bluuebunny/crossref_metadata_2025 huggingface dataset:
Considerations on the role of modernizing the road infrastructure in the prevention of road accidents
Authors: Deac Cristian , Tarnu Lucian
Published: August 2019

The realizing and improvement of road infrastructure, of modern road networks provides normal, safe and pleasant road traffic conditions and also help prevent road accidents. The road network, with its constructive characteristics, has to offer optimal conditions for the movement of vehicles, pedestrians and other categories of participants in the road traffic. Starting from the case study of a road sector with heavy road traffic, the current paper analyzes the increase in road safety in Romanian localities along European and national roads through the implementation of specific measures such as setting up sidewalks, installing New Jersey median barriers, expanding the road sectors with 2+1 lanes, replacing normal pedestrian crossings with elevated crossings or with pedestrian crossing with mid-road waiting areas etc.
Changes Required in Organizing the Creativity Management in Romanian Firms
Authors: Moraru Gina-Maria , Popa Daniela
Published: August 2019

Resource management – both as a discipline and as a practice – has always emphasized the efficiency of their use. Current business conditions imply a profound change in the relationship between tangible and intangible resources. Increasing the share of creativity in the resources of any company in recent years has led to an increase in the share of creativity management in the overall management of organizations. But the sustainable development of a business depends on the way in which management exercises its functions over all resources. Thus, the ways that management chooses to organize this inexhaustible resource that is creativity are essential for business development. Based on a research carried out in Romanian companies, the paper presents some essential aspects related to the organization of creativity management in these. Furthermore, the paper synthesizes the suggestions of managers and specialists of the respective organizations regarding the changes to be made in this field.
Lean university: applying the ECRS method to improve an administrative process
Authors: Bârsan Raluca Mihaela , Codrea Felicia-Mihaela
Published: August 2019

This paper presents a case study for an improvement method applied in “Lucian Blaga” University of Sibiu, Romania. The ECRS method has its roots in manufacturing, specifically in improvement processes. The novelty lies in applying this method in Higher Education. Considering the existing know-how in process improvements of the human resource from the University and the importance of quality in the organisation’s performance, this paper sought to focus on using one of the most important principles of lean manufacturing in the administrative sector. An observation form was designed in order to analyse the process and by using the ECRS method and brainstorming for ideas with key stakeholders, the time needed by final-year students in order to complete the “University check-out” form was reduced.
Managerial strategies of the personal values, used to improve engineers communication
Authors: Bratu Mihaela Laura , Cioca Lucian-Ionel
Published: August 2019

Every person can be described by his behavior in certain situations, but also by the motivation of his actions, a motivation that reflects the individual values. The set of values of each individual is reflected in the everyday tasks, the way of communication, the degree of success of his actions. The higher the values apply in a wider area of life, the higher the personal satisfaction of the individual. Personal values are the internal standards and, at the same time, the inner force that determines us to learn, work and live in a certain way. The paper presents a study of a group of 116 engineers from different fields who sought to identify personal values in order to improve communication at the workplace. It was used The Inventory of Personal Values that measured the analyzed variable. The findings of the research are that management strategies that value the practical and organizational spirit of engineers improve workplace communication, increase employee performance and improve their well-being.
An experimental study on the improvement of functionality of knitted composite for mattress
Authors: Dinu Milena , Coman Diana
Published: August 2019

The comfort and performance of textile products used as mattress covers is analyzed in terms of physical characteristics, so air permeability and whiteness are investigated for different knitted assemblies with different compositions. The knitted system analyzed consists of two knitted surfaces assembled by a filling thread, finally obtaining a consistent composite material. Several samples of different fibrous composition were tested, analyzing their behavior during future use. A connection has been experienced between permeability, thickness, and whiteness of composites knitted of cotton, bamboo, wool, viscose and polyester. Samples tested for air permeability were tested face up and face down, using Static Air Permeability Tester. The whiteness of the knitted samples was checked using the Reflection Spectrophotometer trough the method that defines white and yellow indices. Samples containing bamboo and wool blended polyester have higher yellow markings. Thus, it may be recommended that future composite mattress knitted fabrics be treated with anti-aging to extend the product life cycle, as well as other friction wear-related experiments.
Considerations on the optimization of natural gas deliveries by using automated control systems
Authors: Gligor Alina , Huidan Sorin-Alecu
Published: August 2019

