bluuebunny/crossref_metadata_2025 huggingface dataset:
Nano-layered surface plasmon resonance-based highly sensitive biosensor for virus detection: A theoretical approach to detect SARS-CoV-2
Authors: Moznuzzaman Md. , Khan Imran , Islam Md. Rafiqul
Published: June 2021

The outbreak of the coronavirus disease (COVID-19) pandemic has become a worldwide health catastrophe instigated by Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2). Countries are battling to slow the spread of this virus by testing and treating patients, along with other measures such as prohibiting large gatherings, maintaining social distance, and frequent, thorough hand washing, as no vaccines or medicines are available that could effectively treat infected people for different types of SARS-CoV-2 variants. However, the testing procedure to detect this virus is lengthy. This study proposes a surface plasmon resonance-based biosensor for fast detection of SARS-CoV-2. The sensor employs a multilayered configuration consisting of TiO2–Ag–MoSe2 graphene with a BK7 prism. Antigen–antibody interaction was considered the principle for this virus detection. Immobilized CR3022 antibody molecules for detecting SARS-CoV-2 antigens (S-glycoprotein) are used for this sensor. It was found that the proposed sensor’s sensitivity (194°/RIU), quality factor (54.0390 RIU−1), and detection accuracy (0.2702) outperformed those of other single and multilayered structures. This study could be used as a theoretical base and primary step in constructing an actual sensor.
The unusual double-shifted magnetization curves in an exchange-biased perpendicular Co/IrMn system
Authors: Niu Yabin , Wu Huiliang , Huang Yi , Cai Yongyong , Ye Yuchen , Liu Qingfang , Wang Jianbo
Published: June 2021

We observed an unusual double-shifted hysteresis loop in a perpendicular exchange-coupled Co/IrMn system at room temperature, which leads to an uneven exchange bias field in the positive and the negative field. With the thickness of the antiferromagnetic layer ranging from 4.8 to 10.4 nm, the negative exchange bias field is approximately 100 Oe larger than the positive exchange bias field. This result is related to the density of net spins in the antiferromagnetic layer that have pinned on the ferromagnetic layer. In addition, the exchange bias field of this unusual double-shifted hysteresis loop can be adjusted by the magnetic field annealing temperature.
Electrostatic and electrochemical charging mechanisms for electric-double-layer gating media based on a crystalline LaF3 solid electrolyte
Authors: Zhang Xi , Wang Qian , Huang Junwei , Meng Kui , Chen Peng , Zhou Ling , Tang Ming , Zhang Caorong , Dai Xueting , Bi Xiangyu , Qiu Caiyu , Zhang Haijun , Zhao Wei-Wei , Yuan Hongtao
Published: June 2021

The electric-double-layer, constituted on the interface between an electronic conductor and an ionic conductor, enables practical applications of electronic devices and electrochemistry. Specifically, the electric-double-layer interfaces have been widely reported to achieve the insulator–metal transition and interfacial superconductivity in field-effect transistors because of the large electric-double-layer capacitance and high carrier density accumulation. Recently, a crystalline LaF3 solid electrolyte has been shown to be an ideal gate medium candidate for realizing stable electric-double-layer transistors. However, the intrinsic electrostatic and electrochemical mechanisms about LaF3 electric-double-layer interfaces remain elusive. Here, by combining electrochemical-impedance-spectroscopy with low-temperature technology, we demonstrate the temperature–frequency mapping “phase diagram” for the capacitance and dielectric loss at the LaF3/metal interfaces. Two well-distinguished regions correspond to the electrostatic and electrochemical nature, providing a promising guideline for practical device applications based on the crystalline LaF3 solid electrolyte.
Time-resolved two-photon interference of weak coherent pulses
Authors: Kim Heonoh , Kwon Osung , Moon Han Seb
Published: June 2021

The observation of the Hong–Ou–Mandel (HOM)-type two-photon interference (TPI) has played an important role in the development of photonic quantum technologies. The time-resolved coincidence-detection technique has been effectively used to identify and characterize the TPI phenomena of long-coherence optical fields. Here, we report on the experimental demonstration of the TPI of two phase-randomized weak coherent pulses with time-resolved coincidence detection. The mutual coherence time between the two weak coherent lights is determined by applying a frequency noise to one of the two interfering lights. We analyze the HOM-type TPI fringe visibility according to the ratio of the coherence time to the pulse duration.
Transient probability in basins of noise influenced responses of mono and coupled Duffing oscillators
Authors: Cilenti Lautaro , Balachandran Balakumar
Published: June 2021

Duffing systems excited by harmonic excitations and subjected to noise additions are considered, and it is examined whether the noise addition can be used to steer the response from one stable mode to another. To help with this examination, the authors propose a methodology for estimating the probability that a short duration Gaussian white noise can be used to generate or destroy stable modes of a single nonlinear oscillator as well as a set of coupled nonlinear oscillators. This estimation is done by using the path integral method to find the transient joint probability density function at discrete points in time and then integrating the probability density function over the basins of attraction of the responses of the deterministic system. Results are provided and discussed for the single Duffing oscillator and two coupled Duffing oscillators forced by a near resonance harmonic excitation and noise addition. This work can form a basis for carrying out noise influenced energy movement or localization in the arrays of nonlinear oscillators and have relevance for applications in sensors, energy harvesting devices, and more.
Energy decay and blow-up of solutions for a viscoelastic equation with nonlocal nonlinear boundary dissipation
Authors: Li Donghao , Zhang Hongwei , Hu Qingying
Published: June 2021

