Point-of-care testing brings diagnosis and treatment monitoring to the site of the patient. It heavily relies on biosensors, which leverage the interactions between a target biomarker and a bioreceptor, to deliver fast and accurate results. However, non-specific binding of molecules and microorganisms on the biointerface can interfere with biomarker-bioreceptor interactions and diminish a biosensor’s sensitivity, specificity, and stability. In turn, this can lead to false diagnoses and ineffective treatments. Omniphobic-lubricant infused (OLI) coatings exhibit slippery, self-cleaning characteristics that repel untargeted molecules and microorganisms to augment the biosensor’s performance. In this work, we investigate the proficiency of OLI coatings in two specific applications: dissolved oxygen sensing and DNA biosensing. First, in water quality monitoring, an OLI coating is applied to the selectively permeable membranes of a dissolved oxygen sensor. Over a three-week incubation period in an environment with accelerated bacterial growth, the coated membranes exhibit a 160% higher reproducibility (10% deviation in sensitivity) and lower biofilm formation (96° static contact angle) in comparison to unmodified membranes (26%, 32°). The second application is in DNA biosensing, where a novel OLI coating uses carbon dioxide plasma activation to embed oligonucleotide probes. It demonstrates an optimized balance of slippery repellency (76° static contact angle, 10° sliding angle) and biosensing functionality, 19% longer clotting times than conventional blocking conditions, and equal sensitivity to PLL-PEG when capturing target DNA in whole blood. Going forward, our research will continue to expand the use of OLI coatings in biosensing applications, particularly exploiting its antibiofouling and anticoagulative capabilities. / Thesis / Master of Applied Science (MASc) / Biosensors are an integral tool in delivering quick and accurate point-of-care diagnosis and treatment monitoring. However, their performance can be impeded by the non-specific binding of undesirable molecules and microorganisms on the sensing surface. Omniphobic lubricant-infused (OLI) coatings have been shown to suppress biofouling and blood clotting on surfaces through exceptional repellency. This thesis focuses on the implementation of OLI coatings in biosensing applications. It investigates the antibiofouling capacity of an OLI coating on a membrane for dissolved oxygen detection. Then, it discusses a novel coating with integrated DNA biosensing functionality for working directly with blood samples. The enclosed work demonstrates that the OLI coating empowers biosensors to deliver more effective point-of-care testing.

The suitability of the open, stirred-jar technique as a method to estimate oxygen-uptake due to degradation of organic waste and nitrification by suspended microbes was studied. With this procedure, both the concentration of waste and the reaeration rate can be set to values similar to those expected in the stream. Thus, the conditions in the jars resemble the deoxygenation process in the stream more closely than the BOD-bottle test. There is no need of assuming any particular type of kinetic behavior, because the procedure gives directly an oxygen-uptake curve. Long lags before nitrification were observed. In most experiments, the oxygen-uptake rate during the nitrification stage increased slowly, resembling a first-order increasing or autocatalytic behavior. When a waste with a low COD:TKN ratio was used, the oxygen-uptake rate was constant and low, resembling zero-order kinetics. The results showed that accurate estimates of oxygen-uptake can be obtained with the open stirred-jar test. The oxygen-uptake patterns include variations in the oxygen-uptake rate that are smoothed out when the classical BOD-bottle test and the first-order model are used. / M.S.

