The continued spread of Palmer amaranth (Amaranthus palmeri S. Wats.) throughout the southern and midwestern United States is a result of herbicide-resistant populations. Besides being the most troublesome weed specie in several agronomic crops, Palmer amaranth is also host to economically important pests such as tarnished plant bug (Lygus lineolaris Palisot de Beauvois). Pesticide application methodology that maximizes efficacy while reducing selection pressure is needed to combat herbicide-resistant Palmer amaranth. Pulse width modulation (PWM) sprayers are used for pesticide application with the goal of maintaining product efficacy while mitigating spray drift. Additionally, alternative off-season weed management practices such as flooding could be adopted to optimize soil seedbank depletion. Therefore, evaluation of spray droplet size and flooding period on Palmer amaranth control and seed germination was conducted. The objectives of this research were to: (1) evaluate the influence of spray droplet size on lactofen and acifluorfen efficacy on Palmer amaranth using a PWM sprayer, (2) develop prediction models to determine spray droplet size that provides the greatest level of Palmer amaranth control, (3) evaluate the impact of flooding period and seed burial depth on Palmer amaranth seed germination in different soil textures, and (4) analyze the impact of nitrogen fertilizer application rate on the attractiveness of Palmer amaranth to tarnished plant bug. Results show that spray droplet size does not affect lactofen efficacy on Palmer amaranth, thus, coarser spray droplets are recommended to increase spray drift mitigation efforts. In contrast, acifluorfen applied with 300 μm (medium) spray droplets provided the greatest Palmer amaranth control. Furthermore, prediction models indicated that greater model accuracy was obtained when adopting a location-specific weed management approach. Flooding periods of 3, 4, and 5 months reduced Palmer amaranth seed germination across burial depths and soil textures. Therefore, fall-winter flooding may be adopted as an effective practice for soil seedbank depletion. Results also demonstrated that nitrogen fertilizer application rate does not consistently impact Palmer amaranth attractiveness to tarnished plant bug.

Orientador: Carlos Gilberto Raetano / Banca: Ulisses Rocha Antuniassi / Banca: Cristina Gonçalves de Mendonça / Resumo: Este trabalho teve como objetivo avaliar o efeito de adjuvantes sobre algumas propriedades de soluções aquosas, como tamanho de gotas, tensão superficial dinâmica e ângulo de contato das gotas em diferentes superfícies, natural e artificial, bem como avaliar o efeito desses produtos sobre a deposição e a deriva utilizando como alvo três espécies de plantas daninhas (Euphorbia heterophylla, Ipomoea grandifolia e Brachiaria plantaginea). Seis formulações de adjuvantes (Antideriva®, Uno®, Pronto 3®, Li-700®, Supersil® e Silwet L-77®) foram avaliadas em soluções aquosas contendo a dose recomendada do produto comercial e o dobro dela. As avaliações de tamanho de gotas foram feitas com três diferentes pontas de pulverização (AXI 110 015, 110 02 e 110 03) por um equipamento a laser (Mastersizer, Malvern) na pressão de trabalho de 414 kPa. Os ângulos de contato formados pelas gotas em duas superfícies, uma hidrofílica (vidro) e outra hidrofóbica (óxido de alumínio), foram obtidos por análise de imagens capturadas por uma câmera digital. As avaliações de deposição e deriva das soluções aquosas associadas ou não aos adjuvantes e contendo o traçador azul brilhante (0,15% v/v), foram feitas sobre diferentes espécies vegetais, e com o auxílio de coletores laterais (placas de Petri). A quantificação do traçador foi por feita espectrofotometria. A tensão superficial dinâmica e o ângulo de contato formado sobre as superfícies adaxiais das folhas foram medidos por um tensiômetro. Em relação ao tamanho de gotas, o adjuvante Antideriva, com dobro da dose recomendada, foi o que apresentou os menores valores percentuais de volume de gotas com diâmetro menor que 100 µm e os maiores DMV, para todas as pontas em teste. As soluções que proporcionaram as maiores ...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The aim of this work is to evaluate the effect of adjuvants on droplet size, dynamic surface tension and contact angle formed by the water drops in different surfaces, as well as evaluating the adjuvants effect on the deposit and the spray drift using three species of plants (Euphorbia heterophylla, Ipomoea grandifolia e Brachiaria plantaginea). We studied six adjuvants formulations (Antideriva™, Uno™, Pronto 3™, Li- 700™, Supersil™ and Silwet L-77™) in water solution using the dosage recommended by the manufacturer and twice that dose. The droplet size of three different nozzles (AXI 110 015, 110 02 and 110 03), for a constant pressure of 414 kPa, were evaluated by a laser system. The contact angles of the drops in two surfaces (hydrophilic and hydrophobic) were obtained by the analysis of images captured by a digital camera. The evaluation of deposition and spray drift deposition of the solutions containing brilliant-blue dye (0.15 % v/v) were carried out in different plant species. The solutions were collected laterally using Petri dishes, and the brilliant-blue dye content quantified by absorption spectroscopy. The dynamic surface tension and the angle formed on the surfaces of the leaves were measured by a tensiometer. Regarding the droplet size, for all the nozzles tested the adjuvant Antideriva with twice the recommended dose presented the lowest percentage of spray volume in droplets with diameters smaller than 100µm, and highest VMD. The solutions that provided the highest reductions in the dynamic surface tension and the smallest contact angle were the ones with the adjuvants Silwet L-77 and Supersil for both appraised doses. The largest deposit average for I. grandifolia was obtained by using Uno with double of the dose; for B. ...(Complete abstract click electronic access below) / Mestre

