Dissertations / Theses on the topic 'Mixing States'
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Hazelton, William Donald. "Configuration mixing of quark states in nucleons and other baryons in the MIT bag model /." Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/9770.
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Shepard, Katherine Elizabeth. "King mackerel population dynamics and stock mixing in the United States Atlantic Ocean and Gulf of Mexico." [Pensacola, Fla.] : University of West Florida, 2008. http://purl.fcla.edu/fcla/etd/WFE0000143.
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Cubides, Victor Andres Vargas. "Sobre existência de estados de equilíbrio e limite em temperatura zero para shifts de Markov topologicamente mixing." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/45/45131/tde-25112016-214355/.
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O objetivo desta tese é demonstrar que para um subshift de Markov topologicamente transitivo com alfabeto enumerável e um potencial ƒ com pressão de Gurevic finita e variação limitada (ƒ) < ∞, existe um único estado de equilíbrio µtƒ para cada t > 1, e a família (µtƒ)t>1 tem um ponto de acumulação quando t > ∞. Além disso se também supomos que o ƒ é um potencial de Markov, demonstramos que a família de estados de equilíbrio (µtƒ)t>1 converge quando t > ∞. Finalmente demonstramos a continuidade em ∞ da entropia com respeito ao parâmetro t. Estes resultados não dependem da hipótese de existência de medidas de Gibbs.The aim of this thesis is to prove that for a topologically transitive Markov subshift with countable alphabet and a summable potential ƒ with finite topological pressure Gurevic and bounded variation (ƒ) < ∞, there exists an equilibrium state µtƒ tf for each t > 1 and the family of equilibrium states (µtƒ)t>1 associated to each potential tf has an accumulation point at t > ∞. Moreover if we also assume that ƒ is a Markov potential we prove that the equilibrium states family (µtƒ)t>1 converges when t > ∞. Finally we prove the continuity at ∞ of the entropy with respect to the parameter t. These results do not depend on assuming the existence of Gibbs measures.
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Kawaguchi, Genta. "Systematic Control of the Electronic States in Halogen-Bonded π-d Hybrid Molecular Conductors with Employing Anion Mixing, High Pressure, and Strong Magnetic Field." 京都大学 (Kyoto University), 2016. http://hdl.handle.net/2433/216168.
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Elston, Susan Anne. "Secondary Circulation in a Sinuous Coastal Plain Estuary." Diss., Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-05042005-143327/.
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Thesis (Ph. D.)--Earth and Atmospheric Sciences, Georgia Institute of Technology, 2005.Dr. Curry, Judith, Committee Co-Chair ; Dr. Blanton, Jackson - Committee Chair, Committee Chair ; Dr. Cunnold, Derek, Committee Member ; Dr. Seim, Harvey, Committee Member ; Dr. Webster, Donald, Committee Member ; Dr. Webster, Peter, Committee Member ; Dr. Wong, Kuo, Committee Member.
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Peacock, A. T. "Ion beam mixing of thin films on aluminium." Thesis, Lancaster University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372540.
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Barrett, Graham Robert. "Temporal solutions of the four wave mixing interaction in photorefractives." Thesis, King's College London (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244196.
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Harack, Benjamin. "Energy level mixing and hyperfine effects in double vertical quantum dots." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=114576.
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Building upon transport measurements conducted on two vertical double quantum dot devices, we model and analyze data to investigate intra-dot energy level mixing and long-period oscillations of current. While experimental single-particle spectra are well-described overall by the spectra of elliptical harmonic confinement potentials, the observation of level anticrossings in the single-particle spectra indicates that the real dot potentials are not perfectly elliptical harmonic. We successfully model the level crossing phenomenon, and the spectrum as a whole, by adding small defects to the ideal elliptical harmonic confinement potential. By checking the resulting spectra against the experimental data and only keeping the defects which improve the match, we iteratively develop a potential that gives rise to a spectrum that agrees very well with experiment.We investigate a tunneling current feature that is hysteretic under B-field sweeps and exhibits long-lived quasi-periodic temporal oscillations of current. Previous observations of similar current oscillations have been limited to the low-bias spin blockade regime, while these are observed at high bias (-12 mV) and high magnetic field (~4 T). We apply signal processing techniques such as autocorrelation and power spectrum analysis to quantify the oscillatory behaviour of the current measurements, revealing a strong central periodicity of ~100-150 s for the oscillations and a peak in power spectral density that is almost four orders of magnitude higher than background noise. In addition, we quantify a number of other aspects of this oscillating feature, including the transition of current observations from the `high' state to the `low' state as magnetic field is swept through the feature. Though a model explaining the origin of these phenomena is still lacking, they are postulated to be the result of hyperfine interactions.En s'appuyant sur des mesures de transport effectuées sur deux dispositifs qui incluent des boîtes quantiques doubles verticales, nous modélisons et analysons les données pour étudier le mélange des niveaux d'énergie intra-boîte et les oscillations du courant de longue période. Bien que les spectres expérimentaux à une particule soient en général bien décrits par les spectres des potentiels de confinement harmoniques elliptiques, l'observation d'anticroisements des niveaux dans les spectres à une particule indique que les potentiels réels des boîtes ne sont pas parfaitement harmoniques elliptiques. Nous avons réussi à modéliser avec succès le phénomène de croisement des niveaux, ainsi que le spectre dans son ensemble, en ajoutant de petits défauts au potentiel de confinement harmonique elliptique idéal. En comparant les spectres résultant aux données expérimentales et en ne retenant que les défauts qui améliorent la concordance avec ces données, nous avons developpé itérativement un potentiel qui donne lieu à un spectre s'accordant très bien avec l'expérience. Nous étudions une caractéristique du courant tunnel qui est hystérétique lors d'un balayage du champ magnétique et qui montre des oscillations temporelles du courant quasi-périodiques et de longue durée de vie. Les précédentes observations de semblables oscillations du courant ont été limitées au régime de blocage de spin à basse tension, tandis que celles-ci sont observées à tension élevée (-12 mV) et à large champ magnétique (~ 4 T). Nous appliquons des techniques de traitement de signal telles que l'autocorrélation et l'analyse du spectre de puissance pour quantifier le comportement oscillatoire des mesures de courant, révélant une forte périodicité centrale de ~ 100-150 s des oscillations et un maximum de la densité spectrale de puissance qui est près de quatre ordres de grandeur supérieur au bruit de fond intrinsèque. En outre, nous quantifions un certain nombre d'autres aspects de cette fonction oscillante, y compris la transition des observations du courant de l'etat `haut' vers l'état `bas' lorsqu'un champ magnétique est balayé à travers la caractéristique. Bien qu'un modèle expliquant l'origine de ces phénomènes ne soit pas encore disponible, ils sont postulés être le résultat d'interactions hyperfine.
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Bergman, Niclas. "Aspects of probabalistic serviceability limit state design of dry deep mixing." Doctoral thesis, KTH, Jord- och bergmekanik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-168596.
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An expanding population and increased need for infrastructure increasingly necessitate construction on surfaces with poor soil conditions. To facilitate the construction of buildings, roads and railroads in areas with poor soil conditions, these areas are often improved by means of foundation engineering. Constructions that are fairly limited in scope are often founded on shallow or deep foundations. However, these methods are relatively expensive and thus not applicable for large-scale constructions like roads and railroads. A cost-effective way to deal with poor soil conditions is to use ground improvement. This thesis deals with a ground improvement method called deep mixing (DD)using lime-cement columns. Lime-cement columns are manufactured by pushing a mechanical mixing tool to the desired depth, with the tool then rotated and retracted while a lime-cement binder is distributed into soil, forming lime-cement columns. Because of the complex mixing process and inherent soil variability, soil improved by DD shows high variability with respect to strength and deformation properties. Due to this high variability, it is difficult to predict the properties in advance; it is therefore important to verify the properties after installation. In Sweden, this is normally done using the column penetration test (KKK) method. Current design praxis considers evaluated mean values in the design, and the effect of variability and uncertainties is dealt with by using a sufficiently high total factor of safety. A more rational approach for dealing with the effect of variability and uncertainties on the reliability of a mechanical system is to include them as parameters in the design model. This can be done by using reliability-based design (RRR). A major incentive for using 𝑅𝑅𝑅 is that lower variability in design properties produces higher design values. This is important since it encourages contractors to improve their manufacturing methodologies because 𝑅𝑅𝑅 allows more homogenous columns to be assigned higher design values. Reliability-based design is also in line with Eurocode 7, which states that the selection of the characteristic values for geotechnical parameters shall take the variability of the measured property values into account. The first part of this doctoral thesis deals with test methods and quantification of the strength variability of soil improved by lime-cement columns. Tip resistances from three different test sites using three different penetration test methods – the cone penetration test, the column penetration test and the total-sounding test – are analysed and quantified in terms of means, variances and scale of fluctuations. The second part introduces RRR in serviceability limit state (SSS) design, using First Order Reliability Methods (FFFF) and Monte-Carlo simulations. Summarizing the most important findings and conclusions from this study: The scale of fluctuation was estimated to be 0.2-0.7 m and 0-3 m in the vertical and horizontal direction, respectively. The relation between cone tip resistances measured using the cone penetration test and column penetration test does not correspond to the cone factors proposed in previous studies and in the Swedish Design Guidelines. The agreement between the column penetration test and total-sounding test was found to be “good enough”. It is therefore suggested that the total-sounding test be used as a complement to the column penetration test in evaluating the average strength properties of a group of medium- and high-strength lime-cement columns. Reliability-based design is a rational approach to incorporate strength and deformation parameter variability with an SSS design.QC 20150605
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Thomas, Timothy William. "Assessment of the mixing state and cloud nucleating efficiency of Asian aerosols using aircraft-based measurements of hygroscopicity." Thesis, Texas A&M University, 2003. http://hdl.handle.net/1969.1/3980.
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Global warming theories continue to overestimate their predictions of increased mean global temperatures (Hudson 1991). This would imply that some other influence is counteracting the global warming influences; i.e. a cooling effect. Cloud albedo characteristics are currently being researched to determine the impact clouds have on the net cooling of the atmosphere in relation to the global warming theory. These characteristics are influenced by the type, size, composition, and abundance of aerosol particles that act as cloud condensation nuclei. This study employs Tandem Differential Mobility Analyzer (TDMA) data collected in the vicinity of Japan during the Asian Aerosol Characterization Experiment (ACE-Asia) to investigate the influence of aerosol concentration and composition on the light scattering properties of clouds. Measurements of particle size (Dp), particle growth factor (GF), and relative humidity (RH) yield critical supersaturations (Sc) with the assumption that the soluble part of the particle is composed primarily of one substance. This indirect composition analysis allows us to determine whether the aerosol was internally mixed (particles have uniform composition and yield a single-peak distribution or similar growth factors) or externally mixed (different particles have different compositions yielding multiple peaks in the distribution). Through the use of calculated supersaturations, we can gain insight into cloud droplet activation properties of the samples for various aerosol types, which ultimately allows us to look at the influence of these particles on albedo characteristics of clouds formed by these particles.
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Al-Omar, Reem S. "Cancer incidence in young people in Saudi Arabia : relation to socioeconomic status and population mixing." Thesis, University of Leeds, 2015. http://etheses.whiterose.ac.uk/8948/.
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This study describes cancer incidence in under 24 year olds, particularly leukaemias, lymphomas and central nervous system tumours. It also describes the socioeconomic status (SES) of the geographically delimited Governorates in Saudi Arabia, by deriving two indices – the first time this has been done in the country. It also sought to determine whether SES and Hajj (occurring in Makkah) as a measure of population mixing has an association with the incidence of these cancers. During 1994 to 2008, 17,150 cases were identified from the Saudi Cancer Registry. Census data were accessed for 2004 and included 29 indicators. A continuous SES index was constructed using exploratory factor analysis (EFA) and a categorical index using latent class analysis (LCA). Incidence rate ratios (IRRs) were calculated for cancers in Makkah compared to other Governorates by year to assess the effect of Hajj, and for all Governorates to assess the effect of SES. The Hajj had no significant effect on the incidence for all cancer groups. The continuous index produced by EFA consisted of scores ranging from 100 to 0, for affluent to deprived Governorates. The LCA found a four-class model as the best model fit. Class 1 was termed ‘affluent’, Class 2 ‘upper-middle’, Class 3 ‘lower-middle’ and Class 4 ‘deprived’. The urbanised Governorates were affluent, whereas the rural Governorates were on average more deprived. For SES, an elevated risk was found for acute lymphoblastic leukaemia in the affluent class (IRR=1.38, 95%CI=1.23-1.54), and was reduced in the deprived class (IRR=0.17, 95%CI=0.10-0.29). Similar associations were observed for all cancer groups. The findings are not supportive of the PM hypothesis, but give support to the delayed infection hypothesis, suggesting that delayed exposure to infections may prevent immune system modulation, although results may be exacerbated by poor case-ascertainment/under-diagnosis in deprived areas. Similarities between the two indices suggest validity.
