Candida Maria dos Santos Pereira Malca
@isec.pt
Polytechnic Institute of Coimbra
Coimbra Institute of Engineering
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Z. Marciniak, R. Branco, W. Macek, M. Dobrzyński, and C. Malça
Elsevier BV
José Camacho, Rui F. Martins, Ricardo Branco, António Raimundo, and Cândida Malça
Wiley
AbstractSelective laser melting (SLM) is an additive manufacturing powder‐bed fusion process that allows producing complex metallic parts with a relative density of up to 99.9%. Nevertheless, the mechanical properties of these components depend on numerous process variables, and there is a lack of systematic studies focused on SLM stainless steels. In the work herein presented, three specific printing strategies were X‐Y patterned to manufacture Compact Tension specimens transversally, longitudinally, or chess‐oriented, without any post‐processing heat treatment. The specimens were made of AISI 316L austenitic stainless steel. Thereafter, fatigue crack growth rate (FCGR) tests were carried out at room temperature, at constant amplitude loading (R = 0.2), to determine the fatigue crack propagation constants of the Paris Law associated with each print strategy. It was possible to conclude that transversal additively manufactured specimens showed the lowest FCGRs, and all results were well below the fatigue design curve given in ASME BPVC, Section XI.
Hugo Neves, Arménio Cruz, Rafael A. Bernardes, Remy Cardoso, Mónica Pimentel, Filipa Margarida Duque, Eliana Lopes, Daniela Veiga, Cândida Malça, Rúben Durães,et al.
MDPI AG
Bedridden patients risk presenting several problems caused by prolonged immobility, leading to a long recovery process. There is thus a need to develop solutions that ensure the implementation of physical rehabilitation programs in a controlled and interactive way. In this context, the ABLEFIT project aims to develop a medical device to physically rehabilitate bedridden patients with prolonged immobility. A partnership was established between the school of nursing, business enterprises and an engineering institute to develop a prototype. After creating the prototype, a pre-clinical experimental usability study was created using the user-centred multi-method approach (User and Human-Centered Design) to assess the device’s functionality, ergonomics and safety. The pre-clinical stage was initiated with a sample of 12 health professionals (that manipulated the device’s functionalities) and 10 end-users (who used the device). During the pre-clinical stage, the need to incorporate in the final version joint stabilizers was observed. Another important finding was the importance of the continuous monitorization of vital signs on Ablefit, namely, heart rate and SPO2. Therefore, the development of the Ablefit system allows the monitoring of a set of variables and conditions inherent to immobility. At the same time, this device will be a dynamic solution (using gamification and simulation technologies) by generating personalized rehabilitation plans.
R. Bernardes, V. Parola, R. Cardoso, H. Neves, A. Cruz, W. Xavier, R. Durães, and C. Malça
World Scientific and Engineering Academy and Society (WSEAS)
Commercially available technical solutions used in physical rehabilitation processes have not responded effectively to the crucial needs of customized rehabilitation programs. As such, a partnership between a nursing school, technological enterprises – ORTHOS XXI and WISEWARE - and engineering institutes was established to implement a project entitled ABLEFIT to overcome the identified lack of technical solutions in the market. ABLEFIT has the main purpose of making available a rehabilitation device in the market that ensures the implementation of physical rehabilitation programs in a controlled and interactive way so that patients can regain their physical, psychological, and social functions as soon as possible. The loss of these capabilities is closely related to Prolonged Immobility Syndrome (PIS), being the morbidity and mortality associated with the complications resulting from prolonged inactivity or even a sedentary lifestyle seen both in the elderly population and in adults and young people with some type of restriction of mobility or disability. This paper describes the optimization process of the ABLEFIT device based on the pre-clinical trials performed. The optimization process starts with the design of an initial prototype, followed by the construction of a second prototype, and finally the planning of an additional iteration, which will involve the construction of a third prototype that will look identical to the version that will be available in the market. The two iterations of the ABLEFIT prototype device developed up to now provide undeniably an advanced solution to support physical rehabilitation, since they combine a biomechanical system to aid physical exercise, in passive and active modes, in bed and a wheelchair, with a control system for monitoring and storing biofeedback variables and motivational stimulus through interaction with gamification. The ABLEFIT device significantly contributes to the reduction of morbidity and mortality associated with complications resulting from prolonged inactivity.