Monitoring of emulsion properties is important in many applications, like in foods and pharmaceutical products, or in emulsion polymerization processes, since aged and broken emulsions perform worse and may affect product quality. In machining processes, special types of emulsions called metalworking fluids (MWF) are widely used, because of its combined characteristics of cooling and lubrication, increasing the productivity, enabling the use of higher cutting speeds, decreasing the amount of power consumed and increasing tool life. Even though emulsion quality monitoring is a key issue in manufacturing processes, traditional methods are far from accurate and generally fail in providing the tools for determining the optimal useful life of these emulsions, with high impact in costs. The present study is dedicated to the application of a spectroscopic sensor to monitor MWF emulsion destabilization, which is related to changes in its droplet size distribution. Rapeseed oil emulsions, artificially aged MWF and MWF in machining application were evaluated, using optical measurements and multivariate calibration by neural networks, for developing a new method for emulsion destabilization monitoring. The technique has shown good accuracy in rebuilding the droplet size distribution of emulsions for monomodal and bimodal distributions and different proportions of each droplet population, from the spectroscopic measurements, indicating the viability of this method for monitoring such emulsions. This study is part of a joint project between the University of São Paulo and the University of Bremen, within the BRAGECRIM program (Brazilian German Cooperative Research Initiative in Manufacturing) and is financially supported by FAPESP, CAPES, FINEP and CNPq (Brazil), and DFG (Germany). / Sem resumo em português.

O monitoramento de emulsões utilizadas na indústria metalmecânica compõe uma importante atividade para o controle da qualidade das peças trabalhadas, proporcionando também o aumento da vida útil de ferramentas e maquinários utilizados neste setor através da lubrificação e refrigeração da região de corte. Em grande parte dos casos, estas emulsões são preparadas pela diluição de um fluido de corte em meio aquoso, constituindo assim um conjunto de gotículas estabilizadas em um meio contínuo devido à presença de compostos emulsificantes, estando constantemente sujeitas a ciclos de aquecimento e resfriamento durante os processos de usinagem. Apesar do acompanhamento deste material ser realizado através de análises periódicas usuais, não há um método eficiente estabelecido para verificar sua qualidade em tempo real e em linha de processo. Neste contexto, torna-se possível aplicar técnicas relacionadas à espectroscopia UV-Vis para se obterem informações sobre a estabilidade destes sistemas, correlacionando intensidades de espalhamento de luz com as dimensões das gotas presentes no meio. Dessa forma, tornou-se possível o estudo da desestabilização térmica de emulsões de um fluido de corte comercial, a qual mostrou-se, através do acompanhamento do cálculo do expoente do comprimento de onda, dependente do tempo de exposição ao aquecimento e de sua temperatura média temporal, não sendo influenciada pela perda de meio contínuo por processos evaporativos ou sua posterior reposição. Também se verificou que parâmetros típicos do processo de preparo de emulsões, como a temperatura do meio dispersante e o tempo de repouso do fluido de corte sobre a superfície do mesmo, apresentam fundamental importância para a definição do tamanho médio de gota inicial destes sistemas, o que forneceu evidência da possibilidade de se relacionar a área sob espectros de extinção de luz com tamanhos médios de gota. / The monitoring of emulsions used in the metal-mechanical industry comprise an important activity to the quality control of the products manufectured, also providing an increase in the working life of the tools and machinery employed in this sector through the lubrication and refrigeration of the cutting zone. In the majority of cases, these emulsions are prepared diluting a metalworking fluid in an aqueous media, constituting a collection of particles stabilized by emulsifiers and undergoing heating and cooling cycles during metalworking processes. Currently, monitoring routines are based on regular analyses of samples taken from the process fluid, and an effective in-line method is not available to monitor emulsion quality in real time. In this context, it is possible to apply techniques related to UV-Vis spectrocopy in order to obtain information concerning the stability of those systems, correlating light scattering intensities to the droplet dimensions. In this study, it was possible to investigate the thermal destabilisation of a commercial metalworking fluid emulsion, which showed, through the evaluation of the wavelength exponent, to be dependant on the exposure time to heating and its time-averaged temperature. It was also noted that the loss of continuous phase by evaporation and its reposition do not affect the emulsion stability. Moreover, it was observed that important emulsion preparation parameters, such as continuous phase temperature and the time span between the addition of the metalworking fluid on the water surface and the stirring, have fundamental roles in defining the initial average droplet size, which made possible to correlate the area under the light extinction spectra with average droplet sizes.

