Modelling the Contribution of 40K, 232Th and 226Ra to Radiation Dose and Risk from Airborne Discharges of Coal-Fired Power Plants

Coal contains trace elements and naturally occurring radionuclides such as 40K, 232Th, 238U. When coal is burned, minerals, including most of the radionuclides, do not burn and concentrate in the ash several times in comparison with their content in coal. Usually, a small fraction of the fly ash produced (2-5%) is released into the atmosphere. The activities released depend on many factors (concentration in coal, ash content and inorganic matter of the coal, combustion temperature, ratio between bottom and fly ash, filtering system). Therefore, marked differences should be expected between the by-products produced and the amount of activity discharged (per unit of energy produced) from different coal-fired power plants. In fact, the effects of these releases on the environment due to ground deposition have been received some attention but the results from these studies are not unanimous and cannot be understood as a generic conclusion for all coal-fired power plants. In this study, the dispersion modelling of natural radionuclides was carried out to assess the impact of continuous atmospheric releases from a selected coal plant. The natural radioactivity of the coal and the fly ash were measured and the dispersion was modelled by a Gaussian plume estimating the activity concentration at different heights up to a distance of 20 km in several wind directions. External and internal doses (inhalation and ingestion) and the resulting risk were calculated for the population living within 20 km from the coal plant. In average, the effective dose is lower than the ICRP’s limit and the risk is lower than the U.S. EPA’s limit. Therefore, in this situation, the considered exposure does not pose any risk. However, when considering the dispersion in the prevailing wind direction, these values are significant due to an increase of 232Th and 226Ra concentrations in 75% and 44%, respectively.

Valorização da Borra de Café: Otimização da Produção de Biodiesel por Catálise Enzimática

O decréscimo das reservas de petróleo e as consequências ambientais resultantes do recurso a combustíveis fósseis nos motores a diesel têm levado à procura de combustíveis alternativos. Esta pesquisa alicerçada nas fontes de energia renovável tornou-se essencial, face à crescente procura de energia e ao limitado fornecimento de combustíveis fósseis . Resíduos de óleo de cozinha, gordura animal, entre outros resíduos de origem biológica, tais como a borra de café, são exemplos de matérias-primas para a produção de biodiesel. A sua valorização tem interesse quer pela perspetiva ambiental, quer pela económica, pois aumenta não só a flexibilidade e diversificação das matérias-primas, mas também contribui para uma estabilidade de custos e alteração nas políticas agrícolas e de uso do solo. É neste contexto que se enquadra o biodiesel e a borra de café, pretendendo-se aqui efetuar o estudo da produção, à escala laboratorial, de biodiesel a partir da borra de café, por transesterificação enzimática, visando a procura das melhores condições reacionais. Iniciando-se com a caracterização da borra de café, foram avaliados antes e após a extração do óleo da borra de café, diversos parâmetros, de entre os quais se destacam: o teor de humidade (16,97% e 6,79%), teor de cinzas (1,91 e 1,57%), teor de azoto (1,71 e 2,30%), teor de proteínas (10,7 e 14,4%), teor de carbono (70,2 e 71,7%), teor de celulose bruta (14,77 e 18,48%), teor de lenhina (31,03% e 30,97%) e poder calorifico superior (19,5 MJ/kg e 19,9 MJ/kg). Sumariamente, constatou-se que os valores da maioria dos parâmetros não difere substancialmente dos valores encontrados na literatura, tendo sido evidenciado o potencial da utilização desta biomassa, como fonte calorifica para queima e geração de energia. Sendo a caracterização do óleo extraído da borra de café um dos objetivos antecedentes à produção do biodiesel, pretendeu-se avaliar os diferentes parâmetros mais significativos. No que diz respeito à caracterização do óleo extraído, distingue-se a sua viscosidade cinemática (38,04 mm2/s), densidade 0,9032 g/cm3, poder calorífico de 37,9 kcal/kg, índice de iodo igual a 63,0 gI2/ 100 g óleo, o teor de água do óleo foi de 0,15 %, o índice de acidez igual a 44,8 mg KOH/g óleo, ponto de inflamação superior a 120 ºC e teor em ácidos gordos de 82,8%. Inicialmente foram efetuados ensaios preliminares, a fim de selecionar a lipase (Lipase RMIM, TL 100L e CALB L) e álcool (metanol ou etanol puros) mais adequados à produção de biodiesel, pelo que o rendimento de 83,5% foi obtido através da transesterificação mediada pela lipase RMIM, utilizando como álcool o etanol. Sendo outro dos objetivos a otimização do processo de transesterificação enzimática, através de um desenho composto central a três variáveis (razão molar etanol: óleo, concentração de enzima e temperatura), recorrendo ao software JMP 8.0, determinou-se como melhores condições, uma razão molar etanol: óleo 5:1, adição de 4,5% (m/m) de enzima e uma temperatura de 45 ºC, que conduziram a um rendimento experimental equivalente a 96,7 % e teor de ésteres 87,6%. Nestas condições, o rendimento teórico foi de 99,98%. Procurou-se ainda estudar o efeito da adição de água ao etanol, isto é, o efeito da variação da concentração do etanol pela adição de água, para teores de etanol de 92%, 85% e 75%. Verificou-se que até 92% decorreu um aumento da transesterificação (97,2%) para um teor de ésteres de (92,2%), pelo que para teores superiores de água adicionada (75% e 85%) ocorreu um decréscimo no teor final em ésteres (77,2% e 89,9%) e no rendimento da reação (84,3% e 91,9%). Isto indica a ocorrência da reação de hidrólise em maior extensão, que leva ao desvio do equilíbrio no sentido contrário à reação de formação dos produtos, isto é, dos ésteres. Finalmente, relativamente aos custos associados ao processo de produção de biodiesel, foram estimados para o conjunto de 27 ensaios realizados neste trabalho, e que corresponderam a 767,4 g de biodiesel produzido, sendo o custo dos reagentes superior ao custo energético, de 156,16 € e 126,02 €, respetivamente. Naturalmente que não esperamos que, a nível industrial os custos sejam desta ordem de grandeza, tanto mais que há economia de escala e que as enzimas utilizadas no processo deveriam ser reutilizadas diversas vezes.

