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Wu, Xiaohua. "Field simulation and calibration in external electro-optic sampling." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ30181.pdf.
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Wu, Xiaohua. "Field simulation and calibration in external electro-optic sampling /." *McMaster only, 1996.
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Diehl, J. W., S. E. Naranjo, and P. C. Ellsworth. "Whitefly Growth Regulators: A Field Sampling Protocal for Nymphs." College of Agriculture, University of Arizona (Tucson, AZ), 1997. http://hdl.handle.net/10150/211111.
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We developed a sampling protocol for nymphs of the sweetpotato whitefly for timing the application of insect growth regulators. These plans require counting the number of large, visible nymphs within a 3.88 cm² leaf disk on the fifth main stem node leaf down from the terminal. Use of insect growth regulators for whitefly control is recommended when whitefly densities from 30 plants average 0.5 - 1.0 large nymphs per disk and 3 - 5 adults per leaf. We evaluated these sampling and decision- making plans within a large -scale field experiment. Precision was adequate for densities of 1.0 large nymph per leaf and greater, but sample sizes greater than 30 are needed for lower densities. The ability of samplers to detect and categorize nymphal instars and sampler-to-sampler variation in this ability were significant sources of variation. A binomial (presence/absence) sampling plan may diminish sampler-sampler variation while increasing efficiency and accuracy of decision- making.
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Gil, Ley Alejandro. "Enhanced sampling and force field corrections for RNA oligomers." Doctoral thesis, SISSA, 2016. http://hdl.handle.net/20.500.11767/4628.
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The computational study of conformational transitions in nucleic acids still faces many challenges. For example, in the case of single stranded RNA tetranucleotides, agreement between simulations and experiments is not satisfactory due to inaccuracies in the force fields commonly used in molecular dynamics. Improvement of force fields is however hindered by the diiculties of decoupling those errors from the statistical errors caused by insuicient sampling. We here tackle both problems by introducing a novel enhancing sampling method and using experimental data to improve RNA force fields. In this novel method, concurrent well-tempered metadynamics are integrated in a Hamiltonian replica-exchange scheme. The ladder of replicas is built with different strength of the bias potential exploiting the tunability of well-tempered metadynamics. Using this method, free-energy barriers associated to individual collective variables are significantly reduced compared with simple force-field scaling. The introduced methodology is flexible and allows adaptive bias potentials to be self-consistently constructed for a large number of simple collective variables, such as distances and dihedral angles. Additionally, a modified metadynamics algorithm is used to calculate correcting potentials designed to enforce distributions of backbone torsion angles taken from experimental structures. Replica-exchange simulations of tetranucleotides including these correcting potentials show significantly better agreement with independent solution experiments for the oligonucleotides containing pyrimidine bases. Although the proposed corrections do not seem to be portable to generic RNA systems, the simulations reveal the importance of the α and ζ backbone angles for the modulation of the RNA conformational ensemble. The correction protocol presented here suggests a systematic procedure for force-field refinement.
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Wei, Jian. "Microcolumn field sampling and flow injection techniques for mercury speciation." Thesis, Sheffield Hallam University, 1993. http://shura.shu.ac.uk/20513/.
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Mercury is one of the most toxic heavy metals, and many serious incidents have resulted from mercury poisoning. The methylation of mercury and its amplification by marine life have aggravated this pollution problem. Studies over the last three decades have shown that the toxicity of mercury is related to chemical form. A basic aim of the research has been to devise new methodology for the measurement and speciation of mercury. Key points of the investigation reported were the literature review of methodologies and techniques for mercury speciation and the development of a novel manifold which incorporates microcolumns of sulphydryl cotton which have a relatively high affinity and selectivity for inorganic and / or organomercury, and to utilise a continuous flow procedure for mercury speciation based on flow injection-atomic fluorescence spectrometry. This new and novel system has been used for the determination and speciation of mercury in a variety of water samples. The other column packing materials, eg. xanthate cotton, activated alumina and 8-hydroxy-quiniline were also investigated. A further aspect of element speciation concerns the development of a field sampling technique using sulphydryl cotton columns. Sample collection and preconcentration using microcolumns at the site of sampling was successfully performed. Preliminary experiments indicated that the field sampling technique in combination with FIA-AFS was a robust and potentially useful speciation tool. Field surveys on mercury distribution and speciation in the Manchester Ship Canal and the River Rother have been intensively carried out in collaboration with the National Rivers Authority (North West Region). The analytical data on different mercury species in waters of the Manchester Ship Canal are reported for the first time. A high correlation between organomercury and organolead in the Manchester Ship Canal is found and the related data have been assessed in order to clarify the possible origins for organomercury. Related work concerning participation in interlaboratory studies is reported in the Appendices.
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Abili, Nimi Inko. "Subsea fluid sampling to maximise production asset in offshore field development." Thesis, Cranfield University, 2015. http://dspace.lib.cranfield.ac.uk/handle/1826/10017.
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The acquisition of representative subsea fluid sampling from offshore field development asset is crucial for the correct evaluation of oil reserves and for the design of subsea production facilities. Due to rising operational expenditures, operators and manufacturers have been working hard to provide systems to enable cost effective subsea fluid sampling solutions. To achieve this, any system has to collect sufficient sample volumes to ensure statistically valid characterisation of the sampled fluids. In executing the research project, various subsea sampling methods used in the offshore industry were examined and ranked using multi criteria decision making; a solution using a remote operated vehicle was selected as the preferred method, to compliment the subsea multiphase flowmeter capability, used to provide well diagnostics to measure individual phases – oil, gas, and water. A mechanistic (compositional fluid tracking) model is employed, using the fluid properties that are equivalent to the production flow stream being measured, to predict reliable reservoir fluid characteristics on the subsea production system. This is applicable even under conditions where significant variations in the reservoir fluid composition occur in transient production operations. The model also adds value in the decision to employ subsea processing in managing water breakthrough as the field matures. This can be achieved through efficient processing of the fluid with separation and boosting delivered to the topside facilities or for water re-injection to the reservoir. The combination of multiphase flowmeter, remote operated vehicle deployed fluid sampling and the mechanistic model provides a balanced approach to reservoir performance monitoring. Therefore, regular and systematic field tailored application of subsea fluid sampling should provide detailed understanding on formation fluid, a basis for accurate prediction of reservoir fluid characteristic, to maximize well production in offshore field development.
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Morgan, Richard Brierley. "Field studies of atmospheric peroxides and the development of sampling methods." Thesis, University of Leeds, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.410964.
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Holmes, Colette Gail. "Field sampling and microcolumn preconcentration techniques in inductively coupled plasma spectrometry." Thesis, Sheffield Hallam University, 1996. http://shura.shu.ac.uk/19820/.
