and interactions between the two phases.

ASD Closure in Structural Heart Disease.

Science.gov (United States)

Wiktor, Dominik M; Carroll, John D

2018-04-17

While the safety and efficacy of percutaneous ASD closure has been established, new data have recently emerged regarding the negative impact of residual iatrogenic ASD (iASD) following left heart structural interventions. Additionally, new devices with potential advantages have recently been studied. We will review here the potential indications for closure of iASD along with new generation closure devices and potential late complications requiring long-term follow-up. With the expansion of left-heart structural interventions and large-bore transseptal access, there has been growing experience gained with management of residual iASD. Some recently published reports have implicated residual iASD after these procedures as a potential source of diminished clinical outcomes and mortality. Additionally, recent trials investigating new generation closure devices as well as expanding knowledge regarding late complications of percutaneous ASD closure have been published. While percutaneous ASD closure is no longer a novel approach to managing septal defects, there are several contemporary issues related to residual iASD following large-bore transseptal access and new generation devices which serve as an impetus for this review. Ongoing attention to potential late complications and decreasing their incidence with ongoing study is clearly needed.

Hanford Patrol Academy Demolition Sites Closure Plan

International Nuclear Information System (INIS)

1992-11-01

From 1975 to 1991 the Hanford Patrol Academy Demolition Sites (HPADS) were used for demolition events. These demolition events were a form of thermal treatment for spent or abandoned chemical waste. Because the HPADS will no longer be used for this thermal activity, the sites will be closed. Closure will be conducted pursuant to the requirements of the Washington State Department of Ecology (Ecology) Dangerous Waste Regulations, Washington Administrative Code (WAC) 173-303-610 and 40 CFR 270.1. Closure also will satisfy closure requirements of WAC 173-303-680 and for the thermal treatment closure requirements of 40 CFR 265.381. This closure plan presents a description of the HPADS, the history of the waste treated, and the approach that will be followed to close the HPADS. Because dangerous waste does not include the source, special nuclear, and by-product material components of mixed waste, radionuclides are not within the scope of WAC 173-303 or of this closure plan. The information on radionuclides is provided only for general knowledge where appropriate. Only dangerous constituents derived from HPADS operations will be addressed in this closure plan in accordance with WAC 173-303-610(2)(b)(i). The HPADS are actually two distinct soil closure areas within the Hanford Patrol Academy training area

A summary of methods for approximating salt creep and disposal room closure in numerical models of multiphase flow

Energy Technology Data Exchange (ETDEWEB)

Freeze, G.A.; Larson, K.W. [INTERA, Inc., Albuquerque, NM (United States); Davies, P.B. [Sandia National Labs., Albuquerque, NM (United States)

1995-10-01

Eight alternative methods for approximating salt creep and disposal room closure in a multiphase flow model of the Waste Isolation Pilot Plant (WIPP) were implemented and evaluated: Three fixed-room geometries three porosity functions and two fluid-phase-salt methods. The pressure-time-porosity line interpolation method is the method used in current WIPP Performance Assessment calculations. The room closure approximation methods were calibrated against a series of room closure simulations performed using a creep closure code, SANCHO. The fixed-room geometries did not incorporate a direct coupling between room void volume and room pressure. The two porosity function methods that utilized moles of gas as an independent parameter for closure coupling. The capillary backstress method was unable to accurately simulate conditions of re-closure of the room. Two methods were found to be accurate enough to approximate the effects of room closure; the boundary backstress method and pressure-time-porosity line interpolation. The boundary backstress method is a more reliable indicator of system behavior due to a theoretical basis for modeling salt deformation as a viscous process. It is a complex method and a detailed calibration process is required. The pressure lines method is thought to be less reliable because the results were skewed towards SANCHO results in simulations where the sequence of gas generation was significantly different from the SANCHO gas-generation rate histories used for closure calibration. This limitation in the pressure lines method is most pronounced at higher gas-generation rates and is relatively insignificant at lower gas-generation rates. Due to its relative simplicity, the pressure lines method is easier to implement in multiphase flow codes and simulations have a shorter execution time.

A summary of methods for approximating salt creep and disposal room closure in numerical models of multiphase flow

International Nuclear Information System (INIS)

Freeze, G.A.; Larson, K.W.; Davies, P.B.

1995-10-01

Eight alternative methods for approximating salt creep and disposal room closure in a multiphase flow model of the Waste Isolation Pilot Plant (WIPP) were implemented and evaluated: Three fixed-room geometries three porosity functions and two fluid-phase-salt methods. The pressure-time-porosity line interpolation method is the method used in current WIPP Performance Assessment calculations. The room closure approximation methods were calibrated against a series of room closure simulations performed using a creep closure code, SANCHO. The fixed-room geometries did not incorporate a direct coupling between room void volume and room pressure. The two porosity function methods that utilized moles of gas as an independent parameter for closure coupling. The capillary backstress method was unable to accurately simulate conditions of re-closure of the room. Two methods were found to be accurate enough to approximate the effects of room closure; the boundary backstress method and pressure-time-porosity line interpolation. The boundary backstress method is a more reliable indicator of system behavior due to a theoretical basis for modeling salt deformation as a viscous process. It is a complex method and a detailed calibration process is required. The pressure lines method is thought to be less reliable because the results were skewed towards SANCHO results in simulations where the sequence of gas generation was significantly different from the SANCHO gas-generation rate histories used for closure calibration. This limitation in the pressure lines method is most pronounced at higher gas-generation rates and is relatively insignificant at lower gas-generation rates. Due to its relative simplicity, the pressure lines method is easier to implement in multiphase flow codes and simulations have a shorter execution time

Cost effectiveness of risk-based closures at UST sites

International Nuclear Information System (INIS)

Scruton, K.M.; Baker, J.N.

1995-01-01

Risk-based closures have been achieved at Underground Storage Tank (UST) sites throughout the country for a major transportation company. The risk-based closures were cost-effective because a streamlined risk-based approach was used instead of the generic baseline risk assessment approach. USEPA has recently provided guidance encouraging the use of risk-based methodology for achieving closure at UST sites. The risk-based approach used in achieving the site closures involved an identification of potential human and ecological receptors and exposure pathways, and a comparison of maximum onsite chemical concentrations to applicable or relevant and appropriate requirements (ARARs). The ARARs used in the evaluation included Federal and/or State Maximum Contaminant Levels (MCLs) for groundwater and risk-based screening levels for soils. If the maximum concentrations were above the screening levels, a baseline risk assessment was recommended. In several instances, however, the risk-based approach resulted in a regulatory agency acceptance of a ''no further action'' alternative at UST sites which did not pose a significant threat to human health and the environment. The cost of the streamlined risk-based approach is approximately $3,500, while a baseline risk assessment for the same UST site could cost up to $10,000 or more. The use of the streamlined risk-based approach has proven to be successful for achieving a ''no further action'' outcome for the client at a reasonable cost

The numerical multiconfiguration self-consistent field approach for atoms

International Nuclear Information System (INIS)

Stiehler, Johannes

1995-12-01

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

Flow simulation in piping system dead legs using second moment, closure and k-epsilon model

International Nuclear Information System (INIS)

Deutsch, E.; Mechitoua, N.; Mattei, J.D.

1996-01-01

This paper deals with an industrial application of second moment closure turbulence model in in numerical simulation of 3D turbulent flows in piping system dead legs. Calculations performed with the 3D ESTET code are presented which contrast the performance of k-epsilon eddy viscosity model and second moment closure turbulence models. Coarse (100 000), medium (400 000) and fine (1 500 000) meshes were used. The second moment closure performs significantly better than eddy viscosity model and predicts with a good agreement the vortex penetration in dead legs provided to use sufficiently refined meshes. The results point out the necessity to be able to perform calculations using fine mesh before introducing refined physical models such as second moment closure turbulence model in a numerical code. This study illustrates the ability of second moment closure turbulence model to simulate 3D turbulent industrial flows. Reynolds stress model computation does not require special care, the calculation is carried on as simply as the k-ξ one. The CPU time needed is less that twice the CPU time needed using k-ξ model. (authors)

Strategic Planning for Hot Cell Closure

International Nuclear Information System (INIS)

LANGSTAFF, D.C.

2001-01-01

The United States Department of Energy (DOE) and its contractor were remediating a large hot cell complex to mitigate the radiological hazard. A Resource Conservation and Recovery Act (RCRA) closure unit was determined to be located within the complex. The regulator established a challenge to develop an acceptable closure plan on a short schedule (four months). The scope of the plan was to remove all excess equipment and mixed waste from the closure unit, establish the requirements of the legally binding Closure Plan and develop an acceptable schedule. The complex has several highly radioactive tanks, tank vaults, piping, and large hot cells containing complex chemical processing equipment. Driven by a strong need to develop an effective strategy to meet cleanup commitments, three principles were followed to develop an acceptable plan: (1) Use a team approach, (2) Establish a buffer zone to support closure, and (3) Use good practice when planning the work sequence. The team was composed of DOE, contractor, and Washington State Department of Ecology (Regulator) staff. The team approach utilized member expertise and fostered member involvement and communication. The buffer zone established an area between the unregulated parts of the building and the areas that were allegedly not in compliance with environmental standards. Introduction of the buffer zone provided simplicity, clarity, and flexibility into the process. Using good practice means using the DOE Integrated Safety Management Core Functions for planning and implementing work safely. Paying adequate attention to detail when the situation required contributed to the process credibility and a successful plan

Numerical analysis of turbulent flow and heat transfer in a square sectioned U-bend duct by elliptic-blending second moment closure

International Nuclear Information System (INIS)

Shin, Jong Keun; Choi, Young Don; An, Jeong Soo

2007-01-01

A second moment turbulence closure using the elliptic-blending equation is introduced to analyze the turbulence and heat transfer in a square sectioned U-bend duct flow. The turbulent heat flux model based on the elliptic concept satisfies the near-wall balance between viscous diffusion, viscous dissipation and temperature-pressure gradient correlation, and also has the characteristics of approaching its respective conventional high Reynolds number model far away from the wall. Also, the traditional GGDH heat flux model is compared with the present elliptic concept-based heat flux model. The turbulent heat flux models are closely linked to the elliptic blending second moment closure which is used for the prediction of Reynolds stresses. The predicted results show their reasonable agreement with experimental data for a square sectioned U-bend duct flow field adopted in the present study

Limited utility of preoperative studies in preparation for colostomy closure.

Science.gov (United States)

Pokorny, R M; Heniford, T; Allen, J W; Tuckson, W B; Galandiuk, S

1999-04-01

Numerous diagnostic and therapeutic practices are used in an attempt to reduce the morbidity of colostomy closures. Our principal aim was to evaluate the role of preoperative studies, specifically barium enemas and endoscopic examinations, performed before colostomy closures. Additionally, we wished to identify other practices involved in the perioperative management of patients undergoing colostomy closure that influenced morbidity. The records of 100 consecutive patients who underwent elective colostomy closure at University of Louisville Hospital between January 1989 and July 1995 were reviewed. Wound infection was the most common complication (12%). Various bowel preparations were equivalent in efficacy and did not influence the complication rate. Intermittent wound irrigation with antibiotics for 3 days postoperatively, via subcutaneous drains, was associated with a low incidence of incision infection. Preoperative barium enema or sigmoidoscopy were often performed but rarely useful. Performing these examinations merely increased hospital cost without a corresponding decline in morbidity.

Guidance for closure of existing DOE LLW disposal sites

International Nuclear Information System (INIS)

Blanchfield, L.

1987-01-01

During FY 1986, a closure guidance document was developed. The purpose of this document is to provide guidance in support of DOE Order 5820.2 to site operating contractors for the stabilization and closure of existing low-level waste (LLW) shallow land disposal sites at US Department of Energy (DOE) facilities. Guidance is provided to aid operators in placing existing LLW sites in a closed conditions, i.e., a condition in which a nonoperational site meets postclosure performance requirements and can be shown, within a high degree of confidence, to perform as anticipated in the future, under the most cost-effective maintenance approach. Guidance is based on the philosophy that closure should be planned and performed using a systems approach. Plans for FY 1987 call for revision of the document to incorporate more information on closure of LLW sites also containing radioactive mixed waste and/or transuranic waste. 4 references, 3 figures, 2 tables

Stochastic particle acceleration and statistical closures

International Nuclear Information System (INIS)

Dimits, A.M.; Krommes, J.A.

1985-10-01

In a recent paper, Maasjost and Elsasser (ME) concluded, from the results of numerical experiments and heuristic arguments, that the Bourret and the direct-interaction approximation (DIA) are ''of no use in connection with the stochastic acceleration problem'' because (1) their predictions were equivalent to that of the simpler Fokker-Planck (FP) theory, and (2) either all or none of the closures were in good agreement with the data. Here some analytically tractable cases are studied and used to test the accuracy of these closures. The cause of the discrepancy (2) is found to be the highly non-Gaussian nature of the force used by ME, a point not stressed by them. For the case where the force is a position-independent Ornstein-Uhlenbeck (i.e., Gaussian) process, an effective Kubo number K can be defined. For K << 1 an FP description is adequate, and conclusion (1) of ME follows; however, for K greater than or equal to 1 the DIA behaves much better qualitatively than the other two closures. For the non-Gaussian stochastic force used by ME, all common approximations fail, in agreement with (2)

Scale separation closure and Alfven wave turbulence

International Nuclear Information System (INIS)

Chen, C.Y.; Mahajan, S.M.

1985-04-01

Based on the concept of scale separation between coherent response function and incoherent source for renormalized turbulence theories, a closure scheme is proposed. A model problem dealing with shear-Alfven wave turbulence is numerically solved; the solution explicitly shows expected turbulence features such as frequency shift from linear modes, band-broadening, and a power law dependence for the turbulence spectrum

Procedures and techniques for closure of near surface disposal facilities for radioactive waste

International Nuclear Information System (INIS)

2001-12-01

The overall objective of this report is to provide Member States with guidance on planning and implementation of closure of near surface disposal facilities for low and intermediate level radioactive waste. The specific objectives are to review closure concepts, requirements, and components of closure systems; to discuss issues and approaches to closure, including regulatory, economic, and technical aspects; and to present major examples of closure techniques used and/or considered by Member States. Some examples of closure experience from Member States are presented in the Appendix and were indexed separately

Closure requirements

International Nuclear Information System (INIS)

Hutchinson, I.P.G.; Ellison, R.D.

1992-01-01

Closure of a waste management unit can be either permanent or temporary. Permanent closure may be due to: economic factors which make it uneconomical to mine the remaining minerals; depletion of mineral resources; physical site constraints that preclude further mining and beneficiation; environmental, regulatory or other requirements that make it uneconomical to continue to develop the resources. Temporary closure can occur for a period of several months to several years, and may be caused by factors such as: periods of high rainfall or snowfall which prevent mining and waste disposal; economic circumstances which temporarily make it uneconomical to mine the target mineral; labor problems requiring a cessation of operations for a period of time; construction activities that are required to upgrade project components such as the process facilities and waste management units; and mine or process plant failures that require extensive repairs. Permanent closure of a mine waste management unit involves the provision of durable surface containment features to protect the waters of the State in the long-term. Temporary closure may involve activities that range from ongoing maintenance of the existing facilities to the installation of several permanent closure features in order to reduce ongoing maintenance. This paper deals with the permanent closure features

Hamiltonian closures in fluid models for plasmas

Science.gov (United States)

Tassi, Emanuele

2017-11-01

This article reviews recent activity on the Hamiltonian formulation of fluid models for plasmas in the non-dissipative limit, with emphasis on the relations between the fluid closures adopted for the different models and the Hamiltonian structures. The review focuses on results obtained during the last decade, but a few classical results are also described, in order to illustrate connections with the most recent developments. With the hope of making the review accessible not only to specialists in the field, an introduction to the mathematical tools applied in the Hamiltonian formalism for continuum models is provided. Subsequently, we review the Hamiltonian formulation of models based on the magnetohydrodynamics description, including those based on the adiabatic and double adiabatic closure. It is shown how Dirac's theory of constrained Hamiltonian systems can be applied to impose the incompressibility closure on a magnetohydrodynamic model and how an extended version of barotropic magnetohydrodynamics, accounting for two-fluid effects, is amenable to a Hamiltonian formulation. Hamiltonian reduced fluid models, valid in the presence of a strong magnetic field, are also reviewed. In particular, reduced magnetohydrodynamics and models assuming cold ions and different closures for the electron fluid are discussed. Hamiltonian models relaxing the cold-ion assumption are then introduced. These include models where finite Larmor radius effects are added by means of the gyromap technique, and gyrofluid models. Numerical simulations of Hamiltonian reduced fluid models investigating the phenomenon of magnetic reconnection are illustrated. The last part of the review concerns recent results based on the derivation of closures preserving a Hamiltonian structure, based on the Hamiltonian structure of parent kinetic models. Identification of such closures for fluid models derived from kinetic systems based on the Vlasov and drift-kinetic equations are presented, and

Performance Assessment for Pump-and-Treat Closure or Transition

Energy Technology Data Exchange (ETDEWEB)

Truex, Michael J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Johnson, Christian D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Becker, Dave J. [U.S. Army Corps of Engineers Environmental and Munitions Center of Expertise, Huntsville, AL (United States); Lee, Michelle H. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Nimmons, Michael J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2015-09-29

A structured performance assessment approach is useful to evaluate pump-and-treat (P&T) groundwater remediation, which has been applied at numerous sites. Consistent with the U.S. Environmental Protection Agency’s Groundwater Road Map, performance assessment during remedy implementation may be needed, and should consider remedy optimization, transition to alternative remedies, or remedy closure. In addition, a recent National Research Council study examined groundwater remediation at complex contaminated sites and concluded that it may be beneficial to evaluate remedy performance and the potential need for transition to alternative approaches at these sites. The intent of this document is to provide a structured approach for assessing P&T performance to support a decision to optimize, transition, or close a P&T remedy. The process presented in this document for gathering information and performing evaluations to support P&T remedy decisions includes use of decision elements to distinguish between potential outcomes of a remedy decision. Case studies are used to augment descriptions of decision elements and to illustrate each type of outcome identified in the performance assessment approach. The document provides references to resources for tools and other guidance relevant to conducting the P&T assessment.

Novi Han Radioactive Waste Repository post-closure safety assessment, ver.2

International Nuclear Information System (INIS)

Mateeva, M.

2003-01-01

The methodology for the post-closure safety assessment is presented. The assessment context includes regulatory framework (protection principles); scope and time frame; radiological and technical requirements; modeling etc. The description of the Novi Han disposal system contains site location. meteorological, hydrological and seismological characteristics; waste and repository description and human activities characteristics. The next step in the methodology is scenario development and justification. The systematic generation os exposure scenarios is considered as central to the post-closure safety assessment. The most important requirements for the systematic scenario generation approach are: transparency, comprehensiveness (all possible FEPs influencing the the disposal system and the radionuclide release should be considered); relevant future evolutions; identification of critical issues and investigation of the robustness of the system. For the source-pathway-receptor analysis the Process System is divided into near-field, geosphere/atmosphere and biosphere, describing the key facets controlling the potential radionuclide migration to the environment. The schematic division of the Novi Han near-field Process System into lower-level conceptual features is presented and discussed. As a result of the examinations of the FEPs three classes of scenarios are identified for the Novi Han post-closure safety assessment: Environmental evolution scenarios (geological change and climate change); future human action scenarios (human intrusion and archaeological action); Scenarios with very low probability (terrorism, crashes, explosions). The safety assessment iteration leads to identification of a modern scenario generation approach, assessment of key radionuclide releases, geological and hydrological evaluation, identification of the key parameters from sensitivity analysis etc. Examples of conceptual models are given. For the mathematical modeling the AMBER code is used

Evaluation of Two Energy Balance Closure Parametrizations

Science.gov (United States)

Eder, Fabian; De Roo, Frederik; Kohnert, Katrin; Desjardins, Raymond L.; Schmid, Hans Peter; Mauder, Matthias

2014-05-01

A general lack of energy balance closure indicates that tower-based eddy-covariance (EC) measurements underestimate turbulent heat fluxes, which calls for robust correction schemes. Two parametrization approaches that can be found in the literature were tested using data from the Canadian Twin Otter research aircraft and from tower-based measurements of the German Terrestrial Environmental Observatories (TERENO) programme. Our analysis shows that the approach of Huang et al. (Boundary-Layer Meteorol 127:273-292, 2008), based on large-eddy simulation, is not applicable to typical near-surface flux measurements because it was developed for heights above the surface layer and over homogeneous terrain. The biggest shortcoming of this parametrization is that the grid resolution of the model was too coarse so that the surface layer, where EC measurements are usually made, is not properly resolved. The empirical approach of Panin and Bernhofer (Izvestiya Atmos Oceanic Phys 44:701-716, 2008) considers landscape-level roughness heterogeneities that induce secondary circulations and at least gives a qualitative estimate of the energy balance closure. However, it does not consider any feature of landscape-scale heterogeneity other than surface roughness, such as surface temperature, surface moisture or topography. The failures of both approaches might indicate that the influence of mesoscale structures is not a sufficient explanation for the energy balance closure problem. However, our analysis of different wind-direction sectors shows that the upwind landscape-scale heterogeneity indeed influences the energy balance closure determined from tower flux data. We also analyzed the aircraft measurements with respect to the partitioning of the "missing energy" between sensible and latent heat fluxes and we could confirm the assumption of scalar similarity only for Bowen ratios 1.

Correção endovascular de persistência do conduto arterioso em paciente adulto Endovascular approach for persistent ductus arteriosus closure in adult patient

Directory of Open Access Journals (Sweden)

José Carlos Dorsa Vieira Pontes

2010-03-01

Full Text Available O tratamento da Persistência do Canal Arterial (PCA, em adultos, ainda é controverso. A utilização de próteses auto-expansíveis tem-se mostrado como uma alternativa eficaz ao tratamento cirúrgico. Apresentamos um caso de uma paciente de 45 anos submetida ao tratamento endovascular com o uso de stent auto-expansível.The treatment for closure of persistent ductus arteriosus (PDA in adults still controversial. The endovascular approach has been shown as an effective alternative to surgical treatment. We report a case of 45 years old pacient submitted to endovascular approach for PDA closure.

Improving environmental performance through mine closure planning

International Nuclear Information System (INIS)

McKee, W.; McKenna, G.

1998-01-01

Syncrude has been investigating landscape redevelopment concepts since 1995 after a two-year tailings technology selection study resulted in a major shift in their long-term tailings disposal strategy. The change from fluid disposal to solid disposal of tailings leads to a different landscape, incorporating a new water material type, new landforms and a new schedule of reclamation activity. A multidisciplinary approach was needed to assess, design and develop the final landscape. Planning approach in progress at Syncrude Canada was described, and the basic concepts and tools of closure planning discovered to date were outlined. The economic impacts of closure planning on mining and tailings operations in general, were discussed. 14 refs

Stable Numerical Approach for Fractional Delay Differential Equations

Science.gov (United States)

Singh, Harendra; Pandey, Rajesh K.; Baleanu, D.

2017-12-01

In this paper, we present a new stable numerical approach based on the operational matrix of integration of Jacobi polynomials for solving fractional delay differential equations (FDDEs). The operational matrix approach converts the FDDE into a system of linear equations, and hence the numerical solution is obtained by solving the linear system. The error analysis of the proposed method is also established. Further, a comparative study of the approximate solutions is provided for the test examples of the FDDE by varying the values of the parameters in the Jacobi polynomials. As in special case, the Jacobi polynomials reduce to the well-known polynomials such as (1) Legendre polynomial, (2) Chebyshev polynomial of second kind, (3) Chebyshev polynomial of third and (4) Chebyshev polynomial of fourth kind respectively. Maximum absolute error and root mean square error are calculated for the illustrated examples and presented in form of tables for the comparison purpose. Numerical stability of the presented method with respect to all four kind of polynomials are discussed. Further, the obtained numerical results are compared with some known methods from the literature and it is observed that obtained results from the proposed method is better than these methods.

Multilevel Monte Carlo Approaches for Numerical Homogenization

KAUST Repository

Efendiev, Yalchin R.

2015-10-01

In this article, we study the application of multilevel Monte Carlo (MLMC) approaches to numerical random homogenization. Our objective is to compute the expectation of some functionals of the homogenized coefficients, or of the homogenized solutions. This is accomplished within MLMC by considering different sizes of representative volumes (RVEs). Many inexpensive computations with the smallest RVE size are combined with fewer expensive computations performed on larger RVEs. Likewise, when it comes to homogenized solutions, different levels of coarse-grid meshes are used to solve the homogenized equation. We show that, by carefully selecting the number of realizations at each level, we can achieve a speed-up in the computations in comparison to a standard Monte Carlo method. Numerical results are presented for both one-dimensional and two-dimensional test-cases that illustrate the efficiency of the approach.

Transcatheter closure of patent ductus arteriosus: past, present and future.

Science.gov (United States)

Baruteau, Alban-Elouen; Hascoët, Sébastien; Baruteau, Julien; Boudjemline, Younes; Lambert, Virginie; Angel, Claude-Yves; Belli, Emre; Petit, Jérôme; Pass, Robert

2014-02-01

This review aims to describe the past history, present techniques and future directions in transcatheter treatment of patent ductus arteriosus (PDA). Transcatheter PDA closure is the standard of care in most cases and PDA closure is indicated in any patient with signs of left ventricular volume overload due to a ductus. In cases of left-to-right PDA with severe pulmonary arterial hypertension, closure may be performed under specific conditions. The management of clinically silent or very tiny PDAs remains highly controversial. Techniques have evolved and the transcatheter approach to PDA closure is now feasible and safe with current devices. Coils and the Amplatzer Duct Occluder are used most frequently for PDA closure worldwide, with a high occlusion rate and few complications. Transcatheter PDA closure in preterm or low-bodyweight infants remains a highly challenging procedure and further device and catheter design development is indicated before transcatheter closure is the treatment of choice in this delicate patient population. The evolution of transcatheter PDA closure from just 40 years ago with 18F sheaths to device delivery via a 3F sheath is remarkable and it is anticipated that further improvements will result in better safety and efficacy of transcatheter PDA closure techniques. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Multivariate moment closure techniques for stochastic kinetic models

International Nuclear Information System (INIS)

Lakatos, Eszter; Ale, Angelique; Kirk, Paul D. W.; Stumpf, Michael P. H.

2015-01-01

Stochastic effects dominate many chemical and biochemical processes. Their analysis, however, can be computationally prohibitively expensive and a range of approximation schemes have been proposed to lighten the computational burden. These, notably the increasingly popular linear noise approximation and the more general moment expansion methods, perform well for many dynamical regimes, especially linear systems. At higher levels of nonlinearity, it comes to an interplay between the nonlinearities and the stochastic dynamics, which is much harder to capture correctly by such approximations to the true stochastic processes. Moment-closure approaches promise to address this problem by capturing higher-order terms of the temporally evolving probability distribution. Here, we develop a set of multivariate moment-closures that allows us to describe the stochastic dynamics of nonlinear systems. Multivariate closure captures the way that correlations between different molecular species, induced by the reaction dynamics, interact with stochastic effects. We use multivariate Gaussian, gamma, and lognormal closure and illustrate their use in the context of two models that have proved challenging to the previous attempts at approximating stochastic dynamics: oscillations in p53 and Hes1. In addition, we consider a larger system, Erk-mediated mitogen-activated protein kinases signalling, where conventional stochastic simulation approaches incur unacceptably high computational costs

Multivariate moment closure techniques for stochastic kinetic models

Energy Technology Data Exchange (ETDEWEB)

Lakatos, Eszter, E-mail: e.lakatos13@imperial.ac.uk; Ale, Angelique; Kirk, Paul D. W.; Stumpf, Michael P. H., E-mail: m.stumpf@imperial.ac.uk [Department of Life Sciences, Centre for Integrative Systems Biology and Bioinformatics, Imperial College London, London SW7 2AZ (United Kingdom)

2015-09-07

Stochastic effects dominate many chemical and biochemical processes. Their analysis, however, can be computationally prohibitively expensive and a range of approximation schemes have been proposed to lighten the computational burden. These, notably the increasingly popular linear noise approximation and the more general moment expansion methods, perform well for many dynamical regimes, especially linear systems. At higher levels of nonlinearity, it comes to an interplay between the nonlinearities and the stochastic dynamics, which is much harder to capture correctly by such approximations to the true stochastic processes. Moment-closure approaches promise to address this problem by capturing higher-order terms of the temporally evolving probability distribution. Here, we develop a set of multivariate moment-closures that allows us to describe the stochastic dynamics of nonlinear systems. Multivariate closure captures the way that correlations between different molecular species, induced by the reaction dynamics, interact with stochastic effects. We use multivariate Gaussian, gamma, and lognormal closure and illustrate their use in the context of two models that have proved challenging to the previous attempts at approximating stochastic dynamics: oscillations in p53 and Hes1. In addition, we consider a larger system, Erk-mediated mitogen-activated protein kinases signalling, where conventional stochastic simulation approaches incur unacceptably high computational costs.

A numerical study of non-linear crack tip parameters

Directory of Open Access Journals (Sweden)

F.V. Antunes

2015-07-01

Full Text Available Crack closure concept has been widely used to explain different issues of fatigue crack propagation. However, different authors have questioned the relevance of crack closure and have proposed alternative concepts. The main objective here is to check the effectiveness of crack closure concept by linking the contact of crack flanks with non-linear crack tip parameters. Accordingly, 3D-FE numerical models with and without contact were developed for a wide range of loading scenarios and the crack tip parameters usually linked to fatigue crack growth, namely range of cyclic plastic strain, crack tip opening displacement, size of reversed plastic zone and total plastic dissipation per cycle, were investigated. It was demonstrated that: i LEFM concepts are applicable to the problem under study; ii the crack closure phenomenon has a great influence on crack tip parameters decreasing their values; iii the Keff concept is able to explain the variations of crack tip parameters produced by the contact of crack flanks; iv the analysis of remote compliance is the best numerical parameter to quantify the crack opening level; v without contact there is no effect of stress ratio on crack tip parameters. Therefore it is proved that the crack closure concept is valid.

Closure Plan for Active Low Level Burial Grounds

Energy Technology Data Exchange (ETDEWEB)

SKELLY, W.A.

2000-11-16

This plan has been prepared in response to direction from the U.S. Department of Energy. The purpose of the plan is to define approaches that will be implemented to ensure protection of the public and the environment when active Low-Level Burial Grounds (LLBGs) at the Hanford Site are closed. Performance assessments for active burial grounds in the 200 East and West 200 Areas provide current estimates of potential environmental contamination and doses to the ''maximum exposed individual'' from burial ground operation and closure and compare dose estimates to performance objective dose limits for the facilities. This is an Operational Closure Plan. The intent of the guidance in DOE Order 435.1 is that this plan will be a living document, like the facility performance assessments, and will be revised periodically through the operational life of the LLBGs to reflect updated information on waste inventory. management practices, facility transition planning, schedule dates, assessments of post-closure performance, and environmental consequences. Out year dates identified in this plan are tentative. A Final Closure Plan will be prepared in the future when the timing and extent of closure-related activities for LLBGs can be established with greater certainty. After current operations at the LLBGs are concluded, this plan proposes transitioning of these facilities to the Environmental Restoration Program. This action will enable the Environmental Restoration Program to design and implement consistent and coordinated final remedial actions for active and inactive LLBGs. Active and inactive burial grounds in the 200 West and 200 East Areas are commingled. This plan describes approaches that will be implemented during Interim Closure, Final Closure, and Institutional Control Periods to prepare LLBGs for surface barriers, and the construction of barriers, as well as the scope of inspection, monitoring and maintenance practices that will be performed during

Effectiveness of Closure of Public Places with Time Delay in Disease Control

Directory of Open Access Journals (Sweden)

Wang Zhenggang

2008-06-01

Full Text Available A theoretical basis for the evaluation of the effciency of quarantine measure is developed in a SIR model with time delay. In this model, the effectiveness of the closure of public places such as schools in disease control, modeled as a high degree node in a social network, is evaluated by considering the effect of the time delay in the identification of the infected. In the context of the SIR model, the relation between the number of infectious individuals who are identified with time delay and then quarantined and those who are not identified and continue spreading the virus are investigated numerically. The social network for the simulation is modeled by a scale free network. Closure measures are applied to those infected nodes with high degrees. The effectiveness of the measure can be controlled by the present value of the critical degree KC: only those nodes with degree higher than KC will be quarantined. The cost CQ incurred for the closure measure is assumed to be proportional to the total links rendered inactive as a result of the measure, and generally decreases with KC, while the medical cost CQ incurred for virus spreading increases with KC. The total social cost (CM + CQ will have a minimum at a critical KC, which depends on the ratio of medical cost coeffcient αM and closure cost coeffcient αQ. Our simulation results demonstrate a mathematical procedure to evaluate the effciency of quarantine measure. Although the numerical work is based on a scale free network, the procedure can be readily generalized and applied to a more realistic social network to determine the proper closure measure in future epidemics.

Comparing approaches to screening for angle closure in older Chinese adults

Science.gov (United States)

Andrews, J; Chang, D S; Jiang, Y; He, M; Foster, P J; Munoz, B; Kashiwagi, K; Friedman, D S

2012-01-01

Aims Primary angle-closure glaucoma is expected to account for nearly 50% of bilateral glaucoma blindness by 2020. This study was conducted to assess the performance of the scanning peripheral anterior chamber depth analyzer (SPAC) and limbal anterior chamber depth (LACD) as screening methods for angle closure. Methods This study assessed two clinical populations to compare SPAC, LACD, and gonioscopy: the Zhongshan Angle-closure Prevention Trial, from which 370 patients were eligible as closed-angle participants and the Liwan Eye Study, from which 72 patients were selected as open-angle controls. Eligible participants were assessed by SPAC, LACD, and gonioscopy. Results Angle status was defined by gonioscopy. Area under the receiver operating characteristic curve (AUROC) for SPAC was 0.92 (0.89–0.95) whereas AUROC for LACD was 0.94 (0.92–0.97). Using conventional cutoff points, sensitivity/specificity was 93.0%/70.8% for SPAC and 94.1%/87.5% for LACD. Sequential testing using both SPAC and LACD increased the specificity to 94.4% and decreased the sensitivity to 87.0%. Conclusion SPAC has significantly lower specificity than LACD measurement using conventional cutoffs but interpretation of the findings can be performed by modestly trained personnel. PMID:21997356

Data-driven non-Markovian closure models

Science.gov (United States)

Kondrashov, Dmitri; Chekroun, Mickaël D.; Ghil, Michael

2015-03-01

This paper has two interrelated foci: (i) obtaining stable and efficient data-driven closure models by using a multivariate time series of partial observations from a large-dimensional system; and (ii) comparing these closure models with the optimal closures predicted by the Mori-Zwanzig (MZ) formalism of statistical physics. Multilayer stochastic models (MSMs) are introduced as both a generalization and a time-continuous limit of existing multilevel, regression-based approaches to closure in a data-driven setting; these approaches include empirical model reduction (EMR), as well as more recent multi-layer modeling. It is shown that the multilayer structure of MSMs can provide a natural Markov approximation to the generalized Langevin equation (GLE) of the MZ formalism. A simple correlation-based stopping criterion for an EMR-MSM model is derived to assess how well it approximates the GLE solution. Sufficient conditions are derived on the structure of the nonlinear cross-interactions between the constitutive layers of a given MSM to guarantee the existence of a global random attractor. This existence ensures that no blow-up can occur for a broad class of MSM applications, a class that includes non-polynomial predictors and nonlinearities that do not necessarily preserve quadratic energy invariants. The EMR-MSM methodology is first applied to a conceptual, nonlinear, stochastic climate model of coupled slow and fast variables, in which only slow variables are observed. It is shown that the resulting closure model with energy-conserving nonlinearities efficiently captures the main statistical features of the slow variables, even when there is no formal scale separation and the fast variables are quite energetic. Second, an MSM is shown to successfully reproduce the statistics of a partially observed, generalized Lotka-Volterra model of population dynamics in its chaotic regime. The challenges here include the rarity of strange attractors in the model's parameter

Overview of the closure approach for the Hanford Site single-shell tank farm

International Nuclear Information System (INIS)

Smith, E.H.

1991-09-01

The disposal of chemical and radioactive waste stored within the single-shell tanks (SST) represents one of the most significant waste management problems at the Hanford Site. A comprehensive program has been established to obtain analytical data regarding the chemical and radiological constituents within these tanks. This information will be used to support the development of a supplemental environmental impact statement (SEIS) and ultimately to aid in the selection of a final disposal option. This paper discusses some of the technical options and major regulatory issues associated with SST waste retrieval and in situ waste treatment and disposal. Certain closure options and treatment technologies will require further development before they can be implemented or accepted as being useful. In addition, continued negotiations with the regulatory authorities will be required to determine the preferred closure option and the regulatory pathway to accommodate such closure

Simulating school closure policies for cost effective pandemic decision making

Directory of Open Access Journals (Sweden)

Araz Ozgur M

2012-06-01

Full Text Available Abstract Background Around the globe, school closures were used sporadically to mitigate the 2009 H1N1 influenza pandemic. However, such closures can detrimentally impact economic and social life. Methods Here, we couple a decision analytic approach with a mathematical model of influenza transmission to estimate the impact of school closures in terms of epidemiological and cost effectiveness. Our method assumes that the transmissibility and the severity of the disease are uncertain, and evaluates several closure and reopening strategies that cover a range of thresholds in school-aged prevalence (SAP and closure durations. Results Assuming a willingness to pay per quality adjusted life-year (QALY threshold equal to the US per capita GDP ($46,000, we found that the cost effectiveness of these strategies is highly dependent on the severity and on a willingness to pay per QALY. For severe pandemics, the preferred strategy couples the earliest closure trigger (0.5% SAP with the longest duration closure (24 weeks considered. For milder pandemics, the preferred strategies also involve the earliest closure trigger, but are shorter duration (12 weeks for low transmission rates and variable length for high transmission rates. Conclusions These findings highlight the importance of obtaining early estimates of pandemic severity and provide guidance to public health decision-makers for effectively tailoring school closures strategies in response to a newly emergent influenza pandemic.

Road Closures

Data.gov (United States)

Montgomery County of Maryland — This is an up to date map of current road closures in Montgomery County.This dataset is updated every few minutes from the Department of Transportation road closure...

Verification of Heat and Mass Transfer Closures in Industrial Scale Packed Bed Reactor Simulations

Directory of Open Access Journals (Sweden)

Arpit Singhal

2018-03-01

Full Text Available Particle-resolved direct numerical simulation (PR-DNS is known to provide an accurate detailed insight into the local flow phenomena in static particle arrays. Most PR-DNS studies in literature do not account for reactions taking place inside the porous particles. In this study, PR-DNS is performed for catalytic reactions inside the particles using the multifluid approach where all heat and mass transfer phenomena are directly resolved both inside and outside the particles. These simulation results are then used to verify existing 1D model closures from literature over a number of different reaction parameters including different reaction orders, multiple reactions and reactants, interacting reactions, and reactions involving gas volume generation/consumption inside the particle. Results clearly showed that several modifications to existing 1D model closures are required to reproduce PR-DNS results. The resulting enhanced 1D model was then used to accurately simulate steam methane reforming, which includes all of the aforementioned reaction complexities. The effect of multiple reactants was found to be the most influential in this case.

Comparison of different moment-closure approximations for stochastic chemical kinetics

Energy Technology Data Exchange (ETDEWEB)

Schnoerr, David [School of Biological Sciences, University of Edinburgh, Edinburgh (United Kingdom); School of Informatics, University of Edinburgh, Edinburgh (United Kingdom); Sanguinetti, Guido [School of Informatics, University of Edinburgh, Edinburgh (United Kingdom); Grima, Ramon [School of Biological Sciences, University of Edinburgh, Edinburgh (United Kingdom)

2015-11-14

In recent years, moment-closure approximations (MAs) of the chemical master equation have become a popular method for the study of stochastic effects in chemical reaction systems. Several different MA methods have been proposed and applied in the literature, but it remains unclear how they perform with respect to each other. In this paper, we study the normal, Poisson, log-normal, and central-moment-neglect MAs by applying them to understand the stochastic properties of chemical systems whose deterministic rate equations show the properties of bistability, ultrasensitivity, and oscillatory behaviour. Our results suggest that the normal MA is favourable over the other studied MAs. In particular, we found that (i) the size of the region of parameter space where a closure gives physically meaningful results, e.g., positive mean and variance, is considerably larger for the normal closure than for the other three closures, (ii) the accuracy of the predictions of the four closures (relative to simulations using the stochastic simulation algorithm) is comparable in those regions of parameter space where all closures give physically meaningful results, and (iii) the Poisson and log-normal MAs are not uniquely defined for systems involving conservation laws in molecule numbers. We also describe the new software package MOCA which enables the automated numerical analysis of various MA methods in a graphical user interface and which was used to perform the comparative analysis presented in this paper. MOCA allows the user to develop novel closure methods and can treat polynomial, non-polynomial, as well as time-dependent propensity functions, thus being applicable to virtually any chemical reaction system.

Stress analysis of closure bolts for shipping casks

International Nuclear Information System (INIS)

Mok, G.C.; Fischer, L.E.; Hsu, S.T.

1993-01-01

This report specifies the requirements and criteria for stress analysis of closure bolts for shipping casks containing nuclear spent fuels or high level radioactive materials. The specification is based on existing information conceming the structural behavior, analysis, and design of bolted joints. The approach taken was to extend the ASME Boiler and Pressure Vessel Code requirements and criteria for bolting analysis of nuclear piping and pressure vessels to include the appropriate design and load characteristics of the shipping cask. The characteristics considered are large, flat, closure lids with metal-to-metal contact within the bolted joint; significant temperature and impact loads; and possible prying and bending effects. Specific formulas and procedures developed apply to the bolt stress analysis of a circular, flat, bolted closure. The report also includes critical load cases and desirable design practices for the bolted closure, an in-depth review of the structural behavior of bolted joints, and a comprehensive bibliography of current information on bolted joints

Towards a collisionless fluid closure in plasma turbulence

Energy Technology Data Exchange (ETDEWEB)

Dif Pradalier, G

2005-07-01

In this work 2 generic possible descriptions of a plasma have been compared namely the kinetic and the fluid approaches. The latter focuses on the successive moments (n, u, p, q,...) of the distribution function, whereas the former describes the time-evolution in phase space of this distribution function, both being based on the Vlasov equation. The fluid description is attractive for the Vlasov equation is tractable with great difficulties. Nevertheless it rests on a major difficulty: as the set of fluid equations constitute an infinite hierarchy, a closure equation must be chosen. The first chapter details physical characteristics of a fundamental kinetic interaction mechanism between waves and particles. In chapter 2 we propose a fluid closure that allows analytic comparison with a linear fully kinetic result, near an homogeneous, electrostatic, Maxwellian equilibrium. This approach consists in adjusting chosen parameters in order to minimize the discrepancies between fluid and kinetic linear response functions. In chapter 3 we present a general frame for a fluid closure in a magnetized plasma. This is attempted in a linear, simplified model with low dimensionality.

Interferometric Imaging Directly with Closure Phases and Closure Amplitudes

Science.gov (United States)

Chael, Andrew A.; Johnson, Michael D.; Bouman, Katherine L.; Blackburn, Lindy L.; Akiyama, Kazunori; Narayan, Ramesh

2018-04-01

Interferometric imaging now achieves angular resolutions as fine as ∼10 μas, probing scales that are inaccessible to single telescopes. Traditional synthesis imaging methods require calibrated visibilities; however, interferometric calibration is challenging, especially at high frequencies. Nevertheless, most studies present only a single image of their data after a process of “self-calibration,” an iterative procedure where the initial image and calibration assumptions can significantly influence the final image. We present a method for efficient interferometric imaging directly using only closure amplitudes and closure phases, which are immune to station-based calibration errors. Closure-only imaging provides results that are as noncommittal as possible and allows for reconstructing an image independently from separate amplitude and phase self-calibration. While closure-only imaging eliminates some image information (e.g., the total image flux density and the image centroid), this information can be recovered through a small number of additional constraints. We demonstrate that closure-only imaging can produce high-fidelity results, even for sparse arrays such as the Event Horizon Telescope, and that the resulting images are independent of the level of systematic amplitude error. We apply closure imaging to VLBA and ALMA data and show that it is capable of matching or exceeding the performance of traditional self-calibration and CLEAN for these data sets.

Numerical analysis for prediction of fatigue crack opening level

International Nuclear Information System (INIS)

Choi, Hyeon Chang

2004-01-01

Finite Element Analysis (FEA) is the most popular numerical method to simulate plasticity-induced fatigue crack closure and can predict fatigue crack closure behavior. Finite element analysis under plane stress state using 4-node isoparametric elements is performed to investigate the detailed closure behavior of fatigue cracks and the numerical results are compared with experimental results. The mesh of constant size elements on the crack surface can not correctly predict the opening level for fatigue crack as shown in the previous works. The crack opening behavior for the size mesh with a linear change shows almost flat stress level after a crack tip has passed by the monotonic plastic zone. The prediction of crack opening level presents a good agreement with published experimental data regardless of stress ratios, which are using the mesh of the elements that are in proportion to the reversed plastic zone size considering the opening stress intensity factors. Numerical interpolation results of finite element analysis can precisely predict the crack opening level. This method shows a good agreement with the experimental data regardless of the stress ratios and kinds of materials

Uncertainty Quantification of Multi-Phase Closures

Energy Technology Data Exchange (ETDEWEB)

Nadiga, Balasubramanya T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Baglietto, Emilio [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

2017-10-27

In the ensemble-averaged dispersed phase formulation used for CFD of multiphase ows in nuclear reactor thermohydraulics, closures of interphase transfer of mass, momentum, and energy constitute, by far, the biggest source of error and uncertainty. Reliable estimators of this source of error and uncertainty are currently non-existent. Here, we report on how modern Validation and Uncertainty Quanti cation (VUQ) techniques can be leveraged to not only quantify such errors and uncertainties, but also to uncover (unintended) interactions between closures of di erent phenomena. As such this approach serves as a valuable aide in the research and development of multiphase closures. The joint modeling of lift, drag, wall lubrication, and turbulent dispersion|forces that lead to tranfer of momentum between the liquid and gas phases|is examined in the frame- work of validation of the adiabatic but turbulent experiments of Liu and Banko , 1993. An extensive calibration study is undertaken with a popular combination of closure relations and the popular k-ϵ turbulence model in a Bayesian framework. When a wide range of super cial liquid and gas velocities and void fractions is considered, it is found that this set of closures can be validated against the experimental data only by allowing large variations in the coe cients associated with the closures. We argue that such an extent of variation is a measure of uncertainty induced by the chosen set of closures. We also nd that while mean uid velocity and void fraction pro les are properly t, uctuating uid velocity may or may not be properly t. This aspect needs to be investigated further. The popular set of closures considered contains ad-hoc components and are undesirable from a predictive modeling point of view. Consequently, we next consider improvements that are being developed by the MIT group under CASL and which remove the ad-hoc elements. We use non-intrusive methodologies for sensitivity analysis and calibration (using

A kinematic view of loop closure.