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Vettese, Carlo Ettore. "The effects of multi-quantum well inter-mixing on long-wavelength opto-electronic structures and devices." Thesis, University of Nottingham, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387226.
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Manathunga, Madushanka. "Impact of Electronic State Mixing on the Photoisomerization Timescale of Natural and Synthetic Molecular Systems." Bowling Green State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1541548724939953.
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Pratt, Kerri Anne. "New insights into single-particle mixing state using aircraft aerosol time-of-flight mass spectrometry." Diss., [La Jolla] : University of California, San Diego, 2009. http://wwwlib.umi.com/cr/ucsd/fullcit?p3372559.
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Thesis (Ph. D.)--University of California, San Diego, 2009.Title from first page of PDF file (viewed Oct. 7, 2009). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references.
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Lin, Xiaodan, and 林曉丹. "Morphology and structure development of a PET/PP blend in extrusion, solid-state drawing and annealing." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B31240598.
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Sylvia, Stephen F. "Effects of physiological state, temperature, water, and extended mixing on low-fat, high-added water frankfurters." Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-09042008-063636/.
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Mishchenko, Yuriy. "Applications of canonical transformations and nontrivial vacuum solutions to flavor mixing and critical phenomena in quantum field theory." NCSU, 2004. http://www.lib.ncsu.edu/theses/available/etd-10312004-202935/.
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This dissertation deals with recent applications of Bogoliubov transformation to the phenomenology of quantum flavor mixing and to the study of critical phenomena in quantum field theories. The dissertation contains a brief review of canonical transformations, with a special emphasis on linear quantum canonical transformation (Bogoliubov transformation), as they appear in classical and quantum physics and their applications in superfluidity and low energy quantum chromodynamics (QCD). Then, the general quantum field theory of flavor mixing is introduced with Bogoliubov transformation, space-time conversion is considered and effects for phenomenology of flavor oscillations in time and space is presented. Furthermore, the Oscillator Representation Method, relevant to analysis of degrees-of-freedom rearrangement during phase transitions, is fully reviewed and illustrated. Nontrivial vacuum condensation, dynamical mass generation and duality are all incorporated as parts of this approach. Specific applications to phase transition in nonlinear sigma model and phi^4 scalar quantum field theory are presented and possibilities for further method improvement are considered. A new independent variational approach, method of Symmetric Decomposition Problem, is also fully introduced, illustrated and applied to the analysis of the ground state in a variant of nonlinear sigma model. In this method, the structure of the Fock space in terms of the expectation values of given quantum operators is found and used to reformulate and exactly solve variational problem for the ground state of the above mentioned quantum field theory.
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Rogalski, Joachim. "Föredras ljudbilden från Neve eller Solid State Logic? : Lyssnarpreferenser av emulering vid mixning." Thesis, Mittuniversitetet, Institutionen för elektronikkonstruktion, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-41706.
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2:1 Bakgrunden och problemet Upplever lyssnaren någon skillnad om en låt har spelats in identiskt, mixats med samma förutsättningar gällande rumsklang och övriga effekter, men med två olika mixerbordsemuleringar? De två största plattformarna Neve och deras bord 88RS, samt SSL och deras bord 4000 E, har jämförts i en undersökning av lyssnarupplevelsen.För att kunna få ett oberoende och jämförbart resultat, komponerades en ny låt för ändamålet där projektet spelades in så att alla tagningar blev identiska för båda plattformarna. Låten summerades analogt, men med en så opåverkad signal som tänkbart. Mixen skulle i nivåer för de olika kanalerna likna varandra så mycket som möjligt och detta även i rumsklang, panorering och upplevt ljudtryck. Musiken mastrades så att kvaliteten skulle vara så lika så att inte lyssnare reagerade på detta, samt att uppfattningen av ljudvolym inte skilde de olika versionerna åt. 2.2 Undersökningen Först planerades att intervjua ca 20 deltagare men då vår verklighet såg ut som den gjorde med sociala restriktioner, så gjordes undersökningen om till en enkät med en utförandebeskrivning och frågor. Även beskrivande ord användes för att se om lyssnaren kunde uppfatta eller associera med de olika versionerna. Undersökningen distribuerades sen till en blandad demografisk grupp där ungefär hälften utgjorde erfarna musiker och den andra hälften erfarna lyssnare. Sammanlagt så gjorde 30 personer undersökningen. Ingen av lyssnarna visste vilken version som var mixad på vilken av de två olika plattformarna. 2.3 Resultatet 96,7% upplevde en skillnad där 86,7% föredrog version ”B” som var emuleringen av Neves 88RS (även Universal Audio Neve 1073, och Plug in Alliance, Lindell 80 Serie, Neve klon). Båda mixarna ansågs låta professionella och det som normalt förknippas med de två plattformarna visade sig även beskrivas i kommentarerna. ”A” ansågs av vissa ha ett mera ”modernt” sound även där man föredrog ”B” mot slutet av lyssningarna. ”B” ansågs vara mera mjukt och inbjudande för lyssnaren och förknippades mycket mer med den bild som musiken ansågs förmedla. Skillnaden upplevdes dock som subtil av en stor majoritet och några av lyssnarna påpekade att med tid emellan lyssningarna skulle man inte urskilja vad som var vad. 2.4 Slutsatsen Jag blev förvånad att det inte blev mera uppdelat. Själv har jag under projektet föredragit ”A” då den ljudbilden påminner mig mer om det jag själv gillar historiskt. Men jag håller med att det är subtilt. Det finns aspekter med testet som inte skall förringas. Kan man emulera så bra idag att det duger till ett sådant här test? Absolut om man skall tro företagen som låter digitala emuleringar få flagga med deras namn. Är en hybrid av båda plattformarna att föredra då ”B” ansågs ha mest fördelar gällande hur sången uppfattades? Är det värt att investera i båda plattformarna? Enligt det här resultatet så hade det räckt med Neve-emuleringarna när det gäller den här typen av musikgenre.
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Kölle, Andreas [Verfasser]. "Coherent Phenomena in Four-Wave Mixing via a Rydberg State in Thermal Vapor of Rubidium / Andreas Kölle." München : Verlag Dr. Hut, 2015. http://d-nb.info/106770809X/34.
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Namboodiri, Vinu V. [Verfasser]. "Femtosecond Time-Resolved Four-Wave Mixing Applied to the Investigation of Excited State Dynamics / Vinu V. Namboodiri." Bremen : IRC-Library, Information Resource Center der Jacobs University Bremen, 2010. http://d-nb.info/1035033917/34.
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Herwig, Falk. "Evolution of late stages of intermediate mass stars : mixing processes and their consequences for stellar evolution and nucleosynthesis /." Aachen : Shaker, 1998. http://catalogue.bnf.fr/ark:/12148/cb37322724p.
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Texte traduit de: Dissertation--Mathematisch-Naturwissenschaftliche Fakultät--Kiel--Christian-Albrechts-Universität, 1998. Titre de soutenance : Spätphasen der Entwicklung von Sternen mittlerer Masse : Mischprozesse und ihre Bedeutung für Sternentwicklung und Elementsynthese.
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Boeri, Marco. "Advances in stated preference methods : discrete and continuous mixing distributions in logit models for representing variance and taste heterogeneity." Thesis, Queen's University Belfast, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.554305.
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This thesis is a collection of four papers; one centred on a policy application of Contingent Valuation (CV) and three essays focused on econometric advances in Discrete Choice Experiments (DCE). The former paper represents the first attempt to appraise odour externalities in an urban context employing DBCV. The survey was administered to a sample of 1000 households in Le Havre (France). Results reveal a positive WTP for eliminating odour externalities which vary across areas, respondent characteristics and perceptions. The potential of latent class analysis in DCE is explored in the latter three papers. The PhD has been mainly focused on developing new tools for accommodating heterogeneity in tastes, variances and heuristics employing latent class (LC) analysis. As a result I formalised a type of LC models that can accommodate for heteroscedasticity and/or heterogeneity (depending on assumptions and parameterisation) within class as well as different heuristics across classes. More specifically the second paper introduces class heterogeneity within a LC model, which is obtained by specifying a discrete mixture of sets of continuous distributions. The model is applied to both simulated and real data in order to demonstrate its flexibility and the advantages for policy appraisal. The third paper introduces and formalises the idea of a heteroscedastic LC model using data from two recreational site choice studies (one elicited through stated preference methods and one through revealed preference methods) to compare various model specifications. In the fourth and final paper, the well known problem of preference and variance instability due to learning and fatigue in DCE is tackled by applying a scale-adjusted latent class model to uncover both types of instability simultaneously and probabilistically across the sample. Findings highlight the advantages in terms of model fit, interpretation and policy implications, that can be achieved when both types of instability are addressed concurrently.
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Schliesser, Jacob M. "Development and Application of New Solid-State Models for Low-Energy Vibrations, Lattice Defects, Entropies of Mixing, and Magnetic Properties." BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/5841.
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Low-temperature heat capacity data contain information on the physical properties of materials, and new models continue to be developed to aid in the analysis and interpretation of heat capacity data into physically meaningful properties. This work presents the development of two such models and their application to real material systems. Equations describing low-energy vibrational modes with a gap in the density of states (DOS) have been derived and tested on several material systems with known gaps in the DOS, and the origins of such gaps in the DOS are presented. Lattice vacancies have been shown to produce a two-level system that can be modeled with a sum of low-energy Schottky anomalies that produce an overall linear dependence on temperature in the low-temperature heat capacity data. These two models for gaps in the vibrational DOS and the relationship between a linear heat capacity and lattice vacancies and many well-known models have been applied to several systems of materials to test their validity and applicability as well as provide greater information on the systems themselves. A series of bulk and nanoscale Mn-Fe and Co-Fe spinel solid solutions were analyzed using the entropies derived from heat capacity data, and excess entropies of mixing were determined. These entropies show that changes in valence, cation distribution, bonding, and the microstructure between the mixing ions is non-ideal, especially in the nanoparticles. The heat capacity data of ten Al doped TiO2 anatase nanoparticle samples have also been analyzed to show that the Al3+ dopant ions form small regions of short-range order, similar to a glass, within the TiO2 particles, while the overall structure of TiO2 remains unchanged. This has been supported by X-ray diffraction (XRD) and electron energy-loss spectroscopy and provides new insights to the synthesis and characterization of doped materials. The final investigation examines nanocrystalline CuO using heat capacities, magnetization, XRD, and electron microscopy and compares the findings to the known properties of bulk CuO. All of these measurements show transitions between antiferromagnetic and paramagnetic states in the temperature range of about 150-350 K that are greater in number and higher in temperature than the transitions in bulk CuO. These changes are shown to cause an increase in the temperature range of multiferroicity in CuO nanoparticles.
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Banerjee, Chitram. "Experimental and Theoretical Study of Two Non-linear Processes Induced by Ultra-narrow Resonances in Atoms." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS139/document.
