bluuebunny/crossref_metadata_2025 huggingface dataset:
Prevalence of and Risk Factors for Suicide Attempts Among Patients With Severe Psychiatric Disorders in Eastern Morocco
Authors: Barrimi Mohammed , Serraj Khalid , Rammouz Ismail , Alouane Rachid , Messaoudi Najoua , Bellaoui Mohammed
Published: October 2021

Abstract. Background: Suicide attempts are common in patients with severe psychiatric disorders; however, they are rarely studied in this population. Aims: To investigate the prevalence and risk factors associated with suicide attempts among patients with severe psychiatric disorders. Method: This is a cross-sectional study of patients admitted to the Mohammed VI University Hospital of Psychiatry in Oujda, Morocco. Results: A total of 250 patients with a psychiatric disorder were recruited in this study. Among these, 78 cases (31.2%) had a personal history of suicide attempts. A personal history of suicide attempt was significantly higher among women compared to men (45.5% vs. 27.2%, p = .0099). The most common method of suicide attempts was jumping from heights (31%). Patients with a personal history of suicide attempts had a significantly higher prevalence of alcohol consumption ( p = .0063), family history of psychiatric disorders ( p = .002), family history of suicide attempt ( p = .00004), and family history of suicide ( p = .018) compared to those who had never made suicide attempts. Limitations: As suicidal behavior is highly stigmatized in Morocco, the number of patients who have made a suicide attempt may be underestimated. Conclusion: Our findings justify the need to provide specialized support to psychiatric patients with risk factors for suicide attempts.
Dominance of Wildfires Impact on Air Quality Exceedances During the 2020 Record‐Breaking Wildfire Season in the United States
Authors: Li Yunyao , Tong Daniel , Ma Siqi , Zhang Xiaoyang , Kondragunta Shobha , Li Fangjun , Saylor Rick
Published: October 2021

The western United States experienced a record‐breaking wildfire season in 2020. This study quantifies the contribution of wildfire emissions to the exceedances of health‐based National Ambient Air Quality Standard (NAAQS) for fine particles (PM2.5) by comparing two CMAQ simulations, with and without wildfire emissions. During August to October 2020, western wildfires contributed 23% of surface PM2.5 in the contiguous US (CONUS), with a larger contribution in Pacific Coast (43%) and Mountain Region (42%). Consequently, wildfires were the primary contributor to the 3,720 observed exceedances. The wildfire influence peaked on September 14th, 2020, when 273 exceedances were recorded and wildfire emissions contributed 41%, 81%, and 72% to surface PM2.5 concentrations in the CONUS, Pacific Coast, and Mountain Region, respectively. Our finding highlights the predominating influence of wildfires on air quality, and potentially human health, that is expected to grow with increasing fire activities, while anthropogenic emissions decrease.
Prognostic value of baseline imaging and clinical features in patients with advanced hepatocellular carcinoma
Authors: Öcal Osman , Ingrisch Michael , Ümütlü Muzaffer Reha , Peynircioglu Bora , Loewe Christian , van Delden Otto , Vandecaveye Vincent , Gebauer Bernhard , Zech Christoph J. , Sengel Christian , Bargellini Irene , Iezzi Roberto , Benito Alberto , Pech Maciej , Malfertheiner Peter , Ricke Jens , Seidensticker Max
Published: October 2021

Aims

To investigate the prognostic value of baseline imaging features for overall survival (OS) and liver decompensation (LD) in patients with hepatocellular carcinoma (HCC).

Design

Patients with advanced HCC from the SORAMIC trial were evaluated in this post hoc analysis. Several radiological imaging features were collected from baseline computed tomography (CT) and magnetic resonance imaging (MRI) imaging, besides clinical values. The prognostic value of these features for OS and LD (grade 2 bilirubin increase) was quantified with univariate Cox proportional hazard models and multivariate Least Absolute Shrinkage and Selection Operator (LASSO) regression.

Results

Three hundred and seventy-six patients were included in this study. The treatment arm was not correlated with OS. LASSO showed satellite lesions, atypical HCC, peritumoral arterial enhancement, larger tumour size, higher albumin–bilirubin (ALBI) score, liver–spleen ratio <1.5, ascites, pleural effusion and higher bilirubin values were predictors of worse OS, and higher relative liver enhancement, smooth margin and capsule were associated with better OS. LASSO analysis for LD showed satellite lesions, peritumoral hypointensity in hepatobiliary phase, high ALBI score, higher bilirubin values and ascites were predictors of LD, while randomisation to sorafenib arm was associated with lower LD.

