bluuebunny/crossref_metadata_2025 huggingface dataset:
Total Knee Arthroplasty for Osteoarthritis Is Uncommon after Intralesional Curettage in Giant Cell Tumor of Bone
Authors: Lee Linus , Buac Neil , Colman Matthew W. , Gitelis Steven , Blank Alan T.
Published: July 2022

Giant cell tumor of bone (GCTB) is most often treated with intralesional curettage; however, periarticular lesions have been shown to increase risk for osteoarthritis. Additionally, the location of these lesions may occasionally preclude a joint-sparing procedure in recurrent tumors. This study sought to investigate rates of secondary arthroplasty in long-term follow-up of knee GCTB. Cases of knee GCTB treated at our institution were reviewed. Rates of recurrence and secondary arthroplasty were recorded, and Kaplan-Meier survival analyses were performed. The records of 40 patients were reviewed. Local recurrence occurred in 25% of patients. The 1-, 5-, and 10-year recurrence-free survival (RFS) probability was 87.4% (95% CI, 77.0–97.7), 72.4% (95% CI, 57.6–87.2), and 72.4% (95% CI, 57.6–87.2), respectively. Function improved after surgery with a mean preoperative MSTS score of 14.9 (standard deviation [SD] 8.4) and mean postoperative MSTS score of 25.1 (SD 5.6) (p <0.001). Three patients had evidence of radiographic osteoarthritis at the last follow-up though they did not require arthroplasty. Arthroplasty was performed as a secondary procedure in six patients. Five patients underwent arthroplasty for recurrent tumors after initial treatment with curettage and one patient underwent patellar arthroplasty for osteoarthritis after initial treatment with an allograft composite arthroplasty. Arthroplasty is performed as a secondary procedure in patients with GCTB at a relatively infrequent rate and more often for cases of recurrent disease than for osteoarthritis. Overall, patients treated for GCTB have improved functional outcomes after surgery than before. Large, multi-institutional studies may be required to assess the incidence of secondary osteoarthritis requiring arthroplasty as this was an infrequent finding in our cohort.
A Study on Liaison between Boey Score and Perforated Peptic Ulcer in View of Postoperative Morbidity and Mortality
Authors: Shah Jaimin D. , Modi Jatinkumar B.
Published: July 2022

Introduction

Several factors associated with poor outcome in perforated peptic ulcer have been identified: delay in diagnosis, coexistent medical illness, shock on admission, leukocytosis, and old age. Such factors increase morbidity and mortality in perforated peptic ulcer disease. Careful resuscitation and perioperative optimization play a significant role in reducing morbidity and mortality associated with perforated peptic ulcer disease.

Methods

A prospective study of 60 cases who were operated for perforated peptic ulcer was done at Sheth L.G. Municipal General Hospital affiliated with AMCMET Medical College & Research Centre, Ahmedabad. Categorization of these patients was done according to Boey score and their outcome was accessed.

Objective

The aim of this study was to appraise and analyze Boey score in operated cases of perforated ulcer disease.

Results

The morbidity and mortality rate in this study were 31.67% and 11.67%, respectively. The morbidity rate increased gradually with increase in Boey score: 8.69, 36.84, 50, and 62.5% for 0, 1, 2, and 3 score, respectively (p < 0.01). The mortality rate was increased progressively with increasing Boey score: 0, 5.26, 30, and 37.5% for 0, 1, 2, and 3 score, respectively, and this relationship was statistically significant (p-value < 0.01). The mean duration of hospital stay was 9.43 ± 4.10 days and p-value was less than 0.001. The area under curve in receiver-operating characteristic curve analysis was 0.854 and 0.751 for mortality and morbidity, respectively.

Conclusion

Boey score is simple, clinically relevant and can precisely predict postoperative morbidity and mortality and the length of hospital stay.
The Abraham–Lorentz force and the time evolution of a chaotic system: The case of charged classical and quantum Duffing oscillators
Authors: Krok Kamila A. , Durajski Artur P. , Szczȩśniak Radosław
Published: July 2022

This paper proves that the Abraham–Lorentz (AL) force can noticeably modify the trajectories of the charged Duffing oscillators over time. The influence of the reaction force on the oscillator evolution is strongly enhanced if the system is considered at the level of quantum mechanics. For example, the AL force examined within the scope of Newtonian description can change the trajectory of the Duffing oscillator only if it has the mass of an electron. However, we showed that when quantum corrections along with the nondeterministic contributions are taken into account, the reaction force of the electromagnetic field affects noticeably even the oscillator with a mass equal to the mass of the 82+20Pb ion. The charged Duffing oscillators belong to the class of systems characterized by the chaotic nondeterministic dynamics. In classical terms, the nondeterministic behavior of the discussed systems results from the breaking of the causality principle by the AL force.
Reassessing the potential of TlCl for laser cooling experiments via four-component correlated electronic structure calculations
Authors: Yuan Xiang , Pereira Gomes André Severo
Published: July 2022

