Innovation through virtual communities of practice: motivations and constraints in the knowledge-creation process

This paper appears in International Journal of Projectics. Vol 4(1), pp. 39-49

Innovative manufacturing process for hybrid pultruded products based on cork and polymeric pre-shapes

Pultruded products are being targeted by a growing demand due to its excellent mechanical properties and low chemical reactivity, ensuring a low level of maintenance operations and allowing an easier assembly operation process than equivalent steel bars. In order to improve the mechanical drawing process and solve some acoustic and thermal insulation problems, pultruded pipes of glass fibre reinforced plastics (GFRF) can be filled with special products that increase their performance regarding the issues previously referred. The great challenge of this work was drawing a new equipment able to produce pultruded pipes filled with cork or polymeric pre-shaped bars as a continuous process. The project was carried out successfully and the new equipment was built and integrated in the pultrusion equipment already existing, allowing to obtain news products with higher added-value in the market, covering some needs previously identified in the field of civil construction.

Design of experiments applied to the mix design process of polymer mortar materials modified with GFRP recyclates

In this work, the effect of incorporation of recycled glass fibre reinforced plastics (GFRP) waste materials, obtained by means of shredding and milling processes, on mechanical behavior of polyester polymer mortar (PM) materials was assessed. For this purpose, different contents of GFRP recyclates (between 4% up to 12% in mass), were incorporated into polyester PM materials as sand aggregates and filler replacements. The effect of silane coupling agent addition to resin binder was also evaluated. Applied waste material was proceeding from the shredding of the leftovers resultant from the cutting and assembly processes of GFRP pultrusion profiles. Currently, these leftovers, jointly with unfinished products and scrap resulting from pultrusion manufacturing process, are landfilled, with supplementary added costs. Thus, besides the evident environmental benefits, a viable and feasible solution for these wastes would also conduct to significant economic advantages. Design of experiments and data treatment were accomplish by means of full factorial design approach and analysis of variance ANOVA. Experimental results were promising toward the recyclability of GFRP waste materials as aggregates and reinforcement for PM materials, with significant improvements on mechanical properties with regard to non-modified formulations.

Optimization of the Pultrusion process

Manufacturing processes need permanently to innovate and optimize because any can be susceptible to continuous improvement. Innovation and commitment to the development of these new solutions resulting from existing expertise and the continuing need to increase productivity, flexibility and ensuring the necessary quality of the manufactured products. To increase flexibility, it is necessary to significantly reduce set-up times and lead time in order to ensure the delivery of products ever faster. This objective can be achieved through a normalization of the pultrusion line elements. Implicitly, there is an increase of productivity by this way. This work is intended to optimize the pultrusion process of structural profiles. We consider all elements of the system from the storehouse of the fibers (rack) to the pultrusion die. Particular attention was devoted to (a) the guidance system of the fibers and webs, (b) the resin container where the fibers are impregnated, (c) standard plates positioning of the fibers towards the entrance to the spinneret and also (d) reviewed the whole process of assembling and fixing the die as well as its the heating system. With the implementation of these new systems was achieved a significant saving of time set-up and were clearly reduced the unit costs of production. Quality assurance was also increased.

Soil sampling design and sampling techniques for soil properties monitoring – common difficulties related to forest soils

