Sustainable supply chain management: The influence of disposal scenarios on the environmental impact of a 2400 L waste container

This paper analyzes the influence of the supply chain management on the environmental impact of a 2400 L waste disposal container used in most cities of Spain. The studied functional unit, a waste disposal container, made up mostly of plastic materials and a metallic structure, and manufactured in Madrid (Spain), is distributed to several cities at an average distance of 392 km. A life cycle assessment of four different scenarios (SC) has been calculated with the software EcoTool v4.0 (version 4.0; i+: Zaragoza, Spain, 2015) and using Ecoinvent v3.0 database (version 3.0; Swiss Centre for Life Cycle Inventories: St. Gallen, Switzerland, 2013). The environmental impact has been characterized with two different methodologies, recipe and carbon footprint. In order to reduce the environmental impact, several end of life scenarios have been performed, analyzing the influence of the supply chain on a closed-looped system that increases recycling. Closed loop management of the waste and reuse of parts allows companies to stop selling products and start selling the service that their products give to the consumers

Life cycle assessment of a plastic part injected with recycled Polypropylene: a comparison with alternative virgin materials

Plastics recycling is becoming a common action to reduce our products and processes'' environmental impact, and it is of the utmost importance to introduce circular economy strategies. However, for most of the different types of thermoplastics, recycling is not currently its usual end of life due to the technical difficulties in the sorting and recycling processes. This paper presents the complete life cycle assessment of an industrial component made with three different thermoplastics; two virgin thermoplastics typically used for similar parts in the market as Polyamide 6 and Polypropylene, and an alternative source of 100% recycled Polypropylene. All life cycle stages are included in the study. After carrying out the life cycle inventory, calculations of the environmental impact of each life cycle steps have been performed with ReCiPe 2016 EndPoint (H/A) v1.03/World and with IPCC 2013 GWP 100a v1.03 methodologies, comparing all three materials under the same conditions. A sensibility assessment has also been performed, calculating a worst-case scenario of the recycled material, and considering higher material acquisition distances. This study shows that recycled Polypropylene contributes to reducing the overall environmental impact of the component life cycle by 29.8% under ReCiPe, and by 42.8% under Carbon Footprint when compared to virgin Polypropylene. For the worst-case scenario, these reductions in the environmental impact of the component life cycle are also significant: 23.2% and 36.4%, respectively, showing that the use of recycled polymers is a key approach to reduce the environmental impact of plastic components

Yield evaluation of enzyme hydrolysis and dark fermentation of the brown seaweed Rugulopteryx okamurae hydrothermally pretreated by microwave irradiation

Microwave irradiation has been applied to solubilise the organic matter from the invasive seaweed Rugulopterix okamurae as pretreatment for two conventional biological processes: enzyme hydrolysis (EH) for obtaining reducing sugars (RS) and dark fermentation (DF) for obtaining volatile fatty acids (VFAs). As operational conditions for the microwave pretreatment, temperature and time has been tested between 120 and 220 °C and 5–20 min respectively. The maximum solubilisation yield in terms of DOC (26%) through the microwave pretreatment was registered at 220 °C at 20 min. However, the maximum concentration for RS (1.8 g/L) was obtained at 200 °C at 20 min due to the decomposition of monomeric sugars at high temperature and the total polyphenols (TP) were above 0.25 g/L (where inhibition in dark fermentation begins to be noticiable) at 180 °C. When the pretreated biomass was used for the EH the maximum accumulated RS production was 160 mg-RS/g-biomass, at 220 °C which was a 35% better than the RS production for non-pretreated biomass. In the case of the DF tests, the maximum yield of VFAs obtained with the pretreated biomass was 46.3 mg/g-biomass at 220 °C while the maximum hydrogen yield was obtained at 200 °C (6.6 mL-H2/g-biomass) due to the high level of TP (1.1 g/L) of pretreated biomass at 220 °C. Despite of this toxic effect, the VFAs production at 220 °C was 93% higher than in the non-pretreated biomass

Requisitos técnicos de um sistema de informação de determinação de parâmetros de exposição radiológicos : para radiografias do tórax e da coluna lombar

