bluuebunny/crossref_metadata_2025 huggingface dataset:
Agile, Easily Applicable, and Useful eHealth Usability Evaluations: Systematic Review and Expert-Validation
Authors: Sinabell Irina , Ammenwerth Elske
Published: March 2022

Background Electronic health (eHealth) usability evaluations of rapidly developed eHealth systems are difficult to accomplish because traditional usability evaluation methods require substantial time in preparation and implementation. This illustrates the growing need for fast, flexible, and cost-effective methods to evaluate the usability of eHealth systems. To address this demand, the present study systematically identified and expert-validated rapidly deployable eHealth usability evaluation methods.

Objective Identification and prioritization of eHealth usability evaluation methods suitable for agile, easily applicable, and useful eHealth usability evaluations.

Methods The study design comprised a systematic iterative approach in which expert knowledge was contrasted with findings from literature. Forty-three eHealth usability evaluation methods were systematically identified and assessed regarding their ease of applicability and usefulness through semi-structured expert interviews with 10 European usability experts and systematic literature research. The most appropriate eHealth usability evaluation methods were selected stepwise based on the experts' judgements of their ease of applicability and usefulness.

Results Of these 43 eHealth usability evaluation methods identified as suitable for agile, easily applicable, and useful eHealth usability evaluations, 10 were recommended by the experts based on their usefulness for rapid eHealth usability evaluations. The three most frequently recommended eHealth usability evaluation methods were Remote User Testing, Expert Review, and Rapid Iterative Test and Evaluation Method. Eleven usability evaluation methods, such as Retrospective Testing, were not recommended for use in rapid eHealth usability evaluations.

Conclusion We conducted a systematic review and expert-validation to identify rapidly deployable eHealth usability evaluation methods. The comprehensive and evidence-based prioritization of eHealth usability evaluation methods supports faster usability evaluations, and so contributes to the ease-of-use of emerging eHealth systems.
Perinatal Carbon Monoxide Poisoning: Treatment of a 2-Hour-Old Neonate with Hyperbaric Oxygen
Authors: Kreshak Allyson A. , Lawrence Shelley M. , Ontiveros Sam T. , Castellano Tiffany , VanHoesen Karen B.
Published: March 2022

A 41-year-old gravida 4 para 3 (G4P3) and 385/7 weeks pregnant woman presented to labor and delivery with dizziness, headache, and decreased fetal movement after 12 hours of exposure to carbon monoxide (CO) from a grill that was used inside for heat. The mother was hemodynamically stable, and her neurologic examination was intact. Her carboxyhemoglobin level, which was obtained 12 hours after removal from the CO exposure, was 7.4%. The fetus's heart rate was 173 beats per minute with moderate variability and one late appearing deceleration, not associated with contractions. The biophysical profile score was 2 of 8. The obstetrics team performed a routine cesarean section. The 1- and 5-minute Apgar's scores were 7 and 8, respectively. The arterial cord gas result was as follows: pH = 7.05, PCO2 = 71 mm Hg, pO2 = 19 mm Hg, bicarbonate = 14 mmol/L, and carboxyhemoglobin = 11.9%. The mother and infant were treated with hyperbaric oxygen therapy consisting of 100% oxygen at 2.4 atmosphere absolutes (ATA) for 90 minutes at 2.5 hours after delivery. Following one hyperbaric oxygen treatment, the infant was transitioned to room air and routine postpartum treatment and was discharged 3 days later in good condition. Hyperbaric oxygen treatment was well tolerated in this neonate.
Hybrid plasma simulations of a magnetically shielded Hall thruster
Authors: Perales-Díaz J. , Domínguez-Vázquez A. , Fajardo P. , Ahedo E. , Faraji F. , Reza M. , Andreussi T.
Published: March 2022

Numerical simulations of a magnetically shielded Hall effect thruster with a centrally mounted cathode are performed with an axisymmetric hybrid particle-in-cell/fluid code and are partially validated with experimental data. A full description of the plasma discharge inside the thruster chamber and in the near plume is presented and discussed, with the aim of highlighting those features most dependent on the magnetic configuration and the central cathode. Compared to traditional magnetic configurations, the acceleration region is mainly outside the thruster, whereas high plasma densities and low temperatures are found inside the thruster. Thus, magnetic shielding does not decrease plasma currents to the walls, but reduces significantly the energy fluxes, yielding low heat loads and practically no wall erosion. The injection of neutrals at the central cathode generates a secondary plasma plume that merges with the main one and facilitates much the drift of electrons toward the chamber. Once inside, the magnetic topology is efficient in channeling electron current away from lateral walls. Current and power balances are analyzed to assess performances in detail.
Subcycle terahertz field waveforms clocked by attosecond high-harmonic pulses from relativistic laser plasmas
Authors: Glek P. B. , Zheltikov A. M.
Published: March 2022