In this paper, we consider a nonlinear viscoelastic equation with nonlocal nonlinear boundary damping and two nonlinear source terms (boundary and interior). We obtain the global existence of solution via the potential well method. By introducing suitable Lyapunov functionals, using the multiplier method, and constructing convex differential inequality, we establish an explicit and general decay rate result. This improves previous decay results concerning the problem. We also get a finite time blow-up result of solution with positive initial energy under suitable conditions on the initial data and positive memory function. This is the first result for blow-up of the problem with nonlocal nonlinear boundary damping.
Preparation of two-dimensional [Bi2O2]-based layered materials: Progress and prospects
Authors: Liang Yan , Zhou Xuehan , Li Wen , Peng Hailin
Published: June 2021

Two-dimensional (2D) materials have drawn much attention in recent years ascribing to their unique properties associated with atomic thickness. Besides graphene, which has aroused tremendous research interest, other 2D materials such as [Bi2O2]-based layered compounds, i.e., Bi2O2Se, BiOCl, and Bi2Sr2CaCu2Ox, have also been studied widely and show promising application prospects in electronics, optoelectronics, photocatalysis fields, and so on. In this Perspective, we systematically review the progress on preparation methods of 2D [Bi2O2]-based layered materials, discuss the strengths and drawbacks of different methods, and give an outlook toward future research directions.
Scaling law of fish undulatory propulsion
Authors: Yu Yong-Liang , Huang Kai-Jun
Published: June 2021

A scaling formulation is constructed for the hydrodynamic thrust by an undulatory propulsor based on the vortex dynamics. It states that the propulsion thrust is in scale with the square of Strouhal number and the relative speed of undulation and fish forward swimming, which implies an energy flux from the fish body to fluid. The higher the energy flux, the higher is the propulsion fish obtains. The results indicate that the scaling relation holds widely for different undulatory locomotion modes, where the slope factor of “thrust-energy flux” increases monotonously with the wavelength and Reynolds number. The full scaling law of the propulsion depends not only on the Strouhal number and Reynolds number, but also on the wavelength and the undulatory phase speed.
Repulsive inter-layer coupling induces anti-phase synchronization
Authors: Shepelev Igor A. , Muni Sishu S. , Schöll Eckehard , Strelkova Galina I.
Published: June 2021

We present numerical results for the synchronization phenomena in a bilayer network of repulsively coupled 2D lattices of van der Pol oscillators. We consider the cases when the network layers have either different or the same types of intra-layer coupling topology. When the layers are uncoupled, the lattice of van der Pol oscillators with a repulsive interaction typically demonstrates a labyrinth-like pattern, while the lattice with attractively coupled van der Pol oscillators shows a regular spiral wave structure. We reveal for the first time that repulsive inter-layer coupling leads to anti-phase synchronization of spatiotemporal structures for all considered combinations of intra-layer coupling. As a synchronization measure, we use the correlation coefficient between the symmetrical pairs of network nodes, which is always close to −1 in the case of anti-phase synchronization. We also study how the form of synchronous structures depends on the intra-layer coupling strengths when the repulsive inter-layer coupling is varied.
Vitality in relation to litter size of crossbred pigs and the effect of the terminal sire line
Authors: Elbert K. , Matthews N. , Wassmuth R. , Tetens J.
Published: June 2021

Context Most research on sire lines is linked to growth and carcass traits. Only a limited number of field trials explore the effect of sire line on piglet vitality, litter size and the interactions between these traits. Aim The aim of this study was to examine the effect of sire line on the growth performance and vitality of progeny from birth to weaning and to evaluate the lines with respect to their impact on litter size. Methods Data included 150 litters of a Synthetic sire line (A) and 154 of a Piétrain sire line (B), with 4209 piglets born alive, which resulted from matings to 337 dams (Camborough PIC). The numbers of total born and born alive piglets per litter were recorded. Within 24 h after birth, piglet individual birthweight (BWbirth), sex (male/female) and body temperature (BT) were also recorded. At weaning, mortality rates and weaned pigs per sow were registered. At the day of weaning, 665 randomly chosen pigs were individually weighed. Weaning weights (WW) were used to calculate the weaning average daily gain (WADG). Key results Sire line significantly affected number of total born (P < 0.0001), number born alive (P < 0.01) and number of weaned pigs per sow (P < 0.01). Across lines, each additional piglet per litter resulted in a 31.2 g decline in BWbirth (P < 0.001). Larger litter sizes, higher BWbirth (P < 0.01) and piglets with a lower BT (P < 0.0001) were detected in litters of Sire line B compared with litters of Sire line A. No differences between lines were detected for WADG, WW and pre-weaning mortality (P > 0.05). A positive correlation between birthweight and WW resulted in a correspondingly higher WADG (P < 0.0001). Overall, heavier BWbirth piglets had a higher BT (P < 0.0001). Conclusions The present study indicates that Sire line B would offer a possibility to maintain litter size at a high level and, simultaneously, achieve higher BWbirth, with consequently more vital piglets. Implication It is important to emphasise that further selection for litter size in dam lines is not indicated in terms of animal welfare but also production efficiency. Instead, it seems feasible to follow the above strategy and stabilise litter size at a high level, while at the same time breeding for vitality and survivability in sire lines.
Carbonate-hosted microbial communities are prolific and pervasive methane oxidizers at geologically diverse marine methane seep sites
Authors: Marlow Jeffrey J. , Hoer Daniel , Jungbluth Sean P. , Reynard Linda M. , Gartman Amy , Chavez Marko S. , El-Naggar Mohamed Y. , Tuross Noreen , Orphan Victoria J. , Girguis Peter R.
Published: June 2021