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Dans ce travail de thèse, je considère deux phénomènes distincts, tous deux liés aux interactions non-linéaires entre la lumière et des atomes. La première partie est dédiée à du mélange à 4 ondes basé sur des degrés de liberté internes d’atomes d’hélium à température ambiante, et l’utilise pour des processus d’amplification et de la génération d’états comprimés. Le second phénomène étudié est basé sur des degrés de liberté externes d’atomes de césium froids et est utilisé pour du stockage de lumière et la génération d’un champ conjugué en phase par mélange d’ondes. J'ai expérimentalement observé et caractérisé de l'amplification sensible à la phase par mélange à quatre ondes dans de l'hélium métastable à température ambiante. J'ai obtenu un gain maximum d'environ 9 dB avec une bande passante d'environ 300 kHz. Les fonctions de transfert phase/phase obtenues ont montré une forte compression de phase, indiquant que le phénomène était presque exempt de processus indésirables. Dans la seconde partie, j'explique comment les résonances de recul, dues à un transfert de quantité de mouvement entre un photon et un atome, peuvent être utilisées pour du stockage de lumière. J'explique également comment ce phénomène peut conduire à la génération d’un champ conjugué, et pourquoi la théorie existante ne permet pas de modéliser le creux qui apparaît dans le spectre de génération du champ conjugué lorsqu’on augmente la puissance optique. Pour reproduire ce nouvel élément, j’ai effectué un développement jusqu’au 5e ordre, qui démontre qu’il dépend de la cohérence qui est excitée entre des niveaux de moments atomiques différents. Je montre ensuite qu'un modèle plus simple, basé sur trois niveaux atomiques définis par des degrés de liberté interne et externe de l'atome, peut expliquer le phénomène observéIn this PhD work, two distinct phenomena are considered, which are both related to non-linear interactions between light and atoms. The first part of the thesis is dedicated to four wave mixing based on the internal degrees of freedom of room temperature helium atoms and uses it for amplification processes and generation of squeezed light. The second studied process is based on external degrees of freedom of cold cesium atoms and used for light storage and phase conjugate field generation through multi-wave mixing. I experimentally observed and characterized phase sensitive amplification via four-wave mixing in metastable helium at room temperature. I have obtained about 9 dB of maximum gain with a bandwidth of about 300 kHz. The obtained phase transfer functions showed a strong phase squeezing, indicating that the phenomenon was almost free of unwanted processes. In the second part, I explain how recoil induced resonances, which are due to the transfer of momentum between a photon and an atom, can be used to store light. I also explain how this phenomenon can lead to generation of a phase conjugate field, and why the existing theory fails to model the dip, which appears in the phase conjugate generation spectrum when the field power is increased. I extend the model to the fifth order so that it can reproduce this new feature and demonstrate that it depends on the decay rate of the coherence, which is excited between atomic levels of different momenta. I then show that a simpler model, which is based on three levels defined by internal and external degrees of freedom of the atom, can explain the observed phenomenon
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Yates, James William. "Mixing Staged Data Flow and Stream Computing Techniques in Modern Telemetry Data Acquisition/Processing Architectures." International Foundation for Telemetering, 1999. http://hdl.handle.net/10150/608707.
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International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, NevadaToday’s flight test processing systems must handle many more complex data formats than just the PCM and analog FM data streams of yesterday. Many flight test programs, and their respective test facilities, are looking to leverage their computing assets across multiple customers and programs. Typically, these complex programs require the ability to handle video, packet, and avionics bus data in real time, in addition to handling the more traditional PCM format. Current and future telemetry processing systems must have an architecture that will support the acquisition and processing of these varied data streams. This paper describes various architectural designs of both staged data flow and stream computing architectures, including current and future implementations. Processor types, bus design, and the effects of varying data types, including PCM, video, and packet telemetry, will be discussed.
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Siepka, Damian. "Development of multidimensional spectral data processing procedures for analysis of composition and mixing state of aerosol particles by Raman and FTIR spectroscopy." Thesis, Lille 1, 2017. http://www.theses.fr/2017LIL10188/document.
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Les méthodologies de traitement de données multidimensionnelles peuvent considérablement améliorer la connaissance des échantillons. Les techniques spectroscopiques permettent l’analyse moléculaire avancée d’échantillons variés et complexes. La combinaison des techniques spectroscopiques aux méthodes de chimiométrie trouve des applications dans de nombreux domaines. Les particules atmosphériques affectent la qualité de l’air, la santé humaine, les écosystèmes et jouent un rôle important dans le processus de changement climatique. L’objectif de cette thèse a été de développer des outils de chimiométrie, simples d’utilisation, permettant de traiter un grand nombre de données spectrales provenant de l’analyse d’échantillons complexes par microspectrométrie Raman (RMS) et spectroscopie d’absorption IRTF. Dans un premier temps, nous avons développé une méthodologie combinant les méthodes de résolution de courbes et d’analyse multivariée afin de déterminer la composition chimique d’échantillons de particules analysées par RMS. Cette méthode appliquée à l’analyse de particules collectées dans les mines en Bolivie, a ouvert une nouvelle voie de description des échantillons. Dans un second temps, nous avons conçu un logiciel facilement accessible pour le traitement des données IRTF et Raman. Ce logiciel inclue plusieurs algorithmes de prétraitement ainsi que les méthodes d’analyse multivariées adaptées à la spectroscopie vibrationnelle. Il a été appliqué avec succès pour le traitement de données spectrales enregistrées pour divers échantillons (particules de mines de charbon, particules biogéniques, pigments organiques)Sufficiently adjusted, multivariate data processing methods and procedures can significantly improve the process for obtaining knowledge of a sample composition. Spectroscopic techniques have capabilities for fast analysis of various samples and were developed for research and industrial purposes. It creates a great possibility for advanced molecular analysis of complex samples, such as atmospheric aerosols. Airborne particles affect air quality, human health, ecosystem condition and play an important role in the Earth’s climate system. The purpose of this thesis is twofold. On an analytical level, the functional algorithm for evaluation of quantitative composition of atmospheric particles from measurements of individual particles by Raman microspectrocopy (RMS) was established. On a constructive level, the readily accessible analytical system for Raman and FTIR data processing was developed. A potential of a single particle analysis by RMS has been exploited by an application of the designed analytical algorithm based on a combination between a multicurve resolution and a multivariate data treatment for an efficient description of chemical mixing of aerosol particles. The algorithm was applied to the particles collected in a copper mine in Bolivia and provides a new way of a sample description. The new user-friendly software, which includes pre-treatment algorithms and several easy-to access, common multivariate data treatments, is equipped with a graphical interface. The created software was applied to some challenging aspects of a pattern recognition in the scope of Raman and FTIR spectroscopy for coal mine particles, biogenic particles and organic pigments
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Wilson, Raymond Gary. "A Numerical Analysis of the Influence of Korteweg Stresses on the Flow and Mixing of Miscible Fluids." Cleveland, Ohio : Case Western Reserve University, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=case1081283678.
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Thesis (Ph.D.)--Case Western Reserve University, 2004Title from PDF (viewed on 01 October 2009) Department of Mechanical Engineering Includes abstract Includes bibliographical references Available online via the OhioLINK ETD Center
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Unga, Florin. "Investigation of atmospheric aerosol mixing state effect on measured and retrieved optical characteristics : an approach integrating individual particle analysis, remote sensing and numerical simulations." Thesis, Lille 1, 2017. http://www.theses.fr/2017LIL10023/document.
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Les aérosols troposphériques influencent la composition chimique de l’atmosphère, le bilan radiatif terrestre et le climat. Après formation, les aérosols subissent des processus de vieillissement altérant leurs propriétés microphysiques et chimiques. L’étude de l’impact environnemental des aérosols à différentes échelles spatio-temporelles doit donc tenir compte des transformations physico-chimiques. Les objectifs poursuivis sont : (i) d’étudier par microscopie analytique électronique à balayage et en transmission la composition élémentaire et l'état de mélange des particules atmosphériques prélevées lors d'épisodes de charge élevée en aérosol ; (ii) d’analyser les effets des propriétés microphysiques sur les caractéristiques optiques mesurées et restituées par télédétection ; (iii) de proposer un paramétrage ainsi qu’une représentation de la composition et de la structure des particules dans les algorithmes de télédétection. Ces travaux portent sur des observations dans le Nord de la France et en Afrique de l’Ouest (Sénégal) dans le cadre du Labex CaPPA et des campagnes de terrain SHADOW. Sont inclues des analyses complémentaires de la composition chimique et de la structure de particules individuelles, de mesures in situ et par télédétection de particules urbano-industrielles, désertiques et de biomasse prélevées en surface et à différentes altitudes. Une série de simulations numériques ont été utilisées dans le but d'analyser la sensibilité des observations par télédétection à l’état de mélange des aérosols. Enfin, l'intégration d'un paramétrage de la structure en "core-shell" des particules dans les algorithmes de restitution est présentée en perspectiveTropospheric aerosols play an important role in atmospheric chemistry, Earth’s radiative budget and climate. After their generation, aerosol can suffer ageing processes and altering their physicochemical properties. An accurate accounting for these processes requires observations of the aerosol properties on different temporal and spatial scales. The current thesis work is dedicated to: (i) study of physicochemical properties and mixing state of individual particles by means of analytical scanning and transmission electron microscopy for aerosols collected during episodes of elevated aerosol loading; (ii) analysis of the effect of microphysical properties on optical characteristics as measured and retrieved by remote sensing; and (iii) investigation of possible parameterization of aerosol composition and structure in remote sensing algorithms. The work presents observations conducted in northern France and western Africa (Senegal) as part of Labex CaPPA project and SHADOW field campaigns. It includes simultaneous analyses of collected individual particles composition and structure, remote sensing and in situ observations of urban/industrial, Saharan dust and biomass burning particles near the surface and on different altitudes. A series of numerical simulation devoted to an analysis of sensitivity of remote sensing observations to aerosol mixing state is conducted. Insights on possible parameterization of aerosol core-shell structure in retrieval algorithms are finally presented
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Meddour, Athmane. "Structure electronique d'alliages metalliques amorphes et quasicristallins : systemes binaires pdy et almn." Paris 6, 1988. http://www.theses.fr/1988PA066696.
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Etude realisee par spectroscopie optique et photoelectronique. Les echantillons sont prepares par pulverisation cathodique sous forme de couches minces. On obtient des echantillons amorphes et quasicristallins par melange ionique a partir de couches multiples. Discussion de l'evolution des spectres optiques des alliages al-mn lorsqu'on passe d'un etat cristallin ordonne a un etat quasi ordonne et enfin a un etat totalement desordonne
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Moore, Richard Herbert. "Using measurements of CCN activity to characterize the mixing state, chemical composition, and droplet growth kinetics of atmospheric aerosols to constrain the aerosol indirect effect." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/45945.
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Atmospheric aerosols are known to exert a significant influence on the Earth's climate system; however, the magnitude of this influence is highly uncertain because of the complex interaction between aerosols and water vapor to form clouds. Toward reducing this uncertainty, this dissertation outlines a series of laboratory and in-situ field measurements, instrument technique development, and model simulations designed to characterize the ability of aerosols to act as cloud condensation nuclei (CCN) and form cloud droplets. Specifically, we empirically quantify the mixing state and thermodynamic properties of organic aerosols (e.g., hygroscopicity and droplet condensational uptake coefficient) measured in polluted and non-polluted environments including Alaska, California, and Georgia. It is shown that organic aerosols comprise a substantial portion of the aerosol mass and are often water soluble. CCN measurements are compared to predictions from theory in order to determine the error associated with simplified composition and mixing state assumptions employed by current large-scale models, and these errors are used to constrain the uncertainty of global and regional cloud droplet number and albedo using a recently-developed cloud droplet parameterization adjoint coupled with the GMI chemical transport model. These sensitivities are important because they describe the main determinants of climate forcing. We also present two novel techniques for fast measurements of CCN concentrations with high size, supersaturation, and temporal resolution that substantially improve the state of the art by several orders of magnitude. Ultimately, this work represents a step toward better understanding how atmospheric aerosols influence cloud properties and Earth's climate.
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Staudt, Paula Bettio. "Nova equação cúbica de estado para a predição do equilíbrio líquido-vapor de misturas complexas envolvendo polímeros e óleos." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2010. http://hdl.handle.net/10183/30140.
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Neste trabalho uma nova equação cúbica de estado é proposta baseada no princípio de superposição temperatura-pressão. A equação trata de novas expressões para a determinação dos termos atrativo e co-volume sem dependência de propriedades críticas, podendo ser aplicada a qualquer forma cúbica. Neste estudo foi associada aos parâmetros da equação de Peng-Robinson e é chamada aqui de PR-S. A predição do comportamento pressão-volume-temperatura (PVT) de polímeros puros e o equilíbrio líquidovapor (VLE) de soluções poliméricas foram avaliados. Os resultados se mostraram muito bons quando comparados a dados experimentais. Com base no bom desempenho da nova equação, expandiu-se a aplicação da PR-S para a predição de VLE de misturas envolvendo biodiesel. Para os sistemas estudados a PR-S apresentou uma boa capacidade preditiva frente a outras alternativas, aproximando sua resposta aos dados reais sem a necessidade de ajustes experimentais. Por fim, foi realizado um estudo preliminar de aplicação da equação proposta para sistemas de óleos vegetais com solventes supercríticos. Algumas dificuldades foram encontradas principalmente decorrentes da caracterização dos mesmos através de um único pseudocomponente. Os resultados foram promissores e servirão como base para futuros desenvolvimentos, uma vez que na literatura a maioria dos trabalhos a cerca de misturas de óleos vegetais faz uso de parâmetros de interação binária abrindo mão de modelos puramente preditivos.In this work a new cubic equation of state (CEOS) is proposed based on the temperaturepressure superposition principle. Called here as PR-S, it has a generic CEOS form with the Peng-Robinson parameters. A temperature-dependent attractive term a(T) is developed along with a new covolume expression, allowing an easy calculation of thermodynamic properties and vapor-liquid equilibrium. Firstly, the new equation was applied to pure polymer and polymer solutions and its results were compared with those of other equations of state and with experimental data. The PR-S equation was also applied to predict the vapor-liquid equilibrium (VLE) of biodiesel related systems and vegetable oils with supercritical solvent mixtures. The results of VLE predictions for polymer and biodiesel systems showed good agreement with experimental data as well as the pressure-volume-temperature (PVT) behavior of pure polymer liquids, attesting the appropriate form of the new equation proposed. For the vegetable oil systems the initial study showed some difficulties raised from the poor caracterization of oils as pseudocomponents. Despite this fact the first outcome was satisfying once there is no work in literature using predictive tools for these kind of mixtures with success.
