Model comprehension for security risk assessment: an empirical comparison of tabular vs. graphical representations

Tabular and graphical representations are used to communicate security risk assessments for IT systems. However, there is no consensus on which type of representation better supports the comprehension of risks (such as the relationships between threats, vulnerabilities and security controls). Cognitive fit theory predicts that spatial relationships should be better captured by graphs. In this paper we report the results of two studies performed in two countries with 69 and 83 participants respectively, in which we assessed the effectiveness of tabular and graphical representations with respect to extraction correct information about security risks. The experimental results show that tabular risk models are more effective than the graphical ones with respect to simple comprehension tasks and in some cases are more effective for complex comprehension tasks. We explain our findings by proposing a simple extension of Vessey’s cognitive fit theory as some linear spatial relationships could be also captured by tabular models.     

A hierarchical hybrid neural model with time integrators in long-term load forecasting

A novel hierarchical hybrid neural model to the problem of long-term load forecasting is proposed in this paper. The neural model is made up of two self-organizing map nets—one on top of the other—and a single-layer perceptron. It has application into domains which require time series analysis. The model is compared to a mutilated architecture of it, and to a multilayer perceptron. The hierarchical, the mutilated, and the multilayer perceptron models are trained and assessed on load data extracted from a North-American electric utility. They are required to predict either once every week or once every month the electric peak-load during the next two years. The results from the experiments show that the performance of HHNM on long-term load forecasts is better than that of the mutilated model, and much better than that of the MLP model.     

Physics students’ performance using computational modelling activities to improve kinematics graphs interpretation

The purpose of this study was to investigate undergraduate students’ performance while exposed to complementary computational modelling activities to improve physics learning, using the softwares Modellus. Interpretation of kinematics graphs was the physics topic chosen for investigation. The theoretical framework adopted was based on Halloun’s schematic modelling approach and on Ausubel’s meaningful learning theory. The results of this work show that there was a statistically significant improvement in the experimental group students’ performance when compared to the control group, submitted just to a conventional teaching method. Students’ perception with respect to the concepts and mathematical relations, as well as the motivation to learn, originated by the activities, have played a fundamental role in these findings.     

Advanced Collagen‐Based Biomaterials for Regenerative Biomedicine

In recent decades, collagen is one of the most versatile biomaterials used in biomedical applications, mostly due to its biomimetic and structural composition in the extracellular matrix (ECM). Several attempts are proposed for designing innovative collagen‐based biomaterials and applying them in tissue regeneration. The regeneration of different tissues is prompted by different types and diverse physical forms of collagen‐based biomaterials prepared by various methods. Based on such concepts, the source, structure, and classification of collagen are briefly introduced in this review. Here, the commonly used physical forms and modification methods of collagen‐based biomaterials are reviewed, including hydrogels, scaffolds, and microspheres, followed by their applications in the regeneration of tissues and organs. Important proof‐of‐concept examples are described to demonstrate the outcomes on material characteristics, cellular reactions, and tissue regeneration. A concise assessment of the limitations that still exist and the developing trends in the future of collagen‐based biomaterials are put forward.     

Inhibition of Yersinia enterocolitica by Lactobacillus sake strains of meat origin

The growth of Yersinia enterocolitica at 4, 8, 15 and 24°C, in mixed cultures with Lactobacillus sake strains previously isolated from Spanish dry fermented sausages was investigated. Growth of Y. enterocolitica was affected by L. sake strains at all temperatures studied. The inhibition was higher as the incubation temperature increased. L. sake 148, a bacteriocinogenic strain, was less inhibitory to Y. enterocolitica growth than L. sake 23, a stronger lactic acid producer strain. The low pH and the lactic acid produced by the lactobacilli seem to be major factors contributing to the inhibition of Y. enterocolitica strains.     

Fatigue properties of combined friction stir and adhesively bonded AA6082‐T6 overlap joints

Even though friction stir welding (FSW) has been shown to produce high performing butt joints, stress concentration at the weld edges in overlap FSW significantly reduces the performance of these joints. By combining FSW and adhesive bonding into a friction stir (FS) weld bonding, joint mechanical performance is greatly improved. Quasistatic and fatigue strength of the proposed FS weld‐bonding joints was assessed and benchmarked against overlap FSW and adhesive bonding. The characterization of the structural adhesive is also presented, including differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), as well as mechanical characterization with curing temperature. A small process parameter study was made to select proper FSW parameters for AA6082‐T6 overlap FSW and FS weld‐bonded joints. FS weld bonding achieved a significant increase in quasistatic and fatigue strength when compared with overlap FSW, with 79.9% of the fatigue strength of adhesive‐bonded joints at 10⁶ cycles, whereas FSW had 41.6%.     

