8,562 research outputs found

    Designing carbon fibre-reinforced composites with improved structural retention on exposure to heat/fire

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    Carbon fibre-reinforced composites (CFRCs) are increasing in popularity due to their high strength-to-weight ratio and resistance to corrosion. However, when exposed to temperatures above 300¬įC, the polymer matrix within CFRCs decomposes and then starts burning, exposing carbon fibres to the surroundings. The residual carbon fibres being electrically conductive, may pose a hazard to the surrounding electronics. Moreover, at over 550¬įC the carbon fibres begin to oxidise. This can lead to fibre defibrillation which also poses significant harm to human health as broken fibres can be sharp enough to cut through human skin, and under 7¬Ķm these particles are considered respirable where on inhalation they can causes damage to the trachea and lungs. While considerable work has been carried out on assessing the effect of heat/fire on degradation of the composite resin (matrix) and CFRCs themselves, there are limited studies on identifying the damage to carbon fibres within CFRCs and the hazards posed by the exposed damaged carbon fibres. This study examined the damage caused by high temperatures, radiant heat and flames on carbon fibres and CFRCs, and the effects on their physical properties. A methodology was developed to study and quantify the structural damage to carbon fibres and CFRCs after exposure to a range of heat/fire conditions. These included thermogravimetric analysis (up to 900oC in nitrogen and air atmospheres), the tube furnace (450oC‚Äď900oC), cone calorimeter (35kWm-2 to 75kWm-2 ) and a propane burner (116kWm-2 ) to simulate jet fuel fire conditions. Residual fibres were removed from different parts of the CFRCs and the physical properties were studied, such as fibre diameter reduction, change in electrical conductivity and decrease in tensile strength. It was found that at heat fluxes ‚Č•60kWm-2 oxidation of the carbon fibres occurred. After 10min exposure to the propane flame, fibres in direct contact with the flame showed signs of internal oxidation.The aim of this PhD project was to also improve the structural retention of CFRCs on exposure to heat/fire so that the structural integrity is maintained and the carbon fibres are not exposed to the environment. To address this, the following approaches were undertaken: ‚ÄĘ Modification of the resin by adding flame retardants and nanoparticles in order to reduce the flammability of CFRCs, improve the mechanical integrity of the char and its adherence to the fibre. Flame retardants included ammonium polyphosphate, resorcinol bis-(diphenyl phosphate), 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide, and the nano-additives, nano-clay, layered double hydroxide and carbon nano-tubes. Cone calorimeter testing at 75kWm-2 showed that the addition of 15wt% ammonium polyphosphate resulted in large char formation and adherence to fibres in the underlying plies, which resulted in less oxidation to these carbon fibres. The addition of layered double hydroxides and carbon nano-tubes on the other hand caused pitting on fibres. ‚ÄĘ Provide heat protection to carbon fibres within CFRCs by the inclusion of high performance fibrous veils/woven fabrics of aramid, basalt, E-glass, polyphenylene sulphide and Kevlar. The inclusion of the woven E-glass resulted in a notable reduction in the percentage of carbon fibre oxidised. However, the volatiles produced during the decomposition of Kevlar and PPS sensitised the carbon fibre to oxidation, causing it to occur more rapidly and at a lower temperature. ‚ÄĘ Using high temperature chemical coatings to individually coat carbon fibres prior to making the CFRCs. Ceramic compounds (silica, alumina and zirconia), chosen as coating materials because of their high thermal stability, were applied by different processes. The most promising coatings included alumina and silica formed via sol-gel process and polysiloxane deposited during plasma exposure. Tows coated in these chemicals underwent heat testing in a tube furnace where those coated with alumina maintained the largest fibre diameters. While polysiloxane coating provided oxidation protection up to 600¬įC, after which cracks in the coating were observed. This was attributed to the mechanical mismatch of the polysiloxane coating and the carbon fibre

    KYT2022 Finnish Research Programme on Nuclear Waste Management 2019‚Äď2022 : Final Report

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    KYT2022 (Finnish Research Programme on Nuclear Waste Management 2019‚Äď2022), organised by the Ministry of Economic Affairs and Employment, was a national research programme with the objective to ensure that the authorities have sufficient levels of nuclear expertise and preparedness that are needed for safety of nuclear waste management. The starting point for public research programs on nuclear safety is that they create the conditions for maintaining the knowledge required for the continued safe and economic use of nuclear energy, developing new know-how and participating in international collaboration. The content of the KYT2022 research programme was composed of nationally important research topics, which are the safety, feasibility and acceptability of nuclear waste management. KYT2022 research programme also functioned as a discussion and information-sharing forum for the authorities, those responsible for nuclear waste management and the research organizations, which helped to make use of the limited research resources. The programme aimed to develop national research infrastructure, ensure the continuing availability of expertise, produce high-level scientific research and increase general knowledge of nuclear waste management

