Made available in DSpace on 2014-06-11T19:25:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-07-28Bitstream added on 2014-06-13T19:52:54Z : No. of bitstreams: 1 dioliveira_jrg_me_jabo.pdf: 437443 bytes, checksum: 045c528df9d0f7f94b99c898b9daaea8 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Objetivou-se avaliar o espectro, a deposição e cobertura das gotas de pulverização em função de equipamentos, volumes de calda, adjuvantes e dosagem de inseticida na mortalidade de Pseudoplusia includens. No laboratório realizou-se uma aplicação sobre as lagartas com os tratamentos: 2 equipamentos (bico rotativo e hidráulico) 2 volumes de calda (17 e 50 L ha-1 com o bico rotativo e 50 e 100 L ha-1 com o bico hidráulico), 2 dosagens do inseticida endosulfan (0,5 e 1,0 L pc ha-1), e 1 testemunha, seguindo o delineamento inteiramente casualizado. O experimento de campo foi realizado na fazenda da UNESP/Jaboticabal nas safras 2006/07 e 2007/08, em blocos casualizados com: 2 equipamentos (bico hidráulico e rotativo), 3 volumes de aplicação (50; 75; e 100 L ha-1 com o bico hidráulico e 17; 35; e 50 L ha-1 com o bico rotativo), aplicação com e sem adjuvante e 1 testemunha. Avaliou-se o número de lagartas vivas, a cobertura das gotas no papel hidrossensível, a deposição nas folhas de soja, e o espectro das gotas aspergidas utilizando um aparelho medidor de tamanho de partículas em tempo real do Laboratório de Análise do Tamanho de Partículas, do Departamento de Fitossanidade UNESP/Jaboticabal. Verificou-se que o volume de calda pode ser reduzido sem prejudicar o controle de P. includens, a dosagem de 0,5 L pc ha-1 não controla a lagarta-falsa-medideira em laboratório. Em campo, a melhor cobertura, deposição e mortalidade das lagartas foram alcançadas utilizando-se volume de 75 L ha-1 com o bico TT 11001, com a adição de adjuvante. O bico rotativo produz gotas de maior uniformidade e menor porcentagem de gotas suscetíveis à deriva, em relação ao bico hidráulico. A adição de adjuvantes promove gotas de maior tamanho e menos suscetíveis á deriva. / The aim of this work was to evaluate the spectrum, the deposition and coverage of droplets of spray due equipment, spray volumes, surfactans and dosage of insecticide in mortality of Pseudoplusia includens. The application in laboratory was done over the caterpillars with the tr~atments: 2 equipment (atomizer and hydraulic nozzles) 2 spray volumes (17 and 50 L ha-1 with the atomizer and 50 and 100 L ha-1 with the hydraulic nozzle), 2 doses of the insecticide endosulfan (0.5 and 1.0 L pc ha-1), and 1 untreated check, following the randomized plots. Was evaluated, the mortality of caterpillars, and the spectrum of droplets. The experiment was carried out in field with randomized blocks: 2 equipment (hydraulic nozzle and atomizer), 3 spray volumes (50, 75, and 100 L ha-1 with hydraulic nozzle and 17, 35 and 50 L ha-1 with atomizer), with and without adjuvant application and 1 untreated check. Was evaluated, the number of alive caterpillars, the coverage of droplets on sensitive paper, deposition on leaves of soybean, and the spectrum of droplets sprayed using in a particle size analyzer in real time. It was observed that spray volume in the laboratory can be reduced without harming the control of P. includens. The dos age of 0.5 L pc ha-1 does not controled satisfactorily the soybean looper caterpillar. On the field, the best coverage, deposition and controlled of caterpillar is achieved using a volume of 75 L ha-1 with hydraulic nozzle TI 11001, with addition of adjuvant. The atomizer produces droplets of more uniformity and less susceptibility to the percentage of droplets to drift, than hydraulic nozzle. The addition of adjuvants results in increase of droplets size and reducing susceptibility to drift.

