bluuebunny/crossref_metadata_2025_split huggingface dataset:
Three-dimensional composite electrospun nanofibrous membrane by multi-jet electrospinning with sheath gas for high-efficiency antibiosis air filtration
Authors: Jiang Jiaxin , Shao Zungui , Wang Xiang , Zhu Ping , Deng Shiqing , Li Wenwang , Zheng Gaofeng 
Published: March 2021

Abstract
Three-dimensional (3D) composite polyvinylidene fluoride (PVDF)/polyacrylonitrile (PAN) electrospun nanofibrous membranes combining both thick and thin nanofibers have been fabricated by the method of multi-jet electrospinning with sheath gas to realize high-efficiency air filtration under a low pressure drop. The thin PAN nanofibers form a dense membrane, with a strong capturing ability on the ultra-fine particles, while the thick PVDF nanofibers play a 3D supporting effect on the thin PAN nanofibers. In this case, the combination results in a fluffy membrane with higher porosity, which could achieve the airflow passing through the membrane without the air pressure drop. The effects of the composite manner of thick nanofibers and thin nanofibers are investigated, in order to optimize the air filtration performance of the 3D composite nanofibrous membrane. As a result, the maximum quality factor for air filtration could reach up to 0.398 Pa−1. The particle-fiber interaction model was used to simulate the air filtration process as well, and the simulation results were fairly consistent with the experimental results, providing a guidance method for the optimization of composite nanofibrous membrane for high-efficiency air filtration. More interestingly, a cationic poly[2-(N,N-dimethyl amino) ethyl methacrylate] (PDMAEMA) was added in the PVDF solution to obtain a composite air filtration membrane with excellent antibiosis performance, which achieved the highest inhibition rate of approximately 90%. In short, this work provides an effective way to promote antibiosis air filtration performance by using an electrospun nanofibrous membrane, and might also effectively accelerate the biological protection application of current air filtration membranes.
Metallo-deuteroporphyrins derived multi-layered hollow carbon spheres electrocatalysts for highly efficient oxygen reduction reaction
Authors: Zhang Han , Wang Yue , Liu Shaojun , Li Chenglong , Li Lixiang , An Baigang , Sun Chengguo 
Published: March 2021

Abstract
The development of low-cost, highly efficient and stable non-precious metal electrocatalyst for the oxygen reduction reaction (ORR) substituting Pt has attracted much attention. Herein, we developed a promising structural platform for the fabrication of carbon nanospheres functionalized with hollow nanostructures of M-NHCS (M = Fe, Co and Mn) based on metallo-deuteroporphyrins (MDP). Benefited from the multi-layered active sites and hollow substrate with more exposed active surface area, convenient channels for the transport of electrons, the resulting Fe-NHCS electrocatalysts exhibit enhanced electrocatalytic performance in ORR with an onset potential of 0.90 V (versus RHE), and a high selectivity in the direct 4-electron pathway. The Fe-NHCS electrocatalysts also show a good methanol tolerance superior to Pt/C catalysts and an extremely high stability with only 13.0 mV negative after 5000 cycles in alkaline media. Experiments have verified that maintaining the multi-layered Fe−N−C active sites and hollow substrate were essential to deliver the high performance for ORR. The work opens new avenues for utilizing MDP-based materials in future energy conversion applications.
A robotically assisted 3D printed quality assurance lung phantom for Calypso
Authors: Capaldi Dante P I , Skinner Lawrie B , Dubrowski Piotr , Zhang Hao , Xing Lei , Chuang Cynthia F , Loo Billy W , Bush Karl K , Fahimian Benjamin P , Yu Amy S 
Published: March 2021