Conclusions

Imaging features showing aggressive tumour biology and poor liver function, in addition to clinical parameters, can serve as imaging biomarkers for OS and LD in patients receiving sorafenib and selective internal radiation therapy for HCC.
Gd-admixed (Lu,Gd)AlO3 single crystals: breakthrough in heavy perovskite scintillators
Authors: Pokorný Martin , Babin Vladimir , Beitlerová Alena , Jurek Karel , Polák Jan , Houžvička Jindřich , Pánek Dalibor , Parkman Tomáš , Vaněček Vojtěch , Nikl Martin
Published: October 2021

We report a breakthrough concept for a bulk single crystal as a heavy aluminum perovskite scintillator, where due to bandgap engineering by a balanced Gd admixture in a Lu cation sublattice, the scintillation performance dramatically increases. In an optimized composition of (Lu, Gd)AlO3:Ce (LuGdAP:Ce), the light yield approaches 21,000 phot/MeV, which is close to that of classical but much less dense YAP:Ce and 50% higher than the best LuYAP:Ce reported in the literature. Moreover, contrary to LuYAP:Ce, the LuGdAP host maintains a high effective atomic number close to that of LuAP:Ce (Zeff = 64.9), which is comparable to commercial LSO:Ce. An enormous decrease in afterglow on the millisecond time scale and acceleration in the rise time of the scintillation response further increase the application potential of the LuGdAP host. The related acceleration of the transfer stage in the scintillation mechanism due to diminishing electron trap depths is proven by thermally stimulated luminescence (TSL). Furthermore, we quantitatively characterize and model the energy transfer processes that are responsible for the change in the photoluminescence and scintillation decay kinetics of Ce3+ in the LuGdAP matrix. Such an innovative (Lu, Gd)AP:Ce scintillator will become competitive for use in applications that require heavy, fast, and high light yield bulk scintillators.
Association of snR190 snoRNA chaperone with early pre-60S particles is regulated by the RNA helicase Dbp7 in yeast
Authors: Jaafar Mariam , Contreras Julia , Dominique Carine , Martín-Villanueva Sara , Capeyrou Régine , Vitali Patrice , Rodríguez-Galán Olga , Velasco Carmen , Humbert Odile , Watkins Nicholas J. , Villalobo Eduardo , Bohnsack Katherine E. , Bohnsack Markus T. , Henry Yves , Merhi Raghida Abou , de la Cruz Jesús , Henras Anthony K.
Published: October 2021

Synthesis of eukaryotic ribosomes involves the assembly and maturation of precursor particles (pre-ribosomal particles) containing ribosomal RNA (rRNA) precursors, ribosomal proteins (RPs) and aplethoraof assembly factors (AFs). Formation of the earliest precursors of the 60S ribosomal subunit (pre-60S r-particle) is among the least understood stages of ribosome biogenesis. It involves the Npa1 complex, a protein module suggested to play a key role in the early structuring of the pre-rRNA. Npa1 displays genetic interactions with the DExD-box protein Dbp7 and interacts physically with the snR190 box C/D snoRNA. We show here that snR190 functions as a snoRNA chaperone, which likely cooperates with the Npa1 complex to initiate compaction of the pre-rRNA in early pre-60S r-particles. We further show that Dbp7 regulates the dynamic base-pairing between snR190 and the pre-rRNA within the earliest pre-60S r-particles, thereby participating in structuring the peptidyl transferase center (PTC) of the large ribosomal subunit.
The RNA helicase Dbp7 promotes domain V/VI compaction and stabilization of inter-domain interactions during early 60S assembly
Authors: Aquino Gerald Ryan R. , Hackert Philipp , Krogh Nicolai , Pan Kuan-Ting , Jaafar Mariam , Henras Anthony K. , Nielsen Henrik , Urlaub Henning , Bohnsack Katherine E. , Bohnsack Markus T.
Published: October 2021

Early pre-60S ribosomal particles are poorly characterized, highly dynamic complexes that undergo extensive rRNA folding and compaction concomitant with assembly of ribosomal proteins and exchange of assembly factors. Pre-60S particles contain numerous RNA helicases, which are likely regulators of accurate and efficient formation of appropriate rRNA structures. Here we reveal binding of the RNA helicase Dbp7 to domain V/VI of early pre-60S particles in yeast and show that in the absence of this protein, dissociation of the Npa1 scaffolding complex, release of the snR190 folding chaperone, recruitment of the A3 cluster factors and binding of the ribosomal protein uL3 are impaired. uL3 is critical for formation of the peptidyltransferase center (PTC) and is responsible for stabilizing interactions between the 5′ and 3′ ends of the 25S, an essential pre-requisite for subsequent pre-60S maturation events. Highlighting the importance of pre-ribosome remodeling by Dbp7, our data suggest that in the absence of Dbp7 or its catalytic activity, early pre-ribosomal particles are targeted for degradation.
Ultra-selective molecular-sieving gas separation membranes enabled by multi-covalent-crosslinking of microporous polymer blends
Authors: Chen Xiuling , Fan Yanfang , Wu Lei , Zhang Linzhou , Guan Dong , Ma Canghai , Li Nanwen
Published: October 2021

High-performance membranes exceeding the conventional permeability-selectivity upper bound are attractive for advanced gas separations. In the context microporous polymers have gained increasing attention owing to their exceptional permeability, which, however, demonstrate a moderate selectivity unfavorable for separating similarly sized gas mixtures. Here we report an approach to designing polymeric molecular sieve membranes via multi-covalent-crosslinking of blended bromomethyl polymer of intrinsic microporosity and Tröger’s base, enabling simultaneously high permeability and selectivity. Ultra-selective gas separation is achieved via adjusting reaction temperature, reaction time and the oxygen concentration with occurrences of polymer chain scission, rearrangement and thermal oxidative crosslinking reaction. Upon a thermal treatment at 300 °C for 5 h, membranes exhibit an O2/N2, CO2/CH4 and H2/CH4 selectivity as high as 11.1, 154.5 and 813.6, respectively, transcending the state-of-art upper bounds. The design strategy represents a generalizable approach to creating molecular-sieving polymer membranes with enormous potentials for high-performance separation processes.
Generation of hydroxyl radical-activatable ratiometric near-infrared bimodal probes for early monitoring of tumor response to therapy
Authors: Wu Luyan , Ishigaki Yusuke , Zeng Wenhui , Harimoto Takashi , Yin Baoli , Chen Yinghan , Liao Shiyi , Liu Yongchun , Sun Yidan , Zhang Xiaobo , Liu Ying , Liang Yong , Sun Pengfei , Suzuki Takanori , Song Guosheng , Fan Quli , Ye Deju
Published: October 2021