Science.gov (United States)

Coutsias, Evangelos A; Seok, Chaok; Jacobson, Matthew P; Dill, Ken A

2004-03-01

We consider the problem of loop closure, i.e., of finding the ensemble of possible backbone structures of a chain segment of a protein molecule that is geometrically consistent with preceding and following parts of the chain whose structures are given. We reduce this problem of determining the loop conformations of six torsions to finding the real roots of a 16th degree polynomial in one variable, based on the robotics literature on the kinematics of the equivalent rotator linkage in the most general case of oblique rotators. We provide a simple intuitive view and derivation of the polynomial for the case in which each of the three pair of torsional axes has a common point. Our method generalizes previous work on analytical loop closure in that the torsion angles need not be consecutive, and any rigid intervening segments are allowed between the free torsions. Our approach also allows for a small degree of flexibility in the bond angles and the peptide torsion angles; this substantially enlarges the space of solvable configurations as is demonstrated by an application of the method to the modeling of cyclic pentapeptides. We give further applications to two important problems. First, we show that this analytical loop closure algorithm can be efficiently combined with an existing loop-construction algorithm to sample loops longer than three residues. Second, we show that Monte Carlo minimization is made severalfold more efficient by employing the local moves generated by the loop closure algorithm, when applied to the global minimization of an eight-residue loop. Our loop closure algorithm is freely available at http://dillgroup. ucsf.edu/loop_closure/. Copyright 2004 Wiley Periodicals, Inc. J Comput Chem 25: 510-528, 2004

Effectiveness of closure of public places with time delay in disease control.

Science.gov (United States)

Wang, Zhenggang; Szeto, Kwok Yip; Leung, Frederick Chi-Ching

2008-08-25

A theoretical basis for the evaluation of the effciency of quarantine measure is developed in a SIR model with time delay. In this model, the effectiveness of the closure of public places such as schools in disease control, modeled as a high degree node in a social network, is evaluated by considering the effect of the time delay in the identification of the infected. In the context of the SIR model, the relation between the number of infectious individuals who are identified with time delay and then quarantined and those who are not identified and continue spreading the virus are investigated numerically. The social network for the simulation is modeled by a scale free network. Closure measures are applied to those infected nodes with high degrees. The effectiveness of the measure can be controlled by the present value of the critical degree K(C): only those nodes with degree higher than K(C) will be quarantined. The cost C(Q) incurred for the closure measure is assumed to be proportional to the total links rendered inactive as a result of the measure, and generally decreases with K(C), while the medical cost C(Q) incurred for virus spreading increases with K(C). The total social cost (C(M) + C(Q)) will have a minimum at a critical K(*), which depends on the ratio of medical cost coeffcient alpha(M) and closure cost coeffcient alpha(Q). Our simulation results demonstrate a mathematical procedure to evaluate the effciency of quarantine measure. Although the numerical work is based on a scale free network, the procedure can be readily generalized and applied to a more realistic social network to determine the proper closure measure in future epidemics.

2003 Initial Assessments of Closure for the C Tank Farm Field Investigation Report (FIR):Numerical Simulations

International Nuclear Information System (INIS)

Zhang, Z F.; Freedman, Vicky L.; White, Mark D.

2003-01-01

In support of CH2M HILL Hanford Group, Inc.'s (CHG) preparation of a Field Investigative Report (FIR) for the closure of the Hanford Site Single-Shell Tank (SST) Waste Management Area (WMA) tank farms, a set of numerical simulations of flow and solute transport was executed to predict the performance of surface barriers for reducing long-term risks from potential groundwater contamination at the C Farm WMA. This report documents the simulation of 14 cases (and two verification cases) involving two-dimensional cross sections through the C Farm WMA tanks C-103 - C-112. Utilizing a unit release scenario at Tank C-112, four different types of leaks were simulated. These simulations assessed the impact of leakage during retrieval, past leaks, and tank residual wastes and tank ancillary equipment following closure activities. . Two transported solutes were considered: uranium-238 (U-238) and technetium-99 (Tc-99). To evaluate the impact of sorption to the subsurface materials, six different retardation coefficients were simulated for U-238. Overall, simulations results for the C Farm WMA showed that only a small fraction of the U-238 with retardation factors greater than 0.6 migrated from the vadose zone in all of the cases. For the conservative solute, Tc-99, results showed that the simulations investigating leakages during retrieval demonstrated the highest WMA peak concentrations and the earliest arrival times due to the high infiltration rate before the use of surface barriers and the addition of water into the system. Simulations investigating past leaks showed similar peaks and arrival times as the retrieval leak cases. Several different release rates were used to investigate contaminant transport from residual tank wastes. All showed similar peak concentrations and arrival times, except for the lowest initial release rate, which was 1,000 times slower than the highest release rate. Past leaks were also investigated with different release rate models, including

Use of a counterfactual approach to evaluate the effect of area closures on fishing location in a tropical tuna fishery.

Directory of Open Access Journals (Sweden)

Tim K Davies

Full Text Available Spatial closures are widely used in marine conservation and fisheries management and it is important to understand their contribution to achieving management objectives. Many previous evaluations of closed area effects have used before-after comparisons, which, without controlling for a full range of factors, cannot ascribe changes in fleet behaviour to area closures per se. In this study we used a counterfactual approach to disentangle the effect of two closed areas on fishing location from other competing effects on the behaviour of the Indian Ocean tuna purse seine fishery. Our results revealed an inconsistent effect of the one of the closed areas between years, after taking into account the influence of environmental conditions on fleet behaviour. This suggests that the policy of closing the area per se was not the main driver for the fleet allocating its effort elsewhere. We also showed a marked difference in effect between the two closed areas resulting from their different locations in the fishery area. These findings highlight the need to account for other key fleet behavioural drivers when predicting or evaluating the contribution of area closures to achieving conservation and fishery management objectives.

Conditional Moment Closure Modelling of a Lifted H2/N2 Turbulent Jet Flame Using the Presumed Mapping Function Approach

Directory of Open Access Journals (Sweden)

Ahmad El Sayed

2015-01-01

Full Text Available A lifted hydrogen/nitrogen turbulent jet flame issuing into a vitiated coflow is investigated using the conditional moment closure (CMC supplemented by the presumed mapping function (PMF approach for the modelling of conditional mixing and velocity statistics. Using a prescribed reference field, the PMF approach yields a presumed probability density function (PDF for the mixture fraction, which is then used in closing the conditional scalar dissipation rate (CSDR and conditional velocity in a fully consistent manner. These closures are applied to a lifted flame and the findings are compared to previous results obtained using β-PDF-based closures over a range of coflow temperatures (Tc. The PMF results are in line with those of the β-PDF and compare well to measurements. The transport budgets in mixture fraction and physical spaces and the radical history ahead of the stabilisation height indicate that the stabilisation mechanism is susceptible to Tc. As in the previous β-PDF calculations, autoignition around the “most reactive” mixture fraction remains the controlling mechanism for sufficiently high Tc. Departure from the β-PDF predictions is observed when Tc is decreased as PMF predicts stabilisation by means of premixed flame propagation. This conclusion is based on the observation that lean mixtures are heated by downstream burning mixtures in a preheat zone developing ahead of the stabilization height. The spurious sources, which stem from inconsistent CSDR modelling, are further investigated. The findings reveal that their effect is small but nonnegligible, most notably within the flame zone.

Transcatheter closure of a large patent ductus arteriosus using jugular access in an infant.

Science.gov (United States)

Fernandes, Precylia; Assaidi, Anass; Baruteau, Alban-Elouen; Fraisse, Alain

2018-03-01

Trans-catheter device closure of patent ductus arteriosus (PDA) via femoral route is the commonly used, safe and effective procedure. Trans-jugular approach has been successfully used in older children with interrupted inferior vena cava. We report a case of successful occlusion of PDA using Amplatzer duct occluder (ADO) via trans-jugular approach following difficulties encountered in gaining femoral venous access. A 6-month-old male infant, weighing 8 kg was admitted for percutaneous catheter closure of PDA. Echocardiogram showed a 4.5 mm duct and left heart dilatation. Femoral venous access was not possible; therefore, we decided to use a trans-jugular approach. The duct was occluded using 8/6 mm ADO. Successful closure of the duct was confirmed with an aortogram. Post procedure echocardiogram showed no residual shunt across the duct. We highlight that trans-catheter closure of PDA using jugular venous access is safe and effective even in infants.

Infering and Calibrating Triadic Closure in a Dynamic Network

Science.gov (United States)

Mantzaris, Alexander V.; Higham, Desmond J.

In the social sciences, the hypothesis of triadic closure contends that new links in a social contact network arise preferentially between those who currently share neighbours. Here, in a proof-of-principle study, we show how to calibrate a recently proposed evolving network model to time-dependent connectivity data. The probabilistic edge birth rate in the model contains a triadic closure term, so we are also able to assess statistically the evidence for this effect. The approach is shown to work on data generated synthetically from the model. We then apply this methodology to some real, large-scale data that records the build up of connections in a business-related social networking site, and find evidence for triadic closure.

Analysis of turbulent conical diffuser flow using second moment closures

International Nuclear Information System (INIS)

Adane, K.K.; Tachie, M.F.; Ormiston, S.J.

2004-01-01

A commercial CFD code, CFX-TASCflow, is used to predict a turbulent conical diffuser flow. The computation was performed using a low-Reynolds number k-ω model, a low-Reynolds number k-ω based non-linear algebraic Reynolds stress model, and a second moment closure with a wall-function. The experimental data of Kassab are used to validate the numerical results. The results show that all the turbulence models reproduce the static pressure coefficient distribution reasonably well. The low Reynolds number k-ω models give better prediction of the friction velocity than the second moment closure. The models also predict the Reynolds shear stress reasonably well but fail to reproduce the correct level of the turbulent kinetic energy. (author)

ASSESSMENT OF LENS THICKNESS IN ANGLE CLOSURE DISEASE

Directory of Open Access Journals (Sweden)

Nishat Sultana Khayoom

2016-08-01

Full Text Available BACKGROUND Anterior chamber depth and lens thickness have been considered as important biometric determinants in primary angle-closure glaucoma. Patients with primary narrow angle may be classified as a primary angle closure suspect (PACS, or as having primary angle closure (PAC or primary angle closure glaucoma (PACG. 23.9% of patients with primary angle closure disease are in India, which highlights the importance of understanding the disease, its natural history, and its underlying pathophysiology, so that we may try to establish effective methods of treatment and preventative measures to delay, or even arrest, disease progression, thereby reducing visual morbidity. AIM To determine the lens thickness using A-scan biometry and its significance in various stages of angle closure disease. MATERIALS AND METHODS Patients attending outpatient department at Minto Ophthalmic Hospital between October 2013 to May 2015 were screened for angle closure disease and subsequently evaluated at glaucoma department. In our study, lens thickness showed a direct correlation with shallowing of the anterior chamber by determining the LT/ ACD ratio. A decrease in anterior chamber depth is proportional to the narrowing of the angle which contributes to the progression of the angle closure disease from just apposition to occlusion enhancing the risk for optic nerve damage and visual field loss. Hence, if the lens thickness values are assessed earlier in the disease process, appropriate intervention can be planned. CONCLUSION Determination of lens changes along with anterior chamber depth and axial length morphometrically can aid in early detection of angle closure. The role of lens extraction for PACG is a subject of increased interest. Lens extraction promotes the benefits of anatomical opening of the angle, IOP reduction and improved vision. This potential intervention may be one among the armamentarium of approaches for PACG. Among the current treatment modalities

Sustainable closure of construction materials quarries in Cuba

Directory of Open Access Journals (Sweden)

Julio Montero-Matos

2017-10-01

Full Text Available The inclusion of effective mine closure plans in the exploitation project is the way to compensate for the harmful effect of this activity. Based on a diagnosis carried out in 11 sites in operation, belonging to the company Canteras, a methodology was designed with a systemic and integral approach that consists of five stages and allows the execution of quarry closures in a sustainable manner. The Delphi method was applied to select the criteria that directly affect the sustainable closure of quarries in such a way that it considers the essential postulates of the Cuban Economic Model (MEC. The proposed methodology represents a contribution to the planning and design of the mining closure in Cuban non-metallic deposits to guarantee the reduction of the environmental impacts caused during its operation and the reduction, to the lesser extent possible, of negative socio-economic effects for the workers and the community located in the area of influence of the quarries. Currently applied in the quarry of San José, in Mayabeque province.

Impact of Different Standard Type A7A Drum Closure-Ring Practices on Gasket Contraction and Bolt Closure Distance– 15621

Energy Technology Data Exchange (ETDEWEB)

Ketusky, Edward [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Blanton, Paul [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Bobbitt, John H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2015-03-11

The Department of Energy, the Savannah River National Laboratory, several manufacturers of specification drums, and the United States Department of Transportation (DOT) are collaborating in the development of a guidance document for DOE contractors and vendors who wish to qualify containers to DOT 7A Type A requirements. Currently, the effort is focused on DOT 7A Type A 208-liter (55-gallons) drums with a standard 12-gauge bolted closure ring. The U.S. requirements, contained in Title 49, Part 178.350 “Specification 7A; general packaging, Type A specifies a competent authority review of the packaging is not required for the transport of (Class 7) radioactive material containing less than Type A quantities of radioactive material. For Type AF drums, a 4 ft. regulatory free drop must be performed, such that the drum “suffers maximum damage.” Although the actual orientation is not defined by the specification, recent studies suggest that maximum damage would result from a shallow angle top impact, where kinetic energy is transferred to the lid, ultimately causing heavy damage to the lid, or even worse, causing the lid to come off. Since each vendor develops closure recommendations/procedures for the drums they manufacture, key parameters applied to drums during closing vary based on vendor. As part of the initial phase of the collaboration, the impact of the closure variants on the ability of the drum to suffer maximum damage is investigated. Specifically, closure testing is performed varying: 1) the amount of torque applied to the closure ring bolt; and, 2) stress relief protocol, including: a) weight of hammer; and, b) orientation that the hammer hits the closure ring. After closure, the amount of drum lid gasket contraction and the distance that the closure bolt moves through the closure ring is measured.

Security option file - After closure (DOS-AF)

International Nuclear Information System (INIS)

2016-01-01

A first volume presents the context and scope of the Cigeo project, and the scope of this document. It proposes a general presentation of Cigeo, the regulatory framework and standards. It describes the different aspects and components of the security strategy: principles, security functions after closure, objectives of protection, global approach. It proposes a security assessment: objectives, consistency with international practices, assessment steps, scenarios, scenario quantitative assessment. The next part addresses security management. The second volume contains a description of the storage system: site characteristics, types of stored parcels, the future of the installation after its closure. The third volume proposes a security assessment. It addresses the management of risks and uncertainties, describes a scenario of normal evolution and also scenarios of altered evolutions, scenarios of unintentional human intrusion, and what-if type scenarios. The fourth volume reports lessons at the current stage of the project, and gives an overview of important activities from storage design to storage closure

Regional neural tube closure defined by the Grainy head-like transcription factors.

Science.gov (United States)

Rifat, Yeliz; Parekh, Vishwas; Wilanowski, Tomasz; Hislop, Nikki R; Auden, Alana; Ting, Stephen B; Cunningham, John M; Jane, Stephen M

2010-09-15

Primary neurulation in mammals has been defined by distinct anatomical closure sites, at the hindbrain/cervical spine (closure 1), forebrain/midbrain boundary (closure 2), and rostral end of the forebrain (closure 3). Zones of neurulation have also been characterized by morphologic differences in neural fold elevation, with non-neural ectoderm-induced formation of paired dorso-lateral hinge points (DLHP) essential for neural tube closure in the cranial and lower spinal cord regions, and notochord-induced bending at the median hinge point (MHP) sufficient for closure in the upper spinal region. Here we identify a unifying molecular basis for these observations based on the function of the non-neural ectoderm-specific Grainy head-like genes in mice. Using a gene-targeting approach we show that deletion of Grhl2 results in failed closure 3, with mutants exhibiting a split-face malformation and exencephaly, associated with failure of neuro-epithelial folding at the DLHP. Loss of Grhl3 alone defines a distinct lower spinal closure defect, also with defective DLHP formation. The two genes contribute equally to closure 2, where only Grhl gene dosage is limiting. Combined deletion of Grhl2 and Grhl3 induces severe rostral and caudal neural tube defects, but DLHP-independent closure 1 proceeds normally in the upper spinal region. These findings provide a molecular basis for non-neural ectoderm mediated formation of the DLHP that is critical for complete neuraxis closure. (c) 2010 Elsevier Inc. All rights reserved.

Urban pavement surface temperature. Comparison of numerical and statistical approach

Science.gov (United States)

Marchetti, Mario; Khalifa, Abderrahmen; Bues, Michel; Bouilloud, Ludovic; Martin, Eric; Chancibaut, Katia

2015-04-01

The forecast of pavement surface temperature is very specific in the context of urban winter maintenance. to manage snow plowing and salting of roads. Such forecast mainly relies on numerical models based on a description of the energy balance between the atmosphere, the buildings and the pavement, with a canyon configuration. Nevertheless, there is a specific need in the physical description and the numerical implementation of the traffic in the energy flux balance. This traffic was originally considered as a constant. Many changes were performed in a numerical model to describe as accurately as possible the traffic effects on this urban energy balance, such as tires friction, pavement-air exchange coefficient, and infrared flux neat balance. Some experiments based on infrared thermography and radiometry were then conducted to quantify the effect fo traffic on urban pavement surface. Based on meteorological data, corresponding pavement temperature forecast were calculated and were compared with fiels measurements. Results indicated a good agreement between the forecast from the numerical model based on this energy balance approach. A complementary forecast approach based on principal component analysis (PCA) and partial least-square regression (PLS) was also developed, with data from thermal mapping usng infrared radiometry. The forecast of pavement surface temperature with air temperature was obtained in the specific case of urban configurtation, and considering traffic into measurements used for the statistical analysis. A comparison between results from the numerical model based on energy balance, and PCA/PLS was then conducted, indicating the advantages and limits of each approach.

The Office of Site Closure: Progress in the Face of Challenges

International Nuclear Information System (INIS)

Fiore, J. J.; Murphie, W. E.; Meador, S. W.

2002-01-01

The Office of Site Closure (OSC) was formed in November 1999 when the Department of Energy's (DOE's) Office of Environmental Management (EM) reorganized to focus specifically on site cleanup and closure. OSC's objective is to achieve safe and cost-effective cleanups and closures that are protective of our workers, the public, and the environment, now and in the future. Since its inception, OSC has focused on implementing a culture of safe closure, with emphasis in three primary areas: complete our responsibility for the Closure Sites Rocky Flats, Mound, Fernald, Ashtabula, and Weldon Spring; complete our responsibility for cleanup at sites where the DOE mission has been completed (examples include Battelle King Avenue and Battelle West Jefferson in Columbus, and General Atomics) or where other Departmental organizations have an ongoing mission (examples include the Brookhaven, Livermore, or Los Alamos National Laboratories, and the Nevada Test Site); and create a framework a nd develop specific business closure tools that will help sites close, such as guidance for and decisions on post-contract benefit liabilities, records retention, and Federal employee incentives for site closure. This paper discusses OSC's 2001 progress in achieving site cleanups, moving towards site closure, and developing specific business closure tools to support site closure. It describes the tools used to achieve progress towards cleanup and closure, such as the application of new technologies, changes in contracting approaches, and the development of agreements between sites and with host states. The paper also identifies upcoming challenges and explores options for how Headquarters and the sites can work together to address these challenges. Finally, it articulates OSC's new focus on oversight of Field Offices to ensure they have the systems in place to oversee contractor activities resulting in site cleanups and closures

Does velopharyngeal closure pattern affect the success of pharyngeal flap pharyngoplasty?

Science.gov (United States)

Armour, Alexis; Fischbach, Simone; Klaiman, Paula; Fisher, David M

2005-01-01

Historically at The Hospital for Sick Children in Toronto, pharyngeal flap pharyngoplasty has been the treatment of choice for treatment of velopharyngeal insufficiency, regardless of velopharyngeal closure pattern. The authors hypothesize that pharyngeal flap pharyngoplasty is more effective in treating velopharyngeal insufficiency in patients with circular or sagittal velopharyngeal closure and less effective in treating the coronal closure pattern. Ninety-three patients who underwent superiorly based pharyngeal flap surgery for velopharyngeal insufficiency were evaluated in a retrospective chart review. Closure pattern was determined preoperatively by nasopharyngoscopy or multiview videofluoroscopy. Nasalance was assessed preoperatively and at 6 weeks and 1 year postoperatively. Nasalance during nonnasal speech was decreased on average, for all closure patterns, postoperatively. However, a significantly higher percentage of patients were corrected to normal nasalance scores in thenoncoronal group than in the coronal group (57 percent versus 35 percent, respectively) at 1 year postoperatively (p approach to the management of velopharyngeal insufficiency and are more inclined to treat coronal pattern velopharyngeal insufficiency with sphincter pharyngoplasty.

Numerical approach of the quantum circuit theory

Energy Technology Data Exchange (ETDEWEB)

Silva, J.J.B., E-mail: jaedsonfisica@hotmail.com; Duarte-Filho, G.C.; Almeida, F.A.G.

2017-03-15

In this paper we develop a numerical method based on the quantum circuit theory to approach the coherent electronic transport in a network of quantum dots connected with arbitrary topology. The algorithm was employed in a circuit formed by quantum dots connected each other in a shape of a linear chain (associations in series), and of a ring (associations in series, and in parallel). For both systems we compute two current observables: conductance and shot noise power. We find an excellent agreement between our numerical results and the ones found in the literature. Moreover, we analyze the algorithm efficiency for a chain of quantum dots, where the mean processing time exhibits a linear dependence with the number of quantum dots in the array.

Numerical approach of the quantum circuit theory

International Nuclear Information System (INIS)

Silva, J.J.B.; Duarte-Filho, G.C.; Almeida, F.A.G.

2017-01-01

In this paper we develop a numerical method based on the quantum circuit theory to approach the coherent electronic transport in a network of quantum dots connected with arbitrary topology. The algorithm was employed in a circuit formed by quantum dots connected each other in a shape of a linear chain (associations in series), and of a ring (associations in series, and in parallel). For both systems we compute two current observables: conductance and shot noise power. We find an excellent agreement between our numerical results and the ones found in the literature. Moreover, we analyze the algorithm efficiency for a chain of quantum dots, where the mean processing time exhibits a linear dependence with the number of quantum dots in the array.

Numerical approach of the quantum circuit theory

Science.gov (United States)

Silva, J. J. B.; Duarte-Filho, G. C.; Almeida, F. A. G.

2017-03-01

In this paper we develop a numerical method based on the quantum circuit theory to approach the coherent electronic transport in a network of quantum dots connected with arbitrary topology. The algorithm was employed in a circuit formed by quantum dots connected each other in a shape of a linear chain (associations in series), and of a ring (associations in series, and in parallel). For both systems we compute two current observables: conductance and shot noise power. We find an excellent agreement between our numerical results and the ones found in the literature. Moreover, we analyze the algorithm efficiency for a chain of quantum dots, where the mean processing time exhibits a linear dependence with the number of quantum dots in the array.

Tight closure and vanishing theorems

International Nuclear Information System (INIS)

Smith, K.E.

2001-01-01

Tight closure has become a thriving branch of commutative algebra since it was first introduced by Mel Hochster and Craig Huneke in 1986. Over the past few years, it has become increasingly clear that tight closure has deep connections with complex algebraic geometry as well, especially with those areas of algebraic geometry where vanishing theorems play a starring role. The purpose of these lectures is to introduce tight closure and to explain some of these connections with algebraic geometry. Tight closure is basically a technique for harnessing the power of the Frobenius map. The use of the Frobenius map to prove theorems about complex algebraic varieties is a familiar technique in algebraic geometry, so it should perhaps come as no surprise that tight closure is applicable to algebraic geometry. On the other hand, it seems that so far we are only seeing the tip of a large and very beautiful iceberg in terms of tight closure's interpretation and applications to algebraic geometry. Interestingly, although tight closure is a 'characteristic p' tool, many of the problems where tight closure has proved useful have also yielded to analytic (L2) techniques. Despite some striking parallels, there had been no specific result directly linking tight closure and L∼ techniques. Recently, however, the equivalence of an ideal central to the theory of tight closure was shown to be equivalent to a certain 'multiplier ideal' first defined using L2 methods. Presumably, deeper connections will continue to emerge. There are two main types of problems for which tight closure has been helpful: in identifying nice structure and in establishing uniform behavior. The original algebraic applications of tight closure include, for example, a quick proof of the Hochster-Roberts theorem on the Cohen-Macaulayness of rings of invariants, and also a refined version of the Brianqon-Skoda theorem on the uniform behaviour of integral closures of powers of ideals. More recent, geometric

Numerical exploration of non-axisymmetric divertor closure in the small angle slot (SAS) divertor at DIII-D

Science.gov (United States)

Frerichs, H.; Schmitz, O.; Covele, B.; Feng, Y.; Guo, H. Y.; Hill, D.

2018-05-01

Numerical simulations of toroidal asymmetries in a tightly baffled small angle slot (SAS) divertor on the DIII-D tokamak show that toroidal asymmetries in divertor closure result in (non-axisymmetric) local onset of detachment within a density window of 10-15% on top of the nominal threshold separatrix density. The SAS divertor is explored at DIII-D for improving access to cold, dissipative/detached divertor conditions. The narrow width of the slot divertor coupled with a small magnetic field line-to-target angle facilitates the buildup of neutral density, thereby increasing radiative and neutrals-related (atoms and molecules) losses in the divertor. Small changes in the strike point location can be expected to have a large impact on divertor conditions. The combination of misaligned slot structure and non-axisymmetric perturbations to the magnetic field configuration causes the strike point to move along the divertor target plate, possibly leaving the divertor slot at some locations. The latter extreme case essentially introduces an opening in the divertor slot from where recycling neutrals can easily escape, and thereby degrade the performance of the slot divertor. Such a strike point dislocation is approximated by a finite gap in the divertor baffle for which 3D edge plasma and neutral gas simulations are performed with the EMC3-EIRENE code.

40 CFR 264.228 - Closure and post-closure care.

Science.gov (United States)

2010-07-01

... remaining wastes to a bearing capacity sufficient to support final cover; and (iii) Cover the surface....112 must include both a plan for complying with paragraph (a)(1) of this section and a contingent plan... practicably removed at closure; and (ii) The owner or operator must prepare a contingent post-closure plan...

A modular approach to numerical human body modeling

NARCIS (Netherlands)

Forbes, P.A.; Griotto, G.; Rooij, L. van

2007-01-01

The choice of a human body model for a simulated automotive impact scenario must take into account both accurate model response and computational efficiency as key factors. This study presents a "modular numerical human body modeling" approach which allows the creation of a customized human body

RCRA corrective action and closure

International Nuclear Information System (INIS)

1995-02-01

This information brief explains how RCRA corrective action and closure processes affect one another. It examines the similarities and differences between corrective action and closure, regulators' interests in RCRA facilities undergoing closure, and how the need to perform corrective action affects the closure of DOE's permitted facilities and interim status facilities

Primary closure after carotid endarterectomy is not inferior to other closure techniques.

Science.gov (United States)

Avgerinos, Efthymios D; Chaer, Rabih A; Naddaf, Abdallah; El-Shazly, Omar M; Marone, Luke; Makaroun, Michel S

2016-09-01

Primary closure after carotid endarterectomy (CEA) has been much maligned as an inferior technique with worse outcomes than in patch closure. Our purpose was to compare perioperative and long-term results of different CEA closure techniques in a large institutional experience. A consecutive cohort of CEAs between January 1, 2000, and December 31, 2010, was retrospectively analyzed. Closure technique was used to divide patients into three groups: primary longitudinal arteriotomy closure (PRC), patch closure (PAC), and eversion closure (EVC). End points were perioperative events, long-term strokes, and restenosis ≥70%. Multivariate regression models were used to assess the effect of baseline predictors. There were 1737 CEA cases (bilateral, 143; mean age, 71.4 ± 9.3 years; 56.2% men; 35.3% symptomatic) performed during the study period with a mean clinical follow-up of 49.8 ± 36.4 months (range, 0-155 months). More men had primary closure, but other demographic and baseline symptoms were similar between groups. Half the patients had PAC, with the rest evenly distributed between PRC and EVC. The rate of nerve injury was 2.7%, the rate of reintervention for hematoma was 1.5%, and the length of hospital stay was 2.4 ± 3.0 days, with no significant differences among groups. The combined stroke and death rate was 2.5% overall and 3.9% and 1.7% in the symptomatic and asymptomatic cohort, respectively. Stroke and death rates were similar between groups: PRC, 11 (2.7%); PAC, 19 (2.2%); EVC, 13 (2.9%). Multivariate analysis showed baseline symptomatic disease (odds ratio, 2.4; P = .007) and heart failure (odds ratio, 3.1; P = .003) as predictors of perioperative stroke and death, but not the type of closure. Cox regression analysis demonstrated, among other risk factors, no statin use (hazard ratio, 2.1; P = .008) as a predictor of ipsilateral stroke and severe (glomerular filtration rate <30 mL/min/1.73 m(2)) renal insufficiency (hazard ratio, 2.6; P�

Review of Methods and Approaches for Deriving Numeric ...

Science.gov (United States)

EPA will propose numeric criteria for nitrogen/phosphorus pollution to protect estuaries, coastal areas and South Florida inland flowing waters that have been designated Class I, II and III , as well as downstream protective values (DPVs) to protect estuarine and marine waters. In accordance with the formal determination and pursuant to a subsequent consent decree, these numeric criteria are being developed to translate and implement Florida’s existing narrative nutrient criterion, to protect the designated use that Florida has previously set for these waters, at Rule 62-302.530(47)(b), F.A.C. which provides that “In no case shall nutrient concentrations of a body of water be altered so as to cause an imbalance in natural populations of aquatic flora or fauna.” Under the Clean Water Act and EPA’s implementing regulations, these numeric criteria must be based on sound scientific rationale and reflect the best available scientific knowledge. EPA has previously published a series of peer reviewed technical guidance documents to develop numeric criteria to address nitrogen/phosphorus pollution in different water body types. EPA recognizes that available and reliable data sources for use in numeric criteria development vary across estuarine and coastal waters in Florida and flowing waters in South Florida. In addition, scientifically defensible approaches for numeric criteria development have different requirements that must be taken into consider

Downstreamness: A concept to analyse basin closure

NARCIS (Netherlands)

van Oel, P.R.; Krol, Martinus S.; Hoekstra, Arjen Ysbert

2011-01-01

In many places in the world, increasing water demands have led to the development of infrastructure for freshwater storage and irrigation. Especially in water-scarce regions, this development has led to a growing number of concerns about basin closure. These concerns ask for a structured approach

Some numerical approaches of creep, thermal shock, damage

Indian Academy of Sciences (India)

Creep can be satisfactorily described by a kinematic hardening, and exhibits different creep rates in tension and compression. Concerning the thermal shock of materials, the numerical approach depends whether or not the material is able to develop a sprayed out damage, leading to micro- or macro-cracking. Finally ...

Development of high fidelity soot aerosol dynamics models using method of moments with interpolative closure

KAUST Repository

Roy, Subrata P.

2014-01-28

The method of moments with interpolative closure (MOMIC) for soot formation and growth provides a detailed modeling framework maintaining a good balance in generality, accuracy, robustness, and computational efficiency. This study presents several computational issues in the development and implementation of the MOMIC-based soot modeling for direct numerical simulations (DNS). The issues of concern include a wide dynamic range of numbers, choice of normalization, high effective Schmidt number of soot particles, and realizability of the soot particle size distribution function (PSDF). These problems are not unique to DNS, but they are often exacerbated by the high-order numerical schemes used in DNS. Four specific issues are discussed in this article: the treatment of soot diffusion, choice of interpolation scheme for MOMIC, an approach to deal with strongly oxidizing environments, and realizability of the PSDF. General, robust, and stable approaches are sought to address these issues, minimizing the use of ad hoc treatments such as clipping. The solutions proposed and demonstrated here are being applied to generate new physical insight into complex turbulence-chemistry-soot-radiation interactions in turbulent reacting flows using DNS. © 2014 Copyright Taylor and Francis Group, LLC.

Streamlined approach for environmental restoration work plan for Corrective Action Unit 126: Closure of aboveground storage tanks, Nevada Test Site, Nevada. Revision 1

International Nuclear Information System (INIS)

1998-07-01

This plan addresses the closure of several aboveground storage tanks in Area 25 of the Nevada Test Site. The unit is currently identified as Corrective Action Unit 126 in the Federal Facility Agreement and Consent Order and is listed as having six Corrective Action Sites. This plan addresses the Streamlined Approach for Environmental Restoration closure for five of the six sites. Four of the CASs are located at the Engine Test Stand complex and one is located in the Central Support Area. The sites consist of aboveground tanks, two of which were used to store diesel fuel and one stored Nalcool (an antifreeze mixture). The remaining tanks were used as part of a water demineralization process and stored either sulfuric acid or sodium hydroxide, and one was used as a charcoal adsorption furnace. Closure will be completed by removal of the associated piping, tank supports and tanks using a front end loader, backhoe, and/or crane. When possible, the tanks will be salvaged as scrap metal. The piping that is not removed will be sealed using a cement grout

200 West Area Ash Pit Demolition Site closure plan. Revision 1

International Nuclear Information System (INIS)

Ruck, F.R.

1994-01-01

The Ash Pit Demolition Site had two known demolition events, the first occurred in November of 1984, and the second occurred in June of 1986. These demolition events were a form of thermal treatment for discarded explosive chemical products. Because the Ash Pit Demolition Site will no longer be used for this thermal activity, the site will be closed. Closure will be conducted pursuant to the requirements of the Washington State Department of Ecology (Ecology) ''Dangerous Waste Regulations'', Washington Administrative Code (WAC) 173-303-610 and 40 Code of Federal Regulations (CFR) 270.1. The 200 West Area Ash Pit Demolition Site Closure Plan consists of a Part A, Form 3, Dangerous Waste Permit Application (Revision 4) and a closure plan. An explanation of the Part A, Form 3, submitted with this closure plan is provided at the beginning of the Part A Section. The closure plan consists of nine chapters and five appendices. This closure plan presents a description of the Ash,Pit Demolition Site, the history of the waste treated, and the approach that will be followed to close the Ash Pit Demolition Site. Because there were no radioactively contaminated chemicals involved in the demolitions, the information on radionuclides is provided for ''information only''. Remediation of any radioactive contamination is not within the scope of this closure plan. Only dangerous constituents derived from Ash Pit Demolition Site operations will be addressed in this closure plan in accordance with WAC 173-303-610(2)(b)(i)

European Hernia Society guidelines on the closure of abdominal wall incisions

DEFF Research Database (Denmark)

Muysoms, F E; Antoniou, S A; Bury, K

2015-01-01

using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach and methodological guidance was taken from Scottish Intercollegiate Guidelines Network (SIGN). The literature search included publications up to April 2014. The guidelines were written using the AGREE II...... of rapidly absorbable sutures. It is suggested using a slowly absorbable monofilament suture in a single layer aponeurotic closure technique without separate closure of the peritoneum. A small bites technique with a suture to wound length (SL/WL) ratio at least 4/1 is the current recommended method......, it is suggested using the smallest trocar size adequate for the procedure and closure of the fascial defect if trocars larger or equal to 10 mm are used. For single incision laparoscopic surgery, we suggest meticulous closure of the fascial incision to avoid an increased risk of incisional hernias....

Numerical consistency check between two approaches to radiative ...

Indian Academy of Sciences (India)

approaches for a consistency check on numerical accuracy, and find out the stabil- ... ln(MR/1 GeV) to top-quark mass scale t0(= ln(mt/1 GeV)) where t0 ≤ t ≤ tR, we ..... It is in general to tone down the solar mixing angle through further fine.

Environmental risk assessment as the basis for mine closure at Iscor Mining

Energy Technology Data Exchange (ETDEWEB)

Swart, S.J.; Pulles, W.; Boer, R.H.; Kirkaldy, J.; Pettit, C. [Iscor Mining, Pretoria (South Africa). Environmental Management Services

1998-01-01

This paper discusses the principles and application of risk assessment and management as the basis for environmental management within the mining industry. Unlike in other industries, mines are required to obtain closure certificates in terms of section 12 for the South African Minerals Act, which should ultimately release them from further environmental responsibilities. The focus shifts from conventional minimum legal compliance management to management of real environmental risks. The risk assessment approach has been applied to the planning of mine closure at Iscor`s Durban Navigation Collieries (Durnacol) in Kwa-Zulu Natal and certain key risk issues such as the long-term risk of water pollution from coal discard dumps have already progressed to fully quantitative risk assessment. This paper discussed the process which has been followed to date, with particular emphasis on the most recent phase, namely quantitative risk assessment and management of pollution from coal discard dumps. it is believed that the approach that is being pioneered at Durnacoal and which overcomes some of the more obvious deficineices of both the Environmental Risk Assessment Management (EMPR) and the traditional process will ultimately serve as the mode for all responsible mines in South Africa. It is also believed that this approach will enable the authorities to issue closure certificates with the confidence that there will be no unforeseen surprises in the years after closure. 9 figs., 1 tab.

Ring closure in actin polymers

Energy Technology Data Exchange (ETDEWEB)

Sinha, Supurna, E-mail: supurna@rri.res.in [Raman Research Institute, Bangalore 560080 (India); Chattopadhyay, Sebanti [Doon University, Dehradun 248001 (India)

2017-03-18

We present an analysis for the ring closure probability of semiflexible polymers within the pure bend Worm Like Chain (WLC) model. The ring closure probability predicted from our analysis can be tested against fluorescent actin cyclization experiments. We also discuss the effect of ring closure on bend angle fluctuations in actin polymers. - Highlights: • Ring closure of biopolymers. • Worm like chain model. • Predictions for experiments.

Transcatheter closure of atrial septal defect in a patient with Noonan syndrome after corrective surgery

Directory of Open Access Journals (Sweden)

Mangovski Ljupčo

2015-01-01

Full Text Available Introduction. Transcatheter atrial septal defect (ASD closure is considered to be a gold standard for patients with the suitable anatomy as compared to cardiac surgery. Reocurrence of ASD after surgical closure is a very rare late complication which can be successfully managed with transcatheter procedure. Case report. We reported a female patient with Noonan syndrome who presented with hemodinamically significant ASD 37 years after the corrective cardiac surgery. Due to numerous comorbidities which included severe kyphoscoliosis, pectus excavatum and multiple surgeries we decided to perform transcatheter closure of ASD. The procedure itself was very challenging due to the patient’s short stature and heart’s orientation in the chest, but was performed successfully. The subsequent follow-up was uneventful and the patient reported improvement in the symptoms. Conclusion. Transcatheter closure of ASD in a patient with Noonan syndrome with the history of surgically corrected ASD can be performed successfully, despite challenging chest anatomy.

Performance Objective for Tank Farm Closure Risk Assessments

International Nuclear Information System (INIS)

MANN, F.M.; KNEPP, A.J.; BADDEN, J.

2003-01-01

To be meaningful, results from a numeric risk assessment of the consequences of an action must be compared against the standards for such an action. That is, before one disposes of waste or closes a facility with waste, one must show that the disposal or closure action protects the public health and safety and the environment. These standards are called performance objectives. Regulations requiring performing performance assessments, (whether federal ones like the Department of Energy [DOE] Order 435.1, Radioactive Waste Management and its implementing guides or Washington State ones like the regulations implementing the Washington Administrative Code [WAC] 173-340 ''Model Toxics Control Act - Cleanup''), usually require that the determination of performance objectives be one of the first steps performed. These performance objectives not only set comparison level for the numeric results, but also define the media, pathways, exposure scenarios (receptors), spatial locations, and times that the performance assessment must consider. Thus, a performance objective consists of a compliance level, place(s) of compliance, and time(s) of compliance. Performance objectives are not the levels that a regulatory agency will enforce in a permit or authorization. Those levels, often called enforcement levels, will be set in the permit or authorization. Rather, performance objectives are those levels against which the results of the numeric simulation will be compared to judge the success of the proposed cleanup or disposal actions. Additional comparison levels may be requested for information purposes, but are not officially part of the decision on the adequacy of the proposed action. To emphasize that the performance objectives discussed in this document are not regulatory performance objectives, the three components of the performance objective will be renamed in this document as assessment standard, point(s) of assessment, and time(s) of assessment. However, whenever

A review of numerical techniques approaching microstructures of crystalline rocks

Science.gov (United States)

Zhang, Yahui; Wong, Louis Ngai Yuen

2018-06-01

The macro-mechanical behavior of crystalline rocks including strength, deformability and failure pattern are dominantly influenced by their grain-scale structures. Numerical technique is commonly used to assist understanding the complicated mechanisms from a microscopic perspective. Each numerical method has its respective strengths and limitations. This review paper elucidates how numerical techniques take geometrical aspects of the grain into consideration. Four categories of numerical methods are examined: particle-based methods, block-based methods, grain-based methods, and node-based methods. Focusing on the grain-scale characters, specific relevant issues including increasing complexity of micro-structure, deformation and breakage of model elements, fracturing and fragmentation process are described in more detail. Therefore, the intrinsic capabilities and limitations of different numerical approaches in terms of accounting for the micro-mechanics of crystalline rocks and their phenomenal mechanical behavior are explicitly presented.

Tubular closure device

International Nuclear Information System (INIS)

Klahn, F.C.; Nolan, J.H.; Wills, C.

1982-01-01

This invention relates to a closure mechanism for closing openings such as the bore of a conduit and for releasably securing members within the bore. More particularly, this invention relates to a closure mechanism for tubular irradiation surveillance specimen assembly holders used in nuclear reactors

A cubic B-spline Galerkin approach for the numerical simulation of the GEW equation

Directory of Open Access Journals (Sweden)

S. Battal Gazi Karakoç

2016-02-01

Full Text Available The generalized equal width (GEW wave equation is solved numerically by using lumped Galerkin approach with cubic B-spline functions. The proposed numerical scheme is tested by applying two test problems including single solitary wave and interaction of two solitary waves. In order to determine the performance of the algorithm, the error norms L2 and L∞ and the invariants I1, I2 and I3 are calculated. For the linear stability analysis of the numerical algorithm, von Neumann approach is used. As a result, the obtained findings show that the presented numerical scheme is preferable to some recent numerical methods.  

Hybrid approach for transcatheter paravalvular leak closure of mitral prosthesis in high-risk patients through transapical access.

Science.gov (United States)

Davidavicius, Giedrius; Rucinskas, Kestutis; Drasutiene, Agne; Samalavicius, Robertas; Bilkis, Valdas; Zakarkaite, Diana; Aidietis, Audrius

2014-11-01

To report "hybrid" procedure feasibility and the clinical success of transcatheter paravalvular leak closure through apical access. Seven patients (73.6±6.1 years; 4 men) with severe mitral prosthesis paravalvular leak were selected. All patients were at high risk for open surgery because of severe comorbidities and heart failure (New York Heart Association class III-IV). The defect size was 25±7.8 mm in the long axis and 9.3±2 mm in the short axis. Two defects were detected in 2 patients. The transapical procedure was performed in a "hybrid" surgery room using minithoracotomy and general anesthesia. Three-dimensional transesophageal echocardiography and fluoroscopy were used for imaging. A total of 19 Amplatzer Vascular Plug III devices (St Jude Medical) were implanted in 7 patients, 2.7/patient and 1 to 3/fistula. The procedure time was 150.7±66.8 minutes. In 6 of 7 patients (85.7%), the paravalvular leak was successfully closed, resulting in no or mild residual regurgitation. One patient had moderate regurgitation despite deployment of 3 Amplatzer Vascular Plug III devices. Two patients required blood transfusion related to procedural blood loss. The patients were discharged at 15.3±6.5 days and followed up at 215.7±138.6 days. All but 1 patient reported symptomatic improvement by ≥1 New York Heart Association class at follow-up. One patient died 216 days postoperatively. A "hybrid approach" for transcatheter paravalvular leak closure of mitral prosthesis from the apical route is effective in reducing the regurgitation grade and improving functional capacity in high-risk patients. Complete closure of the defect was maintained at follow-up in most patients. Copyright © 2014 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

218-E-8 Borrow Pit Demolition Site closure plan. Revision 1

International Nuclear Information System (INIS)

Ruck, F.R.

1994-01-01

The 218-E-8 Demolition Site was the site of a single demolition event in November of 1984. This demolition event was a form of thermal treatment for discarded explosive chemical products. Because the 218-E-8 Demolition Site will no longer be used for this thermal activity, the site will be closed. Closure will be conducted pursuant to the requirements of the Washington State Department of Ecology (Ecology) ''Dangerous Waste Regulations,'' Washington Administrative Code (WAC) 173-303-610 and 40 Code of Federal Regulations (CFR) 270.1. The 218-E-8 Borrow Pit Demolition Site Closure Plan consists of a Hanford Facility Dangerous Waste Part A Permit Application, Form 3, Revision 4, and a closure plan. An explanation of the Part A Form 3, submitted with this closure plan is provided at the beginning of the Part A Section. The closure plan consists of nine chapters and five appendices. This closure plan presents a description of the 218-E-8 Demolition Site, the history of the waste treated, and the approach that will be followed to close the 218-E-8 Demolition Site. Because there were no radioactively contaminated chemicals involved in t he demolitions at the 218-E-8 Borrow Pit site, the information on radionuclides is provided for ''information only.'' Remediation of any radioactive contamination is not within the scope of this closure plan. Only dangerous constituents derived from 218-E-8 Demolition Site operations will be addressed in this closure plan in accordance with WAC 173-303-610(2)(b)(i)

Comparison of Subcuticular Suture Materials in Cesarean Skin Closure

Directory of Open Access Journals (Sweden)

Pınar Solmaz Hasdemir

2015-01-01

Full Text Available Aim. Comparison of the rate of wound complications, pain, and patient satisfaction based on used subcuticular suture material. Methods. A total of 250 consecutive women undergoing primary and repeat cesarean section with low transverse incision were prospectively included. The primary outcome was wound complication rate including infection, dehiscence, hematoma, and hypertrophic scar formation within a 6-week period after operation. Secondary outcomes were skin closure time, the need for use of additional analgesic agent, pain score on numeric rating scale, cosmetic score, and patient scar satisfaction scale. Results. Absorbable polyglactin was used in 108 patients and nonabsorbable polypropylene was used in 142 patients. Wound complication rates were similar in primary and repeat cesarean groups based on the type of suture material. Skin closure time is longer in nonabsorbable suture material group in both primary and repeat cesarean groups. There was no difference between groups in terms of postoperative pain, need for additional analgesic use, late phase pain, and itching at the scar. Although the cosmetic results tended to be better in the nonabsorbable group in primary surgery patients, there was no significant difference in the visual satisfaction of the patients. Conclusions. Absorbable and nonabsorbable suture materials are comparable in cesarean section operation skin closure.

