bluuebunny/crossref_metadata_2025 huggingface dataset:
NELIOTA: Methods, statistics, and results for meteoroids impacting the Moon
Authors: Liakos A. , Bonanos A. Z. , Xilouris E. M. , Koschny D. , Bellas-Velidis I. , Boumis P. , Charmandaris V. , Dapergolas A. , Fytsilis A. , Maroussis A. , Moissl R.
Published: December 2019

Context. This paper contains results from the first 30 months of the NELIOTA project for near-Earth objects and meteoroids impacting the lunar surface. We present our analysis of the statistics concerning the efficiency of the campaign and the parameters of the projectiles and those of their impacts.

Aims. The parameters of the lunar impact flashes are based on simultaneous observations in two wavelength bands. They are used to estimate the distributions of the masses, sizes, and frequency of the impactors. These statistics can have applications in both space engineering and science.

Methods. The photometric fluxes of the flashes are measured using aperture photometry and their apparent magnitudes are calculated using standard stars. Assuming that the flashes follow a black body law of irradiation, the temperatures can be derived analytically, while the parameters of the projectiles are estimated using fair assumptions on their velocity and luminous efficiency of the impacts.

Results. There have been 79 lunar impact flashes observed with the 1.2 m Kryoneri telescope in Greece. The masses of the meteoroids range between 0.7 g and 8 kg, and their respective sizes between 1 and 20 cm, depending on their assumed density, impact velocity, and luminous efficiency. We find a strong correlation between the observed magnitudes of the flashes and the masses of the meteoroids. Moreover, an empirical relation between the emitted energies of each band has been derived, allowing for an estimation of the physical parameters of the meteoroids that produce low energy impact flashes.

Conclusions. The NELIOTA project has so far the highest detection rate and the faintest limiting magnitude for lunar impacts compared to other ongoing programs. Based on the impact frequency distribution on the Moon, we estimate that sporadic meteoroids with typical masses less than 100 g and sizes less than 5 cm enter the mesosphere of the Earth with a rate of ~108 meteoroids h−1 and also impact Moon with a rate of ~8 meteoroids h−1.
Research regarding the design and manufacturing of hand orthosis by using Fused Deposition Modeling technology
Authors: Păcurar Ancuţa , Rău Monica , Păcurar Răzvan , Guţiu Eugen , Bacali Laura , Cosma Cosmin
Published: December 2019

The article presents the designing of an orthosis used for immobilization of the hand after a surgical operation or bone fracture. Finite element analysis was used for the shape optimization of the orthosis, in close connection with constrains given by the mechanical resistance of the part and constrains given by the technological parameters used in the AM process. The orthosis was finally manufactured by Fused Deposition Modeling at the Technical University of Cluj-Napoca, the results could be implemented in the Romanian medical system.
The future of industry with collaborative robots
Authors: Matúšová Miriam , Bučányová Marcela , Hrušková Erika
Published: December 2019

Rapidly changing user requirements, improving of quality of life or increased safety at work are allarguments for introducing flexible automation that replaces strenuous or dangerous work. Industrial robots with adaptive directing are now deployed to most industries due to their large range of uses. Theirmain addition for manufacturing is to eliminate downtime of complete operating and manipulating production process, to make easier all particular operation in accordance with ergonomics. The paper describescomparing between conventional industrial robot and collaborative robot.
Effect of the Weight reduction of a Gear Wheel on Modal Characteristics
Authors: Monkova Katarina , Monka Peter , Tkac Jozef , Hricova Romana , Mandulak Dusan
Published: December 2019

The paper deals with the influence of gear weight reduction on its modal properties. The aim of thepaper is to use the simulation tools to introduce the dependence of natural frequencies on the change in the shape of the gear, which is reflected in the change in weight. At the beginning of the paper, the theory and experimental bases of vibration testing and analysis are introduced to understand the principles of modal parameter specification. Verification of the boundary conditions used in the simulation was performed using the experimental method and it is described in the next part of the article. Tests confirmed the consistency of the values achieved by both approaches. Thus, the same boundary conditions could be used to specify the dependence of natural frequencies on the change in the geometry ofthe gear (which is associated with weight reduction). Numerical analysis was performed by FEM analysisusing PTC Creo software. Experimental modal analysis was performed using a PULSE measurement system.
Calculating the efficiency indicators in implementing purchase processes
Authors: Prajová Vanessa , Homokyová Mária , Horvátová Martina
Published: December 2019

The aim of the paper is to create a theoretical and analytical basis for the topic of calculating the efficiency of the implementation of the purchasing process. This topic is the main subject of research and as the subject of research there are data on the cost of deployment and operation of Enterprise Resource Planning of the world's leading suppliers. The contribution is mainly in processing theoretical solutions of the problem based on study of available materials and designing various types of metrics for execution of purchasing processes.
Study of health and safety in the manufacturing industry using Pareto analysis
Authors: Mureșan Petru Iulian , Miloșan Ioan , Senchetru Dorin , Reit Adrian Nicolae , Machedon Teodor Pisu , Oancea Gheorghe
Published: December 2019