T. Ribeiro, L. Roseiro, M. Silva, F. Santos, R. Bernardes, R. Cardoso, V. Parola, H. Neves, A. Cruz, W. Xavier,et al.
Springer Nature Switzerland
Remy Cardoso, Vitor Parola, Hugo Neves, Rafael A. Bernardes, Filipa Margarida Duque, Carla A. Mendes, Mónica Pimentel, Pedro Caetano, Fernando Petronilho, Carlos Albuquerque,et al.
MDPI AG
Bedridden patients usually stay in bed for long periods, presenting several problems caused by immobility, leading to a long recovery process. Thus, identifying physical rehabilitation programs for bedridden patients with prolonged immobility requires urgent research. Therefore, this scoping review aimed to map existing physical rehabilitation programs for bedridden patients with prolonged immobility, the rehabilitation domains, the devices used, the parameters accessed, and the context in which these programs were performed. This scoping review, guided by the Joanna Briggs Institute’s (JBI) methodology and conducted in different databases (including grey literature), identified 475 articles, of which 27 were included in this review. The observed contexts included research institutes, hospitals, rehabilitation units, nursing homes, long-term units, and palliative care units. Most of the programs were directed to the musculoskeletal domain, predominantly toward the lower limbs. The devices used included lower limb mobilization, electrical stimulation, inclined planes, and cycle ergometers. Most of the evaluated parameters were musculoskeletal, cardiorespiratory, or vital signs. The variability of the programs, domains, devices and parameters found in this scoping review revealed no uniformity, a consequence of the personalization and individualization of care, which makes the development of a standard intervention program challenging.
R. Branco, J.D. Costa, P.A. Prates, F. Berto, C. Pereira, and A. Mateus
Elsevier BV
José F. Garcias, Rui F. Martins, Ricardo Branco, Zbigniew Marciniak, Wojciech Macek, Cândida Pereira, and Cyril Santos
Wiley
Mariana Vallejo, Rachel Cordeiro, Paulo A. N. Dias, Carla Moura, Marta Henriques, Inês J. Seabra, Cândida Maria Malça, and Pedro Morouço
Springer Science and Business Media LLC
AbstractConsidering the expected increasing demand for cellulose fibers in the near future and that its major source is wood pulp, alternative sources such as vegetable wastes from agricultural activities and agro-food industries are currently being sought to prevent deforestation. In the present study, cellulose was successfully isolated from six agroindustrial residues: corncob, corn husk, grape stalk, pomegranate peel, marc of strawberry-tree fruit and fava pod. Cellulose fibers were characterized by Fourier-transform infrared spectroscopy, thermogravimetric analysis, stereomicroscopy and scanning electron microscopy (SEM). Despite the evident morphological differences among the extracted celluloses, results revealed similar compositional and thermal properties with the wood-derived commercial microcrystalline cellulose used as a control. Trace amounts of lignin or hemicellulose were detected in all cellulose samples, with the exception of corncob cellulose, that exhibited the greatest extraction yield (26%) and morphological similarities to wood-derived microcrystalline cellulose, visible through SEM. Furthermore, corncob cellulose was found to have thermal properties (TOnset of 307.17 °C, TD of 330.31 °C, and ΔH of 306.04 kJ/kg) suitable for biomedical applications.
Vitor Parola, Hugo Neves, Filipa Margarida Duque, Rafael A. Bernardes, Remy Cardoso, Carla A. Mendes, Liliana B. Sousa, Paulo Santos-Costa, Cândida Malça, Rúben Durães,et al.
