María Inmaculada Paz Andrade

An intelligent system for forest fire risk prediction and fire fighting management in Galicia

Abstract Over the last two decades in southern Europe, more than 10 million hectares of forest have been damaged by fire. Due to the costs and complications of fire-fighting a number of technical developments in the field have been appeared in recent years. This paper describes a system developed for the region of Galicia in NW Spain, one of the regions of Europe most affected by fires. This system fulfills three main aims: it acts as a preventive tool by predicting forest fire risks, it backs up the forest fire monitoring and extinction phase, and it assists in planning the recuperation of the burned areas. The forest fire prediction model is based on a neural network whose output is classified into four symbolic risk categories, obtaining an accuracy of 0.789. The other two main tasks are carried out by a knowledge-based system developed following the CommonKADS methodology. Currently we are working on the trail of the system in a controlled real environment. This will provide results on real behaviour that can be used to fine-tune the system to the point where it is considered suitable for installation in a real application environment.

Molar excess heat capacities and volumes for mixtures of alkanoates with cyclohexane at 25°C

Molar excess volumes VE at 25°C have been determined by vibrating-tube densimetry, as a function of mole fraction x for different series of an alkanoate (H2m+1CmCOOCnH2n+1)+cyclohexane. Three types of alkanoates were investigated, i.e., methanoates (m=0, with n=3 and 4), ethanoates (m=1, with n=2, 3, and 4) and propanoates (m=2, with n=1, 2, and 3). In addition, a Picker flow calorimeter was used to obtain molar excess heat capacities CpE at constant pressure at the same temperature. VE is positive for all systems and rather symmetric, with VE (x=0.5) amounting to almost identical values in a series of mixtures containing an alkanoate isomer of same formula (say C4H8O2, C5H10O2, or C6H12O2). The composition dependence of CpE is rather unusual in that two more or less marked minima are observed for most of the mixtures, especially when the alkanoate is a methanoate or an ethanoate. These results are discussed in terms of possible changes in conformation of both the ester and cyclohexane.

Refractive Indices and Speeds of Sound of Binary Mixtures of N-Octane with 1-Alkanol at the Temperature 298.15 K

Abstract This paper reports experimental values for the refractive index, speed of sound, and isentropic compressibility of binary mixtures of n-octane with (1-butanol, 1-hexanol and 1-octanol) at the temperature of 298.15 K and atmospheric pressure, as a function of mole fraction. From the experimental values, the corresponding derived values were computed (changes of refractive index, changes of speed of sound and changes of isentropic compressibilities) using variable-degree polynomials to fit the data. Also, an attempt was made to correlate the behaviour of these magnitudes to the number of carbon atoms in the 1-alkanol chain.

Thermodynamic studies on the interaction of n-alkyltrimethylammonium bromides with anionic polypeptides in aqueous solution

The enthalpies of interaction of a homologous series of n-alkyltrimethylammonium bromides (C12, C10 and C8 TABs) with poly(L-glutamate) and poly(L-aspartate) in water at 25 °C have been measured over a range of TAB concentrations up to approximately the critical micelle concentrations. The interactions are all endothermic and for the C12 and C10 TABs the enthalpies go through maxima as a function of concentration. The maxima are attributed to the onset of an exothermic contribution arising from the aggregation of polypeptide–TAB complexes in the case of the C12 and C10 TABs, evidence for which comes from the onset of turbidity due to the presence of large particles in the suspensions detectable by photon correlation spectroscopy. For the C12 TAB, enthalpy measurements at pH 3.2 show that the enthalpy is greatly reduced, suggesting that a major contribution to the enthalpy arises from interaction between the carboxylate side chains of the polypeptides and the TAB head group. Binding of the C12 and C10 TABs to the polypeptide has been measured by equilibrium dialysis and has been used to calculate the Gibbs energy of binding per TAB molecule. At low levels of binding, in the approximate range 0 to 0.5 TAB molecules per polypeptide residue, the calorimetric data in combination with the Gibbs energies of binding have been used to estimate the entropic contribution to binding. The entropies of binding are positive for all the systems suggesting dehydration and hydrophobic contributions to the interactions between the TABs and the anionic polypeptides.

Excess Molar Enthalpies of Ternary and Binary Mixtures Containing 2-Methoxy-2-methylpropane, 1-Propanol, and Nonane †

Excess molar enthalpies for the ternary system {x 1 2-methoxy-2-methylpropane (MTBE) + x 2 1-propanol + (1 ― x 1 ― x 2 ) nonane} and the involved binary mixture {x 1-propanol + (1 ― x) nonane} have been measured at the temperature of 298.15 K and atmospheric pressure, over the whole composition range. No experimental excess enthalpy values were found in the currently avaliable literature for the ternary and binary mixtures under study in similar conditions. Values of excess molar enthalpies were measured using a Calvet microcalorimeter. The results were fitted by means of different variable degree polynomials. Smooth representations of the results are presented and used to construct constant excess molar enthalpy contours on Roozeboom diagrams. The group contribution model of the UNIFAC model (in the versions of Larsen et al. and Gmehling et al.) was used to estimate ternary excess enthalpy values. Several empirical expressions for estimating ternary properties from binary results were also tested.

Excess molar volumes of ternary mixtures of 2-butanone or 2-pentanone with 1-chloroctane + n-octane at 25°C

Excess molar volumes at 25°C of the ternary systems 2-butanone + 1 -chlorooctane + octane and 2-pentanone + 1-chlorooctane + octane and of binary mixtures 2-butanone + octane, 2-pentanone + octane, and 1-chlorooctane + octane, were determined using an Anton Paar DMA 60/602 densimeter. All the experimental values were compared with the results obtained by empirical expressions for estimating ternary properties from binary data. Variable degree polynomials were fitted to the results.