Algoritmos gen��ticos: aplica����o na s��ntese de alguns algoritmos de controlo

Mestrado em Engenharia Electrot��cnica e de Computadores. ��rea de Especializa����o de Automa����o e Sistemas.

Logistic optimization in tourism networks

55th European Regional Science Association Congress, Lisbon, Portugal (25-28 August 2015).

Particle agglomeration study in rf silane plasmas: In situ study by polarization-sensitive laser light scattering

To determine self-consistently the time evolution of particle size and their number density in situ multi-angle polarization-sensitive laser light scattering was used. Cross-polarization intensities (incident and scattered light intensities with opposite polarization) measured at 135 degrees and ex situ transmission electronic microscopy analysis demonstrate the existence of nonspherical agglomerates during the early phase of agglomeration. Later in the particle time development both techniques reveal spherical particles again. The presence of strong cross-polarization intensities is accompanied by low-frequency instabilities detected on the scattered light intensities and plasma emission. It is found that the particle radius and particle number density during the agglomeration phase can be well described by the Brownian free molecule coagulation model. Application of this neutral particle coagulation model is justified by calculation of the particle charge whereby it is shown that particles of a few tens of nanometer can be considered as neutral under our experimental conditions. The measured particle dispersion can be well described by a Brownian free molecule coagulation model including a log-normal particle size distribution. (C) 1996 American Institute of Physics.

A industria da corti��a e o seu potencial de inova����o

Este trabalho teve como objectivo a avalia����o da actual situa����o da ind��stria corticeira, o levantamento de eventuais possibilidades de inova����o e o estudo de um caso promissor. Como caso promissor, decidiu-se estudar o efeito da pir��lise nos res��duos de corti��a. A an��lise da situa����o actual da ind��stria corticeira aponta para a procura de novos produtos no sentido de alargar o mercado e promover um melhor escoamento deste recurso natural. Apesar de todos os esfor��os efectuados at�� ao momento, verifica-se que a ind��stria vin��cola continua a ser o principal mercado da corti��a. O avan��o da tecnologia tem permitido o desenvolvimento de novos produtos, alguns ainda em fase de desenvolvimento, e aponta para um potencial de inova����o a v��rios n��veis: ao n��vel do processo de transforma����o, no sentido da sua optimiza����o; ao n��vel do desenvolvimento de novos produtos dado o potencial j�� demonstrado pela corti��a em desenvolvimentos recentes; ao n��vel da valoriza����o de res��duos como, por exemplo, a consolida����o de processo de recupera����o de taninos da ��gua de cozedura, a obten����o de suberina e poliois do p�� e aparas de corti��a e a pir��lise das aparas e p�� de corti��a. Como estudo de caso, efectuou-se o estudo do efeito da pir��lise em res��duos de corti��a natural, para se poder conhecer as caracter��sticas dos produtos obtidos bem como as condi����es ��ptimas de opera����o. Neste fase inicial e optou-se por se analisar as propriedades parte s��lida de modo a saber as altera����es sofridas durante a pir��lise e estas podem apresentar uma mais-valia para o mercado corticeiro. Para efectuar o respectivo trabalho, recorreu-se a um forno pirol��tico horizontal tipo Splitz e utilizou-se corti��a natural com granulometria entre 2,88 e 4,00mm. A pir��lise foi realizada entre a gama de temperaturas de 400 e 900��C e para duas rampas de aquecimento de 5��C/min e 10��C/min. O estudo experimental revela que na gama de temperaturas entre os 600 e 800��C �� onde a carboniza����o do res��duo est�� completa, sendo para essa mesma gama de temperaturas que se verifica, no res��duo carbonoso, um maior teor de carbono. Relativamente ��s rampas de aquecimento estas n��o apresentam efeitos significativos nas massas e teores de carbono no res��duo carbonoso final. Verificouse tamb��m, que o teor de hidrog��nio diminui com o aumento da temperatura. Conclui-se que a pir��lise consegue degradar os res��duos de corti��a levando �� liberta����o de compostos que poder��o ser uma mais-valia.

Environmental impact caused by fungal and particle contamination of Portuguese swine

Social concerns for environmental impact on air, water and soil pollution have grown along with the accelerated growth of pig production. This study intends to characterize air contamination caused by fungi and particles in swine production, and, additionally, to conclude about their eventual environmental impact. Fiftysix air samples of 50 litters were collected through impaction method. Air sampling and particle matter concentration were performed in indoor and also outdoor premises. Simultaneously, temperature and relative humidity were monitored according to the International Standard ISO 7726 ��� 1998. Aspergillus versicolor presents the highest indoor spore counts (>2000 CFU/m3) and the highest overall prevalence (40.5%), followed by Scopulariopsis brevicaulis (17.0%) and Penicillium sp. (14.1%). All the swine farms showed indoor fungal species different from the ones identified outdoors and the most frequent genera were also different from the ones indoors. The distribution of particle size showed the same tendency in all swine farms (higher concentration values in PM5 and PM10 sizes). Through the ratio between the indoor and outdoor values, it was possible to conclude that CFU/m3 and particles presented an eventual impact in outdoor measurements.