Riparian deforestation is a significant threat to freshwater riverine ecosystems and sensitive fauna that depend on clean water. Sensitive aquatic species are vulnerable to the destruction of riparian forest cover which diminishes protection from pollutants, sedimentation, and solar radiation, while also depleting dissolved oxygen. In this thesis, I explore the influence of degraded riparian forest cover and its effect on dissolved oxygen on the embryonic viability of a sensitive freshwater habitat specialist, the Eastern hellbender. Hellbenders are a large-bodied, long-lived amphibian that inhabits fast flowing, cold mountain streams in the eastern United States. Over the last several decades, hellbender populations have experienced declines that are associated with low riparian forest cover, a geriatric population age structure, and high rates of nest failure. Adult male hellbenders normally provide extensive paternal care to embryos and larvae over an 8-month period. However, researchers have recently discovered that in degraded populations, hellbender nests are failing due to whole-clutch filial cannibalism by adult males. The underlying mechanism that triggers males to eat their young remains unknown, but one possibility is that eggs are not developing properly and as a result the attending male ceases to provide care. However, the embryonic viability of clutches developing in habitats with low riparian forest cover is unknown. Given the limited research on hellbender embryonic viability, I first sought to examine whether embryo viability is associated with a forest cover gradient. To accomplish this, I inherited two years of laboratory and field data, and I conducted a final third year of data collection for the study. Over these three years of data collection, I simultaneously evaluated embryo viability in a controlled captive rearing system while classifying nest failure due to whole-clutch cannibalism of sibling embryos in the field. I found significantly lower hellbender embryo viability, faster hatching times, and higher rates of underdeveloped hatchlings in hellbender populations with degraded riparian forest cover. However, I found no relationship between embryonic viability and whole-clutch filial cannibalism. I concluded that elevated specific conductance of water (i.e., dissolved ions) associated with loss of forest cover may affect the embryonic development of hellbenders, but this hypothesis has yet to be tested. To further explore the impact of degraded riparian forest cover on hellbender embryonic viability, I designed a study to evaluate the influence of depleted dissolved oxygen on embryonic development. To accomplish this, I designed and implemented a dissolved oxygen manipulation system to rear sibling embryos in high, medium, and low dissolved oxygen concentrations. I found that hellbender embryos are vulnerable to relatively modest reductions in dissolved oxygen (i.e., 5 mg/L), comparable to those found to affect embryos of some of the most sensitive species examined to date. Nests reared in low dissolved oxygen had a lower percentage of viable hatchlings, lower hatching success, higher rates of underdeveloped hatchlings, and smaller morphometrics compared to those reared at higher dissolved oxygen concentrations. I concluded that hellbenders may be particularly susceptible to reductions in dissolved oxygen because of their high degree of specialization for well oxygenated streams, and I suggest prioritizing additional research on dissolved oxygen to advance hellbender conservation. Taken together, my research established a foundation of knowledge on the sensitivities of hellbender embryos to degraded water quality caused by low riparian forest cover. Further, my work underscored the importance of riparian forest conservation for hellbender populations and for other freshwater biodiversity. Protection of riparian forest will also be critical to build resilience in streams against the existential threat of climate change. / Master of Science / Deforestation along rivers is a significant threat to freshwater systems and sensitive animals that depend on clean water. Sensitive river species are vulnerable to the destruction of forest cover which removes protection from pollutants, run off, sun light, and exposes them to low dissolved oxygen—the amount of oxygen in the water, which is necessary for the survival of aquatic animals. In this thesis, I explore how low forest cover may impact egg quality of a sensitive freshwater animal, the eastern hellbender salamander. Hellbenders are a large-bodied, long-lived amphibian that lives in fast-moving, cold mountain streams in the eastern United States. Over the last several decades, hellbender numbers have rapidly declined. These declines are associated with low forest cover along streams, elderly populations, and unsuccessful nests. Adult male hellbenders normally provide care to their eggs and hatchlings for about eight months after the eggs are laid. Researchers have recently found that in streams where hellbender numbers are declining, hellbender nests are not successful because adult males are eating their eggs before the eggs can hatch. Researchers know that low forest cover triggers hellbender fathers to cannibalize their eggs, but the mechanism by which forest cover causes this trigger is unknown. Unsuccessful nests due to cannibalistic fathers in declining populations suggest that hellbender eggs might be unhealthy, making it more profitable to eat them than to care for them. However, the health of eggs in water from low forest cover is unknown and an important knowledge gap to fill to uncover what is triggering cannibalism in low forest cover populations. Given the limited research on hellbender egg health, I first sought to examine whether egg health is associated with changes in forest cover. To do this, I received two years of laboratory and field data, and I conducted a final third year of data collection for the project. Over these three years of data collection, I determined egg health by raising eggs in their own site water in the lab and simultaneously determined whether siblings in the field were eaten by their dads. I found lower hellbender egg health, shorter time to hatch, and more premature hatchlings in hellbender populations with low forest cover. However, I found no relationship between egg health and whether hellbender dads ate their eggs. I concluded that poor water quality associated with loss of forest cover may affect the health of hellbender eggs, but this has not been tested yet. To further explore the impact of low forest cover on hellbender egg health, I designed a study to determine the influence of low dissolved oxygen on egg health and growth. To do this, I designed and implemented a dissolved oxygen experiment to raise sibling eggs in high, medium, and low dissolved oxygen levels. I found that hellbender eggs are vulnerable to relatively moderate levels of reduced oxygen (i.e., 5 mg/l), which is comparable to how other highly sensitive species react. Nests raised in low dissolved oxygen had a lower number of healthy hatchlings, lower number of eggs that hatched, higher numbers of premature hatchlings, and smaller sizes compared to those raised in higher dissolved oxygen levels. I concluded that hellbenders may be particularly vulnerable to low dissolved oxygen because they have adapted to live in well oxygenated streams, and I emphasize the importance of studying dissolved oxygen to inform hellbender conservation. Taken together, my research created a foundation of knowledge on the vulnerabilities of hellbender eggs to poor water quality because of low forest cover. Filling these knowledge gaps is important, because it informs policy makers and managers on how to best protect hellbenders and other stream animals from declining. Further, my work emphasized the importance of forest conservation for hellbenders and for other sensitive freshwater animals. Forested streams will also be important to build protection against other human disturbances, such as climate change.