Following the interest in the experimental realization of laser cooling for thallium fluoride (TlF), determining the potential of thallium chloride (TlCl) as a candidate for laser cooling experiments has recently received attention from a theoretical perspective [Yuan et al., J. Chem. Phys. 149, 094306 (2018)]. From these ab initio electronic structure calculations, it appeared that the cooling process, which would proceed from transitions between a3Π0+ and X1Σ0+ states, had as a potential bottleneck the long lifetime (6.04 µs) of the excited state a3Π0+, that would make it very difficult to experimentally control the slowing zone. In this work, we revisit the electronic structure of TlCl by employing four-component Multireference Configuration Interaction (MRCI) and Polarization Propagator (PP) calculations and investigate the effect of such approaches on the computed transition dipole moments between a3Π0+ and a3Π1 excited states of TlCl and TlF (the latter serving as a benchmark between theory and experiment). Whenever possible, MRCI and PP results have been cross-validated by four-component equation of motion coupled-cluster calculations. We find from these different correlated approaches that a coherent picture emerges in which the results of TlF are extremely close to the experimental values, whereas for TlCl the four-component calculations now predict a significantly shorter lifetime (between 109 and 175 ns) for the a3Π0+ than prior estimates. As a consequence, TlCl would exhibit rather different, more favorable cooling dynamics. By numerically calculating the rate equation, we provide evidence that TlCl may have similar cooling capabilities to TlF. Our analysis also indicates the potential advantages of boosting stimulated radiation in optical cycles to improve cooling efficiency.
Multifunctionality in ferromagnetic shape memory alloy-based resistive switching memory for flexible ReRAM application
Authors: Kumar Pradeep , Kaur Davinder
Published: July 2022

Multifunctional flexible electronics is the ongoing demand for fabricating wearable data storage and communication devices. The magnetoelectric (ME) heterostructure consisting of piezoelectric (AlN) and ferromagnetic magnetic shape memory alloy [FSMA (Ni–Mn–In)] was fabricated over stainless steel (SS) substrate for resistive random access memory application. The Cu/AlN/FSMA/SS metal–insulator–metal based memory cell displays bipolar resistive switching (RS) behavior. The formation of Cu metallic filament at a particular SET voltage leads the memory cell in a low resistance state (LRS) from its pristine high resistance state (HRS). The LRS and HRS are explained well by Ohmic and space charge limited conduction mechanisms, respectively. The fabricated memory cell displays excellent endurance and data retention capability with a high OFF/ON ratio of ∼1.2 × 103. Furthermore, the multifunctionality of the ME heterostructure-based RAM was investigated by tuning the SET voltage with ambiance temperature and external magnetic field remotely. A significant change in the SET voltage could be ascribed to the temperature and magnetic field-induced strain transferred to the AlN piezoelectric layer from the magnetostrictive FSMA (Ni–Mn–In) bottom electrode. The residual Lorentz force explains the remotely tuned LRS and HRS in the transverse magnetic field for multi-bit data storage applications. Moreover, the RS characteristics remain stable even after 800 bending cycles as well as with bending angle (0°–180°). Hence, the present ME heterostructure integrated with flexible SS substrate can be a better choice for highly flexible, low-cost, and multifunctional futuristic RAM applications.
Detecting hidden transient events in noisy nonlinear time-series
Authors: Montoya A. , Habtour E. , Moreu F.
Published: July 2022

The information impulse function (IIF), running Variance, and local Hölder Exponent are three conceptually different time-series evaluation techniques. These techniques examine time-series for local changes in information content, statistical variation, and point-wise smoothness, respectively. Using simulated data emulating a randomly excited nonlinear dynamical system, this study interrogates the utility of each method to correctly differentiate a transient event from the background while simultaneously locating it in time. Computational experiments are designed and conducted to evaluate the efficacy of each technique by varying pulse size, time location, and noise level in time-series. Our findings reveal that, in most cases, the first instance of a transient event is more easily observed with the information-based approach of IIF than with the Variance and local Hölder Exponent methods. While our study highlights the unique strengths of each technique, the results suggest that very robust and reliable event detection for nonlinear systems producing noisy time-series data can be obtained by incorporating the IIF into the analysis.
Continuously adjusting infrared emissivity of multilayer graphene using pulse voltage
Authors: Li Junxiao , Peng Wenlian , Huang Huang , Ke Haibo , Liu Zhe , Huang Ruoyu , Guo Xiaoxiao , Cheng Shujian , Zhang Yufeng , Dai Mengyan , Zhang Xue-ao
Published: July 2022

Steadily, continuously, and precisely adjusting infrared emissivity of materials is of great importance for various applications, such as thermal camouflage. Herein, a method is proposed to fine-tune the emissivity of multilayer graphene (MLG) by ion intercalation with assistance of pulse voltage. The dynamic ion intercalation process in MLG-based emissivity modulators is investigated by a home-made electrical-optical synchronizing test system, which consists of a potentiostat and a thermal camera. It is observed that the apparent temperature of MLG is closely correlated with pulse duration and residual charges. Based on a second-order RC model, the ion transportation and charge transfer in the modulator are likely affected by three factors (i.e., internal resistance, electric field, and concentration gradient), which changes the doping level of MLG. Hence, the emissivity of MLG can be finely adjusted by regulating the duration of the voltage pulse. This also leads to a wavelength dependence of emissivity modulation, which is confirmed by Fourier transform infrared spectroscopy. The observations offer a promising venue for precise and continuous adjustment of MLG's emissivity, which is of great significance for many practical applications, such as simulating complex and subtle thermal images.
Water surge impingement onto a vertical wall: A new self-similarity solution for impact pressure
Authors: Xie Wenang , Shimozono Takenori
Published: July 2022