Significance

Methane is a strong greenhouse gas that plays a key role in Earth’s climate. At methane seeps, large amounts of methane move upward through the seafloor, where microbial communities consume much of it. A full accounting of methane’s sources and sinks has evaded researchers—in part, perhaps, because key habitats including carbonate rock mounds have been largely neglected. We sampled seven methane seeps representing four geological settings and found that all sites had rock-hosted microbes capable of consuming methane; in lab-based incubations, some did so at the highest rates reported to date. We demonstrate several factors that help determine a sample’s methane-consuming potential and propose that carbonate rocks at methane seeps may represent a methane sink of far-reaching importance.
Tailoring electrocatalytic activity of in situ crafted perovskite oxide nanocrystals via size and dopant control
Authors: Harn Yeu-Wei , Liang Shuang , Liu Shuanglong , Yan Yan , Wang Zewei , Jiang Jun , Zhang Jiawei , Li Qiong , He Yanjie , Li Zili , Zhu Lei , Cheng Hai-Ping , Lin Zhiqun
Published: June 2021

Significance

The ability to scrutinize the correlation of dimension, composition, and dopant to electrocatalytic performance renders the development of highly active electrocatalysts. This work reports a general and robust strategy for crafting uniform perovskite oxide nanoparticles (i.e., BaTiO
3
and La- and Co-doped BaTiO
3
) with controlled sizes and dopant compositions by employing amphiphilic star-like diblock copolymers as nanoreactors. Their size- and dopant-dependent oxygen reduction reaction (ORR) performances are unveiled. Particularly, La- and Co-doped BaTiO
3
nanoparticles exhibit markedly improved ORR activities over the pristine counterparts due to reduced free energy barrier of ORR and increased conductivity as substantiated by density functional theory. The nanoreactor strategy could be conveniently extended to yield various functional nanomaterials of interest with tailored sizes and compositions for electrocatalysis.
Epigenetic inheritance of DNA methylation changes in fish living in hydrogen sulfide–rich springs
Authors: Kelley Joanna L. , Tobler Michael , Beck Daniel , Sadler-Riggleman Ingrid , Quackenbush Corey R. , Arias Rodriguez Lenin , Skinner Michael K.
Published: June 2021

Significance

Environmental factors can promote phenotypic variation through alterations in the epigenome and mediate adaptation of an organism to the environment. Observations suggest the adaptation ofPoecilia mexicanafish to toxic, hydrogen sulfide–rich environments in southern Mexico may, in part, be promoted through epigenetic DNA methylation alterations that became generationally stable and are inherited to subsequent generations independent of the environment. Environmental epigenetics may provide an important mechanism mediating adaptation in this species. This is an observation that the epigenome is stably inherited generationally through the germline after the removal of an environmental stressor (i.e., hydrogen sulfide) from a wild population.
Validating model-based Bayesian integration using prior–cost metamers
Authors: Sohn Hansem , Jazayeri Mehrdad
Published: June 2021

Significance

Over the last decade, Bayesian modeling has emerged as a unified approach for capturing a wide range of behaviors such as perceptual illusions, cognitive decision making, and motor control. Despite its remarkable success, the Bayesian approach has been challenged by the issue of model identifiability; that is, the components of a Bayesian model (e.g., prior and cost function) are not uniquely determined by the behavior. Here, we create an experimental paradigm that provides a way to adjudicate whether and when humans build and use the internal models of priors and cost functions. Our work provides a path toward resolving the controversies surrounding the notion of the Bayesian brain.
Restriction of SARS-CoV-2 replication by targeting programmed −1 ribosomal frameshifting
Authors: Sun Yu , Abriola Laura , Niederer Rachel O. , Pedersen Savannah F. , Alfajaro Mia M. , Silva Monteiro Valter , Wilen Craig B. , Ho Ya-Chi , Gilbert Wendy V. , Surovtseva Yulia V. , Lindenbach Brett D. , Guo Junjie U.
Published: June 2021