Made available in DSpace on 2014-06-11T19:31:33Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-07Bitstream added on 2014-06-13T19:20:42Z : No. of bitstreams: 1 oliveira_rb_dr_botfca.pdf: 2430018 bytes, checksum: 83351333d3d9c8a67f6e396d9780730d (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / A alta demanda por agrotóxicos pelos sistemas de produção agrícola, aliada ao possível uso inadequado desses produtos, torna a deriva um dos maiores problemas potenciais da agricultura atual, e a escolha correta de adjuvantes pode ser uma das alternativas para minimizar os impactos negativos causados pela deriva nas pulverizações. Este trabalho foi desenvolvido com o objetivo de avaliar o efeito proporcionado por diferentes grupos de adjuvantes nas propriedades físicas e químicas das soluções, no espectro de gotas, bem como no potencial do risco de deriva quantificado em túnel de vento, como forma de auxiliar na escolha correta desses produtos para melhor utilização nas aplicações de agrotóxicos. Foram selecionados 18 adjuvantes comumente utilizados em misturas com agrotóxicos em pulverizações agrícolas, avaliando-se as propriedades físicas e químicas dos mesmos em soluções aquosas (viscosidade, densidade, tensão superficial e condutividade elétrica), o espectro de gotas e o potencial de deriva medido em túnel de vento. O experimento foi composto de 33 tratamentos, tendo a água como testemunha adicional, resultantes da diluição dos adjuvantes em diferentes concentrações, com três repetições. Para os ensaios em túnel de vento e análise de espectro de gotas foi utilizada uma ponta de pulverização XR8003 VK na pressão de 200 kPa, gerando um padrão de gotas médias. A deriva foi coletada no túnel de vento com fluxo de ar na velocidade de 2 m s-1. O corante Azul Brilhante a 0,6% (m v-1) foi utilizado como marcador para todas as soluções pulverizadas visando a quantificação da deriva por espectrofotometria. Os resultados mostraram que a adição de adjuvantes alterou as propriedades físicas e químicas das soluções aquosas em diferentes magnitudes, dependendo da concentração utilizada. Os surfatantes organosilicones... / Due to the high demand for pesticide by the agricultural systems and the possible inadequate use of the products, drift became one of the biggest concerns of the modern agriculture, and the correct use of adjuvants may be one of the possible alternatives to minimize the negative impact of spray operations. This study was developed to evaluate the effect of different adjuvants on physical and chemical properties of spray solutions, droplets spectra as well as drift potential measured in wind tunnel, aiming the correct choice of adjuvants to improve efficiency in pesticide application. For this purpose 18 commercially available agricultural spray adjuvants were selected including products usually mixed up with pesticides in the sprayer tank. The evaluation included physical and chemical properties of spray solutions (viscosity, density, surface tension and electric conductivity), droplets spectra and drift risk potential measured in wind tunnel. The experiment was set up with 33 treatments (solutions) obtained from 18 adjuvants used in different concentrations with 3 replications, including pure water as a standard. For wind tunnel tests and droplet spectra analysis it was used a Teejet XR8003 flat fan nozzles at 200 kPa (medium droplets) and all solutions were mixed up with a food color dye (Blue FDC) at 0,6% m v-1 for spectrophotometry analysis of drift deposits on the wind tunnel. The results showed that the addition of adjuvants changed physical and chemical properties of spray solutions in different magnitudes according to the product concentration. The organosilicon surfactants (Silwet 0.1% e 0.2% and BreakThru 0,1%) had the lowest values for surface tension, while the drift retardant based polymers (Define 0,06% e 0,12%) had the highest values for viscosity and density. There was high correlation between the Volume Median Diameter (VMD) and percentage of droplets smaller... (Completo abstract click electronic access below)

