2,737 research outputs found
Assessing the Environmental Impact of Thermal Transmittance Tests Performed in Façades of Existing Buildings: The Case of Spain
Thermal transmittance tests constitute an appropriate tool to assess the energy performance of existing buildings. The heat flow meter method and the thermometric method are the most used experimental methods. One of the main criteria to guarantee appropriate test conditions and the representation of results is to ensure a high thermal gradient. For this purpose, heating or air conditioning systems should be used from three to seven days. Most studies related to experimental methods have addressed the appropriate test conditions; however, the environmental impact related to these conditions have not been analyzed. This study analyzes the energy consumption and the CO2 emissions related to the conditions of the thermal gradient required for tests. An energy analysis of 129,600 cases located in Spain was conducted. The results showed that heating systems are the best option to perform thermal transmittance tests, whereas air conditioning systems do not guarantee appropriate test conditions. As for the energy consumption and the percentage of hours with an appropriate thermal gradient, the adequacy of the heating setpoint temperature according to the predicted estimations of the external temperature during tests would mitigate their environmental impact. The reason is that, in certain cases, the increase of the setpoint temperature does not improve test conditions. Also, the use of heating systems would imply short test durations. Finally, the selection of small rooms with a small façade length would reduce the percentage of CO2 emissions between 31.37% and 36.1%. The results of this study could guarantee a more sustainable performance of thermal transmittance tests. In addition, the results could be used to perform life cycle analysis on buildings where thermal transmittance tests are performe
Internationalization Based on Content Modification Combined with Project Management Methodology: An Application in a Spanish Postgraduate Course in Building Engineering
Internationalizing university studies can be something of a challenge for courses related
to engineering and architecture because their content is mainly focused on the standards of the
country. In this regard, the content of the degree programmes in building engineering in Spain is
based on the Spanish Building Technical Code. For this reason, this paper analyses experimentation
conducted in a postgraduate course in building engineering of the University of Seville. The goal of
the study was to internationalize the course content of that course appropriately. For this purpose, a
combined approach was developed based on using ISO standards and including appropriately the
modifications through a project management methodology to reduce risks. Experimentation was
conducted for three academic years: 2018/2019–2020/2021. The results showed that ISO standards
were appropriately implemented in the teaching course content and accepted by students. Likewise,
the use of a project management methodology could be an opportunity to improve teaching course
content, thus reducing the risk related to the modifications of this process
Analysis of the impact of the use profile of HVAC systems established by the Spanish standard to assess residential building energy performance
State regulations play an important role to guarantee an appropriate building energy performance. As for the Spanish regulation, the limitation of energy consumption should be analyzed with simulation tools by using operational profiles. The profile of operational conditions of HVAC
systems in residential buildings limits the use of heating and cooling systems. This paper studied the limitations of the residential profile in energy assessment processes through simulation tools. A case study was analyzed with three operational approaches and was placed in 8131 Spanish cities. The results showed that the use limitations of cooling systems lead to ignorance of an important percentage contribution in the cooling energy demand in some months of the year. The use of an operational profile with an extended calendar for cooling systems for the entire year would imply a more appropriate knowledge of the building energy performance in order to know the fulfilment of
the state regulation and its correct energy classification
Adaptive comfort control implemented model (ACCIM) for energy consumption predictions in dwellings under current and future climate conditions: A case study located in Spain
Currently, the knowledge of energy consumption in buildings of new and existing dwellings is essential to control and propose energy conservation measures. Most of the predictions of energy consumption in buildings are based on fixed values related to the internal thermal ambient and pre-established operation hypotheses, which do not reflect the dynamic use of buildings and users’ requirements. Spain is a clear example of such a situation. This study suggests the use of an adaptive thermal comfort model as a predictive method of energy consumption in the internal thermal ambient, as well as several operation hypotheses, and both conditions are combined in a simulation model: the Adaptive Comfort Control Implemented Model (ACCIM). The behavior of ACCIM is studied in a representative case of the residential building stock, which is located in three climate zones with different characteristics (warm, cold, and mild climates). The analyses were conducted both in current and future scenarios with the aim of knowing the advantages and limitations in each climate zone. The results show that the average consumption of the current, 2050, and 2080 scenarios decreased between 23% and 46% in warm climates, between 19% and 25% in mild climates, and between 10% and 29% in cold climates by using such a predictive method. It is also shown that this method is more resilient to climate change than the current standard. This research can be a starting point to understand users’ climate adaptation to predict energy consumption
PART: Pre-trained Authorship Representation Transformer
Authors writing documents imprint identifying information within their texts:
vocabulary, registry, punctuation, misspellings, or even emoji usage. Finding
these details is very relevant to profile authors, relating back to their
gender, occupation, age, and so on. But most importantly, repeating writing
patterns can help attributing authorship to a text. Previous works use
hand-crafted features or classification tasks to train their authorship models,
leading to poor performance on out-of-domain authors. A better approach to this
task is to learn stylometric representations, but this by itself is an open
research challenge. In this paper, we propose PART: a contrastively trained
model fit to learn \textbf{authorship embeddings} instead of semantics. By
comparing pairs of documents written by the same author, we are able to
determine the proprietary of a text by evaluating the cosine similarity of the
evaluated documents, a zero-shot generalization to authorship identification.