O monitoramento de emulsões utilizadas na indústria metalmecânica compõe uma importante atividade para o controle da qualidade das peças trabalhadas, proporcionando também o aumento da vida útil de ferramentas e maquinários utilizados neste setor através da lubrificação e refrigeração da região de corte. Em grande parte dos casos, estas emulsões são preparadas pela diluição de um fluido de corte em meio aquoso, constituindo assim um conjunto de gotículas estabilizadas em um meio contínuo devido à presença de compostos emulsificantes, estando constantemente sujeitas a ciclos de aquecimento e resfriamento durante os processos de usinagem. Apesar do acompanhamento deste material ser realizado através de análises periódicas usuais, não há um método eficiente estabelecido para verificar sua qualidade em tempo real e em linha de processo. Neste contexto, torna-se possível aplicar técnicas relacionadas à espectroscopia UV-Vis para se obterem informações sobre a estabilidade destes sistemas, correlacionando intensidades de espalhamento de luz com as dimensões das gotas presentes no meio. Dessa forma, tornou-se possível o estudo da desestabilização térmica de emulsões de um fluido de corte comercial, a qual mostrou-se, através do acompanhamento do cálculo do expoente do comprimento de onda, dependente do tempo de exposição ao aquecimento e de sua temperatura média temporal, não sendo influenciada pela perda de meio contínuo por processos evaporativos ou sua posterior reposição. Também se verificou que parâmetros típicos do processo de preparo de emulsões, como a temperatura do meio dispersante e o tempo de repouso do fluido de corte sobre a superfície do mesmo, apresentam fundamental importância para a definição do tamanho médio de gota inicial destes sistemas, o que forneceu evidência da possibilidade de se relacionar a área sob espectros de extinção de luz com tamanhos médios de gota. / The monitoring of emulsions used in the metal-mechanical industry comprise an important activity to the quality control of the products manufectured, also providing an increase in the working life of the tools and machinery employed in this sector through the lubrication and refrigeration of the cutting zone. In the majority of cases, these emulsions are prepared diluting a metalworking fluid in an aqueous media, constituting a collection of particles stabilized by emulsifiers and undergoing heating and cooling cycles during metalworking processes. Currently, monitoring routines are based on regular analyses of samples taken from the process fluid, and an effective in-line method is not available to monitor emulsion quality in real time. In this context, it is possible to apply techniques related to UV-Vis spectrocopy in order to obtain information concerning the stability of those systems, correlating light scattering intensities to the droplet dimensions. In this study, it was possible to investigate the thermal destabilisation of a commercial metalworking fluid emulsion, which showed, through the evaluation of the wavelength exponent, to be dependant on the exposure time to heating and its time-averaged temperature. It was also noted that the loss of continuous phase by evaporation and its reposition do not affect the emulsion stability. Moreover, it was observed that important emulsion preparation parameters, such as continuous phase temperature and the time span between the addition of the metalworking fluid on the water surface and the stirring, have fundamental roles in defining the initial average droplet size, which made possible to correlate the area under the light extinction spectra with average droplet sizes.

