bluuebunny/crossref_metadata_2025 huggingface dataset:
Cardiologist’s exposure to radiation in cath lab measured with InstadoseTM dosimeter
Authors: Moreira Antônio Carlos , da Silva Branco Amanda Juliene , Khoury Helen Jamil , Pires Silvio Ricardo , Pereira Barbosa Adriano Henrique , Bitelli Medeiros Regina
Published: February 2023

Introduction: complex fluoroscopy-guided interventional procedures in cardiology are known to result in higher radiation doses for patients and staff. Purpose: to estimate the equivalent dose received in different regions of the cardiologist’s body in catheterism (CATH) and percutaneous coronary intervention (PCI) procedures, as well as to evaluate the effectiveness of monitoring the doses in the catheritization laboratory (cath lab) using a direct ion storage dosimeter. Materials and methods: the InstadoseTM and the thermoluminescent dosimeters (TLD-100) were fixed simultaneously in the following regions of the cardiologist’s body: near the eyes (left and right), the trunk region (over the lead apron) and the left ankle. Occupational doses were recorded during 86 procedures (60% CATH). Results: catheterization procedures showed third quartile dose values near to the left eye region equal to 0.10 mSv (TLD-100) and 0.12 (InstadoseTM) and for intervention 0.15 mSv (TLD-100 and InstadoseTM). The doses measured in the trunk region, over the lead apron, were about 13% higher for catheterization procedures and 20% higher for intervention procedures compared to left eye region measurements. The Wilcoxon–Mann–Whitney test was applied for unpaired data for all body regions, comparing the data obtained between the TLD-100 and InstadoseTM dosimeters. For CATH and PCI, the responses of the TLD-100 and InstadoseTM dosimeters are considered equal for all analysed regions (p > 0.05) with the exception of the right eye region. Conclusion: the InstadoseTM passive dosimeter can be useful as a complementary assessment in the monitoring of a cardiologist’s personal occupational doses in the cath lab.
JRODOS customization for Pakistan and assessment of the consequences of a hypothetical nuclear accident
Authors: Hussain Mazzammal , Mehboob Khurram , Ilyas Syed Zafar , Smith Kilian , Shaheen Saima
Published: February 2023

Since the Chernobyl disaster in 1986, decision support systems and modelling tools are utilized in response to nuclear and radiological emergencies. The Java-based Real-time On-line Decision Support System (JRODOS) is a decision support tool that can be utilised in response to an emergency in managing off-site radiological consequences. This article documents the customization and use of JRODOS for Pakistan. The JRODOS was tailored to the local Pakistan conditions, and a case study for a theoretical nuclear power plant accident was used to assess JRODOS's feasibility as a decision support tool. A worse case probabilistic accident scenario was used to identify zones and areas where urgent protective actions, early protective actions and food restriction and other response actions could be required. The areas and distances identified for the implementation of protective and response actions for such a hypothetical accident were found to be in agreement with the International Atomic Energy Agency (IAEA) suggested emergency planning zones and distances. Additionally, the implications of meteorological and source term input parameters on predicting the radiation doses to members of the public were investigated. It was identified that the output of such tools strongly depends on the availability and accuracy of the input parameters such as radioactive release and meteorological data. Limitations and uncertainties associated with these tools need to be considered in deciding on protective and other response actions in response to a nuclear accident. As established by the IAEA, protective and other response actions need to be applied on a graded approach taking into account the protection strategy and uncertainties and limitation in the available information and criteria, based on the conditions at the facility and off the site.
Gearbox fault diagnosis based on generalized multivariate logarithmic regularization
Authors: Yin Na , Sun Dengyun , Meng Zong , Li Jimeng , Cao Lixiao , Fan Fengjie
Published: February 2023

Feature extraction based on sparse representation is widely applied in the field of mechanical fault diagnosis. L1 norm regularization is a classical sparse regularization method, but this method has sparse underestimation for large-value features. A signal sparse representation method based on generalized multivariate logarithmic regularization is proposed in this paper. First, the sparse penalty term in the proposed method is designed according to the minimum convolution and logarithmic function, namely the generalized logarithmic non-convex penalty function. Then, the convexity condition of the objective function is studied to verify the feasibility of the method. The applicability of the method is also improved by analyzing the parameter constraint relation in the objective function. Finally, the sparse optimal solution is obtained by the forward-back splitting algorithm. Experiments show that compared with other non-convex sparse models, the proposed method can solve the problem of sparse underestimation more effectively and improve the reliability of gearbox fault diagnosis.
A critical review of fabrication challenges and reliability issues in top/bottom gated MoS2field-effect transistors
Authors: Thoutam Laxman Raju , Mathew Ribu , Ajayan J , Tayal Shubham , Nair Shantikumar V
Published: February 2023

