Browsing by Issue Date, starting with "2016-09"
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- Toxic metals in indoor dust collected from houses included in the “6x60x6” Project (Covilhã, Portugal) during the cooling seasonPublication . Pastorinho, Ramiro; Lanzinha, João; Barata, Luis Taborda; Patto, Maria Da Assunção Vaz; Monteiro, Marisa Rodrigues; Nepomuceno, Miguel; Sousa, Ana Catarina AlmeidaWe spend more than 90 per cent of our daily lives indoors. Managing the indoor environment so that we feel comfortable and healthy is therefore very important. However, this management is only possible if rigorous data on both construction parameters and indoor environment exists. Moreover, the evolution of construction techniques and materials used modulates both aspects. As a consequence, it is necessary that the information obtained reflects a long period of time. That is the main driver for the project “Six by Sixty by Six” undertaken by the Civil Engineering and Architecture Department and the Faculty of Health Sciences of the University of Beira Interior. Six houses constructed in six different decades (1960’s-2010’s) were surveyed for sixty days regarding a set of parameters (e.g., temperature, humidity, CO2, CO, VOCs). Additionally, dust was collected by the vacuum cleaner bag and was analyzed for specific contaminants. This work presents the results obtained for the toxics metals mercury, arsenic, cadmium, and lead in dust samples. There is no legislation regulating maximum permissible levels for any of the studied metals in dust. A comparison with ”Portaria Nº 1450/2007” which regulates the maximum metal contents in dredged sediment that can be safely deposited in soils (here used as an action threshold) reveals that the values for As in all houses were transcended. For Cd and Hg they were only transcended in one house, whereas for lead all the values were below this threshold. Linear regression with age of construction used as independent variable revealed no relationship between this variable and metal concentrations with the exception of As (R2 adjusted= 0.41). Findings are discussed under the light of potential health outcomes upon the residents.
- Smart Textiles for Strengthening of StructuresPublication . Górski, Marcin; Krzywoń, Rafał; Dawczyński, Szymon; Szojda, Leszek; Salvado, Rita; Lopes, Catarina; Araújo, Pedro; Velez, Fernando J.; Gomes, João CastroThis paper presents results of mechanical tests on a prototype of an innovative structural strengthening in form of self-monitoring fabric. Smart textile employs carbon fibers conductivity for measuring strains while monitoring changes of electric resistance under increasing load. A general solution was tested in a series of calibrating tests on strengthening of small size concrete slabs. Promising results of simple specimen, has encouraged the research team to perform the next tests using mastered carbon fibre reinforced fabric. Main tests were performed on natural scale RC beam. Smart textile proved its efficiency in both: strengthening and monitoring of strains during load increase. New strengthening proposal was given 10% increase of loading capacity and the readings of strain changes were similar to those obtained in classical methods. In order to calibrate the prototype and to define range limits of solution usability, textile sensor was tested in areas of large deformations (timber beam) and as well as very small strains (bridge bearing block). In both cases, the prototype demonstrated excellent performance in the range of importance for structural engineering. This paper also presents an example of use of the smart strengthening in situ, in a real life conditions.
- Impact of Rural Grid-Connected Photovoltaic Generation Systems on Power QualityPublication . Pinto, Rita; Mariano, S.; Calado, M. do Rosário; Souza, José dePhotovoltaic (PV) generation systems have been increasingly used to generate electricity from renewable sources, attracting a growing interest. Recently, grid connected PV micro-generation facilities in individual homes have increased due to governmental policies as well as greater attention by industry. As low voltage (LV) distribution systems were built to make energy flow in one direction, the power feed-in of PV generation in rural low-voltage grids can influence power quality (PQ) as well as facility operation and reliability. This paper presents results on PQ analysis of a real PV generation facility connected to a rural low-voltage grid. Voltage fluctuations and voltage harmonic contents were observed. Statistical analysis shows a negative impact on PQ produced by this PV facility and also that only a small fraction of the energy available during a sunny day is converted, provoking losses of revenue and forcing the converter to work in an undesirable operating mode. We discuss the disturbances imposed upon the grid and their outcome regarding technical and economic viability of the PV system, as well as possible solutions. A low-voltage grid strengthening has been suggested and implemented. After that a new PQ analysis shows an improvement in the impact upon PQ, making this facility economically viable.
