1,297 research outputs found
Monitoring and analytics to measure heat resilience of buildings and support retrofitting by passive cooling
Designing buildings to prevent indoor overheating requires the definition of accurate procedures
to measure the passive survivability of buildings and support retrofitting. This research proposes
innovative diagnostic methods to audit the heat resilience of buildings using long-term monitoring
data of temperature and CO2 concentrations. The aim is to identify optimal passive cooling
alternatives to retrofit the built environment through a speedy and less-disruptive assessment of
the actual building performance. The approach focuses on three steps: (1) characterisation of the
overheating situation of the indoor environment by a novel seasonal building overheating index
(SBOI) ranging from 0 to 100%; (2) diagnosis of the indoor environment through a heat balance
map that divides building performance into four thermal stages related to the positive or negative
influence of total heat flux, and the ventilation and infiltration load; (3) and calculation of air
change rates associated with ventilation and infiltration per thermal stage using the CO2-based
decay method. The diagnostic analytics were developed in Python and tested on three homes. The
results demonstrate how the proposed approach can efficiently characterise the overheating situation
of buildings, with Home 2 showing the most vulnerable scenario (SBOI>35%). Moreover,
the indicators identified the best available passive cooling opportunities concerning the reduction
of solar and heat gains for Home 2, and the increase of ventilative cooling for Home 1. The
research highlights the role of diagnostic analytics using real monitoring data to audit seasonal
building performance beyond standard tests and simulations. The source code can be found at
https://github.com/lizanafj/analytics-to-assess-the-heat-resilience-of-buildings.ERDF for the Andalusian region
US -15547Andalusian Government US.20-06European Commission 101023241Andalusian Government (Junta de Andalucia-Consejeria de Economia, Innovacion y Ciencia) POST- DOC_21-00575Spanish Governmen
Suport conductual positiu: Prevenció i detecció dels trastorns de conducta en l'àmbit escolar
Curs 2014-2015Premi Vicenç Fisas i Comella que atorguen la Fundació La Farga i la UVic al millor treball de Final de Grau (edició 2015)L’estudi d’aquesta investigació es basa en l’anàlisi dels trastorns de conducta que pot presentar l’alumnat a les escoles, concretament en la seva prevenció i detecció, per aconseguir disminuir la seva presència a les aules.
La part de la prevenció ve donada pel Suport Conductual Positiu (SCP), sistema que té com a objectiu prevenir els problemes conductuals i la detecció es realitza a partir de la utilització d’eines formals que permeten visualitzar la convivència a l’aula amb la finalitat d’aconseguir una visió més íntegra i global.
L’actuació vers les conductes problemàtiques s’ha convertit en un dels objectius més importants a l’educació. Per poder ajudar en aquest repte, es vol aportar al professorat metodologies i tècniques que facilitin la tasca d’identificació i intervenció preventiva.The study of this research is based on the analysis of behavioral disorders that can present students in schools, particularly in the prevention and detection, in order to reduce their presence in the classroom.
An important part of prevention is done by Positive Behavioral Support (PBS), a system that aims to prevent behavioral problems and detection is made from the use of formal tools that allow to visualize living in the classroom with the aim of achieving a more complete and comprehensive approach.
The action toward problem behavior has become an important education goal. To assist in this challenge, we want to provide teachers with the methodologies and techniques that facilitate the identification task and preventive intervention
Simultaneous determination of traces of PT, PD, OS, IR, RH, AG and AU by using magnetic nanoparticles solid phase extraction coupled with ICP OES
The direct analysis of these target analytes is very limited being essential sample pre-treatment techniques and the use of very sensitive instrumental techniques to carry out determinations. The inductively coupled plasma optical emission spectrometry shows a poor sensitivity because the concentration of some elements in environmental samples is below the detection limit of ICP OES. To solve this problem, preconcentration separation procedures have been proposed, minimizing the spectral and matrix interferences. Thus, enrichment is a very important issue for achievement of low detection limits [1-4].
In this study, a chelating resin 1,5 bis (di 2 pyridil) methylene thiocarbonohydrazide bonded to iron oxide magnetic nanoparticles (DPTH-MNPs) were synthesized. These magnetic nanoparticles were employed as a solid phase extraction (SPE) adsorbent for the separation and concentration of trace amounts of 7 elements (Au, Ag, Pd, Pt, Ir, Rh and Os) from environmental water samples. The main aim of this work was to develop a precise and accurate method for the simultaneous determination of the maximum possible number of elements by using this new absorbent and a multimode sample introduction system (MSIS). The MSIS acts as a system for the generation, separation and introduction of chemical vapours (CVG) and also as an introduction system for sample aerosols, in a simultaneous form, into an inductively coupled plasma-optical emission spectrometer. The on-line SPE-CVG-ICP-OES system developed was applied in the determination of the aforementioned metals in natural water samples (sea water, estuarine, lake and river water), with the least demanding and simple sample preparation procedure. The developed method was validated by analysing natural water certified reference materials (TMDA 54.4 fortified lake waters and SRM 1643e, trace elements in water; and National Institute of Standards and Technology (NIST), NIST-2557 autocatalyst). Sea water, tap water and well water samples collected from Malaga (Spain) were also analysed. The procedure has been demonstrated to be fast, easy, automatic, selective and economical, and the sensitivity was good.
