bluuebunny/crossref_metadata_2025 huggingface dataset:
Ensemble‐based glioma grade classification using Gabor filter bank and rotation forest
Authors: Singh Rahul , Goel Aditya , Raghuvanshi D.K.
Published: February 2021

This work aims at developing an automated ensemble‐based glioma grade classification framework that classifies glioma into low‐grade glioma (LGG) and high‐grade glioma (HGG). Discriminant features are extracted using the Gabor filter bank and concatenated in a vectorised form. The feature set is then divided into k subsets of features. An ensemble of base classifiers known as rotation forest is employed for classification purpose. Independent components analysis (ICA) is applied on every feature subset and independent features are extracted. Each classifier in the ensemble is trained with these independent features from all the subset of features. These k feature subsets are responsible for different rotations during the training phase. This results in classifier diversity in the ensemble. Extensive experiments are conducted on benchmark BraTS 2017 data set and comparative analysis reveals that the proposed framework outperforms the competitive techniques in terms of various performance metrics. Data‐augmentation technique, synthetic minority over‐sampling technique is applied to oversample minority class samples alleviate class biasness problem. The proposed classification framework achieves an accuracy of 98.63%, dice similarity coefficient of 0.98 and sensitivity of 0.96. The authors conduct different comparative experiments with state‐of‐the‐art ensemble‐based, deep learning‐based and traditional machine learning‐based classification approaches to validate the performance of the proposed framework.
DEC‐LADE: Dual elliptic curve‐based lightweight authentication and data encryption scheme for resource constrained smart devices
Authors: Rao Vidya , K. V. Prema
Published: February 2021

The fast growth in Internet‐of‐Things (IoT) applications has increased the number of end‐devices communicating over the Internet. As these resource‐constrained devices are connected over the Internet, they are exposed to various security and privacy issues. Traditionally, to provide end‐to‐end security, research efforts have been carried out using elliptic curve cryptography‐based authentication schemes. These existing schemes use a single set of elliptic curve parameters to generate the public and private keys, which are prone to be hacked under intense cryptanalysis. Thereby to increase the security strength the proposed method uses two sets of dynamic elliptic curves for performing digital signature and encryption processes. The method is evaluated on a client‐server model using the Raspberry Pi‐3 device. Herein, the choice of elliptic curves is made random at the client node and the reference of each elliptic curve is exchanged with the server during the key‐exchange process. The choice of elliptic curves is delegated to the client machine to avoid the unwanted delay that would be encounter if server had to choose the curve. This is done because the client senses the data at regular intervals of time and forwards it to the server securely. Experiments were conducted to measure the time taken for hashing function, key generation, signature generation, signature verification, encryption and decryption process. On comparing the proposed DEC‐LADE with cBLAKE2b, an improvement was seen at 13.76%, 2.57%, 18.36%, 6.12%, 9.91% and 6.08% less time, respectively, than LWDSA with mBLAKE2b. Theoretical and real‐time security evaluations are performed for man‐in‐the‐middle attack, replay attack, and a denial‐of‐service attack.
Chirp mass–distance distributions of the sources of gravitational waves
Authors: Ossowski M.
Published: February 2021

Context. The detection of gravitational waves emitted by binary black holes raises questions regarding the origin of binaries. There are several models in the literature involving binary evolution in both the field and clusters.

Aims. We compare the predictions of these models with observations and establish the reliability of this comparison.

Methods. We use the likelihood calculation to compare the models in the space spanned by the observed chirp mass and the luminosity distance of the source.

Results. We rank the models by their ability to explain all current gravitational wave detections. It is shown that the most probable models correspond to binary evolution with low metallicity. Several variants of such evolution have similar likelihoods. The globular cluster model, considered here, is disfavoured.

Conclusions. We present the usefulness of the method in distinguishing between models when new observations become available. We calculate the number of observations required to distinguish between each pair of models. We find that the number varies from ten to several thousand for some pairs of models, yet almost two-thirds of pairs are distinguishable with at most 100 observations.
Gemini/Phoenix H-band analysis of the globular cluster AL 3
Authors: Barbuy B. , Ernandes H. , Souza S. O. , Razera R. , Moura T. , Meléndez J. , Pérez-Villegas A. , Zoccali M. , Minniti D. , Dias B. , Ortolani S. , Bica E.
Published: February 2021

Context. The globular cluster AL 3 is old and located in the inner bulge. Three individual stars were observed with the Phoenix spectrograph at the Gemini South telescope. The wavelength region contains prominent lines of CN, OH, and CO, allowing the derivation of C, N, and O abundances of cool stars.

Aims. We aim to derive C, N, O abundances of three stars in the bulge globular cluster AL 3, and additionally in stars of NGC 6558 and HP 1. The spectra of AL 3 allows us to derive the cluster’s radial velocity.

Methods. For AL 3, we applied a new code to analyse its colour-magnitude diagram. Synthetic spectra were computed and compared to observed spectra for the three clusters.

Results. We present a detailed identification of lines in the spectral region centred at 15 555 Å, covering the wavelength range 15 525–15 590 Å. C, N, and O abundances are tentatively derived for the sample stars.
Energetic particle behavior in near-Sun magnetic field switchbacks from PSP
Authors: Bandyopadhyay R. , Matthaeus W. H. , McComas D. J. , Joyce C. J. , Szalay J. R. , Christian E. R. , Giacalone J. , Schwadron N. A. , Mitchell D. G. , Hill M. E. , McNutt R. L. , Desai M. I. , Bale S. D. , Bonnell J. W. , Dudok de Wit T. , Goetz K. , Harvey P. R. , MacDowall R. J. , Malaspina D. M. , Pulupa M. , Kasper J. C. , Stevens M.
Published: February 2021

Context. The observation of numerous magnetic switchbacks and associated plasma jets in Parker Solar Probe (PSP) during its first five orbits, particularly near the Sun, has attracted considerable attention. Switchbacks have been found to be systematically associated with correlated reversals in the direction of the propagation of Alfvénic fluctuations, as well as similar reversals of the electron strahl.

