To see the other types of publications on this topic, follow the link: Solums.
Dissertations / Theses on the topic 'Solums'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Solums.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Fernandez-cornudet, Christelle. "Devenir du Zn, Pb et Cd issus de retombées atmosphériques dans les sols, à différentes échelles d'étude. -Influence de l'usage des sols sur la distribution et la mobilité des métaux-." Phd thesis, INAPG (AgroParisTech), 2006. http://pastel.archives-ouvertes.fr/pastel-00002321.
Full textAbstract:
Dans les études sur le devenir et les impacts de pollutions métalliques dans les sols l'influence de leur usage est encore mal connue. Cette influence a été examinée ici à travers une étude détaillée de comportements de trois métaux polluants, présentant des mobilités différentes: Zn, Cd, et Pb. Cette étude a été menée à la fois dans des horizons de surface d'une petite région affectée par des retombées de poussières métallifères émises par l'industrie métallurgique, ainsi que dans un site comportant deux sols agricoles gérés de manière contrastée. Il s'agit d'un sol sous prairie permanente (PP) et un sol cultivé (CA), situés à une même distance de la source d'émission et développés dans des conditions pédogenétiques semblables. L'objectif principal de ce travail était de quantifier les parts endogènes et exogènes des ETM dans les sols, leurs distributions dans les horizons et dans les compartiments pédologiques (microstructures, agrégats, constituants) et d'identifier les principaux vecteurs d'incorporation. Cette étude a fait appel à des analyses de teneurs totales en éléments (C. organique, Fe, Zn, Pb, Cd,) des études macro- et micromorphologiques, des extractions cinétiques à l'EDTA et des études de la composition isotopique. Un deuxième objectif était de hiérarchiser le rôle des paramètres révélateurs de l'usage des sols sur la distribution et la mobilité des ETM. Ce travail montre que, 40 ans après l'arrêt de l'activité industrielle, la distribution actuelle des teneurs en métaux dans les horizons de surface ne reflète pas celle de retombées atmosphériques attendus selon un modèle simple de distribution en fonction de la distance à la source et des vents dominants. Les teneurs en Zn, Pb et Cd dans les premier 30 cm des sols varient selon l'usage des sols et notamment en fonction du pH, du potentiel redox, de la texture ou encore de l'activité biologique. Ainsi, les horizons de surface de sols acides en forêt auraient perdu plus de 80% du Zn retombé, contre environ 60% de l'horizon A d'un sol sous prairie permanente, suite à la bioturbation lombricienne, et "seulement " 40% pour l'horizon L d'un sol cultivé. Une typologie de secteurs de la zone impactée, pertinente par rapport à la migration de polluants a été proposée à partir de cartographies des rapports Zn/Pb et Cd/Pb. A l'échelle du solum et des horizons, un siècle de pratiques agricoles distinctes a conduit à des phénoformes différents. En particulier, l'activité biologique différente dans les sols PP et CA a modifié le cycle bio-géochimique des métaux et induit des différences dans leurs distributions et mobilité. Les 2 sols présentent en effet des profils de teneurs totales en Zn, Pb et Cd contrastés, avec une rétention de la majeure partie des métaux exogènes dans l'horizon labouré en CA (entre 53% pour Zn et 92% pour Pb et Cd) et une incorporation nettement plus importante dans PP (40% du Zn seulement, 73% du Cd et 82% du Pb exogène sont aujourd'hui présent dans les 26 premiers cm). L'incorporation est significative jusqu'à 80 cm de profondeur sous prairie. A l'échelle des agrégats, l'activité biologique en PP conduit à l'occurrence de trois types de fractions impliquées dans la dynamique des métaux (agrégats de 50-100 μm, 2-20μm, et fraction <2μm), alors que pour CA, seules les fractions 2-20μm et <2μm semblent prioritairement impliquées dans leur rétention et extractabilité. L'analyse de la composition isotopique du Pb sur des échantillons de sol et des extraits EDTA, est un outil performant pour détailler la nature et l'incorporation du Pb exogène. Par cette technique analytique le Plomb exogène sous prairie se retrouve jusqu'à la base du profil et jusqu'à 60cm de profondeur dans le sol sous culture. Cette approche a permis de valider l'ensemble des résultats obtenus à partir des teneurs totales en métaux. Elle souligne la nécessité d'une prise en compte des paramètres pédologiques afin de garantir la représentativité des échantillons étudiés et autoriser une évaluation plus pertinente des risques environnementaux qu'à partir des seules teneurs totales en métaux.
2
De, Munari Annalisa. "Removal mechanisms of organic and inorganic solutes in raw, upland drinking water by nanofiltration : influence of solute-solute and solute-membrane interactions." Thesis, University of Edinburgh, 2012. http://hdl.handle.net/1842/7881.
Full textAbstract:
Nanofiltration (NF) membranes have been applied successfully for the removal of inorganic and organic pollutants, including micropollutants, from drinking water for the past two decades. However, a complete and quantitative understanding of NF removal mechanisms has yet to be achieved. Quantifying the factors governing solute transport and retention by NF is necessary in order to achieve higher treatment efficiency at a lower cost. The aim of this research was to contribute to the current state of the knowledge of the mechanisms of solute retention and transport by NF membranes. The focus was on evaluating the contribution of solute-solute interactions and solute-membrane interactions on solute removal and transport mechanisms. To the knowledge of the author, at the start of this research there was a lack of understanding of the simultaneous impacts of both interactions on the performance of NF membranes, which renders this research novel. To highlight challenges faced by modern membrane plants and identify inorganic and organic pollutants of interest, a study of water quality in Scotland was carried out. Experiments were performed in dead-end stirred cells using two commercial NF membranes, TFC-SR2 and TFC-SR3 provided by Koch, which were extensively characterized. Radiolabeled Endosulfan (ES, 10 μg/L), manganese (5-1,500 mg/L) and Humic Acids (HA, 5-250 mgC/L) were spiked in synthetic water with background electrolyte (1 mM NaHCO3 and 20 mM NaCl). Calcium (Ca, 2.5 mM) was employed in fouling experiments. The influence of the complexation of solutes with HA on solute retention by NF was for the first time quantified for the solute concentrations employed in this study. It was found that manganese retention was influenced by membrane pore size and charge (solute-membrane interactions) and solute speciation (solute-solute interactions). Complexation of manganese and HA (solute-solute interactions) occurred at alkaline conditions but did not enhance manganese retention. At high pH manganese precipitated as solid MnCO3 and these precipitates achieved high retention (99%), even without the presence of HA. ES retention by NF membrane was controlled by size exclusion (solute-membrane interactions). For the tighter TFC-SR3, whose pore size are smaller than the size of ES, ES retention increased in the presence of HA, while for the looser TFC-SR2, whose pores are bigger than ES diameter, ES retention decreased in the presence of HA. For TFC-SR3 increase of ES retention in the presence of HA was due to size exclusion (solute-membrane interactions) and formation of ES-HA complexes (solute-solute interactions). For TFC-SR2 HA-membrane interactions were dominant with respect to solute-solute interactions, increasing membrane molecular weight cut-off (MWCO) and in turn passage of ES. The influence of pressure (5-15 bar) on ES retention in the presence of HA was systematically investigated. Results showed that ES transport through TFC-SR2 and TFC-SR3 was dominated by convection. For the tighter TFC-SR3 lower permeate flux was responsible for the increase of retention with pressure, while for the looser TFC-SR2 higher permeate flux increased concentration polarisation, decreasing retention with pressure. The presence of HA lowered the permeate flux, resulting in a less pronounced variation of retention with pressure for TFC-SR2 and in constant retention for TFC-SR3. The impact of manganese scaling on the performance of NF membranes was investigated at neutral pH. The effects of inorganic precipitates on flux and solute retention by NF have been so far scarcely studied and the impact of inorganic scaling on micropollutant retention by NF is unknown. Findings from this research indicated that manganese deposits did not foul the membranes but on the contrary enhanced their flux and prevented fouling by HA and Ca. The retention of ES, manganese and HA by membranes through which manganese was previously filtered was found to decrease with respect to solute retention by virgin membranes. Manganese filtration was shown to increase membrane MWCO and hydrophilicity. It was proposed that manganese-membrane interactions caused swelling of the membrane active layer by increasing the membrane free volume. The findings of this research indicated the importance of investigating simultaneously the impacts of solute-solute interactions and solute-membrane interactions to understand and explain transport and removal mechanisms of organic and inorganic contaminants by NF.
