Control, regulation and command system of hydronic radiant floors heating by wireless and energy harvesting sensors and actuators

This paper presents the development of an innovative control, regulation and command system for hydronic radiant floors, more flexible and efficient that guarantees a better thermal comfort to the user and simultaneously improves the energy efficiency of this type of heating system. The majority of the actual control of hydronic radiant floors is done by thermostats that measure the air temperature and control the actuators (pumps and valves) in order to maintain the room at the specified temperature. These systems requires the frequent adjustment of thermostats set-point in order to obtain thermal comfort as it depends on other factors than just the air temperature, such as, the air humidity, external environmental conditions, radiant temperature, among others. This paper presents a control, regulation and command solution that requires minimum user intervention, as the user only has to choose the desirable thermal comfort level. The control algorithm is based on the calculation of PMV (Predicted Mean Vote) index as defined on Thermal Comfort Standard ISO 7730. Another advantage of the proposed system is related to the wireless and energy harvesting sensors and actuators that provide much more flexibility to the system.info:eu-repo/semantics/publishedVersio

Quark matter revisited with non extensive MIT bag model

In this work we revisit the MIT bag model to describe quark matter within both the usual Fermi-Dirac and the Tsallis statistics. We verify the effects of the non-additivity of the latter by analysing two different pictures: the first order phase transition of the QCD phase diagram and stellar matter properties. While, the QCD phase diagram is visually affected by the Tsallis statistics, the resulting effects on quark star macroscopic properties are barely noticed.Comment: 10 pagens, 5 figure

Experimental evaluation of an innovative command for hydronic radiant heating floors

This paper presents the results of an innovative control, regulation and command system for hydronic radiant floors, more flexible and efficient that guarantees a better thermal comfort to the user and simultaneously improves the energy efficiency of this type of heating system. The control algorithm is based on the calculation of PMV (Predicted Mean Vote) index as defined on Thermal Comfort Standard ISO 7730. To improve energy efficiency, the control algorithm was implemented on a microcontroller system that fea-tures wireless communication with sensors modules powered by energy harvesting systems. The experimental tests were performed in a hydraulic underfloor built into a laboratorial climatic chamber. The results show that for a water inlet of 35 ºC, the controller turn the valve on/off less than other control systems in order to adjust the PMV while maintaining the floor surface temperature less than 29 ºC as recommended by international standards.info:eu-repo/semantics/publishedVersio

Spreading gossip in social networks

We study a simple model of information propagation in social networks, where two quantities are introduced: the spread factor, which measures the average maximal fraction of neighbors of a given node that interchange information among each other, and the spreading time needed for the information to reach such fraction of nodes. When the information refers to a particular node at which both quantities are measured, the model can be taken as a model for gossip propagation. In this context, we apply the model to real empirical networks of social acquaintances and compare the underlying spreading dynamics with different types of scale-free and small-world networks. We find that the number of friendship connections strongly influences the probability of being gossiped. Finally, we discuss how the spread factor is able to be applied to other situations.Comment: 10 pages, 16 figures, Revtex; Virt.J. of Biol. Phys., Oct.1 200

Achieving enhanced peroxidase-like activity in multimetallic nanorattles

Gold nanoparticles (Au NPs) have been extensively used as artificial enzymes, but their performance is still limited. We address this challenge by focusing on multimetallic nanorattles comprising an Au core inside a bimetallic AgAu shell, separated by a void (Au@AgAu NRs). They were prepared by a galvanic replacement approach and contained an ultrathin and porous shell comprising an AgAu alloy. By investigating the peroxide-like activity using TMB oxidation as a model transformation, we have found an increase of 152 fold in activities for the NRs relative to conventional Au NPs. Based on the kinetics results, the NRs also showed the lowest K-m, indicating better interaction with the substrate and faster product formation. We also observed a linear relationship between the concentration of the product and oxTMB as a function of H2O2 concentration, which could be further applied for H2O2 sensing applications (colorimetric detection). These data suggest that the NRs enable the combined effect of an increased surface area relative to solid counterparts, the possibility of exposing highly active surface sites, and the exploitation of nanoconfinement effects due to the void regions between the core and shell components. These results provide important insights into the optimization of peroxidase-like performances beyond what can be achieved in conventional NPs and may inspire the development of better-performing artificial enzymes.Peer reviewe