    Anu√°rio cient√≠fico da Escola Superior de Tecnologia da Sa√ļde de Lisboa - 2021

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    √Č com grande prazer que apresentamos a mais recente edi√ß√£o (a 11.¬™) do Anu√°rio Cient√≠fico da Escola Superior de Tecnologia da Sa√ļde de Lisboa. Como institui√ß√£o de ensino superior, temos o compromisso de promover e incentivar a pesquisa cient√≠fica em todas as √°reas do conhecimento que contemplam a nossa miss√£o. Esta publica√ß√£o tem como objetivo divulgar toda a produ√ß√£o cient√≠fica desenvolvida pelos Professores, Investigadores, Estudantes e Pessoal n√£o Docente da ESTeSL durante 2021. Este Anu√°rio √©, assim, o reflexo do trabalho √°rduo e dedicado da nossa comunidade, que se empenhou na produ√ß√£o de conte√ļdo cient√≠fico de elevada qualidade e partilhada com a Sociedade na forma de livros, cap√≠tulos de livros, artigos publicados em revistas nacionais e internacionais, resumos de comunica√ß√Ķes orais e p√≥steres, bem como resultado dos trabalhos de 1¬ļ e 2¬ļ ciclo. Com isto, o conte√ļdo desta publica√ß√£o abrange uma ampla variedade de t√≥picos, desde temas mais fundamentais at√© estudos de aplica√ß√£o pr√°tica em contextos espec√≠ficos de Sa√ļde, refletindo desta forma a pluralidade e diversidade de √°reas que definem, e tornam √ļnica, a ESTeSL. Acreditamos que a investiga√ß√£o e pesquisa cient√≠fica √© um eixo fundamental para o desenvolvimento da sociedade e √© por isso que incentivamos os nossos estudantes a envolverem-se em atividades de pesquisa e pr√°tica baseada na evid√™ncia desde o in√≠cio dos seus estudos na ESTeSL. Esta publica√ß√£o √© um exemplo do sucesso desses esfor√ßos, sendo a maior de sempre, o que faz com que estejamos muito orgulhosos em partilhar os resultados e descobertas dos nossos investigadores com a comunidade cient√≠fica e o p√ļblico em geral. Esperamos que este Anu√°rio inspire e motive outros estudantes, profissionais de sa√ļde, professores e outros colaboradores a continuarem a explorar novas ideias e contribuir para o avan√ßo da ci√™ncia e da tecnologia no corpo de conhecimento pr√≥prio das √°reas que comp√Ķe a ESTeSL. Agradecemos a todos os envolvidos na produ√ß√£o deste anu√°rio e desejamos uma leitura inspiradora e agrad√°vel.info:eu-repo/semantics/publishedVersio

    Iron Oxide Nanoparticles and Nano-Composites: An Efficient Tool for Cancer Theranostics

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    In recent years, functional Iron oxides nanoparticles and nano-composites have gained a special traction in the field of nano-biomedicine, owing to their multifunctional capabilities that includes the inherent magnetic resonance imaging, magnetic bioseparation, cargo delivery and magnetic hyperthermia behavior. Interestingly, there are various forms of iron oxides available, with each form having their own specific characteristics. The different polymorphic forms of iron oxides are obtained through various synthetic routes and are usually surface modified to prevent their oxidation. The chapter shall encompass the synthesis and surface modification of Iron oxides nanoparticles, physicochemical properties, and theranostic application of the magnetic iron oxide nanoparticles in cancer. Also, the future directions of Iron oxide nanoparticles and nano-composites towards the achievement of clinically realizable nanoformulation for cancer theranostic applications were highlighted