Dissolved oxygen at four times normal saturation inhibited growth and metabolism of summer planktobacteria in surface waters of alpine oligotrophic Mountain Lake (Giles County, Virginia). Data included viable colony counts, D-[U-¹⁴C]glucose incorporation into extractable lipid of colonies, and respiration-assimilation of D-[U-¹⁴C]glucose by lake water samples. Significant (P<0.05) differences were not detected in either colony counts or ¹⁴C-lipid when superoxide dismutase (30 U ml⁻¹) or catalase (130 U ml⁻¹) were added to the medium. The upper waters of Lake Hoare, Antarctica, contain dissolved oxygen at ≥42 mg liter⁻¹ (=HDO). HDO did inhibit D-[U-¹⁴C]glucose assimilation-respiration compared with normal atmospheric dissolved oxygen (=ADO) in Lake Hoare water. D-[U-¹⁴C]glucose was assimilated and respired optimally at 12°C in Lake Hoare. Colony formation was inhibited in both lakes. Colonies represented <1% of the fluorochrome-stained direct counts in Lake Hoare. Lake Hoare planktobacteria were smaller than the planktobacteria in Mountain Lake. ATP size fractionation revealed that 39% of ATP biomass was <0.5 Hm in Lake Hoare. Five microbial isolates were selected from Lake Hoare by growth under very high oxygen (=VHO, 4.6x in situ HDO, 55 lb in⁻² of added oxygen). One isolate was selected under ADO from shallow benthic mat underlying HDO waters. Isolates were examined for physiological characteristics which might enhance their survival in the HDO environment. While HDO incubation produced <36% of ADO incubated CFU, VHO was more selective producing <1%. Bacterial isolates were motile Gram negative rods, catalase and oxidase positive, differing in their growth response to temperature and nutrient concentration. One VHO isolate was a yeast. HDO reduced the maximal cell density in three isolates tested at higher nutrient concentrations, however, all three exhibited less repression as nutrients were lowered from 1000-10 mg liter⁻¹ in comparison to ADO grown controls. One isolate actually produced a cell density 3x that of the ADO control. Four of five bacterial isolates demonstrated HDO inducible superoxide dismutase (SOD). The inducible and constitutive SOD were the manganese type and had the same electrophoretic mobilities in respective isolates. All VHO isolates contained carotenoids. Pigmentation of the bacterial isolates differed due to the types and relative proportions of the constituent carotenoids. A carotenoid-negative mutant of one isolate grown under HDO exhibited a lengthened lag phase, decreased growth rate, maximal cell density and thereafter increased lysis compared to the same ADO grown strain and the carotenoid containing parent strain. The mutant and parent strain produced catalase and indistinguishable specific activities of SOD. Microorganisms in the high oxygen Lake Hoare waters may be protected from oxygen toxicity by the lake’s oligotrophic nature as well as a combination of cellular defenses. / Ph. D.

