Use of swine waste-derived biogas to enhance microalgae productivity.

The effects of swine wastewater-derived biogas on microalgae productivity were determined. Experiments were conducted in a closed photobioreactor containing digestate effluent as culturing media and biogas in the headspaceas source of CO2. Experiments were carried out under mixothrophic and autothrophic conditions. Results showed that autotrophic growth rate (0.6 d-1)was twofoldfaster than mixotrophic. Frequent reinjections of biogas containing up to 2,000 ppm of hydrogen sulfide was not inhibitory to microalgae growth. The rapid removal of H2S in the system suggests photobioreactors can be an interesting alternative to biogas purification. A model to estimate microalgae productivity based on the amount of available CO2, inorganic and organic carbon was developedand showed good data fit correlation (r²= 0.99).

Implementação de uma solução open source de Business Intelligence com metodologia Ágil

A importância dos sistemas de data warehousing e business intelligence é cada vez mais pronunciada, no sentido de dotar as organizações com a capacidade de guardar, explorar e produzir informação de valor acrescido para os seus processos de tomada de decisão. Esta realidade é claramente aplicável aos sectores da administração pública portuguesa e, muito em particular, aos organismos com responsabilidades centrais no Ministério da Saúde. No caso dos Serviços Partilhados do Ministério da Saúde (SPMS), que tem como missão prover o SNS de sistemas centrais de business intelligence, o apelo dos seus clientes, para que possam contar com capacidades analíticas nos seus sistemas centrais, tem sido sentido de forma muito acentuada. Todavia, é notório que, tanto os custos, como a complexidade, de grande parte destes projetos têm representado uma séria ameaça à sua adoção e sucesso. Por um lado, a administração pública tem recebido um forte encorajamento para integrar e adotar soluções de natureza open source (modelo de licenciamento gratuito), para os seus projetos de sistemas de informação. Por outro lado, temos vindo a assistir a uma vaga de aceitação generalizada de novas metodologias de desenvolvimento de projetos informáticos, nomeadamente no que diz respeito às metodologias Agéis, que se assumem como mais flexíveis, menos formais e com maior grau de sucesso. No sentido de averiguar da aplicabilidade do open source e das metodologias Ágeis aos sistemas de business intelligence, este trabalho documenta a implementação de um projeto organizacional para a SPMS, com recurso a ferramentas open source de licenciamento gratuito e através de uma metodologia de desenvolvimento de natureza Ágil.

40 K Liquid Neon Energy Storage Unit

A thermal Energy Storage Unit (ESU) could be used to attenuate inherent temperature fluctuations of a cold finger, either from a cryocooler working or due to sudden income heat bursts. An ESU directly coupled to the cold source acts as a thermal buffer temporarily increasing its cooling capacity and providing a better thermal stability of the cold finger (“Power Booster mode”). The energy storage units presented here use an enthalpy reservoir based on the high latent heat of the liquid-vapour transition of neon in the temperature range 38 - 44 K to store up to 900 J, and that uses a 6 liters expansion volume at RT in order to work as a closed system. Experimental results in the power booster mode will be described: in this case, the liquid neon cell was directly coupled to the cold finger of the working cryocooler, its volume (12 cm3) allowing it to store 450 J at around 40 K. 10 W heat bursts were applied, leading to liquid evaporation, with quite reduced temperature changes. The liquid neon reservoir can also work as a temporary cold source to be used after stopping the cryocooler, allowing for a vibration-free environment. In this case the enthalpy reservoir implemented (24 cm3) was linked to the cryocooler cold finger through a gas gap heat switch for thermal coupling/decoupling of the cold finger. We will show that, by controlling the enthalpy reservoir’s pressure, 900 J can be stored at a constant temperature of 40 K as in a triple-point ESU.

