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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
311

Ion selectivity in carrier-mediated dialysis and electrodialysis

Hansen, Steven Paul 02 May 2012 (has links)
Membrane transport processes underlie many purification technologies. The efficiency of a membrane separation process depends upon material throughput (flux), and the degree to which the membrane discriminates amongst species in the feed stock (selectivity). In a supported liquid membrane, flux may be enhanced by carrier molecules, which act as catalysts of translocation. Carrier molecules also confer selectivity, via differential molecular recognition of the substances in the feed stock. The effect of electrical potential on the flux and selectivity of carrier-containing supported liquid membranes is not well documented. We elected to study the effect of electrical potential on supported liquid membranes containing valinomycin, a potassium ionophore, and a calixarene ester, a sodium ionophore. In these systems, the open circuit membrane potential could be made positive or negative by the choice of anion. With both of these carriers, we observed that selectivity for potassium or sodium salts was dependent on the open circuit membrane potential. To confirm that electrical potential was responsible for the observed selectivity variance, we applied a potential across the membrane using a potentiostat. The applied potential created conditions for carrier-mediated electrodialysis, where oxidation and reduction reactions on either side of the membrane act as the driving force for transmembrane flux of charged species. In chronoamperometry experiments, we found that selectivity for potassium or sodium ion was dependent on the applied electrical potential. Subject to some constraints, selectivity and flux could be controlled by the application of positive or negative electrical potentials. Linear sweep voltammetry experiments allowed for the rapid prediction of the potential that must be applied to achieve optimal selectivity. We also found that membrane potential measurements, as well as the magnitude of current that flows in chronoamperometry experiments, could be interpreted to predict Eisenman and Hofmeister sequences. These results are novel, and await a convincing theoretical justification. The results also suggest that a separation technology could be developed around the idea of modulating selectivity with electrical potential. In this regard, carrier-mediated electrodialysis may be suitable for the sequestration of toxic or radioactive heavy metals, and a large number of carrier molecules for metal ions are currently known. The technique may also be suitable for separating organic molecules, such as high-value chiral pharmaceuticals. Supported liquid membranes are a useful research tool, but industrial applications may require a more stable membrane architecture. / Graduate
312

Structural dynamics of the selectivity filter in HCN1 ion channel

Ahrari, Sajjad 05 1900 (has links)
Les canaux HCN (cycliques nucléotidiques) activés par hyperpolarisation appartiennent à la superfamille des canaux cationiques voltage-dépendants et sont responsables de la génération de courant drôle (If) dans les cellules cardiaques et neuronales. Malgré la similitude structurelle globale avec le potassium voltage-dépendant (Kv) et les canaux ioniques cycliques nucléotidiques (CNG), ils montrent un modèle de sélectivité distinctif pour les ions K+ et Na+. Plus précisément, leur perméabilité accrue aux ions Na+ est essentielle à son rôle dans la dépolarisation des membranes cellulaires. Ils sont également l'une des seules protéines connues à sélectionner entre les ions Na+ et Li+, faisant des HCN des canaux semi-sélectifs. Ici, nous étudions les propriétés de sélectivité uniques des canaux HCN à l'aide de simulations de dynamique moléculaire. Nos simulations suggèrent que le pore HCN1 est très flexible et dilaté par rapport aux canaux Kv et qu'il n'y a qu'un seul site de liaison ionique stable dans le filtre de sélectivité qui les distingue des canaux Kv et CNG. Nous observons également que la coordination et l'hydratation des ions diffèrent dans le filtre de sélectivité de HCN1 par rapport aux canaux Kv et CNG. De plus, la coordination des ions K+ par les groupes carbonyle du filtre de sélectivité est plus stable par rapport aux ions Na+ et Li+, ce qui peut expliquer les propriétés de sélectivité distinctes du canal. / Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels belong to the voltage-gated cation channel superfamily and are responsible for the generation of funny current (If) in cardiac and neuronal cells. Despite the overall structural similarity to voltage-gated potassium (Kv) and cyclic nucleotide-gated (CNG) ion channels, they show distinctive selectivity pattern for K+ and Na+ ions. Specifically, their increased permeability to Na+ ions is critical to its role in depolarizing cellular membranes. They are also one of the only known proteins to select between Na+ and Li+ ions, making HCNs semi-selective channels. Here we investigate the unique selectivity properties of HCN channels using molecular dynamics simulations. Our simulations suggest that the HCN1 pore is very flexible and dilatated compared to Kv channels and that there is only one stable ion binding site within the selectivity filter which discriminates them from both Kv and CNG channels. We also observe that ion co-ordination and hydration differ within the selectivity filter of HCN1 compared to Kv and CNG channels. Additionally, the co-ordination of K+ ions by the carbonyl groups of the selectivity filter is more stable compared to Na+ and Li+ ions, which may explain the channel's distinct selectivity properties.
313