The voyage of semiconductor industry to decrease the size of transistors to achieve superior device performance seems to near its physical dimensional limitations. The quest is on to explore emerging material systems that offer dimensional scaling to match the silicon- based technologies. The discovery of atomic flat two-dimensional materials has opened up a completely new avenue to fabricate transistors at sub-10 nanometer level which has the potential to compete with modern silicon-based semiconductor devices. Molybdenum disulfide (MoS2) is a two-dimensional layered material with novel semiconducting properties at atomic level seems like a promising candidate that can possibly meet the expectation of Moore’s law. This review discusses the various ‘fabrication challenges’ in making MoS2based electronic devices from start to finish. The review outlines the intricate challenges of substrate selection and various synthesis methods of mono layer and few-layer MoS2. The review focuses on the various techniques and methods to minimize interface defect density at substrate/MoS2interface for optimum MoS2-based device performance. The tunable band-gap of MoS2with varying thickness presents a unique opportunity for contact engineering to mitigate the contact resistance issue using different elemental metals. In this work, we present a comprehensive overview of different types of contact materials with myriad geometries that show a profound impact on device performance. The choice of different insulating/dielectric gate oxides on MoS2in co-planar and vertical geometry is critically reviewed and the physical feasibility of the same is discussed. The experimental constraints of different encapsulation techniques on MoS2and its effect on structural and electronic properties are extensively discussed.
A single-step plasma method for rapid production of 2D, ferromagnetic, surface vacancy-engineered MoO3−x
nanomaterials, for photothermal ablation of cancer
Authors: Rahman Mizanur , Pemmaraju Deepak B , Murty Upadhyayula Suryanarayana , Phukan Sarat , Deshpande Uday P , Sathe Vasant , Kakati Mayur
Published: February 2023

A rapid, clean plasma-chemical technique is demonstrated here, for cost-effective, synthesis of surface vacancy engineered, 2D, molybdenum-oxide nanomaterials, during a one-step, integrated synthesis-hydrogenation process for biomedical applications. A laminar plasma beam populated with O and H radicals impinges on a molybdenum target, out of which molybdenum-oxide nanomaterials are very rapidly generated with controlled surface O vacancies. 2D, dark-blue coloured, nano-flake/ribbon like MoO3−x
is produced maximum up to 194 g h−1, the core of which still remains as stoichiometric molybdenum-oxide. These nanomaterials can get heated-up by absorbing energy from a near-infrared (NIR) laser, which enable them as photothermal therapy (PTT) candidate material for the invasive precision therapy of cancer. The surface defects endows the products with robust ferromagnetism at room temperature conditions (maximum saturation-magnetization: 6.58 emu g−1), which is order of magnitude stronger than most other vacancy engineered nanomaterials. These nanometric metal-oxides are observed to be perfectly compatible in animal physiological environment and easily dispersed in an aqueous solution even without any pre-treatment. The MoO3−x
nanomaterials are stable against further oxidation even under prolonged atmospheric exposure. In vitro experiments confirm that they have ideal efficacy for photothermal ablation of human and murine melanoma cancer at relatively lower dose. During in vivo PTT treatments, they may be manipulated with a simple external magnetic field for targeted delivery at the malignant tumours. It is demonstrated that commensurate to the neutralization of the malignant cells, the nanomaterials themselves get self-degraded, which should get easily excreted out of the body.
Haralick texture feature analysis for characterization of specific energy and absorbed dose distributions across cellular to patient length scales
Authors: Mansour Iymad R , Thomson Rowan M
Published: February 2023

Objective. To investigate an approach for quantitative characterization of the spatial distribution of dosimetric data by introducing Haralick texture feature analysis in this context. Approach. Monte Carlo simulations are used to generate 3D arrays of dosimetric data for 2 scenarios: (1) cell-scale microdosimetry: specific energy (energy imparted per unit mass) in cell-scale targets irradiated by photon spectra (125I, 192Ir, 6 MV); (2) tumour-scale dosimetry: absorbed dose in voxels for idealized models of 125I permanent implant prostate brachytherapy, considering ‘TG186’ (realistic tissues including 0% to 5% intraprostatic calcifications; interseed attenuation) and ‘TG43’ (water model, no interseed attenuation) conditions. Five prominent Haralick features (homogeneity, contrast, correlation, local homogeneity, entropy) are computed and trends are interpreted using fundamental radiation physics. Main results. In the cell-scale scenario, the Haralick measures quantify differences in 3D specific energy distributions due to source spectra. For example, contrast and entropy are highest for 125I reflecting the large variations in specific energy in adjacent voxels (photoelectric interactions; relatively short range of electrons), while 6 MV has the highest homogeneity with smaller variations in specific energy between voxels (Compton scattering dominates; longer range of electrons). For the tumour-scale scenario, the Haralick measures quantify differences due to TG186/TG43 simulation conditions and the presence of calcifications. For example, as calcifications increase from 0% to 5%, contrast increases while correlation decreases, reflecting the large differences in absorbed dose in adjacent voxels (higher absorbed dose in voxels with calcification due to photoelectric interactions). Significance. Haralick texture analysis provides a quantitative method for the characterization of 3D dosimetric distributions across cellular to tumour length scales, with promising future applications including analyses of multiscale tissue models, patient-specific data, and comparison of treatment approaches.
A Geant4 shielding design for the first US carbon multi-ion hybrid synchrotron facility
Authors: Dougherty Jingjing M , Bolst David , Furutani Keith M , Guatelli Susanna , Liang Xiaoying , Rosenfeld Anatoly , Beltran Chris J
Published: February 2023

