bluuebunny/crossref_metadata_2025 huggingface dataset:
Natural Language Processing to Extract Meaningful Information from Patient Experience Feedback
Authors: Nawab Khalid , Ramsey Gretchen , Schreiber Richard
Published: April 2020

Background Due to reimbursement tied in part to patients' perception of their care, hospitals continue to stress obtaining patient feedback and understanding it to plan interventions to improve patients' experience. We demonstrate the use of natural language processing (NLP) to extract meaningful information from patient feedback obtained through Press Ganey surveys.

Methods The first step was to standardize textual data programmatically using NLP libraries. This included correcting spelling mistakes, converting text to lowercase, and removing words that most likely did not carry useful information. Next, we converted numeric data pertaining to each category based on sentiment and care aspect into charts. We selected care aspect categories where there were more negative comments for more in-depth study. Using NLP, we made tables of most frequently appearing words, adjectives, and bigrams. Comments with frequent words/combinations underwent further study manually to understand factors contributing to negative patient feedback. We then used the positive and negative comments as the training dataset for a neural network to perform sentiment analysis on sentences obtained by splitting mixed reviews.

Results We found that most of the comments were about doctors and nurses, confirming the important role patients ascribed to these two in patient care. “Room,” “discharge” and “tests and treatments” were the three categories that had more negative than positive comments. We then tabulated commonly appearing words, adjectives, and two-word combinations. We found that climate control, housekeeping and noise levels in the room, time delays in discharge paperwork, conflicting information about discharge plan, frequent blood draws, and needle sticks were major contributors to negative patient feedback. None of this information was available from numeric data alone.

Conclusion NLP is an effective tool to gain insight from raw textual patient feedback to extract meaningful information, making it a powerful tool in processing large amounts of patient feedback efficiently.
Avoiding Above-the-Knee Amputation with a Free Tibiofibular–Talocalcaneal Fillet Flap and Free Latissimus Dorsi Flap
Authors: Garcia-Vilariño Elena , Perez-Garcia Alberto , Salmeron-Gonzalez Enrique , Sanchez-Garcia Alberto , Bas Jose Luis , Simon-Sanz Eduardo
Published: April 2020

Despite the advances achieved in reconstructive surgery, amputation is still the only option after some severe traumas. Preservation of the knee joint is considered a significant functional advantage. We present the case of a 39-year-old man with a comminuted Gustilo type IIIC open tibia fracture with massive bone loss. To achieve a well-fashioned amputation stump and preserve the knee joint, a free osteocutaneous fillet flap was performed, including the distal tibia and fibula, talus, and calcaneus bones. As a result, a sensate and long amputation stump covered with thick skin from the sole of the foot provided a stable coverage with an excellent functional result and adjustment to prosthesis.
Evaluation of the reanalysis surface solar radiation from NCEP, ECMWF, NASA, and JMA using surface observations for Balochistan, Pakistan
Authors: Tahir Zia ul Rehman , Azhar Muhammad , Mumtaz Manhal , Asim Muhammad , Moeenuddin Ghulam , Sharif Hanzalah , Hassan Sohaib
Published: April 2020

Solar radiation from reanalysis datasets can be used to estimate solar energy potential in the absence of long-term surface measured data. Comprehensive validation of reanalysis data against short-term measurements of solar radiation is necessary to find uncertainties. The evaluation of the performance of seven reanalysis datasets (ERA-5, MERRA-2, ERA-Interim, JRA-55, NCEP-NCAR, NCEP-DOE, and CFSR) for Balochistan against high-quality surface measured data was performed using statistical analysis. The relative mean bias error (rMBE), relative mean absolute error (rMAE), and relative root mean square error of reanalysis solar radiation range from −4 to 7%, 8 to 14%, and 16 to 21%, respectively, using sub-daily data of six datasets except for NCEP-NCAR. Seasonal statistical analysis was performed to study seasonal variation of performance of datasets, which reveals the significant variation of errors in different seasons. Analysis of monthly mean data shows that rMBE and rMAE are less than 3 and 5% for ERA-5, respectively. The performance of the dataset changes by changing the temporal resolution of the data used for comparison. The monthly mean values of data show better performance, but the accuracy of data is compromised. The solar radiation data of ERA-5 can be used for preliminary solar resource assessment and power estimation.
Increasing the speed of frequency-domain, homodyne thermoreflectance imaging
Authors: Allison Kyle , Hallman Mark , Koskelo EliseAnne , Hardin Johanna , Radunskaya Ami , Hudgings Janice
Published: April 2020

Charge coupled device (CCD)-based thermoreflectance imaging using a “4-bucket” lock-in imaging algorithm is a well-established, powerful method for obtaining high spatial and thermal resolution two-dimensional thermal maps of optoelectronic, electronic, and micro-electro-mechanical systems devices. However, the technique is relatively slow, limiting broad commercial adoption. In this work, we examine the underlying limit on the image acquisition speed using the conventional “4-bucket” algorithm and show that the straightforward extension to an n-bucket technique by faster sampling does not address the underlying statistical bias in the data analysis and hence does not reduce the image acquisition time. Instead, we develop a modified “enhanced n-bucket” algorithm that halves the image acquisition time for every doubling of the number of buckets. We derive detailed statistical models of the algorithms and confirm both the models and the resulting speed enhancement experimentally, resulting in a practical means of significantly enhancing the speed and utility of CCD-based frequency domain, homodyne thermoreflectance imaging.
The energy-resolved neutron imaging system, RADEN
Authors: Shinohara Takenao , Kai Tetsuya , Oikawa Kenichi , Nakatani Takeshi , Segawa Mariko , Hiroi Kosuke , Su Yuhua , Ooi Motoki , Harada Masahide , Iikura Hiroshi , Hayashida Hirotoshi , Parker Joseph D. , Matsumoto Yoshihiro , Kamiyama Takashi , Sato Hirotaka , Kiyanagi Yoshiaki
Published: April 2020