Angolan cymbopogon citratus used for therapeutic benefits: nutritional composition and influence of solvents in phytochemicals content and antioxidant activity of leaf extracts

Folk medicine is a relevant and effective part of indigenous healthcare systems which are, in practice, totally dependent on traditional healers. An outstanding coincidence between indigenous medicinal plant uses and scientifically proved pharmacological properties of several phytochemicals has been observed along the years. This work focused on the leaves of a medicinal plant traditionally used for therapeutic benefits (Angolan Cymbopogon citratus), in order to evaluate their nutritional value. The bioactive phytochemical composition and antioxidant activity of leaf extracts prepared with different solvents (water, methanol and ethanol) were also evaluated. The plant leaves contained ~60% of carbohydrates, protein (~20%), fat (~5%), ash (~4%) and moisture (~9%). The phytochemicals screening revealed the presence of tannins, flavonoids, and terpenoids in all extracts. Methanolic extracts also contained alkaloids and steroids. Several methods were used to evaluate total antioxidant capacity of the different extracts (DPPH; NO; and H2O2 scavenging assays, reducing power, and FRAP). Ethanolic extracts presented a significantly higher antioxidant activity (p < 0.05) except for FRAP, in which the best results were achieved by the aqueous extracts. Methanolic extracts showed the lowest radical scavenging activities for both DPPH; and NO; radicals.

Content adaptation for an adaptive hypermedia system

The aim of this paper is presenting the recommendation module of the Mathematics Collaborative Learning Platform (PCMAT). PCMAT is an Adaptive Educational Hypermedia System (AEHS), with a constructivist approach, which presents contents and activities adapted to the characteristics and learning style of students of mathematics in basic schools. The recommendation module is responsible for choosing different learning resources for the platform, based on the user's characteristics and performance. Since the main purpose of an adaptive system is to provide the user with content and interface adaptation, the recommendation module is integral to PCMAT’s adaptation model.

Lipid content of frozen fish: comparison of different extraction methods and variability during freezing storage

In this work, a microwave-assisted extraction (MAE) methodology was compared with several conventional extraction methods (Soxhlet, Bligh & Dyer, modified Bligh & Dyer, Folch, modified Folch, Hara & Radin, Roese-Gottlieb) for quantification of total lipid content of three fish species: horse mackerel (Trachurus trachurus), chub mackerel (Scomber japonicus), and sardine (Sardina pilchardus). The influence of species, extraction method and frozen storage time (varying from fresh to 9 months of freezing) on total lipid content was analysed in detail. The efficiencies of methods MAE, Bligh & Dyer, Folch, modified Folch and Hara & Radin were the highest and although they were not statistically different, differences existed in terms of variability, with MAE showing the highest repeatability (CV = 0.034). Roese-Gottlieb, Soxhlet, and modified Bligh & Dyer methods were very poor in terms of efficiency as well as repeatability (CV between 0.13 and 0.18).

