Characterization of Particulate Matter Accumulated on Ramalina farinacea in the Seattle Area Using Semi-Automated Electron Microscopy

Semi-automated scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS) can be used to determine the size and composition of filtered particulate matter (PM). This information is valuable for determining the identity and contribution of overlapping air emissions. One limitation of this method is the cost of filtering PM at enough locations to give meaningful spatial data. To address this limitation, I developed an exploratory method to collect PM using Ramalina farinacea for semi-automated SEM analysis as a component of lichen biomonitoring studies. I applied this method as a proof of concept in the Seattle area to better understand trends in regional urban dust. To do this, bags of lichen were transplanted to 9 locations in the Duwamish Valley and adjacent uplands for 3 months between September and December, 2017. Some of these locations were arranged close to major industrial sources of airborne metals, which we hypothesized would contribute to the PM observed on the lichens alongside the regional background signature of particulate emissions. Upon collection, PM deposition on the lichen was characterized using SEM with EDS. A total of 18,581 particles were identified and analyzed using the PACLA for Oxford two-stage classifier. My findings suggest that R. farinacea are an effective tool for collecting PM and show the greatest proportion of anthropogenic-specific particles on lichens adjacent to Interstate 5. Furthermore, the spatial trends of PM between locations suggest that fugitive dust controls such as green walls and green spaces may be more effective than point source controls at further reducing exposure to harmful dust in the Seattle area

Structural performance of a prefabricated concrete beam with longitudinal cavities

Master's thesis in Structural engineeringPrecast concrete elements are getting more and more popular in the construction industry. The precast elements are casted into many different shapes and sizes, which includes walls, beams, columns, slabs and more. There are many advantages of using them, although there are also many limitations. Moreover, concrete elements pass different stages such as casting, storing, transporting and disassembling. Especially the last two stages, brings several limitations regarding size and especially weight to the picture. A specific project turned out to have some problems regarding the weight of a large continuous beam with cross-shaped (special DLB) cross section, carrying hollow decks on both corbels, created the motivation for the topic of this thesis. Many different ideas on how to reduce the weight of the beam were mentioned. Use of lightweight concrete, use pf pre-stressing beams, hollow sections, geometrical changes and many others were proposed. Inspiration from hollow decks and IB-beams created the final idea of using longitudinal cavities as a measure. Originally, the beam was designed using a Gerber system, a system which allows for splitting a continuous beam in parts. It also had transverse cavities. However, for simplicity, the original beam has been re-designed for a case without either Gerber or transverse cavities. The beams have been designed using rules given in Eurocode 2 [1] and design guidelines given in the concrete element book [2] [3]. Also, a publication [4] regarding where the Euler-Bernoulli beam theory is valid for concrete structures has been used in the design phase. Practical design with regards to production has had a very high focus. Preliminary control and calculations for design were mostly done using simple software [5] for design of concrete structures directly towards Eurocode 2 with Norwegian annex. Through discussion and trial & error, a design with a cavity below the neutral axis were proposed, which then maintained almost all its theoretical bending moment capacity (cracked section assumed). As the initial beam were assumed to be sufficiently constrained in the lateral direction, the shear capacity then turned out to be the main issue for design. Reduction in shear capacity introduced further limits to where the design may be used. The initial beam cross section consists of a rectangular beam 520mm*980mm with rectangular corbels 150mm*250mm on each side starting at 350mm above the most bottom part. Space for two layers of ø32 in both top and bottom, shear rebar ø16, and corbel rebar both in the transverse ø12 and longitudinal direction. For the modified cross section, the bottom part of corbels was angled at 45 degrees. A cylindrical cavity ø300 were added and corbel rebar adjusted accordingly. Longitudinal and shear rebar were unaffected. The cavities were added at a distance equivalent to effective depth, “d”, of the cross section from the face of each support, unless the shear capacity of the cross section were violated, in which it was moved accordingly. In sum, these modifications reduced the total weight of the continuous beam by ~9%. To study the structural behavior of the proposed beam, numerical analysis was then carried out using a non-linear finite element software (i.e. ATENA [6]) specifically aimed at concrete structures. Two models were produced for comparison, and two extra for control of shear rebar and mesh size. All the numerical results produced a way too high crack width, though all models mostly passed criteria for deflection, crushing of concrete and yielding of rebar. Comparatively, the higher range of values in the modified beam had mostly ~5-10% higher values for crack width, deflection and compressive stress in concrete. In sum, this design approach seems to be a good measure, though the economical and other aspects have not been analyzed in detail. Further studies must be performed for a proper conclusion