The present paper carries out a study on health and safety in the manufacturing industry. The health and safety is analyzed for industrial workers in Brasov county for the years 2017 and 2018. The analysis is based on data for work related accidents and the processing was made using the Pareto Analysis. By complying with the 80/20 rule, it can be focused on the analysis of the 20% of the causes of work accidents that account for 80% of the total work accidents analyzed. Finally, it is presented which actions that can be taken to reduce accidents based on the analysis of the specific stages. After applying the Pareto Analysis in the year 2018 are obtained satisfactory results compared to the year 2017, thus optimizing the performance of the industrial activity in terms of health and safety and improve Quality Assurance in Industrial Manufacturing.
New materials obtained by rubber recycling from industrial waste
Authors: GABRIAN Simona Sorina , GROZAV Sorin–Dumitru , CIUŞCĂ Gabriel Nicodim , CECLAN Vasile Adrian , TURCU Antoniu , LEGUTKO Stanislaw
Published: December 2019

Solid waste management is one of the major environmental concerns nowadays. The present study covers the use of rubber and recycled plastics as replacement aggregates in concrete. Replacing the sand with plastics or rubber the compressive and tensile strength of the concrete decreases.. It was found that the concrete obtained by replacing a proportion not exceeding 9% of aggregates in the concrete recipe by rubber, can be used as a substitute for normal concrete, for instance in the building industry. The use of these materials in concrete comes from the environmental constraints in the safe disposal of the products. Big attention is being focused on the environment and safeguarding of natural resources and recycling of wastes materials.
Multiaxial High Cycle Fretting Fatigue
Authors: Alexander Araújo José , Magalhães Juvenal Almeida Gabriel , Comes Castro Fábio , Araújo Cardoso Raphael
Published: December 2019

The aim of this work is to show that multiaxial fatigue can be successfully adpted to model fretting problems. For instance, the paper presents (i) the critical direction method, as an alternative to the critical plane concept, to model the crack initiation path under fretting conditions and (ii) studies on size effects considering the influence of incorporating fretting wear on the life estimation. A wide range of new data generated by a two actuators fretting fatigue rig considering Al 7050-T7451 and of Ti-6Al-4V aeronautical alloys is produced to validate these analyses. It is shown that, the development of appropriate tools and techniques to incorporate the particularities of the fretting phenomenon into the multiaxial fatigue problem allow an accurate estimate of the fretting fatigue resistance/life in the medium high cycle regime. Such tools and techniques can be extended to the design of other mechanical components under similar stress enviroments.
On the phase angle role in the shear response of ZK60 Mg alloys under multiaxial fatigue
Authors: Karparvarfard Seyyed Mohamad Hasan , Behravesh Seyed Behzad , Kumar Shaha Sugrib , Jahed Hamid
Published: December 2019

Proportional and non-proportional multiaxial fatigue tests are conducted on the closed-die forged ZK60 extrusion. The shear strain amplitude was kept constant at 0.5% for all the tests, while two different axial strain amplitudes of 0.4% and 0.7% were considered. At the higher strain amplitude (0.7%) significant difference was observed between the torque amplitudes of proportional and non-proportional tests, whereas the axial load amplitude responses remained the same regardless of the phase angle shifts. It is likely that as the phase angle changes from 0-90, the twin volume fraction at the peak shear strain decreases resulting in higher torque responses. On the other hand, at the lower strain amplitude, i.e. 0.4%, where twinning is not active, phase angle does not show any effect on the shear response. An energy-based fatigue model is employed that effectively explains the different damage contributions by the axial and torsional loadings at different strain amplitudes, and accurately predicts the proportional and non-proportional multiaxial fatigue lives.
Influence of multiaxial cyclic plastic loading on grain boundary misorientation profile in austenitic stainless steel
Authors: Dey Rima , Tarafder Soumitra , Sivaprasad S
Published: December 2019

304LN stainless was subjected to multiaxial loading employing different waveforms and load paths. The grain boundary misorientation profile so obtained post deformation was compared across loading conditions. It was found that the uniaxial and proportional conditions of loading result in more of twins, contrary to non-proportional loading conditions that resulted in substantially higher low angle grain boundaries. Also, under non-proportional loading the trapezoidal load path resulted in remarkably altered distribution of the grain boundaries compared to its contemporaries. Predominant martensitic transformation was found to be dominant mechanism of deformation for trapezoidal loading that also contributed to the altered misorientation profile.
The contrast of simplicity and accuracy in modeling multiaxial notch fatigue
Authors: Riess Christian , Obermayr Martin , Vormwald Michael
Published: December 2019

The fatigue assessment of notches under multiaxial and non-proportional service loading is challenging. Simple models (e.g. local strain approach based on normal stress and strain) are of poor quality for this general case of stress states and ductile material behavior. Advanced approaches show high accuracy, but require additional material testing and calibration. From an engineering point of view, deviations are tolerable to a certain extent. This contribution introduces two approaches for modeling multiaxial notch fatigue which are easy to apply. The first approach is an extension of the classical local strain approach. The second approach implements a simplified multiaxial notch approximation which enables the use of the extended short crack model in practical applications.

