A Methodology to Design FPGA-based PID Controllers

This paper presents a methodology to implement PID (Proportional, Integral, Derivative) controllers in FPGAs (Field-Programmable Gate Arrays) using fixed-point numerical representation. The Matlab/Simulink environment is used for modeling, simulation and evaluation the performance provided by different fixed-point representations using a given control process. A static bit-width analyzer is used to give a specialized fixed-point representation for each operand/operator in the controller system. After bit-width analysis, a VHDL represen-tation of the system is generated. Results show that the proposed methodology leads to shorten design cycles achieving important resource savings by employing specialized fixed-point repre-sentations

Estimating sheet flow velocities using quinine as a fluorescent tracer: bare, mulched, vegetated and paved surfaces

When direct flow velocity measurements are not feasible, the use of tracers can be a valuable tool. In the present study, both laboratory and field experiments were conducted to evaluate the applicability of quinine as a fluorescent tracer for estimating mean sheet flow velocities in different ambient light and surface morphology conditions. Quinine excels in low-light conditions when exposed to UVA light. This tracer was compared with dye and thermal tracers, all in liquid form. In these tracing techniques the tracers were injected into the flow, after which surface velocity was estimated by tracking the leading edge of the tracer plumes and applying a correction factor to calculate the mean velocity (in a water column). The visibility of the tracers was evaluated by measuring the relative luminance and contrast ratio of the quinine and dye tracer plumes. Results show that the quinine tracer can be used to estimate sheet flow velocities over a wide variety of soil and urban surfaces; it has better visibility in comparison to the dye tracer but, in some conditions, lower visibility than the thermal tracer. Although quinine is invisible under bright ambient light conditions, this tracer technique requires low-cost experimental setup and is useful in low-light conditions (e.g., night; twilight; shielded environments).info:eu-repo/semantics/publishedVersio

Using quinine as a fluorescent tracer to estimate overland flow velocities on bare soil: Proof of concept under controlled laboratory conditions

This study presents a tracer technique based on the fluorescent properties of quinine to help on the visualization of shallow flows and allow a quantitative measurement of overland flow velocities. Laboratory experiments were conducted to compare the traditional dye tracer and thermal tracer techniques with this novel fluorescent (quinine) tracer by injecting a quinine solution and the other tracers into shallow flowing surface water. The leading-edge tracer velocities, estimated using videos of the experiments with the quinine tracer were compared with the velocities obtained by using thermograms and real imaging videos of the dye tracers. The results show that the quinine tracer can be used to estimate both overland and rill flow velocities, since measurements are similar to those resulting from using other commonly used tracers. The main advantage of using the quinine tracer is the higher visibility of the injected tracer under ultraviolet A (UVA) light for low luminosity conditions. In addition, smaller amounts of quinine tracer are needed than for dye tracers, which lead to smaller disturbances in the flow. It requires a simple experimental setup and is non-toxic to the environment.UIDB/04292/2020info:eu-repo/semantics/publishedVersio

Sediment transport rate-based model for rainfall-induced soil erosion

http://www.sciencedirect.com/science/article/B6VCG-4TP7HC2-1/2/2a6275ceb0176f80cedfb5efe5ef248

Perceived barriers for healthy eating by university employees at the workplace

info:eu-repo/semantics/publishedVersio

Impact of a food education session on vegetables plate waste in a portuguese School Canteen

Several authors have shown that vegetables a re the most commonly wasted component in school lunches and enhance the importance of food education on topics such as food waste and vegetable consumption. The present research evaluated the efficacy of a single session of food education on vegetables waste and consumption. The data collection was focused on primary school students from a school located in Guarda district (Portugal). A vegetable selective aggregate weighing from the lunch plate was required in two distinct phases: before and after a single 30 min nutritionist’s intervention. The variables collected were the quantities of vegetables produced, leftovers and plate waste. Through these weighings, it was possible to measure the variables: distributed vegetables, consumed vegetables, vegetables waste, leftovers index, plate waste index. The use of materials such as a scale, suitable containers, gown, disposable gloves, cap and office supplies were necessary. In total during the two phases, 870 meals were evaluated. Measures of central tendency and statistical analysis tests were used. At the end of the present research, it was possible to verify significant results in the reduction of the vegetables leftovers index and in the increase in vegetable consumption per capita, through the nutritionist’s intervention. There were significant differences in the reduction of the index of vegetable leftovers and in the increase in the consumption of vegetables per capita and no significant differences in total vegetable waste. Potential causes and strategies for future research were also discussed. This study demonstrates how a nutritionist’s intervention, in a school context, could translate into behavioral change in nutrition and sustainability terms.info:eu-repo/semantics/publishedVersio

