Cookies Policy
The website need some cookies and similar means to function. If you permit us, we will use those means to collect data on your visits for aggregated statistics to improve our service. Find out More
Accept Reject
  • Menu
Publications

2017

Inactivation of pathogenic microorganisms in freshwater using HSO5-/UV-A LED and HSO5-/Mn+/UV-A LED oxidation processes

Authors
Rodriguez Chueca, J; Silva, T; Fernandes, JR; Lucas, MS; Puma, GL; Peres, JA; Sampaio, A;

Publication
WATER RESEARCH

Abstract
Freshwater disinfection using photolytic and catalytic activation of peroxymonosulphate (PMS) through PMS/UV-A LED and PMS/Mn+/UV-A LED [Mn+ = Fe2+ or Co2+] processes was evaluated through the inactivation of three different bacteria: Escherichia coli (Gram-negative), Bacillus mycoides (sporulated Gram-positive), Staphylococcus aureus (non-sporulated Gram-positive), and the fungus Candida albicans. Photolytic and catalytic activation of PMS were effective in the total inactivation of the bacteria using 0.1 mM of PMS and Mn+ at neutral pH (6.5), with E. coli reaching the highest and the fastest inactivation yield, followed by S. aureus and B. mycoides. With B. mycoides, the oxidative stress generated through the complexity of PMS/Mn+/UV-A LED combined treatments triggered the formation of endospores. The treatment processes were also effective in the total inactivation of . albicans, although, due to the ultrastructure, biochemistry and physiology of this yeast, higher dosages of reagents (5 mM of PMS and 2.5 mM of Mn+) were required. The rate of microbial inactivation markedly increased through catalytic activation of PMS particularly during the first 60 s of treatment. Co2+ was more effective than Fe2+ to catalyse PMS decomposition to sulphate radicals for the inactivation of S. aureus and C. albicans. The inactivation of the four microorganisms was well represented by the Horn model. The Biphasic and the Double Weibull models, which are based on the existence of two microbial sub-populations exhibiting different resistance to the treatments, also fitted the experimental results of photolytic activation of PMS.

2017

Optimal Demand Response Scheme for Power Systems Including Renewable Energy Resources Considering System Reliability and Air Pollution

Authors
Ribeiro, MF; Shafie khah, M; Osorio, GJ; Hajibandeh, N; Catalao, JPS;

Publication
2017 1ST IEEE INTERNATIONAL CONFERENCE ON ENVIRONMENT AND ELECTRICAL ENGINEERING AND 2017 17TH IEEE INDUSTRIAL AND COMMERCIAL POWER SYSTEMS EUROPE (EEEIC / I&CPS EUROPE)

Abstract
Implementing an applicable demand response (DR) program enables the complete demand-side potentials and ensures a secure, more economic and greener operation of the power systems with the integration of renewable energy. Therefore, the present paper proposes a stochastic security-constraint scheduling approach for optimum operation of both supply and demand sides via well-designed pricing and incentive schemes. The DR programs are time-of-use and emergency DR programs. The study addresses the Independent System Operator (ISO)'s viewpoint, and it aims at finding the optimal DR strategy (from a set of DR programs) in a way that an efficient electricity market is obtained, ensuring the security and environmental constraints. To this end, a security constraint unit commitment (SCUC) problem considering DR and renewable energy resources is proposed. Different indices are considered through a multi-objective problem for evaluating the efficiency of the market, security of the system, reliability and air pollution. These indices include market prices, social welfare, load factor (peak-to-valley proportion), air pollution, and power security, among others. In order to find the best DR strategy, a multi-objective problem is solved to consider all the mentioned indices.

2017

Correntropy applied to fault detection in analogue circuits

Authors
Da Silva, JM;

Publication
Proceedings of the 2017 IEEE 22nd International Mixed-Signals Test Workshop, IMSTW 2017

Abstract
Efficient test and diagnosis methods are required to ensure high levels of dependability of the electronic systems deployed to the market. These methods involve a trade-off in terms of accessibility to test nodes, test stimuli complexity, area overhead, and data processing that, altogether determine the impact that the involved operations have in the final cost, performance, and reliability presented by these systems. The work presented here describes preliminary results obtained with the application of correntropy as a means to efficiently analyse test responses in the fault detection decision process. © 2017 IEEE.