A search for the Higgs boson decaying to e+e− using data from the ATLAS detector

Aim: The aim of this thesis is to examine the decay of the Higgs boson to an electron-positron pair, H → e+ e− using the invariant mass of the leading and sub-leading electrons. Method: An invariant mass reconstruction model, with two different types of cuts, was developed by looking at a Z → e+ e− Monte Carlo sample and then real data. The model was then been run on real data from the LHC. Findings: By running the model against real data, it is found that the model correctly identifies the presence of Z bosons and also confirms that Higgs bosons are not present in the samples that the model is investigating. This model got limits for the effective cross sections of the H → e+ e− decay. For the 2018 sample with a pT > 20 GeV cut the effective cross section limit was found to be σ_eff < 99.04 fb and for the 2016 sample with Loose electrons the effective cross section limit was found to be σ_eff < 24.23 fb.Masteroppgave i fysikkPHYS399MAMN-PHY

Effects of land cover on ecosystem services in Tanzania: A spatial assessment of soil organic carbon

AbstractThe multiple ecosystem services provided by healthy soil are well known and include soil carbon sequestration to mitigate climate change, a medium for plant and agricultural production and regulating the hydrologic cycle. Despite the wide recognition of the importance of these services, drivers of soil organic carbon (SOC) dynamics across various land uses in East Africa are poorly understood. The objectives of this study were threefold: to quantify SOC stocks across Tanzania; assess the effect of land cover and erosion on SOC; and investigate the relationship between inherent and dynamic soil properties under diverse land uses. The Land Degradation Surveillance Framework (LDSF) was used to assess the variability of ecological metrics at different spatial scales. SOC was quantified within and between different land cover types (forest, woodland, shrubland, grassland and cropland) in Tanzania. A total of 2052 soil samples from 1082–1000m2 plots were collected from seven 100-km2 sentinel sites in 2010. Composite soil samples were collected at each plot from two depths (0–20 and 20–50cm) and cumulative soil mass samples were collected to 100cm. Soil samples were analyzed using a combination of traditional analytical laboratory methods and mid-infrared spectroscopy (MIR). Model performance of MIR spectral predictions for carbon was good, with an R2 of >0.95 and RMSEP of 4.3gkg−1, when using an independent validation datasets. Woodland and cropland were the most frequently occurring vegetation structure types in the sampled sites, with 388 and 246 plots, respectively. Average topsoil OC (and range) was 12.4 (1.5–81.4) gCkg−1 (n=1082) and average subsoil OC (and range) was 7.3 (0.64–53.8) gCkg−1 (n=970) for the seven sites. Forested plots had the highest mean topsoil organic carbon concentrations (17.3gCkg−1) followed by cropland (13.3gCkg−1), for all sites included in the study, but with high levels of variability between sites. Soil mass at 30cm was measured and these data were used to calculate carbon stocks for the different land cover types. An approach based on remote sensing was explored for the mapping of SOC stocks at 30cm for Tanzania using Moderate Resolution Imaging Spectroradiometer (MODIS) imagery from 2012. Results indicate that the use of image reflectance for the mapping of SOC stocks has promising potential, with R2 values ranging from 0.77 to 0.81 and RMSEP values from 0.90 to 1.03kgm−2 for the three validation datasets. There is high utility of these maps for strategic land management interventions that prioritize ecosystem services