The current paper aims at optimizing the natural gas deliveries from an underground storage by implementing automated control systems and fiscal measurement systems according to the harmonized European legislation in the area of metrology. In the first part, the authors have carried out an analysis regarding the state of the art at international level with regard to technical solutions for optimizing the deliveries of natural gas by means of a constriction element of a measurement panel. In the following, a software application was created for monitoring the parameters taken from the process gas chromatograph and transferring them to the flow computer by implementing software filters. The novelty element here is that it allows the trading of the nominated natural gas amount in a set period of time.
Practical realisation and experimental results of ultrasonic filters used in air filtration
Authors: Niţoi Dan , Apostolescu Zoia , Iacobescu Gabriel , Rontescu Corneliu
Published: August 2019

Article presents the researches performed in order to achieve an air filter based on the ultrasonic cavitation phenomenon. This filter can be used in purification of polluted air from the highly polluting processing technology of an industrial shop (paint shops, foundries, welding constructions, forging, etc.). Practical realization elements of ultrasonic filter based on cavitation phenomenon and experimental results are described and presented. Experimental researches have shown an increased efficiency of using this type of filter (retention of microparticles larger than 1.0 μm, smoke retention and increase of duration of filter operation more many years). Besides these, advantages of using ultrasounds in the pollutant air filtration and purification process and an ultrasonic filter designed are presented.
Open source solutions to improve the quality of sustainable forest management
Authors: Bratu Iulian Alexandru
Published: August 2019

Climate change is becoming more acute, including in terms of individual perception. Forest, as an ecosystem, has a special role to play in mitigating climate change, protecting the soil, water and air. There are forests of scientific interest, preservation of the Eco fund and forest Geno fund, as well as recreational forests, so that the ecological functions are fulfilled in the optimum. Also, alongside the social function, green energy generation is one of the main attributes of the forest. In addition to preserving biodiversity, the forestry administration has as objectives the provision of the necessary resources for the short, medium and long-term development of local communities. Forest management that harmoniously combines ecological, economic and social functions cannot be sustained, at least in the information age, without relying on information technology. This article aims to address the issue of information technology in the forest administration, identifying needs and providing viable, high quality, open source solutions.
Bio-Gaseous Fuels from Agricultural Waste Pyrolysis (Part I)
Authors: Ionescu Gabriela , Bulmau Cora , Mărculescu Cosmin
Published: August 2019

The study, presented in two parts, puts in discussion the experimental results of low and high temperature pyrolysis on agricultural residues using a tubular batch reactor. During the experiment, nitrogen was used both as reaction environment and gas products carrier. The work focusses mainly on the pyrolysis gas analytical composition resulted from the process. The first part of the research is dedicated to the effect of process low temperature on rape straw pyrolysis. The experiments were conducted at 300°C, 400°C and 500°C to observe the solid – gas transformation at relative low temperatures. The main results revealed that, by balancing the amount of the nitrogen, the rape straw pyrolysis gas distribution varies by average between: 72%-77% CO2, 22%-24% CO, 1%-4% H2. The density of the gas in the devolatilization stage varies by average between 1.6-1.7 kg/m3, while its higher heating value ranges from 4 MJ/Nm3 - 8 MJ/Nm3.
Critical analysis of localization of micro-hydropower plant in the superior basin of Argeş river
Authors: Delayat Mădălina , Lazăr Maria
Published: August 2019

The purpose of this work is to anticipate the most important consequences generated by the installation of a micro-hydropower plant on mountain rivers, on the main components of the environment, and also to identify and locate the potential disruptions caused by the implementation of these projects. In addition, the authors would like to clarify certain aspects regarding the changes brought to the natural setting, the extent to which they affect the components of the environment, the capacity of nature to withstand these micro-hydropower plants and to naturally or artificially recover after the project is put into operation. Another aim is to establish measures for limiting the modifications that appear in time due to the installation of the micro-hydropower plants in order to ensure the good functioning of the respective plants. The main anthropic factors, that represent the subject of the analysis, act synergically, thus making it difficult to understand the impact of this project on the environment, especially since nature recovers itself under certain circumstances.
A comparative analysis of risk assessment techniques from the risk management perspective
Authors: Barb Crina Maria , Fita Daniel Nicolae
Published: August 2019