Abstract

Purpose. Radiation dose delivered to targets located near the upper-abdomen or in the thorax are significantly affected by respiratory-motion. Relatively large-margins are commonly added to compensate for this motion, limiting radiation-dose-escalation. Internal-surrogates of target motion, such as a radiofrequency (RF) tracking system, i.e. Calypso® System, are used to overcome this challenge and improve normal-tissue sparing. RF tracking systems consist of implanting transponders in the vicinity of the tumor to be tracked using radiofrequency-waves. Unfortunately, although the manufacture provides a universal quality-assurance (QA) phantom, QA-phantoms specifically for lung-applications are limited, warranting the development of alternative solutions to fulfil the tests mandated by AAPM’s TG142. Accordingly, our objective was to design and develop a motion-phantom to evaluate Calypso for lung-applications that allows the Calypso® Beacons to move in different directions to better simulate true lung-motion. Methods and Materials. A Calypso lung QA-phantom was designed, and 3D-printed. The design consists of three independent arms where the transponders were attached. A pinpoint-chamber with a buildup-cap was also incorporated. A 4-axis robotic arm was programmed to drive the motion-phantom to mimic breathing. After acquiring a four-dimensional-computed-tomography (4DCT) scan of the motion-phantom, treatment-plans were generated and delivered on a Varian TrueBeam® with Calypso capabilities. Stationary and gated-treatment plans were generated and delivered to determine the dosimetric difference between gated and non-gated treatments. Portal cine-images were acquired to determine the temporal-accuracy of delivery by calculating the difference between the observed versus expected transponders locations with the known speed of the transponders’ motion. Results. Dosimetric accuracy is better than the TG142 tolerance of 2%. Temporal accuracy is greater than, TG142 tolerance of 100 ms for beam-on, but less than 100 ms for beam-hold. Conclusions. The robotic QA-phantom designed and developed in this study provides an independent phantom for performing Calypso lung-QA for commissioning and acceptance testing of Calypso for lung treatments.
The effect of Ag doping and point defects on the electronic structure and photocatalytic properties of ZnO using first-principles
Authors: Liu Yajing , Hou Qingyu 
Published: March 2021

Abstract
At present, the photocatalytic properties of Ag-doped ZnO have been extensively studied, but the mechanism of Ag-doped ZnO photocatalysis is not fully understood. The effect of intrinsic point defects on the performance and mechanism of Ag-doped ZnO photocatalysis has rarely been studied by theoretical calculations. To solve such problems, first-principle calculations were performed to systematically investigate the effect of Ag doping (AgZn/Agi) and point vacancy (VZn/VO) on the photocatalytic performance and mechanism of ZnO. It was found that the ZnO:Agi+VZn showed the strongest structural stability compared to the three doping methods, ZnO:AgZn+VZn, ZnO:AgZn+VO, and ZnO:Agi+VO. In addition, the doping of interstitial Ag with Zn vacancy shrank the ZnO bandgap to the smallest bandgap width (2.46 eV), thereby broadening the ZnO absorption spectrum into the visible range. The study of the dipole moment, static dielectric constant, and carrier effective mass showed that the ZnO:Agi+VZn exhibited excellent photocatalytic polarization and activity in the visible range. In particular, along the [001] direction, electrons and holes showed stronger mobility, resulting in effective separation and transfer of electron-hole pairs and a reduction in the electron-hole complex rate. The results provided a theoretical reference for in-depth understanding and designing of novel ZnO photocatalysts.
Physical and mechanical properties of ternary Ge-Se-Sb glasses for near-infrared applications
Authors: El-Denglawey A , Dahshan A , Aly K A , Saddeek Y B 
Published: March 2021

Abstract
Many physical properties such as the average coordination number (CN), the compactness (δ), the overall bond energy (〈E〉), the cohesive energy (CE), the mean bond energy (E
s), and the overall electronegativity difference (Δχ) as well as the degrees of ionicity (Ion) and covalency (Cov) were estimated theoretically. The chemical bond approach (CBA) was used to predict the type and proportion of the formed bonds in the studied glasses. Consequently, several structural and physical properties have been estimated. The results show that the studied glasses are rigidly connected, having an average coordination number increase from 2.41 to 2.61. Two approaches have been successfully used to estimate the band gap (E
g) theoretically compared with the previously published experimental values for the Ge18Se82−xSbx (5 ≤ x ≤ 25 at. %) glasses. Values of E
g decrease from 1.59 to 1.15 eV by an increase of the Sb content from 5 to 25 at. %. i.e. the wavelengths corresponding to E
g values lie in the near-infrared range of spectra, which make these glasses candidates for the near-infrared applications. Furthermore, the ultrasonic longitudinal (v