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Fraund, Matthew. "Developing X-ray Spectromicroscopic Techniques to Quantitatively Determine Population Statistics and Individual Particle Composition of Complex Mixed Aerosols." Scholarly Commons, 2019. https://scholarlycommons.pacific.edu/uop_etds/3622.
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Aerosols are a major source of uncertainty in estimates of anthropogenic effects on global radiative forcing and can pose serious health concerns. While many instrumental techniques capable of analyzing aerosol samples are available, individual-particle spectromicroscopic techniques like the ones presented here are the only ones to offer morphological and compositional measurements together. Studying the composition and mixing state of aerosol populations allowed for important aspects to be uncovered, such as: aerosol source, formation mechanism, hygroscopicity, optical properties, level of aging, and inhalation dangers. Ambient aerosols from the Amazon, both biogenic and anthropogenic, were apportioned based on their individual composition. Recently discovered organic aerosols from the central United States were identified and their chemical properties were characterized. The lead fraction of mixed lead- and zinc-rich particles from Mexico City was speciated to determine the lead’s solubility and possible bioavailability. It is through the use of these powerful spectromicroscopic techniques that a better understanding of complex mixed aerosols was achieved.
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Anderson, Sheri L. "Status & solidarity through codeswitching: three plays by Dolores Prida." Thesis, Texas A&M University, 2004. http://hdl.handle.net/1969.1/536.
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This analysis employs the sociolinguistic framework of status and solidarity (Holmes, 2001) to examine the use of codeswitching on the relational development between the characters in three plays by Cuban-American playwright Dolores Prida. The three plays discussed are Beautiful Señoritas (1978), Coser y cantar (1981) and Botánica (1991). Linguistic scholars recognize the lack of linguistic analysis of literary texts; specifically, codeswitching at present is not fully explored as a linguistic phenomenon in written contexts. Furthermore, Prida's works have never before been appraised using linguistic methodology. Hence, this work aims to add to scholarly research in the fields of codeswitching, discourse analysis, and literary linguistics, using the status and solidarity framework to examine the codeswitching in Dolores Prida's plays. Dolores Prida is a feminist and Hispanic dramatist whose central theme is the search for identity of Hispanic immigrants, specifically women, in the United States today. Due to her ideological stance, it is expected that a strong emphasis on solidarity rather than status and the use of affective rather than referential speech functions are present in the relationships in her plays. Accordingly, the analysis of Botánica reveals that indeed codeswitching between the characters does affect their relational development in maintaining solidarity and intimacy. However, the relationships found in Beautiful Señoritas and Coser y cantar do not offer such conclusions, due to the variable nature of the relationships identified. Further analysis of these and other literary works will more accurately determine benefits of the status and solidarity framework as applied to the codeswitching research.
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Hultin, Kim. "Primary Marine Aerosol Production : Studies using bubble-bursting experiments." Doctoral thesis, Stockholms universitet, Institutionen för tillämpad miljövetenskap (ITM), 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-43544.
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Aerosol particles affect the Earth’s climate, although their impact is associated with large uncertainties. Primary marine aerosol represents a significant fraction of the global aerosol budget considering the Earth’s 70-percentage coverage by oceans. They are produced when bubbles burst at the ocean surface and can consist of sea salt, organic matter and bacteria. An experimental approach was here used to investigate the primary marine aerosol production from the bubble-bursting mechanism using water from four different geographical locations. The main findings include: Similar and stable aerosol number size distributions at all locations, centered close to 0.2 μm. Largely varying aerosol organic fractions, both with size and location. Clear tendency for increased water temperature to negatively influence the aerosol production. No covariance between surface water chlorophyll α and aerosol production on a 10-minute time scale, although decreased aerosol production was observed at times of elevated phytoplankton activity on longer time scales. Mainly external mixtures of sea salt and organics was observed. A high tendency for colony-forming marine bacteria to use bubble-bursting to reach the atmosphere. A clear diurnal cycle in aerosol production was found for both laboratory produced aerosol and in-situ aerosol fluxes, probably biologically driven. The first near coastal sea spray fluxes with limited fetch and low salinity. While the primary marine aerosol spectral shape is stable, emission concentration varies with environmental parameters. Above that, the organic fraction of the aerosol varies largely between locations. This shows that observations of primary marine aerosol emissions not necessarily can be applied to large time- or spatial scales.At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: In press. Paper 3: Manuscript. Paper 4: Manuscript.
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Cross, Eben Spencer. "Sources and transformations of atmospheric aerosol particles." Thesis, Boston College, 2008. http://hdl.handle.net/2345/971.
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Thesis advisor: Paul DavidovitsAerosol particles are an important component of the Earth-Atmosphere system because of their influence on the radiation budget both directly (through absorption and scattering) and indirectly (through cloud condensation nuclei (CCN) activity). The magnitude of the raditaive forcing attributed to the direct and indirect aerosol effects is highly uncertain, leading to large uncertainties in projections of global climate change. Real-time measurements of aerosol properties are a critical step toward constraining the uncertainties in current global climate modeling and understanding the influence that anthropogenic activities have on the climate. The objective of the work presented in this thesis is to gain a more complete understanding of the atmospheric transformations of aerosol particles and how such transformations influence the direct and indirect radiative effects of the particles. The work focuses on real-time measurements of aerosol particles made with the Aerodyne Aerosol Mass Spectrometer (AMS) developed in collaboration with the Boston College research group. A key feature of the work described is the development of a lightscattering module for the AMS. Here we present the first results obtained with the integrated light scattering – AMS system. The unique and powerful capabilities of this new instrument combination are demonstrated through laboratory experiments and field deployments. Results from two field studies are presented: (1) The Northeast Air Quality Study (NEAQS), in the summer of 2004, conducted at Chebogue Point, Nova Scotia and (2) The Megacity Initiative: Local and Global Research Observations (MILAGRO) field campaign conducted in and around Mexico City, Mexico in March of 2006. Both field studies were designed to study the transformations that occur within pollution plumes as they are transported throughout the atmosphere. During the NEAQS campaign, the pollution plume from the Northeastern United States was intercepted as it was transported towards Europe. In this study, particles were highly processed prior to sampling, with residence times of a few days in the atmosphere. The MILAGRO campaign focused on the evolution of the Mexico City plume as it was transported north. During this study, regional and locally emitted particles were measured with residence times varying from minutes to days in the atmosphere. In both studies, the light scattering – AMS system provided detailed information about the density and composition of single particles, leading to important insights into how atmospheric processing transforms the particle properties. In Mexico City, the light scattering-AMS system was used for the first time as a true single particle mass spectrometer and revealed specific details about the atmospheric processing of primary particles from combustion sources.To quantify the radiative effects of the particles on climate, the processing and ultimate fate of primary emissions (often containing black carbon or soot) must be understood. To provide a solid basis for the interpretation of the data obtained during the field studies, experiments were conducted with a well characterized soot generation-sampling system developed by the Boston College research group. The laboratory soot source was combined with the light scattering – AMS system and a Cloud Condensation Nuclei Counter (CCNC) to measure the change in cloud-forming activity of soot particles as they are processed in the atmosphere. Because of the importance of black carbon in the atmosphere, several instruments have been developed to measure black carbon. In July of 2008, an intercomparison study of 18 instruments was conducted in the Boston College laboratory, with soot particles produced and processed to mimic a wide range of atmospherically-relevant conditions. Transformations in the physical, chemical, and optical properties of soot particles were monitored with the combined suite of aerosol instrumentation. Results from the intercomparison study not only calibrated the different instruments used in the study, but also provided critical details about how atmospheric processing influences the radiative effects of primary combustion particles
Thesis (PhD) — Boston College, 2008
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Chemistry
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Eyi-Minko, Frédéric. "Propriétés des processus max-stables : théorèmes limites, lois conditionnelles et mélange fort." Thesis, Poitiers, 2013. http://www.theses.fr/2013POIT2282/document.
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Le thème de cette thèse est la théorie spatiale des valeurs extrêmes, et les objets principalement étudiés sont les processus max-stables à trajectoires continues. Nous commençons par déterminer la convergence des maximums de processus stochastiques indépendants, en utilisant la convergence de mesures empiriques vers des processus ponctuels de Poisson. Ensuite, nous déterminons les lois conditionnelles des processus max infiniment divisibles (max-i.d). La représentation des processus max-i.d par des processus ponctuels de Poisson permet l'introduction de notions telles que les fonctions extrémales et le hitting scénario qui permettent d'aboutir au résultat. Les processus max-stables étant des processus max-i.d, nous proposons un algorithme de simulation conditionnelle pour les champs max-stables puis nous l'utilisons pour des applications avec des données de précipitations autour de Zurich et de températures en Suisse. Nous trouvons aussi, une majoration du coefficient de β-mélange entre les restrictions d'un processus max-i.d sur deux sous-ensembles fermés et disjoints d'un espace métrique localement compact. Cette majoration permet d'obtenir de nouveaux critères pour le théorème de la limite central des processus stationnaires mélangeant. Enfin, nous terminons en démontrant qu'un processus stationnaire max-stable vérifiant la propriété de Markov est, quitte à renverser le temps, un processus max-autorégressif d’ordre 1The theme of this thesis is spatial extreme value theory and we focus on continuous max-stable processes. We begin with the convergence of the maximum of independent stochastic processes, by using the convergence of empirical measures to Poisson point processes. After that, we determine the regular conditional distributions of max infinitely divisible (max-i.d) processes. The representation of max-i.d. processes by Poisson point processes allows us to introduce the notions of extremal functions and hitting scenario. Our result relies on these new notions. Max-stable processes are max-i.d. processes, so we give an algorithm for conditional sampling and give an application to extreme precipitations around Zurich and extreme temperatures in Switzerland. We also find a upper bound for the β-mixing coefficient between the restrictions of a max-i.d. process on two disjoint closed subsets of a locally compact metric space. This entails a central limit theorem for stationary max-i.d processes. Finally, we prove that the class of stationary maxstable processes with the Markov property is equal, up to time reversal, to the class of stationary max-autoregressive processes of order 1
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Plée, Vincent. "Prédiction du comportement de phases et des enthalpies de mélange de gaz naturels atypiques contenant de l'argon, du monoxyde de carbone et de l'hélium." Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0186/document.
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Le développement du modèle prédictif E-PPR78, basé sur une méthode de contribution de groupe, a été entrepris depuis plus de dix ans pour prédire le comportement de systèmes multiconstituants. Ce modèle repose sur l'équation d'état de Peng-Robinson dans sa version de 1978 et les règles de mélanges de Van der Waals. Il utilise un seul paramètre d'interaction binaire, kij, qui dépend de la température. Afin de permettre au modèle E-PPR78 de prédire le comportement du gaz naturel, trois nouveaux groupes sont ajoutés : le monoxyde de carbone, l'hélium et l'argon. Pour cela, il a été nécessaire de former une base de données expérimentales la plus large possible contenant les mesures d'équilibres de phase et d'enthalpies de mélange pour les systèmes binaires constitués par ces trois groupes ainsi que ceux définis dans les études précédentes et présents dans le gaz naturel. Après une description de la classification des diagrammes de phase de Van Konynenburg et Scott, le modèle E-PPR78 est présenté. La troisième partie est consacrée à l'ajout des trois nouveaux groupes au sein du modèle. Les résultats sont obtenus avec une précision satisfaisante. Il apparaît clairement que le modèle E PPR78 est capable de prédire le comportement du gaz naturel dans des conditions de températures et de pressions particulièrement largesThe development of the predictive E-PPR78 model, based on a contribution group method, has been undertaken since ten years to predict accurately the behaviour of multi-component systems. This model lies on the Peng-Robinson equation of state with classical Van der Waals mixing rules. It uses a unique binary interaction parameter, kij, which is temperature dependant. To enable the E-PPR78 model to predict the behavior of natural gases, three new groups are added: carbon monoxide, helium and argon. It was necessary to build an experimental database, as exhaustive as possible, containing phase equilibrium and enthalpies of mixing data for binary systems formed by these groups and those defined in previous studies and present in natural gases. After a description of the classification scheme of Van Konynenburg and Scott, the E-PPR78 model is described. The third part is about the addition of the three new groups to the model. It clearly appears that the E-PPR78 model is able to predict the fluid-phase behavior of natural gases over wide ranges of temperatures and pressures
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Thurlow, Meghan Elizabeth. "Free Radicals and Reactive Intermediates in the Boundary Layer: Development and Deployment of Solid-State Laser Based Instrumentation to Measure Part per Trillion Mixing Ratios of Iodine Monoxide and Glyoxal In Situ." Thesis, Harvard University, 2012. http://dissertations.umi.com/gsas.harvard:10668.