A high-intensity ultrashort laser pulse interacting with a thin plasma target is shown to couple to plasma electrons, driving electron oscillations within the plasma and making these electrons bounce back and forth between plasma boundaries. Each time these recirculating electrons traverse the plasma boundary, they emit bright subcycle terahertz (THz) field waveforms via laser-driven coherent transition radiation. As a concurrent process, laser-driven electrons near the front surface of the plasma target are accelerated to relativistic velocities to emit high-order harmonics (HHs), giving rise to attosecond pulses of vacuum-ultraviolet radiation. These attosecond pulses are shown to provide a high-precision clock for subcycle THz field waveforms. We demonstrate that the delay time between HH pulses and THz waveforms can be tuned with an attosecond precision by varying the thickness of the plasma target, thus opening an avenue toward HH-pump–THz-probe studies of ultrafast processes on the attosecond time scale with table-top laser sources.
Microwave techniques for electron cyclotron resonance plasma diagnostics
Authors: Mascali David , Naselli Eugenia , Torrisi Giuseppe
Published: March 2022

This paper reviews the main microwave diagnostic techniques and tools adopted in electron cyclotron resonance (ECR) (and others) ion source laboratories, with a special focus on techniques and instruments developed at INFN-LNS. Along with the tools used for optimization of microwave launching (power monitors, spectral analysis, and network analyzers), this paper deals, in particular, with more recent devices on-purpose developed to perform in-plasma analysis, such as absolute density measurements and density profiles retrieval. Among these, the first example of microwave interferometry for ECR compact machines (the VESPRI interferometer at INFN-LNS) will be briefly discussed, in combination with microwave polarimetric techniques based on Faraday rotation detection. More sophisticated microwave techniques are going to be designed and are now at a numerical study stage, e.g., profilometry and imaging via inverse scattering methods (this paper will offer short theoretical bases and first numerical results on 1D profilometry). In the end, the relevance about the implications and interplays of microwave techniques in multidiagnostic systems (microwave, optical, and x-ray domains) will be commented, with a special focus on time resolved microwave measurements and advanced signal processing via wavelet transform, useful for characterization of plasma instabilities.
On the role of bandwidth in pump and seed light waves for stimulated Raman scattering in inhomogeneous plasmas
Authors: Luo Mufei , Hüller Stefan , Chen Min , Sheng Zhengming
Published: March 2022

The effects of incoherence on the three-wave coupling process of backward stimulated Raman scattering (SRS) in inhomogeneous plasmas are investigated theoretically and numerically via a three-wave coupling model. The impact of the plasma wave nonlinearity is taken into account, namely, the effect of trapped electrons via a nonlinear frequency shift of the electron plasma wave. Incoherence in the coupling is introduced in the seed wave, and the laser pump wave via bandwidth associated with a Lorentzian power spectrum. It is found that temporal incoherence can suppress the instability as long as the gain associated with spatial amplification in an inhomogeneous plasma (“Rosenbluth gain”) is smaller than 2. Otherwise, kinetic effects may destabilize SRS and significantly increase the backscatter level. For the bandwidth effects of the pump laser, a statistical analysis has been performed to examine the real impact of bandwidth. Moreover, a semi-analytical expression of the growth rate in the nonlinear stage is given. By estimating the bandwidth effects, it is found that a broad bandwidth of the pump laser starts to mitigate the scattering provided that the laser beam coherence time τc is shorter than γ0−1, the inverse of the standard SRS growth rate γ0. However, to obtain effective mitigation, by maintaining SRS in an almost linear stage, it is found that the criterion γ0τc≤0.35 has to be fulfilled.
Quantum Rajeev–Ranken model as an anharmonic oscillator
Authors: Krishnaswami Govind S. , Vishnu T. R.
Published: March 2022

The Rajeev–Ranken (RR) model is a Hamiltonian system describing screw-type nonlinear waves of wavenumber k in a scalar field theory pseudodual to the 1 + 1D SU(2) principal chiral model. Classically, the RR model is Liouville integrable. Here, we interpret the model as a novel 3D cylindrically symmetric quartic oscillator with an additional rotational energy. The quantum theory has two dimensionless parameters. Upon separating variables in the Schrödinger equation, we find that the radial equation has a four-term recurrence relation. It is of type [0, 1, 16] and lies beyond the ellipsoidal Lamé and Heun equations in Ince’s classification. At strong coupling λ, the energies of highly excited states are shown to depend on the scaling variable λk. The energy spectrum at weak coupling and its dependence on k in a double-scaling strong coupling limit are obtained. The semi-classical Wentzel-Kramers-Brillouin (WKB) quantization condition is expressed in terms of elliptic integrals. Numerical inversion enables us to establish a (λk)2/3 dispersion relation for highly energetic quantized “screwons” at moderate and strong coupling. We also suggest a mapping between our radial equation and the one of Zinn-Justin and Jentschura that could facilitate a resurgent WKB expansion for energy levels. In another direction, we show that the equations of motion of the RR model can also be viewed as Euler equations for a step-3 nilpotent Lie algebra. We use our canonical quantization to uncover an infinite dimensional reducible unitary representation of this nilpotent algebra, which is then decomposed using its Casimir operators.
Quasi-one-dimensional van der Waals TiS3 nanosheets for energy storage applications: Theoretical predications and experimental validation
Authors: Patra Abhinandan , Kapse Samadhan , Thapa Ranjit , Late Dattatray J. , Rout Chandra Sekhar
Published: March 2022