Mathematical models and statistical analysis are key instruments in soil science scientific research as they can describe and/or predict the current state of a soil system. These tools allow us to explore the behavior of soil related processes and properties as well as to generate new hypotheses for future experimentation. A good model and analysis of soil properties variations, that permit us to extract suitable conclusions and estimating spatially correlated variables at unsampled locations, is clearly dependent on the amount and quality of data and of the robustness techniques and estimators. On the other hand, the quality of data is obviously dependent from a competent data collection procedure and from a capable laboratory analytical work. Following the standard soil sampling protocols available, soil samples should be collected according to key points such as a convenient spatial scale, landscape homogeneity (or non-homogeneity), land color, soil texture, land slope, land solar exposition. Obtaining good quality data from forest soils is predictably expensive as it is labor intensive and demands many manpower and equipment both in field work and in laboratory analysis. Also, the sampling collection scheme that should be used on a data collection procedure in forest field is not simple to design as the sampling strategies chosen are strongly dependent on soil taxonomy. In fact, a sampling grid will not be able to be followed if rocks at the predicted collecting depth are found, or no soil at all is found, or large trees bar the soil collection. Considering this, a proficient design of a soil data sampling campaign in forest field is not always a simple process and sometimes represents a truly huge challenge. In this work, we present some difficulties that have occurred during two experiments on forest soil that were conducted in order to study the spatial variation of some soil physical-chemical properties. Two different sampling protocols were considered for monitoring two types of forest soils located in NW Portugal: umbric regosol and lithosol. Two different equipments for sampling collection were also used: a manual auger and a shovel. Both scenarios were analyzed and the results achieved have allowed us to consider that monitoring forest soil in order to do some mathematical and statistical investigations needs a sampling procedure to data collection compatible to established protocols but a pre-defined grid assumption often fail when the variability of the soil property is not uniform in space. In this case, sampling grid should be conveniently adapted from one part of the landscape to another and this fact should be taken into consideration of a mathematical procedure.

Optimizing the embedded heaters position in the pultrusion process using finite element analysis

This study is based on a previous experimental work in which embedded cylindrical heaters were applied to a pultrusion machine die, and resultant energetic performance compared with that achieved with the former heating system based on planar resistances. The previous work allowed to conclude that the use of embedded resistances enhances significantly the energetic performance of pultrusion process, leading to 57% decrease of energy consumption. However, the aforementioned study was developed with basis on an existing pultrusion die, which only allowed a single relative position for the heaters. In the present work, new relative positions for the heaters were investigated in order to optimize heat distribution process and energy consumption. Finite Elements Analysis was applied as an efficient tool to identify the best relative position of the heaters into the die, taking into account the usual parameters involved in the process and the control system already tested in the previous study. The analysis was firstly developed with basis on eight cylindrical heaters located in four different location plans. In a second phase, in order to refine the results, a new approach was adopted using sixteen heaters with the same total power. Final results allow to conclude that the correct positioning of the heaters can contribute to about 10% of energy consumption reduction, decreasing the production costs and leading to a better eco-efficiency of pultrusion process.

Numerical Method to Predict Void Formation during The Liquid Composite Molding Process

Void formation during the injection phase of the liquid composite molding process can be explained as a consequence of the non-uniformity of the flow front progression. This is due to the dual porosity within the fiber perform (spacing between the fiber tows is much larger than between the fibers within in a tow) and therefore the best explanation can be provided by a mesolevel analysis, where the characteristic dimension is given by the fiber tow diameter of the order of millimeters. In mesolevel analysis, liquid impregnation along two different scales; inside fiber tows and within the open spaces between the fiber tows must be considered and the coupling between the flow regimes must be addressed. In such cases, it is extremely important to account correctly for the surface tension effects, which can be modeled as capillary pressure applied at the flow front. Numerical implementation of such boundary conditions leads to illposing of the problem, in terms of the weak classical as well as stabilized formulation. As a consequence, there is an error in mass conservation accumulated especially along the free flow front. A numerical procedure was formulated and is implemented in an existing Free Boundary Program to reduce this error significantly.

Performance of concrete made with aggregates recycled from precasting industry waste: influence of the crushing process

The aim of this paper is to evaluate the influence of the crushing process used to obtain recycled concrete aggregates on the performance of concrete made with those aggregates. Two crushing methods were considered: primary crushing, using a jaw crusher, and primary plus secondary crushing (PSC), using a jaw crusher followed by a hammer mill. Besides natural aggregates (NA), these two processes were also used to crush three types of concrete made in laboratory (L20, L45 e L65) and three more others from the precast industry (P20, P45 e P65). The coarse natural aggregates were totally replaced by coarse recycled concrete aggregates. The recycled aggregates concrete mixes were compared with reference concrete mixes made using only NA, and the following properties related to the mechanical and durability performance were tested: compressive strength; splitting tensile strength; modulus of elasticity; carbonation resistance; chloride penetration resistance; water absorption by capillarity; water absorption by immersion; and shrinkage. The results show that the PSC process leads to better performances, especially in the durability properties.

