Assessment of the environmental radiation by in situ gamma ray spectrometry

Naturally occurring radioactive materials (NORM) under certain conditions can reach hazardous radiological levels contributing to an additional exposure dose to ionizing radiation. Most environmental concerns are associated with uranium mining and milling sites, but the same concerns should be addressed to natural near surface occurrences of uranium as well as man-made sources such as technologically enhanced naturally occurring radioactive materials (TENORM) resulting from phosphates industry, ceramic industry and energy production activities, in particular from coal-fired power plants which is one of the major sources of increased exposure to man from enhanced naturally occurring materials. This work describes the methodology developed to assess the environmental radiation by in situ gamma spectrometry in the vicinity of a Portuguese coal fired power plant. The current investigation is part of a research project that is undergoing in the vicinity of Sines Coal-Fired Power Plant (south of Portugal) until the end of 2013.

Radiological impact associated to Technologically Enhanced Naturally Occurring Radioactive Materials (TENORM) from coal-fired power plants emissions

Certain materials used and produced in a wide range of non-nuclear industries contain enhanced activity concentrations of natural radionuclides. In particular, electricity production from coal is one of the major sources of increased human exposure to naturally occurring radioactive materials. A methodology was developed to assess the radiological impact due to natural radiation background. The developed research was applied to a specific case study, the Sines coal-fired power plant, located in the southwest coastline of Portugal. Gamma radiation measurements were carried out with two different instruments: a sodium iodide scintillation detector counter (SPP2 NF, Saphymo) and a gamma ray spectrometer with energy discrimination (Falcon 5000, Canberra). Two circular survey areas were defined within 20 km of the power plant. Forty relevant measurements points were established within the sampling area: 15 urban and 25 suburban locations. Additionally, ten more measurements points were defined, mostly at the 20-km area. The registered gamma radiation varies from 20 to 98.33 counts per seconds (c.p.s.) corresponding to an external gamma exposure rate variable between 87.70 and 431.19 nGy/h. The highest values were measured at locations near the power plant and those located in an area within the 6 and 20 km from the stacks. In situ gamma radiation measurements with energy discrimination identified natural emitting nuclides as well as their decay products (Pb-212, Pb-2142, Ra-226, Th-232, Ac-228, Th-234, Pa-234, U- 235, etc.). According to the results, an influence from the stacks emissions has been identified both qualitatively and quantitatively. The developed methodology accomplished the lack of data in what concerns to radiation rate in the vicinity of Sines coal-fired power plant and consequently the resulting exposure to the nearby population.

Recycling of pultrusion production waste into innovative concrete-polymer composite solutions

In this study, the added value resultant from the incorporation of pultrusion production waste into polymer based concretes was assessed. For this purpose, different types of thermoset composite scrap material, proceeding from GFRP pultrusion manufacturing process, were mechanical shredded and milled into a fibrous-powdered material. Resultant GFRP recyclates, with two different size gradings, were added to polyester based mortars as fine aggregate and filler replacements, at various load contents between 4% up to 12% in weight of total mass. Flexural and compressive loading capacities were evaluated and found better than those of unmodified polymer mortars. Obtained results highlight the high potential of recycled GFRP pultrusion waste materials as efficient and sustainable admixtures for concrete and mortar-polymer composites, constituting an emergent waste management solution.

GFRP waste reinforced polymer mortars: a new waste management solution for GFRP scrap material

To date, glass fibre reinforced polymer (GFRP) waste recycling is very limited and restricted by thermoset nature of binder matrix and lack of economically viable enduse applications for the recyclates. In this study, efforts were made in order to recycle grinded GFRP waste proceeding from pultrusion production scrap, into new and sustainable composite materials. For this purpose, GFRP waste recyclates, a mix of powdered and fibrous materials, were incorporated into polyester based mortars as fine aggregate and filler replacements, at different load contents (between 4% up to 12% of total mass) and particle size distributions. Potential recycling solution was assessed by mechanical behaviour of resultant GFRP waste modified polymer mortars. Test results revealed that GFRP waste filled polymer mortars present improved flexural and compressive behaviour over unmodified polyester based mortars, thus indicating the feasibility of GFRP waste reuse in concrete-polymer composites.