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This thesis is concerned with analytical studies on the trace analytes barium, cadmium, cobalt, chromium, copper, iron, manganese, nickel, lead, vanadium and zinc, present in high purity and highly complex matrices. The technique utilises activated alumina microcolumns in a flow injection (FI) system, to perform analyte enrichment and matrix removal. The analytes, after retention on the microcolumn are subsequently eluted and quantified by inductively coupled plasma-emission spectrometry (ICP-ES).Initial studies focus on trace analytes in caesium iodide, however a selection of the alkali metal salts, lithium nitrate, potassium bromide, sodium fluoride and sodium chloride, are investigated. New methodology for the ultratrace determination of high purity alkali metal salts is thus provided. The microcolumn enrichment technique with ICP-ES detection is robust, utilises limited sample handling and simultaneously preconcentrates and separates the analytes from matrix components. Hence possible matrix interferences are eliminated and limits of detection are significantly improved, in comparison to conventional ICP-ES analysis. A technique for the determination of the total content of eleven trace analytes present in natural waters (mineral, reservoir), using microcolumns of activated alumina in a FI-ICP-ES is investigated. The use of the complexing agent tartaric acid is shown to be effective in improving analyte retention. The procedure is successfully applied to determination of these analytes in a certified river water reference material (SLRS-1). Due to low retention and elution efficiencies, the total content of the analytes Fe and V present in Buxton, Redmires and Langsett samples could not be accurately determined by this technique. Activated alumina microcolumns are utilised as a new field sampling tools. Samples are collected in the field and processed through the alumina microcolumns for the effective retention of desired analytes. Hence, an alumina microcolumn sampling stage to effect concentration and isolation prior to analytical measurement is at the core of the investigation. The overall aim is to extend the application of alumina microcolumns, and in particular to provide a new multi-element field sampling device, which gives high sample integrity and preconcentration.
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Conner, Laura. "Evaluation of field sampling and analysis methods for fire investigation including electronic noses and adsorption sampling/gas chromatography mass spectrometry." FIU Digital Commons, 2005. http://digitalcommons.fiu.edu/etd/2422.
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This study evaluates the use of commercially available instruments for locating and collecting accelerants in the field. Electronic noses can be used to scan a fire scene for the possible presence of an accelerant. The TLV Sniffer® was found to be able to detect accelerants at low levels but did alert to some burned matrix alone. When subjected to a proficiency test designed for canines, the TLV Sniffer® was able to locate accelerants in two of the three tests. The tpi®Pocket was found not to be sensitive or selective enough to be useful in locating accelerants. Once the location of possible accelerants has been determined, they can be collected by dynamic headspace sampling in the field with the Portable Arson Sampler (PAS). The PAS was found to be able to collect a broad range of compounds from ignitable liquids and had comparable efficiency to a conventional method.
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Kaharabata, Samuel K. "Moisture transfer behind windbreaks : laboratory simulations and conditional sampling in the field." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60535.
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The spatial distribution of local evaporation from ground-based sources behind solid and porous windbreaks was studied in laboratory models for steady state and intermittent flows. Field observations of wind and turbulence characteristics (turbulence intensity, power spectra and integral length scale L) over surfaces whose zero displacement (d) and roughness length (z$ sb0$) had also been determined, were used to scale the laboratory simulations. Scaling parameters were z/z$ sb0$, $ sigma$/U, L/z$ sb0$ and Uz$ sb{0}$/K, where z, U, $ sigma$ and K are height, wind speed, standard deviation of velocity fluctuations and turbulent diffusivity, respectively. The 50% porosity barrier was found to be the most effective single-barrier set-up for the reduction of moisture loss.<br>Conditional sampling of fluctuations w' and q' of the wind and moisture, respectively, with sonic anemometer and fast-response Krypton hygrometer behind solid and porous windbreaks in the field, revealed frequency of occurrence, duration and intensity of those turbulent structures primarily responsible for moisture transfer.
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Morandage, Shehan [Verfasser]. "Characterization of Root System Architectures from Field Root Sampling Methods / Shehan Morandage." Bonn : Universitäts- und Landesbibliothek Bonn, 2020. http://d-nb.info/1221668927/34.
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Fernandez, Maria Luz Mena. "Field sampling and flow injection strategies for trace analysis and element speciation." Thesis, Sheffield Hallam University, 1997. http://shura.shu.ac.uk/19646/.
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Over the last two decades research has shown that the different forms of trace elements in the environment can cause a variety of health concerns as a result of differences in toxicity. The need to establish efficient, effective and reliable speciation methods has become paramount. A basic aim of this work has been to advance speciation measurement capability for key trace elements (mercury, lead and chromium) by devising an integrated analytical approach that links the sample collection, sample preservation and laboratory measurements in an unified manner. An introductory chapter first reviews the occurrence of organometallic compounds in the environment and focuses on the identification of the "environmental compartments" where transformations of such species can take place. Speciation studies also assist in understanding the biogeochemical cycling of trace elements. Moreover, a review of the various methodologies used for trace element speciation measurements including hyphenated techniques and/or a variety of chemical/physical pretreatments in combination with flow injection (FI) is discussed. Chapter 2 describes mercury speciation experiments utilising gas chromatography-microwave induced plasma-atomic emission spectrometry (GC-MIP-AES) and FI. The approach was based on the preconcentration of mercury on sulphydryl cotton and after elution from the microcolumn, separation and quantitation of methyl-, ethyl- and inorganic mercury species. Method development experiments were performed using a derivatisation technique which gave low contamination and allowed rapid analysis of samples. The microcolumn technique was transferred to the field and speciation of mercury in surface waters of the Manchester Ship Canal was undertaken and high methylmercury concentrations (0.052-0.182 ug 1 -1, as Hg) were detected. In so doing the new approach offered the preservation of the natural speciation state of the water sample directly at the sampling site and during the interval between collection and analysis. In chapter 3 lead studies are centred on the development of a rapid speciation scheme for neutral and cationic (organic and inorganic) lead species based on activated alumina microcolumn separation in combination with ICP-MS and FI. The approach permitted rapid assessment of the nature of lead contamination in environmental waters. Speciation of lead in surface waters of the Manchester Ship Canal was also undertaken using the field sampling approach in an attempt to confirm a transmethyllation reaction between organolead and inorganic mercury. A further application for microcolumns, in the context of speciation measurement, is their use as external calibrants and certified reference materials (CRMs) and this is discussed in the penultimate chapter. Key elements were mercury and chromium. After immobilisation of mercury species on SCF microcolumns it was found that recoveries for methyl- and inorganic mercury were quantitative over 4 months in contrast to ethylmercury which was 2 months. Similar studies for chromium species indicated ineffective elution and more vigorous conditions (microwave assisted digestion) for the elution step were used. A final chapter reviews progress and recommendations are given concerning future research and application for microcolumn field sampling in combination with instrumental analytical techniques.
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Murray, Jacolin Ann. "High Flow Air Sampling for Field Detection Using Gas Chromatography-Mass Spectrometry." BYU ScholarsArchive, 2010. https://scholarsarchive.byu.edu/etd/2414.
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The ability to rapidly detect and identify hazardous analytes in the field has become increasingly important. One of the most important analytical detection methods in the field is gas chromatography-mass spectrometry (GC-MS). In this work, a hand-portable GC-MS system is described that contains a miniature toroidal ion trap mass analyzer and a low thermal mass GC. The system is self-contained within the dimensions of 47 x 36 x 18 cm and weighs less than 13 kg. Because the instrument has a small footprint, it was used as the detector for an automated near-real-time permeation testing system. In permeation testing, materials that are used to make individual protective equipment such as gloves, masks, boots, and suits are exposed to hazardous analytes to determine how long the equipment can be worn safely. The system described herein could test five samples simultaneously. A multi-position valve rotated among the various sample streams and delivered time aliquots into the MS for quantitation. Current field air sampling techniques suffer from long desorption times, high pressure drops, artifact formation and water retention. These disadvantages can be avoided by concentrating the analytes in short open tubular traps containing thick films. There are several advantages to using polymer coated capillaries as traps, including fast desorption, inertness and low flow restriction. An air sampling trap was constructed utilizing open tubular traps for the concentration of semi-volatile organic compounds. The system consisted of multiple capillary traps bundled together, providing high sample flow rates. The analytes were desorbed from the multi-capillary bundle and refocused in a secondary trap. The simultaneous focusing and separation effect of a trap subjected to a negative temperature gradient was also explored. In this configuration, analytes were focused because the front of the peak was at a lower temperature than the rear of the peak and, hence, moved slower. In addition to the focusing effect, analytes with different volatilities focused at different temperatures within the gradient, allowing for separation.
