bluuebunny/crossref_metadata_2025 huggingface dataset:
Reactor Pulse Operation for Nuclear Instrumentation Detector Testing – Preparation of a Dedicated Experimental Campaign at the JSI TRIGA Reactor
Authors: Radulović Vladimir , Barbot Loïc , De Izarra Grégoire , Peric Julijan , Lengar Igor
Published: November 2021

The availability of neutron fields with a high neutron flux, suitable for irradiation testing of nuclear instrumentation detectors relevant for applications in nuclear facilities such as material testing reactors (MTRs), nuclear power reactors and future fusion reactors is becoming increasingly limited. Over the last several years there has been increased interest in the experimental capabilities of the 250 kW Jožef Stefan Institute (JSI) TRIGA research reactor for such applications, however, the maximal achievable neutron flux in steady-state operation mode falls short of MTR-relevant conditions. The JSI TRIGA reactor can also operate in pulse mode, with a maximal achievable peak power of approximately 1 GW, for a duration of a few ms. A collaboration project between the JSI and the French Atomic and Alternative Energy Commission (CEA) was initiated to investigate absolute neutron flux measurements at very high neutron flux levels in reactor pulse operation. Such measurements will be made possible by special CEA-developed miniature fission chambers and modern data acquisition systems, supported by the JSI TRIGA instrumentation and activation dosimetry. Additionally, measurements of the intensity of Cherenkov light are proposed and being investigated as an alternative experimental method. This paper presents the preparatory activities for an exhaustive experimental campaign, which were carried out in 2019-2020, consisting of test measurements with not fully appropriate fission chambers, activation dosimetry and silicon photomultipliers (SiPMs) The presented results provide useful and promising experimental indications relevant for the design of the experimental campaign.
Design of a 150-miniature detectors 3D core-mapping system for the CROCUS reactor
Authors: Vitullo Fanny , Lamirand Vincent , Ambrožič Klemen , Braun Laurent , Godat Daniel , Frajtag Pavel , Pautz Andreas
Published: November 2021

The present article provides an overview of the design of a three-dimensional (3D) full-core mapping system for the CROCUS reactor, operated at the École polytechnique fédérale de Lausanne (EPFL), Switzerland. The system is composed of 149 miniature neutron detectors distributed within the core double lattice at three main axial levels. The miniature detector technology is based on the optimization of the well-proven coupling of a miniature ZnS:6LiF(Ag) scintillator to a state-of-the-art silicon photomultiplier (SiPM) via jacketed optical fibers. The challenges in the mechanical design, the detector optimization, the core criticality, and the development of the acquisition electronics are strongly interconnected and their combination is addressed in this article. The 3D full-core mapping system is foreseen to be installed in CROCUS in autumn 2021 and it will pave the way for the investigation of 3D dynamic phenomena in nuclear reactor cores.
µRANIA-V: an innovative solution for neutron detection in homeland security
Authors: Farinelli R. , Balossino I. , Bencivenni G. , Cibinetto G. , Felici G. , Fiore S. , Garzia I. , Gatta M. , Giovannetti M. , Hall-Wilton R. , Lai C. C. , Lavezzi L. , Mezzadri G. , Morello G. , Paoletti E. , Papalino G. , Pietropaolo A. , Pillon M. , Poli Lener M. , Robinson L. , Scodeggio M. , Svensson P.O.
Published: November 2021

Detection of neutrons is becoming of the utmost importance, especially in the studies of radioactive waste and in homeland security applications. The crisis of3He availability has required the development of innovative techniques. One solution is to develop light gas detectors for neutron counting to be used as portals for ports and airports. The neutron is converted on the Boron-coated cathode, releasing a charged particle, whose passage can be identified by the gas detector. While several technologies have been deployed in the past, the project μRANIA-V (μRwell Advanced Neutron Identification Apparatus) aims to detect thermal neutrons by means of the μRwell technology, an innovative gas detector. The goal is to produce tiles to operate as portals in homeland security or for radioactive waste management. The technological transfer towards the industry has started, thus the production can be cost-effective also owing to a construction process relatively easier compared to similar apparatus. By reading directly the signals from the amplification stage, the neutrons can be counted with simplified electronics further reducing the total cost. In this paper, the project will be described, with details on the μRwell technology and on the neutron counting, on the test beam performed, and on the future plans.
A comparison of bounding approach with isotopic correction factors and Monte Carlo sampling in burnup credit method
Authors: Haroková Pavlína , Lovecký Martin
Published: November 2021

One of the methodologies used in criticality safety analysis is burnup credit method, which allows considering fuel burnup in models with spent fuel. This removes excessive conservatism from the analysis, but it also brings new uncertainties originating from computational prediction of spent fuel composition. The burnup credit method offer several possibilities of how to deal with this problem, e.g. using bounding approach with correction factors on nuclide concentrations, which is simple, but still very conservative approach. Another option is Monte Carlo sampling, which aims at receiving the most realistic result as possible, but is very computationally demanding. In this work, we have analyzed correction factors for selected nuclides and compared the results of both methods on model of spent fuel storage pool. The results show how much conservative the bounding approach is – in this case, the multiplication factor was higher by almost 0.03 than in Monte Carlo sampling, exceeding the standard deviation by more than 5.4 times.
Radionuclides Contamination in Soil: Effects, Sources and Spatial Distribution
Authors: Olagbaju Peter Oluwadamilare , Wojuola Olanrewaju Bola , Tshivhase Victor
Published: November 2021

