A methodology for evaluating environmental impacts of railway freight transportation policies

Railway freight transportation presents a degree of complexity which frequently makes impossible to model it with sufficient precision. Currently, energetic and environmental impacts of freight transportation are usually modelled following average data, which do not reflect the characteristics of specific lines. These models allow qualitative approximations which may be used as criteria for designing high-level transportation policies: road–train modal shift, regional energetic planning or environmental policies.     

Effect of sea water on biochemical properties of fruit of tomato (Lycopersicon esculentum Mill.) genotypes differing for ethylene production

BACKGROUND: Three near‐isogenic lines of cv. Gimar differing in ethylene production were used to evaluate the influence of salinity on fruit quality. Plants were grown in rockwool culture and were irrigated with nutrient solution with electrical conductivities (ECs) of 3 and 8 mS cm^?1, which corresponded to 0 and 10% of sea water. For fruits picked at ‘red‐turning’ and ‘red‐ripe’ stages physico‐chemical parameters, ethylene, ascorbate and organic acid content, and cell reductive power were analysed. RESULTS: The same response was observed in all genotypes: the higher salinity growth solution increased dry matter content, total soluble solids (TSS) and titratable acidity but reduced crop yield. Ascorbic acid and also organic acid contents showed a greater accumulation with ripening in the mutant genotypes: this might be due to a slowing of ripening. Our data confirm the lack of any relationship between the larger accumulation of TSS and ethylene production in the fruits of salt‐treated plants. CONCLUSION: These findings suggest that although salinity (10% sea water) reduces fruit yield, it does not have a negative effect on quality. So, it seems possible that controlled use of diluted sea water, combined with suitable tomato genotypes might represent a valid alternative to fresh irrigation water. Copyright © 2007 Society of Chemical Industry     

Atomistic fracture: QFM vs. MD

In this work we discuss the paradigmatic case of brittle fracture in defective elastic-plastic cubic silicon carbide, by a combination of Quantized Fracture Mechanics and Molecular Dynamics atomistic simulations. Different defect sizes and shapes, or crack-inclusion interactions are considered. Our results show that Quantized Fracture Mechanics is able to effectively incorporate the main lattice-related features, while Molecular Dynamics atomistic simulations do provide the most basic level of understanding of mechanical behaviour of brittle materials.     

Effects of chestnut tannins on carcass characteristics, meat quality, lipid oxidation and fatty acid composition of rabbits

Seventy two male Bianca Italiana rabbits were used to study the effects of the inclusion (0%, 0.5%, and 1.0%) of a natural extract of chestnut wood (Silvafeed ENC) in the diet on productive traits, carcass characteristics, meat quality, lipid oxidation and fatty acid composition of rabbit meat. Results showed ENC had no significant effect on live weight, productive traits, hot carcass weight, dressing percentage, skin weight, pH, cooking losses, shear force and colour. The iron content was higher in Longissimus thoracis et lumborum (LTL) muscle of rabbit fed the ENC 1.0% diet than the control group. TBARS average values in the group ENC 0.5% were significantly lower (P < 0.05) than in the control and ENC 1.0% groups. Myristic acid (C14:0; P < 0.01), palmitoleic acid (C16:1 cis-9; P < 0.05) and pentadecanoic acid (C15:0; P < 0.01) contents were lower in LTL muscle of rabbits fed the ENC 1.0% diet, whereas the palmitic acid (C16:0) content was higher (P < 0.05) in the rabbits of this group. Moreover, the rabbits fed with the ENC 0.5% diet had lower (P < 0.01) levels of trans-vaccenic acid (C18:1 trans-11) compared to rabbits fed with the control diet. No significant differences were observed in saturated (SFA), monounsaturated (MUFA), polyunsaturated (PUFA) fatty acids, as well as in PUFA/SFA and n − 6/n − 3 ratios among the groups.     