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Litman, Jacob Mordechai. "Advanced optimization and sampling techniques for biomolecules using a polarizable force field." Diss., University of Iowa, 2019. https://ir.uiowa.edu/etd/6792.
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Biophysical simulation can be an excellent complement to experimental techniques, but there are unresolved practical constraints to simulation. While computers have continued to improve, the scale of systems we wish to study has continued to increase. This has driven the use of approximate energy functions (force fields), compensating for relatively short simulations via careful structure preparation and accelerated sampling techniques. To address structure preparation, we developed the many-body dead end elimination (MB-DEE) optimizer. We first proved the MB-DEE algorithm on a set of PCNA crystal structures, and accelerated it on GPUs to optimize 472 homology models of proteins implicated in inherited deafness. Advanced physics has been clearly demonstrated to help optimize structures, and with GPU acceleration, this becomes a possibility for large numbers of structures. We also show the novel “simultaneous bookending” algorithm, which is a new approach to indirect free energy (IFE) methods. These first perform simulations under a cheaper “reference” potential, then correct the thermodynamics to a more sophisticated “target” potential, combining the speed of the reference potential with the accuracy of the target potential. Simultaneous bookending is shown as a valid IFE approach, and methods to realize speedups vs. the direct path are discussed. Finally, we are developing the Monte Carlo Orthogonal Space Random Walk (MC-OSRW) algorithm for high-performance alchemical free energy simulations, bypassing some of the difficulty in OSRW methods. This work helps prevent inaccuracies caused by simpler electrostatic models by making advanced polarizable force fields more accessible for routine simulation.
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Piao, Dongzhen. "Speeding Up Gibbs Sampling in Probabilistic Optical Flow." Research Showcase @ CMU, 2014. http://repository.cmu.edu/dissertations/481.
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In today’s machine learning research, probabilistic graphical models are used extensively to model complicated systems with uncertainty, to help understanding of the problems, and to help inference and predict unknown events. For inference tasks, exact inference methods such as junction tree algorithms exist, but they suffer from exponential growth of cluster size and thus is not able to handle large and highly connected graphs. Approximate inference methods do not try to find exact probabilities, but rather give results that improve as algorithm runs. Gibbs sampling, as one of the approximate inference methods, has gained lots of traction and is used extensively in inference tasks, due to its ease of understanding and implementation. However, as problem size grows, even the faster algorithm needs a speed boost to meet application requirement. The number of variables in an application graphical model can range from tens of thousands to billions, depending on problem domain. The original sequential Gibbs sampling may not return satisfactory result in limited time. Thus, in this thesis, we investigate in ways to speed up Gibbs sampling. We will study ways to do better initialization, blocking variables to be sampled together, as well as using simulated annealing. These are the methods that modifies the algorithm itself. We will also investigate in ways to parallelize the algorithm. An algorithm is parallelizable if some steps do not depend on other steps, and we will find out such dependency in Gibbs sampling. We will discuss how the choice of different hardware and software architecture will affect the parallelization result. We will use optical flow problem as an example to demonstrate the various speed up methods we investigated. An optical flow method tries to find out the movements of small image patches between two images in a temporal sequence. We demonstrate how we can model it using probabilistic graphical model, and solve it using Gibbs sampling. The result of using sequential Gibbs sampling is demonstrated, with comparisons from using various speed up methods and other optical flow methods.
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Miki, Kenji. "Analysis of the influence of device-scale wind field on the sampling efficiency of pollen as a representative bioaerosol." Doctoral thesis, Kyoto University, 2020. http://hdl.handle.net/2433/253312.
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京都大学<br>0048<br>新制・課程博士<br>博士(農学)<br>甲第22476号<br>農博第2380号<br>新制||農||1074(附属図書館)<br>学位論文||R2||N5256(農学部図書室)<br>京都大学大学院農学研究科地域環境科学専攻<br>(主査)教授 中村 公人, 教授 星野 敏, 教授 藤原 正幸<br>学位規則第4条第1項該当<br>Doctor of Agricultural Science<br>Kyoto University<br>DFAM
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Hutchinson, Bill, Debra Stroschein, Bud Beasley, Jeanette Martin, and Tom Henneberry. "Field Evaluation of a Presence-Absence, Sequential Sampling Plan for Pink Bollworm Eggs." College of Agriculture, University of Arizona (Tucson, AZ), 1988. http://hdl.handle.net/10150/204502.
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During 1987, a sequential sampling plan for pink bollworm eggs was field-tested in eight 40-acre fields in the Palo Verde Valley, CA. Final analysis of the sequential procedure, including the time necessary to collect and check all bolls, required an average sampling time of 16 minutes/field, approximately a 70% savings over the fixed sample size of 160 bolls/field. Using the sequential plan, the number of bolls examined averaged 46.75/field. The sequential sampling plan error rate for making no-treat recommendations when a field actually required treatment (i.e., actual egg infestation 6%) averaged only 6.4% throughout the season. A final sequential sampling chart, based on the field validation data, is presented.
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Markthaler, Daniel [Verfasser], and Niels [Akademischer Betreuer] Hansen. "Disentangling force field and sampling issues in biomolecular systems / Daniel Markthaler ; Betreuer: Niels Hansen." Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2020. http://d-nb.info/1233737767/34.
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Jacobsen, Jannes. "Establishing a Survey of Refugees in Germany: Challenges in Sampling, Field Work and Measurement." Doctoral thesis, Humboldt-Universität zu Berlin, 2020. http://dx.doi.org/10.18452/21856.
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Diese Dissertation betrachtet verschiedene Schritte einer sozialwissenschaftlichen Erhebung zur Integration Geflüchteter in Deutschland. Anhand von vier Zeitschriftenartikeln wird eine neuartige Strategie, um eine Zufallsstichprobe von Geflüchteten in Deutschland zu ziehen, besprochen, die Folgen fehlender muttersprachlicher Übersetzungen von Fragebögen analysiert, latente Konstrukte auf Vergleichbarkeit getestet und Fragen ökonomischer Integration in sich verändernden Migrationsregimen diskutiert.
Der erste Artikel befasst sich mit einer sequentiellen Ziehungsstrategie für Zufallsstichproben. Diese ermöglicht eine zeitnahe Erhebung von Zuwanderern in Zeiten hoher Immigration, da Registerdaten Migranten nur mit zeitlicher Verzögerung umfassend abdecken.
Im zweiten Artikel wird gezeigt, dass fehlende muttersprachliche Übersetzungen von Umfragen die Item-Nonresponse erhöhen. Auch die Bereitstellung von Audio-Aufnahmen kann diesem Effekt nicht entgegenwirken.
Im dritten Artikel wird die Vergleichbarkeit latenter Konstrukte in multikulturellen und multisprachlichen Erhebungen am Beispiel von Vorstellungen zu demokratischen Systemen untersucht. Messinvarianztests deuten darauf hin, dass Vorstellungen von Demokratie über verschiedene Herkunftsländer und Sprachen nicht vergleichbar sind.