Aims. Here we aim to see whether the energetic particles change direction at the magnetic field switchbacks.

Methods. We use magnetic field data from the MAG suite’s fluxgate magnetometer instrument to identify switchback regions. We examine the radial anisotropy of the energetic particles measured by the EPI-Lo instrument of the IS⊙IS suite.

Results. We find that energetic particles measured by EPI-Lo generally do not preferentially change their directionality from that of the background magnetic field to that of the switchbacks.

Conclusions. A reasonable hypothesis is that particles with smaller gyroradii, such as strahl electrons, can reverse direction by following the magnetic field in switchbacks, but that larger gyroradii particles cannot. This provides the possibility of setting a constraint on the radius of the curvature of the magnetic field in switchbacks, a property not otherwise observed by PSP. We expect that particles at higher energies than those detectable by EPI-Lo will also not respond to switchbacks. The observed reversals of radial energetic particle flux are separate phenomena, likely associated with source locations or other propagation effects occurring at greater radial distances.
KMT-2018-BLG-1025Lb: microlensing super-Earth planet orbiting a low-mass star
Authors: Han Cheongho , Udalski Andrzej , Lee Chung-Uk , Albrow Michael D. , Chung Sun-Ju , Gould Andrew , Hwang Kyu-Ha , Jung Youn Kil , Kim Doeon , Kim Hyoun-Woo , Ryu Yoon-Hyun , Shin In-Gu , Shvartzvald Yossi , Yee Jennifer C. , Zang Weicheng , Cha Sang-Mok , Kim Dong-Jin , Kim Seung-Lee , Lee Dong-Joo , Lee Yongseok , Park Byeong-Gon , Pogge Richard W. , Kim Chun-Hwey , Kim Woong-Tae , Mróz Przemek , Szymański Michał K. , Skowron Jan , Poleski Radosław , Soszyński Igor , Pietrukowicz Paweł , Kozłowski Szymon , Ulaczyk Krzysztof , Rybicki Krzysztof A. , Iwanek Patryk , Wrona Marcin
Published: February 2021

Aims. We aim to find missing microlensing planets hidden in the unanalyzed lensing events of previous survey data.

Methods. For this purpose, we conducted a systematic inspection of high-magnification microlensing events, with peak magnifications of Apeak ≳ 30, in the data collected from high-cadence surveys in and before the 2018 season. From this investigation, we identified an anomaly in the lensing light curve of the event KMT-2018-BLG-1025. The analysis of the light curve indicates that the anomaly is caused by a very low mass-ratio companion to the lens.

Results. We identify three degenerate solutions, in which the ambiguity between a pair of solutions (solutions B) is caused by the previously known close–wide degeneracy, and the degeneracy between these and the other solution (solution A) is a new type that has not been reported before. The estimated mass ratio between the planet and host is q ~ 0.8 × 10−4 for solution A and q ~ 1.6 × 10−4 for solutions B. From the Bayesian analysis conducted with measured observables, we estimate that the masses of the planet and host and the distance to the lens are (Mp, Mh, DL) ~ (6.1 M⊕, 0.22 M⊙, 6.7 kpc) for solution A and ~(4.4 M⊕, 0.08 M⊙, 7.5 kpc) for solutions B. The planet mass is in the category of a super-Earth regardless of the solutions, making the planet the eleventh super-Earth planet, with masses lying between those of Earth and the Solar System’s ice giants, which were discovered by microlensing.
KMT-2019-BLG-0797: Binary-lensing event occurring on a binary stellar system
Authors: Han Cheongho , Lee Chung-Uk , Ryu Yoon-Hyun , Kim Doeon , Albrow Michael D. , Chung Sun-Ju , Gould Andrew , Hwang Kyu-Ha , Jung Youn Kil , Kim Hyoun-Woo , Shin In-Gu , Shvartzvald Yossi , Yee Jennifer C. , Zang Weicheng , Cha Sang-Mok , Kim Dong-Jin , Kim Seung-Lee , Lee Dong-Joo , Lee Yongseok , Park Byeong-Gon , Pogge Richard W.
Published: February 2021

Aims. We analyze the microlensing event KMT-2019-BLG-0797. The light curve of the event exhibits two anomalous features from a single-lens single-source model, and we aim to reveal the nature of the anomaly.

Methods. It is found that a model with two lenses plus a single source (2L1S model) can explain one feature of the anomaly, but the other feature cannot be explained. We test various models and find that both anomalous features can be explained by introducing an extra source to a 2L1S model (2L2S model), making the event the third confirmed case of a 2L2S event, following MOA-2010-BLG-117 and OGLE-2016-BLG-1003. It is estimated that the extra source comprises ∼4% of the I-band flux from the primary source.

