“In-situ” generation of aluminum nanoparticles in a PP matrix

Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BD/39085/2007, PPCDT/AMB/61155/200

Effect of weathering conditions on the degradation behaviour of ABS

Fundação para a Ciência e a Tecnologia (FCT) - Bolsa de Doutoramento SFRH/BDE/15657/2007Poliversal – Plásticos e Tecnologia, S.A

Quality in management accounting: approach by activities in large companies

This study intends to contribute to the knowledge about the approach by activities, a management accounting method that promotes the quality of information. As specific objectives we have identified the following: to analyze the knowledge rate regarding the approach by activities, and identify whether there is a link between it and the financial officers’ characteristics; to analyze the utilization rate of the approach by activities, and the factors conditioning it; to analyze whether there is a link between a company’s features, and the use of the approach by activities. The data collection method used was the application of a survey to the financial officers of the largest Portuguese companies, which yielded 61 valid responses. The results found allowed us to conclude the following: the Time Driven Activity Based Costing is very little known and used in Portugal; there is a link between the knowledge of the approach by activities and the financial officers’ gender, age and educational background; there is a link between the use of the approach by activities and two company features: the legal form and the capital holding.info:eu-repo/semantics/acceptedVersio

Phosphorus removal from eutrophic waters with a polymer nanocomposite containing aluminium

Intensive agriculture production and industrial expansion are causing an increase on nutrient release (phosphorus and nitrogen), resulting in over-enrichment of soils and aquatic bodies. The nutrient over-enrichment of aquatic ecosystems leads to an excessive biomass growth. Eutrophication processes have negative effects on biology, chemistry and human use of lakes and rivers, namely by cyanobacteria toxins release. The Water Framework Directive set a tight schedule for water quality recovery and in order to implement a scientific based policy for eutrophication remediation and to attain a good water status, prospective scenarios are being considered in decision making processes [1]. Based on biogeochemical models, the need to lower phosphorus concentration on surface waters and to avoid phosphorus impact from resolubilisation processes are seen as mandatory [2]. One of most common water quality treatment strategies is based on chemicals addition to promote phosphorus precipitation [3]. However, these methods may be a source of ecological contamination with sludge production problems. Moreover, being phosphates a non-renewable source, the recovery and recycling of phosphorus is essential. Therefore, the present work concerned the removal and recovery of phosphorus from water using a new developed polymer nanocomposite containing aluminium nanoparticles (HPN). The results point that this new material removes 0.80±0.01 mgP/g in a pH interval between 2.0 and 6.5. Moreover, it could be regenerated using an HCl dilute solution. The issues that contribute mostly to the attractiveness of HPN-Pr as phosphorus sorbent are its moderate removal capacity, production process feasible at industrial scale, reuse after regeneration and recovery of phosphorus. The results obtained indicate that this material is a efficient alternative to solve the eutrophic problem

The image of and the interest in the accounting profession: an empirical study in three social groups

This study has the following goals: to analyse the image of and the interest in the accounting profession; to identify any possible differences in perception among the respondent groups; to identify the individual characteristics influencing the perception; to propose an explanatory model of the interest in the profession. The respondents were the members of three social groups composing the profession’s value chain: 105 financial officers of the biggest 500 Portuguese companies; 412 chartered accountants; 235 students majoring in Accounting. The data collected show that there are not any significant differences in perception regarding the image of and the interest in the accounting profession. Regarding the influence of the individual characteristics, the results obtained lead to the following conclusion: the third-year students with a higher average perceive a higher level of interest in the profession; the professionals with a higher academic degree and college graduated perceive a lower level of interest in the profession.info:eu-repo/semantics/acceptedVersio

TRANSIENT MODEL OF A STATIC EVAPORATOR FOR AN AIR-WATER HEAT PUMP

The increasing demand of electric energy in Brazil, allied to the great consumption in rush hour, has stimulated the study of water heating systems that substitute the electric shower. One of these equipments, the solar collector, is the most viable, with the best cost-benefits relation, because Brazil is a tropical country. A heat pump can be used as a support to solar collectors in places where the climatic conditions and/or the lack of available area of solar collection limit the use of the system. One way to improve this heat pump would be the substitution of its conventional evaporator for a static evaporator. This evaporator is constituted of a metallic plate with conformed canals, inside of which the coil is fixed through which the refrigerator cooling of the heat pump flows. The objective of this paper is the development of a mathematical model in transient regimen to simulate the static evaporator operation of an air-water heat pump. Some simulations had been carried through, that had allowed testing geometric parameters of the system, materials for the pipes and plates and different weather conditions. These computational tests had indicated that the model represents a good tool to project static evaporators

Electronic properties and hyperfine fields of nickel-related complexes in diamond

We carried out a first principles investigation on the microscopic properties of nickel-related defect centers in diamond. Several configurations, involving substitutional and interstitial nickel impurities, have been considered either in isolated configurations or forming complexes with other defects, such as vacancies and boron and nitrogen dopants. The results, in terms of spin, symmetry, and hyperfine fields, were compared with the available experimental data on electrically active centers in synthetic diamond. Several microscopic models, previously proposed to explain those data, have been confirmed by this investigation, while some models could be discarded. We also provided new insights on the microscopic structure of several of those centers.Comment: 21 pages, 8 figure

Phosphorous removal from water by polyolefins: effect of Al2O3 addition

Phosphorus is the main nutrient responsible for eutrophication of aquatic ecosystems, therefore it is important to develop new processes to remove phosphorus that avoid the formation of precipitates. Polyolefins with and without prior activation with aluminum oxide (Al2O3), processed as flat plates, were investigated for phosphate removal from an aqueous solution. The maximum amount of phosphorus removal was 0.042 μgP/cm2 for PE (polyethylene), 0.049 μgP/cm2 for PE-g-MA (polyethylene grafted with maleic anhydride), and 0.071 μgP/cm2 for PE-g-MAe (PE-g-MA enriched in MA). Increasing polyolefins’ polarity did not result in a significant increase in phosphate removal. Activated polyolefins with Al2O3 presented maximum amounts of phosphorus removal of 0.863 μgP/cm2 for PE, 0.948 μgP/cm2 for PE-g-MA, and 0.884 μgP/cm2 for PE-g-MAe. As expected, addition of Al2O3 considerably increased phosphate removal. In kinetic experiments carried out with polyolefins activated with Al2O3 during 3 months a very high percentage of phosphorus removal was obtained for (> 90 %) as well as a very low remaining phosphorus concentration in solution (< 10 μgP/L). As a conclusion, polyolefins activated with Al2O3 effectively removed phosphorous from aqueous solutions with low concentrations which indicate that this material might be used for in-situ remediation of eutrophic waters. The possibility to recover the material after use to recycle phosphate and the absence of precipitates’ formation are two major advantages of this process.Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BD/39085/2007