Der letzte Artikel beschäftigt sich mit der ökonomischen Integration Geflüchteter und argumentiert, dass diese auf institutioneller Ebene betrachtet werden muss. Fixed-Effects- Regressionsanalysen kombiniert mit einem exakten Matching führen zu der Schlussfolgerung, dass sichere Aufenthaltstitel und die Teilnahme an Integrationskursen bei Geflüchteten in Deutschland zu einer erhöhten Anstrengung führt Zugang zum Arbeitsmarkt zu bekommen.<br>This dissertation looks at the different steps in the process of conducting a survey on refugees living in Germany and discusses key focal points of integration research.
In four different articles, I discuss the novel sampling strategy used in a survey of refugees, analyze the effects of missing questionnaire languages, test latent constructs for measurement invariance, and discuss the analysis of economic integration in a changing migration regime.
In the first article, I propose a sequential sampling strategy to sample refugees in times of high immigration.
In the second article, I show that the lack of questionnaires in a respondent’s mother tongue increases item nonresponse. Providing additional audio recordings of the questions does not diminish this effect.
In the third article, I use conceptions of democracy as a case study to show that latent constructs in multi-cultural and multi-linguistic surveys face specific challenges and limitations in their comparability. By employing tests for measurement invariance, my results show that conceptions of democracy are likely not comparable across countries of origin or across languages.
The fourth and last article looks at the economic integration of refugees. In it, I propose that integration trajectories have to be observed within the specific institutional settings in which they take place. Fixed-effects regression analyses combined with a coarsened exact matching lead to the conclusion that a secure residence permit and participation in integration classes lead to increasing investments in future labor market access of refugees in Germany.
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Toland, Ashley Anne. "Post-release establishment and supercooling point assessment of Laricobius osakensis, a predator of the hemlock woolly adelgid." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/82712.
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The hemlock woolly adelgid (HWA), Adelges tsugae Annand (Hemiptera: Adelgidae), is an invasive pest from Japan that is causing significant hemlock mortality in the eastern U.S. The most promising control method is biological control. Beetles in the genus Laricobius are adelgid specialists. In 2005, Laricobius osakensis, was discovered in Japan and in 2010 was approved for release in the eastern United States and there have now been more than 60 releases. In 2014, the polar vortex resulted in significant HWA mortality in the eastern U.S., depleting the food source for L. osakensis, which resulted in low field recoveries of them. In the 2015-2016 field season, there were 14 larvae recovered from the field, and the 2016-2017 field season yielded 90 larvae. A significant correlation was found between Laricobius beetles recovered and HWA density, between HWA density and plant hardiness zone, and a negative correlation between Laricobius beetles recovered and average tree health. Understanding more about the supercooling point of L. osakensis gave insight to its ability to survive subfreezing temperatures as occurred in 2014. Comparison of the supercooling point between the northern and southern populations of L. osakensis, and to the other released HWA predator, L. nigrinus, will allow us to determine which biological control agent is best suited for release in the coldest regions. The overall mean supercooling points of northern L. osakensis was -13.52 oC, southern L. osakensis was -13.42 oC, and L. nigrinus was -13.57 oC. There were no significant differences between species or populations.<br>Master of Science in Life Sciences
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Jacobsen, Jannes [Verfasser]. "Establishing a Survey of Refugees in Germany: Challenges in Sampling, Field Work and Measurement / Jannes Jacobsen." Berlin : Humboldt-Universität zu Berlin, 2020. http://d-nb.info/1218073993/34.
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Remsen, Andrew Walker. "Evolution and field application of a plankton imaging system." [Tampa, Fla] : University of South Florida, 2008. http://purl.fcla.edu/usf/dc/et/SFE0002429.
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Slama, Nader. "Inclusion of dissipative effects in quantum time-dependent mean-field theories." Thesis, Toulouse 3, 2015. http://www.theses.fr/2015TOU30063.
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Les théories de champ moyen quantique représentent une base robuste pour la description de la dynamique de nombreux systèmes physiques, des noyaux aux systèmes moléculaires et aux agrégats. Cependant, le traitement incomplet des corrélations électroniques au niveau du champ moyen empêche de donner une description propre de la dynamique, en particulier la dynamique dans les régimes dissipatifs. La dissipation est intrinsèquement liée à la thermalisation qui représente le phénomène cible à d'écrire dans ce travail. Nous avons exploré un schéma purement quantique en terme des matrices densités et qui consiste en l'inclusion des corrélations de type collisions, responsables de la thermalisation dans les systèmes quantiques finis. Ceci est fait en traitant les corrélations entre deux particules avec la théorie des perturbations dépendantes du temps tout au long d'un intervalle de temps. Ceci permet de créer un ensemble d'états de type champ moyen pur pour les différentes configurations. Ces états sont traités stochastiquement dans la dynamique et fournissent en moyenne un état corrélé. Nous proposons dans ce travail une reformulation de cette théorie en terme des fonctions d'ondes où les corrélations sont traitées comme des transitions multiples de type particule-trou, limitées aux transitions deux-particules-deux-trous dans notre cas. On applique le schéma obtenu à un modèle unidimensionnel simulant de petites molécules. La capacité de cette théorie à introduire les effets dissipatifs dans le cadre du champ moyen est illustrée à travers plusieurs observables tels que les matrices à un et deux corps, les nombres d'occupation et l'entropie à un corps<br>Quantum mean field theories represent a robust basis for the description of many dynamical situations from nuclei to molecular systems and clusters. However, the missing of electronic correlations on top of mean field prevents them to give a proper description of the dynamics, in particular dissipative dynamics. Dissipation is intrinsically linked to thermalization which represents the target phenomenon to be described in this thesis. We thus explore a fully quantum mechanical strategy proposed in terms of density matrices in the case of nuclear collisions and which consists in the inclusion of collisional correlations responsible of thermalization in quantum finite systems. This is done by treating two body correlations in time dependent perturbation theory along a certain time span that allows to create an ensemble of pure mean field states for different configurations. These states are used into the dynamics, stochastically, providing in the average one correlated state. We propose in this work a reformulation of this theory in term of wave functions where correlations are translated into multiple particle-hole transitions, restricted to two-particles-two-holes transitions in our case. We apply the obtained scheme to a one dimensional model simulating small molecules. The ability of this theory to include dissipative effects on top of mean field is illustrated through several observables such as the one and two body density matrices, the occupation numbers and the one body entropy
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Rappl, Florian [Verfasser], and T. [Akademischer Betreuer] Wettig. "Feynman Diagram Sampling for Quantum Field Theories on the QPACE 2 Supercomputer / Florian Rappl. Betreuer: T. Wettig." Regensburg : Universitätsbibliothek Regensburg, 2016. http://d-nb.info/1100276653/34.
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Toranzos, Soria Gary Antonio. "Development of a method for the concentration of rotaviruses from water and its application to field sampling." Diss., The University of Arizona, 1985. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_1985_349_sip1_w.pdf&type=application/pdf.
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Lewis, Richard Henry. "The reproducibility of field measurements and the effect of wind speed on the sampling of airborne dust." Thesis, University of Salford, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335409.
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Willett, Evan James. "PREFERENTIAL PATHWAYS FOR VAPOR INTRUSION: SITE SCREENING AND FIELD SAMPLING OF SEWERS TO ASSESS INHALATION EXPOSURE RISKS." UKnowledge, 2018. https://uknowledge.uky.edu/ce_etds/64.