Results. Interpreting the event is subject to a close–wide degeneracy. According to the close solution, the lens is a binary consisting of two brown dwarfs with masses (M1, M2) ∼ (0.034, 0.021) M⊙, and it is located at a distance of DL ∼ 8.2 kpc. According to the wide solution, on the other hand, the lens is composed of an object at the star–brown dwarf boundary and an M dwarf with masses (M1, M2) ∼ (0.06, 0.33) M⊙ located at DL ∼ 7.7 kpc. The source is composed of a late G dwarf to early K dwarf primary and an early-to-mid M dwarf companion.
Les singularités thermiques d’un espace périurbain dans une agglomération de dimension moyenne : le cas de Caen durant l’hiver 2018/2019
Authors: Cantat Olivier , Follin Alexandre
Published: February 2021

L’analyse comparative des données météorologiques de la station rurale de Carpiquet avec une station expérimentale en périphérie de la ville de Caen a permis de montrer la présence en hiver d’un léger îlot de chaleur péri-urbain (ICPU) (moyenne de +0,4°C). Il est caractérisé par un maximum d’intensité en fin d’après-midi et début de soirée (+0,8°C) et des écarts faibles le reste du temps. Derrière cette image moyenne, une analyse du continuum temporel au pas de temps journalier puis horaire a mis en exergue des comportements différenciés selon les types de temps. Le caractère le plus original des résultats est la présence certes rare, mais significative en termes d’intensité, d’un îlot de fraîcheur péri-urbain (IFPU). Il se forme de nuit par temps clair et calme et se prolonge dans la matinée, jusqu’à présenter un maximum d’intensité vers 9 h UTC. Cette inversion par rapport au schéma classique de fonctionnement des îlots de chaleur urbain (ICU) s’explique par un mode d’occupation du sol favorable à la formation d’une poche froide par rayonnement nocturne, favorisée par l’absence totale de vent (effet de barrage du bâti et de la végétation) et par la faible densité urbaine, alors que sur la campagne ces mécanismes de refroidissement sont atténués par la persistance d’un léger flux. Cet IFPU résiste et s’intensifie en début de matinée, jusqu’à temps que le soleil et la turbulence de l’air ne viennent échauffer et disperser cette pellicule d’air froid plus dense. Ici, les conditions stationnelles semblent donc primer sur les effets purement urbains car l’agglomération de Caen ne présente pas une masse suffisante pour créer une « bulle chaude » jusque dans ses quartiers périphériques quand un type de temps radiatif s’impose.
Intensité et spatialisation de l’îlot de chaleur urbain parisien à partir de données participatives
Authors: Madelin Malika , Dupuis Vincent
Published: February 2021

L’îlot de chaleur urbain est une des principales manifestations du climat urbain qui se caractérise par des températures plus élevées en ville qu’à la campagne et peut avoir des conséquences importantes pour les citadins en particulier lors des vagues de chaleur. Par convention, l’intensité de l’îlot est calculée, à partir des données des stations météorologiques de référence, comme la différence de température de l’air entre les zones urbaines et rurales environnantes. Dans cet article, nous cherchons à quantifier cette intensité et son extension sur la région parisienne, à partir d’un jeu de données massives participatives, que nous avons collectées depuis l’été 2017. Nous détaillons l’analyse critique de ces données non homogènes, absolument nécessaire avant leur exploitation scientifique. Nous montrons alors l’existence d’un îlot de chaleur urbain nocturne, dont l’intensité et l’extension spatiale varient selon les saisons et les conditions atmosphériques, avec une intensification lors des nuits radiatives (ciel clair, vent calme). In fine, nous spatialisons cet îlot pour des conditions radiatives et le comparons avec l’îlot de surface, produit à partir des températures de surface MODIS.
Prediction of the time constant of small-scale concentrated solar CHP plants
Authors: Tascioni Roberto , Pirro Matteo , Arteconi Alessia , Del Zotto Luca , Bartolini Carlo M. , Mahkamov Khamid , Mahkamova Irina , Cabeza Luisa F. , De Gracia Alvaro , Pili Piero , Mintsa André C. , Gimbernat Toni , Botargues Teresa , Mullen David , Cioccolanti Luca
Published: February 2021

The operation of a power plant based on solar energy can vary significantly with time because of the intrinsic intermittency of the energy resource. Hence, a smart management is required to deal with the complex dynamic variations of the different subsystems. In order to do that, different control logics can be implemented but their effectiveness strictly depends on the temporal evolution of the parameters considered. For a given plant configuration, their exact estimation can be obtained through experimental tests during the commissioning of the plant. However, any change in the design parameters of the plant reflects in a different time constant, whose preliminary knowledge may be of support in tuning the control logic of the plant during the design stage. Therefore, based on the configuration of a small-scale concentrated solar combined heat and power plant as designed and built under the EU funded project Innova MicroSolar by several universities and companies, in this study a prediction of the time constant of several plant configurations with varying solar multiple and size of the storage tank is performed. By making use of the dynamic simulator previously developed by some of the authors, an estimation of such characteristic is assessed in case of potential redesign of the plant, providing also useful suggestions into the design of the control logic.
Integration of two-stage thermochemical treatment and chemical leaching for extraction of advanced biochar and high value critical raw materials from sewage sludge
Authors: Salimbeni Andre , Rizzo Andrea Maria , Chiaramonti David
Published: February 2021

