bluuebunny/crossref_metadata_2025 huggingface dataset:
Ternary superconducting cophosphorus hydrides stabilized via lithium
Authors: Shao Ziji , Duan Defang , Ma Yanbin , Yu Hongyu , Song Hao , Xie Hui , Li Da , Tian Fubo , Liu Bingbing , Cui Tian
Published: October 2019

Inspired by the diverse properties of sulfur hydrides and phosphorus hydrides, we combine first-principles calculations with structure prediction to search for stable structures of Li−P−H ternary compounds at high pressures with the aim of finding novel superconductors. It is found that phosphorus hydrides can be stabilized under pressure via additional doped lithium. Four stable stoichiometries LiPH3, LiPH4, LiPH6, and LiPH7 are uncovered in the pressure range of 100–300 GPa. Notably, we find an atomic LiPH6 with $$Pm\overline 3$$

P
m

3

¯

symmetry which is predicted to be a potential high-temperature superconductor with a Tc value of 150–167 K at 200 GPa and the Tc decreases upon compression. All the predicted stable ternary hydrides contain the P–H covalent frameworks with ionic lithium staying beside, but not for $$Pm\overline 3$$

P
m

3

¯

-LiPH6. We proposed a possible synthesis route for ternary lithium phosphorus hydrides: LiP + H2 → LiPHn, which could provide helpful and clear guidance to further experimental studies. Our work may provide some advice on further investigations on ternary superconductive hydrides at high pressure.
Author Correction: Quantum computing with graphene plasmons
Authors: Alonso Calafell I. , Cox J. D. , Radonjić M. , Saavedra J. R. M. , García de Abajo F. J. , Rozema L. A. , Walther P.
Published: October 2019

An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Chemical and sensory analysis of commercial Navel oranges in California
Authors: Simons Tyler , McNeil Christopher , Pham Vi D. , Wang Siyu , Wang Yu , Slupsky Carolyn , Guinard Jean-Xavier
Published: October 2019

Seven lots of commercially available Navel oranges grown in California were evaluated with flavoromic, metabolomic, sensory descriptive analysis, and consumer testing techniques to identify sensory and chemical drivers of liking. Eight identified chemical clusters related to numerous sensory attributes and consumer preferences. Differences in adult and child preferences led to the discovery of six consumer clusters (four adult and two child). Sweetness, overall flavor, sourness, fruity flavor, and juiciness were identified as the main sensory drivers of liking for the consumers. Fructose, glucose, and proline were among the compounds that best explained perceived sweetness while sourness was correlated with citrate and ascorbate. Perceived fruity flavor increased with higher concentrations of ethanol. We conclude that consumers differ in their preferences for Navel oranges and desire fruit that is higher in both sweetness and sourness.
Late Gadolinium Enhancement Predicts Improvement in Global Longitudinal Strain after Aortic Valve Replacement in Aortic Stenosis
Authors: Fujimiya Tsuyoshi , Iwai-Takano Masumi , Igarashi Takashi , Shinjo Hiroharu , Ishida Keiichi , Takase Shinya , Yokoyama Hitoshi
Published: October 2019

Myocardial fibrosis, as detected by late gadolinium enhancement (LGE) magnetic resonance imaging (MRI), is related to mortality after aortic valve replacement (AVR). This study aimed to determine whether LGEMRI predicts improvement in global longitudinal strain (GLS) after AVR in patients with severe aortic stenosis (AS). Twenty-nine patients with severe AS who were scheduled to undergo AVR were enrolled. Two-dimensional echocardiography and contrast-enhanced MRI were performed before AVR. GLS and LGEcore (g: > 5 SD of normal area), LGEgray (g: 2–5 SD), and LGEcore+gray (g) were measured. One year after AVR, GLS were examined by echocardiography to assess improvement in LV function. Preoperatively, GLS correlated with LGEcore (g) (r2 = 0.14, p < 0.05), LGEgray (g) (r2 = 0.32, p < 0.01) and LGEcore+gray (g) (r2 = 0.36, p < 0.01). LGEcore was significantly lower in patients with improved GLS after AVR (GLS1year ≥ −19.9%) compared to those with no improvement (1.34 g vs. 4.70 g, p < 0.01). LGE predicts improvement in LV systolic function after AVR.
A 96-multiplex capillary electrophoresis screening platform for product based evolution of P450 BM3
Authors: Gärtner Anna , Ruff Anna Joëlle , Schwaneberg Ulrich
Published: October 2019

The main challenge that prevents a broader application of directed enzyme evolution is the lack of high-throughput screening systems with universal product analytics. Most directed evolution campaigns employ screening systems based on colorimetric or fluorogenic surrogate substrates or universal quantification methods such as nuclear magnetic resonance spectroscopy or mass spectrometry, which have not been advanced to achieve a high-throughput. Capillary electrophoresis with a universal UV-based product detection is a promising analytical tool to quantify product formation. Usage of a multiplex system allows the simultaneous measurement with 96 capillaries. A 96-multiplexed capillary electrophoresis (MP-CE) enables a throughput that is comparable to traditional direct evolution campaigns employing 96-well microtiter plates. Here, we report for the first time the usage of a MP-CE system for directed P450 BM3 evolution towards increased product formation (oxidation of alpha-isophorone to 4-hydroxy-isophorone; highest reached total turnover number after evolution campaign: 7120 mol4-OHmolP450−1). The MP-CE platform was 3.5-fold more efficient in identification of beneficial variants than the standard cofactor (NADPH) screening system.
Magnetotrichography: Measuring the dc magnetic field produced by hair follicles
Authors: Khan Sheraz , Cohen David
Published: October 2019