Estratégias de tradução em sites das regiões de turismo de Portugal: estudo baseado em corpus

Em Portugal, o turismo é uma actividade económica que gera ganhos significativos e a promoção turística do país no mercado externo assenta cada vez mais na criação de sites multilingues. Este artigo examina um corpus constituído por textos provenientes de sites de Regiões de Turismo de Portugal, em português, e as respectivas traduções para inglês, com o objectivo de demonstrar o modo como os tradutores adicionam informação inexistente no texto original. Através da análise desta característica específica dos sites oficiais traduzidos para promover o destino ―Portugal‖ no mercado externo pretende salientar-se a importância que as estratégias de tradução assumem no marketing do destino turístico, uma vez que a informação adicionada cria uma determinada imagem de uma região. Em termos teóricos e metodológicos, este artigo enquadra-se no âmbito da Linguística de Corpus.

Estudo do óxido de cálcio como catalisador para a transesterificação de óleos alimentares usados

O instável mas tendencialmente crescente preço dos combustíveis associado a preocupações ambientais cada vez mais enraizadas nas sociedades, têm vindo a despoletar uma maior atenção à procura de combustíveis alternativos. Por outro lado, várias projecções indicam um aumento muito acentuado do consumo energético global no curto prazo, fruto do aumento da população e do nível de industrialização das sociedades. Neste contexto, o biodiesel (ésteres de ácidos gordos) obtido através da transesterificação de triglicerídeos de origem vegetal ou animal, surge como a alternativa “verde” mais viável para utilização em equipamentos de combustão. A reacção de transesterificação é catalisada, por norma com recurso a catalisadores homogéneos alcalinos (NaOH ou KOH). Este tipo de processo, o único actualmente com expressão a nível industrial, apresenta algumas desvantagens que, para além de aumentarem o custo do produto final, contribuem para reduzir a benignidade do mesmo: a impossibilidade de reutilização do catalisador, o aumento do número e complexidade das etapas de separação e a produção de efluentes resultantes das referidas etapas. Com o intuito de minimizar ou eliminar estes problemas, vários catalisadores heterogéneos têm vindo a ser estudados para esta reacção. Apesar de muitos apresentarem resultados promissores, a grande maioria não tem viabilidade para aplicação industrial seja devido ao seu próprio custo, seja devido aos pré-tratamentos necessários à sua utilização. Entre estes catalisadores, o óxido de cálcio é talvez o que apresenta resultados mais promissores. O crescente número de estudos envolvendo este catalisador em detrimento de outros, é por si mesmo prova do potencial do CaO. A realização deste trabalho pretendia atingir os seguintes objectivos principais: • Avaliar a elegibilidade do óxido de cálcio enquanto catalisador da reacção de transesterificação de óleos alimentares usados com metanol; • Avaliar qual a sua influência nas características dos produtos finais; • Avaliar as diferenças de performance entre o óxido de cálcio activado em atmosfera inerte (N2) e em ar, enquanto catalisadores da reacção de transesterificação de óleos alimentares usados com metanol; • Optimizar as condições da reacção com recurso às ferramentas matemáticas disponibilizadas pelo planeamento factorial, através da variação de quatro factores chave de influência: temperatura, tempo, relação metanol / óleo e massa de catalisador utilizado. O CaO utlizado foi obtido a partir de carbonato de cálcio calcinado numa mufla a 750 °C durante 3 h. Foi posteriormente activado a 900 °C durante 2h, em atmosferas diferentes: azoto (CaO-N2) e ar (CaO-Ar). Avaliaram-se algumas propriedades dos catalisadores assim preparados, força básica, concentração de centros activos e áreas específicas, tendo-se obtido uma força básica situada entre 12 e 14 para ambos os catalisadores, uma concentração de centros activos de 0,0698 mmol/g e 0,0629 mmol/g e áreas específicas de 10 m2/g e 11 m2/g respectivamente para o CaO-N2 e CaO-Ar. Efectuou-se a transesterificação, com catálise homogénea, da mistura de óleos usados utilizada neste trabalho com o objectivo de determinar os limites para o teor de FAME’s (abreviatura do Inglês de Fatty Acid Methyl Esters’) que se poderiam obter. Foi este o parâmetro avaliado em cada uma das amostras obtidas por catálise heterogénea. Os planos factoriais realizados tiveram como objectivo maximizar a sua quantidade recorrendo à relação ideal entre tempo de reacção, temperatura, massa de catalisador e quantidade de metanol. Verificou-se que o valor máximo de FAME’s obtidos a partir deste óleo estava situado ligeiramente acima dos 95 % (m/m). Realizaram-se três planos factoriais com cada um dos catalisadores de CaO até à obtenção das condições óptimas para a reacção. Não se verificou influência significativa da relação entre a quantidade de metanol e a massa de óleo na gama de valores estudada, pelo que se fixou o valor deste factor em 35 ml de metanol / 85g de óleo (relação molar aproximada de 8:1). Verificou-se a elegibilidade do CaO enquanto catalisador para a reacção estudada, não se tendo observado diferenças significativas entre a performance do CaO-N2 e do CaO-Ar. Identificaram-se as condições óptimas para a reacção como sendo os valores de 59 °C para a temperatura, 3h para o tempo e 1,4 % de massa de catalisador relativamente à massa de óleo. Nas referidas condições, obtiveram-se produtos com um teor de FAME’s de 95,7 % na catálise com CaO-N2 e 95,3 % na catálise com CaO-Ar. Alguns autores de estudos consultados no desenvolvimento do presente trabalho, referiam como principal problema da utilização do CaO, a lixiviação de cálcio para os produtos obtidos. Este facto foi confirmado no presente trabalho e na tentativa de o contornar, tentou-se promover a carbonatação do cálcio com a passagem de ar comprimido através dos produtos e subsequente filtração. Após a realização deste tratamento, não mais se observaram alterações nas suas propriedades (aparecimento de turvação ou precipitados), no entanto, nos produtos obtidos nas condições óptimas, a concentração de cálcio determinada foi de 527 mg/kg no produto da reacção catalisada com CaO-N2 e 475 mg/kg com CaO-A. O óxido de cálcio apresentou-se como um excelente catalisador na transesterificação da mistura de óleos alimentares usados utilizada no presente trabalho, apresentando uma performance ao nível da obtida por catálise homogénea básica. Não se observaram diferenças significativas de performance entre o CaO-N2 e o CaO-Ar, sendo possível obter nas mesmas condições reaccionais produtos com teores de FAME’s superiores a 95 % utilizando qualquer um deles como catalisador. O elevado teor de cálcio lixiviado observado nos produtos, apresenta-se como o principal obstáculo à aplicação a nível industrial do óxido de cálcio como catalisador para a transesterificação de óleos.