The Mayo Clinic Florida Integrated Oncology Building will be the home of the first spot-scanning only carbon/proton hybrid therapy system by Hitachi, Ltd. It will provide proton beams up to kinetic energies of 230 MeV and carbon beams up to 430 MeV n−1 for clinical deployment. To provide adequate radiation protection, the Geant4 (v10.6) Monte Carlo toolkit was utilized to quantify the ambient dose equivalent at a 10 mm depth (H*(10)) for photons and neutrons. To perform accurate calculations of the ambient dose equivalent, three-dimensional computer-aided design files of the entire planned facility were imported into Geant4, as well as certain particle system components such as the bending magnets, fast Faraday cup, and gantry. Particle fluence was scored using 60 cm diameter spheres, which were strategically placed throughout areas of interests. Analytical calculations were performed as first-pass design checks. Major shielding slabs were optimized using Geant4 simulations iteratively, with more than 20 alternative designs evaluated within Geant4. The 430 MeV n−1 carbon beams played the most significant role in concrete thickness Requirements. The primary wall thickness for the carbon fixed beam room is 4 meters. The presence of the proton gantry structure in the simulation caused the ambient dose equivalent to increase by around 67% at the maze entrance, but a decrease in the high energy beam transport corridor. All shielding primary and secondary goals for clinical operations were met per state regulation and national guidelines.
Investigating the potential contribution of inter-track interactions within ultra-high dose-rate proton therapy
Authors: Thompson Shannon J , Prise Kevin M , McMahon Stephen J
Published: February 2023

Objective. Laser-accelerated protons offer an alternative delivery mechanism for proton therapy. This technique delivers dose-rates of ≥109 Gy s−1, many orders of magnitude greater than used clinically. Such ultra-high dose-rates reduce delivery time to nanoseconds, equivalent to the lifetime of reactive chemical species within a biological medium. This leads to the possibility of inter-track interactions between successive protons within a pulse, potentially altering the yields of damaging radicals if they are in sufficient spatial proximity. This work investigates the temporal evolution of chemical species for a range of proton energies and doses to quantify the circumstances required for inter-track interactions, and determine any relevance within ultra-high dose-rate proton therapy. Approach. The TOPAS-nBio Monte Carlo toolkit was used to investigate possible inter-track interactions. Firstly, protons between 0.5 and 100 MeV were simulated to record the radial track dimensions throughout the chemical stage from 1 ps to 1 μs. Using the track areas, the geometric probability of track overlap was calculated for various exposures and timescales. A sample of irradiations were then simulated in detail to compare any change in chemical yields for independently and instantaneously delivered tracks, and validate the analytic model. Main results. Track overlap for a clinical 2 Gy dose was negligible for biologically relevant timepoints for all energies. Overlap probability increased with time after irradiation, proton energy and dose, with a minimum 23 Gy dose required before significant track overlap occurred. Simulating chemical interactions confirmed these results with no change in radical yields seen up to 8 Gy for independently and instantaneously delivered tracks. Significance. These observations suggest that the spatial separation between incident protons is too large for physico-chemical inter-track interactions, regardless of the delivery time, indicating such interactions would not play a role in any potential changes in biological response between laser-accelerated and conventional proton therapy.
Adaptive tetrahedral interpolation for reconstruction of uneven freehand 3D ultrasound
Authors: Wang Yifan , Fu Tianyu , Wu Chan , Fan Jingfan , Song Hong , Xiao Deqiang , Lin Yucong , Liu Fangyi , Yang Jian
Published: February 2023

Objective. Freehand 3D ultrasound volume reconstruction has received considerable attention in medical research because it can freely perform spatial imaging at a low cost. However, the uneven distribution of the original ultrasound images in space reduces the reconstruction effect of the traditional method. Approach. An adaptive tetrahedral interpolation algorithm is proposed to reconstruct 3D ultrasound volume data. The algorithm adaptively divides the unevenly distributed images into numerous tetrahedrons and interpolates the voxel value in each tetrahedron to reconstruct 3D ultrasound volume data. Main results. Extensive experiments on simulated and clinical data confirm that the proposed method can achieve more accurate reconstruction than six benchmark methods. Specifically, the averaged interpolation error at the gray level can be reduced by 0.22–0.82, and the peak signal-to-noise ratio and the mean structure similarity can be improved by 0.32–1.83 dB and 0.01–0.05, respectively. Significance. With the parallel implementation of the algorithm, one 3D ultrasound volume data with size 279 × 279 × 276 can be reconstructed from 100 slices 2D ultrasound images with size 200 × 200 at 1.04 s. Such a quick and accurate approach has practical value in medical research.
Deep learning based automatic contour refinement for inaccurate auto-segmentation in MR-guided adaptive radiotherapy
Authors: Ding Jie , Zhang Ying , Amjad Asma , Sarosiek Christina , Dang Nguyen Phuong , Zarenia Mohammad , Li X Allen
Published: February 2023

