High Fidelity Deterministic Solution of Neutron Transport Problems in Graphite

The study of thermal radiative transfer in the high energy density regime is important to the National Nuclear Security Administration, and experiments are an important component of such studies. Strong non-linear coupling of radiation hydrodynamics and thermal radiation transport makes it difficult to infer radiation transport uncertainties from experiments. In order to address this problem and have a hierarchical approach to model validation, the Center for Exascale Radiation Transport (CERT), created at Texas A&M University, has designed neutrons-in-graphite experiments as surrogates for thermal radiative transfer in high energy density. There is a strong mathematical analogy between the process of radiative absorption and emission, and the process of neutrons scattering in highly diffusive mediums. This allows the solution for thermal radiation transport benchmark problems to be measured by the neutrons-in-graphite surrogate experiments. The CERT team has designed a series of neutrons-in-graphite experiments to allow investigation of many of the significant transport difficulties regarding thermal radiative transport including: multi-scale modelling in time, space, and angle; highly scalable parallel solution techniques; and refinement in time, space, and angle. The development of computation methods to efficiently and accurately simulate the neutrons-in-graphite surrogate experiments and the predictive science methods to quantify the uncertainty will also be applicable to the analogous thermal radiation transport simulations. This thesis systematically investigates the required spatial, angular, and energy resolution needed to obtain high-fidelity deterministic transport solutions for the neutrons-in-graphite experiments designed as surrogates for thermal radiative transfer. Semi-analytic and stochastic methodologies are considered in order to investigate the deterministic neutron transport discretization error as a function of the spatial, angular, and energy resolution. For the discretization error calculations, a hierarchical approach is taken towards increasingly complex geometries. Infinite graphite medium problems with a uniform source have only energy dependence. The infinite medium problems are used to compute the deterministic multi-group discretization error as a function of the energy resolution. 2D graphite problems with an infinite line source and 3D graphite cube problems with a point source are modelled to analyze spatial and angular discretization error as a function of spatial and angular resolution. An analysis is performed on the angular discretization ray effect errors that are present in deterministic discrete ordinate calculations. This research informs the uncertainty quantification efforts for CERT and points the way to the further development of deterministic calculations

Maintaining Disorder: Some Technical and Aesthetic Issues Involved in the Performance of Ligeti’s E´ tudes for Piano

This article examines some of the particular questions and associated strategies concerning matters of rhythm, perceived metre, notation, accentuation, line, physical approach to the keyboard, pedalling, and more in the performance of Ligeti’s Études for piano. I relate these issues to those encountered in earlier repertoire, including works of Schumann, Liszt, Stravinsky, Prokofiev, Bartók and Blacher, and argue that particular approaches and attitudes to both technical and musical matters in the context of these Études can fundamentally affect the concept of the music. A particular focus is upon issues of continuity and discontinuity, and the ‘situation’ of these works within particular pianistic and other traditions by virtue of the approach taken to performance

Short term prediction of the horizontal wind vector within a wake vortex warning system

A wake vortex warning system (WVWS) has been developed for Frankfurt airport. This airport has two parallel runways which are separated by 518 m, a distance too short to operate them independently because wake vortices may be advected to the adjacent runway. The objective of the WVWS is to enable operation with reduced separation between two aircraft approaching the parallel runways at appropriate wind conditions. The WVWS applies a statistical persistence model to predict the crosswind within a 20 minute period. One of the main problems identified in the old WVWS are discontinuities between successive forecasts. These forecast breakdowns were not acceptable to airtraffic controllers. At least part of the problem was related to the fact that the forecast was solely based on the prediction of crosswind. A new method is developed on the basis of 523 days of sonic anemometer measurements at Frankfurt airport. It is demonstrated that the prediction of the horizontal wind vector avoids these difficulties and significantly improves the system's performance. (orig.)15 refs.Available from TIB Hannover: RR 6341(138) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Cerebral metastasis of cervical uterine cancer: report of three cases Metástases cerebrais de câncer de colo de útero: relato de três casos

Cervical uterine cancer (CUC) spreads locally (pelvis and paraortic lymphnodes) or distantly (lungs, liver and bones). Metastasis to central nervous system (CNS) are rare. There are about 80 cases reported in the literature. Outcome is poor and survival varies from 3 to 6 months. Three cases of CNS metastasis from CUC are reported, one infratentorial and two supratentorials in location. In one patient, the initial manifestation was due to the cerebral lesion, a feature reported for the first time. All cases were treated by surgery, radiotherapy and/or chemotherapy. Clinical findings and treatment options of these rare lesions are reviewed.<br>Tumores do cólo uterino se disseminam por contigüidade ou via hematogênica (pulmão, fígado e ossos). Metástases para sistema nervoso central são incomuns. Apenas cerca de 80 casos são citados na literatura. Manifestações clínicas são devidas à hipertensão intracraniana e a déficits focais. A sobrevida varia de 3 a 6 meses. Três casos são relatados sendo um infratentorial e dois supratentoriais. No primeiro, o diagnóstico da metástase antecedeu o da lesão uterina. No segundo, houve 5 anos sem recidiva após a cirurgia, fato este inédito. O tratamento foi cirurgia, radioterapia e/ou quimioterapia. A discussão enfatiza manejo multidisciplinar destas raras lesões

Interventions that address institutional child maltreatment: an evidence and gap map.

Purpose: This evidence and gap map collates evidence reporting on the effectiveness of interventions aimed to prevent, disclose, respond to, or treat child maltreatment occurring in institutional settings. Methods: A comprehensive and systematic literature search identified primary studies and systematic reviews meeting the review’s eligibility criteria. Literature screening, data extraction and critical appraisals were undertaken independently by multiple reviewers. Data extracted and reported from the included studies included information about the institutional setting, target population, type of maltreatment, intervention type and outcomes. Results: Seventy-three studies were identified, including 11 systematic reviews and 62 primary studies. Overall, the methodological quality of the studies was low to moderate. Most evaluated curriculum-based interventions delivered in educational settings, primarily aimed at preventing sexual abuse. Fewer studies examined other institutional settings or intervention types. Conclusions: This review highlights a need for high-quality studies evaluating a more diverse range of interventions across more varied institutional contexts