The energy-resolved neutron imaging system, RADEN, has been installed at the pulsed neutron source in the Materials and Life Science Experimental Facility of the Japan Proton Accelerator Research Complex. In addition to conventional neutron radiography and tomography, RADEN, the world’s first imaging beam-line at a pulsed neutron source, provides three main options for new, quantitative neutron imaging techniques: Bragg-edge imaging to visualize the spatial distribution of crystallographic information, resonance absorption imaging for elemental composition and temperature information, and polarized neutron imaging for magnetic field information. This paper describes the results of characterization studies of the neutronic performance and installed devices at RADEN and shows the results of several demonstration studies for pulsed neutron imaging.
Ultrasonic signal denoising based on autoencoder
Authors: Gao Fei , Li Bing , Chen Lei , Wei Xiang , Shang Zhongyu , He Chen
Published: April 2020

At present, denoising parameters in different signal processing algorithms require a specific signal waveform to be set. Human factors would significantly affect the denoising result. To solve this problem, we proposed a signal adaptive denoising method based on a denoising autoencoder to achieve denoising on ultrasonic signals. By applying this method to sample signals and comparing with the singular value decomposition (SVD), principal component analysis (PCA), and wavelet algorithms, it is found that this method can effectively suppress the noise at different noise intensities. Using the signal to noise ratio, root mean square error, and autocorrelation coefficient as evaluation parameters in the experiment, the overall denoising effect of the proposed method is better than that of PCA, and this method is better than the wavelet and SVD algorithms having a relatively weak noise intensity. In addition, by comparing the reconstructed signal curve of the proposed method and that of the wavelet algorithm, the proposed method can retain the information of signal saltation with a better performance. Finally, we apply this method for processing ultrasonic signals and verify its effectiveness from time and frequency domain diagrams.
Label-free photoacoustic and ultrasound imaging for murine atherosclerosis characterization
Authors: Sangha Gurneet S. , Goergen Craig J.
Published: April 2020

Dual-modality photoacoustic tomography (PAT) and 4D ultrasound (4DUS) imaging have shown promise for cardiovascular applications, but their use in murine atherosclerosis imaging is limited. This study used PAT and 4DUS to correlate altered arterial strain and hemodynamics to morphological changes and lipid localization in a murine partial carotid ligation (PCL) model of atherosclerosis. Validation experiments showed a positive correlation between the PAT signal-to-noise ratio and plaque lipid composition obtained from oil-red O histology. Cross-sectional in situ PAT and longitudinal in vivo ultrasound imaging was performed using a 40 MHz transducer. Ultrasound timepoints included days 0, 1, 4, 7, 10, and 14 for hemodynamic and strain assessment, and 1100 nm and 1210 nm PAT was implemented at the study end point for hemoglobin and lipid characterization. These study groups were then separated into day 4 post-PCL with (n = 5) and without (n = 6) Western diet feeding, as well as days 7 (n = 8), 10 (n = 8), and 14 (n = 8) post-PCL, in addition to a sham control group on a Western diet (n = 5). Overall, our data revealed a substantial decrease in left carotid artery pulsatility by day 7. The hemodynamic results suggested greater disturbed flow in the caudal regions resulting in earlier vessel stenosis and greater lipid deposition than cranial regions. Morphological and compositional data revealed heterogeneous vascular remodeling between days 0 and 7, with a rapid decrease in the vessel volume/length and the presence of both intraplaque hematoma and lipid deposition at day 10 post-PCL. These results highlight the utility of utilizing dual-modality PAT and 4DUS to study atherosclerosis progression.
The microwave spectrum of 2-methylthiazole: 14N nuclear quadrupole coupling and methyl internal rotation
Authors: Nguyen Thuy , Van Vinh , Gutlé Claudine , Stahl Wolfgang , Schwell Martin , Kleiner Isabelle , Nguyen Ha Vinh Lam
Published: April 2020

The rotational spectrum of 2-methylthiazole was recorded using two pulsed molecular jet Fourier transform microwave spectrometers operating in the frequency range of 2–40 GHz. Due to the internal rotation of the methyl group, all rotational transitions were split into A and E symmetry species lines, which were analyzed using the programs XIAM and BELGI-Cs-hyperfine, yielding a methyl torsional barrier of 34.796 75(18) cm−1. This value was compared with that found in other monomethyl substituted aromatic five-membered rings. The 14N quadrupole coupling constants were accurately determined to be χaa = 0.5166(20) MHz, χbb − χcc = −5.2968(50) MHz, and χab = −2.297(10) MHz by fitting 531 hyperfine components. The experimental results were supplemented by quantum chemical calculations.
Viscous fluid flow inside an oscillating cylinder and its extension to Stokes’ second problem
Authors: Song Yixuan , Rau Matthew J.
Published: April 2020