A large database with experiments on notched components under multiaxial stresses is set up and used to validate the proposed algorithms. Results show the eﬀectiveness of both approaches for ductile steels. Both approaches can be useful for engineers who are faced to multiaxial fatigue of notched components.
Development of Fatigue Testing System for in-situ Observation by AFM & SEM
Authors: Farokh Payam Amir , Payton Oliver , Mostafavi Mahmoud , Picco Loren , Moore Stacy , Martin Tomas , Warren A.D. , Knowles David
Published: December 2019

A three-point bend fatigue miniature stage for in-situ observation of fatigue microcrack initiation and growth behaviour by scanning electron microscopy (SEM) and atomic force microscopy (AFM) has been manufactured. Details of the stage design with finite element analysis of the stress profiles on loading are provided. The proposed stage facilitates study of the micro mechanisms of fatigue when used during SEM and AFM scanning of the sample surface. To demonstrate the applicability of the system, fatigue tests have been performed on annealed AISI Type 316 stainless steel. Surface topography images obtained by SEM and HS-AFM (High Speed AFM) are presented for comparison. The data can be used to validate crystal plasticity models which should then directly predict multiaxial behaviour without recourse to deformation rules such as equivalent stress or strain.
The use of a modified critical plane model to assess multiaxial fatigue of steels with nonmetallic inclusions
Authors: Machado Pedro Vinícius Sousa , Araújo Lucas Carneiro , Soares Marcos Venicius , Araújo José Alexander
Published: December 2019

The goal of this research is to investigate the detrimental effect of non-metallic inclusions on the fatigue strength of the AISI 4140 steel under multiaxial loading conditions. In order to do so, a multiaxial fatigue model based on the critical plane approach is coupled with Murakami’s √area model. The proposed adaptation is very easy to calibrate and can also account for the higher probability of existing a fatal small defect as the volume of stresses material increases. Experimental multiaxial fatigue data were generated and compared with the estimates provided by the adapted multiaxial fatigue model and with its original version. The errors found are not higher than 10%.
Fatigue strength of S355JC steel under harmonic and random bending-torsion loading by a tri-axis shaker: Preliminary experimental results
Authors: Zanellati Davide , Benasciutti Denis , Tovo Roberto
Published: December 2019

A new testing system for applying coupled/uncoupled bending-torsion loading in vibratory tests by a tri-axis shaker has been recently developed at the Department of Engineering of University of Ferrara. The system is composed of a cylindrical specimen with eccentric tip masses, excited by horizontal and/or vertical base accelerations. A special design of the gripping system for specimen constraint allows torsional and bending deformations to be produced and controlled independently, when vertical and horizontal base accelerations are applied simultaneously by the shaker. The values of accelerations and strains in the tested specimens can be monitored continuously. This paper presents a first set of experimental results under harmonic bending and torsion, and under narrow-band combined random loading. Estimations from two frequency-domain approaches are also discussed.
Evaluation of residual stresses in a tube-to-plate welded joint
Authors: Chiocca Andrea , Frendo Francesco , Bertini Leonardo
Published: December 2019

A deep understanding of the manufacturing process is needed in order to achieve safety and quality requirements for parts and components; to this regard, residual stresses play an important role in welded structures. Residual stresses are mainly caused by the extremely severe thermal cycle to which the welded metal and base material are subjected to during welding process and their knowledge leads to a better static and fatigue assessment of welded joints. This work deals with the study of residual stresses for a tube to plate T-joint, made of S355JR carbon steel. The work was carried out by both numerical simulations and experimental tests. The numerical simulations were performed by Ansys FE code through a structural-thermal full transient analysis to evaluate stress, strain and temperature in each node at each step of the simulation. The “birth and death” method was employed, together with temperature-dependent material properties.A2Danda3D simulation were performed, in order to evaluate possible diﬀerences due to the welding process. Numerical results were compared to some preliminary measurements obtained through an incremental cut made on the plate.
Complexity in the Kitchen
Authors: Foley Joseph T. , Puik Lindy , Puik Erik , Smith Joseph , Cochran David S.
Published: December 2019

Axiomatic Design and Complexity theory are often applied to highly complex and technological systems which provide educators with many engineering examples and case studies. The use of Axiomatic Design is applicable outside of these areas. However, there are not many examples outside of these areas. As a result, students often have trouble understanding the breadth and impact of Axiomatic Design’s application to problem-solving. One large complex system that is often overlooked is that of the kitchen. In this paper, we present different food-related preparation tasks that are inherently complex: cooking a turkey, baking an apple pie, reverse-engineering a recipe, and designing ecologically-minded food packaging while also discussing the impact of prepared food’s packaging approaches on the environment. The authors believe such examples demonstrate Axiomatic Design’s applicability in a new aspect that is approachable to a wide audience.
Formulation of an Agile Office Product: An Application of Axiomatic Design in Engineering
Authors: Spalding Christopher , Wei ZiXiao , Yarkov Anthony
Published: December 2019