CIRSE Vascular Closure Device Registry

NARCIS (Netherlands)

Reekers, Jim A.; Müller-Hülsbeck, Stefan; Libicher, Martin; Atar, Eli; Trentmann, Jens; Goffette, Pierre; Borggrefe, Jan; Zeleňák, Kamil; Hooijboer, Pieter; Belli, Anna-Maria

2011-01-01

Vascular closure devices are routinely used after many vascular interventional radiology procedures. However, there have been no major multicenter studies to assess the safety and effectiveness of the routine use of closure devices in interventional radiology. The CIRSE registry of closure devices

Transcatheter closure of Patent Ductus Arteriosus through only venous route.

Science.gov (United States)

Sheikh, Abdul Malik; Duke, Abdul Karim; Sattar, Hina

2018-03-01

Patent ductus arteriosus is a common congenital cardiac defect comprising 5-10% of all these defects in term neonates. Although open chest and video-assisted interruption are still in use, transcatheter occlusion has rapidly become the first choice for patent ductus arteriosus closure in the appropriate patient. Percutaneous closure of patent ductus arteriosus is widely done by transvenous approach guided by aortic access. We present the case of a 2 year old girl who underwent patent ductus arteriosus device occlusion with transvenous access only.

Numerical schemes for one-point closure turbulence models

International Nuclear Information System (INIS)

Larcher, Aurelien

2010-01-01

First-order Reynolds Averaged Navier-Stokes (RANS) turbulence models are studied in this thesis. These latter consist of the Navier-Stokes equations, supplemented with a system of balance equations describing the evolution of characteristic scalar quantities called 'turbulent scales'. In so doing, the contribution of the turbulent agitation to the momentum can be determined by adding a diffusive coefficient (called 'turbulent viscosity') in the Navier-Stokes equations, such that it is defined as a function of the turbulent scales. The numerical analysis problems, which are studied in this dissertation, are treated in the frame of a fractional step algorithm, consisting of an approximation on regular meshes of the Navier-Stokes equations by the nonconforming Crouzeix-Raviart finite elements, and a set of scalar convection-diffusion balance equations discretized by the standard finite volume method. A monotone numerical scheme based on the standard finite volume method is proposed so as to ensure that the turbulent scales, like the turbulent kinetic energy (k) and its dissipation rate (ε), remain positive in the case of the standard k - ε model, as well as the k - ε RNG and the extended k - ε - ν 2 models. The convergence of the proposed numerical scheme is then studied on a system composed of the incompressible Stokes equations and a steady convection-diffusion equation, which are both coupled by the viscosities and the turbulent production term. This reduced model allows to deal with the main difficulty encountered in the analysis of such problems: the definition of the turbulent production term leads to consider a class of convection-diffusion problems with an irregular right-hand side belonging to L 1 . Finally, to step towards the unsteady problem, the convergence of the finite volume scheme for a model convection-diffusion equation with L 1 data is proved. The a priori estimates on the solution and on its time derivative are obtained in discrete norms, for

Transversal magnetotransport in Weyl semimetals: Exact numerical approach

Science.gov (United States)

Behrends, Jan; Kunst, Flore K.; Sbierski, Björn

2018-02-01

Magnetotransport experiments on Weyl semimetals are essential for investigating the intriguing topological and low-energy properties of Weyl nodes. If the transport direction is perpendicular to the applied magnetic field, experiments have shown a large positive magnetoresistance. In this work we present a theoretical scattering matrix approach to transversal magnetotransport in a Weyl node. Our numerical method confirms and goes beyond the existing perturbative analytical approach by treating disorder exactly. It is formulated in real space and is applicable to mesoscopic samples as well as in the bulk limit. In particular, we study the case of clean and strongly disordered samples.

Neutrinoless double-β decay of Se82 in the shell model: Beyond the closure approximation

Science.gov (United States)

Sen'kov, R. A.; Horoi, M.; Brown, B. A.

2014-05-01

We recently proposed a method [R. A. Senkov and M. Horoi, Phys. Rev. C 88, 064312 (2013), 10.1103/PhysRevC.88.064312] to calculate the standard nuclear matrix elements for neutrinoless double-β decay (0νββ) of Ca48 going beyond the closure approximation. Here we extend this analysis to the important case of Se82, which was chosen as the base isotope for the upcoming SuperNEMO experiment. We demonstrate that by using a mixed method that considers information from closure and nonclosure approaches, one can get excellent convergence properties for the nuclear matrix elements, which allows one to avoid unmanageable computational costs. We show that in contrast with the closure approximation the mixed approach has a very weak dependence on the average closure energy. The matrix elements for the heavy neutrino-exchange mechanism that could contribute to the 0νββ decay of Se82 are also presented.

3718-F Alkali Metal Treatment and Storage Facility Closure Plan

International Nuclear Information System (INIS)

1992-11-01

The Hanford Site, located northwest of the city of Richland, Washington, houses reactors, chemical-separation systems, and related facilities used for the production of special nuclear materials, as well as for activities associated with nuclear energy development. The 300 Area of the Hanford Site contains reactor fuel manufacturing facilities and several research and development laboratories. The 3718-F Alkali Metal Treatment and Storage Facility (3718-F Facility), located in the 300 Area, was used to store and treat alkali metal wastes. Therefore, it is subject to the regulatory requirements for the storage and treatment of dangerous wastes. Closure will be conducted pursuant to the requirements of the Washington Administrative Code (WAC) 173-303-610 (Ecology 1989) and 40 CFR 270.1. Closure also will satisfy the thermal treatment facility closure requirements of 40 CFR 265.381. This closure plan presents a description of the 3718-F Facility, the history of wastes managed, and the approach that will be followed to close the facility. Only hazardous constituents derived from 3718-F Facility operations will be addressed

Strategy for a numerical Rock Mechanics Site Descriptive Model. Further development of the theoretical/numerical approach

International Nuclear Information System (INIS)

Olofsson, Isabelle; Fredriksson, Anders

2005-05-01

The Swedish Nuclear and Fuel Management Company (SKB) is conducting Preliminary Site Investigations at two different locations in Sweden in order to study the possibility of a Deep Repository for spent fuel. In the frame of these Site Investigations, Site Descriptive Models are achieved. These products are the result of an interaction of several disciplines such as geology, hydrogeology, and meteorology. The Rock Mechanics Site Descriptive Model constitutes one of these models. Before the start of the Site Investigations a numerical method using Discrete Fracture Network (DFN) models and the 2D numerical software UDEC was developed. Numerical simulations were the tool chosen for applying the theoretical approach for characterising the mechanical rock mass properties. Some shortcomings were identified when developing the methodology. Their impacts on the modelling (in term of time and quality assurance of results) were estimated to be so important that the improvement of the methodology with another numerical tool was investigated. The theoretical approach is still based on DFN models but the numerical software used is 3DEC. The main assets of the programme compared to UDEC are an optimised algorithm for the generation of fractures in the model and for the assignment of mechanical fracture properties. Due to some numerical constraints the test conditions were set-up in order to simulate 2D plane strain tests. Numerical simulations were conducted on the same data set as used previously for the UDEC modelling in order to estimate and validate the results from the new methodology. A real 3D simulation was also conducted in order to assess the effect of the '2D' conditions in the 3DEC model. Based on the quality of the results it was decided to update the theoretical model and introduce the new methodology based on DFN models and 3DEC simulations for the establishment of the Rock Mechanics Site Descriptive Model. By separating the spatial variability into two parts, one

Combined perventricular septal defect closure and patent ductus arteriosus ligation via the lower ministernotomy approach.

Science.gov (United States)

Voitov, Alexey; Omelchenko, Alexander; Gorbatykh, Yuriy; Bogachev-Prokophiev, Alexander; Karaskov, Alexander

2018-02-01

Over the past decade, minimally invasive approaches have been advocated for surgical correction of congenital defects to reduce costs related to hospitalization and for improved cosmesis. Minimal skin incisions and partial sternotomy reduce surgical trauma, however these techniques might not be successful in treating a number of congenital pathological conditions, particularly for combined congenital defects. We focused on cases with a combined presentation of ventricular septal defect and patent ductus arteriosus. We studied 12 infants who successfully underwent surgical treatment for a combined single-stage ventricular septal defect and patent ductus arteriosus closure through a lower ministernotomy without using cardiopulmonary bypass and X-rays. No intraoperative and early postoperative complications or mortality were noted. Postoperative echocardiography did not reveal residual shunts. The proposed technique is safe and reproducible in infants. © Crown copyright 2017.

Risk and Performance Analyses Supporting Closure of WMA C at the Hanford Site in Southeast Washington

International Nuclear Information System (INIS)

Eberlein, Susan J.; Bergeron, Marcel P.; Kemp, Christopher J.; Hildebrand, R. Douglas; Aly, Alaa; Kozak, Matthew; Mehta, Sunil; Connelly, Michael

2013-01-01

construction of detailed numerical models of WMA C using the Subsurface Transport Over Multiple Phases (STOMP©) computer code, the development of a technical approach for abstraction of a range of representative STOMP© simulations into a system-level model based on the GoldSim© system-level model software.The STOMP©-based models will be used to evaluate local-scale impacts and closed facility performance over a sufficient range of simulations to allow for development of the system-level model of the WMA C. The GoldSim©-based system-level model will be used to evaluate overall sensitivity of modeled parameters and the estimate the uncertainty in potential future impacts from a closed WMA C facility

Risk and Performance Analyses Supporting Closure of WMA C at the Hanford Site in Southeast Washington

Energy Technology Data Exchange (ETDEWEB)

Eberlein, Susan J.; Bergeron, Marcel P.; Kemp, Christopher J.

2013-11-11

construction of detailed numerical models of WMA C using the Subsurface Transport Over Multiple Phases (STOMP©) computer code, the development of a technical approach for abstraction of a range of representative STOMP© simulations into a system-level model based on the GoldSim© system-level model software.The STOMP©-based models will be used to evaluate local-scale impacts and closed facility performance over a sufficient range of simulations to allow for development of the system-level model of the WMA C. The GoldSim©-based system-level model will be used to evaluate overall sensitivity of modeled parameters and the estimate the uncertainty in potential future impacts from a closed WMA C facility.

Observations on early and delayed colostomy closure.

Science.gov (United States)

Tade, A O; Salami, B A; Ayoade, B A

2011-06-01

Traditional treatment of a variety of colorectal pathologies had included a diverting colostomy that was closed eight or more weeks later during a readmission. The aim of this retrospective study was to determine the outcomes of early colostomy closure and delayed colostomy closure in patients with temporary colostomies following traumatic and non-traumatic colorectal pathologies. In this study early colostomy closure was the closure of a colostomy within three weeks of its construction, while delayed colostomy closure referred to closure after 3 weeks. Complete records of the 37 adult patients who had temporary colostomy constructed and closed between Jan. 1997 December 2003 for various colorectal pathologies were studied. Fourteen patients had early colostomy closure while 23 had delayed closure. In the early colostomy closure group there were 10 men and 4 women. The mean age of the patients was 28yr with a range of 18-65yr. Colostomies were closed 9-18 days after initial colostomy construction. There was no mortality. Morbidity rate 28.6% (4 out of 14). There were two faecal fistulas (14.3%). Twenty-three patients had delayed colostomy closure 8 weeks to 18 months after initial colostomy construction. These were patients unfit for early surgery after initial colostomy construction because of carcinoma, significant weight loss, or sepsis. There was no mortality. Morbidity rate was 26.1%. There were 3 faecal fistulas (13.2%). Outcomes following early colostomy closure and delayed closure were comparable. Patients fit for surgery should have early closure whilst patients who may have compromised health should have delayed closure.

Flow and transport simulation of Madeira River using three depth-averaged two-equation turbulence closure models

Directory of Open Access Journals (Sweden)

Li-ren Yu

2012-03-01

Full Text Available This paper describes a numerical simulation in the Amazon water system, aiming to develop a quasi-three-dimensional numerical tool for refined modeling of turbulent flow and passive transport of mass in natural waters. Three depth-averaged two-equation turbulence closure models, k˜−ε˜,k˜−w˜, and k˜−ω˜ , were used to close the non-simplified quasi-three dimensional hydrodynamic fundamental governing equations. The discretized equations were solved with the advanced multi-grid iterative method using non-orthogonal body-fitted coarse and fine grids with collocated variable arrangement. Except for steady flow computation, the processes of contaminant inpouring and plume development at the beginning of discharge, caused by a side-discharge of a tributary, have also been numerically investigated. The three depth-averaged two-equation closure models are all suitable for modeling strong mixing turbulence. The newly established turbulence models such as the k˜−ω˜ model, with a higher order of magnitude of the turbulence parameter, provide a possibility for improving computational precision.

Sternal exploration or closure

Science.gov (United States)

VAC - vacuum-assisted closure - sternal wound; Sternal dehiscence; Sternal infection ... in the wound to look for signs of infection Remove dead or infected ... use a VAC (vacuum-assisted closure) dressing. It is a negative ...

16. Optimal guidance of percutaneous device closure of PDA by transthoracic echocardiography

Directory of Open Access Journals (Sweden)

M. Alobaidan

2016-07-01

Full Text Available Patent ductus arteriosus (PDA is common congenital cardiac lesion and the most accepted way of management is transcatheter occlusion by device which is usually done under fluoroscopy guidance. Transoesophageal echo cardiography and transaortic imaging were used in adult to guide the procedure which is with certain applications in pediatric age group transthoracic echocardiography (TTE in pediatric population provides excellent images for PDA and may replace the use of fluoroscopy to guide PDA closure at least in special situations. To highlight the feasibility of device closure under guidance of TTE to be applied in sick patients who are not suitable for transfer to cardiac catheter laboratory or those with contraindication to contrast and or radiation application. 18 patients from July 2013 to May 2015 underwent TTE guidance device closure of PDA, 1 patient was excluded after device embolization which necessitate retrieval under fluoroscopy (fluoro.. Conscious sedation was used in 17 patients except 1 who was sick and already ventilated in ICU, there were 11 female and 7 male, antegrade approach was used in 10 patients with partial fluoro and retrograde approach in 8 patients without fluoro. Median age is 7 months, median weight is 8 kg (3.2–11 kg, 2 patients with renal impairment, 2 with Leukemia, median procedure time is 35 min, median fluoro. is 2.2 min, PDA size were small in 13 patients and moderate in 5, immediate closure is achieved in all. The devices were ADOI, ADOS, ADOII, Occlutech, and AVP2. Device embolization in 1 with successful retrieval and second device was used with complete closure percutaneous PDA closure under TTE guidance is feasible, safe and recommended in selected patients with certain situation.

Modelling and numerical simulation of two-phase flows using the two-fluid two-pressure approach; Modelisation et simulation numerique des ecoulements diphasiques par une approche bifluide a deux pressions

Energy Technology Data Exchange (ETDEWEB)

Guillemaud, V

2007-03-15

This thesis is devoted to the modelling and numerical simulation of liquid-vapor flows. In order to describe these phase transition flows, a two-fluid two-pressure approach is considered. This description of the liquid-vapor mixing is associated to the seven-equation model introduced by Baer and Nunziato. This work investigates the properties of this model in order to simulate the phase transition flows occurring in nuclear engineering. First, a theoretical thermodynamic framework is constructed to describe the liquid-vapor mixing. Provided with this framework, various modelling choices are suggested for the interaction terms between the phases. These closure laws comply with an entropy inequality. The mathematical properties of this model are thereafter examined. The convective part is associated to a nonconservative hyperbolic system. First, we focus on the definition of its weak solutions. Several flow regimes for the two-phase mixing derive from this analysis. Such regimes for the two-phase flows are analogous to the torrential and fluvial regimes for the shallow-water equations. Furthermore, we establish the linear and nonlinear stabilities of the liquid-vapor equilibrium. Finally, the implementation of a turbulence model and the introduction of a reconstruction process for the interfacial area are investigated in order to refine the description of the interfacial transfers. Using a fractional step approach, a Finite Volume method is at last constructed to simulate this model. First, various nonconservative adaptations of standard Riemann solvers are developed to approach the convective part. Unlike the classic nonconservative framework, these schemes converge towards the same solution. Furthermore, a new relaxation scheme is proposed to approach the interfacial transfers. Provided with these schemes, the whole numerical method preserves the liquid-vapor equilibria. Using this numerical method, a careful comparison between the one- and two-pressure two

Full closure strategic analysis.

Science.gov (United States)

2014-07-01

The full closure strategic analysis was conducted to create a decision process whereby full roadway : closures for construction and maintenance activities can be evaluated and approved or denied by CDOT : Traffic personnel. The study reviewed current...

Crack closure, a literature study

Science.gov (United States)

Holmgren, M.

1993-08-01

In this report crack closure is treated. The state of the art is reviewed. Different empirical formulas for determining the crack closure are compared with each other, and their benefits are discussed. Experimental techniques for determining the crack closure stress are discussed, and some results from fatigue tests are also reported. Experimental data from the literature are reported.

A numerical spectral approach to solve the dislocation density transport equation

International Nuclear Information System (INIS)

Djaka, K S; Taupin, V; Berbenni, S; Fressengeas, C

2015-01-01

A numerical spectral approach is developed to solve in a fast, stable and accurate fashion, the quasi-linear hyperbolic transport equation governing the spatio-temporal evolution of the dislocation density tensor in the mechanics of dislocation fields. The approach relies on using the Fast Fourier Transform algorithm. Low-pass spectral filters are employed to control both the high frequency Gibbs oscillations inherent to the Fourier method and the fast-growing numerical instabilities resulting from the hyperbolic nature of the transport equation. The numerical scheme is validated by comparison with an exact solution in the 1D case corresponding to dislocation dipole annihilation. The expansion and annihilation of dislocation loops in 2D and 3D settings are also produced and compared with finite element approximations. The spectral solutions are shown to be stable, more accurate for low Courant numbers and much less computation time-consuming than the finite element technique based on an explicit Galerkin-least squares scheme. (paper)

Scalp Wound Closure with K wires: An alternative easier method to scalp wound closure.

Science.gov (United States)

Ramesh, S; Ajik, S

2012-12-01

Scalp defects and lacerations present a reconstructive challenge to plastic surgeons. Many methods have been described from the use of skin grafting to rotation flaps. Here we present a method of closure of a contaminated scalp wound with the use of Kirschner wires. In our case, closure of scalp laceration was made possible with the use of 1.4 Kirschner wires and cable tie/ zip tie fasteners. The duration to closure of wound was 10 days. In reconstructing the scalp defect, this method was found to adhere to principles of scalp reconstruction. There were no post operative complications found from the procedure. On initial application on the edge of the wound, tension applied caused the K wires to cut through the wound edge. On replacement of K wires 1cm away from wound edge the procedure was not plagued by any further complication. In conclusion we find scalp closure with Kirschner wires are a simple and effective method for scalp wound closure.

Revisit to Grad's Closure and Development of Physically Motivated Closure for Phenomenological High-Order Moment Model

International Nuclear Information System (INIS)

Myong, R. S.; Nagdewe, S. P.

2011-01-01

The Grad's closure for the high-order moment equation is revisited and, by extending his theory, a physically motivated closure is developed for the one-dimensional velocity shear gas flow. The closure is based on the physical argument of the relative importance of various terms appearing in the moment equation. Also, the closure is derived such that the resulting theory may be inclusive of the well established linear theory (Navier-Stokes-Fourier) as limiting case near local thermal equilibrium.

Soft timing closure for soft programmable logic cores: The ARGen approach

OpenAIRE

Bollengier , Théotime; Lagadec , Loïc; Najem , Mohamad; Le Lann , Jean-Christophe; Guilloux , Pierre

2017-01-01

International audience; Reconfigurable cores support post-release updates which shortens time-to-market while extending circuits’ lifespan. Reconfigurable cores can be provided as hard cores (ASIC) or soft cores (RTL). Soft reconfigurable cores outperform hard reconfigurable cores by preserving the ASIC synthesis flow, at the cost of lowering scalability but also exacerbating timing closure issues. This article tackles these two issues and introduces the ARGen generator that produces scalable...

Assessment of a simplified set of momentum closure relations for low volume fraction regimes in STAR-CCM+ and OpenFOAM

International Nuclear Information System (INIS)

Sugrue, Rosemary; Magolan, Ben; Lubchenko, Nazar; Baglietto, Emilio

2017-01-01

Highlights: •A simplified set of momentum closures – Bubbly And Moderate void Fraction (BAMF) – is proposed. •BAMF model is assessed by simulation of 12 cases from the Liu and Bankoff experimental database. •Portability between STAR-CCM+ and OpenFOAM CFD softwares is demonstrated. •Both CFD softwares yield mean flow predictions in close agreement with experimental results. -- Abstract: Multiphase computational fluid dynamics (M-CFD) modeling approaches provide three-dimensional resolution of complex two-phase flow and boiling heat transfer phenomena, which makes them an invaluable tool for nuclear reactor design applications. By virtue of the Eulerian-Eulerian spatial and temporal averaging framework, additional terms manifest in the phase momentum equations that require closure through prescription of interfacial forces in the stream-wise and lateral flow directions, as well as in the near-wall region. These momentum closures are critical to M-CFD prediction of mean flow profiles, including velocity and volume fraction distributions, and yet while an overwhelming number of them has been developed, no consensus exists on how to assemble them to achieve a simplified set of closures that is numerically robust and extensible to a wide array of flow configurations; further, no consistent demonstration has been shown of the cross-code portability of these closures between CFD softwares. To address these challenges, we propose in this work a simplified set of momentum closures for stream-wise drag and lateral redistribution mechanisms—collectively referred to as the Bubbly And Moderate void Fraction (BAMF) model—and assess its performance by simulation of 12 cases from the Liu and Bankoff experimental database using STAR-CCM+ and OpenFOAM. Both CFD softwares yield mean flow predictions that are in close agreement with the experimental results, and also in close agreement with each other. These results confirm the effectiveness of the BAMF model and its

Building bridges connections and challenges in modern approaches to numerical partial differential equations

CERN Document Server

Brezzi, Franco; Cangiani, Andrea; Georgoulis, Emmanuil

2016-01-01

This volume contains contributed survey papers from the main speakers at the LMS/EPSRC Symposium “Building bridges: connections and challenges in modern approaches to numerical partial differential equations”. This meeting took place in July 8-16, 2014, and its main purpose was to gather specialists in emerging areas of numerical PDEs, and explore the connections between the different approaches. The type of contributions ranges from the theoretical foundations of these new techniques, to the applications of them, to new general frameworks and unified approaches that can cover one, or more than one, of these emerging techniques.

Comparison of numerical approaches to solve a Poincare-covariant Faddeev equation

International Nuclear Information System (INIS)

Alkofer, R.; Eichmann, G.; Krassnigg, A.; Schwinzerl, M.

2006-01-01

Full text: The quark core of Baryons can be described with the help of the numerical solution of the Poincare-Faddeev equation. Hereby the used elements, as e.g. the quark propagator are taken from non-perturbative studies of Landau gauge QCD. Different numerical approaches to solve in this way the relativistic three quark problem are compared and benchmarked results for the efficiency of different algorithms are presented. (author)

A mapping closure for turbulent scalar mixing using a time-evolving reference field

Science.gov (United States)

Girimaji, Sharath S.

1992-01-01

A general mapping-closure approach for modeling scalar mixing in homogeneous turbulence is developed. This approach is different from the previous methods in that the reference field also evolves according to the same equations as the physical scalar field. The use of a time-evolving Gaussian reference field results in a model that is similar to the mapping closure model of Pope (1991), which is based on the methodology of Chen et al. (1989). Both models yield identical relationships between the scalar variance and higher-order moments, which are in good agreement with heat conduction simulation data and can be consistent with any type of epsilon(phi) evolution. The present methodology can be extended to any reference field whose behavior is known. The possibility of a beta-pdf reference field is explored. The shortcomings of the mapping closure methods are discussed, and the limit at which the mapping becomes invalid is identified.

Variability of orogenic magmatism during Mediterranean-style continental collisions : A numerical modelling approach

NARCIS (Netherlands)

Andrić, N.; Vogt, K.; Matenco, L.; Cvetković, V.; Cloetingh, S.; Gerya, T.

The relationship between magma generation and the tectonic evolution of orogens during subduction and subsequent collision requires self-consistent numerical modelling approaches predicting volumes and compositions of the produced magmatic rocks. Here, we use a 2D magmatic-thermomechanical numerical

Nevada Test Site closure program

International Nuclear Information System (INIS)

Shenk, D.P.

1994-08-01

This report is a summary of the history, design and development, procurement, fabrication, installation and operation of the closures used as containment devices on underground nuclear tests at the Nevada Test Site. It also addresses the closure program mothball and start-up procedures. The Closure Program Document Index and equipment inventories, included as appendices, serve as location directories for future document reference and equipment use

Evaluation of a novel trocar-site closure and comparison with a standard Carter-Thomason closure device.

Science.gov (United States)

del Junco, Michael; Okhunov, Zhamshid; Juncal, Samuel; Yoon, Renai; Landman, Jaime

2014-07-01

The aim of this study was to evaluate and compare a novel trocars-site closure device, the WECK EFx™ Endo Fascial Closure System (EFx) with the Carter-Thomason CloseSure System® (CT) for the closure of laparoscopic trocar site defects created by a 12-mm dilating trocar. We created standardized laparoscopic trocars-site abdominal wall defects in cadaver models using a standard 12-mm laparoscopic dilating trocar. Trocar defects were closed in a randomized fashion using one of the two closure systems. We recorded time and number of attempts needed for complete defect closure. In addition, we recorded the ability to maintain pneumoperitoneum, endoscopic visualization, safety, security, and facility based on the surgeon's subjective evaluations. We compared outcomes for the EFx and CT closure systems. We created 72 standardized laparoscopic trocars-site abdominal wall defects. The mean time needed for complete defect closure was 98.53 seconds (±28.9) for the EFx compared with 133.61 seconds (±54.61) for the CT (Psafety were 2.92 for EFx vs 2.19 for CT (Pvs 1.83 for EFx and CT, respectively (Pvs 2.33 for CT (P=0.022). No significant difference was observed between the EFx and the CT systems for endoscopic visualization (2.28 vs 2.50, P=0.080). In this in vitro cadaver trial, the EFx was superior in terms of time needed to complete defect closure, safety, and facility. CT was superior in terms of maintenance of pneumoperitoneum. Both systems were equal in the number of attempts needed to complete the defect closure and endoscopic visualization.

Local-scale modelling of density-driven flow for the phases of repository operation and post-closure at Beberg

International Nuclear Information System (INIS)

Jaquet, O.; Siegel, P.

2004-09-01

repository during the operational phase. Scoping calculations have shown that the results could be improved by applying free-surface boundary conditions when modelling the impact of the repository. Modelling density-driven flow at local scale with a repository under atmospheric pressure conditions is feasible using CONNECTFLOW/NAMMU. Such non-linear problems are intrinsically difficult to solve and linked with numerical difficulties. In particular, we could overcome the numerous convergence issues but it was demanding in terms of computing performance. Concerning pre-processing, this study has allowed us to improve the integration of CONNECTFLOW/NAMMU within Colenco's computing environment. It is especially noteworthy that numerical calculations with complex geometries (e.g. repository layout with tunnels) have become possible. During the phases of repository operation and post-closure, near-surface effects are likely to occur. The evaluation of their environmental impacts needs to be performed using a numerical model with specific boundary conditions (free surface type). The following recommendations are proposed regarding additional work and open issues: Assessment of the environmental impacts in relation to the phases of repository operation and post-closure. Evaluation of repository impact using a more detailed geometry for the repository layout, such as introducing the shafts and access tunnels as well as including skin effect around the tunnels. Determination of repository impact by modelling density-driven flow including the rock matrix diffusion of salt. The approach for modelling repository impact at Beberg has successfully described the assumed conditions and relevant processes. It may certainly serve as a well founded base for future modelling tasks to provide solutions to further questions

Results of Washington's phase two study on closure requirements for the Hanford commercial low-level waste facility

International Nuclear Information System (INIS)

Anderson, D.C.; Hana, S.L.

1989-01-01

This paper reports on the closure design objectives and cover alternatives resulting from the state of Washington's phase two study on closure and long-term care for the Hanford commercial low-level radioactive waste disposal facility. Four approaches to dealing with subsidence and two cover design alternatives are discussed in this paper, along with information on each layer of each cover. Objectives for closure of the Hanford low-level waste facility are also discussed

Numerical optimization of die geometry in open die forging

DEFF Research Database (Denmark)

Christiansen, Peter; Hattel, Jesper Henri; Bay, Niels

2013-01-01

This paper deals with numerical optimization of open die forging of large metallic ingots made by casting implying risk of defects, e.g. central pores. Different material hardening properties and die geometries are combined in order to investigate, which geometry gives rise to maximum closure...

Eyelid closure at death

Directory of Open Access Journals (Sweden)

A D Macleod

2009-01-01

Full Text Available Aim: To observe the incidence of full or partial eyelid closure at death. Materials and Methods: The presence of ptosis was recorded in 100 consecutive hospice patient deaths. Results: Majority (63% of the patients died with their eyes fully closed, however, 37% had bilateral ptosis at death, with incomplete eye closure. In this study, central nervous system tumor involvement and/or acute hepatic encephalopathy appeared to be pre-mortem risk factors of bilateral ptosis at death. Conclusion: Organicity and not psychogenicity is, therefore, the likely etiology of failure of full eyelid closure at death.

Closure and Sealing Design Calculation

International Nuclear Information System (INIS)

T. Lahnalampi; J. Case

2005-01-01

The purpose of the ''Closure and Sealing Design Calculation'' is to illustrate closure and sealing methods for sealing shafts, ramps, and identify boreholes that require sealing in order to limit the potential of water infiltration. In addition, this calculation will provide a description of the magma that can reduce the consequences of an igneous event intersecting the repository. This calculation will also include a listing of the project requirements related to closure and sealing. The scope of this calculation is to: summarize applicable project requirements and codes relating to backfilling nonemplacement openings, removal of uncommitted materials from the subsurface, installation of drip shields, and erecting monuments; compile an inventory of boreholes that are found in the area of the subsurface repository; describe the magma bulkhead feature and location; and include figures for the proposed shaft and ramp seals. The objective of this calculation is to: categorize the boreholes for sealing by depth and proximity to the subsurface repository; develop drawing figures which show the location and geometry for the magma bulkhead; include the shaft seal figures and a proposed construction sequence; and include the ramp seal figure and a proposed construction sequence. The intent of this closure and sealing calculation is to support the License Application by providing a description of the closure and sealing methods for the Safety Analysis Report. The closure and sealing calculation will also provide input for Post Closure Activities by describing the location of the magma bulkhead. This calculation is limited to describing the final configuration of the sealing and backfill systems for the underground area. The methods and procedures used to place the backfill and remove uncommitted materials (such as concrete) from the repository and detailed design of the magma bulkhead will be the subject of separate analyses or calculations. Post-closure monitoring will not

Scope and closures

CERN Document Server

Simpson, Kyle

2014-01-01

No matter how much experience you have with JavaScript, odds are you don’t fully understand the language. This concise yet in-depth guide takes you inside scope and closures, two core concepts you need to know to become a more efficient and effective JavaScript programmer. You’ll learn how and why they work, and how an understanding of closures can be a powerful part of your development skillset.

Post-closure Safety of the Borehole Disposal Concept

International Nuclear Information System (INIS)

Little, R.

2016-01-01

Conclusion: • BDC post-closure safety assessments have been undertaken over last 15-20 years. • Consistent with best international practice and IAEA guidance: – used structure assessment approach; – peer reviewed; – iterative. • Built confidence in BDC as a safe long-term management option for DSRSs at both a generic and site-specific level

Evaluation of ecological consequences of coal mine closure in Kuzbass coal region

International Nuclear Information System (INIS)

Schastlivcev, E.L.; Barannic, L.P.; Ovdenko, B.I.; Bykov, A.A.

2000-01-01

Kemerovo region (otherwise called Kuzbass) is the most industrially developed and urbanized region of Siberia, Russia. The main industrial branch of Kuzbass is coal output. Open pits and underground mines of Kuzbass produce about 40% of total amount of coal in Russia and more than 70% of coking coal. In the current process of the coal industry's restructuring, the closing of many unprofitable coal enterprises is associated with radical changes in their influence on the environment. The task to provide a probable forecast of ecological consequence of mine closure is both practically significant and complicated. In order to find some scientific approach to solve named problem the authors made in the paper the first attempts to analyze of accessible closed mines data in Kuzbass, to classify coal mines (working and closed) with respect to there negative influence on soil, water and atmosphere and to obtain some numerical estimates of possible bounds of this influence. 7 refs

Estimation of flushing time in a monsoonal estuary using observational and numerical approaches

Digital Repository Service at National Institute of Oceanography (India)

Manoj, N.T.

and numerical model simulations to correlate TF with monthly mean river discharges. The power regression equation derived from FOS (numerical model) showed good statistical fit with data (r=-0.997 (-1.0)) for any given river discharge compared... was to calculate the TF in the Mandovi during three different seasons in a year. For this purpose, we adopted two approaches, first the computation of TF from FOS. The application of H2N-Model was another approach to calculate the TF in the estuary. The FWF...

Direct numerical simulation of natural convection in a vertical channel: a tool for second moment closure modeling

International Nuclear Information System (INIS)

Maupu, V.; Laurence, D.

1996-01-01

Natural turbulent convection in a differentially heated infinite vertical slot is computed with a mixed finite differences/Fourier code. At a Rayleigh number of 10 5 , in the case without mean stratification, periodic perturbations from the laminar solution develop and transition to a fully turbulent flow occurs. From then on, a database of one-point statistics is presented: mean velocity and temperature, Reynolds stress components, turbulent heat fluxes and variance of temperature, but also budgets of second moment equations. This database is then used for testing of a second moment closure based on the Launder-Reece-Rodi model on an elliptic relaxation for near wall effects on pressure redistribution. This level of modelling is required by the presence of counter gradient fluxes, which cannot be accounted for eddy viscosity and eddy diffusivity assumptions. Furthermore, an algebraic third order moment closure was found necessary because of counter gradient turbulent transport terms which appear to mainly originate from the mean velocity and temperature gradient terms usually neglected in conventional transport models, such as the standard Daly-Harlow or Hanjalic-Launder models. (authors)

100-D Ponds closure plan. Revision 1

International Nuclear Information System (INIS)

Petersen, S.W.

1997-09-01

The 100-D Ponds is a Treatment, Storage, and Disposal (TSD) unit on the Hanford Facility that received both dangerous and nonregulated waste. This Closure Plan (Rev. 1) for the 100-D Ponds TSD unit consists of a RCRA Part A Dangerous Waste Permit Application (Rev. 3), a RCRA Closure Plan, and supporting information contained in the appendices to the plan. The closure plan consists of eight chapters containing facility description, process information, waste characteristics, and groundwater monitoring data. There are also chapters containing the closure strategy and performance standards. The strategy for the closure of the 100-D Ponds TSD unit is clean closure. Appendices A and B of the closure plan demonstrate that soil and groundwater beneath 100-D Ponds are below cleanup limits. All dangerous wastes or dangerous waste constituents or residues associated with the operation of the ponds have been removed, therefore, human health and the environment are protected. Discharges to the 100-D Ponds, which are located in the 100-DR-1 operable unit, were discontinued in June 1994. Contaminated sediment was removed from the ponds in August 1996. Subsequent sampling and analysis demonstrated that there is no contamination remaining in the ponds, therefore, this closure plan is a demonstration of clean closure

Closure for spent-fuel transport and storage containers

International Nuclear Information System (INIS)

Ahner, S.; Knackstedt, H.G.; Srostlik, P.

1980-01-01

The container has a transport closure and a shielding closure. This shielding closure consists of two pieces (double closure system), which can be fartened to one another like a bayonet fixing. A central motion of rotation is enough to open the closure. It can be done remote-controlled as well as manually. (DG) [de

Superresolving Black Hole Images with Full-Closure Sparse Modeling

Science.gov (United States)

Crowley, Chelsea; Akiyama, Kazunori; Fish, Vincent

2018-01-01

It is believed that almost all galaxies have black holes at their centers. Imaging a black hole is a primary objective to answer scientific questions relating to relativistic accretion and jet formation. The Event Horizon Telescope (EHT) is set to capture images of two nearby black holes, Sagittarius A* at the center of the Milky Way galaxy roughly 26,000 light years away and the other M87 which is in Virgo A, a large elliptical galaxy that is 50 million light years away. Sparse imaging techniques have shown great promise for reconstructing high-fidelity superresolved images of black holes from simulated data. Previous work has included the effects of atmospheric phase errors and thermal noise, but not systematic amplitude errors that arise due to miscalibration. We explore a full-closure imaging technique with sparse modeling that uses closure amplitudes and closure phases to improve the imaging process. This new technique can successfully handle data with systematic amplitude errors. Applying our technique to synthetic EHT data of M87, we find that full-closure sparse modeling can reconstruct images better than traditional methods and recover key structural information on the source, such as the shape and size of the predicted photon ring. These results suggest that our new approach will provide superior imaging performance for data from the EHT and other interferometric arrays.

Echocardiographic predictors of coil vs device closure in patients undergoing percutaneous patent ductus arteriosus closure.

Science.gov (United States)

Roushdy, Alaa; Abd El Razek, Yasmeen; Mamdouh Tawfik, Ahmed

2018-01-01

To determine anatomic and hemodynamic echocardiographic predictors for patent ductus arteriosus (PDA) device vs coil closure. Seventy-six patients who were referred for elective transcatheter PDA closure were enrolled in the study. All patients underwent full echocardiogram including measurement of the PDA pulmonary end diameter, color flow width and extent, peak and end-diastolic Doppler gradients across the duct, diastolic flow reversal, left atrial dimensions and volume, left ventricular sphericity index, and volumes. The study group was subdivided into 2 subgroups based on the mode of PDA closure whether by coil (n = 42) or device (n = 34). Using univariate analysis there was a highly significant difference between the 2 groups as regard the pulmonary end diameter measured in both the suprasternal and parasternal short-axis views as well as the color flow width and color flow extent (P closure group had statistically significant higher end-systolic and end-diastolic volumes indexed, left atrial volume, and diastolic flow reversal. Receiver operating characteristic curve analysis showed a pulmonary end diameter cutoff point from the suprasternal view > 2.5 mm and from parasternal short-axis view > 2.61 mm to have the highest balanced sensitivity and specificity to predict the likelihood for device closure (AUC 0.971 and 0.979 respectively). The pulmonary end diameter measured from the suprasternal view was the most independent predictor of device closure. The selection between PDA coil or device closure can be done on the basis of multiple anatomic and hemodynamic echocardiographic variables. © 2017 Wiley Periodicals, Inc.

CRITICAL ASSUMPTIONS IN THE F-TANK FARM CLOSURE OPERATIONAL DOCUMENTATION REGARDING WASTE TANK INTERNAL CONFIGURATIONS

Energy Technology Data Exchange (ETDEWEB)

Hommel, S.; Fountain, D.

2012-03-28

The intent of this document is to provide clarification of critical assumptions regarding the internal configurations of liquid waste tanks at operational closure, with respect to F-Tank Farm (FTF) closure documentation. For the purposes of this document, FTF closure documentation includes: (1) Performance Assessment for the F-Tank Farm at the Savannah River Site (hereafter referred to as the FTF PA) (SRS-REG-2007-00002), (2) Basis for Section 3116 Determination for Closure of F-Tank Farm at the Savannah River Site (DOE/SRS-WD-2012-001), (3) Tier 1 Closure Plan for the F-Area Waste Tank Systems at the Savannah River Site (SRR-CWDA-2010-00147), (4) F-Tank Farm Tanks 18 and 19 DOE Manual 435.1-1 Tier 2 Closure Plan Savannah River Site (SRR-CWDA-2011-00015), (5) Industrial Wastewater Closure Module for the Liquid Waste Tanks 18 and 19 (SRRCWDA-2010-00003), and (6) Tank 18/Tank 19 Special Analysis for the Performance Assessment for the F-Tank Farm at the Savannah River Site (hereafter referred to as the Tank 18/Tank 19 Special Analysis) (SRR-CWDA-2010-00124). Note that the first three FTF closure documents listed apply to the entire FTF, whereas the last three FTF closure documents listed are specific to Tanks 18 and 19. These two waste tanks are expected to be the first two tanks to be grouted and operationally closed under the current suite of FTF closure documents and many of the assumptions and approaches that apply to these two tanks are also applicable to the other FTF waste tanks and operational closure processes.

Preface of "The Second Symposium on Border Zones Between Experimental and Numerical Application Including Solution Approaches By Extensions of Standard Numerical Methods"

Science.gov (United States)

Ortleb, Sigrun; Seidel, Christian

2017-07-01

In this second symposium at the limits of experimental and numerical methods, recent research is presented on practically relevant problems. Presentations discuss experimental investigation as well as numerical methods with a strong focus on application. In addition, problems are identified which require a hybrid experimental-numerical approach. Topics include fast explicit diffusion applied to a geothermal energy storage tank, noise in experimental measurements of electrical quantities, thermal fluid structure interaction, tensegrity structures, experimental and numerical methods for Chladni figures, optimized construction of hydroelectric power stations, experimental and numerical limits in the investigation of rain-wind induced vibrations as well as the application of exponential integrators in a domain-based IMEX setting.

Tools for Closure Project and Contract Management: Development of the Rocky Flats Integrated Closure Project Baseline

International Nuclear Information System (INIS)

Gelles, C. M.; Sheppard, F. R.

2002-01-01

This paper details the development of the Rocky Flats Integrated Closure Project Baseline - an innovative project management effort undertaken to ensure proactive management of the Rocky Flats Closure Contract in support of the Department's goal for achieving the safe closure of the Rocky Flats Environmental Technology Site (RFETS) in December 2006. The accelerated closure of RFETS is one of the most prominent projects within the Department of Energy (DOE) Environmental Management program. As the first major former weapons plant to be remediated and closed, it is a first-of-kind effort requiring the resolution of multiple complex technical and institutional challenges. Most significantly, the closure of RFETS is dependent upon the shipment of all special nuclear material and wastes to other DOE sites. The Department is actively working to strengthen project management across programs, and there is increasing external interest in this progress. The development of the Rocky Flats Integrated Closure Project Baseline represents a groundbreaking and cooperative effort to formalize the management of such a complex project across multiple sites and organizations. It is original in both scope and process, however it provides a useful precedent for the other ongoing project management efforts within the Environmental Management program

Implementing a Flipped Classroom Approach in a University Numerical Methods Mathematics Course

Science.gov (United States)

Johnston, Barbara M.

2017-01-01

This paper describes and analyses the implementation of a "flipped classroom" approach, in an undergraduate mathematics course on numerical methods. The approach replaced all the lecture contents by instructor-made videos and was implemented in the consecutive years 2014 and 2015. The sequential case study presented here begins with an…

50 CFR 648.161 - Closures.

Science.gov (United States)

2010-10-01

... Bluefish Fishery § 648.161 Closures. (a) EEZ closure. NMFS shall close the EEZ to fishing for bluefish by... dealer permit holders that no commercial quota is available for landing bluefish in that state. ...

Numeric simulations of en-masse space closure with sliding mechanics.

Science.gov (United States)

Kojima, Yukio; Fukui, Hisao

2010-12-01

En-masse sliding mechanics have been typically used for space closure. Because of friction created at the bracket-wire interface, the force system during tooth movement has not been clarified. Long-term tooth movements in en-masse sliding mechanics were simulated with the finite element method. Tipping of the anterior teeth occurred immediately after application of retraction forces. The force system then changed so that the teeth moved almost bodily, and friction occurred at the bracket-wire interface. Net force transferred to the anterior teeth was approximately one fourth of the applied force. The amount of the mesial force acting on the posterior teeth was the same as that acting on the anterior teeth. Irrespective of the amount of friction, the ratio of movement distances between the posterior and anterior teeth was almost the same. By increasing the applied force or decreasing the frictional coefficient, the teeth moved rapidly, but the tipping angle of the anterior teeth increased because of the elastic deflection of the archwire. Finite element simulation clarified the tooth movement and the force system in en-masse sliding mechanics. Long-term tooth movement could not be predicted from the initial force system. The friction was not detrimental to the anchorage. Increasing the applied force or decreasing the friction for rapid tooth movement might result in tipping of the teeth. Copyright © 2010 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Conceptual Model and Numerical Approaches for Unsaturated Zone Flow and Transport

International Nuclear Information System (INIS)

H.H. Liu

2004-01-01

The purpose of this model report is to document the conceptual and numerical models used for modeling unsaturated zone (UZ) fluid (water and air) flow and solute transport processes. This work was planned in ''Technical Work Plan for: Unsaturated Zone Flow Model and Analysis Report Integration'' (BSC 2004 [DIRS 169654], Sections 1.2.5, 2.1.1, 2.1.2 and 2.2.1). The conceptual and numerical modeling approaches described in this report are mainly used for models of UZ flow and transport in fractured, unsaturated rock under ambient conditions. Developments of these models are documented in the following model reports: (1) UZ Flow Model and Submodels; (2) Radionuclide Transport Models under Ambient Conditions. Conceptual models for flow and transport in unsaturated, fractured media are discussed in terms of their applicability to the UZ at Yucca Mountain. The rationale for selecting the conceptual models used for modeling of UZ flow and transport is documented. Numerical approaches for incorporating these conceptual models are evaluated in terms of their representation of the selected conceptual models and computational efficiency; and the rationales for selecting the numerical approaches used for modeling of UZ flow and transport are discussed. This report also documents activities to validate the active fracture model (AFM) based on experimental observations and theoretical developments. The AFM is a conceptual model that describes the fracture-matrix interaction in the UZ of Yucca Mountain. These validation activities are documented in Section 7 of this report regarding use of an independent line of evidence to provide additional confidence in the use of the AFM in the UZ models. The AFM has been used in UZ flow and transport models under both ambient and thermally disturbed conditions. Developments of these models are documented

3718-F Alkali Metal Treatment and Storage Facility Closure Plan. Revision 1

Energy Technology Data Exchange (ETDEWEB)

None

1992-11-01

The Hanford Site, located northwest of the city of Richland, Washington, houses reactors, chemical-separation systems, and related facilities used for the production of special nuclear materials, as well as for activities associated with nuclear energy development. The 300 Area of the Hanford Site contains reactor fuel manufacturing facilities and several research and development laboratories. The 3718-F Alkali Metal Treatment and Storage Facility (3718-F Facility), located in the 300 Area, was used to store and treat alkali metal wastes. Therefore, it is subject to the regulatory requirements for the storage and treatment of dangerous wastes. Closure will be conducted pursuant to the requirements of the Washington Administrative Code (WAC) 173-303-610 (Ecology 1989) and 40 CFR 270.1. Closure also will satisfy the thermal treatment facility closure requirements of 40 CFR 265.381. This closure plan presents a description of the 3718-F Facility, the history of wastes managed, and the approach that will be followed to close the facility. Only hazardous constituents derived from 3718-F Facility operations will be addressed.