We present the analytical solution for the fluid motion inside a cylindrical tank whose angular velocity starts from rest and undergoes a harmonic oscillation. This problem, which has not yet been reported, is an extension to Stokes’ second problem where the fluid motion is governed by an outer moving cylindrical boundary and a zero velocity condition at the cylinder center. Different from the flow on the outside of a cylinder, the cylinder radius has a large influence on the internal fluid motion. We show that the fluid approaches solid body rotation for cylinders with outer radii similar to the characteristic viscous length scale of the flow, whereas the motion approaches that of Stokes’ original flat plate solution within very large cylinders. We detail both the transient starting condition and the quasi-steady fluid motion, which we present along with a particle image velocimetry experiment for validation. After decay of the initial startup transient, both quasi-steady analytical and experimental results predict that the oscillatory flow inside has an amplitude of velocity that decreases toward the center of the cylinder. The thickness of the Stokes layer, which is proportional to the penetration depth of the viscous wave, is altered by the size of the cylinder and/or the frequency of oscillation. We show that the penetration depth of the Stokes layer reaches its maximum thickness at intermediate cylinder sizes. The solution and results presented herein are potentially of value to describe the fluid motion in many applications where fluids are contained within cylindrical geometries.
Splittings of d8 configurations of late-transition metals with EOM-DIP-CCSD and FSCCSD methods
Authors: Zhao Hewang , Wang Zhifan , Guo Minggang , Wang Fan
Published: April 2020

Multireference methods are usually required for transition metal systems due to the partially filled d electrons. In this work, the single-reference equation-of-motion coupled-cluster method at the singles and doubles level for double ionization potentials (EOM-DIP-CCSD) is employed to calculate energies of states from the d8 configuration of late-transition metal atoms starting from a closed-shell reference. Its results are compared with those from the multireference Fock-space coupled-cluster method at the CCSD level (FSCCSD) for DIP from the same closed-shell reference. Both scalar-relativistic effects and spin–orbit coupling are considered in these calculations. Compared with all-electron FSCCSD results with four-component Dirac–Coulomb Hamiltonian, FSCCSD with relativistic effective core potentials can provide reasonable results, except for atoms with unstable reference. Excitation energies for states in the (n − 1)d8ns2 configuration are overestimated pronouncedly with these two methods, and this overestimation is more severe than those in the (n − 1)d9ns1 configuration. Error of EOM-CCSD on these excitation energies is generally larger than that of FSCCSD. On the other hand, relative energies of most of the states in the d8 configuration with respect to the lowest state in the same configuration are predicted reliably with EOM-DIP-CCSD, except for the 3P0 state of Hg2+ and states in Ir+. FSCCSD can provide reasonable relative energies for the several lowest states, while its error tends to be larger for higher states.
Prediction of reduced critical electric field strength of hot dry air in the temperature range 300–5000 K at 0.1 MPa for medium-voltage switchgear
Authors: Jang Hyun-Jae , Oh Yeon-Ho , Song Ki-Dong , Kim Young-Il
Published: April 2020

The dielectric breakdown properties of dry air, which is widely used as the insulation gas in switchgears of electric distribution systems, are determined for dry-air switchgear analysis and design. In this study, a two-term Boltzmann analysis was applied to investigate the dielectric breakdown properties of dry air with increasing temperatures (300–5000 K) at atmospheric pressure (0.1 MPa). According to the changes in the component ratios of dry air, the collision cross sections of high-mole-fraction decomposition species were considered. In order to analyze the contribution of each dry-air decomposition species to dielectric properties, we compared the dielectric properties calculated with and without considering small amounts of the species, such as Ar and CO2, in actual dry air. The results show that reliable calculations can be obtained for dry air at atmospheric pressure and temperatures up to 5000 K only by considering species with mole fractions exceeding 10−2 in the composition. Based on the calculations, it is observed that the reduced critical dielectric strength of dry air does not significantly change for temperatures up to 2000 K. This means that the dielectric properties of dry air show temperature independence over a wider temperature range than those of SF6.
Theory of edge localized mode suppression by static resonant magnetic perturbations in the DIII-D tokamak
Authors: Fitzpatrick Richard
Published: April 2020

According to a recent paper [Hu et al., Phys. Plasmas 26, 120702 (2019)], mode penetration at the top of the pedestal is a necessary and sufficient condition for the suppression of edge localized modes (ELMs) by a resonant magnetic perturbation (RMPs) in an H-mode tokamak discharge. This paper employs asymptotic matching theory to model a particular DIII-D discharge in which ELMs were suppressed by an externally generated, static, n = 2, RMP whose amplitude was modulated at a frequency of 1 Hz. It is demonstrated that the response of the plasma to the applied RMP, in the immediate vicinities of the rational (i.e., resonant) surfaces, is governed by nonlinear, rather than by linear, physics. This is the case because the magnetic island widths associated with driven reconnection exceed the linear layer widths, even in cases where driven reconnection is strongly suppressed by plasma rotation. The natural frequency at a given rational surface (i.e., the helical frequency at which the locally resonant component of the RMP would need to propagate in order to maximize driven reconnection) is found to be offset from the local E×B frame in the ion diamagnetic direction. The size of the offset is mostly determined by neoclassical poloidal rotation. Finally, the predictions of a fully nonlinear plasma response model are found to be broadly consistent with the DIII-D experimental data.
Legendre-spectral Dyson equation solver with super-exponential convergence
Authors: Dong Xinyang , Zgid Dominika , Gull Emanuel , Strand Hugo U. R.
Published: April 2020

