bluuebunny/crossref_metadata_2025 huggingface dataset:
Understanding the Impact of COVID-19 on Physician Moms
Authors: Pearson Claire , Levine Miriam , Messman Anne , Chopra Teena , Awali Reda , Robb Lauren , Melikian Ryan , Janis Andrea , Levine Diane L.
Published: February 2021

Objective:

This study evaluates the personal and professional experiences of physician mothers during the coronavirus disease 2019 (COVID-19) pandemic and the impact of the pandemic on the lives of physician mothers.

Methods:

Using social media to reach a broad range of physicians, a convenience sample of physician mothers completed an on-line survey posted between April 27 and May 11. Members were encouraged to repost on social media and share with personal contacts resulting in a passive snowball sampling effect.

Results:

A total of 2709 physician mothers from 48 states, Puerto Rico, and 19 countries representing more than 25 medical specialties completed the survey. Most were between 30 and 39 y of age, 67% self-identified as white, 17% as Asian, 4% as African American. Most had been working for 11-16 y. A total of 91% had a spouse/partner of the opposite sex. Over half were practicing in an area they identified as high COVID-19 density, while 50% had personally cared for a person with COVID-19. Physician mothers were most concerned about exposing their children to COVID-19 and about the morale and safety of their staff.

Conclusions:

This is one of the first studies to explore the personal and professional challenges facing physician mothers during a pandemic. Physician mothers were most concerned about exposing their families to COVID-19. Mothers continued to work and at times increased their work, despite having domestic, childcare, and schooling responsibilities.
1,050 years of Hurricane Strikes on Long Island in The Bahamas
Authors: Wallace E. J. , Donnelly J. P. , van Hengstum P. J. , Winkler T. S. , McKeon K. , MacDonald D. , d'Entremont N. E. , Sullivan R. M. , Woodruff J. D. , Hawkes A. D. , Maio C.
Published: February 2021

Sedimentary records of past hurricane activity indicate centennial‐scale periods over the past millennium with elevated hurricane activity. The search for the underlying mechanism behind these active hurricane periods is confounded by regional variations in their timing. Here, we present a new high resolution paleohurricane record from The Bahamas with a synthesis of published North Atlantic records over the past millennium. We reconstruct hurricane strikes over the past 1,050 years in sediment cores from a blue hole on Long Island in The Bahamas. Coarse‐grained deposits in these cores date to the close passage of seven hurricanes over the historical interval. We find that the intensity and angle of approach of these historical storms plays an important role in inducing storm surge near the site. Our new record indicates four active hurricane periods on Long Island that conflict with published records on neighboring islands (Andros and Abaco Island). We demonstrate these three islands do not sample the same storms despite their proximity, and we compile these reconstructions together to create the first regional compilation of annually resolved paleohurricane records in The Bahamas. Integrating our Bahamian compilation with compiled records from the U.S. coastline indicates basin‐wide increased storminess during the Medieval Warm Period. Afterward, the hurricane patterns in our Bahamian compilation match those reconstructed along the U.S. East Coast but not in the northeastern Gulf of Mexico. This disconnect may result from shifts in local environmental conditions in the North Atlantic or shifts in hurricane populations from straight‐moving to recurving storms over the past millennium.
Modelling safe protocols for reopening schools during the COVID-19 pandemic in France
Authors: Di Domenico Laura , Pullano Giulia , Sabbatini Chiara E. , Boëlle Pierre-Yves , Colizza Vittoria
Published: February 2021

As countries in Europe implement strategies to control the COVID-19 pandemic, different options are chosen regarding schools. Through a stochastic age-structured transmission model calibrated to the observed epidemic in Île-de-France in the first wave, we explored scenarios of partial, progressive, or full school reopening. Given the uncertainty on children’s role, we found that reopening schools after lockdown may increase COVID-19 cases, yet protocols exist to keep the epidemic controlled. Under a scenario with stable epidemic activity if schools were closed, reopening pre-schools and primary schools would lead to up to 76% [67, 84]% occupation of ICU beds if no other school level reopened, or if middle and high schools reopened later. Immediately reopening all school levels may overwhelm the ICU system. Priority should be given to pre- and primary schools allowing younger children to resume learning and development, whereas full attendance in middle and high schools is not recommended for stable or increasing epidemic activity. Large-scale test and trace is required to keep the epidemic under control. Ex-post assessment shows that progressive reopening of schools, limited attendance, and strong adoption of preventive measures contributed to a decreasing epidemic after lifting the first lockdown.
Graphene-based materials: the key for the successful application of pHEMA as a blood-contacting device
Authors: Pereira Andreia T. , Henriques Patrícia C. , Schneider Karl H. , Pires Ana L. , Pereira André M. , Martins Maria Cristina L. , Magalhães Fernão D. , Bergmeister Helga , Gonçalves Inês C.
Published: February 2021

Incorporation of oxidized graphene improves pHEMA's mechanical properties enabling its application as bulk material in the design of blood-contacting devices. These composites keep pHEMA's biological properties, preventing thrombosis and infection.
Constructing an unprecedented {MnII38} matryoshka doll with a [Mn18(CO3)9] inorganic core and magnetocaloric effect
Authors: Wu Tai-Xue , Tao Ye , He Qiu-Ju , Li Hai-Ye , Bian He-Dong , Huang Fu-Ping
Published: February 2021

An unprecedented [Mn18(CO3)9] inorganic core and [Mn20] metal–organic periphery composed the largest homometallic single-valence {MnII38} aggregate with a four-shells matryoshka doll that displays a significant magnetocaloric effect (MCE).
A continuous flow synthesis of [1.1.1]propellane and bicyclo[1.1.1]pentane derivatives
Authors: Donnelly Kian , Baumann Marcus
Published: February 2021