To cease the ever-increasing energy demand, additional enthusiastic focus has been given to generate more sustainable energy from alternative renewable sources. Storage of these energies for future usage solely banks on energy storage devices. A diversity of electrode materials based on two-dimensional (2D) transition metals and their derivatives have enticed the whole world owing to their tunable properties. Transition metal trichalcogenides (MX3 type) are the emergent class of 2D materials, which gathered a lot of interest because of their quasi-one-dimensional anisotropic properties with the van der Waals force of attraction in between the layers. Herein, TiS3 being a MX3-type of material is preferred as the battery type-supercapacitor electrode for energy storage applications with detailed theoretical predications and experimental validations. The highest capacitance attained for TiS3 is found to be 235 F/g (105 C/g) at 5 mV/s with a battery type of charge storage mechanism. The asymmetric hybrid device is fabricated using Ti3C2Tx MXene nanosheets as a negative electrode, and a brilliant 91% of capacitance retention is accomplished with an extensive potential window of 1.5 V. The investigational discoveries are substantiated by theoretical simulation in terms of the quantum capacitance assessment and charge storage mechanisms.
Effects of underwater explosion depth on shock wave overpressure and energy
Authors: Gao Yuan , Wang Shushan , Zhang Jingxiao , Jia Xiyu , Liang Ce , Ma Feng
Published: March 2022

In this paper, the effects of the water depth on the overpressure (pressure difference between positive shock pressure and hydrostatic pressure) peak and energy of underwater explosion shock waves were analyzed. Two quantitative calculation models were established that accounted for the effect of the water depth, which have theoretical and practical engineering value. A simulated deepwater explosion tank test was first conducted to obtain experimental data of the overpressure peaks and energies of the explosion shock waves generated by 10 and 30 g trinitrotoluene (TNT) explosives in a simulated environment at water depths of 400, 500, and 600 m. A one-dimensional wedge-shaped Euler grid numerical model was established to simulate the underwater explosion using the Autodyn software. The simulation model was validated by the experimental data to prove its accuracy and rationality. Then, numerical simulations were carried out at 13 operating conditions with 30 g of TNT in a full water depth range of 0–5000 m. Based on the simulation data analysis, the calculation models of the overpressure peak and energy flow density of the underwater explosion shock wave were obtained, which contain water depth correction functions. The results show that both the overpressure peak and the shock wave energy decreased with increase in the water depth, but the reduction percentage of the overpressure peak with the water depth was very small. The overpressure peak and energy flow density of the shock wave agreed with the explosion similarity law at all fixed water depths. The proposed calculation models have practical engineering value and generalization ability.
Study of surface tension effects on near-wall cavitation bubble collapse with a pseudopotential lattice Boltzmann model
Authors: He Jinchao , Zhou Xidong , Zhang Na , Nie Mi , Mao Weina , Lu Zhouyang
Published: March 2022

A lattice Boltzmann pseudopotential cavitation model with tunable surface tension and large density and viscosity coefficient ratios was used to simulate near-wall cavitation bubble collapse. The influences of the surface tension, bubble–wall distance, and initial pressure difference on the flow field distribution were analyzed, and the relationships between the surface tension and maximum micro-jet and collapse pressure were investigated. The results indicated that a lower surface tension intensifies the deformation of the gas–liquid interface, resulting in a more concentrated micro-jet. In addition, more surface energy is accumulated during cavitation bubble collapse for higher surface tension, strengthening the collapse intensity and increasing the maximum micro-jet velocity and collapse pressure. The time interval between the first and second pressure peaks increases with increasing wall distance. Because of the non-linear attenuation during pressure propagation, the value of the second peak decreases with increasing wall distance. Increasing the initial pressure difference leads to slower growth in the micro-jet velocity and faster growth in the collapse pressure with increasing bubble–wall distance. In addition, increasing the initial pressure difference for the same bubble–wall distance also slows the growth in the micro-jet velocity and increases the growth in the collapse pressure caused by increasing surface tension.
The hydrodynamic effects of undulating patterns on propulsion and braking performances of long-based fin
Authors: Hu Qiang-Qiang , Yu Yong-Liang
Published: March 2022

Bio-inspired long-based undulating fin propulsion is commonly employed in biological autonomous underwater vehicles (BAUVs), while the hydrodynamic characteristics of various undulating patterns are different. To investigate what kind of undulating pattern has outstanding propulsion or braking performance for BAUVs in directional maneuvers, undulations with four basic undulating patterns are numerically examined under the Open-source Field Operation And Manipulation environment at the Reynolds number of 5 × 102, 5 × 103, and 5 × 104, corresponding to viscous, transitional, and inertial flow regimes, respectively. The study is conducted at various non-dimensional phase speeds c (0.5–2.0, normalized by incoming flow speed) at a constant maximum amplitude of 0.08 and a wavelength of 0.5 (both are normalized by the fin cord length) to imitate the long-based fin. The numerical results indicate that the undulating fin motion with the amplitude envelope gradually increasing from the anterior part to the posterior (conical sinusoidal wave) part may be preferable for thrust generation; undulating with the amplitude envelope increasing from the anterior part to the mid part and decreasing toward the posterior (fusiform sinusoidal wave) presents the superior braking performance when the phase speed is low enough. Moreover, the influence of undulating patterns on the wake structure is analyzed. Through further comparative analysis for propulsion and braking performances, the results obtained here may have instructional significance to the propulsion mechanism in bionic design.
A numerical study on pulsatile non-Newtonian hemodynamics in double-fusiform abdominal aortic aneurysms
Authors: Panchal Pratik M. , Hathi Dev S. , Shah Niraj K. , Lakdawala Absar M.
Published: March 2022

