Optimal location of gas supply units in natural gas system network

Natural gas industry has been confronted with big challenges: great growth in demand, investments on new GSUs – gas supply units, and efficient technical system management. The right number of GSUs, their best location on networks and the optimal allocation to loads is a decision problem that can be formulated as a combinatorial programming problem, with the objective of minimizing system expenses. Our emphasis is on the formulation, interpretation and development of a solution algorithm that will analyze the trade-off between infrastructure investment expenditure and operating system costs. The location model was applied to a 12 node natural gas network, and its effectiveness was tested in five different operating scenarios.

Optimization model for medium term natural gas commitment

In this paper we study the optimal natural gas commitment for a known demand scenario. This study implies the best location of GSUs to supply all demands and the optimal allocation from sources to gas loads, through an appropriate transportation mode, in order to minimize total system costs. Our emphasis is on the formulation and use of a suitable optimization model, reflecting real-world operations and the constraints of natural gas systems. The mathematical model is based on a Lagrangean heuristic, using the Lagrangean relaxation, an efficient approach to solve the problem. Computational results are presented for Iberian and American natural gas systems, geographically organized in 65 and 88 load nodes, respectively. The location model results, supported by the computational application GasView, show the optimal location and allocation solution, system total costs and suggest a suitable gas transportation mode, presented in both numerical and graphic supports.

Natural gas system operation: lagrangean optimization techniques

To comply with natural gas demand growth patterns and Europe´s import dependency, the gas industry needs to organize an efficient upstream infrastructure. The best location of Gas Supply Units – GSUs and the alternative transportation mode – by phisical or virtual pipelines, are the key of a successful industry. In this work we study the optimal location of GSUs, as well as determining the most efficient allocation from gas loads to sources, selecting the best transportation mode, observing specific technical restrictions and minimizing system total costs. For the location of GSUs on system we use the P-median problem, for assigning gas demands nodes to source facilities we use the classical transportation problem. The developed model is an optimisation-based approach, based on a Lagrangean heuristic, using Lagrangean relaxation for P-median problems – Simple Lagrangean Heuristic. The solution of this heuristic can be improved by adding a local search procedure - the Lagrangean Reallocation Heuristic. These two heuristics, Simple Lagrangean and Lagrangean Reallocation, were tested on a realistic network - the primary Iberian natural gas network, organized with 65 nodes, connected by physical and virtual pipelines. Computational results are presented for both approaches, showing the location gas sources and allocation loads arrangement, system total costs and gas transportation mode.

Exposure to particles in Portuguese swine production

Several studies have shown that human exposures to airbome dust and microorganisms, such as bacteria and fungi, can cause respiratory diseases. Agricultural workers have been found to be at high risk of exposures to airborne particles. From a human health perspective dust exposure in pig farming is the most important risk because of the large number of workers needed in pig production and the increasing number of working hours inside enclosed buildings. In the pig buildings, particulate matters like dust play a role in not only deteriorating indoor air quality but also can cause an adverse health effect on workers. Generally, dust is recognized to adsorb and transport odorous compounds and biological agents. The aim of this study was to determine particles contamination in 7 swine farms located in Lisbon district, Portugal.

Fungi, MVOCs and dust exposure assessment in poultry production

Agricultural workers especially poultry farmers, are at increased risk of occupational respiratory diseases. In poultry production besides fungi microbial volatile organic compounds (MVOCs) are also present due to compounds released during fungal metabolism. Dust is also one of the risk factors present in animal housing and is comprised by poultry residues, fungi and feathers. A study was developed aiming to assess occupational exposure to fungi, MVOCs and dust in seven poultry units located in Portugal.