We here describe the dc magnetic field over the human head produced by healthy hair follicles when the scalp is lightly pressed. This phenomenon was briefly reported decades earlier, where a double-planar SQUID (Superconducting Quantum Interference Devices) gradiometer at a single location was used. We here perform a larger study, using the dcMEG containing 102 double-planar gradiometers covering the whole scalp. The field is displayed as an on-line arrow map over the head, showing the approximate flow of direct current (dc) in the scalp. Standard sets of five arrow maps per subject were measured, where the subject successively pressed parts of their head against the inside of the helmet. These maps were made for 15 normal subjects (5 females), and 2 with alopecia (non-functioning follicles). The directions of “pressed” generating arrows always followed the natural tilt of the follicles, verifying the follicles as generators, with a time constant of about one second. The maximum generator dipole strength was about 24 µA-cm. Scalp electric potentials corresponding to the magnetic signals were masked by much larger electrodermal potentials. Therefore, this magnetic method, called magnetotrichography, is unique in measuring this follicular electrical activity, with possible applications in studying baldness and hair diseases.
Metabolomic studies in tissues of mice treated with amifostine and exposed to gamma-radiation
Authors: Cheema Amrita K. , Li Yaoxiang , Girgis Michael , Jayatilake Meth , Simas Madison , Wise Stephen Y. , Olabisi Ayodele O. , Seed Thomas M. , Singh Vijay K.
Published: October 2019

Although multiple radioprotectors are currently being investigated preclinically for efficacy and safety, few studies have investigated concomitant metabolic changes. This study examines the effects of amifostine on the metabolic profiles in tissues of mice exposed to cobalt-60 total-body gamma-radiation. Global metabolomic and lipidomic changes were analyzed using ultra-performance liquid chromatography (UPLC) quadrupole time-of-flight mass spectrometry (QTOF-MS) in bone marrow, jejunum, and lung samples of amifostine-treated and saline-treated control mice. Results demonstrate that radiation exposure leads to tissue specific metabolic responses that were corrected in part by treatment with amifostine in a drug-dose dependent manner. Bone marrow exhibited robust responses to radiation and was also highly responsive to protective effects of amifostine, while jejunum and lung showed only modest changes. Treatment with amifostine at 200 mg/kg prior to irradiation seemed to impart maximum survival benefit, while the lower dose of 50 mg/kg offered only limited survival benefit. These findings show that the administration of amifostine causes metabolic shifts that would provide an overall benefit to radiation injury and underscore the utility of metabolomics and lipidomics to determine the underlying physiological mechanisms involved in the radioprotective efficacy of amifostine. This approach may be helpful in identifying biomarkers for radioprotective efficacy of amifostine and other countermeasures under development.
Nanoscale true random bit generator based on magnetic state transitions in magnetic tunnel junctions
Authors: Jenkins Alex S. , Alvarez Lara San Emeterio , Freitas Paulo P. , Ferreira Ricardo
Published: October 2019

We present an investigation into the in-plane field induced free layer state transitions found in magnetic tunnel junctions. By applying an ac current into an integrated field antenna, the magnetisation of the free layer can be switched between the magnetic vortex state and the quasi-uniform anti-parallel state. When in the magnetic vortex state, the vortex core gyrates a discrete number of times, and at certain frequencies there is a 50% chance of the core gyrating n or n − 1 times, leading to the proposal of a novel nanoscale continuous digital true random bit generator.
FRET-based cyclic GMP biosensors measure low cGMP concentrations in cardiomyocytes and neurons
Authors: Calamera Gaia , Li Dan , Ulsund Andrea Hembre , Kim Jeong Joo , Neely Oliver C. , Moltzau Lise Román , Bjørnerem Marianne , Paterson David , Kim Choel , Levy Finn Olav , Andressen Kjetil Wessel
Published: October 2019

Several FRET (fluorescence resonance energy transfer)-based biosensors for intracellular detection of cyclic nucleotides have been designed in the past decade. However, few such biosensors are available for cGMP, and even fewer that detect low nanomolar cGMP concentrations. Our aim was to develop a FRET-based cGMP biosensor with high affinity for cGMP as a tool for intracellular signaling studies. We used the carboxyl-terminal cyclic nucleotide binding domain of Plasmodium falciparum cGMP-dependent protein kinase (PKG) flanked by different FRET pairs to generate two cGMP biosensors (Yellow PfPKG and Red PfPKG). Here, we report that these cGMP biosensors display high affinity for cGMP (EC50 of 23 ± 3 nM) and detect cGMP produced through soluble guanylyl cyclase and guanylyl cyclase A in stellate ganglion neurons and guanylyl cyclase B in cardiomyocytes. These biosensors are therefore optimal tools for real-time measurements of low concentrations of cGMP in living cells.
Emergence and full 3D-imaging of nodal boundary Seifert surfaces in 4D topological matter
Authors: Li Linhu , Lee Ching Hua , Gong Jiangbin
Published: October 2019