Significance

A large variety of RNA viruses, including the novel coronavirus SARS-CoV-2, contain specific RNA structures that promote programmed ribosomal frameshifting (PRF) to regulate viral gene expression. From a high-throughput compound screen, we identified a PRF inhibitor for SARS-CoV-2 and found that it substantially impeded viral replication in cultured cells. Interestingly, the compound could target not only SARS-CoV-2 but also other coronaviruses that use similar RNA structures to promote frameshifting. These results suggest targeting PRF is a plausible, effective, and broad-spectrum antiviral strategy for SARS-CoV-2 and other coronaviruses.
AI-based spectroscopic monitoring of real-time interactions between SARS-CoV-2 and human ACE2
Authors: Ye Sheng , Zhang Guozhen , Jiang Jun
Published: June 2021

Significance

The COVID-19 caused by SARS-CoV-2 virus has posed a tremendous threat to human health. The interactions between human angiotensin-converting enzyme 2 and the spike glycoprotein of SARS-CoV-2 hold the key to understanding the molecular mechanism to develop treatment and vaccines. However, the simulation of these interactions in fluctuating surroundings is challenging because it requires many electronic structure calculations at the quantum mechanics level for a large number of representative configurations. We report a machine learning protocol that can efficiently predict the IR spectra of SARS-CoV-2 with high efficiency and characterize fine changes in IR spectra associated with variations of protein secondary structures. Machine learning provides a cost-effective tool for monitoring of real-time interactions between the SARS-CoV-2 and human ACE2.
Attention, awareness, and the right temporoparietal junction
Authors: Wilterson Andrew I. , Nastase Samuel A. , Bio Branden J. , Guterstam Arvid , Graziano Michael S. A.
Published: June 2021

Significance

We all intuitively know what it is to be subjectively aware of something. For decades, psychologists have also studied the brain’s mechanisms of directing attention. But awareness and attention are not the same and can be separated. How do they relate? Here, we show that a part of the brain, the right temporoparietal junction, may be involved in a specific relationship in which awareness of an item permits the control of attention on that item.
From controversy to complexity
Authors: Dam Helle V.
Published: June 2021

A replication of previous research, this study sets out to re-examine language choice in note-taking for
consecutive conference interpreting – a topic that is widely believed to be subject to conflicting evidence. Extending the
existing database considerably, the study draws on data from seven different consecutive interpreting tasks involving five
different languages and both interpreting directions (B into A and A into B) performed by ten participants with seven different
language combinations. Interpreters’ notes from these performances served as the main data of the study, which was complemented by
questionnaire data to form a mixed-methods design. Analyses of the interpreters’ notes identified the A language as by far the
strongest determinant of language choice, above and beyond other language categories; this confirmed the results of the replicated
research. The questionnaire data, however, did not mirror the patterns found in the interpreting data consistently, suggesting a
complex interplay of behavior and norms. The article concludes with a discussion of these and previous findings, arguing for the
topic of language choice in note-taking to be reframed as one of complexity rather than contradiction.
Active edible coatings in meat
Authors: Forato Lucimara A. , Bernardes-Filho Rubens , Colnago Luiz A. , Nassu Renata T.
Published: June 2021

Meat is a perishable product due to its protein and high-water activity (Aw) and is thus prone to microbial and oxidative processes, which lead to spoilage and undesirable changes in meat physicochemical characteristics. Edible coatings, combined with antioxidant and antimicrobial substances, have been used to improve meat shelf life by creating an oxygen barrier against lipid oxidation, acting as an antimicrobial agent, and to keep meat color. Here, we reviewed the use of active edible coatings and their effects on physicochemical and sensory characteristics of chicken, pork, beef, lamb meat, and fish.
Generalized Chern numbers based on open system Green’s functions
Authors: Farias M Belén , Groenendijk Solofo , Schmidt Thomas L
Published: June 2021

We present an alternative approach to studying topology in open quantum systems, relying directly on Green’s functions and avoiding the need to construct an effective non-Hermitian (nH) Hamiltonian. We define an energy-dependent Chern number based on the eigenstates of the inverse Green’s function matrix of the system which contains, within the self-energy, all the information about the influence of the environment, interactions, gain or losses. We explicitly calculate this topological invariant for a system consisting of a single 2D Dirac cone and find that it is half-integer quantized when certain assumptions about the self-energy are made. Away from these conditions, which cannot or are not usually considered within the formalism of nH Hamiltonians, we find that such a quantization is usually lost and the Chern number vanishes, and that in special cases, it can change to integer quantization.
Predicting the evolution of photospheric magnetic field in solar active regions using deep learning
Authors: Bai Liang , Bi Yi , Yang Bo , Hong Jun-Chao , Xu Zhe , Shang Zhen-Hong , Liu Hui , Ji Hai-Sheng , Ji Kai-Fan
Published: June 2021