Axiomatic Design was applied in an undergraduate student-led project which culminated in the creation of an agile ergonomic monitor stand, a solution designed to optimise the productivity and working conditions of the office environment. The customer domain was determined using a Mendelow’s Stakeholder Analysis followed by contextual inquiries and lead user interviews. These customer needs were organised into different levels via Maslow’s Hierarchy and redefined in terms of functional requirements. The functional requirements were decomposed and classified using the Kano Customer Satisfaction and Long Tail Models, and ultimately organised into a functional requirement tree. Design constraints were considered and listed, and the customer and functional domains were compared using a House of Quality. This allowed potential design paths to be devised with respect to the chosen functional requirements. The path involving the smart ergonomic stand was chosen from a number of potential products assessed against the functional requirements by listing the potential design parameters in a morphologicalmatrix. Concepts were designed by creating combinations of these design parameters, with their suitability being judged using the Independence Axiom. The physical form of the solution was inspired using biological sources. The final details of the design were chosen using the Information Axiom to determine their suitability in practical implementation allowing the final concept to be produced in a 3D CAD model.
Influence of the axial position of the external load on the mechanical behavior of the bolted lap joint with different materials
Authors: He Peng , Fan Zhiqiang , Yu Xiangyu , Liu Zhansheng
Published: December 2019

The axial mechanical behaviors of the bolted joint are a primary concern of the bolted joint structures. The axial load position has obvious influence on the axial mechanical behaviors of the bolted joint with different materials, while it can not be considered by the analytical method yet. The objective of this work is to fill this gap. With the pressure cone assumption, the axial resilience of the stress zones is derived, and the detailed formulation of the load introduction factor is proposed. The mechanical behavior of the bolted joint subjected to external axial load is formulated and compared with finite element analysis. Results show that the distance between load planes has apparent influence on the axial mechanical behaviors of the bolted joint. In particular for the bolted joint with different materials, the axial positions of the external load have obvious effect on the mechanical behavior. Comparisons with the finite element results indicate that with the proposed formulation of load introduction factor, the analytical formulations could predict the mechanical behavior of the bolted joint with different materials accurately. The proposed formulation of load introduction factor in this work could be an effective supplement of the heavy duty bolt design guideline.
Das menschliche „Gewebs“-Mikrobiom im metabolischen Syndrom: der „Leaky Gut“ Hypothese auf der Spur
Authors: Massier Lucas , Kovacs Peter
Published: December 2019

Durch die Veränderung der intestinalen Permeabilität können Faktoren wie das Mikrobiom, Ernährung oder Medikamentengabe Einfluss auf die Entwicklung von Parametern des metabolischen Syndroms nehmen. Dabei kommt es zu Veränderungen im parazellulären Raum, durch die ein Influx von bakteriellen Bestandteilen möglich wird. Adipositas und Diabetes sind zudem mit erhöhten Endotoxinspiegeln in der von Endotoxin, z. B. über den TLR4 Rezeptor bekannt sind, ist der genaue Beitrag zu Merkmalen des metabolischen Syndroms noch unklar. Klar ist aber, dass Entzündung und Insulinresistenz erhöht werden können. Auch die Frage nach einem „Gewebs“-Mikrobiom im metabolischen Syndrom kann aufgrund der Datenlage noch nicht eindeutig beantwortet werden, denn obwohl erste Daten bakterielle DNA im Fettgewebe zeigen, gibt es auch gegensätzliche Arbeiten. Ein „Leaky Gut“ ist ein mögliches Merkmal des metabolischen Syndroms, welches zu den beobachteten Phänotypen beiträgt und, u. a. durch die erhöhte Entzündung in einem negativen Feedbackloop die intestinale Permeabilität weiter erhöhen kann.
Adjuvante Therapie beim HER2-positiven Brustkrebs
Authors: Arnheim Katharina
Published: December 2019

In einer umfassenden genomischen Analyse der APHINITY-Studie beim frühen HER2-positiven Brustkrebs konnten mehrere Biomarker für eine günstige Prognose und den Benefit von Pertuzumab identifiziert werden.
Malignes Schleimhautmelanom
Authors: Krome Susanne
Published: December 2019

Die Immuntherapie des malignen Melanoms bedeutet einen Durchbruch mit einer signifikanten Verlängerung des progressionsfreien und Gesamtüberlebens. Das maligne Schleimhautmelanom ist selten, sodass die moderne Therapiestrategie bei diesem Subtyp bislang wenig untersucht ist. In einer asiatischen Phase-IB-Studie war die Kombination aus VEGF- und PD-1-Inhibition wirksam und hatte vertretbare unerwünschte Effekte.
Magnetic Resonance–Guided Prostate Ablation
Authors: Woodrum David A. , Kawashima Akira , Gorny Krzysztof R. , Mynderse Lance A.
Published: December 2019