A literature review on the optimization of legged robots

Over the last two decades the research and development of legged locomotion robots has grown steadily. Legged systems present major advantages when compared with ���traditional��� vehicles, because they allow locomotion in inaccessible terrain to vehicles with wheels and tracks. However, the robustness of legged robots, and especially their energy consumption, among other aspects, still lag behind mechanisms that use wheels and tracks. Therefore, in the present state of development, there are several aspects that need to be improved and optimized. Keeping these ideas in mind, this paper presents the review of the literature of different methods adopted for the optimization of the structure and locomotion gaits of walking robots. Among the distinct possible strategies often used for these tasks are referred approaches such as the mimicking of biological animals, the use of evolutionary schemes to find the optimal parameters and structures, the adoption of sound mechanical design rules, and the optimization of power-based indexes.

Sensing Cloud Optimization applied to a non-convex constrained economical dispatch

Confer��ncia: 39th Annual Conference of the IEEE Industrial-Electronics-Society (IECON) - NOV 10-14, 2013

Optimization of Cu(II) biosorption onto ascophyllum nodosum by factorial design methodology

A Box���Behnken factorial design coupled with surface response methodology was used to evaluate the effects of temperature, pH and initial concentration in the Cu(II) sorption process onto the marine macroalgae Ascophyllum nodosum. The effect of the operating variables on metal uptake capacitywas studied in a batch system and a mathematical model showing the influence of each variable and their interactions was obtained. Study ranges were 10���40��C for temperature, 3.0���5.0 for pH and 50���150mgL���1 for initial Cu(II) concentration. Within these ranges, the biosorption capacity is slightly dependent on temperature but markedly increases with pH and initial concentration of Cu(II). The uptake capacities predicted by the model are in good agreement with the experimental values. Maximum biosorption capacity of Cu(II) by A. nodosum is 70mgg���1 and corresponds to the following values of those variables: temperature = 40��C, pH= 5.0 and initial Cu(II) concentration = 150mgL���1.

Multi-criteria design optimization study of solvent extraction in mixer���settler units

Solvent extraction is considered as a multi-criteria optimization problem, since several chemical species with similar extraction kinetic properties are frequently present in the aqueous phase and the selective extraction is not practicable. This optimization, applied to mixer���settler units, considers the best parameters and operating conditions, as well as the best structure or process flow-sheet. Global process optimization is performed for a specific flow-sheet and a comparison of Pareto curves for different flow-sheets is made. The positive weight sum approach linked to the sequential quadratic programming method is used to obtain the Pareto set. In all investigated structures, recovery increases with hold-up, residence time and agitation speed, while the purity has an opposite behaviour. For the same treatment capacity, counter-current arrangements are shown to promote recovery without significant impairment in purity. Recycling the aqueous phase is shown to be irrelevant, but organic recycling with as many stages as economically feasible clearly improves the design criteria and reduces the most efficient organic flow-rate.

Optimization of immunocytochemistry in cytology: comparison of two protocols for fixation and preservation on cytospin and smear preparations

Objective: A new protocol for fixation and slide preservation was evaluated in order to improve the quality of immunocytochemical reactions on cytology slides. Methods: The quality of immunoreactions was evaluated retrospectively on 186 cytology slides (130 direct smears, 56 cytospins) prepared from different cytology samples. Ninety-three of the slides were air dried, stored at -20 ��C and fixed in acetone for 10 minutes (Protocol 1), whereas the other 93 were immediately fixed in methanol at -20 ��C for at least 30 minutes, subsequently protected with polyethylene glycol (PEG) and stored at room temperature (Protocol 2). Immunocytochemical staining, with eight primary antibodies, was performed on a Ventana BenchMark Ultra instrument using an UltraView Universal DAB Detection Kit. The following parameters were evaluated for each immunoreaction: morphology preservation, intensity of specific staining, background and counterstain. The slides were blinded and independently scored by four observers with marks from 0 to 20. Results: The quality of immunoreactions was better on methanol-fixed slides protected with PEG than on air-dried slides stored in the freezer: X�� = 14.44 �� 3.58 versus X�� = 11.02 �� 3.86, respectively (P < 0.001). Conclusion: Immediate fixation of cytology slides in cold methanol with subsequent application of PEG is an easy and straightforward procedure that improves the quality of immunocytochemical reactions and allows the storage of the slides at room temperature.