A powerful flow process is presented realising the on-demand preparation of [1.1.1]propellane which is subsequently exploited towards generating drug-like BCP-derivatives.
Carbonyl-enriched hierarchical carbon synergizes redox electrolyte for highly-efficient and stable supercapacitors
Authors: Rafiq Muhammad Imran , Wang Xinlei , Farid Tanveer , Zhou Jie , Tang Jian , Tang Weihua
Published: February 2021

Carbonyl-enriched carbon hierarchical hybrid was developed to promote redox reaction with cupric chloride. Ultrahigh area specific capacitance of 13.1 F cm−2 (30 mA cm−2) is demonstrated with over 99.6% retention after 45 000 cycling in supercapacitors.
Salt or/and cocrystal? The case of the antidepressant drug venlafaxine
Authors: Yu Hongmei , Zhang Yong , Zhang Baoxi , Wang Ying , Zhang Li , Zhang Hailu , Gong Ningbo , Lu Yang , Du Guanhua
Published: February 2021

The VLF–DA (1 : 2) salt cocrystal exhibited distinctively different properties in terms of kinetic stability, solubility, and bioavailability from the VLF–DA (1 : 1) salt.
The primary photo-dissociation dynamics of lactate in aqueous solution: decarboxylation prevents dehydroxylation
Authors: Thøgersen Jan , Vaida Veronica , Bregnhøj Mikkel , Weidner Tobias , Jensen Frank
Published: February 2021

We study the primary photolysis dynamics of aqueous lactate induced by photo-excitation at λ = 200 nm.
Efficiency analysis of helium-cooled MAS DNP: case studies of surface-modified nanoparticles and homogeneous small-molecule solutions
Authors: Matsuki Yoh , Kobayashi Takeshi , Fukazawa Jun , Perras Frédéric A. , Pruski Marek , Fujiwara Toshimichi
Published: February 2021

DNP enhancement, paramagnet-induced quenching/depolarization and build-up times are studied in a heterogeneous catalyst between 30 and 100 K. He-cooled MAS DNP at 30 K provides up to 100-fold better time performance than N2-cooled MAS DNP at 90 K.
Advancing photoreforming of organics: highlights on photocatalyst and system designs for selective oxidation reactions
Authors: Toe Cui Ying , Tsounis Constantine , Zhang Jiajun , Masood Hassan , Gunawan Denny , Scott Jason , Amal Rose
Published: February 2021

This review appraises recent literature and provides guidelines for the rational design of photocatalytic system for selective photoreforming reaction.
Addition of granular activated carbon during anaerobic oleate degradation overcomes inhibition and promotes methanogenic activity
Authors: Tan Lea Chua , Lens Piet N. L.
Published: February 2021

Simply adding granular activated carbon (GAC) in an anaerobic digestor treating lipid-rich wastewater can improve acidogenesis and methanogenesis by more than 10 times compared to the control without GAC.
Efficient extracellular laccase secretionviabio-designed secretory apparatuses to enhance bacterial utilization of recalcitrant lignin
Authors: Cao Lanfang , Lin Lu , Sui Haiyan , Wang Heng , Zhang Zhichao , Jiao Nianzhi , Zhou Jizhong
Published: February 2021

Our study advances the knowledge of secretion mechanisms in Gram-negative bacteria and provides novel insights into the lignin utilization by extracellular lignolytic enzyme-bacterial cell systems.
Critical assessment of reaction pathways for conversion of agricultural waste biomass into formic acid
Authors: Shen Feng , Smith Jr. Richard Lee , Li Jialu , Guo Haixin , Zhang Xiao , Qi Xinhua
Published: February 2021

Reaction pathways for conversion of agricultural waste biomass into formic acid are reviewed for established (fast pyrolysis, acid hydrolysis, wet oxidation, catalytic oxidation), and cutting-edge (photocatalysis, electrocatalysis) methods.
One-step chromatographic purification of K, Ca, and Sr from geological samples for high precision stable and radiogenic isotope analysis by MC-ICP-MS
Authors: Li Xiaoqiang , Han Guilin
Published: February 2021

This study presents a method for one-step chromatographic separation of K–Ca–Sr from matrix elements, and the purification procedure is based on AG50W-X12 cation exchange resin without any intervening evaporation step.
A polymeric bis(di-p-anisylamino)fluorene hole-transport material for stable n-i-p perovskite solar cells
Authors: Tremblay Marie-Hélène , Schutt Kelly , Zhang Yadong , Barlow Stephen , Snaith Henry J. , Marder Seth R.
Published: February 2021

Half-devices made with a norbornene homopolymer with hole-transporting 2,7-bis(di-p-anisylamino)fluorene side chains exhibit improved light and heat stability in comparison to those incorporating spiro-OMeTAD.
Exploring alkaline routes for production of TEOS-based consolidants for carbonate stones using amine catalysts
Authors: Rodrigues Alexandra , Sena da Fonseca Bruno , Ferreira Pinto Ana Paula , Piçarra Susana , Montemor M. Fátima
Published: February 2021

TEOS-based sols following basic catalysis routes were explored and showed high potential and important advantages for consolidation of soft limestone.
Fabrication of a wide temperature Mn–Ce/TNU-9 catalyst with superior NH3-SCR activity and strong SO2and H2O tolerance
Authors: Ji Shuai , Li Zhifang , Song Kun , Li Hairui , Li Yueyu , Yang Jian , Li Mingjie , Yang Chonglong
Published: February 2021