The continuous observation of the magnetic field by the Solar Dynamics Observatory (SDO)/Helioseismic and Magnetic Imager (HMI) produces numerous image sequences in time and space. These sequences provide data support for predicting the evolution of photospheric magnetic field. Based on the spatiotemporal long short-term memory (LSTM) network, we use the preprocessed data of photospheric magnetic field in active regions to build a prediction model for magnetic field evolution. Because of the elaborate learning and memory mechanism, the trained model can characterize the inherent relationships contained in spatiotemporal features. The testing results of the prediction model indicate that (1) the prediction pattern learned by the model can be applied to predict the evolution of new magnetic field in the next 6 hours that have not been trained, and predicted results are roughly consistent with real observed magnetic field evolution in terms of large-scale structure and movement speed; (2) the performance of the model is related to the prediction time; the shorter the prediction time, the higher the accuracy of the predicted results; (3) the performance of the model is stable not only for active regions in the north and south but also for data in positive and negative regions. Detailed experimental results and discussions on magnetic flux emergence and magnetic neutral lines finally show that the proposed model could effectively predict the large-scale and short-term evolution of the photospheric magnetic field in active regions. Moreover, our study may provide a reference for the spatiotemporal prediction of other solar activities.
Search for variable stars in the open cluster NGC 1245
Authors: Shen Dong-Xiang , Zhang Yu , Li Chun-Yan , Zeng Xiang-Yun , Lü Guo-Liang , Zhu Chun-Hua , Hu Qing-Shun , Liu Jin-Zhong
Published: June 2021

We used the Nanshan 1m telescope of Xinjiang Astronomical Observatory to investigate variable stars in the region of NGC 1245. We detected 55 variable stars in the field of view, 42 of them are newly discovered: six binaries, 22 pulsating stars, 14 unclassified variables. We discussed the physical properties and classifications of the variable stars through their light curves. The cross-matching with the members catalog of NGC 1245 suggests that 10 variable stars are identified as probable cluster members, which including one EW type binary, eight δ Scuti stars, and an unknown type variable star. Since the difference of the members catalog of the cluster and the limitations of the instrument, there are some huge differences in the variable list of NGC 1245 compared with the previous work.
Magneto-acoustic waves in magnetic twisted flux tubes
Authors: Wu Wei , Sych Robert , Chen Jie , Su Jiang-Tao
Published: June 2021

At present, many works about MHD wave diagnostics in magnetic flux tubes are based on some pioneering works not considering the contributions of magnetic twist. Other works considered the effect on MHD waves, but the dispersion relationship they presented only gave the wave modes of m = 0,1,2… The kink mode of m = –1 was absent. Therefore, in this work we present a complete dispersion relationship that includes both magnetic twist and the wave mode of m = –1. Analogous to the m = +1 wave mode, the mode of m = –1 also exhibits the mode change at finite kr
0, from body to surface mode. The phase speeds of this mode are usually less than those of m = +1 mode. The harmonic curves of m = ± 1 modes in dispersion relationship diagrams are approximately symmetric in respect to a characteristic velocity, e.g. the tube velocity in flux tubes. Based on the present dispersion relationship, we revisit the issue of spiral wave patterns in sunspots and find that the magnetic twist has no great influence on their morphology in the frame of linear perturbation analysis.
Heavy element contributions of rotating massive stars to interstellar medium
Authors: Wu Rui-Qing , Zhu Chun-Hua , Lü Guo-Liang , Wang Zhao-Jun , Liu He-Lei
Published: June 2021

Employing the stellar evolution code Modules for Experiments in Stellar Astrophysics (MESA), we calculate yields of heavy elements from massive stars via stellar wind and core−collapse supernova (CCSN) ejecta to the interstellar medium (ISM). In our models, the initial masses (Mini) of massive stars are taken from 13 to 80M⊙, their initial rotational velocities (V) are 0, 300 and 500 km s−1, and their metallicities are [Fe/H] = –3, –2, –1 and 0. The yields of heavy elements coming from stellar winds are mainly affected by stellar rotation which changes the chemical abundances of stellar surfaces via chemically homogeneous evolution, and enhances mass-loss rate. We estimate that the stellar wind can produce heavy element yields of about 10−2(for low metallicity models) to a mass of severalM⊙(for low metallicity and rapid rotation models). The yields of heavy elements produced by CCSN ejecta also depend on the large amount of remnant mass which is mainly determined by the mass of the CO-core. Our models calculate that the yields of heavy elements produced by CCSN ejecta can get up to severalM⊙. Compared with stellar wind, CCSN ejecta has a greater contribution to the heavy elements in ISM. We also compare the56Ni yields calculated in this work with the observational estimate. Our models only explain the56Ni masses produced by faint SNe or normal SNe with progenitor mass lower than about 25M⊙, and greatly underestimate the56Ni masses produced by stars with masses higher than about 30M⊙.
Extreme space weather events caused by super active regions during solar cycles 21-24
Authors: Le Gui-Ming , Liu Gui-Ang , Zhao Ming-Xian , Mao Tian , Xu Ping-Guo
Published: June 2021