The impingement process of water surge onto a vertical wall and the impact pressure are studied analytically in this work. We propose a new initial-boundary value problem particularly for the fluid motion near the corner of the horizontal bed and the vertical wall. The explicit solutions of the velocity and the pressure fields are analytically obtained using the self-similarity method under some verifiable physical assumptions. The impact pressure is found to be proportional to the product of the squared incident surge front velocity and the density of water, with a constant coefficient of around 0.867. We compare the analytical solution of the impact pressure with some existing laboratory data. The analytical solution agrees with the median value of the stochastic data of impact pressure from laboratory experiments. Subsequently, the velocity and the pressure fields from the analytical model are compared to the numerical simulation results based on OpenFOAM. The comparisons validate the physical assumptions made in the analytical derivation, demonstrating fair consistency. The analytical model successfully describes the early stage of the contact process between the surge front and the wall and provides a theoretical basis for the physics of water surge impingement.
Helium droplet infrared spectroscopy of the butyl radicals
Authors: King Kale E. , Franke Peter R. , Pullen Gregory T. , Schaefer Henry F. , Douberly Gary E.
Published: July 2022

Butyl radicals (n-, s-, i-, and tert-butyl) are formed from the pyrolysis of stable precursors (1-pentyl nitrite, 2-methyl-1-butyl nitrite, isopentyl nitrite, and azo-tert-butane, respectively). The radicals are doped into a beam of liquid helium droplets and probed with infrared action spectroscopy from 2700 to 3125 cm−1, allowing for a low temperature measurement of the CH stretching region. The presence of anharmonic resonance polyads in the 2800–3000 cm−1 region complicates its interpretation. To facilitate spectral assignment, the anharmonic resonances are modeled with two model Hamiltonian approaches that explicitly couple CH stretch fundamentals to HCH bend overtones and combinations: a VPT2+K normal mode model based on coupled-cluster with single, double, and perturbative triple excitations [CCSD(T)] quartic force fields and a semi-empirical local mode model. Both of these computational methods provide generally good agreement with the experimental spectra.
Temperature-dependent dynamics at protein–solvent interfaces
Authors: Reuhl Melanie , Vogel Michael
Published: July 2022

We perform differential scanning calorimetry, broadband dielectric spectroscopy (BDS), and nuclear magnetic resonance (NMR) studies to understand the molecular dynamics in mixtures of ethylene glycol with elastin or lysozyme over broad temperature ranges. To focus on the protein–solvent interface, we use mixtures with about equal numbers of amino acids and solvent molecules. The elastin and lysozyme mixtures show similar glass transition steps, which extend over a broad temperature range of 157–185 K. The BDS and NMR studies yield fully consistent results for the fastest process P1, which is caused by the structural relaxation of ethylene glycol between the protein molecules and follows an Arrhenius law with an activation energy of Ea = 0.63 eV. It involves quasi-isotropic reorientation and is very similar in the elastin and lysozyme matrices but different from the α and β relaxations of bulk ethylene glycol. Two slower BDS processes, viz., P2 and P3, have protein-dependent time scales, but they exhibit a similar Arrhenius-like temperature dependence with an activation energy of Ea ∼ 0.81 eV. However, P2 and P3 do not have a clear NMR signature. In particular, the NMR results for the lysozyme mixture reveal that the protein backbone does not show isotropic α-like motion on the P2 and P3 time scales but only restricted β-like reorientation. The different activation energies of the P1 and P2/P3 processes do not support an intimate coupling of protein and ethylene glycol dynamics. The present results are compared with previous findings for mixtures of proteins with water or glycerol, implying qualitatively different dynamical couplings at various protein–solvent interfaces.
Toxicity of arsenic(
Authors: Golding Lisa A. , Valdivia Maria V. , van Dam Joost W. , Batley Graeme E. , Apte Simon C.
Published: July 2022

Environmental context High-quality ecotoxicology data are required to derive reliable water quality guideline values that ensure long-term protection of marine biota from arsenate. Tropical and temperate marine biota have sensitivity to arsenate covering three to four orders of magnitude due to the range of arsenate detoxification mechanisms used to reduce toxicity. The water quality guideline values derived in this study will contribute to robust risk assessments of arsenate in marine environments. Rationale There are very few high-quality chronic inorganic arsenate (AsV) toxicity data to assess the risks to marine ecosystems. We aimed to determine the range in chronic toxicity of AsV to marine biota and derive reliable water quality guideline values (GVs) for the long-term protection of marine ecosystems. Methodology We generated chronic toxicity data based on measured dissolved (<0.45 µm filtered) AsV concentrations for 13 marine species representing seven taxonomic groups from temperate and tropical environments. Effect concentrations at the 10% level (EC10) were used in a species sensitivity distribution (SSD) to derive water quality GVs. Results The range of concentrations causing chronic 10, 20 and 50% adverse effects were 13–26 000, 18–34 000 and 32–330 000 µg AsV L–1, respectively. Increased phosphate and nitrate concentrations were found to reduce the toxicity of AsV to certain microalgal, sea urchin and bivalve species. The range in effect concentrations for tropical versus temperate species overlapped at all effect levels. The GVs for the long-term protection of 80, 90, 95 and 99% of marine biota were: 48, 22, 12 and 4.8 µg AsV L–1, respectively. Discussion Recommendations on performing toxicity tests with arsenic to prevent artefacts associated with arsenic speciation were made to improve future research on arsenic toxicity. The new data will improve the reliability status of the Australian and New Zealand AsV GVs for marine water quality and fill a data gap for global risk assessments of AsV for marine biota.
Vertical distribution of soil aggregates and associated organic carbon fractions under conventional vegetable- and rice-based tillage operations
Authors: Shoumik Baig Abdullah Al , Islam Md. Sanaul
Published: July 2022