The main advantage of DPTH-MNPs is its very good stability and resistance because chemisorption of chelating molecules on the surface of solid supports provides immobility, mechanical stability and insolubility. The precision (RSD), accuracy (by standard addition or recovery) and limit of detection (LOD) were used to evaluate the characteristics of the procedure. Furthermore, the proposed method was applied in the simultaneous determination of the 7 elements mentioned above with a sample throughput of about 13 h-1, thereby, reducing the time of analysis and the volume of reagents and sample required.
References [1] M. Tuzen, M. Soylak, D. Citak, H.S. Ferreira, M.G.A. Korn, M.A. Bezerra, A pre-concentration system for determination of copper and nickel in water and food samples employing flame atomic absorption spectrometry, Journal of Haz-ardous Materials 162 (2009) 1041–1045.
[2] Y. Cui, X. Chang, Y. Zhai, X. Zhu, H. Zheng, N. Lian, ICP-AES determination of trace elements after preconcentrated with p-dimethylaminobenzaldehyde-modified nanometer SiO2 from sample solution, Microchem. J. 83 (2006) 35–41.
[3] P. Liang, B. Hu, Z. Jiang, Y. Qin, T. Peng, Nanometer-sized titanium dioxide micro-column on-line preconcentration of La, Y, Yb, Eu, Dy and their determination by inductively coupled plasma atomic emission spectrometry, J. Anal. Atom. Spectrom. 16 (2001) 863–866.
[4] B. Feist, B. Mikula, K. Pytlakowska, B. Puzio, F. Buhl, Determination of heavy metals by ICP-OES and F-AAS after preconcentration with 2,2-bipyridyl and erythrosine, J. Hazard. Mater. 152 (2008) 1122–1129.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Raising the Efficiency Limit of the GaAs-based Intermediate Band Solar Cell Through the Implementation of a Mololithic Tandem with an AlGaAs top Cell.
The high efficiency limit of the intermediate band solar cell (IBSC) corresponds to the case of using as intermediate band (IB) host material a semiconductor with gap in the range of 2 eV. Traditional photovoltaic materials, such as Si and GaAs, are not appropriate to produce IB devices because their gaps are too narrow. To overcome this problem, we propose the implementation of a multi-junction device consisting of an IBSC combined with a single gap cell. We calculate the efficiency limits using the detailed balance model and conclude that they are very high (> 60% under maximum concentration) for any fundamental bandgap from 0.7 to 3.6 eV in the IBSC inserted in the tandem. In particular, the two-terminal tandem of a GaAs-based IBSC current matched to an optimized AlGaAs top cell has an efficiency limit as high as 64%
Radiative thermal escape in intermediate band solar cells
To achieve high efficiency, the intermediate band (IB) solar cell must generate photocurrent from sub-bandgap photons at a voltage higher than that of a single contributing sub-bandgap photon. To achieve the latter, it is necessary that the IB levels be properly isolated from the valence and conduction bands. We prove that this is not the case for IB cells formed with the confined levels of InAs quantum dots (QDs) in GaAs grown so far due to the strong density of internal thermal photons at the transition energies involved. To counteract this, the QD must be smaller
Sequential determination of traces of As, Sb and hg by on-line magnetic solid phase extraction coupled with Hr-Cs-Cvg-Gfaas
A green and rapid method was developed for the simultaneous separation/preconcentration and sequential monitoring pf arsenic, antimony and mercury by flow injection magnetic solid phase extraction coupled with on-line chemical vapor generation and determination by high resolution continuum source graphite furnace atomic absorption spectrometry. The system is based on chelating/cationic retention of the analytes onto a magnet based reactor designed to contain functionalized magnetic nanoparticles (MNPs). The MNP score allows overcoming the back-pressure problems that usually happen in SPME methods with NPs thanks to the possibility of inmobilizing the MNPs by applying an external magnetic field. Several chemical and flow variables were considered as factors in the optimization process using central composite designs. With the optimized procedure the detection limits obtained were 0.2, 0.003 and 0.4 µg/L for As, Sb and Hg respectively. For the quality control of the analytical performance and the validation of the developed method the analysis of two certified samples TM 24.3 and TMDA 54.4 Fortified Lake Waters was addressed. The results showed good agreement with the certified values.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Rapid Magnetic Dispersive solid phase extraction to preconcentration/determination of Cd and Pb in aqueous samples
A new magnetic dispersive solid phase extraction (MDSPE) method and graphite furnace atomic absorption spectrometry (GFAAS) have been combined for the analysis of Cd and Pb in environmental samples. For the preconcentration, a shell structured Fe3O4@graphene oxide nanospheres was synthetized and characterized. The material was suspended in the ionic liquid 1-n-butyl-3-metilimidazolium tetrafluoroborate [BMIM][BF4], the obtained stable colloidal suspension is named ferrofluid. GO presents excellent adsorbent properties for organic species due to the presence of the electronic π system. For this reason, the organic ligand [1,5-bis-(2-dipyridyl) methylene] thiocarbonohydrazide (DPTH) was used in order to form organic complexes of Cd and Pb. Once the DPTH ligand has been added to sample, the ferrofluid was injected and finely dispersed in the sample solution in order to extract the formed chelates. The complete adsorption of the chelates took place within few seconds then, the solid was separated from the solution with the aid of a strong magnet. Cd and Pb ions were desorbed from the material with 1 mL of acid nitric 5% solution and quantified by GFAAS. All experimental and instrumental variables were optimized.
