Дисертації з теми "Polar Science"
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Riddolls, Ryan James 1974. "Structure of the polar electrojet antenna." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/16945.
Повний текст джерелаIncludes bibliographical references (p. 153-156).
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Field experiments were performed in Gakona, Alaska in August and November 2002. The ionospheric conductivity was periodically perturbed using amplitude-modulated radiation from the HAARP HF transmitter (1 MW power, 14 dB gain, 3.3-5.8 MHz carrier, 0.1-40 kHz modulation). The conductivity perturbations lead to perturbations to the natural flow of electrojet current in the lower ionosphere, resulting in ELF/VLF radiation at the modulation frequency. Measurements of the radiation, along with analytic and numerical models, suggest that a vertical loop with a scale size of 10 km is the dominant current structure excited during the experiments.
by Ryan James Riddolls.
Ph.D.
Ba, Demba Elimane. "Nonlinear transform coding with lossless polar coordinates." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/37937.
Повний текст джерелаIncludes bibliographical references (p. 51-52).
In conventional transform coding, the importance of preserving desirable quantization partition cell shapes prevents one from considering the use of a nonlinear change of variables. If no linear transformation of a given source would yield independent components, this means having to encode it at a rate higher than its entropy, i.e. suboptimally. This thesis proposes a new transform coding technique where the source samples are first uniformly scalar quantized and then transformed with an integer-to-integer approximation to a nonlinear transformation that would give independent components. In particular, we design a family of integer-to-integer approximations to the Cartesian-to-polar transformation and analyze its behavior for high rate transform coding. Among the benefits of such an approach is the ability to achieve redundancy reduction beyond decorrelation without limitation to orthogonal linear transformations of the original variables. A high resolution analysis is given, and for source models inspired by a sensor network application and by image compression, simulations show improvements over conventional transform coding. A comparison to state-of-the-art entropy-coded polar quantization techniques is also provided.
by Demba Elimane Ba.
S.M.
Schild, Ingrid. "The politics of international collaboration in Polar research." Doctoral thesis, University of Sussex, 1996. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-42850.
Повний текст джерелаJin, Menglin. "Interpolation of surface radiative temperature measured from polar orbiting satellites to a diurnal cycle." Diss., The University of Arizona, 1999. http://hdl.handle.net/10150/282883.
Повний текст джерелаWalsh, Stephen Anthony. "Between the Arctic & the Adriatic: Polar Exploration, Science & Empire in the Habsburg Monarchy." Thesis, Harvard University, 2014. http://nrs.harvard.edu/urn-3:HUL.InstRepos:13070045.
Повний текст джерелаHistory
Davis, Jason Michael. "Reconsidering Antarctic Bioprospecting through Territorialities of Science, Property, and Governance." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1299535648.
Повний текст джерелаBecerra, Patricio, and Patricio Becerra. "The Poles of Mars, Past and Present: A High-Resolution Observational Study of the Martian Polar Regions and their Connection to Climate." Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/621066.
Повний текст джерелаMancini, Duane Joseph. "Large Scale Synthesis of Amphiphiles for Biological Use and Analytical Profile of Polar Extracts from Mastic Gum." University of Toledo Health Science Campus / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=mco1404224303.
Повний текст джерелаOkunev, Oleg. "Observations and modeling of polar faculae on the sun." Doctoral thesis, [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=975320157.
Повний текст джерелаFinnie, Sean McIlwain. "Wheat polar lipids : sources of variation among near-isogenic wheat lines with different endosperm hardness." Diss., Manhattan, Kan. : Kansas State University, 2009. http://hdl.handle.net/2097/1384.
Повний текст джерелаJones, Megan E. "Sixty Years of Widespread Warming in the Southern Mid- and High-Latitudes (1957-2016)." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1525542816174135.
Повний текст джерелаBonev, Boncho Peichev. "Towards a chemical toxonomy of comets : infrared spectroscopic methods for quantitative measurements of cometary water (with an independent chapter on Mars polar science) /." See Full Text at OhioLINK ETD Center (Requires Adobe Acrobat Reader for viewing), 2005. http://www.ohiolink.edu/etd/view.cgi?toledo1133980701.
Повний текст джерелаTypescript. "A dissertation [submitted] as partial fulfillment of the requirements of the Doctor of Philosophy degree in Physics." Includes bibliographical references (leaves 295-304).
Bonev, Boncho P. "Towards a Chemical Taxonomy of Comets: Infrared Spectroscopic Methods for Quantitative Measurements of Cometary Water (With an Independent Chapter on Mars Polar Science)." University of Toledo / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1133980701.
