In fire-prone areas, like the Mediterranean, land abandonment and forestation may interact with fire to alter landscape properties and eventually fire hazard and occurrence. However, the spatial interactions among the two processes (land-use/land cover change [LULC] and fire) are poorly known. Here, we analysed the relative effect of LULC change and fire on the landscape structure of an area of Central Spain frequently affected by fire. A series of Landsat MSS images from 1975 to 1990 was analysed to quantify annual changes in LULC, map fire perimeters and evaluate the changes in landscape properties. The temporal dynamics were analysed by annually computing the fraction occupied by each LULC type and landscape structural properties (number, size, shape and arrangement of patches) that might play a role in fire propagation. All of these were calculated separately for the unburned or the burned areas during the study period, as well as for the entire area. At the whole landscape level, or in the unburned area, LULC changes were small, yet the two more flammable LULC types tended to increase, and the landscape tended to become more homogeneous. In the burned area, the area covered by pine woodlands tended to decrease, and that covered by shrublands to increase. Burned areas turned into shrublands only five years after fire. Landscape indices indicative of reduced fragmentation were also found. Both LULC change and fire altered landscape patterns in the whole area to create a less fragmented and more contiguous landscape than in 1975. The changes induced in the whole landscape by fire, in spite of the overall low disturbance rate, were sufficient to closely determine the changes in landscape composition (LULC types) and patterns.

a b s t r a c tTorsion tests at high temperatures and high strain rates were conducted on a high nitrogen steel (HNS). Under these conditions, adiabatic heating influences its flow behavior. This work focus on a new algorithm for conducting the adiabatic heating correction of stress-strain curves. The algorithm obtains the stress-strain curves at quasi-isothermal conditions from those at adiabatic conditions. The corrections in stress obtained can be higher than 15% and increase with increasing strain rates and decreasing temperatures. On the other hand, an upper bound for the temperature rise was found using a dynamic material behavior approach. Finally, the influence of adiabatic heating correction on the Garofalo equation parameters of HNS was analyzed. High values of activation energy and stress exponent were attributed to reinforcement by dispersed particles and the high amount of alloying elements.

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A new method, Rieiro, Carsí, Ruano (RCR), for solving the Garofalo equation is developed. This method is based on an integrated algorithm that allows determination of the equation parameters for any given material and does not need initial values. The RCR method is used to analyse the Garofalo equation best fit applied to torsion data at various temperatures and strain rates from a (V–N) microalloyed steel. The predictive capability of the RCR method on experimental results is ∼6% in stress and the magnitude of the predicted errors is of the same order as the interpolation errors. On the other hand, the n value is slightly lower and the Q value slightly higher than those expected for a slip creep mechanism controlled by lattice diffusion. However, the obtained values agree with those found in the literature for microalloyed steels. These differences can be attributed to microstructure changes during deformation.

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