2017

PROPULSION SYSTEMS MODELLING FOR MATERIALS HANDLING VEHICLES - FORKLIFTS

Authors
Moura, C; Amorim, EV;

Publication
PROCEEDINGS OF THE 3RD INTERNATIONAL CONFERENCE ON ENERGY AND ENVIRONMENT (ICEE 2017)

Abstract
In the material handling industry, productivity is a vital driver of profitability. Efficient operation of a forklift fleet is a significant factor in determining overall warehouse productivity. Traditionally, lead-acid batteries have been the best choice for forklifts operated indoors where emissions are restricted for health and safety reasons. More recently the application of fuel cells in this type of activity has emerged, also guaranteeing operational and environmental benefits (Elgowainy et al., 2009), and it is also shown as a possible solution to increase the productivity of a warehouse (Ballard, 2013). Withing the material handling industry the increased productivity comes through range extension enabling operation of the forklift with quick refuelling, without the need for battery recharging, as well as the existence of a constant power throughout the whole work cycle (Ballard, 2013). The performance of a forklift truck powered by PEM fuel cell or a lead acid battery is modelled and investigated by conducting a parametric study (Hosseinzadeh et al., 2013). In this study as a function of the number of daily trips of a forklift is characterised its energy expenditure, with the purpose of dimensioning, in an intelligent way opt for the most efficient propulsion system. Note that the two systems currently have a very different development stage, because the use of batteries is a technology implemented much more than the fuel cells. Our objective is, according to the workload that the company demands its forklifts to adapt the propulsion system that allows obtaining a greater productivity. In this model is studied several kinds of forklifts of Class I, II and III of the 1000 to 9000 kg in a wide range of loads.

2017

Structural, morphological, ionic conductivity, and thermal properties of pectin-based polymer electrolytes

Authors
Mendes, JP; Esperanca, JMSS; Medeiros, MJ; Pawlicka, A; Silva, MM;

Publication
MOLECULAR CRYSTALS AND LIQUID CRYSTALS

Abstract
New polymer electrolytes (PEs), potentially interesting for solid-state electrochemical devices applications, were synthesized by a solvent casting method using pectin and ionic liquid (IL) N,N,N-trimethyl-N-(2-hydroxyethyl)ammonium bis(trifluoromethylsulfonyl)imide ([N-1 1 1 2(OH)] [NTf2]. The resulting electrolytes besides being moderately homogenous and thermally stable below 155 degrees C, they also exhibited good mechanical properties. The SPE membranes were analyzed by differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and complex impedance spectroscopy.

2017

Validation of a low intrusiveness heart rate sensor for stress assessment

Authors
Pereira, T; Almeida, PR; Cunha, JPS; Aguiar, A;

Publication
BIOMEDICAL PHYSICS & ENGINEERING EXPRESS

Abstract
Heart rate variability (HRV) analysis has been used as a quantitative marker of the autonomous nervous system activity to measure mental stress. Wearable sensors have been emerging as a solution to collect HRV data for stress assessment in a real context, however such studies raise additional requirements. The wearable system must be minimally obtrusive to allow the subjects to perform their tasks without interference, and inconspicuous to avoid the anxiety associated with wearing medical devices in public. The purpose of this study was to quantify the accuracy trade-off in the use of a chest band heart rate sensor that is less intrusive and less costly than a wearable electrocardiogram (ECG). The HRV metrics extracted from a chest band heart rate monitor, Zephyr HxM (TM) (Zph (TM)), were compared with those extracted from an ECG certified medical device, Vital Jacket (TM) (VJ (TM)). The two systems were worn simultaneously. under laboratory conditions by a population of 14 young and healthy subjects, aged 20 to 26 years, under the stress induced by the Trier Social Stress Test (TSST) procedure. The results showed a mean difference between RR intervals of 9 ms; a. root-mean square error. (RMSE) of less than 8% and. a Pearson's correlation higher than 0.946, considering all TSST phases. In the HRV analysis, the average of all normal intervals (AVNN) showed errors less than 2% between the two systems with a correlation higher than 0.99 for all TSST phases. We thus conclude that the used chest band sensor represents an alternative to the current wearable medical devices to monitor RR intervals, and could be used for mental stress monitoring similar to the TSST protocol.

  • 2323
  • 4496