Design, Construction and Characterization of a Portable Fast-Neutron Detector

At European Spallation Source ERIC, 2 GeV proton bunches will be accelerated towards a tungsten target where spallation will occur, producing a wide neutron energy spectrum. Despite the shielding and moderators in place to stop and/or reduce their energy, a significant portion of the most energetic neutrons, called prompt neutrons, might still reach the sample position of a neutron-scattering instrument. It has been previously shown that these prompt neutrons contribute to a degradation of the signal-to-noise ratio of the detectors. Clearly, a tool for identifying sources of fast-neutron background would be very valuable. The design goals of the envisioned Portable Fast-Neutron Diagnostic Detector include portability, durability, fast response and the ability for performing self-triggering time-of-flight measurements complete with tracking to localize fast-neutron sources. Within the context of this thesis, the detector system was conceptualized, designed and a prototype assembled. Testing was carried out with a plutonium/beryllium source and a industry-standard liquid scintillator detector to define a tagged fast-neutron beam (2.8-6.3 MeV). It was shown that the neutron response is energy dependent and improves at lower energies. Fast-neutron tracking capabilities of the detector were demonstrated.Spallations anläggningar är ämnade för produktion och forskning med fria neutroner. Ett problem uppstår för dessa anläggningar efter att högenergetiska neutroner skapas via en så kallad spallation. Högenergetiska neutroner är problematiska att hålla udner kontroll. På grund av deras höga energi kan dessa neutronerna ``rymma'' och orsaka kärnreaktioner som bidrar till en försvagad signal-upplösningen hos forsknings-instrumenten på dessa anläggningarna. Detta projekt behandlar utvecklingen av ett diagnos instrument som kan titta på just dessa högenergetiska neutroner. Instrumentet kan sedan användas av spallations anläggningarna för att kartlägga sina snabba neutroner som rymt

Grid-based CFD optimization

Chapman, N. (2010). Grid-based CFD optimization. http://hdl.handle.net/10251/9128.Archivo delegad

Neutron-Induced Scintillation in Organics

Neutrons are widely used as probes of matter to study materials in a broad range of fields from physics, chemistry and medicine to material sciences. Any application utilizing neutrons needs to employ a well-understood and optimized neutron-detector system. This thesis is centered on fundamental aspects of neutron-detector development, including the establishment of the Source Testing Facility at Lund University, experimental methods for the in-depth characterization of scintillator-based neutron detectors and analytical and computational methods for the precise interpretation of results. It focuses on the response of liquid organic scintillators to fast-neutron and gamma-ray irradiations, specifically for NE 213A, EJ 305, EJ 331 and EJ 321P. A simulation-based method for detector calibration was developed which allowed for the use of polyenergetic gamma-ray sources in this low energy-resolution environment. With an actinide/beryllium neutron source and a time-of-flight setup, beams of energy-tagged neutrons were used to study the energy-dependent behaviour of the intrinsic pulse-shape of NE 213A and EJ 305 scintillators. The results demonstrated the advantages of the neutron-tagging method and how the combination of neutron tagging and pulse-shape discrimination can give deeper insight into backgrounds resulting from inelastic neutron scattering. A comprehensive characterization of the neutron scintillation-light yield for NE 213A, EJ 305, EJ 331 and EJ 321P was also performed. It employed the simulation-based calibrations to confirm existing light-yield parametrizations for NE 213A and EJ 305, and resulted in light-yield parametrizations for EJ 331 and EJ 321P extracted for the first time from data. In addition to the development of a simulation-based framework for the study of neutron-induced scintillation in organic scintillators, the methods and results presented in this thesis lay the foundation for future source-based neutron-tagging efforts and scintillator-detector research and development

