Dinâmica do fósforo em cultivo heterotrófico e produção de compostos celulares por cianobactéria integrado a biorrefinarias agroindustriais

O objetivo desta tese foi avaliar a dinâmica do fósforo em cultivo heterotrófico e produção de compostos celulares por Aphanothece microscopica Nägeli visando avaliar a perspectiva de implementação de uma biorrefinaria microalgal. Desta forma, foi avaliado o comportamento do micro-organismo em estudo no cultivo heterotrófico, utilizando como meio de cultivo o efluente de laticínios. O trabalho foi desenvolvido em 3 etapas. Em um primeiro momento foi avaliada a influência da temperatura (20 e 30°C) e os valores máximos e mínimos de nutrientes, em especial do fósforo dissolvido reativo (PDR), disponíveis no efluente de laticínio, na remoção de nutrientes. Os resultados demonstraram que a concentração inicial de fósforo dissolvido e a temperatura exerceram influência no crescimento celular e na eficiência de remoção de nutrientes. Em termos de otimização de processo os cultivos conduzidos a 20°C e maiores concentrações de PDR (5,5 mg.L-1 ) no efluente de laticínio, foram os mais eficientes na conversão de poluentes em biomassa e remoção de nutrientes. A segunda etapa foi desenvolvida com o objetivo de avaliar a dinâmica de distribuição de fósforo na fase líquida e sólida do reator heterotrófico, quando o efluente de laticínio foi tratado pela Aphanothece microscopica Nägeli, a 20°C e nas máximas concentrações de fósforo dissolvido encontradas no efluente. Foi demonstrado que as formas fosforadas na fase líquida do reator se caracterizam pela predominância da fração dissolvida em comparação à particulada e por apresentar como fração predominante a de fósforo orgânico. No que se refere à fase sólida, ficou demonstrado que a Aphanothece microscopica Nägeli, quando cultivada heterotroficamente apresenta 3,8 vezes mais fósforo que o requerido para o crescimento celular. Ficando demonstrado ainda que a remoção biológica de fósforo por Aphanothece microscopica Nägeli pode resultar em substanciais aportes financeiros para as estações de tratamento de efluentes. Uma terceira etapa foi desenvolvida, a qual teve como objetivo avaliar a estimativa de produção de compostos celulares por Aphanothece microscopica Nägeli, a partir do efluente de laticínio, bem como o efeito da redução de temperatura de cultivo no teor de lipídios , no momento em que é obtida a máxima concentração deste componente celular, nas condições otimizadas.Foi obtido na fase logarítmica de crescimento, concentrações de 41,8 % de proteinas, carboidratos 28,5 %, lipídios 10,4 % e minerais 10,8 %. O maior teor de lipídio registrado a 20°C correspondeu a biomassa analisada na fase logarítmica.Com a redução da temperatura para 5°C por um período de 30 h é possível obter concentrações de lipídios 2,4 vezes superior ao registrado na fase logarítmica a 20 °C. No entanto, não foram indicadas diferenças significativas (p≤0,05) em função da temperatura entre as concentrações de lipídios obtidas para a biomassa a 10°C em 40 h. O perfil de ácidos graxos da biomassa gerada a 20°C, apresentou como ácidos graxos majoritários, os ácidos graxos: palmítico, oléico, γ-linolênico, palmitoleico e esteárico, resultando um aumento na concentração de ácidos graxos saturados as espensa dos insaturados, quando a temperatura é reduzida. Em paralelo,um reator heterotrófico descontinuo foi definido, ficando demonstrado que a extrapolação da operação em batelada para contínua requer um biorreator heterotrófico com volume útil de trabalho de 240,51 m 3 , permitindo tratar 950 m3 diários de efluente, gerando 11,8 kg.d-1 de biomassa útil para produção de compostos celulares por Aphanothece microscopica Nägeli, visando à simultânea remoção de matéria orgânica, nitrogênio total e fósforo total, gerando insumos que podem suportar a implementação de uma biorrefinaria microalgal.