Tumor response to radiotherapy or ferroptosis is closely related to hydroxyl radical (•OH) production. Noninvasive imaging of •OH fluctuation in tumors can allow early monitoring of response to therapy, but is challenging. Here, we report the optimization of a diene electrochromic material (1-Br-Et) as a •OH-responsive chromophore, and use it to develop a near-infrared ratiometric fluorescent and photoacoustic (FL/PA) bimodal probe for in vivo imaging of •OH. The probe displays a large FL ratio between 780 and 1113 nm (FL780/FL1113), but a small PA ratio between 755 and 905 nm (PA755/PA905). Oxidation of 1-Br-Et by •OH decreases the FL780/FL1113while concurrently increasing the PA755/PA905, allowing the reliable monitoring of •OH production in tumors undergoing erastin-induced ferroptosis or radiotherapy.
AtomSets as a hierarchical transfer learning framework for small and large materials datasets
Authors: Chen Chi , Ong Shyue Ping
Published: October 2021

Predicting properties from a material’s composition or structure is of great interest for materials design. Deep learning has recently garnered considerable interest in materials predictive tasks with low model errors when dealing with large materials data. However, deep learning models suffer in the small data regime that is common in materials science. Here we develop the AtomSets framework, which utilizes universal compositional and structural descriptors extracted from pre-trained graph network deep learning models with standard multi-layer perceptrons to achieve consistently high model accuracy for both small compositional data (<400) and large structural data (>130,000). The AtomSets models show lower errors than the graph network models at small data limits and other non-deep-learning models at large data limits. They also transfer better in a simulated materials discovery process where the targeted materials have property values out of the training data limits. The models require minimal domain knowledge inputs and are free from feature engineering. The presented AtomSets model framework can potentially accelerate machine learning-assisted materials design and discovery with less data restriction.
A recombinant measles virus vaccine strongly reduces SHIV viremia and virus reservoir establishment in macaques
Authors: Nzounza Patrycja , Martin Grégoire , Dereuddre-Bosquet Nathalie , Najburg Valérie , Gosse Leslie , Ruffié Claude , Combredet Chantal , Petitdemange Caroline , Souquère Sylvie , Schlecht-Louf Géraldine , Moog Christiane , Pierron Gérard , Le Grand Roger , Heidmann Thierry , Tangy Frédéric
Published: October 2021

Replicative vectors derived from live-attenuated measles virus (MV) carrying additional non-measles vaccine antigens have long demonstrated safety and immunogenicity in humans despite pre-existing immunity to measles. Here, we report the vaccination of cynomolgus macaques with MV replicative vectors expressing simian-human immunodeficiency virus Gag, Env, and Nef antigens (MV-SHIV Wt) either wild type or mutated in the immunosuppressive (IS) domains of Nef and Env antigens (MV-SHIV Mt). We found that the inactivation of Nef and Env IS domains by targeted mutations led to the induction of significantly enhanced post-prime cellular immune responses. After repeated challenges with low doses of SHIV-SF162p3, vaccinees were protected against high viremia, resulting in a 2-Log reduction in peak viremia, accelerated viral clearance, and a decrease -even complete protection for nearly half of the monkeys- in reservoir cell infection. This study demonstrates the potential of a replicative viral vector derived from the safe and widely used measles vaccine in the development of a future human vaccine against HIV-1.
The impact of on-premises piped water supply on fecal contamination pathways in rural Zambia
Authors: Winter James C. , Darmstadt Gary L. , Boehm Alexandria B. , Davis Jennifer
Published: October 2021

Reliable access to water, sanitation, and hygiene (WASH) services is a critical component of child health and development. However, as piped water systems with taps conveniently close to households are rare in rural, sub-Saharan Africa, there is limited evidence of their impact. We conducted a quasi-experimental study in four rural villages of southern Zambia between April 2018 and May 2019 in which we measured the impact of installing on-premises piped water systems on fecal contamination of stored water and caregivers’ hands. Gaining access to piped water was associated with a 0.5 log10 reduction of E. coli concentration in drinking water (p < 0.05) but no changes in hand contamination. The piped water systems in this study reduced the median distance to a safe drinking water source by over 90%, but we measured only small improvements in microbiological outcomes and no changes in the duration of self-reported, in-home water storage. These findings emphasize the need for future impact assessments of piped water systems to measure a comprehensive set of indicators directly linked to human well-being such as time savings.
Turning waste into treasure: chicken eggshell membrane derived fluorescent carbon nanodots for the rapid and sensitive detection of Hg2+ and glutathione
Authors: Zhang Hongding , Wu Sifei , Xing Zhenhua , Wang Hai-Bo
Published: October 2021