Radionuclide concentrations in the soil depend on the geological and anthropogenic activities of an area. They influence level of gamma radiation in the environment, which can cause significant health risk in humans. Due to the non-uniform distribution of radionuclides in the soil, various measurement methods have been adopted to monitor our environment. The challenges involved in collecting environmental samples, duration, technicality and cost of measurement have led to various models for predicting unmeasured locations. This article presents geostatistical method using kriging techniques, which adopt the theory of regionalized variables, to characterize the spatial distribution of radionuclide in un-sampled locations using data obtained from sampled locations. Among other things, this paper presents results of application of this method to a study area. Spatial distribution of radionuclides reveal the non-uniform distribution in the study area. Though the radionuclides level in the study area are below global average set by United Nations Scientific Committee on the Effects of atomic Radiation (UNSCEAR), the spatial distribution map can be used to provide adequate information needed by regulatory authorities in identifying the contaminated area in need of remediation.
Development of Active-Learning Units in Nuclear Engineering
Authors: Egarievwe Stephen U.
Published: November 2021

Active learning engages students in activities that could enhance their ability to analyze, synthesize, and evaluate the material being learned. Evidence-based studies have shown that active learning increases student performance in Science, Technology, Engineering, and Mathematics (STEM) courses. This paper presents the design of active learning units in nuclear engineering. The goal is to enhance students learning and technical skills, thereby improving their preparation for success in pursuing STEM graduate programs and careers in nuclear engineering. Three modes of active learning that are of interest are problem-solving, lab-based hands-on activities, and simulation. The active learning units are aimed at using interactive mode to provide students with the mastering of fundamental principles and concepts, and better understanding of how equations translate and apply to real-life engineering situations. The introductory nuclear engineering topics to be covered include radioactivity and half-life, binding energy, atom density, radiation interactions, radiation dose, radiation shielding, stopping power, and fission. An assessment plan for the effectiveness of the active-learnings units is also presented.
High efficiency perovskite solar cells using DC sputtered compact TiO2 electron transport layer
Authors: Hayali Ahmed , Alkaisi Maan M.
Published: November 2021

High conductivity and transparency of the electron-transporting layer (ETL) is essential to achieve high efficiency perovskite solar cells (PvSCs). Generally, titanium dioxide (TiO2) has been extensively utilized as an ETL in PvSCs. Both surface roughness and uniformity of the compact-TiO2 (C-TiO2) can influence the efficiency of the PvSC. This work investigates the optimization of the direct current (DC) sputtering power and the ratio of argon (Ar) to oxygen (O2) plasma to achieve high quality ETL films. The effect of changing the DC sputtering power on the C-TiO2 films and subsequently on the overall efficiency was studied. The electrical and optical properties of the C-TiO2 layer were characterized for various DC powers and different ratios of Ar to O2 plasma. It was found that the optimum preparation conditions for the C-TiO2 films were obtained when the DC power was set at 200 W and a flow rate of 6 sccm Ar and 12 sccm O2. A power conversion efficiency (PCE) of 15.3% in forward sweep and 16.7% in reverse sweep were achieved under sunlight simulator of 100 mW/cm2. These results indicate that significant improvement in the efficiency can be achieved, by optimizing the C-TiO2 layer.
Similar stress repartition for a standard uncemented collared femoral stem versus a shortened collared femoral stem
Authors: Batailler Cécile , Shatrov Jobe , Schmidt Axel , Servien Elvire , Puch Jean Marc , Lustig Sébastien
Published: November 2021

Introduction: The design of uncemented femoral stems for use in total hip arthroplasty has evolved. Several uncemented short stems have been developed with different bone fixations, shapes, or stem lengths. The literature analyzing the biomechanical performance of short to standard stem lengths is limited. The aim was to compare the stress repartition on a standard uncemented stem and a shortened uncemented femoral stem with the same design features. Material and methods: This finite element analysis assessed the stress repartition on two femoral components with the same design (uncemented, collared, proximal trapezoidal cross-section, and a tapered quadrangular distal stem) but with two different lengths. The shortened stem was shorter by 40 mm compared to the standard stem. The stress repartition was analysed according to the Von Mises criterion. Results: The stress repartition was similar for the standard and shorter stem without significant difference (p = 0.94). The mean Von Mises stress was 58.1 MPa [0.2; 154.1] for the standard stem and 57.2 MPa [0.03; 160.2] for the short stem. The distal part of the standard stem, which was removed in the short stem, had mean stress of 3.7 MPa [0.2; 7.0]. Conclusion: The finite element analysis found similar stress repartitions between a standard uncemented collared stem and a short, collared stem with the same design. A clinical study assessing the clinical outcomes and the bone remodelling with a collared short stem would be interesting to confirm these first promising results.
Diagnostik und Therapie des Pankreaskarzinoms
Authors: Wenzel Patrick , von Figura Guido
Published: November 2021