Monitoring of emulsion properties is important in many applications, like in foods and pharmaceutical products, or in emulsion polymerization processes, since aged and broken emulsions perform worse and may affect product quality. In machining processes, special types of emulsions called metalworking fluids (MWF) are widely used, because of its combined characteristics of cooling and lubrication, increasing the productivity, enabling the use of higher cutting speeds, decreasing the amount of power consumed and increasing tool life. Even though emulsion quality monitoring is a key issue in manufacturing processes, traditional methods are far from accurate and generally fail in providing the tools for determining the optimal useful life of these emulsions, with high impact in costs. The present study is dedicated to the application of a spectroscopic sensor to monitor MWF emulsion destabilization, which is related to changes in its droplet size distribution. Rapeseed oil emulsions, artificially aged MWF and MWF in machining application were evaluated, using optical measurements and multivariate calibration by neural networks, for developing a new method for emulsion destabilization monitoring. The technique has shown good accuracy in rebuilding the droplet size distribution of emulsions for monomodal and bimodal distributions and different proportions of each droplet population, from the spectroscopic measurements, indicating the viability of this method for monitoring such emulsions. This study is part of a joint project between the University of São Paulo and the University of Bremen, within the BRAGECRIM program (Brazilian German Cooperative Research Initiative in Manufacturing) and is financially supported by FAPESP, CAPES, FINEP and CNPq (Brazil), and DFG (Germany). / Sem resumo em português.

No description available.

An der Spitze der Morbiditäts - und Mortalitätsstatistik steht weltweit das Metabolische Syndrom, bestehend aus androider Adipositas, pathologischer Glukosetoleranz, Dyslipidämie und arterieller Hypertonie, verbunden mit einer erhöhten Inzidenz atherosklerotischer Gefäßerkrankungen. Der Replikationsinitiator 1 (Repin1) wurde kürzlich als mögliches Kandidatengen für Adipositas sowie damit verbundene metabolische Funktionsstörungen in kongenen sowie subkongenen Rattenstämmen identifiziert. Ziel der Arbeit war es, den Einfluss von Repin1 auf den Fettzellstoffwechsel zu untersuchen. Hierfür wurde die Expression von Repin1 in 3T3– L1 Präadipozyten und differenzierten 3T3-L1 Adipozyten mittels siRNA Technologie stark vermindert, um so auf mögliche Funktionen des Proteins schließen zu können. Nachfolgend wurden Veränderungen des Zellstoffwechsels mittels Glukosetransport, Palmitataufnahme sowie Triglyceridgehalt der Adipozyten untersucht. Repin1 wird in der 3T3-L1 Zelllinie exprimiert und zeigt eine steigende Expression während der Adipogenese. Der Knockdown von Repin1 resultierte in kleineren Fettzellen mit geringerer basaler, jedoch verstärkter insulinstimulierter Glukoseaufnahme. Auch der Fettstoffwechsel zeigte sich alteriert: Neben einer reduzierten Palmitataufnahme war die Expression verschiedener Schlüsselgene der Fetttropfenfusion, des Glukose-sowie des Fetttransportes verändert. Fazit: Repin1 reguliert die Expression von Genen, die eine Rolle bei der Festlegung der Fettzellgröße und des basalen und Insulin-stimulierten Glukosetransports in Adipozyten spielen.

