Percorrer por autor "Pinto, Gustavo Filipe"
A mostrar 1 - 10 de 25
Resultados por página
Opções de ordenação
- Assessment of an Innovative Way to Store Hydrogen in VehiclesPublication . Baptista, Andresa; Pinho, Carlos; Pinto, Gustavo Filipe; Ribeiro, Leonardo; Monteiro, Joaquim; Santos, TiagoThe use of hydrogen as an alternative to fossil fuels for vehicle propulsion is already a reality. However, due to its physical characteristics, storage is still a challenge. There is an innovative way, presented in this study, to store hydrogen in conventional vehicles propelled by spark-ignition reciprocating engines and fuel cells, using hydrogen as fuel; the storage of hydrogen will be at high pressure within small spheres randomly packed in a tank, like the conventional tank of fuel used nowadays in current vehicles. Therefore, the main purpose of the present study is to assess the performance of this storage system and compare it to others already applied by car manufacturers in their cars. In order to evaluate the performance of this storage system, some parameters were taken into account: The energy stored by volume and stored by weight, hydrogen leakage, and compliance with current standards. This system is safer than conventional storage systems since hydrogen is stored inside small spheres containing small amounts of hydrogen. Besides, its gravimetric energy density (GED) is threefold and the volumetric energy density (VED) is about half when compared with homologous values for conventional systems, and both exceed the targets set by the U.S. Department of Energy. Regarding the leakage of hydrogen, it complies with the European Standards, provided a suitable choice of materials and dimensions is made.
- Assessment of the Use of Solar Desalination Distillers to Produce Fresh Water in Arid AreasPublication . Monteiro, Joaquim; Baptista, Andresa; Pinto, Gustavo Filipe; Ribeiro, Leonardo; Mariano, HélderWater is an important resource for human beings, yet there are inhabited places tormented by the scarcity of it. The present study is concerned with places where, seemingly, the best way to get water is through solar distillers. These places should have, typically, high values of solar irradiation and a lack of human and economic resources to build and operate complex equipment. A set of sites scattered around the world was chosen, and then the presumed productivity and thermal efficiency that solar distillers would have if they were installed at these places was calculated. The mathematical model used with this purpose assumes steady-state operation; the values of mass of water distilled and distiller efficiency were calculated for every hour, but the results presented are annual averages. Then, an economic study was made based on local costs of construction materials for the distillers, the workforce, and the prices of water to predict the payback time of solar distillers. Finally, a study on environmental impact, particularly in terms of greenhouse gas (GHG) emissions, was made to compare reverse osmosis (RO) with solar distillation. For the sites studied, typical values of annual water output are in the range of 414 dm3/m2, for Évora, up to 696 dm3/m2, for Faya Largeau; the minimum efficiency was found for Évora, as 11.5%, and the maximum efficiency was found for Tessalit, as 15.2%. Payback times are very high, regardless of the areas of the globe where solar distillers are implanted. Regarding GHG emissions, solar distillation is preferable to RO.
- Characterization of hybrid pultruded structural products based on preformsPublication . Silva, F.J.G.; Baptista, Andresa; Pinto, Gustavo Filipe; Campilho, R.D.S.G.; Ribeiro, M.C.S.Pultrusion is a widely known technique for production of constant cross-section profiles, such as bars, L-shape or T-shape profiles, as well as structural tubes in polymer matrix composite materials. In some applications, requirements are demanding for profiles able to provide better thermal or sound insulation or needing a slightly higher moment of inertia without increasing the ratio between weight and strength. In such cases, hybrid pultruded profiles with core based on preforms are a possible solution. After obtaining prototypes according to the methodologies described in a previous work, and as a complement to that work, it is necessary to verify if the properties of these hybrid profiles correspond to the initial expectations, by performing destructive and non-destructive tests. Thus, tensile, compression and bending tests were performed, in order to verify the mechanical benefits achieved through the core introduction into the hollow profile and to analyse the added value brought by these new products. These values, once properly validated, can be added to existing databases related to structural calculation programs, enabling to get the adequate values for calculations regarding this kind of profiles. In addition, thermal and acoustic insulation tests were performed, in order to quantify the physical improvements achieved regarding these properties, which are extremely important in specific applications linked to the civil construction and public works, among many others. The cored profiles showed a strong adhesion between the profile and any kind of core tested as well as improved properties in terms of thermal insulation and moment of inertia. However, the sound insulation did not present significant improvements, probably due to GFRP profile external rigidity and consequent reflection.