In 2019, the American Cancer Society (ACS) estimates that 174,650 new cases of prostate cancer will be diagnosed and 31,620 will die due to the prostate cancer in the United States. Prostate cancer is often managed with aggressive curative intent standard therapies including radiotherapy or surgery. Regardless of how expertly done, these standard therapies often bring significant risk and morbidity to the patient's quality of life with potential impact on sexual, urinary, and bowel functions. Additionally, improved screening programs, using prostatic-specific antigen and transrectal ultrasound-guided systematic biopsy, have identified increasing numbers of low-risk, low-grade “localized” prostate cancer. The potential, localized, and indolent nature of many prostate cancers presents a difficult decision of when to intervene, especially within the context of the possible comorbidities of aggressive standard treatments. Active surveillance has been increasingly instituted to balance cancer control versus treatment side effects; however, many patients are not comfortable with this option. Although active debate continues on the suitability of either focal or regional therapy for the low- or intermediate-risk prostate cancer patients, no large consensus has been achieved on the adequate management approach. Some of the largest unresolved issues are prostate cancer multifocality, limitations of current biopsy strategies, suboptimal staging by accepted imaging modalities, less than robust prediction models for indolent prostate cancers, and safety and efficiency of the established curative therapies following focal therapy for prostate cancer. In spite of these restrictions, focal therapy continues to confront the current paradigm of therapy for low- and even intermediate-risk disease. It has been proposed that early detection and proper characterization may play a role in preventing the development of metastatic disease. There is level-1 evidence supporting detection and subsequent aggressive treatment of intermediate- and high-risk prostate cancer. Therefore, accurate assessment of cancer risk (i.e., grade and stage) using imaging and targeted biopsy is critical. Advances in prostate imaging with MRI and PET are changing the workup for these patients, and advances in MR-guided biopsy and therapy are propelling prostate treatment solutions forward faster than ever.
Guidelines for the Execution of True Spherical Osteotomies Using a Modified Dome Blade Design
Authors: Nikolaou Christos , Black Cameron , Ochoa Juan J. , Fitzpatrick Noel
Published: December 2019

Objectives The purpose of this study was to explore the trigonometric principles of the spherical osteotomy, establish guidelines for its application and test the guidelines on bone models using a new blade design. We propose a new rule of osteotomies incorporating the outlined geometric principles, and applicable to the use of spherical cuts in veterinary orthopaedic surgery.

Materials and Methods The trigonometric principles for the execution of neutral, closing and opening spherical osteotomies were explored in silico. A modification of the existing commercially available dome blade was designed and manufactured such that it facilitated the performance of spherical osteotomy with a minimized blade radius. A pilot study was performed whereby the modified dome blade was used to create spherical osteotomy in canine radial bone models. The surfaces of the osteotomy models were laser-scanned using a three-dimensional (3D) scanner; the resultant scans were imported into and analysed using a commercial 3D analysis software. The accuracy of osteotomy execution was measured as the distance between the targeted centre of osteotomy and the actual centre of osteotomy as found on the 3D scans.

Results By utilizing the geometric principles of spherical osteotomy, an accurate osteotomy position was achieved. The centre of the spherical cut performed on bone models was confirmed to be within 5% tolerance of the location as planned in silico demonstrating the accurate and relevant clinical application of geometric principles.

Clinical Significance The trigonometric guidelines for the execution of spherical osteotomy can be applied in a pre-clinical environment with accuracy. The new guidelines combined with the proposed new rule for spherical osteotomy utilizing the new blade design are translatable into clinical application, permitting the surgeon to accurately plan osteotomy application while mitigating the significant loss of bone-to-bone contact during correction of torsional deformities inherent in the principles of dome osteotomy use.
New-day statistical thinking: A bold proposal for a radical change in practices
Authors: van Witteloostuijn Arjen
Published: December 2019

In this commentary, I argue why we should stop engaging in null hypothesis statistical significance testing altogether. Artificial and misleading it may be, but we know how to play the p value threshold and null hypothesis-testing game. We feel secure; we love the certainty. The fly in the ointment is that the conventions have led to questionable research practices. Wasserstein, Schirm, & Lazar (Am Stat 73(sup1):1–19, 2019. 10.1080/00031305.2019.1583913) explain why, in their thought-provoking editorial introducing a special issue of The American Statistician: “As ‘statistical significance’ is used less, statistical thinking will be used more.” Perhaps we empirical researchers can together find a way to work ourselves out of the straitjacket that binds us.
The effect of electric-power substitution policy on the energy transformation in China: A system-dynamics approach
Authors: Wang Yongli , Zhang Yuanyuan , Yang Jiale , Zhang Fuli , Wang Shuo , Ma Yuze
Published: December 2019