Nyhedernes musik

På trods af, at funktionel musik spiller en vigtig rolle i medierne, er musik- kens ’strategiske’ funktioner ikke specielt vel belyst i hverken medieforsk- ningen eller markedsforskningen. Artiklen næranalyserer 23 sekunders underlægningsmusik til TV2 Nyhedernes introduktion en tilfældig aften og belyser i samklang med Jørgen Stigels artikel, hvorledes nyhedernes musik tager karakter af egenreklame: Musikken er ’lytfang’ og auditivt klister – en dynamisk instans, som skaber stemningsmæssig sammen- hæng i nyhedernes forskræp. Musikken må være distinktiv, skabe op- mærksomhed og gøre nyhederne identificerbare både i forhold til de om- givende reklamer på kanalen, andre tv-kanalers nyhedsudsendelser og hverdagslige gøremål i brugssituationen

Authentic Assessment For Yuuyaraq Middle School Students Based On The Yuuyaraq Curriculum

Thesis (M.A.) University of Alaska Fairbanks, 2010This study examines how the Yuuyaraq curriculum is being applied in the context of a middle school classroom in a small Yup'ik village in Alaska, specifically focusing on how to better assess the outcomes of the curriculum. In the early 1980s, the Yuuyaraq curriculum (YC) was revised to include the seasonal activities of the region, but lacked alignment with the assessments. By using the Participatory Action Research methodology, the researcher identified a problem, observed the situation, analyzed and interpreted the data, and developed an action plan. Data revealed that authentic assessments used in the Yuuyaraq curriculum can be assess Indigenous knowledge, how teachers' indigenous knowledge contributed to a classroom, and how rubrics are in need in a classroom to monitor student progress. The conclusions include various forms of authentic assessments used in the YC, how teacher's knowledge and practice contributed to a classroom that focused on her students' culture and identity and engaged them in a culturally relevant curriculum through the frameworks of sociocultural theory and Indigenous knowledge systems

Degrees of Damage: Quantifying male vs. female exercise-induced muscle damage through magnetization transfer ratios

No direct, quantitative, and non-invasive markers presently exist to assess exercise-induced muscle damage (EIMD). However, magnetization transfer ratios (MTR), an emerging measurement quantified via magnetic resonance imagery, provide more direct indication of muscle integrity following EIMD. This study compares and correlates the temporal pattern of the MTR to alternative indirect markers of EIMD in male vs. female populations, and subsequently establishes whether there are sex differences in biochemical activity during recovery. The antioxidant properties of estrogen hypothetically minimize muscle trauma, maintain membrane stability, and limit swelling resulting in heightened tissue integrity and resilience to EIMD. Six males and three females completed a standardized eccentric bicep preacher curl protocol of 10 sets of 10 reps (1 minute rest between sets) with 110% of the subjects MVC for a 3-second eccentric component. Joint angle, rate of perceived pain (RPP), maximum voluntary contraction (MVC), muscle cross-sectional area (CSA), transverse relaxation times (T2), and MTR were established at baseline prior to testing, and again at 0hr., 48hr., and 72hr. post EIMD. While joint angle and RPP revealed no significant changes, MVC saw significant decreases in men but not women (males: 84.16lbs ± 24.84lbs to 44.67lbs ± 16.58lbs; females: 55.15lbs ± 8.75lbs to 30.86lbs ± 5.24lbs). Mean male and female CSA increased without significance; however, significant differences were observed between the sexes at baseline and 48hr. Mean T2 relaxation times of the brachialis, medial, and lateral head of the bicep similarly experienced no significant increases within or between sexes (P\u3e0.05). MTR additionally saw no statistical significance within or between males and females. In a recreationally-active population, our investigation concluded that estrogen has no significant effect on the maintenance of MVC post eccentric exercise, DOMs as determined by RPP, maintenance of joint angle, suppression of swelling as evaluated by CSA, or a decrease in changes in MTR or T2 times. While the study revealed little significance between participant groups, in the context of elite athletes and senescing populations, a minor increase in performance, even of only a few percent, could prove valuable

A new species of Systropha from Thailand (Hymenoptera: Halictidae: Rophitinae)