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Hazardous waste sites and aging wastewater infrastructure are common in the United States. There are hundreds of thousands of contaminated sites and more than a million miles of sewer pipes. Populations living close to hazardous waste sites often suffer from increased risk of adverse health effects due to exposure to contaminated environmental media. Vapor intrusion is one process by which nearby populations can be exposed to volatile organic compounds (VOCs). Aging wastewater infrastructure is important for vapor intrusion site assessments because sewer pipes can serve as preferential vapor transport pathways. Near contaminated sites, pipe deterioration allows migration of contaminants into sewers and potential accumulation of chemical vapors in sewer gas and nearby buildings. The objectives of this study are to develop a screening-level method to identify contaminated sites where additional evaluation of vapor intrusion is necessary, and then conduct field sampling at these sites to investigate sewers as potential vapor intrusion pathways. Sampling was conducted at four study sites, which consist of former and current dry cleaning facilities located in Lexington, Kentucky. The results of this study demonstrate that preferential vapor intrusion pathways such as sewers can facilitate the spread of vapor intrusion exposure risks beyond source areas of contamination.
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Seyyedhasani, Hasan. "INTELLIGENT UAV SCOUTING FOR FIELD CONDITION MONITORING." UKnowledge, 2018. https://uknowledge.uky.edu/ece_etds/113.
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Precision agriculture requires detailed and timely information about field condition. In less than the short flight time a UAV (Unmanned Aerial Vehicle) can provide, an entire field can be scanned at the highest allowed altitude. The resulting NDVI (Normalized Difference Vegetation Index) imagery can then be used to classify each point in the field using a FIS (Fuzzy Inference System). This identifies areas that are expected to be similar, but only closer inspection can quantify and diagnose crop properties. In the remaining flight time, the goal is to scout a set of representative points maximizing the quality of actionable information about the field condition. This quality is defined by two new metrics: the average sampling probability (ASP) and the total scouting luminance (TSL). In simulations, the scouting flight plan created using a GA (Genetic Algorithm) significantly outperformed plans created by grid sampling or human experts, obtaining over 99% ASP while improving TSL by an average of 285%.
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Boswell, Ammon K. "Rangeland Monitoring Using Remote Sensing: An Assessment of Vegetation Cover Comparing Field-Based Sampling and Image Analysis Techniques." BYU ScholarsArchive, 2015. https://scholarsarchive.byu.edu/etd/4418.
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Rangeland monitoring is used by land managers for assessing multiple-use management practices on western rangelands. Managers benefit from improved monitoring methods that provide rapid, accurate, cost-effective, and robust measures of rangeland health and ecological trend. In this study, we used a supervised classification image analysis approach to estimate plant cover and bare ground by functional group that can be used to monitor and assess rangeland structure. High-resolution color infrared imagery taken of 40 research plots was acquired with a UltraCam X (UCX) digital camera during summer 2011. Ground estimates of cover were simultaneously collected by the Utah Division of Wildlife Resources' Range Trend Project field crew within these same areas. Image analysis was conducted using supervised classification to determine percent cover from Red, Green, Blue and infrared images. Classification accuracy and mean difference between cover estimates from remote sensed imagery and those obtained from the ground were compared using an accuracy assessment with Kappa statistic and a t-test analysis, respectively. Percent cover estimates from remote sensing ranged from underestimating the surface class (rock, pavement, and bare ground) by 27% to overestimating shrubs by less than 1% when compared to field-based measurements. Overall accuracy of the supervised classification was 91% with a kappa statistic of 0.88. The highest accuracy was observed when classifying surface values (bare ground, rock) which had a user's and producer's accuracy of 92% and 93%, respectively. Although surface cover varied significantly from field-based estimates, plant cover varied only slightly, giving managers an option to assess plant cover effectively and efficiently on greater temporal and spatial extents.
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Liang, Dong. "Issues in Bayesian Gaussian Markov random field models with application to intersensor calibration." Diss., University of Iowa, 2009. https://ir.uiowa.edu/etd/400.
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A long term record of the earth's vegetation is important in studies of global climate change. Over the last three decades, multiple data sets on vegetation have been collected using different satellite-based sensors. There is a need for methods that combine these data into a long term earth system data record.
The Advanced Very High Resolution Radiometer (AVHRR) has provided reflectance measures of the entire earth since 1978. Physical and statistical models have been used to improve the consistency and reliability of this record. The Moderated Resolution Imaging Spectroradiometer (MODIS) has provided measurements with superior radiometric properties and geolocation accuracy. However, this record is available only since 2000. In this thesis, we perform statistical calibration of AVHRR to MODIS. We aim to: (1) fill in gaps in the ongoing MODIS record; (2) extend MODIS values back to 1982.
We propose Bayesian mixed models to predict MODIS values using snow cover and AVHRR values as covariates. Random effects are used to account for spatiotemporal correlation in the data. We estimate the parameters based on the data after 2000, using Markov chain Monte Carlo methods. We then back-predict MODIS data between 1978 and 1999, using the posterior samples of the parameter estimates. We develop new Conditional Autoregressive (CAR) models for seasonal data. We also develop new sampling methods for CAR models.
Our approach enables filling in gaps in the MODIS record and back-predicting these values to construct a consistent historical record. The Bayesian framework incorporates multiple sources of variation in estimating the accuracy of the obtained data. The approach is illustrated using vegetation data over a region in Minnesota.
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Chen, Jing. "Development of methodology to correct sampling error associated with FRM PM10 samplers." [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-1424.
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Qureshi, Muhammad Ayyaz [Verfasser], Thomas [Akademischer Betreuer] Eibert, and Hendrik [Akademischer Betreuer] Rogier. "Near-Field Error Analysis and Efficient Sampling Techniques for the Fast Irregular Antenna Field Transformation Algorithm / Muhammad Ayyaz Qureshi. Gutachter: Thomas Eibert ; Hendrik Rogier. Betreuer: Thomas Eibert." München : Universitätsbibliothek der TU München, 2013. http://d-nb.info/1045345717/34.
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Zoino, Jayson Jon. "Field Methods, Sampling Strategies, Historical Documents, and Data Redundancy| A Study of Historic Tenant Farmsteads in Leflore County, Mississippi." Thesis, Mississippi State University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10640045.
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<p> Historic tenant farmsteads are often thought to be redundant archaeological resources because of their limited temporal range and function which acts to limit the diversity of their archaeological assemblages. However, work has not been done that confirms this equivalence, and archaeologists often write off tenant farmsteads as being too modern or too disturbed to warrant investigation. This is a problematic approach as tenant farmsteads are quickly eroding from the American landscape and a representative sample of sites need to be investigated and preserved before they’re gone. This thesis tests different sampling strategies and field methods that may allow for the efficient investigation of tenant farmsteads without jeopardizing historical knowledge. The results show that the sites studied in this thesis are in fact redundant and a number of different methods can be used to investigate them in a much more efficient manner.</p><p>
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Lindemuth, Robert M. "A Field Trial Comparison of Sampling Methods for Estimating Basal Area and Volume in Partially Harvested Stands in Maine." Fogler Library, University of Maine, 2007. http://www.library.umaine.edu/theses/pdf/LindemuthRM2007.pdf.
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Thomason, Jamie Cindi. "AN ASSESSMENT OF SUSPENDED SEDIMENT IN WEEKS BAY RESERVE, BALDWIN COUNTY, ALABAMA, USING GEOSPATIAL MODELING AND FIELD SAMPLING METHODS." MSSTATE, 2008. http://sun.library.msstate.edu/ETD-db/theses/available/etd-05222008-170935/.
