Membrane processing of grape must for control of the alcohol content in fermented beverages

The great demand of beverages, both alcohol-free and with low alcohol content, is a great challenge for the production of beverages with controlled alcohol content through the use of sustainable enological practices. The present work addresses this challenge with the processing of grape must by reverse osmosis (RO) for must reconstitution with different sugar contents prior to the alcoholic fermentation. The original must came from grapes grown in Quinta do Quinto, in Santarém, collected after destemming and mechanic crushing, and preserved in a refrigerated chamber at -1.6 °C until processing by RO. The RO processing was carried out in Escola Superior Agrária de Santarém, with a pilot plant equipped with RO spiral wound modules, M38RO, from Alfa Laval, Denmark. The total membrane permeation area is 15 m2. The work pressure was 55 bar. The original must had 23.7 oBrix, a density of 1108 g.L-1, 15.2% (v/v) of probable alcohol, and a conductivity of 2.01 mS.cm-1. The must reconstitution was carried out, by mixing the concentrated grape must with the vegetal water produced by RO (permeate) to obtain beverages with a nominal alcohol content of 5%, 7%, 10% and 13% (v/v). The fermentation average temperature was between 18.2 and 19.7 °C, and the final density rounded about 993 g.cm-3. The beverages were analysed by different parameters, including total polyphenols, total anthocyanins, colour intensity and hue, the coordinates CIELab, alcohol content, total acidity, volatile acidity, pH, free SO2 and total SO2. The attributes of the beverage, corresponding to the visual appearance, aroma and taste senses, as well as the overall judgment were evaluated by the tasters. The proposed method can produce beverages with controlled low alcohol content. The decrease of the alcohol content led to lower content of polyphenols compounds which influenced the sensory evaluation.info:eu-repo/semantics/publishedVersio

Structuring wicked problems in transdisciplinary research using the Social-Ecological Systems framework: an application to the montado system, Alentejo, Portugal

The aspiration to establish an effective dialogue between science and society has inspired some ground breaking examples of transdisciplinarity (TD). The core idea of TD is that different academic disciplines work jointly with practitioners to solve common problems. The first step of TD implies a contextualization that requires holistic and systemic thinking. To achieve this contextualization, we applied the Social–Ecological Systems (SES) framework with the aim of developing TD to deal with the recorded decline in area and tree density of the montado land-use system located in the Alentejo region, Portugal. The study was based both on a literature review and on the analysis of qualitative and quantitative data collected in a number of research projects on the montado. The results show that the lack of consensus regarding the system boundaries, the diverse range of mental models, and the disconnection between policymaking and system singularities are some of the conditions that can hinder TD efforts. The framework allowed the identification of knowledge gaps that limit the understanding of the problem complexity to be dealt with by a TD research process. There is a need to gain a better understanding of the governance system, and to characterize the different types of agro-silvo-pastoral combinations that can be designated as montado. With this detailed understanding, a tailored TD process can be designed. This work argues for the active use of the SES framework in TD in environmental management. Future research could focus on the framework’s utility in developing tools to assess and monitor transdisciplinary research

Artificial Neural Network Symbol Estimator With Enhanced Robustness to Nonlinear Phase Noise

This letter reports a novel approach for nonlinear phase noise mitigation, based on artificial neural networks (ANNs) tailored to classification applications and a pre-processing stage of feature engineering. Starting with a set of proof-of-concept simulations, we verify that the proposed system can achieve optimal performance for the additive white Gaussian noise (AWGN) channel. Then, considering a dispersion-less channel with strong nonlinear phase noise (NLPN) distortion, we demonstrate a Q-factor increase of 0.4dB, comparing with standard carrier-phase estimation (CPE) followed by minimum distance detection. Finally, simulating the propagation of 64Gbaud PM-16QAM over standard single mode fiber (SSMF), we verify that the ANN-based solution is effective on wavelength-division multiplexing (WDM) transmission conditions, enabling to increase the maximum signal reach by approximately 1 fiber span over the legacy CPE-enabled NLPN compensation

