Browsing by Issue Date, starting with "2021-02-11"
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- Water quality of the Ria Formosa at the vicinity of almargem urban wastewater treatment plant and shellfish bedsPublication . Silva, Diana Patrícia; Cravo, AlexandraCoastal lagoons are very productive and economically important ecosystems that suffer several anthropogenic pressures, including from urban wastewater treatment plants (UWWTP) discharges. This last pressure can induce nutrient enrichment and development of primary producers (toxic or not), microbiological contamination of the water or even eutrophication that ultimately will have impact on the organisms living nearby and on their salubrity. Ria Formosa lagoon is a coastal lagoon on the Portuguese south coast responsible for over 90% of the Portuguese shellfish production, however along its extension it suffers influence from several UWWTP discharging in this system, some of them in in the vicinity of the production areas. Since in Tavira there is an important area of shellfish production close to the Gilão estuary it is important to determine the impact of the Almargem UWWTP upon the water quality of the receiving waters and to evaluate if there is any influence of it on the shell production area. The main goals of this work were: i) to determine the spatial extent of the influence of the Almargem UWWTP along the gradient of dispersal of the effluents in the receiving waters, potential impact on the bivalves production area, and the compliance of data with the applicable legislation; ii) to determine the dilution effect within the study area associated with the daily tidal cycles; iii) to determine the effect of different tidal ranges upon the water quality; iv) to determine the seasonal influence of the sewage discharge impact upon the water quality; v) to assess the temporal evolution of the chemical and microbiologic contamination of the water quality in the study area and vi) to calculate a trophic index (TRIX) in the study area, defining a baseline for Almargem UWWTP. The results showed that the Almargem UWWTP clearly influence the water characteristics till 750 m downstream from the UWWTP discharge. In August and February the E. coli concentration was above the limit imposed for the discharge license, both by increased anthropogenic pressure and land runoff after a rainfall event, respectively. The TRIX index varied between eutrophic and oligotrophic conditions, with a lower water quality upstream in the Almargem channel until 1000 m during the summer months. The highest impact on the water quality was registered during low water of neap tides, associated with a higher residence time. The tidal effect and the water renewal are able to decrease contamination, helping to the improve the water quality as observed at 1750 m, considered the reference station and in consequence caused no impact over the shellfish production area. In this area the microbiological contamination recorded suggest that there were external sources at the Gilão low estuary. However, for most of the sampling period, the salubrity of bivalves controlled by IPMA was of class B that can be harvested and sent to depuration, not but negatively affect their production.
- Estágio na Região de Turismo do Algarve: análise dos indicadores e das métricas do website promocional e das redes sociaisPublication . Vieira, Laura Marie Lourenço; Santos, Margarida C.; Miguel, SusanaCom o intuito de concluir o mestrado em Gestão de Marketing da Faculdade de Economia, da Universidade do Algarve, foi realizado um estágio curricular na Região de Turismo do Algarve. O relatório de estágio é o trabalho final ao qual irá resultar na obtenção do grau de mestre na instituição de ensino referida. O presente trabalho pretende atingir objetivos estabelecidos para o estágio e para o estudo empírico. Os objetivos do estágio são: colaborar numa entidade onde fosse possível conciliar as duas áreas de formação, o turismo e o marketing; desenvolver competências de marketing digital; iniciar o desenvolvimento do conhecimento do marketing em termos profissionais e aplicar os conhecimentos teóricos no contexto real das organizações. Os objetivos do estudo empírico são: analisar os indicadores e as métricas do website promocional da organização e das redes sociais; observar o desempenho das plataformas digitais de acordo com os consumidores e os seus comportamentos online nessas mesmas plataformas; e entender que tipo de conteúdos apresentam um maior engagement por parte dos consumidores. No presente relatório é feita uma apresentação da organização que acolheu a estagiária assim como das funções desempenhadas pela mesma. A temática e a área em que incidiu o estágio, o marketing digital, será abordada na revisão da literatura que teve como base referências bibliográficas, o que permitiu aprofundar os conhecimentos nesta área. Para iniciar será feita a introdução ao relatório de forma a contextualizar o mesmo. De seguida é apresentada a organização e é feita a caracterização do estágio curricular e das atividades realizadas dentro do departamento de Marketing. O enquadramento teórico na revisão da literatura aborda as temáticas relacionadas com o estágio e o estudo realizado, sobretudo o marketing digital, os social media e o digital analytics. Por fim, encontra-se a metodologia de investigação e o estudo empírico realizado sobre os canais digitais da organização, o website promocional e as redes sociais Facebook e Instagram. Com a realização do estudo empírico às plataformas digitais da entidade acolhedora foi possível compreender a forma como as mesmas estavam a ser recebidas pelos consumidores. A realização do estágio curricular e a elaboração do respetivo relatório mostraram-se ser a abordagem mais apropriada para o trabalho final do mestrado, no sentido em que permitiram adquirir experiência em contexto profissional e aprofundar temáticas pouco abordadas no plano curricular do mestrado.