Droplet growth processes in a cumulus cloud, beginning from its inception at sub-micron scale up to drizzle drop size of few hundred microns, in an average duration of about half hour, has been a topic of intense research. In particular role of turbulence in aiding droplet growth in clouds has been of immense interest. Motivated by this question, we have performed experiments in which turbulent natural convection coupled with phase change is set up inside a tall vertical insulated tube, by heating water located at tube bottom and circulating cold air at tube top. The resulting moist turbulent natural convection flow in the tube is expected to be axially homogeneous. Mixing of air masses of differing temperature and moisture content leads to condensation of water vapor into droplets, on aerosols available inside the tube. We there-fore have droplets in a turbulent flow, in which phase change is coupled to turbulence dynamics, just as in clouds. We obtain a linear mean-temperature pro le in the tube away from its ends. Because there is net flux of water vapor through the tube, there is a weak mean axial flow, but which is small compared to turbulent velocity fluctuations. We have experimented with two setups, the major difference between them being that in one setup, called AC setup, tube is open to atmosphere at its top and hence has higher aerosol concentration inside the tube, while the other setup, called RINAC setup, is closed to atmosphere and due to presence of aerosol filters has lower aerosol concentration inside the tube. Also in the latter setup, cold air temperature at tube top can be reduced to sub-zero levels. In both setups, turbulence attains a stationary state and is characterized by Rayleigh number based on temperature gradient inside the tube away from its ends, which is 107. A significant result from our experiments is that in RINAC setup, we obtain a broadened droplet size distribution at mid-height of tube which includes a few droplets of size 36 m, which in real clouds marks the beginning of rapid growth of droplets due to collisions among them by virtue of their interaction with turbulence. This shows that for broadening of droplet size distribution, high turbulence levels prevalent in clouds is not strictly necessary. Second part of our study comprises two pieces of theoretical work. First, we deal with the problem of a large collector drop settling amidst a population of smaller droplets whose spatial distribution is homogeneous in the direction of fall. This problem is relevant to the last stage of droplet growth in clouds, when the droplets have grown large enough that they interact weakly with turbulence and begin to settle under gravity. We propose a new method to solve this problem in which collision process is treated as a discrete stochastic process, and reproduce Telford's solution in which collision is treated as a homogeneous Poisson process. We then show how our method may be easily generalized to non-Poisson collision process. Second, we propose a new method to detect droplet clusters in images. This method is based on nearest neighbor relationship between droplets and does not employ arbitrary numerical criteria. Also this method has desirable invariance properties, in particular under the operation of uniform scaling of all distances and addition/deletion of empty space in an image, which therefore renders the proposed method robust. This method has advantage in dealing with highly clustered distributions, where cluster properties vary over the image and therefore average of properties computed over the entire image could be misleading.

La dérive de pulvérisation peut être mesurée au champ ou en soufflerie. Paradoxalement, les tests au champ sont sujets à de grandes variations dues aux conditions atmosphériques mais peuvent être plus facilement réalisés contrairement aux tests en soufflerie. Ainsi les principaux modèles de dérive sont basés sur des mesures au champ alors que peu de modèles s’inspirent de mesures en soufflerie. L’objectif de ce travail a été de définir un ou des descripteurs de la dérive sur la base de l’analyse de courbes de dépôts obtenues dans la soufflerie d’IRSTEA Montpellier. Par rapport aux souffleries existantes, un protocole d’exposition de longue durée a été utilisé avec une forte densité d’échantillonnage. Un plan expérimental comprenant 99 modalités a été réalisé en tenant compte de différents types de buses (FF, AI, AI Twin jet), différente hauteurs de rampe de 40 à 80cm, différentes positions de la rampe (frontale, latérale et angles intermédiaires) et différentes vitesses de vent entre 2 et 7.5m s-1. Les résultats ont montré que le taux de dérive à 5m sous le vent (DR5) correspond au descripteur le plus robuste si l’on tient compte du large spectre de paramètres et de réglages. Des modèles de premier ordre ont été définis pour l’expression de l’effet de la vitesse du vent ainsi que de la hauteur de rampe selon le temps de vol des gouttes (ToF). Ainsi il est possible de comparer des résultats issus de conditions expérimentales différentes et de simuler l’effet de la vitesse du vent et la hauteur de la rampe pour un type donné de buse. Des mesures in situ de taille de gouttes ont confirmé la pertinence du temps de vol comme base de l’expression des résultats. / Spray drift might be measured either infield or in a wind tunnel through specific sampling strategies. Paradoxically field tests are subjected to a high variability due to the atmospheric conditions but can be more easily conducted in the absence of a wind tunnel. The result is that most of spray drift models are based on infield measurements. Conversely very few models were developed on the basis of wind tunnel measurements. The objective of this work was to define spray drift descriptors from the analysis of drift curves in IRSTEA wind tunnel. Compared to the majority of existing wind tunnels, a long duration exposure protocol was applied with a high sampling density. A large experimental plan of 99 modalities were conducted including nozzle types (FF, AI, AI Twin jet), boom heights from 40 to 80cm, boom positions (frontal, lateral, and intermediate angles) and wind velocities from 2 to 7.5ms-1. Results showed that the drift ratio at 5m (DR5) was the most robust drift indicator considering the wide range of parameters and operations conditions (wind velocity, boom height). First order models were drawn for the expression of the effect of the wind velocity and the boom height according to the droplet time of flight (ToF). As a result it was possible to compare data from different experimental conditions and to simulate the effect of the wind velocity and the boom height for a given type of nozzle. In situ droplet size measurements confirmed the relevance of the time of flight expression.