Quantum many-body systems in thermal equilibrium can be described by the imaginary time Green’s function formalism. However, the treatment of large molecular or solid ab initio problems with a fully realistic Hamiltonian in large basis sets is hampered by the storage of the Green’s function and the precision of the solution of the Dyson equation. We present a Legendre-spectral algorithm for solving the Dyson equation that addresses both of these issues. By formulating the algorithm in Legendre coefficient space, our method inherits the known faster-than-exponential convergence of the Green’s function’s Legendre series expansion. In this basis, the fast recursive method for Legendre polynomial convolution enables us to develop a Dyson equation solver with quadratic scaling. We present benchmarks of the algorithm by computing the dissociation energy of the helium dimer He2 within dressed second-order perturbation theory. For this system, the application of the Legendre spectral algorithm allows us to achieve an energy accuracy of 10−9Eh with only a few hundred expansion coefficients.
Influence of Mn2+ substitution on structural, morphological, electrical, and magnetic properties of Ba0.4Ca0.4Sr0.2MnxTi1−xO3 perovskites
Authors: Anwar Armin , Akter Ayesha , Khan M. N. I.
Published: April 2020

In this research, we have explored the structural, morphological, electrical, and magnetic properties of Mn2+ substituted polycrystalline Ba0.4Ca0.4Sr0.2MnxTi1−xO3 (where x = 0.0, 0.05, 0.10, 0.15, and 0.20) ceramic samples prepared by the standard solid-state reaction system. The x-ray diffraction pattern of the 20% Mn-doped BCSMTO sample has confirmed a cubic to tetragonal structural phase transition. The lattice parameter is found to increase at 15% and 20% Mn concentrations, which is caused due to the inequality in ionic radii of cations. Scanning electron microscope analysis exhibited that, with the increase in Mn contents (x = 0.0–0.15), the average grain size of the samples gets bigger but then significantly decreased at 20% Mn substitution. Dielectric constants for all the samples are higher for lower frequency regions and remain independent at a higher frequency domain. The initial permeability remains almost constant at lower frequencies and then sharply falls at the cut-off frequency, which is in agreement with the Globus model. Among all the studied samples, the 10% Mn-doped ceramic sample shows the highest relative quality factor with significantly demolished loss (tan δM). At room temperature, the M–H loop for the 10% Mn-doped sample demonstrates a domination of diamagnetic nature at a higher magnetic field. The decrement in saturation magnetization with Mn addition suggests that the double-exchange interactions in tetragonal BaTiO3 may have been weakened. The outcome of this analysis emphasizes the impact of Mn as a doping element with 10% concentration in Ba0.4Ca0.4Sr0.2MnxTi1−xO3 that provides enhanced structural and electrical properties, which are associated with homogeneous grain size, reduced porosity, and lower tangent loss.
Anomalous elastic moduli and internal frictions in unpoled and poled lead titanate zirconate ceramics near the Curie temperature
Authors: Xie Mingyu , Li Faxin
Published: April 2020

Phase transitions in ferroelectric materials are always accompanied by mechanical property variations; thus, besides the dielectric measurement, the measurement of mechanical properties can also be used to study the phase transition process in ferroelectrics. In this work, the temperature-dependent Young’s modulus, shear modulus, and the related internal frictions of unpoled and poled lead titanate zirconate (PZT) ceramics (including soft PZT-5H and hard PZT-4) were comparatively measured at tens of kilohertz by using a modified piezoelectric ultrasonic composite oscillator technique (M-PUCOT). It is found that for the unpoled and poled PZT ceramics at Curie temperature (190 °C for PZT-5H and 330 °C for PZT-4), both moduli reach their local minima and both internal frictions exhibit peaks. Below the Curie temperature, the Young’s modulus of the poled PZT is larger than that of the unpoled one, while the tendency of the shear modulus is just the opposite. Above the Curie temperature, both moduli increase quickly and both internal frictions drop quickly, and all the four mechanical parameters of poled PZT coincide with those of the unpoled PZT; they stabilize at about 400 °C for PZT-5H and at about 480 °C for PZT-4. In addition, it is found from the mechanical measurement that poled PZT-5H can be partially depolarized even at 180 °C, slightly below the Curie temperature of 190 °C. The results in this work are very helpful to deeply understand ferroelectric phase transitions, and the M-PUCOT is strongly suggested to measure the temperature-dependent mechanical properties of ferroelectrics.
Astroviruses as causative agents of gastroenteritis
Authors: Palombo Enzo
Published: April 2020