Das Pankreaskarzinom bleibt trotz moderner Diagnostik und zielgerichteter Therapien prognostisch sehr ungünstig. Gründe sind das bei Diagnose häufig fortgeschrittene oder metastasierte Stadium und die Tumorbiologie. Der Beitrag gibt einen Überblick über Differenzialdiagnosen, eine sinnvolle Diagnostik, die Verbesserung der operativen Therapie, Möglichkeiten palliativer Chemotherapien sowie die Therapie bei BRCA-Mutation.
Primäre ZNS-Lymphome mit Bonner Protokoll heilbar?
Authors: Klein Friederike
Published: November 2021

Primäre ZNS-Lymphome (PZCNSL) sind hoch aggressive diffuse B-Zell-Lymphome mit einer besonders schlechten Prognose. In den letzten 20 Jahren wurden Versuche unternommen, Therapien zu etablieren, die eine Ganzhirnbestrahlung vermeiden oder deren Dosis minimieren, um kognitive Einschränkungen zu vermeiden. Eine Option stellt das Bonner Protokoll dar.
Initial Assessment of the Facial Trauma Patient
Authors: Esonu Onyi , Sardesai Maya G.
Published: November 2021

The initial evaluation of the craniofacial trauma patient must be systematic, thorough, and consistent to ensure that injuries are not missed. Life-threatening conditions are first identified using ATLS principles, and focused head and neck examination conducted by a specialist then follows. Imaging is used to guide operative planning, as many craniofacial injuries ultimately benefit from repair to prevent permanent cosmetic or functional deformity. Peri-operative care is often multi-disciplinary in nature, and specialist consultation should be performed in an efficient fashion. Finally, it should be noted that surgeons operating in the maxillofacial region are at high risk for transmission of COVID-19, and risk of COVID-19 sequelae must be balanced with risks associated with the delay of treatment of craniofacial injury.
Analytical modeling for the calculation of underground train-induced vibrations in inhomogeneous soils with uncertainty
Authors: Sun Honglei , Fang Yuchao , Yuan Zonghao , Weng Zhenqi , Ni Dingyu
Published: November 2021

In this paper, an analytical wave function method was used to calculate the underground train-induced vibrations with the inhomogeneous soils taken into account. The wave function method is suitable for solving dynamic problems of multi-layered soils; therefore, inhomogeneous soils with uncertainty could be achieved by assigning different soil parameters to each soil layer. Based on the method, a half-space dynamic model with a viscoelastic cylinder tunnel was established. The dynamic shear modulus of the soil was the main uncertain variable in this study, and models with different load frequencies are compared to analyze the effect caused by the uncertainty. According to the numerical results, the relationship between the uncertainty of the soil modulus and the dynamic response of the model was given. When the dynamic shear modulus changes randomly with the range of 20%, the vertical displacement of the surface can be from 1.02 to 1.12 times to that in the model where the soil is homogeneous, while the displacement of the tunnel vault is 1.03–1.1 times.
Fast homoepitaxial growth of (100) β-Ga2O3 thin films via MOVPE
Authors: Chou Ta-Shun , Seyidov Palvan , Bin Anooz Saud , Grüneberg Raimund , Tran Thi Thuy Vi , Irmscher Klaus , Albrecht Martin , Galazka Zbigniew , Schwarzkopf Jutta , Popp Andreas
Published: November 2021

A high growth rate process above 1 µm/h was achieved for Si-doped (100) β-Ga2O3 homoepitaxial films grown via metalorganic vapor phase epitaxy (MOVPE) while maintaining high crystalline perfection up to a film thickness of 3 µm. The main growth parameters were investigated to increase the growth rate and maintain the step-flow growth mode, wherein the enhanced diffusion channel due to the formation of a Ga adlayer was proposed to be the possible growth mechanism. Si doping allowed precise control of the n-type conductivity of the films with electron concentrations ranging from 1.5 × 1017 to 1.5 × 1019 cm−3 and corresponding mobilities from 144 to 21 cm2 V−1 s−1, as revealed by Hall effect measurements at room temperature. Secondary ion mass spectrometry confirmed homogeneous Si doping through the film and a one-to-one correlation between the Si concentration and the electron concentration. Low defect density in the films was determined by x-ray diffraction measurements. The demonstration of a high growth rate process of β-Ga2O3 films with μm level thickness and smooth surface morphology via MOVPE is critical for high power electronics with vertical device architecture.
Energy gap estimation of zinc sulfide metal chalcogenide nanostructure semiconductor using genetically hybridized support vector regression
Authors: Aldhafferi Nahier
Published: November 2021