To this end, a pre-trained Transformer with an LSTM head is trained with the
contrastive training method. We train our model on a diverse set of authors,
from literature, anonymous blog posters and corporate emails; a heterogeneous
set with distinct and identifiable writing styles. The model is evaluated on
these datasets, achieving zero-shot 72.39\% and 86.73\% accuracy and top-5
accuracy respectively on the joint evaluation dataset when determining
authorship from a set of 250 different authors. We qualitatively assess the
representations with different data visualizations on the available datasets,
profiling features such as book types, gender, age, or occupation of the
author
Design Optimization of the Aeronautical Sheet Hydroforming Process Using the Taguchi Method
The aluminium alloy sheet forming processes forging in rubber pad and diaphragm presses
(also known as hydroforming processes) are simple and economical processes adapted to aeronautical
production. Typical defects of these processes are elastic recovery, necking, and wrinkling, and they
present di culties in control mainly due to property variations of the sheet material that take place
during the process. In order to make these processes robust and unresponsive to material variations,
a multiobjective optimization methodology based on the Taguchi method is proposed in the present
study. The design of experiments and process simulation are combined in the methodology, using the
nonlinear finite element method. The properties of sheet material are considered noise factors of the
hydroforming process, the objective being to find a combination of the control factors that causes
minimal defects to noise factors. The methodology was applied to an AA2024-T3 aluminium alloy
sheet of 1 mm thickness stamping process in a diaphragm press. The results allowed us to establish
the optimal pressure values, friction coeficient between sheet and block, and friction coeficient
between sheet and rubber to reduce the elastic recovery variations and the minimal thickness before
noise facts
Estimating adaptive setpoint temperatures using weather stations
Reducing both the energy consumption and CO 2 emissions of buildings is nowadays one of the main objectives of society. The use of heating and cooling equipment is among the main causes of energy consumption. Therefore, reducing their consumption guarantees such a goal. In this context, the use of adaptive setpoint temperatures allows such energy consumption to be significantly decreased. However, having reliable data from an external temperature probe is not always possible due to various factors. This research studies the estimation of such temperatures without using external temperature probes. For this purpose, a methodology which consists of collecting data from 10 weather stations of Galicia is carried out, and prediction models (multivariable linear regression (MLR) and multilayer perceptron (MLP)) are applied based on two approaches: (1) using both the setpoint temperature and the mean daily external temperature from the previous day; and (2) using the mean daily external temperature from the previous 7 days. Both prediction models provide adequate performances for approach 1, obtaining accurate results between 1 month (MLR) and 5 months (MLP). However, for approach 2, only the MLP obtained accurate results from the 6th month. This research ensures the continuity of using adaptive setpoint temperatures even in case of possible measurement errors or failures of the external temperature probes.Spanish Ministry of Science, Innovation and Universities 00064742/ITC-20133094Spanish Ministry of Economy, Industry and Competitiveness BIA 2017-85657-
Influencia en el rendimiento energético en edificios históricos provocado por el entorno urbano y las modificaciones de proyecto: el caso de la Casa Duclós