Extreme space weather events including ≥X5.0 flares, ground level enhancement (GLE) events and super geomagnetic storms (Dst ≤ –250 nT) caused by super active regions (SARs) during solar cycles 21–24 were studied. The total number of ≥X5.0 solar flares was 62, among which 41 were X5.0-X9.9 flares and 21 were ≥X10.0 flares. We found that 83.9% of the ≥X5.0 flares were produced by SARs; 78.05% of the X5.0-X9.9 and 95.24% of the ≥X10.0 solar flares were produced by SARs; 46 GLEs were registered during solar cycles 21–24, and 25 GLEs were caused by SARs, indicating that 54.3% of the GLEs were caused by SARs; 24 super geomagnetic storms were recorded during solar cycles 21–24, and 12 of them were caused by SARs, namely 50% of the super geomagnetic storms were caused by SARs. We ascertained that only 29 SARs produced ≥X5.0 flares, 15 SARs generated GLEs and 10 SARs triggered super geomagnetic storms. Of the 51 SARs, only 33 SARs produced at least one extreme space weather event, while none of the other 18 SARs could trigger an extreme space weather event. There were only four SARs and each of them generated not only a ≥X5.0 flare, but also a GLE event and a super geomagnetic storm. Most of the extreme space weather events caused by the SARs appeared during solar cycles 22 and 23, especially for GLE events and super geomagnetic storms. The longitudinal distributions of source locations for the extreme space weather events caused by SARs were also studied.
The impact of real-time fMRI denoising on online evaluation of brain activity and functional connectivity
Authors: Misaki Masaya , Bodurka Jerzy
Published: June 2021

Objective. Comprehensive denoising is imperative in functional magnetic resonance imaging (fMRI) analysis to reliably evaluate neural activity from the blood oxygenation level dependent signal. In real-time fMRI, however, only a minimal denoising process has been applied and the impact of insufficient denoising on online brain activity estimation has not been assessed comprehensively. This study evaluated the noise reduction performance of online fMRI processes in a real-time estimation of regional brain activity and functional connectivity. Approach. We performed a series of real-time processing simulations of online fMRI processing, including slice-timing correction, motion correction, spatial smoothing, signal scaling, and noise regression with high-pass filtering, motion parameters, motion derivatives, global signal, white matter/ventricle average signals, and physiological noise models with image-based retrospective correction of physiological motion effects (RETROICOR) and respiration volume per time (RVT). Main results. All the processing was completed in less than 400 ms for whole-brain voxels. Most processing had a benefit for noise reduction except for RVT that did not work due to the limitation of the online peak detection. The global signal regression, white matter/ventricle signal regression, and RETROICOR had a distinctive noise reduction effect, depending on the target signal, and could not substitute for each other. Global signal regression could eliminate the noise-associated bias in the mean dynamic functional connectivity across time. Significance. The results indicate that extensive real-time denoising is possible and highly recommended for real-time fMRI applications.
Compactible Level Measurement and Forewarning in Petrol Station
Authors: Moorthy V Prasanna , Subramanian Suntrakanesh , Balaji O S P
Published: June 2021

It is known that India is the third-largest country in fossil fuel consumption, and the economy of India dramatically depends on the transportation of goods and services which require fuel. Petrol stations should ensure the correct fuel stock and restore the fuel on time once it gets exhausted. Thus, the customer’s needs get satisfied. Generally, the level measurement in fuel storage tanks is carried out by physical methods which involve dipsticks or using some level sensors, float switch, and load cell. Dipsticks are more often used in level measurement. The usage of dipsticks involves a human operator removing and read the dipstick scale. The measured data is communicated to the refill manager through phone calls, and the petrol station gets refilled. The refilling of petrol station may get late due to improper communication and late transportation of fuel vehicles when stuck in traffic. This work aims to overcome the material problem and improve efficiency and accuracy in the level measurement of fuel by introducing automation in measurement and communication. The depth of the fuel tank is estimated by a level sensor accompanied by a Wi-fi module to bring out automation. The measured data can be accessed directly by the user through a telegram app. The level of the fuel tank is automatically indicated. The dynamically changing data of the fuel tank can also be acquired by using the telegram app. The refill manager will be aware of the fuel level, and fuel can be restored on time. This product will be very useful in remote areas. This product has vast potential and will play a significant role in fuel measurement for key oil companies.
AIOT based Real Time Environment Monitoring and Tracking System for Soldiers using SN-MQTT Protocol
Authors: Manikandan T , Ranjani J , V Ramnya , Preethi S
Published: June 2021

In the crisis filled world, it is necessary to protect our Country and its resources. Where a strong military force will enable in safeguarding the nation security, wealth and our valuable lives too. Soldiers are not only involved in providing protection against the military attacks but also plays a crucial role in resolving problems thereby maintaining prevalence of peace in the country. Therefore, it is necessary to safeguard and protect soldiers from dangers as they are the guardians to enrich the prosperity of one’s country. The proposed project focuses on monitoring the soldier’s environmental attacks like detection of gun firing attacks, toxic gas detection, and emergency alert in case of threats. Followed by creating a virtual fence using Global Positioning System (GPS) to track and guard them within the safer zone and with inclusion of two-way wireless communication between the soldier & the surveillance unit using Wi-Fi Module in case of emergency return from the battle field thereby protecting them from the possibilities of danger. The technologies in particular Artificial Intelligence of Things i.e. the collaboration of Internet of Things (IoT) with deep learning (RNN-LSTM Model) helps in achieving information transfer between soldier and administrator followed by prediction of toxic gas presence in the atmosphere. The Administrator at the surveillance unit will monitor the real time status of the soldier in the webpage created using Node Red Programming Tool where the data are carried out by means of Sensor Networks - Message Queuing Telemetry Transport Protocol (MQTT). Thus this system ensures the security of the soldier.
IoT based Touch-free Attendance System (ITAS)
Authors: Tamilselvan S , Ramesh R , Niveda R , Poonguzhali P , Dharani S
Published: June 2021

