Dynamical behaviour of multi-particle large-scale systems

Collective behaviours can be observed in both natural and man-made systems composed of a large number of elemental subsystems. Typically, each elemental subsystem has its own dynamics but, whenever interaction between individuals occurs, the individual behaviours tend to be relaxed, and collective behaviours emerge. In this paper, the collective behaviour of a large-scale system composed of several coupled elemental particles is analysed. The dynamics of the particles are governed by the same type of equations but having different parameter values and initial conditions. Coupling between particles is based on statistical feedback, which means that each particle is affected by the average behaviour of its neighbours. It is shown that the global system may unveil several types of collective behaviours, corresponding to partial synchronisation, characterised by the existence of several clusters of synchronised subsystems, and global synchronisation between particles, where all the elemental particles synchronise completely.

Hybrid wired/wireless PROFIBUS architectures: performance study based on simulation models

The problem of providing a hybrid wired/wireless communications for factory automation systems is still an open issue, notwithstanding the fact that already there are some solutions. This paper describes the role of simulation tools on the validation and performance analysis of two wireless extensions for the PROFIBUS protocol. In one of them, the Intermediate Systems, which connect wired and wireless network segments, operate as repeaters. In the other one the Intermediate Systems operate as bridge. We also describe how the analytical analysis proposed for these kinds of networks can be used for the setting of some network parameters and for the guaranteeing real-time behaviour of the system. Additionally, we also compare the bridge-based solution simulation results with the analytical results.

An approach for reliability-based robust design optimisation of angle-ply composites

Variations of manufacturing process parameters and environmental aspects may affect the quality and performance of composite materials, which consequently affects their structural behaviour. Reliability-based design optimisation (RBDO) and robust design optimisation (RDO) searches for safe structural systems with minimal variability of response when subjected to uncertainties in material design parameters. An approach that simultaneously considers reliability and robustness is proposed in this paper. Depending on a given reliability index imposed on composite structures, a trade-off is established between the performance targets and robustness. Robustness is expressed in terms of the coefficient of variation of the constrained structural response weighted by its nominal value. The Pareto normed front is built and the nearest point to the origin is estimated as the best solution of the bi-objective optimisation problem.

Mechanical behaviour analysis of polyester polymer mortars modified with recycled GFRP waste materials

In this study the effect of incorporation of recycled glass-fibre reinforced polymer (GFRP) waste materials, obtained by means of milling processes, on mechanical behaviour of polyester polymer mortars was assessed. For this purpose, different contents of recycled GFRP waste powder and fibres, with distinct size gradings, were incorporated into polyester based mortars as sand aggregates and filler replacements. Flexural and compressive loading capacities were evaluated and found better than unmodified polymer mortars. GFRP modified polyester based mortars also show a less brittle behaviour, with retention of some loading capacity after peak load. Obtained results highlight the high potential of recycled GFRP waste materials as efficient and sustainable reinforcement and admixture for polymer concrete and mortars composites, constituting an emergent waste management solution.

Experiments on new polymer based mortars filled with FRP waste recyclates - a quantitative analysis

Glass fibre-reinforced plastics (GFRP) have been considered inherently difficult to recycle due to both: cross-linked nature of thermoset resins, which cannot be remolded, and complex composition of the composite itself. Presently, most of the GFRP waste is landfilled leading to negative environmental impacts and supplementary added costs. With an increasing awareness of environmental matters and the subsequent desire to save resources, recycling would convert an expensive waste disposal into a profitable reusable material. In this study, efforts were made in order to recycle grinded GFRP waste, proceeding from pultrusion production scrap, into new and sustainable composite materials. For this purpose, GFRP waste recyclates, were incorporated into polyester based mortars as fine aggregate and filler replacements at different load contents and particle size distributions. Potential recycling solution was assessed by mechanical behaviour of resultant GFRP waste modified polymer mortars. Results revealed that GFRP waste filled polymer mortars present improved flexural and compressive behaviour over unmodified polyester based mortars, thus indicating the feasibility of the waste reuse in polymer mortars and concrete. © 2011, Advanced Engineering Solutions.