Le cycle du carbone est régi principalement par les phénomènes de production et de reminéralisation de la matière organique le long de la colonne d'eau. Les acteurs principaux de cette reminéralisation sont les procaryotes hétérotrophes, dont les actions peuvent être mesurées sur l'ensemble de la colonne d'eau via la respiration procaryotique. Au cours de ce travail de thèse, un suivi à long terme et en temps réel des conditions hydrologiques et biogéochimiques (température potentielle, salinité et oxygène dissous, O2) a été mené entre 2008 et 2010 en Méditerranée Nord Occidentale, sur le site ANTARES. Ces observations ont permis de mettre en évidence les influences d'évènements ponctuels (convection hivernale d'eau profonde) par advection sur ces paramètres hydrologiques et biogéochimiques. Ces influences, directes ou indirectes, vont également avoir des incidences sur la concentration en matière organique et donc sur le potentiel reminéralisateur du milieu profond. Le suivi temporel de la concentration d'O2 a également permis de mettre en évidence une diminution de la concentration globale de 2.6 µmol O2 dm-3 a-1, sur une période de trois ans. Le développement au sein du laboratoire et en collaboration avec le Centre de Physique des Particules de Marseille (CPPM) d'un nouvel outil en équipression, le IODA6000 (In situ Oxygen Dynamics Autosampler), mesurant directement et à haute fréquence la dynamique de l'O2 a permis d'obtenir des vitesses de respiration procaryotique à 2000 m de profondeur depuis décembre 2009 sur le site ANTARES. / The carbon cycle is mostly driven by production and remineralisation processes which are constraining organic matter concentration along the water column. The main actors of the remineralisation are the heterotrophic prokaryotes, which actions can be measured from surface to deep by the prokaryotic respiration. During this PhD thesis, a long term real time monitoring of hydrological and biogeochemical conditions (potential temperature, salinity and dissolved oxygen O2) has been carried out between 2008 and 2010 in the North Occidental Mediterranean Sea, at the ANTARES site. Influence of punctual events has been observed which seem to be related to winter deep sea convection and subsequent advection, changing hydrological and biogeochemical properties observed at the ANTARES site. These direct or indirect modifications will have consequences on the organic matter concentration and therefore on the deep-sea remineralisation potential. The temporal monitoring of O2 concentration has also allow us to estimate the deep water oxygen consumption of 2.6 µmol O2 dm-3 a-1, during a three year period. The development in our laboratory in collaboration with Centre de Physique des Particules de Marseille (CPPM) of a new equipressured tool, the IODA6000 (In situ Oxygen Dynamics Autosampler), measuring directly and at high frequency the O2 concentration, allowed us to measure PR rates at 2000 m depth since December 2009 at the ANTARES site. This unique ongoing time series shows a mean prokaryotic respiration rates higher (0.2 µmol O2 dm-3 d-1) than expected by literature (5.5 10-3 µmol O2 dm-3 d-1), with a high temporal variability (from 8 10-3 to 0.5 µmol O2 dm-3 d-1).

Gävle kommuns VA-huvudman Gästrike Vatten AB ansvarar för dricksvattenproduktionen i Gävle. För Gävles tätort tas vatten från Valboåsen som sträcker sig från öster om staden, genom staden och vidare norrut. Denna rapports syfte är att genom mätning av halten löst syre undersöka Valboåsens förbindelse till Gavleån. Detta kommer ge en ökad förståelse för åsens komplexitet. Resultatet kommer också att användas för att verifiera och utveckla den konceptuella modellen över flödena i åsens grundvattenmagasin som tagits fram av Midvatten AB. För att kunna mäta halten löst syre har en provtagning skett på grundvattenrör. I provtagningen ingick även så kallade slugtest där rörens kapacitet och anslutning till grundvattenmagasinet säkerställdes. Efter mätningen sammanställdes resultatet för att kunna jämföra halten löst syre i grundvattenrören mot den konceptuella modellen. Resultatet visade att halten löst syre i vattnet i de olika grundvattenrören stöder den konceptuella modellen till stora delar och gav även mer information om områden längs åsen där kunskap om flödesförhållandena tidigare var osäkra. Metoden i den utförda studien har visat stor användbarhet för att påvisa flödesförhållanden och ytvattenpåverkan i Valboåsen vilket visar att mätning av syrehalt kan vara mycket användbart i grundvattenutredningar angående ytvattenpåverkan. För att utöka studien av Valboåsen i framtiden behövs mer provtagning i grundvattenmagasinet på områden som inte ingick i denna studie. / Gävle municipality's water company is Gästrike Vatten AB. They manages the drinking water production for the City of Gävle. The production starts in the ridge of Valbo which extends between Överhärde (located in the south part of Valbo) and Strömsbro (located in the north part of Gavle). Purpose of this report is to measure the dissolved oxygen content in the aquifer throughout the whole area to investigate where the infiltration from the nearby Gavle River occurs. The aim of the study is to get a better understanding of the complexity of the Valbo ridge. The measurements will help to verify or modify the conceptual model of the directions of water flow in the Valbo ridge, developed by Midvatten AB. Dissolved oxygen content was measured through ground water pipes. To assess the pipes’ capacity and connection to the aquifer, slug tests were performed. The dissolved oxygen data were analyzed and compared with the conceptual model. The results showed that the dissolved oxygen content in the water supported the conceptual model to a large extent and also gave previously unknown information on some stretches of the ridge. The method shows great potential for additional future studies in Valbo ridge and elsewhere. To expand the study further, a need for more sampling of the aquifer throughout the areas that were not included in this study.