Zinc sulfide is a metal chalcogenide semiconductor with promising potentials in environmental sensors, short wavelength light emitting diodes, biomedical imaging, display light sources, transistors, flat panel displays, optoelectronics, and photocatalysis. Adjusting the energy gap (EG) of zinc sulfide for light response enhancement that is suitable for desired applications involves foreign material incorporation through chemical doping or co-doping mechanisms with structural distortion and host symmetry breaking. This work optimizes support vector regression (SVR) parameters with a genetic algorithm to develop a hybrid genetically optimized SVR (HGSVR-EG) model with the precise capacity to estimate the EG of a doped zinc sulfide semiconductor using the crystal lattice constant and the crystallite size as descriptors. The precision of the developed HGSVR-EG model is compared with that of the stepwise regression based model for EG estimation (STR-EG) using different error metrics. The developed HGSVR-EG model outperforms the STR-EG model with a performance improvement of 64.47%, 74.52%, and 49.52% on the basis of correlation coefficient, mean squared error, and root mean square error, respectively. The developed HGSVR-EG model explores and investigates the zinc sulfide bandgap reduction effect of manganese and chromium nano-particle incorporation in the host semiconductor, and the obtained EGs agree well with the measured values. The developed HGSVR-EG model was further validated with an external set of data, and an excellent agreement between the measured and estimated EGs was obtained. The outstanding performance of the developed predictive models in this work would ultimately facilitate EG characterization of zinc sulfide without experimental stress.
Solar-blind ultraviolet photodetectors with thermally reduced graphene oxide formed on high-Al-content AlGaN layers
Authors: Pandit Bhishma , Cho Jaehee
Published: November 2021

Solar-blind deep-ultraviolet (UV) photodetectors (PDs) with high responsivity and fast response have attracted significant attention in environmental, industrial, biological, and military applications. AlGaN is a representative semiconductor material in the field of solar-blind detection; semiconductor performance can be accelerated by combining it with high-transparency, high-stability contact electrode materials. In this study, solar-blind deep-UV metal–semiconductor–metal (MSM) PDs were fabricated based on two-dimensional reduced graphene oxide (rGO) contacts formed on various high-Al-content AlGaN semiconductors. A low dark current in the order of a few picoamperes and a fast photoresponse time of a few tens of milliseconds were confirmed. The investigation of the effects of front- and back-side illumination showed that the photocurrents and corresponding responsivities of the PDs drastically improved under back-side illumination. In detail, the peak locations of the responsivity–wavelength curves were downshifted from 290 nm with a responsivity of 0.0518 A/W for the rGO/Al0.5Ga0.5N MSM PD to 250 nm with a responsivity of 0.0113 A/W for the rGO/Al0.7Ga0.3N MSM PD under back-side illumination. These results indicate that rGO contacts on AlGaN provide a viable approach for developing solar-blind deep-UV PDs.
Effect of Schottky barrier height on quantitative analysis of deep-levels in n-type GaN by deep-level transient spectroscopy
Authors: Aoshima Keito , Horita Masahiro , Suda Jun
Published: November 2021

Deep-level transient spectroscopy (DLTS) using Schottky barrier diodes (SBDs) is widely used for quantitative analysis of deep levels. This study focuses on the dependence of Schottky barrier height on apparent time constants and concentrations of electron traps in n-type GaN. DLTS using SBDs with various barrier heights was carried out. Experimental data show that large reverse leakage currents due to low barrier heights resulted in underestimation of time constants and concentrations. Theoretical calculations considering the impact of leakage currents reproduced experimental results well. Based on the calculations, we suggest a minimum required barrier height where accurate time constants and concentrations can be evaluated.
Quantifying the durability of transition metal nitrides in thermoplasmonics at the single-nanoparticle level
Authors: Setoura Kenji , Ito Syoji
Published: November 2021

Heat generation of plasmonic nanoparticles under photo-illumination is of great use as nanoscale sources for chemical reactions and materials processing; the term thermoplasmonics has been infiltrating in the research fields related to nanotechnology, which represents photothermal effects in plasmonics. In recent years, transition metal nitrides have attracted much attention as thermoplasmonic materials because of their excellent thermal properties compared with those of noble metals. The transition metal nitrides such as titanium nitride (TiN) and zirconium nitride (ZrN) exhibit optical properties similar to gold, and their melting points are very high; for instance, the melting points are 1337 and 3253 K for gold and ZrN, respectively. However, nanometer-sized materials are known to melt at lower temperatures compared with bulk melting points (e.g., around 580 K for gold nanoparticles); this phenomenon is called surface melting, premelting, surface diffusion, or photothermal reshaping. In the present work, we evaluated threshold temperatures of the laser-induced photothermal reshaping of ZrN nanocubes by the scattering micro-spectroscopy at the single-nanoparticle level. As a result, the threshold temperatures of the photothermal reshaping ranged from 1400 to 2100 K; these temperatures are much higher than that of the gold nanoparticles. This work proved that the transition metal nitrides are suitable for thermoplasmonics at higher temperatures compared to the noble metals.
StWRKY13 promotes anthocyanin biosynthesis in potato (
Authors: Zhang Huiling , Zhang Zhonghua , Zhao Yanan , Guo Dalong , Zhao Xijuan , Gao Wen , Zhang Juping , Song Botao
Published: November 2021