The proposed study aims at assessing the reliability of a new sludge conversion technology, based on integrating thermochemical treatment, with a chemical leaching stage for producing high quality biochar and valuable liquid with high concentration of phosphorus and other critical elements. The concept is based on the fact that sludge ash usually contains about 25% of CaO, 20% of P2O5, and about 25-30% of SiO2. With the removal of these elements, ash content is drastically reduced. The study is thus composed of two phases: (1) assessment of sludge thermochemical conversion routes, and (2) chemical leaching produced biochar. In the first phase, three thermochemical routes are investigated: HTC of fresh sludge at 80% moisture, slow pyrolysis of dry sludge, slow pyrolysis of HTC solid (hydrochar). In the second phase, the solid obtained by slow pyrolysis (biochar) is upgraded through leaching treatment to extract inorganic valuable elements: P, Mg, K. The first phase of the study demonstrated that processing dry sludge in slow pyrolysis at 450°C allows to obtain a low volatile carbonaceous product with characteristics similar to a thermal coal. Second phase demonstrated that, after acid leaching process using HNO3, ash content in biochar decreased from 41.63% to 16.67%. This method also demonstrated to be a valid solution to extract more than 90% of P, K, and Mg contained in the solid, making these elements available for being recycled in agriculture and other industrial uses. At the same time, the increase of the biochar C content and calorific value makes it a valid substitute of fossil coals.
Experimental study of fast pyrolysis vapors fractionation through different staged condensation configurations
Authors: Mati Alessandro , Buffi Marco , Dell’Orco Stefano , Ruiz Ramiro M.P. , Kersten S.R.A. , Chiaramonti David
Published: February 2021

The quality of biocrudes from fast pyrolysis of lignocellulosic biomass can be improved by optimizing the downstream condensation systems to separate and concentrate selected classes of compounds, thus operating different technological solutions and condensation temperatures in multiple condensation stages. Scientific literature reports that fractional condensation can be deployed as an effective and relatively affordable step in fast pyrolysis. It consists in a controlled multiple condensation approach, which aims at the separated collection of classes of compounds that can be further upgraded to bio-derived chemicals through downstream treatments. In this study, fractional condensation has been applied to a fast pyrolysis reactor of 1 kg h-1 feed, connected to two different condensation units: one composed by a series of two spray condensers and an intensive cooler; a second by an electrostatic precipitator and an intensive cooler too. Fast pyrolysis of pinewood was conducted in a bubbling fluidized bed reactor at 500 °C, while condensable vapours were collected by an interchangeable series of condensers. Using the first configuration, high boiling point compounds – such as sugars and lignin-derived oligomers – were condensed at higher temperatures in the first stage (100 – 170 °C), while water soluble lighter compounds and most of the water were condensed at lower temperatures and so largely removed from the bio-oil. In the first two condensing stages, the bio-oil water content remained below 7 wt % (resulting in 20 MJ kg-1 of energy content) maintaining about 43% of the liquid yield, compared to the 55% of the single step condensation runs. The work thus generated promising results, confirming the interest on upscaling the fractional condensation approach to full scale biorefinering.
Geothermal power plants with improved environmental performance: assessment of the potential for an Italian site
Authors: Fiaschi Daniele , Leveni Martina , Manfrida Giampaolo , Mendecka Barbara , Talluri Lorenzo
Published: February 2021

Geothermal energy is a clean resource, which could significantly contribute to the reduction of greenhouse and other gas emissions by replacing fossil fuels for power generation. In many geothermal sites, the resource contains substantial Non-Condensable Gases (NCGs: CO2 and contaminants), whose emissions can be limited to developing power plant schemes suitable for complete resource reinjection. Organic Rankine or other closed-loop cycles are definitely favored in this light. This work investigates a solution for complete NCG reinjection in the liquid-dominated reservoir conditions typical of the Monte Amiata area (Italy), referring to the specific site of Torre Alfina (IT) which presents a specific attractiveness because of its high pressurization. The solution considered avoids flashing the resource and thus presents an appealing environmental performance. The power plant models include energy and exergy balances, as well as exergo-environmental analysis. The overall environmental performance is evaluated by a simplified (preliminary) Life Cycle Analysis (LCA). Different solutions are compared, considering the possibility of sub- or super-critical power cycles.
Preliminary assessment of a microgrid integrated with a biomass gasification CHP system for a production facility in Central Italy
Authors: Stamponi Ettore , Giorgini Francesco , Cotana Franco , Moretti Elisa
Published: February 2021

The aim to reduce carbon dioxide emissions and to improve buildings energy efficiency has led to develop smart grids to manage electricity and heat. The work deals with the thermal and electric microgrid analysis of the Loccioni Company: the production facility consists of high-energy performance industrial and office buildings, partially powered by produced on-site renewable energy (solar PV, hydropower plants, water ground heat pumps). The challenge of continuous improvement in the use of energy led the company to develop a thermal microgrid for optimal management of the heat produced by a small-scale CHP system (50 kWel/110 kWth). The cogeneration system is based on biomass (pellet) chemical degradation process of gasification. The work discusses preliminary results relating to the first months of the system operation, to highlight the energy benefits and the critical issues. Data are collected by the Company monitoring system and a laboratory feedstock physico-chemical characterization is carried out. The main goal of this paper is to lay the foundations for the development of an energy management system that regulates energy flows between buildings. The development of the thermal microgrid will guarantee not only tangible benefits in terms of energy savings but also an increase in the resilience of the entire building/plant system.
Design of a multi-energy system under different hydrogen deployment scenarios
Authors: Bartolucci Lorenzo , Cordiner Stefano , Mulone Vincenzo , Pasquale Stefano
Published: February 2021

