bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synergistic effect of sequential solvent treatment on the structural and low temperature charge transport of PEDOT:PSS films
Authors: Sharma Meenu , Bhatia Ravi , Sameera I 
Published: December 2022

Abstract
A detailed study on the low temperature charge transport and magnetoresistance (MR) measurements of spin-coated and solvent treated poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) films has been presented. The samples were prepared by sequential treatment of PEDOT:PSS film using dimethyl sulfoxide and sulphuric acid. X-ray diffraction and Raman spectroscopy elucidate the effect of solvent treatment on the structural modifications of the film, which correlates to the enhanced conductivity values. The nature of solvent and the sequence of successive treatments using different solvents has been effectively utilized to tune the conductivity of the film over a wide range. Further, the low temperature (300–2 K) charge transport study indicates that the resistance of the film rises sharply below 50 K, which implies the samples lie in the category of disordered materials. A linear fit of ln R vs. T
−1/4 for all the samples indicates that the temperature dependent resistance of solvent treated PEDOT:PSS films follow 3D variable range hopping model. The observed large positive MR behavior of the films has been discussed in terms of the wave function shrinkage of the charge carriers. The MR follows ∼B
2 and ∼B
1/3 dependence at low and high magnetic field regimes, respectively. The sequential treatment of PEDOT:PSS films shown in the present study is an effective method to enhance the electrical conductivity significantly.
Gradient expanded-structured graphene pressure sensor prepared by one-step laser reduction with superhigh sensitivity and ultrawide detection range
Authors: Lv Yuhuan , Qin Zhen , Fang Xiaohui , Zhao Biao , Liu Yong , Pan Kai 
Published: December 2022

Abstract
With the advancement of information data, intelligent devices have put forward higher performance requirements for pressure sensors. Reasonable structural design of active material provides an effective way for the preparation of high-performance pressure sensor. Herein, we propose a simple method to prepare gradient expandion-structured graphene-based flexible pressure sensors by laser reduction. There are many gas gaps exist under the graphene surface, showing a certain gradient as a whole. Benefiting from the synergy effect of the unique structure, the designed piezoresistive sensor shows high sensitivity (127.8 kPa−1 in the range of 0.33–0.667 kPa), broad linear range (0–16.7 kPa), low detection limit (33 Pa), short response time (200 ms), and good stability (more than 7000 cycles). Furthermore, the notion of creating and constructing gradient structures has been applied to practical applications of position sensing, and possible applications for mapping the position and intensity of pressure have also been investigated.
The Spectroscopic Classification of Astronomical Transients (SCAT) Survey: Overview, Pipeline Description, Initial Results, and Future Plans
Authors: Tucker M. A. , Shappee B. J. , Huber M. E. , Payne A. V. , Do A. , Hinkle J. T. , de Jaeger T. , Ashall C. , Desai D. D. , Hoogendam W. B. , Aldering G. , Auchettl K. , Baranec C. , Bulger J. , Chambers K. , Chun M. , Hodapp K. W. , Lowe T. B. , McKay L. , Rampy R. , Rubin D. , Tonry J. L. 
Published: December 2022

Abstract
We present the Spectroscopic Classification of Astronomical Transients (SCAT) survey, which is dedicated to spectrophotometric observations of transient objects such as supernovae and tidal disruption events. SCAT uses the SuperNova Integral-Field Spectrograph (SNIFS) on the University of Hawai’i 2.2 m (UH2.2m) telescope. SNIFS was designed specifically for accurate transient spectrophotometry, including absolute flux calibration and host-galaxy removal. We describe the data reduction and calibration pipeline including spectral extraction, telluric correction, atmospheric characterization, nightly photometricity, and spectrophotometric precision. We achieve ≲5% spectrophotometry across the full optical wavelength range (3500–9000 Å) under photometric conditions. The inclusion of photometry from the SNIFS multi-filter mosaic imager allows for decent spectrophotometric calibration (10%–20%) even under unfavorable weather/atmospheric conditions. SCAT obtained ≈640 spectra of transients over the first 3 yr of operations, including supernovae of all types, active galactic nuclei, cataclysmic variables, and rare transients such as superluminous supernovae and tidal disruption events. These observations will provide the community with benchmark spectrophotometry to constrain the next generation of hydrodynamic and radiative transfer models.
Effectively enhancing silicon-vacancy emission in a hybrid diamond-in-pit microstructure
Authors: Romshin Alexey M , Gritsienko Alexander V , Lega Peter V , Orlov Andrey P , Ilin Alexey S , Martyanov Artem K , Sedov Vadim S , Vlasov Igor I , Vitukhnovsky Alexei G 
Published: December 2022