The topological classification of nodal links and knot has enamored physicists and mathematicians alike, both for its mathematical elegance and implications on optical and transport phenomena. Central to this pursuit is the Seifert surface bounding the link/knot, which has for long remained a mathematical abstraction. Here we propose an experimentally realistic setup where Seifert surfaces emerge as boundary states of 4D topological systems constructed by stacking 3D nodal line systems along a 4th quasimomentum. We provide an explicit realization with 4D circuit lattices, which are freed from symmetry constraints and are readily tunable due to the dimension and distance agnostic nature of circuit connections. Importantly, their Seifert surfaces can be imaged in 3D via their pronounced impedance peaks, and are directly related to knot invariants like the Alexander polynomial and knot Signature. This work thus unleashes the great potential of Seifert surfaces as sophisticated yet accessible tools in exotic bandstructure studies.
Borohydride stabilized gold–silver bimetallic nanocatalysts for highly efficient 4-nitrophenol reduction
Authors: Larm Nathaniel E. , Thon Jason A. , Vazmitsel Yahor , Atwood Jerry L. , Baker Gary A.
Published: October 2019

Bimetallic AuxAg1−x nanoparticles, prepared using sodium borohydride as the sole reducing and capping agent for various NaBH4:metal molar ratios, were investigated as catalysts for 4-nitrophenol reduction.
X-ray total scattering study of magic-size clusters and quantum dots of cadmium sulphide
Authors: Tan Lei , Misquitta Alston J. , Sapelkin Andrei , Fang Le , Wilson Rory M. , Keeble Dean S. , Zhang Baowei , Zhu Tingting , Riehle Frank S. , Han Shuo , Yu Kui , Dove Martin T.
Published: October 2019

Four types of magic-size CdS clusters and three different CdS quantum dots have been studied using the technique of X-ray total scattering and pair distribution function analysis.
Increasing dielectric loss of a graphene oxide nanoparticle to enhance the microwave thermoacoustic imaging contrast of breast tumor
Authors: Yuan Chang , Qin Baohua , Qin Huan , Xing Da
Published: October 2019

Microwave-induced thermoacoustic imaging (MTAI) utilizes the high dielectric contrast of tissues in the microwave range, and, combined with the high resolution of ultrasound imaging, can noninvasively obtain anatomical and functional structure information.
A wrinkled structure with broadband and omnidirectional light-trapping abilities for improving the performance of organic solar cells with low defect density
Authors: Liu Kong , Sun Yang , Li Qicong , Yang Cheng , Azam Muhammad , Wang Zhijie , Qu Shengchun , Wang Zhanguo
Published: October 2019

A wrinkled structure could enhance omnidirectional light absorption in the organic active layer and charge transport efficiency at the interface.
A strong organic electron donor incorporating highly π-donating triphenylphosphonium ylidyl substituents
Authors: Burgoyne Morgan M. , MacDougall Thomas M. , Haines Zachary N. , Conrad Jordan W. , Calhoun Larry A. , Decken Andreas , Dyker C. Adam
Published: October 2019

The use of Ph3PCH–, the most donating substituent yet quantified, makes B more reducing than D or E and causes hindered bond rotation in A and C.
A Tutorial of the Current Treatment Modalities and Voice Management in Laryngeal Cancer
Authors: Regan Kathryn , Joshi Ashwini
Published: October 2019

Purpose

The purpose of this tutorial was to provide speech-language pathologists unfamiliar with the rehabilitation of laryngeal cancer a basic understanding of laryngeal cancer and the factors involved in the treatment of the voice.

Conclusion

This tutorial provides an overview of the types and subsites of laryngeal cancer, risk factors, stages and prognosis, and treatment options at these stages. The readers will gain the foundational knowledge necessary to work with this population and a starting point for further study. More research is needed regarding voice outcomes and the benefits of voice therapy in combination with the available laryngeal cancer treatment modalities so that we may better serve these patients.
Coordinated control strategy of multi‐terminal VSC‐HVDC system considering frequency stability and power sharing
Authors: Liu Yingpei , Xie Sai , Liang Haiping , Cui Hanyang
Published: October 2019

Aiming at the power sharing among converter stations and the frequency stability of weak AC system connected by converter stations in multi‐terminal voltage source converter high‐voltage direct current (VSC‐HVDC) system, a coordinated control strategy without communication is proposed, which can realise the bidirectional active power support between DC system and weak AC system. The strategy divides the voltage of DC system and the frequency of weak AC system into open‐time operation area and time‐limited operation area, respectively. When DC voltage and AC frequency are in the open‐time operation area, respectively, unbalanced power in the system can be flexibly allocated according to the power margins of converter stations, which reduces DC voltage fluctuation and the influence of DC voltage errors (line length and other factors) among the converter stations on power regulation. When the AC frequency is in the time‐limited operation area, the DC system can provide power support for the weak AC system to maintain frequency stability. When the DC voltage is in the time‐limited operation area, the weak AC system loses part of the frequency quality to provide short‐term power support for the DC system to maintain the stability of VSC‐HVDC system as far as possible. The simulation results have verified the feasibility and effectiveness of the proposed control strategy.
FASD based on BSC method for distribution networks
Authors: Zheng Ze‐Yin , Guo Mou‐Fa , Yang Nien‐Che , Jin Tao
Published: October 2019