Dimensions of source credibility in the case of user-generated advertisements

User-generated advertising changed the world of advertising and changed the strategies used by marketers. Many researchers explored the dimensions of source credibility in traditional media and online advertising. However, little previous research explored the dimensions of source credibility in the context of user-generated advertising. This exploratory study aims to investigate the different dimensions of source credibility in the case of user-generated advertising. More precisely, this study will explore the following factors: (1) objectivity, (2) trustworthiness, (3) expertise, (4) familiarity, (5) attractiveness and (6) frequency. The results suggest that some of the dimensions of source credibility (objectivity, trustworthiness, expertise, familiarity and attractiveness) remain the same in the case of user-generated advertising. Additionally, a new dimension is added to the factors that explain source credibility (reputation). Furthermore, the analysis suggests that the dimension “frequency” is not an explanatory factor of credibility in the case of user-generated advertisement. The study also suggests that companies using user-generated advertisement as part of their overall marketing strategy should focus on objectivity, trustworthiness, expertise, attractiveness and reputation when selecting users that will communicate sponsored user-generated advertisements.

Portuguese plain architecture: history opening a closed sequence

The paper will address George Kubler’s Portuguese Plain Architecture [PPA] (1972) and its effect in Portuguese architectural practice. Kubler’s philosophy of art history implied that closed sequences of objects could be opened by several reasons. Thus, it will be argued that there is an effect upon Portuguese architecture post 1974, that is apparent by the reemergence of some of the form classes treated by Kubler. This was mostly achieved through the popularity of Kubler’s book within architectural practice, scholarship and moreover by the establishment of the term “Plain Architecture” in portuguese architectural vocabulary. Plain Architecture of the seventeenth and eighteenth centuries shared some qualities with the architecture to be built in post‑revolutionary Portugal, most importantly the effect that could be achieved with low budget buildings that were responding to a situation of crisis, and simultaneously exhaled aristocratic sparsity. The connection of PPA with the ideological attributes of early modernism and the political context of the time catalysed the reemergence of a new order of Portuguese Plain that resonates still in contemporary architecture.

MANGROVE BARK: A RENEWABLE RESIN SOURCE FOR WOOD ADHESIVES

From four solutions tested to extract tannins from mangrove bark for wood adhesives, hot water is recommended. Hot water extracted 21.4% of formaldehyde-hydrochloric acid reactive polyphenols on oven-dry bark basis.

Comprehensive comparison of a current-source and a voltage-source converter for three-phase EV fast battery chargers

This paper presents a comprehensive comparison of a current-source converter and a voltage-source converter for three-phase electric vehicle (EV) fast battery chargers. Taking into account that the current-source converter (CSC) is a natural buck-type converter, the output voltage can assume a wide range of values, which varies between zero and the maximum instantaneous value of the power grid phase-to-phase voltage. On the other hand, taking into account that the voltage-source converter (VSC) is a natural boost-type converter, the output voltage is always greater than the maximum instantaneous value of the power grid phase-to-phase voltage, and consequently, it is necessary to use a dc-dc buck-type converter for applications as EV fast battery chargers. Along the paper is described in detail the principle of operation of both the CSC and the VSC for EV fast chargers, as well as the main equations of the power theory and current control strategies. The comparison between both converters is mainly established in terms of the total harmonic distortion of the grid current and the estimated efficiency for a range of operation between 10 kW and 50 kW.

Three-phase three-level current-source converter for EVs fast battery charging systems

This paper presents a three-phase three-level fast battery charger for electric vehicles (EVs) based in a current-source converter (CSC). Compared with the traditional voltage-source converters used for fast battery chargers, the CSC can be seen as a natural buck-type converter, i.e., the output voltage can assume a wide range of values, which varies between zero and the maximum instantaneous value of the power grid phase-to-phase voltage. Moreover, using the CSC it is not necessary to use a dc-dc back-end converter in the battery side, and it is also possible to control the grid current in order to obtain a sinusoidal waveform, and in phase with the power grid voltage (unitary power factor). Along the paper is described in detail the proposed CSC for EVs fast battery charging systems: the circuit topology, the power control theory, the current control strategy and the grid synchronization algorithm. Several simulation results of the EV fast battery charger operating with a maximum power of 50 kW are presented.

