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Publicações

Publicações por CPES

2022

A systematic review of ventilation conditions and airborne particulate matter levels in urban offices

Autores
Felgueiras, F; Mourao, Z; Moreira, A; Gabriel, MF;

Publicação
INDOOR AIR

Abstract
Many working activities are carried out in office buildings that are located in urban areas. Several studies have shown that these workplaces are likely to present poor indoor environmental quality (IEQ) due to inadequate ventilation rates, compromised thermal comfort conditions, and/or high concentration of air pollutants, such as particulate matter. This study aimed to review ventilation conditions, based on carbon dioxide (CO2) concentrations, and indoor airborne particulate matter (PM2.5 and PM10) levels assessed in offices worldwide. The approach carried out in this work followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Six databases (Scopus, Web of Science, PubMed, Inspec, Science Direct, and Dimensions) were used to search for peer-reviewed articles on the subject of IEQ, in particular, those reporting data for the levels of CO2 and particulate matter in offices, published during the last decade. Firstly, 394 records were identified, resulting in 23 articles included in the review after the screening process and the implementation of eligibility criteria. Based on the results and considering the mean concentration reported, office environments present, in general, acceptable ventilation conditions (mean: 665 ppm). However, the few cases of studies that reported CO2 values exceeding 1000 ppm identified situations of high occupancy density and inadequate operation of heating, ventilation, and air conditioning (HVAC) systems as the unequivocal causative factors. In turn, PM2.5 and PM10 seemed to be IEQ parameters that are even more critical to be tackled in offices, with the reported overall mean values (36 and 63 mu g/m(3)) exceeding the current World Health Organization (WHO) guidelines (15 and 45 mu g/m(3)). The highest aerosol concentrations were typically found in naturally ventilated buildings and were mostly associated with the influence of high levels of particles introduced indoors through the outdoor air. Overall, measures for improving IEQ in offices toward promoting healthy and safe environments for workers include strategies to periodically control IEQ, ensure the adequate percentage of fresh air and maintenance of the mechanical ventilation systems (operation, maintenance, and air filtration efficiency), and adjust occupancy to the room dimensions and ventilation conditions.

2022

A systematic review of environmental intervention studies in offices with beneficial effects on workers? health, well-being and productivity

Autores
Felgueiras, F; Cunha, L; Mourao, Z; Moreira, A; Gabriel, MF;

Publicação
ATMOSPHERIC POLLUTION RESEARCH

Abstract
An increased risk of developing stress, musculoskeletal and cardiovascular diseases, rhinitis, skin and eye irri-tations and headaches has been particularly reported among office workers. Some of these complaints have been linked to the existence of poor indoor environmental quality (IEQ) in the workplaces. In this context, inter-vention studies can offer new insights to tackle poor IEQ issues and to identify effective measures to reduce IEQ-related risks. This review summarizes the main characteristics of environmental intervention studies that have been performed in office settings and the respective findings on the beneficial effects on the promotion of health, well-being, comfort, and productivity among office workers. The study design followed PRISMA guidelines and the search for peer-review articles was conducted in Scopus, Web of Science, PubMed, and Cochrane Library databases. Firstly, 513 records were identified, resulting in 23 articles included in the review after the application of the study eligibility criteria and identification of additional important works within the subject. The revised experimental studies were mainly focused on changes in ventilation systems via replacement of air filters and modifications in the rate of outdoor air supplied or temperature set-points. Some studies also included in-terventions based on the implementation of air cleaning and biophilic strategies. Both objective (e.g., physio-logical examinations) and subjective (e.g., questionnaires) measures have been used to assess the effects on office workers' outcomes. Overall, the findings presented here confirm that interventions aiming at improving IEQ in offices can be effective in improving health, well-being and productivity among office workers.

2022

ULTRA-LOW NOISE, HIGH-SENSITIVITY MEMS ACCELEROMETER FOR SATELLITE GRAVIMETRY

Autores
Garcia, S; Elhawash, M; Cabral, J; Hormigo, T; da Encarnação, T; Alves, S; Dias, A;

Publicação
2022 Solid-State Sensors, Actuators and Microsystems Workshop, Hilton Head 2022

Abstract
Satellite gravimetry requires sub-ng acceleration measurement at frequencies below 100mHz. To bring the performance of a MEMS accelerometer closer to this level, one must decrease noise sources and maximize sensitivity (to decrease input-referred electronic noise). Electrostatic pull-in based operation has great potential for high sensitivity since it relies on time transduction. Devices were fabricated with maximized proof mass (170mg over a 13x14mm2 footprint) and tuned damping coefficient (trade-off between noise and sensitivity – pull-in operation requires low Q-factors). Novel stopper designs and caps limit both in-plane and out-of-plane displacements. Devices tested using pull-in voltage-based transduction showed sensitivity of 218 V/g. © 2022 TRF.

2022

Effect of models uncertainties on the emission constrained economic dispatch. A prediction interval-based approach

Autores
Carrillo-Galvez A.; Flores-Bazán F.; Parra E.L.;

Publicação
Applied Energy

Abstract
Although electricity is a clean and relatively safe form of energy when it is used, the generation and transmission of electricity have severe effects on the environment. An alternative to diminish the polluting emissions released by the generating units is the Emission Constrained Economic Dispatch (ECED). This is an optimization problem where the total fuel cost is minimized while treating emissions as a constraint with a pre-specified limit. Usually, the fuel cost and emission functions of the generating units must be experimentally derived, introducing then uncertainties in the obtained models. However, these uncertainties are often neglected and the ECED problem is solved considering the coefficients of the functions involved as exact (totally known) values. In this investigation we analyzed the effect of the uncertainties associated to the experimental derivation of the input–output curves of thermal power plants. Particularly, when polynomial models are fitted through multiple linear regression, we proposed an approach that, based on the respectively prediction intervals, can provide solutions immunized, in some sense, against variability in the coefficients estimates. We tested the proposed approach in a real system from the Chilean electrical power network. For the analyzed system we noted that, when uncertainties are not considered, the deterministic optimal solutions can be environmentally infeasible in some scenarios; whereas solutions obtained through the proposed approach, can significantly diminish the risk of environmental violations. The robustness of the prediction interval-based solutions was obtained with a negligible increase of the total fuel cost in all the cases studied.

2022

Projeto e Simulação das Bobinas de um Sistema de Transferência de Energia Sem Fio para Aplicação na Recarga de Veículos Elétricos

Autores
Pedro Gelati Pascoal; Leonardo A. Brum Viera; Cassiano Rech; Rafael Concatto Beltrame; Vitor Cristiano Bender;

Publicação
Procedings do XXII Congresso Brasileiro de Automática - Procedings do XXIV Congresso Brasileiro de Automática

Abstract

2022

Two-Stage Stochastic Optimization Model for Multi-Microgrid Planning

Autores
Vera, EG; Canizares, CA; Pirnia, M; Guedes, TP; Melo, JD;

Publicação
IEEE Transactions on Smart Grid

Abstract

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