Applying SRTM digital elevation model to unravel Quaternary drainage in forested areas of Northeastern Amazonia

There has been an increasing number of articles stressing the advantage of applying remote sensing products of synthetic aperture radar (SAR) and interferometric synthetic aperture radar (InSAR) for rapidly enhancing the volume of geological data in Amazonian areas, where forest cover is dense and high, clouds are abundant and accessibility is limited. The majority of these studies has emphasized geomorphology as a tool for both discussing tectonic reactivations during the Cenozoic and reconstructing Quaternary paleolandscapes. This work applies Digital Elevation Model (DEM) derived from the Shuttle Radar Topography Mission (SRTM) for delineating past morphological features under dense rainforest in an Amazonian lowland area. Previous use of this tool in southwestern Marajó Island (northern Brazil) helped to delineate, with exceptional precision, a paleochannel network hidden under the rainforest, which would be barely detected with other available remote sensing products. Fieldwork revealed that these paleochannels are related to palimpsest drainage systems developed mostly during the last 40,000 ¹⁴C yr B.P. Measured altitudes acquired during topographic surveys attested that paleochannel areas are slightly higher than adjacent floodplains. This fact determined the successful application of SRTM–DEM for mapping paleochannels in Marajó Island. Integration of SRTM data with sedimentological information collected during fieldwork suggests paleoflows derived from continental areas located to south of the study area. This paleodrainage was active when the island was still connected to mainland. With island detachment due to reactivation of tectonic faults, the channels became abandoned and were progressively forested. The results obtained in the present study indicate that SRTM–DEM has high potential for unraveling similar morphological features from many other Amazonian areas with low topography and a dense forest cover.     

On the expressiveness and decidability of higher-order process calculi

In higher-order process calculi, the values exchanged in communications may contain processes. A core calculus of higher-order concurrency is studied; it has only the operators necessary to express higher-order communications: input prefix, process output, and parallel composition. By exhibiting a deterministic encoding of Minsky machines, the calculus is shown to be Turing complete. Therefore its termination problem is undecidable. Strong bisimilarity, however, is shown to be decidable. Furthermore, the main forms of strong bisimilarity for higher-order processes (higher-order bisimilarity, context bisimilarity, normal bisimilarity, barbed congruence) coincide. They also coincide with their asynchronous versions. A sound and complete axiomatization of bisimilarity is given. Finally, bisimilarity is shown to become undecidable if at least four static (i.e., top-level) restrictions are added to the calculus.     

Determination of critical storage conditions of coffee oil microcapsules by coupling water sorption isotherms and glass transition temperature

Coffee oil microcapsules were produced by spray‐drying using as encapsulating agents gum Arabic, whey protein isolate (WPI) and mixtures of maltodextrin (MD) and WPI, at three different proportions (3:1, 1:1 and 1:3). Sorption isotherms were determined by the gravimetric method, and the glass transition temperature (T_g) was measured by differential scanning calorimetry. Microcapsules produced with gum Arabic showed the highest water adsorption and underwent a stronger water plasticising effect. At the highest water activity (0.843), this sample had a T_g value of ?18.3 °C, while those produced with WPI at higher proportions showed values around 25 and 30 °C. The good fit of experimental data by Guggenheim‐Anderson‐de Boer and Gordon–Taylor models allowed the determination of the critical storage conditions, at which powders are not susceptible to deteriorative physical changes. The samples produced with 1:1 and 1:3 of MD/WPI were the most stable ones, showing critical water activity values of 0.890 and 0.938, respectively.     

Mango (Mangifera indica L.) leaf extracts as ingredient for the formulation of functional beverages with biological activity

The biological activity of mango leaf extracts from different mango varieties was evaluated in terms of total phenolic content, flavonoids, antioxidant activity and inhibition of α-amylase and α-glucosidase enzymes. Leaf extract-based beverages were formulated and evaluated for some physicochemical, microbiological and sensory properties. Results indicated that the extract from 'Tommy Atkins' mango leaves had the highest total phenols content (137.08 mg of GAE g⁻¹) and antioxidant activity (DDPH = 38.26 mg TEAC 100 g⁻¹; ABTS = 59.13 mg TEAC 100 g⁻¹). The beverage formulated with 20% leaf extract presented the highest percentage of antioxidant activity (38.63%) and inhibition of enzymes α-amylase (41.9%) and α-glucosidase (37.53%). All beverages presented a yellow hue and consumers rated it with a degree of liking between 4.8 and 7.3 according to a hedonic scale. Results showed that the biological properties of beverages could be an alternative for the control of free radicals and glucose levels.     

Natural Ageing of Automotive Polymer Components: Characterisation of New and Used Poly(propylene) based Car Bumpers

The chemical and morphological structure of new and post‐consumer ten years old poly(propylene) based car bumpers has been investigated and their mechanical properties have been correlated to the chemical and physical degradation of the material. Poly(propylene) matrix and a rubbery ethylene‐propylene phase were the constituents of the bumpers. A strong impairment of the mechanical properties has been found in old samples which showed also a distinctive phase separation. The modification of the chemical structure was much less evident: oxidation on the exposed surface involving the poly(propylene) phase has been highlighted in old bumpers, and possible crosslinking. These relatively small changes, however, are responsible for the pronounced physical ageing. A tentative explanation is a poor interfacial adhesion of rubber particles from which the crazes can propagate further to form cracks.     

Numerical solution of free boundary problems in seepage flow with capillary fringe

A free boundary problem related to the stationary flow in a porous medium in which the capillary fringe is taken account of is analyzed and solved numerically.In particular two different numerical methods are applied. With the first method by means of a suitable transformation the solution of the problem is equivalent to the search for the minimum of a quadratic functional on a fixed domain.The second method applies a classical idea and determines the free boundary by means of successive approximations. The results of the two methods are compared with each other and with those obtained by means of an analogous model and found to be in good agreement.The first method, which is a new one, is better justified on a theoretical level and moreover is more convenient with regard to the programming effort and the execution time needed to carry it out on a computer.     

Near Real-Time Optimization of Multi-Reservoir during Flood Season in the Fengman Basin of China

This study aims to develop a multi-objective optimization model in a multi-reservoir system during flood season using Numerical Weather Predictions (NWPs) outputs (short forecast). The optimization model was coupled with the Water and Energy Budget-based Distributed Hydrological Model that was used to forecast the reservoir inflows. The model was forced by 8-day lead time global deterministic NWPs by Japan Meteorological Agency. The reservoir objective function was established by considering the reservoir and upstream safety, downstream safety and future water use. The model was applied to the Baishan-Fengman multi-reservoir system of Northeast China. The results have demonstrated the model with high efficiency in optimizing reservoir objectives for all of the reservoirs. The sensitivity of the system to lead time and decision time were investigated. With the decreasing of lead time, the dam release peaks decrease and the end water levels increase. This is mainly due to the fact that the model with longer lead time needs to keep storage capacity for detected floods during long lead time period. The variation amplitude of dam releases and water levels decrease with the increasing of decision time due to the smoothing of floods and dam releases during long decision period. The model is easy to operate and is able to be coupled with other hydrological models or earth system models.