Comparison of fasciotomy wound closures using traditional dressing changes and the vacuum-assisted closure device.

Science.gov (United States)

Zannis, John; Angobaldo, Jeff; Marks, Malcolm; DeFranzo, Anthony; David, Lisa; Molnar, Joseph; Argenta, Louis

2009-04-01

Fasciotomy wounds can be a major contributor to length of stay for patients as well as a difficult reconstructive challenge. Once the compartment pressure has been relieved and stabilized, the wound should be closed as quickly and early as possible to avoid later complications. Skin grafting can lead to morbidity and scarring at both the donor and fasciotomy site. Primary closure results in a more functional and esthetic outcome with less morbidity for the patient, but can often be difficult to achieve secondary to edema, skin retraction, and skin edge necrosis. Our objective was to examine fasciotomy wound outcomes, including time to definitive closure, comparing traditional wet-to-dry dressings, and the vacuum-assisted closure (VAC) device. This retrospective chart review included a consecutive series of patients over a 10-year period. This series included 458 patients who underwent 804 fasciotomies. Of these fasciotomy wounds, 438 received exclusively VAC. dressings, 270 received only normal saline wet-to-dry dressings, and 96 were treated with a combination of both. Of the sample, 408 patients were treated with exclusively VAC therapy or wet-to-dry dressings and 50 patients were treated with a combination of both. In comparing all wounds, there was a statistically significant higher rate of primary closure using the VAC versus traditional wet-to-dry dressings (P lower extremities and P extremities). The time to primary closure of wounds was shorter in the VAC. group in comparison with the non-VAC group. This study has shown that the use of the VAC for fasciotomy wound closure results in a higher rate of primary closure versus traditional wet-to-dry dressings. In addition, the time to primary closure of wounds or time to skin grafting is shorter when the VAC was employed. The VAC used in the described settings decreases hospitalization time, allows for earlier rehabilitation, and ultimately leads to increased patient satisfaction.

Predictions of flow and heat transfer in multiple impinging jets with an elliptic-blending second-moment closure

NARCIS (Netherlands)

Thielen, L.; Hanjalić, K.; Jonker, H.; Manceau, R.

2005-01-01

We present numerical computations of flow and heat transfer in multiple jets impinging normally on a flat heated surface, obtained with a new second-moment turbulence closure combined with an elliptic blending model of non-viscous wall blocking effect. This model provides the mean velocity and

Use of PTFE patch for pericardial closure after minimal invasive LVAD implantation.

Science.gov (United States)

Mohite, Prashant N; Sabashnikov, Anton; Popov, Aron F; Fatullayev, Javid; Simon, André R

2016-07-01

The left ventricular assist device (LVAD) is now a routine therapy for advanced heart failure. The thoracotomy approach for LVAD implantation, in which the left ventricle is approached through a pericardial rent, is becoming popular. We demonstrate closure of the pericardial rent with a polytetrafluoroethylene (PTFE) patch and its advantages. © The Author(s) 2015.

32 CFR 989.25 - Base closure and realignment.

Science.gov (United States)

2010-07-01

... 32 National Defense 6 2010-07-01 2010-07-01 false Base closure and realignment. 989.25 Section 989... PROTECTION ENVIRONMENTAL IMPACT ANALYSIS PROCESS (EIAP) § 989.25 Base closure and realignment. Base closure or realignment may entail special requirements for environmental analysis. The permanent base closure...

Patent ductus arteriosus closure using an Amplatzer™ ventricular septal defect closure device

Science.gov (United States)

Fernando, Rajeev; Koranne, Ketan; Loyalka, Pranav; Kar, Biswajit; Gregoric, Igor

2013-01-01

The ductus arteriosus originates from the persistence of the distal portion of the left sixth aortic arch. It connects the descending aorta (immediately distal to the left subclavian artery) to the roof of the main pulmonary artery, near the origin of the left pulmonary artery. Persistence of the duct beyond 48 h after birth is abnormal and results in patent ductus arteriosus (PDA). PDA is rare in adults because it is usually discovered and treated in childhood. Mechanical closure remains the definitive therapy because the patency of ductus arteriosus may lead to multiple complications, depending on the size and flow through the ductus. PDA closure is indicated in patients with symptoms and evidence of left heart enlargement, and in patients with elevated pulmonary pressures when reversal is possible. Transcatheter closure is the preferred technique in adults because it avoids sternotomy, reduces the length of hospital stay and is associated with fewer complications compared with surgery. First demonstrated in 1967, both the technique and the occluder devices used have since evolved. However, designing an ideal PDA occluder has been a challenge due to the variability in size, shape and orientation of PDAs. The present article describes a case involving a 35-year-old woman who presented to the Center for Advanced Heart Failure (Houston, USA) with congestive heart failure due to a large PDA, which was successfully occluded using an Amplatzer (St Jude Medical, USA) muscular ventricular septal defect closure device. The wider waist and dual-retention discs of these ventricular septal defect closure devices may be important factors to consider in the future development of devices for the occlusion of large PDAs. PMID:24294051

Post-closure resaturation of a deep radioactive waste repository

International Nuclear Information System (INIS)

Cox, I.C.S.; Rodwell, W.R.

1989-03-01

The post-closure resaturation of a deep radioactive waste repository has been modelled for a number of generic disposal concepts. A combination of numerical ground water flow simulations and analytical calculations has been used to investigate the variation of repository fluid pressure and degree of water saturation with time, and to determine the factors influencing resaturation times. The host rock permeability was found to be the most important determining factor. For geological environments regarded as likely for a waste repository, resaturation is predicted to be a short term process compared with gas generation and contaminant migration timescales. (author)

Evaluation of the Momentum Closure Schemes in MPAS-Ocean

Science.gov (United States)

Zhao, Shimei; Liu, Yudi; Liu, Wei

2018-04-01

In order to compare and evaluate the performances of the Laplacian viscosity closure, the biharmonic viscosity closure, and the Leith closure momentum schemes in the MPAS-Ocean model, a variety of physical quantities, such as the relative reference potential energy (RPE) change, the RPE time change rate (RPETCR), the grid Reynolds number, the root mean square (RMS) of kinetic energy, and the spectra of kinetic energy and enstrophy, are calculated on the basis of results of a 3D baroclinic periodic channel. Results indicate that: 1) The RPETCR demonstrates a saturation phenomenon in baroclinic eddy tests. The critical grid Reynolds number corresponding to RPETCR saturation differs between the three closures: the largest value is in the biharmonic viscosity closure, followed by that in the Laplacian viscosity closure, and that in the Leith closure is the smallest. 2) All three closures can effectively suppress spurious dianeutral mixing by reducing the grid Reynolds number under sub-saturation conditions of the RPETCR, but they can also damage certain physical processes. Generally, the damage to the rotation process is greater than that to the advection process. 3) The dissipation in the biharmonic viscosity closure is strongly dependent on scales. Most dissipation concentrates on small scales, and the energy of small-scale eddies is often transferred to large-scale kinetic energy. The viscous dissipation in the Laplacian viscosity closure is the strongest on various scales, followed by that in the Leith closure. Note that part of the small-scale kinetic energy is also transferred to large-scale kinetic energy in the Leith closure. 4) The characteristic length scale L and the dimensionless parameter D in the Leith closure are inherently coupled. The RPETCR is inversely proportional to the product of D and L. When the product of D and L is constant, both the simulated RPETCR and the inhibition of spurious dianeutral mixing are the same in all tests using the Leith

Numerical study of dispersing pollutant clouds in a built-up environment

International Nuclear Information System (INIS)

Wang Bingchen; Yee, Eugene; Lien, F.-S.

2009-01-01

In this paper, we study numerically the dispersion of a passive scalar released from an instantaneous point source in a built-up (urban) environment using a Reynolds-averaged Navier-Stokes method. A nonlinear k-ε turbulence model [Speziale, C.G., 1987. On nonlinear k-l and k-ε models of turbulence. J. Fluid Mech., 178, 459-475] was used for the closure of the mean momentum equations. A tensor diffusivity model [Yoshizawa, A., 1985. Statistical analysis of the anisotropy of scalar diffusion in turbulent shear flows. Phys. Fluids, 28, 3226-3231] was used for closure of the scalar transport equations. The concentration variance was also calculated from its transport equation, for which new values of Yoshizawa's closure coefficients are used, in order to account for the instantaneous tracer release and the complex geometry. A new dissipation length-scale model, required for the modelling of the dissipation rate of concentration variance, is also proposed. The numerical results for the flow, the pollutant concentration and the concentration variance, are compared with experimental data. This data was obtained from a water-channel simulation of a full-scale field experiment of tracer dispersion through a large array of building-like obstacles known as the Mock Urban Setting Trial (MUST)

Numerical study of dispersing pollutant clouds in a built-up environment

Energy Technology Data Exchange (ETDEWEB)

Wang Bingchen [Department of Mechanical and Manufacturing Engineering, University of Manitoba, 75A Chancellors Circle, Winnipeg, Manitoba, R3T 5V6 (Canada)], E-mail: bc_wang@umanitoba.ca; Yee, Eugene [Defence Research and Development Canada - Suffield, P.O. Box 4000, STN Main, Medicine Hat, AB, T1A 8K6 (Canada)], E-mail: eugene.yee@drdc-rddc.gc.ca; Lien, F.-S. [Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada)], E-mail: fslien@mecheng1.uwaterloo.ca

2009-02-15

In this paper, we study numerically the dispersion of a passive scalar released from an instantaneous point source in a built-up (urban) environment using a Reynolds-averaged Navier-Stokes method. A nonlinear k-{epsilon} turbulence model [Speziale, C.G., 1987. On nonlinear k-l and k-{epsilon} models of turbulence. J. Fluid Mech., 178, 459-475] was used for the closure of the mean momentum equations. A tensor diffusivity model [Yoshizawa, A., 1985. Statistical analysis of the anisotropy of scalar diffusion in turbulent shear flows. Phys. Fluids, 28, 3226-3231] was used for closure of the scalar transport equations. The concentration variance was also calculated from its transport equation, for which new values of Yoshizawa's closure coefficients are used, in order to account for the instantaneous tracer release and the complex geometry. A new dissipation length-scale model, required for the modelling of the dissipation rate of concentration variance, is also proposed. The numerical results for the flow, the pollutant concentration and the concentration variance, are compared with experimental data. This data was obtained from a water-channel simulation of a full-scale field experiment of tracer dispersion through a large array of building-like obstacles known as the Mock Urban Setting Trial (MUST)

Mathematical properties of numerical inversion for jet calibrations

Energy Technology Data Exchange (ETDEWEB)

Cukierman, Aviv [Physics Department, Stanford University, Stanford, CA 94305 (United States); SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA 94025 (United States); Nachman, Benjamin, E-mail: bnachman@cern.ch [Physics Department, Stanford University, Stanford, CA 94305 (United States); SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA 94025 (United States); Physics Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94704 (United States)

2017-06-21

Numerical inversion is a general detector calibration technique that is independent of the underlying spectrum. This procedure is formalized and important statistical properties are presented, using high energy jets at the Large Hadron Collider as an example setting. In particular, numerical inversion is inherently biased and common approximations to the calibrated jet energy tend to over-estimate the resolution. Analytic approximations to the closure and calibrated resolutions are demonstrated to effectively predict the full forms under realistic conditions. Finally, extensions of numerical inversion are presented which can reduce the inherent biases. These methods will be increasingly important to consider with degraded resolution at low jet energies due to a much higher instantaneous luminosity in the near future.

When the Battle is Lost and Won: Delayed Chest Closure After Bilateral Lung Transplantation.

Science.gov (United States)

Soresi, Simona; Sabashnikov, Anton; Weymann, Alexander; Zeriouh, Mohamed; Simon, André R; Popov, Aron-Frederik

2015-10-12

In this article we summarize benefits of delayed chest closure strategy in lung transplantation, addressing indications, different surgical techniques, and additional perioperative treatment. Delayed chest closure seems to be a valuable and safe strategy in managing patients with various conditions after lung transplantation, such as instable hemodynamics, need for high respiratory pressures, coagulopathy, and size mismatch. Therefore, this approach should be considered in lung transplant centers to give patients time to recover before the chest is closed.

Analysis of the flamelet concept in the numerical simulation of laminar partially premixed flames

Energy Technology Data Exchange (ETDEWEB)

Consul, R.; Oliva, A.; Perez-Segarra, C.D.; Carbonell, D. [Centre Tecnologic de Transferencia de Calor (CTTC), Universitat Politecnica de Catalunya (UPC), Colom 11, E-08222, Terrassa, Barcelona (Spain); de Goey, L.P.H. [Eindhoven University of Technology, Department of Mechanical Engineering, P.O. Box 513, 5600 MB Eindhoven (Netherlands)

2008-04-15

The aim of this work is to analyze the application of flamelet models based on the mixture fraction variable and its dissipation rate to the numerical simulation of partially premixed flames. Although the main application of these models is the computation of turbulent flames, this work focuses on the performance of flamelet concept in laminar flame simulations removing, in this way, turbulence closure interactions. A well-known coflow methane/air laminar flame is selected. Five levels of premixing are taken into account from an equivalence ratio {phi}={infinity} (nonpremixed) to {phi}=2.464. Results obtained using the flamelet approaches are compared to data obtained from the detailed solution of the complete transport equations using primitive variables. Numerical simulations of a counterflow flame are also presented to support the discussion of the results. Special emphasis is given to the analysis of the scalar dissipation rate modeling. (author)

[New approaches in pharmacology: numerical modelling and simulation].

Science.gov (United States)

Boissel, Jean-Pierre; Cucherat, Michel; Nony, Patrice; Dronne, Marie-Aimée; Kassaï, Behrouz; Chabaud, Sylvie

2005-01-01

The complexity of pathophysiological mechanisms is beyond the capabilities of traditional approaches. Many of the decision-making problems in public health, such as initiating mass screening, are complex. Progress in genomics and proteomics, and the resulting extraordinary increase in knowledge with regard to interactions between gene expression, the environment and behaviour, the customisation of risk factors and the need to combine therapies that individually have minimal though well documented efficacy, has led doctors to raise new questions: how to optimise choice and the application of therapeutic strategies at the individual rather than the group level, while taking into account all the available evidence? This is essentially a problem of complexity with dimensions similar to the previous ones: multiple parameters with nonlinear relationships between them, varying time scales that cannot be ignored etc. Numerical modelling and simulation (in silico investigations) have the potential to meet these challenges. Such approaches are considered in drug innovation and development. They require a multidisciplinary approach, and this will involve modification of the way research in pharmacology is conducted.

Phacoemulsification with intraocular lens implantation in primary angle-closure suspect, primary angle-closure and primary angle-closure glaucoma with cataract

Directory of Open Access Journals (Sweden)

Kun Zeng

2013-08-01

Full Text Available AIM: To evaluate the features and clinical outcomes of cataract extraction by phacoemulsification with intraocular lens implantation in primary angle-closure suspect(PACS, primary angle-closure(PACand primary angle-closure glaucoma(PACGwith cataract.METHODS:Phacoemulsification with intraocular lens implantation was performed on 86 cases(86 eyesdiagnosed as PACS, PAC and PACG co-existing cataract from January to December 2012. All cases were followed up for 3 months to 1 year. Pre-operative and post-operative visual acuity, intraocular pressure(IOP, gonioscopy, ultrasound biomicroscopy(UBM, visual field and usage of anti-glaucomaous eye drops were recorded.RESULTS:Zonular dialysis existed in 19 eyes(22%. The post-operative visual acuity improved in 84 eyes(98%. The post-operative visual acuity was CONCLUSION: PACS, PAC and PACG co-existing zonular dialysis is common. Phacoemulsification with IOL implantation can reduce IOP, deepen anterior chamber and open angle.

40 CFR 264.178 - Closure.

Science.gov (United States)

2010-07-01

... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE, AND DISPOSAL FACILITIES Use and Management of Containers § 264.178 Closure. At closure, all hazardous waste and hazardous waste residues must be removed...

Closure report for N Reactor

International Nuclear Information System (INIS)

1994-01-01

This report has been prepared to satisfy Section 3156(b) of Public Law 101-189 (Reports in Connection with Permanent Closures of Department of Energy Defense Nuclear Facilities), which requires submittal of a Closure Report to Congress by the Secretary of Energy upon the permanent cessation of production operations at a US Department of Energy (DOE) defense nuclear facility (Watkins 1991). This closure report provides: (1) A complete survey of the environmental problems at the facility; (2) Budget quality data indicating the cost of environmental restoration and other remediation and cleanup efforts at the facility; (3) A proposed cleanup schedule

Closure report for N Reactor

Energy Technology Data Exchange (ETDEWEB)

1994-01-01

This report has been prepared to satisfy Section 3156(b) of Public Law 101-189 (Reports in Connection with Permanent Closures of Department of Energy Defense Nuclear Facilities), which requires submittal of a Closure Report to Congress by the Secretary of Energy upon the permanent cessation of production operations at a US Department of Energy (DOE) defense nuclear facility (Watkins 1991). This closure report provides: (1) A complete survey of the environmental problems at the facility; (2) Budget quality data indicating the cost of environmental restoration and other remediation and cleanup efforts at the facility; (3) A proposed cleanup schedule.

Mandatory Closure Versus Nonintervention for Patent Ductus Arteriosus in Very Preterm Infants.

Science.gov (United States)

Sung, Se In; Chang, Yun Sil; Chun, Ji Young; Yoon, Shin Ae; Yoo, Hye Soo; Ahn, So Yoon; Park, Won Soon

2016-10-01

To determine whether a nonintervention approach for treating hemodynamically significant patent ductus arteriosus (PDA) is associated with decreased mortality and/or morbidity compared with a mandatory closure approach in extremely low birth weight infants. We reviewed the medical records of 178 infants of 23-26 weeks' gestational age with PDA, requiring ventilator treatment, and with hemodynamically significant PDA ≥2 mm in size. Mandatory closure was used during period I (July 2009 to December 2011, n = 81), and nonintervention was used during period II (January 2012 to June 2014, n = 97). During period I, 64% of infants were first treated with indomethacin, and 82% were ultimately ligated surgically. During period II, no infant was treated with indomethacin and/or ligation. The average postnatal day of PDA closure was day 13 and day 44 during periods I and II, respectively. There was significantly more use of diuretics and fluid restriction during period II compared with period I. There was no difference in mortality or morbidities such as necrotizing enterocolitis or intraventricular hemorrhage. The incidence of bronchopulmonary dysplasia (BPD) and the propensity score adjusted OR of BPD were significantly lower during period II compared with period I. Despite longer PDA exposure, nonintervention was associated with significantly less BPD compared with mandatory closure. Additional study is warranted to determine the benefits and risks of non-intervention for the hemodynamically significant PDA in extremely low birth weight infants. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

Femoral Artery Stenosis Following Percutaneous Closure Using a Starclose Closure Device

International Nuclear Information System (INIS)

Bent, Clare Louise; Kyriakides, Constantinos; Matson, Matthew

2008-01-01

Starclose (Abbott Vascular Devices, Redwood City, CA) is a new arterial closure device that seals a femoral puncture site with an extravascular star-shaped nitinol clip. The clip projects small tines into the arterial wall which fold inward, causing the arterial wall to pucker, producing a purse-string-like seal closing the puncture site. The case history is that of a 76-year-old female patient who underwent day-case percutaneous diagnostic coronary angiography. A Starclose femoral artery closure device was used to achieve hemostasis with subsequent femoral artery stenosis.

9 CFR 318.301 - Containers and closures.

Science.gov (United States)

2010-01-01

... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Containers and closures. 318.301... Canning and Canned Products § 318.301 Containers and closures. (a) Examination and cleaning of empty containers. (1) Empty containers, closures, and flexible pouch roll stock shall be evaluated by the...

75 FR 29322 - Base Closure and Realignment

Science.gov (United States)

2010-05-25

... DEPARTMENT OF DEFENSE Office of the Secretary Base Closure and Realignment AGENCY: Office of...)(ii) of the Defense Base Closure and Realignment Act of 1990. It provides a partial list of military installations closing or realigning pursuant to the 2005 Base Closure and Realignment (BRAC) Report. It also...

Component-oriented approach to the development and use of numerical models in high energy physics

International Nuclear Information System (INIS)

Amelin, N.S.; Komogorov, M.Eh.

2002-01-01

We discuss the main concepts of a component approach to the development and use of numerical models in high energy physics. This approach is realized as the NiMax software system. The discussed concepts are illustrated by numerous examples of the system user session. In appendix chapter we describe physics and numerical algorithms of the model components to perform simulation of hadronic and nuclear collisions at high energies. These components are members of hadronic application modules that have been developed with the help of the NiMax system. Given report is served as an early release of the NiMax manual mainly for model component users

Elliptic blending model : A new near-wall Reynolds-stress turbulence closure

NARCIS (Netherlands)

Manceau, R.; Hanjali?, K.

2001-01-01

A new approach to modeling the effects of a solid wall in one-point second-moment (Reynolds-stress) turbulence closures is presented. The model is based on the relaxation of an inhomogeneous (near-wall) formulation of the pressure–strain tensor towards the chosen conventional homogeneous

Closure Report Central Nevada Test Area Subsurface Corrective Action Unit 443 January 2016

Energy Technology Data Exchange (ETDEWEB)

Findlay, Rick [US Department of Energy, Washington, DC (United States). Office of Legacy Management

2015-11-01

The U.S. Department of Energy (DOE) Office of Legacy Management (LM) prepared this Closure Report for the subsurface Corrective Action Unit (CAU) 443 at the Central Nevada Test Area (CNTA), Nevada, Site. CNTA was the site of a 0.2- to 1-megaton underground nuclear test in 1968. Responsibility for the site’s environmental restoration was transferred from the DOE, National Nuclear Security Administration, Nevada Field Office to LM on October 1, 2006. The environmental restoration process and corrective action strategy for CAU 443 are conducted in accordance with the Federal Facility Agreement and Consent Order (FFACO 1996, as amended 2011) and all applicable Nevada Division of Environmental Protection (NDEP) policies and regulations. This Closure Report provides justification for closure of CAU 443 and provides a summary of completed closure activities; describes the selected corrective action alternative; provides an implementation plan for long-term monitoring with well network maintenance and approaches/policies for institutional controls (ICs); and presents the contaminant, compliance, and use-restriction boundaries for the site.

Delayed primary closure of bladder exstrophy: immediate postoperative management leading to successful outcomes.

Science.gov (United States)

Baradaran, Nima; Stec, Andrew A; Schaeffer, Anthony J; Gearhart, John P; Mathews, Ranjiv I

2012-02-01

To present the critical features of our postoperative plan for children undergoing delayed primary bladder closure because appropriate postoperative management is crucial to successful exstrophy repair. Using an institutionally approved database, patients with bladder exstrophy whose primary bladder closure was performed at least 1 month after birth were identified. All aspects of the postoperative management were reviewed. A total of 20 patients (18 boys) were identified: 19 with classic bladder extrosphy and 1 with an exstrophy variant. The patients underwent closure at a mean age of 9.9 months. All patients underwent pelvic osteotomy and immobilization for an average of 34.8 days. Analgesia was administered by way of a tunneled epidural catheter in 90% of patients for an average of 18.8 days, and 12 patients (60%) required adjunct intravenous analgesia. Bilateral ureteral catheters and suprapubic tubes were used in all patients. Total parenteral nutrition was administered to 10 (83%) of 12 patients who underwent closure after 2000. All patients received preoperative antibiotics and 2 weeks of postoperative intravenous antibiotics that was followed by oral prophylaxis. The mean hospital stay was 6.3 weeks. With an average follow-up of 7.4 years, delayed closure was 100% successful. Successful delayed primary closure of bladder exstrophy requires a multidisciplinary approach. The keys to success include osteotomy, pelvic immobilization, analgesia, nutritional support, maximal bladder drainage, and infection prophylaxis. Copyright © 2012. Published by Elsevier Inc.

An Analytical Model for Fatigue Life Prediction Based on Fracture Mechanics and Crack Closure

DEFF Research Database (Denmark)

Ibsø, Jan Behrend; Agerskov, Henning

1996-01-01

test specimens are compared with fatigue life predictions using a fracture mechanics approach. In the calculation of the fatigue life, the influence of the welding residual stresses and crack closure on the fatigue crack growth is considered. A description of the crack closure model for analytical...... of the analytical fatigue lives. Both the analytical and experimental results obtained show that the Miner rule may give quite unconservative predictions of the fatigue life for the types of stochastic loading studied....... determination of the fatigue life is included. Furthermore, the results obtained in studies of the various parameters that have an influence on the fatigue life, are given. A very good agreement between experimental and analytical results is obtained, when the crack closure model is used in determination...

An Analytical Model for Fatigue Life Prediction Based on Fracture Mechanics and Crack Closure

DEFF Research Database (Denmark)

Ibsø, Jan Behrend; Agerskov, Henning

1996-01-01

test specimens are compared with fatigue life predictions using a fracture mechanics approach. In the calculation of the fatigue life, the influence of the welding residual stresses and crack closure on the fatigue crack growth is considered. A description of the crack closure model for analytical...... determination of the fatigue life is included. Furthermore, the results obtained in studies of the various parameters that have an influence on the fatigue life, are given. A very good agreement between experimental and analytical results is obtained, when the crack closure model is used in determination...... of the analytical fatigue lives. Both the analytical and experimental results obtained show that the Miner rule may give quite unconservative predictions of the fatigue life for the types of stochastic loading studied....

Numerical calculation of backfilling of scour holes

DEFF Research Database (Denmark)

Sumer, B. Mutlu; Baykal, Cüneyt; Fuhrman, David R.

2014-01-01

A fully-coupled hydrodynamic and morphologic CFD model is presented for simulating backfilling processes around structures. The hydrodynamic model is based on Reynolds-averaged Navier-Stokes equations, coupled with two-equation k-ω turbulence closure. The sediment transport model consists of sepa...... of structures: piles, and pipelines. Initial scour holes are generated by the same model. The numerical results appear to be in accord with the existing experimental information....

High-order non-uniform grid schemes for numerical simulation of hypersonic boundary-layer stability and transition

International Nuclear Information System (INIS)

Zhong Xiaolin; Tatineni, Mahidhar

2003-01-01

The direct numerical simulation of receptivity, instability and transition of hypersonic boundary layers requires high-order accurate schemes because lower-order schemes do not have an adequate accuracy level to compute the large range of time and length scales in such flow fields. The main limiting factor in the application of high-order schemes to practical boundary-layer flow problems is the numerical instability of high-order boundary closure schemes on the wall. This paper presents a family of high-order non-uniform grid finite difference schemes with stable boundary closures for the direct numerical simulation of hypersonic boundary-layer transition. By using an appropriate grid stretching, and clustering grid points near the boundary, high-order schemes with stable boundary closures can be obtained. The order of the schemes ranges from first-order at the lowest, to the global spectral collocation method at the highest. The accuracy and stability of the new high-order numerical schemes is tested by numerical simulations of the linear wave equation and two-dimensional incompressible flat plate boundary layer flows. The high-order non-uniform-grid schemes (up to the 11th-order) are subsequently applied for the simulation of the receptivity of a hypersonic boundary layer to free stream disturbances over a blunt leading edge. The steady and unsteady results show that the new high-order schemes are stable and are able to produce high accuracy for computations of the nonlinear two-dimensional Navier-Stokes equations for the wall bounded supersonic flow

Sandwich wound closure reduces the risk of cerebrospinal fluid leaks in posterior fossa surgery

Directory of Open Access Journals (Sweden)

Verena Heymanns

2016-07-01

Full Text Available Posterior fossa surgery is demanding and hides a significant number of obstacles starting from the approach to the wound closure. The risk of cerebrospinal fluid (CSF leakage in posterior fossa surgery given in the literature is around 8%. The present study aims to introduce a sandwich closure of the dura in posterior fossa surgery, which reduces significantly the number of CSF leaks (3.8% in the patients treated in our department. Three hundred and ten patients treated in our hospital in the years 2009-2013 for posterior fossa pathologies were retrospectively evaluated. The dura closure method was as following: lyophilized dura put under the dura and sealed with fibrin glue and sutures, dura adapting stitches, TachoSil® (Takeda Pharma A/S, Roskilde, Denmark, Gelfoam® (Pfizer Inc., New York, NY, USA and polymethylmethacrylate (osteoclastic craniotomy. The incidence of postsurgical complications associated with the dural closure like CSF leakage, infections, bleeding is evaluated. Only 3.8% of patients developed CSF leakage and only 0.5% needed a second surgery for CSF leakage closure. Two percent had a cerebellar bleeding with no need for re-operation and 3% had a wound infection treated with antibiotics. The sandwich wound closure we are applying for posterior fossa surgery in our patients correlates with a significant reduction of CSF leaks compared to the literature.

Numerical approach to one-loop integrals

International Nuclear Information System (INIS)

Fujimoto, Junpei; Shimizu, Yoshimitsu; Kato, Kiyoshi; Oyanagi, Yoshio.

1992-01-01

Two numerical methods are proposed for the calculation of one-loop scalar integrals. In the first method, the singularity is cancelled by the symmetrization of the integrand and the integration is done by a Monte-Carlo method. In the second one, after the transform of the integrand into a standard form, the integral is reduced into a regular numerical integral. These methods provide us practical tools to evaluate one-loop Feynman diagrams with desired numerical accuracy. They are extended to the integral with numerator and the treatment of the one-loop virtual correction to the cross section is also presented. (author)

Closure Welding of Plutonium Bearing Storage Containers

International Nuclear Information System (INIS)

Cannell, G.R.

2002-01-01

A key element in the Department of Energy (DOE) strategy for the stabilization, packaging and storage of plutonium-bearing materials involves closure welding of DOE-STD-3013 Outer Containers (3013 container). The 3013 container provides the primary barrier and pressure boundary preventing release of plutonium-bearing materials to the environment. The final closure (closure weld) of the 3013 container must be leaktight, structurally sound and meet DOE STD 3013 specified criteria. This paper focuses on the development, qualification and demonstration of the welding process for the closure welding of Hanford PFP 3013 outer containers

Closure End States for Facilities, Waste Sites, and Subsurface Contamination - 12543

Energy Technology Data Exchange (ETDEWEB)

Gerdes, Kurt; Chamberlain, Grover; Whitehurst, Latrincy; Marble, Justin [Office of Groundwater and Soil Remediation, U.S. Department of Energy, Washington, DC 20585 (United States); Wellman, Dawn [Pacific Northwest National Laboratory, Richland, Washington 99352 (United States); Deeb, Rula; Hawley, Elisabeth [ARCADIS U.S., Inc., Emeryville, CA 94608 (United States)

2012-07-01

) instead of focusing on long-term cleanup requirements. An acknowledgement of the long timeframe for complete restoration and the need for long-term management can also help a site transition from the process of pilot testing different remedial strategies to selecting a final remedy and establishing a long-term management and monitoring approach. This approach has led to cost savings and the more efficient use of resources across the Department of Defense complex and at numerous industrial sites across the U.S. Defensible end states provide numerous benefits for the DOE environmental remediation programs including cost-effective, sustainable long-term monitoring strategies, remediation and site transition decision support, and long-term management of closure sites. (authors)

Fuel channel closure and adapter

International Nuclear Information System (INIS)

Cashen, W.S.

1985-01-01

This invention provides a mechanical closure/actuating ram combination particularly suited for use in sealing the ends of the pressure tubes when a CANDU-type reactor is refueled. It provides a cluster that may be inserted into a fuel channel end fitting to provide at least partial closing off of a pressure tube while permitting the disengagement of the fueling machine and its withdrawal from the closure for other purposes. The invention also provides a ram/closure combination wherein the application of loading force to a deformable sealing disk is regulated by a massive load bar component forming part of the fueling machine and being therefore accessible for maintenance or replacement

Restaurant closures

CERN Document Server

Novae Restauration

2012-01-01

Christmas Restaurant closures Please note that the Restaurant 1 and Restaurant 3 will be closed from Friday, 21 December at 5 p.m. to Sunday, 6 January, inclusive. They will reopen on Monday, 7 January 2013.   Restaurant 2 closure for renovation To meet greater demand and to modernize its infrastructure, Restaurant 2 will be closed from Monday, 17 December. On Monday, 14 January 2013, Sophie Vuetaz’s team will welcome you to a renovated self-service area on the 1st floor. The selections on the ground floor will also be expanded to include pasta and pizza, as well as snacks to eat in or take away. To ensure a continuity of service, we suggest you take your break at Restaurant 1 or Restaurant 3 (Prévessin).

Electromagnetic scattering problems -Numerical issues and new experimental approaches of validation

Energy Technology Data Exchange (ETDEWEB)

Geise, Robert; Neubauer, Bjoern; Zimmer, Georg [University of Braunschweig, Institute for Electromagnetic Compatibility, Schleinitzstrasse 23, 38106 Braunschweig (Germany)

2015-03-10

Electromagnetic scattering problems, thus the question how radiated energy spreads when impinging on an object, are an essential part of wave propagation. Though the Maxwell’s differential equations as starting point, are actually quite simple,the integral formulation of an object’s boundary conditions, respectively the solution for unknown induced currents can only be solved numerically in most cases.As a timely topic of practical importance the scattering of rotating wind turbines is discussed, the numerical description of which is still based on rigorous approximations with yet unspecified accuracy. In this context the issue of validating numerical solutions is addressed, both with reference simulations but in particular with the experimental approach of scaled measurements. For the latter the idea of an incremental validation is proposed allowing a step by step validation of required new mathematical models in scattering theory.

Anterior Segment Imaging Predicts Incident Gonioscopic Angle Closure.

Science.gov (United States)

Baskaran, Mani; Iyer, Jayant V; Narayanaswamy, Arun K; He, Yingke; Sakata, Lisandro M; Wu, Renyi; Liu, Dianna; Nongpiur, Monisha E; Friedman, David S; Aung, Tin

2015-12-01

To investigate the incidence of gonioscopic angle closure after 4 years in subjects with gonioscopically open angles but varying degrees of angle closure detected on anterior segment optical coherence tomography (AS OCT; Visante; Carl Zeiss Meditec, Dublin, CA) at baseline. Prospective, observational study. Three hundred forty-two subjects, mostly Chinese, 50 years of age or older, were recruited, of whom 65 were controls with open angles on gonioscopy and AS OCT at baseline, and 277 were cases with baseline open angles on gonioscopy but closed angles (1-4 quadrants) on AS OCT scans. All subjects underwent gonioscopy and AS OCT at baseline (horizontal and vertical single scans) and after 4 years. The examiner performing gonioscopy was masked to the baseline and AS OCT data. Angle closure in a quadrant was defined as nonvisibility of the posterior trabecular meshwork by gonioscopy and visible iridotrabecular contact beyond the scleral spur in AS OCT scans. Gonioscopic angle closure in 2 or 3 quadrants after 4 years. There were no statistically significant differences in age, ethnicity, or gender between cases and controls. None of the control subjects demonstrated gonioscopic angle closure after 4 years. Forty-eight of the 277 subjects (17.3%; 95% confidence interval [CI], 12.8-23; P < 0.0001) with at least 1 quadrant of angle closure on AS OCT at baseline demonstrated gonioscopic angle closure in 2 or more quadrants, whereas 28 subjects (10.1%; 95% CI, 6.7-14.6; P < 0.004) demonstrated gonioscopic angle closure in 3 or more quadrants after 4 years. Individuals with more quadrants of angle closure on baseline AS OCT scans had a greater likelihood of gonioscopic angle closure developing after 4 years (P < 0.0001, chi-square test for trend for both definitions of angle closure). Anterior segment OCT imaging at baseline predicts incident gonioscopic angle closure after 4 years among subjects who have gonioscopically open angles and iridotrabecular contact on AS OCT at

Holistic Considerations in Optimizing a Sterile Product Package to Ensure Container Closure Integrity.

Science.gov (United States)

Degrazio, Fran L

2018-01-01

A new major chapter dealing with container closure integrity was released by the United States Pharmacopeial Convention. Chapter provides a significant amount of education and guidance concerning test methodologies to prove that a system is integral and safe for use. The test method used is only one of the major considerations in approaching the challenge of proving an integral system. This paper takes a holistic review of all the major considerations needed in qualifying a new vial system for container closure integrity. There is substantial interplay among many aspects in the process of sealing a vial. This review helps to define major risks that need to be considered and mitigated and reinforces the need to understand the maximum allowable leakage limit that is acceptable for a specific drug application. A typical risk-based approach considers materials, test methods, process, people, environment, and equipment. Each of these aspects is considered in some detail along with a recommended process flow for building a best practice, science-based approach. This approach will inform decision making for evaluating the correct combination of components and assuring they are assembled and tested in an appropriate manner. This work, once completed, can be the basis for a vial system platform or specific drug application qualification. LAY ABSTRACT: Container closure integrity is a fundamental requirement of every sterile drug package. With recent upgrading of compendia standards and guidance around this issue, there is an opportunity to better define a best practice approach to a complicated subject. It is important to recognize that there is substantial interplay among the components of the system, the process of assembly, and the test methods that are used. This paper takes a holistic approach to discussing these issues and identifying the risks that must be considered in assuring an integral container over the shelf life of a drug product. © PDA, Inc. 2018.

Randomized clinical trial of intestinal ostomy takedown comparing pursestring wound closure vs conventional closure to eliminate the risk of wound infection.

Science.gov (United States)

Camacho-Mauries, Daniel; Rodriguez-Díaz, José Luis; Salgado-Nesme, Noel; González, Quintín H; Vergara-Fernández, Omar

2013-02-01

The use of temporary stomas has been demonstrated to reduce septic complications, especially in high-risk anastomosis; therefore, it is necessary to reduce the number of complications secondary to ostomy takedowns, namely wound infection, anastomotic leaks, and intestinal obstruction. To compare the rates of superficial wound infection and patient satisfaction after pursestring closure of ostomy wound vs conventional linear closure. Patients undergoing colostomy or ileostomy closure between January 2010 and February 2011 were randomly assigned to linear closure (n = 30) or pursestring closure (n = 31) of their ostomy wound. Wound infection within 30 days of surgery was defined as the presence of purulent discharge, pain, erythema, warmth, or positive culture for bacteria. Patient satisfaction, healing time, difficulty managing the wound, and limitation of activities were analyzed with the Likert questionnaire. The infection rate for the control group was 36.6% (n = 11) vs 0% in the pursestring closure group (p ostomy wound closure (shorter healing time and improved patient satisfaction).

Catheter closure of patent foramen ovale in patients with cryptogenic cerebrovascular accidents: initial experiences in Japan.

Science.gov (United States)

Kijima, Yasufumi; Akagi, Teiji; Nakagawa, Koji; Taniguchi, Manabu; Ueoka, Akira; Deguchi, Kentaro; Toh, Norihisa; Oe, Hiroki; Kusano, Kengo; Sano, Shunji; Ito, Hiroshi

2014-01-01

Although numerous studies have shown an association between a patent foramen ovale (PFO) and cryptogenic cerebrovascular accidents (CVA), there has been no definitive control study that demonstrated the benefit of percutaneous device closure of a PFO compared to medical therapy in patients with CVA. Additionally, few clinical data exist for Japanese patients in this field. We demonstrate the initial experiences in catheter closure of a PFO as secondary prevention of CVA in Japan. Catheter closure of a PFO was attempted in 7 patients who were diagnosed with cryptogenic CVA. Mean age at the procedure was 54 ± 19 years. The presence of spontaneous interatrial right-to-left shunts was demonstrated by transesophageal contrast echocardiography without Valsalva maneuver in all of the patients. Amplatzer Cribriform device (n = 4) or Amplatzer PFO Occluder (n = 3) was used for the procedure and was successfully deployed. Device-related complications were not observed at the time of the procedure or during the follow-up period (mean period of 16 ± 9 months). Catheter closure of a PFO could be safely performed with Amplatzer Cribriform or Amplatzer PFO Occluder. This procedure may contribute to prevention of recurrent cryptogenic CVA in Japanese patients.

Patent ductus arteriosus closure using an Amplatzer(™) ventricular septal defect closure device.

Science.gov (United States)

Fernando, Rajeev; Koranne, Ketan; Loyalka, Pranav; Kar, Biswajit; Gregoric, Igor

2013-01-01

The ductus arteriosus originates from the persistence of the distal portion of the left sixth aortic arch. It connects the descending aorta (immediately distal to the left subclavian artery) to the roof of the main pulmonary artery, near the origin of the left pulmonary artery. Persistence of the duct beyond 48 h after birth is abnormal and results in patent ductus arteriosus (PDA). PDA is rare in adults because it is usually discovered and treated in childhood. Mechanical closure remains the definitive therapy because the patency of ductus arteriosus may lead to multiple complications, depending on the size and flow through the ductus. PDA closure is indicated in patients with symptoms and evidence of left heart enlargement, and in patients with elevated pulmonary pressures when reversal is possible. Transcatheter closure is the preferred technique in adults because it avoids sternotomy, reduces the length of hospital stay and is associated with fewer complications compared with surgery. First demonstrated in 1967, both the technique and the occluder devices used have since evolved. However, designing an ideal PDA occluder has been a challenge due to the variability in size, shape and orientation of PDAs. The present article describes a case involving a 35-year-old woman who presented to the Center for Advanced Heart Failure (Houston, USA) with congestive heart failure due to a large PDA, which was successfully occluded using an Amplatzer (St Jude Medical, USA) muscular ventricular septal defect closure device. The wider waist and dual-retention discs of these ventricular septal defect closure devices may be important factors to consider in the future development of devices for the occlusion of large PDAs.

Temporary Closure of the Open Abdomen: A Systematic Review on Delayed Primary Fascial Closure in Patients with an Open Abdomen

NARCIS (Netherlands)

Boele van Hensbroek, Pieter; Wind, Jan; Dijkgraaf, Marcel G. W.; Busch, Olivier R. C.; Goslings, J. Carel

2009-01-01

Background This study was designed to systematically review the literature to assess which temporary abdominal closure (TAC) technique is associated with the highest delayed primary fascial closure (FC) rate. In some cases of abdominal trauma or infection, edema or packing precludes fascial closure

Special closures for steel drum shipping containers

International Nuclear Information System (INIS)

Bonzon, L.L.; Otts, J.V.

1976-01-01

The objective of this program was to develop special lid closures for typical, steel drum, radioactive material shipping containers. Previous experience and testing had shown that the existing container was adequate to withstand the required environmental tests for certification, but that the lid and closure were just marginally effective. Specifically, the lid closure failed to consistently maintain a tight seal between the container and the lid after drop tests, thus causing the package contents to be vulnerable in the subsequent fire test. Recognizing the deficiency, the United States Energy Research and Development Administration requested the development of new closure(s) which would: (1) be as strong and resistant to a drop as the bottom of the container; (2) have minimal economic impact on the overall container cost; (3) maximize the use of existing container designs; (4) consider crush loads; and (5) result in less dependence on personnel and loading procedures. Several techniques were evaluated and found to be more effective than the standard closure mechanism. Of these, three new closure techniques were designed, fabricated, and proven to be structurally adequate to provide containment when a 454-kg drum was drop tested from 9.14-m onto an unyielding surface. The three designs were: (1) a 152-mm long lid extension or skirt welded to the standard drum lid, (2) a separate inner lid, with 152-mm long skirt and (3) C-clamps used at the container-lid interface. Based upon structural integrity, economic impact, and minimal design change, the lid extension is the recommended special closure

Water hammer caused by closure of turbine safety spherical valves

Science.gov (United States)

Karadžić, U.; Bergant, A.; Vukoslavčević, P.

2010-08-01

This paper investigates water hammer effects caused by closure of spherical valves against the discharge. During the first phase of modernisation of Perućica high-head hydropower plant (HPP), Montenegro, safety spherical valves (inlet turbine valves) have been refurbished on the first two Pelton turbine units. The valve closure is controlled by the valve actuator (hydraulic servomotor). Because the torque acting on the valve body is dependent on flow conditions the valve closing time may vary significantly for different flow velocities (passive valve). For the passive valve the torques acting on the valve body should be considered in the valve model. The valve closing time results from numerical simulation. On the contrary, for the active valve the valve closing time is assumed prior to simulation. The spherical valve boundary condition is incorporated into the method of characteristics (MOC) algorithm. The staggered (diamond) grid in applying the MOC is used in this paper. The passive valve boundary condition is described by the water hammer equations, the valve equation that relates discharge to pressure head drop and the dynamic equation of the valve body motion (torque equation). The active valve boundary condition is described by the first two equations, respectively. Standard quasi-steady friction model is used for estimating friction losses in plant's tunnel and penstocks. Numerical results using both the active and the passive spherical valve models are compared with results of measurements. It has been found that the influence of flow conditions on the spherical valve closing time is minor for the cases considered. Computed and measured results agree reasonably well.

Water hammer caused by closure of turbine safety spherical valves

International Nuclear Information System (INIS)

Karadzic, U; Vukoslavcevic, P; Bergant, A

2010-01-01

This paper investigates water hammer effects caused by closure of spherical valves against the discharge. During the first phase of modernisation of Perucica high-head hydropower plant (HPP), Montenegro, safety spherical valves (inlet turbine valves) have been refurbished on the first two Pelton turbine units. The valve closure is controlled by the valve actuator (hydraulic servomotor). Because the torque acting on the valve body is dependent on flow conditions the valve closing time may vary significantly for different flow velocities (passive valve). For the passive valve the torques acting on the valve body should be considered in the valve model. The valve closing time results from numerical simulation. On the contrary, for the active valve the valve closing time is assumed prior to simulation. The spherical valve boundary condition is incorporated into the method of characteristics (MOC) algorithm. The staggered (diamond) grid in applying the MOC is used in this paper. The passive valve boundary condition is described by the water hammer equations, the valve equation that relates discharge to pressure head drop and the dynamic equation of the valve body motion (torque equation). The active valve boundary condition is described by the first two equations, respectively. Standard quasi-steady friction model is used for estimating friction losses in plant's tunnel and penstocks. Numerical results using both the active and the passive spherical valve models are compared with results of measurements. It has been found that the influence of flow conditions on the spherical valve closing time is minor for the cases considered. Computed and measured results agree reasonably well.