O monitoramento ambiental de forma contínua e em tempo real são desafios da realidade atual dos grandes centros urbanos, com a finalidade de prevenir desastres ambientais que possam pôr em perigo a saúde dos seres humanos e a existência de sistemas biológicos. Na presente tese foram propostos e desenvolvidos sistemas optoeletrônicos portáteis aplicados na detecção de O2, OD e íons de metais pesados, visando seu emprego no monitoramento de sistemas hidrológicos como mares, rios, lagos e lençóis freáticos. A definição final da estrutura do sistema portátil foi atingida após o desenvolvimento sistemático de diferentes ensaios experimentais. Primeiramente, foram estudadas e analisadas matrizes hospedeiras em estado sólido que fossem capazes de hospedar sistemas moleculares corantes sensíveis a certas substâncias específicas. A seguir, foi proposta e executada a integração direta dos filmes hospedeiros, dopados com moléculas corantes ativas, diretamente na superfície ativa de dispositivos fotodetectores para detecção de O2 e OD. Os resultados obtidos com estes sistemas que integram o detector e o filme ativo mostraram o mesmo nível de desempenho aos espectrômetros de bancada. Finalmente, de posse destes resultados, foi projetado e desenvolvido um sistema colorimétrico e fluorimétrico portátil e embarcado em uma placa de aquisição (myRIO-1900) da National Instruments, aplicado na detecção e classificação de íons metálicos. Destaque principal é outorgado à aplicação do colorímetro que, juntamente com o processamento de sinais e análises de padrões, utilizando o método de discriminante de Fisher, permitiu obter resultados excelentes na detecção e classificação dos íons de Pb2+, Cd2+, Zn2+, Cu2+, Fe3+ e Ni2+, com os mesmos níveis de desempenho que os obtidos a partir de espectrômetros de bancada de elevada resolução espectral. O sistema portátil desenvolvido sugere sua aplicação no controle ambiental in situ e em tempo real, podendo ser integrado em uma rede de sensores que possam fornecer dados de maneira contínua e receber comandos de centros de controle de monitoramento ambiental. No entanto, seria necessária a formulação de algoritmos eficientes no processo de mineração de dados da rede de sensores. / The continuous and in real time environmental monitoring are challenges of the current days of large urban centers, with the aim of preventing environmental disasters that could endanger human health and the existence of biological systems. In this thesis we have proposed and developed portable optoelectronic systems applied to the detection of O2, OD and heavy metal ions, aiming its use in monitoring hydrological systems such as oceans, rivers, lakes and groundwater. The final definition of the portable system structure was achieved after the systematic development of different experimental assays. First, host matrices were studied and analyzed in solid state which were able to host dye molecular systems sensitive to certain substances. Then, we proposed and executed the direct integration of the host film, doped with active dye molecules directly on the active surface of photodetector devices to the detection of O2 and OD. The results obtained with these systems that integrate the detector and the active film showed the same level of performance than those of benchtop spectrometers. Finally, with these results, we designed and developed a colorimetric and fluorimetric portable system with an embedded acquisition board (myRIO-1900) from National Instruments, applied to the detection and classification of metal ions. Main focus is given to the application of the colorimeter which, along with the signal processing and pattern analysis using the Fisher discriminant method, allowed to obtain excellent results in the detection and classification of Pb2+, Cd2+, Zn2+, Cu2+, Fe3+ and Ni2+ ions, with the same level of performance related to those obtained from high spectral resolution benchtop spectrometers. The portable system developed in the present thesis suggests its application in environmental control in situ and in real time, so that it can be integrated in a network of sensors that may provide continuous data and receive commands from environmental monitoring control center; nevertheless, requiring for that the development of efficient algorithms in data mining process of the sensor network.