A Mn–Ce/TNU-9 catalyst demonstrated excellent sulfur and water resistance and good catalytic stability in the NH3-SCR reaction.
An electrically driven whispering gallery polariton microlaser
Authors: Jiang Mingming , Wan Peng , Tang Kai , Liu Maosheng , Kan Caixia
Published: February 2021

An electrically driven whispering gallery polariton microlaser composed of a ZnO:Ga microwire and a p-GaAs template was fabricated. Its working characteristics of polariton lasing in the near-infrared spectrum were demonstrated.
Self-assembly of colloidal nanoparticles into 2D arrays at water–oil interfaces: rational construction of stable SERS substrates with accessible enhancing surfaces and tailored plasmonic response
Authors: Ye Ziwei , Li Chunchun , Chen Qinglu , Xu Yikai , Bell Steven E. J.
Published: February 2021

Nanoparticle self-assembly at water–oil interfaces has emerged as a convenient and efficient method to construct stable, active and reproducible plasmonic substrates for SERS. In this review we summarize the progress that has been made in this field.
Ni, beyond thermodynamic tuning, maintains the catalytic activity of V species in Ni3(VO4)2 doped MgH2
Authors: Zang Jiahe , Wang Shaofei , Hu Rongrun , Man Han , Zhang Jichao , Wang Fei , Sun Dalin , Song Yun , Fang Fang
Published: February 2021

A bimetallic oxide Ni3(VO4)2 has been synthesized to catalyze the hydrogen storage reaction of MgH2. The formation of the Mg2Ni alloy and the kinetic modulation of V results in a dehydrogenation temperature of 210 °C. The NiV2O4 intermediate active species is also detected.
Coconut-shell-derived activated carbon for NIR photo-activated synergistic photothermal-chemodynamic cancer therapy
Authors: Wu Gang , Jiang Bao , Zhou Lin , Wang Ao , Wei Shaohua
Published: February 2021

Activated carbon nanoparticles (ANs) were synthesized from coconut shell. ANs show peroxidase and photothermal conversion activities, allowing synergistic cancer treatment via chemodynamic therapy (CDT) and photothermal therapy (PTT).
Enhancement of osteoporotic bone regeneration by strontium-substituted 45S5 bioglassviatime-dependent modulation of autophagy and the Akt/mTOR signaling pathway
Authors: Zhang Xinran , Cui Jinjie , Cheng Liming , Lin Kaili
Published: February 2021

Strontium (Sr) promotes osteogenic differentiation and osteoporotic bone regenerationviatime-dependent modulation of autophagy and the Akt/mTOR signaling pathway.
Inverted organic photovoltaics with a solution-processed ZnO/MgO electron transport bilayer
Authors: Ierides Ioannis , Squires Isaac , Lucarelli Giulia , Brown Thomas M. , Cacialli Franco
Published: February 2021

Applying ultrathin MgO as the top component of a ZnO/MgO electron transport layer enhances the performance of organic photovoltaics.
Facile access to multi-state redox-active, push–pull naphthalenediimides: panchromatic radical anions and supramolecular networks
Authors: Bansal Deepak , Mukhopadhyay Pritam
Published: February 2021

A facile one-pot synthetic route, which apples DMF as a reagent is reported to access core-modified D–π–A naphthalenediimides (NDIs) with multi-state redox properties and well-defined supramolecular networks.
Deep red SrLaGa3O7:Mn4+ for near ultraviolet excitation of white light LEDs
Authors: Liu Quan , Xiong Puxian , Liu Xiaoqi , Fu Yubin , Wu Sheng , Dong Quan , Li Yuanyuan , Chen Yan , Ma Zhijun , Peng Mingying
Published: February 2021

Red luminescent phosphor SrLaGa3O7:Mn4+ was prepared by the traditional high-temperature solid-state reaction.
Probing nucleus-enriched proteins in single living cells via a subcellular-resolved plasmonic immunosandwich assay
Authors: Liu Jia , Xie Dan , Liu Zhen
Published: February 2021

Specific extraction and ultrasensitive detection of low-copy-number nuclear proteins in single living cells were achieved via a subcellular-resolved plasmonic immunosandwich assay.
A highly sensitive electrochemical microRNA-21 biosensor based on intercalating methylene blue signal amplification and a highly dispersed gold nanoparticles/graphene/polypyrrole composite
Authors: Pothipor Chammari , Aroonyadet Noppadol , Bamrungsap Suwussa , Jakmunee Jaroon , Ounnunkad Kontad
Published: February 2021

An ultrasensitive electrochemical biosensor based on a gold nanoparticles/graphene/polypyrrole composite modified electrode and a signal amplification strategy employing methylene blue is developed as a potential tool for the detection of miRNA-21.
Tailoring the triplet level of isomorphic Eu/Tb mixed MOFs for sensitive temperature sensing
Authors: Xia Tifeng , Shao Zhengfeng , Yan Xiayan , Liu Meng , Yu Libing , Wan Yating , Chang Dingyue , Zhang Jun , Zhao Dian
Published: February 2021

Different thermo-responsive fluorescence thermometers were obtained by regulating the triplet energy level of organic ligands within isostructural Eu/Tb mixed MOFs.
Growth mechanism of the spherulitic propylthiouracil–kaempferol cocrystal: new perspectives into surface nucleation
Authors: Xiao Yuntian , Yang Wenchao , Zhou Ling , Hao Hongxun , Bao Ying , Yin Qiuxiang , Xie Chuang
Published: February 2021