Los edificios históricos constituyen parte fundamental del patrimonio cultural tangible de la sociedad actual. El cumplimiento de las exigencias de ahorro energético para mitigar el cambio climático, sin embargo, puede verse limitado aquà debido a las caracterÃsticas propias de estos edificios. Además, en el caso de las construcciones históricas, los principios de diseño bioclimático aplicados por los arquitectos, desde principios del siglo XX hasta la actualidad, pueden haber perdido efectividad. Ello ocurre, a veces, por las modificaciones en proyecto o por efectos del desarrollo urbanÃstico. En este estudio se analizan estos dos aspectos en un determinado edificio histórico ubicado en Sevilla: la Casa Duclós de José Luis Sert. Este presenta modificaciones en la cubierta, cuando se compara la proyectada y la construida. Asimismo, su entorno urbano se ha transformado desde que la Casa fue edificada. Para el análisis expuesto en este artÃculo, se realizaron simulaciones energéticas utilizando datos climáticos correspondientes al periodo 2000-2019. Los resultados muestran la influencia que tuvieron las modificaciones de la cubierta proyectada y la expansión urbanÃstica en el rendimiento energético del edificio, con respecto a la concepción original del inmueble.Historic buildings are a fundamental part of the tangible cultural heritage of today's society. However, complying with energy saving requirements to mitigate climate change may have limitations caused by the characteristics of these buildings. Also, in the case of historical buildings from the early 20th century to the present, bioclimatic design principles applied by architects may have lost their effectiveness. This occurs, sometimes, because of project modifications or due to the effects of urban expansion. In this study, these two aspects are analyzed in a case of a given historic building located in Seville: The Duclós House by José Luis Sert. This building has modifications on the roof, when comparing its projected and built version. Likewise, its urban environment has changed since it was built. For the analysis presented in this article, energy simulations were carried out using weather data from 2000 to 2019. The results show the influence that the modifications of the projected roof and the urban expansion had on the energy performance of the building compared to the original conception of the property
Legacy and emergent persistent organic pollutants (POPs) in NW Mediterranean deep-sea organisms
9 páginas, 4 figuras, 4 tablasThe levels and profiles of organochlorine (OC) contaminants, including polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethanes (DDTs), hexachlorocyclohexanes (HCHs) and penta- (PeCB) and hexachlorobenzene (HCB), as well as polybrominated diphenyl ethers (PBDEs) were determined in muscle samples of the deep-sea fish Alepocephalus rostratus, Coelorinchus mediterraneus and Lepidion lepidion and the red-shrimp Aristeus antennatus from the NW Mediterranean Sea. Mean PCB and DDT levels ranged from the highest concentrations in the fish A. rostratus (Σ7PCBs 6.93 ± 0.71 ng/g w.w. and ΣDDTs 8.43 ± 1.10 ng/g w.w.) to the lowest concentrations in the crustacean A. antennatus (Σ7PCBs 1.17 ± 0.24 ng/g w.w. and ΣDDTs 2.53 ± 0.26 ng/g w.w.). The concentrations of ΣHCHs and HCB were more than one order of magnitude lower, ranging from 0.07–0.36 ng/g w.w. and 0.03–0.15 ng/g w.w., respectively, while PeCB was only detected in a few samples. PBDE levels were approximately ten times lower than PCB and DDT concentrations, ranging from 0.47 ± 0.20 ng/g w.w. in A. antennatus to 0.92 ± 0.13 ng/g w.w. in A. rostratus. The high-molecular-weight PCBs 153, 138 and 180 represented 69–79% of Σ7PCBs in fish and 60% in the red shrimp. Moreover, in fish, the main DDT compound detected was the metabolite p,p′-DDE (70–80% of ΣDDTs), indicative of old DDT residues. In contrast, o,p′-DDE was the main DDT metabolite (49% of ΣDDTs) in shrimp, while the parent compound p,p′-DDT and its metabolite p,p′-DDE exhibited similar proportions of 16% and 21%, respectively. For PBDEs, the most abundant congeners were BDEs 28, 47, 99, 100 and 154 in fish (> 70% Σ14PBDEs), while BDEs 153 and 209 were also important in A. antennatus, suggesting different uptake and/or biotransformation rates of PBDEs between fish and crustacea. In this sense, the ratios BDE 99/100, BDE 153/154, and BDE 47/99 were determined as proxies for BDE metabolization capacities and contrasted among speciesThe present studywas funded by the Spanish Science and Technology Ministry projects PROMETEO (CTM2007-66316-C02-02/MAR), BIOFUN
(CTM2007-28739-E/MAR) and HERMIONE (EC-FP7 contract number 226354). Samuel Koenig holds a PhD grant (AFR 08/067) from the Fonds National de la Recherche (FNR), Luxembourg. The authors wish to thank the DeepMed Research Group (ICM-CSIC) and the R/V Garcia
del Cid (CSIC) crew for helping with sampling and I. Fernández, R. Chaler, D. Fanjul, and M. Comesaña for their technical assistance in GC and GC–MS instrumental analysisPeer reviewe
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