L
) and shear wave (v

T
) velocities propagating through the glasses have been used to estimate the mechanical parameters such as the elastic bulk modulus, Poisson’s ratio, Young’s modulus, micro-hardness, and temperature of Debye. It was found that a change in slope occurs for various physical, mechanical, and structural properties near the stoichiometric composition (x ≈ 18 at. %) at which the glass structure consists of heteropolar bonds only.
Validity of thermodynamic laws and weak cosmic censorship for AdS black holes and black holes in a cavity *
Authors: Wang Peng , Wu Houwen , Ying Shuxuan 
Published: March 2021

Abstract
By throwing a test charged particle into a Reissner-Nordstrom (RN) black hole, we test the validity of the first and second laws of thermodynamics and the weak cosmic censorship conjecture (WCCC) with two types of boundary conditions: the asymptotically anti-de Sitter (AdS) space and a Dirichlet cavity wall placed in an asymptotically flat space. For the RN-AdS black hole, the second law of thermodynamics is satisfied, and the WCCC is violated for both extremal and near-extremal black holes. For the RN black hole in a cavity, the entropy can either increase or decrease depending on the change in the charge, and the WCCC is satisfied/violated for the extremal/near-extremal black hole. Our results indicate that there may be a connection between the black hole thermodynamics and the boundary condition imposed on the black hole.
Effect of skull thickness and conductivity on current propagation for noninvasively injected currents
Authors: Forssell Mats , Goswami Chaitanya , Krishnan Ashwati , Chamanzar Maysamreza , Grover Pulkit 
Published: March 2021

Abstract

Objective. When currents are injected into the scalp, e.g. during transcranial current stimulation, the resulting currents generated in the brain are substantially affected by the changes in conductivity and geometry of intermediate tissue. In this work, we introduce the concept of ‘skull-transparent’ currents, for which the changing conductivity does not significantly alter the field while propagating through the head. Approach. We establish transfer functions relating scalp currents to head potentials in accepted simplified models of the head, and find approximations for which skull-transparency holds. The current fields resulting from specified current patterns are calculated in multiple head models, including MRI heads and compared with homogeneous heads to characterize the transparency. Experimental validation is performed by measuring the current field in head phantoms. Main results. The main theoretical result is derived from observing that at high spatial frequencies, in the transfer function relating currents injected into the scalp to potential generated inside the head, the conductivity terms form a multiplicative factor and do not otherwise influence the transfer function. This observation is utilized to design injected current waveforms that maintain nearly identical focusing patterns independently of the changes in skull conductivity and thickness for a wide range of conductivity and thickness values in an idealized spherical head model as well as in a realistic MRI-based head model. Experimental measurements of the current field in an agar-based head phantom confirm the transparency of these patterns. Significance. Our results suggest the possibility that well-chosen patterns of current injection result in precise focusing inside the brain even without a priori knowledge of exact conductivities of intermediate layers.
Two-dimensional resistive MHD simulation of the optimized plasma formation in the spherical tokamaks
Authors: Ahmadi T. , Tanabe H. , Ono Y. 
Published: March 2021

Abstract
We present 2D global MHD simulation results of the optimized start-up scenarios for the spherical tokamak to maximize the ion heating energy determined by the value of the poloidal private flux during the merging start-ups. The series of simulations has successfully revealed the dependence of the poloidal private flux on the in-vessel poloidal coils’ separation length under the fixed amount of coils’ magnetic energy. The radial and azimuthal locations of the internal coils need to be optimized to maximize high private flux and consequently high ion heating energy. In the case of a two poloidal field (PF) coils system, the private flux and ion heating energy increase with the coils’ separation length. Installing two additional PF coils improves the private flux significantly, even if the coils’ separation length is short.
Retraction: Detailed kinetic modeling of nitroglycerin low-temperature decomposition (J. Phys.: Conf. Ser.
1721 012002)
Authors: Glorian J , Baschung B 
Published: March 2021

This article is retracted at the request of the authors, who withdrew from this conference before the event and as such, should not have been included in the proceedings. The conference organisers apologise to the authors and IOP Publishing for this error. IOP Publishing have investigated according to COPE guidelines and agree the article should be retracted.
Retraction published: 03 March 20201
Capability of active thermography to detect and localize pores in Metal Additive Manufacturing materials
Authors: D’Accardi Ester , Ulbricht Alexander , Krankenhagen Rainer , Palumbo Davide , Galietti Umberto 
Published: March 2021