A Petersen coil was used as a passive arc‐suppression device (ASD) to mitigate ground‐fault current when a single‐phase‐to‐ground fault occurred in distribution networks. However, passive ASDs cannot compensate for the active and harmonic components of ground‐fault current. Furthermore, a massive residual ground‐fault current would endanger human life and the reliable operation of distribution networks. To overcome the shortcomings of passive ASDs, a three‐phase flexible ASD (FASD) with a three‐phase cascaded H‐bridge topology was presented. A three‐phase FASD connected to a bus bar of distribution networks was employed to compensate for the ground‐fault current. In this study, the FASD with the backstepping control (BSC) based on current‐compensation principle was proposed to completely eliminate the ground‐fault current. The effectiveness of the proposed FASD with the BSC method was verified using the simulation and experimental results.
Optimisation analysis of pulmonary nodule diagnostic test based on deep belief nets
Authors: Yang Wei , Xia Wenhua , Xie Yuanliang , Mao Shilong , Li Rong
Published: October 2019

At present, the rate of missed diagnosis of lung cancer is high. The reason is that the pulmonary nodule phenomenon cannot be effectively monitored due to various interference factors in the actual detection process. In order to improve the detection accuracy, this study combined with the actual situation to analyse the diversity of nodular shape and constructed a deep belief network‐based diagnosis model for pulmonary nodules. At the same time, in order to improve the detection effect, this study sets the model to have multi‐layer non‐linear structure and analyses the previous clinical data to improve the model learning rate and training effect. In addition, in order to verify the performance of the model, the diagnostic effect of the model is studied by comparative experiments. The research shows that the model proposed in this study is higher than the traditional algorithm in detection accuracy, which can provide theoretical reference for subsequent related research.
Design of a dry inorganic substances dispenser
Authors: Filippov Dmitry A. , Moiseev Arkadiy V.
Published: October 2019

The article is devoted to the introduction of dry inorganic substances, mixtures, complex solids on field surface or on the object of treatment by a universal dispenser. The article has a research character which is expressed in the fact that the analysis of methods and means for the introduction of dry inorganic substances as well as extracts from the works of leading scientists on the subject are given, promising scientific developments in the form of patent analysis which provide optimal flow of the technological process are shown, their shortcomings and solutions to these problems are pointed. There was justified the main tendency of development of dispensers and improvement of their designs for advancing the quality rates of their work. Also, there was shown the type of the proposed design, its description and the flow of the technological process. As a result of the work done, there was obtained the design of the dispenser of dry inorganic substances with proposed working elements. The conclusions set out the main results achieved so far.
Fire exoskeleton to facilitate the work of the fireman
Authors: Osipov Arthur
Published: October 2019

Classification of existing exoskeletons is given, variants of their possible application are considered. The review of fire exoskeletons is presented, their design features are given. Advantages and disadvantages of fire exoskeletons are analyzed. The stability of the robotic device is proved by calculation. The concept of fire exoskeleton-nozzleman to facilitate the work of firefighters is proposed. As a result of computational-analytical and practical researches, the concept of a fire exoskeleton-nozzleman is developed for simplification of operative work of the nozzleman during a fire. Practical application of the exoskeleton-nozzleman firefighter allows to normalize the working conditions of the nozzleman, to release three combat units of the personnel, to increase the efficiency of firefighting.
Designing soil tillage devices for the spiral land cultivation system
Authors: Strekalov Sergey , Strekalova Lubov
Published: October 2019

The paper considers ways of implementing scientific and technological achievements in crop farming by focusing on soil tillage and plant management operations. It studies requirements to soil tillage device designs and lists efficiency criteria for their operation. Theoretical research is being conducted into finding monoprinciples for creating multifunctional devices for the spiral crop farming system. A synthesis of principally new wave-motion-based tools is presented. The critical operational characteristics of wave-type tools and their technological aspects are given.
Harvesting seed crops: evaluating quality of combined harvesters’ operation
Authors: Podzorov Aliksey , Pekhalskii Igor
Published: October 2019

The analysis of the bunker grain collected by various combine harvesters in the conditions of ordinary operation on cleaning of seed crops of grain crops is carried out. Evaluated the purity of the bunker heap, crushing grain, clogged with other seeds. Evaluation of the quality of the bunker heap was carried out on three domestic and seven foreign models of combines. Suggested ways to solve the problem of improving the quality of seed.
Justification of the type of combine harvester for farms
Authors: Golovkov Aleksandr , Moskovskiy Maksim , Khamuev Victor
Published: October 2019

We presented results of the tests of combine harvesters of domestic and foreign manufacturers over the past ten years. We presented recommendation about the choice of the studied technology
Possible ways of technogenic formations processing with zinc extraction from sulphide compounds
Authors: Mikheenkov Mikhail , Sheshukov Oleg , Nekrasov Ilya
Published: October 2019

Extraction of zinc from sulphide forms by pyrometallurgical methods is difficult due to the high energy of the “zinc-sulfur” bond. Theoretically justified and experimentally confirmed the possible methods of extracting zinc from such compounds by changing of raw material phase composition. The zinc oxide obtained by this way has high purity and does not require additional purification by hydrochemical methods.
Theoretical justification of fruit separation rolling process by a planetary fruit separator
Authors: Ablikov Victor A. , Castidi Yuri K. , Klinova Daria M.
Published: October 2019

