Oxidation-derived flavor compounds as quality indicators for packaged olive oil

Aroma compounds in packaged extra virgin olive oil can be present naturally or be derived through oxidative degradation under favorable conditions of temperature, light, and oxygen availability. In this study, the identity and quantity of flavor compounds were determined for extra virgin olive oil packaged in 0.5-L glass, poly(ethylene terephthalate), and poly(vinyl chloride) bottles and stored at 15,30, and 40°C under fluorescent light or in the dark for 1 yr. A set of mathematical equations concerning the rates of the most fundamental oxidation reactions in the oil was prepared and numerically solved, and the reaction constants were estimated for specific temperature values. Mainly, the presence of fluorescent light, followed by elevated temperature, stimulated oxidative alterations in the olive oil. Separated and identified flavor compounds were recorded for all the olive oil samples. Based on their abundance and evolution in the oil samples, those most clearly describing oxidation were hexanal, nonanal, (E)-2-decenal, (E)-2-heptenal, and 2-pentyl furan. These compounds could be used as markers of the oxidation process to monitor and describe the quality of packaged olive oil quantitatively.     

Integrating tracking with fine object segmentation

We present a novel method for on-line, joint object tracking and segmentation in a monocular video captured by a possibly moving camera. Our goal is to integrate tracking and fine segmentation of a single, previously unseen, potentially non-rigid object of unconstrained appearance, given its segmentation in the first frame of an image sequence as the only prior information. To this end, we tightly couple an existing kernel-based object tracking method with Random Walker-based image segmentation. Bayesian inference mediates between tracking and segmentation, enabling effective data fusion of pixel-wise spatial and color visual cues. The fine segmentation of an object at a certain frame provides tracking with reliable initialization for the next frame, closing the loop between the two building blocks of the proposed framework. The effectiveness of the proposed methodology is evaluated experimentally by comparing it to a large collection of state of the art tracking and video-based object segmentation methods on the basis of a data set consisting of several challenging image sequences for which ground truth data is available.     

Educational virtual environments: A ten-year review of empirical research (1999–2009)

This study is a ten-year critical review of empirical research on the educational applications of Virtual Reality (VR). Results show that although the majority of the 53 reviewed articles refer to science and mathematics, researchers from social sciences also seem to appreciate the educational value of VR and incorporate their learning goals in Educational Virtual Environments (EVEs). Although VR supports multisensory interaction channels, visual representations predominate. Few are the studies that incorporate intuitive interactivity, indicating a research trend in this direction. Few are the settings that use immersive EVEs reporting positive results on users’ attitudes and learning outcomes, indicating that there is a need for further research on the capabilities of such systems. Features of VR that contribute to learning such as first order experiences, natural semantics, size, transduction, reification, autonomy and presence are exploited according to the educational context and content. Presence seems to play an important role in learning and it is a subject needing further and intensive studies. Constructivism seems to be the theoretical model the majority of the EVEs are based on. The studies present real world, authentic tasks that enable context and content dependent knowledge construction. They also provide multiple representations of reality by representing the natural complexity of the world. Findings show that collaboration and social negotiation are not only limited to the participants of an EVE, but exist between participants and avatars, offering a new dimension to computer assisted learning. Little can yet be concluded regarding the retention of the knowledge acquired in EVEs. Longitudinal studies are necessary, and we believe that the main outcome of this study is the future research perspectives it brings to light.     

Low‐temperature sputtered mixtures of high‐κ and high bandgap dielectrics for GIZO TFTs

Abstract— This paper discusses the properties of sputtered multicomponent amorphous dielectrics based on mixtures of high‐κ and high‐bandgap materials and their integration in oxide TFTs, with processing temperatures not exceeding 150°C. Even if Ta²O⁵ films are already amorphous, multicomponent materials such as Ta²O⁵—SiO² and Ta²O⁵—Al²O³ allow an increase in the bandgap and the smoothness of the films, reducing their leakage current and improving (in the case of Ta²O⁵—SiO²) the dielectric/semiconductor interface properties when these dielectrics are integrated in TFTs. For HfO²‐ based dielectrics, the advantages of multicomponent materials are even clearer: while HfO² films present a polycrystalline structure and a rough surface, HfO²—SiO² films exhibit an amorphous structure and a very smooth surface. The integration of the multicomponent dielectrics in GIZO TFTs allows remarkable performance, comparable with that of GIZO TFTs using SiO² deposited at 400°C by PECVD. For instance, with Ta²O⁵—SiO² as the dielectric layer, field‐effect mobility of 35 cm²/(V‐sec), close to 0 V turn‐on voltage, an on/off ratio higher than 10⁶, a subthreshold slope of 0.24 V/dec, and a small/recoverable threshold voltage shifts under constant current (I^D= 10 μA) stress during 24 hours are achieved. Initial results with multilayers of SiO²/HfO²—SiO²/SiO² are also shown, allowing a lower leakage current with lower thickness and excellent device performance.     

CRAFTING THE MIND OF PROSOCS AGENTS

PROSOCS agents are software agents that are built according to the KGP model of agency. KGP is used as a model for the mind of the agent, so that the agent can act autonomously using a collection of logic theories, providing the mind's reasoning functionalities. The behavior of the agent is controlled by a cycle theory that specifies the agent's preferred patterns of operation. The implementation of the mind's generic functionality in PROSOCS is worked out in such a way so it can be instantiated by the platform for different agents across applications. In this context, the development of a concrete example illustrates how an agent developer might program the generic functionality of the mind for a simple application.     