Multi Energy Systems (MES) are effective means to increase Renewable Energy Sources (RES) penetration in the energy system and therefore to move toward a decentralized low-carbon system. Several energy vectors can be integrated together to exploit synergies in a MES framework, such as electricity, heat and hydrogen. The latter is one of the most promising energy carriers to promote widespread use of MES. Predictive management and well-defined sizing methodology are mandatory to achieve maximum performance out of MES. In this study a grid-connected MES consisting of a photovoltaic (PV) plant, a Battery Energy Storage System (BESS) and a Proton Exchange Membrane Fuel Cell (PEMFC) as a programmable Combined Cooling Heat and Power (CCHP) source, is modelled. Natural gas is considered as an alternative fuel to pure hydrogen. Mixed Integer Linear Programming and Genetic Algorithm are used respectively to solve operation and sizing problems. A single-objective optimization approach, including emission factors as optimization constraints, is carried out to find the optimal configuration of the MES. Several future scenarios are studied, considering different percentages of hydrogen in the gas mixture and comparing the techno-economic performance of the system with respect to a pure hydrogen fueling scenario. Results showed that the environmental objective within the design optimization, promote the use of hydrogen, especially in scenarios with high share of green hydrogen.
Optimal design and energy management of a renewable energy plant with seasonal energy storage
Authors: Bahlawan Hilal , Losi Enzo , Manservigi Lucrezia , Morini Mirko , Pinelli Michele , Spina Pier Ruggero , Venturini Mauro
Published: February 2021

The exploitation of fossil fuels is undoubtedly responsible of environmental problems such as global warming and sea level rise. Unlike energy plants based on fossil fuels, energy plants based on renewable energy sources may be sustainable and reduce greenhouse gas emissions. However, they are unpredictable because of the intermittent nature of environmental conditions. For this reason, energy storage technologies are needed to meet peak energy demands thanks to the stored energy. Moreover, the renewable energy systems composing the plant must be optimally designed and operated. Therefore, this paper investigates the challenge of the optimal design and energy management of a grid connected renewable energy plant composed of a solar thermal collector, photovoltaic system, ground source heat pump, battery, one short-term thermal energy storage and one seasonal thermal energy storage. To this aim, this paper develops a methodology based on a genetic algorithm that optimally designs a 100% renewable energy plant with the aim of minimizing the electrical energy taken from the grid. The load profiles of thermal, cooling and electrical energy during a whole year are taken into account for the case study of the Campus of the University of Parma (Italy).
Comparison of Batteries and Pumping Hydro with PaTs as energy storage technologies for a micro-hybrid generation system: Multi-objective optimization through a MILP algorithm
Authors: Alberizzi Jacopo C. , Renzi Massimiliano
Published: February 2021

Small-scale hybrid energy systems are often composed by different power production technologies and adopted in mini-grids. In this work, a Mixed Integer Linear Programming optimization algorithm has been developed to compute the optimal scheduling of a micro-grid constituted by Internal Combustion Generators (ICGs) and a Storage System that can be either a conventional battery storage system or a Pumping Hydro energy Storage (PHES) based on Pump-as-Turbines. The algorithm computes the optimal energy generation scheduling of the micro-grid, minimizing a multi-objective fitness function constituted by the total costs of the energy system and the total CO2 and NOx emissions. In particular, the emissions are modelled with varying trends depending on the ICG load and not with constant values, which represents a simplification that is often adopted but that can induce misleading results. Furthermore, the algorithm takes into account all the physical constraints related to the generators and the storage system, such as maximum and minimum power generation, ramp-up and ramp-down limits and minimum up and down-time. The two energy storage technologies are compared and results show that a management strategy based on this algorithm can reduce significantly the total emissions of the system.
Impact of hydrogen admixture on interacting premixed flames in domestic boilers
Authors: Lamioni Rachele , Cinnirella Sebastiano , Bronzoni Cristiana , Folli Marco , Tognotti Leonardo , Galletti Chiara
Published: February 2021

The injection of hydrogen into the natural gas network can contribute to the large-scale integration of renewables, as hydrogen can be easily produced through electrolysis from wind or solar energy. However, the addition of hydrogen to natural gas influences fuel properties, asking for the assessment of the safe and efficient operation of existing end-user equipment, such as domestic burners and boilers. In this work, 3-dimensional resolved numerical simulations based on Computational Fluid Dynamics are carried out to shed light on the effect of H2 addition on the combustion process occurring in condensing boilers equipped with perforated cylindrical burners. To this purpose, multi-hole geometries emulating a portion of a perforated burner are analyzed. Since the burner holes are positioned very close to each other, the interaction of the adjacent laminar premixed flames is observed to occur with influence on the flow and thermo-chemical fields which differ from those of a single premixed flame. The addition of hydrogen was found to lead to an anticipation of the reaction zone, although the general features observed with the G222 gas (23% H2, 77% CH4 ) were alike those of the G20 gas (100% CH4).
Simulations of a flexible 100 kWel PEM Fuel Cell power plant for the provision of grid balancing services
Authors: Crespi Elena , Guandalini Giulio , Campanari Stefano
Published: February 2021