Seasonal fluctuations of the airborne pollen in Guarda (Portugal)

Airborne pollen calendars are useful to estimate the flowering season of the different plants as well as to indicate the allergenic potential present in the atmosphere at a given time. In this study, a 1-year survey (from January 2013 to February 2014) is presented of the atmospheric concentration of pollen types in Guarda (Portugal), using a 7-day Hirst volumetric trap. The daily mean concentration of both the number of pollen grains and the main pollen season was determined as well as the bi-hourly variations. The highest airborne pollen concentration was found during early spring and early summer. Contrastingly, December was the month with the lowest pollen concentration. The major pollens sampled were Quercus, Pinaceae, Poaceae, Cupressaceae, Urticaceae, Apiaceae, Oleaceae and Polygonaceae. Some differences were found in the intradiurnal distribution patterns of the pollen types studied, with some taxa types being predominantly sampled in the morning (8:00-10:00 a.m.) while others were more evident in the late evening hours (8-10 p.m.). Finally, these results were compared with the forecast made by the Portuguese Aerobiology Network for the central region of Portugal, revealing some significant differences in the pollination periods

Factorial analysis of the trihalomethanes formation in water disinfection using chlorine

The factors that affect trihalomethane (THM) (chloroform, bromodichloromethane, chlorodibromomethane and bromoform) formation from the chlorination of aqueous solutions of hydrophobic fulvic acids (FA) were investigated in a prototype laboratorial simulation using factorial analysis. This strategy involved a fractional factorial design (16 plus 5 center experiments) of five factors (fulvic acids concentration, chlorine dose, temperature, pH and bromide concentration) and a Box Behnken design (12 plus 3 center experiments) for the detailed analysis of three factors (FA concentration, chlorine dose and temperature). The concentration ofTHMwas determined by headspace analysis by GC–ECD. The most significant factors that affect the four THM productions were the following: chloroform—FA concentration and temperature; bromodichloromethane—FA concentration and chlorine dose; chlorodibromomethane—chlorine dose; and, bromoform—chlorine dose and bromide concentration. Moreover, linear models were obtained for the four THM concentrations in the disinfection solution as function of the FA concentration, chlorine dose and temperature, and it was observed that the complexity of the models (number of significant factors and interactions) increased with increasing bromine atoms in the THM. Also, this study shows that reducing the FA concentration the relative amount of bromated THM increases

Plasmonic catalysis with designer nanoparticles

Catalysis is central to a more sustainable future and a circular economy. If the energy required to drive catalytic processes could be harvested directly from sunlight, the possibility of replacing contemporary processes based on terrestrial fuels by the conversion of light into chemical energy could become a step closer to reality. Plasmonic catalysis is currently at the forefront of photocatalysis, enabling one to overcome the limitations of "classical" wide bandgap semiconductors for solar-driven chemistry. Plasmonic catalysis enables the acceleration and control of a variety of molecular transformations due to the localized surface plasmon resonance (LSPR) excitation. Studies in this area have often focused on the fundamental understanding of plasmonic catalysis and the demonstration of plasmonic catalytic activities towards different reactions. In this feature article, we discuss recent contributions from our group in this field by employing plasmonic nanoparticles (NPs) with controllable features as model systems to gain insights into structure-performance relationships in plasmonic catalysis. We start by discussing the effect of size, shape, and composition in plasmonic NPs over their activities towards LSPR-mediated molecular transformations. Then, we focus on the effect of metal support interactions over activities, reaction selectivity, and reaction pathways. Next, we shift to the control over the structure in hollow NPs and nanorattles. Inspired by the findings from these model systems, we demonstrate a design-driven strategy for the development of plasmonic catalysts based on plasmonic-catalytic multicomponent NPs for two types of molecular transformations: the selective hydrogenation of phenylacetylene and the oxygen evolution reaction. Finally, future directions, challenges, and perspectives in the field of plasmonic catalysis with designer NPs are discussed. We believe that the examples and concepts presented herein may inspire work and progress in plasmonic catalysis encompassing the design of plasmonic multicomponent materials, new strategies to control reaction selectivity, and the unraveling of stability and reaction mechanisms.Peer reviewe