3
Abbas, Farhat. "The effect of surface-solute interactions on the transport of solutes through porous media." Thesis, University of Newcastle Upon Tyne, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324867.
Full text
4
Srinivasan, C. "Analysis Of Solute Transport In Porous Media For Nonreactive And Sorbing Solutes Using Hybrid FCT Model." Thesis, Indian Institute of Science, 2000. http://hdl.handle.net/2005/218.
Full textAbstract:
The thesis deals with the numerical modeling of nonreactive and nonlinearly sorbing solutes in groundwater and analysis of the effect of heterogeneity resulting from spatial variation of physical and chemical parameters on the transport of solutes. For this purpose, a hybrid flux corrected transport (FCT) and central difference method based on operator-split approach is developed for advection-dispersion solute transport equation. The advective transport is solved using the FCT technique, while the dispersive transport is solved using a conventional, fully implicit, finite difference scheme. Three FCT methods are developed and extension to multidimensional cases are discussed.
The FCT models developed are anlaysed using test problems possessing analytical solutions for one and two dimensional cases, while analysing advection and dispersion dominated transport situations. Different initial and boundary conditions, which mimic the laboratory and field situations are analysed in order to study numerical dispersion, peak cliping and grid orientation. The developed models are tested to study their relative merits and weaknesses for various grid Peclet and Courant numbers. It is observed from the one dimensional results that all the FCT models perform well for continuous solute sources under varying degrees of Courant number restriction. For sharp solute pulses FCT1 and FCT3 methods fail to simulate the fronts for advection dominated situations even for moderate Courant numbers. All the FCT models can be extended to multidimensions using a dimensional-split approach while FCT3 can be made fully multidimensional. It is observed that a dimensional-split approach allows use of higher Courant numbers while tracking the fronts accurately for the cases studied. The capability of the FCT2 model is demonstrated in handling situations where the flow is not aligned along the grid direction. It is observed that FCT2 method is devoid of grid orientation error, which is a common problem for many numerical methods based on Cartesian co-ordinate system.
The hybrid FCT2 numerical model which is observed to perform better among the three FCT models is extended to model transport of sorbing solutes. The present study analyses the case of nonlinear sorption with a view to extend the model for any reactive transport situation wherein the chemical reactions are nonlinear in nature. A two step approach is adopted in the present study for coupling the partial differential equation governing the transport and the nonlinear algebraic equation governing the equilibrium sorption. The suitability of explicit-implicit (EI - form) formulation for obtaining accurate solution coupling the transport equation with the nonlinear algebraic equation solved using a Newton-Raphson method is demonstrated. The performance of the numerical model is tested for a range of Peclet numbers for modelling self-sharpening and self-smearing concentration profiles resulting from nonlinear sorption. It is observed that FCT2 model based on this formulation simulates the fronts quite accurately for both advection and dispersion dominated situations. The delay in the solute mobility and additional dispersion are analysed varying the statistical parameters characterising the heterogeneity namely, correlation scale and variance during the transport of solutes and comparisons are drawn with invariant, cases. The impact of dispersion during the heterogeneous transport is discussed.
5
Bezerra, André Herman Freire. "Mechanistic numerical modeling of solute uptake by plant roots." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/11/11152/tde-28042016-104725/.
Full textAbstract:
A modification in an existing water uptake and solute transport numerical model was implemented in order to allow the model to simulate solute uptake by the roots. The convection-dispersion equation (CDE) was solved numerically, using a complete implicit scheme, considering a transient state for water and solute fluxes and a soil solute concentration dependent boundary for the uptake at the root surface, based on the Michaelis- Menten (MM) equation. Additionally, a linear approximation was developed for the MM equation such that the CDE has a linear and a non-linear solution. A radial geometry was assumed, considering a single root with its surface acting as the uptake boundary and the outer boundary being the half distance between neighboring roots, a function of root density. The proposed solute transport model includes active and passive solute uptake and predicts solute concentration as a function of time and distance from the root surface. It also estimates the relative transpiration of the plant, on its turn directly affecting water and solute uptake and related to water and osmotic stress status of the plant. Performed simulations show that the linear and non-linear solutions result in significantly different solute uptake predictions when the soil solute concentration is below a limiting value (Clim). This reduction in uptake at low concentrations may result in a further reduction in the relative transpiration. The contributions of active and passive uptake vary with parameters related to the ion species, the plant, the atmosphere and the soil hydraulic properties. The model showed a good agreement with an analytical model that uses a linear concentration dependent equation as boundary condition for uptake at the root surface. The advantage of the numerical model is it allows simulation of transient solute and water uptake and, therefore, can be used in a wider range of situations. Simulation with different scenarios and comparison with experimental results are needed to verify model performance and possibly suggest improvements.<br>Uma modificação em um modelo existente de extração de água e transporte de solutos foi realizada com o objetivo de incluir nele a possibilidade de simular a extração de soluto pelas raízes. Uma solução numérica para a equação de convecção-dispersão (ECD), que utiliza um esquema de resolução completamente implícito, foi elaborada e considera o fluxo transiente de água e solutos com uma condição de contorno à superfície da raiz de extração de soluto dependente de sua concentração no solo, baseada na equação de Michaelis- Menten (MM). Uma aproximação linear para a equação de MM foi implementada de tal forma que a ECD tem uma solução linear e outra não-linear. O modelo considera uma raiz singular com geometria radial sendo sua superfície a condição de contorno (limite) de extração e sendo o limite extremo a meia-distância entre raízes vizinhas, função da densidade radicular. O modelo de transporte de soluto proposto inclui extração de soluto ativa e passiva e prediz a concentração de soluto como uma função do tempo e da distância à superfície da raiz, além de estimar a transpiração relativa da planta, que por sua vez afeta a extração de água e solutos e é relacionado com a condição de estresse da planta. Simulações mostram que as soluções linear e não-linear resultam em predições de extração de solutos significativamente diferentes quando a concentração de solutos no solo está abaixo de um valor limitante (Clim). A redução da extração em baixas concentrações pode resultar em uma redução adicional na transpiração relativa. As contribuições ativa e passiva da extração de solutos variam com parâmetros relacionados à espécie de íon, à planta, à atmosfera e às propriedades hidráulicas do solo. O modelo apresentou uma boa concordância com um modelo analítico que aplica uma condição de contorno linear, à superfície da raiz, de extração de solutos dependente da concentração no solo. A vantagem do modelo numérico sobre o analítico é que ele permite simular fluxos transientes de água e solutos, sendo, portanto, possível simular uma maior gama de situações. Se faz necessário simulações com diferentes cenários e comparações com dados experimentais para se verificar a performance do modelo e, possivelmente, sugerir melhorias.
6
Nguyen, Thi Vi Na. "Étude des mécanismes de transferts des solutés neutres et chargés en nanofiltration dans des milieux hydro-alcooliques." Thesis, Rennes 1, 2018. http://www.theses.fr/2018REN1S100/document.