Systropha sirikitae de Silva & Packer, new species, from Thailand is described and illustrated.  It is known only from the male.  Patiny & Michez’s (2006) key to males of Systropha is modified to permit its identification.  It would seem to be the second known species of the subgenus Systrophidia Cockerell

Output growth differentials across the euro area countries - some stylised facts

The aim of this study is to investigate the extent to which the dispersion of real GDP growth rates has changed over the past few years and whether the synchronisation of business cycles has increased among the euro area countries. The study is divided into two main parts. The f irst focuses on the dispersion of real GDP growth rates across the euro area countries, while the second studies the synchronisation of business cycles within the euro area. The study shows first that dispersion of real GDP growth rates across the euro area countries in both unweighted and weighted terms has no apparent upward or downward trend during the period 1970-2004 as a whole. Second, since the beginning of the 1990s, the dispersion of real GDP growth rates across the euro area countries has largely reflected lasting trend growth differences, and less so cyclical differences, with some countries persistently exhibiting output growth either above or below the euro area average. Among other things, this might be due to different trends in demographics, as well as to differences in structural reforms undertaken in the past. Thirdly, the degree of synchronisation of business cycles across the euro area countries seems to have increased since the beginning of the 1990s. This f inding holds for various measures of synchronisation applied to overall activity and to the cyclical component, for annual and quarterly data, as well as for various country groupings. In particular, the degree of correlation currently appears to be at a historical high. In addition to these main findings, certain other stylised facts on dispersion and synchronisation are presented. JEL Classification: C10; E32; O40.Dispersion of GDP growth across the euro area countries; trend and cycle; synchronisation of business cycles within the euro area.

To aggregate or not to aggregate? Euro area inflation forecasting

In this paper we investigate whether the forecast of the HICP components (indirect approach) improves upon the forecast of overall HICP (direct approach) and whether the aggregation of country forecasts improves upon the forecast of the euro-area as a whole, considering the four largest euro area countries. The direct approach provides clearly better results than the indirect approach for 12 and 18 steps ahead for the overall HICP, while for shorter horizons the results are mixed. For the euro area HICP excluding unprocessed food and energy(HICPX), the indirect forecast outperforms the direct whereas the differences are only marginal for the countries. The aggregation of country forecasts does not seem to improve upon the forecast of the euro area HICP and HICPX. This result has however to be taken with caution as differences appear to be rather small and due to the limited country coverage. JEL Classification: C11, C32, C53, E31, E37Bayesian VARs, Forecasting short-term inflation, HICP sub-components/aggregation, Model Selection

Antagonistic effect of chitin-degrading microfungi on thick-shelled pig helminth eggs

The rising demand for pigs produced in organic farming systems, which require access to outdoor areas and associated increased risk of gastrointestinal nematode infections, is creating growing interest in alternative control strategies. Also development of anthelminthic resistance due to extensive use of anthelmintics is a concern in intensive pig production. Use of chitin-degrading microfungi is one of the options. Extensive research has been conducted on biological control of plant pathogenic nematodes using such fungi, and some fungal species are commercially available for plant protection. In contrast, there are only limited laboratory studies conducted on eggs from nematodes which are animal parasites. The aim of present study is to investigate the antagonistic effect of chitin-degrading microfungi on thick-shelled pig helminth eggs (i.e. Ascaris suum and Trichuris suis) both in the laboratory as well as in the field. We have performed a pilot study of the ovicidal effect of Paecilomyces lilacinus alone and in combination with chitin supplement on A. suum eggs over 4 weeks in 2% water agar. Within 1 week more than 90% of the eggs were hatched in both cases within the Petri dish as compared to controls, indicating that the fungus is capable of degrading the chitin wall so the larvae are becoming free. Soon we will proceed for full-fledged study with 2 fungal species (P. lilacinus and Pochonia chlamydosporia) which were proven to have ovicidal activity against nematode eggs. This will be done in the laboratory using soil samples amended with A. suum eggs, under semi-natural (pasture plot) conditions and finally on heavily contaminated pastures