Abdominal Aortic Aneurysm (AAA) is a multi-factorial pathological event that occurs in the human body. In the present work, the hemodynamics pertaining to AAA are numerically analyzed. To comprehend the blood flow phenomenon in a double-fusiform aneurysm, axisymmetric simulations of pulsatile non-Newtonian blood flow are performed using OpenFOAM. The Carreau–Yasuda model is used to evaluate the non-Newtonian behavior of blood. The Reynolds number and Womersley number are altered as per the physiologically applicable range to characterize the hemodynamics. The Dilatation Index is also varied to quantify the consequence of different enlargements of the abdominal aorta on the blood flow. Four hemodynamic indicators—time-averaged wall shear stress, Oscillatory Shear Index (OSI), Relative Residence Time (RRT), and vascular impedance—are used to identify several complications such as atherosclerosis, vascular inflammation, endothelial dysfunction, and hyperplasia. As the pulse rate increases, the chances of particle stagnation inside the aneurysm decrease due to lower RRT. Our results suggest that patients with hypoxia or bradycardia (low Womersley number) are more susceptible to atherosclerosis due to the high value of RRT. Thus, we recommend mild exercise for patients with AAA. After analyzing the hemodynamic indicators, % of area with RRT > 0.5 is identified as the critical parameter to propose a regime map. Low pulse rates are found to be critical at low flow rates, whereas high pulse rates are found to be critical with high flow rates. Furthermore, it is found that the severity increases as the size of the aneurysm increases.
Deceleration of highly charged Ni ions with compressed longitudinal kinetic energy distribution by a falling potential
Authors: Zhou Zhiqiang , Liang Shiyong , Chen Shaolong , Zhou Pengpeng , Sun Wei , Xiao Jun , Huang Yao , Guan Hua , Gao Kelin
Published: March 2022

Higher-precision optical clocks based on highly charged ions (HCIs) have become one of the means to explore new physics beyond the standard model. Usually, HCIs are produced by electron bombardment with high kinetic energy. Therefore, to realize an optical clock, the deceleration of HCIs is necessary. In this study, the design and operation of a deceleration beamline to produce low-energy HCIs are presented. We used time-of-flight technology to select pure 58Ni12+ ions. The longitudinal kinetic energy distribution of the ion beam was compressed from 11.4(4)qV (q is the electric charge of ions) to 2.2(3)qV by employing a rapidly decreasing voltage. Adopting a deceleration lens system, the longitudinal kinetic energy of the 58Ni12+ ions was reduced from 678.2(3)qV to 2.0(3)qV.
Rotating machinery anomaly detection using data reconstruction generative adversarial networks with vibration energy analysis
Authors: Li Jun , Liu Yongbao , Wang Qiang , Xing Zhikai , Zeng Fan
Published: March 2022

Rotating machines, such as engines, turbines, or gearboxes, are widely used in modern society. Their mechanical components, such as rotors, bearings, or gears, are the main parts, and any failure in them can lead to a complete shutdown of the rotating machinery. Anomaly detection in such critical systems is essential for the healthy operation of rotating machinery. As the requirement of obtaining sufficient fault data of rotating machinery is challenging to satisfy, a new anomaly detection model is proposed for rotating machinery, which can achieve anomaly detection without fault samples. The model combines vibration energy features, adversarial learning mechanism, and long short-term memory to develop a novel anomaly detection model based on data reconstruction. The model was validated using two different datasets. The proposed model achieves the highest accuracy of 98.90% for anomaly detection under different working conditions, outperforming similar models.
Study on the relationship between surface and dislocation of nanoporous copper under cyclic shear loading
Authors: Wang Yufeng , Bi Wenbo , Deng Lei , Zhang Xingming , Tang Jianfeng , Wang Liang
Published: March 2022

In this paper, molecular dynamics simulation is conducted to study the relationship between the surface and dislocation of nanoporous copper under cyclic shear loading. The results show that the dislocation and the surface have both mutual promotion and competition relationship. On one hand, the surface becomes rough owing to reconstruction caused by cyclic shear, which promotes the dislocation activities, while the dislocation activities also accelerate the process of surface reconstruction. On the other hand, there is a competition between surface reconstruction and dislocation activities: in the early cycles, the dislocation density is low, and surface reconstruction dominates stress release; in the late cycles, the surface tends to be stable, and then, the dislocation activities dominate.
Doppler evaluation of recipient cows treated with progesterone and estradiol
Authors: Guedes Pedro Henrique Evangelista , Pinna Aline Emerim , Morais Rita de Cássia Lima , de Souza Guilherme Nunes , Jacob Julio Cesar Ferraz , Carvalho Carla Fernanda Paranhos de Moura , Nogueira Luiz Altamiro Garcia , Oliveira Clara Slade
Published: March 2022

