Browsing by Author "Baptista, C."
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- Portuguese Hemp Plant as Raw Material for PapermakingPublication . Baptista, C.; Santos, Natércia; Rosa, ManuelThe objectives of this study were the physical and chemical characterization of Portuguese industrial hemp and the assessment of its suitability to produce kraft pulp. A comparison was established with a reference eucalyptus pulp, obtained by the same chemical process. Handmade paper sheets were prepared in the laboratory using hemp pulp, eucalyptus pulp and a blend of both fibres in order to compare final paper properties. The unbleached pulp was produced by batch kraft cooking (NaOH + Na2S) and the evaluation of pulp bleachability was carried out under a D0E0D1E1D2 sequence. The physical properties of laboratory papers prepared with different compositions (100% hemp, 100% eucalyptus, hemp/eucalyptus 50:50) were assessed according to International Standards. Hemp fibres present two fractions, bast and core (33% and 67% of the total stem mass, respectively) with distinct biometric characteristics and cell composition. The hemp plant allowed cooking yield overlapping the wood reference, with lesser uncooked fractions. The pulp exhibited a good bleachability, even better than the reference. Hemp plant allowed a pulp with a higher gain of brightness and lower loss of intrinsic viscosity than eucalyptus. Hemp pulp also showed a better beatability, superiority in tearing resistance and a lower air permeability. The paper sheets obtained with the hemp/ eucalyptus mixture showed interesting properties, which predicts a suitable combination of these two raw materials for papermaking.
- Water quality monitoring in the Paul do Boquilobo Biosphere ReservePublication . Baptista, C.; Santos, LuisThe Paul do Boquilobo is an important wetland ecosystem classified by Unesco as a MAB Biosphere reserve also awarded Ramsar site status, representing one of the most important habitats for the resident nesting colony of Cattle Egret (Bulbucus ibis). Yet owing to its location, it suffers from human induced impacts which include industrial and domestic effluent discharges as well as agricultural land use which have negatively impacted water quality. The current study reports the results obtained from the introductory monitoring programme of surface water quality in the Nature Reserve to emphasize the detrimental impact of the anthropogenic activities in the water quality of such an important ecosystem. The study involved physicochemical and biotic variables, microbial parameters and biological indicators. Results after 3 years of monitoring bring to evidence a poor water quality further impaired by seasonal patterns. Statistical analysis of data attributed water quality variation to 3 main parameters – pH, dissolved oxygen and nitrates, indicating heavy contamination loads from both organic and agricultural sources. Seasonality plays a role in water flow and climatic conditions, where sampling sites presented variable water quality data, suggesting a depurative function of the wetland.