Non‐Newtonian Thermosensitive Nanofluid Based on Carbon Dots Functionalized with Ionic Liquids

Non‐Newtonian nanofluids present outstanding features in terms of energy transfer and conductivity with high application in numerous areas. In this work, non‐Newtonian nanofluids based on carbon dots (Cdots) functionalized with ionic liquids (ILs) are developed. The nanofluids are produced using a simple, single‐step method where the raw materials for the Cdots synthesis are glucose and waste biomass (chitin from crab shells). The use of ILs as both reaction media and functionalization molecules allows for the development of a new class of nanofluids, where the ILs on the Cdots surface represent the base‐fluid. Here, the well‐known benign IL 1‐butyl‐3‐methylimidazolium chloride ([Bmim]Cl) and a novel home‐made IL (1‐tosylate‐3‐methyl‐imidazolium triflate) [Tmi][Trif] are used. The nanofluids obtained from both substrates show, apart from high conductivity and viscosity, light absorption, and good wettability, an appealing thermal sensitivity behavior. This thermal sensitivity is preserved even when applied as thin films on glass slides and can be boosted using the surface plasmon resonance effect. The results reported demonstrate that the new Cdots/IL‐based nanofluids constitute a versatile and cost‐effective route for achieving high‐performance thermosensitive non‐Newtonian sustainable nanofluids with tremendous potential for the energy coatings sector and heat transfer film systems.     

Assessing Stability and Dynamics in Flood Risk Governance

European urban agglomerations face increasing flood risks due to urbanization and the effects of climate change. These risks are addressed at European, national and regional policy levels. A diversification and alignment of Flood Risk Management Strategies (FRMSs) can make vulnerable urban agglomerations more resilient to flooding, but this may require new Flood Risk Governance Arrangements (FRGAs) or changes in existing ones. While much technical knowledge on Flood Risk Management is available, scientific insights into the actual and/or necessary FRGAs so far are rather limited and fragmented. This article addresses this knowledge gap by presenting a research approach for assessing FRGAs. This approach allows for the integration of insights from policy scientists and legal scholars into one coherent framework that can be used to identify Flood Risk Management Strategies and analyse Flood Risk Governance Arrangements. In addition, approaches for explaining and evaluating (shifts in) FRGAs are introduced. The research approach is illustrated by referring to the rise of the Dutch risk-based approach called ‘multi-layered safety’ and more specifically its application in the city of Dordrecht. The article is concluded with an overview of potential next steps, including comparative analyses of FRGAs in different regions. Insights in these FRGAS are crucial to enable the identification of action perspectives for flood risk governance for actors at the level of the EU, its member states, regional authorities, and public-private partnerships.     

Adsorption of acid orange 7 dye in aqueous solutions by spent brewery grains

Spent brewery grains (SBG), a by-product of the brewing process, were tested as an adsorbent of acid orange 7 dye (AO7), a monoazo acid dye currently used in paper and textile industries. The presence of AO7 in these effluents causes obvious environmental problems.

Kinetics studies of adsorption of AO₇ to SBG (3.75%, m/v) were carried out at 20 °C, using aqueous solutions with different AO7 concentrations (30–834 mg/L). For every situations tested, no significant variation in residual AO7 concentration in solution was detected after 1 h contact between the dye and the adsorbent. The adsorption process followed a pseudo-first order model.

The equilibrium process showed to be well described by both Freundlich and Langmuir isotherm models, at 20 and 30 °C. The maximum adsorption capacity was estimated to be 30.5 mg AO7/g SBG, at 30 °C.

Free energy of adsorption (ΔG°), enthalpy (ΔH°), and entropy (ΔS°) changes were calculated to predict the nature of adsorption. The estimated values for ΔG° were −22.78 and −24.53 kJ/mol, respectively, at 293.3 K (20 °C) and 303.3 K (30 °C), which are rather low indicating that a spontaneous process occurred. The enthalpy changes and entropy of adsorption were 28.66 and 175.36 J/mol K, respectively. The positive value for ΔH° indicates that the adsorption of AO7 dye to SBG is an endothermic process. The positive value of entropy reflects the affinity of the adsorbent for AO7 dye.

The obtained results are very promising since: (i) high levels of colour removal (>90%) were achieved with low contact times adsorbent/dye (less than 1 h contact); and (ii) the whole SBG can be successfully used as adsorbent of AO7 dye in aqueous solution without needing any previous treatments such as milling and/or sieving. Spent grains, being a cheap, and easily available material, can be an alternative for more costly adsorbents used for dye removal in wastewater treatment processes.