The article is devoted to the theoretical justification of the process of rolling stems by planetaryrollers of the fruit separator in the harvesting of Solanaceae vegetables as reusable as at direct fullharvest. The article has a theoretical, research character, expressed in the fact that the issue of Solanaceae vegetables harvesting was theoretically considered, the analysis of methods and means for the introduction of dry inorganic substances was given, when considering the process of rolling stems of Solanaceae vegetables as a rolling of elastic–plastic material there were obtained the dependencesthat determine the kinematic and energy parameters of planetary multi–rolling fruit separators.The conclusions set out the main results achieved so far. The type of the proposed design was theoretically justified, its description and the flow of the technological process were given. As a result of the work done, the process of fruit removal from a plant with offered working elements was shown.
Methodological measurement basis environmental safety in construction and operation of water management facilities
Authors: Bondarenko V.L. , Hecuriani E.D. , Klimenko O. V. , Semenova E.A.
Published: October 2019

Based on the results of monitoring studies of existing and under construction water management facilities within the basin geosystems of the Kuban, Lower Don and Terek river, using a systematic approachof developing methodological framework for assessing environmental safety in space and time on the model of the system “OP-SES-PM”, in which the vector properties are determined by the structure of this system. Taking the water management facility as a source of environmental safety, the concept of environmental safety is defined. Which is interconnected with the ecological state of the water managementfacility, considered as an “object of activity, as part of the environmental-technical system” “Natural environment-Object of activity-Population”. Based on the analysis of the processes of interaction between the components of the system “OP-SESPM” conceptual statements ofenvironmental safety have been formulated
The Formation of a Dispersed Gas System in the Flotation Cells
Authors: Alekseev E.V.
Published: October 2019

The use of flotation methods for wastewater treatment is due to their advantages in comparison with other methods of gravity separation, for example, sedimentation. The advantages of flotation water treatment methods include the high speed of the separation process, the ability to extract impurities that are close in density to water, environmental friendliness. Flotation methods are based on adsorptive bubble separation processes. Accordingly, the performance of a particular flotator directly depends on the conditions for the implementation of these processes in a particular flotation cell. The aim of the research was to study the relationship between the dispersed gas phase (DGP) and the ratio of the geometric dimensions of the flotation cells based on the proposed shape indicator of the flotation cell. Studies performed on the experimental model of the flotator have established a significant influence of theshape indicator of the flotation cell on such important indicators of the adsorptive bubble separation processes as gas-filling and the DGP floating speed. The evaluation of different forms of flotation cells, in relation to the properties of extracted bubble-particle complexes is given.
The study of the aerodynamic characteristics of dust particles in the air of roadside areas
Authors: Vasiliev Anatoly , Stefanenko Igor , Azarov Valery , Nikolenko Denis
Published: October 2019

The article addresses issues, which are related to the determination of aerodynamic characteristics of dust particles in roadside air areas. Was studied dustiness of Volgograd roadside areas.
Determination methodology of the subsidence speed of small-dispersed particles of different ranges of storage facilities by visual recording
Authors: Azarov Valeriy , Dobrinskiy Daniil , Lupinogin Vladislav , Sakharova Anastasia
Published: October 2019

Was researched a small-dispersed dust from storage facilities in differend ranges. Was carried out acomparative analysis of the subsidence speed of the obtained particle sizes. The laboratory installation was upgraded and was installed the automatic sample dumping, and video recorder with the possibility of enlarging the image and manual focusing. Due to implementation of additional elements in the design of the installation, it was possible to exclude mechanical interference and simplify the design of the equipment. At the same time, it was possible to minimize coverage error during the experiment. The mainaim was to determine the dispersal composition with a recording on video equipment with subsequent processing of the obtained data.
A comparative analysis of several material models in LS-DYNA at high velocity impact
Authors: Bakulina Arina , Buzyurkin Andrey
Published: October 2019

The questions of application of the LS-DYNA finite element analysis package for describing the interaction of a spherical projectile and a massive metal obstacle are considered. Based on a comparison of the results of numerical simulation with experimental data, a qualitative possibility has been shown to determine the magnitude of the dynamic hardness of the obstacle material.A simulation of the collision of a spherical impactor and a massive metal barrier shaped as a cube is performed. Data are obtained on the penetration of the striker into the barrier.Using the simulation curve, the values of the dynamic hardness of the obstacle were restored and a comparison was made with their experimental values. The qualitative correspondence is shown.
Influence of fracture incubation time on dynamic crack propagation in brittle solids
Authors: Grigoriev Aleksandr , Shilko Evgeny
Published: October 2019

The paper is devoted to theoretical study of the longitudinal shear (mode II) crack unstable growth dynamics in brittle materials. We considered two main regimes of the dynamic propagation of the crack (sub-Rayleigh and supershear) and their implementation conditions. The research was carried out by computer simulation with the Movable Cellular Automaton method, using the generalized kinetic fracture model, which takes into account the finite duration of local fracture (fracture incubation time). It is shown that the fracture incubation time is a key parameter, which determines the transition conditions of the shear crack growth process from the sub-Rayleigh regime to supershear.
Structural-phenomenological stress-strain model for concrete
Authors: Danilov Maksim , Bardaev Pavel
Published: October 2019