Execução da Augi 42, Casal do Sapo, Sesimbra

O estágio desenvolvido na empresa de construção Manuel da Graça Peixito, incidiu sobre Direcção e Gestão de Obra na execução de um projecto de reconversão urbanística a aplicar na AUGI 42 localizada no Casal do Sapo em Sesimbra. As áreas urbanas de génese ilegal, denominadas de AUGI, surgiram no inicio da década de 60, como um fenómeno que surgiu de forma a colmatar a carência no parque habitacional das periferias das grandes áreas metropolitanas do território nacional. O ambiente urbano gerado pela existência das AUGI, muitas vezes de proporções de grande dimensão, evidencia inúmeras carências e problemas a níveis sociais, económicos, urbanísticos e legais. A gestão de obra é uma actividade essencial na execução da obra e no planeamento de todas as tarefas a realizar com o melhor tratamento económico e financeiro. A direcção de obra tem como principais funções a selecção de recursos humanos, escolha e montagem dos órgãos de apoio logístico, a aquisição atempada e negociação de materiais. O Gestor e Director de Obra é colocado num ciclo operacional de optimização de recursos e eficiências, em que as duas funções, gestão e direcção de obra, são complementares e a abordagem do contexto interactivo do controlo da obra, em termos da produção, da gestão económica e financeira, da gestão do tempo, do cumprimento das normas de saúde e segurança no trabalho e no assegurar da qualidade, são claramente identificadas, enquanto veículo indispensável do cumprimento do contrato de empreitada. O processo de reconversão urbanística aplicado na AUGI 42 teve como estrutura de proposta a seguinte base: primeiro na recolha de dados relativo à AUGI 42 e na definição de um planeamento do faseamento numa estratégia de execução da empreitada; segundo na constituição e caracterização da execução de variadas infra-estruturas (rede de drenagem de esgotos domésticos e pluviais, rede de abastecimento de águas, rede de telecomunicações, rede eléctrica, rede de gás, rede viária e arranjos de espaços exteriores). Este processo e consequente proposta surgem como um contributo fundamental na melhoria da qualidade de vida das populações, como também da funcionalidade do sistema urbano que compõe as AUGI.

Cellular hypomethylation is associated with impaired nitric oxide production by cultured human endothelial cells

Hyperhomocysteinemia (HHcy) is a risk factor for vascular disease, but the underlying mechanisms remain incompletely defined. Reduced bioavailability of nitric oxide (NO) is a principal manifestation of underlying endothelial dysfunction, which is an initial event in vascular disease. Inhibition of cellular methylation reactions by S-adenosylhomocysteine (AdoHcy), which accumulates during HHcy, has been suggested to contribute to vascular dysfunction. However, thus far, the effect of intracellular AdoHcy accumulation on NO bioavailability has not yet been fully substantiated by experimental evidence. The present study was carried out to evaluate whether disturbances in cellular methylation status affect NO production by cultured human endothelial cells. Here, we show that a hypomethylating environment, induced by the accumulation of AdoHcy, impairs NO production. Consistent with this finding, we observed decreased eNOS expression and activity, but, by contrast, enhanced NOS3 transcription. Taken together, our data support the existence of regulatory post-transcriptional mechanisms modulated by cellular methylation potential leading to impaired NO production by cultured human endothelial cells. As such, our conclusions may have implications for the HHcy-mediated reductions in NO bioavailability and endothelial dysfunction.

Mental health and psychiatry research in Brazil: scientific production from 1999 to 2003

OBJECTIVE: To assess the extent of mental health scientific production in Brazil from 1999 to 2003, and to identify the nature of the publications generated, their sources of finance and the ways of publicly disseminating the research findings. METHODS: Searches for publications were conducted in the Medline and PsychInfo databases for the period 1999-2003. A semi-structured questionnaire developed by an international team was applied to 626 mental health researchers, covering each interviewee's educational background, research experience, access to funding sources, public impact and research priorities. The sample was composed by 626 mental health researchers identified from 792 publications indexed on Medline and PsychInfo databases for the period above, and from a list of reviewers of Revista Brasileira de Psiquiatria. RESULTS: In Brazil, 792 publications were produced by 525 authors between 1999 and 2003 (441 indexed in Medline and 398 in the ISI database). The main topics were: depression (29.1%), substance misuse (14.6%), psychoses (10%), childhood disorders (7%) and dementia (6.7%). Among the 626 Brazilian mental health researchers, 329 answered the questionnaire. CONCLUSIONS: There were steadily increasing numbers of Brazilian articles on mental health published in foreign journals from 1999 to 2003: the number of articles in Medline tripled and it doubled in the ISI database. The content of these articles corresponded to the priorities within mental health, but there is a need for better interlinking between researchers and mental health policymakers.