Accurate forecasting of regional energy supply and demand is of great significance for exploring alternative energies and promoting a strategic energy transformation. To support this transformation in China, we predict the Chinese energy demand and explore connections between energy substitution and energy structure transformation. To study how the electric-power substitution (EPS) policy affects energy demand in China, we construct a dynamic management model based on the approach of system dynamics and implement it by using Vensim software. This model is used to simulate and assess how, under different scenarios, the EPS policy affects energy demand and CO2 emissions in China for the period 2015–2035. The simulation shows the indispensable role of the EPS policy in promoting the transformation of China's energy structure.
Lattice thermal conductivity of quartz at high pressure and temperature from the Boltzmann transport equation
Authors: Xiong Xue , Ragasa Eugene J. , Chernatynskiy Aleksandr , Tang Dawei , Phillpot Simon R.
Published: December 2019

The thermal conductivities along the basal and hexagonal directions of α-quartz silica, the low-temperature form of crystalline SiO2, are predicted from the solution of the Boltzmann transport equation combined with the van Beest, Kramer, and van Santen potential for the temperature up to 900 K and the pressure as high as 4 GPa. The thermal conductivities at atmospheric pressure, which show a negative and nonlinear dependence on temperature, are in reasonable agreement with the experimental data. The influence of pressure on thermal conductivity is positive and linear. The pressure (P) and temperature (T) dependences of the thermal conductivity (λ) in basal and hexagonal directions are fitted to a function of the form λ=(b+cP)Ta. The thermal conductivity, influenced by temperature and pressure, is analyzed based on phonon properties, including spectral thermal conductivity, dispersion relation, phonon density of states, phonon lifetime, and phonon probability density distribution function.
Characteristics of an axisymmetric magnetic oscillation closely related to L-H transition on experimental advanced superconducting tokamak (EAST)
Authors: Ye K. X. , Zhang T. , Xiang H. M. , Geng K. N. , Zhong F. B. , Wu M. F. , Wen F. , Li G. S. , Wang Y. M. , Huang J. , Shi T. H. , Liu H. Q. , Zhang S. B. , Gao X. ,   EAST Team
Published: December 2019

An axisymmetric magnetic oscillation (AMO) of 5–10 kHz in the L-mode plasma edge has been studied on an experimental advanced superconducting tokamak. The analysis shows that this oscillation only occurs at the plasma very close to the L-H transition. The structure of magnetic oscillation is axisymmetric (n = 0) toroidally and demonstrates an m = 2 standing wave in the poloidal direction. The density fluctuation of AMO measured by reflectometry at the midplane is nearly in phase, indicating that the AMO is not a radial traveling wave. The AMO shows an obvious modulation effect on the background magnetic/density fluctuation, and as a result, the edge density/density gradient and particle flux onto the divertor are also modulated by the AMO. The frequency scaling of the AMO is fm∝(∇ne/Ip2)−1. The bicoherence analyses show a strong nonlinear interaction between the AMO and the background turbulence, and other nonlinear interactions between the AMO and three other coherent fluctuations with frequencies (∼4, ∼11, and ∼15 kHz) are also found.
Learned emergence in selfish collective motion
Authors: Algar Shannon D. , Lymburn Thomas , Stemler Thomas , Small Michael , Jüngling Thomas
Published: December 2019

To understand the collective motion of many individuals, we often rely on agent-based models with rules that may be computationally complex and involved. For biologically inspired systems in particular, this raises questions about whether the imposed rules are necessarily an accurate reflection of what is being followed. The basic premise of updating one’s state according to some underlying motivation is well suited to the realm of reservoir computing; however, entire swarms of individuals are yet to be tasked with learning movement in this framework. This work focuses on the specific case of many selfish individuals simultaneously optimizing their domains in a manner conducive to reducing their personal risk of predation. Using an echo state network and data generated from the agent-based model, we show that, with an appropriate representation of input and output states, this selfish movement can be learned. This suggests that a more sophisticated neural network, such as a brain, could also learn this behavior and provides an avenue to further the search for realistic movement rules in systems of autonomous individuals.
Local conductivity of graphene oxide study by conductive atomic force microscope
Authors: Li Jun , Wu Jie , Huang Zongyu , Qi Xiang , Zhong Jianxin
Published: December 2019