Introduction of cognitive support technologies (CST) for job seekers

Research shows that adults with cognitive impairment can benefit from cognitive support technologies (CST), and combined with good coping strategies, these technologies can help facilitate inclusion in the labour market. Experience from our rehabilitation work in Norway shows that introducing CST to persons with Asperger’s syndrome and/or attention-deficit hyperactivity disorder (ADHD) can be challenging. This study describes and discusses factors that can promote or inhibit the introduction of CST in vocational rehabilitation services. These descriptions are based on twelve months of ethnographic fieldwork in two vocational rehabilitation programmes in Norway. We describe how adequate time, mandatory integration of technology in activities, recognition of and faith in the individual's ability to eventually find a job as part of a professional strategy, and the use of the job seekers’ own technologies, are intertwined and interdependent factors that promote the introduction of CST. The inhibiting factors we describe may be related to the diagnosis of the typical challenges faced by adults suffering from ADHD and/or Asperger’s, such as organizational challenges, procrastination or general difficulty in doing things in a new way.publishedVersio

Deep sea divers: A tale about care and camaraderie. Stories of deep sea diving between 1966 and 1980

For å bygge opp og utvikle den norske oljeindustrien gjennom 1970-årene, var Norge helt avhengig av petroleumsdykkere. Dykkerne utførte grensesprengende arbeid på oppdrag for petroleumsindustrien ute i havet og ved bygging av store betonginstallasjoner i norske fjorder. I 1967 slo norske myndigheter fast at dykkevirksomheten skulle foregå under regulerte former og at dykkernes sikkerhet og helbred skulle ivaretas. Myndighetene satte krav om at dykkeoperasjoner skulle godkjennes av myndighetene før de kunne igangsettes. I praksis skjedde ikke dette. Dykkere forteller at alt var tillatt og opp til selskapene. Petroleumsdykkere jobbet på stadig større dybder ut fra industriens behov. Det ble eksperimentert med dykketabeller og gassblandinger ble tilpasset og prøvd ut. Store arbeidsanstrengelser ble utført på lange arbeidsøkter, langt vekk fra myndighetenes kontroll. Ute i havet levde gjerne dykkerne tett på hverandre over lengre perioder og som regel hadde de arbeidskontrakter av kortere varighet. Det var ikke kultur for å si fra om ugreie forhold, noe som ble sett på som svakhet, og veien var kort til å bli avskiltet som dykker. I dette arbeidsmiljøet utviklet det seg et unikt og tett arbeidskollektiv som var preget av kameratskap og omsorg i arbeidssituasjonen. Uten at arbeidskulturen framsto som myk, var det å ta vare på seg selv og arbeidskollegaen helt nødvendig og det beste sikkerhetskortet da myndighetene sviktet med å gi dykkerne et tilstrekkelig arbeidsvern.Norway was completely dependent on deep sea divers to start and develop its oil industry during the 1970s. These divers did groundbreaking work for the oil industry both offshore and by their contribution to build large concrete installations in Norwegian fjords. In 1967, Norwegian authorities concluded that the diving activities should be regulated and that the security and health of the divers should be taken care of. The authorities demanded that diving operations should be approved before employment. This did not happen. Divers say that everything was allowed and that the operators in the North Sea made their own rules. Deep sea divers worked on ever greater depths, all depending on the industry’s needs. Experiments were made with dive tables and gas blends. Large efforts were made during long work hours, far from the eyes of the Norwegian authorities. Offshore, it was not unusual for groups of divers to live together in small living quarters over lengthy periods. Their work contracts were usually short and there was therefore no culture for speaking about unsound conditions. Whistle blowing could be seen as a weakness, and divers who did so, risked being blacklisted from future work. From these conditions, a unique and close work collective developed, with a lot of camaraderie and care between the colleagues, without it being «soft». This type of inclusive collective was the best form of safety insurance for the divers when the authorities failed in giving them sufficient occupational safety and protection.publishedVersio