Water hammer caused by closure of turbine safety spherical valves

Energy Technology Data Exchange (ETDEWEB)

Karadzic, U; Vukoslavcevic, P [Faculty of Mechanical Engineering, University of Montenegro Dzordza Vasingtona nn, Podgorica, 81000 (Montenegro); Bergant, A, E-mail: uros.karadzic@ac.m [LitostrojPower d.o.o., Litostrojska 50, Ljubljana, 1000 (Slovenia)

2010-08-15

This paper investigates water hammer effects caused by closure of spherical valves against the discharge. During the first phase of modernisation of Perucica high-head hydropower plant (HPP), Montenegro, safety spherical valves (inlet turbine valves) have been refurbished on the first two Pelton turbine units. The valve closure is controlled by the valve actuator (hydraulic servomotor). Because the torque acting on the valve body is dependent on flow conditions the valve closing time may vary significantly for different flow velocities (passive valve). For the passive valve the torques acting on the valve body should be considered in the valve model. The valve closing time results from numerical simulation. On the contrary, for the active valve the valve closing time is assumed prior to simulation. The spherical valve boundary condition is incorporated into the method of characteristics (MOC) algorithm. The staggered (diamond) grid in applying the MOC is used in this paper. The passive valve boundary condition is described by the water hammer equations, the valve equation that relates discharge to pressure head drop and the dynamic equation of the valve body motion (torque equation). The active valve boundary condition is described by the first two equations, respectively. Standard quasi-steady friction model is used for estimating friction losses in plant's tunnel and penstocks. Numerical results using both the active and the passive spherical valve models are compared with results of measurements. It has been found that the influence of flow conditions on the spherical valve closing time is minor for the cases considered. Computed and measured results agree reasonably well.

Soil Vapor Extraction System Optimization, Transition, and Closure Guidance

Energy Technology Data Exchange (ETDEWEB)

Truex, Michael J.; Becker, Dave; Simon, Michelle A.; Oostrom, Martinus; Rice, Amy K.; Johnson, Christian D.

2013-02-08

Soil vapor extraction (SVE) is a prevalent remediation approach for volatile contaminants in the vadose zone. A diminishing rate of contaminant extraction over time is typically observed due to 1) diminishing contaminant mass, and/or 2) slow rates of removal for contamination in low-permeability zones. After a SVE system begins to show indications of diminishing contaminant removal rate, SVE performance needs to be evaluated to determine whether the system should be optimized, terminated, or transitioned to another technology to replace or augment SVE. This guidance specifically addresses the elements of this type of performance assessment. While not specifically presented, the approach and analyses in this guidance could also be applied at the onset of remediation selection for a site as a way to evaluate current or future impacts to groundwater from vadose zone contamination. The guidance presented here builds from existing guidance for SVE design, operation, optimization, and closure from the U.S. Environmental Protection Agency, U.S. Army Corps of Engineers, and the Air Force Center for Engineering and the Environment. The purpose of the material herein is to clarify and focus on the specific actions and decisions related to SVE optimization, transition, and/or closure.

Some Recent Developments in Turbulence Closure Modeling

Science.gov (United States)

Durbin, Paul A.

2018-01-01

Turbulence closure models are central to a good deal of applied computational fluid dynamical analysis. Closure modeling endures as a productive area of research. This review covers recent developments in elliptic relaxation and elliptic blending models, unified rotation and curvature corrections, transition prediction, hybrid simulation, and data-driven methods. The focus is on closure models in which transport equations are solved for scalar variables, such as the turbulent kinetic energy, a timescale, or a measure of anisotropy. Algebraic constitutive representations are reviewed for their role in relating scalar closures to the Reynolds stress tensor. Seamless and nonzonal methods, which invoke a single closure model, are reviewed, especially detached eddy simulation (DES) and adaptive DES. Other topics surveyed include data-driven modeling and intermittency and laminar fluctuation models for transition prediction. The review concludes with an outlook.

How the Lean Management System is Working on a Closure Project - 13242

Energy Technology Data Exchange (ETDEWEB)

Mowery, Carol [Washington Closure Hanford, 2620 Fermi, Richland, Washington, 99354 (United States)

2013-07-01

Washington Closure Hanford, LLC (WCH) manages the River Corridor Closure Project (RCCP), a 10-year contract, in which WCH will clean up 220 mi{sup 2} of contaminated land at the Hanford Site in Richland, Washington. Strategic planning sessions in 2009 identified key performance areas that were essential to closure and in which focused change could result in dramatic performance improvement. Lean Management Systems (Lean) was selected as the methodology to achieve the desired results. The Lean Process is built upon the fundamentals of the power of respect for people and the practice of continuous process improvement. Lean uses week-long, focused sessions that teach a selected team the techniques to recognize waste within their own work processes, propose potential solutions, and then conduct experiments during the week to test their solutions. In 2011, the Lean process was implemented in the Waste Operations organization. From there it was expanded to closure documents, field remediation, and decommissioning and demolition. WCH identified the following Lean focus areas: 1) closure document processes that required extensive internal preparation, and lengthy external review and approval cycles; 2) allocation of limited transportation and waste disposal resources to meet aggressive remediation schedules; 3) effective start-of-the-day routines in field operations; 4) improved excavation and load-out processes; and 5) approaches to strengthen safety culture and support disciplined operations. Since the introduction of Lean, RCCP has realized many successes and also gained some unexpected benefits. (authors)

How the Lean Management System is Working on a Closure Project - 13242

International Nuclear Information System (INIS)

Mowery, Carol

2013-01-01

Washington Closure Hanford, LLC (WCH) manages the River Corridor Closure Project (RCCP), a 10-year contract, in which WCH will clean up 220 mi 2 of contaminated land at the Hanford Site in Richland, Washington. Strategic planning sessions in 2009 identified key performance areas that were essential to closure and in which focused change could result in dramatic performance improvement. Lean Management Systems (Lean) was selected as the methodology to achieve the desired results. The Lean Process is built upon the fundamentals of the power of respect for people and the practice of continuous process improvement. Lean uses week-long, focused sessions that teach a selected team the techniques to recognize waste within their own work processes, propose potential solutions, and then conduct experiments during the week to test their solutions. In 2011, the Lean process was implemented in the Waste Operations organization. From there it was expanded to closure documents, field remediation, and decommissioning and demolition. WCH identified the following Lean focus areas: 1) closure document processes that required extensive internal preparation, and lengthy external review and approval cycles; 2) allocation of limited transportation and waste disposal resources to meet aggressive remediation schedules; 3) effective start-of-the-day routines in field operations; 4) improved excavation and load-out processes; and 5) approaches to strengthen safety culture and support disciplined operations. Since the introduction of Lean, RCCP has realized many successes and also gained some unexpected benefits. (authors)

Biomechanics Strategies for Space Closure in Deep Overbite

Directory of Open Access Journals (Sweden)

Harryanto Wijaya

2013-07-01

Full Text Available Space closure is an interesting aspect of orthodontic treatment related to principles of biomechanics. It should be tailored individually based on patient’s diagnosis and treatment plan. Understanding the space closure biomechanics basis leads to achieve the desired treatment objective. Overbite deepening and losing posterior anchorage are the two most common unwanted side effects in space closure. Conventionally, correction of overbite must be done before space closure resulted in longer treatment. Application of proper space closure biomechanics strategies is necessary to achieve the desired treatment outcome. This cases report aimed to show the space closure biomechanics strategies that effectively control the overbite as well as posterior anchorage in deep overbite patients without increasing treatment time. Two patients who presented with class II division 1 malocclusion were treated with fixed orthodontic appliance. The primary strategies included extraction space closure on segmented arch that employed two-step space closure, namely single canine retraction simultaneously with incisors intrusion followed by enmasse retraction of four incisors by using differential moment concept. These strategies successfully closed the space, corrected deep overbite and controlled posterior anchorage simultaneously so that the treatment time was shortened. Biomechanics strategies that utilized were effective to achieve the desired treatment outcome.

Magnetisable container closure and means for its removal

International Nuclear Information System (INIS)

Barrett, W.I.

1984-01-01

A container has a closed lower end and an open upper end, is made of a non-magnetic material such as aluminium, and has a peripheral groove spaced from the open end. A disc-like closure is of magnetic material such as ferritic steel, has a pair of spring jaws joined to the disc by a joining member such that when the disc of the closure is in position closing the open end of the container, the jaws engage in groove and hold the closure in position. To remove the closure, it is engaged by magnetic means mounted for example on a wall and having a step such that when the container is moved laterally away the closure is retained by the magnetic means aided by the step and thereby the closure becomes removed from the container. (author)

Numerical solution of the full potential equation using a chimera grid approach

Science.gov (United States)

Holst, Terry L.

1995-01-01

A numerical scheme utilizing a chimera zonal grid approach for solving the full potential equation in two spatial dimensions is described. Within each grid zone a fully-implicit approximate factorization scheme is used to advance the solution one interaction. This is followed by the explicit advance of all common zonal grid boundaries using a bilinear interpolation of the velocity potential. The presentation is highlighted with numerical results simulating the flow about a two-dimensional, nonlifting, circular cylinder. For this problem, the flow domain is divided into two parts: an inner portion covered by a polar grid and an outer portion covered by a Cartesian grid. Both incompressible and compressible (transonic) flow solutions are included. Comparisons made with an analytic solution as well as single grid results indicate that the chimera zonal grid approach is a viable technique for solving the full potential equation.

Urethrovaginal fistula closure.

Science.gov (United States)

Clifton, Marisa M; Goldman, Howard B

2017-01-01

In the developed world, urethrovaginal fistulas are most the likely the result of iatrogenic injury. These fistulas are quite rare. Proper surgical repair requires careful dissection and tension-free closure. The objective of this video is to demonstrate the identification and surgical correction of an urethrovaginal fistula. The case presented is of a 59-year-old woman with a history of pelvic organ prolapse and symptomatic stress urinary incontinence who underwent vaginal hysterectomy, anterior colporrhaphy, posterior colporrhaphy, and synthetic sling placement. Postoperatively, she developed a mesh extrusion and underwent sling excision. After removal of her synthetic sling, she began to experience continuous urinary incontinence. Physical examination and cystourethroscopy demonstrated an urethrovaginal fistula at the midurethra. Options were discussed and the patient wished to undergo transvaginal fistula repair. The urethrovaginal fistula was intubated with a Foley catheter. The fistula tract was isolated and removed. The urethra was then closed with multiple tension-free layers. This video demonstrates several techniques for identifying and subsequently repairing an urethrovaginal fistula. Additionally, it demonstrates the importance of tension-free closure. Urethrovaginal fistulas are rare. They should be repaired with careful dissection and tension-free closure.

Derivation of quantitative acceptance criteria for disposal of radioactive waste to near surface facilities: Development and implementation of an approach for the post-closure phase

International Nuclear Information System (INIS)

Torres, C.

2000-01-01

The International Atomic Energy Agency has established a project to develop and illustrate, through practical examples, an approach that allows the derivation of quantitative waste acceptance criteria for near surface disposal of radioactive waste. The first phase focussed on the derivation of example post-closure safety waste acceptance criteria through the use of a safety assessment approach that allows for the derivation of values in a clear and well documented manner. The approach consists of five steps: the specification of the assessment context; the description of the disposal system; the development and justification of scenarios; the formulation and implementation of models; and the calculation and derivation of example values. The approach has been successfully used to derive activity values for the disposal of radioactive waste to illustrative near surface facilities. (author)

The simulation of solute transport: An approach free of numerical dispersion

International Nuclear Information System (INIS)

Carrera, J.; Melloni, G.

1987-01-01

The applicability of most algorithms for simulation of solute transport is limited either by instability or by numerical dispersion, as seen by a review of existing methods. A new approach is proposed that is free of these two problems. The method is based on the mixed Eulerian-Lagrangian formulation of the mass-transport problem, thus ensuring stability. Advection is simulated by a variation of reverse-particle tracking that avoids the accumulation of interpolation errors, thus preventing numerical dispersion. The algorithm has been implemented in a one-dimensional code. Excellent results are obtained, in comparison with an analytical solution. 36 refs., 14 figs., 1 tab

[An approach to vacuum-assisted closure therapy using the S-B Vac].

Science.gov (United States)

Nagayoshi, Yasuhiro; Kiyosawa, Jun; Mikami, Naofusa; Mizuno, Fumito; Noguchi, Yasuhisa; Kobata, Takashi; Yokote, Jun; Hida, Kenji; Shikata, Hiroo; Akita, Toshiaki

2010-09-01

Vacuum-assisted closure (VAC) therapy is increasingly applied for patients with wound dehiscence or mediastinitis caused by surgical site infection (SSI) after open-heart surgery. We have used wall suction for such cases in the past. But this method was an obstacle for improvement of the quality of life (QOL) of the patient. Since the S-B Vac is portable, this equipment may allow wound healing without decreasing QOL. Here, we report a case in which VAC therapy was performed using the S-B Vac.

A novel approach for the closure of challenging giant omphalocele

Directory of Open Access Journals (Sweden)

Barkat Ali

2015-11-01

Full Text Available Omphalocele is a congenital condition characterized by midline defect of the anterolateral abdominal wall whereby intra-abdominal contents covered by peritoneal sac are found herniated. It can be defined by size of defect or visceral contents. There are various ways of surgical management of omphalocele. Giant omphalocele presents particular challenge in reconstructing the abdominal wall. In this regard the use of tissues expansion as an adjunct in an attempt to recreate functional abdominal wall domain has been emerging. We are presenting a case of giant omphalocele that was closed with the help of extra peritoneal inter muscular tissue expanders.The patient was born at 37 weeks to a 33 year old healthy gravida 3, para 0 G3P0 mother via planned cesarean section. There were no prenatal, natal or postnatal complications. The giant omphalocele was diagnosed prenatally on screening Ultrasound. The patient remained in the neonatal intensive care unit for 6 weeks. The sac was large with abdominal contents including the entire liver. The sac was allowed to epithelialize completely over the course of two years. Due to the small size of the abdominal wall defect contents of the sac, loss of abdominal domain and inability of the abdominal cavity to accommodate the liver, we chose for rectangular tissue expander placement at age 30 months. 3 months later the patient was planned for tissue expander removal and abdominal wall closure. The tissue expanders were removed and omphalocele closure was performed. The patient has been followed up at 6 months and without recurrence of hernia.The management of giant omphalocele is technically challenging. Use of tissue expansion helps in recreating functional abdominal wall domain. There is growing evidence in the literature supporting the use of intra-abdominal tissue expansion in the management of giant omphalocele however because of hemodynamic consequences we think that the use of rectangular shaped, extra

Closure of shallow underground injection wells

International Nuclear Information System (INIS)

Veil, J.A.; Grunewald, B.

1993-01-01

Shallow injection wells have long been used for disposing liquid wastes. Some of these wells have received hazardous or radioactive wastes. According to US Environmental Protection Agency (EPA) regulations, Class IV wells are those injection wells through which hazardous or radioactive wastes are injected into or above an underground source of drinking water (USDW). These wells must be closed. Generally Class V wells are injection wells through which fluids that do not contain hazardous or radioactive wastes are injected into or above a USDW. Class V wells that are responsible for violations of drinking water regulations or that pose a threat to human health must also be closed. Although EPA regulations require closure of certain types of shallow injection wells, they do not provide specific details on the closure process. This paper describes the regulatory background, DOE requirements, and the steps in a shallow injection well closure process: Identification of wells needing closure; monitoring and disposal of accumulated substances; filling and sealing of wells; and remediation. In addition, the paper describes a major national EPA shallow injection well enforcement initiative, including closure plan guidance for wells used to dispose of wastes from service station operations

Reliability assessment of underground shaft closure

International Nuclear Information System (INIS)

Fossum, A.F.; Munson, D.E.

1994-01-01

The intent of the WIPP, being constructed in the bedded geologic salt deposits of Southeastern New Mexico, is to provide the technological basis for the safe disposal of radioactive Transuranic (TRU) wastes generated by the defense programs of the United States. In determining this technological basis, advanced reliability and structural analysis techniques are used to determine the probability of time-to-closure of a hypothetical underground shaft located in an argillaceous salt formation and filled with compacted crushed salt. Before being filled with crushed salt for sealing, the shaft provides access to an underground facility. Reliable closure of the shaft depends upon the sealing of the shaft through creep closure and recompaction of crushed backfill. Appropriate methods are demonstrated to calculate cumulative distribution functions of the closure based on laboratory determined random variable uncertainty in salt creep properties

Comparison of cost-effectiveness and postoperative outcome of device closure and open surgery closure techniques for treatment of patent ductus arteriosus

Directory of Open Access Journals (Sweden)

Alireza Ahmadi

2014-01-01

Full Text Available BACKGROUND: Various devices have been recently employed for percutaneous closure of the patent ductus arteriosus (PDA. Although the high effectiveness of device closure techniques has been clearly determined, a few studies have focused on the cost-effectiveness and also postoperative complications of these procedures in comparison with open surgery. The present study aimed to evaluate the clinical outcome and cost-effectiveness of PDA occlusion by Amplatzer and coil device in comparisong with open surgery. METHODS: In this cross-sectional study, a randomized sample of 201 patients aged 1 month to 16 years (105 patients with device closure and 96 patients with surgical closure was selected. The ratio of total pulmonary blood flow to total systemic blood flow, the Qp/Qs ratio, was measured using a pulmonary artery catheter. The cost analysis included direct medical care costs associated with device implantation and open surgery, as well as professional fees. All costs were calculated in Iranian Rials and then converted to US dollars. RESULTS: There was no statistical difference in mean Qp/Qs ratio before the procedure between the device closure group and the open surgery group (2.1 ± 0.7 versus 1.7 ± 0.6, P = 0.090. The mean measured costs were overall higher in the device closure group than in open closure group (948.87 ± 548.76 US$ versus 743.70 ± 696.91 US$, P < 0.001. This difference remained significant after adjustment for age and gender (Standardized Beta = 0.160, P = 0.031. PDA closure with the Amplatzer ductal occluder (1053.05 ± 525.73 US$ or with Nit-Occlud coils (PFM (912.73 ± 565.94 US$, P < 0.001 was more expensive than that via open surgery. However, the Cook detachable spring coils device closure (605.65 ± 194.62 US$, P = 0.650 had a non-significant cost difference with open surgery. No event was observed in the device closure group regarding in-hospital mortality or morbidity; however, in another group, 2 in-hospital deaths

WASTE PACKAGE OPERATIONS FY99 CLOSURE METHODS REPORT

Energy Technology Data Exchange (ETDEWEB)

M. C. Knapp

1999-09-23

The waste package (WP) closure weld development task is part of a larger engineering development program to develop waste package designs. The purpose of the larger waste package engineering development program is to develop nuclear waste package fabrication and closure methods that the Nuclear Regulatory Commission will find acceptable and will license for disposal of spent nuclear fuel (SNF), non-fuel components, and vitrified high-level waste within a Monitored Geologic Repository (MGR). Within the WP closure development program are several major development tasks, which, in turn, are divided into subtasks. The major tasks include: WP fabrication development, WP closure weld development, nondestructive examination (NDE) development, and remote in-service inspection development. The purpose of this report is to present the objectives, technical information, and work scope relating to the WP closure weld development.and NDE tasks and subtasks and to report results of the closure weld and NDE development programs for fiscal year 1999 (FY-99). The objective of the FY-99 WP closure weld development task was to develop requirements for closure weld surface and volumetric NDE performance demonstrations, investigate alternative NDE inspection techniques, and develop specifications for welding, NDE, and handling system integration. In addition, objectives included fabricating several flat plate mock-ups that could be used for NDE development, stress relief peening, corrosion testing, and residual stress testing.

WASTE PACKAGE OPERATIONS FY-99 CLOSURE METHODS REPORT

International Nuclear Information System (INIS)

M. C. Knapp

1999-01-01

The waste package (WP) closure weld development task is part of a larger engineering development program to develop waste package designs. The purpose of the larger waste package engineering development program is to develop nuclear waste package fabrication and closure methods that the Nuclear Regulatory Commission will find acceptable and will license for disposal of spent nuclear fuel (SNF), non-fuel components, and vitrified high-level waste within a Monitored Geologic Repository (MGR). Within the WP closure development program are several major development tasks, which, in turn, are divided into subtasks. The major tasks include: WP fabrication development, WP closure weld development, nondestructive examination (NDE) development, and remote in-service inspection development. The purpose of this report is to present the objectives, technical information, and work scope relating to the WP closure weld development.and NDE tasks and subtasks and to report results of the closure weld and NDE development programs for fiscal year 1999 (FY-99). The objective of the FY-99 WP closure weld development task was to develop requirements for closure weld surface and volumetric NDE performance demonstrations, investigate alternative NDE inspection techniques, and develop specifications for welding, NDE, and handling system integration. In addition, objectives included fabricating several flat plate mock-ups that could be used for NDE development, stress relief peening, corrosion testing, and residual stress testing

T-tube vs Primary Common Bile Duct Closure

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M R Joshi

2010-09-01

Full Text Available INTRODUCTION: Closure of the common bile duct over T-tube after exploration is a widely practiced traditional method. However, its use may give rise to many complications. We do primary closure of common bile duct after exploration. Aim of the study is to see the efficacy and safety of the primary closure. METHODS: Study was carried out to compare the results of both the techniques from 2006 to 2009 in the cases proven to have common bile duct stone with or without the features of obstructive jaundice. Post operative hospital stay and morbidities related to both the groups were recorded and analyzed. RESULTS: There were total 71 cases included in the study. Thirty one in T-tube group and 40 in primary closure group. T-tube was removed in most of the cases after three weeks where as average time of drain removal in primary closure group is 5.79 +/-1.79 days. Incidence of retained stone was equal in each group. Major complication in T-tube group is biliary peritonitis in four patients at the time of T-tube removal whereas none of the patient from primary closure group suffered from such major complication. CONCLUSIONS: Primary closure after the common bile duct exploration is safe and it helps to avoid the morbidities related to T-tube. Keywords: Choledocholithiasis, Primary closure, retained stone, T-tube, Ureterorenoscope.

Feasibility and Safety of Vascular Closure Devices in an Antegrade Approach to Either the Common Femoral Artery or the Superficial Femoral Artery

Energy Technology Data Exchange (ETDEWEB)

Gutzeit, Andreas, E-mail: andreas.gutzeit@ksw.ch; Schie, Bram van, E-mail: Bram.vanschie@hotmail.com; Schoch, Eric, E-mail: eric.schoch@ksw.ch [Cantonal Hospital Winterthur, Department of Radiology (Switzerland); Hergan, Klaus, E-mail: k.hergan@salk.at [Paracelsus Medical University Salzburg, Department of Radiology (Austria); Graf, Nicole, E-mail: graf@biostatistics.ch; Binkert, Christoph A., E-mail: christoph.binkert@ksw.ch [Cantonal Hospital Winterthur, Department of Radiology (Switzerland)

2012-10-15

Introduction: The purpose of the present study was to analyze complications following antegrade puncture of the common femoral artery (CFA) and the superficial femoral artery (SFA) using vascular closure systems (VCS). Methods: A single-center, retrospective study was performed after obtaining approval from the institutional review board and informed consent from all patients. At our center, the CFA or SFA are used for arterial access. All patients were evaluated clinically on the same day. If there was any suspicion of an access site problem, Duplex ultrasound was performed. Results: Access location was the CFA in 50 patients and the SFA in 130 patients. The sheath size ranged from 4F to 10F. Two patients had to be excluded because of lack of follow-up. Successful hemostasis was achieved in 162 of 178 cases (91 %). The following complications were observed in 16 patients (8.9 %): 4 pseudoaneurysms (2.2 %), 11 hematomas (6.2 %), and 1 vascular occlusion (0.5 %). The two pseudoaneurysms healed spontaneously, in one case an ultrasound-guided thrombin injection was performed, and one aneurysm was compressed manually. No further medical therapy was needed for the hematomas. The one vascular occlusion was treated immediately with angioplasty using a contralateral approach. No significant difference was noted between the CFA and the SFA group with respect to complications (p = 1.000). Conclusions: The use of closure devices for an antegrade approach up to 10F is feasible and safe. No differences in low complication rates were observed between CFA and SFA.

Feasibility and Safety of Vascular Closure Devices in an Antegrade Approach to Either the Common Femoral Artery or the Superficial Femoral Artery

International Nuclear Information System (INIS)

Gutzeit, Andreas; Schie, Bram van; Schoch, Eric; Hergan, Klaus; Graf, Nicole; Binkert, Christoph A.

2012-01-01

Introduction: The purpose of the present study was to analyze complications following antegrade puncture of the common femoral artery (CFA) and the superficial femoral artery (SFA) using vascular closure systems (VCS). Methods: A single-center, retrospective study was performed after obtaining approval from the institutional review board and informed consent from all patients. At our center, the CFA or SFA are used for arterial access. All patients were evaluated clinically on the same day. If there was any suspicion of an access site problem, Duplex ultrasound was performed. Results: Access location was the CFA in 50 patients and the SFA in 130 patients. The sheath size ranged from 4F to 10F. Two patients had to be excluded because of lack of follow-up. Successful hemostasis was achieved in 162 of 178 cases (91 %). The following complications were observed in 16 patients (8.9 %): 4 pseudoaneurysms (2.2 %), 11 hematomas (6.2 %), and 1 vascular occlusion (0.5 %). The two pseudoaneurysms healed spontaneously, in one case an ultrasound-guided thrombin injection was performed, and one aneurysm was compressed manually. No further medical therapy was needed for the hematomas. The one vascular occlusion was treated immediately with angioplasty using a contralateral approach. No significant difference was noted between the CFA and the SFA group with respect to complications (p = 1.000). Conclusions: The use of closure devices for an antegrade approach up to 10F is feasible and safe. No differences in low complication rates were observed between CFA and SFA.

Techniques for Abdominal Wall Closure after Damage Control Laparotomy: From Temporary Abdominal Closure to Early/Delayed Fascial Closure—A Review

Directory of Open Access Journals (Sweden)

Qian Huang

2016-01-01

Full Text Available Open abdomen (OA has been an effective treatment for abdominal catastrophes in traumatic and general surgery. However, management of patients with OA remains a formidable task for surgeons. The central goal of OA is closure of fascial defect as early as is clinically feasible without precipitating abdominal compartment syndrome. Historically, techniques such as packing, mesh, and vacuum-assisted closure have been developed to assist temporary abdominal closure, and techniques such as components separation, mesh-mediated traction, bridging fascial defect with permanent synthetic mesh, or biologic mesh have also been attempted to achieve early primary fascial closure, either alone or in combined use. The objective of this review is to present the challenges of these techniques for OA with a goal of early primary fascial closure, when the patient’s physiological condition allows.

Percutaneous closure of patent ductus arteriosus via internal jugular vein in patient with interrupted inferior vena cava

Directory of Open Access Journals (Sweden)

Patel Nehal

2009-01-01

Full Text Available Transcatheter closure of patent ductus arteriosus (PDA using various occluders and coils via femoral vein is a well established therapeutic option. However, in patients with interrupted inferior vena cava (IVC it is not feasible to close the PDA percutaneously using traditional methods. We present a nine-year-old girl with IVC interruption in whom percutaneous closure of PDA was successfully accomplished via the transjugular approach.

Factors affecting closure of a temporary stoma.

Science.gov (United States)

Taylor, Claire; Varma, Sarah

2012-01-01

The purpose of the study was to examine time to reversal of a temporary ostomy, reasons for delayed closure, and patient satisfaction with the scheduling of their closure and related hospital care. Cross-sectional, descriptive study. The target population comprised patients who underwent creation of a temporary ostomy and reversal surgery within one National Health System Hospital Trust in the United Kingdom. The population served by this Trust are ethnically and socioeconomically diverse, predominantly living in urban areas around Greater London. Sixty-one persons who met inclusion criteria were identified. A two-step analytical process was undertaken. First, a literature review examining incidence and causes of delayed stoma closure was undertaken. Second, a postal survey of all patients who had had their stoma closed in 2009 was conducted. Respondents were allowed 2 weeks to complete and return the questionnaire. The survey instrument was developed locally and subjected to content validation using ostomy patients, surgical and nursing colleagues. It consisted of 9 questions querying time from original surgery to closure, reasons for delaying closure surgery beyond 12 weeks, and satisfaction with care. Twenty-seven patients returned their questionnaires, indicating they consented to participate; a response rate of 44%. Half of the respondents (n = 14 [52%]) underwent closure surgery within 6 months of stoma formation; the remaining 48% waited more than 6 months (median: 6.5 months, range: 1.5-26 months). Thirteen patients (48%) reported a delay in receiving their stoma closure; the main reason cited was the need for a course of adjuvant postoperative chemotherapy. Three quarters of respondents (22 [74%]) were satisfied with the overall care they received. Findings from this study suggest that stoma closure may be associated with fewest complications if performed before 12 weeks.

Early decision-analytic modeling - a case study on vascular closure devices.

Science.gov (United States)

Brandes, Alina; Sinner, Moritz F; Kääb, Stefan; Rogowski, Wolf H

2015-10-27

As economic considerations become more important in healthcare reimbursement, decisions about the further development of medical innovations need to take into account not only medical need and potential clinical effectiveness, but also cost-effectiveness. Already early in the innovation process economic evaluations can support decisions on development in specific indications or patient groups by anticipating future reimbursement and implementation decisions. One potential concept for early assessment is value-based pricing. The objective is to assess the feasibility of value-based pricing and product design for a hypothetical vascular closure device in the pre-clinical stage which aims at decreasing bleeding events. A deterministic decision-analytic model was developed to estimate the cost-effectiveness of established vascular closure devices from the perspective of the Statutory Health Insurance system. To identify early benchmarks for pricing and product design, three strategies of determining the product's value are explored: 1) savings from complications avoided by the new device; 2) valuation of the avoided complications based on an assumed willingness-to-pay-threshold (the efficiency frontier approach); 3) value associated with modifying the care pathways within which the device would be applied. Use of established vascular closure devices is dominated by manual compression. The hypothetical vascular closure device reduces overall complication rates at higher costs than manual compression. Maximum cost savings of only about €4 per catheterization could be realized by applying the hypothetical device. Extrapolation of an efficiency frontier is only possible for one subgroup where vascular closure devices are not a dominated strategy. Modifying care in terms of same-day discharge of patients treated with vascular closure devices could result in cost savings of €400-600 per catheterization. It was partially feasible to calculate value-based prices for the

Corporate strategy and viable future land use: Planning for closure from the outset of mining

International Nuclear Information System (INIS)

Warhurst, A.

2000-01-01

This paper provides an overview of the environmental impact of mining on viable future land use and underlines the imperative of improved environmental management and closure planning. It argues that pollution prevention, through planning for closure, can lead to cost-effective strategies for sustainable minerals development and viable future land use. This seems to be most true for greenfield sites since, generally, the earlier closure planning and pollution prevention is built into a project, the more cost-effective and environmentally benign closure will be. Further, for greenfield sites, pollution prevention techniques can be employed from the outset, at the stages of exploration and mine development, and then monitored and improved through the operation stage to closure, and can be kept in place to manage future land use. The paper discusses how global changes in the industry, following the liberalisation of investment regimes, and mergers and strategic alliances between key firms, has, by virtue of the diffusion of new technology, led to further opportunities to prevent pollution and optimise future land use through planning for closure from the outset. The objectives and components of closure plans are also reviewed as the paper draws on case studies to highlight some of the possible constraints and challenges to pollution prevention that may be faced at the level of both public policy and corporate strategy. The article concludes by suggesting a forward-looking approach to integrated environmental management and viable future land-use planning based on a dynamic model for environmental management. (author)

CIRSE Vascular Closure Device Registry

International Nuclear Information System (INIS)

Reekers, Jim A.; Müller-Hülsbeck, Stefan; Libicher, Martin; Atar, Eli; Trentmann, Jens; Goffette, Pierre; Borggrefe, Jan; Zeleňák, Kamil; Hooijboer, Pieter; Belli, Anna-Maria

2011-01-01

Purpose: Vascular closure devices are routinely used after many vascular interventional radiology procedures. However, there have been no major multicenter studies to assess the safety and effectiveness of the routine use of closure devices in interventional radiology. Methods: The CIRSE registry of closure devices with an anchor and a plug started in January 2009 and ended in August 2009. A total of 1,107 patients were included in the registry. Results: Deployment success was 97.2%. Deployment failure specified to access type was 8.8% [95% confidence interval (95% CI) 5.0–14.5] for antegrade access and 1.8% (95% CI 1.1–2.9) for retrograde access (P = 0.001). There was no difference in deployment failure related to local PVD at the access site. Calcification was a reason for deployment failure in only 5.9 cm, and two vessel occlusions. Conclusion: The conclusion of this registry of closure devices with an anchor and a plug is that the use of this device in interventional radiology procedures is safe, with a low incidence of serious access site complications. There seems to be no difference in complications between antegrade and retrograde access and other parameters.

40 CFR 267.143 - Financial assurance for closure.

Science.gov (United States)

2010-07-01

...), utilizing the certificate of insurance for closure specified at 40 CFR 264.151(e). (f) Corporate financial... 40 Protection of Environment 26 2010-07-01 2010-07-01 false Financial assurance for closure. 267... PERMIT Financial Requirements § 267.143 Financial assurance for closure. The owner or operator must...

Tubular closure mechanism

International Nuclear Information System (INIS)

Kalen, D.D.; Mitchem, J.W.

1982-01-01

This invention relates to a closure mechanism for tubular irradiation surveillance specimen assembly holder used in nuclear reactors. The closure mechanism is composed of a latching member which includes a generally circular chamber with a plurality of elongated latches depending therefrom. The latching member circumscribes part of an actuator member which is disposed within the latching member so as to be axially movable. The axial movement of the actuator actuates positioning of the latches between positions in which the latches are locked and secured within the actuator member. Means, capable of being remotely manipulated, are provided to move the actuator in order to position the latches and load the articles within the tube

Design and analysis of PCRV core cavity closure

International Nuclear Information System (INIS)

Lee, T.T.; Schwartz, A.A.; Koopman, D.C.A.

1980-05-01

Design requirements and considerations for a core cavity closure which led to the choice of a concrete closure with a toggle hold-down as the design for the Gas-Cooled Fast Breeder Reactor (GCFR) plant are discussed. A procedure for preliminary stress analysis of the closure by means of a three-dimensional finite element method is described. A limited parametric study using this procedure indicates the adequacy of the present closure design and the significance of radial compression developed as a result of inclined support reaction

40 CFR 265.280 - Closure and post-closure.

Science.gov (United States)

2010-07-01

... contaminants caused by wind erosion; and (4) Compliance with § 265.276 concerning the growth of food-chain... and post-closure care objectives of paragraph (a) of this section: (1) Type and amount of hazardous..., including amount, frequency, and pH of precipitation; (5) Geological and soil profiles and surface and...

Airport Movement Area Closure Planner, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — This SBIR research develops an automation tool improving temporary and permanent runway closure management. The Movement Area Closure Planner (MACP) provides airport...

Numerical approaches to time evolution of complex quantum systems

International Nuclear Information System (INIS)

Fehske, Holger; Schleede, Jens; Schubert, Gerald; Wellein, Gerhard; Filinov, Vladimir S.; Bishop, Alan R.

2009-01-01

We examine several numerical techniques for the calculation of the dynamics of quantum systems. In particular, we single out an iterative method which is based on expanding the time evolution operator into a finite series of Chebyshev polynomials. The Chebyshev approach benefits from two advantages over the standard time-integration Crank-Nicholson scheme: speedup and efficiency. Potential competitors are semiclassical methods such as the Wigner-Moyal or quantum tomographic approaches. We outline the basic concepts of these techniques and benchmark their performance against the Chebyshev approach by monitoring the time evolution of a Gaussian wave packet in restricted one-dimensional (1D) geometries. Thereby the focus is on tunnelling processes and the motion in anharmonic potentials. Finally we apply the prominent Chebyshev technique to two highly non-trivial problems of current interest: (i) the injection of a particle in a disordered 2D graphene nanoribbon and (ii) the spatiotemporal evolution of polaron states in finite quantum systems. Here, depending on the disorder/electron-phonon coupling strength and the device dimensions, we observe transmission or localisation of the matter wave.

Physical modeling and numerical simulation of V-die forging ingot with central void

DEFF Research Database (Denmark)

Christiansen, Peter; Hattel, Jesper Henri; Bay, Niels

2014-01-01

Numerical simulation and physical modeling performed on small-scale ingots made from pure lead, having a hole drilled through their centerline to mimic porosity, are utilized to characterize the deformation mechanics of a single open die forging compression stage and to identify the influence...... of the lower V-die angle on porosity closure and forging load requirements of large cast ingots. Results show that a lower V-die angle of 120 provides the best closure of centerline porosity without demanding the highest forging loads or developing unreasonably asymmetric shapes that may create difficulties...... in multi-stage open die forging procedures....

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

Energy Technology Data Exchange (ETDEWEB)

Stiehler, Johannes

1995-12-15

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

Left ventricular remodeling and change of systolic function after closure of patent ductus arteriosus in adults: device and surgical closure.

Science.gov (United States)

Jeong, Young-Hoon; Yun, Tae-Jin; Song, Jong-Min; Park, Jung-Jun; Seo, Dong-Man; Koh, Jae-Kon; Lee, Se-Whan; Kim, Mi-Jeong; Kang, Duk-Hyun; Song, Jae-Kwan

2007-09-01

Left ventricular (LV) remodeling and predictors of LV systolic function late after closure of patent ductus arteriosus (PDA) in adults remain to be clearly demonstrated. In 45 patients with PDA, including 28 patients who received successful occlusion using the Amplatzer device (AD group) (AGA, Golden Valley, MN) and 17 patients who received surgical closure (OP group), echocardiography studies were performed before closure and 1 day (AD group) or within 7 days (OP group) after closure, and then were repeated at > or = 6 months (17 +/- 13 months). In both groups, LV ejection fraction (EF) and end-diastolic volume index were significantly decreased immediately after closure, whereas end-systolic volume index did not change. During the long-term follow-up period, end-systolic as well as end-diastolic volume indices decreased significantly in both groups and LV EF recovered compared to the immediate postclosure state. However, LV EF remained low compared to the preclosure state. Five patients (11.1%) including 3 patients in the AD group and 2 patients in the OP group showed persistent late LV systolic dysfunction (EF or = 62% had a sensitivity of 72% and a specificity of 83% for predicting late normal LV EF after closure. Left ventricular EF remains low late after PDA closure compared with preclosure state in adults. Preclosure LV EF is the best index to predict late postclosure LV EF.

Single-site neural tube closure in human embryos revisited.

Science.gov (United States)

de Bakker, Bernadette S; Driessen, Stan; Boukens, Bastiaan J D; van den Hoff, Maurice J B; Oostra, Roelof-Jan

2017-10-01

Since the multi-site closure theory was first proposed in 1991 as explanation for the preferential localizations of neural tube defects, the closure of the neural tube has been debated. Although the multi-site closure theory is much cited in clinical literature, single-site closure is most apparent in literature concerning embryology. Inspired by Victor Hamburgers (1900-2001) statement that "our real teacher has been and still is the embryo, who is, incidentally, the only teacher who is always right", we decided to critically review both theories of neural tube closure. To verify the theories of closure, we studied serial histological sections of 10 mouse embryos between 8.5 and 9.5 days of gestation and 18 human embryos of the Carnegie collection between Carnegie stage 9 (19-21 days) and 13 (28-32 days). Neural tube closure was histologically defined by the neuroepithelial remodeling of the two adjoining neural fold tips in the midline. We did not observe multiple fusion sites in neither mouse nor human embryos. A meta-analysis of case reports on neural tube defects showed that defects can occur at any level of the neural axis. Our data indicate that the human neural tube fuses at a single site and, therefore, we propose to reinstate the single-site closure theory for neural tube closure. We showed that neural tube defects are not restricted to a specific location, thereby refuting the reasoning underlying the multi-site closure theory. Clin. Anat. 30:988-999, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Moment Closure for the Stochastic Logistic Model

National Research Council Canada - National Science Library

Singh, Abhyudai; Hespanha, Joao P

2006-01-01

..., which we refer to as the moment closure function. In this paper, a systematic procedure for constructing moment closure functions of arbitrary order is presented for the stochastic logistic model...

Comparison of cost-effectiveness and postoperative outcome of device closure and open surgery closure techniques for treatment of patent ductus arteriosus.

Science.gov (United States)

Ahmadi, Alireza; Sabri, Mohammadreza; Bigdelian, Hamid; Dehghan, Bahar; Gharipour, Mojgan

2014-01-01

Various devices have been recently employed for percutaneous closure of the patent ductus arteriosus (PDA). Although the high effectiveness of device closure techniques has been clearly determined, a few studies have focused on the cost-effectiveness and also postoperative complications of these procedures in comparison with open surgery. The present study aimed to evaluate the clinical outcome and cost-effectiveness of PDA occlusion by Amplatzer and coil device in comparisong with open surgery. In this cross-sectional study, a randomized sample of 201 patients aged 1 month to 16 years (105 patients with device closure and 96 patients with surgical closure) was selected. The ratio of total pulmonary blood flow to total systemic blood flow, the Qp/Qs ratio, was measured using a pulmonary artery catheter. The cost analysis included direct medical care costs associated with device implantation and open surgery, as well as professional fees. All costs were calculated in Iranian Rials and then converted to US dollars. There was no statistical difference in mean Qp/Qs ratio before the procedure between the device closure group and the open surgery group (2.1 ± 0.7 versus 1.7 ± 0.6, P = 0.090). The mean measured costs were overall higher in the device closure group than in open closure group (948.87 ± 548.76 US$ versus 743.70 ± 696.91 US$, P gender (Standardized Beta = 0.160, P = 0.031). PDA closure with the Amplatzer ductal occluder (1053.05 ± 525.73 US$) or with Nit-Occlud coils (PFM) (912.73 ± 565.94 US$, P < 0.001) was more expensive than that via open surgery. However, the Cook detachable spring coils device closure (605.65 ± 194.62 US$, P = 0.650) had a non-significant cost difference with open surgery. No event was observed in the device closure group regarding in-hospital mortality or morbidity; however, in another group, 2 in-hospital deaths occurred, two patients experienced pneumonia and seizure, and one suffered electrolyte abnormalities including

Mass extraction container closure integrity physical testing method development for parenteral container closure systems.

Science.gov (United States)

Yoon, Seung-Yil; Sagi, Hemi; Goldhammer, Craig; Li, Lei

2012-01-01

Container closure integrity (CCI) is a critical factor to ensure that product sterility is maintained over its entire shelf life. Assuring the CCI during container closure (C/C) system qualification, routine manufacturing and stability is important. FDA guidance also encourages industry to develop a CCI physical testing method in lieu of sterility testing in a stability program. A mass extraction system has been developed to check CCI for a variety of container closure systems such as vials, syringes, and cartridges. Various types of defects (e.g., glass micropipette, laser drill, wire) were created and used to demonstrate a detection limit. Leakage, detected as mass flow in this study, changes as a function of defect length and diameter. Therefore, the morphology of defects has been examined in detail with fluid theories. This study demonstrated that a mass extraction system was able to distinguish between intact samples and samples with 2 μm defects reliably when the defect was exposed to air, water, placebo, or drug product (3 mg/mL concentration) solution. Also, it has been verified that the method was robust, and capable of determining the acceptance limit using 3σ for syringes and 6σ for vials. Sterile products must maintain their sterility over their entire shelf life. Container closure systems such as those found in syringes and vials provide a seal between rubber and glass containers. This seal must be ensured to maintain product sterility. A mass extraction system has been developed to check container closure integrity for a variety of container closure systems such as vials, syringes, and cartridges. In order to demonstrate the method's capability, various types of defects (e.g., glass micropipette, laser drill, wire) were created in syringes and vials and were tested. This study demonstrated that a mass extraction system was able to distinguish between intact samples and samples with 2 μm defects reliably when the defect was exposed to air, water

105-DR Large Sodium Fire Facility closure activities evaluation report

International Nuclear Information System (INIS)

Adler, J.G.

1996-01-01

This report evaluates the closure activities at the 105-DR Large Sodium Fire Facility. The closure activities discussed include: the closure activities for the structures, equipment, soil, and gravel scrubber; decontamination methods; materials made available for recycling or reuse; and waste management. The evaluation compares these activities to the regulatory requirements and closure plan requirements. The report concludes that the areas identified in the closure plan can be clean closed

A nonlinear structural subgrid-scale closure for compressible MHD. I. Derivation and energy dissipation properties

Energy Technology Data Exchange (ETDEWEB)

Vlaykov, Dimitar G., E-mail: Dimitar.Vlaykov@ds.mpg.de [Institut für Astrophysik, Universität Göttingen, Friedrich-Hund-Platz 1, D-37077 Göttingen (Germany); Max-Planck-Institut für Dynamik und Selbstorganisation, Am Faßberg 17, D-37077 Göttingen (Germany); Grete, Philipp [Institut für Astrophysik, Universität Göttingen, Friedrich-Hund-Platz 1, D-37077 Göttingen (Germany); Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, D-37077 Göttingen (Germany); Schmidt, Wolfram [Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112, D-21029 Hamburg (Germany); Schleicher, Dominik R. G. [Departamento de Astronomía, Facultad Ciencias Físicas y Matemáticas, Universidad de Concepción, Av. Esteban Iturra s/n Barrio Universitario, Casilla 160-C (Chile)

2016-06-15

Compressible magnetohydrodynamic (MHD) turbulence is ubiquitous in astrophysical phenomena ranging from the intergalactic to the stellar scales. In studying them, numerical simulations are nearly inescapable, due to the large degree of nonlinearity involved. However, the dynamical ranges of these phenomena are much larger than what is computationally accessible. In large eddy simulations (LESs), the resulting limited resolution effects are addressed explicitly by introducing to the equations of motion additional terms associated with the unresolved, subgrid-scale dynamics. This renders the system unclosed. We derive a set of nonlinear structural closures for the ideal MHD LES equations with particular emphasis on the effects of compressibility. The closures are based on a gradient expansion of the finite-resolution operator [W. K. Yeo (CUP, 1993)] and require no assumptions about the nature of the flow or magnetic field. Thus, the scope of their applicability ranges from the sub- to the hyper-sonic and -Alfvénic regimes. The closures support spectral energy cascades both up and down-scale, as well as direct transfer between kinetic and magnetic resolved and unresolved energy budgets. They implicitly take into account the local geometry, and in particular, the anisotropy of the flow. Their properties are a priori validated in Paper II [P. Grete et al., Phys. Plasmas 23, 062317 (2016)] against alternative closures available in the literature with respect to a wide range of simulation data of homogeneous and isotropic turbulence.

Storage shaft definitive closure plug and method

International Nuclear Information System (INIS)

Dardaine, M.

