870 resultados para physical and chromatographic characterizations


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Population growth, urban development, and increased commercial and industrial activity in the south-central Puget Lowlands of Washington State has led to an increased demand for groundwater. The Vashon till is a glacially consolidated, low-permeability unit comprising unstratified clay, silt, cobbles and boulders with ubiquitous coarse-grained lenses and is an extensive surficial unit throughout the south-central Puget Lowland. Thus, understanding the physical and hydrological characteristics – specifically, the hydraulic conductivity – of this unit is a necessary component of a groundwater model. This study provides (1) a record of the physical characteristics of Vashon till deposits within the study area; and (2) an estimate of the highest, lowest, and average value of saturated hydraulic conductivity based on the grain-size distribution of Vashon till samples collected from six field sites in the Puyallup River Watershed. Analysis shows that the average moisture content ranges between about 1 and 6%, average dry bulk density is about 2.20 g/cm3, and average porosity is about 17%. Grain-size distributions show that half of the samples analyzed are well graded, while the other half is poorly graded. Grain-size distributions also show an average d10 value of about 0.20 mm, and average ff values ≤ 16%, which are key values in estimating the saturated hydraulic conductivity of over-consolidated glacial deposits. Based on these observed values, the estimates of hydraulic conductivity range from a minimum of 0.02 m/d to a maximum of 1.38 m/d in within the general Vashon till.

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Thesis (Ph.D.)--University of Washington, 2016-06

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Research has found evidence of a link between being overweight or obese and bullying/peer victimisation, and also between obesity and adjustment problems such as low self-esteem and body dissatisfaction. Studies have also found that adjustment problems can put children at an increased risk of being bullied over time. However, to date the factors that place overweight or obese children at risk of being bullied have been poorly elucidated. Self-report data were collected from a sample of 11-14 year olds (N=376) about their weight status, about their experiences of three different types of bullying (Verbal, Physical and Social), their global self-worth, self-esteem for physical appearance, and body dissatisfaction. Overweight or obese children reported experiencing significantly more verbal and physical (but not social) bullying than their non-overweight peers. Global self-worth, self-esteem for physical appearance and body dissatisfaction each fully mediated the paths between weight status and being a victim of bullying.

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Light curable dimethacrylate resin composites undergo free radical photopolymerisation in response to blue light (wavelength 450-500 nm) and may offer superior handling and setting characteristics for novel hard tissue repair materials. The current investigation aims to determine the optimum formulation of bisphenol-A glycidyl methacrylate and triethyleneglycoldimethacrylate (bisGMA/TEGDMA) or urethane dimethacrylate (UDMA)/TEGDMA resin mixtures and the effect of Bioglass incorporation on the rate of polymerisation (RP), degree of conversion (DC) and flexural strength (FS) of light-curable filled resin composites (FRCs). Experimental photoactive resins containing a range of bisGMA, UDMA and TEGDMA ratios and/or filled with non-silanised irregular or spherical 45S5-Bioglass (50 μm; 5-40 wt%) and/or silanised silicate glass filler particulates (0.7 μm; 50-70 wt%) were tested. RP and DC were analysed in real-time using nearinfrared spectroscopy. FS of resins and FRCs were determined using three-point flexural strength tests. UDMA/TEGDMA resins exhibited increased DC compared with bisGMA/TEGDMA resins (p<0.05). The addition of spherical particles of Bioglass had a detrimental effect on the FS (p>0.05), whereas they increased DC of UDMA/TEGDMA resins (p<0.05). Addition of irregular shaped Bioglass particles increased the FS of UDMA/TEGDMA resins up to 20 wt% Bioglass (p<0.05). The flexibility and strength conferred by the urethane group in UDMA may result in enhanced physical and mechanical properties compared with conventional resins containing bulky (bisGMA) molecules. Addition of 45S5-Bioglass with specific filler content, size and morphology resulted in enhanced mechanical and physical properties of UDMA/TEGDMA composites. © (2014) Trans Tech Publications, Switzerland.