Objective. Fast and accurate auto-segmentation is essential for magnetic resonance-guided adaptive radiation therapy (MRgART). Deep learning auto-segmentation (DLAS) is not always clinically acceptable, particularly for complex abdominal organs. We previously reported an automatic contour refinement (ACR) solution of using an active contour model (ACM) to partially correct the DLAS contours. This study aims to develop a DL-based ACR model to work in conjunction with ACM-ACR to further improve the contour accuracy. Approach. The DL-ACR model was trained and tested using bowel contours created by an in-house DLAS system from 160 MR sets (76 from MR-simulation and 84 from MR-Linac). The contours were classified into acceptable, minor-error and major-error groups using two approaches of contour quality classification (CQC), based on the AAPM TG-132 recommendation and an in-house classification model, respectively. For the major-error group, DL-ACR was applied subsequently after ACM-ACR to further refine the contours. For the minor-error group, contours were directly corrected by DL-ACR without applying an initial ACM-ACR. The ACR workflow was performed separately for the two CQC methods and was evaluated using contours from 25 image sets as independent testing data. Main results. The best ACR performance was observed in the MR-simulation testing set using CQC by TG-132: (1) for the major-error group, 44% (177/401) were improved to minor-error group and 5% (22/401) became acceptable by applying ACM-ACR; among these 177 contours that shifted from major-error to minor-error with ACM-ACR, DL-ACR further refined 49% (87/177) to acceptable; and overall, 36% (145/401) were improved to minor-error contours, and 30% (119/401) became acceptable after sequentially applying ACM-ACR and DL-ACR; (2) for the minor-error group, 43% (320/750) were improved to acceptable contours using DL-ACR. Significance. The obtained ACR workflow substantially improves the accuracy of DLAS bowel contours, minimizing the manual editing time and accelerating the segmentation process of MRgART.
Activation of vibrational-induced CO2 dissociation in cold non-equilibrium plasma
Authors: Pietanza Lucia Daniela , Colonna Gianpiero , Capitelli Mario
Published: February 2023

The activation of vibrational-induced dissociation of CO2 in cold non-equilibrium plasma discharges is investigated by means of a 0D self-consistent kinetic model, which, with a state-to-state approach, is able to calculate the CO2 vibrational distribution function (vdf) of the asymmetric mode levels, the electron energy distribution function and the corresponding vibrational-induced and electron impact CO2 dissociation rates. The conditions for the onset of such activation are linked to the achievement of a sufficiently high CO2 vibrational excitation characterized by the presence of a non-equilibrium plateau in the CO2 vdf, resulting from the combined effect of electron–vibrational and vibrational–vibrational collisions, which, by overpopulating the higher vibrational levels, enhances dissociation. Such non-equilibrium conditions are maximized at lower gas temperature, lower pressure and higher power density values. In particular, for the power density, an activation threshold value can be obtained from simulations and its dependence on the gas temperature and pressure can be investigated. The dependence of the maximum vibrational temperature reached at the end of the discharge as a function of the gas temperature and pressure is also analyzed. A satisfactory agreement from our simulation results with the Kotov’s criterion for vibrational activation has been found.
Dense plasma focus: different cathode geometries and their influence on the hard x-ray production
Authors: Barbaglia M , Giovachini R , Milanese M
Published: February 2023

Using the plasma-focus device called PACO (Plasma Auto COnfinado), three types of cathodes were experimentally investigated to evaluate their influence on the hard x-ray production. Two barred cathodes with diameters of 82 mm and 90 mm and one cathode without any specific structure (i.e. the current sheet flowed freely on the radial axis) were tested for this work. In every experiment, the capacitor bank was charged to 31 kV. The gas used was deuterium in the pressure range of 0.5 mbar and 3.0 mbar. The production of neutrons and hard x-ray simultaneously was not detected outside this range. Using the cathode with a diameter of 82 mm the hard x-ray production was maximized.
Modeling and analysis of frequency-variable 2–2 cement-based piezoelectric transducers
Authors: Lan Chengming , Wen Lijie , Wang Jianjun , Li Weijie , Tang Lihua
Published: February 2023

The 2–2 cement-based piezoelectric transducers can be used as high-performance actuators and sensors. However, the existing designs with fixed electromechanical properties cannot meet some special application requirements, such as the tuning working frequency to achieve high precision monitoring purpose. To address this issue, a type of frequency-variable 2–2 cement-based piezoelectric transducers is proposed in this paper. Theoretical models of the proposed transducer are established, and the analytical solutions of its longitudinal vibration are obtained. The theoretical models are verified by comparing their results with those of the existing literature for some special examples, and with the finite element results for a special case. In addition, the effects of the tuning resistance, the ratio of piezoelectric layer numbers between the active and passive elements, the electrical connections of piezoelectric layers, and the total number of piezoelectric layers on the electromechanical properties of transducer are discussed. It is demonstrated that the proposed frequency-variable 2–2 cement-based piezoelectric transducers can obtain a large tunable bandwidth by adjusting the appropriate ratio of piezoelectric layer numbers between the active and passive elements and their electrical connections, which provides a theoretical basis for designing and optimizing this type of transducers.
A prediction method for the screening current induced field in HTS magnets based on time series models
Authors: Wang Mingyang , Meng Xuan’ang , Cai Tiantian , Sheng Jie , Li Zhuyong , Hong Zhiyong , Jin Zhijian
Published: February 2023