1992-01-01

A definitive closure plug system for radioactive waste storage at any deepness, is presented. The inherent weight of the closure materials is used to set in the plug: these materials display an inclined sliding surface in such a way that when the closure material rests on a stable surface of the shaft storage materials, the relative sliding of the different materials tends to spread them towards the shaft internal wall so as to completely occlude the shaft

Use of Suture-Mediated Closure Device in Percutaneous Direct Carotid Puncture During Chimney-Thoracic Endovascular Aortic Repair

International Nuclear Information System (INIS)

Chan, Gabriel; Quek, Lawrence Hwee Han; Tan, Glenn Leong Wei; Pua, Uei

2016-01-01

BackgroundInsertion of a carotid chimney graft during thoracic endovascular aortic repair (Ch-TEVAR) is a recognized technique to extend the proximal landing zone into the aortic arch in the treatment of thoracic aortic disease. Conventional technique requires surgical exposure of the carotid artery for insertion of the carotid chimney graft.MethodologyWe describe our experience in the use of a suture-mediated closure device in percutaneous Ch-TEVAR in four patients.ResultsSuccessful hemostasis was achieved in all four patients. No complications related to the carotid puncture were recorded.ConclusionWe conclude that using suture-mediated closure device for carotid closure appears feasible and deserves further studies as a potential alternative to conventional surgical approach.

Use of Suture-Mediated Closure Device in Percutaneous Direct Carotid Puncture During Chimney-Thoracic Endovascular Aortic Repair

Energy Technology Data Exchange (ETDEWEB)

Chan, Gabriel, E-mail: dr.changabriel@gmail.com; Quek, Lawrence Hwee Han, E-mail: lawrence-quek@ttsh.com.sg [Tan Tock Seng Hospital, Department of Diagnostic Radiology (Singapore); Tan, Glenn Leong Wei, E-mail: glenn-tan@ttsh.com.sg [Tan Tock Seng Hospital, Department of General Surgery (Singapore); Pua, Uei, E-mail: druei@yahoo.com [Tan Tock Seng Hospital, Department of Diagnostic Radiology (Singapore)

2016-07-15

BackgroundInsertion of a carotid chimney graft during thoracic endovascular aortic repair (Ch-TEVAR) is a recognized technique to extend the proximal landing zone into the aortic arch in the treatment of thoracic aortic disease. Conventional technique requires surgical exposure of the carotid artery for insertion of the carotid chimney graft.MethodologyWe describe our experience in the use of a suture-mediated closure device in percutaneous Ch-TEVAR in four patients.ResultsSuccessful hemostasis was achieved in all four patients. No complications related to the carotid puncture were recorded.ConclusionWe conclude that using suture-mediated closure device for carotid closure appears feasible and deserves further studies as a potential alternative to conventional surgical approach.

Laser peripheral iridoplasty for angle-closure.

Science.gov (United States)

Ng, Wai Siene; Ang, Ghee Soon; Azuara-Blanco, Augusto

2012-02-15

Angle-closure glaucoma is a leading cause of irreversible blindness in the world. Treatment is aimed at opening the anterior chamber angle and lowering the IOP with medical and/or surgical treatment (e.g. trabeculectomy, lens extraction). Laser iridotomy works by eliminating pupillary block and widens the anterior chamber angle in the majority of patients. When laser iridotomy fails to open the anterior chamber angle, laser iridoplasty may be recommended as one of the options in current standard treatment for angle-closure. Laser peripheral iridoplasty works by shrinking and pulling the peripheral iris tissue away from the trabecular meshwork. Laser peripheral iridoplasty can be used for crisis of acute angle-closure and also in non-acute situations.   To assess the effectiveness of laser peripheral iridoplasty in the treatment of narrow angles (i.e. primary angle-closure suspect), primary angle-closure (PAC) or primary angle-closure glaucoma (PACG) in non-acute situations when compared with any other intervention. In this review, angle-closure will refer to patients with narrow angles (PACs), PAC and PACG. We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2011, Issue 12), MEDLINE (January 1950 to January 2012), EMBASE (January 1980 to January 2012), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to January 2012), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). There were no date or language restrictions in the electronic searches for trials. The electronic databases were last searched on 5 January 2012. We included only randomised controlled trials (RCTs) in this review. Patients with narrow angles, PAC or PACG were eligible. We excluded studies that included only patients with acute presentations

Numerical simulation of plasma vertical position stabilization in ITER

International Nuclear Information System (INIS)

Astapkovich, A.M.; Sadakov, S.N.

1992-01-01

The paper deals with numerical simulation of plasma vertical position stabilization in ITER. The calculations are performed using EDDY C-2 code by the method of direct numerical simulation of transient electromagnetic processes taking into account the evolution of plasma position, cross-section shape and full plasma current. When simulating free vertical plasma drift in ITER with twin passive stabilization loops, it was shown that account of the effects of cross-section deformation and plasma current alternations results in almost two fold degradation of passive stabilization parameters as compared to the calculations for 'rigid displacement' model. In terms of methodology, the account of the effects of cross section deformation and plasma current alternations requires clarification of the definitions for reverse increment of vertical instability and for stability margin coefficient. The simulation of plasma pinch return to equilibrium position after the closure of control coils allows to assess the required parameters of active control system and demonstrate the effect of screen current reverse in twin loops. The obtained results were used to develop the ITER conceptual design and affected the choice of the concept of twin passive loops and new positron of control coils as the basis approaches. 11 refs.; 12 figs.; 1 tab

Streamlined approach for environmental restoration closure report for Corrective Action Unit 452: Historical underground storage tank release sites, Nevada Test Site, Nevada

International Nuclear Information System (INIS)

1998-04-01

This report addresses the site characterization of three historical underground storage tank (UST) petroleum hydrocarbon release sites identified as 25-3101-1, 25-3102-3, and 25-3152-1. The sites are located within the Nevada Test Site in Area 25 at Buildings 3101, 3102, and 3152. The characterization was completed to support administrative closure of the sites. Characterization was completed using drilling equipment to delineate the extent of hydrocarbon impact. Clean closure had been previously attempted at each of these sites using backhoe equipment without success due to adjacent structures, buried utilities, or depth restrictions associated with each site. Although the depth and extent of hydrocarbon impact was determined to be too extensive for clean closure, it was verified through drilling that the sites should be closed through an administrative closure. The Nevada Administrative Code ''A Through K'' evaluation completed for each site supports that there is no significant risk to human health or the environment from the impacted soils remaining at each site

The potential migration effect of rural hospital closures

DEFF Research Database (Denmark)

Sørensen, Jens Fyhn Lykke

2008-01-01

to out-migration, although the hypothetical way of questioning leaves uncertainty about the actual scale of out-migration. Child families appear to be the most likely out-migrants. Elderly people may be hardest hit by a hospital closure, being most reliant on health care and least inclined to move away.......Rural hospital closures are high on the current health care agenda in Denmark. One raised concern is that rural hospital closures may further decrease population numbers in rural areas, as closures may induce some residents to move away from affected areas, i.e. closer to health care services...

Closure of a unique mixed waste storage canal at the Dept. of Energy's Oak Ridge National Laboratory (ORNL)

International Nuclear Information System (INIS)

Greer, J.K. Jr.; Etheridge, J.T.; Thompson, W.T.

1994-01-01

At the Department of Energy's (DOE's) Oak Ridge National Laboratory (ORNL) a unique closure was accomplished for a storage canal that contained both hazardous chemical contaminants controlled by the Resource Conservation and Recovery Act (RCRA), and radioactive contaminants controlled by the Atomic Energy Act (AEA). During 1991 and 1992, after approvals were received from the DOE and the Tennessee Department of Environment and Conservation (TDEC), subcontractors to DOE's Construction Manager were mobilized and remote controlled equipment was operated on site to remove the RCRA and radioactive contamination (referred to hereafter as mixed wastes) from the 3001 Storage Canal at ORNL. After numerous open-quotes surprisesclose quotes during the removal activities, each requiring problem resolution and approvals from DOE and TDEC, the canal closure was completed in September 1992 and final closure certification was submitted to TDEC in October 1992. The following discussion describes the learning experiences that ORNL and DOE acquired from a RCRA closure project for a mixed waste storage canal containing high radiation levels. The project was successful, especially since worker exposures were minimized, but was lengthy, requiring 30 months from notification of a leak in the canal until final demobilization of the subcontractor, and expensive to complete (total overall cost of $3 million)

304 Concretion facility closure plan

International Nuclear Information System (INIS)

1990-04-01

The Hanford Site, located northwest of Richland, Washington, houses reactors, chemical-separation systems, and related facilities used for the production of special nuclear materials. The 300 Area of the Hanford Site contains reactor fuel manufacturing facilities and several research and development laboratories. Recyclable scrap uranium Zircaloy-2 and copper silicon alloy, uranium-titanium alloy, beryllium/Zircaloy-2 alloy, and Zircaloy-2 chips and fines were secured in concrete billets in the 304 Concretion Facility, located in the 300 Area. The beryllium/Zircaloy-2 alloy and Zircaloy-2 chips and fines are designated as low-level radioactive mixed waste (LLRMW) with the characteristic of ignitability. The concretion process reduced the ignitability of the fines and chips for safe storage and shipment. This process has been discontinued and the 304 Concretion Facility is now undergoing closure as defined in the Resource Conservation and Recovery Act of 1976 (RCRA). This closure plan presents a description of the facility, the history of materials and wastes managed, and the procedures that will be followed to close the 304 Concretion Facility (304 Facility). Clean closure of the 304 Facility is the proposed method for closure of the facility. Justification for this proposal is presented. 15 refs., 22 figs., 4 tabs

CIRSE Vascular Closure Device Registry

Science.gov (United States)

Müller-Hülsbeck, Stefan; Libicher, Martin; Atar, Eli; Trentmann, Jens; Goffette, Pierre; Borggrefe, Jan; Zeleňák, Kamil; Hooijboer, Pieter; Belli, Anna-Maria

2010-01-01

Purpose Vascular closure devices are routinely used after many vascular interventional radiology procedures. However, there have been no major multicenter studies to assess the safety and effectiveness of the routine use of closure devices in interventional radiology. Methods The CIRSE registry of closure devices with an anchor and a plug started in January 2009 and ended in August 2009. A total of 1,107 patients were included in the registry. Results Deployment success was 97.2%. Deployment failure specified to access type was 8.8% [95% confidence interval (95% CI) 5.0–14.5] for antegrade access and 1.8% (95% CI 1.1–2.9) for retrograde access (P = 0.001). There was no difference in deployment failure related to local PVD at the access site. Calcification was a reason for deployment failure in only 5.9 cm, and two vessel occlusions. Conclusion The conclusion of this registry of closure devices with an anchor and a plug is that the use of this device in interventional radiology procedures is safe, with a low incidence of serious access site complications. There seems to be no difference in complications between antegrade and retrograde access and other parameters. PMID:20981425

200 West Ash Pit Demolition Site closure plan

International Nuclear Information System (INIS)

1992-11-01

The Hanford Facility is owned by the US Government and operated by the US Department of Energy, Richland Field Office. Dangerous waste and mixed waste (containing both radioactive and dangerous components) are managed and produced on the Hanford Facility. Westinghouse Hanford Company is a major contractor to the US Department of Energy, Richland Field Office and serves as cooperator of the 200 West Ash Pit Demolition Site, the unit addressed in this closure plan. The 200 West Ash Pit Demolition Site Closure Plan consists of a Part A Permit Application (Revision 3) and a closure plan. An explanation of the Part A Permit Application revision is provided at the beginning of the Part A section. The closure plan consists of nine chapters and three appendices. This 200 West Ash Pit Demolition Site Closure Plan submittal contains information current as of October 15, 1992

Reinvestigation into Closure Predictions of Room D at the Waste Isolation Pilot Plant

Energy Technology Data Exchange (ETDEWEB)

Reedlunn, Benjamin [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2016-10-01

Room D was an in-situ, isothermal, underground experiment conducted at theWaste Isolation Pilot Plant between 1984 and 1991. The room was carefully instrumented to measure the horizontal and vertical closure immediately upon excavation and for several years thereafter. Early finite element simulations of salt creep around Room D under predicted the vertical closure by 4.5×, causing investigators to explore a series of changes to the way Room D was modeled. Discrepancies between simulations and measurements were resolved through a series of adjustments to model parameters, which were openly acknowledged in published reports. Interest in Room D has been rekindled recently by the U.S./German Joint Project III and Project WEIMOS, which seek to improve the predictions of rock salt constitutive models. Joint Project participants calibrate their models solely against laboratory tests, and benchmark the models against underground experiments, such as room D. This report describes updating legacy Room D simulations to today’s computational standards by rectifying several numerical issues. Subsequently, the constitutive model used in previous modeling is recalibrated two different ways against a suite of new laboratory creep experiments on salt extracted from the repository horizon of the Waste Isolation Pilot Plant. Simulations with the new, laboratory-based, calibrations under predict Room D vertical closure by 3.1×. A list of potential improvements is discussed.

Reinvestigation into Closure Predictions of Room D at the Waste Isolation Pilot Plant

Energy Technology Data Exchange (ETDEWEB)

Reedlunn, Benjamin [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2016-09-27

Room D was an in-situ, isothermal, underground experiment conducted at the Waste Isolation Pilot Plant between 1984 and 1991. The room was carefully instrumented to measure the horizontal and vertical closure immediately upon excavation and for several years thereafter. Early finite element simulations of salt creep around Room D under-predicted the vertical closure by 4.5×, causing investigators to explore a series of changes to the way Room D was modeled. Discrepancies between simulations and measurements were resolved through a series of adjustments to model parameters, which were openly acknowledged in published reports. Interest in Room D has been rekindled recently by the U.S./German Joint Project III and Project WEIMOS, which seek to improve the predictions of rock salt constitutive models. Joint Project participants calibrate their models solely against laboratory tests, and benchmark the models against underground experiments, such as room D. This report describes updating legacy Room D simulations to today’s computational standards by rectifying several numerical issues. Subsequently, the constitutive model used in previous modeling is recalibrated two different ways against a suite of new laboratory creep experiments on salt extracted from the repository horizon of the Waste Isolation Pilot Plant. Simulations with the new, laboratory-based, calibrations under-predict Room D vertical closure by 3.1×. A list of potential improvements is discussed.

A successful environmental remediation program closure and post-closure activities (CAPCA) Y-12 Plant, Oak Ridge, Tennessee

International Nuclear Information System (INIS)

Bowers, M.H.

1991-01-01

The Resource Conservation and Recovery Act (RCRA) closure of eleven waste management units at the Department of Energy's (DOE's) Oak Ridge Y-12 Plant is nearing completion. The Oak Ridge Y-12 Plant is managed by Martin Marietta Energy Systems, Inc. for the US Department of Energy under Contract DE-AC05-84OR21400. The Closure and Post Closure Program (CAPCA) has been accomplished on an accelerated schedule through the efforts of a dedicated team from several organizations. This paper relates experience gained from the program that can be of benefit on other DOE environmental remediation projects. Technical design and construction aspects, as well as project management considerations, are discussed

Evaluation of Container Closure System Integrity for Frozen Storage Drug Products.

Science.gov (United States)

Nieto, Alejandra; Roehl, Holger; Brown, Helen; Nikoloff, Jonas; Adler, Michael; Mahler, Hanns-Christian

2016-01-01

Sometimes, drug product for parenteral administration is stored in a frozen state (e.g., -20 °C or -80 °C), particularly during early stages of development of some biotech molecules in order to provide sufficient stability. Shipment of frozen product could potentially be performed in the frozen state, yet possibly at different temperatures, for example, using dry ice (-80 °C). Container closure systems of drug products usually consist of a glass vial, rubber stopper, and an aluminum crimped cap. In the frozen state, the glass transition temperature (Tg) of commonly used rubber stoppers is between -55 and -65 °C. Below their Tg, rubber stoppers are known to lose their elastic properties and become brittle, and thus potentially fail to maintain container closure integrity in the frozen state. Leaks during frozen temperature storage and transportation are likely to be transient, yet, can possibly risk container closure integrity and lead to microbial contamination. After thawing, the rubber stopper is supposed to re-seal the container closure system. Given the transient nature of the possible impact on container closure integrity in the frozen state, typical container closure integrity testing methods (used at room temperature conditions) are unable to evaluate and thus confirm container closure integrity in the frozen state. Here we present the development of a novel method (thermal physical container closure integrity) for direct assessment of container closure integrity by a physical method (physical container closure integrity) at frozen conditions, using a modified He leakage test. In this study, different container closure systems were evaluated with regard to physical container closure integrity in the frozen state to assess the suitability of vial/stopper combinations and were compared to a gas headspace method. In summary, the thermal physical container closure integrity He leakage method was more sensitive in detecting physical container closure

Considerations for closure of low-level radioactive waste engineered disposal facilities

International Nuclear Information System (INIS)

1992-01-01

Proper stabilization and closure of low-level radioactive waste disposal facilities require detailed planning during the early stages of facility development. This report provides considerations for host States, compact regions, and unaffiliated States on stabilization and closure of engineered low-level radioactive waste and mixed waste disposal facilities. A time line for planning closure activities, which identifies closure considerations to be addressed during various stages of a facility's development, is presented. Current Federal regulatory requirements and guidance for closure and post-closure are outlined. Significant differences between host State and Federal closure requirements are identified. Design features used as stabilization measures that support closure, such as waste forms and containers, backfill materials, engineered barrier systems, and site drainage systems, are described. These design features are identified and evaluated in terms of how they promote long-term site stability by minimizing water infiltration, controlling subsidence and surface erosion, and deterring intrusion. Design and construction features critical to successful closure are presented for covers and site drainage. General considerations for stabilization and closure operations are introduced. The role of performance and environmental monitoring during closure is described

Tank closure reducing grout

International Nuclear Information System (INIS)

Caldwell, T.B.

1997-01-01

A reducing grout has been developed for closing high level waste tanks at the Savannah River Site in Aiken, South Carolina. The grout has a low redox potential, which minimizes the mobility of Sr 90 , the radionuclide with the highest dose potential after closure. The grout also has a high pH which reduces the solubility of the plutonium isotopes. The grout has a high compressive strength and low permeability, which enhances its ability to limit the migration of contaminants after closure. The grout was designed and tested by Construction Technology Laboratories, Inc. Placement methods were developed by the Savannah River Site personnel

Numerical algorithm for rigid body position estimation using the quaternion approach

Science.gov (United States)

Zigic, Miodrag; Grahovac, Nenad

2017-11-01

This paper deals with rigid body attitude estimation on the basis of the data obtained from an inertial measurement unit mounted on the body. The aim of this work is to present the numerical algorithm, which can be easily applied to the wide class of problems concerning rigid body positioning, arising in aerospace and marine engineering, or in increasingly popular robotic systems and unmanned aerial vehicles. Following the considerations of kinematics of rigid bodies, the relations between accelerations of different points of the body are given. A rotation matrix is formed using the quaternion approach to avoid singularities. We present numerical procedures for determination of the absolute accelerations of the center of mass and of an arbitrary point of the body expressed in the inertial reference frame, as well as its attitude. An application of the algorithm to the example of a heavy symmetrical gyroscope is presented, where input data for the numerical procedure are obtained from the solution of differential equations of motion, instead of using sensor measurements.

Comparison of Numerical Approaches to a Steady-State Landscape Equation

Science.gov (United States)

Bachman, S.; Peckham, S.

2008-12-01

A mathematical model of an idealized fluvial landscape has been developed, in which a land surface will evolve to preserve dendritic channel networks as the surface is lowered. The physical basis for this model stems from the equations for conservation of mass for water and sediment. These equations relate the divergence of the 2D vector fields showing the unit-width discharge of water and sediment to the excess rainrate and tectonic uplift on the land surface. The 2D flow direction is taken to be opposite to the water- surface gradient vector. These notions are combined with a generalized Manning-type flow resistance formula and a generalized sediment transport law to give a closed mathematical system that can, in principle, be solved for all variables of interest: discharge of water and sediment, land surface height, vertically- averaged flow velocity, water depth, and shear stress. The hydraulic geometry equations (Leopold et. al, 1964, 1995) are used to incorporate width, depth, velocity, and slope of river channels as powers of the mean-annual river discharge. Combined, they give the unit- width discharge of the stream as a power, γ, of the water surface slope. The simplified steady-state model takes into account three components among those listed above: conservation of mass for water, flow opposite the gradient, and a slope-discharge exponent γ = -1 to reflect mature drainage networks. The mathematical representation of this model appears as a second-order hyperbolic partial differential equation (PDE) where the diffusivity is inversely proportional to the square of the local surface slope. The highly nonlinear nature of this PDE has made it very difficult to solve both analytically and numerically. We present simplistic analytic solutions to this equation which are used to test the validity of the numerical algorithms. We also present three such numerical approaches which have been used in solving the differential equation. The first is based on a

Socket sclerosis--an obstacle for orthodontic space closure?

Science.gov (United States)

Baumgaertel, Sebastian

2009-07-01

Socket sclerosis is a rare reaction to tooth extraction resulting in high-density bone in the center of the alveolar process, where, under normal circumstances, cancellous bone is to be expected. In an adult orthodontic patient, routine extractions of the mandibular first permanent bicuspids were performed, resulting in socket sclerosis and unsuccessful orthodontic space closure. Orthodontic mini-implants were inserted to augment anchorage and aid in space closure. In the presence of socket sclerosis, conventional orthodontic mechanics failed to close the extraction spaces. However, with absolute anchorage in place, space closure occurred at a nearly normal rate. After treatment, no signs of socket sclerosis were discernible on the periapical radiographs. Socket sclerosis can be an obstacle for orthodontic space closure if traditional mechanics are employed. However, mini-implant-reinforced anchorage can lead to successful space closure, resulting in complete resolution of the sclerotic sites.

Primary closure of equine laryngotomy incisions

DEFF Research Database (Denmark)

Lindegaard, C.; Karlsson, L.; Ekstrøm, Claus Thorn

2016-01-01

incision between January 1995 and June 2012 were reviewed. Horses with a laryngotomy incision closed in three layers for primary healing were included. Descriptive data on healing characteristics and complications of laryngotomy wounds were collected from the medical records and via follow......The objective was to report healing characteristics and complications after primary closure of equine laryngotomies and analyse factors potentially associated with complications. This retrospective case series of the medical records of horses (n = 180) undergoing laryngoplasty and laryngotomy...... after primary closure of equine laryngotomy incisions are infrequent and considered of minimal severity and can be performed safely when paying careful attention to the closure of the cricothyroid membrane....

Detailed design report for an operational phase panel-closure system

International Nuclear Information System (INIS)

1996-01-01

Under contract to Westinghouse Electric Corporation (Westinghouse), Waste Isolation Division (WID), IT Corporation has prepared a detailed design of a panel-closure system for the Waste Isolation Pilot Plant (WIPP). Preparation of this detailed design of an operational-phase closure system is required to support a Resource Conservation and Recovery Act (RCRA) Part B permit application and a non-migration variance petition. This report describes the detailed design for a panel-closure system specific to the WIPP site. The recommended panel-closure system will adequately isolate the waste-emplacement panels for at least 35 years. This report provides detailed design and material engineering specifications for the construction, emplacement, and interface-grouting associated with a panel-closure system at the WIPP repository, which would ensure that an effective panel-closure system is in place for at least 35 years. The panel-closure system provides assurance that the limit for the migration of volatile organic compounds (VOC) will be met at the point of compliance, the WIPP site boundary. This assurance is obtained through the inherent flexibility of the panel-closure system

Percutaneous Transcatheter PDA Device Closure in Infancy

International Nuclear Information System (INIS)

Ullah, M.; Sultan, M.; Akhtar, K.; Sadiq, N.; Akbar, H.

2014-01-01

Objective: To evaluate the results and complications associated with transcatheter closure of patent ductus arteriosus (PDA) in infants. Study Design: Quasi-experimental study. Place and Duration of Study: Paediatric Cardiology Department of Armed Forces Institute of Cardiology / National Institute of Heart Diseases (AFIC/NIHD), Rawalpindi, from December 2010 to June 2012. Methodology: Infants undergoing transcatheter device closure of PDA were included. All patients were evaluated by experienced Paediatric Cardiologists with 2-D echocardiography and Doppler before the procedure. Success of closure and complications were recorded. Results: The age of patients varied from 05 - 12 months and 31 (56.4%) were females. Out of the 55 infants, 3 (5.4%) were not offered device closure after aortogram (two large tubular type ducts and one tiny duct, considered unsuitable for device closure); while in 50 (96.1%) patients out of remaining 52, the duct was successfully closed with transcatheter PDA device or coil. In one infant, device deployment resulted in acquired coarctation, necessitating device retrieval by Snare followed by surgical duct interruption and another patient had non-fatal cardiac arrest during device deployment leading to abandonment of procedure and subsequent successful surgical interruption. Local vascular complications occurred in 12 (21.8%) of cases and all were satisfactorily treated. Conclusion: Transcatheter device closure of PDA in infants was an effective procedure in the majority of cases; however, here were considerable number of local access site vascular complications. (author)

3718-F Alkali Metal Treatment and Storage Facility Closure Plan

International Nuclear Information System (INIS)

1991-12-01

Since 1987, Westinghouse Hanford Company has been a major contractor to the U.S. Department of Energy-Richland Operations Office and has served as co-operator of the 3718-F Alkali Metal Treatment and Storage Facility, the waste management unit addressed in this closure plan. The closure plan consists of a Part A Dangerous waste Permit Application and a RCRA Closure Plan. An explanation of the Part A Revision (Revision 1) submitted with this document is provided at the beginning of the Part A section. The closure plan consists of 9 chapters and 5 appendices. The chapters cover: introduction; facility description; process information; waste characteristics; groundwater; closure strategy and performance standards; closure activities; postclosure; and references

3718-F Alkali Metal Treatment and Storage Facility Closure Plan

Energy Technology Data Exchange (ETDEWEB)

None

1991-12-01

Since 1987, Westinghouse Hanford Company has been a major contractor to the U.S. Department of Energy-Richland Operations Office and has served as co-operator of the 3718-F Alkali Metal Treatment and Storage Facility, the waste management unit addressed in this closure plan. The closure plan consists of a Part A Dangerous waste Permit Application and a RCRA Closure Plan. An explanation of the Part A Revision (Revision 1) submitted with this document is provided at the beginning of the Part A section. The closure plan consists of 9 chapters and 5 appendices. The chapters cover: introduction; facility description; process information; waste characteristics; groundwater; closure strategy and performance standards; closure activities; postclosure; and references.

Implementing a flipped classroom approach in a university numerical methods mathematics course

Science.gov (United States)

Johnston, Barbara M.

2017-05-01

This paper describes and analyses the implementation of a 'flipped classroom' approach, in an undergraduate mathematics course on numerical methods. The approach replaced all the lecture contents by instructor-made videos and was implemented in the consecutive years 2014 and 2015. The sequential case study presented here begins with an examination of the attitudes of the 2014 cohort to the approach in general as well as analysing their use of the videos. Based on these responses, the instructor makes a number of changes (for example, the use of 'cloze' summary notes and the introduction of an extra, optional tutorial class) before repeating the 'flipped classroom' approach the following year. The attitudes to the approach and the video usage of the 2015 cohort are then compared with the 2014 cohort and further changes that could be implemented for the next cohort are suggested.

Patent foramen ovale closure using a bioabsorbable closure device: safety and efficacy at 6-month follow-up.

Science.gov (United States)

Van den Branden, Ben J; Post, Martijn C; Plokker, Herbert W; ten Berg, Jurriën M; Suttorp, Maarten J

2010-09-01

The aim of this study was to assess the mid-term safety and efficacy of percutaneous patent foramen ovale (PFO) closure using a bioabsorbable device (BioSTAR, NMT Medical, Boston, Massachusetts). Closure of PFO in patients with cryptogenic stroke has proven to be safe and effective using different types of permanent devices. All consecutive patients who underwent percutaneous PFO closure with the bioabsorbable closure device between November 2007 and January 2009 were included. Residual shunt was assessed using contrast transthoracic echocardiography. Sixty-two patients (55% women, mean age 47.7 ± 11.8 years) underwent PFO closure. The in-hospital complications were a surgical device retrieval in 2 patients (3.2%), device reposition in 1 (1.6%), and a minimal groin hematoma in 6 patients (9.7%). The short-term complications at 1-month follow-up (n = 60) were a transient ischemic attack in the presence of a residual shunt in 1 patient and new supraventricular tachycardia in 7 patients (11.3%). At 6-month follow-up (n = 60), 1 patient without residual shunt developed a transient ischemic attack and 1 developed atrial fibrillation. A mild or moderate residual shunt was noted in 51.7%, 33.9%, and 23.7% after 1-day, 1-month, and 6-month follow-up, respectively. A large shunt was present in 8.3%, 3.4%, and 0% after 1-day, 1-month, and 6-month follow-up. Closure of PFO using the bioabsorbable device is associated with a low complication rate and a low recurrence rate of embolic events. However, a relatively high percentage of mild or moderate residual shunting is still present at 6-month follow-up. Copyright © 2010 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Incorporating Sustainability into Site Closure - A Field Example

Science.gov (United States)

Austrins, L. M.; West, J.

2013-12-01

Long term management of former chemical production facilities can be a costly and time consuming element of site closure, however, implementation of creative measures to introduce sustainability and reduce the need for onsite presence can be successfully incorporated into the site closure process. A case study demonstrating this involves a facility located in Sarnia, Ontario, which was an active multi chemical production facility from the 1940s, until it was decommissioned and sold between 2005 and 2010. The facility consisted of 322 acres of production areas. Several elements which allowed for reduced onsite presence and lower management costs were incorporated into the site decommissioning plan, including; phased remediation planning, and selection of sustainable components as part of remediation, surface water management, and groundwater management. The sustainability and management modifications were successfully negotiated and approved by the local regulatory agency. Due to the size and complexity of the site, a holistic approach for the facility was needed and included the development of a comprehensive decision matrix. Each remediation alternative incorporated sustainable practices. Ex-situ remediation consisted of excavation of contaminated subsurface medium and consolidation at a 4.7 acre onsite soil treatment area designed specifically for the site closure process. In-situ remediation consisted of injection of amendment into the native soils using hydraulic fracture and injection. When the plant was an active operating facility, groundwater management required active pumping and groundwater treatment through a series of carbon treatment units. Active pumping has been replaced by passive hydraulic control through the use of tree plantations.

How does the closure of interorganizational relationships affect entrepreneurial orientation?

Directory of Open Access Journals (Sweden)

María José Ruiz-Ortega

2017-07-01

Full Text Available This study delves in the controversy about the nature and the sign of the effect of interorganizational relationships on entrepreneurial orientation. The paper analyses the effects of networks of interorganizational relationships at firm level. Specifically, we study the influence of closure of interorganizational relationships in entrepreneurial orientation and the mediating role of dynamic capabilities. The empirical analysis was developed on a sample of 292 Spanish agri-food firms. We detect a positive mediating effect of the closure of interorganizational relationships, mainly cooperative relationships, on entrepreneurial orientation through dynamic capabilities. It highlights the emergence of a suppression effect uncovering the dark side of closed interorganizational relationships in several dimensions of entrepreneurial orientation – proactiveness, autonomy and risk-taking –. This paper contributes to link three theoretical approaches – social capital, entrepreneurship and dynamic capabilities – to probe further into the implications of interorganizational relationships.

Pricing index-based catastrophe bonds: Part 1: Formulation and discretization issues using a numerical PDE approach

Science.gov (United States)

Unger, André J. A.

2010-02-01

This work is the first installment in a two-part series, and focuses on the development of a numerical PDE approach to price components of a Bermudan-style callable catastrophe (CAT) bond. The bond is based on two underlying stochastic variables; the PCS index which posts quarterly estimates of industry-wide hurricane losses as well as a single-factor CIR interest rate model for the three-month LIBOR. The aggregate PCS index is analogous to losses claimed under traditional reinsurance in that it is used to specify a reinsurance layer. The proposed CAT bond model contains a Bermudan-style call feature designed to allow the reinsurer to minimize their interest rate risk exposure on making substantial fixed coupon payments using capital from the reinsurance premium. Numerical PDE methods are the fundamental strategy for pricing early-exercise constraints, such as the Bermudan-style call feature, into contingent claim models. Therefore, the objective and unique contribution of this first installment in the two-part series is to develop a formulation and discretization strategy for the proposed CAT bond model utilizing a numerical PDE approach. Object-oriented code design is fundamental to the numerical methods used to aggregate the PCS index, and implement the call feature. Therefore, object-oriented design issues that relate specifically to the development of a numerical PDE approach for the component of the proposed CAT bond model that depends on the PCS index and LIBOR are described here. Formulation, numerical methods and code design issues that relate to aggregating the PCS index and introducing the call option are the subject of the companion paper.

A New Framework to Compare Mass-Flux Schemes Within the AROME Numerical Weather Prediction Model

Science.gov (United States)

Riette, Sébastien; Lac, Christine

2016-08-01

In the Application of Research to Operations at Mesoscale (AROME) numerical weather forecast model used in operations at Météo-France, five mass-flux schemes are available to parametrize shallow convection at kilometre resolution. All but one are based on the eddy-diffusivity-mass-flux approach, and differ in entrainment/detrainment, the updraft vertical velocity equation and the closure assumption. The fifth is based on a more classical mass-flux approach. Screen-level scores obtained with these schemes show few discrepancies and are not sufficient to highlight behaviour differences. Here, we describe and use a new experimental framework, able to compare and discriminate among different schemes. For a year, daily forecast experiments were conducted over small domains centred on the five French metropolitan radio-sounding locations. Cloud base, planetary boundary-layer height and normalized vertical profiles of specific humidity, potential temperature, wind speed and cloud condensate were compared with observations, and with each other. The framework allowed the behaviour of the different schemes in and above the boundary layer to be characterized. In particular, the impact of the entrainment/detrainment formulation, closure assumption and cloud scheme were clearly visible. Differences mainly concerned the transport intensity thus allowing schemes to be separated into two groups, with stronger or weaker updrafts. In the AROME model (with all interactions and the possible existence of compensating errors), evaluation diagnostics gave the advantage to the first group.

Objects as closures: Abstract semantics of object oriented languages

Science.gov (United States)

Reddy, Uday S.

1989-01-01

We discuss denotational semantics of object-oriented languages, using the concept of closure widely used in (semi) functional programming to encapsulate side effects. It is shown that this denotational framework is adequate to explain classes, instantiation, and inheritance in the style of Simula as well as SMALLTALK-80. This framework is then compared with that of Kamin, in his recent denotational definition of SMALLTALK-80, and the implications of the differences between the two approaches are discussed.

Objects as closures - Abstract semantics of object oriented languages

Science.gov (United States)

Reddy, Uday S.

1988-01-01

The denotational semantics of object-oriented languages is discussed using the concept of closure widely used in (semi) functional programming to encapsulate side effects. It is shown that this denotational framework is adequate to explain classes, instantiation, and inheritance in the style of Simula as well as SMALLTALK-80. This framework is then compared with that of Kamin (1988), in his recent denotational definition of SMALLTALK-80, and the implications of the differences between the two approaches are discussed.

Numerical Optimization Design of Dynamic Quantizer via Matrix Uncertainty Approach

Directory of Open Access Journals (Sweden)

Kenji Sawada

2013-01-01

Full Text Available In networked control systems, continuous-valued signals are compressed to discrete-valued signals via quantizers and then transmitted/received through communication channels. Such quantization often degrades the control performance; a quantizer must be designed that minimizes the output difference between before and after the quantizer is inserted. In terms of the broadbandization and the robustness of the networked control systems, we consider the continuous-time quantizer design problem. In particular, this paper describes a numerical optimization method for a continuous-time dynamic quantizer considering the switching speed. Using a matrix uncertainty approach of sampled-data control, we clarify that both the temporal and spatial resolution constraints can be considered in analysis and synthesis, simultaneously. Finally, for the slow switching, we compare the proposed and the existing methods through numerical examples. From the examples, a new insight is presented for the two-step design of the existing continuous-time optimal quantizer.

Emergent properties during dorsal closure in Drosophila morphogenesis

International Nuclear Information System (INIS)

Peralta, X G; Toyama, Y; Edwards, G S; Kiehart, D P

2008-01-01

Dorsal closure is an essential stage of Drosophila development that is a model system for research in morphogenesis and biological physics. Dorsal closure involves an orchestrated interplay between gene expression and cell activities that produce shape changes, exert forces and mediate tissue dynamics. We investigate the dynamics of dorsal closure based on confocal microscopic measurements of cell shortening in living embryos. During the mid-stages of dorsal closure we find that there are fluctuations in the width of the leading edge cells but the time-averaged analysis of measurements indicate that there is essentially no net shortening of cells in the bulk of the leading edge, that contraction predominantly occurs at the canthi as part of the process for zipping together the two leading edges of epidermis and that the rate constant for zipping correlates with the rate of movement of the leading edges. We characterize emergent properties that regulate dorsal closure, i.e., a velocity governor and the coordination and synchronization of tissue dynamics

DEVELOPING AND QUANTIFYING PARAMETERS FOR CLOSURE WELDING OVERPACKS CONTAINING RESEARCH REACTOR SPENT NUCLEAR FUEL AT HANFORD

International Nuclear Information System (INIS)

CANNELL GR

2007-01-01

Fluor engineers developed a Gas Tungsten Arc Welding (GTAW) technique and parameters, demonstrated requisite weld quality and successfully closure-welded packaged spent nuclear fuel (SNF) overpacks at the Hanford Site. This paper reviews weld development and qualification activities associated with the overpack closure-welding and provides a summary of the production campaign. The primary requirement of the closure weld is to provide leaktight confinement of the packaged material against release to the environment during interim storage (40-year design term). Required weld quality, in this case, was established through up-front development and qualification, and then verification of parameter compliance during production welding. This approach was implemented to allow for a simpler overpack design and more efficient production operations than possible with approaches using routine post-weld testing and nondestructive examination (NDE). . A series of welding trials were conducted to establish the desired welding technique and parameters. Qualification of the process included statistical evaluation and American Society of Mechanical Engineers (ASME) Section IX testing. In addition, pull testing with a weighted mockup, and thermal calculation/physical testing to identify the maximum temperature the packaged contents would be subject to during welding, was performed. Thirteen overpacks were successfully packaged and placed into interim storage. The closure-welding development activities (including pull testing and thermal analysis) provided the needed confidence that the packaged SNF overpacks could be safely handled and placed into interim storage, and remain leaktight for the duration of the storage term

A new numerical approach for uniquely solvable exterior Riemann-Hilbert problem on region with corners

Science.gov (United States)

Zamzamir, Zamzana; Murid, Ali H. M.; Ismail, Munira

2014-06-01

Numerical solution for uniquely solvable exterior Riemann-Hilbert problem on region with corners at offcorner points has been explored by discretizing the related integral equation using Picard iteration method without any modifications to the left-hand side (LHS) and right-hand side (RHS) of the integral equation. Numerical errors for all iterations are converge to the required solution. However, for certain problems, it gives lower accuracy. Hence, this paper presents a new numerical approach for the problem by treating the generalized Neumann kernel at LHS and the function at RHS of the integral equation. Due to the existence of the corner points, Gaussian quadrature is employed which avoids the corner points during numerical integration. Numerical example on a test region is presented to demonstrate the effectiveness of this formulation.

Analytic-Numerical Approach to Solving Singularly Perturbed Parabolic Equations with the Use of Dynamic Adapted Meshes

Directory of Open Access Journals (Sweden)

D. V. Lukyanenko

2016-01-01

Full Text Available The main objective of the paper is to present a new analytic-numerical approach to singularly perturbed reaction-diffusion-advection models with solutions containing moving interior layers (fronts. We describe some methods to generate the dynamic adapted meshes for an efficient numerical solution of such problems. It is based on a priori information about the moving front properties provided by the asymptotic analysis. In particular, for the mesh construction we take into account a priori asymptotic evaluation of the location and speed of the moving front, its width and structure. Our algorithms significantly reduce the CPU time and enhance the stability of the numerical process compared with classical approaches.The article is published in the authors’ wording.

Changes in ocular biometry and anterior chamber parameters after pharmacologic mydriasis and peripheral iridotomy in primary angle closure suspects

Directory of Open Access Journals (Sweden)

Mohammad Reza Razeghinejad

2016-07-01

Conclusions: This study showed no change in the ocular biometric and anterior chamber parameters including iridocorneal angle after PI and/or pharmacologic mydriasis except for increments in anterior chamber volume. This factor has the potential to be used as a numerical proxy for iris position in evaluating and monitoring patients with primary angle closure suspects after PI.

Topological transitions at finite temperatures: A real-time numerical approach

International Nuclear Information System (INIS)

Grigoriev, D.Yu.; Rubakov, V.A.; Shaposhnikov, M.E.

1989-01-01

We study topological transitions at finite temperatures within the (1+1)-dimensional abelian Higgs model by a numerical simulation in real time. Basic ideas of the real-time approach are presented and some peculiarities of the Metropolis technique are discussed. It is argued that the processes leading to topological transitions are of classical origin; the transitions can be observed by solving the classical field equations in real time. We show that the topological transitions actually pass via the sphaleron configuration. The transition rate as a function of temperature is found to be in good agreement with the analytical predictions. No extra suppression of the rate is observed. The conditions of applicability of our approach are discussed. The temperature interval where the low-temperature broken phase persists is estimated. (orig.)

Numerical relativity

International Nuclear Information System (INIS)

Piran, T.

1982-01-01

There are many recent developments in numerical relativity, but there remain important unsolved theoretical and practical problems. The author reviews existing numerical approaches to solution of the exact Einstein equations. A framework for classification and comparison of different numerical schemes is presented. Recent numerical codes are compared using this framework. The discussion focuses on new developments and on currently open questions, excluding a review of numerical techniques. (Auth.)

A neural approach for the numerical modeling of two-dimensional magnetic hysteresis

International Nuclear Information System (INIS)

Cardelli, E.; Faba, A.; Laudani, A.; Riganti Fulginei, F.; Salvini, A.

2015-01-01

This paper deals with a neural network approach to model magnetic hysteresis at macro-magnetic scale. Such approach to the problem seems promising in order to couple the numerical treatment of magnetic hysteresis to FEM numerical solvers of the Maxwell's equations in time domain, as in case of the non-linear dynamic analysis of electrical machines, and other similar devices, making possible a full computer simulation in a reasonable time. The neural system proposed consists of four inputs representing the magnetic field and the magnetic inductions components at each time step and it is trained by 2-d measurements performed on the magnetic material to be modeled. The magnetic induction B is assumed as entry point and the output of the neural system returns the predicted value of the field H at the same time step. A suitable partitioning of the neural system, described in the paper, makes the computing process rather fast. Validations with experimental tests and simulations for non-symmetric and minor loops are presented

Numerical and experimental approaches to simulate soil clogging in porous media

Science.gov (United States)

Kanarska, Yuliya; LLNL Team

2012-11-01

Failure of a dam by erosion ranks among the most serious accidents in civil engineering. The best way to prevent internal erosion is using adequate granular filters in the transition areas where important hydraulic gradients can appear. In case of cracking and erosion, if the filter is capable of retaining the eroded particles, the crack will seal and the dam safety will be ensured. A finite element numerical solution of the Navier-Stokes equations for fluid flow together with Lagrange multiplier technique for solid particles was applied to the simulation of soil filtration. The numerical approach was validated through comparison of numerical simulations with the experimental results of base soil particle clogging in the filter layers performed at ERDC. The numerical simulation correctly predicted flow and pressure decay due to particle clogging. The base soil particle distribution was almost identical to those measured in the laboratory experiment. To get more precise understanding of the soil transport in granular filters we investigated sensitivity of particle clogging mechanisms to various aspects such as particle size ration, the amplitude of hydraulic gradient, particle concentration and contact properties. By averaging the results derived from the grain-scale simulations, we investigated how those factors affect the semi-empirical multiphase model parameters in the large-scale simulation tool. The Department of Homeland Security Science and Technology Directorate provided funding for this research.

Economic evaluation of closure cap barrier materials study

Energy Technology Data Exchange (ETDEWEB)

Serrato, M.G.; Bhutani, J.S.; Mead, S.M.

1993-09-01

Volume II of the Economic Evaluation of the Closure Cap Barrier Materials, Revision I contains detailed cost estimates for closure cap barrier materials. The cost estimates incorporate the life cycle costs for a generic hazardous waste seepage basin closure cap under the RCRA Post Closure Period of thirty years. The economic evaluation assessed six barrier material categories. Each of these categories consists of several composite cover system configurations, which were used to develop individual cost estimates. The information contained in this report is not intended to be used as a cost estimating manual. This information provides the decision makers with the ability to screen barrier materials, cover system configurations, and identify cost-effective materials for further consideration.

Economic evaluation of closure cap barrier materials study

International Nuclear Information System (INIS)

Serrato, M.G.; Bhutani, J.S.; Mead, S.M.

1993-09-01

Volume II of the Economic Evaluation of the Closure Cap Barrier Materials, Revision I contains detailed cost estimates for closure cap barrier materials. The cost estimates incorporate the life cycle costs for a generic hazardous waste seepage basin closure cap under the RCRA Post Closure Period of thirty years. The economic evaluation assessed six barrier material categories. Each of these categories consists of several composite cover system configurations, which were used to develop individual cost estimates. The information contained in this report is not intended to be used as a cost estimating manual. This information provides the decision makers with the ability to screen barrier materials, cover system configurations, and identify cost-effective materials for further consideration

Key financial ratios can foretell hospital closures.

Science.gov (United States)

Lynn, M L; Wertheim, P

1993-11-01

An analysis of various financial ratios sampled from open and closed hospitals shows that certain leverage, liquidity, capital efficiency, and resource availability ratios can predict hospital closure up to two years in advance of the closure with an accuracy of nearly 75 percent.

Hospital closure: Phoenix, Hydra or Titanic?

Science.gov (United States)

Dunne, T; Davis, S

1996-01-01

Very little has been published about the effects of hospital closure in terms of the service, financial or management issues of the process. Attempts through a case-study format to redress the balance and as such represents the reflections of practitioners who have recently undergone the experience of hospital closure and the often neglected issues arising both during and after the process.

Potential socio-economic consequences of mine closure

Directory of Open Access Journals (Sweden)

Marietjie Ackermann

2018-01-01

Full Text Available Background: Mine closures generally reveal negligence on the part of mining houses, not only in terms of the environment, but also the surrounding mining communities. Aim: This article reflects on the findings of research into the socio-economic consequences of mine closure. The research specifically explored how mineworkers’ dependency on their employment at a mine affects their ability to sustain their livelihood. Setting: The research was conducted at the Orkney Mine and the Grootvlei Mine (Springs. Methods: The research was conducted within a naturalistic domain, guided by a relativist orientation, a constructivist ontology and an interpretivist epistemology. Data were collected by means of document analysis, semi-structured interviews, focus group discussion and unstructured observation. Results: From the research findings, it is evident that mine closures, in general, have a devastating effect on the surrounding mining communities as well as on the employees. Mine closures in the case studies gradually depleted the mining communities’ livelihood assets and resulted in the collapse of their coping strategies and livelihood outcomes. It generally affected the communities’ nutrition, health, education, food security, water, shelter, levels of community participation and personal safety. Conclusion: If not managed efficiently and effectively, mine closures may pose significant challenges to the mining industry, government, the environment, national and local economic prosperity and communities in the peripheral areas of mines. This truly amplifies that mine closure, whether temporary or permanent, is an issue that needs to be addressed with responsibility towards all stakeholders, including the mining community and the labour force.