- Best practices in refrigeration applications to promote energy efficiencyPublication . Silva, Pedro Dinho da; Gaspar, Pedro Dinis; Andrade, Luís P.; Nunes, José; Domingues, C.The food and drink industry is the largest and most dynamic manufacturing sector of the European Union. With its 286,000 companies (mostly SMEs) and turnover share of 15%, it provides jobs for over 4 million people. There is an acute need to replace energy-intensive processes in this sector by new efficient ones. The major energy consumption originates from heating, cooling and drying processes, refrigeration, electrical drive systems, among others. Refrigeration of food products can account more than 50% of the energy consumption. This chapter identifies energy-saving opportunities (technological, organisational or behavioural) and describes tailored energy-saving measures. Best practices and measures for energy efficiency improvement are disclosure, which can be applied to infrastructures, cooling chambers, vapour compression refrigeration systems, compressed air systems, steam generator/hot water systems, among others. Additionally, the use of renewable energies and procedures for analysis of the electricity consumption and power management are discussed. These best practices and energy conservation measures may substantially improve the energy efficiency and competitiveness of agrifood companies and will ultimately benefit the consumers and society by reducing food price, food waste and carbon emissions.
- 3D scaffolds coated with nanofibers displaying bactericidal activity for bone tissue applicationsPublication . Sá, Kevin; Figueira, Daniela Sofia Rodrigues; Miguel, Sónia P.; Correia, Tiago R.; Silva, Abílio Manuel Pereira da; Correia, I.J.Bone-limited capacity to fully repair large defects requires the development of new implants. In this context, new approaches have been used to promote bone regeneration and also to avoid the side effects associated with the therapeutics currently used in the clinic. Herein, 3D tricalcium phosphate/alginic acid scaffolds were produced and then coated with an electrospun mesh loaded with two different antibacterial agents, silver nanoparticles, and salicylic acid. The obtained results showed that the produced scaffolds have suitable mechanical properties, swelling, biodegradation, biomineralization activity, enhanced cellular adhesion/proliferation and bactericidal activity, and features essential for bone regeneration.
- Production and characterization of polycaprolactone- hyaluronic acid/chitosan-zein electrospun bilayer nanofibrous membrane for tissue regenerationPublication . Figueira, Daniela Sofia Rodrigues; Miguel, Sónia P.; Sá, Kevin; Correia, Ilídio Joaquim SobreiraA bilayered electrospun membrane was produced in this study, using the electrospinning technique, to be applied as a skin substitute. The upper layer of the membrane was comprised by hyaluronic acid and polycaprolactone in order to provide mechanical support and also to act as a physical barrier against external threats. Chitosan and zein were used to produce the bottom layer that was loaded with salicylic acid, in order to confer anti-inflammatory and antimicrobial activity to this layer. The physicochemical properties of the membranes were determined and the obtained results showed that the produced electrospun membrane display an ideal porosity, appropriate mechanical properties, controlled water loss and a suitable salicylic acid release profile. In addition, membranes did not exhibit any toxic effects for human fibroblast cells, since cells were able to adhere, spread and proliferate. Furthermore, no biofilm formation was noticed on membranes’ surface along the experiments. In conclusion, the gathered data reveal that this electrospun membrane has suitable properties to be used as a wound dressing.
- First Flight from Europe to the South AtlanticPublication . Silva, André; Barata, Jorge M M; Morgado, Cândido M. P.; Neves, Fernando M. S. P.The History of the transatlantic flights goes back to 1919 and began with a flight performed from Newfoundland to Lisbon; two weeks later another flight was performed between Newfoundland and Ireland. On 1922, the Portuguese airmen Gago Coutinho and Sacadura Cabral crossed the South Atlantic Ocean by air in a flight performed exclusively with internal means of navigation: a new instrument that consisted in a type of sextant improved with two spirit levels to provide an artificial horizon and also with the help of a “path corrector”. Despite this journey had lasted 79 days to cross South Atlantic Ocean, their flight time was only 62:26 minutes, and they’ve flown 8,383 nautical miles, using 3 different hydroplanes christened: Lusitania, Pátria and Santa Cruz. Despite this journey had lasted 79 days, their flight time was only 62 h 26 m; they’ve flown 8,383 nautical miles using 3 different hydroplanes christened: Lusitania, Pátria and Santa Cruz. The new artificial horizon sextant had proven itself while flying over the ocean, without external references.