Повний текст джерелаZhou, Albert Lihong. "Bioactivities of Milk Polar Lipids in Influencing Intestinal Barrier Integrity, Systemic Inflammation, and Lipid Metabolism." DigitalCommons@USU, 2013. http://digitalcommons.usu.edu/etd/1517.
Повний текст джерелаSeibel, Harry Andrew II. "Psuedo-Oxides: Property Tailoring Through the Integration of Nitrogen and Fluorine." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1250624527.
Повний текст джерелаPopendorf, Kimberly J. (Kimberly Julia). "Marine microbial intact polar diacylglycerolipids and their application in the study of nutrient stress and bacterial production." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/79293.
Повний текст джерела"February 2013." Cataloged from PDF version of thesis.
Includes bibliographical references.
Intact polar diacylglycerolipids (IP-DAGs) were used to study microbial dynamics in the surface ocean. IP-DAGs from surface ocean seawater were quantified using high performance liquid chromatography-mass spectrometry (HPLC-MS), after first developing a sensitive, high throughput molecular ion independent triple quadrupole MS method for quantification. Using this analytical technique I examined the distribution of the nine most abundant classes of IPDAGs across the Mediterranean, and found that phospholipids as a percent of total IP-DAGs correlated with phosphate concentration. Furthermore, phospholipids were a higher percent of total particulate phosphorus where phosphate was higher, ranging from 1-14%. Thus IP-DAGs can play not only a significant but also a dynamic role in defining planktonic nutrient needs and cellular C:N:P ratios in the environment. Additionally, microcosm incubations were amended with phosphate and ammonium, and in the course of several days this elicited a shift in the ratios of IP-DAGs. This study was the first to demonstrate the dynamic response of membrane lipid composition to changes in nutrients in a natural, mixed planktonic community, and indicated that the change in IP-DAG ratios in response to changing nutrients may be a useful indicator of microbial nutrient stress. In the surface waters of the western North Atlantic I used three experimental approaches to identify the microbial sources of the nine most abundant classes of IP-DAGs. Phytoplankton are the primary source of one class of sulfolipid, sulfoquinovosyldiacylglycerol, and one class of betaine lipid, diacylglyceryl-trimethyl-homoserine, while heterotrophic bacteria are the dominant source of the phospholipids phosphatidylglycerol and phosphatidylethanolamine. In regrowth experiments in the Sargasso Sea and the North Pacific I demonstrated that phospholipid specific production rate is representative of heterotrophic bacterial cell specific growth rate. I measured phospholipid specific production rate and bacterial production rate using uptake of 3H-leucine (³H-Leu) and 3H-thymidine (³H-TdR) across the North Atlantic, across the Mediterranean, and in the North Pacific subtropical gyre. I found that phospholipid specific production rates estimate heterotrophic bacterial cell specific growth rates that are on the order of 1 per day, an order of magnitude faster than cell specific growth rates suggested by uptake of ³H-Leu and ³H-TdR.
by Kimberly J. Popendorf.
Ph.D.
Suciu, Loredana G. "Indirect Determination of Integrated Chlorine and Bromine Concentration from Hydrocarbons in Barrow, Alaska." Ohio University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1179950576.
Повний текст джерелаHenri, Dominique. "Managing nature, producing cultures : Inuit participation, science and policy in wildlife governance in the Nunavut Territory, Canada." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:2cde7bcb-4818-4f61-9562-179b4ee74fee.
Повний текст джерелаTulip, David F. "Preservice primary teachers' constructions of themselves as science teachers." Thesis, Queensland University of Technology, 1999. https://eprints.qut.edu.au/36598/1/36598_Digitised%20Thesis.pdf.
Повний текст джерелаNath, de Oliveira Daniela. "Thermal properties of starch from transgenic isolines of wheat differing in starch surface components." Thesis, Kansas State University, 2010. http://hdl.handle.net/2097/4319.
Повний текст джерелаDepartment of Grain Science and Industry
Jon M. Faubion
Endosperm texture is an important characteristic in determining wheat processing and end-use. The presence of puroindoline proteins on the starch surface is the biochemical marker for wheat hardness. Near-isogenic samples over expressing puroindolines have been used to assess the effect of wheat hardness on final product characteristics. The objective of this study was to determine differences among starch isolated from near-isogenic samples and to investigate the role starch surface components play in pasting. The use of near-isogenic samples over expressing puroindolines combined with the use of two methods of starch isolation (batter and dough) was an effective means to create samples with varied amounts of surface components. Starch thermal properties were characterized and surface proteins and lipids were quantified. Starch isolated from hard wheat cultivars presented more similarities with starch isolated from its soft near-isogenic line when a dough method was used than when a batter method was used. Starch from soft experimental lines isolated using a batter method showed increased MVA peak viscosity, breakdown and swelling power. Increased levels of LysoPC in starch isolated from hard wheat cultivars or soft experimental lines by dough method could have complexed with amylose and restricted granule swelling. Thereby, decreasing peak viscosity, breakdown and swelling power.