An identification procedure of multi-input Wiener models for the distortion analysis of nonlinear circuits

In this contribution, a system identification procedure of a two-input Wiener model suitable for the analysis of the disturbance behavior of integrated nonlinear circuits is presented. The identified block model is comprised of two linear dynamic and one static nonlinear block, which are determined using an parameterized approach. In order to characterize the linear blocks, an correlation analysis using a white noise input in combination with a model reduction scheme is adopted. After having characterized the linear blocks, from the output spectrum under single tone excitation at each input a linear set of equations will be set up, whose solution gives the coefficients of the nonlinear block. By this data based black box approach, the distortion behavior of a nonlinear circuit under the influence of an interfering signal at an arbitrary input port can be determined. Such an interfering signal can be, for example, an electromagnetic interference signal which conductively couples into the port of consideration. © 2011 Author(s).

Generating Discriminative Objective Proposals via Submodular Ranking

Object recognition has long been a core problem in computer vision. To improve object spatial support and speed up object localization for object recognition, generating high-quality category-independent object proposals as the input for object recognition system has drawn attention recently. Given an image, we generate a limited number of high-quality and category-independent object proposals in advance and used as inputs for many computer vision tasks. We present an efficient dictionary-based model for image classification task. We further extend the work to a discriminative dictionary learning method for tensor sparse coding. In the first part, a multi-scale greedy-based object proposal generation approach is presented. Based on the multi-scale nature of objects in images, our approach is built on top of a hierarchical segmentation. We first identify the representative and diverse exemplar clusters within each scale. Object proposals are obtained by selecting a subset from the multi-scale segment pool via maximizing a submodular objective function, which consists of a weighted coverage term, a single-scale diversity term and a multi-scale reward term. The weighted coverage term forces the selected set of object proposals to be representative and compact; the single-scale diversity term encourages choosing segments from different exemplar clusters so that they will cover as many object patterns as possible; the multi-scale reward term encourages the selected proposals to be discriminative and selected from multiple layers generated by the hierarchical image segmentation. The experimental results on the Berkeley Segmentation Dataset and PASCAL VOC2012 segmentation dataset demonstrate the accuracy and efficiency of our object proposal model. Additionally, we validate our object proposals in simultaneous segmentation and detection and outperform the state-of-art performance. To classify the object in the image, we design a discriminative, structural low-rank framework for image classification. We use a supervised learning method to construct a discriminative and reconstructive dictionary. By introducing an ideal regularization term, we perform low-rank matrix recovery for contaminated training data from all categories simultaneously without losing structural information. A discriminative low-rank representation for images with respect to the constructed dictionary is obtained. With semantic structure information and strong identification capability, this representation is good for classification tasks even using a simple linear multi-classifier.

Remoção de metais pesados em efluentes sintéticos utilizando vermiculita como adsorvente

Heavy metals are used in many industrial processestheirs discard can harm fel effects to the environment, becoming a serious problem. Many methods used for wastewater treatment have been reported in the literature, but many of them have high cost and low efficiency. The adsorption process has been used as effective for the metal remoal ions. This paper presents studies to evaluate the adsorption capacity of vermiculite as adsorbent for the heavy metals removal in a synthetic solution. The mineral vermiculite was characterized by differents techniques: specific surface area analysis by BET method, X-ray diffraction, raiosX fluorescence, spectroscopy in the infraredd region of, laser particle size analysis and specific gravity. The physical characteristics of the material presented was appropriate for the study of adsorption. The adsorption experiments weredriveal finite bath metod in synthetic solutions of copper, nickel, cadmium, lead and zinc. The results showed that the vermiculite has a high potential for adsorption, removing about 100% of ions and with removal capacity values about 85 ppm of metal in solution, 8.09 mg / g for cadmium, 8.39 mg/g for copper, 8.40 mg/g for lead, 8.26 mg/g for zinc and 8.38 mg/g of nickel. The experimental data fit in the Langmuir and Freundlich models. The kinetic datas showed a good correlation with the pseudo-second order model. It was conducteas a competition study among the metals using vermiculiti a adsorbent. Results showed that the presence of various metals in solution does not influence their removal at low concentrations, removing approximat wasely 100 % of all metals present in solutions

A docência no piano : representações sociais de professores de escolas de música em Taguatinga

Dissertação (mestrado)—Universidade de Brasília, Instituto de Artes, Departamento de Música, Programa de Pós-graduação em Música, 2015.