Astroviruses were first identified over 30 years ago and the virus was soon established as an important cause of gastroenteritis, particularly in young children. Human astrovirus disease was thought to result from infection by a limited number of serotypes. However, recent studies have indicated that the extent of genetic diversity is greater than previously assumed. In addition, the widespread occurrence among animals and reports of recombination and possible cross-species transmission suggest that astroviruses have zoonotic potential.
The guessing from context test
Authors: Sasao Yosuke , Webb Stuart
Published: April 2020

This study aims to develop two equivalent forms of the Guessing from Context Test (GCT) and provide its preliminary validity evidence. The GCT is a diagnostic test of the guessing skill and measures the following three important steps in guessing: identifying the part of speech of an unknown word, finding its discourse clue, and deriving its meaning. The test was administered to 428 Japanese learners of English. The results indicate that the two forms each with 20 question sets are equivalent in terms of item difficulty distribution and representativeness of the construct being measured. A wide range of validity evidence was provided using Messick’s validation framework, the Rasch model, qualitative investigations into the relationships to actual guessing, and proposals for score interpretation.
Examining incidental vocabulary acquisition from captioned video
Authors: Jelani Nurul Aini Mohd , Boers Frank
Published: April 2020

Previous comparisons of vocabulary uptake from captioned and uncaptioned audio-visual materials have almost consistently furnished evidence in favour of captioned materials. However, it is possible that many such comparative studies gave an advantage to the captioned input conditions by virtue of their use of written word prompts in the tests. The present study therefore examines whether aurally presented test prompts yield equally compelling evidence for the superiority of captioned over uncaptioned video. Intermediate EFL learners watched a ten-minute TED Talks video either with or without captions and were subsequently given a word recognition and a word meaning test, with half of the test prompts presented in print and the other half presented aurally. While the results of the word recognition test were inconclusive, the word meaning test yielded significantly better scores by the group that watched the captioned video. However, this was due entirely to their superior scores on the printed word prompts, not the aural ones. This suggests that evaluations of the benefits of captions for vocabulary acquisitions should take input-modality – test-modality congruency into account.
The images in television programs and the potential for learning unknown words
Authors: Rodgers Michael P.H.
Published: April 2020

Previous studies have indicated the potential for incidental vocabulary learning through viewing television. The assumption has been that the imagery in television helps learners acquire vocabulary because when they hear an unfamiliar word, the on-screen images provide semantic support. However, the extent to which imagery in authentic television supports learners in this way is unclear. This study examines 90 target words occurring in single seasons of television, and the degree to which their aural occurrence matched the presentation of a potentially supporting image. Results indicate differences in the way imagery supports potential vocabulary learning in documentary television compared with narrative television, and that this supporting imagery occurred concurrently with the aural form more often in documentary television. Research and pedagogical implications are discussed in detail.
Vocabulary knowledge and listening comprehension at an intermediate level in English and French as foreign languages
Authors: Noreillie Ann-Sophie , Kestemont Britta , Heylen Kris , Desmet Piet , Peters Elke
Published: April 2020

The present study aims to replicate Stæhr’s (2009) study on the relationship between vocabulary knowledge and listening comprehension. To explore the generalizability of Stæhr’s findings, two experiments were conducted. However, the study changed the population (Flemish learners) and proficiency level of the materials in the first experiment (intermediate) and also the language in the second experiment (French). Our results generally confirm Stæhr’s findings. We also found a positive correlation between vocabulary knowledge and listening comprehension. Although our findings reveal that learners probably need fewer words for adequate listening comprehension at an intermediate proficiency level, our study also showed that learners who knew more words had higher listening comprehension scores. Finally, our study seems to suggest that learners might need less lexical coverage for intermediate listening.
Suppression of individual peaks in two-colour high harmonic generation
Authors: Mitra S , Biswas S , Schötz J , Pisanty E , Förg B , Kavuri G A , Burger C , Okell W , Högner M , Pupeza I , Pervak V , Lewenstein M , Wnuk P , Kling M F
Published: April 2020

This work investigates the suppression of individual harmonics, simultaneously affecting specific even and odd orders in the high-harmonic spectra generated by strongly tailored, two-colour, multi-cycle laser pulses in neon. The resulting spectra are systematically studied as a function of the electric-field shape in a symmetry-broken (ω–2ω) and symmetry-preserved (ω–3ω) configuration. The peak suppression is reproduced by macroscopic strong-field approximation calculations and is found to be unique to symmetry-broken fields (ω–2ω). Additionally, semi-classical calculations further corroborate the observation and reveal their underlying mechanism, where a nontrivial spectral interference between subsequent asymmetric half-cycles is found to be responsible for the suppression.
Chirality relaxation in low-temperature strongly Rashba-coupled systems
Authors: Verpoort P C , Narayan V
Published: April 2020

We study the relaxation dynamics of non-equilibrium chirality distributions of charge carriers in Rashba systems. We find that at low temperature inter-Rashba band transitions become suppressed due to the combined effect of the Rashba momentum split and the chiral spin texture of a Rashba system. Specifically, we show that momentum exchange between carriers and the phonon bath is effectively absent at temperatures where the momentum of thermal phonons is less than twice the Rashba momentum. This allows us to identify inter-carrier scattering as the dominant process by which non-equilibrium chirality distributions relax. We show that the magnitude of inter-carrier scattering is strongly influenced by the opposing spin structure of the Rashba bands. Finally, we provide an explicit result for the inter-band relaxation timescale associated with inter-carrier Coulomb scattering. We develop a general framework and assess its implications for GeTe, a bulk Rashba semiconductor with a strong Rashba momentum split.
Can a highly accurate multi-class SSMVEP BCI induce sensory-motor rhythm in the sensorimotor area?
Authors: Zhang Xin , Xu Guanghua , Ravi Aravind , Pearce Sarah , Jiang Ning
Published: April 2020