MDPI AG
Bedridden patients usually stay in bed for long periods, presenting several motor problems caused by immobility, such as reductions in muscle mass, bone mineral density and physical impairment, resulting in a long recovery process. Thus, identifying physical rehabilitation programs for bedridden patients with prolonged immobility is a matter of urgent research for a solution that will help health professionals and stakeholders to develop more adjusted programs and identify possible gaps. To date, no previous scoping reviews addressing this purpose have been found. This scoping review will be guided by the Joanna Briggs Institute (JBI) methodology, will focus on physical rehabilitation programs for bedridden patients with prolonged immobility and aims to map the programs, the devices used, and the parameters assessed. A relevant set of electronic databases and grey literature will be searched. Data extraction will be conducted using a tool developed by the research team that will address the review objectives and questions. Data synthesis will be presented in tabular form and a narrative summary aligned with the review’s objective. This scoping review will contribute to the improvement of clinical practice, identifying key challenges that might justify the need to develop new programs suitable in clinical and organizational contexts.
Wojciech Macek, Ricardo Branco, José Domingos Costa, and Cândida Pereira
Elsevier BV
Jorge Cunha, Artur Mateus, Cândida Malça, José Costa, and Ricardo Branco
Springer International Publishing
F. Nogueira, J. Cunha, A. Mateus, C. Malça, J.D. Costa, and R. Branco
Elsevier BV
Abstract This paper aims at studying the cyclic plastic behaviour of the 7075-T651 aluminium alloy under fully-reversed strain-controlled conditions. Tests are conducted under strain-control mode, at room temperature, in a conventional servo-hydraulic machine, from smooth samples, using the single step method, with strain amplitudes (Δe/2) in the range ±0.5 to ±2.75%. This material has exhibited a mixed behaviour, i.e. cyclic strain-hardens at higher strain amplitudes (Δe/2/>1.1%) and cyclic strain-softens at lower strain amplitudes (Δe/2
Rosana Silva, Filipa Couto, Maria Almeida, Cândida Malça, Pedro Parreira, João Apóstolo, and Arménio Cruz
Health Sciences Research Unit: Nursing
Background: Aging is associated with acute and chronic problems that interfere with older adults’ mobility and independence. There are several types of walkers available in the market with different functional performance profiles of older people which aim to compensate for physical limitations and prevent falls. Objective: To compare the functional performance profile of institutionalized older adults taking into account the total time, gait speed, heart rate variability, and energy cost during the Expanded Timed Get-up-and-Go test using three types of walkers: fixed, two-wheeled, and four-wheeled walkers. Methodology: One-group pretest and posttest quasi-experimental study in a convenience sample of 40 institutionalized older people. Results: Significant differences were found in the total time (X2 = 15.65; p < 0.001) and gait speed (X2 = 15.80, p < 0.001). Conclusion: There is no unique ideal solution among the types of walkers analyzed in this study, thus a tailored solution is desirable to meet institutionalized older adults’ characteristics and specific needs.
Miguel Reis Silva, António M. Pereira, Nuno Alves, Gonçalo Mateus, Artur Mateus, and Cândida Malça
MDPI AG
This work presents an innovative system that allows the oriented deposition of continuous fibers or long fibers, pre-impregnated or not, in a thermoplastic matrix. This system is used in an integrated way with the filamentary fusion additive manufacturing technology and allows a localized and oriented reinforcement of polymer components for advanced engineering applications at a low cost. To demonstrate the capabilities of the developed system, composite components of thermoplastic matrix (polyamide) reinforced with pre-impregnated long carbon fiber (carbon + polyamide), 1 K and 3 K, were processed and their tensile and flexural strength evaluated. It was demonstrated that the tensile strength value depends on the density of carbon fibers present in the composite, and that with the passage of 2 to 4 layers of fibers, an increase in breaking strength was obtained of about 366% and 325% for the 3 K and 1 K yarns, respectively. The increase of the fiber yarn diameter leads to higher values of tensile strength of the composite. The obtained standard deviation reveals that the deposition process gives rise to components with anisotropic mechanical properties and the need to optimize the processing parameters, especially those that lead to an increase in adhesion between deposited layers.
