92 research outputs found
Uncertainty Analysis of the Life-Cycle Greenhouse Gas Emissions and Energy Renewability of Biofuels
Biofuels can contribute substantially to energy security and socio-economic development. However, significant disagreement and controversies exist regarding the actual energy and greenhouse gas (GHG) savings of biofuels displacing fossil fuels. A large number of publications that analyze the life-cycle of biofuel systems present varying and sometimes contradictory conclusions, even for the same biofuel type (Farrell et al., 2006; Malca and Freire, 2004, 2006, 2011; Gnansounou et al., 2009; van der Voet et al., 2010; Borjesson and Tufvesson, 2011). Several aspects have been found to affect the calculation of energy and GHG savings, namely land use change issues and modeling assumptions (Gnansounou et al., 2009; Malca and Freire, 2011). Growing concerns in recent years that the production of biofuels might not respect minimum sustainability requirements led to the publication of Directive 2009/28/EC in the European Union (EPC 2009) and the National Renewable Fuel Standard Program in the USA (EPA 2010), imposing for example the attainment of minimum GHG savings compared to fossil fuels displaced. The calculation of life cycle GHG emission savings is subject to significant uncertainty, but current biofuel life-cycle studies do not usually consider uncertainty. Most often, life-cycle assessment (LCA) practitioners build deterministic models to approximate real systems and thus fail to capture the uncertainty inherent in LCA (Lloyd and Ries, 2007). This type of approach results in outcomes that may be erroneously interpreted, or worse, may promote decisions in the wrong direction (Lloyd and Ries, 2007; Plevin, 2010). It is, therefore, important for sound decision support that uncertainty is taken into account in the life-cycle modeling of biofuels. Under this context, this chapter has two main goals: i) to present a robust framework to incorporate uncertainty in the life-cycle modeling of biofuel systems; and ii) to describe the application of this framework to vegetable oil fuel in Europe. In addition, results are compared with conventional (fossil) fuels to evaluate potential savings achieved through displacement. Following this approach, both the overall uncertainty and the relative importance of the different types of uncertainty can be assessed. Moreover, the relevance of addressing uncertainty issues in biofuels life-cycle studies instead of using average deterministic approaches can be evaluated, namely through identification of important aspects that deserve further study to reduce the overall uncertainty of the system
A Comparative Assessment of Rapeseed Oil and Biodiesel (RME) to Replace Petroleum Diesel Use in Transportation
Study of Metal/Polymer Interface of Parts Produced by a Hybrid Additive Manufacturing Approach
Acknowledgments
This research work was supported by the Portuguese Foundation for Science and Technology (FCT) and Centro2020 through the Project reference: UID/Multi/04044/2013, PAMI - ROTEIRO/0328/2013 (NÂș 022158) and Portuguese National Innovation Agency (ANI) through the Project reference POCI-01-0247-FEDER-017963, NEXT.parts â Next Generation of Advanced Hybrid Parts (co-promotion nÂș 17963).The additive manufacturing of multimaterial parts, e.g. metal/plastic, with functional
gradients represents for current market demands a great potential of applications [1]. Metal Polymer parts combine the good mechanical properties of the metals with the low weight characteristics, good impact strength, good vibration and sound absorption of the polymers. Nevertheless, the coupling between metal and polymers is a great challenge since the processing factors for each one of them are very different. In addition, a system that makes the hybrid processing - metal/polymer - using
only one operation is unknown [2, 3]. To overcome this drawback, a hybrid additive manufacturing system based on the additive technologies of SLM and SL was recently developed by the authors. The SLM and SL techniques joined enabling the production of a photopolymerization of the polymer in the voids of a 3D metal mesh previously produced by SLM [4]. The purpose of this work is the study on the metal/polymer interface of hybrid parts manufactured from the hybrid additive manufacturing system [5]. For this, a core of tool steel (H13) and two different types of photopolymers:
one elastomeric (BR3D-DL-Flex) and another one rigid (BR3D-DL-Hard) are considered. A set of six samples for each one of metal core/polymer combination was manufactured and submitted to tensile tests.info:eu-repo/semantics/publishedVersio
The Use of Polypropylene and High-Density Polyethylene on Cork Plastic Composites for Large Scale 3D Printing
Acknowledgements This work is supported by the Fundação para a CiĂȘncia e a Tecnologia (FCT) and Centro2020 through the Project references: UID/Multi/04044/2013 and PAMI - ROTEIRO/0328/2013 (NÂș 022158). In addition, the authors acknowledge the funding from the project World of Outstanding Wool and Wood (WOWW), POCI-01-0247-FEDER-017574 from the Portuguese National Innovation Agency. The authors gratefully acknowledge to Amorim Cork Composites for the cork powder. We thank Ana O. Tojeira and Ana R. Fonseca for the support provided in performing the laboratorial tests as Laboratory Managing Engineers.This work focuses on studying the possibility of 3D printing of composite materials