Context Vegetable- and rice-based cropping systems are the dominant agricultural practices across South Asia, but the conventional tillage method associated with their cultivation is responsible for soil degradation in terms of aggregates and organic carbon in the surface layer. However, knowledge of its impact on the deeper layers is needed because the aggregate and organic carbon dynamics in deeper soils are little understood. Aims This study analysed the effects of conventional rice-based tillage (RBT) and vegetable-based tillage (VBT) operations on the vertical distribution of aggregates and aggregate-associated organic carbon fractions. Methods Soil samples were collected from 10 vegetable and rice fields, where conventional tillage systems were applied, and analysed for the vertical distribution of aggregates, soil carbon stock, aggregate-associated total organic carbon (AATOC), the relationship between mean weight diameter (MWD) and AATOC, and intra-aggregate particulate organic carbon (iPOC). Key results Soil macroaggregates, MWD, AATOC, and iPOC for the surface soils under RBT were less than for soils under VBT, indicating that soils under RBT had weaker aggregate stability compared to soils under VBT. The relationship between MWD and AATOC was significant (P < 0.01) for the top layers of VBT, but this relationship was non-significant for RBT. Conclusions The study suggests that wet rice cultivation has an adverse effect on soil aggregate stability and its associated organic carbon fractions. Implications Alternative tillage operations for rice-based cultivation are necessary to avoid soil degradation in rice fields.
Natural Evolution Provides Strong Hints about Laboratory Evolution of Designer Enzymes
Authors: Xie Wen Jun , Warshel Arieh
Published: July 2022

Laboratory evolution combined with computational enzyme design provides the opportunity to generate novel biocatalysts. Nevertheless, it has been challenging to understand how laboratory evolution optimizes designer enzymes by introducing seemingly random mutations. A typical enzyme optimized with laboratory evolution is the abiological Kemp eliminase, initially designed by grafting active site residues into a natural protein scaffold. Here, we relate the catalytic power of laboratory-evolved Kemp eliminases to the statistical energy (

E

MaxEnt

) inferred from their natural homologous sequences using the maximum entropy model. The

E

MaxEnt

of designs generated by directed evolution is correlated with enhanced activity and reduced stability, thus displaying a stability-activity trade-off. In contrast, the

E

MaxEnt

for mutants in catalytic-active remote regions (in which remote residues are important for catalysis) is strongly anticorrelated with the activity. These findings provide an insight into the role of protein scaffolds in the adaption to new enzymatic functions. It also indicates that the valley in the

E

MaxEnt

landscape can guide enzyme design for abiological catalysis. Overall, the connection between laboratory and natural evolution contributes to understanding what is optimized in the laboratory and how new enzymatic function emerges in nature, and provides guidance for computational enzyme design.
Translating satire inMafaldaandA Turma da Mônica
Authors: Poteau Christine E.
Published: July 2022

In both the Spanish-language Argentine comic stripMafalda,created by Quino, and the Portuguese-language Brazilian comicA Turma da Mônicaby Maurício de Sousa, the creators’ use of political and cultural satire unveils critical global and national issues through the eyes of young female protagonists. Character naming and effective translation of these comic strips requires an expanded view of satire as a principally literary genre by examining its linguistic and cultural purposes. Thus, this study explores the cultural and linguistic significance of satire in translation along with its associated challenges, drawing on specific examples from these two comic strips to illustrate these issues.
Manipulating Nonsequential Double Ionization of Argon Atoms via Orthogonal Two-Color Field
Authors: Li Yingbin , Qin Lingling , Liu Aihua , Zhang Ke , Tang Qingbin , Zhai Chunyang , Xu Jingkun , Chen Shi , Yu Benhai , Chen Jing
Published: July 2022

Using a three-dimensional classical ensemble model, we investigate the dependence of relative frequency and relative initial phase for nonsequential double ionization (NSDI) of atoms driven by orthogonal two-color (OTC) fields. Our findings reveal that the NSDI probability is clearly dependent on the relative initial phase of OTC fields at different relative frequencies. The inversion analysis results indicate that adjusting the relative frequency of OTC fields helps control returning probability and flight time of the first electron. Furthermore, manipulating the relative frequency at the same relative initial phases can vary the revisit time of the recolliding electron, leading that the emission direction of Ar2+ ions is explicitly dependent on the relative frequency.
Non-Hermitian quantum-like cascaded nonlinear optical frequency conversion and splitting in dissipative media
Authors: Al-Mahmoud Mouhamad , Coda Virginie , Rangelov Andon , Montemezzani Germano
Published: July 2022