Context Due to the advances in the field of biotechnology of reproduction, success rates in embryo transfer (ET) programs have been growing continuously. Such rates are influenced by several factors, among which fertility and success in synchronising the estrus of the recipients stand out. Doppler ultrasound is emerging as a useful tool fot the assessment of fertility in recipients and for the early diagnosis of pregnancy. Aims This study aimed to verify whether luteal vascularisation, uterine haemodynamics and corpus luteum (CL) volume, evaluated only on the day of fixed-time ET (FTET), are useful parameters for the selection of Girolando recipients synchronised with progesterone and estrogen. Methods Girolando recipients received a hormonal protocol for FTET and were evaluated on the day of embryo transfer by B-mode and Doppler ultrasonography. The volume of the CL, the side of the CL, the estimation of luteal vascularisation and the Doppler indexes of the right and left uterine arteries were evaluated in real time. The ultrasound images were saved and used for later pixel counting and determination of the vascularised luteal area using specific software. Blastocysts (n = 92) produced in vitro (IVF) with Grade 1 morphology on Day 7 of development were transferred to all animals with corpus luteum. The pregnancy diagnosis was made 24 days after embryo transfer and the animals were separated into two groups, namely, pregnant and non-pregnant. Key results Retrospective analyses of luteal vascularisation; haemodynamics of uterine arteries and corpus luteum volume did not differ (P > 0.05) between the groups. The means of the Doppler indexes of the uterine arteries were not affected (P > 0.05) by the presence of CL ipsilateral to the assessed vessel. Conclusions It is concluded that the assessments of uterine haemodynamics, size and vascularisation of the CL, through Doppler ultrasonography on the day of ET, under the proposed conditions, were not useful to predict recipients with greater chances of establishing pregnancy. Implications Although Doppler is a useful tool for real-time fertility assessment, its accuracy if affected by protocols that do not guarantee synchrony between ovulation times. This suggests that other fertility assessment methods be used under these field conditions.
Cross-linkers at growing microtubule ends generate forces that drive actin transport
Authors: Alkemade Celine , Wierenga Harmen , Volkov Vladimir A. , Preciado López Magdalena , Akhmanova Anna , ten Wolde Pieter Rein , Dogterom Marileen , Koenderink Gijsje H.
Published: March 2022

Significance

Complex cellular processes such as cell migration require coordinated remodeling of both the actin and the microtubule cytoskeleton. The two networks for instance exert forces on each other via active motor proteins. Here we show that, surprisingly, coupling via passive cross-linkers can also result in force generation. We specifically study the transport of actin filaments by growing microtubule ends. We show by cell-free reconstitution experiments, computer simulations, and theoretical modeling that this transport is driven by the affinity of the cross-linker for the chemically distinct microtubule tip region. Our work predicts that growing microtubules could potentially rapidly relocate newly nucleated actin filaments to the leading edge of the cell and thus boost migration.
Recent advances in printed liquid metals for wearable healthcare sensors: a review
Authors: Liu Longhui , Huang Han , Wang Xincheng , He Pei , Yang Junliang
Published: March 2022

Wearable healthcare sensors can perform real-time health monitoring by tracking various physical signals, physiological signals, as well as electrophysiological activities of the human body. Liquid metals have become an ideal candidate material for wearable healthcare sensors due to their excellent physical and chemical properties, such as high stretchability, high electrical and thermal conductivity, as well as great biocompatibility. Printing techniques present the possibility to fabricate economically efficient, versatile, low-cost and large-area functional electronic devices based on liquid metals. A series of wearable sensors based on liquid metals through printing processes have been designed and reported. Herein, we present a review on the recent advances in printed liquid metals toward wearable healthcare sensors. A detailed landscape view on the properties of liquid metals is provided, following by the overview of printing methods, including direct writing, screen printing, inkjet printing, acoustophoretic printing and 3D printing. Sensor devices (e.g. pressure sensors, strain sensors, temperature sensors, and electrochemical sensors) employed for wearable healthcare monitoring are summarized. Finally, the key challenges and opportunities of the printed sensors based on liquid metals in personalized healthcare monitoring and human-machine interfaces are also discussed.
Safety assessments undertaken using the BIOMASS methodology: lessons learnt and methodological enhancements
Authors: Lindborg Tobias , Brown Joanne , Griffault Lise , Ikonen Ari T K , Kautsky Ulrik , Sanae Shibutani , Smith Graham , Smith Karen , Thorne Mike , Walke Russell
Published: March 2022

The International Atomic Energy Agency has coordinated an international project addressing enhancements of methods for modelling in post-closure safety assessments of solid radioactive waste disposal. The project used earlier published work from the IAEA biosphere modelling and assessment (BIOMASS) project to further develop methods and techniques. The task was supported by a parallel on-going project within the BIOPROTA forum. The output from the project is described in detail in a forthcoming IAEA report. Here an overview of the work is given to provide researchers in the broader fields of radioecology and radioactive waste disposal with a summarised review of the enhanced BIOMASS methodology and the work that has been undertaken during the project. It is hoped that such dissemination will support and promote integrated understanding and coherent treatment of the biosphere component within the overall assessment process. The key activities undertaken in the project were: review and identification of those parts of the original BIOMASS methodology that needed enhancement, discussions on lessons learned from applying the BIOMASS method, using real examples to assess the methodology and its usefulness, and writing of those parts of the methodology that were considered could benefit from refinement or for which new guidance was required to take account of scientific developments. The work has shown that the overall approach in the original BIOMASS methodology has proven sound. However, the enhanced version clarifies the need for an iterative and holistic approach with system understanding central to the approach. Specifically, experience, especially in site-specific contexts, has emphasised that adequate system understanding is essential in underpinning safety assessments for radioactive waste disposal. The integral role of the biosphere within safety assessment is also emphasised in the enhanced methodology.
Multi-layer model aided inertial navigation system for unmanned ground vehicles
Authors: Du Binhan , Shi Zhiyong , Wang Huaiguang , Han Lanyi , Song Jinlong
Published: March 2022