This work is devoted to the improvement mathematical apparatus for describing the stress-strain state of structures made of heterogeneous materials and modeling the processes of their deformation under load. The proposed mathematical model establishes the relationship between the components of the macrostrains tensor and the components of the macrostress tensor and explicitly takes into account the heterogeneity of the material. The model can be used in finite-elemental software packages.
The numerical study of the influence of material parameters on the regime of adhesive wear of surface asperities
Authors: Dudkin Ivan , Shilko Evgeny , Dimaki Andrey , Popov Valentin
Published: October 2019

In the paper, we developed a discrete element model of adhesive interaction of materials with taking into account the “cold welding” effect. Based on this model, we carried out a detailed analysis of the factors controlling regimes of adhesive wear for elastic-plastic materials with non-ideal plasticity. We proposed an empirical criterion of transition from “breakaway” to “grinding” regime of wear. The extended form of the given criterion takes into account the dependence of material strength on hydrostatic pressure.
Comparison of the resistance of monolithic and layered heterogeneous barriers to penetration by rigid and deformable strikers with an ogival nose based on numerical simulation
Authors: Kraus Evgeny , Shabalin Ivan
Published: October 2019

To create protective elements, information is needed on the resistance of various combinations of metal, ceramic, and heterogeneous plates, including layered ones, both in contact and with spacing. In addition, an intensive process is underway to create complex materials such as cermet composites. In this work, for verification of the code, numerical calculations of the breakdown of both monolithic and layered steel barriers by a striker with an ogival nose are performed. A series of 2D and 3D calculations for modeling the processes of penetrating heterogeneous barriers has been performed. It is shown that the resistance of heterogeneous barriers to penetration by a rigid striker is approximately the same, whereas the impact of a deformable striker on heterogeneous barriers shows that the resistance of layered barriers is lower compared to a monolithic barrier, and spacing of layers reduces the resistance of the barrier.
Simulation of benzylpenicillin molecule distribution in slit-shaped Si nanopores
Authors: Kryzhevich Dmitrij , Zolnikov Konstantin , Korchuganov Aleksandr , Tsukanov Alexey , Lotkov Aleksandr
Published: October 2019

A molecular dynamics study of the behavior of benzylpenicillin molecules in slit-shaped nanopores was carried out. A model silicon material with a pore size from 10 to 50 nm was chosen as a nanoporous structure. The interaction between benzylpenicillin molecules was described by a pair potential, built on the basis of modelling the molecule behavior by all-atom force fields. It was shown that an adsorbed layer of benzylpenicillin molecules is formed near the pore walls. With a decrease in the pore size, the maximum density of molecules in the adsorbed layer decreases, while the fraction of adsorbed molecules in the whole pore increases.
Numerical Modeling of Stress-Strain State of a Deep Beam
Authors: Mescheulov Nikita , Barashkov Vladimir
Published: October 2019

The article presents calculation results for model elastic problem of defining stress-strain state of a deep beam preformed in 3D and 2D statements with the use of ANSYS software package. Geometric relations are taken in the form of Cauchy equations. The purpose of the study is to assess error in the results obtained for the two statements and to draw a conclusion on the possibility of using 2D statement for the deep beam under study. Based on 3D statement calculation results one may observe a short area near the support surface of a deep beam with the maximum load across the entire thickness. In this area the concentration of maximum stress values and maximum linear and angular deformations in the structure material are observed. The area is located on the axis of symmetry of the deep beam near the inner edge of support surface. It is found that the stress intensity values obtained for the two statements have considerable differences in this area, for that reason 3D statement shall be used when performing calculations for the deep beam. This way of solving the problem is illustrative of stress-strain state parameters distribution across the thickness of the structure, which is necessary for its strength evaluation.
Numerical simulation of fatigue failure of composite materials under compression
Authors: Petrov Mark
Published: October 2019

The process of fatigue fracture of carbon fibres reinforced plastic under compressive loads is considered from the standpoint of the theory of reaction rates. Numerical simulation is based on rheological structural models of the material, which reproduce thermodynamic processes of local plastic deformation and failure occurring in time. The prediction of longevity of composite materials under compressive loads is similar to the solution of the problem for metal alloys under tensile loads when temperature and stresses are arbitrary functions of time.
Research of brick dynamic strength when subjected to shock loading by method of computer modelling
Authors: Plyaskin Andrei , Belov Nikolai , Yugov Nikolai , Ryshkov Artem , Yugov Aleksei , Matskevich Nina
Published: October 2019

The study represents the mathematical model of distorting and destruction of ordinary brick and masonry when subjected to shock-wave loadings. The research of the impact dynamic strength of the masonry's two fragments to the steel drop-weight of 1-2 m, weighing 197-1000 kg, was conducted by using the method of the computer modelling.
Modeling of the interaction of the layered barrier with a high-speed fragment
Authors: Ishchenko Alexandr , Belov Nikolay , Burkin Viktor , Sammel Anton , Yugov Nikolay , Khabibullin Marat
Published: October 2019