A evolução tecnológica dos sistemas de radiologia digital possibilita a diminuição da exposição dos pacientes à radiação. No entanto, se as potencialidades dos mesmos não forem usadas de forma adequada, podem originar exposições elevadas, desnecessárias nos pacientes. De modo a diminuir o erro humano do Técnico de Radiologia na seleção de parâmetros de exposição e a adequar a exposição radiológica do paciente criou-se um Sistema de Informação (SI) que realiza uma estimativa da dose de radiação, na realização de radiografias da coluna lombar, nas incidências de frente e de perfil, e de radiografias do tórax, na incidência postero-anterior (PA), realizadas seguindo as recomendações. A metodologia adotada para a realização deste trabalho teve como base as quatro primeiras fases do Modelo em Cascata. Inicialmente, foi necessário efetuar uma recolha de informação relativa aos parâmetros de exposição utilizados na realização de radiografias da coluna lombar e do tórax, face à antropometria de cada paciente. Esta recolha possibilitou estimar valores de referência de dose de radiação, que serviram de base para a definição dos requisitos técnicos e desenho do SI a desenvolver. De modo a testar o desenho do sistema foi efetuada uma avaliação do mesmo com base num questionário efetuado a sete Técnicos de Radiologia com cerca de 10 anos de experiência profissional e com Mestrado. Os resultados obtidos nesta avaliação permitem considerar que o desenho do SI cumpre os requisitos pré-definidos, estando reunidas todas as condições necessárias do mesmo para a passagem, num trabalho futuro, às restantes fases do Modelo em Cascata de forma a tornar o SI operacional

O papel do turismo no desenvolvimento de Cabo Verde : turismo e combate à pobreza : Nu djunta-mô

Mestrado em Desenvolvimento e Cooperação InternacionalNo início do século XXI a pobreza é o principal problema do desenvolvimento de Cabo Verde, pois afecta mais de um terço da população. Os números da Organização Mundial do Turismo sugerem que o turismo é importante e está a crescer em muitos países pobres. Assim, as entradas de turistas internacionais evidenciam que o turismo internacional com destino aos países em desenvolvimento (PED) é importante e está em fase de expansão. Ainda que durante a última década do século XX este dinamismo tenha sido significativo em todos os grupos de países, as taxas de crescimento nos PED são consideravelmente maiores do que as registadas nos países desenvolvidos. Em Cabo Verde, na última década do século XX, período de referência da nossa investigação, é um dos sectores que mais cresce e atrai maior investimento directo estrangeiro. O turismo é designado pelo Governo de Cabo Verde, como motor do crescimento e desenvolvimento. Assim, o objecto desde trabalho é o turismo como agente de desenvolvimento em Cabo Verde. Pretendeu-se com este trabalho verificar se o turismo é um instrumento de combate à pobreza em Cabo Verde. Foi com este objectivo em mente que, na primeira parte, se pretendeu estabelecer o quadro teórico de referência e na segunda parte, a contextualização, com base na experiência caboverdiana das questões abordadas na literatura relevante. Este trabalho possibilitou concluir que, o modelo de turismo adoptado actualmente não se constitui como um instrumento de combate à pobreza, visto que encontramos uma ausência de articulação entre o turismo, um dos sectores que mais cresce e atrai maior investimento directo estrangeiro actualmente e as estratégias de combate à pobreza adoptadas, infirmando deste modo a pergunta de partida: "O turismo é um instrumento de combate â pobreza em Cabo Verde?"In the beginning of the 21st century, poverty is still Cape Verde's main development problem, as it affects more than one third of the country's population. The numbers of the Tourism World Organization (WTO) suggest that tourism is an important and growing activity, with the amount of international tourisms expanding in many developing countries. Indeed, although in the last decade of the 20,h century this tourism dynamism is significant in ali groups of countries, the growth rated in developing countries are considerably larger than those registered in developed countries. In Cape Verde, the last decade of the 20lh century, our period of analysis, tourism is one of the sectors that verifies a large growth and attracts the largest share of foreign direct investment. Consequently, the Government of Cape Verde has identified the tourist sector as the country^ motor for growth and economical development. Therefore, this dissertation intends to analyse tourism and its impact, shedding light on its responsibility as the country's development agent. More specifically, with this investigation we intend to verify if tourism can be considered to be an instrumental variable in the fight against poverty in Cape Verde. Keeping this objective in mind, in Part I of this dissertation we attempted to establish the theoretical background, while in Part II, we contextualised the criticai aspects of the literature bymaking use of the Cape Verdean experience. We concluded that the tourism model adopted in Cape Verde couldn't be considered to be instrumental in the fight against poverty, as there is no coordination between this sector and the main poverty strategies implemented in the country.info:eu-repo/semantics/publishedVersio