Production of hydroxamic acids by immobilized Pseudomonas aeruginosa cells Kinetic analysis in reverse micelles

Intact cells from Pseudomonas aeruginosa strain L10 containing amidase were used as biocatalysts both free and immobilized in a reverse micellar system. The apparent kinetic constants for the transamidation reaction in hydroxamic acids synthesis, were determined using substrates such as aliphatic, amino acid and aromatic amides and esters, in both media. In reverse micelles, K-m values decreased 2-7 fold relatively to the free biocatalyst using as substrates acetamide, acrylamide, propionamide and glycinamide ethyl ester. We have concluded that overall the affinity of the biocatalyst to each substrate increases when reactions are performed in the reversed micellar system as opposed to the buffer system. The immobilized biocatalyst in general, exhibits higher stability and faster rates of reactions at lower substrates concentration relatively to the free form, which is advantageous. Additionally, the immobilization revealed to be suitable for obtaining the highest yields of hydroxamic acids derivatives, in some cases higher than 80%. (C) 2013 Elsevier B.V. All rights reserved.

Biodiesel production from waste frying oils over lime catalysts

Biodiesel production from semi-refined oils (SRO) and waste frying oils (WFO) was studied using commercial CaO as heterogeneous catalyst. The methanolysis tests were carried out in mild reaction conditions (62 A degrees C, atmospheric pressure). With such conditions, SRO (soybean and rapeseed) allowed to produce a biodiesel containing 97-98 % of methyl esters (FAME), whereas WFO only provided 86-87 % of FAME. The lower FAME yield for WFO oil is ascribable to the partial neutralization of the catalyst by free fatty acids. Also, soaps formation from the WFO oil reduced the weight yield of the oil phase (containing FAME) obtained and increased the MONG content of the glycerin phase. The catalysts stability tests showed high stability even when WFO oil was processed. Catalytic tests performed with blends of WFO/semi-refined oils showed blending as a good strategy to process low value raw oils with minor decay of the catalyst performance. Both WFO and semi-refined oils showed S-shape kinetics curves thus discarding significant differences of the reaction mechanisms.

Microalgae production for commercial purposes in the Azores

IBBA Strategic Planning - Workshop III, Plant Biotechnology Ponta Delgada, 25 Janeiro, 2011.

Astaxanthin production using Photobioreactors, investigation and scale up and an integrated solution for eutrophic lakes

TRANSCREA, Convertir la investigación y el conocimiento en innovación, propiedad intelectual e industrial. Terceira, 16 e 17 Fevereiro, 2011.

Eficiência energética e a queima de combustíveis limpos

Mestrado em Engenharia Química

Analysis of six fungicides and one acaricide in still and fortified wines using solid-phase microextraction-gas chromatography/tandem mass spectrometry

A multiresidue gas chromatographic method for the determination of six fungicides (captan, chlorthalonil, folpet, iprodione, procymidone and vinclozolin) and one acaricide (dicofol) in still and fortified wines was developed. Solid-phase microextraction (SPME) was chosen for the extraction of the compounds from the studied matrices and tandem mass spectrometry (MS/MS) detection was used. The extraction consists in a solvent free and automated procedure and the detection is highly sensitive and selective. Good linearity was obtained with correlation coefficients of regression (R2) > 0.99 for all the compounds. Satisfactory results of repeatability and intermediate precision were obtained for most of the analytes (RSD < 20%). Recoveries from spiked wine ranged from 80.1% to 112.0%. Limits of quantification (LOQs) were considerably below the proposedmaximumresidue limits (MRLs) for these compounds in grapes and below the suggested limits for wine (MRLs/10), with the exception of captan.

Occupational exposure to Aflatoxin B1 in swine production and possible contamination sources

Although the adverse health consequences of ingestion of food contaminated with aflatoxin B1 (AFB1) are known, relatively few studies are available on the adverse effects of exposure in occupational settings. Taking this into consideration, our study was developed aiming to elucidate the possible effects of occupational exposure to AFB1 in Portuguese swine production facilities using a specific biomarker to assess exposure to AFB1. In total, 28 workers participated in this study, providing blood samples, and a control group (n  = 30) was composed of subjects without any type of agricultural activity. Fungal contamination was also studied by conventional methods through air, surfaces, and new and used floor coverage. Twenty-one workers (75%) showed detectable levels of AFB1 with values ranging from <1 ng/ml to 8.94 ng/ml and with a mean value of 1.91 ± 1.68 ng/ml. In the control group, the AFB1 values were all below 1 ng/ml. Twelve different Aspergillus species were identified. Aspergillus versicolor presented the highest airborne spore counts (3210 CFU/m3) and was also detected in higher values in surfaces (>300 CFU/cm2). Data indicate that exposure to AFB1 occurs in swine barns, and this site serves as a contamination source in an occupational setting.