Abstract
Solid-state photon emitters at room temperature appear to be promising candidates for a variety of nanophotonic applications. In this regard, coupling photon emitters with various optical cavities providing pronounced directivity, high photoexcitation and emission rates is extremely desirable. Here, we introduce the novel concept of deterministically coupling color centers in nanodiamonds (NDs) with gold nanopits. We show that in this case, emission of silicon-vacancy (SiV−) centers at the zero-phonon line can exceed that of a ND on a gold surface by a factor of 62. The obtained results reveal an effective pumping of the SiV-centers in NDs along with the active switching of the SiV-centers from the dark to the bright state by plasmon mode that opens the way to design controllable resonance systems with diamond-based photonic emitters.
The identification of interacting brain networks during robot-assisted training with multimodal stimulation
Authors: Wang Duojin , Huang Yanping , Liang Sailan , Meng Qingyun , Yu Hongliu 
Published: December 2022

Abstract

Objective. Robot-assisted rehabilitation training is an effective way to assist rehabilitation therapy. So far, various robotic devices have been developed for automatic training of central nervous system following injury. Multimodal stimulation such as visual and auditory stimulus and even virtual reality technology were usually introduced in these robotic devices to improve the effect of rehabilitation training. This may need to be explained from a neurological perspective, but there are few relevant studies. Approach. In this study, ten participants performed right arm rehabilitation training tasks using an upper limb rehabilitation robotic device. The tasks were completed under four different feedback conditions including multiple combinations of visual and auditory components: auditory feedback; visual feedback; visual and auditory feedback (VAF); non-feedback. The functional near-infrared spectroscopy devices record blood oxygen signals in bilateral motor, visual and auditory areas. Using hemoglobin concentration as an indicator of cortical activation, the effective connectivity of these regions was then calculated through Granger causality. Main results. We found that overall stronger activation and effective connectivity between related brain regions were associated with VAF. When participants completed the training task without VAF, the trends in activation and connectivity were diminished. Significance. This study revealed cerebral cortex activation and interacting networks of brain regions in robot-assisted rehabilitation training with multimodal stimulation, which is expected to provide indicators for further evaluation of the effect of rehabilitation training, and promote further exploration of the interaction network in the brain during a variety of external stimuli, and to explore the best sensory combination.
Effects of bootstrap current on magnetic configuration in Chinese first quasi-axisymmetric stellarator
Authors: Liu Haifeng , Zhang Jian , Xu Yuhong , Shimizu Akihiro , Cooper Wilfred Anthony , Okamura Shoichi , Isobe Mitsutaka , Wang Xianqu , Huang Jie , Cheng Jun , Liu Hai , Zhang Xin , Tang Changjian 
Published: December 2022

Abstract
Neoclassical properties in quasi-axisymmetric (QA) stellarators are analogous to these in tokamaks. Consequently, a substantial bootstrap current could significantly modify the MHD equilibrium properties of a QA stellarator, which is an important characteristic in this type of stellarator. This paper is dedicated to systemically investigate the effects of bootstrap current on the magnetic configuration in Chinese first quasi-axisymmetric stellarator (CFQS). For the first time, self-consistent bootstrap currents in free-boundary equilibria are calculated with an accurate Fokker–Planck neoclassical numerical mode in CFQS. Several important results are achieved: (a) as the bootstrap current grows with increasing volume-averaged normalized pressure