Haines, Wesley Adam. "Acceleration of the Weather Research & Forecasting (WRF) Model using OpenACC and Case Study of the August 2012 Great Arctic Cyclone." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1373472482.
Повний текст джерелаSmith, Erik T. "HISTORICAL AND FUTURE CHANGES IN COLD AIR OUTBREAKS ACROSS THE GLOBE AND THE INFLUENCE OF ATMOSPHERIC TELECONNECTIONS." Kent State University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=kent1615739656563986.
Повний текст джерелаCheng, Jian. "Estimation and Processing of Ensemble Average Propagator and Its Features in Diffusion MRI." Phd thesis, Université Nice Sophia Antipolis, 2012. http://tel.archives-ouvertes.fr/tel-00759048.
Повний текст джерелаSmith, Erik T. "The Characteristics of Cold Air Outbreaks in the eastern United States and the influence of Atmospheric Circulation Patterns." Kent State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=kent1499870942487366.
Повний текст джерелаSeal, Gavin J. "Morphisms of polar spaces and related structures." Doctoral thesis, Universite Libre de Bruxelles, 2000. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/211809.
Повний текст джерелаAshraf, Hina. "Investigation of the Symmetries of the Phonons in 4H and 6H-SiC by Infrared Absorption and Raman Spectroscopy." Thesis, Linköping University, The Department of Physics, Chemistry and Biology, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-6079.
Повний текст джерелаThe goal of the project work has been to study the symmetry of the phonons in 4H and 6H-SiC for different measuring geometries by using two experimental techniques, Raman and infrared absorption (IR) spectroscopy, and a theoretical model. The Raman spectra were measured in different scattering configurations in order to obtain experimental data for detailed investigation of the phonon symmetries.
The gross features of the spectra obtained in different geometries can be explained using general group-theoretical arguments. Using a lattice-dynamics model, we have also calculated the angular dependence of the phonon energies near the centre of the Brillouin zone, as well as the phonon displacements in some high-symmetry directions. The theoretical results are used to interpret the Raman lines in different configurations, and it was possible to estimate that if ionicity of the bonding of 12% is taken in the theoretical model for 4H-SiC, the splitting of the polar TO mode and the shift of the polar LO mode observed in our spectra are well reproduced theoretically. It was also observed that these polar modes have to be classified as longitudinal and transversal with respect to the direction of phonon wave vector, while the rest of the modes remain longitudinal or transversal with respect to the c-axis of the crystal. The Raman lines in the case of 4H SiC have been tentatively labelled with the irreducible representations of the point group of the crystal (C6v).
O'Neill, Morgan E. "A theory for polar cyclones on giant planets." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/97335.
Повний текст джерелаCataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 135-145).
features, with a deep, hot and rapid cyclone situated directly over each pole, and a rapid jet marking the cyclone boundary at 3° from the pole. Extant theories for the zonal jets preclude the possibility of a jet at such high latitudes. This thesis proposes and tests a moist convective hypothesis for polar cyclone formation. Using purely baroclinic forcing, with statistical characteristics motivated by moist convection observed on Jupiter and Saturn, a robust tendency to form a barotropic polar cyclone is identified. A 2 1/2 layer shallow water model is built to test our hypothesis. An 11-dimensional parameter space is explored to determine the most importance controls on cyclone formation. Two sets of experiments are performed: 1) Barotropic and baroclinic 'storms' are briefly forced and then allowed to freely evolve on the polar beta plane, and 2) Forced-dissipative simulations are run, with periodic and randomly placed storms, until statistical equilibrium is reached. Results confirm the well known tendency of positive vorticity anomalies to self-advect poleward if they are intense enough for nonlinear advection to be significant. Likewise, strong negative vorticity anomalies move equatorward. Simulations span several orders of magnitude of energy density, ranging from weak wave-dominated flows to strong cyclones that experience instabilities. We find that a range of behavior, including what is observed on all four giant planets as well as previous simulation studies, can be expressed by varying only 2 nondimensional control parameters: a second baroclinic deformation radius scaled by the planetary radius, LD2=a; and a total energy parameter Êp that scales with the kinetic+potential energy density of the system at statistical equilibrium. In the context of an idealized model, the difference between Jupiter's and Saturn's polar flow regimes may be explained by their different planetary and deformation radii.
by Morgan E. O'Neill.
