Smart macroporous structures for the purification of viral particles

Dissertação para obtenção do Grau de Mestre em Engenharia Química e Bioquímica

Optimization of the electrodialytic phosphorus recovery from sewage sludge ash

Phosphorus (P) is becoming a scarce element due to the decreasing availability of primary sources. Therefore, recover P from secondary sources, e.g. waste streams, have become extremely important. Sewage sludge ash (SSA) is a reliable secondary source of P. The use of SSAs as a direct fertilizer has very restricted legislation due to the presence of inorganic contaminants. Furthermore, the P present in SSAs is not in a plant-available form. The electrodialytic (ED) process is one of the methods under development to recover P and simultaneously remove heavy metals. The present work aimed to optimize the P recovery through a 2 compartment electrodialytic cell. The research was divided in three independent phases. In the first phase, ED experiments were carried out for two SSAs from different seasons, varying the duration of the ED process (2, 4, 6 and 9 days). During the ED treatment the SSA was suspended in distilled water in the anolyte, which was separated from the catholyte by a cation exchange membrane. From both ashes 90% of P was successfully extracted after 6 days of treatment. Regarding the heavy metals removal, one of the SSAs had a better removal than the other. Therefore, it was possible to conclude that SSAs from different seasons can be submitted to ED process under the same parameters. In the second phase, the two SSAs were exposed to humidity and air prior to ED, in order to carbonate them. Although this procedure was not successful, ED experiments were carried out varying the duration of the treatment (2 and 6 days) and the period of air exposure that SSAs were submitted to (7, 14 and 30 days). After 6 days of treatment and 30 days of air exposure, 90% of phosphorus was successfully extracted from both ashes. No differences were identified between carbonated and non-carbonated SSAs. Thus, SSAs that were exposed to the air and humidity, e.g. SSAs stored for 30 days in an open deposit, can be treated under the same parameters as the SSAs directly collected from the incineration process. In the third phase, ED experiments were carried out during 6 days varying the stirring time (0, 1, 2 and 4 h/day) in order to investigate if energy can be saved on the stirring process. After 6 days of treatment and 4 h/day stirring, 80% and 90% of P was successfully extracted from SSA-A and SSA-B, respectively. This value is very similar to the one obtained for 6 days of treatment stirring 24 h/day.

Removal of organic contaminants from wastewater using the electrodialytic process

Pharmaceuticals and personal care products (PPCPs) are widely used on a daily basis. After their usage they reach the wastewater treatment plants (WWTPs). These compounds have different physico-chemical characteristics, which makes them difficult to completely remove in the WWTPs, througth conventional treatments. Currently, there is no legislation regarding PPCPs thresholds in effluent discharge. But, even at vestigial concentrations, these compounds enclose environmental risks due to, e.g., endocrine disruption potential. There is a need of alternative techniques for their removal in WWTPs. The main goal of this work was to assess the use of electrodialytic (ED) process to remove PPCPs from the effluent to be discharged. A two-compartment ED cell was used testing (i) the effluent position in the cell (anode and cathode compartment); (ii) the use of anion (AEM) and cation exchange membrane (CEM); (iii) the treatment period (6, 12 and 24 hours); (iv) effluent recirculation and current steps; (v) the feasibility of sequential treatments. Phosphorus (P) removal from effluent and energetic costs associated to the process were also evaluated. Five PPCPs were studied – caffeine (CAF), bisphenol A (BPA), 17 β-estradiol (E2), ethinyl estradiol (EE2) and oxybenzone (MBPh). The ED process showed to be effective in the removal when effluent is in the anode compartment. Oxidation is suggested to be the main removal process, which was between 88 and 96%, for all the compounds, in 6 hours. Nevertheless, the presence of intermediates and/or by-products was also observed in some cases. Effluent recirculation should have a retention time in the ED cell big enough to promote removal whereas the current steps (effluent in anode compartment) slightly increased removal efficiencies (higher than 80% for all PPCPs). The sequential set of ED treatment (effluent in anode compartment) showed to be effective during both periods with a removal percentage between 80 and 95% and 73 to 88% in the case of AEM and CEM, respectively. Again, the main removal process is strongly suggested to be oxidation in the anode compartment. However, there was an increase of BOD5 and COD, which might be explained by effluent spiking, these parameters limiting the effluent discharge. From these treatments, the use of AEM, enhanced the P removal from effluent to minimize risk of eutrophication. Energetic costs of the best set-up (6 hours) are approximately 0,8€/m3 of wastewater, a value considered low, attending to the prices of other treatment processes.

The quest for a balanced manpower capacity: different flexibility strategies examined

To cope with permanent fluctuations in demand, organizations are challenged to organize their manpower capacity in a flexible way. Different strategies of manpower planning are being used for this purpose. Using data from the 2002 Panel Survey of Organisations Flanders, we first verify to what extent temporal, contractual and functional flexibility strategies are applied in Flemish organizations. Subsequently, logistic regression is used to analyse the link between these flexible work strategies and a ‘fitting manpower capacity’. While the results show a negative association between the use of temporal or contractual flexibility measures and a balanced manpower capacity, functional flexibility seems to be positively related. The different logics in which numerical and functional flexibility proceed can be labeled as ‘curative’ versus ‘preventive’ strategies of flexibility. Further analyses discern between various interpretations of functional flexibility and assess whether different team types make a contribution to a fitting manpower capacity.