β

, magnetic shear develops in the bulk plasma and meanwhile, a deep magnetic well is robustly sustained, which leads to improved stabilization of interchange modes up to

β
∼
2.0

%

. (b) In the analysis of global ideal MHD instability, as the bootstrap current rises to 39 kA (

β
∼
1.3

%

), external kink modes become destabilized and the unstable mode with m/n = 2/1 is dominant. (c) From

β
=
0

to 1.5%, the bootstrap current hardly changes the QA property and a low neoclassical transport is maintained. However, as

β

is enhanced beyond 2.0%, the substantial bootstrap current gives rise to an increase of non-QA magnetic field components, which weakens the neoclassical transport properties. (d) An increase of the negative magnetic shear at the core region by the bootstrap currents has a favorable effect on the properties of J (second adiabatic invariant). The maximum-J region can be extended by raising bootstrap currents.
Global gyrokinetic simulation of edge coherent mode in EAST
Authors: Xie Baoyi , Ye Lei , Chen Yang , Zhao Pengfei , Ye Yang , Lin Xin , Lan Heng , Guo Wenfeng , Xiang Nong 
Published: December 2022

Abstract
Linear and nonlinear simulations are carried out for the edge coherent mode (ECM) using the global gyrokinetic code GEM based on the EAST experimental parameters. The linear simulation results show that ECM is an electrostatic mode with dominant toroidal mode number n = 18 and frequency about 48 kHz, and propagates along the direction of electron diamagnetic drift, which are consistent with the experimental results. In addition, the density and electron temperature gradients destabilize the mode, while the collision stabilizes the mode. The nonlinear simulation results show that the saturated particle and heat fluxes induced by ECM are mainly due to the perturbed electrostatic ExB drift, and the fluxes of electrons and ions are almost equal. The ECM drives significant outward particle and heat fluxes, thus greatly promoting the maintenance of the long pulse H-mode. The Fourier decomposition of fluxes and potentials demonstrate that the intermediate-n modes of n = 14, 18 grow fastest in the linear phase, while in the nonlinear saturation phase, the low-n modes such as n = 4, 6 dominate and the fluxes are mainly contributed by the mode of n = 10. It is found that zonal flow is not the dominant saturation mechanism of the turbulence. The inverse spectral cascade of turbulence is inevitably observed in the nonlinear saturation process, indicating that it is a more universal turbulence saturation mechanism. It is also found that radial electric field can greatly reduce the turbulence intensity and transport level. From the analyses of frequency and transport channels, it can be concluded that ECM appears to be the collisionless trapped electron mode.
Research on crowd dynamic risk management based on the psychological stress perception function
Authors: Ma Jun , Wang Meiling , Li Linze 
Published: December 2022

Abstract
Number of people, density and so on are often used as a risk indicator in crowd dynamic risk management, but crowd size cannot truly reflect the change process of psychological stress perception that leads to crowd behavior disorder. Therefore, this research calculates risk index thresholds from the perspective of psychological stress perception to help managers assess crowd-gathering risks. On the one hand, the behavior model and psychological stress perception model are constructed based on corresponding experiments at the micro layer. On the other hand, risk decision models, including the average density and phubbers ratio, are built at the macro level. Finally, a long subway transfer channel was used as a simulation scenario, and the critical value of the decision quantity was determined by taking the psychological stress perception of the crowd as the objective function. The simulation shows that the perceived pressure of the crowd changes nonlinearly with time. The simulation result of the critical threshold can be divided into four zones, namely, the safety area, warning area, disposal area and dangerous area, so that managers can take targeted measures. The results are validated by applying psychological stress perception to practical population risk management.
Dynamic Modelling of a Heat Exchanger Network for a Dairy Plant
Authors: Casadei Riccardo , Lorenzini Marco , Fattini Daniele , Valdiserri Paolo 
Published: December 2022

