1,502 research outputs found

    When Europe encounters urban governance: Policy Types, Actor Games and Mechanisms of cites Europeanization

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    This paper examines European Union (EU) causal mechanisms and policy instruments affecting the urban domain throughout the lenses of the Europeanization approach. Instead of looking at EU instruments that are formally/legally consecrated to cities, we use theoretical public policy analysis to explore the arenas and the causal mechanisms that structure the encounters between the EU and urban systems of governance. Policy instruments are related to policy arenas and in turn to different mechanisms of transmission thus originating a typology of European Policy Modes. The paper focuses on four different EU instruments in the in the macro-area of sustainable development and proposes potential game-theoretical models for each of them. In the conclusions we highlight the differences between this approach and the traditional analysis of EU urban policy, and suggest avenues for future empirical research based on typologies of policy instruments and modes of Europeanization

    Analysis of building vulnerability and firebrand exposure to mitigate wildfire damage

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    Wildfire intensity and resulting damage to communities and infrastructure is increasing worldwide; this thesis investigates the vulnerability of wildland-urban interface (WUI) buildings to wildfires, focusing on firebrand exposure. The research objective is to improve understanding of wildfire damage mechanisms to aid effective risk reduction practices. A comprehensive literature review establishes the need for quantitative building vulnerability assessments and advanced understanding of firebrand deposition and accumulation around solid obstacles. To address these needs, a statistical analysis on two large wildfire damage databases from Portugal and California is conducted to investigate the relationship between building design and damage extent. The results contribute to the development of a preliminary building resistance index (WRI) to assess building vulnerability to wildfire damage. The thesis progresses to characterise the feasibility of using the Fire Dynamics Simulator (FDS) to simulate firebrand creep movement and accumulation around solid obstacles. A sensitivity analysis quantifies the impact of input parameters on final particle position, revealing a relationship between sensitivity and the Tachikawa number, which describes the aerodynamic properties of simulated particles. A comparison between two FDS Lagrangian Particle model modalities assesses their efficacy in simulating firebrand accumulation based on previously published experimental results. The analysis explain the connection between particulate transport physical mechanisms and the effective operational FDS use for simulating wildfire firebrand exposure. FDS simulations are subsequently conducted to identify regions of firebrand contact exposure, connected to firebrand ignition hazard, around three different obstacles mimicking common building components. Results characterize the combined influence of wind speed and obstacle geometry on firebrand contact exposure. Finally, the applicability of established sand protection measures to protect infrastructure from firebrands is explored by reviewing literature and conducting exploratory FDS simulations. The effectiveness of a trench protection measure to inhibit firebrand accumulation on an infrastructure component is investigated, indicating its potential when combined with contextual information on infrastructure design and ambient conditions.Open Acces

    AUC-based gradient boosting for imbalanced classification

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    Cure monitoring of CFRP composites by dynamic mechanical analyser

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    The cure characteristics of carbon/MTM44-1 epoxy composite prepreg and neat MTM44-1 epoxy resin are monitored using a dynamic mechanical analyser (DMA). This study also assesses whether the simple containment device recommended by the DMA manufacturer for powder and gel is suitable for prepregs. The device is a disposable 0.1-mm thick stainless steel pocket. The cure behaviour of the packaged materials is compared with that of the unpackaged prepreg. All the samples are cured following the manufacturer's 180°C-isothermal schedule with heating rates of 2 °C/min and 5 °C/min. The tests highlight that: (i) the cure of composite prepregs and resin can be monitored using a DMA; (ii) the stainless steel pocket does not influence the cure of the prepreg and resin; and (iii) the softening and melting of the uncured resin, the resin low viscosity state and the subsequent gelation-vitrification-solidification of the resin are detected with this method

    Neural Mechanisms of the Reward System and the Cognitive Control System in Internet Addicts

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    As a behavioral addiction, Internet addiction has become a global problem that seriously affects people’s mental health. According to the neurobiological model of brain development, revealing the neural mechanisms of reward and the cognitive control system of Internet addicts is the key to solving internet addiction. The key to the problem of addiction is also a major issue in psychological research. Behavioral research has explored the characteristics of high reward seeking and low cognitive control in Internet addiction; research on neural mechanisms has revealed that the deficits in reward and cognitive control systems are the root of this behavior. Comparative studies with drug addiction have found that Internet addiction has a unique reward mechanism. These studies have deepened the understanding of the psychological and neural mechanisms of Internet addiction, but there are still differences in the screening and inclusion criteria for Internet addiction. There are some problems that need to be solved urgently, such as science, general classification, lack of causal research, controversial intervention and treatment effects, and loopholes in research paradigms

    Nitrated cross-linked b-cyclodextrin binders exhibiting low glass transition tempratures