Food consumption determinants and barriers for healthy eating at the workplace: a university setting

Background: A wide variety of social, cultural and economic factors may influence dietary patterns. This work aims to identify the main determinants of food consumption and barriers for healthy eating at the workplace, in a university setting. Methods: A cross-sectional observational study was conducted with 533 participants. Data were obtained through the application of a self-administered questionnaire that included socio-demographic information, food consumption determinants and the main perceived barriers for healthy eating at the workplace. Results: The respondents identified “price” (22.5%), “meal quality” (20.7%), and “location/distance” (16.5%). For women, the determinant “availability of healthy food options” was more important than for men (p < 0.001). The food consumption determinants at the workplace most referred to by respondents were related to the nutritional value. Smell, taste, appearance and texture, and good value for money, were also considered important for choosing food at the workplace. Respondents referred to work commitments and lack of time as the main barriers for healthy eating at the workplace. Conclusions: Identification of determinants involved in food consumption, and the barriers for healthy eating, may contribute to a better definition of health promotion initiatives at the workplace aiming to improve nutritional intake.info:eu-repo/semantics/publishedVersio

Relationship of chemical structures of textile dyes on the pre-adaptation medium and the potentialities of their biodegradation by Phanerochaete chrysosporium

Azo dye derivatives of azobenzene constitute the largest group of dyes used in the textile industry and possess recalcitrant chemical groups, such as those of azo and sulphonic acid. Some microorganisms are able to degrade these aromatic compounds. In the present work, decolourisation of culture media containing azo dyes by the ligninolytic fungus Phanerochaete chrysosporium was achieved under nitrogenlimited conditions. The dyes used in the study are derivatives of meta- or para-aminosulphonic or aminobenzoic acids and include in their structures groups such as guaiacol or syringol, which are bioaccessible to the lignin degrading fungus P. chrysosporium. The aim of this study was to pre-adapt the microorganism to the structure of the dyes and to establish the relationships of the chemical structure of the dye present in the pre-adaptation medium with the chemical structure of the dye to be degraded. The azo dye used in the pre-adaptation medium that gave the best overall decolourisation performance was a meta-aminosulphonic acid and guaiacol derivative. The azo dye derivative of a meta-aminobenzoic acid and syringol showed a better performance in the decolourisation assays. Preliminary GC-MS studies indicated the formation of a nitroso substituted catechol metabolite, a precursor of aromatic ring cleavage, which was confirmed to occur by an enzymatic assay. The presence of this type of metabolite allows the establishment of a possible metabolic pathway towards mineralisation.Fundação para a Ciência e a Tecnologia (FCT) - PRAXIS XXI/BD/15878/98.Instituto de Biotecnologia e Química Fina (IBQF)

Perception of portuguese consumers regarding food labeling

Food labels are the first information tool used by consumers in the purchase and consumption of food products. Food labeling is a tool that can influence the consumers’ perception of quality and, in turn, their food choice. This study characterizes and demonstrates the importance of labeling and the degree of consumers’ perception and literacy about food labels through the application of an online questionnaire. The results obtained, in a sample of n = 467, showed that Portuguese consumers have the habit of reading the label and recognizing its importance but do not understand all the information contained in the label. They have an easier time understanding the front-of-pack labeling systems, especially those presented through symbols/colors. Thus, it demonstrates the need for greater education and literacy in the areas of food and nutrition so that through the reading and interpretation of labels, consumers can make informed food choices.info:eu-repo/semantics/publishedVersio