Fernando J. P. Caetano

Viscosity Measurements of Liquid Toluene at Low Temperatures Using a Dual Vibrating-Wire Technique

A recently developed dual vibrating-wire technique has been used to perform viscosity measurements of liquid toluene in the temperature range 213 K≤T≤298 K, and at pressures up to approximately 20 MPa. The results were obtained by operating the vibrating-wire sensor in both forced and free decay modes. The estimated precision of the viscosity measurements, in either mode of operation, is ±0.5%, for temperatures above or equal to 273 K, increasing with decreasing temperature up to ±1% at 213 K. The corresponding overall uncertainty is estimated to be within ±1% and ±1.5%, respectively.

Volumetric Properties and Spectroscopic Studies of Pyridine or Nicotine Solutions in Liquid Polyethylene Glycols

Densities and molar excess volumes of the solutions of pyridine or nicotine in liquid polyethylene glycol, PEG200 and PEG400, have been determined at several temperatures. The experimental molar excess volumes are negative, thus indicating strong attractive interactions between the components, as could be expected considering their highly polar nature and good hydrogen bond abilities. For the pyridine systems, this negativity is slightly increased as the temperature rises, while the opposite tendency is observed for the nicotine mixtures. When pyridine and nicotine solutions are compared, the former-particularly those with PEG400-exhibit substantially more negative molar excess volumes than the latter. The effect of the polymer chain length on the results for the nicotine solutions is almost negligible. However, this is not the case when pyridine is one of the components: a longer chain induced considerably higher compression on mixing. The Fourier-transform infrared analysis allowed interpretation of the negative experimental molar excess volumes in terms of specific inter- and intramolecular interactions.

Impedance spectroscopy of a vibrating wire for viscosity measurements

Many routine viscosity measurement systems suffer from low accuracy and some are also operator dependant which creates repeatability problems. This paper describes the ongoing developments of a viscosity measurement system based on a vibrating wire cell. The proposed improvements include the simultaneous fitting of the magnitude and phase of the measured impedance and the test of different equivalent impedance circuits. Since the fitting function has a high number of search variables and contains many local minima, a hybrid method involving genetic algorithms as well as a traditional search algorithm is used. The system is tested with liquid diisodecyl phthalate (DIDP) and the viscosity results are compared to reference values available in the literature. A new equivalent impedance circuit is also suggested as one of the possible circuits to model the cell behavior in the future, when used with ionic liquids.

Climate Change and Integrated Coastal Management: Risk Perception and Vulnerability in the Luanda Municipality (Angola)

Climate change has imposed significant changes in the structure and natural dynamics of coastal ecosystems, compromising their resilience capabilities. The socio-environmental vulnerability in many coastal areas is aggravated by the inadequate articulation of an integrated territorial management and policies and plans to adapt to climate change. This work was carried out in the municipality of Luanda where erosion, floods and mass movements are an increasingly worrying reality. The research methodology for this study was based on questionnaire surveys and semi-structured interviews, with a focus on qualitative aspects, applied to policy makers, population and NGOs. The results indicate a lack of active participation of citizens, training and taking initiatives in environmental policies and integrated management of the coastal zone, and a lack of environmental information and integrated coordination of institutions with environmental responsibility.

Towards Climate Change Awareness Through Distance Learning—Are Young Portuguese and Brazilian University Students Vigilant?

Although distance learning and e-learning are currently acknowledged as important training tools for higher education institutions, they are seldom used as a way of disseminating environmental sustainability, climate change and its implications. The work presented here is the result of a teamwork between two universities, one from Brazil and the other from Portugal, which joined efforts to promote an interdisciplinary massive open on-line course associated with the environmental sustainability. We have inquired young university students from these two countries in order to understand which are their main conceptions and ideas about the climate changes as well as proposals they have for its mitigation. From these dialogs, we observed that, irrespectively of the geographical distance/location, those young students, share similar concerns, conceptions and proposals but it is also noticeable a clear lack of scientific knowledge when discussing these topics. This is an important starting point for the creation of a set of learning resources accessible to different audiences and with different and diverse backgrounds that can stimulate the interest on scientific knowledge. In this context it is our believe that eLearning and distance education supported by the information technologies can efficiently and effectively contribute for a well-supported knowledge on environmental sustainability, namely climate changes its causes and effects.

Extraction of alkaloids from Lupinus albus sp. using compressed carbon dioxide

The extraction of lupanine from lupine (Lupinus albus sp.) flour using liquid carbon dioxide (8 MPa, 313 K) and supercritical carbon dioxide (10 MPa, 15 MPa and 20 MPa at 298 K and 313 K) was investigated. Small quantities of lupanine were obtained at the studied conditions, being the percentages of lupanine related to the total mass of extract between 0.02 % and 1.13 % at 10 MPa and 298 K, and 20 MPa and 313 K, respectively.