    Gasificação direta de biomassa para produção de gás combustível

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    The excessive consumption of fossil fuels to satisfy the world necessities of energy and commodities led to the emission of large amounts of greenhouse gases in the last decades, contributing significantly to the greatest environmental threat of the 21st century: Climate Change. The answer to this man-made disaster is not simple and can only be made if distinct stakeholders and governments are brought to cooperate and work together. This is mandatory if we want to change our economy to one more sustainable and based in renewable materials, and whose energy is provided by the eternal nature energies (e.g., wind, solar). In this regard, biomass can have a main role as an adjustable and renewable feedstock that allows the replacement of fossil fuels in various applications, and the conversion by gasification allows the necessary flexibility for that purpose. In fact, fossil fuels are just biomass that underwent extreme pressures and heat for millions of years. Furthermore, biomass is a resource that, if not used or managed, increases wildfire risks. Consequently, we also have the obligation of valorizing and using this resource. In this work, it was obtained new scientific knowledge to support the development of direct (air) gasification of biomass in bubbling fluidized bed reactors to obtain a fuel gas with suitable properties to replace natural gas in industrial gas burners. This is the first step for the integration and development of gasification-based biorefineries, which will produce a diverse number of value-added products from biomass and compete with current petrochemical refineries in the future. In this regard, solutions for the improvement of the raw producer gas quality and process efficiency parameters were defined and analyzed. First, addition of superheated steam as primary measure allowed the increase of H2 concentration and H2/CO molar ratio in the producer gas without compromising the stability of the process. However, the measure mainly showed potential for the direct (air) gasification of high-density biomass (e.g., pellets), due to the necessity of having char accumulation in the reactor bottom bed for char-steam reforming reactions. Secondly, addition of refused derived fuel to the biomass feedstock led to enhanced gasification products, revealing itself as a highly promising strategy in terms of economic viability and environmental benefits of future gasification-based biorefineries, due to the high availability and low costs of wastes. Nevertheless, integrated techno economic and life cycle analyses must be performed to fully characterize the process. Thirdly, application of low-cost catalyst as primary measure revealed potential by allowing the improvement of the producer gas quality (e.g., H2 and CO concentration, lower heating value) and process efficiency parameters with distinct solid materials; particularly, the application of concrete, synthetic fayalite and wood pellets chars, showed promising results. Finally, the economic viability of the integration of direct (air) biomass gasification processes in the pulp and paper industry was also shown, despite still lacking interest to potential investors. In this context, the role of government policies and appropriate economic instruments are of major relevance to increase the implementation of these projects.O consumo excessivo de combust√≠veis f√≥sseis para garantir as necessidades e interesses da sociedade conduziu √† emiss√£o de elevadas quantidades de gases com efeito de estufa nas √ļltimas d√©cadas, contribuindo significativamente para a maior amea√ßa ambiental do s√©culo XXI: Altera√ß√Ķes Clim√°ticas. A solu√ß√£o para este desastre de origem humana √© de car√°ter complexo e s√≥ pode ser atingida atrav√©s da coopera√ß√£o de todos os governos e partes interessadas. Para isto, √© obrigat√≥ria a cria√ß√£o de uma bioeconomia como base de um futuro mais sustent√°vel, cujas necessidades energ√©ticas e materiais sejam garantidas pelas eternas energias da natureza (e.g., vento, sol). Neste sentido, a biomassa pode ter um papel principal como uma mat√©ria prima ajust√°vel e renov√°vel que permite a substitui√ß√£o de combust√≠veis f√≥sseis num variado n√ļmero de aplica√ß√Ķes, e a sua convers√£o atrav√©s da gasifica√ß√£o pode ser a chave para este prop√≥sito. Afinal, na pr√°tica, os combust√≠veis f√≥sseis s√£o apenas biomassa sujeita a elevada temperatura e press√£o durante milh√Ķes de anos. Al√©m do mais, a gest√£o eficaz da biomassa √© fundamental para a redu√ß√£o dos riscos de inc√™ndio florestal e, como tal, temos o dever de utilizar e valorizar este recurso. Neste trabalho, foi obtido novo conhecimento cient√≠fico para suporte do desenvolvimento das tecnologias de gasifica√ß√£o direta (ar) de biomassa em leitos fluidizados borbulhantes para produ√ß√£o de g√°s combust√≠vel, com o objetivo da substitui√ß√£o de g√°s natural em queimadores industriais. Este √© o primeiro passo para o desenvolvimento de biorrefinarias de gasifica√ß√£o, uma potencial futura ind√ļstria que ir√° providenciar um variado n√ļmero de produtos de valor acrescentado atrav√©s da biomassa e competir com a atual ind√ļstria petroqu√≠mica. Neste sentido, foram analisadas v√°rias medidas para a melhoria da qualidade do g√°s produto bruto e dos par√Ęmetros de efici√™ncia do processo. Em primeiro, a adi√ß√£o de vapor sobreaquecido como medida prim√°ria permitiu o aumento da concentra√ß√£o de H2 e da raz√£o molar H2/CO no g√°s produto sem comprometer a estabilidade do processo. No entanto, esta medida somente revelou potencial para a gasifica√ß√£o direta (ar) de biomassa de alta densidade (e.g., pellets) devido √† necessidade da acumula√ß√£o de carbonizados no leito do reator para a ocorr√™ncia de rea√ß√Ķes de reforma com vapor. Em segundo, a mistura de combust√≠veis derivados de res√≠duos e biomassa residual florestal permitiu a melhoria dos produtos de gasifica√ß√£o, constituindo desta forma uma estrat√©gia bastante promissora a n√≠vel econ√≥mico e ambiental, devido √† elevada abund√Ęncia e baixo custo dos res√≠duos urbanos. Contudo, devem ser efetuadas an√°lises t√©cnico-econ√≥micas e de ciclo de vida para a completa carateriza√ß√£o do processo. Em terceiro, a aplica√ß√£o de catalisadores de baixo custo como medida prim√°ria demonstrou elevado potencial para a melhoria do g√°s produto (e.g., concentra√ß√£o de H2 e CO, poder calor√≠fico inferior) e para o incremento dos par√Ęmetros de efici√™ncia do processo; em particular, a aplica√ß√£o de bet√£o, faialite sint√©tica e carbonizados de pellets de madeira, demonstrou resultados promissores. Finalmente, foi demonstrada a viabilidade econ√≥mica da integra√ß√£o do processo de gasifica√ß√£o direta (ar) de biomassa na ind√ļstria da pasta e papel, apesar dos par√Ęmetros determinados n√£o serem atrativos para potenciais investidores. Neste contexto, a interven√ß√£o dos governos e o desenvolvimento de instrumentos de apoio econ√≥mico √© de grande relev√Ęncia para a implementa√ß√£o destes projetos.Este trabalho foi financiado pela The Navigator Company e por Fundos Nacionais atrav√©s da Funda√ß√£o para a Ci√™ncia e a Tecnologia (FCT).Programa Doutoral em Engenharia da Refina√ß√£o, Petroqu√≠mica e Qu√≠mic