The continuous growth of non-programmable renewable energy resources penetration leads to unpredictable oscillations of the net load faced by dispatchable power plants, hindering the reliability and stability of the electric grid and requiring additional flexible resources. The EU project GRASSHOPPER focuses on MW-scale Fuel Cell Power Plant (FCPP) based on low temperature PEM technology. The project aims to setup and demonstrate a 100 kWel PEM FCPP, flexible in power output and designed to provide grid support. This work presents a dynamic simulation model of the FCPP, developed to simulate plant flexible operation and identify the best management strategy, aiming at optimizing the efficiency while reducing the degradation rate. Cold start up simulations, according to a warm-up procedure limiting stack degradation, result in a time to operation equal to 26 minutes. A sensitivity analysis is performed to determine which parameters mostly influence the warm-up duration, showing that it is possible to reduce start-up time substantially (e.g. down to 3 minutes with component preheating). On the other hand, simulations at variable load along the entire range of operation (20-100 kWel), according to grid balancing requirements, show that the plant is able to ramp up and down between the minimum to the maximum load in about 40 seconds.
Outlook of future implementation of PEMFC and SOFC onboard cruise ships
Authors: Gianni Marco , Pietra Andrea , Taccani Rodolfo
Published: February 2021

According to third IMO GHG Study shipping is responsible of about 2, 6% of world CO2e (carbon dioxide equivalent) emissions. The dangerous effect on people is increased because emissions are concentrated in coastal areas. IMO and other bodies are engaged in imposing measures to reduce GHG emissions and improve the overall ship’s energy efficiency. There are many technical and operational improvements that can help to reach these goals, but hydrogen and fuel cells remain one of the best candidates to substantially reduce emissions and fuel consumption. This paper gives an outlook of possible fuel cells applications in the marine sector and analyses the potential of Proton Exchange Membrane Fuel Cells (PEMFC) and Solid Oxide Fuel Cells (SOFC) for the on-board installation. The analysis shows the advantages that fuel cells can give in terms of emissions reductions and fuel saving, but also highlights some challenges that designers will face when implementing these technologies on a cruise ship. Both PEMFC and SOFC application in the marine sector suffer of the lack of standards and regulations from IMO and Classification Societies and high acquisition cost. While PEMFC are ready for marine application, SOFC are still in a study phase for on-board implementation. Also, the type of fuel used by these generators and the possibility of heat recovery can influence their application on-board cruise ships.
Analysis of energy systems for poly-generation using optimization modelling: the optimization process strategies and the formalization of an innovative multi-objective optimization model
Authors: Fragiacomo Petronilla , Lucarelli Giuseppe , Florio Gaetano
Published: February 2021

The purpose of this paper is to describe the numerical modelling processes and optimization strategies of energy systems and to formalize an innovative optimization model for poly-generation systems. The model uses a multi-objective optimization approach, by means of three optimization functions: one of an economic nature, one technical and one relating to polluting emissions. The constraint equations of the problem, the boundary conditions and the input values, as well as some dimensionless parameters are described. In addition to a complete approach, the article proposes innovative aspects based on the studies in the literature, both from a technological and economic-regulatory standpoint. For each proposed innovation, an analysis of how this can influence the optimization model is presented and various types of optimization models have been evaluated, depending on the complexity of the physical system and the consequent numeric modelling.
A study on the thermo-optical behaviour of phosphorescent coatings for passive cooling applications
Authors: Kousis Ioannis , Fabiani Claudia , Pisello Anna Laura
Published: February 2021

Climate change intensifies the Urban Heat Islands (UHI) in hundreds of cities around the globe. Even though tests on traditional cool materials have shown promising results in terms of UHI mitigation, novel advanced solutions are deemed necessary for strategically counteracting UHI. Unlike traditional materials, phosphorescent materials can not only reflect incident shortwave radiation but also reemit it back, i.e. the phenomenon of phosphorescence. Even though this unique reflection-reemission mechanism known as effective solar reflectance (ESR), has been widely tested for sustainable lightning applications, its cooling potential has been surprisingly overlooked. Here, we examine, in-lab, and numerically, the thermo-optical properties of several phosphorescent coatings of different colours and we evaluate their effective cooling potential. Results reveal that the phosphorescence mechanism could be effectively optimized for obtaining phosphorescent-based coatings with an improved optical performance and hence substantially mitigate surface overheating in the built environment.
Energy analysis, numerical simulations and intervention proposals for a NZEB industrial building: the “Loccioni Leaf Lab” case study
Authors: Stamponi Ettore , Lattanzi Nicola , Giorgini Francesco , Serpilli Fabio , Montelpare Sergio , Moretti Elisa
Published: February 2021

The object of this paper is the “Loccioni Leaf Lab”, an industrial nZEB connected to a thermal and electric smart grid. Having nZEB buildings connected to a smart grid offers the possibility of maximizing the benefits that can be obtained by optimal regulation of the grid itself, providing excellent economic and energy results. The case study, which hosts offices and workers operating on test benches, features high performance envelope, solar photovoltaic systems, groundwater heat pumps and a hightechnology control and monitoring system. In order to analyse HVAC-related energy consumptions, the building was modelled using DesignBuilder and EnergyPlus software. The annual dynamic simulations for the assessment of building thermal-energy performance were carried out using available monitored weather data (2019). The model was validated according to ASHRAE guidelines, comparing the outputs of the software with data collected and stored by Company internal database. In the validation process, mean indoor air temperatures of several zones and heating and cooling energy consumptions were considered as key outputs. The validated model has then been used to suggest optimization strategies and to analyse the results obtained with proposed interventions in terms of energy saving.
Batch Hydrothermal liquefaction of end-of-life plastic and oil characterization
Authors: Ciuffi Benedetta , Rosi Luca , Miliotti Edoardo , Lotti Giulia , Rizzo Andrea Maria , Chiaramonti David
Published: February 2021