Intergenerational Persistence and Ethnic Disparities in Education

Engzell, Per January 2016 (has links)
This thesis consists of four self-contained essays in the sociology of educational stratification. Study I draws on newly collected survey data to assess the biases that arise in estimating socioeconomic differences in achievement when relying on parent and student reported data on social background. The main finding is that student reports on parental occupation overcome both the problem of misreporting that plagues other data collected from children, and the equally damaging problem of selective nonresponse among parents. Conditional estimates of ethnic disparities are relatively unaffected by these issues. Study II deals with student survey reports on the number of books in the home. A prominent string of authors has favoured this variable as a social background proxy over parental occupation or education based on its strong associations with educational outcomes. The paper applies various methods to large-scale student assessment data to show that these associations rest not on higher reliability as commonly assumed, but rather on two types of endogeneity. Low achievers accumulate less books and are also prone to underestimate their number. Study III uses survey and register data to study immigrant parents' education and its associations with children's achievement in recent Swedish cohorts. Two aspects of parental education are distinguished: the absolute years of schooling and a relative place in the source country's educational distribution. Parents' absolute education turns out to predict children's test scores and grades, whereas relative education is a better predictor of their educational aspirations. The result is of some consequence for studies seeking to assess ethnic disparities net of observed parental characteristics. Study IV extends the positional approach of Study III to understand immigrants' self-perceived social status and income satisfaction in European countries. Those higher educated by origin country than host country standards make more dismal assessments of their current situation than do other immigrants in otherwise similar circumstances. This is attributed to a social contrast mechanism and argued to be of relevance in understanding longer-term patterns of social and economic integration, including educational decisions made by the second generation. / Avhandlingen består av fyra fristående studier som alla berör utbildning och social stratifiering. Studie I undersöker med nyinsamlade enkätdata hur sociala skillnader i skolprestation riskerar att felskattas med bakgrundsuppgifter inhämtade från föräldrar respektive elever. Den viktigaste slutsatsen är att elevuppgifter om föräldrars yrke undviker mycket av den felrapportering som behäftar andra elevsvar, liksom det utbredda problemet med selektivt bortfall bland föräldrar. Villkorliga skattningar av etniska skillnader är relativt opåverkade av dessa metodproblem. Studie II granskar elevers uppgifter om antalet böcker i hemmet. En betydande litteratur har förespråkat denna variabel som ett mått på klasstillhörighet framför föräldrars yrke eller utbildning på grundval av starka samband med elevers studieresultat. Uppsatsen tillämpar en rad metoder på data från en internationell kunskapsutvärdering och finner att sambandens styrka inte vilar på högre tillförlitlighet som tidigare förmodats, utan på endogenitetsproblem av två slag. Lågpresterande elever ackumulerar färre böcker och är dessutom benägna att underskatta deras antal. Studie III använder enkät- och registerdata för att belysa utlandsfödda föräldrars utbildning och dess samband med prestationer bland svenska skolbarn. Två aspekter av utbildningsbakgrund särskiljs: föräldrars utbildningsår samt deras relativa placering i ursprungslandets fördelning. Absolut utbildning visar sig predicera elevers testresultat och betyg, medan relativ utbildning är en bättre prediktor för barns aspirationer. Resultatet är av betydelse för studier av etniska skillnader där statistisk kontroll görs för observerbara föräldraegenskaper. Studie IV tillämpar den positionella ansatsen från Studie III för att förstå utlandsföddas självupplevda status och inkomsttillfredsställelse i europeiska länder. Migranter som är mer högutbildade med ursprungslandets mått mätt än värdlandets tenderar att ha en mer negativ bild av sin nuvarande situation än andra i objektivt liknande omständigheter. Detta kan förstås i termer av sociala referensramar och framhålls som relevant i tolkningen av långsiktiga sociala och ekonomiska integrationsmönster, inklusive de utbildningsval som efterföljande generationer gör. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 3: Manuscript. Paper 4: Manuscript.</p>
314

Exploring and exploiting selectivity in rhodium-catalysed hydroacylation reactions

Poingdestre, Sarah-Jane January 2012 (has links)
Chapter 1 is an overview of the key developments in rhodium-catalysed hydroacylation. The main focus of this chapter is the use of various chelation strategies for the stabilisation of key rhodium-acyl intermediates. In addition, the more recent emergence of regioselective hydroacylation processes has been highlighted. Chapter 2 discloses the branched-selective intermolecular hydroacylation of 1,3-dienes and S-chelating aldehydes to afford synthetically useful 1,5-dione products. The evaluation of a number of different phosphine ligands for this process identifies a correlation between ligand bite angle and reaction regioselectivity. Chapter 3 discusses the development of a linear-selective hydroacylation process for previously challenging alkyne substrates. This, in combination with a complementary branched-selective process, provides a ligand-controlled regioselectivity switch between the branched and linear pathways. Finally, Chapter 4 details efforts towards the development of multicomponent, tandem processes through exploitation of our synthetically useful branched hydroacylation adducts.
315

Développement de méthodologies de synthèse d’hydroxyméthyl furfural (HMF) à partir de biomasse lignocellulosique. / Development of methodologies for the synthesis of hydroxy methyl furfural (HMF) from lignocellulosic biomass.