Full textAbstract:
L'extraction de biomolécules à partir de ressources renouvelables devient l'un des thèmes clés dans les domaines de la biotechnologie, de la cosmétologie et de la pharmacie. Pour minimiser la consommation de solvant organique et augmenter l'efficacité, l'extraction avec des mélanges eau/alcool semble être une approche prometteuse. De plus, des étapes supplémentaires de purification et de concentration sont généralement nécessaires pour enrichir le milieu avec les molécules cibles. La nanofiltration (NF) est une technique de séparation idéale et durable pour de telles opérations car elle est propre, sobre et sûre. Il existe néanmoins peu de littérature concernant la NF dans ces mélanges eau/éthanol. Cette étude vise à mieux comprendre les mécanismes de transfert qui régissent la sélectivité dans ces milieux. Dans un premier temps une étude fondamentale est réalisée sur la NF dans des mélanges eau/ alcool seuls ou en présence de solutés neutres et/ou chargés. Les résultats obtenus montrent que lorsque la teneur en alcool augmente, la membrane gonfle, le rayon des pores augmente mais la résistance intrinsèque reste constante. Les mécanismes de transfert bien connus en milieux aqueux (exclusion stérique, interaction électrostatique, interaction diélectique) et en milieux organiques (interactions hydrophobes, affinité soluté-membrane-solvant) sont tous présents dans des mélanges eau/alcool mais leur intensité relative semble être différente. Différents modèles (Spiegler-Kedem & Film, Hydrodynamique & Film, Solution-Diffusion & Film, Pore-Flow & Film, Steric Electric and Dielectric Exclusion) ont été utilisés pour modéliser les rétentions et estimer les paramètres de transfert<br>The extraction of bio-molecules from renewable resources is emerging as one of a key topics in the fields of biotechnology, cosmetology and pharmacy. To minimize the organic solvent consumption, as well as to increase the efficiency, extraction by water/alcohol mixtures appears to be a promising approach. Moreover, additional purification and concentration steps are generally required to enrich the medium with the target molecules. Nanofiltration is a de-facto separation technique for such operations because it is clean, sober and safe. Unfortunately, there is few literature on the transfer of water/ethanol mixtures regarding nanofiltration. This study aims to better understand the transfer mechanisms that govern selectivity in these media. At the first step, a fundamental study is realized on nanofiltration in water/alcohol mixtures alone or with the presence of neutral or charged solutes. The obtained results show that when the alcohol content increases, the membrane is swelling, the pore radius increases but the intrinsic resistance is still constant. The well-known transfer mechanisms in aqueous media (steric exclusion, electric interaction, dielectric interaction) and in organic media (hydrophobic interaction, affinity solute-membrane-solvent) are all present in the water/alcohol mixtures, but relative intensity appears to be different. Different models (Spiegler-Kedem & Film, Hydrodynamics & Film, Solution-Diffusion & Film, Pore-Flow & Film, Electric Steric and Dielectric Exclusion) were used to model the retentions and estimate the transfer parameters
7
Liu, Weidong. "High density solids downflow gas-solids reactors." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0001/MQ42081.pdf.
Full text
8
Brilhante, Jean Carlos de AraÃjo. "ContribuiÃÃo de solutos orgÃnicos e inorgÃnicos no potencial osmÃtico de folhas de atriplex nummularia submetidas ao NaCl, SECA E PEG." Universidade Federal do CearÃ, 2006. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=2190.
Full textAbstract:
Uma das caracterÃsticas fisiolÃgicas mais importantes das halÃfitas pertencentes ao gÃnero Atriplex à a enorme habilidade de acumular solutos orgÃnicos e inorgÃnicos com o intuito de se ajustar osmoticamente em condiÃÃes de elevada salinidade e deficiÃncia hÃdrica. Contudo estudos compreensivos sobre a contribuiÃÃo relativa desses solutos inorgÃnicos e orgÃnicos no
ajustamento osmÃtico de folhas dessas halÃfitas ainda sÃo poucos explorados na literatura. Esse trabalho pretende pela primeira vez na literatura fazer um estudo detalhado, da participaÃÃo e da contribuiÃÃo relativa da maioria dos solutos orgÃnicos e inorgÃnicos no potencial osmÃtico de folhas de Atriplex nummularia, submetidas a concentraÃÃes crescentes de NaCl, ciclos sucessivos de seca e ao polietileno glicol (PEG). Para responder as questÃes acima mencionadas foram conduzidos trÃs grandes experimentos seqÃenciais. No primeiro experimento, mudas de Atriplex nummularia com quatro meses de idade, foram cultivadas em vasos de argila contendo como
substrato areia, sendo irrigadas a cada dois dias com soluÃÃo contendo concentraÃÃes crescentes de NaCl (0, 100, 200, 300 e 400 mmol L-1) durante 120 dias. O experimento foi realizado em condiÃÃes de casa de vegetaÃÃo. No segundo experimento, mudas de A. nummularia, com idade de 18 meses foram transplantadas para recipientes de polietileno contendo 5.0 kg de vermiculita, em condiÃÃes de casa de vegetaÃÃo, onde foram submetidas aos seguintes tratamentos (Controle; seca; NaCl + seca; NaCl) por trÃs ciclos sucessivos de seca-reidrataÃÃo (3 semanas) seguido de uma recuperaÃÃo no final do Ãltimo ciclo (apÃs 48 h). No terceiro experimento, plÃntulas de A.nummularia, com idade de dois meses foram transplantadas para cultivo hidropÃnico em vasos plÃsticos com capacidade para 0,8 em sala de crescimento sob condiÃÃes controladas onde sofrerÃo um prÃ-condicionamento com ou sem NaCl por duas semanas. ApÃs foram submetidas aos seguintes tratamentos (controle; PEG; NaCl; NaCl + PEG). Em conclusÃo, os resultados da presente investigaÃÃo demonstram que as plantas de Atriplex nummularia foram capazes de manter o seu crescimento mesmo em condiÃÃes de alta salinidade, principalmente pela capacidade de manutenÃÃo de seu status hÃdrico. Os resultados tambÃm sugerem que a GB Ã o maior soluto orgÃnico envolvido com o ajustamento osmÃtico (AO) do citoplasma e que sua acumulaÃÃo parece ser uma resposta adaptativa ao estresse provocado pelo NaCl. Em adiÃÃo, o Ãons salinos Na+ e Cl- contribuÃram para a maioria do AO das folhas submetidas ao NaCl. O impacto relativo do K+ sobre o AO das folhas foi reduzido consideravelmente com o aumento da dose externa de NaCl. Os resultados evidenciam tambÃm que o prÃ-condicionamento com NaCl influenciou positivamente no crescimento de Atriplex nummularia, em condiÃÃes de seca,
evidenciado pelo maior acÃmulo de massa seca e melhor status hÃdrico das folhas. Dentre os solutos inorgÃnicos analisados, o Na+ e o Cl- foram os que mais contribuÃram para a osmorregulaÃÃo das folhas em condiÃÃes de deficiÃncia hÃdrica. Enquanto, GB foi o soluto orgÃnico mostrou o maior percentual de contribuiÃÃo para o potencial osmÃtico. Entretanto os
resultados mostraram que o prÃ-condicionamento das plÃntulas de Atriplex nummularia com NaCl nÃo foram capazes de atenuar os efeitos induzidos pelo PEG.
9
Neale, Peta Anne. "Influence of solute-solute interactions on membrane filtration." Thesis, University of Edinburgh, 2009. http://hdl.handle.net/1842/4106.
