The transition between the cubic and tetragonal phase in SrTiO 3 shows an excess specific heat of 0.0035 J g −1 K −1 . Comparison between the temperature evolution of the excess entropy S = (C/T ) dT and the structural order parameter Q shows S ∝ Q 2 within experimental errors (γ = 1.004±0.006). The apparent order parameter exponent β = 0.35±0.02 was confirmed and analysed using a Landau-type expression for the excess Gibbs free energy

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The aim of this research was to implement a methodology through the generation of a supervised classifier based on the Mahalanobis distance to characterize the grapevine canopy and assess leaf area and yield using RGB images. The method automatically processes sets of images, and calculates the areas (number of pixels) corresponding to seven different classes (Grapes, Wood, Background, and four classes of Leaf, of increasing leaf age). Each one is initialized by the user, who selects a set of representative pixels for every class in order to induce the clustering around them. The proposed methodology was evaluated with 70 grapevine (V. vinifera L. cv. Tempranillo) images, acquired in a commercial vineyard located in La Rioja (Spain), after several defoliation and de-fruiting events on 10 vines, with a conventional RGB camera and no artificial illumination. The segmentation results showed a performance of 92% for leaves and 98% for clusters, and allowed to assess the grapevine’s leaf area and yield with R2 values of 0.81 (p < 0.001) and 0.73 (p = 0.002), respectively. This methodology, which operates with a simple image acquisition setup and guarantees the right number and kind of pixel classes, has shown to be suitable and robust enough to provide valuable information for vineyard management.

by jerky propagation of phase fronts related to the appearance of avalanches. In this paper we describe a full analysis of this avalanche behavior using calorimetric heat flux measurements and acoustic emission measurements. Two different propagation modes, namely smooth front propagation and jerky avalanches, were observed in extremely slow measurements with heating and cooling rates as low as a few 10 Avalanches appear to be more common for heating rates faster than 5 10 -3 K/h whereas smooth front propagation occurs in all calorimetric measurements and (almost) exclusively for slower heating rates. Repeated cooling runs were taken after a waiting time of 1 month (and an intermediate heating run). Correlations between the avalanche sequences of the two cooling runs were found for the strongest avalanche peaks but not for the full sequence of avalanches. The memory effect is hence limited to strong avalanches.3

Feeding the growing global population requires an annual increase in food production. This requirement suggests an increase in the use of pesticides, which represents an unsustainable chemical load for the environment. To reduce pesticide input and preserve the environment while maintaining the necessary level of food production, the efficiency of relevant processes must be drastically improved. robotic systems for effective weed and pest control aimed at diminishing the use of agricultural chemical inputs, increasing crop quality and improving the health and safety of production operators. To achieve this overall objective, a fleet of heterogeneous ground and aerial robots was developed and equipped with innovative sensors, enhanced endeffectors and improved decision control algorithms to cover a large variety of agricultural situations. This article describes the scientific and technical objectives, challenges and outcomes achieved in three common crops.

Time-resolved reflectance spectroscopy can be used to assess nondestructively the bulk (rather than the superficial) optical properties of highly diffusive media. A fully automated system for time-resolved reflectance spectroscopy was used to evaluate the absorption and the transport scattering spectra of fruits in the red and the near-infrared regions. In particular, data were collected in the range 650-1000 nm from three varieties of apples and from peaches, kiwifruits, and tomatoes. The absorption spectra were usually dominated by the water peak near 970 nm, whereas chlorophyll was detected at 675 nm. For ail species the scattering decreased progressively with increasing wavelength. A best fit to water and chlorophyll absorption line shapes and to Mie theory permitted the estimation of water and chlorophyll content and the average size of scattering centers in the bulls; of intact fruits.

Fmit firmness measurement is a good way to monitor fmit softening and to predict bmising damage during harvest and postharvest handling. Ripening protocols traditionally utilize a destmctive penetrometer-type fmit firmness measure to monitor ripening. Until recently, methods of assessing fmit texture properties nondestmctively were not commercially available. The nondestmctive Sinclair iQ™ firmness tester was investigated to monitor ripening and predict bmising susceptibility in stone fmit. This work was carried out on four peach, three plum, and five nectarine cultivars over two seasons. The correlations between destmctive and nondestmctive firmness measurements were significant (p-value = 0.0001), although too low for commercial applications as they varied from ^ = 0.60-0.71 according to fmit type. Using a different approach, the relationship between destmctive and nondestmctive firmness measures was characterized in terms of segregating these fmit according to their stages of ripening. This was done by using discriminant analysis (66-90% agreement in ripeness stage classification was observed in validation tests). Discriminant analysis consistently segregated nondestmctive firmness measured fmit into commercially important classes ("ready to eat", "ready to buy", "mature and immature"). These represented key ripening stages with different bmising potentials and consumer acceptance. This work points out the importance to relate nondestmctive measurements directly to important commercial physiological stages rather than to correlate them with the current standard penetrometer valúes. Thus, destmctive and nondestmctive firmness measurements can be directly used to identify the stage of ripeness and potential susceptibility to bmising during postharvest changes. Further work is recommended to evalúate the performance of this nondestmctive sensor in segregating fmit according to their stage of ripeness under packinghouse or processing plant conditions.

The development of sensors to measure fruit internal quality variables is one of the challenges of post-harvest technology. Several variables can currently be measured, including sugar content, acid content, firmness and internal disorders. This article reviews the state of the art of non-destructive fruit firmness sensors. These include static and on-line sensors that use different technologies for determining force-deformation relationships, impact forces, the acoustic response to vibrations or impacts, and optical properties. The rebound technique and nuclear magnetic resonance is also used. Although many techniques are under development, some companies already market instruments that determine the internal quality of fruit.