Stephane Lopes, Lúcia Filipe, Rosana Silva, Arménio Cruz, Pedro Parreira, Filipa Couto, Rafael Bernardes, João Apóstolo, Luís Roseiro, and Cândida Malça
MDPI AG
Background: The ageing process involves a natural degeneration of physiological function and can imply life constraints, namely during activities of daily life (ADL). Walking can be strongly affected by strength, gait, and balance changes, which affect quality of life. The quality of life of the older adult is associated with available solutions that contribute to an active and safe ageing process. Most of these solutions involve technical aids that should be adapted to older adults’ conditions. Aim: To identify the advantages and disadvantages of two-wheeled walkers and of two different self-locking systems designed and developed by the authors. Methods: Two studies were performed based on the possible walker combinations used, using a walker with no wheels (classic fixed walker), a two-wheeled walker with self-locking mechanism made of gears and a spring (Approach 1), and a two-wheeled walker with a self-locking mechanism which uses a single spring (Approach 2). These combinations were tested in two quasi-experimental studies with pre–post test design. Results: No significant differences in duration, gait speed, and Expanded Timed Get Up and Go (ETGUG) were found between the walkers, but there was a marginally significant difference in Physiological Cost Index (PCIs), which means that the energetic cost with Approach 1 was greater than that with Approach 2. Users reported a feeling of insecurity and more weight, although no significant differences were observed and they were found to be equivalent in terms of safety. Study 2 found an improvement in duration and gait speed in the ETGUG between the different types of self-locking systems. Conclusions: The PCI is higher in the two-wheeled walker models and with the self-locking mechanism. Approach 2 did not show better conditions of use than the other two walkers, and participants did not highlight its braking system. Although safety is similar among the three walkers, further studies are needed, and the braking system of the two-wheeled walker needs to be improved (Approach 2).
C. Malça, M. Sena, C. Santos, A. Mateus, and Nuno Alves
Author(s)
The plastic injection molding industries is nowadays one of the strongest Portuguese industries and internationally known for their good quality products. Currently an injection mold is a solid, which is heavy and expensive to produce structure due to the use of conventional subtraction material processes. The need to produce more parts with high quality in a short period of time and at a lower cost requires the continuous development on geometries, materials and manufacturing processes of injection molds. The optimization of mold cooling processing can undoubtedly lead to a reduction of the effective total time of the injection process, enabling a shorter manufacturing time, which leads to a reduction of production costs. Combining the requirements of injection mold production with the advantages of Additive Manufacturing (AM) technologies, the Selective Laser Melting (SLM) emerges as a quicker and sustainable alternative to the construction of these structures. In this work two types of cellular internal topologies - hexagonal and cub-octahedral – to be manufacturing by SLM were generated and their mechanical and thermal behaviors numerically evaluated through compression and thermal analyses. Numerical simulation results demonstrated that the hexagonal cellular internal topology provides a higher mechanical strength when compared to the cub-octahedral cellular structure while the thermal analysis shows that cub-octahedral topology is more efficient for heat dissipation.The plastic injection molding industries is nowadays one of the strongest Portuguese industries and internationally known for their good quality products. Currently an injection mold is a solid, which is heavy and expensive to produce structure due to the use of conventional subtraction material processes. The need to produce more parts with high quality in a short period of time and at a lower cost requires the continuous development on geometries, materials and manufacturing processes of injection molds. The optimization of mold cooling processing can undoubtedly lead to a reduction of the effective total time of the injection process, enabling a shorter manufacturing time, which leads to a reduction of production costs. Combining the requirements of injection mold production with the advantages of Additive Manufacturing (AM) technologies, the Selective Laser Melting (SLM) emerges as a quicker and sustainable alternative to the construction of these structures. In this work two types of cellular interna...