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Freshwater wetland soils of the Everglades were studied in order to assess present environmental conditions and paleo-environmental changes using organic geochemistry techniques. Organic matter in dominant vegetation, peat and marl soils was characterized by geochemical means. Samples were selected along nutrient and hydrology gradients with the objective to determine the historical sources of organic matter as well as the extent of its preservation. Effective molecular proxies were developed to differentiate the relative input of organic matter from different biological sources to wetland soils. Thus historical vegetation shifts and hydroperiods were reconstructed using those proxies. The data show good correlations with historical water management practices starting at the turn of the century and during the mid 1900's. Overall, significant shortening of hydroperiods during this period was observed. The soil organic matter (SOM) preservation was assessed through elemental analysis and molecular characterizations of bulk 13C stable isotopes, solid state 13C NMR spectroscopy, UV-Vis spectroscopy, and tetramethyl ammonium hydroxide (TMAH) thermochemolysis-GC/MS. The relationship of the environmental conditions and degradation status of the soil organic matter (SOM) among the sites suggested that both high nutrient levels and long hydroperiod favor organic matter degradation in the soils. This is probably the result of an increase in the microbial activity in the soils which have higher nutrient levels, while longer hydroperiods may enhance physical/chemical degradation processes. The most significant transformations of biomass litter in this environment are controlled by very early physical/chemical processes and once the OM is incorporated into surface soils, the diagenetic change, even over extended periods of time is comparatively minimal, and SOM is relatively well preserved regardless of hydroperiod or nutrient levels. SOM accumulated in peat soils is more prone to continued degradation than the SOM in the marl soils. The latter is presumably stabilized early on through direct air exposure (oxidation) and thus, it is more refractory to further diagenetic transformations such as humification and aromatization reactions.

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Corvio sandstone is a ~20 m thick unit (Corvio Formation) that appears in the top section of the Frontada Formation (Campoó Group; Lower Cretaceous) located in Northern Spain in the southern margin of the Basque-Cantabrian Basin. Up to 228 plugs were cored from four 0.3 x 0.2 x 0.5 m blocks of Corvio sandstone, to perform a comprehensive characterization of the physical, mineralogical, geomechanical, geophysical and hydrodynamic properties of this geological formation, and the anisotropic assessment of the most relevant parameters. Here we present the first data set obtained on 53 plugs which covers (i) basic physical and chemical properties including density, porosity, specific surface area and elementary analysis (XRF - CHNS); (ii) the curves obtained during unconfined and confined strengths tests, the tensile strengths, the calculated static elastic moduli and the characteristic stress levels describing the brittle behaviour of the rock; (iii) P- and S-wave velocities (and dynamic elastic moduli) and their respective attenuation factors Qp and Qs, electrical resistivity for a wide range of confining stress; and (iv) permeability and transport tracer tests. Furthermore, the geophysical, permeability and transport tests were additionally performed along the three main orthogonal directions of the original blocks, in order to complete a preliminary anisotropic assessment of the Corvio sandstone.

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With the aim of analyzing the complex physical and biogeochemical interactions at high temporal and spatial resolution in the complex estuarine waters of Alfacs Bay, a beam attenuation-based approach was used as optical proxy of different biogeochemical variables. Thus, the dataset contains the attenuation proxies as well as laboratory results from the analysis of water samples, which were used to validate our approach. In addition, the major physical forcing in the Bay was also measured.

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The Arctic Ocean and Western Antarctic Peninsula (WAP) are the fastest warming regions on the planet and are undergoing rapid climate and ecosystem changes. Until we can fully resolve the coupling between biological and physical processes we cannot predict how warming will influence carbon cycling and ecosystem function and structure in these sensitive and climactically important regions. My dissertation centers on the use of high-resolution measurements of surface dissolved gases, primarily O2 and Ar, as tracers or physical and biological functioning that we measure underway using an optode and Equilibrator Inlet Mass Spectrometry (EIMS). Total O2 measurements are common throughout the historical and autonomous record but are influenced by biological (net metabolic balance) and physical (temperature, salinity, pressure changes, ice melt/freeze, mixing, bubbles and diffusive gas exchange) processes. We use Ar, an inert gas with similar solubility properties to O2, to devolve distinct records of biological (O2/Ar) and physical (Ar) oxygen. These high-resolution measurements that expose intersystem coupling and submesoscale variability were central to studies in the Arctic Ocean, WAP and open Southern Ocean that make up this dissertation.