Efficient partitioning strategies for distributed Web crawling

This paper presents a multi-objective approach to Web space partitioning, aimed to improve distributed crawling efficiency. The in- vestigation is supported by the construction of two different weighted graphs. The first is used to model the topological communication infras- tructure between crawlers and Web servers and the second is used to represent the amount of link connections between servers’ pages. The values of the graph edges represent, respectively, computed RTTs and pages links between nodes. The two graphs are further combined, using a multi-ob jective partitio- ning algorithm, to support Web space partitioning and load allocation for an adaptable number of geographical distributed crawlers. Partitioning strategies were evaluated by varying the number of partiti- ons (crawlers) to obtain merit figures for: i) download time, ii) exchange time and iii) relocation time. Evaluation has showed that our partitio- ning schemes outperform traditional hostname hash based counterparts in all evaluated metric, achieving on average 18% reduction for download time, 78% reduction for exchange time and 46% reduction for relocation time.Fundação para a Ciência e a Tecnologia (FCT

Geographical partition for distributed web crawling

This paper evaluates scalable distributed crawling by means of the geographical partition of the Web. The approach is based on the existence of multiple distributed crawlers each one responsible for the pages belonging to one or more previously identified geographical zones. The work considers a distributed crawler where the assignment of pages to visit is based on page content geographical scope. For the initial assignment of a page to a partition we use a simple heuristic that marks a page within the same scope of the hosting web server geographical location. During download, if the analyze of a page contents recommends a different geographical scope, the page is forwarded to the well-located web server.A sample of the Portuguese Web pages, extracted during the year 2005, was used to evaluate: a) page download communication times and the b) overhead of pages exchange among servers. Evaluation results permit to compare our approach to conventional hash partitioning strategies.Fundação para a Ciência e a Tecnologia (FCT) - POSI/CHS/41739/200

Introducing the discussant role to stimulate debate in the classroom: effects on interactivity, learning outcomes, satisfaction and attitudes

Debates can help students to acquire cross-curricular competencies and improve their learning. However, their use in higher education is scarce and students’ acceptance is low. Considering the effectiveness of discussants in scientific conferences, this research introduces the discussant role as a teaching tool to revitalise debate in the classroom. We propose and test a model to analyse the effects of this activity on three important aspects of learning (interactivity, learning outcomes and satisfaction). We examine how these variables determine students’ attitudes towards the two roles that can be adopted in the activity (discussant or discussed) and their overall evaluation. We test the model regarding students’ expectations and perceptions in the aftermath of the activity. Results show significant relationships between interactivity, learning and satisfaction. Moreover, the three factors strongly determine attitudes and overall evaluation of the activity. Differences before and after experiencing the activity are also found

Metastable phenomena on calcite {1014} surfaces growing from Sr2+–Ca2+–CO3 2- aqueous solutions

In situ atomic force microscopy (AFM) experiments, scanning electron microscopy (SEM) imaging and composition analysis, and X-ray diffraction have provided information about the growth, dissolution and transformation processes promoted by Sr2 + –Ca2 + –CO3 2 aqueous solutions in contact with calcite {101¯4} surfaces. Experiments have shown a wide variety of surface phenomena, such as the influence of the Sr-bearing newly-formed surface on the subsequent growth (template effect), the growth and subsequent dissolution of surfaces and the nucleation of secondary three-dimensional nuclei on calcite surfaces. These phenomena reveal the metastability of the crystallisation system and are a consequence of the interplay between thermodynamics (the relative stability of the two calcite and aragonite structure solid solutions that can be formed), supersaturation of the aqueous solution with respect to the two possible solid solutions, and the crystallographic control of the surfaces on cation incorporation