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1
Owings, Paul C. "High Gradient Magnetic Separation of nanoscale magnetite." Thesis, Kansas State University, 2011. http://hdl.handle.net/2097/12020.
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Master of ScienceDepartment of Civil Engineering
Alexander P. Mathews
Nanoscale magnetite is being examined for possible uses as an adsorbent of heavy metals and for the enhancement of water treatment processes such as stripping of trichloroethylene (TCE) from contaminated water supplies and wastewaters. Methods for recovering nanoscale magnetite must be developed before the particles can be used in water treatment processes. This is necessary because expelling high amounts of particles into the environment will be unacceptable and costly; if captured they can be reused; additionally, they could potentially cause environmental impacts due to their stability in an aqueous environment and possible toxicity. Nanoscale magnetite is superparamagnetic, so it has a high magnetic susceptibility, and hence it is very attracted to magnetized materials. Utilizing the magnetic properties of magnetite may be one possible means of separating the particles from a treatment process. High Gradient Magnetic Separation (HGMS) has been studied for the separation of micron and even tenths of a micron size particles, but there is little experimental data for HGMS of nanoscale magnetite. This research looks to filter nanoscale magnetite through a HGMS and determine the capture efficiency of the filter. Subsequently, the filter was backwashed to determine particle recover efficiencies. The flow rate was adjusted to determine the dependency of particle capture efficiency on cross sectional velocity through the filter. Additionally, particle loading was changed to better understand the correlation of particle loading with capture efficiency. Filtrations for nanoscale magnetite dispersed with sodium tripolyphosphate were also completed as well as filtrations of nanoscale magnetite coated with silica and magnetite silica composites. Experimental data in this research indicates that magnetite nanoparticles can be captured at 99.8% efficiency or higher in a well-designed filtration system. Capture efficiencies around 99.8% have been found for magnetite. The silica coated magnetite and magnetite silica composites were captured at efficiencies as high as 96.7% and 97.9%, respectively. The capture efficiency of the dispersed magnetite is lower than non-dispersed magnetite and most promising at relatively low fluid flow velocities and particle loadings. The maximum capture efficiency for dispersed magnetite particles was 90.3%. Both magnetite and dispersed magnetite were successfully recovered using backwash at pH of 10 to 11.
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Yates, Gillian. "Environmental magnetism applied to archaeology." Thesis, University of Liverpool, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329625.
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Ying, Tung-Yu. "Novel environmental processes using electric and magnetic fields." Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/20156.
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Lees, Joan Anne. "Modelling the magnetic properties of natural and environmental materials." Thesis, Coventry University, 1994. http://curve.coventry.ac.uk/open/items/aa273a60-0c0d-a613-81b9-b95cc2ec3fdd/1.
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Magnetic properties have been used to characterize natural and environmental materials. An evaluation of magnetic properties, for the modelling of sources of materials and minerals, has been completed. A methodological framework has been developed for the application of magnetic techniques to studies involving the quantification of sources of materials and minerals in any environment. the framework includes the idntification of sources using magnetic reconnaissance and multi-variate statistical classification techniques. magnetic measurements used are susceptibility (both field and laboratory), remanence and magnetization measurements. the linear additivity of magnetic measurements, and classification and linear modelling techniques, ahve been tested using datea for artificial laboratory mixtures and hypothetical mixing experimentrs. The limitations of using magnetic properties with these statistical and mathematical techniques are defined. the famework allows for hte testing of suitabililty of manetic modelling techniques in any sourceing study.
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Egli, Ramon. "Environmental influences on the magnetic properties of lake sediments." Zürich : [s.n.], 2003. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=15090.
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Quboa, Kaydar Majeed. "Environmental electric and magnetic fields : measurements and communications implications." Thesis, University of Salford, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.258349.
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Lee, Seungwoo. "Development of magnetic composite photocatalytic particles for environmental applications." [Gainesville, Fla.] : University of Florida, 2004. http://purl.fcla.edu/fcla/etd/UFE0008266.
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Augé, Laurent J. (Laurent Jacques) 1980. "Structural magnetic induction dampers in buildings." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/29332.
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Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2003.Includes bibliographical references (leaf 49).
This thesis discusses the feasibility of structural magnetic induction dampers for dampening mechanical vibrations in buildings subjected to strong dynamic excitations. The concept of energy harvesting in various fields of engineering is first examined. Then it is applied to the design of magnetic induction dampers in buildings. Various implementations of these dampers are proposed and the related expected performances are estimated. Simulations on buildings modeled as discrete multiple-degree-of-freedom shear beams subjected to earthquakes quantify the results and allow for a comparison of the performances with nonisolated and base-isolated buildings. This study demonstrates the potential efficiency of such dampers for harvesting mechanical energy in buildings and encourages further developments on this topic.
by Laurent J. Auge.
M.Eng.
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Yu, L. "Environmental applications of mineral magnetic measurement : Towards a quantitative approach." Thesis, University of Liverpool, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234577.
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Crook, Nigel Paul. "The application of quantitative environmental magnetic measurements to sedimentary systems." Thesis, Manchester Metropolitan University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248812.
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Hannam, Jacqueline Ann. "Processes and timescales of secondary magnetic mineral formation in topsoils." Thesis, University of Liverpool, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366393.
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Ramanan, Baheerathan. "Quantifying mass transport processes in environmental systems using magnetic resonance imaging (MRI)." Thesis, University of Glasgow, 2011. http://theses.gla.ac.uk/2974/.
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Understanding the transport behaviour of pollutants is key to enhance remediation strategies and to inform predictive models of pollutant behaviour in environmental and engineered systems. This work investigates magnetic resonance imaging (MRI) as a methodology for imaging heavy metal, molecular and nanoparticle transport in two different saturated porous systems: biofilms and saturated porous geologic media (gravel). While most renowned for its use in medicine, magnetic resonance imaging (MRI) is enabling us to image the transport of heavy metals, macro-molecules and nanoparticles inside biofilms and porous columns in real time. This is achieved using either ions which are paramagnetic (e.g. Cu2+) or molecules labelled with paramagnetic ions (e.g. Gd3+) or superparamagnetic (e.g. nanomagnetite) nanoparticles. Presence of these tracers causes a concentration dependent shortening of relaxation times (T1 or T2) of the surrounding 1H nuclei and thus creates noticeable changes in the MRI signal. Critically, this enables the transport of (super)paramagnetic ions, molecules or nanoparticles through the biofilm or porous geological media to be imaged. Moreover, the actual concentrations of molecules can be quantified, as changes in relaxation rates have a linear relationship with the concentration of the tracer molecules. Hence, MRI can be used not only to track but also to quantify the transport of (super)paramagnetic molecules inside biofilms and saturated porous columns. The key advantages of MRI over other techniques are its ability to image inside systems opaque to other methods and its ability to collect data non-invasively, hence the system is unperturbed by the analysis. In this study, the transport of Gd-DTPA, a commonly used MRI contrast agent, was successfully imaged through phototrophic biofilms of 10 and 2.5 mm thicknesses. To improve spatial resolution, for the 2.5 mm thickness biofilm, a bespoke 5 mm diameter RF coil was constructed. The comparison of spatially distributed, time-varying concentrations of Gd-DTPA inside the biofilms with diffusion models illustrated that transport was via both diffusion and advection. This work illustrated the potential of using paramagnetically labelled molecules to quantify molecular pollutant transport and fate in biofilms. MRI was also used to image heavy metal trasport in artificial biofilms (composed of agar and bacteria) to test the suitability of an existing adsorption-diffusion model to represent heavy metal transport and fate in biofilms. While the diffusion coefficients and adsorption constants estimated were appropriate, discrepancies between the model and the data illustrates models may need to be developed further to incorporate factors such as concentration dependant diffusion or cell lysis. Finally, the ability to image inside opaque systems was further exploited to image nanoparticle transport inside a coarse-grained packed column. This was undertaken to illustrate the potential for MRI to image nanoparticle pollutant transport in systems relevant to river beds and sustainable urban drainage systems (SUDS). MRI was successfully used to image the nanoparticle transport, with significant transport inhibition was observed in positively charged nanoparticles compared to negatively charged nanoparticles due to permanent attachment.
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Heil, Clifford William. "Paleo-and environmental magnetic studies of late Cenozoic estuarine, lacustrine, and terrestrial sediments /." View online ; access limited to URI, 2008. http://0-digitalcommons.uri.edu.helin.uri.edu/dissertations/AAI3314457.
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Elhelou, Othman. "Magnetic Susceptibility Mapping of Fly Ash in Soil Samples Near a Coal-Burning Power Plant in Pointe Coupee Parish, Louisiana." Thesis, University of Louisiana at Lafayette, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1592981.
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Magnetic susceptibility is a property that can be used to effectively determine the compositional changes of mineral materials in soil. The objective of this study is to detect the presence of magnetic particles related to the migration of fly ash from a nearby coal-burning power plant over parts of Pointe Coupee Parish, LA. This is based on the idea that the fly ash that is released into the atmosphere during the coal burning process contains heavy metals and magnetic particles in the form of ferrospheres, which can be used to trace back to the source. Maps of the top and sub soil were generated to differentiate the magnetic susceptibility values of the heavy metals potentially attributed to the migration and settling of fly ash onto the surface from any pre-existing or naturally occurring heavy metals in the sub soil. A 60 km2 area in Pointe Coupee Parish was investigated in approximately 0.5 km2 subsets.
