Higher-Derivative Two-Dimensional Massive Fermion Theories

We consider the canonical quantization of a generalized two-dimensional massive fermion theory containing higher odd-order derivatives. The requirements of Lorentz invariance, hermiticity of the Hamiltonian and absence of tachyon excitations suffice to fix the mass term, which contains a derivative coupling. We show that the basic quantum excitations of a higher-derivative theory of order 2N+1 consist of a physical usual massive fermion, quantized with positive metric, plus 2N unphysical massless fermions, quantized with opposite metrics. The positive metric Hilbert subspace, which is isomorphic to the space of states of a massive free fermion theory, is selected by a subsidiary-like condition. Employing the standard bosonization scheme, the equivalent boson theory is derived. The results obtained are used as a guideline to discuss the solution of a theory including a current-current interaction.Comment: 23 pages, Late

Estudo da condutividade hidráulica dos solos na area do entorno do projeto de irrigação salitre

bitstream/CNPS-2010/14865/1/doc92-2007est-condut-hidraulica.pd

Activated sludge monitoring of a wastewater treatment plant using image analysis and partial least squares

The wastewater treatment plant activated sludge is a complex ecosystem mainly of bacteria and protozoa. Bacteria agglomerate as settleable robust aggregates leading to low organic matter and turbidity final effluents. However, when the operating conditions are not perfect some malfunctions may occur leading to bulking problems. Classical methods to survey the bacteria aggregation and contents resided on manual counting which are, rather tiring, imprecise and time-consuming urging the development of faster automated image analysis methods. Therefore, the prime objective of this work resided on surveying the activated sludge filamentous bacteria and aggregates contents and morphology, and establish relationships between the biomass and some operating parameters by multivariable statistical techniques. One of the main conclusions of this work resided on the determination of a filamentous, rather than a zoogleal, bulking problem in the course of this survey. This conclusion could be withdrawn by the strong resemblance between the sludge volume index and the filaments/aggregates contents ratio behaviour throughout the experiment time and by the high filamentous bacteria/suspended solids ratio (above 10000 mm/mg) which clearly indicates the existence of a filamentous bulking problem. Furthermore, an in-depth statistical analysis revealed that the filamentous bacteria/suspended solids ratio parameter may be used, at some extent, to monitor the SVI behaviour in a wastewater treatment plant aeration tank, whereas the suspended solids could be satisfactory monitored by the total aggregates area parameter. However, these results refer only to a wastewater treatment plant experiencing a bulking phenomenon and further studies should be developed in normal plants

Activated sludge monitoring of a wastewater treatment plant using image analysis and partial least squares regression

The biomass present in awastewater treatment plantwas surveyed and their morphological properties related with operating parameters such as the total suspended solids (TSS) and sludge volume index (SVI). For that purpose image analysis was used to provide the morphological data subsequently treated by partial least squares regression (PLS) multivariable statistical technique. The results denoted the existence of a severe bulking problem of non-zoogleal nature and the PLS analysis revealed a strong relationship between the TSS and the total aggregates area as well as a close correlation between the filamentous bacteria per suspended solids ratio and the SVI.Fundação para a Ciência e a Tecnologia (FCT) – PRAXIS XXI/BD/20325/99

Aplicações de técnicas de análise de imagem em microbiologia ambiental

São evidenciadas algumas aplicações da análise de imagem em microbiologia ambiental, nomeadamente: o reconhecimento e identificação automática de algumas espécies de protozoários presentes em estações de tratamento de águas residuais; o estudo da influência de três tóxicos na mobilidade do protozoário ciliado Tetrahymena pyriformis em meio líquido; a correlação entre actividade metanogénica, velocidade de sedimentação e parâmetros morfológicos de agregados microbianos em digestores anaeróbios; e finalmente o estudo da correlação entre as actividades metanogénicas acetoclástica e hidrogenofílica e a fluorescência de um consórcio de microrganismos de um digestor anaeróbio. Procura-se assim demonstrar a utilidade das técnicas de análise de imagem na monitorização quer de processos de tratamento de águas resíduais quer da própria qualidade ambiental.Ministério da Ciência e Tecnologia. Instituto de Cooperação Científica e Tecnológica Internacional (ICCTI).Embaixada de França em Portugal