Fluorescence turn-off–on strategy for Hg2+ and GSH detection.
Gold-based immunochromatographic assay strip for the detection of quinclorac in foods
Authors: Wu Huihui , Xu Xinxin , Liu Liqiang , Xu Liguang , Kuang Hua , Xu Chuanlai
Published: October 2021

Gold-based immunochromatographic assay strip for the detection of quinclorac in foods.
Rapid and sensitive online determination of ozone via gas–liquid chemiluminescence synergistically enhanced by graphene quantum dots and Triton X-100
Authors: Tang Lianbo , Wang Zhuqing , Chen Qi , Feng Yangrun , Dong yuan  , Tan Wenyuan , Fu Dayou
Published: October 2021

The determination of the ozone concentration in the atmosphere is an urgent need but most current methods are limited by large-scale equipment or complex procedures.
Can the local electric field be a descriptor of catalytic activity? A case study on chorismate mutase
Authors: Siddiqui Shakir Ali , Dubey Kshatresh Dutta
Published: October 2021

The local electric field (LEF) of the enzyme along the reaction axis can be an efficient descriptor for the enzymatic activity.
Origins of the photoinitiation capacity of aromatic thiols as photoinitiatiors: a computational study
Authors: Fındık Volkan , Fındık Basak Koca , Aviyente Viktorya , Monari Antonio
Published: October 2021

In this work, we report the photophysical properties of three thiol derivatives, commonly used as photoinitiators in thiol–ene free radical polymerization, the ultimate goal being to rationalize the main reason behind the photoinitiation efficiency.
Phosphorous-substituted redox-active ligands in base metal hydrosilylation catalysis
Authors: Sharma Anuja , Trovitch Ryan J.
Published: October 2021

The preparation of redox-active ligand supported manganese, iron, cobalt, and nickel compounds that feature hemilabile phosphine moieties has allowed for highly efficient hydrosilylation catalysis.
Iron oxidation to amplify the Na and Li storage capacities of nano-sized maricite NaFePO4
Authors: Boyadzhieva Tanya , Koleva Violeta , Markov Pavel , Stoyanova Radostina
Published: October 2021

Nanosized maricite-type NaFePO4is oxidized to NASICON-type Na3Fe2(PO4)3at mild conditions. The oxidized maricite displays a dramatic improvement of the specific capacity and cycling stability when used as an electrode in Na- and Li half-cells.
Boosting the methanolysis of polycarbonate by the synergy between ultrasound irradiation and task specific ionic liquids
Authors: D'Anna Francesca , Sbacchi Maria , Infurna Giulia , Dintcheva Nadka Tz. , Marullo Salvatore
Published: October 2021

Combined use of task specific ionic liquids and ultrasound irradiation gives a suitable protocol to perform methanolysis of polycarbonate in a sustainable way.
Recent advances in the incorporation of CO2 for C–H and C–C bond functionalization
Authors: Pimparkar Sandeep , Dalvi Aishwarya K. , Koodan Adithyaraj , Maiti Siddhartha , Al-Thabaiti Shaeel Ahmed , Mokhtar Mohamed , Dutta Arnab , Lee Yong Rok , Maiti Debabrata
Published: October 2021

Functionalization with CO2: This tutorial review is focused on various approaches developed so far for functionalization of unsaturated C–C & C–H bonds using CO2 to achieve carboxylation, lactonization & lactamization by metal and metal free methods.
A handy reversible bonding technology and its application on fabrication of an on-chip liquid metal micro-thermocouple
Authors: Hong Jie , Gong Jiahao , Li Qian , Deng Zhongshan , Gui Lin
Published: October 2021

An on-chip liquid metal based micro-thermocouple based on a reversible bonding technology.
Selective colorimetric sensing of deferoxamine with 4-mercaptophenol- and mercaptoacetic acid-functionalized gold nanoparticles via Fe(iii) chelation
Authors: Koç Ömer Kaan , Benli Elif Ezgi , Karahan Nurşah , Üzer Ayşem , Apak Reşat
Published: October 2021

The multidentate deferoxamine ligand can selectively aggregate the Fe(iii)-attached AuNPs@(4MP–MAA) colorimetric nanoprobe, whereas other bidentate iron chelators cannot bridge the nanoparticles.
Controllable fabrication and photocatalytic performance of nanoscale single-layer MoSe2 islands with substantial edges on an Ag(111) substrate
Authors: Lu Jianchen , Niu Gefei , Ren Xiao , Bao Deliang , Chen Hui , Yang Haitao , Lin Xiao , Du Shixuan , Gao Hong-Jun
Published: October 2021

We demonstrate a controllable synthesis strategy of single-layer 2D MoSe2 islands with excellent photocatalytic activity.
Preparing polythiophene derivative with alternating alkyl and thioalkyl side chains via Kumada coupling for efficient organic solar cells
Authors: Xie Ziyi , Wei Qingyun , Shan Tong , Zheng Xiaoyang , Zhang Yi , Zhong Hongliang
Published: October 2021

A polythiophene, namely PTST with alternating alkyl and thioalkyl side chains, is prepared by Kumada catalyst-transfer polycondensation. PTST can hierarchically pre-aggregate in solution, and then form a favorable morphology in organic solar cells.
Gravity compensation and optimal control of actuated multibody system dynamics
Authors: Nekoo Saeed Rafee , Acosta José Ángel , Ollero Anibal
Published: October 2021