Ph. D.
Tarnoff, David. "Episode 3.11 – Polar and Bipolar Line Coding." Digital Commons @ East Tennessee State University, 2020. https://dc.etsu.edu/computer-organization-design-oer/27.
Повний текст джерелаRosenqvist, Tobias, and Joël Sloof. "Implementation and evaluation of Polar Codes in 5G." Thesis, Karlstads universitet, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-72467.
Повний текст джерелаAchtert, Peggy. "Lidar Measurements of Polar Stratospheric Clouds in the Arctic." Doctoral thesis, Stockholms universitet, Meteorologiska institutionen (MISU), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-88054.
Повний текст джерелаAt the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 2: Submitted.
Zhang, Hengfang. "Hot-wall MOCVD of N-polar group-III nitride materials." Licentiate thesis, Linköpings universitet, Halvledarmaterial, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-175502.
Повний текст джерелаAdditional funding agencies: Chalmers University of technology; ABB; Ericsson; Epiluvac; FMV; Gotmic; Saab; SweGaN; UMS; Swedish Foundation for Strategic Research under Grants No. FL12-0181, No. RIF14-055, and No. EM16-0024; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linköping University, Faculty Grant SFO Mat LiU No.2009- 00971.
Arrell, Russell 1975. "Implications of Martian polar insolation levels on the climatic cycling of volatiles." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/53045.
Повний текст джерелаIncludes bibliographical references (leaves 35-36).
Solar insolation at the poles is the driving force in Mars' seasonal climatic cycle. Mars' obliquity has varied greatly in the geologically recent past and this would have had a profound effect on the past climate. Previous studies have always assumed a spherical planet when calculating insolation. This study uses a geodetic elevation model (GEM) of the elevation data from the Mars Orbiter Laser Altimeter, to provide accurate insolation calculations. This method takes into account the long and shortwavelength topography, the planetary curvature, and the planetary flattening. This paper outlines the design and implementation of a GEM, and presents insolation calculations for Mar's north polar cap for obliquities of 150, 250 and 450. This study found that the elevation of the northern ice cap above the surroundings results in the ice cap having more days of sunlight than previously thought.
by Russell Arrell.
S.M.
Evaratt, Matthew. "Stress ecophysiology of polar terrestrial invertebrates and the impact of climate change." Thesis, University of Birmingham, 2014. http://etheses.bham.ac.uk//id/eprint/5020/.
Повний текст джерелаBiddle, M. B., S. E. Rickert, J. B. Lando, and André Laschewsky. "The use of the Langmuir-Blodgett technique to obtain ultra-thin polar films." Universität Potsdam, 1989. http://opus.kobv.de/ubp/volltexte/2009/1718/.
Повний текст джерелаCarron, Delphine. "Figures du détective dans le polar américain contemporain." Phd thesis, Université d'Angers, 2013. http://tel.archives-ouvertes.fr/tel-00961471.
Повний текст джерелаSheshadri, Aditi. "Variability of the polar stratospheric vortex and its impact on surface climate patterns." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/98674.
Повний текст джерелаCataloged from PDF version of thesis. "June 2015."
Includes bibliographical references (pages 133-145).