Despax, Solenne 05 December 2013 (has links)
L'acide furan-2,5-dicarboxylique (FDCA) a été répertorié en 2010 comme l'une des 10 principales molécules bio sourcées, pouvant servir de blocs de construction moléculaire pour remplacer l'acide téréphtalique d'origine pétrochimique, dans la production des polyesters à base de végétal. Ce composé fait partie de la famille des furanes et est obtenu après déshydratation et oxydation de sucres. Une des voies de synthèse utilise un intermédiaire clé, le 5-hydroxyméthylfurfural (HMF). Cependant, il n'existe aujourd'hui aucune production industrielle du HMF, en raison de sa réactivité intrinsèque. La formation de ce composé représente ainsi une des étapes limitantes dans la production de FDCA. Dans ce contexte, nous avons envisagé de nouvelles stratégies de synthèse du HMF économiquement favorables et respectueuses de l'environnement. L'étude de la déshydratation des monosaccharides présents en abondance dans la biomasse lignocellulosique a tout d'abord été effectuée. Les voies de synthèse ont été choisies dans la perspective d'un possible dimensionnement industriel et les coûts de production ont été minimisés afin d'obtenir le HMF à un prix compétitif. Des cristaux de HMF d'une pureté suffisante, pour une application industrielle, ont ainsi été fournis à partir de D-fructose, après une synthèse dans le diméthylsulfoxide sans catalyseur et une extraction liquide-liquide du composé. Le recyclage des solvants organiques utilisés pour la synthèse et pour l'extraction représente un réel avantage du procédé. A partir de D-glucose, la synthèse en milieu organique en deux étapes, sans purification intermédiaire, mais avec seulement une filtration, fournit un sirop de HMF concentré. Le catalyseur utilisé pour l'étape d'isomérisation du D-glucose en D-fructose a été recyclé avec succès. La conversion directe de la cellulose en HMF, dans un milieu contenant un solvant organique, a ensuite été abordée. La stratégie mise en place s'inscrit dans une démarche d'éco-conception visant à obtenir le HMF à partir de biomasse lignocellulosique, sans traitement préalable. L'accessibilité de la cellulose par sa solubilisation dans le milieu réactionnel est le premier défi à relever pour sa conversion ultérieure. La combinaison d'un catalyseur chloré et d'un système composé d'un sel d'ammonium et d'un solvant organique a été efficace pour produire le HMF. Du point de vue de la chimie durable, ce procédé présente de réels avantages tels que l'utilisation de réactifs (sel d'ammonium et catalyseur) peu onéreux et une production de HMF à partir de matières premières renouvelables. L'adaptation de cette méthode à la biomasse lignocellulosique a fourni des rendements modestes mais encourageants pour la suite des travaux. / 2,5-Furan dicarboxylique acid (FDCA) was listed in 2010 as one of the top 10 bio sourced molecules which can serve as building blocks to replace the petrochemical terephthalic acid in the production of polyesters based-plant. This compound belongs to the family of furans and can be obtained after dehydration and oxidation of sugars. One way of synthesis uses a key intermediate, 5-hydroxymethylfurfural (HMF). However, there is currently no commercial production of HMF because of its intrinsic reactivity. The formation of this compound thus represents one of the limiting steps in the production of FDCA. In this context, we have explored new strategies for the synthesis of HMF which could be economically and environmentally favorable. The study of the dehydration of monosaccharides which are abundant in lignocellulosic biomass was first carried out. Synthetic routes have been selected in view of a possible industrial development and in order to reduce as possible as we can the cost of production to obtain the HMF at a competitive price. Crystals of HMF with sufficient purity for industrial applications has been supplied from D-fructose after a synthesis in dimethylsulfoxide without catalyst and after a liquid-liquid extraction. Recycling of organic solvents used for the synthesis and the extraction represents a real benefit for this process. From D-glucose, a synthesis in organic medium in two steps without purification but only filtration afforded a syrup of concentrated HMF. The catalyst used for the isomerization step of the D-glucose into D-fructose was successfully recycled. The direct conversion of cellulose into HMF in a medium composed of an organic solvent was then approached. The implemented strategy is part of an eco-design approach to get the HMF from lignocellulosic biomass, without pretreatment. Accessibility of cellulose by its dissolution in the reaction medium was the first challenge for subsequent conversion. The combination of a chloride catalyst and a system composed of an ammonium salt and an organic solvent was effective to produce HMF. From the view point of sustainable chemistry, this method gathers noticeable advantages such as use of cheap ammonium additive, cheap and naturally abundant metal and allows production of HMF from renewable raw materials. The adjustment method to the lignocellulosic biomass has provided modest but encouraging yields for further work.
316

O princípio da coculpabilidade no estado democrático de direito / The principle of coculpability in a democratic state.