Made available in DSpace on 2014-06-11T19:24:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-07-18Bitstream added on 2014-06-13T18:20:53Z : No. of bitstreams: 1 chechetto_rg_me_botfca.pdf: 469390 bytes, checksum: 8e9fa1d749c62128208266d3bf55add5 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A importância da aplicação de agrotóxicos em cultivos agrícolas e a preocupação crescente com a segurança e a responsabilidade ambiental têm incentivado o desenvolvimento de novas tecnologias visando a redução do risco de deriva. Neste contexto, o objetivo deste trabalho foi estimar o potencial de deriva com diferentes pontas de pulverização e diferentes concentrações de adjuvantes. O ensaio foi instalado com seis caldas provenientes da diluição de diferentes tipos de adjuvantes a base de óleo vegetal, óleo mineral, surfactante e redutor de deriva, as quais foram aplicadas com duas pontas de pulverização, sendo uma de jato plano com pré-orifício (DG 8003 VS) e outra de jato plano com indução de ar (AI 8003 VS), totalizando 12 tratamentos com 3 repetições. O trabalho foi realizado em duas fases, sendo que na primeira o percentual de deriva foi analisado em condições controladas em túnel de vento e na segunda determinaram-se as características do espectro de gotas das pontas, utilizando-se um equipamento analisador de partículas em tempo real Mastersizer S (Malvern Instruments). As médias dos tratamentos foram comparadas pelo Intervalo de Confiança, ao nível de 95% de probabilidade e as correlações entre as variáveis foram analisadas utilizando o coeficiente de Pearson a 5% de probabilidade. A análise do espectro de gotas demonstrou diferentes comportamentos para cada tipo de adjuvante e ponta de pulverização. Para a porcentagem de deriva os tratamentos tiveram comportamento distinto, sendo o adjuvante a base de nonil fenol etoxilado o que apresentou maior interação, sendo a maior deriva com a ponta de pré-orifício e a menor deriva com a ponta com indução de ar. O comportamento dessas pontas foi inverso, para o potencial de deriva, quando o adjuvante a base de óleo foi utilizado / The importance of pesticide applications in crops and security and ambient responsibility concern has encouraged new techniques development aiming drift reduction. In this context, the objective of this work was estimate drift potential using different spray nozzles and adjuvants concentrations. The experiment was installed containing six solutions from different type adjuvant dilution, as vegetal oil, mineral oil, surfactant and drift reduction, which were applied with two nozzle, one pre-orifice flat fan (DG 8003 VS) and other of air induction flat fan (AI 8003 VS), resulting in 12 treatments with 3 replications each. The experiment was realized in two steps. In the first step, the drift percentage was analyzed in controlled conditions in wind tunnel and the second one determined droplet spectra characteristics, using a real time particle analyzer Mastersizer S (Malvern Instruments). The treatments averages were compared using Confidence Interval at 5% probability and the correlations between variables were analyzed using Pearson at 5% of probability. The analysis of droplet spectrum showed different behavior for each adjuvant and nozzle. Looking at drift percentage the treatments had different behavior and the nonil phenol ethoxylate adjuvant showed greatest influence with the highest drift for pre-orifice nozzle and the lowest for air induction nozzle. The nozzles behaviors were opposite for drift percentage when an oil-base adjuvant was used

Orientador: Ulisses Rocha Antuniassi / Banca: Marco Antonio Gandolfo / Banca: Paulo Roberto Arbex Silva / Resumo: A importância da aplicação de agrotóxicos em cultivos agrícolas e a preocupação crescente com a segurança e a responsabilidade ambiental têm incentivado o desenvolvimento de novas tecnologias visando a redução do risco de deriva. Neste contexto, o objetivo deste trabalho foi estimar o potencial de deriva com diferentes pontas de pulverização e diferentes concentrações de adjuvantes. O ensaio foi instalado com seis caldas provenientes da diluição de diferentes tipos de adjuvantes a base de óleo vegetal, óleo mineral, surfactante e redutor de deriva, as quais foram aplicadas com duas pontas de pulverização, sendo uma de jato plano com pré-orifício (DG 8003 VS) e outra de jato plano com indução de ar (AI 8003 VS), totalizando 12 tratamentos com 3 repetições. O trabalho foi realizado em duas fases, sendo que na primeira o percentual de deriva foi analisado em condições controladas em túnel de vento e na segunda determinaram-se as características do espectro de gotas das pontas, utilizando-se um equipamento analisador de partículas em tempo real Mastersizer S (Malvern Instruments). As médias dos tratamentos foram comparadas pelo Intervalo de Confiança, ao nível de 95% de probabilidade e as correlações entre as variáveis foram analisadas utilizando o coeficiente de Pearson a 5% de probabilidade. A análise do espectro de gotas demonstrou diferentes comportamentos para cada tipo de adjuvante e ponta de pulverização. Para a porcentagem de deriva os tratamentos tiveram comportamento distinto, sendo o adjuvante a base de nonil fenol etoxilado o que