Semi-destructive in situ tests as support to the assessment of a conservation process

This paper refers to the assessment on site by semi-destructive testing (SDT) methods of the consolidation efficiency of a conservation process developed by Henriques (2011) for structural and non-structural pine wood elements in service. This study was applied on scots pine wood (Pinus sylvestris L.) degraded by fungi after treatment with a biocidal product followed by consolidation with a polymeric product. This solution avoids substitutions of wood moderately degraded by fungi, improving its physical and mechanical characteristics. The consolidation efficiency was assessed on site by methods of drill resistance and penetration resistance. The SDT methods used showed good sensitivity to the conservation process and could evaluate their effectiveness. (C) 2015 Elsevier Ltd. All rights reserved.

The impact of driving styles on fuel consumption: a data-warehouse-and-data-mining-based discovery process

This paper discusses the results of applied research on the eco-driving domain based on a huge data set produced from a fleet of Lisbon's public transportation buses for a three-year period. This data set is based on events automatically extracted from the control area network bus and enriched with GPS coordinates, weather conditions, and road information. We apply online analytical processing (OLAP) and knowledge discovery (KD) techniques to deal with the high volume of this data set and to determine the major factors that influence the average fuel consumption, and then classify the drivers involved according to their driving efficiency. Consequently, we identify the most appropriate driving practices and styles. Our findings show that introducing simple practices, such as optimal clutch, engine rotation, and engine running in idle, can reduce fuel consumption on average from 3 to 5l/100 km, meaning a saving of 30 l per bus on one day. These findings have been strongly considered in the drivers' training sessions.

Use of quantitative structure-property relationships to study the solvation process of 18-crown-6

Solution enthalpies of 18-crown-6 have been obtained for a set of 14 protic and aprotic solvents at 298.15 K. The complementary use of Solomonov's methodology and a QSPR-based approach allowed the identification of the most significant solvent descriptors that model the interaction enthalpy contribution of the solution process (Delta H-int(A/S)). Results were compared with data previously obtained for 1,4-dioxane. Although the interaction enthalpies of 18-crown-6 correlate well with those of 1,4-dioxane, the magnitude of the most relevant parameters, pi* and beta, is almost three times higher for 18-crown-6. This is rationalized in terms of the impact of the solute's volume in the solution processes of both compounds. (C) 2015 Elsevier B.V. All rights reserved.

Optimization of antioxidants extraction from coffee silverskin, aroasting by-product, having in view a sustainable process

Coffee silverskin is a major roasting by-product that could be valued as a source of antioxidant compounds. The effect of the major variables (solvent polarity, temperature and extraction time) affecting the extraction yields of bioactive compounds and antioxidant activity of silverskin extracts was evaluated. The extracts composition varied significantly with the extraction conditions used. A factorial experimental design showed that the use of a hydroalcoholic solvent (50%:50%) at 40 °C for 60 min is a sustainable option to maximize the extraction yield of bioactive compounds and the antioxidant capacity of extracts. Using this set of conditions it was possible to obtain extracts containing total phenolics (302.5 ± 7.1 mg GAE/L), tannins (0.43 ± 0.06 mg TAE/L), and flavonoids (83.0 ± 1.4 mg ECE/L), exhibiting DPPHradical dot scavenging activity (326.0 ± 5.7 mg TE/L) and ferric reducing antioxidant power (1791.9 ± 126.3 mg SFE/L). These conditions allowed, in comparison with other “more effective” for some individual parameters, a cost reduction, saving time and energy.