Although the role of WRKY transcription factors (TFs) in colour formation has been reported in several species, their function in potato (Solanum tuberosum L.) anthocyanin biosynthesis remains unclear. In this study, the potato WRKY gene StWRKY13 was isolated and characterised. Expression analysis revealed a significantly higher StWRKY13 expression in chromatic tubers than in yellow ones. Transient activation assays showed that StWRKY13 could enhance the role of StAN2 in promoting anthocyanin biosynthesis in tobacco (Nicotiana tabacum L.). Over-expressing the StWRKY13 gene promoted anthocyanin biosynthesis in potato tubers. Further investigations indicated that StWRKY13 could interact with the StCHS, StF3H, StDFR, and StANS gene promoters and significantly enhance their activities. Our findings showed that StWRKY13 could promote anthocyanin biosynthesis by activating StCHS, StF3H, StDFR, and StANS transcription in potato tubers, thereby supporting the theoretical basis for anthocyanins formation in coloured potato tubers.
The small molecule Zaractin activates ZAR1-mediated immunity in
Arabidopsis
Authors: Seto Derek , Khan Madiha , Bastedo D. Patrick , Martel Alexandre , Vo Trinh , Guttman David , Subramaniam Rajagopal , Desveaux Darrell
Published: November 2021

Significance

Pathogenic microbes inject virulence proteins, termed effectors, into the cells of their hosts where they sabotage the cellular machinery and promote the infection process. However, plant and animal cells have evolved the ability to sense the molecular activities of these pathogenic proteins and mount an immune response to protect against infection. Here we have identified a chemical that mimics the immune eliciting activity of a pathogenic effector protein and importantly, it also activates immune responses in plants. We showcase how the intricate molecular dialog of the host–pathogen interface can be used to uncover chemical immunogens that specifically activate the eukaryotic immune system to prevent disease.
Comparison of international tourist profiles in the Spanish wine and olive oil PDOs.
Authors: Barreal Pernas Jesús , Jannes Gil
Published: November 2021

This chapter, by Jesús Barreal Pernas and Gil Jannes, deals with gastro-tourism in Spain and studies the international tourist profile in the Spanish wine and olive oil Protected Destinations of Origin (PDOs). Specifically, the study focuses on regions that have such PDOs and examines the differences and similarities among the profiles of international tourists that visit them. The study concludes with a classification of four clusters according to demographic, travel and motivational characteristics of tourists in the particular area.
Lamb-dip cavity ring-down spectroscopy of acetylene at 1.4 μm
Authors: Fasci E , Gravina S , Porzio G , Castrillo A , Gianfrani L
Published: November 2021

Doppler-free saturated-absorption Lamb dips are observed for weak vibration-rotation transitions of C2H2 between 7167 and 7217 cm−1, using a frequency-comb assisted cavity ring-down spectrometer based on the use of a pair of phase-locked diode lasers. We measured the absolute center frequency of sixteen lines belonging to the 2

ν

3

+

ν

5

1

band, targeting ortho and para states of the molecule. Line pairs of the P and Q branches were selected so as to form a ‘V’-scheme, sharing the lower energy level. Such a choice made it possible to determine the rotational energy separations of the excited vibrational state for J-values from 11 to 20. Line-center frequencies are determined with an overall uncertainty between 3 and 13 kHz. This is over three orders of magnitude more accurate than previous experimental studies in the spectral region around the wavelength of 1.4 μm. The retrieved energy separations provide a stringent test of the so-called MARVEL method recently applied to acetylene.
Spatial analysis for crowds in multi-directional flows based on large-scale experiments
Authors: Cao Shuchao , Sun Feiyang , Chraibi Mohcine , Jiang Rui
Published: November 2021

In this paper, spatial analysis for the nearest neighbors is performed in the unidirectional, bidirectional and crossing flows. Based on the intended direction given in the experiment, different types of neighbors such as U-ped (neighbor with the same intended direction), B-ped (neighbor with the opposite intended direction) and C-ped (neighbor with the intersecting intended direction) are defined. The preferable positions of these neighbors during movement are investigated under various conditions. The spatial relation is quantified by calculating the distance and angle between the reference pedestrian and neighbors. The results indicate that the distribution of neighbors is closely related to the neighbor’s order, crowd density, neighbor type and flow type. Furthermore, the reasons that result in these distributions for different neighbors are explored. Finally neighbor distributions for different flows are compared and the implications of this research are discussed. The spatial analysis sheds new light on the study of pedestrian dynamics in a different perspective, which can help to develop and validate crowd models in the future.
A machine-learning model for the prediction of aggregated building heating demand from pan-European land-use maps
Authors: Peronato G , Boghetti R , Kämpf J H
Published: November 2021