At each site, a minimum of 20 magnetic susceptibility measurements were obtained using a field probe along with discrete surface and subsurface samples collected for subsequent laboratory analysis. Samples of fly ash obtained directly from the source were also analyzed to verify the field and laboratory analysis. Contour maps representing the spatial distribution of the fly ash along with histograms of magnetic susceptibility values, reflective light microscope, and chemical analysis indicate a correlation between the proximity to the power plant and the predominant wind direction. Acquisition curves of the isothermal remanent magnetization demonstrate the presence of predominantly low coercivity minerals (magnetite) with a small amount of a high-coercivity phase. The microstructure of the magnetic fractions of the fly ash along with select top and sub soil samples were observed using a reflective light microscope for identifying and confirming the presence of ferrospheres associated with fly ash.
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Wadsworth, Emilie R. "The identification and characterisation of the North Atlantic Heinrich Events using environmental magnetic techniques." Thesis, University of St Andrews, 2006. http://hdl.handle.net/10023/2782.
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Heinrich Events (HEs) define intervals of major ice rafting from the Laurentide Ice Sheet (LIS) into the North Atlantic during that last glacial period. The discovery of potential European-sourced precursors to HEs suggest that the smaller, but climactically sensitive, European ice sheets (EIS) may have played a role in the triggering of HEs and their impact on global climates. Environmental magnetism has proved itself to be a useful, rapid and non-destructive tool in the identification and quantification of provenance in sediments from various depositional environments. In this work, environmental magnetic analyses are applied to marine sediment records from the European margin of the NE Atlantic and known to contain ice-rafted debris (IRD) from both LIS and EIS sources. The primary aim in the work of this thesis is to evaluate the methodology as a means of distinguishing IRD provenance. From the data obtained here it is possible to identify several magnetic events that correspond to the HEs and other layers of detrital material and which correlate well to previous standard petrological analyses performed on the same core materials. Magnetic signatures differ within the HEs, suggesting a changing balance of input from multiple sources as opposed to a single LIS source. The data suggest a phasing of these compositional differences through individual HEs. The potential of using environmental magnetic techniques in the identification of IRD provenance within marine sediments is discussed, as is the significance of the observed provenance variations within the cores studied.
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Cheema, Mahmood A. (Mahmood Ahmad). "Environmental health, risk analysis and safety aspects of nuclear magnetic resonance and spectroscopy systems." Thesis, Massachusetts Institute of Technology, 1991. https://hdl.handle.net/1721.1/129503.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1991.Title as it appears in the June, 1991 M.I.T. Graduate List: Geochemistry and petrogenesis of basalts from Broken Ridge and Naturaliste Plateau, S.E. Indian Ocean.
Includes bibliographical references (leaves 47-48).
by Mahmood A. Cheema.
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1991.
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Halliday, Jennifer M. "Magnetic characterisation and palaeointensity analysis of rocks from selected I-type granitic plutons." Thesis, Kingston University, 2008. http://eprints.kingston.ac.uk/20395/.
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Absolute palaeointensity data are crucial to investigating the behaviour of the geomagnetic field. Long-term global palaeomagnetic databases are compiled with the aim of documenting the evolution of the geomagnetic field. However the temporal and spatial distribution remains limited, partly due to a lack of 'suitable' material in critical time windows, or poor magnetic behaviour of these rocks during experiments. Therefore it would be useful to have other potential sources of palaeointensity data in the surface rock record. Granitic intrusions occur frequently throughout the geological record, are often well exposed and well dated. However, granitic rocks have not previously been fully exploited in palaeointensity studies, due to their perceived lower primary magnetic content and problems associated with the stability of their magnetic signatures. Plutons show an internal grain-size variation and contain mafic enclaves, xenoliths and sheets derived from the primary melt. Therefore a range of magnetic behaviour, and hence a range of potential suitability for palaeointensity work can be expected within a single pluton. To our knowledge, there are no recorded rock magnetic or palaeomagnetic investigations addressing the question of whether granites are generically unsuitable, for palaeointensity work. To test this hypothesis, three I-type granitic plutons were characterised in terms of their magnetic suitability for palaeointensity analysis - including the Ross of Mull Pluton and Loch Doon Complex, SW Scotland and selected intrusions from the Coastal Batholith, Peru. Characterisation was achieved though extensive rock magnetic, palaeomagnetic and SEM analysis which enabled the magnetic properties of the samples to be determined. 180 samples were investigated using the Coe-modified Thellier technique to determine whether reliable palaeointensity data can be obtained. Magnetic characterisation and SEM analysis reveal that the magnetic mineralogy of the granitic intrusions is dominated by multidomain (MD) Ti-poor titanomagnetite. Exsolution textures observed in the Fe-Ti oxide grains are responsible for creating grains with SD-MD grain sizes. Stable univectoral remanences are usually accompanied by narrow unblocking temperatures where most NRM is lost between 560- 580°C. This makes obtaining acceptable PI data difficult, but by no means impossible. PI experiments were of variable success. Experiments including pTRM and pTRM tail checks and standard acceptance criteria were used to assess the quality of the results. The Ross of Mull rocks yielded no PI determinations. However, the Loch Doon Complex and intrusions from the Coastal Batholith were more triumphant with success rates of 28% and 57% respectively. The Loch Doon pluton (408Ma) is calculated to have a pluton average 8.2[mu]T with standard deviation 4[mu]T. The main reasons for failure of PI experiments are weak NRM, alteration and unstable MD behaviour. Experimental success correlates with the perceived geological complexity at each field area, where it is observed that simpler intrusions with less complicated cooling histories yield rocks with a: more stable magnetic signature and allow PI data to be derived. Results indicate that the more mafic rocks sampled in each pluton produced the best quality PI data. PI estimates were made on samples from Peruvian intrusives. The Anta ring dyke and Chasquitambo pluton give a site average of 15[mu]T with standard deviation 13.5[mu]T. Large deviation is caused by a single estimate, which at 46.7±18.4[mu]T is significantly different from the values found from other sites. Remaining sites have PI within error, however it should be noted that according to the K-Ar dates (Wilson, 1975) emplacement of the two separate intrusions occurred millions of years apart, 70.7±1.6Ma and 61±0.7Ma respectively. Samples from the Sayan pluton (61.2±0.4Ma) yield an average PI 25.4[mu]T ±7.7[mu]T. Arai plots are dominated by curvature, pTRM checks and rock magnetic experiments indicate that curvature is not caused by alteration and can be attributed to MD phenomena. PI estimates are made using the end-point method and from linear segments were possible, consistency between the two methods was demonstrated. This research reveals the potential of I-type plutons to provide reliable palaeointensity data.However, the PI data presented here must be considered as preliminary as no cooling rate or anistropy corrections have been applied.
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Hakami, Othman. "Synthesis and use of magnetic nanoparticles for the adsorption of mercury from water." Thesis, University of Southampton, 2012. https://eprints.soton.ac.uk/348890/.
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This study used magnetite (Fe3O4) nanoparticles (NPs), mesoporous silica coated magnetite NPs (SCMNPs) and thiol functionalised silica-coated magnetite nanoparticles (SH-SCMNPs) for Hg(II) removal and recovery from water. The Fe3O4 NPs were prepared via conventional co-precipitation methods. Mesoporous silica coating was created on dense liquid-silica coated magnetite NPs (DLSC-Fe3O4 NPs) using cetyltri-methyl-ammonium chloride (CTAC) as molecular templates and followed by a sol-gel reaction. SCMNPs were functionalised with 3-MPTMS using the co-condensation method. Functionalisation of SCMNPs with this specific organic group was performed to enhance the selectivity of the magnetic NPs towards Hg(II). The characteristics of these particles were assessed at different stages in the production process. The hydrodynamic particle size distribution increased from an average diameter of ~75 nm for Fe3O4 NPs to ~105 nm after silica coating, and was found to be ~111 nm after functionalisation with thiol. The particles were found to be almost spherical with a uniform mesoporous structure with a pore size of ~2.1 nm. The particles were strongly responsive to an external magnetic field making separation from solution possible in less than 1 minute using a permanent magnet. Batch tests were used to evaluate the feasibility of the prepared NPs for the adsorption and desorption of Hg (II) from synthetic wastewater. SH-SCMNPs displayed a high removal efficiency for Hg(II) uptake, with 90% of Hg(II) removed during the first 5 minutes and equilibrium in less than 15 minutes. The adsorption efficiency was highly pH dependant. Adsorption was not affected by the majority of coexisting cations and anions under the conditions tested. 3 M HCl and thiourea in a 3 M HCl solution was an effective eluent for the desorption of adsorbed-Hg on SCMNPs and SH-SCMNPs respectively. This did not result in the destruction of the nanoparticles and they could subsequently be reused, without loss of their activity, in further adsorption tests. The adsorption characteristics of the particles were quantified in a series of isotherm experiments using Hg(II) solution concentrations of between 40 and 1000 μg L−1 at adsorbent concentrations of 4 and 8 mg L-1. The adsorption capacity was higher than for other commonly used adsorbents. Both the Langmuir and Freundlich isotherm models were applied to the isotherm data and the maximum adsorption capacity was achieved when the ratio of adsorbent to adsorbate was low. A semi-continuous method for using the process at a lab scale was developed and was found to be successful in the removal and recovery of Hg(II) and confirmed the results of the batch experiments.