Predictive control of a current-source inverter for solar photovoltaic grid interface

Solar photovoltaic systems are an increasing option for electricity production, since they produce electrical energy from a clean renewable energy resource, and over the years, as a result of the research, their efficiency has been increasing. For the interface between the dc photovoltaic solar array and the ac electrical grid is necessary the use of an inverter (dc-ac converter), which should be optimized to extract the maximum power from the photovoltaic solar array. In this paper is presented a solution based on a current-source inverter (CSI) using continuous control set model predictive control (CCS-MPC). All the power circuits and respective control systems are described in detail along the paper and were tested and validated performing computer simulations. The paper shows the simulation results and are drawn several conclusions.

Three-phase current-source shunt active power filter with solar photovoltaic grid interface

This paper presents the proposal of a three phase current source shunt active power filter (CS-SAPF) with photovoltaic grid interface. The proposed system combines the compensation of reactive power and harmonics with the injection of energy from a solar photovoltaic array into the electrical power grid. The proposed equipment presents the advantage of giving good use to the current source inverter, even when the solar photovoltaic array is not producing energy. The paper describes the control system of the CS SAPF, the energy injection control strategy, and the current harmonics and power factor compensation strategy. Simulation results to assess the performance of the proposed system are also presented.

From a NoSQL data source to a business intelligence solution: An experiment

We are living in the era of Big Data. A time which is characterized by the continuous creation of vast amounts of data, originated from different sources, and with different formats. First, with the rise of the social networks and, more recently, with the advent of the Internet of Things (IoT), in which everyone and (eventually) everything is linked to the Internet, data with enormous potential for organizations is being continuously generated. In order to be more competitive, organizations want to access and explore all the richness that is present in those data. Indeed, Big Data is only as valuable as the insights organizations gather from it to make better decisions, which is the main goal of Business Intelligence. In this paper we describe an experiment in which data obtained from a NoSQL data source (database technology explicitly developed to deal with the specificities of Big Data) is used to feed a Business Intelligence solution.

Validation of a method to measure light distortion surrounding a source of glare

Our objective was to validate a new device dedicated to measure the light disturbances surrounding bright sources of light under different sources of potential variability. Twenty subjects were involved in the study. Light distortion was measured using an experimental prototype (light distortion analyzer, CEORLab, University of Minho, Portugal) comprising twenty-four LED arrays panel at 2 m. Sources of variability included: intrasession and intersession repeated measures, pupil size (3 versus 6 mm), defocus (þ0.50) correction for the working distance, angular resolution (15 deg versus 30 deg), temporal stimuli presentation, and pupil size. Size, shape, location, and irregularity parameters have been obtained. At a low speed of presentation of the stimuli, changes in angular resolution did not have an effect on the results of the parameters measured. Results did not change with pupil size. Intensity of the central glare source significantly influenced the outcomes. Examination time was reduced by 30% when a 30 deg angular resolution was explored instead of 15 deg. Measurements were fast and repeatable under the same experimental conditions. Size and shape parameters showed the highest consistency, whereas location and irregularity parameters showed lower consistency. The system was sensitive to changes in the intensity of the central glare source but not to pupil changes in this sample of healthy subjects.

Occupational stress and coping among portuguese military police officers

This study describes the professional experience of military police officers from the Portuguese Republican National Guard (N = 95). We focused on the main sources and consequences of stress and the coping strategies used to deal with stress. The evaluation protocol included one closed-ended question and four open-ended questions. Data analysis of meaningful text segments was conceptually based and data categorization followed deductive content analysis. Results allowed the identification of 483 meaning units. Factors intrinsic to the job and the relationships at work were the main stressors referred by participants. The consequences of stressors were evident at an individual level, affecting family, psychological, and physical/health domains. The coping strategies used to deal with the main source of stress in the professional career were focused on problem solving (e.g., active confrontation) and emotional regulation (e.g., situation acceptance). Practical implications and future avenues of research with these professionals are discussed.

The impact of carbon source in Candida albicans virulence: participation of RLM1 in pathogen host interaction

Dissertação de mestrado em Genética Molecular