A growth mechanism of spherulitic cocrystals shows three stages of single crystal growth, non-crystallographic branching and surface nucleation. Low supersaturation forms loose spherulites, and high temperature causes “spherulites on spherulites”.
A triple-layered PPy@NiCo LDH/FeCo2O4 hybrid crystalline structure with high electron conductivity and abundant interfaces for supercapacitors and oxygen evolution
Authors: He Jing , Hu Zhufeng , Deng Kuan , Zhao Renjun , Lv Xingbin , Tian Wen , Zhang Yu Xin , Ji Junyi
Published: February 2021

A PPy@NiCo LDH/FeCo2O4 triple-layer hybrid with bi-continuous conductive networks is fabricated via a novel one-step hydrothermal reaction and in situ polymerization.
Cost and energy intensity of U.S. potable water reuse systems
Authors: Sim Alison , Mauter Meagan S.
Published: February 2021

We present a dataset of 70 operating, demonstration, pilot and unbuilt U.S. potable water reuse systems and report on treatment train designs, costs, estimated electricity intensity, and air emission externalities.
A synergetic effect between photogenerated carriers and photothermally enhanced electrochemical urea-assisted hydrogen generation on the Ni-NiO/Nickel Foam catalyst
Authors: Wang Qi , Cheng Xing , Sun Yukun , Sun Zaicheng , Wang Dong , Chen Ge , Schaaf Peter
Published: February 2021

Both photogenerated carrier and photothermal effect enhanced electrochemical urea-assisted hydrogen generation on a Ni-NiO/Nickel Foam catalyst.
The preparation of novel triphenylamine-based AIE-effect fluorescent probe for selectively detecting mercury(ii) ion in aqueous solution
Authors: Liu Lian , Ma Jie , Pan Jiamin , Li Denghui , Wang Huiling , Yang Honggao
Published: February 2021

A novel triphenylamine-based TPA-ME exhibits good AIE fluorescence in a DMF/Water system and excellent probe property for detecting Hg2+ in solution.
Plasmon-enhanced unidirectional charge transfer for efficient solar water oxidation
Authors: Li Chuanping , Li Shuoren , Xu Chen , Ma Kongshuo
Published: February 2021

Plasmon-enhanced unidirectional charge transfer channels are fabricated and employed as photoanodes for efficient solar water oxidation.
Solar cell contacts: quantifying the impact of interfacial layers on selectivity, recombination, charge transfer, and Voc
Authors: Egelhofer Ruegger Kira E. , Roe Ellis T. , Lonergan Mark C.
Published: February 2021

A three-in-one solar cell is used to quantify how an interfacial layer modifies electron/hole collection, recombination, and photovoltaic performance.
A deep-dyeing strategy for ultra-stable, brightly luminescent perovskite-polymer composites
Authors: Zhang Caicai , He Ziqian , Mogensen Mirra , Gesquiere Andre J. , Chen Chia-Hsun , Chiu Tien-Lung , Lee Jiun-Haw , Wu Shin-Tson , Dong Yajie
Published: February 2021

A deep-dyeing strategy that can convert commercial PET polymers into luminescent perovskite-polymer composites is demonstrated. Such composites show excellent color tunability, saturated colors, high efficiency and superior environmental stability.
Mechanisms for collective inversion-symmetry breaking in dabconium perovskite ferroelectrics
Authors: Allen Dominic J. W. , Bristowe Nicholas C. , Goodwin Andrew L. , Yeung Hamish H.-M.
Published: February 2021

We show that the combination of molecular shape and strain coupling drives the emergence of polarisation in methyldabconium perovskite ferroelectrics.
Model predictive control with fixed weighting factor for three‐phase four‐switch inverter‐fed PMSM drives considering capacitor voltage offset suppression
Authors: Hang Jun , Zhang Jibo , Wu Han , Ding Shichuan
Published: February 2021

This study proposes a model predictive control (MPC) method with a fixed weighting factor for three‐phase four‐switch inverter‐fed permanent magnet synchronous motor drives to suppress the capacitor voltage offset. The prediction model of the capacitor voltage difference is obtained based on the relationship between capacitor voltage and phase current. Then by analysing the relationship between basic voltage vector, electromagnetic torque and flux amplitude, the control of electromagnetic torque and flux in the model predictive torque control is transformed into the control of the voltage vector. The dimension of the capacitor voltage difference is the same as that of the voltage vector, hence the cost function with the fixed weighting factor is defined with the consideration of the capacitor voltage offset suppression. The effectiveness of the proposed MPC method is validated by the simulation and experiment.
Water level monitoring using classification techniques on Landsat‐8 data at Sangam region, Prayagraj, India
Authors: Mishra Vikash K. , Pant Triloki
Published: February 2021

In the present study, Landsat‐8 data have been used for water identification at the Sangam region, the confluence of the Ganges and Yamuna rivers. Since the water of both the rivers varies in characteristics, it is necessary to explore the most appropriate band of Landsat‐8 imagery for the identification of water bodies. Accordingly, a two folded study has been performed, viz., the selection of a suitable band to identify water bodies and to monitor the water level at the Sangam region from 2013 to 2018. It is observed in the study that band‐7 is the most suitable band for water identification, which is used for the classification and monitoring of water. The classification results are highly significant as the overall accuracy ranges between 95.49 and 100%. The monitoring of water level is done based on classification results for mapping the area of water in real units which can be useful for the prediction of flood situations. The achievement of the present study is the mapping of water area in real units with the help of image pixels which is one of the prominent applications of image processing in earth sciences.
Model predictive control optimisation using the metaheuristic optimisation for blood pressure control
Authors: Ahmadpour Mohammad Reza , Ghadiri Hamid , Hajian Saeed Reza
Published: February 2021