Comportamento magnético de compósitos de matriz polimérica com adição de ferritas

Polymer matrix composites offer advantages for many applications due their combination of properties, which includes low density, high specific strength and modulus of elasticity and corrosion resistance. However, the application of non-destructive techniques using magnetic sensors for the evaluation these materials is not possible since the materials are non-magnetizable. Ferrites are materials with excellent magnetic properties, chemical stability and corrosion resistance. Due to these properties, these materials are promising for the development of polymer composites with magnetic properties. In this work, glass fiber / epoxy circular plates were produced with 10 wt% of cobalt or barium ferrite particles. The cobalt ferrite was synthesized by the Pechini method. The commercial barium ferrite was subjected to a milling process to study the effect of particle size on the magnetic properties of the material. The characterization of the ferrites was carried out by x-ray diffraction (XRD), field emission gun scanning electron microscopy (FEG-SEM) and vibrating sample magnetometry (VSM). Circular notches of 1, 5 and 10 mm diameter were introduced in the composite plates using a drill bit for the non-destructive evaluation by the technique of magnetic flux leakage (MFL). The results indicated that the magnetic signals measured in plates with barium ferrite without milling and cobalt ferrite showed good correlation with the presence of notches. The milling process for 12 h and 20 h did not contribute to improve the identification of smaller size notches (1 mm). However, the smaller particle size produced smoother magnetic curves, with fewer discontinuities and improved signal-to-noise ratio. In summary, the results suggest that the proposed approach has great potential for the detection of damage in polymer composites structures

Credit risk & forward price models

Doutoramento em Gestão

Supressão do ruído de rolamento superficial utilizando a transformada Curvelet

Among the many types of noise observed in seismic land acquisition there is one produced by surface waves called Ground Roll that is a particular type of Rayleigh wave which characteristics are high amplitude, low frequency and low velocity (generating a cone with high dip). Ground roll contaminates the relevant signals and can mask the relevant information, carried by waves scattered in deeper regions of the geological layers. In this thesis, we will present a method that attenuates the ground roll. The technique consists in to decompose the seismogram in a basis of curvelet functions that are localized in time, in frequency, and also, incorporate an angular orientation. These characteristics allow to construct a curvelet filter that takes in consideration the localization of denoise in scales, times and angles in the seismogram. The method was tested with real data and the results were very good

Détection de mouvements dans des séquences d’images basée sur la dynamique de supraconductivité

Le but de ce travail est d’étudier la faisabilité de la détection de mouvements dans des séquences d’images en utilisant l’équation de continuité et la dynamique de supraconductivité. Notre approche peut être motivée par le fait que l’équation de continuité apparait dans plusieurs techniques qui estiment le flot optique. Un grand nombre de techniques qui utilisent les flots optiques utilisent une contrainte appelée contrainte de l’invariance lumineuse. La dynamique de supraconductivité nous permet de nous affranchir de la contrainte de l’invariance lumineuse. Les expériences se feront avec la base de données de séquences d’images CDNET 2014. Pour obtenir les résultats numériques en terme de score F1, une combinaison sera faite par la suite entre la dynamique de supraconductivité et un méchanisme d’attention qui est un résumé des vérites de terrain.