Due to their special electromagnetic properties, high temperature superconducting (HTS) conductors have become a potential solution for ultra-high field magnet and energy storage applications. However, the screening current induced field (SCIF) has been demonstrated to be the main limitation of high field HTS magnets in actual applications. Based on time series models, this paper presents a prediction method of SCIF to support the design and application of HTS magnets. First, we analyze the data characteristics of the SCIF hysteresis loop. The simulated dataset is prepared for two typical magnet structures: single pancake and solenoid. Then, time series models are proposed for the SCIF prediction. Through intuitive analysis and evaluation metrics, the training performance of time series models is confirmed. After a discussion of hyper-parameters and dimension reduction, the optimized prediction performance is obtained for the SCIF hysteresis loop. In conjunction with the iterative prediction mode, we finally achieve a feasible and effective prediction method of SCIF for HTS magnets. This will provide a tool and research strategy to support the general finite element method.
FPGA implementation, controls and synchronization of autonomous Josephson junction jerk oscillator
Authors: Dongmo Eric Donald , Ramadoss Janarthanan , Tchamda André Rodrigue , Sone Michael Ekonde , Rajagopal Karthikeyan
Published: February 2023

This paper reports the field programmable gate array (FPGA) implementation of an autonomous Josephson junction jerk oscillator (AJJJO) and the investigated coexisting and chaotic attractors besteered, with different synchronization achieved. AJJJO displays bistability, megastability, and coexistence between limit cycle and self-excited chaotic attractors, which is validated by the FPGA implementation. The elimination of chaotic dynamics exhibited by AJJJO was done by using a double single controller via numerical simulations. The coexisting attractors between limit cycle and self-excited chaotic attractors are destroyed and besteered to the wanted path via the linear augmentation control method. Moreover, controllers are employed to achieve the difference synchronization of three identical coupled chaotic AJJJOs resulting from various starting conditions. Finally, numerical simulations of three identical coupled chaotic AJJJOs indicate the effectiveness of the difference synchronization.
Verification and development of a metamaterial with large bandwidth smooth transmission properties for the thermal properties sensing of Xuan paper
Authors: Wu Dan , Wu Yu , Huang Ge , Zhong Min
Published: February 2023

Metamaterial sensors are widely used because of their rich resonance behaviors. However, due to the dependence on resonance properties, many metamaterial sensors are difficult to be applied in measurement of the stationary thermal properties of Xuan paper samples in a wide frequency range. Many important properties of Xuan paper samples are related to thermal resonance properties,. such as folding resistance, tensile strength, ink-run property, whiteness, dry heat and wet heat aging. Here, a metamaterial sensor with smooth transmission performance in the operating frequency band is designed and fabricated. In experiments, by increasing temperature, the time for the thermal response current of the Xuan paper samples to reach the peak value is significantly reduced, and the average peak value is increased. The heat conduction of the Xuan paper samples is increased and the thermal resistance is reduaced. When the thickness of the Xuan paper sample is gradually increased, the time required for the thermal response current to reach the peak value is gradually increased and the average peak value is decreased. When the concentration of alum gelatin solution applied on the surface of the Xuan paper sample is gradually increased, the corresponding thermal response current is enhanced, and the time required to reach the peak is significantly reduced. The results show that the metamaterial sensor can be used to measure the thermal properties of Xuan paper samples.
Magnetic oscillation spectrum of surface resistance in layered organic compounds
Authors: Krstovska D , Skeparovski A
Published: February 2023

The magnetic quantum oscillations of surface resistance in quasi-two dimensional layered organic conductors have been obtained numerically for a magnetic field parallel to the surface. The resonance fields, which were theoretically calculated in a previous work on surface states, are found to coincide closely to the positions of the maxima in the ∂R/∂B curves. We find that, in quasi-two dimensional organic conductors, the transitions between the adjacent surface states are the most present transitions in the sum curve for surface resistance derivative oscillation spectrum. Our results, obtained from the calculations of the oscillation spectra of the individual series and the sum of six series, confirm that the theoretical description of surface states in the anisotropic organic conductors is essentially correct in its numerical aspects. These studies will be very helpful for analyzing and explaining the experimental curves and for their comparison with the theoretical results. Since there are yet no experimental data on surface impedance oscillations in quasi-two dimensional organic conductors with this work we would like to shed new light on this problem in order to motive new research in that direction mostly because of a need of such studies for a possible utilization of surface effects in the existing organic devices.
Distribution of 222Rn decay products in a soil sample
Authors: Alexandrescu B , Sima O , Ujeniuc S , Pojar I , Suvaila R
Published: February 2023

Common practice analysis of environmental samples is usually performed by assuming radon and its decay products from the U-Ra natural radioactive series are uniformly spread within the entire sample volume. This uniform distribution is an assumption we intended to test using a volume sample. The results show that the actual distribution is not uniform and consequently needs to be treated as such for both measurement purposes and related simulations. Immediate applications include cross-disciplinary activities such as environmental studies, metrology applications and health (radiation hazard).
Spiral light beams inspired by galaxies with dark matter
Authors: Mendoza-Hernández Job
Published: February 2023