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    Polymeric binders such as β‐cyclodextrins (βCDs) are used to bind with other constituents of energetic formulations and to prevent accidental ignition. One of the advantages of βCDs is the ability to tune their properties by chemical modification. Here, we synthesised nitrated cross‐linked βCDs (βNCXCDs) to produce new binders for energetic formulations. The cross‐linking of βCD with non‐toxic triethylene glycol diglycidyl ether (TEGDGE, X=T) and poly(ethylene glycol) diglycidyl ethers (PEGDGE, X=P) yielded soft, water soluble oligomeric compounds (βCXCDs) which can improve the processability of energetic formulations and contribute to their desensitisation. When the PEGDGE cross‐linker was used, lower glass transition temperatures were achieved, which extended the operative range of the βCPCD binder to −20 °C. The analogous nitrated systems (βNCXCDs) were therefore synthesised using a 1 : 1 (v/v) ratio of 98 % sulfuric acid/100 % nitric acid or 100 % fuming nitric acid, increasing their solubility in acetone and tetrahydrofuran. The nitrated derivatives were characterised by decomposition temperatures (200 °C) and energies (up to 1750 J g−1) comparable to nitrocellulose. Moreover, the glass transition of the inert βCXCDs at low temperatures (<0 °C) was conserved in the corresponding nitrated βNCXCDs, ensuring the desensitisation of energetic compositions even at low temperatures. This is the first time that nitrated derivatives of βCD with glass transition temperatures below 0 °C have been reported, suggesting such derivatives could make suitable replacements for nitrocellulose and other binders in energetic formulations

    A novel strategy for fabrication, activation and cleaning of fully 3D printed flexible planar electrochemical platforms

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    In recent years, 3D printing of carbon-based conductive filaments has received growing attention for assembling electrodes to be used in a wide variety of electroanalytical devices and applications. Despite the large amount of work present in literature concerning the development of three-dimensional (3D) conductive structures, its potential as dry deposition method for assembling two-dimensional (2D) electrodes to be used in planar configuration is still largely unexplored. In fact, the possibility to rapidly change the geometry of the electrochemical circuits, associated with the reduction of waste and the absence of solvents, which are instead important components of ink and paste formulations, makes this strategy a valid green and efficient alternative to other deposition approaches such as screen-printing technology. We report here a rapid and solvent-free method for assembling fully 3D printed flexible planar electroanalytical platforms (3DEPs) to be used with microliters of liquid. At the same time, a novel protocol for the surface pre-treatment of 3D printed electrodes based on ultrasonication in aqueous NaOH solution followed by electrochemical activation using the same medium, is presented. In addition, the same procedure has proved to be efficient for cleaning the electrode surface after electrochemical passivation, thus confirming the validity of both time-efficient and environmentally-friendly assembling and activation/cleaning procedures developed which allow efficient and reusable electrodes to be produced. Finally, 3DEPs were tested by a proof-of-concept quantification of a commonly used food dye (Brilliant Blue, E-133) in commercial solutions used for homemade food coloring

    Fast Power and Channel Adaptation for Mobile Users in OFDMA Multi-Cell Scenarios

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    Methods for interference mitigation and adaptive multi-user resource allocation are among the most promising technological breakthroughs that should improve capacity of the last generation broadband wireless systems. In multi-cell scenarios characterized by radio technologies based on OFDMA (Orthogonal Frequency Division Multiple Access), co-channel interference is the performance limiting factor and techniques that reduce the transmission power act indirectly on the co-channel interference levels. In this paper we investigate multi-cell systems in which power and channel adaptation act as a positive factor on the interference reduction. We are interested particularly in the role of the closed loop power control and of simple techniques for fast channel assignment in multi-cell scenario with low reuse factors (possibly close to 1). It is found that, in multi-cell scenarios, spectral efficiency and possibly coverage can be improved by algorithms that are simple and fast enough to be exploited for mobile users

    Thermomechanical characterisation of cross-linked β-cyclodextrin polyether binders

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    Cyclodextrins are promising building blocks for the synthesis of industrial binders. A new binder was prepared by cross-linking β-cyclodextrin with variable amounts of polyethylene glycol diglycidyl ether (40–60% w/w) to produce a soft polyether network that was soluble in water and alcohol, and the thermomechanical properties of the binder were determined. Increasing the amount of cross-linker reduced the glass transition temperature of the binder, as determined by differential scanning calorimetry and dynamic mechanical analysis. Cooling experiments revealed sudden stress relief below the glass transition temperature, reflecting the de-bonding of the polymer from the metallic supports. This was prevented by contact with polytetrafluoroethylene tape. Optical microscopy confirmed the stress relief in the form of cracking, and revealed self-healing by reptation, promoted by a higher cross-linker content and temperature. The information gained on the influence of the support medium on the thermomechanical properties of the cross-linked β-cyclodextrins can be used by industry for optimising manufacture and storage methods for new binders

    A portable electrochemiluminescence aptasensor for β-lactoglobulin detection

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    Cow’s milk allergy is one of the most common food allergies in children with a prevalence of around 2.5%. Milk contains several allergens; the main ones are caseins and β-lactoglobulin (β-LG). At regulatory level, β-LG is not explicitly named, but milk is included in the list of substances or products causing allergies or intolerances. Hence, the presence of β-LG can be a useful marker for determining the presence of milk in food. In this work, we present an aptasensor based on electrochemiluminescence (ECL) for the quantification of β-LG in real food matrices displaying integrated advantages consisting of high specificity, good sensitivity, portability, and cost effectiveness. The performance and applicability of this sensor were tested by analyzing a sample of skimmed milk and an oat-based drink proposed as a vegetable substitute for milk of animal origin. We obtained a linear correlation between the intensity of the signal and the concentration of β-LG standard solutions (y = x * 0.00653 + 1.038, R2 = 0.99). The limit of detection (LOD) and the limit of quantification (LOQ) were found to be 1.36 and 4.55 μg L−1, respectively. Graphical abstract: [Figure not available: see fulltext.
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