ESAV - DIA - Resumos de eventos científicos não indexados à WoS/Scopus
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- Estudo experimental e numérico do escoamento de um jacto plano originado por um dispositivo de cortina de arPublication . Goncalves, J. C.; Costa, José; Figueiredo, A. Rui; Lopes, AntónioNos domínios comercial ou industrial, são muito utilizadas barreiras aerodinâmicas – designadas por cortinas de ar – para confinar ambientes específicos. Neste trabalho apresenta-se o estudo experimental do jacto originado por um equipamento de cortina de ar. Recorrendo à Mecânica de Fluidos Computacional (CFD, foi também realizado um estudo numérico - 3D. Os resultados obtidos por ambas as vias, experimental e numérica, permitiram a caracterização detalhada do escoamento do jacto, sendo coerentes com o esperado para o problema físico em estudo, e coerentes entre si. Um dos aspectos interessantes observados nos ensaios experimentais, foi que o nível de turbulência inicial do jacto se situou sempre abaixo dos 5%, para as diferentes velocidades impostas ao jacto, o que confirma um bom projecto do bocal de descarga
- A Study on the Sealing Efficiency of Air Curtains: 2D and 3D ApproachesPublication . Goncalves, J. C.; Costa, J.; Figueiredo, R.; Lopes, A.In industrial refrigerated spaces, such as retail stores, where sometimes doors must be open for long periods, the infiltration loads can represent more than half of the total refrigeration load. The use of air curtains can significantly reduce the air infiltration through doorways and, at the same time, it allows the free access by persons and equipment [1]. Besides the experimental research, computational fluid dynamics (CFD) has been commonly used, either adopting a two dimensional (2D) approach [1] or, more recently, through a three-dimensional (3D) perspective [2,3]. This work presents a numerical and experimental study on the performance of air curtain devices in the aerodynamic sealing of access doors of refrigerated spaces. For this propose, a 3D numerical model was developed aiming at the simulation of the turbulent non-isothermal airflow generated by the air curtain since the moment the door is opened. The calculation domain represents a laboratory scale model consisting of two similar adjacent rooms connected by a doorway over which the air curtain device is installed. One of these rooms represents a refrigerated chamber and the other, the outdoor environment. The numerical study was carried out using a commercial CFD code (ANSYS-CFX) and the turbulence effects were approached by k-_SST turbulent model. In the experimental study, the tracer gas technique was used to estimate the air exchange rate through the doorway in the initial period of the transient process and consequently assess the sealing effect obtained with the air curtain device operating at different jet velocities. The numerical results show that the air curtain simulated is appropriate to protect the doorway in its whole width, and a good agreement is verified with the experimental measurements. Results of a simplified 2D approach are also shown and compared with the 3D simulation
- Development and Characterization of Wheat Bread with Lupin FlourPublication . Correia, Paula; Gonzaga, Marta; Batista, Luís; Beirão-Costa, Luísa; Guiné, RaquelThe purpose of the present work was to develop an innovative food product with good textural and sensorial characteristics. The product, a new type of bread, was prepared with wheat (90%) and lupin (10%) flours, without the addition of any conservatives. Several experiences were also done to find the most appropriate proportion of lupin flour. The optimized product was characterized considering the rheological, physical-chemical and sensorial properties. The water absorption of wheat flour with 10% of lupin was higher than that of the normal wheat flours, and Wheat Ceres flour presented the lower value, with lower dough development time and high stability time. The breads presented low moisture but a considerable water activity. The density of bread decreased with the introduction of lupin flour. The breads were quite white, and during storage the colour parameters decreased. The lupin flour clearly increased the number of alveolus, but the total area increased significantly just for the Wheat Cerealis bread. The addition of lupin flour increased the hardness and chewiness of breads, but the elasticity did not vary significantly. Lupin bread was sensorially similar to wheat bread produced with WCerealis flour, and the main differences are the crust rugosity, colour and alveolus characteristics.