Zanotello, Marina 28 May 2013 (has links)
Sob a égide de um Direito Penal garantista, calcado, sobretudo, no respeito aos princípios constitucionais, e com o fim de coadunar o mal da pena com o cerne de todo o sistema que é a máxima da dignidade da pessoa humana, novos temas emergem da realidade social, provocando reflexões no sentido de se atualizar o Direito e seus institutos com as necessidades de uma sociedade que está cada vez mais dinâmica em suas relações. Devido à amplitude e importância de seu conceito, a culpabilidade vem sendo objeto de estudo, afinal, de acordo com a sistemática adotada pelo Código Penal brasileiro, este instituto corresponde ao cerne da Teoria do Delito. A partir dos estudos sobre a culpabilidade, surge a teoria da coculpabilidade que, por sua abrangência conceitual, hoje se considera princípio de origem constitucional. A reflexão parte da gritante desigualdade socioeconômica que se vislumbra atualmente dentro do grupo social, a qual se reforça pela omissão do Estado na efetivação das políticas públicas que possibilitam o acesso dos cidadãos aos direitos sociais, e do fato incontroverso que o meio no qual a pessoa vive condiciona a formação de sua personalidade e, consequentemente, a eleição de seus comportamentos. Atrela-se a isso o caráter seletivo que o sistema penal assume quando se verifica na realidade fenomênica sua utilização equivocada como mecanismo corretor de problemas como a incapacidade estatal de cumprir os deveres constitucionais no que atine à concreção do bem comum. A coculpabilidade, então, coloca o Estado e a sociedade para dividirem a culpabilidade pelo crime com a pessoa do delinquente, uma vez que se constate no caso concreto que esta foi privada do acesso aos seus direitos fundamentais por negligência estatal; essa divisão de responsabilidade pelo delito se dá na limitação do direito de punir. O reconhecimento do princípio da coculpabilidade como vigente no Estado Democrático de Direito apresenta-se um tanto controverso ainda na jurisprudência e na doutrina penal brasileira. Tem por objeto a presente pesquisa analisar o alcance de referido princípio e sua aptidão de atenuar ou mesmo excluir a pena, situando-o na Teoria do Delito como mecanismo eficaz para a concreção do Direito Penal mínimo. / Under the aegis of a criminal garantista law, trampled, especially in respect to constitutional principles, and consistent with the end of the of the penalty with the evil core of the whole system which is the maximum of human dignity, new themes emerge from the social reality, causing reflections in order to update the law and its institutions to the needs of a society that is increasingly dynamic in their relationship. Due to the breadth and importance of its concept, culpability has been the object of study, after all, according to the system adopted by the Brazilian Penal Code; this corresponds to the core Theory of Crime institute. Based on the studies on the guilt arises the co culpability theory which in conceptual comprehensiveness, today it is considered a constitutional principle of origin. The reflection part of whopping socioeconomic inequality that can be seen today within the social group, which is reinforced by the omission of the state in the fulfillment of public policies that enable citizens\' access to social rights, and the incontrovertible fact that the way in which a person lives affects the formation of his personality and therefore the election of their behaviors. It attaches itself to the selective character the penal system assumes that when there is in fact phenomenalistic use as mistaken a mechanism broker problems such as the inability to meet the state constitutional duties concerning the concretion of the common good. The co culpability then puts the state and society sharing culpability by crime with the person of the delinquent, since it is found in this case was deprived of access to their fundamental rights by state neglect, this division of responsibility for the crime occurs on limiting the right of punishing. The recognition of the principle of co culpability as existing in a democratic state has become somewhat controversial even in Brazilian criminal jurisprudence and doctrine. Aims at the present research to analyze the scope of this principle and its capacity to mitigate or even delete the sentence, placing it on the Theory of Crime as an effective mechanism for the concretion of minimal Criminal Law.
317

Diversidade de crisopídeos (Neuroptera: Chrysopidae) em sistemas de manejo de pragas dos citros, suscetibilidade a inseticidas e predação de Diaphorina citri (Hemiptera: Liviidae) / Diversity of lacewings (Neuroptera: Chrysopidae) in citrus pest management systems, susceptibility to insecticides and predation of Diaphorina citri (Hemiptera: Liviidae)