Lipid content and fatty acid profile of Senegalese sole (Solea senegalensis Kaup, 1858) juveniles as affected by feed containing different amounts of plant protein sources

A growth trial with Senegalese Sole (Solea senegalensis Kaup, 1858) juveniles fed with diets containing increasing replacement levels of fishmeal by mixtures of plant protein sources was conducted over 12 weeks. Total fat contents of muscle, liver, viscera, skin, fins and head tissues were determined, as well as fatty acid profiles of muscle and liver (GC-FID analysis). Liver was the preferential local for fat deposition (5.5–10.8% of fat) followed by fins (3.4–6.7% fat). Increasing levels of plant protein in the diets seems to be related to increased levels of total lipids in the liver. Sole muscle is lean (2.4–4.0% fat), with total lipids being similar among treatments. Liver fatty acid profile varied significantly among treatments. Plant protein diets induced increased levels of C16:1 and C18:2 n -6 and a decrease in ARA and EPA levels. Muscle fatty acid profile also evidenced increasing levels of C18:2 n 6, while ARA and DHA remained similar among treatments. Substitution of fishmeal by plant protein is hence possible without major differences on the lipid content and fatty acid profile of the main edible portion of the fish – the muscle.

Salt content in bread and dough from northern Portugal: method development and comparison

In the initial stage of this work, two potentiometric methods were used to determine the salt (sodium chloride) content in bread and dough samples from several cities in the north of Portugal. A reference method (potentiometric precipitation titration) and a newly developed ion-selective chloride electrode (ISE) were applied. Both methods determine the sodium chloride content through the quantification of chloride. To evaluate the accuracy of the ISE, bread and respective dough samples were analyzed by both methods. Statistical analysis (0.05 significance level) indicated that the results of these methods did not differ significantly. Therefore the ISE is an adequate alternative for the determination of chloride in the analyzed samples. To compare the results of these chloride-based methods with a sodium-based method, sodium was quantified in the same samples by a reference method (atomic absorption spectrometry). Significant differences between the results were verified. In several cases the sodium chloride content exceeded the legal limit when the chloride-based methods were used, but when the sodium-based method was applied this was not the case. This could lead to the erroneous application of fines and therefore the authorities should supply additional information regarding the analytical procedure for this particular control.

Comparing the content of instruments assessing environmental factors using the International Classification of Functioning, Disability and Health

Purpose: To describe and compare the content of instruments that assess environmental factors using the International Classification of Functioning, Disability and Health (ICF). Methods: A systematic search of PubMed, CINAHL and PEDro databases was conducted using a pre-determined search strategy. The identified instruments were screened independently by two investigators, and meaningful concepts were linked to the most precise ICF category according to published linking rules. Results: Six instruments were included, containing 526 meaningful concepts. Instruments had between 20% and 98% of items linked to categories in Chapter 1. The highest percentage of items from one instrument linked to categories in Chapters 2–5 varied between 9% and 50%. The presence or absence of environmental factors in a specific context is assessed in 3 instruments, while the other 3 assess the intensity of the impact of environmental factors. Discussion: Instruments differ in their content, type of assessment, and have several items linked to the same ICF category. Most instruments primarily assess products and technology (Chapter 1), highlighting the need to deepen the discussion on the theory that supports the measurement of environmental factors. This discussion should be thorough and lead to the development of methodologies and new tools that capture the underlying concepts of the ICF.

Soil remediation time to achieve clean-up goals I: influence of soil water content

The current models are not simple enough to allow a quick estimation of the remediation time. This work reports the development of an easy and relatively rapid procedure for the forecasting of the remediation time using vapour extraction. Sandy soils contaminated with cyclohexane and prepared with different water contents were studied. The remediation times estimated through the mathematical fitting of experimental results were compared with those of real soils. The main objectives were: (i) to predict, through a simple mathematical fitting, the remediation time of soils with water contents different from those used in the experiments; (ii) to analyse the influence of soil water content on the: (ii1) remediation time; (ii2) remediation efficiency; and (ii3) distribution of contaminants in the different phases present into the soil matrix after the remediation process. For sandy soils with negligible contents of clay and natural organic matter, artificially contaminated with cyclohexane before vapour extraction, it was concluded that (i) if the soil water content belonged to the range considered in the experiments with the prepared soils, then the remediation time of real soils of similar characteristics could be successfully predicted, with relative differences not higher than 10%, through a simple mathematical fitting of experimental results; (ii) increasing soil water content from 0% to 6% had the following consequences: (ii1) increased remediation time (1.8–4.9 h, respectively); (ii2) decreased remediation efficiency (99–97%, respectively); and (ii3) decreased the amount of contaminant adsorbed onto the soil and in the non-aqueous liquid phase, thus increasing the amount of contaminant in the aqueous and gaseous phases.

Remediation efficiency of vapour extraction of sandy soils contaminated with cyclohexane: influence of air flow rate, water and natural organic matter content

Abstract This work reports the analysis of the efficiency and time of soil remediation using vapour extraction as well as provides comparison of results using both, prepared and real soils. The main objectives were: (i) to analyse the efficiency and time of remediation according to the water and natural organic matter content of the soil; and (ii) to assess if a previous study, performed using prepared soils, could help to preview the process viability in real conditions. For sandy soils with negligible clay content, artificially contaminated with cyclohexane before vapour extraction, it was concluded that (i) the increase of soil water content and mainly of natural organic matter content influenced negatively the remediation process, making it less efficient, more time consuming, and consequently more expensive; and (ii) a previous study using prepared soils of similar characteristics has proven helpful for previewing the process viability in real conditions.

