2016
Authors
Barros, A; Gouvinhas, I; Machado, N; Pinto, J; Cunha, M; Rosa, E; Dominguez Perles, R;
Publication
FOOD CHEMISTRY
Abstract
A number of traditional liqueurs are obtained by maceration of red fruits in aqueous ethanol liquor, namely sloe berries or sour cherry. On the other hand, the exploration of residual plant material derived from the winery industry (grape (Vitis vinifera L.) stems), which has been regarded as an interesting source of colored and uncolored (poly)phenols, could lead to an industrial alternative to the traditional distilled spirits produced, with valuable physicochemical and phytochemical properties. In the present work, vinification residues (grape stems) were used to produce a new beverage. The evaluation of the physic-chemical characteristics and phytochemical composition as well as the evolution of the determined parameters during maceration (90 and 180 days) allowed a number of interesting bioactive compounds to be identified. This new beverage is a liqueur with a high retention of phenolic compounds (ortho-diphenols, flavanols, flavonols, and anthocyanins), with interesting physic-chemical characteristics, that revealed significant antioxidant activity.
2016
Authors
Gouvinhas, I; Machado, N; Girones Vilaplana, A; Gomes, S; Carvalho, T; Dominguez Perles, R; Barros, AIRNA;
Publication
JOURNAL OF CHEMOMETRICS
Abstract
The olive tree (Olea europaea L.) can be affected by Colletotrichum acutatum, causing a loss of yield and quality of the final products, whilst the incidence of this fungal infection depends on several factors, including cultivar susceptibility. Thus, the effect of C. acutatum infection in cultivars displaying different susceptibilities to this fungal disease (Galega Vulgar' - susceptible, Cobrancosa' - moderately susceptible, Picual' - tolerant) has been assessed through spectrophotometric methods and HPLC, while the FTIR spectra of the cuticles have been concomitantly registered, resorting to the ATR accessory. With the support of multivariate analysis, these spectra allowed to discriminate olives with distinct infection times, besides retrieving evidences concerning the different susceptibility of each cultivar, while these observations were reinforced by the spectrophotometric and chromatographic methods. Furthermore, the assessment of the phenolic profile evidenced individual compounds in the distinct cultivars, so as their variations in response to the fungal infection. Distinct olive cultivars were inoculated with Colletotrichum acutatum. The most resistant olive tree cultivars display the highest content in phenolics. FTIR-ATR-based analyses allow to monitor the response of olive fruits to C. acutatum.
2015
Authors
Kianpour, I; Hussain, B; Tavares, VG; Mendonca, HS;
Publication
2015 IEEE INTERNATIONAL SYMPOSIUM ON CIRCUITS AND SYSTEMS (ISCAS)
Abstract
This paper presents a wide input range, low-power operational transconductance amplifier (OTA) in weak inversion. The OTA is implemented with tanh-triplets differential pairs, degenerated by a composite configuration to augment the input linear range, thus reducing further the harmonic distortion. Using MATLAB, the mismatch factor (A) of a typical multi-tanh triplet has been optimised for minimum harmonic distortion. The OTA is designed in UMC 0.13um CMOS technology with 1.2V supply. Simulations show that the input range can be extended to 300 mV, while keeping the HD3 below -80 dB. The average power consumption is 13nW, with an open loop-gain of 76 dB and a unity gain frequency of 250 Hz. The low harmonic distortion OTA can find potential applications in low-power and long time constant filters.
2015
Authors
Kianpour, I; Hussain, B; Tavares, VG; Mendonca, HS;
Publication
2015 Conference on Design of Circuits and Integrated Systems (DCIS)
Abstract
An integrate-and-fire modulator (IFM) is designed for power scavenging systems like: Wireless Sensor Network (WSN) and Radio Frequency Identification (RFID) sensor tags. The circuit works with a clock in order to be able to be synchronized with microprocessors, which must be used to reconstruct the signal. The modulator is simulated using 130nm CMOS technology and the resulting power consumption is around 14nW at a clock frequency of 10 kHz. The OTA individually dissipates roughly 13nW. Signal reconstruction resulted in a 9.2 ENOB.
2015
Authors
Costa, CM; Sobreira, HM; Sousa, AJ; Veiga, G;
Publication
Cutting Edge Research in Technologies
Abstract
2015
Authors
Costa, CM; Sobreira, HM; Sousa, AJ; Veiga, GM;
Publication
2015 IEEE INTERNATIONAL CONFERENCE ON INDUSTRIAL TECHNOLOGY (ICIT)
Abstract
Autonomous robots play a pivotal role in improving productivity and reducing operational costs. They excel at both precision and speed in repetitive jobs and can cooperate with humans in complex tasks within dynamic environments. Self-localization is critical to any robot that must navigate or manipulate the environment. To solve this problem, a modular localization system suitable for mobile manipulators was developed. By using LIDAR data the proposed system is capable of achieving less than a centimeter in translation error and less than a degree in rotation error while requiring only 5 to 25 milliseconds of processing time. The system was tested in two different robot platforms at different velocities and in several cluttered and dynamic environments. It demonstrated high accuracy while performing pose tracking and high reliability when estimating the initial pose using feature matching. No artificial landmarks are required and it is able to adjust its operation rate in order to use very few hardware resources when a mobile robot is not moving.
The access to the final selection minute is only available to applicants.
Please check the confirmation e-mail of your application to obtain the access code.