Full textAbstract:
An understanding of solute-solute interactions is essential for aquatic systems as this can affect the fate and behaviour of micropollutants in the environment and engineered systems. Despite the importance of solute-solute interactions there is a general lack of understanding which may be attributed to the fact that many engineering models overlook solute-solute interactions and that the quantification of such interactions is inherently difficult. When solute-solute interactions are considered, they are often studied at unrepresentative concentrations and do not consider the influence of organic matter type or solution chemistry. Steroidal hormones, such as estradiol and estrone, were selected as model micropollutants as they are ubiquitous in the aquatic environment due to constant introduction of wastewater effluent, and can have implications for growth and development of organisms including impaired fertility and behavioural abnormalities. The purpose of this study was to develop a methodology to quantify solute-solute interactions at environmental concentrations, and to determine the implications of such interactions in membrane filtration. A solid-phase microextraction (SPME) technique was developed to quantify solutesolute interactions at environmental (low) concentrations. Using SPME, organic matter-water partition coefficients (log KOM) were measured for a range of steroidal hormones including estradiol, estrone, progesterone and testosterone with different organic matter types such as humic acid. The dominant mechanism of hormoneorganic matter interactions was identified as hydrogen bonding. In the case of estrone and progesterone the log KOM values were significantly influenced by organic matter type and concentration, as well as solution chemistry. No difference was observed for estradiol and testosterone due to generally weaker sorption to organic matter. Previous studies have indicated that the presence of organic matter can alter micropollutant retention in membrane filtration. Much of the current literature focuses on solute-membrane interactions, as the influence of solute-solute interactions are typically difficult to determine in membrane filtration. Therefore, hormone-organic matter interactions were studied to determine if this interaction had an influence on hormone removal by ultrafiltration (UF) using a range of molecular weight cut-off (MWCO) membranes. The results indicated increased retention of estrone in the presence of humic acid, while organic matter concentration and solution chemistry influenced retention by affecting solute-solute interactions. The findings of this study indicate the importance of solute-solute interactions in membrane filtration and experimental log KOM results were used to quantify the findings and elucidate the influences of 1) membrane sorption, 2) solute-solute interactions and 3) solute-foulant interactions. Further, the removal of steroidal hormones using a magnetic ion exchange (MIEX®) resin with a range of MWCO UF membranes was studied as such sorbents can be used to improve micropollutant removal in wastewater treatment. Greater removal with IX-UF was observed compared to UF alone and the main hormone removal mechanisms were sorption to MIEX® and solute-fouling interactions. The findings of this study indicate that it is indeed possible to quantify solute-solute interactions at environmental concentrations using SPME, with hydrogen bonding being the main mechanism of interaction for steroidal hormones and organic matter. Further, micropollutant retention by membrane filtration can be influenced by solutesolute interactions.
10
Pinto, Maria do Rosario. "Perfect solids." Thesis, University of Southampton, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358006.
Full text
11
Mandale, Stephen John. "Nanofiltration of multi-solute systems : solute interactions and theory." Thesis, Swansea University, 2005. https://cronfa.swan.ac.uk/Record/cronfa42669.
Full textAbstract:
From the outset, membrane researchers have studied the behaviour and governing processes of membrane separations. Theoretical representation of membrane transport systems is central to membrane research and the most recent investigations have considered single and binary solute systems of charged and uncharged species. A gap in the research was detected with respect to systems of combined charged (dissociated) and uncharged (non-dissociated) species. Thus these systems were explored from both a practical-experimental and theoretical perspective. The result of experimental investigation into combined systems of charged/uncharged solutes, was an observation of negative rejections for uncharged solutes in the presence of high salt concentrations. This is a phenomenon that was not observed elsewhere and in general the rejection of uncharged solutes was attributed to steric factors hence a direct interaction between salts and neutral solutes was not suggested. The reliability of the negative rejection observations was established through a discussion of experimental error and a consideration of concentration polarisation. It was found that the error was negligible and that the measured negative rejections (approximately -10% in some cases) were not attributable to variation in the results caused by external influences. An analysis of concentration polarisation only served to amplify the negative rejection observed, since real rejection (that at the membrane surface) exhibited greater negativity than the observed rejection. The observed phenomenon was discussed with respect to current forms of membrane transport theories. The semi-black box technique proposed by Spiegler and Kedem and later modified by Van der Bruggen and co-workers was found to provide a reasonable fit of the experimental data where valance was taken to be a non-integer fitting parameter. Errors in the Fortran implementation of the Bowen and Welfoot development of the Donnan Steric Partitioning Model (DSPM) prevented this transport theorem from being explored in relation to the measured phenomenon. Thus it was a recommendation of this work that this theory should be considered in more depth.
12
Constantinescu, Dario. "Analyse et amélioration d’un modèle mécaniste de croissance et composition du fruit : Etude de la variabilité génétique des mécanismes de croissance du fruit, conception d’idéotypes et analyse des effets des transferts d’eau et de la concentration des solutés sur la croissance du fruit Model-Assisted Estimation of the Genetic Variability in Physiological Parameters Related to Tomato Fruit Growth under Contrasted Water Conditions Model-assisted analysis of the pedicel-fruit system suggests a fruit sugar uptake regulation and a water saving strategy." Thesis, Avignon, 2019. http://www.theses.fr/2019AVIG0716.
Full textAbstract:
Développer la connaissance des réponses du développement des fruits aux pratiques agricoles et aux conditions environnementales est important, depuis les sélectionneurs jusqu’aux producteurs. Cela soutiendrait la conception de pratiques agricoles permettant d’augmenter le rendement et la qualité des fruits et d’adapter la production fruitière au changement climatique, afin de satisfaire la croissance de la demande alimentaire. Le but de cette thèse était d'utiliser et d'améliorer un modèle mécaniste de croissance du fruit pour explorer la variabilité génétique de la tomate, concevoir des idéotypes de tomate plus résistants à la sécheresse, mettre en évidence des modes de circulation de l’eau et des sucres dans le système pédicel-fruit au cours de la journée, et étudier les effets des variations des concentrations en solutés dans la pulpe des fruits sur la croissance, qui détermine la qualité des fruits à la récolte. Les modèles développés ont permis de décrire de manière adéquate les processus biophysiques et métaboliques déterminant la croissance des fruits et la composition des solutés. Les résultats de simulation du modèle obtenus suggèrent que la conductivité pédiculaire et l'absorption active des sucres pourraient être des mécanismes clés pour déterminer la variabilité génétique des fruits et devraient être maximisés dans la recherche d'idéotypes. De plus, les résultats obtenus suggèrent que la régulation des flux d'eau peut générer une régulation de l'absorption diurne de sucre par le fruit et pourrait prévenir la perte d'eau au travers de la recirculation entre le xylème et le phloème et entre le phloème et l’apoplasme. Enfin, les résultats obtenus à partir d'un modèle intégré incluant la description de la croissance des fruits et du métabolisme des solutés de fruits ont mis en évidence que la variation des concentrations en acides et en minéraux due aux processus d'accumulation et de dilution pourrait avoir un impact non négligeable sur la croissance des fruits. Les études présentées dans cette thèse ont mis en évidence que l'estimation des paramètres physiologiques de la croissance des fruits et les techniques de conception et de calibration des modèles devraient être améliorées pour les rendre plus adaptés à la conception de meilleurs pratiques agricoles<br>Developing knowledge on fruit development responses to agricultural practices and environmental conditions is important from breeders to growers. Indeed, this would support the design of agricultural practices that could increase fruit yield and quality and adapt fruit production to climate change, for satisfying the increasing food demand. The aim of this thesis was to use and improve a mechanistic model of fruit growth for exploring the genetic variability of tomato growth in fresh and dry mass, designing drought-resistant tomato ideotypes, underlining patterns of diurnal water and sugars flows in the pedicel-fruit system, and studying the effects on fruit growth of the variations of fruit pulp solutes concentrations that determine fruit quality at harvest. The models developed allowed to describe in an adequate way biophysical and metabolic processes determining fruit growth and solutes composition. The obtained model simulation results suggested that pedicel conductivity and sugars active uptake could be key mechanisms in determining the fruit genetic variability and should be maximized in the research of ideotypes. In addition, the obtained results suggested that water flows regulation may generate a diurnally regulated fruit sugar uptake and could prevent water loss through water recirculation between xylem and phloem and between phloem and apoplast. Finally, the results obtained from an integrating model approach including the description of fruit growth and fruit solutes metabolism highlighted that acids and minerals concentrations variation due to both accumulation and dilution processes could have a non-negligible impact on fruit growth. The works presented in this thesis have highlighted that the estimation of the fruit growth physiological parameters and the techniques of models conception and calibration should be improved to make them increasingly suitable for the design of better-suited agricultural practices
13
Ottman, M. J. "Solum Barley Nitrogen and Phosphorous Fertilizer Trial." College of Agriculture, University of Arizona (Tucson, AZ), 1995. http://hdl.handle.net/10150/201446.