apresentou maior interação, sendo a maior deriva com a ponta de pré-orifício e a menor deriva com a ponta com indução de ar. O comportamento dessas pontas foi inverso, para o potencial de deriva, quando o adjuvante a base de óleo foi utilizado / Abstract: The importance of pesticide applications in crops and security and ambient responsibility concern has encouraged new techniques development aiming drift reduction. In this context, the objective of this work was estimate drift potential using different spray nozzles and adjuvants concentrations. The experiment was installed containing six solutions from different type adjuvant dilution, as vegetal oil, mineral oil, surfactant and drift reduction, which were applied with two nozzle, one pre-orifice flat fan (DG 8003 VS) and other of air induction flat fan (AI 8003 VS), resulting in 12 treatments with 3 replications each. The experiment was realized in two steps. In the first step, the drift percentage was analyzed in controlled conditions in wind tunnel and the second one determined droplet spectra characteristics, using a real time particle analyzer Mastersizer S (Malvern Instruments). The treatments averages were compared using Confidence Interval at 5% probability and the correlations between variables were analyzed using Pearson at 5% of probability. The analysis of droplet spectrum showed different behavior for each adjuvant and nozzle. Looking at drift percentage the treatments had different behavior and the nonil phenol ethoxylate adjuvant showed greatest influence with the highest drift for pre-orifice nozzle and the lowest for air induction nozzle. The nozzles behaviors were opposite for drift percentage when an oil-base adjuvant was used / Mestre

Le cancer constitue un problème majeur de santé publique en France. La nécessité de disposer d’un test capable de détecter très précocement une tumeur, avant même qu’elle ne soit décelable par l’imagerie (et surtout avant les métastases) ne fait pas doute. Pour l’heure, la voie la plus prometteuse pour détecter la maladie demeure la mise au point des tests simples, fiables, rapides et hautement sensibles, reposant sur le dosage de marqueurs génétiques (des biomarqueurs). Nous avons développé une procédure non-invasive, innovante et au moins 1000 fois plus sensible que les méthodes actuelles (0,0005% de séquences mutées détectées parmi un excès de séquences non-mutées), pour le criblage des biomarqueurs spécifiques des cancers. Elle peut facilement être utilisée pour le diagnostic, le pronostique ou la prédiction des procédures de gestion clinique des patients souffrant du cancer colorectal et par après pour les patients souffrant d’autres types de cancer. Cette méthode est basée sur l’utilisation des millions de microgouttelettes en tant qu’autant de bioréacteurs indépendants. Apportant ainsi la possibilité d’analyse chaque molécule d’ADN indépendamment, elle permettra de détecter spécifiquement une minorité de séquences mutantes au sein d’une forte quantité de séquences non mutées et avec un débit important. Nous avons développé cette stratégie pour la détection des mutations de l’oncogène KRAS (responsables des non-réponses aux thérapies ciblées) et nous l’avons validé avec la détection de mutations KRAS dans les échantillons de plasma sanguin et de tumeur des patients atteints d’un cancer colorectal métastatique. Notre méthode trouvera son utilité non seulement dans le domaine du diagnostic précoce des cancers, mais aussi dans cas de la prédiction de la réponse aux traitements ciblés grâce à la détection de biomarqueurs spécifiques. / The aim of this work is to establish novel strategies for the highly sensitive screening of cancer biomarkers in biological samples.To achieve this goal, we developed droplet-based microfluidic dPCR technique. Using a limiting dilution, individual DNA molecules are encapsulated within monodisperse droplets of a water-in-oil emulsion created with a microfluidic device. Fluorescent TaqMan® probes targeting the screened cancer biomarkers allow the detection of mutations. We focused on the mutations in the human KRAS gene for the development of our test. This method is also transposable in a multiplexed format for the parallel detection of multiple mutations in clinical samples.The developed technique allowed the precise quantification of a mutated KRAS gene in the presence of a 200,000-fold excess of un-mutated KRAS genes and enabled the determination of mutant allelic specific imbalance (MASI) in several cancer cell-lines. We validated our technique by screening for KRAS mutations in the blood plasma and tumor samples from patients with metastatic colorectal cancer.