This thesis investigates various aspects of the variability of the stratospheric polar vortex and the effect of this variability on tropospheric weather and climate patterns on various timescales. In the first part of this work, an improved idealized model was developed to study the coupled stratosphere-troposphere system. The model is forced by relaxation to a specified equilibrium temperature profile, which varies seasonally only in the stratosphere. This model setup permits the investigation of stratosphere-troposphere interactions on seasonal timescales, without the complication of an internal tropospheric seasonal cycle. The model is forced with different shapes and amplitudes of simple bottom topography, resulting in a range of stratospheric climates. The effect of these different kinds of topography on the seasonal variability of the strength of the polar vortex, the average timing and variability in timing of the final breakup of the vortex (final warming events), the conditions of occurrence and frequency of midwinter warming events, and the impact of the stratospheric seasonal cycle on the troposphere are explored. The inclusion of wavenumber 1 and wavenumber 2 topographies results in very different stratospheric seasonal variability. Hemispheric differences in stratospheric seasonal variability are recovered in the model with appropriate choices of wave-2 topography. In the model experiment with a realistic Northern Hemisphere-like frequency of midwinter warming events, the distribution of the intervals between these events suggest that the model has no year to year memory. When forced with wave-1 topography, the gross features of seasonal variability are similar to those forced with wave-2 topography, but the dependence on forcing magnitude is weaker. Further, the frequency of major warming events has a non-monotonic dependence on forcing magnitude, and never reaches the frequency observed in the northern hemisphere. In the second part of the thesis, the impact of stratospheric ozone depletion on the Antarctic polar vortex and its subsequent influences on southern hemisphere surface climate patterns is investigated. It is verified that stratospheric final warming events have an impact on tropospheric circulation in a simplified GCM with seasonal variations in the stratosphere only. The model produces qualitatively realistic final warming events whose influence extends down to the surface, much like what has been reported in observational analyses. The hypothesis that recent observed trends in surface westerlies in the Southern Hemisphere are directly consequent on observed trends in the timing of stratospheric final warming events is tested. It is confirmed that there is a statistically significant shift towards later final warming events in the years with large ozone depletion. However it is found that the observed trends in surface westerlies cannot be attributed simply to this shift towards later final warming events. Finally, responses of the idealized AGCM to polar stratospheric cooling that mimics the radiative effects of stratospheric ozone depletion are studied. It is found that there are two factors that play a role in setting the magnitude and persistence of the model's surface response to cooling: the seasonal cycle of tropospheric annular mode timescales, and whether or not the imposed cooling leads to the presence of stratospheric westerlies at a time when easterlies were prevalent in the control run. That is, the surface response is sensitive to the timing of the imposed polar stratospheric cooling.
by Aditi Sheshadri.
Ph. D.
Smirnova, Maria. "Long-term observations of polar mesosphere summer echoes using the ESRAD MST radar." Doctoral thesis, Luleå tekniska universitet, Rymdteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-18134.
Повний текст джерелаGodkänd; 2011; 20110926 (marsmi); DISPUTATION Ämnesområde: Rymdteknik/Space Technology Opponent: Professor Patrick Joseph Espy, Dep of Physics, Norwegian University of Science and Technology (NTNU), Trondheim, Norway, Ordförande: Docent Evgenia Belova, Swedish Institute of Spaces Physics, Kiruna Tid: Måndag den 31 oktober 2011, kl 10.00 Plats: Aulan, Swedish Institute of Spaces Physics, Kiruna
Greenberg, Marc Samuel. "Defining Benthic Organism Exposure: Bioavailability and Effects of Non-Polar Organics." Wright State University / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=wright1074096654.
Повний текст джерелаHarris, Carolyn Louise. "Water mass distribution and Polar Front structure in the Southwestern Barents Sea." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/54421.
Повний текст джерелаIncludes bibliographic references (leaves 63-66). Includes bibliographical references (leaves 63-66).
by Carolyn Louise Harris.
M.S.
Mount, Christopher P. "Spatial, temporal, and inter-annual variability of the Martian northern seasonal polar cap." Thesis, Northern Arizona University, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=1537795.
Повний текст джерелаEarth and Mars have nearly the same axial tilt, so seasons on these two bodies progress in a similar manner. During fall and winter on Mars, the primarily CO2 atmosphere (~95% by volume) condenses out onto the poles as ice. Approximately 25% of the entire Martian atmosphere condenses, and then sublimes in the spring, making this cycle a dominant driver in the global climate. Because the water and dust cycles are coupled to this CO2 cycle, we must examine seasonal CO2 processes to understand the global (seasonal) distribution of H2O on Mars. The density of the ice may indicate whether it condensed in the atmosphere and precipitated as “snow” or condensed directly onto the surface as “slab”. Variations in density may be controlled by geographic location and surface morphology. The distribution and variations in densities of seasonal deposits on the Martian poles gives us insight to the planet’s volatile inventories. Here we analyze density variations over time on Mars’ Northern Polar Seasonal Cap (NPSC) using observational data and energy balance techniques.
We calculate the bulk density of surface CO2 ice by dividing the column mass abundance (the mass of CO2 per unit area) by the depth of the ice cap at a given location. We use seasonal rock shadow measurements from High Resolution Imaging Science Experiment (HiRISE) images to estimate ice depth. The length of a rock’s shadow is related to its height through the solar incidence angle and the slope of the ground.
From differences in the height of a rock measured in icy vs. ice-free images, we estimate the depth of surface ice at the time of the icy observation. Averaging over many rocks in a region yields the ice depth for that region. This technique yields minimums for ice depth and therefore maximums for density.