Given the importance of high blood pressure, it is important to control and maintain a constant blood pressure level in the normal state. The main aim of this article is to design a model predictive controller with a genetic algorithm (GA) for the regulation of arterial blood pressure. The present study is an applied cross‐sectional study. In order to do this research, studies related to designing mathematical models for blood pressure regulation and mechanical models for heart muscle and pressure sensors are investigated. Then, a model predictive controller with GA is designed for blood pressure control. All control and design operations are performed in the MATLAB software. According to the viscoelasticity of blood, transducer, and injection set, we can assume the mechanical model as Mass, Spring, and Damper. Initially, the patient's blood pressure is lower than normal, and after controlling, the patient's blood pressure returned to normal. By using a GA‐based model predictive control (MPC), mathematical validation, and mechanical model, the patient's blood pressure can be adjusted and maintained. The simulation result shows that the GA‐based MPC offers acceptable response and speed of operation and the proposed controller can achieve good tracking and disturbance rejection.
Transition region adaptive conduction (TRAC) in multidimensional magnetohydrodynamic simulations
Authors: Zhou Yu-Hao , Ruan Wen-Zhi , Xia Chun , Keppens Rony
Published: February 2021

Context. In solar physics, a severe numerical challenge for modern simulations is properly representing a transition region between the million-degree hot corona and a much cooler plasma of about 10 000 K (e.g., the upper chromosphere or a prominence). In previous 1D hydrodynamic simulations, the transition region adaptive conduction (TRAC) method has been proven to capture aspects better that are related to mass evaporation and energy exchange.

Aims. We aim to extend this method to fully multidimensional magnetohydrodynamic (MHD) settings, as required for any realistic application in the solar atmosphere. Because modern MHD simulation tools efficiently exploit parallel supercomputers and can handle automated grid refinement, we design strategies for any-dimensional block grid-adaptive MHD simulations.

Methods. We propose two different strategies and demonstrate their working with our open-source MPI-AMRVAC code. We benchmark both strategies on 2D prominence formation based on the evaporation–condensation scenario, where chromospheric plasma is evaporated through the transition region and then is collected and ultimately condenses in the corona.

Results. A field-line-based TRACL method and a block-based TRACB method are introduced and compared in block grid-adaptive 2D MHD simulations. Both methods yield similar results and are shown to satisfactorily correct the underestimated chromospheric evaporation, which comes from a poor spatial resolution in the transition region.

Conclusions. Because fully resolving the transition region in multidimensional MHD settings is virtually impossible, TRACB or TRACL methods will be needed in any 2D or 3D simulations involving transition region physics.
Early effects of the COVID-19 outbreak on the African dairy industry: Cases of Burkina Faso, Kenya, Madagascar, and Senegal
Authors: Vall Eric , Mburu John , Ndambi Asaah , Sall Cheikh , Camara Astou Diaw , Sow Anna , Ba Koki , Corniaux Christian , Diaw Arona , Seck Djibril , Vigne Mathieu , Audouin Sarah , Rakotomalala Lovaniaina Jean Elisée , Rakotonoely Lynah Nirina , Ferreira Flavio Dias , Véromalalanirina Erica , Rajaonera Mahery , Ouédraogo Souleymane , Sodré Etienne , Tall Idrissa , Ilboudo Madeleine Diallo , Duteurtre Guillaume
Published: February 2021

This paper provides an early assessment of the effects of the COVID-19 outbreak and of subsequent response measures on milk production, collection, processing, marketing and consumption in Africa. We focus on the period surrounding the first wave of the outbreak (from February to June 2020), during which the number of cases surged and many steps were taken to curb the epidemic. The paper is based on reports from four countries covered by the Africa-Milk Research Project: Burkina Faso, Kenya, Madagascar and Senegal. Data was collected primarily from nine dairy processors located in those countries. Major conclusions of the study are: (1) Dairy farmers were negatively affected by COVID-19 measures when the health crisis coincided with the peak of the milk production season, and when governments did not take steps to support milk production. (2) Small and informal milk collectors were also affected by traffic restrictions as they could not obtain traffic permits. (3) Milk powder importation remained unaffected during the outbreak. (4) Dairy processors (particularly small ones) faced many challenges restricting their operation. Travel restrictions led to temporary interruptions of milk supply, and because of employee protection and safety measures, processing costs increased. (5) Many small retailers were affected by bans on public transport and reduced their purchases of artisanal dairy products; meanwhile, spoilage of dairy products increased during long curfews coupled with poor storage conditions. Supermarkets were able to increase their market share during the pandemic thanks to their connections with industrial dairy processors and wholesalers. (6) A majority of consumers decreased their consumption of dairy products due to a decrease of purchasing power. In some cases, an increase in consumption occurred (due to Ramadan month and dry season high temperatures) and consumption shifted towards long-life dairy products. (7) Overall, the consequences of the health crisis affected more small and informal dairy supply chains than the larger ones, which are more formal, better organised and finally more resilient to face this kind of global crisis.
Compréhension du microclimat urbain lyonnais par l’intégration de prédicteurs complémentaires à différentes échelles dans des modèles de régression
Authors: Alonso Lucille , Renard Florent
Published: February 2021