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Horton, Lindsey B. "High-Resolution Environmental Magnetic Properties and Relative Geomagnetic Paleointensity of IODP Expedition 339 (Site U1389)." Thesis, University of Louisiana at Lafayette, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10250510.
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The Mediterranean Outflow Expedition, which concluded in early 2012, provides an outstanding opportunity to address paleoceanographic questions about the evolution of the Mediterranean and North Atlantic climate system over the past six million years. The expedition recovered over 6 km of sediments. This provides an excellent archive for the study of paleoclimatic, paleoceanographic, and other paleoenvironmental changes and will also provide chronostratigraphic, plate tectonic, and geomagnetic constraints. Results are presented from the upper part of Site U1389 (36 25.515’N; 7 16.683’W), which is located approximately 90 km west of the Spanish city of Cadiz, in a water depth of 644 mbsl. This site is located in the “channels and ridges” sector of the larger Cádiz Contourite Depositional System (CDS). The sedimentary section extends for 990 m from the early Pliocene to Holocene and is represented by a thick, rapidly accumulated, and very uniform series of contouritic sediment. Paleomagnetic and rock magnetic measurements were carried out at 1-cm resolution on 36 m of U-channel samples from the composite stratigraphic section with the goal of extracting a high-resolution record of the magnetostratigraphy, the relative geomagnetic paleointensity, and the variability of the paleoenvironmental conditions. Step-wise demagnetization of the natural remanent magnetization yielded a well-defined interval over a portion of the Holocene with the deepest part of the section being younger than 60 ka. Sediment ages were determined by using an age model based on proprietary oxygen isotope data from Francisco J. Sierro. Interpolation of the age model shows sedimentation rates averaging near 70 cm/kyr. A relative paleointensity record was extracted by normalizing the NRM by ARM. These results along with the lack of power in the Milankovitch frequencies in the spectral analysis of the NRM/ARM and NRM/k signals support the interpretation that the RPI record is not influenced by environmental factors and accurately represents changes in global-scale paleomagnetic field intensity. Interpretation of the environmental records indicates cyclic warming and cooling, as that correlates well with sapropels, finer grains and warmer climate, and Heinrich Events, coarser grained IRD and cooling climate.
The comparison of IODP U1389 to proven records of GLOPIS reveals a high fidelity with few discrepancies and due to the locality of the site, proves the reliability of the RPI records. All usual criteria for paleointensity studies suggest that the upper portion of Site U1389 yielded a reliable high-resolution record of relative paleointensity, which provides a vital basis for global correlations of future studies.
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D'Agostino, Carmine. "Advanced NMR techniques in sustainable chemistry." Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610457.
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Prettyman, Johnny B. "Comparison of Selected Differential Producing, Ultrasonic, and Magnetic Flow Meters." DigitalCommons@USU, 2014. https://digitalcommons.usu.edu/etd/3873.
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Flow meters are used to measure flow accurately. There are many different flow meters and it is necessary to know which will function best for specific situations. A wide variety of flow meters were selected for the study to assist in showing that each flow meter has its tradeoffs. The selected meters include: three types of Venturi meters, a wedge meter, a V-cone meter, an electromagnetic flow meter, and an ultrasonic flow meter. The characteristics researched in this study are discharge coefficient (Cd) over a range of Reynolds numbers (Re), head loss across each flow meter, life, and cost of meter. Each meter was tested over a wide range of Re to find the corresponding Cd and head loss. The life and cost of each meter were researched and estimated based on the flow meter companies and local distributor’s findings. With the findings, the tradeoffs are illustrated and will assist buyers in selecting a flow meter that will best fit their needs. While there are more flow meters available than was tested, the current study can direct buyers in a correct process of selecting meters for all situations.
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Verdugo, Gonzalez Brenda. "Regenerable Adsorbents for Removal of Arsenic from Contaminated Waters and Synthesis and Characterization of Multifunctional Magnetic Nanoparticles for Environmental and Biomedical Applications." Diss., The University of Arizona, 2011. http://hdl.handle.net/10150/202532.
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The present work is divided into two sections. The first section deals with the synthesis of regenerable adsorbents for the removal of arsenic from contaminated waters. An adsorbent based on carboxymethylated polyethylenimine grafted agarose gels was synthesized and characterized as a regenerable synthetic ferric oxide adsorbent with high capacity for arsenate ions at pH 3.0. Similarly, four metal ion chelating adsorbents based on dipicolylamine were synthesized and characterized with respect to their Cu(II), Fe(III) and As(V) adsorption capacities. The most efficient adsorbents were Nov-PEI-DPA and Nov-TREN-DPA. Additionally, a commercial ion exchange resin was modified with permanganate to oxidize arsenite into arsenate. A complete oxidation-adsorption system was proposed in which a column packed with the oxidation resin was connected in series with an adsorbent column composed of the polyethylenimine grafted agarose gels.The second section involved work with magnetic nanoparticles. First, composite adsorbents consisting of magnetic particles encapsulated within agarose beads with and without grafted iminodiacetic acid (IDA) chelating groups were synthesized. The adsorption capacity of the adsorbents for Cu(II), Fe(III) and As(V) at different concentrations was investigated. Batch experiments were carried out to determine the Fe(III) and As(V) adsorption isotherms for the magnetic Novarose-IDA. Regenerability of the adsorbent was achieved with a pH change of the inlet solution, without affecting its magnetic or adsorption properties.Magnetic composite particles were synthesized for biomedical applications. First, magnetic nanoparticles were coated with silica and then used for gold nanoshell production. These nanoshells were functionalized with a Brij S10 derivative, containing carboxylic groups, using dodecanethiol as a bridging agent to incorporate a fluorescent biomolecule.Finally, magnetic and gold particles were encapsulated in PLGA nanoparticles. Docetaxel was loaded on these multifunctional nanoparticles and released studies were performed at 37°C. The presence of magnetite, colloidal gold and gold nanoshells in the PLGA nanoparticles was revealed by the coloration acquired by the polymeric nanoparticles. The release of drug from the polymeric nanoparticles showed a biphasic behavior with an initial burst followed by a prolonged slow release. There was no effect of the presence of magnetic or metallic particles on docetaxel release.
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Clawson, Bradley C. "The Effects of Upstream Straight Pipe Length on Magnetic Flow Meter Accuracy." DigitalCommons@USU, 2016. https://digitalcommons.usu.edu/etd/5053.
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In closed conduit water systems, being able to accurately measure flow is absolutely essential. For many meter designs, including electromagnetic induction meters (also known as magnetic flow meters), the greatest accuracy is achieved when the device is calibrated correctly. Optimal meter accuracy often depends on the flow conditions associated with the upstream geometry in the pipe system. Manufacturers typically give standards for the length of straight pipe required upstream of the meter. These standards vary, however, and do not address every possible configuration that may be installed upstream of the straight pipe requirement.
An investigation on the effects of the length of straight pipe between a single 90° elbow and the upstream side of magnetic flow meters was completed in this research. Eleven 10-inch meters were chosen for testing. The procedure included a baseline test with more than forty diameters of straight pipe between the elbow and the meter. The accuracy of the meter was determined over a range of flow velocities typical for operation of this type and size of meter. Further tests were performed with the meter installed only three diameters downstream of the elbow. These tests constitute Phase I. In Phase II, four meters were tested with the upstream pipe length varying from a close-coupled installation to ten diameters of straight pipe between the elbow and the meter to observe variances in accuracy with distance from the elbow.
The intent of the research was to show whether manufacturer accuracy specifications are achievable in actual application. It was determined that very few meters meet the manufacturer’s specification for accuracy even when installation requirements were met. Post-factory calibrations and minimization of velocity profile disruption through consideration of upstream geometry is recommended.
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Walrod, John Hamilton II. "ARSENIC REMOVAL WITH A DITHIOL LIGAND SUPPORTED ON MAGNETIC NANOPARTICLES." UKnowledge, 2017. http://uknowledge.uky.edu/chemistry_etds/83.