    Pastoralists and Predators in Alai: Political Ecology of Wildlife Management in Kyrgyzstan

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    The study is devoted to the human-environmental relationships in the post-socialist period of Kyrgyzstan. It addresses the human-wildlife conflicts using the example of the Alai Valley in the south of the country. Environmental and climatic characteristics of this highland valley provide suitable conditions for pastoralism and serve as habitat for wildlife. In recent decades, the natural landscape of the region came under increasing international attention with regard to nature conservation, sustainable land management and development projects. Historically, pastoralism has played a significant role for the economy of Kyrgyzstan. Following the dissolution of the Soviet Union, the collapse of state agricultural infrastructure facilities, veterinary care, loss of markets, and privatisation of the agricultural sector of the economy and other factors have led to a major downfall in the animal husbandry industry. The number of sheep and goats decreased from ten million in 1990 to four million in 2000. Nevertheless, pastoralism has considerable importance to the national economy and remains as the crucial income source for rural livelihoods in Kyrgyzstan. The post-socialist period of Kyrgyzstan has faced rapid socio-economic and political transformation which has resulted in changes not only to local livelihoods, but also in livestock husbandry, nature protection and wildlife management. In recent decades many pastoralists often complain about the increase in livestock depredation by wild predators. It is taking place despite the presence of state sponsored predator-control activity. From another side, there are public concerns about wildlife conservation. With the engagement of many environmental NGOs and mass-media, wildlife management issues have quickly become highly politicised in Kyrgyzstan. Becoming a Party to several global environmental conventions has increased the realisation of many projects funded by external donor organisations, and the implementation of their obligations for wildlife conservation, together, have substantially raised the profile of wildlife management in Kyrgyzstan at the international level. Moreover, since the independence of Kyrgyzstan, the territory of Protected Areas has increased by three times. Protected Areas are crucial to wildlife conservation and are promoted by the nature conservation community as a beneficial measure to the mitigation of human-wildlife conflicts. Despite this fact, livestock depredation by wild predators generates conflicts and has become a serious conservation issue. The study aims to better understand human-wildlife interrelationships in connection with pastoralism, protected areas and wildlife management in Kyrgyzstan. Wildlife related conflicts are analysed to determine the status of livestock depredation and to explore its linkages with rural livelihoods and wildlife conservation concerns in the Republic. The project design emphasises different utilisation strategies for the same area of rangelands, including the provision of fodder resources, wildlife habitat area, livestock grazing, and other uses by humans. Additionally, the focus of this study is directed towards a historical aspect of the region in relation to the development processes in the Alai Valley and use of its natural resources

    CITIES: Energetic Efficiency, Sustainability; Infrastructures, Energy and the Environment; Mobility and IoT; Governance and Citizenship

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    This book collects important contributions on smart cities. This book was created in collaboration with the ICSC-CITIES2020, held in San José (Costa Rica) in 2020. This book collects articles on: energetic efficiency and sustainability; infrastructures, energy and the environment; mobility and IoT; governance and citizenship

    Drugs from Marine Sources

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    Thanks to their rich chemodiversity, marine natural products represent a unique source of new bioactive metabolites. As the new leading compounds in drug discovery and development, these molecules may represent challenges for the treatment of a number of human diseases, attracting the attention of many researchers during their chemical and biological studies. This Special Issue covers all fields of drugs research in which marine natural products are involved, including their isolation and characterization, biological activities, and medicinal applications as well as synthetic approaches and their related analogues. The cover picture shows ‚ÄúThe Nudibranch mollusk Godiva quadricolor on a sponge, reflected under the surface during the low tide. Fusaro Lagoon, Bacoli (Naples)‚ÄĚ
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