Economic, environmental and mixed objective functions in non-linear process optimization using simulated annealing and tabu search

Screening of topologies developed by hierarchical heuristic procedures can be carried out by comparing their optimal performance. In this work we will be exploiting mono-objective process optimization using two algorithms, simulated annealing and tabu search, and four different objective functions: two of the net present value type, one of them including environmental costs and two of the global potential impact type. The hydrodealkylation of toluene to produce benzene was used as case study, considering five topologies with different complexities mainly obtained by including or not liquid recycling and heat integration. The performance of the algorithms together with the objective functions was observed, analyzed and discussed from various perspectives: average deviation of results for each algorithm, capacity for producing high purity product, screening of topologies, objective functions robustness in screening of topologies, trade-offs between economic and environmental type objective functions and variability of optimum solutions.

Optimization of QuEChERS procedure coupled to GC-ECD for organochlorine pesticide determination in carrot samples

An optimised version of the Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method for simultaneous determination of 14 organochlorine pesticides in carrots was developed using gas chromatography coupled with electron-capture detector (GC-ECD) and confirmation by gas chromatography tandem mass spectrometry (GC-MS/MS). A citrate-buffered version of QuEChERS was applied for the extraction of the organochlorine pesticides, and for the extract clean-up, primary secondary amine, octadecyl-bonded silica (C18), magnesium sulphate (MgSO4) and graphitized carbon black were used as sorbents. The GC-ECD determination of the target compounds was achieved in less than 20 min. The limits of detection were below the EUmaximum residue limits (MRLs) for carrots, 10���50 ��g kg���1, while the limit of quantification did exceed 10 ��g kg���1 for hexachlorobenzene (HCB). The introduction of a sonication step was shown to improve the recoveries. The overall average recoveries in carrots, at the four tested levels (60, 80, 100 and 140 ��g kg���1), ranged from 66 to 111% with relative standard deviations in the range of 2��� 15 % (n03) for all analytes, with the exception of HCB. The method has been applied to the analysis of 21 carrot samples from different Portuguese regions, and ��-HCH was the pesticide most frequently found, with concentrations oscillating between less than the limit of quantification to 14.6 ��g kg���1. Only one sample had a pesticide residue (��-HCH) above the MRL, 14.6 ��g kg���1. This methodology combines the advantages of both QuEChERS and GC-ECD, producing a very rapid, sensitive and reliable procedure which can be applied in routine analytical laboratories.

Optimization of a microplate-based assay to assess esterase activity in the alga Pseudokirchneriella subcapitata

The present work describes the optimization of a short-term assay, based on the inhibition of the esterase activity of the alga Pseudokirchneriella subcapitata, in a microplate format. The optimization of the staining procedure showed that the incubation of the algal cells with 20 ��molL���1 fluorescein diacetate (FDA) for 40 min allowed discrimination between metabolic active and inactive cells. The shortterm assay was tested using Cu as toxicant. For this purpose, algal cells, in the exponential or stationary phase of growth, were exposed to the heavy metal in growing conditions. After 3 or 6 h, cells were subsequently stained with FDA, using the optimized procedure. For Cu, the 3- and 6-h EC50 values, based on the inhibition of the esterase activity of algal cells in the exponential phase of growth, were 209 and 130 ��g L���1, respectively. P. subcapitata cells, in the stationary phase of growth, displayed higher effective concentration values than those observed in the exponential phase. The 3- and 6-h EC50 values for Cu, for cells in the stationary phase, were 443 and 268 ��gL���1, respectively. This short-term microplate assay showed to be a rapid endpoint for testing toxicity using the alga P. subcapitata. The small volume required, the simplicity of the assay (no washing steps), and the automatic reading of the fluorescence make the assay particularly well suited for the evaluation of the toxicity of a high number of environmental samples.

Convex optimization framework for intermediate deadline assignment in soft and hard real-time distributed systems

It is generally challenging to determine end-to-end delays of applications for maximizing the aggregate system utility subject to timing constraints. Many practical approaches suggest the use of intermediate deadline of tasks in order to control and upper-bound their end-to-end delays. This paper proposes a unified framework for different time-sensitive, global optimization problems, and solves them in a distributed manner using Lagrangian duality. The framework uses global viewpoints to assign intermediate deadlines, taking resource contention among tasks into consideration. For soft real-time tasks, the proposed framework effectively addresses the deadline assignment problem while maximizing the aggregate quality of service. For hard real-time tasks, we show that existing heuristic solutions to the deadline assignment problem can be incorporated into the proposed framework, enriching their mathematical interpretation.