Finding a proper way to manage the enormous amount of waste plastic that is globally produced, is one of the main environmental challenges of our times. Among the different types of chemical recycling, Hydrothermal Liquefaction (HTL) appears as a potential method for the treatment of plastic waste mixes, for sustainable production of biocrude or chemicals with high added value. In this work hydrothermal liquefaction reactions were carried out on a polymeric residue, obtained from an industrial plastic waste collection and recycling process. The residue has a heterogeneous composition consisting not only of polymers but also paper and metals. Two batch experiments were performed in a stainless-steel Parr autoclave at 340 °C, investigating a residence times of 5 hours and the use of an alkaline catalyst (NaOH). The oils obtained from the reactions, as well as the aqueous phases, have been analysed by different analytical techniques such as: FT-IR spectroscopy, GC-MS, GC-FID, IC. The operating conditions used in this work, allowed the degradation of cellulose and polymers with reactive sites for hydrolysis such as PET, nylon and PVAc, while polyolefins (PE, PP) were not attacked. The use of a basic catalyst favoured a greater hydrolysis rate.
Dernières nouvelles du chromosome X
Authors: Moscatelli Madeleine , Rougeulle Claire
Published: February 2021

L’inactivation d’un des deux chromosomes X des femelles mammifères est un processus vital et emblématique des régulations épigénétiques. Elle est déclenchée par l’accumulation d’un ARN non codant, XIST, qui isole le chromosome concerné de la machinerie transcriptionnelle ; l’état inactif persiste ensuite de manière stable au cours des divisions cellulaires successives. Cependant, des découvertes récentes conduisent à revisiter certains principes généraux de l’inactivation du chromosome X initialement établis. Ainsi le chercheur, tout comme le poète, est-il invité à « vingt fois sur le métier remettre son ouvrage ».
Reinventing the oilseeds processing to extract oil while preserving the protein
Authors: Carré Patrick
Published: February 2021

The move towards more sustainable production and consumption patterns is a goal shared by a large part of society. In the oil-mill sector, whether it be animal feed or human food, this development should make it possible to improve the protein autonomy of the territories and to use proteins more efficiently. Current methods make some of the rapeseed proteins indigestible and leave most of the undesirable compounds from the seeds in resulting meals. Residual oil, fibrous envelopes, glucosinolates, phytic acid, phenolic compounds and oligosaccharides, as well as overcooking, however, have negative effects on the value of proteins. An important part of the article is devoted to reviewing these effects. Their extraction, combined with milder heat treatments, would provide excellent quality proteins to the market and generate value for the entire value chain. Efficient dehulling and mechanical extraction would be the prerequisites for this development. An ethanolic extraction revisited to exploit the secondary metabolites would then complete this process with, however, a limited effect on phytic acid. All these technologies have the advantage of not posing major acceptability problems. This development requires new investments in applied research to make this new approach to processing oilseeds possible and efficient.
Einfluss der mediterranen Ernährung auf das Brustkrebsrisiko: Welche Rolle spielt das Mikrobiom?
Authors: Seethaler Benjamin , Beutel Michelle , Basrai Maryam , Kiechle Marion , Bischoff Stephan C.
Published: February 2021

Zahlreiche Studien haben gezeigt, dass die mediterrane Ernährung vor ernährungsmitbedingten Erkrankungen wie Übergewicht, Diabetes mellitus Typ 2, Herz-Kreislauf-Erkrankungen und verschiedenen Krebsentitäten, einschließlich Brustkrebs, schützen kann. Die zugrunde liegenden Mechanismen sind jedoch weitgehend unklar. Bislang wurde vor allem die Rolle antiinflammatorischer Fettsäuren diskutiert. In der vorliegenden Übersichtsarbeit soll am Beispiel des genetisch determinierten sowie des sporadischen Brustkrebses der Frage nachgegangen werden, welche Rolle das Darmmikrobiom spielen könnte, dessen Zusammensetzung und Funktion durch die mediterrane Ernährung verändert wird.
Sportwetten und Suchtgefahren
Authors: Hayer Tobias , Kalke Jens
Published: February 2021

Im Glücksspielbereich nehmen Sportwetten aufgrund ihrer Vielfalt in der
konkreten Ausgestaltung eine Sonderstellung ein. Inzwischen existiert eine breite
Palette an kommerziellen Wettangeboten, die sich deutlich voneinander unterscheiden.
Hierzu zählen in erster Linie das grundsätzliche
Geschäftsmodell (Totalisatorprinzip vs. Buchmacherwette), die
Zugänglichkeit (stationär vs. internetgestützt), die Art der
Sportwette (Festquotenwetten vs. Live-Wetten), die im Fokus stehende Sportart (von
Fußball bis zum sog. „E-Sports“) und das zu
prognostizierende Sportereignis (Endergebnis vs. Teilausschnitt eines sportlichen
Wettbewerbs). In den letzten 20 Jahren hat sich der globale Markt für
Sportwetten stark verändert. Insbesondere wandelten sich Sportwetten von
einem Spielangebot mit diskontinuierlicher Spielabfolge zu einem Produkt mit hoher
Ereignisfrequenz (z. B. Live-Wetten). Zwar stehen auf der einen Seite des breiten
Angebotsspektrums nach wie vor Spielformen wie das Fußballtoto mit einer
Ausspielung pro Woche. Auf der anderen Seite setzen Produkte wie mannigfaltige
Live-Wetten, etwa auf den nächsten Punkt beim Tennis, neue Spielanreize,
indem sie mit Entscheidungen über Gewinn und Verlust im Sekundentakt
locken.
Rationaler Umgang mit akuten Kreuzschmerzen
Authors: Kamp Rainer
Published: February 2021