Top closure for control rod drive for nuclear reactor

International Nuclear Information System (INIS)

Raas, J.H.; Schwartz, J.I.

1978-01-01

A removable top closure and venting assembly for the tubular housing of a control rod drive includes a mounting ring threadably inserted in the upper end of the housing, a fluid-sealing closure member beneath the mounting ring and which is mounted in and coupled to the mounting ring by means of a ball and socket joint, a gas vent defined by interconnecting passages extending through the closure and through the ball and socket joint, and a vent valve accessible from the top of the closure assembly. 3 claims, 2 figures

Transcatheter closure of ventricular septal defect with Occlutech Duct Occluder.

Science.gov (United States)

Atik-Ugan, Sezen; Saltik, Irfan Levent

2018-04-01

Patent ductus arteriosus occluders are used for transcatheter closure of ventricular septal defects, as well as for closure of patent ductus arteriosus. The Occlutech Duct Occluder is a newly introduced device for transcatheter closure of patent ductus arteriosus. Here, we present a case in which the Occlutech Duct Occluder was successfully used on a patient for the closure of a perimembraneous ventricular septal defect.

Seven-year follow-up of percutaneous closure of patent foramen ovale.

Science.gov (United States)

Mirzada, Naqibullah; Ladenvall, Per; Hansson, Per-Olof; Johansson, Magnus Carl; Furenäs, Eva; Eriksson, Peter; Dellborg, Mikael

2013-12-01

Observational studies favor percutaneous closure of patent foramen ovale (PFO) over medical treatment to reduce recurrent stroke while randomized trials fail to demonstrate significant superiority of percutaneous PFO closure. Few long-term studies are available post PFO closure. This study reports long-term clinical outcomes after percutaneous PFO closure. Between 1997 and 2006, 86 consecutive eligible patients with cerebrovascular events, presumably related to PFO, underwent percutaneous PFO closure. All 86 patients were invited to a long-term follow-up, which was carried out during 2011 and 2012. Percutaneous PFO closure was successfully performed in 85 of 86 patients. The follow-up rate was 100%. No cardiovascular or cerebrovascular deaths occurred. Two patients (both women) died from lung cancer during follow-up. Follow-up visits were conducted for 64 patients and the remaining 20 patients were followed up by phone. The mean follow-up time was 7.3 years (5 to 12.4 years). Mean age at PFO closure was 49 years. One patient had a minor stroke one month after PFO closure and a transient ischemic attack (TIA) two years afterwards. One other patient suffered from a TIA six years after closure. No long-term device-related complications were observed. Percutaneous PFO closure was associated with very low risk of recurrent stroke and is suitable in most patients. We observed no mortality and no long-term device-related complications related to PFO closure, indicating that percutaneous PFO closure is a safe and efficient treatment even in the long term.

Permanent Closure of the TAN-664 Underground Storage Tank

Energy Technology Data Exchange (ETDEWEB)

Bradley K. Griffith

2011-12-01

This closure package documents the site assessment and permanent closure of the TAN-664 gasoline underground storage tank in accordance with the regulatory requirements established in 40 CFR 280.71, 'Technical Standards and Corrective Action Requirements for Owners and Operators of Underground Storage Tanks: Out-of-Service UST Systems and Closure.'

Single-shell tank closure work plan. Revision A

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-06-01

In January 1994, the Hanford Federal Facility Agreement and Conset Order (Tri-Party Agreement) was amended to reflect a revised strategy for remediation of radioactive waste in underground storage tanks. These amendments include milestones for closure of the single-shell tank (SST) operable units, to be initiated by March 2012 and completed by September 2024. This SST-CWP has been prepared to address the principal topical areas identified in Tri-Party Agreement Milestone M-45-06 (i.e., regulatory pathway, operable unit characterization, waste retrieval, technology development, and a strategy for achieving closure). Chapter 2.0 of this SST-CWP provides a brief description of the environmental setting, SST System, the origin and characteristics of SST waste, and ancillary equipment that will be remediated as part of SST operable unit closure. Appendix 2A provides a description of the hydrogeology of the Hanford Site, including information on the unsaturated sediments (vadose zone) beneath the 200 Areas Plateau. Chapter 3.0 provides a discussion of the laws and regulations applicable to closure of the SST farm operable units. Chapter 4.0 provides a summary description of the ongoing characterization activities that best align with the proposed regulatory pathway for closure. Chapter 5.0 describes aspects of the SST waste retrieval program, including retrieval strategy, technology, and sequence, potential tank leakage during retrieval, and considerations of deployment of subsurface barriers. Chapter 6.0 outlines a proposed strategy for closure. Chapter 7.0 provides a summary of the programs underway or planned to develop technologies to support closure. Ca. 325 refs.

Single-shell tank closure work plan. Revision A

International Nuclear Information System (INIS)

1995-06-01

In January 1994, the Hanford Federal Facility Agreement and Conset Order (Tri-Party Agreement) was amended to reflect a revised strategy for remediation of radioactive waste in underground storage tanks. These amendments include milestones for closure of the single-shell tank (SST) operable units, to be initiated by March 2012 and completed by September 2024. This SST-CWP has been prepared to address the principal topical areas identified in Tri-Party Agreement Milestone M-45-06 (i.e., regulatory pathway, operable unit characterization, waste retrieval, technology development, and a strategy for achieving closure). Chapter 2.0 of this SST-CWP provides a brief description of the environmental setting, SST System, the origin and characteristics of SST waste, and ancillary equipment that will be remediated as part of SST operable unit closure. Appendix 2A provides a description of the hydrogeology of the Hanford Site, including information on the unsaturated sediments (vadose zone) beneath the 200 Areas Plateau. Chapter 3.0 provides a discussion of the laws and regulations applicable to closure of the SST farm operable units. Chapter 4.0 provides a summary description of the ongoing characterization activities that best align with the proposed regulatory pathway for closure. Chapter 5.0 describes aspects of the SST waste retrieval program, including retrieval strategy, technology, and sequence, potential tank leakage during retrieval, and considerations of deployment of subsurface barriers. Chapter 6.0 outlines a proposed strategy for closure. Chapter 7.0 provides a summary of the programs underway or planned to develop technologies to support closure. Ca. 325 refs

Social and macro economic impact of closure

International Nuclear Information System (INIS)

Medeliene, D.

1999-01-01

The social consequences of closure of Ignalina NPP will largely depend on the actions the Government takes. If it puts in place the conditions which enable the International Financial Institutions to assist Lithuania, both in providing loans and grants for decommissioning and (in the case of the EU) providing Structural Adjustment Funds for the regional economic development of the Visaginas area, then solutions to the problems of closure can be found. But if the Government delays putting into place the necessary conditions, then Lithuania will be left to solve the problems of - inter alia necessary - closure of Ignalina NPP on its own. (author)

Angle closure glaucoma in congenital ectropion uvea

Directory of Open Access Journals (Sweden)

Grace M. Wang

2018-06-01

Full Text Available Purpose: Congenital ectropion uvea is a rare anomaly, which is associated with open, but dysplastic iridocorneal angles that cause childhood glaucoma. Herein, we present 3 cases of angle-closure glaucoma in children with congenital ectropion uvea. Observations: Three children were initially diagnosed with unilateral glaucoma secondary to congenital ectropion uvea at 7, 8 and 13 years of age. The three cases showed 360° of ectropion uvea and iris stromal atrophy in the affected eye. In one case, we have photographic documentation of progression to complete angle closure, which necessitated placement of a glaucoma drainage device 3 years after combined trabeculotomy and trabeculectomy. The 2 other cases, which presented as complete angle closure, also underwent glaucoma drainage device implantation. All three cases had early glaucoma drainage device encapsulation (within 4 months and required additional surgery (cycloablation or trabeculectomy. Conclusions and importance: Congenital ectropion uvea can be associated with angle-closure glaucoma, and placement of glaucoma drainage devices in all 3 of our cases showed early failure due to plate encapsulation. Glaucoma in congenital ectropion uvea requires attention to angle configuration and often requires multiple surgeries to obtain intraocular pressure control. Keywords: Congenital ectropion uvea, Juvenile glaucoma, Angle-closure glaucoma, Glaucoma drainage device

Undetected angle closure in patients with a diagnosis of open-angle glaucoma.

Science.gov (United States)

Varma, Devesh K; Simpson, Sarah M; Rai, Amandeep S; Ahmed, Iqbal Ike K

2017-08-01

The aim of this study was to identify the proportion of patients referred to a tertiary glaucoma centre with a diagnosis of open-angle glaucoma (OAG) who were found to have angle closure glaucoma. Retrospective chart review. Consecutive new patients referred for glaucoma management to a tertiary centre between July 2010 and December 2011 were reviewed. Patients whose referrals for glaucoma assessment specified angle status as "open" were included. The data collected included glaucoma specialist's angle assessment, diagnosis, and glaucoma severity. The status of those with 180 degrees or more Shaffer angle grading of 0 was classified as "closed." From 1234 glaucoma referrals, 179 cases were specified to have a diagnosis of OAG or when angles were known to be open. Of these, 16 (8.9%) were found on examination by the glaucoma specialist to have angle closure. Pseudoexfoliation was present in 4 of 16 patients (25%) in the missed angle-closure glaucoma (ACG) group and 22 of 108 patients (13.5%) in the remaining OAG group. There was no difference found in demographic or ocular biometric parameters between those with confirmed OAG versus those with missed ACG. Almost 1 in 11 patients referred by ophthalmologists to a tertiary glaucoma centre with a diagnosis of OAG were in fact found to have angle closure. Given the different treatment approaches for ACG versus OAG, this study suggests a need to strengthen angle evaluations. Copyright © 2017 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

Project management approach for the Waste Area Grouping 6 Closure/Remediation Project at Oak Ridge National Laboratory, Oak Ridge, Tennessee

International Nuclear Information System (INIS)

1992-07-01

This document has been developed as a preliminary definition of the Waste Area Grouping (WAG) 6 Closure Project Management Approach. The purpose of this document is to identify the roles and responsibilities of the various project team members and to identify the project scope, schedule and budget. This document is intended to be a living document. As information develops, this document will be revised to create a WAG 6 Project Management Plan (PMP). The PMP will provide additional focus to the information contained in this document. The information required will be available as the selected alternative for remediation of WAG 6 is approved and Remedial Action Plans are conceptualized. This document has been reviewed against, and is intended to be consistent with, the Environmental Restoration Program Management Plan

Role of plasticity-induced crack closure in fatigue crack growth

Directory of Open Access Journals (Sweden)

Jesús Toribio

2013-07-01

Full Text Available The premature contact of crack surfaces attributable to the near-tip plastic deformations under cyclic loading, which is commonly referred to as plasticity induced crack closure (PICC, has long been focused as supposedly controlling factor of fatigue crack growth (FCG. Nevertheless, when the plane-strain near-tip constraint is approached, PICC lacks of straightforward evidence, so that its significance in FCG, and even the very existence, remain debatable. To add insights into this matter, large-deformation elastoplastic simulations of plane-strain crack under constant amplitude load cycling at different load ranges and ratios, as well as with an overload, have been performed. Modeling visualizes the Laird-Smith conceptual mechanism of FCG by plastic blunting and re-sharpening. Simulation reproduces the experimental trends of FCG concerning the roles of stress intensity factor range and overload, but PICC has never been detected. Near-tip deformation patterns discard the filling-in a crack with material stretched out of the crack plane in the wake behind the tip as supposed PICC origin. Despite the absence of closure, load-deformation curves appear bent, which raises doubts about the trustworthiness of closure assessment from the compliance variation. This demonstrates ambiguities of PICC as a supposedly intrinsic factor of FCG and, by implication, favors the stresses and strains in front of the crack tip as genuine fatigue drivers.

[Surgical closure of patent ductus arteriosus in premature neonates: Does the surgical technique affect the outcome?

Science.gov (United States)

Avila-Alvarez, Alejandro; Serantes Lourido, Marta; Barriga Bujan, Rebeca; Blanco Rodriguez, Carolina; Portela-Torron, Francisco; Bautista-Hernandez, Victor

2017-05-01

Surgical closure of patent ductus arteriosus in premature neonates is an aggressive technique and is not free of complications. A study was designed with the aim of describing our experience with a less invasive technique, the extra-pleural approach via a posterior minithoracotomy, and to compare the results with the classic transpleural approach. A retrospective cohort study was conducted on premature neonates on whom surgical closure of the ductus was performed during a ten-year period (March 2005 to March 2015). A comparison was made of the acute complications, the outcomes on discharge, and follow-up, between the extra-pleural approach and the classic transpleural approach. The study included 48 patients, 30 in the classical approach and 18 in the extra-pleural group. The demographic and pre-operative characteristics were similar in both groups. No differences were found between the 2 groups in the incidence of acute post-operative complications (56.6 vs. 44.4%), on the dependence on oxygen at 36 weeks (33.3 vs. 55.5%), or in hospital mortality (10 vs. 16.6%). As regards the short-term progress, the extra-pleural group required fewer days until the withdrawal of supplementary oxygen (36.3 vs. 28.9) and until hospital discharge (67.5 vs. 53.2), although only the time until extubation achieved a statistically significant difference (11.5 vs. 2.7, P=.03). The extra-plural approach by posterior minithoracotomy for the surgical closure of ductus in the premature infant is viable and could bring some clinical benefits in the short-term. Copyright © 2015 Asociación Española de Pediatría. Publicado por Elsevier España, S.L.U. All rights reserved.

A comparison of two approaches to managing acute primary angle closure in Asian eyes

Directory of Open Access Journals (Sweden)

Ho H

2013-06-01

Full Text Available Henrietta Ho,1 Paul T Chew,2 Chelvin Sng,1,2 Huiqi Huang,1 Tin Aung,1,2 Shamira A Perera1,21Singapore Eye Research Institute, Singapore National Eye Centre, Singapore; 2Yong Loo Lin School of Medicine, National University of Singapore and National University Health System, SingaporePurpose: To review the management regimes of acute primary angle closure (APAC in two hospitals in Singapore, and to identify the incidence of and risk factors for progression to glaucomatous optic neuropathy.Methods: We conducted a retrospective review of 40 patients from National University Hospital (NUH and 52 patients from Singapore National Eye Centre (SNEC who were diagnosed with APAC. Patients were treated with similar protocols of intensive medical therapy until laser peripheral iridotomy could be performed. In the event of failed medical treatment, patients at NUH only underwent laser iridoplasty. The 1-year outcomes were reviewed.Results: The demographic features of patients and presenting intraocular pressures (IOP were similar in both centers. More patients from NUH presented within 3 days of symptom onset, compared to those from SNEC (90.0% versus 71.2%, respectively (P = 0.037. The mean ± standard deviation time to break the attack was 18.2 ± 32.9 hours at SNEC and 9.80 ± 10.6 hours at NUH (P = 0.11. The mean follow up duration was 18.8 ± 14.0 months. Nineteen patients (36.5% from SNEC and six patients (22.5% from NUH developed raised IOP (P = 0.032 within 1-year of the attack. Of these, glaucomatous optic neuropathy developed in thirteen patients (68.4% from SNEC and all six patients (100% from NUH. At final review, the mean IOP of the APAC eye was 14.8 ± 4.3 mmHg from SNEC and 13.4 ± 3.0 mmHg from NUH. There was no significant difference in final visual acuity or IOP between both groups.Conclusion: Treatment strategies in both centers were effective in aborting an APAC attack. The development of raised IOP appears to be associated with a longer

Numerical schemes for the hybrid modeling approach of gas-particle turbulent flows

International Nuclear Information System (INIS)

Dorogan, K.

2012-01-01

Hybrid Moments/PDF methods have shown to be well suitable for the description of poly-dispersed turbulent two-phase flows in non-equilibrium which are encountered in some industrial situations involving chemical reactions, combustion or sprays. They allow to obtain a fine enough physical description of the poly-dispersity, non-linear source terms and convection phenomena. However, their approximations are noised with the statistical error, which in several situations may be a source of a bias. An alternative hybrid Moments-Moments/PDF approach examined in this work consists in coupling the Moments and the PDF descriptions, within the description of the dispersed phase itself. This hybrid method could reduce the statistical error and remove the bias. However, such a coupling is not straightforward in practice and requires the development of accurate and stable numerical schemes. The approaches introduced in this work rely on the combined use of the up-winding and relaxation-type techniques. They allow to obtain stable unsteady approximations for a system of partial differential equations containing non-smooth external data which are provided by the PDF part of the model. A comparison of the results obtained using the present method with those of the 'classical' hybrid approach is presented in terms of the numerical errors for a case of a co-current gas-particle wall jet. (author)

Comparing over-the-scope clip versus endoloop and clips (KING closure) for access site closure: a randomized experimental study

Czech Academy of Sciences Publication Activity Database

Martínek, J.; Ryska, O.; Tučková, I.; Filípková, T.; Doležel, R.; Juhás, Štefan; Motlík, Jan; Zavoral, M.; Ryska, M.

2013-01-01

Roč. 27, č. 4 (2013), s. 1203-1210 ISSN 0930-2794 R&D Projects: GA MZd NS9994 Institutional research plan: CEZ:AV0Z50450515 Keywords : NOTES * gastrotomy closure * rectotomy closure Subject RIV: FJ - Surgery incl. Transplants Impact factor: 3.313, year: 2013

An efficient approach for computing the geometrical optics field reflected from a numerically specified surface

Science.gov (United States)

Mittra, R.; Rushdi, A.

1979-01-01

An approach for computing the geometrical optic fields reflected from a numerically specified surface is presented. The approach includes the step of deriving a specular point and begins with computing the reflected rays off the surface at the points where their coordinates, as well as the partial derivatives (or equivalently, the direction of the normal), are numerically specified. Then, a cluster of three adjacent rays are chosen to define a 'mean ray' and the divergence factor associated with this mean ray. Finally, the ampilitude, phase, and vector direction of the reflected field at a given observation point are derived by associating this point with the nearest mean ray and determining its position relative to such a ray.

Hexone Storage and Treatment Facility closure plan

International Nuclear Information System (INIS)

1992-11-01

The HSTF is a storage and treatment unit subject to the requirements for the storage and treatment of dangerous waste. Closure is being conducted under interim status and will be completed pursuant to the requirements of Washington State Department of Ecology (Ecology) Dangerous Waste Regulations, Washington Administrative Code (WAC) 173-303-610 and WAC 173-303-640. Because dangerous waste does not include the source, special nuclear, and by-product material components of mixed waste, radionuclides are not within the scope of WAC 173-303 or of this closure plan. The information on radionuclides is provided only for general knowledge where appropriate. The known hazardous/dangerous waste remaining at the site before commencing other closure activities consists of the still vessels, a tarry sludge in the storage tanks, and residual contamination in equipment, piping, filters, etc. The treatment and removal of waste at the HSTF are closure activities as defined in the Resource Conservation and Recovery Act (RCRA) of 1976 and WAC 173-303

Cyanoacrylate for Intraoral Wound Closure: A Possibility?

Directory of Open Access Journals (Sweden)

Parimala Sagar

2015-01-01

Full Text Available Wound closure is a part of any surgical procedure and the objective of laceration repair or incision closure is to approximate the edges of a wound so that natural healing process may occur. Over the years new biomaterials have been discovered as an alternate to conventional suture materials. Cyanoacrylate bioadhesives are one among them. They carry the advantages of rapid application, patient comfort, resistance to infection, hemostatic properties, and no suture removal anxiety. Hence this study was undertaken to study the effect of long chain cyanoacrylate as an adhesive for intraoral wound closure and also to explore its hemostatic and antibacterial effects. Isoamyl-2-cyanoacrylate (AMCRYLATE was used as the adhesive in the study. In conclusion isoamyl cyanoacrylate can be used for intraoral wound closure, as an alternative to sutures for gluing the mucoperiosteum to bone, for example, after impaction removal, periapical surgeries, and cleft repair. Its hemostatic and antibacterial activity has to be further evaluated.

A Full Hydro- and Morphodynamic Description of Breaker Bar Development

DEFF Research Database (Denmark)

Jacobsen, Niels Gjøl

The present thesis considers a coupled modelling approach for hydro- and morphodynamics in the surf zone, which is based on a solution to the Reynolds Averaged Navier-Stokes (RANS) equations with a Volume of Fluid (VOF) closure for the surf tracking. The basis for the numerical approach is the su......The present thesis considers a coupled modelling approach for hydro- and morphodynamics in the surf zone, which is based on a solution to the Reynolds Averaged Navier-Stokes (RANS) equations with a Volume of Fluid (VOF) closure for the surf tracking. The basis for the numerical approach...

Design, production and initial state of the closure

International Nuclear Information System (INIS)

2010-12-01

The report is included in a set of Production reports, presenting how the KBS-3 repository is designed, produced and inspected. The production reports are included in the safety report for the KBS-3 repository and repository facility. The report provides input on the initial state of the closure and plugs in underground openings other than deposition tunnels for the assessment of the long-term safety, SR-Site. The initial state refers to the properties of the engineered barriers once they have been finally placed in the KBS-3 repository and will not be further handled within the repository facility. In addition, the report provides some input to the operational safety report, SR-Operation, on how the closure and plugs shall be handled and installed. The report presents the design premises and reference designs of the closure and plugs and verifies their conformity to the design premises. It also briefly deals with the production of the closure and plugs. Finally, the initial state of the closure and plugs and their conformity to the reference designs and design premises are presented

Design, production and initial state of the closure

Energy Technology Data Exchange (ETDEWEB)

2010-12-15

The report is included in a set of Production reports, presenting how the KBS-3 repository is designed, produced and inspected. The production reports are included in the safety report for the KBS-3 repository and repository facility. The report provides input on the initial state of the closure and plugs in underground openings other than deposition tunnels for the assessment of the long-term safety, SR-Site. The initial state refers to the properties of the engineered barriers once they have been finally placed in the KBS-3 repository and will not be further handled within the repository facility. In addition, the report provides some input to the operational safety report, SR-Operation, on how the closure and plugs shall be handled and installed. The report presents the design premises and reference designs of the closure and plugs and verifies their conformity to the design premises. It also briefly deals with the production of the closure and plugs. Finally, the initial state of the closure and plugs and their conformity to the reference designs and design premises are presented

Direct numerical simulation of free convection in a vertical channel: a tool for second moment closure modeling

International Nuclear Information System (INIS)

Maupu, V.; Laurence, D.; Boudjemadi, R.; Le Quere, P.

1996-03-01

Natural turbulent convection in a differentially heated infinite vertical slot is computed with a mixed finite differences/Fourier code. At a Rayleigh number of 10 5 , periodic perturbations from the laminar solution develop and transition to a fully turbulent flow occurs. From then on, a database of high order correlations is constituted and used for testing a second moment closure based on the LRR model and elliptic relaxation near wall effects. Counter gradient turbulent transport, found in the central part of the channel, requires an algebraic model for the triple correlations instead of the standard DH or HL, gradient diffusion models. (authors). 18 refs., 14 figs., 1 tab

Transcatheter Closure of Patent Foramen Ovale: Devices and Technique.

Science.gov (United States)

Price, Matthew J

2017-10-01

Transcatheter closure of a patent foramen ovale (PFO) reduces the risk of recurrent cryptogenic stroke compared with medical therapy. PFO closure is a prophylactic procedure, and will not provide the patient with symptomatic improvement, except in cases of hypoxemia due to right-to-left shunt or possibly migraine headaches. Therefore, appropriate patient selection is critical, and procedural safety is paramount. Herein, we review key characteristics of the devices currently available for transcatheter PFO closure within the United States, and highlight key technical aspects of the PFO closure procedure that will maximize procedural success. Copyright © 2017 Elsevier Inc. All rights reserved.

Digital signal processing of data from borehole creep closure

International Nuclear Information System (INIS)

Chakrabarti, S.; Patrick, W.C.; Duplancic, N.

1987-01-01

Digital signal processing, a technique commonly used in the fields of electrical engineering and communication technology, has been successfully used to analyze creep closure data obtained from a 0.91 m diameter by 5.13 deep borehole in bedded salt. By filtering the ''noise'' component of the closure data from a test borehole, important data trends were made more evident and average creep closure rates were able to be calculated. This process provided accurate estimates of closure rates that are used in the design of lined boreholes in which heat-generating transuranic nuclear wastes are emplaced at the Waste Isolation Pilot Plant

40 CFR 264.119 - Post-closure notices.

Science.gov (United States)

2010-07-01

...) STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE, AND DISPOSAL FACILITIES Closure... closure of each hazardous waste disposal unit, the owner or operator must submit to the local zoning... disposal unit of the facility. For hazardous wastes disposed of before January 12, 1981, the owner or...

A closure test for time-specific capture-recapture data

Science.gov (United States)

Stanley, T.R.; Burnham, K.P.

1999-01-01

The assumption of demographic closure in the analysis of capture-recapture data under closed-population models is of fundamental importance. Yet, little progress has been made in the development of omnibus tests of the closure assumption. We present a closure test for time-specific data that, in principle, tests the null hypothesis of closed-population model M(t) against the open-population Jolly-Seber model as a specific alternative. This test is chi-square, and can be decomposed into informative components that can be interpreted to determine the nature of closure violations. The test is most sensitive to permanent emigration and least sensitive to temporary emigration, and is of intermediate sensitivity to permanent or temporary immigration. This test is a versatile tool for testing the assumption of demographic closure in the analysis of capture-recapture data.

Reliability in maintenance and design of elastomer sealed closures

International Nuclear Information System (INIS)

Lake, W.H.

1978-01-01

The methods of reliability are considered for maintenance and design of elastomer sealed containment closures. Component reliability is used to establish a replacement schedule for system maintenance. Reliability data on elastomer seals is used to evaluate the common practice of annual replacement, and to calculate component reliability values for several typical shipment time periods. System reliability methods are used to examine the relative merits of typical closure designs. These include single component and redundant seal closure, with and without closure verification testing. The paper presents a general method of quantifying the merits of closure designs through the use of reliability analysis, which is a probabilistic technique. The reference list offers a general source of information in the field of reliability, and should offer the opportunity to extend the procedures discussed in this paper to other design safety applications

A randomised controlled trial of absorbable versus non-absorbable sutures for skin closure after open carpal tunnel release.

LENUS (Irish Health Repository)

Theopold, C

2012-05-01

We compared the aesthetic outcome of scars after closure of open carpal tunnel incisions with either absorbable 4-0 Vicryl Rapide or non-absorbable 4-0 Novafil. Patients were recruited in a randomized controlled trial and scars were scored at 6 weeks using a modified Patient and Observer Scar Assessment Scale. Scores demonstrated differences only for pain, vascularity and cross-hatching between both groups, though none of these were statistically significant. The dissolving and falling out of Vicryl Rapide was significantly more comfortable than removal of 4-0 Novafil sutures, assessed on a numerical analogue scale. There was no difference in infection rate between both study groups, supporting overall the use of Vicryl Rapide for the closure of palmar hand incisions, in light of the convenience and cost savings associated with absorbable sutures.

The effectiveness of eye-closure in repeated interviews

OpenAIRE

Vredeveldt, A.; Baddeley, A.D.; Hitch, G.J.

2014-01-01

Purpose Closing the eyes during recall can help witnesses remember more about a witnessed event. This study examined the effectiveness of eye-closure in a repeated recall paradigm with immediate free recall followed 1 week later by both free and cued recall. We examined whether eye-closure was more or less effective during the second free-recall attempt compared with the first, whether eye-closure during the first recall attempt had an impact on subsequent free- and cued-recall performance, a...

324 Building REC and HLV Tank Closure Plan

International Nuclear Information System (INIS)

Becker-Khaleel, B.; Schlick, K.

1995-12-01

This closure plan describes the activities necessary to close the 324 Radiochemical Engineering Cells (REC) and High-Level Vault (HLV) in accordance with the Washington State Dangerous Waste regulations. To provide a complete description of the activities required, the closure plan relies on information contained in the 324 Building B-Cell Safety Cleanout Project (BCCP) plans, the 324 Building REC HLV Interim Waste Management Plan (IWMP), the Project Management Plan for Nuclear Facilities Management 300 Area Compliance Program, and the 324 High Level Vault Interim Removal Action Project (project management plan [PMP]). The IWMP addresses the management of mixed waste in accordance with state and federal hazardous waste regulations. It provides a strategy for managing high-activity mixed waste in compliance with Resource Conservation and Recovery Act (RCRA) requirements or provides for an alternative management approach for the waste. The BCCP outlines the past, present, and future activities necessary for removing from B-Cell the solid waste, including mixed waste generated as a result of historical research and development (R ampersand D) activities conducted in the cell. The BCCP also includes all records and project files associated with the B-Cell cleanout. This information is referenced throughout the closure plan. The PMP sets forth the plans, organization, and systems that Pacific Northwest National Laboratory (PNNL) will use to direct and control the 324 High-Level Vault Interim Removal Action Project. This project will develop and implement a treatment strategy that will remove and stabilize the inventory of liquid waste from the 324 HLV tanks. The PMP also provides for flushing and sampling the flush solution

Closure of the squared Zakharov--Shabat eigenstates

International Nuclear Information System (INIS)

Kaup, D.J.

1976-01-01

By solution of the inverse scattering problem for a third-order (degenerate) eigenvalue problem, the closure of the squared eigenfunctions of the Zakharov--Shabat equations is found. The question of the completeness of squared eigenstates occurs in many aspects of ''inverse scattering transforms'' (solving nonlinear evolution equations exactly by inverse scattering techniques), as well as in various aspects of the inverse scattering problem. The method used here is quite suggestive as to how one might find the closure of the squared eigenfunctions of other eigenvalue equations, and the strong analogy between these results and the problem of finding the closure of the eigenvectors of a nonself-adjoint matrix is pointed out

Stomal Closure: Strategies to Prevent Incisional Hernia

Science.gov (United States)

Harries, Rhiannon L.; Torkington, Jared

2018-01-01

Incisional hernias following ostomy reversal occur frequently. Incisional hernias at the site of a previous stoma closure can cause significant morbidity, impaired quality of life, lead to life-threatening hernia incarceration or strangulation and result in a significant financial burden on health care systems Despite this, the evidence base on the subject is limited. Many recognised risk factors for the development of incisional hernia following ostomy reversal are related to patient factors such as age, malignancy, diabetes, COPD, hypertension and obesity, and are not easily correctable. There is a limited amount of evidence to suggest that prophylactic mesh reinforcement may be of benefit to reduce the post stoma closure incisional hernia rate but a further large scale randomised controlled trial is due to report in the near future. There appears to be weak evidence to suggest that surgeons should favour circular, or “purse-string” closure of the skin following stoma closure in order to reduce the risk of SSI, which in turn may reduce incisional hernia formation. There remains the need for further evidence in relation to suture technique, skin closure techniques, mechanical bowel preparation and oral antibiotic prescription focusing on incisional hernia development as an outcome measure. Within this review, we discuss in detail the evidence base for the risk factors for the development of, and the strategies to prevent ostomy reversal site incisional hernias. PMID:29670882

Stomal Closure: Strategies to Prevent Incisional Hernia

Directory of Open Access Journals (Sweden)

Rhiannon L. Harries

2018-04-01

Full Text Available Incisional hernias following ostomy reversal occur frequently. Incisional hernias at the site of a previous stoma closure can cause significant morbidity, impaired quality of life, lead to life-threatening hernia incarceration or strangulation and result in a significant financial burden on health care systems Despite this, the evidence base on the subject is limited. Many recognised risk factors for the development of incisional hernia following ostomy reversal are related to patient factors such as age, malignancy, diabetes, COPD, hypertension and obesity, and are not easily correctable. There is a limited amount of evidence to suggest that prophylactic mesh reinforcement may be of benefit to reduce the post stoma closure incisional hernia rate but a further large scale randomised controlled trial is due to report in the near future. There appears to be weak evidence to suggest that surgeons should favour circular, or “purse-string” closure of the skin following stoma closure in order to reduce the risk of SSI, which in turn may reduce incisional hernia formation. There remains the need for further evidence in relation to suture technique, skin closure techniques, mechanical bowel preparation and oral antibiotic prescription focusing on incisional hernia development as an outcome measure. Within this review, we discuss in detail the evidence base for the risk factors for the development of, and the strategies to prevent ostomy reversal site incisional hernias.

Eigenspace perturbations for structural uncertainty estimation of turbulence closure models

Science.gov (United States)

Jofre, Lluis; Mishra, Aashwin; Iaccarino, Gianluca

2017-11-01

With the present state of computational resources, a purely numerical resolution of turbulent flows encountered in engineering applications is not viable. Consequently, investigations into turbulence rely on various degrees of modeling. Archetypal amongst these variable resolution approaches would be RANS models in two-equation closures, and subgrid-scale models in LES. However, owing to the simplifications introduced during model formulation, the fidelity of all such models is limited, and therefore the explicit quantification of the predictive uncertainty is essential. In such scenario, the ideal uncertainty estimation procedure must be agnostic to modeling resolution, methodology, and the nature or level of the model filter. The procedure should be able to give reliable prediction intervals for different Quantities of Interest, over varied flows and flow conditions, and at diametric levels of modeling resolution. In this talk, we present and substantiate the Eigenspace perturbation framework as an uncertainty estimation paradigm that meets these criteria. Commencing from a broad overview, we outline the details of this framework at different modeling resolution. Thence, using benchmark flows, along with engineering problems, the efficacy of this procedure is established. This research was partially supported by NNSA under the Predictive Science Academic Alliance Program (PSAAP) II, and by DARPA under the Enabling Quantification of Uncertainty in Physical Systems (EQUiPS) project (technical monitor: Dr Fariba Fahroo).

Case Report: Rapid staged abdominal closure using Gore-Tex® mesh as a bridge to primary omphalocele sac closure

Directory of Open Access Journals (Sweden)

William C. Kethman

2016-06-01

Full Text Available Omphaloceles present an ongoing challenge due to significant variations in presentation and associated co-morbidities. Diverse management strategies have been described to tackle many of the fundamental challenges of closure and reconstruction of the abdominal wall – this fact demonstrates a need for increasingly individualized management options for this complex disease. We describe a novel method of rapid staged abdominal wall closure using Gore-Tex® mesh as a bridge to primary omphalocele closure in an infant with partial Pentalogy of Cantrell and giant ruptured omphalocele. This strategy can be used in management of some of the most complex abdominal wall defects.

Bidirectional Barbed Sutures for Wound Closure: Evolution and Applications

Science.gov (United States)

Paul, Malcolm D.

2009-01-01

Traditionally, wound closure sutures have in common the need to tie knots with the inherent risk of extrusion, palpability, microinfarcts, breakage, and slippage. Bidirectional barbed sutures have barbs arrayed in a helical fashion in opposing directions on either side of an unbarbed midsegment. This suture is inserted at the midpoint of a wound and pulled through till resistance is encountered from the opposing barbs; each half of the suture is then advanced to the lateral ends of the wound. This design provides a method of evenly distributing tension along the incision line, a faster suture placement and closure time with no need to tie knots, and the possibility of improved cosmesis. Bidirectional barbed sutures, which are available in both absorbable and nonabsorbable forms, can be used for simple closures, multilayered closures, and closure of high-tension wounds in a variety of surgical settings. PMID:24527114

Primary angle closure glaucoma in a myopic kinship.

Science.gov (United States)

Hagan, J C; Lederer, C M

1985-03-01

Three related myopic individuals with primary angle closure glaucoma are reported. They had true myopia and not pseudomyopia secondary to increased lenticular index of refraction. We believe one of these individuals (-8.62 spherical equivalent) to have the most myopic case of primary angle closure glaucoma reported in the literature. Although myopia is associated with anatomical factors that offer considerable protection from primary angle closure glaucoma, its presence does not eliminate the possibility of this disease. Laser iridectomy was effective in the treatment of these patients.

Closure of a mixed waste landfill: Lessons learned

International Nuclear Information System (INIS)

Phifer, M.A.

1990-01-01

Much experience has been gained during the closure of the Mixed Waste Management Facility (MWMF) at the Savannah River Site (SRS) and many lessons were learned. This knowledge was applied to other closures at SRS yielding decreased costs, schedule enhancement, and increased overall project efficiency. The next major area of experience to be gained at SRS in the field of waste site closures will be in the upkeep, maintenance, and monitoring of clay caps. Further test programs will be required to address these requirements

Influence of Closure & Non-Closure of the Visceral and Parietal Peritoneum on Post Cesarean Morbidity

Directory of Open Access Journals (Sweden)

Tabasi Z.

2010-01-01

Full Text Available AbstractBackground and Objectives: One of the most important issues in promoting mother and child health is reducing the morbidity rate after cesarean section. The aim of this study was to investigate the influence of closure and non-closure of the visceral and parietal peritoneum on post cesarean morbidity in women attending Shabihkhani Maternity Hospital in Kashan, Iran.Methods: This study was conducted with a single blind randomized clinical trial method on 100 parturient women that underwent emergency or elective cesarean section. Patients with previous cesarean section and or abdominal surgery, diseases such as hypertension, diabetes mellitus and premature rupture of membrane and pre operative bleeding, were excluded from this study. Then, the participants were randomly divided into two groups: in one group both peritoneal layers were closed while in the other group, they were not closed. Post operative morbidity including fever, bleeding, post operative pain, analgesic consumption and time of operation were assessed. Data were analyzed with t-tests, and χ2 and a P<0.05 were considered significant.Results: In this study, there were no significant differences between the two groups with respect to age, gestational age, the reason for caesarean section and gravidity, nor were there any differences with respect to the incidence of fever or bleeding and was similar between the two groups, but there was a significant difference between the two groups regarding to feeling of severe pain (P=0.0003, analgesic consumption (P=0.0003 and time of operation (P=0.004. In the non-closure group, dose of analgesic drugs, pain severity and time of operation were less than those of the other group.Conclusion: The Findings showed that non-closure of peritoneal layers as a shorter and simpler procedure has no influence on increasing post cesarean morbidity. Therefore, due to maternal health promotion and early neonatal breastfeeding, non closure of peritoneal

A refined safety analysis approach for closure of the Hanford Site flammable gas unreviewed safety question

International Nuclear Information System (INIS)

Bratzel, D.R.

1997-01-01

Following a 1990 investigation into flammable gas generation, retention, and release mechanisms within the Hanford Site high-level waste tanks, personnel concluded that the existing Authorization Basis documentation did not adequately evaluate flammable gas hazards. This declaration was based primarily on the fact that personnel did not adequately consider hydrogen and nitrous oxide evolution within the material in certain waste tanks and subsequent hypothetical ignition in the development of safety documentation for the waste tanks. The US Department of Energy-Headquarters subsequently declared an Unreviewed Safety Question (USQ). Although work scope has been focused on closure of the USQ since 1990, the DOE has yet to close the USQ because of considerable uncertainty regarding essential technical parameters and associated risk. The DOE recently approved a Basis for Interim Operation to revise the Authorization Basis for managing the tank farms, however, the USQ remains open. The two fundamental requirements for closure of the flammable gas USQ are as follows: development of a defensible technical basis for existing controls; development of a process to assess the adequacy of controls as the waste tank mission progresses

Numerical modeling of underground openings behavior with a viscoplastic approach

International Nuclear Information System (INIS)

Kleine, A.

2007-01-01

Nature is complex and must be approached in total modesty by engineers seeking to predict the behavior of underground openings. The engineering of industrial projects in underground situations, with high economic and social stakes (Alpine mountain crossings, nuclear waste repository), mean striving to gain better understanding of the behavioral mechanisms of the openings to be designed. This improvement necessarily involves better physical representativeness of macroscopic mechanisms and the provision of prediction tools suited to the expectations and needs of the engineers. The calculation tools developed in this work is in step with this concern for satisfying industrial needs and developing knowledge related to the rheology of geo-materials. These developments led to the proposing of a mechanical constitutive model, suited to lightly fissured rocks, comparable to continuous media, while integrating more particularly the effect of time. Thread of this study, the problematics ensued from the subject of the thesis is precisely about the rock mass delayed behavior in numerical modeling and its consequences on underground openings design. Based on physical concepts of reference, defined in several scales (macro/meso/micro), the developed constitutive model is translated in a mathematical formalism in order to be numerically implemented. Numerical applications presented as illustrations fall mainly within the framework of nuclear waste repository problems. They concern two very different configurations of underground openings: the AECL's underground canadian laboratory, excavated in the Lac du Bonnet granite, and the GMR gallery of Bure's laboratory (Meuse/Haute-Marne), dug in argillaceous rock. In this two cases, this constitutive model use highlights the gains to be obtained from allowing for delayed behavior regarding the accuracy of numerical tunnel behavior predictions in the short, medium and long terms. (author)

Monitoring calculation of closure change of Extradosed Cable-stayed Bridge

Science.gov (United States)

Shi, Jing Xian; Ran, Zhi Hong

2018-06-01

During the construction of extradosed cable-stayed bridge in Yunnan province, China, the construction unit has made certain changes in the construction process of the closure section due to environmental restrictions: remove the hanging basket after the closure, the sling shall not be provided in closure section, the function of the sling is realized by the hanging basket on the 16th beam. In case of this change, the bridge has been constructed to section 15th. In order to ensure the smooth and orderly progress of each stage in the closure phase, this article is arranged according to the construction plan, appropriate adjustment of related procedures, checking the bridge safety at all stages of construction, the stress and force of the main girder are compared to ensure the safety of the construction after closure changes. Adjust the height of the beam of the 16th and 17th to adapt the new construction plan, and the bridge closure smoothly.

Non-Markovian closure models for large eddy simulations using the Mori-Zwanzig formalism

Science.gov (United States)

Parish, Eric J.; Duraisamy, Karthik

2017-01-01

This work uses the Mori-Zwanzig (M-Z) formalism, a concept originating from nonequilibrium statistical mechanics, as a basis for the development of coarse-grained models of turbulence. The mechanics of the generalized Langevin equation (GLE) are considered, and insight gained from the orthogonal dynamics equation is used as a starting point for model development. A class of subgrid models is considered which represent nonlocal behavior via a finite memory approximation [Stinis, arXiv:1211.4285 (2012)], the length of which is determined using a heuristic that is related to the spectral radius of the Jacobian of the resolved variables. The resulting models are intimately tied to the underlying numerical resolution and are capable of approximating non-Markovian effects. Numerical experiments on the Burgers equation demonstrate that the M-Z-based models can accurately predict the temporal evolution of the total kinetic energy and the total dissipation rate at varying mesh resolutions. The trajectory of each resolved mode in phase space is accurately predicted for cases where the coarse graining is moderate. Large eddy simulations (LESs) of homogeneous isotropic turbulence and the Taylor-Green Vortex show that the M-Z-based models are able to provide excellent predictions, accurately capturing the subgrid contribution to energy transfer. Last, LESs of fully developed channel flow demonstrate the applicability of M-Z-based models to nondecaying problems. It is notable that the form of the closure is not imposed by the modeler, but is rather derived from the mathematics of the coarse graining, highlighting the potential of M-Z-based techniques to define LES closures.

Speckle-Tracking Echocardiography in Dogs With Patent Ductus Arteriosus: Effect of Percutaneous Closure on Cardiac Mechanics.

Science.gov (United States)

Spalla, I; Locatelli, C; Zanaboni, A M; Brambilla, P; Bussadori, C

2016-05-01

Patent ductus arteriosus (PDA) is 1 of the most common congenital heart defects in dogs and percutaneous closure is effective in achieving ductal closure; PDA closure is associated with abrupt hemodynamic changes. A marked decrease in standard parameters of systolic function as assessed by M- or B-mode echocardiography after PDA closure was identified in previous studies. Speckle tracking echocardiography can provide further insight into the effect of PDA closure on cardiac mechanics in dogs affected by PDA. Twenty-five client-owned dogs with PDA. Prospective study. Dogs were recruited over a 2-year period. Complete echocardiographic evaluation was performed before and 24 hours after PDA closure, including standard (end-diastolic volumes indexed to body surface area in B- and M-mode [EDVIB /M ], end-systolic volumes indexed to body surface area in B- and M-mode [ESVIB /M ], allometric scaling in diastole [AlloD] and systole [AlloS], pulmonary flow to systemic flow [Qs/Qp], ejection fraction [EF], and fractional shortening [FS]), and advanced speckle-tracking echocardiography (STE): global longitudinal, radial, circumferential and transverse strain (S), and strain rate (SR). Patent ductus arteriosus closure was associated with statistically significant decreases in EDVIM /B and ESVIM /B , AlloD and AlloS, SI, EF, and FS. A statistically significant decrease in the absolute values of radial, transverse, and circumferential S and SR was observed, whereas longitudinal S and SR did not change significantly. Patent ductus arteriosus closure by percutaneous approach is associated with marked decreases of conventional echocardiographic parameters as a result of the changes in loading conditions, but no evidence of systolic dysfunction was identified by means of STE, as none of the S and SR values were below reference ranges. In the short term, contractility is enhanced in the long axis (long S/SR values were not statistically different before and after closure) and

NUMERICAL SIMULATION OF ELECTRICAL IMPEDANCE TOMOGRAPHY PROBLEM AND STUDY OF APPROACH BASED ON FINITE VOLUME METHOD

Directory of Open Access Journals (Sweden)

Ye. S. Sherina

2014-01-01

Full Text Available This research has been aimed to carry out a study of peculiarities that arise in a numerical simulation of the electrical impedance tomography (EIT problem. Static EIT image reconstruction is sensitive to a measurement noise and approximation error. A special consideration has been given to reducing of the approximation error, which originates from numerical implementation drawbacks. This paper presents in detail two numerical approaches for solving EIT forward problem. The finite volume method (FVM on unstructured triangular mesh is introduced. In order to compare this approach, the finite element (FEM based forward solver was implemented, which has gained the most popularity among researchers. The calculated potential distribution with the assumed initial conductivity distribution has been compared to the analytical solution of a test Neumann boundary problem and to the results of problem simulation by means of ANSYS FLUENT commercial software. Two approaches to linearized EIT image reconstruction are discussed. Reconstruction of the conductivity distribution is an ill-posed problem, typically requiring a large amount of computation and resolved by minimization techniques. The objective function to be minimized is constructed of measured voltage and calculated boundary voltage on the electrodes. A classical modified Newton type iterative method and the stochastic differential evolution method are employed. A software package has been developed for the problem under investigation. Numerical tests were conducted on simulated data. The obtained results could be helpful to researches tackling the hardware and software issues for medical applications of EIT.