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This study compares suspended sediment and land use/land cover in the watershed of Weeks Bay, Alabama. Using Landsat thematic mapper imagery, potential high and low erosion sites were determined based on the increase in urban development form 2002 to 2005. In situ sediment sampling was used to test the hypothesis that the high erosion potential sites have larger amounts of suspended sediments. Additionally, sampling was performed along the Fish and Magnolia rivers to establish a background total suspended sediment level. The background study established an average total suspended sediment concentration of 18.71 mg/L for the Fish River and 17.47 mg/L for the Magnolia River, which are higher than previous studies. The results of the comparison between suspended sediments and land use/land cover proved to be more complex than expected due to variation in precipitation, to the 30 m satellite resolution, and to the criteria for classifying urban land use.
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Liang, Dong Cowles Mary Kathryn. "Issues in Bayesian Gaussian Markov random field models with application to intersensor calibration." Iowa City : University of Iowa, 2009. http://ir.uiowa.edu/etd/400.
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LaJeunesse, Katherine J. "Covariation in plant abundance and diversity estimators in an old field herbaceous plant community." Miami University Honors Theses / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=muhonors1177560873.
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Silvadasan, Xavier. "Environmental performance of steel grit and specialty sand as abrasives." ScholarWorks@UNO, 2004. http://louisdl.louislibraries.org/u?/NOD,175.
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Thesis (M.S.)--University of New Orleans, 2004.<br>Title from electronic submission form. "A thesis ... in partial fulfillment of the requirements for the degree of Master of Science in the Department of Civil and Environmental Engineering."--Thesis t.p. Vita. Includes bibliographical references.
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Gillefalk, Mikael, and Felix Lindberg. "Sediment State and Flow – An Investigation of Sediment Pollution and Transport in the Bîc River, Republic of Moldova. : A Minor Field Study." Thesis, KTH, Mark- och vattenteknik (flyttat 20130630), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-171825.
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The Bîc River in the Republic of Moldova is a heavily polluted water body. Along the river stretch, from a small creek in Sipoteni close to the river mouth at Gura Bîcului, sediment samples were taken using a very cost-effective method and analyzed for a number of pollutants. The results showed very high levels of petroleum products in and downstream of the city of Chişinău, situated in the middle of the river basin, ex-ceeding even the guideline value for cleanup of industrial land. Concentrations of heavy metals were detected at all sample points, exceeding the Lowest Effect Level (LEL) in 37 out of 48 samples and the Probable Effect Level (PEL) in four of them. High concentrations of nutrients (N and P) were detected, especially outside of the city, where concentrations exceeded even the Severe Effect Level (SEL) for both N and P at one site. DDT concentrations were highest at the beginning of the river, the concentrations becoming lower and lower when getting closer to the river mouth. At three of the six sampling sites, DDT concentrations exceeded the LEL. PCB levels were lower than the LEL. This was attributed to unsuitable handling of the samples before analysis and therefore the PCB concentration levels requires further investiga-tion. The continued monitoring of the sediments is of great need, therefore a proposal for a monitoring program was written. It was estimated that Bîc contributes 118000 tons of suspended particles to Dniester each year, almost 60 % more per km2 than Dniester contributes to the Black Sea.
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Iran, Pour Siavash [Verfasser], and Nico [Akademischer Betreuer] Sneeuw. "Sampling the earth's time-variable gravity field from satellite orbit : design of future gravity satellite missions / Siavash Iran Pour. Betreuer: Nico Sneeuw." Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2013. http://d-nb.info/104368879X/34.
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Arora, Akash. "Multi-Modal Active Perception for Robotic Information Gathering in Science Missions." Thesis, The University of Sydney, 2018. http://hdl.handle.net/2123/18415.
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Information gathering using mobile robots in dangerous and remote environments such as deep sea, underground, and outer space has significantly improved humanity's ability to understand the world. Typically in such science missions, a robot's role is limited to that of a sensing platform which passively gathers data along prescribed waypoints. Higher level decision making such as planning where to go in the context of mission objectives, making inferences from observations, and deciding which sensing modalities to deploy, is largely handled by a supervisory science team working remotely. However, communication constraints can hinder these processes and hence the rate of scientific progress. This thesis presents a novel active perception approach to science missions that aims to reduce robots' reliance on human supervision and improve science productivity by encoding an approximation of scientists' domain knowledge, inference, and decision making processes on-board the robot. Science missions can involve two complexities that are not addressed by existing approaches to robotic information gathering. Firstly, the variables of scientific interest may not be directly observable from on-board sensors, and instead require combining multi-modal proxy measurements with non-trivial amounts of scientific domain knowledge to infer. Secondly, robots may be equipped with multiple sensing modalities which measure different environmental variables and have some sensing cost associated with their usage. The first contribution of the thesis is the formulation of these requirements into a new information gain maximization sensor planning problem called scientific information gathering. An initial solution is presented which addresses scientific information gathering as two separate subproblems- estimating the variables of interest from sensor data by encoding an approximation of scientific domain knowledge, and planning paths and sensing actions that maximize the information gained on the variable of interest. Efficient solutions to these subproblems form the next two contributions. To tackle the first subproblem, a Bayesian network (BN) architecture that creates a probabilistic mapping between observations and the variables of scientific interest is proposed. The BN intuitively and jointly models critical aspects of scientific knowledge, as well as other prior knowledge such as sensor and classifier models, while the proposed network structure allows the robot to robustly handle noisy observations, has fast inference times, allows recursive estimation of key variables, and can utilize online parameter tuning to overcome initial modeling uncertainties. To address the second subproblem, a sampling-based forward simulation approach based on Monte Carlo tree search (MCTS) is proposed, which exploits the domain knowledge encoded in the BN and efficiently plans informative sensing actions with multiple sensing modalities in partially observable environments. The computational complexity of the BN-MCTS active perception framework does not grow with the number of observations taken, and allows long horizon planning in an anytime manner, making it highly applicable to field robots operating in large scale environments. The final contribution of the thesis is the application and evaluation of the proposed approach to three instances of scientific information gathering with unique mission constraints. The first is a Mars exploration mission where the robot is required to infer the geological type of locations in the environment by autonomously planning informative paths and observing geological features. The second scenario is modelled on the NASA Mojave Volatiles Prospector (MVP) project, where the robot attempts to autonomously refine errors in prior scientific knowledge during the mission. The final scenario explores how the active perception approach can be applied to next generation autonomous entry descent and landing (EDL) missions, which requires reasoning about temporal constraints. Extensive simulation results with synthetic and real data show that the proposed active perception approach significantly outperforms both myopic and passive approaches. Algorithms were also implemented on a prototype planetary rover along with supporting subsystems such as image processing modules, localization, and control. Autonomous end to end planning and execution of a science mission is demonstrated on an analog Mars environment, and key practical challenges in deploying the approach on real systems are discussed.
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Cardamone, Salvatore. "An interacting quantum atoms approach to constructing a conformationally dependent biomolecular force field by Gaussian process regression : potential energy surface sampling and validation." Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/an-interacting-quantum-atoms-approach-to-constructing-a-conformationally-dependent-biomolecular-force-field-by-gaussian-process-regression-potential-energy-surface-sampling-and-validation(508ed450-9033-4bc9-8522-690d5a7909eb).html.