Aggregated building energy demand is a useful indicator for urban energy planning. It can be used by planners and decision-makers to identify clusters of high energy demand in a given urban area and efficiently plan, for example, district heating networks. Various data sources exist at the pan-European level describing land use and built areas. Combined with statistical data, such maps have been used in previous research for estimating building energy performance aggregated at the hectare level, using engineering assumptions. In this paper, we show that large-scale land-use maps alone can be used for predicting annual building energy demand with an accuracy comparable to the one of previous engineering models. We hence present a preliminary method based on Convolutional Neural Networks at different spatial resolutions. The resulting model was trained and tested in an area of about 170 km1 in Geneva (Switzerland) using a local annual heating demand dataset comprising 16239 buildings. On a 300-m aggregation tile, the obtained mean error (14.3%) is significantly reduced compared to the one of a simple linear model (37.2%). Using solely land-use data, we also achieve similar results for a 100-m tile as those of an engineering model from the literature.
Benchmarking of data predictive control in a real-life apartment during heating season
Authors: Huber Benjamin , Bünning Felix , Decoussemaeker Antoon , Heer Philipp , Aboudonia Ahmed , Lygeros John
Published: November 2021

Model Predictive Control is an energy efficient climate control strategy in buildings. However, the effort associated with physics-based modelling seems to prevent widespread application in residential buildings. Applying machine-learning algorithms on historical data promises efficient generation of predictive models for control. In a recent experimental study, Data Predictive Control based on random forests and linear models outperformed a baseline controller during cooling season. In this paper, the approach is benchmarked against hysteresis control and conventional Model Predictive Control based on an RC-network model during heating season. Data Predictive Control shows promising results in terms of energy consumption and thermal comfort.
Temperature level optimization for low-grade thermal networks using the exergy method
Authors: Adihou Yolaine , Kane Malick , Ramousse Julien , Souyri Bernard
Published: November 2021

Low-temperature thermal networks open the field for additional renewable and recovered energy sources to be used. The exploitation of low exergy level resources requires decentralized heat pumps having a significant impact on the network's overall electricity consumption. Thus, a compromise must be found in order to minimize thermal and electrical consumption while integrating a maximum of renewable energy sources. This optimum is governed by the temperature level of the network. This paper aims at determining the optimal network temperature using the exergy criterion. The exergy method is detailed and applied to the multi-source network blueCAD (Fribourg) fed by geothermal energy, and FriCAD, a high temperature district heating network. The optimum temperature decreases as the share of geothermal energy in the production increases. For blueCAD, it ranges from 40 to 55 °C.
Experiment strategy for evaluating advanced building energy management system
Authors: Cai Hanmin , Khayatian Fazel , Heer Philipp
Published: November 2021

Buildings are envisioned to play an active role in future low-carbon energy systems. The complexity of building energy management systems increases as they interface more and more subsystems and domains. As an important step to achieve a higher technology readiness level, these energy management systems need to be systematically tested in real-life conditions. Currently, there are no standard testing and experiment strategies in buildings to handle the mentioned complexity. Additionally, the levels of details reported in the existing experimental studies are heterogeneous. This paper summarizes an application of a holistic testing method to a flexible fully-equipped prosumer with the goal of facilitating test preparation, execution, replication, and comparison. Several empirical suggestions are provided, and a hybrid quantification strategy with digital twins is presented.
Industrial Waste Heat District-Heating Design Based on Geographic Information System: Case Study in Vitoria-Gasteiz (Spain)
Authors: Lumbreras Mikel , Diarce Gonzalo , Martin-Escudero Koldobika , Campos-Celador Alvaro , Larrinaga Pello
Published: November 2021

The use of georeferenced information system and Light Detection and Ranging (LiDAR) data in combination with traditional data analytics tools is very promising in urban scale engineering and especially in energy urban planning. This paper explores the use of new DH networks for industrial waste heat exploitation and for that purpose, a case-study in Vitoria-Gasteiz (Spain) is proposed. The methodology explained in this paper explores the incorporation of data from industrial emplacements, buildings and road network in order to identify optimal areas in the city for the construction of a new district-heating network. An area of influence of a buffer of radius 1.5km from the industry location is defined and the proposed algorithm divides this area into grids of different sizes. The path for the network is calculated by optimizing the economic performance of the network. The results show that the district-heating may be built in the south-west direction from the industry and among the 40 configurations studied, payback periods from 6 to 8.5 years are obtained.
Development and initial tests of an urban comfort monitoring system
Authors: Chiesa Giacomo , Yingjun Luo , Yuxuan Sheng , Guoxin Wang , Bolun Zhang
Published: November 2021

The paper presents a newly developed low-cost measurement system for outdoor comfort monitoring. The solution is based on IoT (Internet of Things) technologies and is cloud-connected. The system is able to collect physical environment data, and includes a movable GPS monitoring station as well as the subjective thermal sensation of pedestrians via a devoted app. The cloud interface promptly elaborates the received data to calculate outdoor thermal comfort indices such as UTCI (Universal Thermal Climate Index), MRT (mean radiant temperature), and ET (effective temperature). The system is conceived for supporting both fixed and traveling measurements, and to support correlation studies between monitored environmental variables and personal comfort sensations to promote the local adaptation of comfort indices. Results from early testing are also reported.
Evaporative cooling strategies in urban areas: The potential of vertical greening systems to reduce nocturnal heat stress
Authors: Görgen Fabian , Rossi-Schwarzenbeck Monica
Published: November 2021