In this paper, a Conductive Atomic Force Microscope was used to measure the current distribution image of monolayer graphene oxide (GO) and I/V curves of different types of points in current distribution. Graphene oxide (GO) was prepared by a modified Hummer’s method and deposited on highly oriented pyrolytic graphite. We gradually increase the voltage range and analyze the effect of different voltages on improving the local conductivity of graphene oxide. It has been found that there are several critical voltages, such as 0.8 V, 1.5 V, 2.2 V, and 3.2 V. There is no current when the voltage is lower than 0.8 V; if the voltage is 1.5–2.1 V, the conductivity of GO can be slightly improved, but if not, it will significantly change the structure of graphene oxide; if the voltage is 2.2–3.1 V, the conductivity of GO can be greatly improved, but it still exhibits semiconductor properties; when the voltage increases to 3.2 V, the local conductivity of GO changes, showing metallicity. It was concluded that the strong electric field strength caused by voltage destroys the bond between oxygen-containing functional groups and the graphene oxide skeleton, which is very advantageous for studying the conductivity of GO.
Self-assembled lamellar-type nanostructure in manganite spinel (Co,Mn,Fe)3O4
Authors: Horibe Y. , Ishimatsu M. , Takeyama S. , Mori S. , Kudo M. , Auchi M. , Tanaka M. , Murakami Y.
Published: December 2019

Distinct nanostructures in (Co,Mn,Fe)3O4 were investigated using X-ray diffraction techniques combined with transmission and scanning transmission electron microscopy, as well as energy dispersive X-ray spectroscopy. The size of the checkerboard nanostructure increased with annealing, followed by the appearance of lamellar nanostructures comprising different types of platelike nanodomains because of nanoscopic spinodal decomposition of Mn and Fe ions. Remarkable local strain relaxation at the nanoscale associated with the domain size is suggested to play an important role in the stabilization of these checkerboard and lamellar nanostructures.
Properties of quantum dots coupled to plasmons and optical cavities
Authors: Westmoreland Dana E. , McClelland Kevin P. , Perez Kaitlyn A. , Schwabacher James C. , Zhang Zhengyi , Weiss Emily A.
Published: December 2019

Quantum electrodynamics is rapidly finding a set of new applications in thresholdless lasing, photochemistry, and quantum entanglement due to the development of sophisticated patterning techniques to couple nanoscale photonic emitters with photonic and plasmonic cavities. Colloidal and epitaxial semiconductor nanocrystals or quantum dots (QDs) are promising candidates for emitters within these architectures but are dramatically less explored in this role than are molecular emitters. This perspective reviews the basic physics of emitter-cavity coupling in the weak-to-strong coupling regimes, describes common architectures for these systems, and lists possible applications (in particular, photochemistry), with a focus on the advantages and issues associated with using QDs as the emitters.
Numerical simulations of the effects of the level of nitrogen impurities in atmospheric helium Townsend discharge
Authors: Liu Fucheng , Guo Xue , Zhou Zhixiang , He Yafeng , Fan Weili
Published: December 2019

The influence of nitrogen impurities on the atmospheric pressure helium discharge in Townsend mode is investigated based on a 1D fluid model. The level of nitrogen impurities was varied in the range 0.1–10 000 ppm, in which the discharge exhibits three notable discharge modes, namely multipulse Townsend discharge, single-pulse Townsend discharge, and multipulse glow discharge with the increase in the impurity level. It is found that the influence of nitrogen impurities on helium discharge in the Townsend mode is entirely different from that in the glow mode; the discharge characteristics are different under different nitrogen contents. Under 1 ppm nitrogen content, both the breakdown voltage and discharge current remain unchanged. As the N2 content increases, the breakdown voltage still remains unchanged but the discharge current decreases. As the N2 content exceeds 350 ppm, the discharge transits from the Townsend mode into the glow mode, and the breakdown voltage decreases dramatically while the current density increases.
Lasing from reduced dimensional perovskite microplatelets: Fabry-Pérot or whispering-gallery-mode?
Authors: Li Qi , Li Chun , Shang Qiuyu , Zhao Liyun , Zhang Shuai , Gao Yan , Liu Xinfeng , Wang Xina , Zhang Qing
Published: December 2019

Cesium lead bromide (CsPbBr3) perovskite has attracted great attention recently for its potentials for next-generation green-color lasing devices owing to the relatively high structural stability and the high emission efficiency among the perovskite family. Herein, we explore the origins of cavity modes in CsPbBr3 microplatelets (MPs) lasers by using angle-resolved microphotoluminescence Fourier imaging technique, which is still controversial so far. In-plane Fabry–Pérot (F-P) mode lasing transition to whispering-gallery-mode (WGM) lasing is verified at room temperature, which mostly occurs in large MPs with edge length (L) over 13 μm. The F-P lasing is suppressed upon decreasing L or increasing excitation density, and the WGM lasing is predominant for all MPs at high excitation density. Furthermore, the parity and symmetry of in-plane F-P modes are classified. These results advance the fundamental understanding of lasing modes in planar microcavities as well as their applications in on-chip interconnection and quantum optics.
Excited states via coupled cluster theory without equation-of-motion methods: Seeking higher roots with application to doubly excited states and double core hole states
Authors: Lee Joonho , Small David W. , Head-Gordon Martin
Published: December 2019