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The energetics of chemical systems are quantum mechanical in origin and dependent upon the internal molecular conformational degrees of freedom. "Classical force field" strategies are inadequate approximations to these energetics owing to a plethora of simplifications- both conceptual and mathematical. These simplifications have been employed to make the in silico modelling of molecular systems computationally tractable, but are also subject to both qualitative and quantitative errors. In spite of these shortcomings, classical force fields have become entrenched as a cornerstone of computational chemistry. The Quantum Chemical Topological Force Field (QCTFF) has been a central re search theme within our group for a number of years, and has been designed to ameliorate the shortcomings of classical force fields. Within its framework, one can undertake a full spatial decomposition of a chemical system into a set of finite atoms. Atomic properties are subsequently obtained by a rigorous quantum mechanical treatment of the resultant atomic domains through the theory of Interacting Quantum Atoms (IQA). Conformational dependence is accounted for in theQCTFF by use of Gaussian Process Regression, a machine learning technique. In so doing, one constructs an analytical function to provide a mapping from a molecular conformation to a set of atomic energetic quantities. One can subsequently conduct dynamics with these energetic quantities. The notion of "conformational sampling" is shown to be of key importance to the proper construction of the QCTFF. Conformational sampling is a key theme in this work, and a subject that we will expatiate. We suggest a novel conformational sampling scheme, and attempt a number of conformer subset selection strategies to construct optimal machine learning models. The QCTFF is then applied to carbohydrates for the first time, and shown to produce results well within the commonly invoked threshold of "chemical accuracy"- O(β^{-1}), where β is the thermodynamic beta. Finally, we present a number of methodological developments to aid in both the accuracy and tractability of predicting ab initio vibrational spectroscopies.
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Winter, Jan-Christoph [Verfasser], Stephan [Akademischer Betreuer] Völker, Steve [Akademischer Betreuer] Fotios, Stephan [Gutachter] Völker, Steve [Gutachter] Fotios, and Christoph [Gutachter] Schierz. "Spatial sampling of a driver’s visual field: characterising peripheral adaptation / Jan-Christoph Winter ; Gutachter: Stephan Völker, Steve Fotios, Christoph Schierz ; Stephan Völker, Steve Fotios." Berlin : Technische Universität Berlin, 2018. http://d-nb.info/1165650363/34.
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Chen, Yong. "New Calibration Approaches in Solid Phase Microextraction for On-Site Analysis." Thesis, University of Waterloo, 2004. http://hdl.handle.net/10012/1285.
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Calibration methods for quantitative on-site sampling using solid phase microextraction (SPME) were developed based on diffusion mass transfer theory. This was investigated using adsorptive polydimethylsiloxane/divinylbenzene (PDMS/DVB) and Carboxen/polydimethylsiloxane (CAR/PDMS) SPME fiber coatings with volatile aromatic hydrocarbons (BTEX: benzene, toluene, ethylbenzene, and o-xylene) as test analytes. Parameters that affected the extraction process (sampling time, analyte concentration, water velocity, and temperature) were investigated. Very short sampling times (10-300 s) and sorbents with a strong affinity and large capacity were used to ensure a 'zero sink' effect calibrate process. It was found that mass uptake of analyte changed linearly with concentration. Increase of water velocity increased mass uptake, though the increase is not linear. Temperature did not affect mass uptake significantly under typical field sampling conditions. To further describe rapid SPME analysis of aqueous samples, a new model translated from heat transfer to a circular cylinder in cross flow was used. An empirical correlation to this model was used to predict the mass transfer coefficient. Findings indicated that the predicted mass uptake compared well with experimental mass uptake. The new model also predicted rapid air sampling accurately. To further integrate the sampling and analysis processes, especially for on-site or <i>in-vivo</i> investigations where the composition of the sample matrix is very complicated and/or agitation of the sample matrix is variable or unknown, a new approach for calibration was developed. This involved the loading internal standards onto the extraction fiber prior to the extraction step. During sampling, the standard partially desorbs into the sample matrix and the rate at which this process occurs, was for calibration. The kinetics of the absorption/desorption was investigated, and the isotropy of the two processes was demonstrated, thus validating this approach for calibration. A modified SPME device was used as a passive sampler to determine the time-weighted average (TWA) concentration of volatile organic compounds (VOCs) in air. The sampler collects the VOCs by the mechanism of molecular diffusion and sorption on to a coated fiber as collection medium. This process was shown to be described by Fick's first law of diffusion, whereby the amount of analyte accumulated over time enable measurement of the TWA concentration to which the sampler was exposed. TWA passive sampling with a SPME device was shown to be almost independent of face velocity, and to be more tolerant of high and low analyte concentrations and long and short sampling times, because of the ease with which the diffusional path length could be changed. Environmental conditions (temperature, pressure, relative humidity, and ozone) had little or no effect on sampling rate. When the SPME device was tested in the field and the results compared with those from National Institute of Occupational Health and Safety (NIOSH) method 1501 good agreement was obtained. To facilitate the use of SPME for field sampling, a new field sampler was designed and tested. The sampler was versatile and user-friendly. The SPME fiber can be positioned precisely inside the needle for TWA sampling, or exposed completely outside the needle for rapid sampling. The needle is protected within a shield at all times hereby eliminating the risk of operator injury and fiber damage. A replaceable Teflon cap is used to seal the needle to preserve sample integrity. Factors that affect the preservation of sample integrity (sorbent efficiency, temperature, and sealing materials) were studied. The use of a highly efficient sorbent is recommended as the first choice for the preservation of sample integrity. Teflon was a good material for sealing the fiber needle, had little memory effect, and could be used repeatedly. To address adsorption of high boiling point compounds on fiber needles, several kinds of deactivated needles were evaluated. RSC-2 blue fiber needles were the more effective. A preliminary field sampling investigation demonstrated the validity of the new SPME device for field applications.
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Midgarden, David Gunder. "Spatial distribution of western corn rootworm (Diabrotica virgifera virgifera Leconte) trap counts and evaluation of a novel method for sampling soil pests of field corn." Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-06302009-040212/.
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Mausel, Dave L. "Release and monitoring of Laricobius nigrinus (Coleoptera: Derodontidae) for biological control of the hemlock woolly adelgid in the eastern US." Diss., Virginia Tech, 2007. http://hdl.handle.net/10919/29785.
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Different Laricobius nigrinus Fender release locations, numbers of predators, and timing of release were evaluated for biological control of the hemlock woolly adelgid (HWA), Adelges tsugae Annand (Hemiptera: Adelgidae). It established at 59% of the sites and location was the most important factor related with establishment and abundance, HWA density, and hemlock vigor index. Cold locations had poor establishment or low abundance, declines in HWA density, and increases in hemlock vigor over time. Paired release and control sites detected a predator impact on HWA density, but densities remained high and tree vigor declined. The phenology of L. nigrinus, L. rubidus LeConte, and HWA were studied at a field insectary and the species were highly synchronized. A cage exclusion study showed that HWA survival and density were lower and ovisac disturbance was higher when exposed to predation. To improve L. nigrinus monitoring, we compared beat sheets for adults or branch clipping for immatures, and the host searching behavior of L. nigrinus was studied to understand how it locates a tree and HWA. In the Appalachians, beat sheet sampling resulted in false negatives as larvae were collected by branch clipping. Adults orientated to a tree visually, fed when prey were present and flew when absent, and showed different search patterns on infested versus uninfested trees. In Seattle, both sampling methods detected L. nigrinus because the predator was common. Predator : prey ratios were high at heavily infested sites in Seattle and low in the eastern US, where is has been released recently. Partial life tables were constructed for HWA sistentes at four sites for 2 yr in Seattle. Unspecified causes of nymph and adult mortality were high and L. nigrinus was the dominant predator of ovisacs. Adult L. nigrinus abundance was positively related to HWA density and immature abundance was related to ovisac density, indicating an aggregation and numerical response to its prey. Laricobius nigrinus has not demonstrated complete biological control of HWA to date, but it may do so in the future and continued release is justified.<br>Ph. D.