The inertial navigation system (INS) has been commonly adopted for unmanned ground vehicles, but it needs other systems to correct for error divergence, such as the Global Navigation Satellite System (GNSS). However, GNSS failures are inevitable, and INS must navigate independently in such situations, meaning that navigation errors will diverge fast. To solve this problem, the vehicle model aided INS is proposed. In this paper, three commonly used vehicle models are analyzed, first to discuss their disadvantages, that they contain the vehicle kinematics model (VKM), the non-holonomic constraint of VKM, and the vehicle dynamics model (VDM). Against their disadvantages, the multi-layer vehicle model aided INS is proposed. The proposed method divides the INS error parameters into the sensor layer, system layer I, and system layer II. Then, the navigation information from the INS is fused with our developed VKM and VDM at the system layer and the sensor layer respectively. Additionaly, the design of the adaptive Kalman filter is based on the VKM error model, such that the estimations can be protected from observation errors when the VKM accuracy declines. Compared to the traditional vehicle model aided INS, the proposed method can improve the accuracy and robustness of the navigation system with acceptable computational complexity.
Structural and electronic properties of double-walled G-C3N4 nanotubes: a density functional theory study
Authors: Li Lijian , Zhang Long , Zhao Chen , Zhu Yingtao , Gao Yang
Published: March 2022

In the present work, we investigated the geometric, electronic, and photocatalytic properties of g-C3N4 single-walled nanotube (SWCNNTs) and g-C3N4 double-walled nanotubes (DWCNNTs). The negative strain energy indicates that the SWCNNTs have a stable structure, while the most stable combination in the DWCNNT is (6, 0)@(12, 0). The energy band gaps of (n, 0) SWCNNTs increase while that of (n, n) SWCNNTs decrease as the diameter increase. Moreover, the calculated nanotubes have the ability of photocatalytic water splitting, and the valance band maximum of nanotubes are much lower than that of the monolayer, indicating that the nanotubes have better oxidation capacity than the monolayer. On the other hand, our calculations show that DWCNNTs have type II band alignment with a band gap width significantly smaller than that of SWCNNTs. Interestingly, DWCNNT exhibited a smaller effective mass of electrons than SWCNNTs, which is beneficial to electron migration. Therefore, the construction of nanotube is an effective way to improve the photocatalytic performance of g-C3N4 monolayer materials.
Amplified steady state bifurcations in feedforward networks
Authors: von der Gracht Sören , Nijholt Eddie , Rink Bob
Published: March 2022

We investigate bifurcations in feedforward coupled cell networks. Feedforward structure (the absence of feedback) can be defined by a partial order on the cells. We use this property to study generic one-parameter steady state bifurcations for such networks. Branching solutions and their asymptotics are described in terms of Taylor coefficients of the internal dynamics. They can be determined via an algorithm that only exploits the network structure. Similar to previous results on feedforward chains, we observe amplifications of the growth rates of steady state branches induced by the feedforward structure. However, contrary to these earlier results, as the interaction scenarios can be more complicated in general feedforward networks, different branching patterns and different amplifications can occur for different regions in the space of Taylor coefficients.
194 nm microplasma lamps driven by excitation transfer: optical sources for the 199Hg ion atomic clock and photochemistry
Authors: Park S , Mironov A E , Kim J , Park S-J , Eden J G
Published: March 2022

A series of miniature, microcavity plasma lamps emitting predominantly at 194 nm has been successfully developed and tested as the optical pump for the microwave 199Hg-ion atomic clock (40.507 GHz), replacing low pressure, RF-powered Ar/Hg discharges. Intense fluorescence on the 6p
2P1/2 → 6s
2S1/2 transition of the singly-charged 202Hg ion at 194.23 nm has been generated in arrays of cylindrical microplasmas through electron-impact excitation of He, followed by three-body formation of He2(a
3

Σ

u

+

) and Penning ionization of Hg. Emission spectroscopy and kinetic modeling of He/Hg vapor plasmas demonstrate that the population of the Hg+(62P1/2) radiating state (16.82 eV), produced by direct or two-step electron impact processes, is

<

1% of that generated by excitation transfer to Hg by H

e

2

*

. Flat, fused silica lamps having emitting areas as small as 4 mm2 and containing several mg of 202Hg and 50–800 Torr of He have been fabricated and serve as optical drivers for the Hg+ atomic clock cycle. Based on small arrays of 500 μm–1 mm diameter microcavities, these lamps produce peak and average intensities at 194 nm greater than those associated with the Hg resonance transition at ∼ 254 nm, despite the factor of