Abstract
Active thermography is a fast, contactless and non-destructive technique that can be used to detect internal defects in different types of material. Volumetric irregularities such as the presence of pores in materials produced by the Additive Manufacturing processes can strongly affect the thermophysical and the mechanical properties of the final component. In this work, an experimental investigation aimed at detecting different pores in a sample made of stainless AISI 316L produced by Laser Powder Bed Fusion (L-PBF) was carried out using pulsed thermography in reflection mode. The capability of the technique and the adopted setups in terms of geometrical and thermal resolution, acquisition frequency and energy density of the heating source were assessed to discern two contiguous pores as well as to detect a single pore. Moreover, a quantitative indication about the minimum resolvable pore size among the available and analysed defects was provided. A powerful tool to assess the limits and the opportunities of the pulsed technique in terms of detectability and localizability was provided by comparing active thermography results to Computed Tomography as well as a related Finite Element Analysis (FEA) to simulate the pulsed heating transfer with Comsol.
Ultrasonic and thermographic fatigue monitoring on a full-scale CFRP aeronautical component after repairing
Authors: Dattoma V , Nobile R , Palano F , Panella F W , Pirinu A , Saponaro A 
Published: March 2021

Abstract
The identification of defects in real components made in composite material assumes considerable importance in the aeronautical field, as irregularities in the material can compromise its functionality. Also, the possibility (NDT) to verify the effectiveness of repairing on the component during exercise through non-destructive testing techniques has great importance.
The goal of the present study is the application of the ultrasound and thermographic techniques for the identification of defects in a repaired component and the evaluation of the damage caused by the application of cyclical fatigue loads. All the important factors were studied, improving ultrasound scanning and allowing evaluating the effectiveness of the techniques used. In this paper, one case of study was proposed for non-destructive damage evaluation employing Phased Array ultrasonic and thermographic methods on aeronautical CFRP component. The structural element analysed is a spar with a double-T section with a hole and presents a repair by scarfing and hot bond process. The experimental results obtained shown the validity of the ultrasonic and thermographic technique for the sensitivity in detecting defects on full-scale aeronautical components with short execution and scan times.
An experimental-numerical methodology for the nondestructive assessment of the dynamic elastic properties of adhesives
Authors: Tridello A , Ciardiello R , Paolino DS , Goglio L 
Published: March 2021

Abstract
In the last years, lightweight design has become a priority in many industrial sectors, like as the aerospace and the automotive industry, mainly due to the strict regulations in terms of gas emission and pollution. Together with lightweight materials, the use of adhesives to join different parts permits to significantly reduce the weight of mechanical assemblies. For a proper design of the joints, the mechanical properties of adhesives should be correctly experimentally assessed. However, the experimental assessment of the adhesive mechanical properties can be complex, since they can be hardly estimated from traditional experimental tests on lap-joint or butt-joint specimens. The development of an experimental procedure for the assessment of the adhesive properties is therefore of interest. In the present paper, a methodology for the assessment of the dynamic elastic properties of adhesives, i.e., Young’s modulus and the loss factor, is proposed. The procedure is based on the Impulse Excitation Technique and Finite Element Analyses (FEA). An automated routine has been written to assess the elastic properties by minimizing the difference between the frequency response obtained experimentally and through FEA. The proposed methodology has been experimentally validated to estimate the mechanical properties of an epoxy adhesive for automotive applications.
Influence of SLM parameters on the compressive behaviour of lattice structures in 17-4PH stainless steel
Authors: Bertocco A , Esposito L , Aurino A , Borrelli D , Caraviello A 
Published: March 2021