Thermal properties of rocks may play an important role in observed ice depths. Crowns of ice may form on the tops of rocks with insufficient heat capacity to inhibit ice condensation, and may cause an artificial increase in shadow length. This increases the apparent height of a rock and thus decreases the apparent surface ice depth. Additionally, moats may form around rocks with sufficient heat capacity to sublime ice as it is deposited. Moating will also artificially increase the shadow lengths (decreasing apparent surface ice depth). We correct for these effects in our depth-estimation technique.
We balance incoming solar flux with outgoing thermal radiation from Thermal Emission Spectrometer (TES) observations to calculate the column mass abundance. TES thermal bolometer atmospheric albedo and temperature observations are a good proxy to the surface bond albedo and effective surface temperature. These parameters are needed to balance the incoming and outgoing flux.
Mars’ atmosphere is tenuous so we assume homogeneous radiance from the surface to the top of the atmosphere, no lateral diffusion of heat, and that any excess heat goes into subliming surface ice in our flux balance. Using a Monte Carlo model, we integrate the net flux until reaching the time where Cap Recession Observations indicate CO2 has Ultimately Sublimed (the CROCUS date) to obtain the column mass abundance.
We study seasonal ice at three distinct geomorphic units: plains, dune fields, and craters. Two plains regions, four dunes regions, and two crater regions are analyzed over springtime sublimation. Data for these regions spanned three Mars Years.
Our results indicate that the evolution of seasonally deposited CO 2 ice on the Northern Polar Cap of Mars is highly dependent on complex relationships between various processes. The grain size, dust contamination, water doping, and density vary dramatically over time. The initially deposited material varies according to local geomorphic features and topography, as well as latitude and longitude. The inter-annual variability of ice may play a role in its evolution over sublimation, but likely plays a smaller role than anticipated. Low normalized initial and time-averaged densities suggest that NPSC deposits are initially low and remain relatively low throughout spring. These densities are very similar to estimates made by previous studies. Thus, we conclude that the NPSC is indeed pervaded by low density deposits. These deposits densify over time, but rarely reach typical characteristics for pure slab ice.
Jones, Matthew. "The social construction of a threatened species: a critical analysis of a polar bear discourse." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=97131.
Повний текст джерелаDans cette thèse, je réalise une analyse de discours critique concernant le débat de l'ours polaire; plus précisément, le discours du Centre de la Diversité Biologique sera analysé. Une vulgarisation de ce discours sera faite en en adressant deux questions clef : Comment est construit ce discours en forme textuelle? Quelles sont les pratiques discursives principales et quelles sont leurs contextes socioculturels qui supportent ces textes? Les résultats de mon analyse démontrent que le discours de l'ours polaire du Centre de la Diversité Biologique est construit de multiples facettes qui sont liées par des pratiques discursives et socioculturelles. Ces pratiques sont eux même attachées à quatre éléments: scientifiques, étiques, politiques et métaphoriques. Cette découverte est potentiellement utile pour des acteurs qui on moins de pouvoir décisive dans ce débat, comme les communautés Inuit, puisque de nouvelles voies peuvent être créées en critiquant les positions dominantes et en exprimant leur propre.
Patil, Ravikant Amogisidha. "Production of acetic acid in kraft pulp mill biorefinery using bi-polar membrane electrodialysis." Thesis, The University of Maine, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10300301.
Повний текст джерелаThe objective of this dissertation was to develop a process for the production of acetic acid in kraft mills. Acetyl groups in hardwood can be hydrolyzed using alkali at 50 °C. The product from this process contains about 15 g/L of sodium acetate and was determined to be suitable for the production of acetic acid.
Experiments performed using aqueous sodium acetate to evaluate the ability of electrodialysis (ED) to separate and concentrate sodium acetate showed that sodium acetate can be concentrated up to 275 g/L starting with an initial concentration of 17 g/L. The transport of water with sodium and acetate ions through ED membranes limited the maximum obtainable concentration.
To avoid the deleterious effects of white liquor on ED, selectivity experiments were performed using synthetic oxidized white liquor extract. These experiments showed a decrease in the efficiency of ED process due to the presence of sodium carbonate and sodium sulphate in the extract. Hence, it was concluded that caustic should be used as the extraction solvent.
Bi-polar electrodialysis (BPMED) experiments performed using sodium acetate showed that up to 200-280 g/L of acetic acid can be produced using BPMED. Although higher concentrations of sodium hydroxide can also be produced using BPMED, 30 g/L concentration was considered to be sufficient for recycle to the extraction process.