Distinção de fenómenos de bulking em lamas activadas por técnicas de análise de imagem

No corrente trabalho pretendeu-se detectar e identificar diferentes tipos de perturbações em lamas activadas (bulking filamentoso, bulking viscoso e crescimento de flocos pin point) por técnicas de processamento e análise de imagem. Para o efeito foram determinados os parâmetros operacionais sólidos suspensos totais (SST) e índice volumétrico de lamas (IVL), assim como diversos parâmetros morfológicos (conteúdo e morfologia da biomassa agregada e filamentosa), obtidos por análise de imagem. Os resultados obtidos permitiram o esclarecimento das diferentes inter-relações presentes entre cada uma das condições estudadas e os parâmetros que caracterizaram a biomassa microbiana, assim como a aferição do parâmetro operacional IVL, a partir da caracterização da biomassa

Characterisation of activated sludge abnormalities by image analysis and multivariate statistics

The ability to distinguish between different types of abnormalities affecting wastewater activated sludge systems, by means of image analysis and chemometrics methodologies, was studied in the current work. Three experiments were performed in a pilot plant activated sludge system, during periods ranging from 47 to 85 days each, in a total of 108 samples, reflecting filamentous bulking, zoogleal bulking and pin point flocs conditions. These samples were further analyzed for the determination of image analysis parameters and of the most commonly surveyed operating parameters. Regarding the image analysis methodology three aliquots of each sample were visualized by bright field and fluorescence microscopy, and a total of 150 images per sample were acquired. These images were then treated by image processing software allowing the study of the contents and morphology of aggregated and filamentous bacteria, resulting in the determination of parameters reflecting the aggregates size distribution, filamentous to aggregated biomass ratio, and biomass viability. A Principal Components Analysis was then carried out on the obtained data to identify each studied conditions, with cross-validation (CV) as the criterion to determine the optimal number of significant components. Although the optimal number of principal components, obtained by the CV method, was found to be 7, explaining 91.9 % of the data variability, it was found that the use of the 2 first principal components (explaining 61.2 % of the data variability) allowed to clearly identify all three conditions (pin point flocs, filamentous and zoogleal bulking). In fact, the samples score plot in these two principal components presented three distinct and non-overlapping zones, reflecting the three different studied conditions. Furthermore, it allowed for the identification and exclusion of 5 outliers within the dataset. Analysing the loading contribution for these 2 first principal components, it was evident the preponderance of the aggregates size distribution and of the filamentous to aggregated biomass ratio, reflecting the importance of these two groups of parameters in the identification and enlightenment of activated sludge abnormalities

Improved image analysis procedures for monitoring activated sludge systems with filamentous bulking

Activated sludge systems are frequently used in wastewater treatment plant. This process is the most suitable and studied system. However, several problems are being always detected, such as filamentous bulking. Filamentous bulking is typically caused by an overabundance of filamentous organisms that interfere with the settling and compaction process. This phenomenon can be studied and related with settling parameters by automated image analysis using different microscopy acquisitions. However, by using these standard image analysis procedures some relevant information about the state of the sludge is enclosed. Conventional routines, using monochrome images are not suitable to detect the filamentous bacteria which are gram-positive or gram-negative. Moreover, the traditional image acquisition methodologies are not capable to detect both viable and damaged bacteria present within the sludge. Presently, the gram-stain evaluation is performed by visual inspection and manual counting using a microscope which is a tedious procedure. Also, to overcome the lack of viability information, an epifluorescence staining method composed with two nucleic acid-binding stains can be used. For this study, a lab-scale activated sludge reactor was monitored during 100 days through image analysis information and the operational parameters were modified inducing filamentous bulking. Morphological changes were investigated by using new acquisition methods such as epifluorescence staining LIVE/DEAD® BacLight™ Bacterial Viability Kit, the LIVE BacLight™ Bacterial Gram Stain Kit and the traditional bright field. The overall results revealed an improvement of the sludge morphological characterisation, combining these new image analysis procedures with the conventional routines