Le changement climatique est un phénomène majeur actuel générant de multiples conséquences. En milieu urbain, il exacerbe celui de l’îlot de chaleur urbain. Ces deux manifestations climatiques engendrent des conséquences sur la santé des habitants et sur la sensation d’inconfort thermique ressenti en milieu urbain. Ainsi, il est nécessaire d’estimer au mieux la température de l’air en tout point d’un territoire, notamment face à la rationalisation actuelle du réseau de stations météorologiques fixes de Météo France. La connaissance spatialisée de la température de l’air est de plus en plus demandée pour alimenter des modèles quantitatifs liés à un large éventail de domaines, tels que l’hydrologie, l’écologie ou les études sur les changements climatiques. Cette étude se propose ainsi de modéliser la température de l’air, mesurée durant 4 campagnes mobiles réalisées durant les mois d’été, entre 2016 et 2019, dans Lyon par temps clair, à l’aide de modèle de régressions à partir de 33 variables explicatives issues de données traditionnellement utilisées, de données issues de la télédétection par une acquisition LiDAR (Light Detection And Ranging) ou satellitaire Landsat 8. Trois types de régression statistique ont été expérimentés, la régression partial least square, la régression linéaire multiple et enfin, une méthode de machine learning, la forêt aléatoire de classification et de régression. Par exemple, pour la journée du 30 août 2016, la régression linéaire multiple a expliqué 89% de la variance pour les journées d’étude, avec un RMSE moyen de seulement 0,23°C. Des variables comme la température de surface, le NDVI ou encore le MNDWI impactent fortement le modèle d’estimation.
Représentativité des températures mesurées dans la station météorologique Paris-Montsouris
Authors: Dahech Salem , Charfi Sami , Madelin Malika
Published: February 2021

Cette étude s’intéresse à la représentativité des températures mesurées par la station météorologique de Paris-Montsouris; elle montre que le site a un effet remarquable. En effet, l’ombre créée par les arbres situés à proximité des capteurs induit une baisse de la température avoisinant 2°C en moyenne durant l’été, entre 13 h et 18 h TU, par rapport aux stations d’Orly et de Vélizy, situées en milieu dégagé. La rugosité en ville ralentit la vitesse du vent de 1,5 m/s et engendre une baisse de l’humidité entre 16 h et 19 h TU. La campagne de mesure itinérante nocturne, réalisée la nuit du 29 au 30 juin 2019 entre 23 h et 1 h TU, par temps caniculaire, montre que le parc est en moyenne 4°C plus frais que le centre de Paris et que l’intensité de l’îlot de chaleur urbain (ICU) atteint environ 11°C vers 1 h TU du matin. La partie topographiquement surélevée du parc Montsouris est plus chaude d’environ 2°C que celle vallonnée vers 00 h TU.
Exergy and Exergo-Environmental analysis of an ORC for a geothermal application
Authors: Fiaschi Daniele , Manfrida Giampaolo , Mendecka Barbara , Shamoushaki Moein , Talluri Lorenzo
Published: February 2021

Emissions of contaminants and CO2 are becoming a relevant issue for the development of geothermal energy projects. Organic Rankine (ORC) Cycles present in this light particular appeal in the light of the possibility of total reinjection of the geothermal fluid resource including Non-Condensable Gases (NCGs). The Castelnuovo (IT) case study conditions are considered a saturated vapour resource at 10 bar pressure. The performance of the ORC cycle for power generation from this geothermal resource is evaluated through mass and energy balances, stepping up to exergy, Life Cycle Analysis (LCA) and Exergo-Environmental analyses (EEvA). The applied methodology allows to identify the most critical components of the system and to evaluate the environmental indicators of the system.
Development of an experimental test rig for the pyrolysis of plastic residues and waste tires
Authors: Milani Massimo , Montorsi Luca , Storchi Gabriele , Venturelli Matteo , Pirola Carlo , Falletta Ermelinda
Published: February 2021

The paper presents the design of the experimental apparatus developed in order to analyse the performance of a prototype of a pyrolysis system for the exploitation of the plastic residues of industrial processes and the end of life tires. The small scale pilot prototype is specifically designed for carrying out an experimental campaign aimed at determining the influence of different plastic types on the yield and on the quality of the liquid oil, gas and char obtained in the pyrolysis process. The study investigates the effect of different mixture of various plastic products mainly made of polyethylene, styrene butadiene rubber, nylon and natural rubber. The prototype is equipped with a control system able to monitor the main operating parameters of the process, such as the pyrogas pressure and temperature as well as the temperature inside the reactor where the pyrolysis takes place. The monitored variables are employed for deriving correlations among the operating conditions and the yield of the pyrolysis process. Therefore, further analysis concerns experimental measurements in order to estimate the main compounds that are contained in the syngas in comparison to the different plastic wastes analysed. Finally, the emissions of the small-scale prototype are evaluated.
Design of a scaling reduction system for geothermal applications
Authors: Taddei Pardelli Paolo , Tempesti Claretta , Mannelli Andrea , Kravos Albert , Sabard Alex , Fanicchia Francesco , Paul Shiladitya , Şengun Raziye , Sahiller Hakan Alp , Halaçoğlu Ural , Pekdüz Ismail , Stefansson Andri , Galeczka Iwona M.
Published: February 2021