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Exposure to arsenic (As) in water, the ubiquitous toxin that poses adverse health risks to tens of millions, is the result of both anthropogenic and geochemical mobilization. Despite recent publicity and an increased public awareness, the dangers associated with arsenic exposure rank among the top priorities of public health agencies globally. Existing sequestration applications mainly include reductions and adsorption with zero-valent metals and their oxides. The performance of adsorption media is known to preferentially favor aqueous As(V) over As(III) due to the charge of the dissolved oxyanion. Magnetic nanoparticles (MNP) have been the focus of multidisciplinary research efforts for the removal of aqueous toxic metals and metalloids since they can be magnetically separated from the treated water. This improves isolation and allows for regeneration of the MNP, reducing cost and resource consumption. This research is focused on As(III & V) sequestration through the use of synthetic ligands N,N’bis(2-mercaptoethyl)isophthalamide (abbreviated BDTH2) and 2,2’- (isophthaloybis(azanaediyl))bis-3-mercaptopropanoic acid (abbreviated ABDTH2). Additionally, As(III) sequestration with ABDTH2 functionalized on silica core-shell MNP (ABDTH2 MNP), magnetite MNP (ABDTH2@MNP), and commercial silica beads (ABDTH2 Si60) is demonstrated. Both BDTH2 and ABDTH2are effective precipitation agents for the removal of As(III) through the formation of S-As covalent bonds. ABDTH2MNP reduced a 200 ppb As(III) batch solution to below 10 ppb at pH 5,7, and 9. Additionally, complete removal was achieved in the presence of anions at concentrations of 200, 500, and 1000 ppb. This system was evaluated for the removal of total arsenic from industrial solutions accumulated during the production of renewable biogas in landfills. Direct precipitation with BDTH2 and ABDTH2 was inhibited by the complex matrix. However, batch removal with ABDTH2@MNP was effective in removing 82% of the inorganic arsenic. Sequestration of arsenic and speciation from these industrial solutions remains a challenge.
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Forssén, Ulla. "Extremely low frequency magnetic fields and breast cancer /." Stockholm, 2003. http://diss.kib.ki.se/2003/91-7349-532-8/.
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Deadman, Jan-Erik. "Estimation of exposures to extremely low frequency electric and magnetic fields." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ29919.pdf.
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Crosby, Christopher James. "Application of mineral magnetic measurements as a pollution proxy for urban road deposited sediment." Thesis, University of Wolverhampton, 2012. http://hdl.handle.net/2436/265493.
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Road Deposited Sediment (RDS) is an important pathway of pollution material in the urban environment. Traditional particulate matter (PM) monitoring methods are typically expensive and time consuming. To date, urban sediment studies have not fully explored the application of mineral magnetic technologies as an alternative to characterise RDS or, perhaps more importantly, their use as particle size proxy. Therefore, this study addresses these issues by determining the extent of any linkages between magnetic properties and the physio-chemical concentrations of RDS. Investigations have focussed on a spatial temporal study (2008-10) of RDS from the City of Wolverhampton (n = 546) and a similar ‘snap-shot’ study of eight selected town and cities across the UK (n = 306), plus a comparison investigation linked to regional monitoring of air sampling units (ASU) (n = 208). A suite of analytical approaches, namely mineral magnetism, laser diffraction, X-Ray Fluorescence spectroscopy (XRF), Scanning Electron Microscopy (SEM) and Loss on Ignition (LOI), were employed to characterize sample properties. Data interrogation identified mainly weak correlations exist between most mineral magnetic parameters and particle size classes (i.e. sand, silt and clay) and respiratory health-related size classes (i.e. PM10, PM2.5 and PM1.0). The few strongest correlations (p <0.001) were found between mineral magnetic concentration and
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Betson, Tatiana. "Deuterium isotopomers as a tool in environmental research." Doctoral thesis, Umeå : Univ, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-938.
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Gutierrez, Angela. "DEVELOPMENT OF MAGNETIC NANOCOMPOSITE MATERIALS AS REUSABLE ADSORBENTS FOR CHLORINATED ORGANICS IN CONTAMINATED WATER." UKnowledge, 2019. https://uknowledge.uky.edu/cme_etds/107.
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The constant growth in population worldwide over the past decades continues to put forward the need to provide access to safe, clean water to meet human needs. There is a need for cost-effective technologies for water and wastewater treatment that can meet the global demands and the rigorous water quality standards and at the same maximizing pollutant efficiency removal. Current remediation technologies have failed in keeping up with these factors without becoming cost-prohibitive. Nanotechnology has recently been sought as a promising option to achieve these goals. The use of iron oxide magnetic nanoparticles as nanoadsorbents has led to a new class of magnetic separation strategies for water treatment. We have developed magnetic nanocomposite systems able to capture polychlorinated biphenyls (PCBs), as model organic pollutants, in aqueous solution, providing a cost-effective water remediation technique. Two distinct methods were employed to develop these polyphenolic nanocomposite materials. The polyphenolic moieties were incorporated to create high affinity binding sites for organic pollutants within the nanocomposites. The first method utilized a surface initiated polymerization of polyphenolic-based crosslinkers and co-monomers on the surface of iron oxide magnetic nanoparticles to create a core-shell nanocomposite. The second method utilized a bulk polymerization method to create macroscale films composed of iron oxide nanoparticles incorporated into a polyphenolic-based polymer matrix, which were then processed into microparticles. Both methods produce nanocomposite materials that can bind chlorinated organics, can rapidly separate bound organics from contaminated water sources using magnetic decantation, and can use thermal destabilization of the polymer matrix for contaminant release and material regeneration. The polyphenol functionalities used to bind organic pollutants were quercetin multiacrylate (QMA) and curcumin multiacrylate (CMA), which are acrylated forms of the nutrient polyphenols quercetin (found in berries) and curcumin (found in turmeric), both with expected affinity for chlorinated organics. The affinity of these novel materials for PCB 126 was evaluated at equilibrium conditions using a gas chromatography coupled to electron capture detection (GC-ECD) for quantification purposes, and the data was fitted to the nonlinear Langmuir model to determine binding affinity (KD) and maximum biding capacity (Bmax). The KD values obtained demonstrated that the presence of the polyphenolic-based moieties, CMA and QMA, as crosslinkers enhanced the binding affinity for PCB 126, expected to be a result of their aromatic rich nature which provides sites for π – π stacking interactions between the nanoparticle surface and the PCBs in solution. These values are lower that the reported affinity coefficients for activated carbon, which is the gold standard for capture/binding of organic contaminants in water and waste water treatment. Furthermore, upon exposure to an alternating magnetic field (AMF) for a period of 5 minutes, over 90% of the bound PCB on these materials was released, offering a low-cost regeneration method for the nanocomposites. Additionally, this novel regeneration strategy does not require the use of large volumes of harsh organic solvents that oftentimes become harmful byproducts. Overall, we have provided strong evidence that these novel nanocomposites have a promising application as nanoadsorbents for specific organic contaminants in contaminated water sources providing high binding affinities, a low-cost regeneration technique and are capable of withstanding use under environmental conditions offering a cost effective alternative to current remediation approaches.
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Van, Peer Tim Eelco. "Palaeomagnetic, astrochronological, and environmental magnetic perspective on Oligocene-Miocene climate, using drift sediments from the northwest Atlantic Ocean." Thesis, University of Southampton, 2017. https://eprints.soton.ac.uk/416832/.
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The Antarctic ice sheet oscillated between nearly deglaciated and near-modern proportions, sometimes within ~110 kyr, during transient glacial phases of the Oligocene-Miocene icehouse world (5.33-33.9 Ma). Ice sheet hysteresis is closely coupled with carbon-cycle feedback mechanisms that are strongly affected by ocean circulation. However, the absence of high-resolution records representing the North Atlantic end member, a key region driving modern climate variability and ocean circulation, hamper full understanding of Oligocene-Miocene ocean circulation and climate. In this thesis, I integrate palaeomagnetic, X-ray fluorescence (XRF), and environmental magnetic records to date and reconstruct current variability from contourite drift sediments, recovered at Integrated Ocean Drilling Program (IODP) Site U1406 (northwest Atlantic). The revised splice ensures stratigraphic continuity for the studied section. The presented novel palaeomagnetic data processing protocol, which is applicable to all weakly magnetised sediments, ensures the use of only high quality directional data for the construction of a reliable magnetostratigraphy between Chrons C6Ar – C9n (21-27 Ma). Astronomical tuning using XRF-based ln(Ca/K), a proxy for CaCO3 content, provides independent dates for the identified geomagnetic reversals. I determine the best age estimates of reversals using a set of criteria to reconcile the Oligocene-Miocene geomagnetic polarity time scale. Congruent obliquity-paced CaCO3 cycles at Ocean Drilling Program Site 926 (equatorial Atlantic) and IODP Site U1406 suggest that one corrosive bottom water mass influences the CaCO3 content of the boreal Atlantic. The location and occurrence of contourite drift sediments at IODP Site U1406 advocates that the Deep Western Boundary Current (DWBC) is the candidate for such corrosive bottom waters. DWBC variability around the Oligocene-Miocene Transition (~23 Ma) is traced using the detrital magnetic fraction, containing titanohaematite, recognised through detailed rock and environmental magnetic measurements. During the last ca. 1 Myr of the Oligocene, the decrease in CaCO3-corrected concentration and coercivity of titanohaematite indicates an invigorated DWBC. If these characteristics of the DWBC are substantiated, this will have major implications for CO2 reconstructions on orbital time scales and Oligocene-Miocene climate models.