Feed and bleed mode BPMED experiments were performed to determine the current efficiencies and the suitable inlet concentration of sodium acetate for the production of up to 200 g/L of acetic acid. Both feed and bleed mode and batch experiments showed that the current density was the major driving force for BPMED.
Two types of concentrated wood extracts; namely (1) clarified and (2) unclarified were prepared with and without the lignin removal pre-treatment, respectively. The results of the ED and BPMED experiments performed using these extracts were similar to those of the synthetic sodium acetate. A major difference involved an increase of about 15% in electric energy consumption arising from the transport of formate, lactate and glycolate salts. The color of the anionic membranes slightly changed after processing unclarified extract through ED and BPMED.
Norin, Gustav. "Development of UPLC-MS/MS method for the determination of polar metabolites." Thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-69074.
Повний текст джерелаSaxin, Jonathan. "Jämförelse av Polar Vantage V ”Konditionstest” med direkt mätning av VO2max." Thesis, Linnéuniversitetet, Institutionen för idrottsvetenskap (ID), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-104215.
Повний текст джерелаBackground: There are several models of fitness devices on the market with functions that claims to have the capability to estimate the capacity of a individuals maximum oxygen uptake. One of these models is the Polar Vantage V fitness watch, which according to the manufacturer can estimate the VO2max through the function "Fitness test". The test is performed through a five-minute rest test. The test result is then calculated thru various variables such as the individuals resting heart rate and personal factors. Purpose: To assess the estimated test value of the Polar Vantage V “Fitness test” with a direct measurement of VO2max, with the research question whether this test was valid and useful in practice. Method: This study used an experimental design and included 11 men and 5 women as participants (N = 16). All participantsfirst performed the Polar Vantage V's “Fitness test”, then proceeded to perform a maximum performance using a treadmill. For measurement of VO2max, the cardiopulmonary exercisetesting system Jaeger®Vyntus CPX with half mask was used. Results: Kendall Tau-b test presented a significant strong positive relationship between Vantage V’s “Fitness test” and VO2max -value from the Vyntus CPX. The Wilcoxon Signed Rank test presented a nonsignificant difference between the test value (group mean value) from Vantage V “Fitness test”and VO2max from Vyntus CPX. Conclusion: Due to large individual differences in the test value measured by the "Fitness test" from Vantage V, one should interpret the test-result with care. However, the Vantage V "Fitness test" seems to be able to provide a good estimate of theVO2max at group level in healthy adults aged between 20-36.
Dowsley, Martha. "The development of multi-level governance for the management of polar bears in Nunavut Territory, Canada." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=18694.
Повний текст джерелаCette thèse compare le système socio-écologique, impliquant la gestion des ours polaire du Nunavut, et la conversion d'un système de gestion directionel (« top-down ») vers un système de gouvernance multi-niveaux . Les interactions des échelles de gouvernance avec les éléments biophysiques, économiques et socio-culturelles sont abordées, en mettant l'accent sur les échelles locales. La co-gestion, comme méthode de gouvernance, est également examinée afin d'évaluer l'incorporation des idéologies Euro-Canadiennes et Inuits en ce qui concerne les ours polaires. Notre hypothèse de recherche stipule stipulant que les Inuits gagnent du pouvoir par l'acquisition d'une autorité accordée par la co-gestion. Toutefois, nos recherches n'ont pas corroboré l'hypothèse voulant que les individus chassant l'ours polaire et les autres Inuits impliqués dans le système formel de gouvernement adopteraient les idéologies Euro-Canadienne, en raison de l'influence du pouvoir du marché économique et historique présent dans le système de gestion directionnel. Au contraire, les Inuits utilisent les outils scientifiques Euro-Canadiens et l'économie de marché, mais résistent aux idées de gestion directive et la commercialisation des ours polaires dans l'économie de marché. La compréhension traditionelle des relations entre les Hommes, entre les Hommes et les ours polaires sur l'économie sociale de substistance a été utilisée afin d'opposer les idées Euro-Canadiennes de la co-gestion et pour rationaliser l'utilisation de l'ours polaire pour des raisons économiques.
Tewelde, Yodit. "Constraining the average fill densities of Mars' lowlands and fluvial erosion of Titan's polar regions." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/84910.
Повний текст джерелаCataloged from PDF version of thesis.
Includes bibliographical references (pages 67-78).