Objective. Different visual stimuli might have different effects on the brain, e.g. the change of brightness, non-biological movement and biological movement. Approach. In this study, flicker, checkerboard and gaiting stimuli were chosen as visual stimuli to investigate whether steady-state motion visual evoked potential (SSMVEP) effect on the sensorimotor area for rehabilitation. The gaiting stimulus was designed as the gaiting sequence of a human. The hypothesis is that only observing the designed gaiting stimulus would simultaneously induce: (1) SSMVEP in the occipital area, similarly to an SSVEP stimulus; and (2) sensorimotor rhythm (SMR) in the primary sensorimotor area, because such action observation could activate the mirror neuron system. Canonical correlation analysis was used to detect SSMVEP from occipital electroencephalograms (EEG), and event-related spectral perturbation was used to identify SMR in the EEG from the sensorimotor area. Main results. The results showed that the designed gaiting stimulus-induced SSMVEP, with classification accuracies of 88.9 ± 12.0% in a four-class scenario. More importantly, it induced clear and sustained event-related desynchronization/synchronization (ERD/ERS), while no ERD/ERS could be observed when the other two SSVEP stimuli were used. Further, for participants with a sufficiently clear SSMVEP pattern (classification accuracy >85%), the ERD index values in the mu-beta band induced by the proposed gaiting stimulus were statistically different from those of the other two types of stimulus. Significance. Therefore, a novel brain–computer interface (BCI) based on the designed stimulus has potential in neurorehabilitation applications because it simultaneously has the high accuracy of an SSMVEP (sim90% accuracy in a four-class setup) and the ability to activate the sensorimotor area.
Research of the behavior of metal plates subject to ice ball
Authors: Orlov M Yu , Glazyrin V P , Orlov Yu N
Published: April 2020

The paper summarizes the results of ice destruction at shock loads (up to 1500 m/s). A brief literary review was sufficient for formulating research tasks, including impact experiment and a computational experiment. The results of impact experiment (≤159 m/s) were presented. The freezing temperature of ice samples varied from − 10°C to − 21°C. Similar pattern of ice destruction was noted in the quantitative test, which conducted especially for validation of the numerical method. The results of an underwater explosion of 4 kg of EE under 130-days-old “needle” ice cover are represented. Some capability of non-commercial software package is demonstrated. The impact resistance of single and double plates was qualitatively and quantitatively evaluated. It was established that the plates could protect against impact by an ice ball only up to 500 m/s.
Experimental studies of the deformation properties of frozen soils under static and dynamic loads
Authors: Balandin V V , Kochetkov A V , Krylov S V , Modin I A
Published: April 2020

The results of experimental studies of the deformation properties of sand of different water saturation are presented. The studies were conducted for frozen and unfrozen sand in static and dynamic loading conditions. The medium in all cases exhibits nonlinear properties. Dynamic strain diagrams were obtained using the Kolsky method in the split Hopkinson rod system. Static compression tests of sand were carried out in an elastic cage with registration of lateral pressure. The dynamic strain diagrams differ markedly from the static ones for both frozen sand and unfrozen sand. The level of stress in dynamic compression is much higher than in static. The diagrams of static deformation of frozen and unfrozen dry sand practically coincide. With increasing water saturation, the stress level for frozen and unfrozen sand increases.
Fractal geometry of the fatigue fracture surface of the ZTA composites
Authors: Korobenkov M V , Kiseleva T A
Published: April 2020

A fracture surface of the ceramic composite Al2O3 - ZrO2 at three-point bending during fatigue loading has been studied by scanning electron microscope. The bending strength and flexural modulus are derived under static conditions at a loading rate of 3 mm/min. The fatigue strength and fatigue limit are investigated at a frequency of 4 Hz in three stress ranges: 0.9, 0.8 and 0.7 of the average maximum static bending strengths. The surface fractal dimensions Df
is determined using triangulation method. It was shown that the surface relief can be characterized by fractal relief in the local approximation. The fractal dimensionality of the studied surface changes in the relatively narrow limits Df
= 2.653 - 2.742, for ceramic samples sintered at 1650 °C, and highly dependent on the number of cycles. The ceramic samples sintered at 1400 °C showed low resistance to fatigue loads with the fractal dimensionality Df
= 2.710 - 2.781, which are independent of the number of cycles.
Plastic strain localization in surface-hardened titanium polycrystals
Authors: Emelianova E S , Romanova V A
Published: April 2020