Rugno, Gabriel Rodrigo 02 April 2019 (has links)
Os crisopídeos (Neuroptera: Chrysopidae) são predadores de pragas agrícola e importantes agentes de controle biológico de pragas da citricultura na América por ocorrerem naturalmente nos pomares. Utilizar as principais espécies como agente de controle da praga-chave, Diaphorina citri Kuwayama (Hemiptera: Liviidae), é um passo importante para reduzir a dependência dos inseticidas. O objetivo com esse trabalho foi: 1) estudar a diversidade de espécies de crisopídeos no sistema de manejo orgânico e convencional de pragas dos citros; 2) a suscetibilidade de suas populações aos principais inseticidas; 3) a toxicidade desses princípios ativos em diferentes formas de exposição e o efeito repelente; 4) estudar o desenvolvimento da espécie de crisopídeo mais abundante nos pomares de citros no Brasil e nos EUA alimentando-se exclusivamente de D. citri; 5) e a predação de D. citri pelos crisopídeos em condições laboratório e campo. Não houve diferença significativa na abundância e diversidade de crisopídeos entre o sistema de manejo orgânico e convencional. Mais de 60% dos indivíduos coletados nos pomares do estado de São Paulo, Brasil, foi Ceraeochrysa cincta (Schneider) (Neuroptera: Chrysopidae). Essa espécie também foi a mais tolerante aos inseticidas clorpirifós, imidacloprido e bifentrina, enquanto que, Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae) foi a mais sensível. Para Ceraeochrysa cubana (Hagen) (Neuroptera: Chrysopidae), espécie presente no Brasil e predominante nos pomares na Flórida, EUA, dimeotato foi mais nocivo na exposição residual ou residual + ingestão. Fenpropatrina foi mais letal na exposição residual + ingestão, em contrapartida, nessa forma de exposição, imidacloprido teve baixa toxicidade ao predador e foi inócuo nas exposições residual e ingestão. Fenpropatrina também teve efeito repelente sobre C. cubana. Esse predador desenvolveu-se alimentando de D. citri, sendo que, as larvas de primeiro ínstar predaram em média 15 ninfas em 24 h e no campo (pomar na Flórida, EUA) reduziu a população da praga. Esses resultados indicam o potencial dos crisopídeos para serem utilizados em programas de manejo integrado. / Lacewings (Neuroptera: Chrysopidae) are predators of agricultural pests and important for citrus orchards in America because they occur naturally in orchards. Using the main species as a key-pest control agent, Diaphorina citri Kuwayama (Hemiptera: Liviidae), is an important step in reducing dependence on chemical control. The objective with this thesis was to study: 1) the diversity of lacewing species in the organic and conventional management system of citrus pests; 2) the susceptibility of their populations to the main insecticides; 3) the toxicity of these active principles in different forms of exposure; 4) the development of the most abundant lacewing species in citrus orchards in Brazil and the USA, feeding exclusively on D. citri; 5) the predatory capacity and pest control under field conditions. There was no significant difference in the abundance and diversity of lacewings between the organic and conventional management system. More than 60% of the individuals collected in the orchards of the state of São Paulo, Brazil was Ceraeochrysa cincta (Schneider) (Neuroptera: Chrysopidae). This species was also the most tolerant to the chlorpyrifos, imidacloprid and bifenthrin insecticides, whereas, Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae) was the most sensitive. Ceraeochrysa cubana (Hagen) (Neuroptera: Chrysopidae), species present in Brazil and predominant in orchards in Florida, USA, presented greater sensitivity to dimethoate residue and dimethoate or fenpropathrin residual + ingestion, whereas imidacloprid presented low toxicity to the predator and was harmless in residual and ingestion exposures. Fenpropathrin also had a repellent effect on C. cubana. This predator developed feeding of D. citri and the first instar larvae preyed on average 15 nymphs in 24 h and in the field controlled the population of the pest. These results show the potential of lacewings to be used in integrated pest management programs.
318

Manejo de Cyperus rotundus L. em cana-de-açúcar no sistema de mudas pré-brotadas (MPB) / Management of Cyperus rotundus L. in pre-sprouted seedlings (PSS) of sugarcane system