The aim of the EU 2020 GeoSmart project relies on the demonstration of innovative solutions to improve the flexibility and the efficiency of geothermal heat and power systems. This specific study focuses on issues related to silica scaling and its deposition on the reinjection wells. A limiting constraint for geothermal plants to fully utilize the thermal energy form well fluids is in fact the need to reinject geothermal brine at a high enough temperature to prevent thermodynamic fouling by silica scale deposition. GeoSmart aims to develop a solution based on retention system technology to control and reduce the silica scale formation before re-injection. Lowering reinjection temperature would strongly increase plant efficiency by providing extra useful heat. Based on silica scaling numerical simulation, the effects of parameters like pH, temperature and brine composition on silica polymerization and scaling deposition rates, the design and optimization of the retention system has been developed. The design aims to promote polymerization phenomena inside the tank so that scaling is consequently inhibited in the reinjection well pipes. Chemical additives and specific coatings have also been evaluated to guarantee the optimal required conditions. The case study is based on real-data referred to operational conditions and brine composition of the Zorlu Kizildere plant in Turkey. The economic and environmental impact of the retention system has been evaluated with positive outcomes. The in-site test and validation at industrial level of the above mentioned technology will be provided during the next activities of the GeoSmart project
Stochastic operation of isolated microgrids: aggregating-rule-based optimization versus standard approaches
Authors: Fioriti Davide , Lutzemberger Giovanni , Poli Davide , Duenas-Martinez Pablo
Published: February 2021

Stochastic operation of power systems has risen attention of researchers as fluctuating energy sources like renewables are being increasingly integrated into existing grids. Uncertainties can be higher in small power systems like isolated microgrids, where both renewables and load can be extremely unpredictable, thus causing increasing operating costs and business risks. In the last years, many approaches have been proposed to account for uncertainties in off-grid microgrids, usually simulating several size, load and renewables scenarios. Among them, a simplified stochastic approach, namely Aggregating-Rule-based Stochastic Optimization (ARSO), which decomposes the N-scenario problem into N deterministic subproblems whose solutions are finally processed and aggregated, has been recently proposed with interesting results in terms of optimality of results and computational requirements. In this paper, two ARSO approaches are compared with standard stochastic and deterministic methodologies used to operate isolated microgrids, to assess advantages and drawbacks of all these techniques and their ability in handling uncertainties. The two ARSO methodologies differ in the aggregating rule: to take into account the load and RES forecasting errors, the Improved-ARSO employs a Monte Carlo procedure, whereas the Mixed ARSO technique makes use of statistical rules. A numerical case study for a typical isolated microgrid in Africa is proposed and discussed.
Mini-grid hybridization and demand side management on non-interconnected small islands: the case study of Ustica, Italy
Authors: Cherubini Paolo , Frate Guido Francesco , Maggiore Marco Antonino , Micangeli Andrea , Ferrari Lorenzo
Published: February 2021

Small Mediterranean islands are typically served by mini-grids based on inefficient, polluting and costly diesel generators that provide electricity and freshwater through desalination plants. The study focuses on the case study of the Italian island of Ustica, for which the actual consumption and generation load profiles for 2018 have been used to simulate different scenarios through HOMER Pro software. The scenarios tested the possible integration of renewable energy sources (photovoltaic, small wind turbines) and electrochemical storage in the system, based on a techno-economic, financial, and environmental analysis. In addition to generation-side interventions, demand-side management strategies have been evaluated by considering the desalter as a deferrable load and by introducing energy efficiency measures. Finally, a sensitivity analysis on the most influential parameters (diesel price, discount rate) has been conducted on the base case scenario. The proposed technical solutions are compatible with the environmental and regulatory constraints of the island and lead to reduced emissions and long-term savings. The savings would enable a reduction in the cross-subsidy that the mainland electricity users pay to cover the higher costs incurred for diesel generation in non-interconnected small islands.
Techno-Economic Analysis of Power-to-Heat Systems
Authors: Vannoni Alberto , Sorce Alessandro , Traverso Alberto , Massardo Aristide Fausto
Published: February 2021

The heating and cooling sector, responsible for a large fraction of greenhouse emissions, may have a large scale impact on the energy system evolution contributing to smart industrial and domestic electrification; at the same time the recent increase of renewable energy sources installation, posing a threat in terms of grid stability, makes available a considerable amount of clean and cheap electrical energy during peak hours production. Power to heat technologies constitute a promising solution to face both these issues reducing the electric demand variability and decarbonizing the heat production. Large vapor compression heat pumps are a reliable technology able to compete, under the economic point of view, with the heat-only-boilers in order to serve district heating networks. Performance and economic profitability of a compression cycle is strongly dependent on available thermal source and the temperature of water delivered to the network. The present work explores and compares performance and economic indicators under different installation conditions, considering compression heat pumps employing four different fluids: a traditional HCF (R134a) and three natural fluids, ammonia (R717), butane (R600), and propane (R290), often preferred nowadays to HCFs due to the lower global warming potential.
Analysis of labour market needs for engineers with enhanced knowledge in sustainable renewable energy solutions in the built environment in some Asian countries
Authors: Cioccolanti Luca , Moglie Matteo , Mahkamov Khamid , Paksoy Halime , Chen Chao , Lin Jie , Li Caiyun , Guan Yong , Zhou Wenhe , Abdullah Ermira , Mohd Radzi Mohd Amran , Shafie Suhaidi , Alimuddin Zainal , Yusof Idroas Mohamad , Yew Heng Teoh , Azmier Ahmad Mohd , Azman Miskam Muhamad , Kraitong Kwanchai , Wongsapai Wongkot , Chaichana Chatchawan , Damronsak Det
Published: February 2021

Despite the rapid growth in the uptake of renewable energy technologies, the educational profile and the skills gained at University level do not always comply with the practical needs of the organisations working in the field. Furthermore, even though the residential sector has very high potential in curbing its CO2 emissions worldwide thus meeting the challenging goals set out by the international agreements, such reduction has been limited so far. Within this context, the ‘Skybelt’ project, co-funded by the EU under the framework of the Erasmus + programme aims at enhancing in several Universities of Asia and Europe the engineering skills of students of all level for application of sustainable renewable energy solutions in the built environment. With the target of increasing the employability of graduates and the impact of the project, a survey on the labour market needs for specialists with enhanced knowledge and skills in the topic of the project has been conducted in the related Asian countries. Hence, relevant industries, labour market organisations and other stakeholders have been interviewed and the main results of this analysis is reported in the present paper. As first outcome of this activity, the obtained results have been considered in the selection of the modules to be improved according to a student centred study approach.
Carnot cycle in practice: compensating inefficiencies of ORC expanders through thermal regeneration
Authors: Lefebvre Lucie , De Paepe Ward , Ferrari Mario L. , Traverso Alberto
Published: February 2021