It is shown that cascaded nonlinear optical frequency conversion over an intermediate wavelength, subjected to dissipation, behaves similarly to population transfer via a decaying state in a three-state non-Hermitian quantum system. The intermediate dissipation leads to a fixed phase relationship between the input signal wave and the wave at the target frequency, what finally stabilizes both waves preventing any spatial oscillation of their powers. The cascaded conversion acts as a stable wave splitter between the input and target waves, the latter being nearly immune to power fluctuations of the pumps. A case of a simultaneous cascade of the sum frequency generation and the difference frequency generation processes is discussed as an example. A possible implementation, based on aperiodically engineered quasi-phase-matching in lithium niobate, is proposed.
A novel bootstrap ensemble learning convolutional simple recurrent unit method for remaining useful life interval prediction of turbofan engines
Authors: Zhao Chengying , Huang Xianzhen , Liu Huizhen , Gao Tianhong , Shi Jiashun
Published: July 2022

The deep neural network is widely applied in remaining useful life (RUL) prediction because of its strong feature extraction ability. However, the prediction results of deep learning neural networks are often influenced by random noise and modeling parameters. Moreover, the training process of the traditional neural network is time-consuming. To overcome these drawbacks, a novel bootstrap ensemble learning convolutional simple recurrent unit (ELCSRU) method is proposed for RUL prediction. The simple recurrent unit is used to learn the time-series features of sensor data, which can effectively reduce the model parameters and boost the calculation speed. Moreover, the RUL prediction uncertainty can be quantified using the prediction interval, which can be calculated by the ELCSRU model. The prediction performance of the ELCSRU model is demonstrated using a turbofan engine dataset. The experimental results show that the proposed ELCSRU model provides a prognosis framework with better prediction performance for quantifying RUL prediction uncertainty.
Simple model for tokamak outer midplane electron temperature profile in scrape-off-layer verified by SOLPS-ITER simulations
Authors: Poletaeva A , Kaveeva E , Rozhansky V , Veselova I
Published: July 2022

A simple analytical model for the estimation of scrape-off-layer (SOL) electron temperature profile in the equatorial outer midplane (OMP) is suggested. It is demonstrated that the OMP electron temperature profile in the SOL can be approximated by a power function of the radial coordinate for constant anomalous perpendicular transport coefficients. The obtained profile gives a slower radial decrease with respect to exponential fitting, which is widely used for OMP electron temperature estimation in the near-SOL region. It is shown that the analytical profiles are in good agreement with those obtained from SOLPS-ITER simulations for the semi-detached regimes of ITER, JET and ASDEX-Upgrade. They are also in reasonable agreement with experimental Thomson scattering profiles for JET and ASDEX-Upgrade. Analysis based on SOLPS-ITER simulation shows that account of more complicated effects such as energy exchange with ions, convective energy transport, etc, can change quantitatively by factors of the order of unity, but not qualitatively, the radial electron OMP temperature profiles.
Power spectral density-based fractal analyses of sputtered yttria-stabilized zirconia thin films
Authors: Eftekhari Leila , Raoufi Davood , Javad Eshraghi Mohamad , Ghasemi Mohsen
Published: July 2022

This study provides information about the surface morphology of sputtered yttria-stabilized zirconia (YSZ) thin films from the atomic force microscope (AFM) spectral analyses using the power spectral density (PSD) function at varying annealing temperatures. Applying fractal and k-correlation fitting models to the PSD data, fractal dimension, Hurst exponent, correlation length, and equivalent root mean square roughness are quantified. The PSDs of the films exhibit an inverse power-law variation at high spatial frequency, which points to the existence of the fractal components in the film’s surface. The annealing temperatures up to 900 ∘C decreased fractal dimension from 2.60 to 2. The surface roughness increased from 0.10 to 13.92 nm and from 0.04 to 3.95 nm, obtained from the statistical analyses of AFM images and the k-correlation model. The films annealed from 500 ∘C to 800 ∘C showed fine grain size morphology with Hurst exponent values from 0.40 to 0.53, indicating a homogeneous spatial roughness distribution. While the film annealed at 900 ∘C exhibited large aggregate grains morphology. The growth of a sample annealed at the temperature of 900 ∘C is more likely to be ruled by the step-edge barrier-induced mound growth and inhomogeneous spatial distribution of roughness. In contrast, normal self-affine behaviour is observed at lower annealing temperatures.
Effects of γ-irradiation on AC electrical and impedance spectroscopy of Ni-Zn nano ferrites
Authors: Kumar M V Santhosh , Alzahrani Hassan A H , G J Shankaramurthy , K K Nagaraja , Alsaiari Abdulmohsen O , B M Prasanna , N Chandamma
Published: July 2022