Wuthering heights on the screen: exploring the relations between film adaptation and subtitling

This essay aims to confront the literary text Wuthering Heights by Emily Brontë with five of its screen adaptations and Portuguese subtitles. Owing to the scope of the study, it will necessarily afford merely a bird‘s eye view of the issues and serve as a starting point for further research. Accordingly, the following questions are used as guidelines: What transformations occur in the process of adapting the original text to the screen? Do subtitles update the film dialogues to the target audience‘s cultural and linguistic context? Are subtitles influenced more by oral speech than by written literary discourse? Shouldn‘t subtitles in fact reflect the poetic function prevalent in screen adaptations of literary texts? Rather than attempt to answer these questions, we focus on the objects as phenomena. Our interdisciplinary undertaking clearly involves a semio-pragmatic stance, at this stage trying to avoid theoretical backdrops that may affect our apprehension of the objects as to their qualities, singularities, and conventional traits, based on Lucia Santaella‘s interpretation of Charles S. Peirce‘s phaneroscopy. From an empirical standpoint, we gather features and describe peculiarities, under the presumption that there are substrata in subtitling that point or should point to the literary source text, albeit through the mediation of a film script and a particular cinematic style. Therefore, we consider how the subtitling process may be influenced by the literary intertext, the idiosyncrasies of a particular film adaptation, as well as the socio-cultural context of the subtitler and target audience. First, we isolate one of the novel‘s most poignant scenes – ‗I am Heathcliff‘ – taking into account its symbolic play and significance in relation to character and plot construction. Secondly, we study American, English, French, and Mexican adaptations of the excerpt into film in terms of intersemiotic transformations. Then we analyze differences between the film dialogues and their Portuguese subtitles.

Real-Time Tariffs for Electric Vehicles in Wind Power based Power Systems

The use of Electric Vehicles (EVs) will change significantly the planning and management of power systems in a near future. This paper proposes a real-time tariff strategy for the charge process of the EVs. The main objective is to evaluate the influence of real-time tariffs in the EVs owners’ behaviour and also the impact in load diagram. The paper proposes the energy price variation according to the relation between wind generation and power consumption. The proposed strategy was tested in two different days in the Danish power system. January 31st and August 13th 2013 were selected because of the high quantities of wind generation. The main goal is to evaluate the changes in the EVs charging diagram with the energy price preventing wind curtailment.

Sherlock Holmes: from paper to the screen

Dissertação de Mestrado apresentado ao Instituto de Contabilidade e Administração do Porto para a obtenção do grau de Mestre em Tradução e Interpretação Especializadas, sob orientação da doutora Clara Sarmento Esta versão não contém as críticas e sugestões dos elementos do júri

Effects of a home-based exercise program in body composition, abdominal fat and lipid profile in patients with coronary artery disease

Introduction: Coronary artery disease and aging seems to be associated with a sedentary lifestyle, contributing to increased abdominal fat and consequently metabolic complications. The exercise can break this cycle by stimulating lipolysis and the use of fatty acids. In Europe there is still a lack of cardiac rehabilitation programmes in hospitals, therefore, this study aims to demonstrate the advantages of implementing home-based exercise programmes, as well as, their effects on cardiovascular prevention. This study analyzed the effects of a home-based exercise programme, in patients with coronary artery disease (myocardial infarction for 1 year), in body composition, abdominal fat, lipid profile. Methods: An ongoing randomized controlled trial with a sample of 20 participants were randomly allocated to intervention (n = 10) and control groups (n = 10). Intervention group performed a specific exercise programme during 8 weeks, consisting of ten home based exercises taking into account flexibility, muscle endurance and strength as well as cardiovascular endurance. Skinfolds thickness were measure to calculate the percentage of total fat: Skinfolds used were suprailiac, abdominal horizontal and vertical. Body mass index calculation and blood tests for lipidic profile were performed. Results: After eight weeks the intervention group decreased significantly the percentage of total fat (p < 0.05), the suprailiac skinfold (p < 0.05), the abdominal horizontal and vertical skinfold (p < 0.05) when compared with control group. In the intervention group it was observed after 8 weeks a significant decrease in body mass index, LDL-cholesterol and triglycerides. Conclusions: Home-based exercise programme influenced body composition, abdominal fat and lipid profile. These results highlight the importance of implementing home based exercises that are easy and cheap to implement in cardiac patients, in order to promote health and reduce cardiovascular risk factors.