Photo Degradation of Cotnaminants of Emerging concern (CECs) under Simulated Solar Radiation: Implications for their Environmental Fate

Contaminants of emerging concern (CECs) are continuously being released into the environment mainly because of their incomplete removal in the sewage treatment plants (STPs). The CECs selected for the study include antibiotics (macrolides, sulfonamides and ciprofloxacin), sucralose (an artificial sweetener) and dioctyl sulfosuccinate (DOSS, chemical dispersant used in the Deepwater Horizon oil spill). After being discharged into waterways from STPs, photo degradation is a key factor in dictating the environmental fate of antibiotics and sucralose. Photodegradation efficiency depends on many factors such as pH of the matrix, matrix composition, light source and structure of the molecule. These factors exert either synergistic or antagonistic effects in the environment and thus experiments with isolated factors may not yield the same results as the natural environmental processes. Hence in the current study photodegradation of 13 CECs (antibiotics, sucralose and dicotyl sulfosuccinate) were evaluated using natural water matrices with varying composition (deionized water, fresh water and salt water) as well as radiation of different wavelengths (254 nm, 350 nm and simulated solar radiation) in order to mimic natural processes. As expected the contribution of each factor on the overall rate of photodegradation is contaminant specific, for example under similar conditions, the rate in natural waters compared to pure water was enhanced for antibiotics (2-11 fold), significantly reduced for sucralose (no degradation seen in natural waters) and similar in both media for DOSS. In general, it was observed that the studied compounds degraded faster at 254 nm, while when using a simulated sunlight radiation the rate of photolysis of DOSS increased and the rates for antibiotics decreased in comparison to the 350 nm radiation. The photo stability of the studied CECs followed the order sucralose > DOSS > macrolides > sulfonamides > ciprofloxacin and a positive relationship was observed between photo stability and their ubiquitous presence in natural aquatic matrices. An online LC-MS/MS method was developed and validated for sucralose and further applied to reclaimed waters (n =56) and drinking waters (n = 43) from South Florida. Sucralose was detected in reclaimed waters with concentrations reaching up to 18 µg/L. High frequency of detection (> 80%) in drinking waters indicate contamination of ground waters in South Florida by anthropogenic activity.

Effect of gamma-irradiation on total organic carbon and trihalomethane formation potential

This research was conducted to study the use of radiation in water treatment as an alternative to chlorination which has caused health concerns due to the formation of harmful disinfection by-products. Groundwater solutions from the Biscayne aquifer were radiated with Cobalt-60 gamma radiation and studied for changes in dissolved organic carbon (DOC), UV absorbance at 254 nm (UV254), fluorescence and trihalomethane formation potential (THMFP). Molecular fractionations were conducted by ultrafiltration. Effect of the combination of radiation/peroxide was studied for DOC and UV254. Radiation showed significant removal in DOC and THMFP. Similar results were seen in the fluorescence and UV absorbance experiments. Radiation/peroxide did not improve the DOC removal. Radiation of the groundwater samples broke the larger molecular weight fractions in to smaller fractions.

Binocular functional architecture for detection of contrast-modulated gratings

Combination of signals from the two eyes is the gateway to stereo vision. To gain insight into binocular signal processing, we studied binocular summation for luminance-modulated gratings (L or LM) and contrast-modulated gratings (CM). We measured 2AFC detection thresholds for a signal grating (0.75 c/deg, 216msec) shown to one eye, both eyes, or both eyes out-of-phase. For LM and CM, the carrier noise was in both eyes, even when the signal was monocular. Mean binocular thresholds for luminance gratings (L) were 5.4dB better than monocular thresholds - close to perfect linear summation (6dB). For LM and CM the binocular advantage was again 5-6dB, even when the carrier noise was uncorrelated, anti-correlated, or at orthogonal orientations in the two eyes. Binocular combination for CM probably arises from summation of envelope responses, and not from summation of these conflicting carrier patterns. Antiphase signals produced no binocular advantage, but thresholds were about 1-3dB higher than monocular ones. This is not consistent with simple linear summation, which should give complete cancellation and unmeasurably high thresholds. We propose a three-channel model in which noisy monocular responses to the envelope are binocularly combined in a contrast-weighted sum, but also remain separately available to perception via a max operator. Vision selects the largest of the three responses. With in-phase gratings the binocular channel dominates, but antiphase gratings cancel in the binocular channel and the monocular channels mediate detection. The small antiphase disadvantage might be explained by a subtle influence of background responses on binocular and monocular detection.