The rotation curves of galaxies reveal the presence of dark matter, which is currently one of the biggest mysteries in physics. We use the orbital angular momentum and linear momentum to connect two systems: the galaxies and the light beams. We customize the phase in light beams as a mixture of the radial and azimuthal components acting on a seed beam to show that their local linear momentum mimics the rotation curves behavior of galaxies. We theoretically analyze the resultant beams, which have a spiral behavior with one or more arms as they propagate, and an increase of topological charges in the central region.The analogy with astronomical phenomena can offer a renewed approach to tailoring the light beams and their fundamental properties.
Dark matter prospects with COSI: ALPs, PBHs and sub-GeV dark matter
Authors: Caputo Andrea , Negro Michela , Regis Marco , Taoso Marco
Published: February 2023

We study the prospects in the search of dark matter offered by the newly selected NASA MeV mission COSI (Compton Spectrometer and Imager). This instrument is designed and optimized to detect spectral lines, and we show it offers an exquisite possibility to detect dark matter directly decaying or annihilating into monochromatic gamma-rays. This is the case, for example, for axion-like particles (ALPs) which undergo decay into two photons. Furthermore, we show that COSI can lead to important progress in the quest for primordial black holes (PBHs) dark matter, through measurements of the 511 keV line from the positrons produced via Hawking evaporation.
We also outline opportunities for the search of continuum signals, such as those expected from sub-GeV dark matter annihilation/decay into leptons and PBH evaporation into photons. We find that also in this case COSI can lead to improvements of current bounds.
Flux-controllable and fast state inversion in a Laudau–Zener system of superconducting charge qubit
Authors: Yan Run-Ying , Feng Zhi-Bo
Published: February 2023

Coherent control of quantum systems in an optimized manner is of significance to information processing and state engineering. In this paper, an effective scheme is proposed for implementing rapid state inversion in a Laudau–Zener (LZ) system of superconducting charge qubit. By linearly adjusting time-dependent gate charge, the system with a given tunneling splitting of energy can be described by the LZ model. By means of the applied flux capable of inducing desired level spacing, qubit state inversion with high probability can be performed in a short time. We further address the criterion to ensure system evolution with negligible non-adiabatic excitation. With the accessible decoherence rates, high-fidelity operations can be obtained numerically. Without adding auxiliary driving, the present strategy could perform the shortcut-like accelerated operation, which paves a promising avenue towards optimized information processing with superconducting qubits.
Physical Parameters of W UMa Type Contact Binaries and Their Stability of Mass Transfer
Authors: Gebreyesus Berikol Tekeste , Negu Seblu Humne
Published: February 2023

In this study, we determined the physical parameters of W UMa type contact binaries and their stability of mass transfer with different stellar mass ranges over a broad space by applying the basic dynamical evolution equations of the W UMa type contact binaries using accretor and donor masses between 0.079 and 2.79 M
⊙. In these systems, we have studied the three subclasses of W UMa systems of A-, B- and W-type contact binaries using the initial and final mass ranges and we investigated different stellar and orbital parameters for the subclasses of W UMa systems. We examined the stability of the W UMa type contact binaries using the orbital parameters such as critical mass ratio, Roche lobe radius of the donor star and mass ratio of these systems. Thus, we computed the observed and calculated physical parameters of A-, B- and W-type W UMa systems. Moreover, we determined the combined and color temperatures to classify the three subclasses of the systems. Also, we presented the result of the internal stellar structure and evolution of W UMa type contact binaries by using the polytropic model.
Probing the Variation of Reverberation Lags along with X-Ray Flux in the AGN Mrk 704
Authors: Sriram K. , Lahiri Deblina , Agrawal Vivek K. , Nour D. , Choi C. S.
Published: February 2023

Understanding the variation of lags with respect to the X-ray flux is important to explore the geometry of the inner region of the accretion disk in AGNs. We performed frequency-lag, energy–lag and spectral studies for two sets of observations, in order to investigate the variations in lags with respect to X-ray flux in the AGN source Mrk 704 using the XMM-Newton observatory. We divided one of the light curves into two sections which were noticed to exhibit a flux variation. The frequency-lag spectra in different energy domains revealed that reverberation (soft) lags varied along with the flux. For the first time, we show that the blurred reflection model can consistently explain the soft excess observed in the X-ray spectra for this source. The fluxes of soft (i.e., reflection) and hard components were noted to vary by ∼18% and ∼9% respectively, across the sections. The soft lag amplitude was found to be larger at the high flux state than the amplitude at the low flux state. Most importantly, we found that both frequency-lag and energy–lag spectra do not display significant variation between two observational data sets despite a flux variation of 43%. This phenomenon cannot be explained by the reflection model because the soft lag amplitudes must be larger in the high flux state. The probable scenario is that, in the low flux state, the obscuring cloud delays the reflected soft photons which increases the soft lag amplitude.
Total ionizing dose effects on ring-oscillators and SRAMs in a commercial 28 nm CMOS technology
Authors: Borghello G. , Bergamin G. , Ceresa D. , Pejašinović R. , Diaz F.P. , Kloukinas K. , Pulli A. , Ripamonti G. , Caratelli A. , Andorno M.
Published: February 2023