For the manufacture of transparent armor of high class protection, as a rule, reinforced silicate glasses, as well as transparent ceramics, are used. Since these materials are resiliently brittle, they can be used only in transparent multilayered barriers with protective back films for protection against high-speed fragmentation elements and bullets. Plexiglass or polycarbonate is most often used as the back layer. The barrier’s face layer must have a hardness substantially higher than the hardness of the drummer’s material, and the Hugonievskii elasticity limit must exceed the shock-wave pressure arising at the initial stage in the barrier. The purpose of this paper is to develop a mathematical model that allows, within the framework of a porous elastic-plastic medium with regard to various fracture mechanisms, to calculate the impact interaction of fragmentation elements with transparent armor. Numerical research was conducted with the help of copyright software systems. Experimental studies of the collision of transparent armor with a splinter simulator in the speed range of 1500 ... 2500 m / s were carried out with the use of throwing installations of the NRI AMM TSU.
Neuro-vaskuläre Komplikationen bei komplexen Korrektureingriffen − Ursachen, Prävention, Systemlösungen
Authors: Koller Heiko , Shiban Ehab , Bodon Gergely , Wostrack Maria , Krieg Sandro , Meiners Thomas , Meyer Bernhard
Published: October 2019

Die Autoren präsentieren eine ausführliche Übersichtsarbeit, welche Einblicke in die Pathogenese, Prävention und Therapie neurovaskulärer Komplikationen in der Behandlung komplexer spinaler Pathologien ermöglicht. Insbesondere werden die strategischen Grundzüge für die Vermeidung neurologischer Läsionen bei Patienten mit komplexen Deformitäteneingriff an der Wirbelsäule und mit neurologische erhöhten Risiko dargestellt.
Dankschreiben an Palliativteams
Authors: Zwingmann Christian , Berthold Daniel , Gramm Jan
Published: October 2019

Hintergrund Um Angehörige im Rahmen von Palliative Care gezielt unterstützen zu können, müssen ihre Bedürfnisse bekannt sein. Bisherige Befragungen stellen Informationsbedürfnisse heraus. Lassen sich weitere Angehörigenbedürfnisse über eine Analyse ihrer Dankschreiben an das Palliativteam erschließen?

Methodik Aus einer Sammlung von Dankschreiben wurden in einem mehrschrittigen Prozess 63 Schreiben ausgewählt. Nach einer Kategorienentwicklung gemäß den Prinzipien der Qualitativen Inhaltsanalyse wurden die Schreiben codiert. Anschließend wurden die Häufigkeiten der Kategorien ermittelt.

Ergebnisse Die Angehörigen bedanken sich vor allem, dass sie selbst Trost/Zuwendung erfahren und sich aufgehoben gefühlt haben sowie für die pflegerische/medizinische Versorgung und menschenwürdige Behandlung des Patienten. Hinsichtlich des eigenen Befindens schildern sie am häufigsten die Erfahrung des Verlusts.

Schlussfolgerung Die Angehörigen äußern ein starkes Bedürfnis nach emotionaler Unterstützung. Die Analyse der Dankschreiben erschließt somit einen zusätzlichen Bedürfnisschwerpunkt. Zudem sollten die Trauerreaktionen der Angehörigen beachtet werden.
Universality in numerical computation with random data: Case studies and analytical results
Authors: Deift Percy , Trogdon Thomas
Published: October 2019

In this paper, the authors discuss various results on universality in numerical computation with random data, obtained by the authors and their collaborators—C. Pfrang, G. Menon, S. Olver, and S. Miller—at various stages over the last 6–7 years. This paper follows closely the plenary talk with the same title given by the first author at ICMP Montreal 2018. The reader wishing to follow more closely the evolution and development of the ideas in this paper is invited to consult Deift et al. in the arXiv 2012–2019.
Improved etching technique for creating sapphire nanostructures
Authors: Mandel Savannah
Published: October 2019

Researchers experimented with multi-level etching masks and achieved a nine-fold increase in sapphire etching depth, which may lead to new applications in photonics, optoelectronics and other multifunctional materials.
First time-resolved measurements of ions from extreme ultraviolet-induced plasmas
Authors: Mandel Savannah
Published: October 2019

Scientists unravel the mysteries of extreme ultraviolet induced plasmas using time resolved measurements and observe new and unexpected plasma dynamics.
A Sogdian Drinking Game at Panjikent
Authors: Hensellek Betty
Published: October 2019

This article reconsiders the religio-ritualistic interpretations of the use of the rhyton within eighth-century CE Sogdiana. Through a close art-historical analysis, it argues that three eighth-century wall paintings from Panjikent illustrate a drinking game. This proposal expands the current breadth of meaning attributed to the imagery decorating Sogdian homes. Not only could the paintings illustrate epic narratives, religious veneration, or moral didacticism, but they could also celebrate conviviality, fun, and humor.
X-ray flat-panel detector geometry correction to improve dimensional computed tomography measurements
Authors: Lüthi Melina , Bircher Benjamin A , Meli Felix , Küng Alain , Thalmann Rudolf
Published: October 2019