Power spectrum model of visual masking: simulations and empirical data

In the study of the spatial characteristics of the visual channels, the power spectrum model of visual masking is one of the most widely used. When the task is to detect a signal masked by visual noise, this classical model assumes that the signal and the noise are previously processed by a bank of linear channels and that the power of the signal at threshold is proportional to the power of the noise passing through the visual channel that mediates detection. The model also assumes that this visual channel will have the highest ratio of signal power to noise power at its output. According to this, there are masking conditions where the highest signal-to-noise ratio (SNR) occurs in a channel centered in a spatial frequency different from the spatial frequency of the signal (off-frequency looking). Under these conditions the channel mediating detection could vary with the type of noise used in the masking experiment and this could affect the estimation of the shape and the bandwidth of the visual channels. It is generally believed that notched noise, white noise and double bandpass noise prevent off-frequency looking, and high-pass, low-pass and bandpass noises can promote it independently of the channel's shape. In this study, by means of a procedure that finds the channel that maximizes the SNR at its output, we performed numerical simulations using the power spectrum model to study the characteristics of masking caused by six types of one-dimensional noise (white, high-pass, low-pass, bandpass, notched, and double bandpass) for two types of channel's shape (symmetric and asymmetric). Our simulations confirm that (1) high-pass, low-pass, and bandpass noises do not prevent the off-frequency looking, (2) white noise satisfactorily prevents the off-frequency looking independently of the shape and bandwidth of the visual channel, and interestingly we proved for the first time that (3) notched and double bandpass noises prevent off-frequency looking only when the noise cutoffs around the spatial frequency of the signal match the shape of the visual channel (symmetric or asymmetric) involved in the detection. In order to test the explanatory power of the model with empirical data, we performed six visual masking experiments. We show that this model, with only two free parameters, fits the empirical masking data with high precision. Finally, we provide equations of the power spectrum model for six masking noises used in the simulations and in the experiments.

Détection de mouvements dans des séquences d’images basée sur la dynamique de supraconductivité

Le but de ce travail est d’étudier la faisabilité de la détection de mouvements dans des séquences d’images en utilisant l’équation de continuité et la dynamique de supraconductivité. Notre approche peut être motivée par le fait que l’équation de continuité apparait dans plusieurs techniques qui estiment le flot optique. Un grand nombre de techniques qui utilisent les flots optiques utilisent une contrainte appelée contrainte de l’invariance lumineuse. La dynamique de supraconductivité nous permet de nous affranchir de la contrainte de l’invariance lumineuse. Les expériences se feront avec la base de données de séquences d’images CDNET 2014. Pour obtenir les résultats numériques en terme de score F1, une combinaison sera faite par la suite entre la dynamique de supraconductivité et un méchanisme d’attention qui est un résumé des vérites de terrain.

Use of bird carcass removals by urban scavengers to adjust bird-window collision estimates

Carcass removal by scavengers has been identified as one of the largest biases in estimating bird mortality from anthropogenic sources. Only two studies have examined carcass removal by scavengers in an urban environment, and previous estimates of bird-window collision mortality at houses have relied on carcass removal rates from wind turbine studies. We placed a bird carcass and time-lapse camera at 44 houses in Edmonton, Alberta. In total, 166 7-day trials were conducted throughout 2015. Time-to-event (survival) analysis was used to identify covariates that affected removal. The carcass removal rate was determined for use in estimating the number of birds killed from bird-window collisions at houses in Alberta. In total, 67.5% of carcasses were removed. The date the carcass was placed, the year the house was built, and the level of development within 50 m of the house were the covariates that had the largest effect on carcass removal. In calculating our removal rate, the number of detected carcasses in the first 24 hours was adjusted by 1.47 to account for removal by scavengers. Previously collected citizen science data were used to create an estimate of 957,440 bird deaths each year in Alberta as a result of bird-window collisions with houses. This number is based on the most detailed bird-window collision study at houses to date and a carcass removal study conducted in the same area. Similar localized studies across Canada will need to be completed to reduce the biases that exist with the previous bird-window collision mortality estimate for houses in Canada.