C. Malca, C. Santos, M. Sena, and A. Mateus
Elsevier BV
Abstract Using selective laser melting (SLM) is possible to manufacture molds with cellular internal structures with different porosity degree. Furthermore, internal geometry design can be improved as a function of the desired structural and thermal stress solicitations. In this work two types of cellular internal structures – hexagonal and cub-octahedral – were developed and manufactured using the SLM process. These topologies were generated with the purpose of creating a high degree of internal porosity and getting satisfactory results in terms of thermal and mechanical behavior when compared with similar dimensional bulk structures. The mechanical and thermal behaviors of each cellular topology were evaluated numerically and experimentally through compression and thermal tests. From numeric and experimental results, it can be concluded that hexagonal cellular internal topology provides a higher mechanical strength when compared to the cub-octahedral cellular structure while the thermal analysis shows that cub-octahedral topology is more efficient for heat dissipation. Both cellular topologies have demonstrated, however, to be appropriate for use in injection mold structures. In addition, the use of these cellular topologies provides light weight structuring with an approximate 58% weight reduction, which represents a considerable saving of material total cost to manufacturing of an injection mold.
C. Santos, A. Mendes, P. Carreira, A. Mateus, and C. Malça
Author(s)
Nowadays, the molds industry searches new markets, with diversified and added value products. The concept associated to the production of thin walled and biodegradable parts mostly manufactured by injection process has assumed a relevant importance due to environmental and economic factors. The growth of a global consciousness about the harmful effects of the conventional polymers in our life quality associated with the legislation imposed, become key factors for the choice of a particular product by the consumer. The target of this work is to provide an integrated solution for the injection of parts with thin walls and manufactured using biodegradable materials. This integrated solution includes the design and manufacture processes of the mold as well as to find the optimum values for the injection parameters in order to become the process effective and competitive. For this, the Moldflow software was used. It was demonstrated that this computational tool provides an effective responsiveness and it can c...
Raimundo Felismina, Miguel Silva, Artur Mateus, and Cândida Malça
Author(s)
It is irrefutable that the use of Unmanned Airborne Vehicle Systems (UAVs) in agricultural tasks and on the analysis of health and vegetative conditions represents a powerful tool in modern agriculture. To contribute to the growth of the agriculture economic sector a seeder to be coupled to any type of UAV was previously developed and designed by the authors. This seeder allows for the deposition of seeds with positional accuracy, i.e., seeds are accurately deposited at pre-established distances between plants [1]. This work aims at analyzing the aerodynamic behavior of UAV/Seeder assembly to determine the suitable inclination - among 0°, 15° and 30° - for its takeoff and for its motion during the seeding operation and, in turn, to define the suitable flight plan that increases the batteries autonomy. For this the ANSYS® FLUENT computational tool was used to simulate a wind tunnel which has as principle the Navier-Stokes differential equations, that designates the fluid flow around the UAV/Seeder assembly...
M Silva, A Mateus, D Oliveira, and C Malça
SAGE Publications
The demand for additive processes that provide components with high technological performance became overriding regardless of the application area. For medical applications, the orthopedics field—multimaterial orthoses and splints—can clearly benefit from direct additive manufacturing using a hybrid process instead of the traditional handmade manufacturing, which is slow, expensive, inaccurate, and difficult to reproduce. The ability to provide faster better orthoses, using innovative services and technologies, resulting in lower recovery times, reduced symptoms, and improved functional capacity, result in a significant impact on quality of life and the well-being of citizens. With these purposes, this work presents an integrate methodology, that includes the tridimensional (3D) scanning, 3D computer-aided design modeling, and the direct digital manufacturing of multimaterial orthoses and splints. Nevertheless, additive manufacturing of components with functional gradients, multimaterial components, e.g. metal/plastic is a great challenge since the processing factors for each one of them are very different. This paper proposes the addition of two advanced additive manufacturing technologies, the selective laser melting and the stereolithography, enabling the production of a photopolymerization of the polymer in the voids of a 3D metal mesh previously produced by selective laser melting. Based on biomimetic structures concept, this mesh is subject to a previous design optimization procedure in order to optimize its geometry, minimizing the mass involved and evidencing increased mechanical strength among other characteristics. A prototype of a hybrid additive manufacturing device was developed and its flexibility of construction, geometrical freedom, and different materials processability is demonstrated through the case study—arm orthosis—presented in this work.