Novel Prostate Specific Antigen plastic antibody designed withcharged binding sites for an improved protein binding and itsapplication in a biosensor of potentiometric transduction

This work shows that the synthesis of protein plastic antibodies tailored with selected charged monomersaround the binding site enhances protein binding. These charged receptor sites are placed over a neutralpolymeric matrix, thus inducing a suitable orientation the protein reception to its site. This is confirmed bypreparing control materials with neutral monomers and also with non-imprinted template. This concepthas been applied here to Prostate Specific Antigen (PSA), the protein of choice for screening prostate can-cer throughout the population, with serum levels >10 ng/mL pointing out a high probability of associatedcancer.Protein Imprinted Materials with charged binding sites (C/PIM) have been produced by surfaceimprinting over graphene layers to which the protein was first covalently attached. Vinylben-zyl(trimethylammonium chloride) and vinyl benzoate were introduced as charged monomers labellingthe binding site and were allowed to self-organize around the protein. The subsequent polymerizationwas made by radical polymerization of vinylbenzene. Neutral PIM (N/PIM) prepared without orientedcharges and non imprinted materials (NIM) obtained without template were used as controls.These materials were used to develop simple and inexpensive potentiometric sensor for PSA. Theywere included as ionophores in plasticized PVC membranes, and tested over electrodes of solid or liq-uid conductive contacts, made of conductive carbon over a syringe or of inner reference solution overmicropipette tips. The electrodes with charged monomers showed a more stable and sensitive response,with an average slope of -44.2 mV/decade and a detection limit of 5.8 × 10−11mol/L (2 ng/mL). The cor-responding non-imprinted sensors showed lower sensitivity, with average slopes of -24.8 mV/decade.The best sensors were successfully applied to the analysis of serum, with recoveries ranging from 96.9to 106.1% and relative errors of 6.8%.