Herein we report the effect ofγ-irradiation on the structural and AC electrical properties of Ni-Zn nanoparticlesNi1−xZnxFe2O40≤x≤1synthesised via the citrate auto-combustion technique. The x-ray diffraction (XRD) analysis of the samples revealed a decreasing trend of the crystallite size with increasing concentration of Zn2+ions, and -irradiation alters the crystallite size for more Ni2+ion concentrations. The lattice constant was found to increase with Zn2+concentration, with the highest for x = 0.6. However, after irradiation, substantial change occurs. The lattice strain is greater for x = 1 as well as lower for x = 0.4. The observable modifications in the morphology of the samples upon irradiation are identified. The AC-electrical behaviour of the sample was studied before and afterγ-irradiation in the frequency range of 1 MHz–23 MHz. Studies show that the dielectric constant increases on irradiation, whereas the dielectric loss and AC conductivity decline after irradiation. The dielectric relaxation changes from non-Debye to Havriliak–Negami relaxation, which is the significance of asymmetric broadness in the relaxation process. The collective AC electrical properties were signifies the radiation absorption response.
Multiperiodic and chaotic wave phenomena of collective ion dynamics under KP-type equation in a magnetised nonextensive plasma
Authors: Saha Asit , Pradhan Barsha , Natiq Hayder
Published: July 2022

Dynamical features of small-amplitude ion-acoustic waves are investigated under KP-type equation in a magnetized electron-ion plasma, where electrons follow q-nonextensive distribution. To carry out this investigation, a four dimensional conservative dynamical system is proposed from this plasma model. By changing values of travelling wave velocity, ratio between ion gyro frequency and ion plasma frequency and q-nonextensive parameter, the system produces different dynamical features, such as periodic, multi-periodic, quasiperiodic, and chaotic ion-acoustic wave phenomena. It is observed that ratio between ion gyro frequency and ion plasma frequency plays the key role in the existence of ion-acoustic chaotic wave phenomenon. Also, existence of higher order periodic trajectories is seen to indicate chaotic phenomenon.
Direction decoding of imagined hand movements using subject-specific features from parietal EEG
Authors: Sagila Gangadharan K , Vinod A P
Published: July 2022

Objective. Research on the decoding of brain signals to control external devices is rapidly emerging due to its versatile potential applications, including neuroprosthetic control and neurorehabilitation. Electroencephalogram (EEG)-based non-invasive brain–computer interface (BCI) systems decode brain signals to establish an augmented communication and control pathway between the brain and the computer. The development of an efficient BCI system requires accurate decoding of neural activity underlying the user’s intentions. This study investigates the directional tuning of EEG characteristics from the posterior parietal region, associated with bidirectional hand movement imagination or motor imagery (MI) in left and right directions. Approach. The imagined movement directions of the chosen hand were decoded using a combination of envelope and phase features derived from parietal EEGs of both hemispheres. The proposed algorithm uses wavelets for spectral decomposition, and discriminative subject-specific subband levels are identified based on Fisher analysis of envelope and phase features. The selected features from the discriminative subband levels are used to classify left and right MI directions of the hand using a support vector machine classifier. Furthermore, the performance of the proposed algorithm is evaluated by incorporating a maximum-variance-based EEG time bin selection algorithm. Main results. With the time bin selection approach using subject-specific features, the proposed algorithm yielded an average left vs right MI direction decoding accuracy of 73.33% across 15 healthy subjects. In addition, the decoding accuracy offered by the phase features was higher than that of the envelope features, indicating the importance of phase features in MI kinematics decoding. Significance. The results reveal the significance of the parietal EEG in decoding of imagined kinematics and open new possibilities for future BCI research.
Silicon nanoparticles as active materials for LED: laser synthesis and functionalization for tuning luminescence
Authors: D’Amato R. , Iacono S. Dello , Santoni A. , Reale P. , Limosani F. , Terranova G. , Botti S. , Bonfigli F. , Migliori A. , Scalbi S.
Published: July 2022

Silicon nanocrystals (SiNPs) are an extensively studied light-emitting material due to their inherent biocompatibility and easy integration with silicon-based technology. Although low luminescence quantum yields of as-prepared SiNPs, the exploitation of the surface chemistry of SiNPs plays a key role in tuning their luminescence. In this work, the development of SiNPs as active materials for innovative LEDs was investigated. SiNPs were synthesized by using laser pyrolysis, a very flexible tool for lab-scale production in developmental quantities. The synthesized SiNPs have dimensions from 5 to 15 nm and high purity grade but show weak luminescence. For this reason, chemical treatments were performed on SiNPs: surface modifications lead to an improvement of their luminescence properties. Chemical and optical characterization were performed by conventional and advanced techniques, such as FTIR, BET, UV-VIS absorption and emission, XPS, TEM and confocal Raman. A Life Cycle Assessment (LCA) study of laser synthesis of SiNPs was conducted with the aim to identify the potential environmental impacts coming from this production method.
Hybrid materials based on inorganic aerogel and organic luminophore
Authors: Lebedev A , Suslova E , Kazmina K , Khomyakov A , Zykova M , Petrova O , Avetisov R , Menshutina N , Avetissov I
Published: July 2022

A new luminescent hybrid material based on inorganic aerogel “LightSil” (hereinafter referred to as HM-LS) has been fabricated. Organic phosphor has been directly synthesized from boron and 8-hydroxyquinolinol within the aerogel porous structure during its supercritical drying. Intercalation of various amounts of boron ions (0.01, 0.05 and 0.1 wt%) proceed at the gel aging stage. Synthesis and supercritical drying of materials were conducted in high pressure apparatus in a supercritical carbon dioxide medium at 120 bar pressure, 40°C and 500 g/h gas flow rate. The influence of ion amount on the luminescent, physical and structural characteristics of HM-LS were investigated. Analysis of the PL spectra showed that HM-LS with a boron ion concentration of 0.05 wt% has a highest photoluminescence intensity at a wavelength of 513 nm.
Influences of Raw Powder on Transparent Al2O3 Prepared by Two-Step Pulsed Electric Current Sintering
Authors: Ogashiwa Y , Suzuki Y , Tanaka K , Okumoto Y , Kuo Y-L. , Nanko M
Published: July 2022