Full text
14
Etchebers, Olivier. "Etude pluricontextuelle et pluridimensionnelle de la mobilité des métaux lourds (Cd, Ni, Pb) dans les sols." Pau, 2004. http://www.theses.fr/2004PAUU3004.
Full textAbstract:
La mobilité des métaux lourds est étudiée dans trois contextes de contamination, chacun à une échelle différente. Le premier est l'épandage de boues de station d'épuration sur sol forestier. Les processus sont accélérés par centrifugation, en microcosme. Malgré plusieurs mois d'évolution simulée, la migration des métaux (Cd, Ni, Pb) reste très limitée, vraisemblablement par affinité avec la matière organique accumulée en surface. Le deuxième est réalisé en mésocosme, à partir d'une terre agricole dopée en Pb. Après plusieurs mois en milieu extérieur, le Pb est retenu dans le solide. Il est adsorbé sur les particules organiques et argileuses (montmorillonite) mais reste potentiellement mobilisable. Le troisième concerne un aquifère sous un site industriel (macrocosme) pollué en Cu et H2SO4. L'acidité favorise la solubilité du Cd et du Pb. Cependant, le pouvoir tampon du solide entraîne la précipitation du Cu et du Fe; et l'immobilisation du Cd et du Pb par adsorption ou coprécipitation<br>The mobility of heavy metals is studied on three cases of contamination, each one at a different scale. The first one deals with spreading of sewage sludge on forest soils. Processes are accelerated under centrifugation, at microcosm scale. Despite several months of simulated evolution, migration of heavy metals (Cd, Ni, Pb) is quite limited, probably by affinity with organic matter accumulated at the surface. The second one is run at mesocosm scale, using an agricultural soil spiked with Pb. After several months outdoor, Pb is retained within the solid. It is adsorbed on organic and clay (montmorillonite) particles, but remains under a potentially soluble form. The third one corresponds to an aquifer underlying an industrial site (macrocosm) polluted by Cu and H2SO4. Acidity enhances the solubility of Cd and Pb. However, the buffer capacity of the solid induces the precipitation of Cu and Fe; and the fixation of Cd and Pb by adsorption or coprecipitation
15
Yang, Wei. "Solids phase chromatography." Thesis, University of Leeds, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.505060.
Full textAbstract:
The present study focuses on the development of a novel technique, namely Solids Phase Chromatography (SPC), for particle classification and size analysis. SPC is a fractionation based technique and utilises a separation channel to fractionate the particle samples into sub-fractions according to their sizes. Subsequently, the products may be analysed by various detectors and recovered for other investigations.
16
Cline, John Michael. "A Solemn Assembly." Digital Commons @ East Tennessee State University, 2005. https://dc.etsu.edu/etd/1012.
Full textAbstract:
A group of oil paintings completed in partial requirement of my MFA degree is discussed. The paintings are on wood panels and are the result of a combination of old master techniques of under-painting and glazing and more contemporary approaches to the painting process. Each painting represents a particular concept or event from Mormon theology; whereas, the pictorial structure is inspired by Medieval manuscript painting. Thus, this body of work is a synthesis between two worldviews existing centuries apart, yet sharing certain core values and beliefs.
17
Schwertner, Diogo Vanderlei. "Produção de tomateiro cultivado com acrescent solus®." Universidade Federal de Santa Maria, 2012. http://repositorio.ufsm.br/handle/1/5060.
Full textAbstract:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior<br>The objectives of this study were: verify the adequation to the presuppositions of the
mathematical model and, identify data transformation for productive and morphological
variables of tomato in experiments in plastic tunnel and in field, considering each harvest date
and grouped harvests during spring-summer and autumn-winter seasons; and, to evaluate the
effect of the application of Acrescent Solus® in complementation and/or substitution to the
mineral fertilization in coverage over productive and morphological variables, quality of fruit
and color of leaves of tomato cultivated in plastic tunnel and in field during springsummer
and autumn-winter seasons. Two experiments were conducted in plastic tunnel
(spring-summer and autumn-winter) and one in field (spring-summer), both in a randomized
block design with three replications in a bifactorial (2x4), with four additional controls. The
tests of: non-additivity of Tukey, Lilliefors, Bartlett and Run Test, were used, respectively, for
verify the adequation to the presuppositions of: additivity of the model, normality,
homogeneity and randomness of errors. In cases of violation, the data were transformed and,
submitted again to the analysis of the presuppositions of the mathematical model. The
productive and morphological variables of tomato present adequation to the presupposition of
additivity of the model. Violations of the productive and morphological variables occur to the
presupposition of: normality, homogeneity and randomness of errors. The grouping of all
harvests for analysis provides adequation of productive and morphological variables to the
presuppositions of normality and homogeneity of errors. The data transformation that
provides more proportion of adequation of productive and morphological variables to the
presuppositions of normality, homogeneity and randomness of errors is the square root. In the
spring-summer, the Acrescent Solus® does not alter the productive and morphological
variables and, the quality of fruits of tomato, while, in the autumn-winter, it reduces the
length, the width and the mass of fruits and, also, it does not alters the quality of fruits. The
increase of the dose of Acrescent Solus®, combined with the mineral fertilization in coverage
results in intensification of the green color of leaves, from the second and fourth harvest fruit
in the spring-summer and autumn-winter, respectively, nevertheless, without showing
favorable correlation with the expression of productive and morphological variables of
tomato.<br>Os objetivos deste estudo foram: verificar o atendimento às pressuposições do modelo
matemático e, identificar transformações de dados para variáveis produtivas e morfológicas
de tomateiro em experimentos em túnel plástico e em campo, considerando cada data de
colheita e colheitas agrupadas na primavera-verão e outono-inverno; e, avaliar o efeito da
aplicação de Acrescent Solus® em complementação e/ou substituição à adubação mineral em
cobertura sobre variáveis produtivas, morfológicas, de qualidade de frutos e de coloração de
folhas de tomateiro cultivado em túnel plástico e em campo na primavera-verão e outonoinverno.
Dois experimentos foram conduzidos em túnel plástico (primavera-verão e outonoinverno)
e um em campo (primavera-verão), ambos no delineamento de blocos ao acaso com
três repetições em um bifatorial (2x4), com quatro testemunhas adicionais. Para verificar o
atendimento às pressuposições de: aditividade do modelo, normalidade, homogeneidade e
aleatoriedade dos erros foram utilizados, respectivamente, os testes de: não aditividade de
Tukey, Lilliefors, Bartlett e de Sequência. Nos casos de violação, os dados foram
transformados e, novamente submetidos à análise das pressuposições do modelo matemático.