- Contribution for Rural Development through Training in Organic FarmingPublication . Guiné, Raquel; Costa, Daniela; Correia, Paula; Castro, Moisés; Guerra, Luís; Costa, Cristina Amaro DaThe aim of this work was to characterize a potential target group of people interested in participating into a training program in organic farming in the context of mobile-learning. The information sought addressed in particular, but not exclusively, possible contents, formats and forms of evaluation that will contribute to define the course objectives and curriculum, as well as to ensure that the course meets the needs of the learners and their preferences. The sample was selected among different European countries. The questionnaires were delivered electronically for answering on-line and in the end 135 consented valid questionnaires were obtained. The results allowed characterizing the target group and identifying their training needs and preferences towards m- learning formats, giving valuable tools to design the training offer
- Statistical Analysis of the Factors that Influence the Properties of Blueberries from Cultivar BluecropPublication . Guiné, Raquel; Matos, Susana; Costa, Daniela; Gonçalves, FernandoBecause blueberries are worldwide recognized as a good source of beneficial components, their consumption has increased in the past decades, and so have the scientific works about their properties. Hence, this work was undertaken to evaluate the effect of some production and conservation factors on the properties of blueberries from cultivar Bluecrop. The physical and chemical analyses were done according to established methodologies and then all data was treated using software SPSS for assessment of the possible differences among the factors investigated and/or the correlations between the variables at study. The results showed that location of production influenced some of the berries properties (caliber, sugars, antioxidant activity, color and texture) and that the age of the bushes was correlated with moisture, sugars and acidity, as well as lightness. On the other hand, altitude of the farm only was correlated to sugar content. With regards to conservation, it influenced only anthocyanins content and DPPH antioxidant activity. Finally, the type of extract and the order of extraction had a pronounced influence on all the phenolic properties evaluated.
- Empirical correlation to estimate the optimum jet velocity of an air curtainPublication . Goncalves, J. C.; Costa, José; Figueiredo, A. Rui; Lopes, AntónioThis paper presents the results of a parametric study to quantify the influence of some thermal and geometrical parameters (door height) on the performance of an Air Curtain Device (ACD). The experimental facility consists of two similar adjacent rooms connected by a door over which the ACD device was installed. The tracer gas technique was used to calculate the sealing effect achieved with the air curtain at different jet velocities. Using a commercial CFD software, a numerical study was also performed to simulate the heat and mass transfer phenomena, as well as the aerodynamic sealing efficiency. A good agreement was observed between experimental and numerical results, showing that the optimum discharge velocity of the ACD air jet increases almost linearly with the door height, as well as with the temperature difference between both sides of the air curtain. It was possible to establish an empirical correlation that predicts reasonably well the optimum discharge jet velocity of a vertical air curtain device, depending on the temperature difference and the doorway height. An electronic device can be included in the ACD enabling the automatic adjustment of the air curtain jet velocity based this correlation, in order to continuously operate close to maximum sealing efficiency.
- Study of total phenolic composition and antioxidant activity of fresh cheese with red fruitsPublication . Gonçalves, Fernando; Leitão, Soraia; Correia, Paula; Guiné, RaquelThe dietary guidelines worldwide recommend the intake of vegetables and fruits like berries, in order to provide their benefits. Moreover dairy products could be beneficial to human health, as source of bioactive compounds. Berry fruits are considered to be a good source of natural phenolic compounds which are known for their high antioxidant activity. The main objective of this work was to quantify the total phenolic compounds and antioxidant activity of new products based on cheese enriched with red fruits. For that, fresh cheeses enriched with red fruits (blueberry or raspberry) were produced. Extracts of methanol and ethanol:water were obtained in order to determine phenolic compounds and antioxidant activity. The results obtained showed that for all cheeses studied the amount of phenolic compounds quantified was higher in the methanolic extracts than in the ethanol:water extracts. However, with regards to the antioxidant activity, it was also higher for the extracts of methanol when the DPPH method was used but lower when the ABTS method was used. Comparing the fruits, the blueberries increased more the phenolic compounds and antioxidant activity when compared with raspberries. It was concluded that the addition of red fruits resulted in cheeses with higher levels of phenolic compounds and antioxidant activity improving their potential health benefits.