A test chip with 368 ring-oscillators and 4 different SRAMs has been designed to study the effect of total ionizing dose on a commercial 28 nm CMOS technology. The chip has been exposed to 1 Grad(SiO2), followed by a week of annealing at T = 100 °C. The results will be compared to those obtained on single (i.e., isolated) devices in the same 28 nm process and on a similar chip in 65 nm CMOS technology. This test confirms the robustness of the 28 nm technology to ionizing radiation, enabling the development of ASICs capable of surviving in environments with hundreds of Mrad.
Check on the features of potted 20-inch PMTs with 1F3 electronics prototype at Pan-Asia
Authors: Liu Caimei , Li Min , Wang Zhimin , Hu Jun , Anfimov Nikolay , Fan Lei , Garfagnini Alberto , Gong Guanghua , Hou Shaojing , Ji Xiaolu , Jiang Xiaoshan , Korablev Denis , Lachenmaier Tobias , Ma Si , Ma Xiaoyan , Ning Zhe , Olshevskiy Alexander G. , Peng Zhaoyuan , Qin Zhonghua , Sterr Tobias , Sun Yunhua , Tietzsch Alexander Felix , Wang Jun , Wang Wei , Wang Yangfu , Wen Kaile , Wonsak Bjoern Soenke , Xie Wan , Xu Meihang , Yan Xiongbo , Yang Yifan , Zhao Rong , Zhou Tong , Zhu Kejun
Published: February 2023

The Jiangmen underground neutrino observatory (JUNO) is a
neutrino project with a 20-kton liquid scintillator detector located
700-m underground. The large 20-inch PMTs are one of the crucial
components of the JUNO experiment aiming for precision neutrino
measurements with better than 3% energy resolution at 1 MeV. The
excellent energy resolution and a large fiducial volume provide many
exciting opportunities for addressing important topics in neutrino
and astroparticle physics. With the container #D at JUNO Pan-Asia
PMT testing and potting station, the features of waterproof potted
20-inch PMTs were measured with JUNO 1F3 electronics prototype in
waveform and charge, which are valuable for a better understanding
of the performance of the waterproof potted PMTs and the JUNO 1F3
electronics. In this paper, the basic features of the JUNO 1F3
electronics prototype run at Pan-Asia will be introduced, followed
by an analysis of the waterproof potted 20-inch PMTs and a
comparison with the results from commercial electronics used by
container #A and #B.
Development and characterization of a passive, bio-inspired flow-tracking sensor
Authors: Galler J N , Rival D E
Published: February 2023

The effective natural transport of seeds in turbulent atmospheric flows is found across a myriad of shapes and sizes. However, to develop a sensitive passive sensor required for large-scale (in situ) flow tracking measurements, systems suffer from inertial lag due to the increased size and mass needed for optical visibility, or by carrying a sensor payload, such as an inertial measurement unit (IMU). While IMU-based flow sensing is promising for beyond visual line-of-sight applications, the size and mass of the sensor platform results in reduced flow fidelity and, hence, measurement error. Thus, to extract otherwise inaccessible flow information, a flow-physics-based tracer correction is developed through the application of a low-order unsteady aerodynamic model, inspired by the added-mass concept. The technique is evaluated using a sensor equipped with an IMU and magnetometer. A spherical sensor platform, selected for its symmetric geometry, was subject to two canonical test cases including an axial gust as well as the vortex shedding generated behind a cylinder. Using the measured sensor velocity and acceleration as inputs, an energized-mass-based dynamic model is used to back-calculate the instantaneous flow velocity from the sensor measurements. The sensor is also tracked optically via a high-speed camera while collecting the inertial data onboard. For the 1D test case (axial gust), the true (local) wind speed was estimated from the energized-mass-based model and validated against particle image velocimetry measurements, exhibiting good agreement with a maximum error of 10%. For the cylinder wake (second test case), the model-based correction enabled the extraction of the velocity oscillation amplitude and vortex-shedding frequency, which would have otherwise been inaccessible. The results of this study suggest that inertial (i.e. large and heavy) IMU-based flow sensors are viable for the extraction of Lagrangian tracking at large atmospheric scales and within highly-transient (turbulent) environments when coupled with a robust dynamic model for inertial correction.
Porous polymeric microparticles foamed with supercritical CO2 as scattering white pigments
Authors: Borgmann Luisa Maren , Johnsen Siegbert , Santos de Oliveira Cristine , Martins de Souza e Silva Juliana , Li Juan , Kirchlechner Christoph , Gomard Guillaume , Wiegand Gabriele , Hölscher Hendrik
Published: February 2023