The analytical performances of the optimized method were: EF (Enrichment factor): 200 with LODs (detection limit): 0.005 and 0.004 µg L-1 and LOQs (determination limit): 0.017 and 0.013 µg L-1, for Cd and Pb, respectively. The reliability of the developed procedure was tested by relative standard deviation (% RSD), which was found to be < 5%. The accuracy of the proposed method was verified using certified reference materials (SLRS-5, SPS-SW2, and BCR-723) and by determining the analyte content in spiked aqueous samples. Sea waters and tap water samples collected from Málaga (Spain) were also analysed. The determined values were in good agreement with the certified values and the recoveries for the spiked samples were around 100% in all cases.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec
Cold vapour generation electrothermal atomic absorption spectrometry and solid phase extraction based on a new nanosorbent for sensitive HG determination in environmental samples (sea water and river water)
Reunión bianual del Grupo Regional Andaluz de la Sociedad Española de Química AnalíticaMercury is not an essential element for plant or animal life and it is a potential
environmental toxic because of its tendency to form covalent bonds with organic
molecules and the high stability of the Hg-C bond. Reports estimate a total mercury
concentration in natural waters ranging from 0.2 to 100 ng L-1. Due to this fact, highly
sensitive methods are required for direct determination of such extremely low levels. In
this work, a rapid and simple method was developed for separation and preconcentration
of mercury by flow injection solid phase extraction coupled with on-line
chemical vapour generation electrothermal atomic absorption spectrometry. The
system is based on chelating retention of the analyte onto the mini column filled with a
mesoporous silica functionalized with 1,5 bis (di-2-pyridyl) methylene
thiocarbohydrazide. The main aim of this work was to develop a precise and accurate
method for the determination of the Hg. Under the optima conditions and 120 s
preconcentration time, the detection limit obtained was 0.009 μg L-1, with RSDs 3.7 %
for 0.2 μg L-1, 4.8 % for 1 μg L-1 and enrichment factor 4, Furthermore, the method
proposed has permitted the determination of Hg with a reduction in the analysis time,
the sample throughput was about 18 h-1, low consumption of reagents and sample
volume.
The method was applied to the determination of Hg in sea water and river water. For
the quality control of the analytical performance and the validation of the newly
developed method, the analysis of two certified samples, TMDA 54.4 Fortified Lake,
and LGC6187 River sediment was addressed. The results showed good agreement
with the certified values.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Magnetic dispersive solid phase microextraction coupled with on-line chemical vapor generation method to extraction/preconcentration of mercury from environmental samples and determination by graphite furnace atomic absorption spectrometry.
Mercury (Hg) is classified as priority hazardous substances. Concentrations found in the aquatic environment are at trace levels as result of natural processes, such as erosion and volcanism, and anthropogenic discharges related mainly to industrial and mining activities. Mercury is one of the most potent neurotoxins known, showing a high number of adverse health effects in animals and humans.
For this reason, a simple and rapid method for the determination and preconcentration of mercury in environmental waters is proposed. This work is based on magnetic dispersive solid phase microextraction (MDSPME) coupled with on-line chemical vapour generation (CVG). Graphite furnace atomic absorption spectrometry (GFAAS) was employed for the quantification of Hg. In the preconcentration step, a shell structured Fe3O4@graphene oxide was suspended in the ionic liquid carrier (1-n-butyl-3-metilimidazolium tetrafluoroborate [BMIM][BF4]), obtaining a stable colloidal suspension called ferrofluid. This sorbent possesses as large contact surface area and a high density of polar groups on its surface. The nanoparticles, when finely dispersed in the sample solution, result in almost complete extraction of Hg within a few seconds. All experimental and instrumental variables were optimized and the method was adequately validated by the analysis of certified reference materials of environmental waters.
Acknowledgements
The authors would like to thank Plan Propio “Proyecto Puente” de la Universidad de Málaga for financial support of this work.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec
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