- Variação das propriedades físicas de frutos com a secagem e estudo cinéticoPublication . Guiné, Raquel; Sousa, Cristina; Carmo, Jéssica; Ferreira, Susana; Pereira, Carla; Marques, IvoneNo presente trabalho foi estudada a secagem de duas frutas (kiwi e maçã) no que respeita às propriedades físicas de textura e cor e ainda foi avaliada a cinética de secagem com ajuste a modelos de camada fina. Para a secagem usou-se uma câmara de convecção a 80 ºC e com velocidade do ar de 0.5 m/s. Antes e depois da secagem os frutos foram analisados no que respeita à sua cor e textura, por serem propriedades que são bastante afetadas por este tipo de processo térmico. A medição da cor fez-se com um colorímetro nas coordenadas CIELab e para a análise do perfil de textura utilizou-se um texturómetro equipado com uma sonda de 75 mm. Os resultados mostraram que a secagem originou diferenças de cor muito assinaláveis em ambos os casos, com valores de E de 8.6 e 10.7, respetivamente para o kiwi e para a maçã. No caso do kiwi, verificaram-se diferenças importantes entre a polpa, a parte interna do fruto e ainda as sementes (L* a variar entre 42 e 62, a* entre -8 e -1, b* entre 17 e 33). No que respeita à textura, a secagem produziu alterações marcantes na estrutura dos frutos, com diminuição da dureza (40-62%) e mastigabilidade (13-42%) contrabalançadas por um aumento na resiliência (226-131%), coesividade (17-25%) e elasticidade (20-23%). Em relação à cinética, os dois frutos testados apresentaram um comportamento semelhante, tendo demorado 2,5 horas a atingir um conteúdo de humidade de cerca de 20%. De entre os dois modelos testados, o que se revelou mais ajustado aos dados experimentais foi o modelo de Wang & Singh, com coeficientes de correlação de 0.998 e 0.999, respetivamente para o kiwi e a maçã.
- Knowledge of heatlh effects of dietary fiber among nurses and the general population in croatia: comparative analysisPublication . Ljubicic, Marija; Saric, Marijana; Curin, Katja; Guiné, RaquelINTRODUCTION: Nurses play diverse roles in educating patients about healthy diet and in promoting healthy eating habits, through their conversations with patients and families and through their work providing enteral and parenteral feeding to critically ill patients. Given the position of nurses as key providers of dietary guidance, and given the health benefits of dietary fibre, we wanted to assess the level of fibre-related knowledge among nurses in Croatia. OBJECTIVES: The primary objective of this cross sectional study was to compare knowledge between nurses and general population from Croatia about the health importance of consuming dietary fibre. METHODS: Knowledge of 369 nurses and 727 residents from the general population about fibre was assessed using a validated survey developed by the CI&DETS Polytechnic Institute, Viseu, Portugal. Differences between nurses and general population were assessed for significance using the Mann-Whitney U test and Kruskal-Wallis test, while associations between study variables and knowledge were explored using Spearman rank correlation coefficients. RESULTS: The level of knowledge among nurses and the general population in Croatia about dietary fibre varies from «undecided» to «partial knowledge». No association was observed between nurse education level and either general knowledge about fibre or knowledge about the health benefits of fibre intake. No significant differences were observed between nurses and general population in general knowledge (p = 0.894) or in health-related knowledge (p = 0.578). CONCLUSION: Results suggest the need for updating and expanding nursing curricula. The similar level of knowledge between nurses and the general population about dietary fibre indicates the need to strengthen nurse education and training in the areas of diet and diet therapy in Croatia. Given the role of nurse as diet educators and advisors, this may help improve the quality of health care.
- Effect of cardoon genotype on colour and texture of Serra da Estrela CheesePublication . Correia, Ana Cristina; Guiné, Raquel; Ferreira, Ana; Matias, JoséThe objectives of this study were to evaluate the colour and the textural properties in Serra da Estrela Cheeses produced with different cardoon genotypes. The cheeses were produced with ewe´s raw milk, following the procedures adopted for the Serra da Estrela cheese with Protected Designation of Origin (PDO). The maturation time was 45 days. The results showed that lightness was very similar for the five samples evaluated (varying from 58.8 to 61.1), just like greenness (-3.2 to -2.5) and yellowness (18.8 to 20.7). Hence it was not possible to clearly identify particular colour characteristics associated with a certain cardoon genotype. However, regarding texture, the results were quite different among the cheese samples studied. Crust firmness varied from 3.9 to 5.4 N, flesh firmness from 1.0 to 1.4 N, stickiness from -2.0 to -1.1 N and adhesiveness from -15.1 to -8.3 N.s. The cardoon ecotype 1M allowed obtaining cheeses with firmer crust and flesh, while being stickier and more adhesive. As a conclusion, it was possible to verify that the genotype variability in the cardoon used for the production of Serra da Estrela cheese can in fact influence some of the product’s characteristics, and particularly the texture.