Abstract
In co-and trigeneration plants with internal combustion engines, waste heat from their cooling system can be fed to a heat exchanger network for office heating, hot water production, or used in industrial processes. At the same time, care must be exerted not to cool the return fluid below a threshold, in order to avoid piston seizure. In this work, the heat exchanger network is that of a gas-engine trigeneration system for a large dairy plant in Rome. Since its daily and weekly production schedule is subject to several changes, temperature control must be both precise and efficient. A thermal-hydraulic, dynamic (i.e. time-dependent) model of the heat exchanger network was developed in Matlab/Simulink, to obtain the instantaneous pressure, mass flowrate and temperature of the fluids along the network. The approach is mixed, a lumped-parameter description of the hydraulic and thermal networ, and finite volumes for the heat exchangers. The model has been verified and validated with experimental, steady-state data from the dairy plant and the results found satisfactory.
A Methodology to identify appropriate refurbishment strategies towards zero energy buildings in a hot and humid climate
Authors: Austin Miguel Chen , Carpino Cristina , Mora Dafni , Arcuri Natale 
Published: December 2022

Abstract
Significant actions on the building stock are required to reduce energy consumption and emissions from buildings and achieve carbon neutrality by 2050. Consistently, the renovation approach of existing buildings could aim to obtain nearly Zero Energy Buildings or Net Zero Energy Buildings (NZEB). In particular, the solutions to obtain zero-energy buildings vary according to the reference climatic conditions and the technical-constructive characteristics of the buildings undergoing renovation. As part of a research project involving the Technological University of Panama (UTP) and the University of Calabria (UNICAL), this work presents a preliminary investigation aimed at identifying the most appropriate technological solutions to convert existing buildings in Panama into zero-energy buildings. In particular, the study seeks to characterize the energy demand of buildings in the research area, consisting of Panama City, and to identify a set of possible energy efficiency measures applicable in hot and humid climates through dynamic simulations. The preliminary results from the sensitivity and optimization analyses highlight the capacity of local regulations and buildings’ capacity towards achieving zero-energy buildings by enhancing the efficiency of appliances, lighting, and air conditioner system, but also by implementing passive strategies such as the bioclimatic strategies.
Design and partial-load operation of a reversible Solid Oxide Cell system with molten salts thermal storage
Authors: Ficili Marco , Colbertaldo Paolo , Guandalini Giulio , Campanari Stefano 
Published: December 2022

Abstract
The increasing penetration of renewable energy sources in the electricity mix requires efficient storage solutions on the seasonal scale. Reversible Solid Oxide Cell (rSOC) systems are receiving increased attention as viable options to fulfil this requirement. In this work, a MW-scale rSOC system capable of working over a large operating window is studied via modelling on Aspen Plus®. To ease the thermal integration, a molten salt thermal storage is coupled to the system, enabling heat recovery in fuel cell mode, which is then exploited for water evaporation in electrolysis mode. The rSOC stack is designed to operate exothermically in the electrolysis mode at nominal load. In both modalities, the air mass flow rate is regulated to control the stack temperature, while limiting the in-out gradients within 100°C. At nominal load, the system achieves an electrical efficiency of 52% in fuel cell mode and of 87% in electrolysis mode. The operation at low partial loads, due to the decrease of the air flow rate, requires an additional high-temperature heat source to guarantee the heat integration. In this regard, the adoption of an electrical resistance in electrolysis mode and a hydrogen-fed combustor in fuel cell mode are selected as viable solutions to amplify the operating range of the system. As a results, the system can be operated down to the 30% of the stack nominal power in both modalities, where the system achieves an electric efficiency of 44% and 80% in fuel cell and electrolysis mode, respectively.
Thermo-physical properties of paraffin wax with iron oxide nanoparticles as phase change material for heat storage applications
Authors: Jebali Meriem , Colangelo Gianpiero , Haurie Laia , Bekri-Abbes Imene , Lacasta Ana Maria 
Published: December 2022