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Advances in spectroscopic measurement techniques enabling highly accurate measurements of trace gases in the atmosphere are critical for furthering our understanding of the chemical processes that impact both climate and human health. This dissertation presents the development and deployment of laser-based instruments for measuring parts per trillion (pptv) concentrations of iodine monoxide and glyoxal. Iodine, which is primarily released from oceanic sources, is highly reactive in the atmosphere. Despite its trace concentrations, iodine plays a potentially important role in ozone destruction, the catalysis of mercury deposition, and the formation of marine clouds. An in situ instrument to detect iodine monoxide (IO) using laser-induced fluorescence was developed and then validated during a deployment to the Shoals Marine Laboratory (Appledore Island, ME) in August and September 2011. Mixing ratios up to 10 pptv of IO were observed with a strong tidal dependence. The instrumental detection limit \((3\sigma)\) of 0.36 pptv in 1 minute is indicative of unprecedented sensitivity. Glyoxal, the smallest alpha-dicarbonyl, serves as an atmospheric tracer of both the oxidation of biogenic volatile organic compounds in forest environments as well as secondary organic aerosol. Modeling studies indicate that production of glyoxal on a global scale is driven primarily by biogenic emissions, specifically emissions of isoprene. However, measurements of glyoxal in environments where isoprene dominates its production are limited. An instrument to detect glyoxal in situ by laser-induced phosphorescence was developed. The 3σ limit of detection of this instrument was 3.9 pptv in 1 minute. During July and August 2009, gas-phase measurements of glyoxal were made during the Community Atmosphere-Biosphere Interactions Experiment at the PROPHET tower in an isoprene-dominated forest site in northern Michigan. Additional measurements made throughout the campaign have been used to constrain a box model using the Master Chemical Mechanism. The model over-predicts glyoxal relative to the observed mixing ratios. Theoretically predicted reaction pathways implemented in many isoprene oxidation schemes exacerbate this disagreement.Chemistry and Chemical Biology
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Pérez, Herrero Pedro. "La pervivencia de las estructuras de poder del pasado y los retos para el perfeccionamiento del Estado de derecho en América Latina a comienzos del siglo XXI." Economía, 2012. http://repositorio.pucp.edu.pe/index/handle/123456789/118229.
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The essay explains why and how Latin American societies, during the period of1930 to 1980, accepted the different variants of populist regimes; why these political systems perpetuated for such a long time; what mechanisms were employed to manage internal order; why and how the destruction occurred in the decade of the 1980s; why at the beginning of the 21st century certain forms of populist-demagogicappeals in the Latin-American political panorama returned to the scene; why the State in Latin America reached such low levels of institutionalism halfway through the 20th century; why the discourse of mixed races transformed itself into the central element, capable of uniting the complex magma formed by structural heterogeneity; and why «old nationalisms» are giving way to new methods and alternative discourses about the concept of identity at the beginning of the 21st century.El ensayo explica por qué y cómo las sociedades latinoamericanas aceptaron, entre 1930–1980, las diferentes variantes de los regímenes populistas; por qué estos sistemas políticos se perpetuaron durante tanto tiempo; qué mecanismos se emplearon para gestionar el orden interno; por qué y cómo llegaron a su derrumbamiento en la década de 1980; por qué a comienzos del siglo XXI han vuelto a hacerse presentes ciertas formas populistas-demagógicas en el panorama político latinoamericano; por qué el Estado en América Latina alcanzó cotas tan bajas de institucionalidad a mediados del siglo XX; por qué el discurso del mestizaje se convirtió en un elemento central capaz de aglutinar el complejo magma generado por la eterogeneidad estructural; y por qué los viejos nacionalismos están dando paso a comienzos del siglo XXI a nuevas formas y discursos alternativos de la identidad.
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Ricky, Ricky. "Uppskalning av en svampkaka : process från avfallsbröd med en ätlig svamp." Thesis, Högskolan i Borås, Akademin för textil, teknik och ekonomi, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-23882.
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Stale bread contributes to the biggest volume of food waste in Sweden. Current method on recovering bread waste is by producing biogas or bioethanol. Despite advantages in the energy sector, the bread which still has relatively high quality could be recovered into new products with higher value, such as food for human consumption. Development of a product, termed ‘fungal cake’ by solid state fermentation on bread waste using Neurospora intermedia in small scale petri dishes have previously been successfully conducted. This study aims to scale up the production of fungal cake into bench scale production. Two systems using different bioreactors were used in this study. The first system operated in batch mode using a tray bioreactor, in which the effect of particle size, mixing, and bread loading were evaluated. The fermentation was conducted during 5 days. Bread crumb with a larger particle size of 2 mm resulted in similar outcomes as bread crumb with a smaller particle size of 0.5 mm in terms of CO2 evolution rate, cumulative CO2 production, starch, and protein content of the final product. However, larger particle size resulted in a more homogeneous growth of the fungus throughout the product, which is preferred. The presence of daily mixing had no significant effect compared to static condition for all measured variables. Thus, mixing could be introduced to promote product homogeneity. Likewise, bread loading had no significant effect on the measured variables, which implies that a higher productivity can be achieved using a higher bread loading. The second system operated in continuous mode using a newly developed continuous tubular bioreactor with product recycle. Two experiments, in which the residence time (48h and 24h) and recycle ratio (10/65 and 20/55) were conducted. Both experiments yielded product with stable starch and protein content, indicated by a stable CO2 evolution rate over time. The performance using continuous tubular bioreactor was compared to batch fermentation in tray bioreactor using the same ratio of inoculum and both system yielded product with the same starch and protein content. Successful operation in continuous bioreactor certainly improved the productivity of fungal cake production.
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Arce-Castillo, Pedro Felipe. "Modelagem do equilibrio de fases em misturas de dioxido de carbono supercritico e compostos presentes em produtos naturais." [s.n.], 2002. http://repositorio.unicamp.br/jspui/handle/REPOSIP/267410.
Full textAbstract:
Orientador : Martin AznarDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
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Resumo: A modelagem e simulação de processos de extração supercrítica requer uma boa predição das condições do equilíbrio entre fases, condições que determinam a maior concentração do líquido ou sólido (soluto) a ser extraído pelo fluido supercrítico (solvente). O problema principal na modelagem dos sistemas que se encontram em processos de extração supercrítica é a grande diferença de tamanho (peso molecular) entre as substâncias envolvidas (soluto e fluido supercrítico) e a baixa concentração do soluto no fluido supercrítico. Atualmente, as regras de mistura em uso não consideram de forma adequada o problema da grande assimetria; portanto, não permitem uma boa predição do equilíbrio entre fases. É proposta uma regra de mistura (Regra Não Quadrática Generalizada) baseada nas regras de mistura clássicas de van der Waals, com modificações nos parâmetros de interação, tanto na constante de energia quanto na de volume. Um parâmetro de interação binário, dependente da concentração, é usado para estimar a constante de energia; outro parâmetro de interação binário, independente da concentração e com um efeito diferenciado sobre o componente mais pesado quando comparado ao fluido supercrítico, é usado para estimar a constante de volume. Este novo arranjo considera como casos particulares os modelos conhecidos de Panagiotopoulos-Reid e Adachi-Sugie, entre outros. A forma não quadrática generalizada proposta tem todas as boas características desses modelos, permitindo maior flexibilidade na correlação dos dados experimentais. Usou-se outra regra de mistura, Regra de Kurihara-Tochigi-Kojima, a qual está baseada na parte residual da energia livre excedente à pressão infinita, atuando diretamente sobre a constante de energia da equação de estado. Os resultados obtidos com as duas regras de misturas citadas anteriormente são comparados com os resultados obtidos da regra modificada de W ong-Sandler e da regra convencional de van der Waals. As regras de mistura descritas anteriormente, junto com as equações cúbicas de estado de Soave-Redlich-Kwong, Peng-Robinson e a equação cúbica de estado generalizada de Patel-Teja-Valderrama, são usadas para descrever o equilíbrio líquidovapor e sólido-vapor em misturas assimétricas binárias (CO2 supercritico + um componente pesado ou produto natural). Neste trabalho foram estimados os parâmetros de interação binários tanto para a modelagem do equilíbrio líquido-vapor dos sistemas binários: CO2 +limoneno, linaloo_ ac. láurico, ac. palmítico, ac. oléico, ac. linoleico, 2-metil-pentanol, 1octanol, l-decanol e a.-pineno, quanto para a modelagem do equilíbrio sólido-vapor dos sistemas binários: CO2 + naftaleno, 2,3-dimetilnaftaleno, 2,6-dimetilnaftaleno, fenantreno,antraceno, p-colesterol, cafeína, p-caroteno e capsaicina. A predição dos parâmetros de interação binários realiza-se usando um método modificado de Marquardt com uma função objetivo que contém a pressão de saturação e a concentração na fase gás para o equilíbrio líquido-vapor e apenas a concentração na fase gás para o equilíbrio sólido-vapor. As sub-rotinas computacionais foram escritas considerando a possibilidade de múltiplas soluções e conseqüentemente, a busca dos parâmetros ótimos realiza-se sob um amplio intervalo de soluções possíveis. Os resultados (desvios na pressão e na fração molar na fase vapor para o ELV e apenas os desvios na fração molar na fase vapor para o ESV) indicam que as regras de mistura NQG e WS modificada permitem predizer melhor o comportamento dos sistemas binários estudados. A influencia das EDEs para uma mesma regra de mistura não é apreciável
Abstract: Modeling and simulation of supercritical extraction processes request a good prediction of conditions of phase equilibrium, conditions that determine the higher concentration of liquid or solid (solute) to be extracted by supercritical fluid (solvent). The main problem in modeling of systems found in supercritica1 extraction processes is the great size difference (molecular weights) between involved substances (solute and supercritical fluid) and low concentration of solute in supercritical fluid. Now, mixing roles in use don't consider of appropriate way the problem of great asymmetry, therefore don't alIow a good prediction of phase equilibrium. A mixing role is proposed (Generalized Non Quadratic Rule), which is based on c1assic mixing rules of van der Waals, with modifications in the interaction parameters, as much in energy constant as in volume constant. A binary interaction parameter, dependent of concentration, is used to estimate energy constant; another binary interaction parameter, independent of concentration and with a differentiated effect on heavier component when compared with supercritical fluid, is used to estimate volume constant. This new arrangement considers as private cases well-known models of Panagiotopoulos-Reid and Adachi-Sugie among others. This generalized non quadratic form has all good characteristics of those models, allowing larger flexibility in correlating experimental data. Other mixing rule was used, Kurihara-Tochigi-Kojima Rule (based on the residual part of the excess free energy to infinite pressure), acting direct1y on energy constant of the state equation. Results obtained with the two mixing roles previously mentioned are compared with obtained results of modified role of Wong-Sandler and conventional role of van der Waals. The mixing roles described previously, joined with the Soave-Redlieh-Kwong and Peng-Robinson's cubic equations of state and the Patel-Teja-Valderrama generalized cubic equation of state, are used to describe liquid-vapor and solid-vapor equilibrium in asymmetrie binary mixtures (supercritical CO2 + heavy component or natural product). In this work were estimated the binary interaction parameters as much for the modeling of liquid-vapor equilibrium of binary systems: COz + limonene, linalool, lauric acid, palmitic acid, oleic acid, linoleic acid, 2-methyl-pentanol, l-octanol, l-decanol and a-pinene, as for modeling of solid-vapor equilibrium of the binary systems: CO2 + naphtalene, 2,3dimethylnaphtalene, 2,6-dimethylnaphtalene, phenanthrene, anthracene, B-eholesterol, caffeine, B-carotene and capsaicin. A Marquardt modified method with a objective function (saturation pressure and vapor phase concentration for liquid-vapor equilibrium and on1y vapor phase concentration for solid-vapor equilibrium) was used to predict binary interaction parameters. The computational subroutines were written considering the possibility of multiple solutions and consequently, the search of the optimum parameters was done on a large interval of possible solutions. Results (deviations in pressure and molar fraction in vapor phase for ELV and on1y deviations in fraction molar in phase vapor for ESV) indicate that mixture roles: NQG and modified WS allow to predict better the behavior of studied binary systems. The influence of EDEs for a same mixture role is not appreciable
Mestrado
Desenvolvimento de Processos Químicos
Mestre em Engenharia Química
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Ibrahim, Mohamed Asim Y. "Co-processing of drugs and co-crystal formers and its effect on pharmaceutical dosage-form performance. Co-crystallization of urea/ 2-methoxybenzamide, caffeine/ malonic acid, caffeine/ oxalic acid and theophylline/ malonic acid systems: Solid-state characterization including imaging, thermal, X-ray and Raman spectroscopic techniques with subsequent evaluation of tableting behaviour." Thesis, University of Bradford, 2008. http://hdl.handle.net/10454/12760.