This work investigates the gravity compensation topic, from a control perspective. The gravity could be levelled by a compensating mechanical system or in the control law, such as proportional derivative (PD) plus gravity, sliding mode control, or computed torque method. The gravity compensation term is missing in linear and nonlinear optimal control, in both continuous‐ and discrete‐time domains. The equilibrium point of the control system is usually zero and this makes it impossible to perform regulation when the desired condition is not set at origin or in other cases, where the gravity vector is not zero at the equilibrium point. The system needs a steady‐state input signal to compensate for the gravity in those conditions. The stability proof of the gravity compensated control law based on nonlinear optimal control and the corresponding deviation from optimality, with proof, are introduced in this work. The same concept exists in discrete‐time control since it uses analog to digital conversion of the system and that includes the gravity vector of the system. The simulation results highlight two important cases, a robotic manipulator and a tilted‐rotor hexacopter, as an application to the claimed theoretical statements.
How pandemic affects occupants’ buildings perception: questionnaires investigation and preliminary results
Authors: Nardi Iole , Palladino Domenico
Published: October 2021

The COVID-19 pandemic has changed the living habits all over the world. Countries experienced multiple lockdowns, causing offices, restaurants, school and almost all the economic activities to close. The saying “stay home stay safe”, to which we were invited for preventing the virus spread, and the rise of smart-working, lead to an exponential increase in the time spent in our homes. In this sense, the way to live our homes has changed. Spaces and rooms that (before pandemic) were occupied for just a few hours a day, have become the main places for studying, working, playing or even have fitness. More than ever, people had to face the energy related problems of their house: air leakages, energy losses, expensive billings, and thermal discomfort. This study arises from considerations on buildings use after the pandemic, and it addresses the consequences of COVID-19 to building perception. Anonymous questionnaires were proposed broad wide, asking through a multi-stage survey to compare the feeling before and after the pandemic, also in comparison to the billing of the energy carriers. Results have been analysed, showing how the pandemic has changed the living perception.
Influence of environmental boundary conditions on convective heat transfer coefficients of wall internal surface
Authors: de Rubeis Tullio , Evangelisti Luca , Guattari Claudia , De Lieto Vollaro Roberto , Asdrubali Francesco , Ambrosini Dario , Paoletti Domenica
Published: October 2021

In this study, convective heat transfer phenomena were investigated by means of a Guarded Hot Box (GHB) apparatus. An experimental setup characterized by air and surface temperature probes, and a hot-wire anemometer was used. Five small fans were installed in the metering chamber to generate a forced air flow characterized by different velocity values. So, the GHB was used for investigating the influence of different air speed values on internal convective coefficients. Considering horizontal heat fluxes, an internal convective coefficient values of 2.5 W/m2K is reported in the Standard ISO 6946. However, no exhaustive description about this value is provided. The aim of this work is to experimentally determine the internal thermal surface resistance, quantifying how the convective heat transfer coefficient varies as air velocity changes.
The choice of appropriate generator systems to enhance the renewable energy share in buildings. A comparison between PV-assisted heat pumps and biomass boilers
Authors: Bruno Roberto , Bevilacqua Piero , Perrella Stefania , Cirone Daniela , Arcuri Natale
Published: October 2021

Low-energy buildings are generally equipped with generation systems driven by renewable sources. Regarding heating and DHW production, two choices appear appropriate: PV assisted heat pumps and biomass boilers. In this paper, by means of TRNSYS dynamic simulations, the non-renewable primary energy was determined for two buildings located in different climatic contexts by varying the PV size to consider the actual self-consumed electricity of commercial devices. Results showed that in cold climates biomass boilers are more suggested, especially in unfavourable climatic zones, whereas the COP of air-water heat pumps is strongly penalized by the outdoor temperatures and in many cases the self-consumed PV electricity does not limit the grid intervention adequately. However, in building with limited thermal energy demands and in favorable climates, suitable PV sizes make heat pumps more performant than biomass boilers. The same calculations were conducted with the quasi-steady approach, in accordance with the Italian building energy certification procedure, observing a favorable scenario in a heating plant equipped with a PV assisted heat pump because it assumes the renewable electricity entirely absorbed, while the accounting of the actual self-consumed share produces a greater demand of non-renewable energy.
Tool for supporting local energy strategies: forecasting energy plans with Artificial Neural Network in Umbria Region
Authors: Palladino Domenico , Nardi Iole
Published: October 2021

In order to reduce the greenhouse gas emission and to improve the energy efficiency of buildings, European Member States have to plan medium-to-long term strategies as reliable as possible. In this context, the present work aims to discuss the potentiality of Artificial Neural Network (ANN) as a support tool for medium-to-long term forecasting analysis of energy efficiency strategies in Umbria Region (central Italy) chosen as case study. Parametric energy simulations of several archetypes buildings were carried out in compliance with the current Italian regulations by changing the form, thermal properties, boundary conditions, and technical building systems. An ANN able to forecast primary energy need was trained to forecast the energy need of building-stock of Umbria Region and to evaluate the effectiveness of several potential energy actions (such as thermal coat or technical building systems replacement) over the years. Results confirm the potential of use of ANN as a support tool in energy forecasting analysis for local Authorities. ANN is capable of forecasting different future scenarios allowing correctly planning energy actions to be implemented as well as their priority. The results open to several scenarios of interest, such as the application of the same approach at national level.
Lithium Batteries Cooling by Phase Change Material Partially Filled with Metal Foam
Authors: Buonomo Bernardo , d’Alesio Fabio , Manca Oronzio , Menale Ferdinando , Nardini Sergio
Published: October 2021

Electric cars can be a turning point for climate problems. One of the main problems of electric cars is the thermal control of the batteries, since below and above a certain temperature range, the vehicle’s range decreases abruptly, creating inconveniences to the owners of these cars.