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Rodericks, Michele Melanie. "The effect of applied and magnetic fields on the crystallisation of hydrocarbons." Thesis, Brunel University, 2003. http://bura.brunel.ac.uk/handle/2438/9219.
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This thesis provides a background on the effects of applied and magnetic fields on crystallisation, and summarises the analytical techniques employed for characterisation and analysis. The study of applied fields was carried out on the crystallisation of one main system-solid nonadecane. This was then studied further to establish the effects of a solvent and a mixed solid system on the crystallisation of nonadecane. The systems studied were the crystallisations of: static and dynamic nonadecane, static and dynamic nonadecane in heptane, static and dynamic nonadecane and heneicosane, static and dynamic nonadecane and heneicosane in heptane and static and dynamic nonadecane and crude oil. The results of these studies showed that the magnetic and applied fields can affect electrostatic forces in molecular solids. It also showed that even the weakest of these forces, Van der Waals forces are affected by applied and magnetic fields.
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Kendzel, Mitchell J. "Gravity Acts as an Environmental Cue for Oriented Movement in the Monarch Butterfly, Danaus plexippus (Lepidoptera, Nymphalidae)." University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1595847969427021.
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Jarrett, Jordan Clark. "Partially Closed Valve Effects on Electromagnetic Flow Meter Accuracy." DigitalCommons@USU, 2016. https://digitalcommons.usu.edu/etd/5006.
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As the need to manage water resources increases, the ability to accurately measure use becomes crucial. In industry, measurement inaccuracies can cost either the supplier or consumer large amounts of money or even result in a depleted resource. Generally, flow meters need a flow profile to be fully developed to optimize measurement accuracy.
In order to produce accurate measurements, most flow meters require a straight section of pipe immediately upstream of the meter. The straight pipe helps to develop the flow profile and produces flow conditions that are as ideal as possible. In many field installations, space restrictions lead to meters being installed with reduced straight pipe between a flow disturbance and the meter.
Electromagnetic flow meters are referred to by several different names including: magnetic flow meter, mag meter or mag. The electromagnetic flow meter has grown in popularity in recent years as technology has improved and costs have decreased. Manufacturers commonly claim that their meters can produce highly accurate flow measurements, some as low as ±0.10%, with reduced upstream straight pipe requirements as low as 0 pipe diameters between a disturbance and the meter itself.
The results of this study provide quantified error associated with a partially closed butterfly valve on electromagnetic flow meter accuracy. The results show the effect of four valve openings (25%, 50%, 75%, and 100% open), at five locations downstream of the valve (1, 3, 5, 10, and 20 pipe diameters), and at two different meter orientations to the valve shaft. It was concluded in the study that twenty pipe diameters of length are required to produce accurate measurements (within the manufacturer’s specified accuracy) when a magnetic flow meter is installed downstream of a throttling butterfly valve. Surprisingly, the largest effect to the meter’s accuracy unexpectedly occurred when the upstream butterfly valve was fully open and not when it was in a throttling position.
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Saracoglu, Mehmet. "FROTH FLOTATION PERFORMANCE ENHANCEMENT BY FEED CAVITATION AND MAGNETIC PLASTIC PARTICLE ADDITION." UKnowledge, 2013. http://uknowledge.uky.edu/mng_etds/9.
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Froth flotation is the most commonly used process to recover and upgrade the portion of the coal preparation plant feed that has a particle size smaller than 150 microns. Problems that occur when employing froth flotation in the coal industry include i) coal surfaces that are weakly-to-moderately hydrophobic, and ii) flotation systems that are overloaded and limited by insufficient retention time.
Research was performed to evaluate techniques that could be implemented to improve flotation performance under the aforementioned scenarios. Pre-aeration of flotation feed using a cavitation system was extensively evaluated in laboratory and full-scale test programs. The benefits of adding hydrophobic, magnetic plastic particles were also investigated to improve froth stability and increase bubble surface area.
Laboratory tests revealed that pre-aeration through a cavitation tube improved coal recovery by as much as 20 absolute percentage points in both conventional cells and flotation columns when treating difficult-to-float coals. Carrying capacity increased by 32% which was projected to provide a 4 t/h increase in flotation recovery for a typical 4-m diameter flotation column. Product size analyses suggest that the improved particle recovery was more pronounced for the finest coal fractions as a result of particle agglomeration, resulting from the use of the nucleated air bubbles on the coal surfaces as a bridging medium. In-plant testing of a commercial-scale cavitation system found that feed pre-aeration could reduce collector dosage by 50% when no additional air is added and by 67% when a small amount of air is added to the feed to the cavitation system. At a constant collector dosage, recovery increased by 10 absolute percentage points with cavitation without additional air and 17 absolute points when additional air is provided.
The addition of hydrophobic plastic particles to the flotation feed at a 10% concentration by weight was found to substantially improve froth stability thereby elevating the recovery and enhancing carrying-capacity. Test results showed that the primary flotation improvements were directly linked to the coarsest particle size fractions in the plastic material which supports the froth stability hypothesis. Combustible recovery was increased up to 10 percentage points while producing the desired concentrate quality.
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Barbar, Elisar Jamil. "Nuclear Magnetic Resonance Study of Antigen-Antibody Complexes, Including Sequence Specific Assignments and Structural Analysis of Neurophysin as an Antigen Model." PDXScholar, 1993. https://pdxscholar.library.pdx.edu/open_access_etds/1167.
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The interaction between molecules is essential in a wide range of biological processes. A detailed knowledge of these interactions is necessary for understanding these processes. Among the systems that involve important interactions is the immune system. NMR spectroscopy has a large number of spectral parameters that were used in this work to study antibody-antigen interactions. These same parameters were also used to begin a structural analysis of a medium-sized protein, neurophysin, that has important interactions with neurohormones, and served here as a model antigen. A set of ligands differing in size and charge was designed and used to probe the binding site of anti-phosphocholine antibodies. These ligands ranged from small organic species to medium sized proteins. Amino acids, peptides and proteins were homogeneously linked to phenyl phosphocholine and analyzed by NMR techniques. Transferred nuclear Overhauser effect measurements were used to determine the conformation of bound ligands. The conformational change observed in some ligands was explained as either due to the antibody selecting one conformation that already exists, or the antibody binding inducing a conformational change. Titration data and detailed NMR analysis showed a more rigid M3C65 antibody fragment upon binding. In summary, with eight examples of ligands and four examples of antibodies studied by NMR, a spectrum of effects was seen, including a lock-and-key model and limited local induced fit. The contribution of the carrier molecule to antibody binding was in restricting the conformation of the ligand. Bigger ligands that are expected to be more immunogenic, showed less binding avidity as determined by immunological assays. Fluorinated ligands were synthesized to determine the kinetics of binding using 19F NMR spectra. Higher concentration of a fragment of the antibody M3C65 was analyzed to determine assignments of some residues in the combining site of the antibody. High resolution NMR techniques were used to assign resonances in neurophysin. The physiological role of neurophysin includes hormone storage and stabilization of oxytocin and vasopressin against proteolytic degradation within the posterior pituitary. Neurophysin is a 10 KD protein that dimerizes at high concentrations needed for NMR studies. An organic cosolvent was used to lower the dimerization constant, and hence inrease the spectral resolution. This permitted sequence-specific assignments that were then used to identify residues in the neurophysin-hormone binding site. Chemical shift differences and conformational changes were observed for the residues glutamate 47 and leucine 50. The 3₁₀ helix was further stabilized towards a more ideal helix upon hormone-analog peptide binding. Some of the residues contributing to the monomer-monomer interface were also assigned. Dimerization ill1duced chemical shift differences and conformational changes were observed for phenylalanine 35, threonine 38, and alanine 69. Tyrosine: 49 and phenylalanine 22 were affected but to a lesser extent. One characteristic of neurophysin in all studied cases was dynamic equilibrium between different folding states.
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Craig, Samantha L. "Rubidium Oscillator Error Model for Specific Force and Magnetic Field Susceptibility." Ohio University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1398126124.
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Al, Anazi Abdulaziz H. "Synthesis of Recyclable Magnetic Metal-ferrite Nanoparticles for the Removal of Contaminants of Emerging Concern in Water." University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1543922143864275.
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Evans, Gianna. "Ice Margin And Sediment Fluctuations Recorded In The Varve Stratigraphy Of Lake Ojibway." University of Cincinnati / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1326828319.
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Brubaker, Christopher John. "A Multimodal Magnetic Resonance Study of the Effects of Childhood Lead Exposure on Adult Brain Structure." University of Cincinnati / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1248964743.
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Hu, Yuguan. "A magnetic approach to the establishment of sediment-sourced linkages for reconstructing the Late Pleistocene and Holocene environmental evolution of the Lac d'Annecy, France." Thesis, University of Liverpool, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367193.
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East, Jackie R. "NATURAL PHENOMENA AS POTENTIAL INFLUENCE ON SOCIAL AND POLITICAL BEHAVIOR: THE EARTH’S MAGNETIC FIELD." UKnowledge, 2014. http://uknowledge.uky.edu/polysci_etds/11.