B2B platform for media content personalisation

This paper proposes a novel business model to support media content personalisation: an agent-based business-to-business (B2B) brokerage platform for media content producer and distributor businesses. Distributors aim to provide viewers with a personalised content experience and producers wish to en-sure that their media objects are watched by as many targeted viewers as possible. In this scenario viewers and media objects (main programmes and candidate objects for insertion) have profiles and, in the case of main programme objects, are annotated with placeholders representing personalisation opportunities, i.e., locations for insertion of personalised media objects. The MultiMedia Brokerage (MMB) platform is a multiagent multilayered brokerage composed by agents that act as sellers and buyers of viewer stream timeslots and/or media objects on behalf of the registered businesses. These agents engage in negotiations to select the media objects that best match the current programme and viewer profiles.

How to integrate stories and ICT in content-based units of work for English learning

The aim of this article is to show how it is possible to integrate stories and ICT in Content Language Integrated Learning (CLIL) for English as a foreign language (EFL) learning in bilingual schools. Two Units of Work are presented. One, for the second year of Primary, is based on a Science topic, ‘Materials’. The story used is ‘The three little pigs’ and the computer program ‘JClic’. The other one is based on a Science and Arts topic for the sixth year of Primary, the story used is ‘Charlotte’s Web’ and the computer program ‘Atenex’.

EduMCA: an approach to Educational Mobile Content Adaptation

As the variety of mobile devices connected to the Internet growts there is a correponding increase in the need to deliver content tailored to their heterogeneous characteristics. At the same time, we watch to the increase of e-learning in universities through the adoption of electronic platforms and standards. Not surprisingly, the concept of mLearning (Mobile Learning) appeared in recent years decreasing the limitation of learning location with the mobility of general portable devices. However, this large number and variety of Web-enabled devices poses several challenges for Web content creators who want to automatic get the delivery context and adapt the content to the client mobile devices. In this paper we analyze several approaches to defining delivery context and present an architecture for deliver uniform mLearning content to mobile devices denominated eduMCA - Educational Mobile Content Adaptation. With the eduMCA system the Web authors will not need to create specialized pages for each kind of device, since the content is automatically transformed to adapt to any mobile device capabilities from WAP to XHTML MP-compliant devices.

Using mobile device detection approaches to augment the accuracy of web delivery content

Recent studies of mobile Web trends show a continuous explosion of mobile-friendly content. However, the increasing number and heterogeneity of mobile devices poses several challenges for Web programmers who want to automatically get the delivery context and adapt the content to mobile devices. In this process, the devices detection phase assumes an important role where an inaccurate detection could result in a poor mobile experience for the enduser. In this paper we compare the most promising approaches for mobile device detection. Based on this study, we present an architecture for a system to detect and deliver uniform m-Learning content to students in a Higher School. We focus mainly on the devices capabilities repository manageable and accessible through an API. We detail the structure of the capabilities XML Schema that formalizes the data within the devices capabilities XML repository and the REST Web Service API for selecting the correspondent devices capabilities data according to a specific request. Finally, we validate our approach by presenting the access and usage statistics of the mobile web interface of the proposed system such as hits and new visitors, mobile platforms, average time on site and rejection rate.

Using the Common Cartridge profile to enhance learning content interoperability

The concept of Learning Object (LO) is crucial for the standardization on eLearning. The latest LO standard from IMS Global Learning Consortium is the IMS Common Cartridge (IMS CC) that organizes and distributes digital learning content. By analyzing this new specification we considered two interoperability levels: content and communication. A common content format is the backbone of interoperability and is the basis for content exchange among eLearning systems. Communication is more than just exchanging content; it includes also accessing to specialized systems and services and reporting on content usage. This is particularly important when LOs are used for evaluation. In this paper we analyze the Common Cartridge profile based on the two interoperability levels we proposed. We detail its data model that comprises a set of derived schemata referenced on the CC schema and we explore the use of the IMS Learning Tools Interoperability (LTI) to allow remote tools and content to be integrated into a Learning Management System (LMS). In order to test the applicability of IMS CC for automatic evaluation we define a representation of programming exercises using this standard. This representation is intended to be the cornerstone of a network of eLearning systems where students can solve computer programming exercises and obtain feedback automatically. The CC learning object is automatically generated based on a XML dialect called PExIL that aims to consolidate all the data need to describe resources within the programming exercise life-cycle. Finally, we test the generated cartridge on the IMS CC online validator to verify its conformance with the IMS CC specification.