Saúde mental, qualidade de vida e acesso aos cuidados de saúde na comunidade brasileira de Lisboa

Introdução: A utilização de serviços de saúde tem implicações importantes para o estado de saúde das populações. As políticas de imigração adoptadas nos países de destino têm influência no estado de saúde das comunidades imigrantes. Políticas que limitam o acesso de imigrantes aos cuidados de saúde aumentarão a vulnerabilidade e os riscos na saúde. Apesar da imigração promover uma série de rupturas na vida do sujeito, migrar, por si só, não pode ser considerado como factor de risco no âmbito da saúde e da saúde mental. O peso dos determinantes socioeconómicos tem ganho relevância no estudo das migrações, estado de saúde geral e mental. Isto porque, em geral, os imigrantes estão em situação mais precária do que a população autóctone. O estatuto socioeconómico baixo, as condições precárias de habitação e de trabalho, a falta de suporte social e a irregularidade jurídica são indicadores de risco acrescido para a saúde mental. Neste sentido é um desafio de monta os governos estabelecerem medidas sustentadas e, simultaneamente, integradoras dos imigrantes. Em Portugal, considera-se que há escassez de estudos relacionados com a área das migrações e da saúde.Metodologia: Estudo exploratório, descritivo e transversal. A finalidade foi a de identificar o estado de saúde, saúde mental e qualidade de vida da comunidade brasileira residente em Lisboa e o seu acesso aos serviços de saúde. Este estudo teve como principais objectivos a caracterização sociodemográfica, a identificação de variáveis inerentes ao processo migratório, a identificação da auto-apreciação do estado de saúde, a caracterização do acesso aos cuidados de saúde, a identificação do grupo em provável sofrimento psicológico, a comparação entre os resultados dos imigrantes juridicamente regulares e irregulares e a comparação entre a população imigrante e a população portuguesa. Inicialmente, foi prevista a utilização da técnica de amostragem de propagação geométrica ou snowball, pois a amostra tornar-se-ia maior à medida que os próprios inquiridos identificam outros potenciais respondentes. Ao longo do estudo, a metodologia inicial mostrou-se insuficiente para estabelecer uma amostra mais representativa dos imigrantes juridicamente irregulares. Para este feito, foi utilizada a metodologia de amostragem por conveniência e o local escolhido para a recolha da amostra foi o Consulado do Brasil em Lisboa. O instrumento de recolha de dados empregue baseou-se no questionário utilizado no 4º Inquérito Nacional de Saúde. O MHI-5 (Mental Health Index 5) é um instrumento de saúde mental e é parte integrante do inquérito, sendo recomendado pela Organização Mundial de Saúde. Consta de cinco itens relativos à saúde mental e os resultados são classificados através de um indicador que mede a existência de provável sofrimento psicológico. Foram incluídos no estudo 213 brasileiros. De seguida, procedeu-se ao tratamento estatístico dos dados. Resultados: A população inquirida é jovem, a maior parte tem entre 18 e 44 anos. As mulheres representam mais de metade da amostra. A taxa de actividade é elevada e a taxa de desemprego é similar à nacional. A inserção laboral prioritária é nos segmentos pouco qualificados ou de semi-qualificação. Aproximadamente um terço dos inquiridos afirmou ser beneficiário do Sistema Nacional de Saúde. A autoapreciação do estado de saúde é classificada como bastante positiva, assim como a qualidade de vida. O provável sofrimento psicológico, definido no MHI-5 pelo ponto de corte no score 52, atinge 23,3% dos participantes. Os homens apresentam melhores resultados do que as mulheres. Além disso, para os valores mais baixos no MHI-5 foram encontradas relações com as longas jornadas de trabalho e o diagnóstico de doença crónica.Discussão: O presente estudo apresenta limitações em relação à dimensão da amostra e à provável existência de enviesamento pela ausência de aleatorização. Apesar da legislação portuguesa garantir o acesso aos serviços de saúde e garantir a equidade no caso dos imigrantes que fazem descontos para a Segurança Social, apenas um terço referiu ser beneficiário do Sistema Nacional de Saúde. Este dado pode ser justificado por factores como o cumprimento da lei por alguns serviços e, também, pela falta de conhecimento da legislação e da forma de funcionamento do Serviço Nacional de Saúde por parte dos imigrantes. O facto das mulheres representarem o maior grupo em provável sofrimento psicológico é consistente com a literatura. As hipóteses levantadas para explicar este resultado podem ser agrupadas em: artefactos metodológicos, causalidade biológica e determinação social. Em relação ao instrumento, é possível que o MHI-5 se comporte de forma diferente no que diz respeito ao género.