As variáveis produtivas e morfológicas de tomateiro apresentam atendimento ao pressuposto
de aditividade do modelo. Ocorrem violações das variáveis produtivas e morfológicas às
pressuposições de: normalidade, homogeneidade e aleatoriedade dos erros. O agrupamento de
todas as colheitas para análise proporciona atendimento das variáveis produtivas e
morfológicas aos pressupostos de normalidade e homogeneidade dos erros. A transformação
que possibilita maior proporção de atendimento das variáveis produtivas e morfológicas aos
pressupostos de normalidade, homogeneidade e aleatoriedade dos erros é a raiz quadrada. Na
primavera-verão o Acrescent Solus® não influencia as variáveis produtivas, morfológicas e
de qualidade dos frutos de tomateiro, enquanto no outono-inverno reduz o comprimento, a
largura e a massa de frutos e, também não influencia a qualidade de frutos. O aumento da
dose de Acrescent Solus®, combinada com a adubação mineral em cobertura resulta em
intensificação da coloração verde das folhas, a partir da segunda e quarta colheita de frutos na
primavera-verão e outono-inverno, respectivamente, porém, sem apresentar correlação
favorável com a expressão das variáveis produtivas e morfológicas de tomateiro.
18
Mercury, Lionel. "Equilibres minéraux-solutions en milieu non saturé des sols : thermodynamique de l'eau capillaire et modélisation physicochimique." Poitiers, 1997. http://www.theses.fr/1997POIT2348.
Full textAbstract:
L'etude des equilibres mineraux - solution dans le domaine non sature des sols necessite de considerer l'etat particulier de l'eau. L'eau liquide liee, en conditions capillaires, est soumise a une pression generalement negative, en tout cas inferieure a celle de l'atmosphere. Une methode de calcul de toutes les proprietes thermodynamiques de l'eau, fondee sur cette realite physique, est proposee et discutee au chapitre 1, a partir de la regression des donnees etablies a pression positive. Le chapitre 2 presente le calcul des proprietes thermodynamiques de la plupart des polymorphes de la glace. La notion d'<<<>ice-like water<>>> peut alors etre clairement definie, au chapitre 3, et appliquee a l'eau de constitution des hydrates et des hydroxydes. . . .
19
Knoth, de Zarruk Katrin. "Transferts réactifs et mobilité de la matière organique dissoute dans les sols." Avignon, 2007. http://www.theses.fr/2007AVIG0605.
Full textAbstract:
Les MOD sont ubiquistes dans les sols, les eaux et les déchets organiques et jouent un rôle important dans la complexation et le co-transport des métaux et de polluants organiques. Par conséquent, la qualité de l'eau potable peut être mise en danger. Les MOD sont très variables dans l'espace et le temps ce qui complique leur caractérisation. Une nouvelle approche des MOD, une approche de bas en haut est présentée qui se concentre sur la composition moléculaire des MOD. Une recherche exhaustive de la littérature a été effectuée pour démontrer l'importance des composés individuels simples dans les processus environnementaux. La dialyse des MOD de sources différentes a révélé une grande variabilité des échantillons concernant la composition et la taille moléculaire. Quatre-vingt, 70, 50 et 40% du carbone organique total (COT) ont été trouvés dans les fractions d'une taille moléculaire faible de vinasse, compost de feuilles, sol et fumier de volaille, respectivement. Plus de 40% du COT dans la vinasse et le compost de feuilles ont été attribués à la fraction ayant un poids moléculaire <500 Da révélant l'abondance des petits composés. Pour pouvoir mieux estimer la vraie capacité de co-transport des composés individuels, des expériences de colonne ont été effectuées<br>DOM is present in all soils, waters and organic wastes and can be important in binding and co-transporting metals and organic polluants, there fore endangering the quality of potable waters. Dom is higly variable over space and time, which complicates its characterization. A new approach to DOM, a bottom-up approach is presented that concentrates on the molecular composition of DOM. By the means of a thorough literature research, the importance of simple individual compounds in environmental processes is demonstrated. Dialysis of DOM from different sources revealed a great variability of DOM samples in respect of molecular composition and size. Eighty, 70, 50 and 40% of the total organic carbon (TOC) was found in the fractions with low molecular weight in vinasse, leaf compost, soil and chicken manure, respectively. More than 40% of the TOC in vinasse and leaf compost belonged to the fraction with a molecular weight <500 Da, revealing the abundance of small weight in vinasse, suggesting a potential co-transport of copper by low molecular weight compounds. In order to enable us to better estimate the true co-transport of copper by low molecular weight compounds, column experiments were conducted to determine sorption and biodegradation dynamics for a set of selected compounds (glucose, glucosamine, glucuronic acid, alanine, citric acid, acetic acid, caffeic acid, dextran). Results showed that functional group content plays a major role in compound mobility. Even seemingly similar molecules that only differ in one functional group are sorbed and biodegraded in very different manners. Afters combining metal-complexing with sorption and biodegradation parameters, acetic acid was found to be the compound with the highest co-transport potential
20
Wang, Hao. "Theoretical strength of solids." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/42747.
Full textAbstract:
Theoretical strength of solids is defined as the ultimate strength beyond which plastic deformation, fracture, or decohesion would occur. Understanding the microscopic origin from quantum mechanics and thermoelastic formulation is of great importance to mechanical properties and engineering design of various solids. While quite a few theory models have been made in the past century by several generations of scientists, including Frankel and Born, a general and convincing framework has not been fully established. We study this issue from three respects: (1) Unify various elastic stability criteria for solids that determine an upper bound of theoretical strength; (2) with ab initio method, we test the elastic stability conditions of crystal Au. The phenomenon of bifurcation is observed: under hydrostatic expansion, the rhombohedral modulus reaches zero first of all; while under uniaxial tensile stress, the tetragonal shear modulus first reaches zero; (3) propose a nonlinear theoretical formulation of stability criterion. As an analytic method, this scheme is quite simple, in the mean time, it saves computation resource.
21
Kwetkus, Bernhard Andreas. "Contact electrification of solids /." [S.l.] : [s.n.], 1992. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=9788.
Full text
22
Pronk, Sander. "Disorder in entropic solids." [S.l : Amsterdam : s.n] ; Universiteit van Amsterdam [Host], 2003. http://dare.uva.nl/document/86583.
Full text
23
Pattenden, Paul Adam. "Muon studies of solids." Thesis, University of Oxford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361930.
Full text
24
Nichol, A. C. "Infrared spectroscopy of solids." Thesis, University of Oxford, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308601.
Full text
25
Cook, M. I. "Magnetic resonance in solids." Thesis, University of Oxford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.253004.
Full text
26
O'Connell, Andrew John. "Magnetic resonance in solids." Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.305439.
Full text
27
Chadwick, Alan V. "Diffusion in nanocrystalline solids." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-195769.
Full textAbstract:
Enhanced atomic migration was an early observation from experimental studies into nanocrystalline solids. This contribution presents an overview of the available diffusion data for simple metals and ionic materials in nanocrystalline form. It will be shown that
enhanced diffusion can be interpreted in terms of atomic transport along the interfaces, which are comparable to grain boundaries in coarse-grained analogues. However, the method of sample preparation is seen to play a major role in the experiments and there are still many gaps in understanding the detailed mechanisms of diffusion in these systems.
28
Madden, Timo Michael. "Regular and perfect solids." Thesis, University of Southampton, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240612.
Full text
29
Foulkes, William Matthew Colwyn. "Interatomic forces in solids." Thesis, University of Cambridge, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328669.
Full text
30
Rayner, Anton. "Laser cooling of solids /." St. Lucia, Qld, 2002. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16448.pdf.
Full text
31
Hou, Hang-sheng. "Cavitation instability in solids." Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/13697.
Full text
32
Olusanmi, Oludolapo Janet. "Milling of organic solids." Thesis, University of Leeds, 2009. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.509852.
Full text
33
Chadwick, Alan V. "Diffusion in nanocrystalline solids." Diffusion fundamentals 2 (2005) 44, S. 1-22, 2005. https://ul.qucosa.de/id/qucosa%3A14377.
Full textAbstract:
Enhanced atomic migration was an early observation from experimental studies into nanocrystalline solids. This contribution presents an overview of the available diffusion data for simple metals and ionic materials in nanocrystalline form. It will be shown that
enhanced diffusion can be interpreted in terms of atomic transport along the interfaces, which are comparable to grain boundaries in coarse-grained analogues. However, the method of sample preparation is seen to play a major role in the experiments and there are still many gaps in understanding the detailed mechanisms of diffusion in these systems.