Physiological basis of sensitivity to enzymatic browning in ‘lettuce’, ‘escarole’ and ‘rocket salad’ when stored as fresh-cut products

In fresh-cut leafy vegetables, the operation of cutting may stimulate enzymatic browning, with important commercial consequences. In this work, a number of physiological and biochemical parameters, including the activities of key enzymes involved in the metabolism of phenols (such as PAL, PPO, and PODs) and ascorbic acid (ASA), were measured in three species: lettuce (Lactuca sativa var. capitata L.), escarole (Cichorium indivia var. latifolium) and rocket salad (Eruca sativa), upon cold storage as fresh cuts. The first two species are quite sensitive to leaf browning, which does not affect rocket salad.     

Luminescence of heat-treated silicon-based polymers: promising materials for LED applications

A new strategy to obtain transparent, thermally stable, and formable photoluminescent materials for LED applications is presented. Starting from commercially available silicon-based polymers, luminescence properties are developed by means of simple heat treatment. Solid polymethylsilsesquioxane MK (Wacker-Besil^®PMS MK) and liquid poly(ureamethylvinyl)silazane Ceraset (Kion Ceraset^® PUVMS) were thermally treated between 200 and 700 °C for 2 h under Ar atmosphere. Photoluminescence properties were observed in all the samples. The structural rearrangements during thermal annealing were effective in order to red-shift the emission spectra of the untreated polymers to the visible range. The formation of dangling bonds and carbon sp², associated with the annealing procedure and confirmed by means of Electron Paramagnetic Resonance (EPR) spectroscopy and solid state Magic Angle Spinning NMR (MAS-NMR) contribute to the red-shift of the photoluminescence emissions of the polymers. After heat treatment at low temperatures (200, 300, and 400 °C), both the polymers show fluorescence in the UV range. While the polysiloxane reveals white luminescence after annealing at 500 and 600 °C, the polysilazane heat-treated at 500 °C exhibits emission in the blue-green range and is transparent. At higher temperatures the presence of free carbon counteracts the luminescence properties.     

Real-time interaction of virtual and physical objects in mixed reality applications

We present a real-time method for computing the mechanical interaction between real and virtual objects in an augmented reality environment. Using model order reduction methods we are able to estimate the physical behavior of deformable objects in real time, with the precision of a high-fidelity solver but working at the speed of a video sequence. We merge tools of machine learning, computer vision, and computer graphics in a single application to describe the behavior of deformable virtual objects allowing the user to interact with them in a natural way. Three examples are provided to test the performance of the method.     

A generalized reduced fluid dynamic model for flow fields and electrodes in redox flow batteries

High-dimensional models typically require a large computational overhead for multiphysics applications, which hamper their use for broad-sweeping domain interrogation. Herein, we develop a modeling framework to capture the through-plane fluid dynamic response of electrodes and flow fields in a redox flow cell, generating a computationally inexpensive two-dimensional (2D) model. We leverage a depth-averaging approach that also accounts for variations in out-of-plane fluid motion and departures from Darcy's law that arise from averaging across three-dimensions (3D). Our resulting depth-averaged 2D model successfully predicts the fluid dynamic response of arbitrary in-plane flow field geometries, with discrepancies of <5% for both maximum velocity and pressure drop. This corresponds to reduced computational expense, as compared to 3D representations (<1% of duration and 10% of RAM usage), providing a platform to screen and optimize a diverse set of cell geometries.     

Controlling Electrochemically Induced Volume Changes in Conjugated Polymers by Chemical Design: from Theory to Devices

Electrochemically induced volume changes in organic mixed ionic-electronic conductors (OMIECs) are particularly important for their use in dynamic microfiltration systems, biomedical machinery, and electronic devices. Although significant advances have been made to maximize the dimensional changes that can be accomplished by OMIECs, there is currently limited understanding of how changes in their molecular structures impact their underpinning fundamental processes and their performance in electronic devices. Herein, a series of ethylene glycol functionalized conjugated polymers is synthesized, and their electromechanical properties are evaluated through a combined approach of experimental measurements and molecular dynamics simulations. As demonstrated, alterations in the molecular structure of OMIECs impact numerous processes occurring during their electrochemical swelling, with sidechain length shortening decreasing the number of incorporated water molecules, reducing the generated void volumes and promoting the OMIECs to undergo different phase transitions. Ultimately, the impact of these combined molecular processes is assessed in organic electrochemical transistors, revealing that careful balancing of these phenomena is required to maximize device performance.