The thermal control of lithium batteries for electric cars must take into account both the problems of thermal rise due to the operation of the battery itself, and the climatic conditions outside the vehicle that negatively affect the performance of the car, reducing both the autonomy and the battery life. In this study, a thermal control system based on a phase change material (PCM) partially filled with metallic foam is investigated to evaluate its possible use in the cooling of lithium batteries. A two-dimensional model is considered to numerically study thermal control with different chargedischarge cycles. The metal foam partially fills the PCM. The governing equations, written assuming the local thermal equilibrium for the metal foam, are solved by the finite volume method using the ANSYS Fluent commercial code. Different cases are simulated for different values of the external convective heat transfer coefficient. The results, carried out for metal foams and PCM, are given in terms of temperature and liquid fraction. In addition, some comparisons with pure PCM and fully foam filled PCM are provided within the thermal control system to show the advantages of the composite thermal control system with PCM inside the metal foam.
The experience on a sport centre pilot plant with solar assisted heat pump and a look forward for new control strategies and technology upgrade
Authors: Tagliafico Luca Antonio , Cavalletti Alessandro , Marafioti Chiara , Marchitto Annalisa
Published: October 2021

The pilot plant at the sport palace Palacus in Genoa is heated by a solar assisted heat pump, interfaced with a solar hybrid field and two integration gas burners. The heating system has been operating since 2012/13 and its performances have been collected almost continuously by means of a dedicated data acquisition system. The information and the experience acquired have been applied to the design of the revamping of the system, also considering the legislative changes occurred in Italy in the past decade, especially about photovoltaic production. The here presented case study allows the definition of some general design strategies to be implemented during the development of a new SAHP plant or when a revamping is required.
Streamers Variability Investigation of a Radio-Frequency Corona Discharge in an Optical Access Engine at Different Speeds and Loads
Authors: Ricci Federico , Martinelli Roberto , Petrucci Luca , Discepoli Gabriele , Grimaldi Carlo Nazareno , Papi Stefano
Published: October 2021

Engine research community interest in the Radio-Frequency corona-based ignition systems is currently gaining in importance mainly due to their capability to ensure robust combustion at challenging operating conditions such as very lean mixture and/or high EGR dilution. The benefits of Corona low-temperature plasma foster the early flame development thanks to combustion precursors production and to a more energetic and volumetric discharge, resulting in a larger amount of involved mixture. The corona discharge generates ionizing waves, named streamers, whose temporal and spatial variability in orientation, length and branching can affect the combustion onset and, therefore, the engine cycle-to-cycle variability.

In this work, the discharge natural luminosity of a RF corona igniter, characterized by four tips electrodes, was recorded in an optically accessible engine via high-speed camera detection. A preliminary statistical analysis of the spatial and temporal streamer variability was performed by operating in motored conditions. Four different engine speeds and two different loads were explored in order to deeply investigate the streamer behaviour at diverse engine operating conditions.

A comparison between a motored and a lean operating condition is also proposed to analyse, at a specific engine speed, the mixture influence on the streamers propagation before the start of the combustion.
Development and Validation of an Advanced Actuator Line Model for Wind Turbines
Authors: Papi Francesco , Melani Pier Francesco , Xie Shengbai , Perrone Carmelo , Scienza Pietro , Balduzzi Francesco , Bianchini Alessandro
Published: October 2021

As wind turbine technology proceeds towards the development of more advanced and complex machines, modelling tools with fidelity higher than the ubiquitous Blade Element Momentum (BEM) method are needed. Among them, the Actuator Line Method (ALM) stands out in terms of accuracy and computational cost. Moving from this background, an advanced ALM method has been developed within the commercial solver CONVERGE®. As elements of novelty, this tool features a Lagrangian method for sampling the local inflow velocity and a piece-wise smearing function for the force projection process. Various sub-models for both Horizontal Axis Wind Turbines (HAWTs) (e.g. the Shen tip loss correction) and Vertical Axis Wind Turbines (VAWTs) (e.g. the MIT dynamic stall model) has also been included. Aim of the research is to address the new challenges posed by modern machines. HAWTs are in fact getting larger and larger, shifting the research focus on the interaction of increasingly deformable blades with the atmosphere at the micro- and mesoscale level. VAWTs on the other hand, whose popularity has arisen in the last years, thanks to their advantages in non-conventional applications, e.g. floating offshore installations, are extremely complex machines to study, due to their inherently unsteady aerodynamics. The approach has been validated on selected test cases, i.e. the DTU 10MW turbine and a real 2-blade H-rotor, for which both high-fidelity CFD and experimental data are available.
Some design guidelines to adapt a Darrieus vertical axis turbine for use in hydrokinetic applications
Authors: Balduzzi Francesco , Melani Pier Francesco , Soraperra Giuseppe , Brighenti Alessandra , Battisti Lorenzo , Bianchini Alessandro
Published: October 2021