34
Llerar, Meza Gerónimo. "Upscaling nonreactive solute transport." Doctoral thesis, Universitat Politècnica de València, 2009. http://hdl.handle.net/10251/5848.
Full textAbstract:
This thesis focuses on solute transport upscaling. Upscaling of solute transport is usually required to obtain computationally efficient numerical models in many field applications such as, remediation of aquifers, environmental risk to groundwater resources or the design of underground repositories of nuclear waste. The non-Fickian behavior observed in the field, and manifested by peaked concentration profiles with pronounced tailing, has questioned the use of the classical advection-dispersion equation to simulate solute transport at field scale using numerical models with discretizations that cannot capture the field heterogeneity. In this context, we have investigated the use of the advection-dispersion equation with mass transfer as a tool for upscaling solute transport in a general numerical modeling framework.
Solute transport by groundwater is very much affected by the presence of high and low water velocity zones, where the contaminant can be channelized or stagnant. These contrasting water velocity zones disappear in the upscaled model as soon as the scale of discretization is larger that the size of these zones. We propose, for the modeling solute transport at large scales, a phenomenological model based on the concept of memory functions, which are used to represent the unresolved processes taking place within each homogenized block in the numerical models.
We propose a new method to estimate equivalent blocks, for which transport and mass transfer parameters have to be provided. The new upscaling technique consists in replacing each heterogeneous block by a homogeneous one in which the parameters associated to a memory functions are used to represent the unresolved mass exchange between highly mobile and less mobile zones occurring within the block. Flow upscaling is based on the Simple Laplacian with skin, whereas transport upscaling is based in the estimation of macrodispersion and mass transfer parameters as a result of the interpretation of the r<br>Llerar Meza, G. (2009). Upscaling nonreactive solute transport [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/5848<br>Palancia
35
Ottman, Michael J., and Stephen H. Husman. "Irrigation practices and Solum test weight and yield, 2002." College of Agriculture, University of Arizona (Tucson, AZ), 2002. http://hdl.handle.net/10150/203823.
Full textAbstract:
Solum is a barley adapted to one or two irrigations but the grain produced is often low in test weight. Studies were conducted on two commercial farms near Maricopa and Coolidge in an effort to verify data from previous studies suggesting that delaying the first post-emergence irrigation until boot increases test weight compared to earlier irrigation, but does not affect yield. The irrigation treatments consisted of 1) two irrigations – planting and boot, or 2) three irrigations – planting, 5- to 6-leaf stage, and heading (grower standard). The irrigation treatments had no effect on grain yield, test weight, kernel weight, or lodging at either location, but delaying the second irrigation until boot reduced plant height at Coolidge. Despite the lack of positive results from these studies, applying the second irrigation at boot may still be preferable to earlier applications because of reduced plant height and the risk of lodging. We have not been able to measure a benefit from a third irrigation for Solum barley in these or previous studies.
36
Meredith, Scott. "Extended techniques in Stanley Friedman's Solus for unaccompanied trumpet." Thesis, connect to online resource, 2008. http://digital.library.unt.edu/permalink/meta-dc-6075.
Full textAbstract:
Thesis (D.M.A.)--University of North Texas, 2008.<br>System requirements: Adobe Acrobat Reader. Accompanied by 4 recitals, recorded Apr. 12, 2004, June 3, 2004, June 14, 2005, and Mar. 10, 2008. Includes bibliographical references (p. 36-37).
37
Harrison, John. "Climatic variation, solute concentration and solute flux in meltwaters draining from an alpine glacier." Thesis, University of Salford, 2006. http://usir.salford.ac.uk/42976/.
Full textAbstract:
Cationic denudation rates in glacierised basins are considerably higher than the global mean. High specific discharge coupled with rapid dissolution of finely-divided sediment produced by glacial erosion results in high solute flux levels in rivers draining glacierised basins. As solute cc concentration varies inversely with discharge, variation with discharge of solute flux, the product of discharge and solute concentration, relates to the extent to which changes in volume of flow offset changes of concentration. Since the 1970s, in the European Alps, warming air temperatures have resulted in increases in discharge from glacierised catchments.
38
Klanner, Catharina. "Evaluation of descriptors for solids." [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=97123941X.
Full text
39
Martínez, García Julio César. "Dynamics in orientationally disordered solids." Doctoral thesis, Universitat Politècnica de Catalunya, 2011. http://hdl.handle.net/10803/35856.
Full textAbstract:
The key features of dynamics of ultraslowing glass forming systems are their universality in diversity. Its
origin is recognized as one of the greatest challenges of condensed matter physics and materials
engineering in the XXI century. Similar phenomena are observed on approaching the glass transition in
low molecular weight supercooled liquids, polymers, colloidal fluids as well as in solids, for instance in
orientationally disordered crystals, spin glass-like magnetic, vortex glasses. Pre-vitreous dynamics is also
proposed as a general reference for the category of complex liquids/soft matter systems.
The upsurge of the primary relaxation time or related dynamical properties is the basic physical
phenomena of the still mysterious previtreous behavior. This means a much more pronounced slowing
down than the Arrhenius pattern observed far above the glass transition temperature. Portraying this
behavior constitutes one of key checkpoints for theoretical models developed to unwind the glass
transition puzzle. However, none of the aforementioned features can answer the understanding that
governs the increase of relaxation time in liquids upon cooling.
In this thesis we focus on the above questions studying the dynamics of some materials for which their
molecules can retain a translational order being orientationally disordered between them upon cooling,
which are referred to plastic phases or orientationally disordered (OD) crystalline phases. The work
presented in this thesis potentially extends the knowledge of dynamics of OD phases and orientationally
glasses (OG), a research topic which has gained interest during the last decades.
Through this study, especial attention has been devoted to the phenomenological equations accounting
to the temperature dependence of the mean relaxation time describing the orientational dynamics .The
study was carried out by the use of BDS as well as two complementary experimental techniques. We
show distortion-sensitive and derivative-based empirical analysis of the validity of leading equations for
portraying the previtreous evolution of primary relaxation time. A new method for studying the dynamics of
glass forming systems is introduced and the minimization procedure is validated and discussed.
We present the results divided in two topics, the dynamics of the pure compounds and mixed crystals and
the derivative analysis through different existing models.
In the first topic we focus on the dynamics of the pure compounds and mixed crystals formed between
cycloheptanol and cyclooctanol as well as the a-relaxation dynamics of 1-cyano-adamantane and its
mixtures with 1-chloro-adamantane. The second topic is divided in two groups of models, linearized and
non-linearized models. In the linearized models we show the application of the derivative based,
distortion-sensitive analysis to liquid crystals (LC) and OD phases. We also discuss the results concerning
to the cases of the olygomeric liquid epoxy resin (EPON828), neopentylalcohol and neopentylglycol
mixture, isooctylcyanobiphenyl and propylene carbonate. The possible empirical correlations between one
of the linearized models with the universal pattern for the high frequency wing of the loss curve for primary
relaxation time for LCs and OD phases is also shown.
In the final part we show that the form of the equation recently introduced by Mauro et al. does not allow a
similar straightforward linearization procedure. Unlike the previous models, the involved parameters are
not correlated with the slope and the intercept of a linear function. In order to solve this problem, we have
introduced the concept of the enthalpy space.