MNC Subsidiary Closures

DEFF Research Database (Denmark)

Sofka, Wolfgang; Torres Preto, Miguel; de Faria, Pedro

2014-01-01

We investigate the consequences of MNC subsidiary closures for employees who lose their jobs. In particular, we examine the extent to which the human capital that these employees acquired while employed by the MNC influences the wages they receive in their new jobs. We propose an employee...

Initial experience with the Cardiva Boomerang vascular closure device in diagnostic catheterization.

Science.gov (United States)

Doyle, Brendan J; Godfrey, Michael J; Lennon, Ryan J; Ryan, James L; Bresnahan, John F; Rihal, Charanjit S; Ting, Henry H

2007-02-01

The authors studied the safety and efficacy of the Cardiva Boomerang vascular closure device in patients undergoing diagnostic cardiac catheterization. Conventional vascular closure devices (sutures, collagen plugs, or metal clips) have been associated with catastrophic complications including arterial occlusion and foreign body infections; furthermore, they cannot be utilized in patients with peripheral vascular disease or vascular access site in a vessel other than the common femoral artery. The Cardiva Boomerang device facilitates vascular hemostasis without leaving any foreign body behind at the access site, can be used in peripheral vascular disease, and can be used in vessels other than the common femoral artery A total of 96 patients undergoing transfemoral diagnostic cardiac catheterization were included in this study, including 25 (26%) patients with contraindications to conventional closure devices. Femoral angiography was performed prior to deployment of the Cardiva Boomerang closure device. Patients were ambulated at 1 hr after hemostasis was achieved. The device was successfully deployed and hemostasis achieved with the device alone in 95 (99%) patients. The device failed to deploy in 1 (1%) patient and required conversion to standard manual compression. Minor complications were observed in 5 (5%) patients. No patients experienced major complications including femoral hematoma > 4 cm, red blood cell transfusion, retroperitoneal bleed, arteriovenous fistula, pseudoaneurysm, infection, arterial occlusion, or vascular surgery. The Cardiva Boomerang device is safe and effective in patients undergoing diagnostic cardiac catheterization using the transfemoral approach, facilitating early ambulation with low rates of vascular complications. (c) 2006 Wiley-Liss, Inc.

A method for evaluating basement exhumation histories from closure age distributions of detrital minerals

International Nuclear Information System (INIS)

Lovera, Oscar M.; Grove, Marty; Kimbrough, David L.; Abbott, Patrick L.

1999-01-01

We have developed a two-dimensional, thermokinetic model that predicts the closure age distributions of detrital minerals from pervasively intruded and differentially exhumed basement. Using this model, we outline a method to determine the denudation history of orogenic regions on the basis of closure age distributions in synorogenic to postorogenic forearc strata. At relatively high mean denudation rates of 0.5 km m.y.-1 sustained over millions of years, magmatic heating events have minimal influence upon the age distributions of detrital minerals such as K-feldspar that are moderately retentive of radiogenic Ar. At lower rates, however, the effects of batholith emplacement may be substantial. We have applied the approach to detrital K-feldspars from forearc strata derived from the deeply denuded Peninsular Ranges batholith (PRB). Agreement of the denudation history deduced from the detrital K-feldspar data with thermochronologic constraints from exposed PRB basement lead us to conclude that exhumation histories of magmatic arcs should be decipherable solely from closure age distributions of detrital minerals whose depositional age is known. (c) 1999 American Geophysical Union

Improvement of tricuspid regurgitation after transcatheter ASD closure in older patients.

Science.gov (United States)

Chen, L; Shen, J; Shan, X; Wang, F; Kan, T; Tang, X; Zhao, X; Qin, Y

2017-07-19

Adult patients with undiagnosed atrial septal defect (ASD) may have right heart cavity enlargement and functional tricuspid valve insufficiency. Moderate or more severe tricuspid regurgitation has been associated with a worse prognosis, and more serious complications are typically seen in older patients. This study aimed to evaluate the improvement in functional tricuspid regurgitation and heart geometry after transcatheter ASD closure in older patients. The data of 111 patients over 60 years of age with moderate or severe tricuspid regurgitation before ASD closure were analyzed. At the 1‑month and 6‑month follow-up after closure, both tricuspid regurgitation jet area and right atrial volume decreased significantly. Right ventricular volume decreased 1 month after closure, showing a further decrease at the end of the 6‑month follow-up. However, 24 patients (21.6%) still had persistent severe tricuspid regurgitation after the procedure. Multivariate analysis revealed that patient age at ASD closure and pulmonary artery systolic pressure determined by echocardiography before closure were predictors of persistent tricuspid regurgitation after closure. Transcatheter ASD closure in older patients could significantly decrease tricuspid regurgitation and improve right heart geometry.

2727-S Nonradioactive Dangerous Waste Storage Facility clean closure evaluation report

International Nuclear Information System (INIS)

Luke, S.N.

1994-01-01

This report presents the analytical results of 2727-S NRDWS facility closure verification soil sampling and compares these results to clean closure criteria. The results of this comparison will determine if clean closure of the unit is regulatorily achievable. This report also serves to notify regulators that concentrations of some analytes at the site exceed sitewide background threshold levels (DOE-RL 1993b) and/or the limits of quantitation (LOQ). This report also presents a Model Toxics Control Act Cleanup (MTCA) (WAC 173-340) regulation health-based closure standard under which the unit can clean close in lieu of closure to background levels or LOQ in accordance with WAC 173-303-610. The health-based clean closure standard will be closure to MTCA Method B residential cleanup levels. This report reconciles all analyte concentrations reported above background or LOQ to this health-based cleanup standard. Regulator acceptance of the findings presented in this report will qualify the TSD unit for clean closure in accordance with WAC 173-303-610 without further TSD unit soil sampling, or soil removal and/or decontamination. Nondetected analytes require no further evaluation

A finite difference, multipoint flux numerical approach to flow in porous media: Numerical examples

KAUST Repository

Osman, Hossam Omar; Salama, Amgad; Sun, Shuyu; Bao, Kai

2012-01-01

It is clear that none of the current available numerical schemes which may be adopted to solve transport phenomena in porous media fulfill all the required robustness conditions. That is while the finite difference methods are the simplest of all, they face several difficulties in complex geometries and anisotropic media. On the other hand, while finite element methods are well suited to complex geometries and can deal with anisotropic media, they are more involved in coding and usually require more execution time. Therefore, in this work we try to combine some features of the finite element technique, namely its ability to work with anisotropic media with the finite difference approach. We reduce the multipoint flux, mixed finite element technique through some quadrature rules to an equivalent cell-centered finite difference approximation. We show examples on using this technique to single-phase flow in anisotropic porous media.

A finite difference, multipoint flux numerical approach to flow in porous media: Numerical examples

KAUST Repository

Osman, Hossam Omar

2012-06-17

It is clear that none of the current available numerical schemes which may be adopted to solve transport phenomena in porous media fulfill all the required robustness conditions. That is while the finite difference methods are the simplest of all, they face several difficulties in complex geometries and anisotropic media. On the other hand, while finite element methods are well suited to complex geometries and can deal with anisotropic media, they are more involved in coding and usually require more execution time. Therefore, in this work we try to combine some features of the finite element technique, namely its ability to work with anisotropic media with the finite difference approach. We reduce the multipoint flux, mixed finite element technique through some quadrature rules to an equivalent cell-centered finite difference approximation. We show examples on using this technique to single-phase flow in anisotropic porous media.

Shell closures, loosely bound structures, and halos in exotic nuclei

International Nuclear Information System (INIS)

Saxena, G.; Singh, D.

2013-01-01

Inspired by the recent experiments indicating doubly magic nuclei that lie near the drip-line and encouraged by the success of our relativistic mean-field (RMF) plus state-dependent BCS approach to the description of the ground-state properties of drip-line nuclei, we develop this approach further, across the entire periodic table, to explore magic nuclei, loosely bound structures, and halo formation in exotic nuclei. In our RMF+BCS approach, the single-particle continuum corresponding to the RMF is replaced by a set of discrete positive-energy states for the calculations of pairing energy. Detailed analysis of the single-particle spectrum, pairing energies, and densities of the nuclei predict the unusual proton shell closures at proton numbers Z = 6, 14, 16, 34, and unusual neutron shell closures at neutron numbers N = 6, 14, 16, 34, 40, 70, 112. Further, in several nuclei like the neutron-rich isotopes of Ca, Zr, Mo, etc., the gradual filling of lowlying single-particle resonant state together with weakly bound single-particle states lying close to the continuum threshold helps accommodate more neutrons but with an extremely small increase in the binding energy. This gives rise to the occurrence of loosely bound systems of neutron-rich nuclei with a large neutron-to-proton ratio. In general, the halo-like formation, irrespective of the existence of any resonant state, is seen to be due to the large spatial extension of the wave functions for the weakly bound single-particle states with low orbital angular momentum having very small or no centrifugal barriers.

Shell closures, loosely bound structures, and halos in exotic nuclei

Energy Technology Data Exchange (ETDEWEB)

Saxena, G., E-mail: gauravphy@gmail.com [Govt. Women Engineering College, Department of Physics (India); Singh, D. [University of Rajasthan, Department of Physics (India)

2013-04-15

Inspired by the recent experiments indicating doubly magic nuclei that lie near the drip-line and encouraged by the success of our relativistic mean-field (RMF) plus state-dependent BCS approach to the description of the ground-state properties of drip-line nuclei, we develop this approach further, across the entire periodic table, to explore magic nuclei, loosely bound structures, and halo formation in exotic nuclei. In our RMF+BCS approach, the single-particle continuum corresponding to the RMF is replaced by a set of discrete positive-energy states for the calculations of pairing energy. Detailed analysis of the single-particle spectrum, pairing energies, and densities of the nuclei predict the unusual proton shell closures at proton numbers Z = 6, 14, 16, 34, and unusual neutron shell closures at neutron numbers N = 6, 14, 16, 34, 40, 70, 112. Further, in several nuclei like the neutron-rich isotopes of Ca, Zr, Mo, etc., the gradual filling of lowlying single-particle resonant state together with weakly bound single-particle states lying close to the continuum threshold helps accommodate more neutrons but with an extremely small increase in the binding energy. This gives rise to the occurrence of loosely bound systems of neutron-rich nuclei with a large neutron-to-proton ratio. In general, the halo-like formation, irrespective of the existence of any resonant state, is seen to be due to the large spatial extension of the wave functions for the weakly bound single-particle states with low orbital angular momentum having very small or no centrifugal barriers.

Self-corrective T-loop design for differential space closure.

Science.gov (United States)

Viecilli, Rodrigo F

2006-01-01

The current approach to measuring T-loop force systems in patients requiring differential anchorage does not consider active unit angulations and steps during space closure. The angulations and steps during movement introduced by rotation can considerably modify the force system acting on the teeth. In this study, geometric modifications were determined during controlled tipping of the 6 anterior teeth, where there was no movement of the posterior teeth, thus configuring a type A anchorage situation. An optimal beta-titanium alloy 0.017 x 0.025-in T-loop spring was designed by using a simulation performed with LOOP software (dHAL Orthodontic Software, Athens, Greece) to allow compensation for anterior unit-position effect on the final force system. The force systems produced by this T-loop spring with and without geometric correction of the brackets have significant differences that should be considered in the segmented arch approach to space closure. The effects of steps, angles, and vertical forces were combined to produce an ideal T-loop design that would provide a more determinate force system. The effects and force systems are estimates based on simplified locations of the centers of resistance, assuming relatively constant behavior of the centers of rotation. These simplifications might differ slightly from what happens in vivo. The finite element method or an accurate spring tester capable of reproducing the geometric corrections should be used to ensure a precise force system.

Significant skin-tightening by closure of fractional ablative laser holes.

Science.gov (United States)

Russe, Elisabeth; Purschke, Martin; Limpiangkanan, Wikunda; Farinelli, William A; Wang, Ying; Doukas, Apostolos G; Sakamoto, Fernanda H; Wechselberger, Gottfried; Anderson, Richard Rox

2018-01-01

and needle coring treatment without closure did not result in significant area reduction (P = 0.1289) compared with untreated control sites. Significant skin tightening can be achieved by immediate temporary non-invasive wound closure after short pulse Er:YAG fractional ablative laser treatment, as well as after mechanically removing skin with a coring needle. This approach may improve skin tightening after ablative laser treatments. Further clinical studies are necessary to confirm successful application in humans. Lasers Surg. Med. 50:64-69, 2018. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Waste Dump Closure and Cost Estimates at AngloGold Ashanti ...

African Journals Online (AJOL)

Michael

2017-12-02

Dec 2, 2017 ... 2University of Mines and Technology, P.O. Box 237, Tarkwa, Ghana ... The mine has closure plans for the waste dumps and the closure activity ... incur additional cost, it was advised that the mine should execute the closure and reclamation plan without delay. .... Progressively rehabilitate the project area.

A short summary on finite element modelling of fatigue crack closure

Energy Technology Data Exchange (ETDEWEB)

Singh, Konjengbam Darunkumar [Indian Institute of Technology, Guwahati (India); Parry, Matthew Roger [Airbus Operations Ltd, Bristol(United Kingdom); Sinclair, Ian [University of Southampton, Southampton (United Kingdom)

2011-12-15

This paper presents a short summary pertaining to the finite element modelling of fatigue crack closure. Several key issues related to finite element modelling of fatigue crack closure are highlighted: element type, mesh refinement, stabilization of crack closure, crack-tip node release scheme, constitutive model, specimen geometry, stress-states (i.e., plane stress, plane strain), crack closure monitoring. Reviews are presented for both straight and deflected cracks.

Staged closure of a giant omphalocele with amnion preservation, modified technique

Directory of Open Access Journals (Sweden)

Akram H. Aljahdali

2017-04-01

Full Text Available Closure of a giant omphalocele can be challenging. Preservation of the amnion in staged closure is not commonly practiced. Here, we describe 2 cases of giant omphalocele treated with a modified amnion preservation, staged closure technique. This paper demonstrates the feasibility and safety of this technique, and the versatility of amnion to adapt to an escharization strategy if closure is not achievable.

Factors associated with supermarket and convenience store closure: a discrete time spatial survival modelling approach.

Science.gov (United States)

Warren, Joshua L; Gordon-Larsen, Penny

2018-06-01

While there is a literature on the distribution of food stores across geographic and social space, much of this research uses cross-sectional data. Analyses attempting to understand whether the availability of stores across neighborhoods is associated with diet and/or health outcomes are limited by a lack of understanding of factors that shape the emergence of new stores and the closure of others. We used quarterly data on supermarket and convenience store locations spanning seven years (2006-2012) and tract-level census data in four US cities: Birmingham, Alabama; Chicago, Illinois; Minneapolis, Minnesota; San Francisco, California. A spatial discrete-time survival model was used to identify factors associated with an earlier and/or later closure time of a store. Sales volume was typically the strongest indicator of store survival. We identified heterogeneity in the association between tract-level poverty and racial composition with respect to store survival. Stores in high poverty, non-White tracts were often at a disadvantage in terms of survival length. The observed patterns of store survival varied by some of the same neighborhood sociodemographic factors associated with lifestyle and health outcomes, which could lead to confusion in interpretation in studies of the estimated effects of introduction of food stores into neighborhoods on health.

A numerical approach to the simulation of one-phase and two phase reactor coolant flow around nuclear fuel spacers

International Nuclear Information System (INIS)

Stosic, Z.V.; Stevanovic, V.D.

2001-01-01

A methodology for the simulation and analysis of one-phase and two-phase coolant flows around one or a row of spacers is presented. It is based on the multidimensional two-fluid mass, momentum and energy balance equations and application of adequate turbulence models. Necessary closure laws for interfacial transfer processes are presented. The stated general approach enables simulation and analyses of reactor coolant flow around spacers on different scale levels of the rod bundle geometry: detailed modelling of coolant flow around spacers and investigation of the influence of spacer's geometry on the coolant thermal-hydraulics, as well as prediction of global thermal-hydraulic parameters within the whole rod bundle with the investigation of the influence of rows of spacers on the bulk thermal-hydraulic processes. Sample problems are included illustrating these different modelling approaches. (author)

Segmentation and Quantification for Angle-Closure Glaucoma Assessment in Anterior Segment OCT.

Science.gov (United States)

Fu, Huazhu; Xu, Yanwu; Lin, Stephen; Zhang, Xiaoqin; Wong, Damon Wing Kee; Liu, Jiang; Frangi, Alejandro F; Baskaran, Mani; Aung, Tin

2017-09-01

Angle-closure glaucoma is a major cause of irreversible visual impairment and can be identified by measuring the anterior chamber angle (ACA) of the eye. The ACA can be viewed clearly through anterior segment optical coherence tomography (AS-OCT), but the imaging characteristics and the shapes and locations of major ocular structures can vary significantly among different AS-OCT modalities, thus complicating image analysis. To address this problem, we propose a data-driven approach for automatic AS-OCT structure segmentation, measurement, and screening. Our technique first estimates initial markers in the eye through label transfer from a hand-labeled exemplar data set, whose images are collected over different patients and AS-OCT modalities. These initial markers are then refined by using a graph-based smoothing method that is guided by AS-OCT structural information. These markers facilitate segmentation of major clinical structures, which are used to recover standard clinical parameters. These parameters can be used not only to support clinicians in making anatomical assessments, but also to serve as features for detecting anterior angle closure in automatic glaucoma screening algorithms. Experiments on Visante AS-OCT and Cirrus high-definition-OCT data sets demonstrate the effectiveness of our approach.

A data-driven analysis of energy balance closure across FLUXNET research sites: The role of landscape scale heterogeneity

DEFF Research Database (Denmark)

Stoy, Paul C.; Mauder, Matthias; Foken, Thomas

2013-01-01

approached 1. These results suggest that landscape-level heterogeneity in vegetation and topography cannot be ignored as a contributor to incomplete energy balance closure at the flux network level, although net radiation measurements, biological energy assimilation, unmeasured storage terms......The energy balance at most surface-atmosphere flux research sites remains unclosed. The mechanisms underlying the discrepancy between measured energy inputs and outputs across the global FLUXNET tower network are still under debate. Recent reviews have identified exchange processes and turbulent...... motions at large spatial and temporal scales in heterogeneous landscapes as the primary cause of the lack of energy balance closure at some intensively-researched sites, while unmeasured storage terms cannot be ruled out as a dominant contributor to the lack of energy balance closure at many other sites...

Closure Report for Corrective Action Unit 118: Area 27 Super Kukla Facility, Nevada Test Site, Nevada, Revision 0

International Nuclear Information System (INIS)

Mark Burmeister

2007-01-01

This CR provides documentation and justification for the closure of CAU 118 without further corrective action. This justification is based on process knowledge and the results of the investigative and closure activities conducted in accordance with the CAU 118 SAFER Plan: Streamlined Approach for Environmental Restoration (SAFER) Plan for CAU 118: Area 27 Super Kukla Facility, Nevada Test Site, Nevada (NNSA/NSO, 2006). The SAFER Plan provides information relating to site history as well as the scope and planning of the investigation. This CR also provides the analytical and radiological survey data to confirm that the remediation goals were met as specified in the CAU 118 SAFER Plan (NNSA/NSO, 2006). The Nevada Division of Environmental Protection (NDEP) approved the CAU 118 SAFER Plan (Murphy, 2006), which recommends closure in place with use restrictions (URs)

DESIGN OF A WELDING AND INSPECTION SYSTEM FOR WASTE STORAGE CLOSURE

International Nuclear Information System (INIS)

H.B. Smartt; A.D. Watkins; D.P. Pace; R.J. Bitsoi; E.D. Larsen T.R. McJunkin; C.R. Tolle

2005-01-01

This work reported here was done to provide a conceptual design for a robotic welding and inspection system for the Yucca Mountain Repository waste package closure system. The welding and inspection system is intended to make the various closure welds that seal and/or structurally join the lids to the waste package vessels. The welding and inspection system will also perform surface and volumetric inspections of the various closure welds and has the means to repair closure welds, if required. The system is designed to perform these various activities remotely, without the necessity of having personnel in the closure cell

Friction or Closure

DEFF Research Database (Denmark)

Lundahl, Mikela

2014-01-01

Heritage is a discourse that aims at closure. It fixates the narrative of the past through the celebration of specific material (or sometimes immaterial non-) ob-jects. It organizes temporality and construct events and freezes time. How does this unfold in the case of the UNESCO World Heritage si...

Multipass mining sequence room closures: In situ data report

International Nuclear Information System (INIS)

Munson, D.E.; Jones, R.L.; Northrop-Salazar, C.L.; Woerner, S.J.

1992-12-01

During the construction of the Thermal/Structural In Situ Test Rooms at the Waste Isolation Pilot Plant (WIPP) facility, measurements of the salt displacements were obtained at very early times, essentially concurrent with the mining activity. This was accomplished by emplacing manually read closure gage stations directly at the mining face, actually between the face and the mining machine, immediately upon mining of the intended gage location. Typically, these mining sequence closure measurements were taken within one hour of mining of the location and within one meter of the mining face. Readings were taken at these gage stations as the multipass mining continued, with the gage station reestablished as each successive mining pass destroyed the earlier gage points. Data reduction yields the displacement history during the mining operation. These early mining sequence closure data, when combined with the later data of the permanently emplaced closure gages, gives the total time-dependent closure displacements of the test rooms. This complete closure history is an essential part of assuring that the in situ test databases will provide an adequate basis for validation of the predictive technology of salt creep behavior, as required by the WIPP technology development program for disposal of radioactive waste in bedded salt

Susy theories and QCD: numerical approaches

International Nuclear Information System (INIS)

Ita, Harald

2011-01-01

We review on-shell and unitarity methods and discuss their application to precision predictions for Large Hadron Collider (LHC) physics. Being universal and numerically robust, these methods are straightforward to automate for next-to-leading-order computations within standard model and beyond. Several state-of-the-art results including studies of (W/Z+3)-jet and (W+4)-jet production have explicitly demonstrated the effectiveness of the unitarity method for describing multi-parton scattering. Here we review central ideas needed to obtain efficient numerical implementations. This includes on-shell loop-level recursions, the unitarity method, color management and further refined tricks. (review)

Monte Carlo closure for moment-based transport schemes in general relativistic radiation hydrodynamic simulations

Science.gov (United States)

Foucart, Francois

2018-04-01

General relativistic radiation hydrodynamic simulations are necessary to accurately model a number of astrophysical systems involving black holes and neutron stars. Photon transport plays a crucial role in radiatively dominated accretion discs, while neutrino transport is critical to core-collapse supernovae and to the modelling of electromagnetic transients and nucleosynthesis in neutron star mergers. However, evolving the full Boltzmann equations of radiative transport is extremely expensive. Here, we describe the implementation in the general relativistic SPEC code of a cheaper radiation hydrodynamic method that theoretically converges to a solution of Boltzmann's equation in the limit of infinite numerical resources. The algorithm is based on a grey two-moment scheme, in which we evolve the energy density and momentum density of the radiation. Two-moment schemes require a closure that fills in missing information about the energy spectrum and higher order moments of the radiation. Instead of the approximate analytical closure currently used in core-collapse and merger simulations, we complement the two-moment scheme with a low-accuracy Monte Carlo evolution. The Monte Carlo results can provide any or all of the missing information in the evolution of the moments, as desired by the user. As a first test of our methods, we study a set of idealized problems demonstrating that our algorithm performs significantly better than existing analytical closures. We also discuss the current limitations of our method, in particular open questions regarding the stability of the fully coupled scheme.

300 Area waste acid treatment system closure plan

International Nuclear Information System (INIS)

LUKE, S.N.

1999-01-01

The Hanford Facility Dangerous Waste Permit Application is considered to be a single application organized into a General Information Portion (document number DOERL-91-28) and a Unit-Specific Portion. The scope of the Unit-Specific Portion includes closure plan documentation submitted for individual, treatment, storage, and/or disposal units undergoing closure, such as the 300 Area Waste Acid Treatment System. Documentation contained in the General Information Portion is broader in nature and could be used by multiple treatment, storage, and/or disposal units (e.g., the glossary provided in the General Information Portion). Whenever appropriate, 300 Area Waste Acid Treatment System documentation makes cross-reference to the General Information Portion, rather than duplicating text. This 300 Area Waste Acid Treatment System Closure Plan (Revision 2) includes a Hanford Facility Dangerous Waste Permit Application, Part A, Form 3. Information provided in this closure plan is current as of April 1999

300 Area waste acid treatment system closure plan

Energy Technology Data Exchange (ETDEWEB)

LUKE, S.N.

1999-05-17

The Hanford Facility Dangerous Waste Permit Application is considered to be a single application organized into a General Information Portion (document number DOERL-91-28) and a Unit-Specific Portion. The scope of the Unit-Specific Portion includes closure plan documentation submitted for individual, treatment, storage, and/or disposal units undergoing closure, such as the 300 Area Waste Acid Treatment System. Documentation contained in the General Information Portion is broader in nature and could be used by multiple treatment, storage, and/or disposal units (e.g., the glossary provided in the General Information Portion). Whenever appropriate, 300 Area Waste Acid Treatment System documentation makes cross-reference to the General Information Portion, rather than duplicating text. This 300 Area Waste Acid Treatment System Closure Plan (Revision 2) includes a Hanford Facility Dangerous Waste Permit Application, Part A, Form 3. Information provided in this closure plan is current as of April 1999.

Predictors of successful closure of patent ductus arteriosus with indomethacin.

Science.gov (United States)

Ahamed, M F; Verma, P; Lee, S; Vega, M; Wang, D; Kim, M; Fuloria, M

2015-09-01

To determine whether platelet counts can predict the likelihood of successful closure of patent ductus arteriosus (PDA) with indomethacin. This was a retrospective cohort study of infants closure with indomethacin and those who failed were compared. Multivariable logistic regression was used to identify predictors of successful ductal closure. In infants with hemodynamically significant PDA, older GA (odds ratio=1.54; 95% confidence interval: 1.12 to 2.13), male gender (odds ratio=3.02; 95% confidence interval: 1.08 to 8.49) and higher platelet count (odds ratio=1.5; 95% confidence interval: 1.04 to 2.17) prior to indomethacin treatment were associated with successful ductal closure with indomethacin. Older GA, male gender and higher platelet count at time of treatment of hemodynamically significant PDA are predictors of successful ductal closure with indomethacin.

300 Area Process Trenches Closure Plan

International Nuclear Information System (INIS)

Luke, S.N.

1994-01-01

Since 1987, Westinghouse Hanford Company has been a major contractor to the US Department of Energy, Richland Operations Office and has served as co-operator of the 300 Area Process Trenches, the waste management unit addressed in this closure plan. For the purposes of the Resource Conservation and Recovery Act, Westinghouse Hanford Company is identified as ''co-operator.'' The 300 Area Process Trenches Closure Plan (Revision 0) consists of a Resource Conservation and Recovery Act Part A Dangerous Waste Permit Application, Form 3 and a Resource Conservation and Recovery Act Closure Plan. An explanation of the Part A Permit Application, Form 3 submitted with this document is provided at the beginning of the Part A Section. The closure plan consists of nine chapters and six appendices. The 300 Area Process Trenches received dangerous waste discharges from research and development laboratories in the 300 Area and from fuels fabrication processes. This waste consisted of state-only toxic (WT02), corrosive (D002), chromium (D007), spent halogenated solvents (F001, F002, and F003), and spent nonhalogented solvent (F005). Accurate records are unavailable concerning the amount of dangerous waste discharged to the trenches. The estimated annual quantity of waste (item IV.B) reflects the total quantity of both regulated and nonregulated waste water that was discharged to the unit

Catheter-based closure of the patent ductus arteriosus in lower weight infants.

Science.gov (United States)

Pavlek, Leeann R; Slaughter, Jonathan L; Berman, Darren P; Backes, Carl H

2018-06-13

Risks associated with drug therapy and surgical ligation have led health care providers to consider alternative strategies for patent ductus arteriosus (PDA) closure. Catheter-based PDA closure is the procedure of choice for ductal closure in adults, children, and infants ≥6kg. Given evidence among older counterparts, interest in catheter-based closure of the PDA in lower weight (closure devices; (3) review the technical success (feasibility); (4) review the risks (safety profile); (5) discuss the quality of evidence on procedural efficacy; (6) consider areas for future research. The review provided herein suggests that catheter-based PDA closure is technically feasible, but the lack of comparative trials precludes determination of the optimal strategy for ductal closure in this subgroup of infants. Copyright © 2018 Elsevier Inc. All rights reserved.

Oral Paracetamol for Patent Ductus Arteriosus Rescue Closure.

Science.gov (United States)

Pharande, Pramod; Watson, Hadley; Tan, Kenneth; Sehgal, Arvind

2018-01-01

The objective of this study was to ascertain the efficacy of oral paracetamol in closing a symptomatic patent ductus arteriosus (PDA) when used as 'rescue' option. After obtaining ethics approval, a retrospective appraisal of the data from April 2014 to July 2015 was performed. Infants who were administered oral paracetamol either after unsuccessful therapy with ibuprofen or where it was considered contraindicated were included. A previously published echocardiographic scoring schema to stratify for ductal disease severity was used. Using univariate analysis, characteristics of infants with successful closure were compared with partial (a priori reduction in composite score by ≥ 50% of pretreatment) or no closure. Twenty infants with gestation age and birthweight of 25.7 ± 1.5 weeks and 724.1 ± 143 g, respectively, were studied. Complete closure was noted in 10 (50%) infants with additional four infants showing a significant reduction in haemodynamic shunting. Gestational age at birth and at therapy, chronological age at therapy, birthweight and total fluid intake were comparable between the two groups. The pre-therapy composite score had a significant association with successful closure (the higher the echocardiographic score, the lesser the closure). Concomitant furosemide therapy and late-onset sepsis had a high likelihood ratio of unsuccessful closure (11.01 [2-tailed, p = 0.005] and 5.3 [2-tailed, p = 0.07]), respectively. Oral paracetamol may be a possible therapeutic option in premature infants where therapy with first-line agents is unsuccessful or contraindicated. Concomitant sepsis and furosemide administration may affect successful therapy.

Hanford Patrol Academy demolition sites closure plan

Energy Technology Data Exchange (ETDEWEB)

1993-09-30

The Hanford Site is owned by the U.S. Government and operated by the U.S. Department of Energy, Richland Operations Office. Westinghouse Hanford Company is a major contractor to the U.S. Department of Energy, Richland Operations Office and serves as co-operator of the Hanford Patrol Academy Demolition Sites, the unit addressed in this paper. This document consists of a Hanford Facility Dangerous Waste Part A Permit Application, Form 3 (Revision 4), and a closure plan for the site. An explanation of the Part A Form 3 submitted with this closure plan is provided at the beginning of the Part A section. This Hanford Patrol Academy Demolition Sites Closure Plan submittal contains information current as of December 15, 1994.

Impact of Vial Capping on Residual Seal Force and Container Closure Integrity.

Science.gov (United States)

Mathaes, Roman; Mahler, Hanns-Christian; Roggo, Yves; Ovadia, Robert; Lam, Philippe; Stauch, Oliver; Vogt, Martin; Roehl, Holger; Huwyler, Joerg; Mohl, Silke; Streubel, Alexander

2016-01-01

The vial capping process is a critical unit operation during drug product manufacturing, as it could possibly generate cosmetic defects or even affect container closure integrity. Yet there is significant variability in capping equipment and processes, and their relation to potential defects or container closure integrity has not been thoroughly studied. In this study we applied several methods-residual seal force tester, a self-developed system of a piezo force sensor measurement, and computed tomography-to characterize different container closure system combinations that had been sealed using different capping process parameter settings. Additionally, container closure integrity of these samples was measured using helium leakage (physical container closure integrity) and compared to characterization data. The different capping equipment settings lead to residual seal force values from 7 to 115 N. High residual seal force values were achieved with high capping pre-compression force and a short distance between the capping plate and plunge. The choice of container closure system influenced the obtained residual seal force values. The residual seal force tester and piezoelectric measurements showed similar trends. All vials passed physical container closure integrity testing, and no stopper rupture was seen with any of the settings applied, suggesting that container closure integrity was warranted for the studied container closure system with the chosen capping setting ranges. The vial capping process is a critical unit operation during drug product manufacturing, as it could possibly generate cosmetic defects or even affect container closure integrity. Yet there is significant variability in capping equipment and processes, and their relation to potential defects or container closure integrity has not been thoroughly studied. In this study we applied several methods-residual seal force tester, a self-developed system of a piezo force sensor measurement, and

Military Base Closures: Updated Status of Prior Base Realignments and Closures

Science.gov (United States)

As the Department of Defense (DOD) prepares for the 2005 base realignment and closure (BRAC) round, questions continue to be raised about the transfer and environmental cleanup of unneeded property arising from the prior four BRAC rounds and their impact on cost and savings and on local economies.

Transuranic Storage Area (TSA)-2 container storage unit RCRA closure plan

International Nuclear Information System (INIS)

Lodman, D.W.; Spry, M.J.; Nolte, E.P.; Barry, G.A.

1992-11-01

This document describes the proposed plans for closure of the Transuranic Storage Area (TSA)-2 container storage unit at the Idaho National Engineering Laboratory in accordance with the Resource Conservation and Recovery Act closure requirements. The location, size, capacity, history, and current status of the unit are described. Future plans for the unit include incorporating the earthen-covered portion of the TSA-2 pad into a TSA retrieval enclosure along with the TSA-1 and TSAR pads, and closure of the portion of the TSA-2 pad under the Air Support Weather Shield (ASWS-2). This plan addresses closure of the ASWS-2 by decontaminating structures and equipment that may have contacted the waste. Sufficient sampling and documentation of all closure activities will be performed to demonstrate clean closure. A tentative schedule is provided in the form of a milestone chart

Phenomenology of convection-parameterization closure

Directory of Open Access Journals (Sweden)

J.-I. Yano

2013-04-01

Full Text Available Closure is a problem of defining the convective intensity in a given parameterization. In spite of many years of efforts and progress, it is still considered an overall unresolved problem. The present article reviews this problem from phenomenological perspectives. The physical variables that may contribute in defining the convective intensity are listed, and their statistical significances identified by observational data analyses are reviewed. A possibility is discussed for identifying a correct closure hypothesis by performing a linear stability analysis of tropical convectively coupled waves with various different closure hypotheses. Various individual theoretical issues are considered from various different perspectives. The review also emphasizes that the dominant physical factors controlling convection differ between the tropics and extra-tropics, as well as between oceanic and land areas. Both observational as well as theoretical analyses, often focused on the tropics, do not necessarily lead to conclusions consistent with our operational experiences focused on midlatitudes. Though we emphasize the importance of the interplays between these observational, theoretical and operational perspectives, we also face challenges for establishing a solid research framework that is universally applicable. An energy cycle framework is suggested as such a candidate.

Crack closure and sequential effects in fatigue: A literature survey

Science.gov (United States)

Holmgren, M.

A literature survey of the phenomenon of crack closure is reported here. The state of the art is reviewed and several empirical formulas for determining the crack closure are compared with each other. Their properties, advantages and disadvantages are briefly discussed. Experimental techniques for determining the crack closure stress are presented and experimental data from the literature are reported.

303-K Storage Facility: Report on FY98 closure activities

International Nuclear Information System (INIS)

Adler, J.G.

1998-01-01

This report summarizes and evaluates the decontamination activities, sampling activities, and sample analysis performed in support of the closure of the 303-K Storage Facility. The evaluation is based on the validated data included in the data validation package (98-EAP-346) for the 303-K Storage Facility. The results of this evaluation will be used for assessing contamination for the purpose of closing the 303-K Storage Facility as described in the 303-K Storage Facility Closure Plan, DOE/RL-90-04. The closure strategy for the 303-K Storage Facility is to decontaminate the interior of the north half of the 303-K Building to remove known or suspected dangerous waste contamination, to sample the interior concrete and exterior soils for the constituents of concern, and then to perform data analysis, with an evaluation to determine if the closure activities and data meet the closure criteria. The closure criteria for the 303-K Storage Facility is that the concentrations of constituents of concern are not present above the cleanup levels. Based on the evaluation of the decontamination activities, sampling activities, and sample data, determination has been made that the soils at the 303-K Storage Facility meet the cleanup performance standards (WMH 1997) and can be clean closed. The evaluation determined that the 303-K Building cannot be clean closed without additional closure activities. An additional evaluation will be needed to determine the specific activities required to clean close the 303-K Storage Facility. The radiological contamination at the 303-K Storage Facility is not addressed by the closure strategy

Barriers and post-closure monitoring (AL121125)

International Nuclear Information System (INIS)

Bostick, K.V.; Janecky, D.

1995-01-01

This project focuses on the rapid implementation of near-surface barriers, biotreatment, and post-closure monitoring technology. It uses water-permeable and biologic barriers that chemically capture and/or degrade contaminants without significantly altering the natural water flow regime. Barrier approaches are being tested for two different applications. The first is the use of barriers for confinement of chemical contaminants for in-trench treatments with leach systems or an in-place bioreactor. The second is an enhancement of the current practice of emplacing grout or clay slurry walls into direct horizontal surface and subsurface water flows around a contaminated area by integrating permeable reactive barriers and petroleum reservoir gel/foam/polymer technology

Percutaneous Patent Ductus Arteriosus (PDA) Closure in Very Preterm Infants: Feasibility and Complications.

Science.gov (United States)

Backes, Carl H; Cheatham, Sharon L; Deyo, Grace M; Leopold, Scott; Ball, Molly K; Smith, Charles V; Garg, Vidu; Holzer, Ralf J; Cheatham, John P; Berman, Darren P

2016-02-12

Percutaneous closure of patent ductus arteriosus (PDA) in term neonates is established, but data regarding outcomes in infants born very preterm (closure at weights closure. Twenty-five percent (13/52) of infants were closure. Compared to precatheterization trends, percutaneous PDA closure resulted in improved respiratory status, including less exposure to mechanical ventilation (mixed effects logistic model, Pclosure at weights closure versus alternative (surgical ligation) management strategies. © 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

Angle closure glaucoma in congenital ectropion uvea.

Science.gov (United States)

Wang, Grace M; Thuente, Daniel; Bohnsack, Brenda L

2018-06-01

Congenital ectropion uvea is a rare anomaly, which is associated with open, but dysplastic iridocorneal angles that cause childhood glaucoma. Herein, we present 3 cases of angle-closure glaucoma in children with congenital ectropion uvea. Three children were initially diagnosed with unilateral glaucoma secondary to congenital ectropion uvea at 7, 8 and 13 years of age. The three cases showed 360° of ectropion uvea and iris stromal atrophy in the affected eye. In one case, we have photographic documentation of progression to complete angle closure, which necessitated placement of a glaucoma drainage device 3 years after combined trabeculotomy and trabeculectomy. The 2 other cases, which presented as complete angle closure, also underwent glaucoma drainage device implantation. All three cases had early glaucoma drainage device encapsulation (within 4 months) and required additional surgery (cycloablation or trabeculectomy). Congenital ectropion uvea can be associated with angle-closure glaucoma, and placement of glaucoma drainage devices in all 3 of our cases showed early failure due to plate encapsulation. Glaucoma in congenital ectropion uvea requires attention to angle configuration and often requires multiple surgeries to obtain intraocular pressure control.

Development of an atmospheric diffusion numerical model for a nuclear facility. Numerical calculation method incorporating building effects

International Nuclear Information System (INIS)

Sada, Koichi; Michioka, Takenobu; Ichikawa, Yoichi

2002-01-01

Because effluent gas is sometimes released from low positions, viz., near the ground surface and around buildings, the effects caused by buildings within the site area are not negligible for gas diffusion predictions. For these reasons, the effects caused by buildings for gas diffusion are considered under the terrain following calculation coordinate system in this report. Numerical calculation meshes on the ground surface are treated as the building with the adaptation of wall function techniques of turbulent quantities in the flow calculations using a turbulence closure model. The reflection conditions of released particles on building surfaces are taken into consideration in the diffusion calculation using the Lagrangian particle model. Obtained flow and diffusion calculation results are compared with those of wind tunnel experiments around the building. It was apparent that features observed in a wind tunnel, viz., the formation of cavity regions behind the building and the gas diffusion to the ground surface behind the building, are also obtained by numerical calculation. (author)

Numerical analysis

CERN Document Server

Scott, L Ridgway

2011-01-01

Computational science is fundamentally changing how technological questions are addressed. The design of aircraft, automobiles, and even racing sailboats is now done by computational simulation. The mathematical foundation of this new approach is numerical analysis, which studies algorithms for computing expressions defined with real numbers. Emphasizing the theory behind the computation, this book provides a rigorous and self-contained introduction to numerical analysis and presents the advanced mathematics that underpin industrial software, including complete details that are missing from most textbooks. Using an inquiry-based learning approach, Numerical Analysis is written in a narrative style, provides historical background, and includes many of the proofs and technical details in exercises. Students will be able to go beyond an elementary understanding of numerical simulation and develop deep insights into the foundations of the subject. They will no longer have to accept the mathematical gaps that ex...

Mixed Waste Management Facility closure at the Savannah River Site

International Nuclear Information System (INIS)

Bittner, M.F.

1991-08-01

The Mixed Waste Management Facility of the Savannah River Plant received hazardous and solid low level radioactive wastes from 1972 until 1986. Because this facility did not have a permit to receive hazardous wastes, a Resource Conservation and Recovery Act closure was performed between 1987 and 1990. This closure consisted of dynamic compaction of the waste trenches and placement of a 3-foot clay cap, a 2-foot soil cover, and a vegetative layer. Operations of the waste disposal facility, tests performed to complete the closure design, and the construction of the closure cap are discussed herein

Comparison of slitlamp optical coherence tomography and scanning peripheral anterior chamber depth analyzer to evaluate angle closure in Asian eyes.

Science.gov (United States)

Wong, Hon-Tym; Chua, Jocelyn L L; Sakata, Lisandro M; Wong, Melissa H Y; Aung, Han T; Aung, Tin

2009-05-01

To evaluate the effectiveness of slitlamp optical coherence tomography (SL-OCT) and Scanning Peripheral Anterior Chamber depth analyzer (SPAC) in detecting angle closure, using gonioscopy as the reference standard. A total of 153 subjects underwent gonioscopy, SL-OCT, and SPAC. The anterior chamber angle (ACA) was classified as closed on gonioscopy if the posterior trabecular meshwork could not be seen; with SL-OCT, closure was determined by contact between the iris and angle wall anterior to the scleral spur; and with SPAC by a numerical grade of 5 or fewer and/or a categorical grade of suspect or potential. A closed ACA was identified in 51 eyes with gonioscopy, 86 eyes with SL-OCT, and 61 eyes with SPAC (gonioscopy vs SL-OCT, P gonioscopy vs SPAC, P = .10; SL-OCT vs SPAC, P gonioscopy, SL-OCT detected a closed ACA in 43, whereas SPAC identified 41 (P = .79). An open angle in all 4 quadrants was observed in 102 eyes with gonioscopy, but SL-OCT and SPAC identified 43 and 20 of these eyes, respectively, as having angle closure. The overall sensitivity and specificity for SL-OCT were 84% and 58% vs 80% and 80% for SPAC. Using gonioscopy as the reference, SL-OCT and SPAC showed good sensitivity for detecting eyes at risk of angle closure.

Cystic Duct Closure by Sealing With Bipolar Electrocoagulation

Science.gov (United States)

Damgaard, B.; Jorgensen, L. N.; Larsen, S. S.; Kristiansen, V. B.

2010-01-01

Background: Cystic duct leakage after cholecystectomy is not uncommon and is a potentially serious complication. The aim of this study was to assess a bipolar sealing system (LigaSure®) for closure of the cystic duct. Methods: The records from consecutive laparoscopic cholecystectomies performed in 2 hospitals with closure of the cystic duct with LigaSure after informed consent were recorded and complications and morbidity registered. The records were compared with those of patients undergoing laparoscopic cholecystectomy with closure of the cystic duct with clips during the same period. Results: During the study period, 218 laparoscopic cholecystectomies were performed; 102 of these were performed with the LigaSure. One patient was excluded due to violation of the protocol. We experienced no cases of cystic duct leakage, but in one patient, bile leakage from the gallbladder bed was observed probably due to a small aberrant duct. Conclusion: The LigaSure system was safe and effective for closure and division of the cystic duct in laparoscopic cholecystectomy. PMID:20412641

LLNL/YMP Waste Container Fabrication and Closure Project

International Nuclear Information System (INIS)

1990-10-01

The Department of Energy's Office of Civilian Radioactive Waste Management (OCRWM) Program is studying Yucca Mountain, Nevada as a suitable site for the first US high-level nuclear waste repository. Lawrence Livermore National Laboratory (LLNL) has the responsibility for designing and developing the waste package for the permanent storage of high-level nuclear waste. This report is a summary of the technical activities for the LLNL/YMP Nuclear Waste Disposal Container Fabrication and Closure Development Project. Candidate welding closure processes were identified in the Phase 1 report. This report discusses Phase 2. Phase 2 of this effort involved laboratory studies to determine the optimum fabrication and closure processes. Because of budget limitations, LLNL narrowed the materials for evaluation in Phase 2 from the original six to four: Alloy 825, CDA 715, CDA 102 (or CDA 122) and CDA 952. Phase 2 studies focused on evaluation of candidate material in conjunction with fabrication and closure processes

Influence of Closure & Non-Closure of the Visceral and Parietal Peritoneum on Post Cesarean Morbidity

Directory of Open Access Journals (Sweden)

Z Tabasi

2012-05-01

Full Text Available

Background and Objectives: One of the most important issues in promoting mother and child health is reducing the morbidity rate after cesarean section. The aim of this study was to investigate the influence of closure and non-closure of the visceral and parietal peritoneum on post cesarean morbidity in women attending Shabihkhani Maternity Hospital in Kashan, Iran.

Methods: This study was conducted with a single blind randomized clinical trial method on 100 parturient women that underwent emergency or elective cesarean section. Patients with previous cesarean section and or abdominal surgery, diseases such as hypertension, diabetes mellitus and premature rupture of membrane and pre operative bleeding, were excluded from this study. Then, the participants were randomly divided into two groups: in one group both peritoneal layers were closed while in the other group, they were not closed. Post operative morbidity including fever, bleeding, post operative pain, analgesic consumption and time of operation were assessed. Data were analyzed with t-tests, and χ2 and a P<0.05 were considered significant.

Results: In this study, there were no significant differences between the two groups with respect to age, gestational age, the reason for caesarean section and gravidity, nor were there any differences with respect to the incidence of fever or bleeding and was similar between the two groups, but there was a significant difference between the two groups regarding to feeling of severe pain (P=0.0003, analgesic consumption (P=0.0003 and time of operation (P=0.004. In the non-closure group, dose of analgesic drugs, pain severity and time of operation were less than those of the other group.