Abstract
Phase change materials (PCMs) are growing in importance in many thermal applications as heat storage or to smooth the energy peak demand in many technological fields in industrial as well as in civil applications. Conductive nanoparticles can be added to phase change material to improve their thermo-physical properties. In this work, Iron oxide nanoparticles (IOx-NPs) were synthesized using a simple and green synthesis method, free of toxic and harmful solvents, using the extract of a plant as a reducer and stabilizer at two different temperatures of calcination 500°C and 750°C. The metallic oxide was used as an additive with 2% wt. compositions to paraffin wax to prepare a nanocomposite. The variation in thermal properties of paraffin wax in the composite was experimentally investigated. The biosynthesized IOx-NPs were characterized by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM) and Thermal Gravimetric Analysis (TGA) techniques. The thermal properties of the synthesized nanocomposites were characterized by a thermal conductivity analyzer and differential scanning calorimetry (DSC). The FTIR spectra showed a bond at 535 cm-1, which confirms the Fe-O vibration. The XRD powder analysis revealed the formation of the cubic phase of Fe3O4 with an average particle size of 11 nm at 500°C and the presence of the phase α-Fe2O3 with Fe3O4 at 750°C. Scanning Electron Microscopy (SEM) showed that the obtained oxide was made up of particles of nanoscale size. Experimental measurements showed that the presence of nanoparticles can improve the latent heat capacity by a maximum of 16.16 % and the thermal conductivity of the nanocomposites by a maximum of 16.99%.
Downsizing the electric machines of energy-efficient electro-hydraulic drives for mobile hydraulics
Authors: Padovani D , Fresia P , Rundo M , Altare G 
Published: December 2022

Abstract
The poor energy efficiency of state-of-the-art mobile hydraulics affects the carbon dioxide released into the atmosphere and the operating costs. These crucial factors require urgent improvements that can be addressed by the electrification of fluid power. This approach has already generated electro-hydraulic drives that remove flow throttling and enable energy recovery. However, the entire power managed by the actuators of conventional systems must pass through the electric machines. This characteristic is unfeasible for medium-to-high power applications since they need electric motors and electronics with high power ratings and large onboard generation of electricity. Thus, this paper applies to a hydraulic excavator’s boom the idea of splitting the power being transferred to/from the actuator between the hydraulic and electric domains (i.e., a centralized hydraulic power supply is involved). The objective is downsizing the power rating of the boom’s electric components while maintaining the high-power output of the hydraulic actuator. The results show the expected behavior of the hybrid excavator in terms of motion control, but only 57% of the boom’s peak power is now exchanged electrically. The resulting electric machine with 61% downsizing favors the system’s cost and compactness supporting the electrification process that is aligned with the low-carbon economy.
Life Cycle Analysis of a Hydrogen Valley with multiple end-users
Authors: Concas Giulia , Cocco Daniele , Lecis Lorenzo , Petrollese Mario 
Published: December 2022

Abstract
This paper aims to evaluate the environmental impact along the overall life cycle of the various components of a Hydrogen Valley with multiple end-users fed by green hydrogen. As case study, a hydrogen valley including a MW-scale electrolyser powered by different percentages of energy supplied by a wind farm and/or a photovoltaic plant, and an H2 storage section is considered. The H2 produced is used to feed a fleet of fuel cell electric vehicles and a stationary fuel cell, while the residue H2 is injected in a natural gas pipeline considering a maximum safety limit of 5%vol. When the safety limit is reached, the H2 overproduction can be used to produce biomethane through a biological hydrogen methanation process. With the aim of analysing the actual contribution of these hydrogen-based ecosystems towards more sustainable energy systems, a Life Cycle Analysis of the hydrogen valley is carried out. The results show that the final use of hydrogen for fuel cell electric vehicles produces the most valuable environmental benefits. Moreover, Hydrogen Valley solutions integrated with photovoltaic plants allows to maximize the use of H2 in fuel cell electric vehicles and therefore are the most valuable choice from an environmental point of view.