To improve the accuracy of dimensional x-ray computed tomography (CT), error sources have to be characterised and accounted for. A variety of error sources have been comprehensively described in the literature. However, the influence of geometrical distortion of the flat-panel detector has rarely been considered. In this paper, the deviation from nominal geometry of a flat-panel x-ray detector was characterised using a calibrated ball plate. In-plane deviations were separated from the detector topography by varying the source–detector distance, resulting in a 3D detector geometry. A correction model for arbitrary source–detector distances was developed, which reduced the maximum errors of sphere centre-to-centre distances in scale-corrected CT measurements from  ±3.9 µm to below  ±0.8 µm. This fivefold improvement emphasises the importance of such correction for dimensional CT.
Single-electron transport through single and coupling dopant atoms in silicon junctionless nanowire transistor*
Authors: Zhang Xiao-Di , Han Wei-Hua , Liu Wen , Zhao Xiao-Song , Guo Yang-Yan , Yang Chong , Chen Jun-Dong , Yang Fu-Hua
Published: October 2019

We investigated single-electron tunneling through single and coupling dopant-induced quantum dots (QDs) in silicon junctionless nanowire transistor (JNT) by varying temperatures and bias voltages. We observed that two possible charge states of the isolated QD confined in the axis of the initial narrowest channel are successively occupied as the temperature increases above 30 K. The resonance states of the double single-electron peaks emerge below the Hubbard band, at which several subpeaks are clearly observed respectively in the double oscillated current peaks due to the coupling of the QDs in the atomic scale channel. The electric field of bias voltage between the source and the drain could remarkably enhance the tunneling possibility of the single-electron current and the coupling strength of several dopant atoms. This finding demonstrates that silicon JNTs are the promising potential candidates to realize the single dopant atom transistors operating at room temperature.
Influence of the feed per tooth variation on the surface roughness at end milling of an aluminum alloy
Authors: Pop A B , Țîțu A M
Published: October 2019

As a part of the cutting process, a researched aspect continuously is surface quality. Based on and using the results of previous research, the present scientific paper addresses the problem of the machined surfaces roughness. The cutting process approached in this study is the end-milling one, and the workpiece material used to carry out the study is the aluminum alloy used in the aerospace industry. The adopted cutting regime imply to keep the cutting speed at a constant value while the cutting parameters: cutting depth and feed per tooth vary with different values. The experimental research carried out by the authors in a prestigious industrial company is complicated and complies with the specific methodology. The conclusions stand based on the interpretation of the results obtained from the experiments which were carried out based on the active experimental type. The confirmation of the obtained results was performed using the profiles and images of the microscopic analysis of the machined surface.
Algorithms for modelling the load of teeth from pinion cutter tool used at worms machining
Authors: Bordeanu M , Frumusanu G , Oancea N
Published: October 2019

The turning of worms with tools of pinion cutter type means to generate helical surfaces by rolling. In this case, the process of detaching the chip by tool successive teeth is characterized by uneven variation of chip total area, calculated as sum of the areas corresponding to the chips simultaneously detached by all tool teeth in contact at a time with the machined part. As consequence, the cutting forces that load the tool cutting edges are also uneven which negatively impacts the machining process: uneven wear of tool teeth and uneven elastic deformation of technological system with bad effects onto the precision of generated worm flanks. This paper proposes the analytical modelling for both area and shape of the chips detached, during the machining process, by the successive teeth of the pinion cutter that generates a cylindrical worm. The tool tooth involute flanks and the arc from tooth head are modelled, thus delimiting the region formed by the successive active teeth of the tool. The model of the chip detached during the rolling between tool and part centrodes is determined and, on this base, the area of the chip detached for an increment of tool rotation is found. Starting from proposed model, a graphical application in CATIA environment was developed in order to calculate the cumulated area of chips simultaneously detached by tool teeth, which is further needed in order to reduce the cutting force unevenness.
Surface roughness at facing on a lathe
Authors: Beșliu I , Cîcu A , Beșliu E , Agrigoroae C , Coteață M
Published: October 2019

It is known that during the facing on a lathe, due to the cutting speed change along the workpiece radius, the generation of the built-up edge is possible. Because of this fact, a maximum of the surface asperities height could be highlighted. From the practical point of view, it is important to have information concerning the influence exerted by some input factors of the facing process on the values of the roughness parameters that corresponds to the surfaces obtained by such a machining process. An experimental research was designed and materialized to evaluate the influence exerted by the cutting speed, feed rate and turning tool corner radius on the values of the surface roughness parameters Ra and Rq. By mathematical processing of the experimental results, some empirical mathematical models were determined. One confirmed that a low value of the surface roughness could be obtained by using high turning speed and adequate values for the feed rate and turning tool corner radius.
Studies on the influence of design parameters on the behaviour at shock of 3D-printed components fabricated by fused deposition modelling
Authors: Anghel D C , Rizea A D , Iordache D M , Beșliu-Gherghescu M L
Published: October 2019

In the last years, more and more products are made through fused deposition modelling (FDM). Although it has the disadvantage that it is a slow process, it is very well suited for the parts with complex shapes, which are difficult to obtain by classical machining. A huge advantage of this process is that the internal structure of the piece can be personalized according to the operation requirements. In the FDM process, the parts are builds up layer by layer. 3D printed objects will often have anisotropic mechanical properties. This means a printed part will be weaker in the direction of the Z axis. This paper presents studies on the influence of design parameters on the behaviour at shock of 3D-printed components fabricated by FDM. For this purpose, test specimens for shock breakout were made. The specimens were made with various internal structures and different orientations. The material for the parts is ULTRAT.