Full textAbstract:
This dissertation has focused on the solid-state characterization of different co-crystal system as well as the effect of co-crystallization of these systems on pharmaceutical dosage form performance. Urea/ 2-MB, caffeine/ malonic acid, caffeine/ oxalic acid and theophylline/ malonic acid co-crystals were prepared using co-grinding- and co-precipitation techniques. In addition, the synthesis of co-crystals through two novel methods has been demonstrated. This includes compaction and convection mixing. The solid-state characterization of the co-crystals has been carried out using XRPD, Raman spectroscopy, DSC, TGA, hot-stage microscopy and SEM. After preparation of co-crystals, tablets have been produced from co-ground-, co-precipitated-, and physical mixtures using Compaction Studies Press (Kaleva), and the data were recorded to compare between the different mixtures, regarding compactibilty, compressibility and deformational properties. The DSC results showed that the physical mixtures of all systems, formed co-crystals during heating process. For systems of urea/ 2-MB, caffeine/ malonic acid and theophylline/ malonic acid, the co-ground mixture produced tablets with higher tensile strength compared with either co-precipitated or physical mixture. However, for caffeine/ oxalic acid system, the tensile strengths of compacts produced from the physical mixture were greater than those obtained from either co-ground or co-precipitated mixtures. The Heckel data suggested that urea/ 2-MB, caffeine/ malonic acid and theophylline/ malonic acid systems are Type 1 materials, as an extensive linearity during compression was indicative of a plastic deformation mechanism, while the caffeine/ oxalic acid system was Type 2 materials. However, the co-precipitated mixture of urea/ 2-MB system was the least compressible, as it possessed the greatest value of yield pressure (85 MPa) and the highest elastic recovery (7.42%). The co-precipitated mixture of both of caffeine/ malonic acid and theophylline/ malonic acid systems was the most compressible with small yield pressure values of (44 & 80 MPa) and elastic recovery of (7.2% & 6.56%), respectively. The co-ground mixture of caffeine/ oxalic acid possessed the highest value of yield pressure (166 MPa) and thus the lowest compressibility among other mixtures. Furthermore, the addition of microcrystalline cellulose and α-lactose monohydrate has affected the crystallinity as well as the tableting properties of the co-crystals. After the addition of excipients, the tensile strength of compacts was about 2 times higher than any other mixture. Finally, urea/ 2-MB and caffeine/ malonic acid co-crystals were successfully synthesized through convection mixing and compaction.Islamic University of Omdurman and the Ministry of Higher Education in Sudan
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Figura, Florent. "Rhéologie d’un nouveau matériau granulaire carboné." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSEI009.
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Carbone Savoie est une société française spécialisée dans les solutions cathodiques en carbone et graphite pour l’électrolyse de l’aluminium primaire. La fabrication de ces produits requiert un savoir-faire important en raison de la complexité de procédé. Le malaxage, première étape du procédé, permet le mélange intime des particules carbonées et d’un liant. Les grains carbonés de tailles variées comme le coke calciné, anthracite calciné, et le graphite constituent un empilement multimodal d’une dizaine de microns à quelques centimètres. Le liant actuel est liquide à haute température, se caractérise par un haut rendement en carbone, est cokéfiable mais toxique. La législation européenne sur les produits chimiques (REACH) l’a identifié comme « substance extrêmement préoccupante », le risque associé étant une interdiction de son utilisation. Dans ce contexte, Carbone Savoie a lancé un projet de recherche visant à substituer cette matière première dangereuse. Le premier objectif a été de déterminer des compositions possibles pour ce nouveau liant ainsi que leur comportement rhéologique. Une première composition a montré un comportement newtonien à pH basique. Un additif à point de gélification, dont le comportement a fait l’objet d’une étude, a été utilisé pour une deuxième composition. La meilleure méthode de mélange fut ensuite sélectionnée puis son efficacité avec le nouveau liant validée. Une troisième composition, qui est une suspension, a montré un comportement rhéofluidifiant. Cette dernière s’est avérée être la meilleure candidate pour substituer le brai. Le deuxième objectif du travail a été la détermination des conditions de malaxage avec le nouveau liant. L’étude du mélange granulaire carboné est basée sur une méthode de suivi d’intensité de malaxage. Grâce à la courbe d’intensité enregistrée en fonction du ratio massique liquide/solide, les différents états de l’eau dans le mélange en fonction de la saturation en liant du système ont été définis : régime pendulaire, funiculaire, capillaire et goutte. Le régime capillaire est particulièrement intéressant car il s’agit du régime d’extrusion des cathodes. L’influence sur le procédé (cinétique de mouillage, étendue du régime capillaire) de la viscosité du liant a été étudiée : une viscosité élevée permet une plus grande tolérance du procédé vis-à-vis des variations de l’empilement granulaire des matières sèches d’une formulation à l’autre ou encore la difficulté de produire des poudres de granulométrie fixe. Enfin, une corrélation entre les résultats obtenus et l’échelle industrielle a été trouvée. Les propriétés finales d’une cathode peuvent être reliées à la qualité de la pâte en sortie de malaxeur grâce à la détermination de la cohésion via une cellule de cisaillement annulaireCarbone Savoie is a French company specialized in the production of carbon and graphite cathodic solutions for the primary aluminum industry. The production of cathodes requires an important know-how because of its complex manufacturing process. The first step of the process consists in mixing the carbonaceous raw materials with a binder. The raw materials (calcined coke and anthracite or graphite) have different size and represent a multimodal carbon aggregate (from tens of microns to a few centimeters). The current binder is liquid at high temperature, has a high carbon yield and is coking but poisonous. The European regulations on chemical products (REACH) identified the pitch binder as “substance of very high concern”. Therefore, that product could become prohibited. Within this context, Carbone Savoie initiated a research project in order to substitute that hazardous material. First of all, the project aims at determining possible compositions for the new binder and to describe their rheological behavior. A first formulation had a Newtonian behavior for high pH values. An additive with a gel point which behavior has been studied was used for a second formulation. The best mixing process was then chosen and its efficiency was tested with this new binder. A third formulation which was a suspension showed a shear-thinning behavior. It appeared to be the best candidate to substitute pitch as a binder for the production of cathode blocks. The second goal of the project was the determination of the mixing conditions with this new binder. The study of the mixing of the carbon aggregate with the binder is based on a tracking of the mixing intensity. Thanks to the plot of the intensity-liquid/solid ratio curve, different states were defined for the system according to the binder content (pendular state, funicular state, capillary state and solid/liquid dispersion state). The capillary state is of a major concern because the paste is extruded in that state. The impact on the process (wetting kinetics, width of the capillary state) of the rheological behavior of the binder has been studied: a high viscosity allows a better tolerance to the variability in the size of the carbon aggregate from a formulation to another and also to the trouble of producing powders with very small particles sizes. Finally, a correlation between these results and the industrial scale has been found. Final properties of cathodes blocks can be linked with the paste quality just after the mixing step thanks to the determination of the paste cohesion with a ring shear tester
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Ibrahim, Mohamed Asim Yousif. "Co-processing of drugs and co-crystal formers and its effect on pharmaceutical dosage-form performance : co-crystallization of urea/2-methoxybenzamide, caffeine/malonic acid, caffeine/oxalic acid and theophylline/malonic acid systems : solid-state characterization including imaging, thermal, X-ray and Raman spectroscopic techniques with subsequent evaluation of tableting behaviour." Thesis, University of Bradford, 2008. http://hdl.handle.net/10454/12760.
Full textAbstract:
This dissertation has focused on the solid-state characterization of different co-crystal system as well as the effect of co-crystallization of these systems on pharmaceutical dosage form performance. Urea/ 2-MB, caffeine/ malonic acid, caffeine/ oxalic acid and theophylline/ malonic acid co-crystals were prepared using co-grinding- and co-precipitation techniques. In addition, the synthesis of co-crystals through two novel methods has been demonstrated. This includes compaction and convection mixing. The solid-state characterization of the co-crystals has been carried out using XRPD, Raman spectroscopy, DSC, TGA, hot-stage microscopy and SEM. After preparation of co-crystals, tablets have been produced from co-ground-, co-precipitated-, and physical mixtures using Compaction Studies Press (Kaleva), and the data were recorded to compare between the different mixtures, regarding compactibilty, compressibility and deformational properties. The DSC results showed that the physical mixtures of all systems, formed co-crystals during heating process. For systems of urea/ 2-MB, caffeine/ malonic acid and theophylline/ malonic acid, the co-ground mixture produced tablets with higher tensile strength compared with either co-precipitated or physical mixture. However, for caffeine/ oxalic acid system, the tensile strengths of compacts produced from the physical mixture were greater than those obtained from either co-ground or co-precipitated mixtures. The Heckel data suggested that urea/ 2-MB, caffeine/ malonic acid and theophylline/ malonic acid systems are Type 1 materials, as an extensive linearity during compression was indicative of a plastic deformation mechanism, while the caffeine/ oxalic acid system was Type 2 materials. However, the co-precipitated mixture of urea/ 2-MB system was the least compressible, as it possessed the greatest value of yield pressure (85 MPa) and the highest elastic recovery (7.42%). The co-precipitated mixture of both of caffeine/ malonic acid and theophylline/ malonic acid systems was the most compressible with small yield pressure values of (44 & 80 MPa) and elastic recovery of (7.2% & 6.56%), respectively. The co-ground mixture of caffeine/ oxalic acid possessed the highest value of yield pressure (166 MPa) and thus the lowest compressibility among other mixtures. Furthermore, the addition of microcrystalline cellulose and α-lactose monohydrate has affected the crystallinity as well as the tableting properties of the co-crystals. After the addition of excipients, the tensile strength of compacts was about 2 times higher than any other mixture. Finally, urea/ 2-MB and caffeine/ malonic acid co-crystals were successfully synthesized through convection mixing and compaction.
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Guilbaud, Sarah. "Etude du vieillissement des aérosols inorganiques industriels en milieu urbain." Thesis, Littoral, 2018. http://www.theses.fr/2018DUNK0524/document.