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Researchers use natural phenomena in a number of disciplines to help explain human behavioral outcomes. Research regarding the potential effects of magnetic fields on animal and human behavior indicates that fields could influence outcomes of interest to social scientists. Tests so far have been limited in scope. This work is a preliminary evaluation of whether the earth’s magnetic field influences human behavior it examines the baseline relationship exhibited between geomagnetic readings and a host of social and political outcomes. The emphasis on breadth of topical coverage in these statistical trials, rather than on depth of development for any one model, means that evidence is only suggestive – but geomagnetic readings frequently covary with social and political variables in a fashion that seems inexplicable in the absence of a causal relationship. The pattern often holds up in more-elaborate statistical models. Analysis provides compelling evidence that geomagnetic variables furnish valuable information to models. Many researchers are already aware of potential causal mechanisms that link human behavior to geomagnetic levels and this evidence provides a compelling case for continuing to develop the line of research with in-depth, focused analysis.
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Montague, James. "Assessing The Probability Of Fluid Migration Caused By Hydraulic Fracturing; And Investigating Flow And Transport In Porous Media Using Mri." ScholarWorks @ UVM, 2017. http://scholarworks.uvm.edu/graddis/793.
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Hydraulic fracturing is used to extract oil and natural gas from low permeability formations. The potential of fluids migrating from depth through adjacent wellbores and through the production wellbore was investigated using statistical modeling and predic-tive classifiers. The probability of a hydraulic fracturing well becoming hydraulically connected to an adjacent well in the Marcellus shale of New York was determined to be between 0.00% and 3.45% at the time of the study. This means that the chance of an in-duced fracture from hydraulic fracturing intersecting an existing well is highly dependent on the area of increased permeability caused by fracturing. The chance of intersecting an existing well does not mean that fluid will flow upwards; for upward migration to occur, a pathway must exist and a pressure gradient is required to drive flow, with the exception of gas flow caused by buoyancy. Predictive classifiers were employed on a dataset of wells in Alberta Canada to identify well characteristics most associated to fluid migration along the production well. The models, specifically a random forest, were able to identify pathways better than random guessing with 78% of wells in the data set identified cor-rectly.
Magnetic resonance imaging (MRI) was used to visualize and quantify contami-nant transport in a soil column using a full body scanner. T1 quantification was used to determine the concentration of a contaminant surrogate in the form of Magnevist, an MRI contrast agent. Imaging showed a strong impact from density driven convection when the density difference between the two fluids was small (0.3%). MRI also identified a buildup of contrast agent concentration at the interface between a low permeability ground silica and higher permeability AFS 50-70 testing sand when density driven con-vection was eliminated.
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Takatalo, J. (Jani). "Degenerative findings on MRI of the lumbar spine:prevalence, environmental determinants and association with low back symptoms." Doctoral thesis, Oulun yliopisto, 2015. http://urn.fi/urn:isbn:9789526207834.
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Abstract Earlier studies on lumbar degenerative imaging findings in magnetic resonance imaging (MRI) have been done mainly in adult populations and the associations of degenerative findings with low back pain (LBP) are controversial. Only a few studies have involved adolescents and young adults. Heritability has been acknowledged as the only explicit risk factor of disc degeneration (DD). This study investigated the prevalence and environmental determinant of lumbar degenerative findings in MRI and their association with low back symptoms among young adults. The data were based on two physical assessments, three questionnaires and one lumbar MRI that were executed on members of the Oulu Back Study (n=558), a subsample of Northern Finland Birth Cohort 1986, between 16 and 21 years of age. Prevalences of lumbar DD (54%), bulging (25%), protrusion (18%) and Schmorl’s node (17%) were high, whereas other degenerative findings were rare among young adults. Males had higher prevalence of DD and Schmorl’s nodes than females. DD and herniations were associated with low back symptoms. On the other hand, symptoms were present among subjects without DD or other abnormal findings on MRI. Of the environmental determinants, high body mass index and MRI-based obesity measurements of visceral adiposity were associated with lumbar DD among males. Waist circumference and smoking showed a comparable association with DD among males, but the level of physical activity was not associated with DD in either gender. Low back symptoms are more common among young adults with a higher degree of DD or presence of disc herniation. Smoking and overweight are associated with lumbar DD among young male adultsTiivistelmä Aikaisempia tutkimuksia magneettikuvantamisella (MK) todetuista lannerangan rappeumamuutoksista ja niiden yhteyksistä alaselkäkipuun on tehty lähinnä aikuisväestöllä ja tulokset ovat ristiriitaisia. Vain muutamia tutkimuksia on tehty alle 25-vuotiailla. Välilevyrappeuman mahdollisista riskitekijöistä vain perimästä on vahvaa näyttöä. Tässä tutkimuksessa tarkasteltiin MK:lla todettujen lannerangan rappeumamuutosten esiintyvyyttä, niihin vaikuttavia ympäristötekijöitä ja yhteyttä alaselkäoireisiin nuorilla aikuisilla. Tutkimuksen aineisto perustui kahteen kliiniseen tutkimukseen, kolmeen kyselyyn ja yhteen MK:een, jotka toteutettiin Pohjois-Suomen syntymäkohortti 1986:een kuuluville Oulun selkätutkimuksen koehenkilöille (n=558) 16-21 vuoden iässä. Lannerangan välilevyrappeumalla (54 %), välilevyn pullotuksilla (bulge; 25 %), sellaisilla välilevyn pullistumilla jotka eivät läpäisseet selkärangan takimmaista pitkittäissidettä (protruusio; 18 %) sekä päätelevyn läpi suuntautuvilla välilevyn pullistumilla (Schmorlin keräset; 17 %) oli korkea esiintyvyys nuorilla aikuisilla, kun taas muut kuvantamislöydökset olivat harvinaisia. Välilevyrappeuma ja Schmorlin keräset olivat yleisempiä miehillä. Sekä välilevyrappeuma että pullistumat olivat yhteydessä alaselkäoireisiin molemmilla sukupuolilla, mutta kaikilla oireisilla ei todettu poikkeavia löydöksiä MK:ssa. Ympäristötekijöistä korkea kehon painoindeksi ja MK:sta mitatut rasvan määrää mittaavat muuttujat olivat miehillä yhteydessä välilevyrappeumaan. Miehillä vyötärönympärys ja tupakointi olivat heikommin yhteydessä välilevyrappeumaan, kun taas liikunta-aktiivisuus ei ollut kummallakaan sukupuolella yhteydessä rappeumaan. Alaselkäoireet ovat yleisempiä nuorilla aikuisilla, joilla on vaikea-asteisempi välilevyrappeuma tai välilevyn pullistuma. Tupakointi ja ylipaino ovat yhteydessä lannerangan välilevyrappeumaan nuorilla aikuisilla miehillä
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Tingdal, Love. "Investigating the Magnetic Susceptibility of Cornish Loess as a Tool for Understanding the Palaeoclimate of SW England." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-417794.