Key findings of this work include the documentation of under ice and ice-edge blooms and basin scale net sea ice freeze/melt processes in the Arctic Ocean. In the WAP O2 and pCO2 are both biologically driven and net community production (NCP) variability is controlled by Fe and light availability tied to glacial and sea ice meltwater input. Further, we present a feasibility study that shows the ability to use modeled Ar to derive NCP from total O2 records. This approach has the potential to unlock critical carbon flux estimates from historical and autonomous O2 measurements in the global oceans.

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This paper reviews the state of the art in processing and extraction of ocean floor manganese nodules. It briefly reviews the mining sites where the abundant rich nodules occur and also discusses the metal distribution in nodules in view of economical processing and extraction of these metal values. The paper discloses in a detailed manner the physical and chemical characteristics of nodules, including porosity, surface area, water content and the effect of temperature on crystal structure of major constituents of nodules. In the extraction aspect of nodules, the paper reviews two different extraction schemes revealed in the literature, namely hydrometallurgical treatment and pyrometallurgical treatment. The hydrometallurgical treatments include acid leaching, ammonia leaching, leaching with reducing agents and leaching after high temperature pre-treatments such as in sulfating rousting, while the pyrometallurgical processes include smelting, chlorination-vaporization and segregation. The paper also covers metal recovery processes from leach liquor. An economic survey of processing nodules has been made in terms of problems associated with metal-marketing, and impact of metal production from nodules on mineral industries.

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The physical and biological carbon pumps in the different hydrographic and biogeochemical regimes of the Atlantic Sector of the Southern Ocean are controlled by a series of coupled physical, chemical and biological processes and a project named Eddy-Pump was designed to study them. The Eddy Pump field campaign was carried out during RV Polarstern Cruise ANT-XXVIII/3 between January and March 2012. Particular emphasis was laid on the differences which occur along the axis of the Antarctic Circumpolar Current (ACC) with its associated mesoscale eddy field. The study sites were selected in order to represent (1) the central ACC with its regular separation in different frontal jets, investigated by a meridional transect along 10°E; (2) a large-scale bloom west of the Mid-Atlantic Ridge which lasted several months with conspicuous chlorophyll-poor waters to its immediate east studied by a three-dimensional mesoscale survey centred at 12°40'W; and (3) the Georgia Basin north of the island of South Georgia, which regularly features an extended and dense phytoplankton bloom, was investigated by a mesoscale survey centred at 38°12'W. While Eddy-Pump represents an interdisciplinary project by design, we here focus on describing the variable physical environment within which the different biogeochemical regimes developed. For describing the physical environment we use measurements of temperature, salinity and density, of mixed-layer turbulence parameters, of dynamic heights and horizontal current vectors, and of flow trajectories obtained from surface drifters and submerged floats. This serves as background information for the analyses of biological and chemical processes and of biogeochemical fluxes addressed by other papers in this issue. The section along 10°E between 44°S and 53°S showed a classical ACC structure with well-known hydrographic fronts, the Subantarctic Front (SAF) at 46.5°S, the Antarctic Polar Front (APF) split in two, at 49.25°S and 50.5°S, and the Southern Polar Front (SPF) at 52.5°S. Each front was associated with strong eastward flows. The West Mid-Atlantic Ridge Survey showed a weak and poorly resolved meander structure between the APF and the SPF. During the first eight days of the survey the oceanographic conditions at the Central Station at 12°40'W remained reasonably constant. However after that, conditions became more variable in the thermocline with conspicuous temperature inversions and interleavings and also a decrease in temperature in the surface layer. At the very end of the period of observation the conditions in the thermocline returned to being similar to those observed during the early part of the period with however the mixed layer temperature raised. The period of enhanced thermohaline variability was accompanied by increased currents. The Georgia Basin Survey showed a very strong zonal jet at its northern edge which connects to a large cyclonic meander that itself joins an anticyclonic eddy in the southeastern quadrant. The water mass contrasts in this survey were stronger than in the West Mid-Atlantic Ridge Survey, but similar to those met along 10°E with the exception that the warm and saline surface water typical of the northern side of the SAF was not covered by the Georgia Basin Survey. Mixed layers found during Eddy-Pump were typically deep, but varied between the three survey areas; the mean depths and standard variations of the mixed layer along the 10°E were 77.2±24.7 m, at the West Mid-Atlantic Ridge 66.7±17.7 m, and in the Georgia Basin 36.8±10.7 m.