Stability and Constitutive Modelling in Multiphase TRIP Steels

Multiphase TRIP steels are a relatively new class of steels exhibiting excellent combinations of strength and cold formability, a fact that renders them particularly attractive for automotive applications. The present work reports models regarding the prediction of the stability of retained austenite, the optimisation of the heat‐treatment stages necessary for austenite stabilization in the microstructure, as well as the mechanical behaviour of these steels under deformation. Austenite stability against mechanically‐induced transformation to martensite depends on chemical composition, austenite particle size, strength of the matrix and stress state. The stability of retained austenite is characterized by the M^σ_S temperature, which can be expressed as a function of the aforementioned parameters by an appropriate model presented in this work. Besides stability, the mechanical behaviour of TRIP steels also depends on the amount of retained austenite present in the microstructure. This amount is determined by the combinations of temperature and temporal duration of the heat‐treatment stages undergone by the steel. Maximum amounts of retained austenite require optimisation of the heat‐treatment conditions. A physical model is presented in this work, which is based on the interactions between bainite and austenite during the heat‐treatment of multiphase TRIP steels, and which allows for the selection of treatment conditions leading to the maximization of retained austenite in the final microstructure. Finally, a constitutive micromechanical model is presented, which describes the mechanical behaviour of multiphase TRIP steels under deformation, taking into account the different plastic behaviour of the individual phases, as well as the evolution of the microstructure itself during plastic deformation. This constitutive micromechanical model is subsequently used for the calculation of forming limit diagrams (FLD) for these complex steels, an issue of great practical importance for the optimisation of stretch‐forming and deep‐drawing operations.     

Fiber Reinforced Polymer Composite–Wood Pile Interface Characterization by Push-Out Tests

Structural restoration of spliced or damaged wood piles with fiber reinforced polymer (FRP) composite shells requires that shear forces be transferred between the wood core and the encasing composite shells. When a repaired wood pile is loaded, shear stresses develop between the wood pile and the FRP composite shell through the grouting material. Alternatively, shear force transfer can be developed through mechanical connectors. The objective of this study was to characterize the interfaces in wood piles repaired with FRP composite shells and grout materials. Two interfaces were studied: wood pile/grout material and a grout material/innermost FRP composite shell. A set of design parameters that control the response of both interfaces was identified: (1) extent of reduction of cross section of wood pile due to deterioration (necking); (2) type of grout material (cement-based or polyurethane); (3) use of mechanical connectors; and (4) addition of frictional coating on the innermost shell. Push-out tests by compression loading were performed to characterize the interfaces and discriminate the effect of the design parameters. The outcome of the push-out tests was evaluation of the shear stress and force versus slip response and characterization of the failure mechanism. A set of repair systems that represent different combinations of the design parameters was fabricated and the interfaces evaluated. It was found that the combination of cement-based grout and polymer concrete overlay on the innermost shell provided the most efficient shear force-slip response. A simplified piecewise linear model of shear stress versus slip at the wood/grout and grout/FRP composite interfaces with and without mechanical connectors is proposed to synthesize the experimental response.     

Targeting and synthesis of single-impurity total water systems using coordinated transhipment models

Clean Technologies and Environmental Policy - Reuse, regeneration and recycle are common practices for attaining maximum savings in industrial water networks. Additional benefits are generated when...     

Concurrent Delay Testing in Totally Self-Checking Systems

Prompt detection of even small delay faults, sometimes before causing critical paths to fail, gains importance since stricter test quality requirements for high performance and high density VLSI circuits have to be satisfied in critical applications. This can be achieved by using concurrent delay testing.In this paper a novel idea for concurrent detection of two-rail path delay faults is introduced. It is shown that TSC two-rail code error indicators that monitor pairs of paths with similar propagation delays can be used for concurrent delay testing. Our technique is applied to TSC two-rail code checkers as well as to duplication systems which are the most widely used TSC systems. The design of TSC two-rail code checkers and TSC duplication systems with respect to two-rail path delay faults is achieved for first time in the open literature.     

Autoregressive energy-efficient context forwarding in wireless sensor networks for pervasive healthcare systems

Driven by technological advances in low-power network systems and medical sensors, we have witnessed during the recent years the adoption of wireless sensor networks (WSNs) in electronic healthcare. Improving the quality of electronic healthcare and the prospects of ‘ageing in place’ through WSNs requires solving difficult problems in scale, energy management, and data acquisition. Medical and pervasive healthcare application (or mobile healthcare application) based on WSNs is influenced by many factors such as transmission errors and power consumption. We propose a multivariate context forwarding model that achieves energy-efficient WSN operation. A node adopts multivariate autoregression for forecasting contextual information (bio-signals or vital parameters) and locally decides whether context retransmission is required or not. This scheme is applied in patient telemonitoring systems where accurate yet energy-aware transmission of bio-signals to a remote control unit is crucial. Simulation results are reported indicating the capability of the proposed model in minimizing energy consumption in WSNs having as application domain the electronic healthcare systems.