Giraldeli, Ana Ligia 03 May 2019 (has links)
A cultura da cana-de-açúcar passou por diversas alterações no cenário de manejo de plantas daninhas. Mais recentemente o sistema de plantio de cana-de-açúcar foi diversificado, podendo ser realizado com mudas pré-brotadas (MPB). O manejo de plantas daninhas está em constante mudança, devido à alteração da flora infestante, entretanto, a espécie Cyperus rotundus L. se destaca por aparecer em todos os momentos, devido a dificuldade de controle. Assim, objetivou-se com este estudo: A) Determinar o PAI (Período Anterior à Interferência), o PCPI (Período Crítico de Prevenção à Interferência) e o PTPI (Período Total de Prevenção à Interferência) em cana-de-açúcar plantada por meio de MPB; B) Avaliar o controle químico de plantas daninhas em MPB, com herbicidas utilizados para o manejo de C. rotundus; C) Avaliar o crescimento inicial de MPB após a aplicação de herbicidas utilizados para o manejo de C. rotundus; D) Avaliar o controle e a viabilidade de tubérculos de C. rotundus sob aplicação de herbicidas. Para todos os experimentos foi utilizada a cultivar de cana-de-açúcar IACSP95-5000. Para a determinação dos períodos críticos foi conduzido experimento em campo, no delineamento em blocos ao acaso, com 14 tratamentos e três repetições. Os tratamentos foram compostos por sete períodos de convivência e por sete períodos de controle das plantas daninhas: 0 - 30, 0 - 60, 0 - 90, 0 - 120, 0 - 150, 0 - 210 e 0 - 240 dias após o plantio (DAP). Foram realizadas avaliações de altura, diâmetro, número de perfilhos, peso de dez colmos e produtividade. O experimento de controle foi realizado em campo, no delineamento em blocos ao acaso, com dez tratamentos e quatro repetições. Os tratamentos correspoderam a aplicação de sulfentrazone (800 g i.a. ha-1), diclosulam (193,17 g i.a. ha-1), imazapic (133 g i.a. ha-1) e imazapyr (500 g e.a. ha-1) em pré-plantio (um dia antes do plantio) e, halosulfuron (112,5 g i.a. ha-1), ethoxysulfuron (135 g i.a. ha-1), MSMA (1.975 g i.a. ha-1) e 2,4-D (1.340 g e.a. ha-1) em pós-plantio (30 DAP), além de dois tratamentos controle (com e sem capina). Foram realizadas avaliações de altura, diâmetro, número de perfilhos, controle, sintomas de injúria e produtividade. O experimento de crescimento inicial de MPB foi realizado em casa de vegetação, em delineamento inteiramente casualizado, com nove tratamentos e quatro repetições. Os tratamentos corresponderam aos herbicidas aplicados em pré-plantio: sulfentrazone (200; 400; 800; 1.600 e 3.200 g i.a. ha-1), diclosulam (48,3; 96,6; 193,17; 386,34 e 772,68 g i.a. ha-1), imazapic (33,25; 66,5; 133; 266 e 532 g i.a. ha-1) e imazapyr (125; 250; 500; 1.000 e 2.000 g e.a. ha-1) e, pós-plantio: ethoxysulfuron (33,75; 67,5; 135; 270 e 540 g i.a. ha-1), halosulfuron (28,125; 56,25; 112,5; 225 e 450 g i.a. ha-1), 2,4-D (335; 670; 1.340; 2.680 e 5.360 g e.a. ha-1) e MSMA (493,75; 987,5; 1.975; 3.950 e 7.900 g i.a. ha-1), mais um tratamento controle. Foram avaliados os sintomas de injúria, altura, diâmetro, número de perfilhos, clorofila A, B e total, área foliar, massa seca da parte aérea e de raízes. O experimento de viabilidade de tubérculos foi realizado em casa de vegetação em delineamento inteiramente casualizado, com nove tratamentos e quatro repetições. Os tratamentos foram compostos pelos herbicidas aplicados em pré-emergência: 9 sulfentrazone (800 g i.a. ha-1), diclosulam (193,17 g i.a. ha-1), imazapic (133 g i.a. ha-1) e imazapyr (500 g e.a. ha-1) e em pós-emergência: halosulfuron (112,5 g i.a. ha-1), ethoxysulfuron (135 g i.a. ha-1), MSMA (1.975 g i.a. ha-1) e 2,4-D (1.340 g e.a. ha-1), mais um tratamento controle. Foram avaliados controle e viabilidade de tubérculos. O PAI, PCPI e PTPI foram de 26,26 - 68 e 68 dias, respectivamente. Os herbicidas em pré-plantio proporcionaram os melhores controles até 60 DAP. Entretanto, o diclosulam, imazapic e imazapyr provocaram sintomas de injúria graves reduzindo a produtividade. Os herbicidas de pós-plantio propiciaram sintomas de injúria leves, entretanto no experimento de campo os tratamentos resultaram em queda de produtividade devido ao baixo controle das plantas daninhas. A maior redução na viabilidade de tubérculos foi observada para sulfentrazone, imazapic, halosulfuron, ethoxysulfuron e MSMA. Os herbicidas isolados não foram eficazes para garantir o controle das plantas daninhas até 68 DAP. O correto posicionamento dos herbicidas é necessário para evitar danos severos à cultura. / The sugarcane crop underwent several changes in the weed management scenario. Recently the sugarcane planting system was diversified, being able to be realized with pre-sprouted seedlings (PSS) of sugarcane. Weed management is constantly changing, due to the change in weed flora; however, Cyperus rotundus L. stands out because it appears at all times, due to the difficulty of control. The aim of this study was determine: A) the PPI (Period Prior to Interference), CPIP (Critical Period of Interference Prevention) and TPIP (Total Period of Interference Prevention) in sugarcane in the PSS system; B) Evaluate the chemical control of weeds in PSS with herbicides used for the management of C. rotundus; C) To evaluate the initial growth of PSS of sugarcane after the application of herbicides used for the management of C. rotundus; D) Evaluate the control and viability of C. rotundus tubers under herbicide treatment. For all experiments the sugarcane cultivars used was IACSP95-5000. To determine the critical periods, a field experiment was carried out in a randomized block design with fourteen treatments and three replications. The treatments were composed of seven coexistence periods and seven weed control periods: 0 - 30, 0 - 60, 0 - 90, 0 - 120, 0 - 150, 0 - 210 and 0 - 240 days after planting (DAP). Were evaluated height, diameter, number of tillers, weight of ten stalks and yield. Control experiment was carried out in the field too, in a randomized block design, with ten treatments and four replications. The treatments application corresponding to the herbicides sulfentrazone (800 g a.i. ha-1), diclosulam (193.17 g a.i. ha-1), imazapic (133 g a.i. ha-1) e imazapyr (500 g a.e. ha-1) in pre-planting (um dia antes do plantio) and, halosulfuron (112.5 g a.i. ha-1), ethoxysulfuron (135 g a.i. ha-1), MSMA (1,975 g a.i. ha-1) and 2,4-D (1,340 g a.e. ha-1) in post-planting (30 DAP), and two control treatments (with and without weeding). In the control experiment were evaluated height, diameter, number of tillers, control, symptoms of injury and yield. The experiment of initial growth of PSS was performed in greenhouse, in a completely randomized design, with nine treatments and four replications. The treatments corresponded to the herbicides applied in pre-planting: sulfentrazone (200; 400; 800; 1,600 and 3,200 g a.i. ha-1), diclosulam (48.3; 96.6; 193.17; 386.34 and 772.68 g a.i. ha-1), imazapic (33.25; 66.5; 133; 266 and 532 g a.i. ha-1) and imazapyr (125; 250; 500; 1,000 and 2,000 g a.e. ha-1) and post-planting: ethoxysulfuron (33.75; 67.5; 135; 270 and 540 g a.i. ha-1), halosulfuron (28.125; 56.25; 112.5; 225 and 450 g a.i. ha-1), 2,4-D (335; 670; 1,340; 2,680 and 5,360 g a.e. ha-1) e MSMA (493.75; 987.5; 1,975; 3,950 and 7,900 g a.i. ha-1), plus one control treatment. Were evaluated symptoms of injury, height, diameter, number of tillers, chlorophyll A, B and total, leaf area, shoots and roots dry mass. The C. rotundus tubers viability experiment was carried out in a greenhouse in a completely randomized design, with nine treatments and four replications. The treatments were composed by herbicides applied in pre- emergence: sulfentrazone (800 g a.i. ha-1), diclosulam (193.17 g a.i. ha-1), imazapic (133 g a.i. ha-1) and imazapyr (500 g a.e. ha-1), and post-emergence: halosulfuron (112.5 g a.i. ha-1), ethoxysulfuron (135 g a.i. ha-1), MSMA (1,975 g a.i. ha-1) e 2,4- 11 D (1,340 g a.e. ha-1), plus one control treatment. Were evaluated control and viability of tubers. The results showing that PPI, CPIP and TPIP were 26, 26 - 68 and 68 days, respectively. Pre-planting herbicides provided better controls up to 60 DAP, however, diclosulam, imazapic and imazapyr caused severe injury symptoms reducing yield. Post-planting herbicides were considered selective, however in the field experiment the treatments resulted in a decrease of yield due to low weed control. The lowest viability of tubers was caused by sulfentrazone, imazapic, halosulfuron, ethoxysulfuron and MSMA. The isolated herbicides were not effective to ensure control of weeds up to 68 DAP. The correct herbicides setting is necessary to avoid damage to the crop.
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Stratégie de modélisation et d’optimisation des performances de l’ultrafiltration pour le fractionnement d’hydrolysats protéiques / Modelling and optimization strategy of ultrafiltration performances for the fractionation of protein hydrolysates