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Meňhart, Pavel. "Odstranění prokladu v nekomprimovaných digitálních videosekvencích." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-217795.
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Interlacing is the process of frame scanning and frame displaying being based on the even and uneven lines‘ interchanging. This framework originated along with the PAL and NTSC television standards‘ formation in the course of 1930s. The process mentioned above stopped frames displayed on older TV sets from flashing. Nevertheless, there is a disadvantage of the frame processed after this manner, consisting in its attribute to be displayed in a clean-cut way just on classical TV sets. However, plasma and LCD television appliances, projectors and computer monitors always display the entire frame all at once, therefore composing it of the both fields, yet not being acquired concurrently, differing in moving objects‘ positions, moreover their contours are doubled, frayed and unfocussed. This master´s thesis deals with fundamentals of the interlaced video signal‘s formation, problems coming about at featuring the interlaced video like this, followed by operating methods of deinterlacing itself. In conclusion, there are my own softwares presented, having been developed in MATLAB computer environment and software command language C, and implementing some of the operating methods designed for deinterlacing in uncompressed digital video sequences.
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Parrish, Douglas K. "Application of solid phase microextraction with gas chromatography-mass spectrometry as a rapid, reliable, and safe method for field sampling and analysis of chemical warfare agent precursors /." Download the dissertation in PDF, 2005. http://www.lrc.usuhs.mil/dissertations/pdf/Parrish2005.pdf.
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Trask, Catherine Mary. "Balancing efficiencies and tradeoffs in epidemiological field studies : evaluating EMG exposure assessment for low back injury risk factors in heavy industry." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/1539.
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In order to investigate the etiology of and evaluate interventions for work-related back injuries, researchers need efficient, accurate occupational exposure assessment methods suitable for large samples. The chapters in this thesis examine critical decisions using electromyography (EMG): How should exposure be measured? For what duration? Who should be measured, and how many times?
Low-back EMG, or muscle activity data, was collected during 138 full-shift field measurements over 30 different job titles at 50 different worksites in 5 heavy industries: forestry, transportation, wood products, construction, and warehousing. Observations and self-reports of posture, manual materials handling (MMH), and driving exposures were collected concurrently.
1) Variability of EMG calibration measurements was investigated on right/left sides, multiple trials, 4 positions, and pre/post-shift. Position accounts for the majority of explained variability; there is little to gain by measuring multiple trials or pre- and post-shift, but measuring both sides and multiple positions is worthwhile.
2) Observation and self-report data were easier to collect and cheaper than the EMG direct measure. Costs and successful field performance need to be weighed against the added data detail when making choices about exposure assessment techniques for epidemiological studies.
3) Observed and self-reported exposures were used to predict EMG exposure metrics using mixed multiple linear regression models. Regression models using observed variables predicted 43-50% of the variability in the EMG metrics, while self-reported variables predicted 21%-36%. The observation exposure model provides a low-cost alternative to direct measurement. The self-reported exposure model should be considered with more caution.
4) Full-shift EMG data was resampled for 4, 2, and 1 hour, and for 10 and 2 minute durations to determine the optimal sampling duration. Bias was consistently low, but shorter durations had higher absolute error, percentage error, and limits of agreement. Durations of 4 and 2 hours may be acceptable but those less than 1 hour had large errors.
5) Components of EMG variance were calculated between- and within-subject, and between- industry, company, job, and post hoc grouping. Resolution, contrast, and exposure-response relationship attenuation were calculated for each grouping scheme. The post hoc scheme had the highest contrast and lowest resolution.
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Benamara, Tariq. "Full-field multi-fidelity surrogate models for optimal design of turbomachines." Thesis, Compiègne, 2017. http://www.theses.fr/2017COMP2368.
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L’optimisation des différents composants d’une turbomachine reste encore un sujet épineux, malgré les récentes avancées théoriques, expérimentales ou informatiques. Cette thèse propose et investigue des techniques d’optimisation assistées par méta-modèles vectoriels multi-fidélité basés sur la Décomposition aux Valeurs Propres (POD). Le couplage de la POD à des techniques de modélisation multifidélité permet de suivre l’évolution des structures dominantes de l’écoulement en réponse à des déformations géométriques. Deux méthodes d’optimisation multi-fidélité basées sur la POD sont ici proposées. La première consiste en une stratégie d’enrichissement adaptée aux modèles multi-fidelité par Gappy-POD (GPOD). Celle-ci vise surtout des problèmes associés à des simulations basse-fidélité à coût de restitution négligeable, ce qui la rend difficilement utilisable pour la conception aérodynamique de turbomachines. Elle est néanmoins validée sur une étude du domaine de vol d’une aile 2D issue de la littérature. La seconde méthodologie est basée sur une extension multi-fidèle des modèles par POD Non-Intrusive (NIPOD). Cette extension naît de la ré-interprétation du concept de POD Contrainte (CPOD) et permet l’enrichissement de l’espace réduit par ajout important d’information basse-fidélité approximative. En seconde partie de cette thèse, un cas de validation est introduit pour valider les méthodologies d’optimisation vectorielle multi-fidélité. Cet exemple présente des caractéristiques représentatives des problèmes d’optimisation de turbomachines. La capacité de généralisation des méta-modèles par NIPOD multifidélité proposés est comparée, aussi bien sur cas analytique qu’industriel, à des techniques de méta-modélisation issues de la littérature. Enfin, nous utilisons la méthode développée au cours de cette thèse pour l’optimisation d’un étage et demi d’un compresseur basse-pression et comparons les résultats obtenus à des approches à l’état de l’art<br>Optimizing turbomachinery components stands as a real challenge despite recent advances in theoretical, experimental and High-Performance Computing (HPC) domains. This thesis introduces and validates optimization techniques assisted by full-field Multi-Fidelity Surrogate Models (MFSMs) based on Proper Orthogonal Decomposition (POD). The combination of POD and Multi-Fidelity Modeling (MFM) techniques allows to capture the evolution of dominant flow features with geometry modifications. Two POD based multi-fidelity optimization methods are proposed. Thefirst one consists in an enrichment strategy dedicated to Gappy-POD (GPOD)models. It is more suitable for instantaneous low-fidelity computations whichmakes it hardly tractable for aerodynamic design of turbomachines. This methodis demonstrated on the flight domain study of a 2D airfoil from the literature. The second methodology is based on a multi-fidelity extension to Non-IntrusivePOD (NIPOD) models. This extension starts with a re-interpretation of theConstrained POD (CPOD) concept and allows to enrich the reduced spacedefinition with abondant, albeit inaccurate, low-fidelity information. In the second part of the thesis, a benchmark test case is introduced to test fullfield multi-fidelity optimization methodologies on an example presenting featuresrepresentative of turbomachinery problems. The predictability of the proposedMulti-Fidelity NIPOD (MFNIPOD) surrogate models is compared to classical surrogates from the literature on both analytical and industrial-scale applications. Finally, we employ the proposed tool to the shape optimization of a 1.5-stage boosterand we compare the obtained results with standard state of the art approaches