The evidences of the existence of crossovers as well as quantitative descriptions are discussed. We show
also a new procedure for detecting the crossover in a very easy way. A new kind of crossovers which
seems to be impossible to be detected by the classical Stickel transformation is presented.<br>La principal característica de la dinámica de sistemas vítreos viscosos, es su universalidad en la
diversidad. Su origen es uno de los mayores desafíos de la física de la materia condensada y de la
ingeniería de materiales en el siglo XXI. La fenomenología típica de las fases vítreas se observan cerca de
la transición vítrea en líquidos subenfriados de bajo peso molecular, polímeros, fluidos coloidales, así
como en los sólidos con fases orientacionalmente desordenadas. La imposibilidad de explicar las causas
del gran aumento del tiempo de relajación al enfriar un líquido, constituye uno de los problemas más
importantes no resueltos en materia condensada. Con el objetivo de dar respuesta a dicha interrogante, se
han propuesto modelos termodinámicos y dinámicos que han resultado inconsistentes.
En esta tesis nos centramos en dicha problemática, estudiando la dinámica orientacional de algunos
materiales que al ser enfriados pueden conservar un orden traslacional mientras que se conserva el
desorden orientacional de las moléculas que los forman. Dichas fases se conocen como fases plásticas u
orientacionalmente desordenadas (OD).
El trabajo presentado en esta tesis amplía el conocimiento de la dinámica de dichas fases, un tema de
investigación cuyo interés ha aumentado durante las últimas décadas.
Se ha dedicado una atención especial a las ecuaciones fenomenológicas que describen la dependencia del
tiempo de relajación con la temperatura. El estudio se ha llevado a cabo mediante el uso de espectroscopía
dieléctrica de banda ancha, así como mediante el uso de técnicas experimentales complementarias. Se ha
introducido un nuevo método para el estudio de la dinámica de los sistemas que dan lugar a fases vítreas.
El método ha sido validado y discutido.
Los resultados de esta tesis se presentan divididos en dos temas, por un lado, la dinámica de compuestos
puros y de los cristales mixtos y, por otro, el análisis mediante el método derivativo aplicado a los
diferentes modelos físicos existentes. En el primer tema nos centramos en la dinámica de los compuestos
puros y los cristales mixtos formados por cicloheptanol y ciclooctanol, así como la dinámica de la
relajación alfa en 1-ciano-adamantano y sus mezclas con 1-cloro-adamantano. El segundo tema se divide
en dos grupos de modelos, los modelos lineales y no lineales. En los modelos lineales se muestra la
aplicación del procedimiento de derivativo en los cristales líquidos (CL) y las fases OD. También se
discuten los resultados relativos a los casos de la resina líquida (EPON828), la mezcla neopentil-alcohol y
neopentil-glicol, el carbonato de propileno, así como el CL isooctilcianobifenil. Se discute también la
existencia de posibles correlaciones empíricas entre uno de los modelos lineales con el patrón universal
para la parte de alta frecuencia de la curva de pérdidas dieléctricas de la relajación primaria para las fases
CL y OD.
En la parte final se muestra que la forma de la ecuación introducida recientemente por Mauro et al. no
permite la linearización mediante el método derivativo. A diferencia de los modelos anteriores, los
diferentes parámetros no están correlacionados con la pendiente y el origen de coordenadas de una función
lineal. Para resolver este problema, hemos introducido el concepto del espacio entálpico.
Se analiza también la existencia de cambios de comportamiento dinámicos y se aportan descripciones
cuantitativas. Se muestra también un nuevo procedimiento para detectar los cambios dinámicos de una
manera fácil, que permite incluso detectar aquéllos que son obviados mediante el método clásico de
Stickel.
40
Mostoufi, Navid. "Solids behaviour in fluidized beds." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0017/NQ53540.pdf.
Full text
41
Tekoğlu, Cihan. "Size effects in cellular solids." [S.l. : [Groningen : s.n.] ; University Library Groningen] [Host], 2006. http://irs.ub.rug.nl/ppn/298794977.
Full text
42
Fagas, Georgios. "Vibrational properties of complex solids." Thesis, Lancaster University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321898.
Full text
43
Broomfield, Seth Emlyn. "Picosecond optical studies of solids." Thesis, University of Oxford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.253303.
Full text
44
Ruiz-Diaz, J. E. "Fast ion transport in solids." Thesis, University of Oxford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355773.
Full text
45
Tronconi, Alvaro Luiz. "Magnetic resonance in crystalline solids." Thesis, University of Oxford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329981.
Full text
46
Clark, Robert Andrew. "Studies on novel molecular solids." Thesis, Bangor University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.252653.
Full text
47
Wilkes, Philip John. "NMR of phosphorus-containing solids." Thesis, Durham University, 1987. http://etheses.dur.ac.uk/6666/.
Full textAbstract:
The purpose of this work has been the determination of structure in solids using the technique of solid-state nuclear magnetic resonance spectroscopy. High-resolution (^31) p NMR spectra have been obtained for a range of phosphate species. A number of techniques have been applied to these systems including cross-polarization, magic angle spinning, and high power proton decoupling. Characterisation using additional NMR techniques such as (^1) H cramps has been carried out wherever possible. The results obtained yield molecular and crystallographic information consistent with data from X-ray diffraction when known. Shielding tensor components were determined from static and/or spinning spectra wherever possible. The phosphate species studied include a series of precipitated calcium phosphates. A particular model for the structure of amorphous calcium phosphate is favoured in the light of (^31) p NMR measurements. One sample showed NMR evidence for changes in composition whilst in the solid state. The origins of (^31) p NMR line widths in high-resolution solid-state spectra have been considered in some detail. Variation of (^31) p NMR linewidth as function of spinning rate has been noted for a number phosphate compounds. Multiple pulse techniques have been applied on the phosphorus channel with pleasing improvements in spectral resolution. Five solid binary phosphorus sulphides have also been studied using phosphorus MAS NMR, and the results compared to solution state data wherever possible. A number of anomalies between solution and solid-state data have been noted and discussed.
48
Quesada, Cabrera R. "Molecular solids at high pressure." Thesis, University College London (University of London), 2009. http://discovery.ucl.ac.uk/18772/.
Full textAbstract:
High pressure science has extended its applications beyond its classic domain of physics and geophysics. Diamond anvil cell techniques have been adapted to the study on chemical transformations at high pressure and pressure-modified reaction kinetics, contributing to a better understanding of reaction processes and new preparative strategies and opening unexplored chemical pathways for new materials. In this thesis, we aim to present examples of the contribution of the diamond anvil cell to high pressure science, as well as to explore potential applications for this revolutionary perturbation tool. We first introduce a study on sodium silicide (NaSi), a Zintl phase, a potential compound for polymerization at high pressure. This system is an interesting model that illustrates some of the common processes observed in high pressure research. The investigation on the behaviour of sodium orthonitrate (Na3NO4) at high pressure aimed to analyse possible routes towards the synthesis of as yet unknown orthocarbonates and maybe discover compounds with an ever higher coordination for nitrogen or a NO4-containing three-dimensional network. Recently synthesised polyoxometalate (POM) clusters have shown interesting thermochromic properties, which has been related to a redox reaction occurring within the metal-oxygen cage. At high temperature, it has been proposed that the SO3 heteroanion groups contained in the cluster transform to SO4 by the introduction of bridging oxygen from the cage. An oxygen rearrangement would reduce up to four metal atoms, inducing the colour change. We aimed to investigate here whether a similar electron localization process is possible upon compression of these systems. Finally, we develop pioneering high-pressure DAC experiments on amyloid fibrils, using synchrotron X-ray diffraction. Our approach allows us to estimate the Young’s modulus of these biological macromolecular materials and discuss their low compressibility for applications in nanotechnology.
49
McBride, Hugh Joseph. "Wave propagation in elastic solids." Thesis, Monterey, California. Naval Postgraduate School, 1992. http://hdl.handle.net/10945/24107.
Full text
50
Zhang, Zhichao. "Impact attrition of particulate solids." Thesis, University of Surrey, 1994. http://epubs.surrey.ac.uk/2945/.
Full text