Nowadays, titanium dioxide (TiO2) is the most commercially relevant white pigment. Nonetheless, it is widely criticized due to its energy-intensive extraction and costly disposal of harmful by-products. Furthermore, recent studies discuss its potential harm for the environment and the human health. Environment-friendly strategies for the replacement of TiO2 as a white pigment can be inspired from nature. Here whiteness often originates from broadband light scattering air cavities embedded in materials with refractive indices much lower than that of TiO2. Such natural prototypes can be mimicked by introducing air-filled nano-scale cavities into commonly used polymers. Here, we demonstrate the foaming of initially transparent poly(methyl methacrylate) (PMMA) microspheres with non-toxic, inert, supercritical CO2. The properties of the foamed, white polymeric pigments with light scattering nano-pores are evaluated as possible replacement for TiO2 pigments. For that, the inner foam structure of the particles was imaged by phase-contrast x-ray nano-computed tomography (nano-CT), the optical properties were evaluated via spectroscopic measurements, and the mechanical stability was examined by micro compression experiments. Adding a diffusion barrier surrounding the PMMA particles during foaming allows to extend the foaming process towards smaller particles. Finally, we present a basic white paint prototype as exemplary application.
4DEnVar-based inversion system for ammonia emission estimation in China through assimilating IASI ammonia retrievals
Authors: Jin Jianbing , Fang Li , Li Baojie , Liao Hong , Wang Ye , Han Wei , Li Ke , Pang Mijie , Wu Xingyi , Xiang Lin Hai
Published: February 2023

Atmospheric ammonia has been hazardous to the environment and human health for decades. Current inventories are usually constructed in a bottom-up manner and subject to uncertainties and incapable of reproducing the spatiotemporal characteristics of ammonia emission. Satellite measurements, for example, Infrared Atmospheric Sounder Interferometer (IASI) and Cross-Track Infrared Sounder, which provide global coverage of ammonia distribution, have gained popularity in ammonia emission estimation through data assimilation methods. However, satellite-based emission inversion studies on China are limited. In this study, we propose a four-dimensional ensemble variational-based ammonia emission inversion system to optimize ammonia emissions in China. It was developed by assimilating the IASI ammonia retrievals onboard Meteorological Operational satellite A and B into a chemical transport model Goddard Earth Observing System Chemical model (GEOS-Chem). Monthly inversion experiments were conducted in April, July, and October 2016 to test the performance. The inversion result indicated that the prior inventory from the MEIC model captured ammonia spreads in general; however, it heterogeneously underrated the emission intensity. The increments obtained in the assimilation were as high as 50% in North, East, and Northwest China. The posterior emission inventory presented a regional emission flux consistent with relevant studies. Driven by the optimized source estimate, GEOS-Chem provides superior results than using the prior in the evaluation of the assimilated IASI retrievals and the surface ammonia concentration measured by the ground-based Ammonia Monitoring Network in China.
Global scaling of precipitation extremes using near-surface air temperature and dew point temperature
Authors: Tian Bingru , Chen Hua , Yin Jiabo , Liao Zhen , Li Na , He Shaokun
Published: February 2023

Global warming has altered the energy budget and water cycle processes of the land–atmosphere system, which has resulted in significant effects on precipitation extremes. Previous studies have identified a hook structure between near-surface temperature and precipitation extremes, in which extremes increase with temperature rises and decline thereafter. However, the underlying physical mechanisms of this association remain poorly understood. In this study, global-scale responses of precipitation extremes to near-surface air temperature (SAT) and dew point temperature (DPT) were quantified using the ERA5 reanalysis dataset. The results reveal a hook structure between precipitation extremes scaling and temperature, for both SAT and DPT, over many regions worldwide. The peak point temperature (T
pp) ranges from 15 °C to 25 °C, increasing as latitude decreased. The association of precipitation extremes with SAT is negative in many areas in the tropics, whereas that with DPT is almost always positive; this suggests that moisture supply is the main factor limiting precipitation at higher surface temperatures. The hook structure and scaling rates incompatible with Clausius–Clapeyron scaling are associated with various factors including precipitation duration, total column water vapour, convective available potential energy, and relative humidity.
Spherical vector waves: their generation using a 4π optical array
Authors: Camas-Aquino F , Quinto-Su P A , Jáuregui R
Published: February 2023

Spherical vector waves (SVW) are the natural basis that correlates internal multipole transitions of atomic systems to specific configurations of the electromagnetic field. We theoretically identify the SVW fields that could be approximately generated from incident cylindrical beams using a 4π optical array. A comparison is made between the near electromagnetic field of ideal SVW to that of the spherical spots generated by cylindrical incident laser beams with the selected angular spectra and a finite lens aperture of the 4π system. The fidelity is taken as figure of merit. Some challenges on the implementation of the SVW are briefly discussed.
Photophysics of blue quantum emitters in hexagonal boron nitride
Authors: Zhigulin Ivan , Yamamura Karin , Ivády Viktor , Gale Angus , Horder Jake , Lobo Charlene J , Kianinia Mehran , Toth Milos , Aharonovich Igor
Published: February 2023

Colour centres in hexagonal boron nitride (hBN) have emerged as intriguing contenders for integrated quantum photonics. In this work, we present a detailed photophysical analysis of hBN single emitters emitting at the blue spectral range. The emitters are fabricated by different electron beam irradiation and annealing conditions and exhibit narrow-band luminescence centred at 436 nm. Photon statistics as well as rigorous photodynamics analysis unveils potential level structure of the emitters, which suggests lack of a metastable state, supported by a theoretical analysis. The potential defect can have an electronic structure with fully occupied defect state in the lower half of the hBN band gap and empty defect state in the upper half of the band gap. Overall, our results are important to understand the photophysical properties of the emerging family of blue quantum emitters in hBN as potential sources for scalable quantum photonic applications.