abstract: III-Nitride nanostructures have been an active area of research recently due to their ability to tune their optoelectronic properties. Thus far work has been done on InGaN quantum dots, nanowires, nanopillars, amongst other structures, but this research reports the creation of a new type of InGaN nanostructure, nanorings. Hexagonal InGaN nanorings were formed using Metal Organic Chemical Vapor Deposition through droplet epitaxy. The nanorings were thoroughly analyzed using x-ray diffraction, photoluminescence, electron microscopy, electron diffraction, and atomic force microscopy. Nanorings with high indium incorporation were achieved with indium content up to 50% that was then controlled using the growth time, temperature, In/Ga ratio and III/N ratio. The analysis showed that the nanoring shape is able to incorporate more indium than other nanostructures, due to the relaxing mechanism involved in the formation of the nanoring. The ideal conditions were determined to be growth of 30 second droplets with a growth time of 1 minute 30 seconds at 770 C to achieve the most well developed rings with the highest indium concentration. / Dissertation/Thesis / M.S. Materials Science and Engineering 2012

abstract: High Voltage Direct Current (HVDC) technology is being considered for several long distance point-to-point overhead transmission lines, because of their lower losses and higher transmission capability, when compared to AC systems. Insulators are used to support and isolate the conductors mechanically and electrically. Composite insulators are gaining popularity for both AC and DC lines, for the reasons of light weight and good performance under contaminated conditions. This research illustrates the electric potential and field computation on HVDC composite insulators by using the charge simulation method. The electric field is calculated under both dry and wet conditions. Under dry conditions, the field distributions along the insulators whose voltage levels range from 500 kV to 1200 kV are calculated and compared. The results indicate that the HVDC insulator produces higher electric field, when compared to AC insulator. Under wet conditions, a 500 kV insulator is modeled with discrete water droplets on the surface. In this case, the field distribution is affected by surface resistivity and separations between droplets. The corona effects on insulators are analyzed for both dry and wet conditions. Corona discharge is created, when electric field strength exceeds the threshold value. Corona and grading rings are placed near the end-fittings of the insulators to reduce occurrence of corona. The dimensions of these rings, specifically their radius, tube thickness and projection from end fittings are optimized. This will help the utilities design proper corona and grading rings to reduce the corona phenomena. / Dissertation/Thesis / M.S. Electrical Engineering 2013

Cell encapsulation is a promising concept in regenerative medicine and stem cell treatment of diseases. Cells encapsulated in hydrogels have shown to yield better therapeutic outcome over cells in suspension. Microfluidic platforms have facilitated the process of cell encapsulation through the controlled mixing of aqueous cell solution and hydrogel with an immiscible liquid to yield a monodispersed population of microcapsules at a high throughput. However, given that the microfluidic process of placing cells in microcapsules is completely random, yielded samples are often riddled with empty microcapsules, raising the need for a post-encapsulation purification step to sort empty microcapsules from cell-laden ones. Sorting of microcapsules can be achieved through several techniques, most desirable of which are electrokinetic such as dielectrophoresis (DEP) and electrophoresis (EP). The advantages of DEP and EP techniques are that they support label-free sorting and yield a high throughput. However to achieve true effective DEP or EP sorting, there is a need to understand how empty microcapsules react to these electrokinetic forces versus occupied microcapsules. This study developed microfluidic devices for characterising the electrokinetic effects on microcapsules using DEP and EP. Results of both characterization techniques showed notable differences in the response of empty microcapsules versus cell-laden ones, reinforcing their potentials for sorting. Furthermore, this study proposed designs for microcapsules sorting devices that leverage EP and DEP.