Other than Earth, Mars and Titan are the only bodies in our Solar System where we have observed widespread fluvial activity. In this thesis I present two approaches for constraining the extent of multiple resurfacing processes in order to gain insight into the early history of Mars and Titan. One of the most distinctive features of the Martian surface is the dichotomy between the heavily cratered southern highlands and the relatively smooth northern lowlands. The northern lowlands appear smooth because many of the craters in the north have been partially or completely buried beneath volcanic and sedimentary fill of unknown relative proportions. In Chapter 1, we use the Mars Orbiter Laser Altimeter (MOLA) topography data, the Mars Reconnaissance Orbiter (MRO) gravity model and a Wiener filter to map these buried craters and estimate minimum fill thickness and volume as well as maximum fill density. The overall trend observed for the northern lowlands is more sedimentation near the dichotomy and less sedimentation further north and near the Tharsis region, which is consistent with the geology of the region. Titan has few impact craters, suggesting that its surface is geologically young. In Chapter 2 we evaluate whether fluvial erosion has caused significant resurfacing by estimating the cumulative erosion around the margins of polar lakes. Images of drowned fluvial features around the lake margins, where elevated levels of hydrocarbon liquids appear to have partly flooded fluvial valleys, allow us to map topographic contours that trace the fluvially dissected topography. We then used a numerical landscape evolution model to calibrate a relationship between contour sinuosity, which reflects the extent of fluvial valley incision, and cumulative erosion. We find that cumulative fluvial erosion around the margins of Titan's polar lakes, including Ligeia Mare, Kraken Mare, and Punga Mare in the north and Ontario Lacus in the south, ranges from 4% to 31% of the initial relief. Additional model simulations show that this amount of fluvial erosion does not render craters invisible at the resolution of currently available imagery, suggesting that fluvial erosion is not the only major resurfacing mechanism operating in Titan's polar regions.
by Yodit Tewelde.
S.M.in Planetary Science
Baucher, Marie. "Modification of lignin quality in transgenic poplar and alfalfa." Doctoral thesis, Universite Libre de Bruxelles, 1996. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/212365.
Повний текст джерелаEgekwu, Chioma. "Influence of nitrogen and sink competition on shoot growth of poplar." Thesis, University of Maryland, College Park, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10130093.
Повний текст джерелаTerrestrial and oceanic biomass carbon sinks help reduce anthropogenic CO2 emissions and mitigate the long-term effect of increasing atmospheric CO2. Woody plants have large carbon pools because of their long residence time, however N availability can negatively impact tree responses to elevated CO2. Seasonal cycling of internal N in trees is a component that contributes to fitness especially in N limited environments. It involves resorption from senescing leaves of deciduous trees and storage as vegetative storage proteins (VSP) in perennial organs. Populus is a model organism for tree biology that efficiently recycles N. Bark storage proteins (BSP) are the most abundant VSP that serves as seasonal N reserves. Here I show how poplar growth is influenced by N availability and how growth is influenced by shoot competition for stored N reserves. I also provide data that indicates that auxin mediates BSP catabolism during renewed shoot growth. Understanding the components of N accumulation, remobilization and utilization can provide insights leading to increasing N use efficiency (NUE) of perennial plants.
Chard, Julie K. "Uptake and Transformation of Trichloroethylene by Hybrid Poplar: Laboratory Studies." DigitalCommons@USU, 1999. https://digitalcommons.usu.edu/etd/3647.
Повний текст джерелаLabrecque, Jeremy. "Indicator species of soil nutrients and poplar plantation productivity in southeastern Quebec." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66757.
Повний текст джерелаDeux sites de plantations situés approximativement 60 kilomètres l'un de l'autre ont été étudiés afin de déterminer quels nutriments était les plus limitants et de comparer la variance à l'échelle de 3-9m (microsite) à la variance à l'échelle de 100-1000m. Un site était 20% plus productif que l'autre avec un taux de croissane de 6.9 m3 ha-1 dans ça cinquième année. L'analyse de la composante principale a dévoilé que aucun des nutriments n'était limitant tandis qu'à l'autre site le N et la K parassait être limitants. La variance à l'échelle 3-9m semble être au moins aussi importante que la variance à l'échelle 100-1000m dans son explication des mesures de productivité, dans la majorité des cas. Le potentiel de problèmes rencontrés dans l'échelle de variation des microsites peut être expliqué en se servant d'une analyse d'espèces indicatrices. L'analyse de la fonction de distribution empirique a révèlé que certaines espèces présentes dans les plantations de peupliers hybrides (e.g. Fragaria spp. et Polytrichum spp.) pourraient être de bons indicateurs de sites à productivité élevé ou basse.