Abstract
Additive manufacture (AM) technologies allow innovative structural design, including complex lattice structures. Selective laser melting (SLM) is an AM process that enables the manufacture of space filling lattice structures. Lattice structures are topologically ordered, three-dimensional open-celled structures composed of one or more repeating unit cells. From a mechanical designer viewpoint, a great advantage offered by cellular materials is high strength accompanied by a relatively low mass. Due to their complex structure, fine geometry and the absence of supports structures, the setting of the best parameters to print lattice structures is difficult and could negative influence their mechanical response. This study investigated how different parameters settings influence the compression behaviour of lattice structures in stainless steel 17-4PH (AISI-630) printed by SLM. A comparison between compressive response of structures printed with different parameters is presented and considerations about their behaviour exposed.
Laser shock composite microforming of Fe-based amorphous alloys
Authors: Gu Xin , Wang Xiao , Cui Jiankun , Ma Youjuan , Zhang Haokun , Wang Keyang , Lu Jiaxin 
Published: March 2021

Abstract
To address the shortcomings of Fe-based amorphous alloys that are difficult to plastically form at room temperature, this study used high strain rate laser instead of traditional loading methods to conduct composite microforming of drawing, punching, and blanking. This article mainly explored the influence of laser energy and soft film thickness on the forming accuracy and depth, morphological characteristics, thickness distribution and mechanical properties. Result showed that the forming accuracy increased with the increase in the laser energy. However, the forming depth decreased when the laser energy was large. The forming accuracy was good when the soft film thickness was small. Abundant shear bands were distributed on the surface, indicating that the plastic deformation was realized on the basis of the generation and propagation of the shear bands. The cross-sectional morphology was also composed of smooth and choroid regions, and their composition ratio also varied in different regions. The bottom region had the smallest thickness, and the flange region had the largest thickness. The distribution of the nanohardness on cross-section was roughly the same as that of the workpiece thickness. The nanohardness was small when the thickness was thin. The elastic modulus gradually decreased from the flange region to the bottom region.
Preparation of black phosphorus coatings with photo-thermal conversion properties
Authors: Liu Hehuan , Shi Yunbo , Tang Bolun , Wang Tian , Zhang Huanhuan 
Published: March 2021

Abstract
Black phosphorus (BP) is a semiconductor material with excellent optical properties. To explore a more convenient method for preparation bulk BP and facilitate new applications of BP in engineering field, we used a single-zone tube furnace to fabricate bulk BP using tin and iodine as mineralisers. Further, a BP slurry with a uniform particle size was prepared by cutting the bulk BP in a solvent. BP coatings with different thicknesses were prepared, and their photo-thermal conversion properties were evaluated. The characterisation and test results showed that the BP coating was superimposed by BP flakes with an estimated plane size of ∼10 μm. The infrared absorptivity of the BP coatings was 87.83%–92.48%. The results clearly indicated that the BP coatings exhibit photo-thermal conversion properties that can be exploited for various applications.
Efficient dye discoloration of modified Lamiaceae leaves
Authors: Aljohani Meshari M H , Almizraq Jassim M J , Albalawi Abdulrahman M , Alshammari Almathna S A , Albalawi Nader O S , Albalawi Abdulrahman N S A , Alatwi Qasem A Q , Keshk Ali A , Althaqafy Adel D , Al-Aoh Hatem A 
Published: March 2021

Abstract
The powder of Lamiaceae Leaves was modified by Zinc Chloride (ZnCl2). The Chemical Modified Lamiaceae Leaves Powder (CMLLP) was characterized by BET surface analyzer, FTIR, SEM and Theydan and Ahmed method. It was found that this adsorbent has pHZPC of 6.2, surface area of 104.78 m2g−1, pore volume of 0.00464 cc/g and average pore diameter of 2647.813 Å. This sorbent was used as a cheap adsorbent for the extraction of Methylene Blue (MB) from contaminated solutions. The effect of temperature, pH of solution, time of contact and MB primary concentration were also investigated. All of these variables have positive impacts on this adsorption. The data obtained from the isotherm’s experiments, were analysed using three models. The obtained results confirmed that model of Langmuir was the most efficient. The capacities of this adsorption were found to be 333.33, 384.62, 434.78 and 476.19 mg g−1 at 25, 35, 45 and 60 °C, correspondingly. Three models of kinetic were applied to determine the constants of this adsorption kinetics. It was observed that the kinetic results follow the 2nd order more than the other two kinetic models. Moreover, thermodynamic constants were determined, which showed that this adsorption is an exothermic and spontaneous process.