In this paper, features of plastic strain localization in commercial purity titanium surface-hardened by ultrasonic impact treatment (UIT) are numerically investigated. Three- dimensional polycrystalline structures inherent in unhardened and UIT surface-hardened titanium specimens are generated by a step-by-step packing method. For taking into account the deformation mechanisms at the micro- and mesoscales, constitutive equations describing a nonlinear behavior of individual grains are constructed using crystal plasticity theory. Quasi-static boundary value problems are solved in a dynamic statement using ABAQUS\Explicit finite-element package to simulate uniaxial tension of the model polycrystalline specimens. Based on the calculation results, conclusions are drawn on the effect of the UIT surface- hardened layer on the plastic strain localization and deformation-induced surface roughening in model polycrystals.
Software development network diagnostics industrial complexes
Authors: Narimanova G N , Zhuravlev V S , Narimanov R K , Zorkalcev A A
Published: April 2020

The article is devoted to the development of software for network diagnostics of industrial networks. The relevance of this topic is determined by the growing object of automated production. The reliability and effectiveness of their autonomous operation are directly related to the quality of remote monitoring and control of industrial complexes. The paper presents an assessment of the key parameters of the existing network diagnostics systems. Considered cross-platform, mobile technology used, the speed of reaction and the breadth of the functions implemented in the most common modern systems. A comparative analysis is given and the advantages of the software offered by the authors are shown.
Inorganic pigments based on transition-metal oxometallates for protective and decorative aluminophosphate-bonded coatings
Authors: Nazarova A Yu , Radishevskaya N I
Published: April 2020

Transition-metal oxometallate-based pigments deposited on a dispersed silicate mineral (marshalite, wollastonite) have a bright color and high light- and acid resistance. It is shown that these pigments can be used for protective and decorative aluminophosphate-bonded coatings. Thermal analysis performed on the thermal analyzer SDT Q600 shows that the structure of protective and decorative coatings remains unchanged to temperatures of about 900 °C. Optical studies (Axiovert 200M) demonstrate that colored coatings subjected to heat treatment have a uniform structure without cracks and, therefore, can be used for metal and concrete surfaces. X-ray diffraction (DRON-UM1 diffractometer, CuKα radiation) confirm that the coating contains AlPO4, Al(PO3)3 and Al(H2PO4)3 phases, quartz, and pigment. The insignificant amount of Al3(OH)3(PO4)2·H2O phase is detected.
To the study of vibration of materials with coatings in the presence of defects
Authors: Telyatnikov I S , Pavlova A V
Published: April 2020

In the paper a new method for studying the properties of deformable bodies with coatings is developed. We considered two models of the foundation: a homogeneous elastic layer with clamped lower edge and a two-layer packet containing a flat rigid inclusion located in the plane of the substrate elastic properties. We used the method of eigenfunctions in the study of the problem concerning steady-state oscillations of a deformable material with a cracked coating. For a foundation that does not contain defects, we described a method for the determination of main parameters characterizing the stress-strain state of a structure with a cracked coating composed of two long plates. We considered a continuous coating for the model of defective foundation. In the course of our study we obtained the relations for determining the characteristics of the stress-strain state of coating/substrate systems as well as presented an example of the application of the method for studying edge effects near the junction boundaries of a composite coating.
Determining non-stationary state of solid-propellant rocket engine model based on numerical conjugate problem solution
Authors: Zhukov A P , Belov S V , Ponomarev S V
Published: April 2020

This paper describes the solid-propellant rocket engine structure, including casing and filler. The gas flows within the filler channel. Based on numerical conjugate problem solution, non-stationary stress-strain states of the casing and filler were determined, as well as gas flow parameters in the channel. Within the conjugate problem, the engine is considered to be a two-component system: deformable solid body and gas. Conjugate problem solution involves specific subtasks related to the conjugation conditions, where Lagrangian approach is used for subtasks of solid body. Euler approach is used for subtasks of gas, implying immovable boundary of the computational domain on the integration time step. Numerical methods are applied in solving subtasks. Specific feature of conjugate problem solution algorithm is discrete movable domain boundary interface.
Taxonomy of uncertainty in environmental life cycle assessment of infrastructure projects
Authors: Saxe Shoshanna , Guven Gursans , Pereira Lucas , Arrigoni Alessandro , Opher Tamar , Roy Adrien , Arceo Aldrick , Von Raesfeld Sofia Sampedro , Duhamel Mel , McCabe Brenda , Panesar Daman K , MacLean Heather L , Posen I Daniel
Published: April 2020

Environmental life cycle assessment (LCA) is increasingly being used to evaluate infrastructure products and to inform their funding, design and construction. As such, recognition of study limitations and consideration of uncertainty are needed; however, most infrastructure LCAs still report deterministic values. Compared to other LCA subfields, infrastructure LCA has developed relatively recently and lags in adopting uncertainty analysis. This paper presents four broad categories of infrastructure LCA uncertainty. These contain 11 drivers focusing on differences between infrastructure and manufactured products. Identified categories and drivers are: application of ISO 14040/14044 standards (functional unit, reference flow, boundaries of analysis); spatiotemporal realities underlying physical construction (geography, local context, manufacturing time); nature of the construction industry (repetition of production, scale, and division of responsibilities); and characteristics of infrastructure projects (agglomeration of other products, and recurring embodied energy). Infrastructure products are typically large, one-off projects with no two being exactly alike in terms of form, function, temporal or spatial context. As a result, strong variability between products is the norm and much of the uncertainty is irreducible. Given the inability to make significant changes to an infrastructure project ex-post and the unique nature of infrastructure, ex-ante analysis is of particular importance. This paper articulates the key drivers of infrastructure specific LCA uncertainty laying the foundation for future refinement of uncertainty consideration for infrastructure. As LCA becomes an increasingly influential tool in decision making for infrastructure, uncertainty analysis must be standard practice, or we risk undermining the fundamental goal of reduced real-world negative environmental impacts.
Study of the Mechanical and Thermal Properties of PMMA/TiO2Nano Composite
Authors: Yaseen S. T. , Khaleel A. Sh.
Published: April 2020