>

3 difference between the energies of the 6p
3P1 and 6p
2P1/2 states of neutral Hg and Hg+, respectively. These lamps are unique in the sense that the desired radiating species is an excited ion and the background He gas pressure can reach 1 atm, both of which contribute to a dense glow plasma placing severe demands on E/N, power conditioning, and materials selection. Nevertheless, with proper attention given to design, vacuum processing, and preparation of the lamps, lifetimes above 1500 h have been realized to date. When these lamps drive Jet Propulsion Laboratory Hg+ clocks, the stability floor has been measured to be

∼
10

−14. The implications of this lamp for gas-phase and solid-state photochemistry are also discussed.
Mode transition of the cylindrical Hall thruster with the near-anode cusp magnetic field
Authors: Gao Yuanyuan , Wang Weizong , Li Yifei , Cai Guobiao , Xue Shuwen
Published: March 2022

There are two distinct discharge modes in a 200 W cylindrical Hall thruster with the near-anode cusp magnetic field. In mode I, a divergent plume is observed at a low discharge voltage. When the discharge voltage rises over 280 V, an apparent discharge mode transition occurs along with the sharp decreasing of discharge current (by 9.9%) and electron current (by 26%) and apparent narrowing of plume angle (by 12%), bringing a convergent plume (mode II). In mode I, the most probable ion energy of ion energy distribution function declines monotonically with the increasing of plume angle. However, a non-monotonic variation characteristic of most probable ion energy is indicated in mode II, which suggests that there are two ionization regions in this mode. These novel mode transition phenomena should be attributed to the unique near-anode cusp magnetic field. In low discharge voltage conditions (mode I), as the energies of the electron population are low, they are trapped in the near-axial magnetic mirror field, and a cylindrical ionization region along thruster axis is established. When the discharge voltage rises over the threshold voltage occurring mode transition, the energies of the electron population are enhanced and the energetic electrons could escape from the mirror field and reach the upstream crossed electric and magnetic fields. As a result, an additional ionization region related to E × B drift is formed in the upstream region. The competitive relationship between the upstream ionization related to E × B drift and the near-axial ionization related with magnetic mirror field should be the leading cause of mode transition.
The distribution pattern of the electron density and the electron temperature in a weakly compressible argon plasma jet measured by a Langmuir triple probe
Authors: Cao Jinwen , Meng Xian , Han Ning , Pan Wenxia , Wu Chengkang , Huang Heji
Published: March 2022

High-speed plasma plays an important role in diverse areas. Plasma flow with a sufficiently high speed to arouse compression is usually not in thermal equilibrium, and the plasma characteristics are closely coupled with the flow field. The relation between the flow and the plasma parameters, especially the distributions of electron density, i.e. n
e, and the electron temperature, i.e. T
e, are of ultimate importance; however, this is not yet completely understood. In this work, a weakly compressible plasma jet produced by an arc torch is diagnosed using a Langmuir triple probe. The two-dimensional distributions of n
e and T
e are obtained consisting of 80 spatial points under arc currents of 70–100 A. The spatial patterns of the distributions demonstrate alternative expansion–compression wave structures. As the arc power increases, the wave structures remain almost unchanged, while n
e increases monotonically. Moreover, in some regions T
e decreases with the arc power, which has seldom been reported in the literature. In addition, the peaks of the radial distributions of T
e always deviate from the central axis. These results are compared with previous works of strongly compressible plasma flows. The phenomena are then analyzed and explained from the perspective of fluid wave-plasma interactions and the actions of the ambipolar field in the electrons.
Fine structure of streamer-to-filament transition in high-pressure nanosecond surface dielectric barrier discharge
Authors: Ding Ch , Jean A , Popov N A , Starikovskaia S M
Published: March 2022

The fine structure of a streamer-to-filament transition in a single-shot high-voltage nanosecond surface dielectric barrier discharge in molecular nitrogen at pressure P = 6 bar was studied with the help of ICCD microimaging. An intermediate discharge structure, existing for only a few nanoseconds, was observed in the time interval between two discharge modes: streamer discharge, with a typical electron density of n
e ∼ 1015 cm−3, and filamentary discharge, with n
e ∼ 1019 cm−3. The structure was observed for both polarities of the high-voltage electrode. The structure can be briefly described as a stochastic appearance of thin channels propagating a bit faster than the main ionization front of merged surface streamers, transforming in a few nanoseconds in a bi-directional ionization wave. One wave, which we associate with a feather-like structure in optical emission, propagates further away from the high-voltage electrode, and another, a backward wave of emission, propagates back towards the edge of the high-voltage electrode. When the backward wave of emission almost reaches the high-voltage electrode, the filament appears. Plasma properties of the observed structure were studied to better understand the nature of a streamer-to-filament transition. Theoretical analysis suggests that the instability of a flat front of ionization wave (Laplacian instability) triggers the streamer-to-filament transition, and that a surface stem (a tiny region with enhanced electron density) should be in the origin of the bi-directional ionization wave.
Note on the energy transport in capacitively coupled plasmas
Authors: Wu Hao , Chen Zhaoyu , Yi Lin , Jiang Wei , Zhang Ya
Published: March 2022