- The First Aerial Journey from Portugal to MacauPublication . Neves, Fernando M. S. P.; Barata, Jorge M M; Silva, AndréOn 1920, Brito Pais and Sarmento Beires tried an unsuccessful flight attempt from Amadora, Lisbon to Madeira Island onboard an airplane Breguet XIV A2, named “Cavaleiro Negro”. Despite the scarce means of navigation both navigators managed to reach Madeira, which failed to land due to dense fog. On their way back after 8 hours of flight time, they alight at the Atlantic Ocean for lack of fuel and were rescued at about 500 km from Lisbon. On 1922, Gago Coutinho and Sacadura Cabral conducted the First Aerial Cross of the South Atlantic, flying from Lisbon to Rio de Janeiro. The Portuguese Aeronautics rejoiced auspicious days that time, with its aviation pioneers trying consecutively to reach more distant places along intercontinental flights. On 1923, Gago Coutinho and Sacadura Cabral were contemplating to perform an Around the World Flight. However, Sacadura died in 1924, while piloting an airplane acquired for the circumnavigation voyage. Later on 1924 the pilots Brito Pais and Sarmento Beires idealized the conducting of an aerial flight from Lisbon to Macau as an aspiration for a future Portuguese Around the World Flight attempt: on 7 April 1924, those pilots departed from Vila Nova de Milfontes in a Breguet XIV Bn2 airplane, starting their Journey to Macau. During a flight stage on 7 May an engine failure forced them to crash the airplane at India; on 30 May, both pilots managed to continue the Voyage in a De Havilland DH9 aircraft before being forced to end their attempt in 20 June in flying over Macau. A typhoon hindered their efforts to land and the airplane was crash landed in Chinese Territory about 800 meters from the Hong Kong Border. On 25 June 1924, they were shuttled back to Macau by boat. Brito Pais, Sarmento Beires and Manuel Gouveia returned to Portugal, via North America, visiting several Portugueses nuclei at China, Japan, United States and England. They went to Portugal on 9 September, after having flown a total of 16,760 km in 117:41 h facing often extremely adverse atmospheric conditions, sandstorms and inaccurate navigation maps.
- The History of the Portuguese Aviation - A SummaryPublication . Neves, Fernando M. S. P.; Barata, Jorge M M; Silva, AndréThis article is intended as a summary of a new area of study on the History of the Portuguese Aeronautics and Aerospace and addresses issues such as: the forthcoming of the aircraft at Portugal, its military and civilian use; the scope of early days concerning Portuguese intercontinental flights and their authors; the development of air navigation devices by Portuguese inventors in the 1920s and 30s; the Aeronautics industry and the need to develop expertise in Aeronautical/Aerospace Engineering in Portugal during the centuries XX and XXI.
- Gago Coutinho and the Scientific NavigationPublication . Silva, André; Barata, Jorge M M; Neves, Fernando M. S. P.Gago Coutinho, jointly with another Portuguese aerial navigator, managed to perform the First Flight from Europe to the South Atlantic in 1922, a Journey exclusively guided by internal means of navigation. Despite Coutinho being a person with multi-purpose activity on several areas of knowledge, he became known and glorified in the World in 1922, as an air navigator, a position that he achieved due to an aerial navigation device that he also had invented. Coutinho developed a new sextant model that could be used to measure the altitude of a star (when flying overseas) without the need of the sea horizon. This new device was called precision sextant and was provided with an artificial horizon line defined with the help of a water bubble. Due to his knowledge of Navigation, Astronomy, Geography and Mathematics, Coutinho received from the Portuguese King D. Carlos I, several assignments at Africa and Asia. Gago Coutinho received several important official medals and prizes, including the Ph.D. Honoris Causa from the Universities of Lisbon and Oporto and authored several scientific publications. Coutinho received the distinct position of Admiral of the Portuguese Navy in 1958 and died in the following year.