In this work, we revisited the idea of using the coupled-cluster (CC) ground state formalism to target excited states. Our main focus was targeting doubly excited states and double core hole states. Typical equation-of-motion (EOM) approaches for obtaining these states struggle without higher-order excitations than doubles. We showed that by using a non-Aufbau determinant optimized via the maximum overlap method, the CC ground state solver can target higher energy states. Furthermore, just with singles and doubles (i.e., CCSD), we demonstrated that the accuracy of ΔCCSD and ΔCCSD(T) (triples) far surpasses that of EOM-CCSD for doubly excited states. The accuracy of ΔCCSD(T) is nearly exact for doubly excited states considered in this work. For double core hole states, we used an improved ansatz for greater numerical stability by freezing core hole orbitals. The improved methods, core valence separation (CVS)-ΔCCSD and CVS-ΔCCSD(T), were applied to the calculation of the double ionization potential of small molecules. Even without relativistic corrections, we observed qualitatively accurate results with CVS-ΔCCSD and CVS-ΔCCSD(T). Remaining challenges in ΔCC include the description of open-shell singlet excited states with the single-reference CC ground state formalism as well as excited states with genuine multireference character. The tools and intuition developed in this work may serve as a stepping stone toward directly targeting arbitrary excited states using ground state CC methods.
Gene therapy technique offers a more targeted approach for treatment of pulmonary edema
Authors: Johnson-Groh Mara
Published: December 2019

A gene therapy technique virus vectors to target response pathways could offer a more selective way to treat pulmonary edema.
Photodissociation dynamics of OCS at 207 nm:
S(1D2)+CO(X1Σ+)
product channel
Authors: Bai Xi-lin , Zhao Dong-feng , Chen Yang
Published: December 2019

By using the direct current slice velocity map imaging technique, the polarization experiment for S(1D2) product from the ultraviolet photodissociation of carbonyl sulfide at 207 nm was studied. The angular momentum polarization character of the photofragment S(1D2) was detected via two different resonance enhanced multiphoton ionization intermediate states, 1F3 and 1P1, and four different pump-probe laser polarization geometries. The angular distribution of the corresponding CO(X1Σ+) coproducts was extracted and analyzed using the molecular-frame polarization and the laboratory-frame anisotropy models. The observed total kinetic energy release spectrum indicates that there are three dissociation channels, corresponding to the low, medium, and high kinetic energy. The sources of the low and medium kinetic energy channels are consistent with those of bimodal translational energy distribution at longer photolysis wavelengths. The high kinetic energy channel is a new dissociation channel arising from the direct dissociation from the single repulsive A(21A′) state.
Coarse-grained free-energy simulations of conformational state transitions in an adenosine 5′-triphosphate-binding cassette exporter
Authors: Huang Yun , Xu Hao-chen , Liao Jie-lou
Published: December 2019

ATP-binding cassette exporters transport many substrates out of cellular membranes via alternating between inward-facing and outward-facing conformations. Despite extensive research efforts over the past decades, understanding of the molecular mechanism remains elusive. As these large-scale conformational movements are global and collective, we have previously performed extensive coarse-grained molecular dynamics simulations of the potential of mean force along the conformational transition pathway [J. Phys. Chem. B 119, 1295 (2015)]. However, the occluded conformational state, in which both the internal and external gate are closed, was not determined in the calculated free energy profile. In this work, we extend the above methods to the calculation of the free energy profile along the reaction coordinate, d1–d2, which are the COM distances between the two sides of the internal (d1) and the external gate (d2). The potential of mean force is thus obtained to identify the transition pathway, along which several outward-facing, inward-facing, and occluded state structures are predicted in good agreement with structural experiments. Our coarse-grained molecular dynamics free-energy simulations demonstrate that the internal gate is closed before the external gate is open during the inward-facing to outward-facing transition and vice versa during the inward-facing to outward-facing transition. Our results capture the unidirectional feature of substrate translocation via the exporter, which is functionally important in biology. This finding is different from the previous result, in which both the internal and external gates are open reported in an X-ray experiment [Proc. Natl. Acad. Sci. USA 104, 19005 (2007)]. Our study sheds light on the molecular mechanism of the state transitions in an ATP-binding cassette exporter.
Protein S-nitrosylation in plant abiotic stresses
Authors: Zhang Jing , Liao Weibiao
Published: December 2019

Plants are exposed to various environmental stresses that affect crop growth and production. During stress, various physiological and biochemical changes including the production of nitric oxide (NO), take place. It is clear that NO could work through either transcriptional or post-translational level. The redox-based post-translational modification S-nitrosylation – the covalent attachment of an NO moiety to a reactive cysteine thiol of a protein to form an S-nitrosothiol (SNO) – has attracted increasing attention in the regulation of abiotic stress signalling. So far, the relevance of S-nitrosylation of certain proteins has been investigated under abiotic stress. In this work, we focus on the current state of knowledge regarding S-nitrosylation in plants under abiotic stress, and provide a better understanding of the relevance of S-nitrosylation in plant response to abiotic stress.