- Cellulose dissolution and gelation in alkaline-based solventsPublication . Pereira, Ana Catarina Dias; Romano, Anabela; Olsson, UlfIssues of environmental concern and sustainability are pressing for an efficient and growing use of biomass and naturally occurring polymers to create new materials and sustainable opportunities and solutions. An effective utilization and sourcing of cellulose, as the world’s most abundant renewable material, not only reduces the consumption of our limited fossil resources but also protects the environment. To produce cellulose based materials for various applications, cellulose requires dissolution at some point, and this task can be challenging. The traditional methods of dissolution have some limitations: some require high investments others create occupational health and environmental issues. Therefore, it is important to develop inexpensive and environmentally “friendly” alternatives to these solvents. With this purpose in mind, the main goal of this work was to study alkaline-based solvents regarding their interaction and effect on cellulose dissolution, while accessing the aggregation and gelation phenomena. This work was divided in two parts: The first part focus on cellulose dissolution and gelation in sodium hydroxide studied by time resolved rheology, turbidimetry and wide-angle X-ray scattering. The kinetics of gelation are observed to be strongly temperature dependent, changing from several hours down to few seconds when the temperature is increased from 25 to 30 ºC. The obtained gels are irreversibly formed. Wide angle X-ray scattering data reveals the formation of ordered domains, as the sample gels, and it is suggested the gelation is due to the crystallization and precipitation of cellulose. This strongly indicates that the gelation phenomena can be understood as cellulose precipitation/crystallization where an effectively cross-linked network and gelation results from that cellulose chains may participate in more than one crystallite. This part of the work resulted in a published article that can be found in Appendix B. The second part focussed on the molecular self-diffusion coefficients measured in cellulose solutions dissolved in 30 wt. %, 55 wt. % and mixtures of 40 wt. % TBAH (aq.) and DMSO at different ratios, using pulsed field gradient stimulated echo NMR. The results show that dissolution efficiency of TBAH (aq.) is not compromised significantly even when high amounts of the organic co-solvent (DMSO) are present, in agreement with previous studies. Compared with the standard TBAH (aq.) solvent - 55 wt. % TBAH (aq.), the systems with DMSO presented in this work are highly advantageous since they use much less TBAH (substituted by DMSO) making the dissolution process much less expensive and possibly viable for large scale applications. Additionally, the molecular self-diffusion coefficients obtained highlight that TBAH can “bind” to cellulose within an interval of 0.5 TBA+ to 2.3 TBA+ per anhydroglucose unit depending on the TBAH amount in solution. The main driving force for this binding may be the favourable electrostatic interactions between the TBA+ cations and the deprotonated hydroxyl groups on the cellulose molecules coupled with hydrophobic interactions. Moreover, temperature seems to not have a significant effect on the relative diffusion coefficient of the different species either in the presence or absence of DMSO in the mixture, at least in the temperature range studied.