In this work, microfluidic and millifluidic droplets are utilized to study and control complex fluid behavior with high composition resolution. Different techniques are used on two length scales to create unique approaches towards the same goal of merging droplet-based experiments with classical colloidal characterization experiments. First, a microfluidic dehydrating droplet device is characterized and a procedure established by concentrating a phase separating organic-inorganic system on chip and using geometric calculations to determine composition. The device is then expanded to a more complex, particle-polymer system to investigate suspension stability and interparticle behavior. A model system containing silica particles and PEO polymer is found to transition from a bridging flocculation mechanism to polymer-coated particle jamming based on the mass ratio of polymer to particle. Lastly, a phase separating particle-polymer system consisting of polystyrene particles and hydroxyethyl cellulose is concentrated on-chip. Interparticle interactions are controlled by varying particle size, polymer size, and polymer type and the effects on phase behavior are examined. Droplet experiments are scaled-up to millifluidic droplets and concentration gradients are used to produce high composition resolution in place of time, used in the dehydrating microfluidic experiments. A novel, millifluidic containment device is created to study aggregation and sedimentation in droplets containing carbon black and OLOA surfactant suspended in dodecane. A slow increase in stabilization behavior is observed as opposed to the previously observed sharp “on-off” effect. The droplet production technique is then improved to achieve more complex composition paths and the device is expanded for a small angle neutron scattering (SANS) application. SANS is performed on flowing droplets with varying concentration to map interparticle interactions and phase behavior of complex particulate systems. Feasibility of device is demonstrated and preliminary model systems of silica particles and polymer, salt, and surfactant are analyzed and characterized.

The goal of this work is to quantify the key design parameters such as the load capacity, actuation force, positioning repeatability, and reliability for droplet-based electrowetting actuators. Due to the fact that surface tension dominates gravity at both the mesoscale and microscale, droplet-based actuators can provide adequate force in manipulation tasks at those scales. Electrowetting, which uses an electric field to modulate the apparent surface tension of the liquid-ambient, provides a method to actuate droplets, which in turn transports the object carried by the droplet. Most previous electrowetting actuation efforts have concentrated on manipulating droplets in a closed two-plate configuration. In these configurations, a voltage potential is applied between a series of electrodes. The droplets can merge, split, and mix with only a voltage input, and without any external machinery. While some mechanical actuation demonstrations have been done, limited studies have been performed to investigate the key actuation performance characteristics of droplet-based actuators carrying solid objects. Design criteria for using droplets to carry solid components are still not well defined. The first part of this work provides fundamental understanding of the forces in electrowetting-based droplet actuation. The actuation force during electrowetting was experimentally validated according to the governing relation (Young–Lippmann equation) on a custom-designed testing apparatus. The results from the experiments show that the electrowetting actuation force is independent of surface tension below saturation, but the peak force is proportional to surface tension. Higher surface/interfacial tension would increase the actuation force in the horizontal direction, as well as the speed of the actuator. The second part of the dissertation demonstrates two actuation configurations based on electrowetting. The first actuator uses a droplet to carry a solid object and can be actuated in discrete steps to function as a micro-stepping linear motor. By implementing a leaky dielectric coating, the droplet/substrate contact area acts as an electrical diode. By varying the duty cycle of a square waveform, a range of droplet/part equilibrium position combinations are established. The underlying actuation mechanism was investigated and the position versus duty cycle relation was shown to be symmetrical but non–linear around the center of the electrodes. In contrast to the conventional electrowetting control scheme, the proposed actuation method required no feedback control loop while achieving a repeatability of less than 0.8% of the droplet diameter. Positioning matched a theoretical model based on idealized electrical elements to within 2.5% of the droplet diameter. The second type of electrowetting actuation uses metal-semiconductor diodes (Schottky diodes) in place of electrochemical diodes. This configuration uses only one pair of electrodes to actuate the droplet over a large distance (5X or more the droplet diameter). While the actuation concept had been previously demonstrated, the reliability of the diodes were shown to be insufficient. The new diodes actuated without degradation under repeated actuation (2000 cycles). Comparing this to electrochemical diodes, a 50% reduction in actuation voltage was also accomplished by Schottky diodes. The measured maximum speed also increased from 32 mm/s (electrochemical diodes) to 240 mm/s (Schottky), a 7.5 fold improvement. The last part of this dissertation used numerical simulations to investigate the load bearing capability and the stiffness variation of droplet-based actuators. The vertical force and stiffness - which are the primary figure of merit in designing droplet-based actuators are quantified. Three types of loading conditions were analyzed using simulation software and a simple analytical equation is shown to provide a useful approximation of the droplet force and stiffness. The results were further used in various case studies to demonstrate the optimal design strategy when using an electrowetting driven droplet as a fluidic bearing.