O monitoramento ambiental de forma contínua e em tempo real são desafios da realidade atual dos grandes centros urbanos, com a finalidade de prevenir desastres ambientais que possam pôr em perigo a saúde dos seres humanos e a existência de sistemas biológicos. Na presente tese foram propostos e desenvolvidos sistemas optoeletrônicos portáteis aplicados na detecção de O2, OD e íons de metais pesados, visando seu emprego no monitoramento de sistemas hidrológicos como mares, rios, lagos e lençóis freáticos. A definição final da estrutura do sistema portátil foi atingida após o desenvolvimento sistemático de diferentes ensaios experimentais. Primeiramente, foram estudadas e analisadas matrizes hospedeiras em estado sólido que fossem capazes de hospedar sistemas moleculares corantes sensíveis a certas substâncias específicas. A seguir, foi proposta e executada a integração direta dos filmes hospedeiros, dopados com moléculas corantes ativas, diretamente na superfície ativa de dispositivos fotodetectores para detecção de O2 e OD. Os resultados obtidos com estes sistemas que integram o detector e o filme ativo mostraram o mesmo nível de desempenho aos espectrômetros de bancada. Finalmente, de posse destes resultados, foi projetado e desenvolvido um sistema colorimétrico e fluorimétrico portátil e embarcado em uma placa de aquisição (myRIO-1900) da National Instruments, aplicado na detecção e classificação de íons metálicos. Destaque principal é outorgado à aplicação do colorímetro que, juntamente com o processamento de sinais e análises de padrões, utilizando o método de discriminante de Fisher, permitiu obter resultados excelentes na detecção e classificação dos íons de Pb2+, Cd2+, Zn2+, Cu2+, Fe3+ e Ni2+, com os mesmos níveis de desempenho que os obtidos a partir de espectrômetros de bancada de elevada resolução espectral. O sistema portátil desenvolvido sugere sua aplicação no controle ambiental in situ e em tempo real, podendo ser integrado em uma rede de sensores que possam fornecer dados de maneira contínua e receber comandos de centros de controle de monitoramento ambiental. No entanto, seria necessária a formulação de algoritmos eficientes no processo de mineração de dados da rede de sensores. / The continuous and in real time environmental monitoring are challenges of the current days of large urban centers, with the aim of preventing environmental disasters that could endanger human health and the existence of biological systems. In this thesis we have proposed and developed portable optoelectronic systems applied to the detection of O2, OD and heavy metal ions, aiming its use in monitoring hydrological systems such as oceans, rivers, lakes and groundwater. The final definition of the portable system structure was achieved after the systematic development of different experimental assays. First, host matrices were studied and analyzed in solid state which were able to host dye molecular systems sensitive to certain substances. Then, we proposed and executed the direct integration of the host film, doped with active dye molecules directly on the active surface of photodetector devices to the detection of O2 and OD. The results obtained with these systems that integrate the detector and the active film showed the same level of performance than those of benchtop spectrometers. Finally, with these results, we designed and developed a colorimetric and fluorimetric portable system with an embedded acquisition board (myRIO-1900) from National Instruments, applied to the detection and classification of metal ions. Main focus is given to the application of the colorimeter which, along with the signal processing and pattern analysis using the Fisher discriminant method, allowed to obtain excellent results in the detection and classification of Pb2+, Cd2+, Zn2+, Cu2+, Fe3+ and Ni2+ ions, with the same level of performance related to those obtained from high spectral resolution benchtop spectrometers. The portable system developed in the present thesis suggests its application in environmental control in situ and in real time, so that it can be integrated in a network of sensors that may provide continuous data and receive commands from environmental monitoring control center; nevertheless, requiring for that the development of efficient algorithms in data mining process of the sensor network.