This research is part of a project that aims to create a simulation workflow to design adaptive facades to not only reduce the energy demand of buildings and provide a good level of indoor comfort. but also to mitigate the urban heat island effect. The anthropogenic climate change results in a steady increase of hot days. tropical nights and heavy rainfall. affecting the quality of human comfort. especially in urban areas not only in hot regions of the world but also in Central Europe. Vertical greening systems are often a first-choice mitigation strategy to improve the deteriorating situation. By combining the use of natural resources like rainwater and solar radiation. the greening evaporates water and provides natural cooling. This paper deals with the efficiency and feasibility of vertical greening systems towards a relief in heat stress by simulating different constructions under local circumstances of three climate zones. focusing on the night-time. To carry out the simulations with microclimate simulation tool ENVI-met. an urban apartment complex was designed and provided with different kinds of vertical greening to investigate the various positive effects resulting from the green façade. As a shading device. the greened walls showed a significant decrease of wall surface temperatures of up to 18K. However. restricted transpiration fluxes obstruct exploiting the full potential of evaporative cooling. especially during night-time.
Integrated analysis of regional energetic demand and renewable energy potentials at the example of Ludwigsburg county, Germany
Authors: Kesnar Chris , Weiler Verena , Neuhäuser Julia , Schröter Bastian
Published: November 2021

This work compares heating and electricity demands with local renewable energy potentials at the example of Ludwigsburg county, a mostly suburban region in South-Western Germany. Bottom-up analyses of the energetic potentials are performed within an established regional energy simulation platform and are thus based on a consistent set of geoinformatic data. This approach has two advantages compared to a top-down analysis or using multiple specialized tools: it allows assessing energetic potentials in high spatial resolution and relates it to heating and electricity demands on a single-building scale. Secondly, it is transferable to other regions due to the widespread availability of most input data. Our results show that exploiting technical potentials for bioenergy, rooftop PV, wind onshore, and hydropower can cover 68% of electricity demand 7% of heat demand in 2019, indicating that energy autonomy is difficult to achieve for densely populated regions in Europe.
Retrofitting solutions for a campus building to mitigate urban heat island in a hot humid climate
Authors: Patil Vajreshwari , Bizcarguenaga Maite , Lieberknecht Katherine , Felkner Juliana
Published: November 2021

In this study we examine the summer cooling effects of trees and green facades on reducing urban heat island effects. Using ENVI-met model simulations, we investigate the influence of added greenery on the surface and ambient air temperature and its role on air fluctuations in the hot humid climate of Austin, TX, at pedestrian height. Under the specific conditions considered in this model, the results show the combination of trees and green facades has a greater cooling effect. Added greenery to the building mostly impacts the building's surface temperature during the hottest hours of the day, registering a maximum surface temperature reduction of 20.33°C. Simulations also show a maximum overall potential air temperature reduction of 0.54°C, and a maximum potential air temperature cooling effect near the building of 0.91°C. Future research should be conducted to address this study's limitations. Nevertheless, these findings can provide architects, designers, planners, and policymakers with a better understanding of the many benefits trees and green facades have, and provide them with the necessary tools to implement new solutions across sectors and scales to reduce the impacts urban areas have on the environment and provide a better living for all.
Development of a freely distributable CFD tool for approximate and detailed simulations of the flow around a complex of buildings
Authors: Decaix J , Jaboyedoff P , Duthé G. , El Sergany E. , Aiulfi L.
Published: November 2021

Indo-Swiss Building Energy Efficiency Project (BEEP) is a cooperation project between the Ministry of Power, Government of India, and the Federal Department of Foreign Affairs of the Swiss Confederation. Started in 2011, the project’s central focus is to help India mainstream Energy-Efficient and Thermally Comfortable (EETC) Building Design. BEEP works with building industry, policy makers, and building owners to catalyse adoption of EETC building design and technologies. India wants to avoid or reduce the use of air conditioning by improving natural ventilation at night, which requires numerical simulations to compute the flow around the buildings. However, the simulations of fluid flows are time consuming and are not used at the beginning of a project when the locations of the buildings are set. To improve the situation, a freely distributable environment based on the OpenFOAM toolbox has been developed providing two levels of resolution: an approximate level computing the flow in few minutes and a RANS level of simulation. The user inputs are limited to the geometry and the velocity direction and magnitude. The mesh and the numerical set up are automated. The accuracy of the two levels of resolution have been checked by computing test cases from the CEDVAL database.
Monitoring of photovoltaic systems and evaluation of building energy self-consumption
Authors: Cillari Giacomo , Fantozzi Fabio , Franco Alessandro
Published: November 2021

The spread of nearly zero energy buildings (nZEB), promoted by the strategies set in the path of decarbonisation, has made the integration of renewable energy systems (RES) in buildings a common and strategic practice; in particular, they most involve small to medium building integrated photovoltaic (BIPV) systems coupled with heat pumps (HPs). One major challenge deals with the implementation of high self-consumption (SC) schemes for the energy produced on site, essential to carry on a wider implementation of photovoltaic systems. The present paper addresses the effect of different sizing strategies on the SC levels of 3 systems installed on traditional and nZEB houses, with a peak power between 3.12 kWp and 5.98 kWp. The systems have been monitored recording the various energy flows involved. Different optimization strategies have been tested with the purpose of minimizing the interaction with the grid, according to SC and self-sufficiency (SS) indexes. The aim is to provide design guidelines for the correct sizing in a bottom-up approach. Results underlined the fundamental role of storage technologies. Approximately 6 Wp/m2 assure an optimal energy employment without storage, with SS index below 35%: the integration of small storage, 3-7 kWh/kWp leads to SS and SC index above 60% and 88% respectively.
Hydrogen-based electricity storage optimization on buildings by coupling thermal and photovoltaic electricity production towards carbon neutrality
Authors: Morier Y , Aguacil Moreno S , Couty P
Published: November 2021