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Lors de leur séjour dans l’atmosphère, les aérosols sont soumis, entre autres, à des processus d’agrégation, ainsi que de condensation sur leurs surfaces. Ces processus, dit de vieillissement, dépendent du temps de résidence des particules dans l’atmosphère, des conditions météorologiques et de l’environnement chimique rencontré. Cette étude vise à caractériser l’aérosol inorganique et étudier son évolution physico-chimique sur quelques dizaines de milliers de mètres, dans les panaches industriels et urbains où les concentrations atmosphériques en particules fines (PM₁₀) sont relativement élevées. Il s’agit notamment de rendre compte de l’évolution des particules d’aérosol primaire lors d’épisodes de formation d’aérosols secondaires inorganiques.Dans ce cadre, dans un premier temps, une nouvelle méthodologie d’analyse des aérosols inorganiques, à basse température, par cryo-microscopie électronique (cryo-TSEM-EDX) a été mise au point. L’enjeu était notamment de rendre compte de l’état de mélange des composés atmosphériques d’origine secondaire (composés semi-volatils), avec l’aérosol primaire. Ces développements analytiques ont tout d’abord été réalisés à l’aide de composés modèles, avant d’être validés sur particules environnementales. Dans un second temps, l’étude des processus physico-chimiques mis en jeu lors du vieillissement des aérosols, à l’échelle locale (quelques kilomètres), a été réalisée au cours d’une campagne intensive de terrain sur le dunkerquois, visant à étudier plus particulièrement l’évolution des émissions industrielles en milieu urbain. Des prélèvements ont ainsi été réalisés en bordure de zone industrielle et sur de sites "récepteurs" sous l’influence potentielle des émissions industrielles. Les analyses réalisées sur ces particules par cryo-SEM-EDX ont notamment montré qu’en zone péri-urbaine, à quelques kilomètres de la zone industrielle, des particules émises par la sidérurgie, comme les oxydes de fer, évoluaient rapidement, pour se retrouver, en mélange interne, associés à de la matière organique particulaire. En parallèle, nous avons pu caractériser, sur ces sites récepteurs, la présence d’aérosols inorganiques secondaires absents de la zone source et donc formés au sein de l’air ambiant, lors du survol de l’agglomération dunkerquoiseDuring their transport in the atmosphere, aerosols are subject, for example, to aggregation and condensation processes on their surfaces. These processes, so-called aging, depend on particle residence time in the atmosphere, meteorological conditions and chemical environment. This study aims to characterize inorganic aerosols and to highlight their physico-chemical evolution on a few tens of thousands meters, from an industrial area to the urban environment of Dunkirk (Northern France), in which PM₁₀ concentrations are quite important. It notably includes reporting on the evolution of primary particles during the formation of secondary inorganic aerosols. First, a new analytical methodology of inorganic aerosols, at low temperature, with cryo-electronic microscopy (cryo-TSEM-EDX) has been developed. Our goal was to characterize the mixing state of secondary atmospheric components (semi-volatile components) with primary aerosols. These analytical developments have been realized with model particles, before validation on real atmospheric particles. In a second time, the study of physico-chemical processes involved in the aging of industrial inorganic aerosols has been undertaken through an intensive field campaign. The objective is to describe the particles evolution between the industrial zone and receptor sites located in the suburb of Dunkirk. Our main results show that Fe-rich particles (Fe oxides), released in the atmosphere by steelworks, incorporate particulate organic matter in a few kilometers, between the source and receptor sites. In addition, the formation of secondary inorganic aerosols (SIA), not present at the source, has been evidenced. Clearly, these SIA have been formed during the transport of air masses over the urban area
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Álvarez, Álvarez Víctor Hugo. "Modelagem do equilíbrio liquido-vapor em misturas contendo liquidos ionicos." [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/266141.
Full textAbstract:
Orientador: Martin AznarDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
Made available in DSpace on 2018-08-08T09:32:38Z (GMT). No. of bitstreams: 1 AlvarezAlvarez_VictorHugo_M.pdf: 1355509 bytes, checksum: c9710252adab51dca90a695fc91a5aa6 (MD5) Previous issue date: 2007
Resumo: Os líquidos iônicos têm recebido considerável interesse devido a seu potencial como solventes projetados, que podem ser adaptados a vários tipos de processos industriais. A razão principal do interesse nos líquidos iônicos como solventes é sua baixa pressão de vapor, a qual minimiza os riscos de exposição e contaminação ambiental. Esta pesquisa visa realizar um estudo completo e sistemático sobre duas regras de mistura utilizando a equação de estado cúbica de Peng-Robinson para correlacionar o equilíbrio líquido-vapor em sistemas contendo líquidos iônicos. O problema principal nesta modelagem é a predição da baixa concentração do líquido iônico na fase vapor.Até o momento são escassas as publicações das propriedades críticas dos líquidos iônicos, motivo pelo qual escolheu-se uma equação com baixa quantidade de parâmetros, como a equação de estado cúbica de Peng-Robinson. Estudou-se o parâmetro dependente da temperatura a(T) e a regra de mistura de van der Waals. Os parâmetros a(T) comparados foram os propostos por Soave (1972) e por Almeida et al. (1991). Nos primeiros testes da modelagem foi utilizada a regra de mistura de van der Waals, mas para melhores resultados utilizou-se a regra de mistura de Wong-Sandler com os modelos UNIQUAC ou NRTL. Desenvolveu-se uma estratégia de modelagem molecular para calcular os parâmetros estruturais de área e volume do modelo UNIQUAC para os líquidos iônicos. Os parâmetros de interação foram calculados independentes da temperatura e concentração. Foram estudadas misturas binárias para descrever o equilíbrio líquido-vapor em altas pressões (CO2 ou CHF3 supercrítico + líquido iônico) e a baixas pressões (hidrocarbonetos + líquidos iônicos). Logo, os parâmetros de interação binária foram utilizados na correlação de sistemas ternários a baixa pressão com a regra de mistura de Wong-Sandler. A estimação dos parâmetros de interação binários foi realizada em um primeiro momento com o método de Levenberg-Marquardt e depois, com melhor sucesso, utilizou-se um algoritmo genético. A função objetivo utilizada contém a pressão do sistema e a composição do líquido iônico na fase gás. Os resultados para a modelagem com a regra de mistura de van der Waals apresentam altos desvios na pressão, mas com a regra de mistura de Wong-Sandler têm-se baixos desvios na pressão e uma baixa concentração do líquido iônico na fase gás até 100 atm. Os resultados mostram uma boa correlação dos sistemas ternários. Foi usado um teste de consistência termodinâmica para o sistema CO2 + hexafluorofosfato de 1-butil-3-metilimidazolio, para o qual há quatro conjuntos de dados conflitantes na literatura. Os resultados mostraram que, um conjunto de dados é termodinamicamente consistente, outro é não inteiramente consistente e os outros dois são termodinamicamente não consistentes
Abstract: The ionic liquids have received considerable interest due to his potential as designer solvents, that can be adapted in several types of industrial processes. The main reason of the interest in the ionic liquid as solvent is his negligible vapor pressure, which decreases the risks of exposition and environmental contamination. This research tries realize a complete and systematic study of two mixing rule in the Peng-Robinson equations of state for correlate and predict the equilibrium liquid-vapor in systems containing ionic liquids. The main problem in modeling the liquid-vapor equilibrium is the prediction of the negligible concentrations of ionic liquid in the phase vapor. Up to the moment the publications of the critical properties of the ionic liquids are scarce, reason for which chose an equation with low amount of parameters, as the cubic equation of state of Peng-Robinson. In this work, was studied the a(T): parameter dependent of the temperature and the mixing rule of van der Waals. The compared a(T): parameters were proposed for Soave 1972) and Almeida et al. (1991). In the first moment of the modeling was used the van der Waals mixing rule, after for good results was used the Wong-Sandler mixing rule with the UNIQUAC or NRTL model. A molecular modeling strategy was used to calculate the volume and surface area parameters of ionic liquids for UNIQUAC. Independent temperature and concentration interaction parameters were calculated. The binary mixtures were studied to describe the liquid-vapor equilibrium included high pressures (CO2 or CHF3 supercritical + ionic liquid) and low pressures (hydrocarbons + ionic liquid). After, the binary interaction parameters were used for correlated the ternary system at low pressure with the Wong-Sandler mixing rule. For evaluating the binary interaction parameters was used in first moment the Levenberg-Marquardt method and after, with best results was used a genetic algorithm. The objective function uses the pressure of the systems and the ionic liquid fraction mol in the gas phase. The results for correlation with van der Waals mixing rule show high deviations in the pressure system, but the Wong-Sandler mixing rule had low deviations in the pressure system and low concentration of the ionic liquid in the gas phase, up to 100 atm. The ternary system can be correlate with acceptable accuracy. A test of thermodynamic consistency was used for a binary system CO2 + 1-n-butyl-3-methylimidazolium hexafluorophosphate, it has four conflicts data set in the literature. The results show one data set thermodynamically consistent, one data set not fully consistent and two data set thermodynamically inconsistent
Mestrado
Desenvolvimento de Processos Químicos
Mestre em Engenharia Química
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Le, Guennec Yohann. "Développement d’équations d’état cubiques adaptées à la représentation de mélanges contenant des molécules polaires (eau, alcools, amines …) et des hydrocarbures." Thesis, Université de Lorraine, 2018. http://www.theses.fr/2018LORR0245/document.
Full textAbstract:
L’objectif principal de ce travail de thèse est de développer un modèle thermodynamique de type équation d’état cubique, permettant de prédire avec un maximum de précision les propriétés thermodynamiques des corps purs (des comportements de phases aux propriétés énergétiques - enthalpie, capacité calorifique - en incluant les propriétés volumiques) et des mélanges (équilibres de phases dans les régions sub- et supercritiques, points critiques, propriétés énergétiques, densités …), y compris les plus complexes. Concernant les corps purs tout d’abord : en nous appuyant sur la connaissance acquise par les études publiées pendant près d’un siècle et demi sur les équations d’état cubiques, nous avons identifié deux leviers pour accroître la précision de ces modèles. Le premier concerne la sélection d’une fonction α optimale (cette fonction est une quantité clef apparaissant dans le terme attractif du modèle) dont le bon paramétrage permet de représenter précisément les propriétés à saturation des corps purs, telles que la pression de saturation, l’enthalpie de vaporisation et la capacité calorifique du liquide à saturation. Afin que la fonction α puisse être extrapolée au domaine des hautes températures, nous avons défini les contraintes mathématiques que celle-ci doit respecter. Le second levier est le paramètre de translation volumique, paramètre clef pour la bonne représentation des densités liquides. Ces réflexions et les études associées sont à la base du développement des modèles tc-RK et tc-PR, utilisant une fonction α extrapolable à haute température ainsi qu’un paramètre de translation volumique, garantissant une précision jusqu’alors inégalée des propriétés sub- et supercritiques des corps purs prédites par des équations d’état cubiques. Afin d’étendre les modèles tc-RK et tc-PR aux mélanges, il a été nécessaire de développer des règles de mélange appropriées pour deux paramètres de l’équation d’état des mélanges : le covolume et le paramètre attractif. Des règles de mélanges récemment proposées qui combinent équation d’état et modèle de coefficient d’activité ont été adoptées. Les valeurs optimales des paramètres universels de ces règles de mélange ont été identifiées dans le cadre de cette thèse. Une règle de mélange linéaire pour le paramètre de translation volumique du mélange a été sélectionnée ; il a été prouvé que cette règle de mélange garantit l’invariance des propriétés d’équilibre de phases et des propriétés énergétiques entre les modèles translatés et non translatés. Afin de définir le modèle de coefficient d’activité optimal à intégrer dans la nouvelle règle de mélange, une base de données de 200 systèmes binaires a été développée. Ces systèmes binaires ont été sélectionnés afin d’être représentatifs des différents types d’interactions qui peuvent exister dans les mélanges non électrolytiques. La base de données accorde une place significative aux systèmes dits associés, qui sont certainement parmi les plus difficiles à modéliser par une équation d’état. In fine, cette thèse pose toutes les bases du développement d’une équation d’état cubique des mélanges. Le choix du modèle de coefficient d’activité optimal, la détermination des paramètres d’interactions binaires des 200 systèmes de la base de données et leur prédiction constituent des suites possibles de ce travailThe main objective of this thesis work is to develop a cubic equation of state thermodynamic model able to accurately predict the thermodynamic properties of pure compounds (from phase equilibrium data to energetic properties – enthalpy, heat capacity – and volume properties) and mixtures (phase equilibria in sub- and supercritical regions, critical points, energetic properties, densities…), including the most complex ones. Starting with pure compounds: relying on the knowledge collected all through the years from Van der Waals seminal work about cubic equations of state, we identified two levers to increase cubic-model accuracy. First is the selection of the optimal α function (this function is a key quantity involved in the model attractive term) the proper parameterization of which entails an accurate representation of pure-compound saturation properties such as saturation pressure, enthalpy of vaporization, saturated-liquid heat capacity. In order to safely extrapolate an α functions to the high temperature domain, we defined the mathematical constraints that it should satisfy. The second lever is the volume translation parameter, a key parameter for an accurate description of liquid densities. These studies led to the development of the tc-PR and tc-RK models, using an α function that correctly extrapolates to the high temperature domain so as a volume translation parameter, ensuring the most accurate estimations of pure-compound sub- and supercritical property from a cubic equation of state. In order to extend the tc-PR and tc-RK models to mixtures, it was necessary to develop adequate mixing rules for both equation of state parameters: the covolume and the attractive parameter. Recently proposed mixing rules combining an equation of state and an activity coefficient model have been retained. Optimal values of the mixing rules universal parameters have been identified in the framework of this thesis. A linear mixing rule for the volume translation parameter has been selected; it has been proven that this mixing rule does not change the phase equilibrium and energetic properties when switching from a translated to an untranslated model. In order to define the optimal activity coefficient model to include in the new mixing rule, a 200 binary-system database has been developed. These binary systems have been selected to be representative of the different kinds of interactions that can exist in non-electrolytic mixtures. The database includes in particular systems containing associating compounds, which are certainly among the most difficult ones to model with an equation of state. In fine, this thesis sets all the bases for the development of a cubic equation of state for mixtures. The selection of the optimal activity-coefficient model, the estimation of binary interaction parameters for the 200 binary systems from the database and their prediction are possible continuations of this work
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Paz, Sidrak Jos? da. "Infer?ncia do ponto de orvalho em amostras de g?s natural processado." Universidade Federal do Rio Grande do Norte, 2011. http://repositorio.ufrn.br:8080/jspui/handle/123456789/15819.