-------------------------------------------Introduction: The utilization of health services has important implications for the health state of the populations. The immigration policies adopted in the destiny countries are going to influence the health state of immigrant communities. Policies that limit the access of immigrants to health care are going to increase the vulnerability and the risk factor in health. Although immigration promotes several disruptive actions in ones life, migrating, on its own, cannot be considered as a risk factor for health and mental health. The preponderance of the socioeconomic factors has gained relevance in the study of migrations and also in the study of general health state and mental health. This happens because, in general, immigrants are in a more unfavorable situation compared with the destiny country population. The low socioeconomic status, the poor working and housing conditions, the lack of social support and the juridical irregularity are indicators of the incremented risk to mental health. Therefore, it is a major challenge for governments to find sustainable, and simultaneously, integrative measures for the immigrants. The studies related with the migrations and health in Portugal were considered to be few.Methods: It is an exploratory, descriptive and transversal study. The purpose is to identify the health state, mental health, quality of life and the access to health care of the Brazilian community resident in Lisbon. In addition, this study has as main goals the sociodemographic characterization, the variables identification inherent to the migrating process, the identification of the self-appreciation of health state, the characterization of the access to health care, the identification of the group in probable psychological suffer, the comparison between the results of regular and irregular immigrants and the comparison between the immigrant population and the Portuguese population. Initially it was predicted the utilization of the geometric propagation or “snowball”, as sampling technique, because the sample becomes larger as one answerer identify other potential answering persons. Along with the study, the methodology has shown insufficient to establish a more representative sample of the irregular immigrants. For this latter case, it was used a convenient sample methodology and the place chosen for the sample gathering was the “Consulate of Brazil in Lisbon”. The instrument was based in the questionnaire used in the “4th National Health Inquiry”. The MHI-5 (Mental Health Index 5) is a mental health instrument which is part of the enquiry and it is recommended by the World Health Organization. There are five items related to mental health and the results are classified through an indicator which measures the existence of a probable psychological suffer. It were included 213 Brazilian in the study. After, the statistical treatment of the data took place.Results: The answering population is young and the majority is between the 18 and 44 years of age. The women represent more than one half of the sample. The activity rate is high and the unemployment rate is similar to the national one. The priority labor insertion is in the few qualified or of semi-qualification segments. Approximately, one third of the answering people has stated to be beneficiary of the National Health System. The self-appreciation of the health state as well as the quality of life are classified as fairly positive ones. The probable psychological suffer, as defined in the MHI-5 through the cut point in the score below or equal to 52, reaches 23,3% of the sample population. Men show the better results than women. Further, for the lower values of MHI-5 it was found a relation with the long work periods and chronic disease diagnostic. Discussion: The present study evidences limitations in relation to the sample dimension and in relation to the existence of biases due to the lack of randomness. Although the Portuguese legislation guarantees the access to health services and the equality in the cases of the immigrants that do their Social Security discounts, only one third has mentioned to be beneficiary of the National Health System. This can be justified by several facts such as the non-fulfillment of law by some national services or the lack of knowledge of the legislation or the functioning process of the National Health System. Women representing the bigger group in probable psychological suffer has been coherent with the literature review. The hypothesis set to explain this result might be grouped in: methodological artifacts, biologic cause and social determination. In relation to the instrument used, it may be that MHI-5 behaves in a different way in respect to gender.

Analysis of diffusion process in fractured reservoirs using fractional derivative approach

The fractal geometry is used to model of a naturally fractured reservoir and the concept of fractional derivative is applied to the diffusion equation to incorporate the history of fluid flow in naturally fractured reservoirs. The resulting fractally fractional diffusion (FFD) equation is solved analytically in the Laplace space for three outer boundary conditions. The analytical solutions are used to analyze the response of a naturally fractured reservoir considering the anomalous behavior of oil production. Several synthetic examples are provided to illustrate the methodology proposed in this work and to explain the diffusion process in fractally fractured systems.

A estruturação dos determinantes relevantes no processo de decisão do investimento direto estrangeiro em Portugal e em Espanha

Dissertação de Mestrado apresentada ao Instituto de Contabilidade e Administração do Porto para a obtenção do grau de Mestre em Contabilidade e Finanças, sob orientação do Dr. Luís Pereira Gomes