In this paper, we are proposing a contactless temperature measuring and attendance monitoring system because of the pandemic COVID-19. This design is developed using Node MCU, MLX90614 Infrared Thermometer, RFID Reader, and Ultrasonic Sensor. It measures body temperature with an infrared temperature sensor without any physical contact. An RFID card reader is used for scanning the identity card. The ID number and the temperature of students are uploaded into the webpage. This webpage can be monitored over the internet. The details such as Entry time, ID number, No. of students and temperature measurements are stored in the server and displayed in webpage. An Ultrasonic Sensor is used to measure the distance between the sensor and the person. The temperature sensor can measure the temperature when the distance between the sensor and person is around 10 cm for better accuracy. This system is essential in this pandemic situation to avoid the infections.
Low Power and Efficient Floating-Point Architecture for Division and Square Root
Authors: Hema Priya K , Arulmurugan L , Ramesh R , Nithya B
Published: June 2021

The modern processor requires multiple dedicates, fully pipelined architecture uses instructional level parallelism. So, this pipeline is very important in it. The proposed system is implemented using the fully pipelined architecture FPU in FPGA’s. Square root and division have many complications in DSP but it is important to implement in FPGA because it is so tough. Some of them will not implement the add and multiply components when compared to the slow or large which will match the real time applications. In every clock cycle, pipeline should have the capability of accepting the square root and divider. In single precision floating point Verilog code is written and implemented using spartan 6 FPGA for sqrt/division. The operation latency and issue rate have 18 clock cycles and 15 clock cycles. It uses many adders/subtractors in other high pipelined implementations. The operation latency and issue rate have 15 clock cycles and 1 clock cycles. It reduces power dissipation. It has some advantages like area utilization will be less and latency bound.
Performance Analysis of InP based Composite Channel e-mode HEMT Device for High Frequency Applications
Authors: Krishna M Vijay , Rahool M M , Kumar K Dinesh , Raj A Daniel , Kumar R Saravana
Published: June 2021

High Electron Mobility Transistor (HEMT) is presently a very important part in the electronics industries for high frequency applications and for low power applications. In this approach, single gate enhancement mode composite channels of In0.7Ga0.3As/InAs/In0.7Ga0.3As HEMT devices are simulated and analyzed for low power operations which leads to strong DC and RF performance. This can be achieved by working on the composite channel which was lattice matched, gate which was recessed and length of the gate which was optimized. In this paper, for various lengths of the gate with constant barrier thickness, the performance of the device is analyzed symmetrically with the specialized device dimensions with thickness of the barrier (TB) = 2nm, thickness of the channel (TCH) = 15nm. The length of the gate can be reduced which supports in decreasing the drain resistance, effects of capacitance and improved average electron velocity in the gate. And this in turn results in the best performance of the device metrics with the values, trans-conductance (gm) as 1741 μS/μm, drain current (Id) as 0.553574 mA/μm, cut-off frequency (fT) as 431 GHz, maximum frequency of oscillations (fmax) as 557 GHz.
Improving the Performance of Layered Iterative minsum Approximation Message Passing Decoding Algorithm for 5G NR LDPC Codes
Authors: Vigneswari P. , Sivakumari S.
Published: June 2021

In order to cater to the needs of the 5G standard, one of the prominent solutions in terms of high coding gain, high throughput and low power dissipation is the 5G NR LDPC (New Radio Low Density Parity Check) codes which have been adopted by 5G Standard. LDPC codes are the successful Third Generation Forward Error Correcting codes. An Efficient decoder is the key to the success of any Error Correcting Code. LDPC codes are one whose parity check matrix have a very few non zero entries. 5G NR LDPC codes are constructed by Protographs or base graphs and are block structured. This paper improves the performance of Layered Iterative minsum Approximation Message Passing decoding Algorithm using Rate Matching, Fixed Point Quantization and Offset minsum techniques. Rate Matching is to maintain the exact number of encoded blocks with in the TTI. Simulation of this algorithm with BPSK encoding over AWGN channel shows that BER of 10-3 gives Eb/No of~2 dB for the block length of 105.
DWT Based QR Steganography
Authors: Priya K. , Roomi S. Mohamed Mansoor , Maheswari P. Uma , Suganya R.
Published: June 2021