Electrospun Polyaniline-Reduced Graphene Oxide Composite Nanofibers Based High Sensitive Ammonia Gas Sensor

Ammonia is an important gas in many power plants and industrial processes so its detection is of extreme importance in environmental monitoring and process control due to its high toxicity. Ammonia’s threshold limit is 25 ppm and the exposure time limit is 8 h, however exposure to 35 ppm is only secure for 10 min. In this work a brief introduction to ammonia aspects are presented, like its physical and chemical properties, the dangers in its manipulation, its ways of production and its sources. The application areas in which ammonia gas detection is important and needed are also referred: environmental gas analysis (e.g. intense farming), automotive-, chemical- and medical industries. In order to monitor ammonia gas in these different areas there are some requirements that must be attended. These requirements determine the choice of sensor and, therefore, several types of sensors with different characteristics were developed, like metal oxides, surface acoustic wave-, catalytic-, and optical sensors, indirect gas analyzers, and conducting polymers. All the sensors types are described, but more attention will be given to polyaniline (PANI), particularly to its characteristics, syntheses, chemical doping processes, deposition methods, transduction modes, and its adhesion to inorganic materials. Besides this, short descriptions of PANI nanostructures, the use of electrospinning in the formation of nanofibers/microfibers, and graphene and its characteristics are included. The created sensor is an instrument that tries to achieve a goal of the medical community in the control of the breath’s ammonia levels being an easy and non-invasive method for diagnostic of kidney malfunction and/or gastric ulcers. For that the device should be capable to detect different levels of ammonia gas concentrations. So, in the present work an ammonia gas sensor was developed using a conductive polymer composite which was immobilized on a carbon transducer surface. The experiments were targeted to ammonia measurements at ppb level. Ammonia gas measurements were carried out in the concentration range from 1 ppb to 500 ppb. A commercial substrate was used; screen-printed carbon electrodes. After adequate surface pre-treatment of the substrate, its electrodes were covered by a nanofibrous polymeric composite. The conducting polyaniline doped with sulfuric acid (H2SO4) was blended with reduced graphene oxide (RGO) obtained by wet chemical synthesis. This composite formed the basis for the formation of nanofibers by electrospinning. Nanofibers will increase the sensitivity of the sensing material. The electrospun PANI-RGO fibers were placed on the substrate and then dried at ambient temperature. Amperometric measurements were performed at different ammonia gas concentrations (1 to 500 ppb). The I-V characteristics were registered and some interfering gases were studied (NO2, ethanol, and acetone). The gas samples were prepared in a custom setup and were diluted with dry nitrogen gas. Electrospun nanofibers of PANI-RGO composite demonstrated an enhancement in NH3 gas detection when comparing with only electrospun PANI nanofibers. Was visible higher range of resistance at concentrations from 1 to 500 ppb. It was also observed that the sensor had stable, reproducible and recoverable properties. Moreover, it had better response and recovery times. The new sensing material of the developed sensor demonstrated to be a good candidate for ammonia gas determination.

Development of paper-based color test-strip for drug detection in aquatic environment: Application to oxytetracycline

The wide use of antibiotics in aquaculture has led to the emergence of resistant microbial species. It should be avoided/minimized by controlling the amount of drug employed in fish farming. For this purpose, the present work proposes test-strip papers aiming at the detection/semi-quantitative determination of organic drugs by visual comparison of color changes, in a similar analytical procedure to that of pH monitoring by universal pH paper. This is done by establishing suitable chemical changes upon cellulose, attributing the paper the ability to react with the organic drug and to produce a color change. Quantitative data is also enabled by taking a picture and applying a suitable mathematical treatment to the color coordinates given by the HSL system used by windows. As proof of concept, this approach was applied to oxytetracycline (OXY), one of the antibiotics frequently used in aquaculture. A bottom-up modification of paper was established, starting by the reaction of the glucose moieties on the paper with 3-triethoxysilylpropylamine (APTES). The so-formed amine layer allowed binding to a metal ion by coordination chemistry, while the metal ion reacted after with the drug to produce a colored compound. The most suitable metals to carry out such modification were selected by bulk studies, and the several stages of the paper modification were optimized to produce an intense color change against the concentration of the drug. The paper strips were applied to the analysis of spiked environmental water, allowing a quantitative determination for OXY concentrations as low as 30 ng/mL. In general, this work provided a simple, method to screen and discriminate tetracycline drugs, in aquaculture, being a promising tool for local, quick and cheap monitoring of drugs.

Sarcosine oxidase composite screen-printed electrode for sarcosine determination in biological samples

XIX Meeting of the Portuguese Electrochemical Society - XVI Iberic Meeting of Electrochemistry

Detection of cardiac biomarker proteins using a disposable based on a molecularly imprinted polymer grafted onto graphite