composed by cork and a polymer matrix (CPC). Initially the cork was mixed with two types of polymers (HDPE and PP) in different proportions and later processed using extrusion and injection. The composites were tested to study the physical, chemical and mechanical properties. The material was then tested on a large-scale 3D printer to study its feasibility and the ability to produce new products through 3D printing. Attention was focused on the use of pure cork, varying the concentration of cork and coupling agent in thermoplastic matrix composites of PP and HDPE. It was demonstrated that the increase of 5wt.% of coupling agent in the two types of polymers
significantly improved the mechanical properties and adhesion between the phases but the increase
in cork concentration decreased mechanical properties and crystallinity. The CPCs with PP showed
to have better mechanical properties, better aesthetic and internal structural quality, and easier
processability than those with HDPE matrix. Nevertheless, the HDPE CPCs showed a high degree
of crystallization.
Concerning 3D printing, it was demonstrated the possibility of making new products based on
natural cork fibers, showing promising results, although additional research is still needed to
optimize the process.info:eu-repo/semantics/publishedVersio
A Brief Review on Processes for Cartilage Repair
The aim of the present review was to highlight some of the available processes for cartilage repair and regeneration. Considering the high impact that cartilage degeneration has in the quality of life, in an aging society, efforts to promote better treatments are crucial. The current available processes have advantages and drawbacks, that should be further investigated, aiming to obtain tailored and successful repair. Finally, some suggestions for tissue engineering strategies are presented, so that the scientific community can debate pros and cons to be investigated.info:eu-repo/semantics/publishedVersio
Life-cycle assessment of microalgae biodiesel: a review
Microalgae are an attractive way to produce biofuels due to the ability to accumulate lipids and very high photosynthetic yields. This article presents a review of life-cycle assessment studies of microalgae biodiesel production, including an analysis of modeling choices and assumptions. A high variation in GHG emissions (between -0.75 and 2.9 kg CO2eq MJ-1) was found and the main causes were investigated, namely modeling choices (e.g. the approach used to deal with multifunctionality), and a high parameter uncertainty in microalgae cultivation, harvesting and oil extraction processes
Physical rehabilitation programs for bedridden patients with prolonged immobility: a scoping review
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 Instituteâs (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.This research was co-financed by the European Regional Development Fund (ERDF)
through the partnership agreement Portugal 2020âOperational Programme for Competitiveness
and Internationalization (COMPETE2020) under the project POCI-01-0247-FEDER-047087 ABLEFIT:
Desenvolvimento de um Sistema avançado para Reabilitação
An interregional, transdisciplinary and good practice-based approach for frailty: the mind&gait project
Social facilities such residential
structures and day-centres increasingly seek
integrated, structured, adapted, creative, dynamic and
economic strategies to prevent frailty. The arising
need of an aged and frail population requires
innovative interventions and products to prevent
cognitive and physical decline. The interregional
MIND&GAIT project aims to promote independent
living in frail older adults by improving cognition and
gait ability by using assistive products. This
transdisciplinary strategy within a 24-months period
expects as projectâ deliverables: i) a structured and
good practice-based combined intervention (CI)
consisting of a cognitive stimulation programme and
a physical exercise programme; ii) an auto-blocking
mechanism for rolling walkers with biofeedback
acquisition (ABMRW); iii) a randomized clinical trial
to assess CIâ effectiveness; and iv) a web-platform to
be used as a repository that will support and
disseminate the intervention materials, covering the
action-line of translational research. Positive benefits
are expected in prevention and maintenance of frail
older adultsâ capacities. Preliminary results showed
positive effects on the improvement of cognitive and
physical functions, functionality and depressive
symptomatology. The interregional geographical
coverage induced by MIND&GAIT underlines the
potential replicability of the project extension to the
community in the Centro and Alentejo regions of
Portugal. MIND&GAIT network supports actions and
provides learning opportunities and emergence of
locally-embedded support systems towards social
innovation for older adults
- âŠ