Particle and energy balance relations are the key to understanding the discharge in low-temperature plasmas. In this note, we derived the energy transport balances in capacitively coupled plasmas (CCPs) based on the electromagnetic theory. Then we calculated the energy transport terms in CCPs from particle-in-cell/MonteCarlo (PIC/MC) simulations, including the energy absorption, energy density, energy flow, and the energy dissipation terms, both for the particles and the field. The spatial-temporal dependant and averaged distributions of energy transport terms are shown at different pressure, demonstrating the correctness and the effectiveness of the method. This revisited method may be used to aid the studies of the electrons heating mechanism in CCP, as well as in some other plasma sources.
Electron spectra in double quantum wells of different shapes
Authors: Garbaczewski Piotr , Stephanovich Vladimir A , Engel Grzegorz
Published: March 2022

We suggest a method for calculating electronic spectra in ordered and disordered semiconductor structures (superlattices) forming double quantum wells (QWs). In our method, we represent the solution of Schrödinger equation for QW potential with the help of the solution of the corresponding diffusion equation. This is because the diffusion is the mechanism, which is primarily responsible for amorphization (disordering) of the QW structure, leading to so-called interface mixing. We show that the electron spectrum in such a structure depends on the shape of the QW, which, in turn, corresponds to an ordered or disordered structure. Namely, in a disordered substance, QW typically has smooth edges, while in ordered one it has an abrupt, rectangular shape. The present results are relevant for the heterostructures like GaAs/AlGaAs, GaN/AlGaN, HgCdTe/CdTe, ZnSe/ZnMnSe, Si/SiGe, etc, which may be used in high-end electronics, flexible electronics, spintronics, optoelectronics, and energy harvesting applications.
Proximal nitrogen reduces the fluorescence quantum yield of nitrogen-vacancy centres in diamond
Authors: Capelli Marco , Lindner Lukas , Luo Tingpeng , Jeske Jan , Abe Hiroshi , Onoda Shinobu , Ohshima Takeshi , Johnson Brett , Simpson David A , Stacey Alastair , Reineck Philipp , Gibson Brant C , Greentree Andrew D
Published: March 2022

The nitrogen-vacancy colour centre in diamond is emerging as one of the most important solid-state quantum systems. It has applications to fields including high-precision sensing, quantum computing, single photon communication, metrology, nanoscale magnetic imaging and biosensing. For all of these applications, a high quantum yield of emitted photons is desirable. However, diamond samples engineered to have high densities of nitrogen-vacancy centres show levels of brightness varying significantly within single batches, or even within the same sample. Here we show that nearby nitrogen impurities quench emission of nitrogen-vacancy centres via non-radiative transitions, resulting in a reduced fluorescence quantum yield. We monitored the emission properties of nitrogen-vacancy centre ensembles from synthetic diamond samples with different concentrations of nitrogen impurities. All samples were irradiated with high energy electrons to create high densities of nitrogen-vacancy centres relative to the concentration of nitrogen impurities. While at low nitrogen densities of 1.81 ppm we measured a lifetime of 13.9 ns, we observed a strong reduction in lifetime with increasing nitrogen density. We measure a lifetime as low as 4.4 ns at a nitrogen density of 380 ppm. The change in lifetime matches a reduction in relative fluorescence quantum yield from 77.4% to 32% with an increase in nitrogen density from 88 ppm to 380 ppm, respectively. These results will inform the conditions required to optimise the properties of diamond crystals devices based on the fluorescence of nitrogen-vacancy centres. Furthermore, this work provides insights into the origin of inhomogeneities observed in high-density nitrogen-vacancy ensembles within diamonds and nanodiamonds.
Purcell modification of Auger and interatomic Coulombic decay
Authors: Franz Janine , Buhmann Stefan Yoshi
Published: March 2022

An excited two-atom system can decay via different competing relaxation processes. If the excess energy is sufficiently high the system may not only relax via spontaneous emission but can also undergo interatomic Coulombic decay or even Auger decay. We provide analytical expressions for the rates by including them into the same quantum optical framework on the basis of macroscopic quantum electrodynamics. By comparing the rates in free space we derive the atomic properties determining which decay channel dominates the relaxation. We show that by modifying the excitation propagation of the respective process via macroscopic bodies, in the spirit of the Purcell effect, one can control the ratio between the two dominating decay rates. We can relate the magnitude of the effect to characteristic length scales of each process, analyse the impact of a simple close-by surface onto a general two-atom system in detail and discuss the effect of a cavity onto the decay rates. We finally apply our theory to the example of a doubly excited HeNe-dimer.
Cosmography with standard sirens from the Einstein Telescope
Authors: de Souza Josiel Mendonça Soares , Sturani Riccardo , Alcaniz Jailson
Published: March 2022

We discuss the power of third-generation gravitational wave
detectors to constrain cosmographic parameters
in the case of electromagnetically bright standard sirens focusing on the specific case of the Einstein Telescope.
We analyze the impact that the redshift source distribution, the number of detections
and the observational error in the luminosity distance have on the inference
of the first cosmographic parameters, and show
that with a few hundreds detections the Hubble constant
can be recovered at sub-percent level whereas the deceleration parameter at a few
percent level, both with negligible bias.