Bodin, Alice 13 December 2016 (has links)
Les hydrolysats protéiques ont une haute valeur ajoutée pour des secteurs industriels variés, de par leurs propriétés nutritives, fonctionnelles et / ou nutraceutiques. Pour améliorer les propriétés des hydrolysats, l’ultrafiltration est utilisée. Cependant, le manque d’outils de modélisation lié à la complexité des mélanges est un verrou pour une mise en œuvre rationnelle du procédé. Ces travaux ont permis de valider une stratégie de prédiction basée sur des caractéristiques classiques des hydrolysats et un étalonnage expérimental de la membrane d’ultrafiltration. Cette méthode permet de prédire les rendements et enrichissements en fraction(s) ou peptide(s) cible(s), ainsi que la productivité du procédé. Le modèle global de prédiction de l’ultrafiltration obtenu est alors utilisé afin d’optimiser la mise en œuvre de ce procédé. La démarche d’optimisation consiste à maximiser l’enrichissement de fractions ou de peptides cibles en minimisant la consommation d’eau et la durée du procédé / Protein hydrolysates are high added value mixtures for various industrial areas, thanks to their nutritive, functional or nutraceutical properties. To enhance hydrolysates performances, fractionation processes such as ultrafiltration are used. However, the lack of tools to predict ultrafiltration performances is a major bottleneck for a rational implementation of the process. This research thesis work enables to validate a prediction strategy based on classical characteristics of hydrolysates and an experimental calibration of the membrane. Yields and enrichment factors in targeted peptides or fractions during ultrafiltration as well as the productivity of the process can be predicted. This global methodology of performances prediction is then used to optimize the implementation modes of ultrafiltration. The multiobjective optimization approach consists in maximizing the enrichment in targeted peptides or fractions while water consumption and / or process duration is minimized
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Sélectivité modale d'ondes ultrasonores dans des guides d'ondes de section finie à l'aide d'éléments piézoélectriques intégrés pour le SHM / Modal selectivity of ultrasonic waves in waveguides of finite cross-section using integrated piezoelectric elements for SHM