Made available in DSpace on 2016-08-10T10:31:06Z (GMT). No. of bitstreams: 1 CORACI DE PAULA.pdf: 1061738 bytes, checksum: 7cb8fb72afb31a762050eb17ad1c9925 (MD5) Previous issue date: 2009-09-30 / The present study aimed to evaluate the effect of eugenol on the lambaris survival (Astyanax sp) at different concentration and temperatures, contributing to transportations technics. Six hundred and twenty five fish with 4,28±2,75 g 6,62±1,18 cm were used. Eugenol concentrations of 7,5; 9,5; 11,5; 13,5 and 15,5 mg/L were tested at 05 replications. Each concentration was submitted to temperatures of 20, 22, 24, 26 and 28°C, totalizing 125 experimental units. Each unit received 05 fishes, wich were kept of 01 liter volume until the beginning of mortality, when the analyses of pH, ammonia, and dissolved oxygen started. The results obtained showed that the beginning of mortality, pH and ammonia were significantly influenced by the temperature and eugenol concentrations. The dissolved oxygen was influenced only by the eugenol concentration. Considering the temperature, it was registred that temperatures between 20 and 28°C caused mortality earlier than temperatures around 24°C. It was concluded that eugenol concentrations between 7,5 and 15,5 mg/L are appropriated for this specie. Besides, it was observed temperature of 24°C and eugenol concentrations in the range of 7,5 and 9,5 mg/L indicated to use in the transportation of lambari. / O objetivo deste trabalho foi avaliar o efeito do eugenol na sobrevida de lambaris (Astyanax sp) em diferentes concentrações e temperaturas, visando aprimorar as técnicas de transporte. Foram utilizados 625 peixes com 4,28 ± 2,75 g 6,62 ± 1,18 cm, submetidos a concentrações de eugenol de 7,5; 9,5; 11,5; 13,5 e 15,5 mg/L sob diferentes temperaturas (20, 22, 24, 26 e 28°C), totalizando 25 tratamentos com 05 repetições cada. Assim foram utilizados 125 unidades experimentais de 1litro cada, onde os peixes permaneceram até se observar o início da mortalidade, momento em que encerrava o ensaio e procedia a análise do pH, oxigênio dissolvido, amônia da água e biometria dos peixes. Os resultados mostraram que a temperatura e o eugenol influenciaram no início da mortalidade, pH e amôna, no entando, o oxigênio dissolvido foi influenciado apenas pelas concentrações do eugenol. Temperaturas em torno de 20 e 28°C parecem acelerar a mortalidade dos peixes, comparando-se com temperaturas próximas a 24°C. Pode-se concluir que concentrações de eugenol de 7,5 a 15,5 mg/L são apropriadas para a espécie em questão. Paralelamente conclui-se que a temperatura de 24°C e concentração do eugenol na faixa de 7,5 a 9,5são as mais indicadas para o uso no transporte do lambari.

A presente proposta de estudo refere-se à identificação de modelo linear empírico para processo de transferência de oxigênio das bolhas de ar para o meio líquido, simulação para testes de controle e implementação de uma estratégia de controle em escala laboratorial em tempo real. Os ensaios de controle foram na unidade experimental (canal aberto) existente no laboratório de hidráulica ambiental o qual foi adaptado para aeração com sensores, atuadores, microcomputador, interface AD/DA. Foi testado o algoritmo de controle do tipo convencional PID (Proportional Integral Derivative control). Com os resultados obtidos da perturbação degrau na variável de entrada (alimentação do ar) foi possível identificar o sistema como um modelo de primeira ordem, suficiente para os propósitos de controle. Baseado na identificação, foi ajustado um controlador PID para implementação experimental. A principal contribuição desta pesquisa consistiu no emprego de uma estratégia de controle adequada na prática, ao processo de aeração. / The current study refers to the identification of an empirical linear model for the oxygen transfer process from air bubbles to liquid, control tests simulation and implementation of a control strategy at real time in laboratory scale. The control tests were carried out at the experimental unit (open channel) located at the environmental hydraulic laboratory which was adapted to aeration process with sensors, actuators, microcomputer, AD/DA interface. The classic PID (Proportional Integral Derivative control) algorithm was tested. With results from step response of input variable (air feeding) it was possible to identify the system as a first order model, enough for the control purposes. Based on the identification, a PID controller was adjusted for the experimental implementation. The main contribution of this work consisted of the employment of an appropriate control strategy to the aeration process in practice.