The Organic Rankine Cycle (ORC) is a thermodynamic cycle that can operate with a hot source over a wide range of temperatures, especially with low-grade heat (below 200°C). One of the main limitations for the success of small-scale ORC cycles (few to 100 kWe) is the relatively low isentropic efficiency of the typically used turbomachinery. Low turbine efficiency leads to low ORC cycle performance. To increase the performance of the cycle, the turbine efficiency must be increase, however, this significantly increases the cost of the machinery, making the cycle less profitable. In this work, the performance evaluation of low-temperature ORC cycles (100-150°C) with heat extraction along the expansion process is investigated, in an attempt to overcome this limitation. The studied cycle works in the same way as a conventional ORC, except that during the expansion process, heat is extracted. This heat is re-used later in the cycle, just before the hot source, allowing to reduce its load. The different cycles presented in this paper, using pentane as working fluid, are compared based on their exergetic and energetic efficiencies. The influence of three parameters on the cycle performance is studied: the regeneration ratio, the maximum temperature of the cycle and the turbine isentropic efficiency. In the case of a cycle using pentane with a maximum temperature of 150 °C and an turbine isentropic efficiency of 65%, the energy efficiency increases from 6.2% to 16.3% when going from no regeneration to full regeneration, and the exergy efficiency increases from 21.1 to 45.8%.. Secondly, the influence of the maximum temperature of the cycle is studied. Using pentane as the working fluid, the higher the maximum temperature is, the larger the benefits of heat extraction. However, this temperature cannot exceed the critical temperature of the organic fluid to stay in the case of a subcritical cycle. Finally, considering the turbine isentropic efficiency, it is possible to demonstrate that using a less efficient turbine, for example in small ORC systems, the performance of a cycle with an ideal turbine isentropic efficiency (100%) can be achieved compensating at cycle level the turbine losses with the heat extraction along the expansion process.
La fièvre hémorragique de Crimée-Congo, une future problématique de santé en France ?
Authors: Reynard Olivier , Ritter Maureen , Martin Baptiste , Volchkov Viktor
Published: February 2021

Le virus de la fièvre hémorragique de Crimée-Congo (CCHFV) est l’agent étiologique d’une fièvre hémorragique grave affectant l’Afrique, l’Asie et le sud de l’Europe. Les modifications climatiques de ces dernières décennies induisent depuis peu une remontée de l’aire de distribution de ce virus. Encore peu de données scientifiques sont disponibles sur les interactions avec son vecteur, la tique, ou sur sa biologie propre. Cependant, la présence avérée d’infections humaines en Espagne et des sérologies positives dans le cheptel corse pourraient bien concentrer l’attention sur ce pathogène. Cette revue fait le point sur l’évolution des connaissances éco-épidémiologiques de ce virus, notamment en Europe et plus particulièrement en France.
TGF-β : un acteur essentiel de la perte d’immunité innée du tissu cutané au cours du vieillissement
Authors: Gutierrez-Mateyron Emie , Bobé Pierre
Published: February 2021

Pour la sixième année, dans le cadre du module d’enseignement « Physiopathologie de la signalisation » proposé par l’université Paris-sud, les étudiants du Master « Biologie Santé » de l’université Paris-Saclay se sont confrontés à l’écriture scientifique. Ils ont sélectionné une quinzaine d’articles scientifiques récents dans le domaine de la signalisation cellulaire présentant des résultats originaux, via des approches expérimentales variées, sur des thèmes allant des relations hôte-pathogène aux innovations thérapeutiques, en passant par la signalisation hépatique et le métabolisme. Après un travail préparatoire réalisé avec l’équipe pédagogique, les étudiants, organisés en binômes, ont ensuite rédigé, guidés par des chercheurs, une Nouvelle soulignant les résultats majeurs et l’originalité de l’article étudié. Ils ont beaucoup apprécié cette initiation à l’écriture d’articles scientifiques et, comme vous pourrez le lire, se sont investis dans ce travail avec enthousiasme ! Trois de ces Nouvelles sont publiées dans ce numéro, les autres le seront dans des prochains numéros.
Thermal behavior of lead silicate vitreous materials for sealants
Authors: Mocioiu Ana-Maria , Mocioiu Oana Cătălina
Published: February 2021

The objective of our investigations consists in the thermal characterization of SiO2-PbO-Na2O vitreous materials in order to establish their properties for applications mainly as sealants. In order to evaluate the vitreous material − metal adherence, the thermal expansion coefficients (α) from experimental and theoretic data were determined. The differential thermal analysis of studied materials give the information about temperatures characteristic to glass transition, crystallization and melting. Dilatometer measurements were performed in air atmosphere in order to establish thermal coefficients of the materials. Softening and flowing characteristic of the vitreous materials were established by heating microscope measurements. The difference between thermal expansion coefficient (α) of the vitreous materials (10.2 × 10−6K−1 and 17.6 × 10−6K−1) and thermal expansion coefficient of the steel substrate OL 38 (10.8 × 10−6K−1) is under 37%. This value is fit for a good adherence between materials.