In order to fabricate Al2O3 ceramics with high transparency, six types of commercial α-Al2O3 powders were consolidated with a two-step pulsed electric current sintering (PECS) in this study. High density in Al2O3 usually has a positive effect on its transmittance, while as some α-Al2O3 powders show low transparency with almost full-densification. It suggested that abnormal grain growth may affect transparency of Al2O3 ceramics. Since pressure sintering in Al2O3 is influenced with dynamic grain phenomena, the differences in abnormal grain growth must be influenced with difference in properties of Al2O3 powder such as crystallinity.
Semiconductor Metal Oxides Doped with Gold Nanoparticles for Use in Acetone Gas Sensors
Authors: Ovodok E. , Kormosh V. , Bilanych V. , Ivanovskaya M.
Published: July 2022

The effect of nanosized gold particles on the adsorption-sensitive properties of SnO2–Au sensors under the detection of acetone vapors has been studied. Different techniques for the preparation of SnO2–Au nanocomposites with an average Au particle size of 2 nm were applied. It has been found that a fivefold increase in the sensor response to acetone vapors and threshold sensitivity (C
lim) of 0.1 ppm are achieved by adding gold to tin dioxide in the colloidal form during synthesis. While adding gold in ion form (Au (III)) leads to a growth of the sensor response to acetone vapors by 2.7 times and defines C
lim of 0.2 ppm. The slope of the calibration curves of the SnO2–Au sensors allows registering acetone vapors at concentrations ranging from C
lim to 5 ppm. This concentration range can be used for express diagnostics in diabetes. The enhanced sensitivity of SnO2–Au sensors to acetone vapors can be explained by an increase in the adsorption-catalytic activity of tin ions as a result of the modifying effect of sulfate groups and the envolving of highly dispersed gold in the adsorption – catalytic process of oxidation of acetone molecules.
Hydrogen Embrittlement and its Effect on Fatigue Life of Nitrided Steel in Gigacycle Fatigue: Analysis and Modelling
Authors: Major Š
Published: July 2022

This paper deals with the effect of hydrogen embrittlement on the fatigue life of steels. This phenomenon is typical for the gigacycle fatigue region, but we also encounter it in surface-treated materials. in which a subsurface crack initiation has occurred. In samples in which the fracture is affected by the presence of hydrogen embrittlement, subsurface fatigue crack initiation occurs. In this work we observe the change in toughness and local elastic modulus depending on the hydrogen diffusion of hydrogen over time.
Radioactive Waste Embedding in Cement Matrix and the Establishment of Cemented Waste Testing Laboratory at Paks Nuclear Power Plant
Authors: Baranyi Attila , Kopecskó Katalin
Published: July 2022

For the treatment of low and intermediate level radioactive wastes generated at the Nuclear Power Plant of Paks, a new compact waste package will be created with a new cementation technology currently under construction. During the operation, the solid waste will be placed in steel drums, which then will be put into a thin-walled steel container. The cavity volume of the containers will be filled with cemented slurry made using liquid radioactive waste. The compact waste packages must comply with the waste acceptance criteria described in the National Radioactive Waste Repository Safety Report. The task of the cemented waste testing laboratory, which is under construction, will be the in-service inspection of the finished cemented material and the determination of properties such as compressive strength and leachability (diffusion coefficient) of the specimens made thereof. During the installation of the laboratory and testing of the devices used in the cement / concrete industry, it turned out that in many cases special moulds are required due to the low viscosity and corrosive properties of the radioactive paste. In addition, the collection of debris generated during the measurement of compressive strength of radioactive cement stone and the minimization of dusting are important requirements.
The Sterophotogrammetrical reconstruction of crack topography in Cr-Al-Mo nitrided steel and determination of condition at the crack front of sub-surface iniateted crack
Authors: Major Š , Hubálovská M
Published: July 2022

This article deals with problem of determination of condition at the crack front of specimens with nitrided surface layer. The determination of the conditions at the crack front is realized using the HRR theory of the stress field. The COD obtained by fractographic analysis were used as input values for the calculations This method for determining the conditions was applied to samples with fatigue crack, loaded by the Push-pull mode and further by torsion, bending and their combination. The fractographic analysis used 3D reconstruction of the fracture surface realized by stereophotogrammetry. In order to verify the effectiveness and applicability of the method, measurements performed on samples without a surface layer were also included in the analysis. Experimental work has shown that the described method can determine the conditions at the crack front, however, the method is much more suitable for samples without a surface layer than for nitrided samples. This is probably due to the fact that it is easier to measure COD values in this case.
Microstructural characterization of cement-bound materials influenced by the inclusion of Graphene Oxide (GO) – state of the art
Authors: Kopecskó Katalin , Abdulhussein Khaiqani Zaid Ali
Published: July 2022