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Loess is a silty material produced via glacial grinding and its deposition is usually associated with colder periods when there is a considerable increase in atmospheric dust transport. The magnetic susceptibility of loess-palaeosol sequences has been the subject of extensive research within palaeoclimatology as it has proven to be reliable climate proxy. Most research on magnetic susceptibility has been focused on thick deposits found in Europe and Asia, in particular the Chinese Loess Plateau where it is possible to discern more than 2.5 million years of climate variation in deposits several hundred meters thick. The climate development throughout the Quaternary has been characterized by glacials where there has been a significant ice growth, and interglacials where ice sheets have retreated. The Last Glacial Maximum was the most recent time of ice sheets reaching their maximum extent, occurring at some point between 26.5 and 18 ka BP. Aeolian reworking of material produced in conjunction with the Irish Sea Ice Stream (ISIS) occurred approximately 5000 years after the LGM. The ISIS limit were located just north of the Lizard Peninsula, and impinged on the Isles of Scilly. Loess deposits in SW England has largely been ignored in previous research in favour of the previously mentioned Chinese loess, but may be important climate archives in understanding the climate development of the North Atlantic. As such, the scope of this thesis is investigating the magnetic susceptibility of loess deposits in Cornwall and the Isles of Scilly in the far SW England. This is done by analyzing 36 samples from Lowland Point and 24 samples from Chynhalls Point, both located at the Lizard Peninsula in Cornwall, as well as 20 samples from Porthcressa and 14 samples from Gimble Porth, both located at the Isles of Scilly. The instruments used for analysis are the Bartington MS2B and the Agico MFK-1 FA Kappabridge, where all 96 samples were analyzed on the former while the 36 Lowland Points samples and the 20 Porthcressa samples were also analyzed on the latter. The Bartington MS2B operates at two frequencies, 465 Hz and 4650 Hz, while the Agico MFK-1 FA Kappabridge operates at three frequencies, 976 hz, 3904 Hz, and 15616 Hz. The results from this study suggest that the Lizard Peninsula sample sites exhibit signs of magnetic enhancement through pedogenic processes while the sample sites at the Isles of Scilly consist of mainly unaltered material, likely due to an overlying sollifluction unit inhibiting magnetic enhancement. As a consequence of the different frequencies, the results were lognormalized to permit a direct comparison between the instruments. While the variability in magnetic susceptibility was strikingly similar, the results of the Kappabridge were shifted to ~20% higher values than those of the Bartington which may be attributed to the Kappabridges higher precision when analyzing weakly magnetic material. A similar shift is not evident when measuring the calibration samples of each instrument. In determining the mean annual precipitation after deposition, the Lizard Peninsula samples sites suggest an exposure to an annual precipitation between 300-400 mm/yr, compared to modern rainfall between 900-1000 mm/yr. The data from the Isles of Scilly were insufficient for calculating the mean annual precipitation due to the lack of evidence for magnetic enhancement.Loess är benämningen för material i siltstorlek som produceras då glacial aktivitet maler ned den underliggande berggrunden. Detta material är tillräckligt litet för att fångas upp av vindar och därefter transporteras i atmosfären, för att därefter avsättas då vindhastigheten minskar. Under kalla perioder i jordens historia ökar denna transport då vindhastigheten ofta varit högre än under varma perioder. Under de varmare perioderna och med tiden så utsätts loess för jordmånsbildande processer och bildar palaeosoler. Den magnetiska susceptibiliteten hos loess-palaeosol-sekvenser har under flera årtionden varit ämnet för utbredd forskning då detta har visat sig vara en tillförlitlig klimatproxy för att förstå klimatutvecklingen under jordens gångna historia. I synnerhet har loess-palaeosol-sekvenser i Kina varit av intresse då det går att utröna mer än 2,5 miljoner år av klimatutveckling i avlagringar som på sina platser är flera hundra meter tjocka. Under den senaste istidens maximala utbredning mellan 26500 och 18000 år sedan passerade en isström över den Irländska sjön (Irish Sea Ice Stream, sammankopplad med inlandsisen), förbi Cornwalls norra kust och stötte samman med Scillyöarna. Det tog sedan ungefär 5000 år tills vindtransport av avsatt material påbörjades. Loessavlagringar i sydvästra England har känts till under årtionden men har till stor del ignorerats till fördel för de tidigare nämnda avlagringarna i Kina, men de kan agera som viktiga klimatarkiv för tiden efter den senaste istiden och därmed klimatutvecklingen i Nordatlanten. Denna rapport undersöker således den magnetiska susceptibiliteten i loess från två platser på Lizard-halvön i Cornwall, och två platser på Scillyöarna. Totalt analyserades 96 prover, 36 av dem från Lowland Point, 24 av dem från Chynhalls Point, båda belägna på Lizard-halvön, samt 20 prover från Porthcressa och 14 prover från Gimble Porth, båda belägna på Scillyöarna. Resultaten från denna studie påvisar att provplatserna på Lizard-halvön visar tecken på magnetisk förstärkning på grund av jordmånsbildande processer, medan provplatserna på Scillyöarna huvudsakligen består av oförändrat material, troligen på grund av att dessa täckts av annat material under isens tillbakadragning, vilket förhindrat jordmånsbildning. Resultaten från Lizard-halvön möjliggör beräkning av årsmedelnederbörden sedan materialet först avsattes, vilket beräknades till mellan 300-400 mm/år jämfört med modern årsmedelnederbörd mellan 900-1000 mm/år. Dessvärre möjliggjorde inte resultaten från provplatserna på Scillyöarna en liknande beräkning.
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Mai, Trang. "FUNCTIONALIZATION OF IRON OXIDE NANOPARTICLES AND THE IMPACT ON SURFACE REACTIVE OXYGEN SPECIES GENERATION FOR POTENTIAL BIOMEDICAL AND ENVIRONMENTAL APPLICATIONS." UKnowledge, 2019. https://uknowledge.uky.edu/cme_etds/102.
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Iron oxide nanoparticles (IONPs) have been widely studied for a variety of applications, from biomedical applications (e.g., cell separation, drug delivery, contrast agent for magnetic resonance imaging and magnetically mediated energy delivery for cancer treatment) to environmental remediations (e.g., heavy metal removal and organic pollutants degradation). It has been demonstrated that IONPs can induce the production of reactive oxygen species (ROS) via Fenton/Haber-Weiss reactions which has been shown to be one of the key underlying mechanisms of nanoparticles toxicity. This inherent toxicity of nanoparticles has been shown to enhance the efficacy of traditional cancer therapies such as chemotherapy and radiation. In addition, the generation of ROS induced by IONPs has been also studied as advanced oxidation processes (AOP) for wastewater treatment. Recent research has also shown that exposure to an alternating magnetic field can significantly enhance the generation of ROS induced by IONPs. Moreover, the coatings of IONPs play an important role on the surface reactivity of nanoparticles since it can prevent the generation of ROS via Fenton chemistries at the surface of the nanoparticles.
In this work, co-precipitated IONPs were functionalized with small molecules including citric acid, sodium phosphate, amino silane and dopamine. The impact of coating on surface reactivity of the as-synthesized particles was studied using methylene blue dye degradation assay under AMF exposure. With the coatings of these small molecules, the IONPs induced ROS generation was significantly decreased because of the dense surface coverage. To study the effect of polymeric coatings, a degradable poly (beta amino ester) (PBAE) polymer coating was synthesized with dopamine as an anchor to bind to nanoparticles. The surface reactivity of the particles was expected to be recovered once the polymer coating was degraded. Furthermore, the impact of non-degradable PEG-based polymer coating on surface reactivity via ROS generation was also investigated using methylene blue decolorization assay with the presence of AMF. The retention of surface reactivity of PEG-based polymer coated IONPs shows promise for cancer treatment.
The application of IONPs as heterogeneous catalyst for organic contaminant degradation was investigated. Bisphenol A (BPA) was used as a model compound, and Fenton reactions were induced by IONPs with the presence of hydrogen peroxide and hydroxylamine as well as alternating magnetic field exposure. The kinetics of BPA degradation under water bath and AMF exposure at 37oC was also studied, and the results showed potential applications of IONPs for organic pollutants remediation.
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Less, John Ryan. "Comparison of Natural Organic Matter (NOM) Removal Processes on Disinfection Byproduct (DBP) Formation During Drinking Water Treatment." University of Akron / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=akron1293217404.
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Andersson, Linus. "Sick of smells : Empirical findings and a theoretical framework for chemical intolerance." Doctoral thesis, Umeå universitet, Institutionen för psykologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-50569.
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Chemical intolerance (CI) is a term that refers to the surprisingly common phenomenon of persons getting ill from everyday chemicals. Although seemingly similar to asthma and allergies, CI sufferers do not react to exposures with increased histamine release. CI neither conforms to toxicological dose-response relationships as sufferers react to very low concentrations of chemicals assumed to be harmless. In addition, no particular chemical can be tied to any particular set of symptoms as in the case of other kinds of toxic injuries. The two overreaching goals of this thesis were to empirically investigate important hypotheses regarding CI, and to develop a theoretical framework that integrates previous theories of CI into a coherent whole.There are four empirical studies in this thesis. Utilizing event-related potentials (ERPs), magnitude estimations of perceived intensity, detection tests and functional magnetic resonance imaging (fMRI), the studies provided support for the following hypotheses: (1) persons with self-reported CI sensitize to olfactory and chemosomatosensory stimuli, whereas non-intolerant individuals habituate; (2) sensitization in CI is similar in terms of brain activation patterns to both non-clinical sensitization and other unexplained illnesses such as fibromyalgia; (3) persons with CI have an attention bias to chemical exposures, reflected by problems with withdrawing attention from such stimuli; (4) measures of peripheral hyperreactivity are correlated with chemosensory ERP measures; but failed to corroborate (5) the reactions of women resemble those found in persons with CI to a greater degree than the case in men.Three major theories of CI are also discussed. The neural sensitization theory describes CI as pathological and non-immunological increases in neural responsiveness. The conditioning theory describes CI as the result of basic associative learning mechanisms. The neurogenic inflammation theory describes CI as proliferation of sensory c-fibers and inflammatory responses carried to several parts of the body through axon reflexes and release of inflammatory mediators. The main point of the theoretical synthesis is that the theories offer different and complementary perspectives on CI, rather than presenting conflicting ontologies. With an integrated perspective, infected debates whether CI is a psychological or organic illness can hopefully be avoided.Finally, the unexplained characteristics of CI, the empirical findings and the theoretical accounts are described within the theoretical framework of signal detection theory. Several features of CI, e.g. sensitization and peripheral hyperreactivity, are described in terms of applying a low criterion (ß).Kemisk intolerans, det vill säga att få symtom av vardagliga lukter, är ett förvånansvärt vanligt problem. Trots att åkomman i många avseenden liknar astma och allergi, reagerar de drabbade inte med exempelvis ökad histaminfrisättning. Kemisk intolerans överensstämmer inte heller med toxikologiska dos-responsförhållanden, eftersom de drabbade blir sjuka av väldigt låga koncentrationer av luktämnen. Enskilda kemikalier kan inte kopplas till en karaktäristisk symtombild, vilket är vanligt vid andra typer av toxikologiska skador. I denna avhandling har jag två mål. För det första undersöker jag viktiga hypoteser om kemisk intolerans. För det andra erbjuder jag ett teoretiskt ramverk där jag integrerar tidigare teorier om kemisk intolerans till en sammanhängande helhet.Den empiriska delen av avhandlingen består av fyra forskningsstudier. Baserat på händelserelaterade hjärnpotentialer (ERPs), magnitudestimationer av upplevd styrka, detektionstest samt funktionell magnetresonansavbildning (fMRI) stöder studierna följande hypoteser: (1) personer med självrapporterad kemisk intolerans sensitiserar till olfaktoriska och kemosomatosensoriska stimuli, medan icke-intoleranta individer habituerar; (2) med avseende på hjärnaktiveringsmönster liknar sensitisering hos kemiskt intoleranta det mönster man finner både i icke-klinisk sensitisering och i exempelvis fibromyalgi; (3) personer med kemisk intolerans har en benägenhet att uppmärksamma kemisk exponering, vilket reflekteras i en oförmåga att ignorera sådana stimuli; (4) mått på perifer hyperreaktivitet korrelerar med kemosensoriska ERP-mått. Hypotesen att (5) kvinnors reaktioner på kemosensoriska stimuli liknar de man kan finna hos de kemiskt intoleranta i större utsträckning än vad fallet är för män, stöds däremot inte.Tre teorier om kemisk intolerans diskuteras. Den neurala sensitiseringsteorin beskriver intoleransen som en patologisk ökning av neural aktivitet. Betingningsteorin beskriver kemisk intolerans som ett resultat av grundläggande associativa inlägningsmekanismer. Slutligen beskriver teorin om neurogen inflammation intoleransen som en förhöjd aktivering av c-fiberaktivitet och ökade inflammatoriska processer. Huvudargumentet i den teoretiska sammanfattningen är att dessa teorier erbjuder komplementära perspektiv på kemisk intolerans. Med ett integrerat perspektiv kan förhoppningsvis infekterade debatter om huruvida kemisk intolerans är en psykologisk eller organisk åkomma undvikas.De oförklarade egenskaperna av kemisk intolerans, de empiriska fynden, samt de teoretiska förklaringarna beskrivs slutligen inom ett teoretiskt ramverk som utgår från signaldetektionsteorin. Flera egenskaper hos kemisk intolerans beskrivs i termer av ett förändrat eller lågt satt kriterium (ß).