Self-sufficiency (SS) of buildings with low greenhouse gas (GHG) emissions can be obtained using photovoltaics (PV). To maximize self-consumption - minimizing the import of grid electricity - PV can be coupled with a hydrogen storage system converting the electricity to hydrogen by electrolysis during the summer season, when the on-site production is higher, and using it during the winter season with fuel cells. This article deals with the sizing constraints of solar hydrogen systems at building-scale. The future building for the Smart Living Lab (SLL) in Fribourg (Switzerland) has been taken as case study. It has four stories and a mixed usage (Office-building and Research facilities), with a multi-oriented PV installation in order to produce enough electricity to achieve at least 50% of self-sufficiency. Using the PV production, this study aims to optimise the sizing of a hydrogen storage system allowing to reach the required self-sufficiency ratio. Finally, a comparison of the global efficiency of the system for three different demand-side scenarios.
Solar Thermal Regeneration of Borehole Heat Exchangers in Urban and Suburban Districts
Authors: Sauter David , Hunziker Manuel , Poppei Joachim , Cochand Fabien , Hubbuch Markus , Rohrer Jiirg
Published: November 2021

To prevent undercooling of the ground in densely populated areas, regeneration of borehole heat exchangers (BHEs), for example by solar thermal heat, may become necessary. However, the usable roof area is often small compared to the building’s heat demand, especially in urban areas. It was investigated how much regeneration is possible in districts that are supplied entirely by heat pumps with BHEs. Example buildings were modelled based on the buildings of two districts in Zurich. Uncovered PVT collectors and glazed flat-plate collectors were used as regeneration sources. The possible regeneration was determined in a simulation process that included the effects of mutual influences between the BHEs of neighbouring buildings. As expected, glazed flat-plate collectors allow for more regeneration than uncovered PVT collectors. For full regeneration, the required usable roof area relative to the annual heat demand is about 1.8m2/MWh for PVT and 1.2m2/MWh for flat-plate collectors. Large buildings often do not provide sufficient roof area for full regeneration. A sustainable heat supply of the entire district with regenerated BHEs can be possible in suburban neighbourhoods, if the bigger buildings are distributed rather evenly. In urban neighbourhoods, areas may exist in which solar thermal regeneration alone is not sufficient.
An energy-economic analysis of real-world hybrid building energy systems
Authors: Sawant Parantapa , Braasch Christian , Koch Manuel , Bürger Adrian , Kallio Sonja
Published: November 2021

A coordinated operation of decentralised micro-scale hybrid energy systems within a locally managed network such as a district or neighbourhood will play a significant role in the sector-coupled energy grid of the future. A quantitative analysis of the effects of the primary energy factors, energy conversion efficiencies, load profiles, and control strategies on their energy-economic balance can aid in identifying important trends concerning their deployment within such a network. In this contribution, an analysis of the operational data from five energy laboratories in the trinational Upper-Rhine region is evaluated and a comparison to a conventional reference system is presented. Ten exemplary data-sets representing typical operation conditions for the laboratories in different seasons and the latest information on their national energy strategies are used to evaluate the primary energy consumption, CO2 emissions, and demand-related costs. Various conclusions on the ecologic and economic feasibility of hybrid building energy systems are drawn to provide a toe-hold to the engineering community in their planning and development.
Residential rooftop PV power generation to support cooling loads and national targets in Saudi Arabia
Authors: Alam M , Alghamdi A S , Bahaj A S , James P A B , Blunden L S
Published: November 2021

Saudi Arabia (SA) has a high per capita electricity consumption, predominantly supplied from fossil fuels. The residential sector accounts for about 50% of total electricity consumption with approximately 70% of which is used for air-conditioning (AC) loads. This research investigates the role of rooftop photovoltaic (PV) systems to displace cooling loads, hence reducing residential electricity demand. Daily and annual electrical demands were monitored in a villa in Jeddah, and a range of PV systems were modelled to determine their ability to support AC and other household loads. Seasonal performance data of such systems were compared to monitored load variations to understand variability and yields. The monitored electrical demand of the villa was in the range 66-167 kWh/day which was used to estimate the required PV systems’ capacities. The results indicate that PV systems in the range 2-10 kWp present significant shortfall to support the full demand. However, a 15kWp system was found to meet the daytime total loads. These results indicate that appropriately sized rooftop PV-systems can shave-off peak air-conditioning loads. The paper discusses the importance of utilising building integrated PV in such applications in SA, and highlights the need for dissemination at scale through country wide policy framework.