A lightweight distributed super peer election algorithm for unstructured dynamic P2P systems

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia Electrotécnica e de Computadores

Factores que influenciam a actividade física na vida diária dos doentes com doença pulmonar obstrutiva crónica

RESUMO: A monitorização da actividade física diária nos doentes com Doença Pulmonar Obstrutiva Crónica (DPOC) tem sido alvo de grande interesse nos últimos tempos. No entanto, ainda nenhum estudo reuniu o conjunto de factores – grau de obstrução, hiperinsuflação pulmonar, alteração das trocas gasosas, dispneia, dessaturação de oxigénio, capacidade de exercício, ansiedade e depressão – que podem afectar a sua realização, nem os correlacionou com os dados obtidos com o pedómetro e que reflectem o que cada doente realmente faz no seu dia-adia. O presente estudo teve como objectivo principal identificar os factores que influenciam a actividade física na vida diária dos doentes com DPOC. Estudaram-se 55 doentes do sexo masculino com idade média de 67 anos e um FEV1 médio de 50,8% do previsto, com DPOC moderada a muito grave (estadios II a IV), de entre os utentes do Laboratório de Fisiopatologia Respiratória do Centro Hospitalar de Torres Vedras. Avaliaram-se os parâmetros da escala de dispneia modificada do Medical Research Council (MMRC), escala London Chest Activity of Daily Living (LCADL), escala de Ansiedade e Depressão Hospitalar (HADS), índice BODE, estudo funcional respiratório em repouso, teste de marcha de seis minutos e o número de passos por dia utilizando um pedómetro por um período de três dias. Observou-se que os doentes deram em média 4972 passos por dia e apresentaram uma cotação total média de 17,7 na LCADL, tendo existido diferenças estatisticamente significativas em função da gravidade da doença, sendo que os doentes mais graves são os que em média andam menos no seu dia-a-dia e apresentam maior limitação na realização das actividades de vida diária. O número de passos por dia apresentou correlações significativas com as variáveis idade, dispneia, depressão, hiperinsuflação monar, gravidade de obstrução (FEV1), trocas gasosas (DLCO), saturação arterial de oxigénio mínima e correlação mais forte com a distância percorrida no TM6m. Este estudo permitiu identificar que os factores determinantes da actividade física na vida diária de doentes com DPOC nos estadios II a IV, foram a dispneia e a distância percorrida no TM6m. Além disso, estes doentes constituem um grupo sedentário, particularmente a partir do estadio III, com níveis de actividade física diária baixos.-----------ABSTRACT There has been an increased interest in monitoring the daily physical activity in patients with Chronic Obstructive Pulmonary Disease (COPD). However, no specific study has been realized so far that has put the different factors which can affect the results obtained altogether, (such as the degree of obstruction, pulmonary hyperinflation, abnormal gas exchange, dyspnea, oxygen desaturation, exercise capacity, anxiety and depression) or correlated with data obtained from the pedometer, which reflect each patient actual activity in their daily life. This study aimed to identify the main factors that influence physical activity in daily life of patients with COPD. The scope of this study was 55 male patients with an average age of 67 years old and an average FEV1 of 50.8% predicted, with moderate to severe COPD (stages II to IV), among patients from the Respiratory Pathophysiology Laboratory of the Centro Hospitalar de Torres Vedras. Were evaluated the parameters of the modified Medical Research Council dyspnea scale (MMRC), London Chest Activity of Daily Living scale (LCADL), Hospital Anxiety and Depression scale (HADS), BODE index, pulmonary function test at rest, six minute walk test (6MWT) and the number of steps per day using a pedometer for a period of three days. It was observed that patients have walked an average of 4972 steps per day and had a total score of 17.7 at LCADL, and statistically significant differences were stated depending on the severity of the disease. Whereas patients with a more severe degree of the disease have walked least in their daily life and show greater restraint in carrying out activities of daily living. The number of steps per day showed significant correlations with age, dyspnea, depression, lung hyperinflation, severity of obstruction (FEV1), gas exchange (DLCO), minimum arterial oxygen saturation and stronger correlation with distance walked on 6MWT. This study shows that the crucial factors of physical activity in daily life of COPD patients at stages II to IV were dyspnea and distance on 6MWT. Moreover, these patients constitute a sedentary group, particularly from the stage III, with lower levels of daily physical activity.

Modelling and optimization of the ion exchange membrane bioreactor for removal of anionic pollutants from drinking water streams

Dissertação para obtenção do Grau de Doutor em Engenharia Química, especialidade de Engenharia Bioquímica

GIS capacity building for risk management to help developing countries:Case of climate change problem in Amhara rural region (Ethiopia)

Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.

Revealing fungal activity in the presence of ionic liquids

Dissertation presented to obtain the Ph.D degree in Biochemistry

Behavior monitoring and behavioral exchange: an approach from geospatial technologies involving gamification techniques

Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.

The impact of sizeof the firm and exchange rate in the export propensity of domestic and foreign owned firms in a developing country: A study of the Brazilian exporters

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics

How differently do our non-large companies listed on the Portuguese Stock Exchange perform?

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Economics from the NOVA – School of Business and Economics

The social stock exchange: A quantitative exploration

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Economics from the NOVA – School of Business and Economics

Coherent structures in open channel flows with bed load transport over an hydraulically rough bed

Dissertação para obtenção do Grau de Mestre em Engenharia Civil – Perfil de Estruturas

Safe reuse of treated urban wastewater in Praia, Cape Verde: a case study

Dissertação para a obtenção do Grau de Mestre em Engenharia e Gestão da Água