Das Thema „Rücken“ ist in der täglichen Praxis ein Dauerbrenner. Dabei gibt es eine auffallende Diskrepanz zwischen praktiziertem ärztlichen Handeln und evidenzbasiertem Wissen. Diese kognitive Dissonanz zwischen ärztlichem Wissen und Tun kann nach Ansicht internationaler und nationaler Leitlinien und Autoren zu negativen Folgen für Patienten, Ärzte und das betreffende Gesundheitssystem führen. Ein Schließen dieser Lücke kann als aktiver Beitrag zum Patientenschutz sowie vor Unter- und Überversorgung angesehen werden.
Xylazine or detomidine in dairy calves: a comparison of clinically relevant pharmacodynamic parameters under sedation
Authors: Gittel Claudia , Brehm Walter , Wippern Maike , Roth Susanne , Hillmann Aline , Michaele Alef
Published: February 2021

Objective Chemical restraint in dairy calves is necessary to enable diagnostic and surgical procedures. It is unclear whether xylazine or detomidine differ with regard to desirable and unwanted effects.

Material and methods In a prospective randomized interventional study, 10 healthy Holstein-Friesian calves (age range 3–6 month) were sedated with either xylazine (0.1 mg/kg, Group X, n = 5) or detomidine (0.03 mg/kg, Group D, n = 5) intravenously, followed by butorphanol (0.1 mg/kg i. v.) in all animals. Characteristics of sedation and selected pharmacodynamic parameters were compared between groups using a non-parametric Mann-Whitney U test.

Results All calves (5/5) in Group X and (3/5) calves in Group D became laterally recumbent within 5 minutes. Two calves (40 %) in Group D remained standing and could not been positioned in lateral recumbency 15 minutes after initial administration of the sedation agents. Sedation scores, onset and duration of sedation did not differ between groups. Heart and respiratory rate decreased in both groups. Mean arterial pressure was with around 30 mmHg significantly higher in Group D (t25, t30, t35, t40 with p = 0.018, 0.036, 0.029 and 0.016, respectively). In Group X, glucose level (t60) and packed cell volume (t30) were significantly lower (p = 0.032 and 0.048, respectively).

Conclusion and clinical relevance The xylazine-butorphanol combination provided reliable recumbent chemical restraint. With detomidine-butorphanol recumbency failed in some individuals, but a sufficient clinical sedation was achieved. Based on the limited monitoring used in this study, the side effects are of minor clinical relevance in healthy individuals.
Beziehungen zwischen Managementfaktoren und Bestandsstatus bezüglich Infektion mit dem Virus des Porzinen Reproduktiven und Respiratorischen Syndroms
Authors: David Karina , Vergara Helga , Eger Sabine , Klassen Anne , Schwödiauer Philipp , Reiner Gerald , Donat Karsten
Published: February 2021

Gegenstand und Ziel In Sachsen und Thüringen, beides Bundesländer mit einer geringen Dichte kommerzieller Schweinehaltungen, wird im Rahmen eines freiwilligen Bekämpfungsprogramms eine Sanierung schweinehaltender Betriebe von der Infektion mit dem Virus des Porzinen Reproduktiven und Respiratorischen Syndroms (PRRSV) angestrebt. In einem Teil der Betriebe verlief diese bereits erfolgreich. Ziel dieser Studie war, Managementfaktoren zu identifizieren, die mit einem positiven bzw. negativen Status bezüglich des Nachweises von PRRSV-Antikörpern (AK-Status) oder PRRSV-Genom (PCR-Status) auf Herdenebene in Beziehung stehen.

Material und Methoden Die Datenerhebung erfolgte in 82 Betrieben einer sich in Sanierung befindlichen Region. Befunde von Untersuchungen der Jahre 2011 bis 2018 wurden jahresweise zusammengefasst und zu den abgefragten Parametern in Zusammenhang gesetzt. Ein generalisiertes lineares gemischtes Modell wurde verwendet, um mit dem AK- und PCR-Status assoziierte Faktoren zu identifizieren.

Ergebnisse Eine negative Beziehung zum PCR-Status bestand zu den Variablen „Schwarz-Weiß-Trennung auf der Laderampe“ (p = 0,012), „Trennung von Jungsauen und Sauen“ (p = 0,017) sowie „Führen eines Besucherbuchs“ (p = 0,046). Dagegen waren die Variablen „Trennung von Jungsauen und Masttieren“ (p = 0,044) und „getrennte Treibwege“ (p = 0,042) positiv mit dem PCR-Status assoziiert. Die Durchführung einer PRRSV-Impfung stand in positiver Beziehung mit dem AK- und dem PCR-Status der Betriebe (p = 0,005 bzw. 0,001). Innerhalb zahlreicher Variablen wurde eine geringe Variabilität beobachtet.

Schlussfolgerung Bestimmte Biosicherheitsmaßnahmen zur Regulierung des Tierverkehrs (Schwarz-Weiß-Trennung auf der Laderampe) oder Personenverkehrs (Besucherbuch) sowie das Management der Jungsauen tragen zu einer Reduktion von PRRSV-Infektionen und damit zu einem negativen Bestandsstatus bei.

Klinische Relevanz Durch eine Kombination verschiedener Maßnahmen kann die Ausbreitung von PRRSV in Schweinebeständen reduziert werden. Schwerpunkt ist dabei die Unterbrechung von Infektionsketten bei den Jungsauen, entweder durch eine von Altsauen separierte Eingliederung oder Immunisierung, wozu möglicherweise auch eine gemeinsame Haltung mit Mastschweinen beitragen kann.