Pedro J. B. F. N. Beirão, , Cândida M. S. P. Malça, and Raimundo P. Felismina
American Institute of Mathematical Sciences (AIMS)
The demand for electricity production has been consistently raising since the last century. In the future, the tendency is to grow even further. Concerning this fact, renewable energy and specifically, wave energy should be considered as an alternative for energy production. However, devices suitable to harness this renewable energy source and convert it into electricity are not yet commercially competitive. This paper is focused on the structural analysis of a wave energy converter (WEC) through the numerical study of several design parameters. Tridimensional computer aided design (3D CAD) numerical models were built and several Finite Element Analyses (FEA) were performed using a commercial finite element code. The main components of the WEC were simulated assuming different materials. The Von Mises stress gradients and displacement fields determined by FEA demonstrated that, regardless of the WEC component, materials with low Young’s modulus seems to be unsuitable for this application. The same is valid for the material yield strength since materials with higher yield strength lead to a better structural behavior of the WEC components. The developed 3D CAD numerical model showed to be suitable to analyze different combinations of structural conditions.
Cyril Santos, Artur Mateus, Ausenda Mendes, and Cândida Malça
Elsevier BV
Abstract Currently, the industry of molds seeks new markets with diversified products and added value. The concept associated with the production by injection of biodegradable pots is therefore of particular significance. Furthermore, environmental factors are increasingly decisive in choosing a product by the consumer, either because of imposed legislation or by the growth of a global awareness of the harmful effects than conventional polymers induce in our quality of life present and future. The general goal of this work was the design, the development and characterization of a thin walled pot for germination of plants made of biodegradable material. In this paper the processing and characterization of the bioplastic selected, the Bioplast GS 2189, is presented. Experimental results confirmed that the biodegradable material undergoes changes during its processing, which is attested by the QIS difference as well as in the reduction of the glass transition temperature, which in the post-processed (injected pot) is lower than the pre-processed material (Bioplast GS 2189). From these results it can be concluded that the injection processing of the Bioplast GS 2189 material affects its properties inducing its degradation process. This behavior can be due to the shear forces and thermal variations to which the material is submitted during the injection process. It was demonstrated that the development of future products in very thin-walled and biodegradable materials obtained by thermoplastic injection process is a competitive and effective solution for molds industries.
F. Brites, C. Malça, F. Gaspar, J.F. Horta, M.C. Franco, S. Biscaia, and A. Mateus
Elsevier BV
Abstract Among natural fillers, cork has been acknowledged as a suitable alternative of other cellular materials that are widely employed in engineering applications due to their low conductivity to heat, noise and vibration, high abrasion resistance and flexibility, high compressibility ratio, among other characteristics [1] . The eco-friendly features of natural fillers based composites make them a very promising and sustainable solution to large markets mainly if additive manufacturing technologies, such as 3D printing, are used [2] . Through 3D printers, engineers, designers and architects can create design and decor products with a free complexity of geometry. In this research work, plastic matrices of HDPE – obtained from conventional suppliers – were reinforced with different ratios of cork waste and natural cork powders – obtained from cork transformation industries – to find the optimum mixture for 3D printing. The effects of cork powders content in the plastic on the morphological, physical and mechanical properties of the composites were investigated through the density, optical microscopy, wettability, thermal analysis and tensile testing. Cork-based composites were processed by an extrusion system, and the mixture of polymer, adhesive and fillers is discussed. The results show that the addition of pure cork and cork waste can be processed with polymers such as HDPE, having adequate physical and mechanical properties.