2016
Autores
Godina, R; Rodrigues, EMG; Paterakis, NG; Erdinc, O; Catalao, JPS;
Publicação
ENERGY CONVERSION AND MANAGEMENT
Abstract
Widespread adoption of Electric Vehicles (EVs) could bring social and economic benefits. The effort of promoting the use of EVs in transportation is indispensable to meet the climate change related targets and to reduce the dependency on the ever unstable prices of diminishing fossil fuels. However, there are still many uncertainties in the market regarding the acceptability of EVs by the final consumers. As a new contribution with respect to earlier studies, this paper assesses the impact of EV charging load on the dielectric oil deterioration of two real Power Distribution Transformers (PDTs), one residential and one industrial, located in the insular grid of Sao Miguel. A PDT thermal model is used to estimate the hot-spot temperature given the load ratio. Real data are used for the main inputs of the model, namely, the daily residential load curve, the daily private industrial client load curve, the PDT parameters, time-of-use rates and EV parameters.
2016
Autores
Gomes, AD; Ferreira, MFS; Moura, JP; Andre, RM; Kobelke, J; Bierlich, J; Wondraczek, K; Schuster, K; Frazao, O;
Publicação
MICROWAVE AND OPTICAL TECHNOLOGY LETTERS
Abstract
A new microstructured optical fiber is presented as a sensor of acetone evaporation. Sensing is performed by observing the time response of the reflected signal at 1550 nm when the device is dipped in acetone or a 50% acetone-50% water mixture. The sensor consists on a caterpillar-like microstructured fiber spliced to a single-mode fiber, where the spliced end of the sensor has a transversal microfluidic channel etched using focused ion beam. Upon heating, different behaviors are visible between the dipping and the evaporation of acetone. The sensor is able to track the evaporation of acetone and to distinguish between pure acetone and a 50% acetone-50% water mixture. The sensor is also able to detect when the acetone in a mixture with water is fully evaporated. The detection of water vapor with no particular orientation of the sensor is achieved due to the presence of the microfluidic channels. (c) 2016 Wiley Periodicals, Inc.
2016
Autores
Rodrigues, S; Paiva, J; Pimentel, G; Silva Cunha, JPS;
Publicação
SHO2016: INTERNATIONAL SYMPOSIUM ON OCCUPATIONAL SAFETY AND HYGIENE
Abstract
Firefighting is a hazardous occupation. Firefighters are commonly subjected to high levels of stress and fatigue that could interfere with their ability to take decisions under pressure. Based on this assumption, a laboratory protocol was conducted among 10 Portuguese firefighters in order to address their stress and mental fatigue levels and its impact on cognitive performance. A 2-Choice Reaction Time Task was used to measure cognitive performance (before and after a stress condition) and a psychosocial stress paradigm was used to assess stress. Visual Analogue Scales were also used to measure perceived stress and mental fatigue. Results suggested that firefighters felt more fatigued at the end of the protocol, however their performance only decreased in the first reaction time task. Furthermore, findings suggested that stress improved firefighters reaction times, however when stress levels increased, performance decreased. This suggests the need to better understand firefighters optimal stress levels and fatigue, in order to promote their health and work safety, by improving their performance under demanding situations.
2016
Autores
Faria, JP; Paiva, ACR;
Publicação
INTERNATIONAL JOURNAL ON SOFTWARE TOOLS FOR TECHNOLOGY TRANSFER
Abstract
Novel techniques and a toolset are presented for automatically testing the conformance of software implementations against partial behavioral models constituted by a set of parameterized UML sequence diagrams, describing both external interactions with users or client applications and internal interactions between objects in the system. Test code is automatically generated from the sequence diagrams and executed on the implementation under test, and test results and coverage information are presented back visually in the model. A runtime test library handles internal interaction checking, test stubs, and user interaction testing, taking advantage of aspect-oriented programming techniques. Incremental conformance checking is achieved by first translating sequence diagrams to Extended Petri Nets that combine the characteristics of Colored Petri Nets and Event-Driven Petri Nets.
2016
Autores
Bahubalindruni, PG; Kiazadeh, A; Sacchetti, A; Martins, J; Rovisco, A; Tavares, VG; Martins, R; Fortunato, E; Barquinha, P;
Publicação
JOURNAL OF DISPLAY TECHNOLOGY
Abstract
This paper presents a study concerning the role of channel length scaling on IGZO TFT technology benchmark parameters, which are fabricated at temperatures not exceeding 180 degrees C. The parameters under investigation are unity current-gain cutoff frequency, intrinsic voltage-gain, and on-resistance of the bottom-gate IGZOTFTs. As the channel length varies from 160 to 3 mu m, the measured cutoff frequency increases from 163 kHz to 111.5 MHz, which is a superior value compared to the other competing low-temperature thin-film technologies, such as organic TFTs. On the other hand, for the same transistor dimensions, the measured intrinsic voltage-gain is changing from 165 to 5.3 and the on-resistance is decreasing from 1135.6 to 26.1 k Omega. TFTs with smaller channel length (3 mu m) have shown a highly negative turn-on voltage and hump in the subthreshold region, which can be attributed to short channel effects. The results obtained here, together with their interpretation based on device physics, provide crucial information for accurate IC design, enabling an adequate selection of device dimensions to maximize the performance of different circuit building blocks assuring the multifunctionality demanded by system-on-panel concepts.
2016
Autores
Pinheiro, AP; Barros, C; Pedrosa, J;
Publicação
SOCIAL COGNITIVE AND AFFECTIVE NEUROSCIENCE
Abstract
In a dynamically changing social environment, humans have to face the challenge of prioritizing stimuli that compete for attention. In the context of social communication, the voice is the most important sound category. However, the existing studies do not directly address whether and how the salience of an unexpected vocal change in an auditory sequence influences the orientation of attention. In this study, frequent tones were interspersed with task-relevant infrequent tones and task-irrelevant infrequent vocal sounds (neutral, happy and angry vocalizations). Eighteen healthy college students were asked to count infrequent tones. A combined event-related potential (ERP) and EEG time-frequency approach was used, with the focus on the P3 component and on the early auditory evoked gamma band response, respectively. A spatial-temporal principal component analysis was used to disentangle potentially overlapping ERP components. Although no condition differences were observed in the 210-310 ms window, larger positive responses were observed for emotional than neutral vocalizations in the 310-410 ms window. Furthermore, the phase synchronization of the early auditory evoked gamma oscillation was enhanced for happy vocalizations. These findings support the idea that the brain prioritizes the processing of emotional stimuli, by devoting more attentional resources to salient social signals even when they are not task-relevant.
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