The use of vertical-axis turbines is raising interest in the field of hydropower production from rivers or water channels, where suitable mass flows are available, without the need of high water jumps or large construction sites. Although many optimization studies on vertical-axis turbines have been carried out for wind applications, lesser examples exist in the technical literature regarding hydrokinetic turbines. In the latter case, the best trade-off between power output and low structural stress is more dependent on the fluid dynamic loadings rather than the inertial loadings, due to the higher fluid density and lower rotation speed. The present work shows the results of an industrial study case application, in which the design of a traditional three-blade Darrieus rotor has been adapted for operating in water flows via hydrokinetic technology. Some specific design rules will be discussed, showing the different concepts adopted for the machine layout in order to achieve the best efficiency and performance. Multiple geometrical parameters of the rotor configuration were involved during the analysis: the number of rotor blades, i.e. two or three blades, the rotor’s shape, i.e. traditional H-shape or unconventional L-shape, and the use of power augmentation systems. The analysis of the numerical results was focused on the following output targets: maximum power coefficient, optimal tip speed ratio (TSR), rotor thrust, blade normal force and the upstream and downstream flow field influence. The outcome of the study shows how the best configuration differs from the common solutions for wind application. Moreover, a high power enhancement can be achieved while guaranteeing a good compromise in terms of structural loads.
Technical Economic and Environmental analysis of Chemical Looping versus oxyfuel combustion for NGCC power plant
Authors: Bartocci Pietro , Abad Alberto , Cabello Arturo , Zampilli Mauro , Buia Giulio , Serra Angela , Colantoni Simone , Taiana Andrea , Bidini Gianni , Fantozzi Francesco
Published: October 2021

The Power Sector is undergoing a rapid technological change with respect to implementation of low carbon technologies. The IEA Energy Outlook 2017 shows that the investments in Renewables for the first time are equal to those on the fossil sources. It is likely that the conventional gas turbines and internal combustion engines will need to be integrated in systems employing biofuels and/or CCUS (Carbon Capture Usage and Storage). Also, the European Union is moving rapidly towards low carbon technologies (i.e. Energy Efficiency, Smart Grids, Renewables and CCUS), see the Energy Union Strategy. Currently 28% of the installed power capacity in Europe is based on natural gas plants. Gas-based power capacity has reached 418 GW in 2016 and is likely to continue to grow in the future. To efficiently capture the carbon dioxide emissions generated by the combustion of natural gas in the combustion chamber a possible solution could be to adopt new combustion processes, like Chemical Looping Combustion. The combination of CLC and GTs can decrease the efficiency of a combined cycle power plant from 60% to about 40.34%. These performances influence costs and environmental burdens and this is also the same for oxyfuel combustion, which is a competing technology to realize CCS. This paper, starting from literature mass and energy balances of a conventional combined cycle, a combined cycle coupled with chemical looping combustor and a combined cycle coupled with oxyfuel combustion, calculates the reduction of CO2 emissions which can be achieved during the whole life cycle of the power plant and then identifies the value of the carbon credit which is needed to have an interesting payback period for such kind of investment.
How residential CHPs could be integrated in renewable energy communities’ incentive schemes
Authors: Sforzini Matteo , Nicita Gianluigi , Pastore Lorenzo , Lo Basso Gianluigi , de Santoli Livio
Published: October 2021

The present work aims to investigate the integration into renewable energy communities (REC) schemes of micro and mini- Combined Heat and Power (CHP) plants. In detail, it has been evaluated the minimum self-consumption (SC) share needed to even out the revenues coming from the energy efficiency certificates (EECs). In order to establish a SC based tariff for CHP plants a correlation between SC share and the tariff value has been assessed for different commercial plants. A 70% of SC share has been set as a minimum target, which is related to incentive rates of 53 and 39.5 €/MWh, for mini and micro-CHPs, respectively. These values are about 65% lower than the current tariffs set by ARERA (Italian Regulatory Authority for Energy, Networks and Environment) to reward the renewable energy SC. A real building and two CHP plants have been considered as reference case studies. A dynamic simulation has been carried out in order to analyse the proposed incentive scheme in a real application. Starting from a 3-D BIM model, the energy flows have been calculated over one year period. Finally, it has been demonstrated how a SC based tariff can significantly reduce the share of injected electricity into the grid, also promoting the thermal carrier sharing. In so doing, the renewable energy sources intermittency can be easily mitigated and balanced, avoiding additional burdens on public expenditure.
Assessment of a hybrid propulsion system for short-mid range application with a low-order code
Authors: Amerini Alberto , Langone Leonardo , Vadi Riccardo , Andreini Antonio
Published: October 2021