In the last few years, the integration of graphene oxide (GO) into the cementitious matrix has evolved as one of the most well-known inclusion of nanomaterials. The paper addresses the advancement of GO research including the microstructure modifications of GO-modified cement-based materials. The effects of GO were evaluated based on the results of the related researches using different microstructural test methods. The use of GO in scientific disciplines like construction materials technology has made substantial progress. It demonstrates promising outcomes of using GO to develop innovative construction materials. However, further research is needed for future developments.
Influence of layers orientation of graphene stacks in shungite disordered carbon to its integral electrical conductivity
Authors: Antonets I V , Golubev Ye A , Ignatiev G V , Shcheglov V I , Gömze László A. , Sun Shiyong
Published: July 2022

The map of carbon distribution in the sample of graphene-containing shungite is investigated by the electron microscopy. It is found the large quantity of stacks which are formatted by parallel disposed layers of graphene. The model of electrical conductivity of graphene stack is proposed. This model takes into consideration the arbitrary orientation of layers relatively to the direction of current. It is made the numerical calculation of dependence of conductivity from the orientation of graphene layers. It is found the sharp abatement of conductivity by the orientation of graphene layers relatively to the current direction along the corner near the 45 degree. The obtained peculiarities are explained by the influence of geometrical factor.
The half-period addition formulae for genus two hyperelliptic ℘ functions and the Sp(4,

R

) Lie group structure
Authors: Hayashi Masahito , Shigemoto Kazuyasu , Tsukioka Takuya
Published: July 2022

In the previous study, by using the two-flows Kowalevski top, we have demonstrated that the genus two hyperelliptic functions provide the Sp(4,

R

)/

Z

2

≅ SO(3, 2) Lie algebra structure. In this study, by directly using the differential equations of the genus two hyperelliptic ℘ functions instead of using integrable models, we demonstrate that the half-period addition formula for the genus two hyperelliptic functions provides the order two Sp(4,

R

) Lie group structure.
Measuring outdoor I–V characteristics of PV modules and systems
Authors: Augusto André , Killam Alexander , Bowden Stuart G , Wilterdink Harrison
Published: July 2022

The cumulative installed capacity of photovoltaics has passed 1 TW, of which about two-thirds were only installed in the past five years. Many of these new installations incorporate novel module and cell designs that have not yet been subjected to long-term in-field characterization. Indoor accelerated stress testing has historically been a valuable methodology to identify fault mechanisms, estimate degradation rates, and to ensure the safety and normal operation of modules in the field. Still, these methodologies deliver an incomplete image of the exact stress mechanisms that photovoltaic systems are subject to outdoors, which vary with location, time of day, and time of year. In this work we review different outdoor methods to measure current–voltage (I–V) characteristics of photovoltaic systems, discuss how the environmental conditions impact those characteristics, and examine alternative methodologies for acquiring light and pseudo I–V characteristics more applicable to larger scale installations. This review also provides an insight into methods useful for real-time monitoring and degradation analysis at the module and string level.
PVC gel smart sensor for robotics sensing applications: an experimental and finite element simulation study
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Authors: Sharif Montassar Aidi
Published: July 2022

Research is now being done on soft electroactive polymers (EAPs), such as polyvinyl chloride (PVC) gel, as an example, for use in soft robotics and smart sensors. Although the sensing behavior of PVC gel has not yet been thoroughly investigated, it has been determined that this material reacts in some way to the stimuli that come from the outside. PVC gels are being utilized to construct a broad variety of different kinds of smart sensors due to the fact that their deformation may be endlessly configured by variations in electrode arrangement, applied mechanical stress, and the amount of plasticizer contained within the gel. In this study, experimental characterizations and the results of finite element simulations are discussed for a PVC gel compression sensor. The finite element simulation of what happens to PVC gel when it is compressed from the outside using mechanical force has been built using the COMSOL Multiphysics, which is a finite element simulation software. Additional experimental measurements of PVC gels are carried out in order to validate the underlying principles that have been presented thus far by providing context for the results of the simulations and to validate the findings effectively. Based on the findings, it appears that the suggested sensor is able to detect compression at a variety of amplitudes and rates . This study sheds light on the sensing capabilities of PVC gel in sensing investigations and provides a framework for conducting such investigations, thereby laying the groundwork for an increase in the use of PVC gel sensors in soft robotics research in the future.
Advances in bismuth-based topological quantum materials by scanning tunneling microscopy
Authors: Li Yaqi , Zhang Jingwei , Xu Xun , Hao Weichang , Zhuang Jincheng , Du Yi
Published: July 2022

In recent years, topological quantum materials (TQMs) have attracted intensive attention in the area of condensed matter physics due to their novel topologies and their promising applications in quantum computing, spin electronics and next-generation integrated circuits. Scanning tunneling microscopy/spectroscopy (STM/STS) is regarded as a powerful technique to characterize the local density of states with atomic resolution, which is ideally suited to the measurement of the bulk-boundary correspondence of TQMs. In this review, using STM/STS, we focus on recent research on bismuth-based TQMs, including quantum-spin Hall insulators, 3D weak topological insulators (TIs), high-order TIs, topological Dirac semi-metals and dual TIs. Efficient methods for the modulation of the topological properties of the TQMs are introduced, such as interlayer interaction, thickness variation and local electric field perturbation. Finally, the challenges and prospects for this field of study are discussed.