Serey, Valentin 18 December 2018 (has links)
Les systèmes SHM (Structural Health Monitoring) basés sur la propagation d’ondes ultrasonores guidées sont utilisés pour des structures de grandes dimensions, par exemple dans les secteurs de l’aéronautique ou du génie civil. Les ondes de Lamb ou SH sont généralement employées car elles se propagent sur de longues distances dans des structures planes tout en sondant l’épaisseur des pièces. Cependant, des modes moins conventionnels se propagent dans les guides d’ondes de section droite finie, tels que les barreaux, les rails ou les tuyaux. Le nombre de modes peut être très élevé dans ce type de guide, et il est important de bien sélectionner un mode particulier.Les méthodes actuelles de sélectivité modale, basées sur l’emploi de plusieurs émetteurs,considèrent habituellement des éléments PZT identiques (même sensibilité, même réponse en fréquence...) et ne prennent pas en compte les conditions réelles de montage et leurs éventuelles imperfections (couplage variable entre traducteurs, mauvais alignement, différence de réponse de l’électronique...). Ce travail présente une méthodologie générale pour la sélectivité modale dans des guides à section droite finie, à l’aide de plusieurs éléments piézoélectriques disposés à leur surface. Cette sélectivité est basée sur la mesure expérimentale préalable, à l’aide d’un vibromètre laser 3D, des amplitudes des modes générés par chaque élément excité individuellement.Une procédure d’optimisation permet d’inverser le problème afin de maximiser l’amplitude du mode désiré, alors obtenue en excitant simultanément tous les émetteurs. Le problème à inverser requiert la connaissance des courbes de dispersion ainsi que des déformées modales des modes,obtenues en utilisant la méthode SAFE 2D. La méthodologie est testée à travers des simulations numériques et des mesures expérimentales sur un barreau d’aluminium de section rectangulaire instrumenté avec huit éléments PZT à sa surface. L’efficacité de la méthode pour générer différents modes purs, mais aussi pour détecter et localiser des défauts calibrés, est démontrée sur le barreau d’aluminium. Son fort potentiel pour des applications de SHM de structures plus complexes est étudié, tels qu’un rail ou un assemblage collé de matériaux composites. / SHM systems (Structural Health Monitoring) based on ultrasonic guided waves propagation are used for large structures, e.g. in Aerospace or Civil Engineering. Lamb or SH waves are usually employed as they propagate over long distances in plate-like structures while probing the entire thickness. However less conventional modes propagate in wave guides with finite crosssection,such as bars, rails or pipes. The number of modes can be very high even at low frequencyin this type of guide, and it is important to carefully select a specific mode. Current methods for modal selectivity, based on the use of several emitters, usually consider identical PZT elements(same sensitivity, same frequency response, etc.) and do not account for real experimental conditions and possible differences (variable coupling between transducers, flawed alignment,variable electronic response, etc.). This work presents a global methodology for modal selectivity in waveguides with finite cross-section, using several piezoelectric elements attached to their surface. This selectivity is based on experimental measurements, with a 3D laser vibrometer,of the amplitudes of the modes generated by each emitter. An optimization process allows to inverse the problem in order to maximize the amplitude of the desired mode, then generated by exciting all the emitters at once. This process requires knowing dispersion curves as well as the displacements of the various modes, calculated with SAFE 2D method. The methodology is tested through numerical simulations and experiments on an aluminium rectangular bar instrumented with 8 PZT elements on top. The method efficiency to generate different pure modes,and to detect and locate calibrated defects, is demonstrated for the aluminium bar. Its potential for SHM application of more complex structures is studied, like a rail or an adhesively bonded composite structure.

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