The increase in air traffic expected in the next years must be accompanied by innovation to ensure the lowest possible environmental impact. Hybrid electric-thermal propulsion systems are currently being investigated and could represent a breakthrough for environmental sustainability in the sector. However, the transition to electric propulsion remains challenging due to the current level of energy density related to storage systems, the additional components associated with power conversion and control systems, not to mention the cost of all the associated equipment. The purpose of this study is to carry out a preliminary assessment of a hybrid propulsion system for a short-mid range aircraft. This study investigates the series hybrid configuration, where a turboshaft, a high temperature superconducting (HTS) electric motor, batteries and power converters interact to provide the necessary propulsion for flight. A zero-dimensional procedure is developed to estimate the mass and efficiency of the powertrain components for a selected flight mission. Thermal engines are modeled with the low-order code and coupled with the components of the electric system through a python routine. A comparison in terms of weight and emissions is reported for the designed hybrid propulsion system and the conventional one. The analysis shows that the weight of the two propulsion systems is similar but, the presence of batteries, even considering a higher level of technology than the current one, leads to a significant increase in the weight of the hybrid aircraft. The second part of the study focuses on pollutant emissions, showing that the hybrid system can reduce CO2 emissions by 58% and NOx emissions by 68% compared to the conventional system. Despite the excellent premise, the reduction in payload for the hybrid aircraft causes a reduction in pollutant emissions per passenger only for NOx. For this reason, further technological improvement is needed to make hybrid propulsion advantageous in terms of both payload and pollutant emissions.
Multi-Agent Fuzzy Logic Controller applied to One Lever Variable Pitch Turboprop Aircraft
Authors: Dambrosio Lorenzo
Published: October 2021

Modern aircraft turboprop engines are generally managed by pilots by using the well-established two-levers approach which allows the pilot to control independently the engine thrust (power lever) and the propeller rotational speed (condition lever). On the other hand, the twolevers governing system presents several disadvantages in terms of pilot training, fuel consumption and aircraft maintenance. The one-lever approach tries to solve such drawbacks regulating at the same time the engine power and the propeller pitch. In the present work a Multi-Agent Fuzzy Logic control algorithm has been proposed to implement the one-lever approach for the control of the variable pitch turboprop aircraft propulsion system. The whole aircraft ecosystem has been developed in Simulink® framework to verify the feasibility and performance of the proposed one-lever approach.
New Rotor Blade Profiles Performance Decay in Horizontal Axis Wind Turbines Operating in Aggressive Environment
Authors: Maria De Pratti Giovanni
Published: October 2021

At the present time many wind power plants have been developed in mountainous areas, in off-shore sites also at high latitudes and however operating in harsch climate or aggressive environment conditions. In these conditions HAWT’s rotor blades may experiment erosion, corrosion, exfoliation and icing and these operative conditions may cause a remarkable aerodynamical performance decay resulting in a reduction in energy production due to a lower machines availability too. Traditional aerodynamic profiles, as NACA ones, can show high sensitivity to the surface damage or augmented roughness, while new airfoils as FFA-W1 series may be very useful in maintaining higher aerodynamical performance. In the present paper the aerodynamic performances of new and old airfoils have been analysed and compared on a water table test bench and wind tunnel one, at “La Sapienza” University of Rome in DIMA’s laboratory, in several operative conditions, and, particularly, effects due to icing, erosion and other ones as corrosion and fouling. The results have been compared with literature data to obtain useful indications in design of new rotor blades.
Investigation of effect of heat exchanger size on power output in low-temperature difference Stirling engines
Authors: Hasanovich Linda , Nobes David
Published: October 2021

The Stirling engine is capable of converting any source of thermal energy into kinetic energy, which makes it an attractive option for utilizing low-temperature sources such as geothermal or waste heat below 100 °C. However, at these low temperatures, the effects of losses are proportionally higher due to the lower thermal potential available. One such significant loss is excess dead volume, wherein a significant contributor is the heat exchangers. The heat exchangers must be selected to optimize power output by minimizing the dead volume loss while maximizing the heat transfer to and from the engine. To better understand what the optimal geometry of the heat exchanger components is, a Stirling engine is modelled using a third-order commercial modelling software (Sage) and trends of engine properties of power, temperature, and pressure for different heat exchanger geometries are observed. The results indicate that there is an optimum heat exchanger volume and geometry for low temperature Stirling engines. This optimum is also affected by other engine properties, such as regenerator size and engine speed. These results provide insight into the optimal geometry of these components for low-temperature Stirling engines, as well as providing design guidance for future engines to be built.
Data reduction of friction factor, permeability and inertial coefficient for a compressible gas flow through a milli-regenerator
Authors: Dellali Emna , Lanzetta François , Begot Sylvie , Gavignet Eric , Rauch Jean-Yves
Published: October 2021

A regenerator of a Stirling machine alternately absorbs and releases heat from and to the working fluid which allows to recycle rejected heat during theoretical isochoric processes. This work focuses on a milli-regenerator fabricated with a multiple jet molding process. The regenerator is a porous medium filled with a dense pillar matrix. The pillars have a geometrical lens shape. Two metallic layers (chromium and copper) are deposited on the polymer pillars to increase heat transfer inside the regenerator. We performed experiments on different milli-regenerators corresponding to three porosities (ε = 0.80, 0.85 and 0.90) under nitrogen steady and oscillating compressible flows (oscillating Reynolds number in the range 0 < Reω < 60 and Reynolds number based on the hydraulic diameter ReDh,max<6000) for different temperature gradients (ΔT < 100°C). Temperature, velocity and pressure experimental measurements are performed with microthermocouples (type K with 7,6 µm diameter), hotwires and miniature pressure sensors, respectively. We identified a threeterm composite correlation equation for the friction factor based on a Darcy-Forchheimer flow model that best-fit the experimental data. In steady and oscillating flows permeabilities and inertial coefficients are of the same magnitude order. Inertial coefficients decrease when the porosities increase.