- Continuous improvement in maintenance: a case study in the automotive industry involving Lean toolsPublication . Pinto, Gustavo Filipe; Silva, F.J.G.; Campilho, R.D.S.G.; Casais, R.B.; Fernandes, A.J.; Baptista, AndresaMaintenance function assumes a key role in today’s industry. The automotive industry is not an exception and there are strict rules to comply with. Indeed, the IATF 16949:2016 imposes the implementation of key performance indicator as a mean to control the overall manufacturing performance. This work presents a case study carried out in a multinational company related with the production of parts for the automotive industry where it was necessary to implement key performance indicators to comply with the IATF 16949: 2016 standard and a model was also created for the management of spare parts linked to the maintenance of existing equipment. The introduction of these changes forced the application of some Lean tools, with a view to improving procedures and information flows. The work was completed successfully, and key performance indicators were implemented, whose support data, which is now collected and calculated automatically on a routine basis, and the spare-parts management was validated with a view to optimization of warehouse space and at a conveniently low inventory level in this type of parts, without endangering critical equipment in production. The SMED methodology was applied, which allowed the setup time to be reduced by 11%, and the Lean 5S tool was used to organize the mould exchange activities. An OEE of more than 90% has been achieved.
- A critical review on the numerical simulation related to Physical Vapour DepositionPublication . Pinto, Gustavo Filipe; Silva, F.J.G.; Porteiro, J.; Míguez, J.L.; Baptista, Andresa; Fernandes, L.Physical Vapour Deposition (PVD) is a process usually used for the production of advanced coatings regarding its application in several industrial and current products, such as optical lens, moulds and dies, decorative parts or tools. This process has several variants due to its strong evolution along the last decades. The process is commonly assisted by plasma, creating a particular low pressure and medium temperature atmosphere, which is responsible for the transition of atomic particles between the target and the parts to be coated into a vacuum reactor. Several parameters are directly affecting the deposition, namely the substrate temperature, pressure inside the reactor, assisting gases used, type of current, power supply, bias, substrate and target materials, samples holder and corresponding rotation, deposition time, among others. Many mathematical models have been developed in order to allow the generation of numerical simulation applications, trying to combine parameters and expect the corresponding results. Numerical simulation applications were created around the mathematical models previously developed, which can play an important role in the prediction of the coating properties and structure. This paper intends to describe the numerical simulation evolution in the last years, namely the use of Finite Elements Method (FEM) and Computational Fluid Dynamics (CFD).
- Experimental study on the wear evolution of different PVD coated tools under milling operations of LDX2101 duplex stainless steelPublication . Sousa, Vitor F. C.; Silva, Francisco J. G.; Alexandre, Ricardo; Fecheira, José S.; Pinto, Gustavo Filipe; Baptista, AndresaDuplex stainless steels are being used on applications that require, especially, high corrosion resistance and overall good mechanical properties, such as the naval and oil-gas exploration industry. The components employed in these industries are usually obtained by machining, however, these alloys have low machinability when compared to conventional stainless steels. In this work, a study of the wear developed when milling duplex stainless-steel, LDX 2101, is going to be presented and evaluated, employing four types of milling tools with different geometries and coatings, while studying the influence of feed rate and cutting length in the wear of these tools. Tools used have been provided with two and four flutes, as well as three different coatings, namely: TiAlN, TiAlSiN and AlCrN. The cutting behavior of these tools was analyzed; data relative to the cutting forces developed during the process were obtained; and roughness measurements of the machined surfaces were executed. The tools were then submitted to scanning electron microscope (SEM) analysis, enabling the identification of the wear mechanisms that tools were subjected to when machining this material, furthermore, the early stages of these mechanisms were also identified. All this work was done with the goal of relating the machining parameters and cutting force values obtained, identifying, and discussing the wear patterns that were observed in the coating and tools after the milling tests, providing further information on the machining of these alloys.