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Even though one recognizes the physical and psychological kindness of h more and more involvement of the children to the physical and sporty activities, these programs seem more and more inaccessible to some. This article underlines the importance school déprogrammes centered on structured physical and sporty activities. In the setting of a recent survey, one asked youngsters to 5th year to take in note all their activities (as diary calendar) during two days of consecutive week. L·s children that participated in structured physical and sporty activities before and after the hours class sembkient to pull a lot more phisir of their day that those that didn't participate in these activities. Besides, seuk the young that took to structured physical and sporty activities reached the rates recommended of daily physical activity. The article proposes to the school administrators, to the parents, to the children and to the collectivities various measures encouraging the adoption of additional programs centered on the physical and sporty activities in school environment.

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Background
Increasing physical activity in the workplace can provide employee physical and mental health benefits, and employer economic benefits through reduced absenteeism and increased productivity. The workplace is an opportune setting to encourage habitual activity. However, there is limited evidence on effective behaviour change interventions that lead to maintained physical activity. This study aims to address this gap and help build the necessary evidence base for effective, and cost-effective, workplace interventions

Methods/design
This cluster randomised control trial will recruit 776 office-based employees from public sector organisations in Belfast and Lisburn city centres, Northern Ireland. Participants will be randomly allocated by cluster to either the Intervention Group or Control Group (waiting list control). The 6-month intervention consists of rewards (retail vouchers, based on similar principles to high street loyalty cards), feedback and other evidence-based behaviour change techniques. Sensors situated in the vicinity of participating workplaces will promote and monitor minutes of physical activity undertaken by participants. Both groups will complete all outcome measures. The primary outcome is steps per day recorded using a pedometer (Yamax Digiwalker CW-701) for 7 consecutive days at baseline, 6, 12 and 18 months. Secondary outcomes include health, mental wellbeing, quality of life, work absenteeism and presenteeism, and use of healthcare resources. Process measures will assess intervention “dose”, website usage, and intervention fidelity. An economic evaluation will be conducted from the National Health Service, employer and retailer perspective using both a cost-utility and cost-effectiveness framework. The inclusion of a discrete choice experiment will further generate values for a cost-benefit analysis. Participant focus groups will explore who the intervention worked for and why, and interviews with retailers will elucidate their views on the sustainability of a public health focused loyalty card scheme.

Discussion
The study is designed to maximise the potential for roll-out in similar settings, by engaging the public sector and business community in designing and delivering the intervention. We have developed a sustainable business model using a ‘points’ based loyalty platform, whereby local businesses ‘sponsor’ the incentive (retail vouchers) in return for increased footfall to their business.

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The main drivers for the development and evolution of Cyber Physical Systems (CPS) are the reduction of development costs and time along with the enhancement of the designed products. The aim of this survey paper is to provide an overview of different types of system and the associated transition process from mechatronics to CPS and cloud-based (IoT) systems. It will further consider the requirement that methodologies for CPS-design should be part of a multi-disciplinary development process within which designers should focus not only on the separate physical and computational components, but also on their integration and interaction. Challenges related to CPS-design are therefore considered in the paper from the perspectives of the physical processes, computation and integration respectively. Illustrative case studies are selected from different system levels starting with the description of the overlaying concept of Cyber Physical Production Systems (CPPSs). The analysis and evaluation of the specific properties of a sub-system using a condition monitoring system, important for the maintenance purposes, is then given for a wind turbine.