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Gilljam, Päärt Oscar. "Petrophysic of the Host-rock to the Ore in the Lovisa Mine, Bergslagen." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-354796.
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The Bergslagen region has three base-metal mines operating today, and one of them is the Lovisa mine, which host a Zn-Pb-Ag deposit. The Lovisa mine is located in the Guldsmedshyttan area north of Lindesberg. The mine is part of in the X-Mine H2020 project that includes four different mines with the aim of an improved environmental resource management. The project aims at reducing the environmental impact from transport, ore processing and chemical handling as well as result in lowering the costs per produced amount of metal. The purpose for this thesis is to determine the petrophysical characteristics of the host rocks to the thin tabular mineralised units in the Lovisa mine with petrophysics. Petrophysics is used to obtain information about the physical properties of rocks, which is then is integrated with geophysics and the geology, to obtain an improved understanding about the different geophysical anomalies. The petrophysic methods used here, reviled three different physical properties of the rocks: density, magnetic volume susceptibility and natural remanent magnetization. These properties were measured on five different drill cores and correlated with the literature data and lithologies of the core. The lithologies close to the ore correspond to literature data for volcanic siltstone, volcanic sandstone, massive rhyolite, skarn (calc-silicates) and dolomite. Dolomite is not present in the cores and corresponds to breccia, volcanic sandstone and skarn. My conclusion for this method, is that in order to do a lithological interpretation based on the measured petrophysical properties, is that a good knowledge of the lithologies as well as a good understanding of the geological processes that have affected the rocks in the investigated area are required.I Bergslagen finns det idag tre aktiva gruvor som bryter sulfidmalm, och en av dem är Lovisagruva som är en malmkropp Zn-Pb-(Ag)-malm. Lovisagruvan ligger i Guldsmedshytteområdet, norr om Lindesberg. Gruvan är en del av X-Mine-projektet som bl.a. undersöker små, komplexa malmkroppar i syfte att reducera miljöpåverkan och effektivisera produktionen. Syftet med detta kandidatarbete är att bestämma petrofysiska egenskaper hos lithologin i det malmnära sidoberget vid Lovisagruva. Petrofysik används för att ta reda på bergets fysikaliska egenskaper, och dessa egenskaper används sedan inom geofysik, för att få en förståelse för de olika avvikelser som visas i andra geofysiska mätningar. De petrofysiska mätningarna som utfördes, gav tre fysikaliska egenskaper hos varje prov, densitet, magnetisk susceptibilitet och den naturliga magnetiska remanensen. Resultaten från varje prov korrelerades sedan med litteraturdata och jämfördes med borrkärneloggar från Lovisa. De petrofysiska mätningarna utfördes på prover från fem olika borrhål. Resultatet visar att det malmnära sidoberget korrelerar med litteraturdata på vulkanisk siltsten, vulkanisk sandsten, kalksilikat, ryolit, skarn och dolomit. Dolomit finns inte i kärnorna utan representeras av bl.a. breccia, vulkanisk sandsten och skarn. Min slutsats är att det går att bestämma lithologin med dessa fysikaliska egenskaper, men man måste ha en god kännedom om vilka bergarter som förväntas att förekomma i området samt vilka geologiska processer som påverkat dem.
H2020 X-mine
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Linderholm, Johan. "The soil as a source material in archaeology. : Theoretical considerations and pragmatic applications." Doctoral thesis, Umeå universitet, Institutionen för idé- och samhällsstudier, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-31380.
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This thesis deals with questions on various applications using soils and sediments as sources of information in archaeological research. Human environmental impact on soils and sediments, in terms of pollution, is a well known phenomenon as the industrialisation intensified during historical times and onwards and has left strong pollutive marks. However, humans have always accumulated or emitted matter and various compounds in connection to their habitats for subsistence, but these earlier traces are not always detectable, depending on soil and sediment state of preservation. Bioessential elements are intimately linked to humans and their dwellings and especially phosphate has been evident in this respect. It was established already in the 1930s, that even Stone Age settlements could be located through elevated phosphate content in extensive soil phosphate mappings. This thesis is a compilation on results from several sites and excavations from the southern to the northern parts of Sweden. There is a wide variety of soil types and chronological setting in the material, from highly acid podzols to calcareous soils, and sediments dated to Younger Dryas to current top soils. Sites from the Mesolithic, Neolithic, Bronze Age, Early and Late Iron Age and Medieval are all represented. Methods that have been implemented are firstly various forms of analysis in regards to soil phosphate, magnetic susceptibility and organic matter. Furthermore, metal and non-metal elements have been considered, as well as lead isotopes. A multiproxy approach is applied in some examples where biological and chemical data is combined to interpret past events. In this thesis there are also five papers presented. The first paper deals with methodological issues concerning multi-element analyses of various soil samples (off-site to feature) from an archaeological excavation. The second paper is about the possibilities that may be used when analysing the soil organic phosphate in relation to prehistoric agriculture. Paper three and fourth are compilations of large scale contract archaeological project. These papers deal with theoretical, methodological and practical issues concerning environmental archaeology in relation to contract archaeology. Studies on landscape development and erosion are among the cases presented. The last paper deals with a late Mesolithic - early Neolithic settlement in Vuollerim, N. Sweden, and spatial dimensions on the human use of settlement (off-site to on-site) and house floors (intra-site), are discussed.
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Sulaiman, Ali Haidar. "The near-Saturn magnetic field environment." Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/44209.
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Shock waves exist throughout the universe and are fundamental to understanding the nature of collisionless plasmas. The complex coupling between charged particles and electromagnetic fields in plasmas give rise to a whole host of mechanisms for dissipation and heating across shock waves, particularly at high Mach numbers. While ongoing studies have investigated these process extensively both theoretically and via simulations, their observations remain few and far between. This thesis presents a study of very high Mach number shocks in a parameter space that has been poorly explored and identifies reformation using in situ magnetic field observations from the Cassini spacecraft at Saturn's bow shock. This gives an insight into quasi-perpendicular shocks across two orders of magnitude in Alfvén Mach number (MA) and spanning Earth-like to Astrophysical-like regimes. The work here shows evidence for cyclic reformation controlled by specular ion reflection occurring at the predicted timescale of ~0.3 τc, where τc is the ion gyroperiod. The relationship between these reformation signatures, magnetic overshoot and variability are also presented. The final part of this thesis characterises the region downstream of Saturn's bow shock, the magnetosheath. The results show a comprehensive overview of the configuration of the magnetic field in a non-axisymmetric magnetosheath. This non-axisymmetry is revealed to have an impact in the rotation of the magnetic field and is significant enough to influence the magnetic shear at the magnetopause.