Haemoglobin smart plastic antibody material tailored with charged binding sites on silica nanoparticles: its application as an ionophore in potentiometric transduction

This work uses surface imprinting to design a novel smart plastic antibodymaterial (SPAM) for Haemoglobin (Hb). Charged binding sites are described here for the first time to tailor plastic antibody nanostructures for a large size protein such as Hb. Its application to design small, portable and low cost potentiometric devices is presented. The SPAM material was obtained by linking Hb to silica nanoparticles and allowing its ionic interaction with charged vinyl monomers. A neutral polymeric matrix was created around these and the imprinted protein removed. Additional materials were designed in parallel acting as a control: a neutral imprinted material (NSPAM), obtained by removing the charged monomers from the procedure, and the Non-Imprinted (NI) versions of SPAM and NSPAM by removing the template. SEM analysis confirmed the surface modification of the silica nanoparticles. All materials were mixed with PVC/plasticizer and applied as selective membranes in potentiometric transduction. Electromotive force (emf) variations were detected only for selective membranes having a lipophilic anionic additive in the membrane. The presence of Hb inside these membranes was evident and confirmed by FTIR, optical microscopy and Raman spectroscopy. The best performance was found for SPAM-based selective membranes with an anionic lipophilic additive, at pH 5. The limits of detection were 43.8 mg mL 1 and linear responses were obtained down to 83.8 mg mL 1, with an average cationic slope of +40 mV per decade. Good selectivity was also observed against other coexisting biomolecules. The analytical application was conducted successfully, showing accurate and precise results.

Smart Plastic Antibody Material for Hemoglobin Tailored by Silica Surface Imprinting and with Charged Binding Sites: Its use as Ionophore in Potentiometric Transduction

JORNADAS DE ELECTROQUÍMICA E INOVAÇÃO 2013

Sectors and routes in solid waste collection

Collecting and transporting solid waste is a constant problem for municipalities and populations in general. Waste management should take into account the preservation of the environment and the reduction of costs. The goal with this paper is to address a real-life solid waste problem. The case reveals some general and specific characteristics which are not rare, but are not widely addressed in the literature. Furthermore, new methods and models to deal with sectorization and routing are introduced, which can be extended to other applications. Sectorization and routing are tackled following a two-phase approach. In the first phase, a new method is described for sectorization based on electromagnetism and Coulomb’s Law. The second phase addresses the routing problems in each sector. The paper addresses not only territorial division, but also the frequency with which waste is collected, which is a critical issue in these types of applications. Special characteristics related to the number and type of deposition points were also a motivation for this work. A new model for a Mixed Capacitated Arc Routing Problem with Limited Multi-Landfills is proposed and tested in real instances. The computational results achieved confirm the effectiveness of the entire approach.

Waste collection routing-limited multiple landfills and heterogeneous fleet

This article deals with a real-life waste collection routing problem. To efficiently plan waste collection, large municipalities may be partitioned into convenient sectors and only then can routing problems be solved in each sector. Three diverse situations are described, resulting in three different new models. In the first situation, there is a single point of waste disposal from where the vehicles depart and to where they return. The vehicle fleet comprises three types of collection vehicles. In the second, the garage does not match any of the points of disposal. The vehicle is unique and the points of disposal (landfills or transfer stations) may have limitations in terms of the number of visits per day. In the third situation, disposal points are multiple (they do not coincide with the garage), they are limited in the number of visits, and the fleet is composed of two types of vehicles. Computational results based not only on instances adapted from the literature but also on real cases are presented and analyzed. In particular, the results also show the effectiveness of combining sectorization and routing to solve waste collection problems.

Electromagnetism based approach to Sector design in Waste Collection

For efficient planning of waste collection routing, large municipalities may be partitioned into convenient sectors. The real case under consideration is the municipality of Monção, in Portugal. Waste collection involves more than 1600 containers over an area of 220 km2 and a population of around 20,000 inhabitants. This is mostly a rural area where the population is distributed in small villages around the 33 boroughs centres (freguesia) that constitute the municipality. In most freguesias, waste collection is usually conducted 3 times a week. However, there are situations in which the same collection is done every day. The case reveals some general and specific characteristics which are not rare, but are not widely addressed in the literature. Furthermore, new methods and models to deal with sectorization and routing are introduced, which can be extended to other applications. Sectorization and routing are tackled following a three-phase approach. The first phase, which is the main concern of the presentation, introduces a new method for sectorization inspired by Electromagnetism and Coulomb’s Law. The matter is not only about territorial division, but also the frequency of waste collection, which is a critical issue in these types of applications. Special characteristics related to the number and type of deposition points were also a motivation for this work. The second phase addresses the routing problems in each sector: new Mixed Capacitated Arc Routing with Limited Multi-Landfills models will be presented. The last phase integrates Sectoring and Routing. Computational results confirm the effectiveness of the entire novel approach.