Data security pays more attention in most of the communication fields. Image steganography is one of the leading data security techniques that provides confidentiality with high embedding capacity and high steganography image quality. This work proposes Discrete Haar Wavelet Transform (DWT-H) and bitwise operations-based embedding technique to embed secret QR-code message in the cover image and extraction of QR-code secret message is also carried out by the same methodology. The efficiency of the proposed method is estimated by Mean Square Error (MSE) and Peak Signal to Noise Ratio (PSNR). This technique provides less MSE and PSNR in the range of 31dB to 44dB and extracts QR code image up to version 40. The results of the proposed method provide the practical feasibility for QR-coded-based security applications with less time and high accuracy.
Multiple Protocol Converter
Authors: Sivaraj D. , Ragavi G.
Published: June 2021

In the modern world, IoT plays a vital role. In general, each device works on a different protocol. The problem of achieving communication between two processes across a network or an internetwork is considered. The notion of logical connectivity between processes in a protocol is formalized. The problem of constructing a protocol converter to achieve interoperability between processes that implement different protocols is addressed. A formal model is presented, based on the theory of protocol projection, for reasoning about the semantics of different protocols and conversions between them. This paper ‘Multiple Protocol Converter’ aims in converting from one protocol to any other protocol as per the requirement which supports different devices to interconnect with IoT seamlessly.
IoT based Smart Retail System with Social Distancing for Covid19 Outbreak
Authors: Thilagavathi S , Nivethitha K S , Preeti P , Vikram D T
Published: June 2021

Covid19 pandemic caused by infection with the severe acute respiratory syndrome corona virus2 is continuously spreading all over the world. The impact of covid19 has been fallen on almost all sectors of development including retail which plays a major role in day to day life. In this paper, we proposed an efficient methodology to create a safe environment of people in retail that contributes to public safety. The proposed smart retail system is focused on the real time monitoring of shopping malls which includes grocery, departmental stores, clothing shops, jewellery shops and shops with food essential products. At first a Mobile Application is developed using Android Studio for prebooking of shopping by users/customers. Using Anaconda Navigator a deep learning trained architecture is developed on distinguishing people with and without face mask. A wearable device is developed using ultra wide band radio technology to ensure safe social distancing which would alert customers as soon as the violation of social distancing is detected. The smart retail system also includes IoT based smart shopping cart with RFID sensors for the customers to check for the availability of items in the web server via Nodemcu and for automatic bill payment. The proposed methodology is also suitable for Religious places, Cinema Theatre, Training centres and Browsing centres.
Synthesis and characterization of resin lead acetate composites and ability test of X-ray protection
Authors: Septiano A F , Sutanto H , Susilo
Published: June 2021

Radiation is widely used in various fields, especially in the health sector, but radiation can cause dangers. Including genetic mutations, therefore we need a system to protect from these dangers. One of the radiation protection systems is to use lead glass. In this research, an alternative substitute for lead glass is offered where a composite resin has been made with the addition of lead acetate variations. Several tests have been carried out including the absorption of x-ray radiation reaching 100% obtained at a sample thickness of 13mm with a ratio of 50% resin and 50% lead acetate. In SEM testing, it was obtained dense morphological results and EDX testing showed a balance of constituent compounds between Carbon (C), Oxygen (O) and Lead (Pb) in this sample.
Analysis of the combination aspects of creativity level in product design for physics students in basic physics learning
Authors: Edie S S , Krismonika Z
Published: June 2021

The 21st Century skills that need to be reached at the top of the learning process according to the revised Bloom Taxonomy is creativity. Creativity can be reviewed through the 4P approach of Person, Press, Process, and Product. The analysis of product creativity can be categorized into five aspects, it is imitation, variation, combination, transformation, and original creation. This research only looks at the combination aspect. Combination is taking two existing works and then combining them. The method of this research is quantitative with descriptive approach. The research was conducted by giving an assignment to make a combination product design from the LCC bell. Design was assessed by 35 college student participants and researchers uses instruments that have been validated and reliabel. The results of the assessment were analyzed using simple descriptive statistics in the form of means. The results of the analysis show that the combination creativity of products design Unnes Physics students is in the very high category. The assessment obtained was 5.7 in the score range 1-7.
Critical thinking skills assessment instrument in physics subjects: how to develop a four tier diagnostic test?
Authors: Waluyo A A , Hartono  , Sulhadi
Published: June 2021

Critical thinking is a thinking skills that involves a process of reasoning and reflective thinking that cannot be directly observed, so it requires a separate assessment instrument. This research is a development research that aims to produce an instrument for assessing critical thinking skills that can measure students’ critical thinking skills and ilustrate the interconnectedness between aspects of critical thinking skills. The sample was selected using random sampling technique of 109 students in the trial stages and 136 students in the implementation stages. Data analysis was performed through several test that is content validity, construct validity, reliability, the level of students’ critical thinking skills, and analysis of variance. The validity test shows that the instrument contains 4 factors that match theorized and the content validity score shows that can be used. While the reliability test shows that the Cronbach Alpha coefficient of 0,820. The tier of critical thinking skills of high school students in Banyumas Regency is less. Analysis of the relationship aspects of critical thinking skills shows that each aspect of critical thinking skills are interconnected with the analysis aspect as the basic and the conclusion and evaluation aspects as the culmination of being mutually sustainable in producing solutions.