- Exploring the use of quick response codes: accessing videos in the laboratoryPublication . Duarte, Marina; Baptista, Andresa; Pinto, Gustavo FilipeBringing the digital world and “digital natives” to hands-on engineering laboratory classes can be a challenge and an opportunity. Videos can be used, but is important that students know exactly what video to watch for each apparatus. That is why the possibility of accessing videos with QR codes is essential to build a bridge from concrete to digital content. The aim of this research is to evaluate the importance undergraduate engineering students attribute to instructional videos that explain the operating procedure of laboratory apparatus, and their reaction to the possibility of accessing them with quick response (QR) codes. Results show students attributed some importance to the videos and the QR codes in the laboratory are very helpful as means to quickly and easily access the videos.
- How to Become a Manufacturing Cell Fully-Automated Without Robots: Case-Study in the Automotive Components IndustryPublication . Silva, F.J.G.; Pinto, Gustavo Filipe; Baptista, Andresa; Campilho, R.D.S.G.; Araújo, WProductivity is a key factor for companies manufacturing parts and sets to the automotive industry. Automation plays an important role in this matter, allowing development of entire manufacturing cells without the direct need of workers. Even in countries where the labour cost is relatively low, it becomes necessary to improve the level of automation applied to manufacture cells and reduce the dependence of the human labour unpredictability, also increasing the quality and reducing the costs. This case study was developed based on an industrial request in order to improve a semi-automatic cell devoted to seat suspension mat manufacturing. The original cell allows several automatic operations but it needs two workers for two specific operations not considered in the initial design. Thus, new concepts of wire feeding and manipulation were developed in order to allow a better material flow throughout the cell. The new cell was designed and built with success, allowing obtain a fully-automated system, which leads to a better productivity and reliability of the manufacturing process.
- Improving the Cut Surface Quality by Optimizing Parameters in the Fibre Laser Cutting ProcessPublication . Amaral, I.; Silva, F.J.G.; Pinto, Gustavo Filipe; Campilho, R.D.S.G.; Gouveia, R.M.One of the main problems with laser cutting equipment is related to the wrong setting of cutting parameters. The mismatching of these parameters leads to a loss of cut surface quality, which is hardly re-established. This loss of quality is usually related to a burr problem. Thus, this study is aimed to improve and optimize this process using a fibre laser equipment. Three important laser cutting parameters were studied in order to investigate their importance in the cut surface quality: radiation power, cutting speed and gas pressure. The different values were performed cutting a stainless steel AISI 316L and a cold rolled steel St12. Metallographic and cut surface analysis, burr and roughness measurements were carried out, supported by a Scanning Electron Microscopy and profilometry. Through the Taguchi statistical analysis model, it is possible to indicate the best set of laser cutting parameters. It was verified that the values recommended by the equipment manufacturer can be optimized, being possible to use less radiation power in the laser beam with greater speed of cut, providing a better cut surface quality, improving and optimizing the entire process.
- Influence of the natural additive on natural fiber reinforced thermoplastic compositePublication . Selvaraj, D.K.; Silva, F.J.G.; Campilho, R.D.S.G.; Baptista, Andresa; Pinto, Gustavo FilipeComposite materials have a wide range of application in various domains. The fact behind using composite materials is that they give the same almost strength as metal parts in presenting lesser weight. However, the plastic parts are non-biodegradable, and they lead to the polluted environment during the disposal after end-of-life of a particular part. Nowadays natural and easily recyclable composites were preferred due to environmental concerns. The major disadvantage of using natural fibre composites is that they have low strength compared to conventional glass or carbon reinforced composite. To enhance the strength of Natural-Fiber-Reinforced Plastics (NFRP) various techniques have been followed (Chemical treatment of the fibre, post-curing of the composites, sandwiching the composite, adding additives/fillers to the matrix) based on the feasibility and application of the composites. Among those techniques, adding additives to the matrix is one of the simple and effective ways to enhance the properties of the composite. A natural additive is developed in concern to the environmental impact of the composite. Two different types of the composite laminate were manufactured. One is with additive and one is without the additive. It is necessary to validate the strength of the composite with and without the additives by mechanical testing. Thus, tensile, flexural and moisture absorption tests were performed to verify the mechanical property enhancement achieved due to the use of additives. These tests help in characterizing the material to specific applications. The composite with the natural additive showed better mechanical properties. However, the moisture absorption tendency of the composite is increased as well, mainly due to the presence of additives on the surface of the composite along with the matrix.
- «
- 1 (current)
- 2
- 3
- »