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This dissertation aims to assess the representativeness of the manual chilled mirror analyzer (model II Chanscope 13-1200-CN-2) used for the determination of condensed hydrocarbons of natural gas compared to the indirect methods, based on thermodynamic models equation of state. Additionally, it has been implemented in this study a model for calculating the dew point of natural gas. The proposed model is a modification of the equation of state of Peng-Robinson admits that the groups contribution as a strategy to calculate the binary interaction parameters kij (T) temperature dependence. Experimental data of the work of Brown et al. (2007) were used to compare the responses of the dew point of natural gas with thermodynamic models contained in the UniSim process simulator and the methodology implemented in this study. Then two natural gas compositions were studied, the first being a standard gas mixture gravimetrically synthesized and, second, a mixture of processed natural gas. These experimental data were also compared with the results presented by UniSim process simulator and the thermodynamic model implemented. However, data from the manual analysis results indicated significant differences in temperature, these differences were attributed to the formation of dew point of water, as we observed the appearance of moisture on the mirror surface cooling equipment
O presente trabalho de disserta??o tem por objetivo avaliar a representatividade do analisador manual de espelho refrigerado (Chanscope II modelo 13-1200-C-N-2) usado para a determina??o do condensado de hidrocarbonetos de g?s natural frente aos m?todos indiretos, fundamentados em modelos termodin?micos de equa??o de estado. Adicionalmente, tem sido implementado neste estudo um modelo para c?lculo do ponto de orvalho de g?s natural. O modelo proposto constitui uma modifica??o na equa??o de estado de Peng-Robinson que admite a contribui??o de grupos como estrat?gia para calcular os par?metros de intera??o bin?ria kij(T) com depend?ncia da temperatura. Dados experimentais do trabalho de Brown et al. (2007) foram utilizados para comparar as respostas de ponto de orvalho do g?s natural com os modelos termodin?micos contidos no simulador de processo UniSim e com a metodologia implementada neste estudo. Em seguida, duas composi??es de g?s natural foram estudadas, sendo a primeira uma mistura padr?o de g?s sintetizada gravimetricamente e, a segunda, uma mistura de g?s natural processado. Tais dados experimentais foram tamb?m comparados com os resultados apresentados pelo simulador de processo UniSim e pelo modelo termodin?mico implementado. No entanto, os dados do analisador manual indicaram diferen?as significativas nos resultados de temperaturas, sendo estas diferen?as atribu?das ? forma??o de ponto de orvalho de ?gua, j? que foi observado o aparecimento de umidade sobre a superf?cie do espelho refrigerado do equipamento
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Ngagine, Soulemane Halif. "Chemical heterogeneity of atmospheric particles in urbanized and industrialized environments during pollution events." Thesis, Littoral, 2022. http://www.theses.fr/2022DUNK0617.
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Ce travail de thèse vise à améliorer notre connaissance des sources proches et lointaines contrôlant le dépassement des seuils réglementaires de qualité de l’air, tels qu’ils peuvent être appréciés par les réseaux de mesure existants, sur le site fortement industrialisé et urbain du Grand Dunkerque. Il s’agit notamment de s’appuyer sur le calcul d’un indice d’état de mélange des particules, prenant en compte l’hétérogénéité de leur composition élémentaire, celle-ci étant liée à leur temps de séjour dans l’air et à la distance entre les sources et le site récepteur étudié. Pour répondre à cette problématique, il a fallu dans un premier temps développer un impacteur séquentiel de particules à haute résolution temporelle, nommé TRAPS, qui répondait au besoin de suivre les changements rapides observés au sein des particules atmosphériques lors d’épisodes de pollution. Couplé à un granulomètre et après analyse individuelle des particules prélevées par microscopie électronique (MEB-EDX), le TRAPS permet de rendre compte de l’évolution physico-chimique des particules atmosphériques au cours du temps. Dans la première partie de cette thèse, des expériences menées en laboratoire et une campagne de terrain ont permis de valider notre prototype, de rendre compte de la dynamique de dépôt des particules sur les zones d’impaction et de vérifier les diamètres de coupure des étages grossier et fin du TRAPS, déterminés respectivement à 1.32µm et 0.13µm. Une étude statistique des épisodes de pollution aux PM₁₀ survenus sur le grand dunkerquois a ensuite été réalisée sur 3 ans, entre 2018 et 2020. Elle nous a permis d’identifier 12 principaux types d’épisodes sur la base de leur étendue spatiale, mais aussi des conditions locales de dispersion des polluants. On a pu ainsi identifier des épisodes locaux et des épisodes régionaux observés, soit en conditions atmosphériques stationnaires ou au contraire en conditions de dispersion des pollutions à plus grande échelle. Alors que 78 % des jours de dépassement du seuil réglementaire des PM₁₀ correspondent à des épisodes locaux, les 22.4% restant correspondent à des panaches de pollution d’étendue au moins régionale, avec une proportion égale des jours de dépassements en condition de dispersion et en conditions stationnaires. Hormis les épisodes très localisés, une étude fine de la variabilité temporelle des concentrations en particules fines (PM₂.₅) montre la présence systématique d'une période d'accumulation progressive des polluants, pouvant atteindre une dizaine d'heures et caractérisée par une contribution importante de ces particules. La dernière partie de ce travail a consisté en l'étude de la composition et l'état de mélange des particules individuelles collectées lors d'évènements de pollution sur la zone du Grand Dunkerque en 2021. La campagne a permis l'échantillonnage et la caractérisation de 5 épisodes de pollution durant lesquels le TRAPS était déployé en parallèle d'autres instruments fournissant des informations complémentaires sur la granulométrie des aérosols, la météorologie ou la dynamique atmosphérique. Près de 28000 particules individuelles ont été caractérisées par MEB-EDX. Avec plus de 90% des échantillons associés à des valeurs de l'indice d'état de mélange chimique supérieures à 0.5, il est possible d'affirmer que les particules collectées sur la zone du Grand Dunkerque, durant ces épisodes de pollution, sont, en général, de composition très hétérogène à l'échelle de la particule individuelle (particules dites "en mélange interne"). Les résultats obtenus montrent en outre une influence de l'origine, locale ou transportée, des particules sur leur composition chimique et par là même sur l'indice d'état de mélange chimique de la population de particules échantillonnées. Une évolution croissante de l'indice d'état de mélange avec le temps de résidence des particules dans l'atmosphère lors de ces évènements est notamment observéeThis thesis aims at improving our knowledge of the near and distant sources controlling the exceedance of the regulatory thresholds of air quality, as detected by the air quality monitoring networks, at the strongly industrialized and urban site of Great Dunkirk Area (GDA). This appreciation is notably based on the calculation of a mixing state index of the particles, taking into account the heterogeneity of their elementary composition, this one being related to their residence time in the atmosphere and the distance between the sources and the studied receptor site. To do that, it was firstly necessary to develop a time resolved cascade impactor with high temporal resolution, named "TRAPS", which answered the need to follow the rapid changes observed within the atmospheric particles during pollution episodes. Coupled with a particle size analyser and after individual analysis of the collected particles by electron microscopy (SEM-EDX), TRAPS allows to report the physicochemical evolution of atmospheric particles over time. In the first part of this thesis, laboratory experiments and a field campaign allowed to validate our prototype, to report the dynamics of particle deposition on the impaction stages and to verify the cut-off diameters of the coarse and fine stages of TRAPS, determined respectively at 1.32µm and 0.13µm. A statistical study of PM₁₀ pollution episodes occuring over the GDA was then carried out over 3 years, between 2018 and 2020. It allowed us to identify 12 main types of episodes based on their spatial extent, but also on the local conditions of pollutant dispersion. We were able to identify local episodes and regional episodes observed, either in stationary or dispersive atmospheric conditions. While 78% of the PM₁₀ exceedance days correspond to local episodes, the remaining 22% correspond to pollution plumes with at least a regional extent, with an equal proportion of exceedance days in dispersion and stationary conditions. Except for very localized episodes, a detailed study of these pollutions episodes shows the systematic presence of a period of pollutant accumulation, of about 10 hours, characterized by an important contribution of fine particles (PM₂.₅) except for episodes of limited spatial coverage. The last part of this work consisted in the study of the composition and mixing state of the individual particles collected during pollution events in the GDA in 2021. The campaign allowed the sampling and characterization of 5 pollution episodes, during which TRAPS was deployed in parallel with other instruments providing complementary information on aerosol granulometry, or atmospheric dynamics. Nearly 28000 individual particles were characterized by SEM-EDX. With more than 90% of the samples associated with values of the mixing state index higher than 0.5, it can be said that the particles collected in the GDA during pollution episodes are in general of very heterogeneous composition at the particle scale (internal mixing). Nevertheless, the results show an influence of the local or transported origin of the particles on their chemical composition, but also on the mixing state index. An increasing evolution of this index with the particles residence time during these events is observed
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Steiner, Laure D. "A Study of the fate and transport of estrogenic hormones in dairy effluent applied to pasture soils." Diss., Lincoln University, 2009. http://hdl.handle.net/10182/1306.
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The disposal of waste from agricultural activities has been recognised as a source of environmental contamination by endocrine disrupting chemicals (EDCs). The New Zealand dairy industry produces a large volume of dairy farm effluent, which contains EDCs in the form of estrogens. Most of this dairy farm effluent is applied onto the land for disposal. Groundwater and soil contamination by estrogens following waste application on the land have been reported overseas, but our understanding of the processes and factors governing the fate of estrogens in the soil is poor. Therefore the main goal of the present study was to better understand the fate and transport of estrogens, in particular 17β-estradiol (E2) and estrone (E1) in soil. In order to quantify E1 and E2 in drainage water and soil samples, chemical analysis by gas-chromatography mass-spectrometry (GC-MS) was carried out. This included sample extraction, sample clean-up through silica gel and gel permeation chromatography, and sample extract derivatisation prior to analysis. In order to develop a reliable method to extract estrogens from soil, research was conducted to optimise E1 and E2 extraction conditions by adjusting the number of sonication and shaking events, as well as the volume and type of solvent. Among five solvents and solvent mixtures tested, the best recovery on spiked and aged soil was obtained using an isopropanol/water (1:1) mix. A microcosm experiment was carried out to determine the dissipation rates of E2 and E1, at 8°C and at field capacity, in the Templeton soil sampled at two different depths (5-10 cm and 30-35 cm). The dissipation rates decreased with time and half-life values of 0.6-0.8 d for E1 and 0.3-0.4 d for E2 were found for the two depths studied. A field transport experiment was also carried out in winter, over three months, by applying dairy farm effluent spiked with estrogens onto undisturbed Templeton soil lysimeters (50 cm in diameter and 70 cm deep). The hormones were applied in dairy farm effluent at 120 mg m⁻² for E2 and 137 mg m⁻² for E1. The results of the transport experiment showed that in the presence of preferential/macropore flow pathways 0.3-0.7% of E2 and 8-13% of E1 was recovered in the leachate at the bottom of the lysimeters after 3 months, and 1-7% of the recovered E2 and 3-54% of the recovered E1 was leached within 2 days of application. These results suggest that leaching of estrogens via preferential/macropore flow pathways is the greatest concern for groundwater contamination. In the absence of preferential/macropore flow pathways, a significant amount (> 99.94%) of both hormones dissipated in the top 70 cm of soil, due to sorption and rapid biodegradation. Surprisingly, in all cases, estrogen breakthrough occurred before that of an inert tracer (bromide). This could not be explained by the advection-dispersion transport of estrogens, nor by their presence as antecedent concentrations in the soil. It was therefore suggested that colloidal enhanced transport of estrogens was responsible for the earlier breakthrough of estrogens and caused the leaching of a fraction of the applied estrogens to a soil depth of 70 cm. A two-phase model, adapted from a state-space mixing cell model, was built to describe the observed estrogen transport processes under transient flow. The model takes into account 3 transport processes namely, advection-dispersion, preferential/macropore flow and colloidal enhanced transport. This model was able to successfully describe the estrogen transport observed from the lysimeters.