This research investigates the effect of adding some reinforcing materials,including (nano and micro) titanium dioxide(TiO2)particles with different weight fraction(0.1,0.4,0.7,1,3 and5)% to polymethyl methacrylate (PMMA)and studying some mechanical and physical propertiesof composite material. Specimens’ of this project were prepared using (in-situ) method to form compositematerials. Themechanical tests were performed on these specimens,includingimpact test, thermal conductivity was performed as a physical test.Results of this study showed that the values of impact strength were decreased when adding the (nano-micro) particles in PMMA composite materials, while the values of thermal conductivity weredecreased.
Influence of Aluminum Fine Powder Content on the Some Mechanical Properties of Epoxy and Polyester Composites
Authors: Mohan Khadijh S , Awad Noor M , Hussein Wasan A , Farhan Ahmed J
Published: April 2020

In this study, the effect of aluminum powders on the some mechanical properties of epoxy (EP) and unsaturated polyester (UPE) composites was investigated. Aluminum powders (Al) were added to polymers with (0, 1, 3 and 5) %weight percentages. epoxy/Aluminum and unsaturated polyester/Aluminum composites were fabricated by the cast molding method. Maximum fracture forces, Maximum Extensions, Yield Points, Young Modulus, Tensile Strengths, flexural strength and ultimate compressive strength tests were performed on both composites. The results showed that the tensile strength of epoxy/Aluminum composites increased with increasing of additive percentage of Al powder, and the samples of EP/Al composite gained highest values of tensile strength (22.48 MPa) at ratio percent(5%). While the tensile strength of unsaturated polyester/Aluminum composites decreased with increasing of additive percentage of Al powder. Also the results showed that the samples of EP/Al composite gained highest values of flexural strength (58.63MPa) at weight percentage (1%).While the samples of UPE/Al composite gained highest values of flexural strength (91.88 MPa) at weight Percentage (3%). Finally, the value of compressive strength decreased with increasing of additive percentage of Al powder in both of EP/Al and UPE/Al composites.
Study The Improvement In The Dielectric Strength of (UPR/MgO) Nanocomposites
Authors: Zayza Malik J , Jubier Najwa J , Al –Bayaty Subhi A
Published: April 2020

This work focuses on the preparation of polymer matrix nanocomposite materials by hand lay-up molding which was prepared from the unsaturated polyester resin as matrix reinforced by nanoparticles of Magnesium Oxide(MgO) with particle size (54.19 nm) and weight fraction (0,1,3,5,7,10 and 15)%. Dielectric strength for the prepared samples was studied; the results of tests have shown the increase in the dielectric strength with increasing the weight fraction of additive (MgO) and also with the increases in the rate of voltage. The effect of the cycle’s number on the dielectric strength has noticed clearly after the first cycle.The images taken for the electric breakdown points by using optical microscopy has shown the sample coaled in the electric breakdown area as a result of polymeric chains of unsaturated polyester (UPR) destroyed, and there is an appearance of microcracks as a result of electric breakdown extends directly from the point of electric breakdown.
Evaluation of natural radioactivity in selected soil samples collected from northern regions of Oman
Authors: Al-Harmali A.
Published: April 2020

This study explores the radioactivity concentration in soil in the Northern regions of Oman. The naturally occurring radioactive nuclides of the main series, 238U, 232Th, 235U and 40K and artificial radionuclide 137Cs have been studied by means of low level gamma spectroscopy. Majority of the studied valleys (wadis) are descending from Super Hajar Mountains either towards its east part (coastal area) or the west part (desert). Soil samples were collected from headwaters and estuaries of wadis where residences and agriculture activities exist. In soil samples, the results showed that 238U radionuclide was presented in concentrations of the range (4.5 – 24.0) Bq.kg−1while 232Th was found in the range (2.4-20.6) Bq.kg−1. Ranges of 235U and 40K were reported as (0.6-2.5) Bq.kg−1 and (47-296) Bq.kg−1 respectively. Artificial radionuclide 137Cs was found in all soil samples in the range (2.8-11.9) Bq.kg−1. The hazard parameters, dose rate (D), annual effective dose (HR), equivalent radium activity (Raeq), internal hazard index (Hin), external hazard index (Hex) and gamma representative level index (Iγr) were all calculated. The values of D, HR and Raeq were found in the ranges (6.6-33.5) nGy/h, (0.8-4.1)*10−2 mSv/yr and (17.2-88.6) Bq.kg−1 respectively. The values of Hin, Hex and Iγr were all less than 1. These obtained results remained below the optimum admissible values according to UNSCEAR.. The results indicate that the radiation hazard from naturally and artificially radionuclides in soil samples from the area studied in this current work is not significant.