A low-cost disposable was developed for rapid detection of the protein biomarker myoglobin (Myo) as a model analyte. A screen printed electrode was modified with a molecularly imprinted material grafted on a graphite support and incorporated in a matrix composed of poly(vinyl chloride) and the plasticizer o-nitrophenyloctyl ether. The protein-imprinted material (PIM) was produced by growing a reticulated polymer around a protein template. This is followed by radical polymerization of 4-styrenesulfonic acid, 2-aminoethyl methacrylate hydrochloride, and ethylene glycol dimethacrylate. The polymeric layer was then covalently bound to the graphitic support, and Myo was added during the imprinting stage to act as a template. Non-imprinted control materials (CM) were also prepared by omitting the Myo template. Morphological and structural analysis of PIM and CM by FTIR, Raman, and SEM/EDC microscopies confirmed the modification of the graphite support. The analytical performance of the SPE was assessed by square wave voltammetry. The average limit of detection is 0.79 μg of Myo per mL, and the slope is −0.193 ± 0.006 μA per decade. The SPE-CM cannot detect such low levels of Myo but gives a linear response at above 7.2 μg · mL−1, with a slope of −0.719 ± 0.02 μA per decade. Interference studies with hemoglobin, bovine serum albumin, creatinine, and sodium chloride demonstrated good selectivity for Myo. The method was successfully applied to the determination of Myo urine and is conceived to be a promising tool for screening Myo in point-of-care patients with ischemia.

Protein–polyphenol interaction on silica beads for astringency tests based on eye, photography or reflectance detection modes

Astringency is an organoleptic property of beverages and food products resulting mainly from the interaction of salivary proteins with dietary polyphenols. It is of great importance to consumers, but the only effective way of measuring it involves trained sensorial panellists, providing subjective and expensive responses. Concurrent chemical evaluations try to screen food astringency, by means of polyphenol and protein precipitation procedures, but these are far from the real human astringency sensation where not all polyphenol–protein interactions lead to the occurrence of precipitate. Here, a novel chemical approach that tries to mimic protein–polyphenol interactions in the mouth is presented to evaluate astringency. A protein, acting as a salivary protein, is attached to a solid support to which the polyphenol binds (just as happens when drinking wine), with subsequent colour alteration that is fully independent from the occurrence of precipitate. Employing this simple concept, Bovine Serum Albumin (BSA) was selected as the model salivary protein and used to cover the surface of silica beads. Tannic Acid (TA), employed as the model polyphenol, was allowed to interact with the BSA on the silica support and its adsorption to the protein was detected by reaction with Fe(III) and subsequent colour development. Quantitative data of TA in the samples were extracted by colorimetric or reflectance studies over the solid materials. The analysis was done by taking a regular picture with a digital camera, opening the image file in common software and extracting the colour coordinates from HSL (Hue, Saturation, Lightness) and RGB (Red, Green, Blue) colour model systems; linear ranges were observed from 10.6 to 106.0 μmol L−1. The latter was based on the Kubelka–Munk response, showing a linear gain with concentrations from 0.3 to 10.5 μmol L−1. In either of these two approaches, semi-quantitative estimation of TA was enabled by direct eye comparison. The correlation between the levels of adsorbed TA and the astringency of beverages was tested by using the assay to check the astringency of wines and comparing these to the response of sensorial panellists. Results of the two methods correlated well. The proposed sensor has significant potential as a robust tool for the quantitative/semi-quantitative evaluation of astringency in wine.

Solid contact PVC membrane electrodes based on neutral or charged carriers for the selective reading of anionic sulfamethoxazole and their application to the analysis of aquaculture water

Sulfamethoxazole (SMX) is among the antibiotics employed in aquaculture for prophylactic and therapeutic reasons. Environmental and food spread may be prevented by controlling its levels in several stages of fish farming. The present work proposes for this purpose new SMX selective electrodes for the potentiometric determination of this sulphonamide in water. The selective membranes were made of polyvinyl chloride (PVC) with tetraphenylporphyrin manganese (III) chloride or cyclodextrin-based acting as ionophores. 2-nitrophenyl octyl ether was employed as plasticizer and tetraoctylammonium, dimethyldioctadecylammonium bromide or potassium tetrakis (4-chlorophenyl) borate was used as anionic or cationic additive. The best analytical performance was reported for ISEs of tetraphenylporphyrin manganese (III) chloride with 50% mol of potassium tetrakis (4-chlorophenyl) borate compared to ionophore. Nersntian behaviour was observed from 4.0 × 10−5 to 1.0 × 10−2 mol/L (10.0 to 2500 µg/mL), and the limit of detection was 1.2 × 10−5 mol/L (3.0 µg/mL). In general, the electrodes displayed steady potentials in the pH range of 6 to 9. Emf equilibrium was reached before 15 s in all concentration levels. The electrodes revealed good discriminating ability in environmental samples. The analytical application to contaminated waters showed recoveries from 96 to 106%.