The Interface and Control System of the Upgraded HVOpto/HVRemote Card of the TileCal

To comply with the increase in luminosity of the LHC (Large Hadron Collider) in the next decades, the electronics of the ATLAS (A Toroidal LHC Apparatus) experiment is being upgraded. Included in the upgrade is the interfacing and control electronics system of the HVOpto/HVRemote cards in the TileCal (Tile Calorimeter) detector, which provides high voltages to about 104 photomultipliers (PMTs). This paper presents the new interfacing architecture for the system and details the design of a prototype control board (HVRemote-Ctrl) used for test and validation of the new architecture. The tests evaluate the system multiplexing capabilities needed to monitor all the TileCal PMTs in real time. The communication channels involved, supported in Ethernet and SPI interfaces/protocols, have been fully tested. Some results from the tests already completed are presented

A one-phase interior point method for nonconvex optimization

The work of Wachter and Biegler suggests that infeasible-start interior point methods (IPMs) developed for linear programming cannot be adapted to nonlinear optimization without significant modification, i.e., using a two-phase or penalty method. We propose an IPM that, by careful initialization and updates of the slack variables, is guaranteed to find a first-order certificate of local infeasibility, local optimality or unboundedness of the (shifted) feasible region. Our proposed algorithm differs from other IPM methods for nonconvex programming because we reduce primal feasibility at the same rate as the barrier parameter. This gives an algorithm with more robust convergence properties and closely resembles successful algorithms from linear programming. We implement the algorithm and compare with IPOPT on a subset of CUTEst problems. Our algorithm requires a similar median number of iterations, but fails on only 9% of the problems compared with 16% for IPOPT. Experiments on infeasible variants of the CUTEst problems indicate superior performance for detecting infeasibility. The code for our implementation can be found at https://github.com/ohinder/OnePhase .Comment: fixed typo in sign of dual multiplier in KKT syste

Experimental Demonstration of a Frequency-Domain Volterra Series Nonlinear Equalizer in Polarization-Multiplexed Transmission

Experimental demonstration of a dual-polarization Volterra series nonlinear equalizer applied in frequency-domain is carried out for 100G polarization-multiplexed QPSK test signals. We were able to reduce the BER by a factor of ~2.5x relatively to the single-polarization approach, with a 1 dB increase in the optimum power

Adaptive Stokes-Based Polarization Demultiplexing for Long-Haul Multi-Subcarrier Systems

We experimentally evaluate the performance of the adaptive Stokes polarization demultiplexing (PolDemux) algorithm over a long-haul optical link considering the propagation of 31 × 192 Gb/s channels modulated as PM-16QAM multisubcarrier (MSC) signals. Initially, we consider 1 × 24 Gbaud channel under test, and subsequently, we assess the performance of the algorithm on an increasing number of subcarriers (up to 12 × 2 Gbaud) while keeping the same aggregate symbol rate. Taking advantage of the higher robustness of MSC signals toward chromatic dispersion (CD), we demonstrate that the memoryless Stokes-based PolDemux algorithm, originally designed for short reach links, can also be used for low-complexity and modulation transparent polarization demultiplexing in long-haul systems. In addition, we demonstrate that the PolDemux rotation matrix for the MSC signals can be estimated over a restricted group of Nref subcarriers and seamlessly applied to all Nsc subcarriers, thereby significantly reducing the overall complexity by a factor of ∼Nsc/Nref

Characterization and modeling of link loss for an outdoor free-space optics transmission system

In this paper we propose three low-complexity algorithms to estimate the time-varying loss of an outdoor 1550-nm free-space optics (FSO) link with 55-m transmission length. Longterm experimental measurements taken for different weather conditions demonstrate that the link loss can be predicted accurately while still using low-complexity algorithms