During the last decade, a major concern for Romanian Occupational Health and Safety (OHS) professionals and scholars raised in relation to risk assessment methods and techniques. As well documented in literature, the risk assessment is the basic step in the occupational health and safety risk management process. Risk assessment can be achieved at different levels according to the purpose of the analysis, according to the information, data and resources available. The aim of this paper is to perform a critical – comparative analysis of various worldwide applied methods, in order to establish their feasibility for further studies in the field of electrical safety. The paper gives an accurate comparative presentation in quantitive and qualitative terms of deterministic, probabilistic and combined methods. Furthermore, a detailed description of failure mode, effects and criticality analysis (AMDEC) technique and a SWOT (Strength, Weakness, Opportunity and Threat) analysis is performed. Conclusions are drawn and recommendations made, targeting the applicability of investigated methods for electrical safety activities from the risk management perspective.
Sensitivity to ignition by electrostatic discharge of explosive dust / air
Authors: Gabor Dan , Ghicioi Emilian , Părăian Mihaela , Vătavu Niculina , Păun Florin Adrian , Popa Mihai
Published: August 2019

In industrial sectors that use, process, transport or store, substances such as combustible dusts could exist some workplaces with explosion hazard due to the possibility of dust/air explosive formation and ignition, both inside the installations and in the surrounding atmosphere. Methods and means of protection aim to prevent the development of explosive atmospheres, followed by preventing the occurrence of ignition sources and then limiting the effects of explosions. To assess the risk of ignition of the explosive atmosphere, there must be known first of all, the explosive atmosphere’s sensitivity to ignition by electrostatic discharge, respectively, the minimum ignition energy of the explosive mixture, afterwards being required an analysis on the possibilities of formation and discharge of electrostatic charge. For the most common combustible dusts, the minimum ignition energy is given, but for new types of flammable substances this parameter defining the sensitivity to ignition of the mixture by electrostatic discharges must be determined. The paper presents the results of research carried out in order to develop the methods and standards for determining the minimum ignition energy of the combustible dust / air mixture and of the methods for the assessment of the risk of ignition of the dust/air explosive atmosphere by electrostatic discharge.
The value of students’ feedback
Authors: Mag Alina Georgeta
Published: August 2019

Quality teaching is directly related with effective and high-quality feedback, and such arguments are well supported by the findings of recent studies. Feedback constitutes a central aspect of learning, yet has been largely neglected in research to date, particularly from the student’s point of view. This gap in practice has been picked up by the Department for Teacher Training of “Lucian Blaga” University of Sibiu. This paper explores students’ perception of feedback. First year students enrolled at the Primary and Preschool Pedagogy program were invited to attend focus groups and individual interviews. A questionnaire was developed from themes identified in the focus groups and was administrated to a large group of undergraduate students in the second part of the study. This paper reports on the focus groups and the themes that emerged from the data. Findings revealed that receiving late and minimal feedback during the semester was a common cause of students’ dissatisfaction. Responses were mixed to the question of whether enough feedback was being provided. They indicated they wanted a more proactive approach from the academic staff, because they recognized the value of feedback as central to improved learning.
TecHUB 4.0 - Technology and Entrepreneurship Education for Bridging the Gap in Smart Product Development
Authors: Ulmeanu Mihaela , Doicin Cristian , Roșca Liviu , Rennie Allan , Abram Tom , Bajdor Paula
Published: August 2019

Additive manufacturing is a worldwide trend and has been successfully adopted in a wide variety of domains. With applications ranging from automotive, aerospace, military, consumer goods bioprinting and even wearable electronics, the need for trained workforce in additive manufacturing is in high demand. Academia all around the world is adapting to this new trend trying to develop new strategies in delivering suitable competences to their undergraduate, masters’ and PhD students. Such an initiative is the Erasmus+ project TecHUB 4.0 which brings together four complementary universities from Romania, United Kingdom and Poland. The main goal of the project is to bring together professors, industry specialists, researchers, managers, and entrepreneurs to deliver, using methods based on modern teaching technologies, especially on the use of web-based platforms and digital technologies – e-learning and interactive platforms, their knowledge to the young students wishing to become entrepreneurs in the additive manufacturing area. An Open Interactive Platform will be designed to be used equally by companies, by universities and by students, which will aggregate the demand and offer for internships developed in the scope of developing projects anchored in the day-to-day additive manufacturing business activity to solve concrete problems, but at the same time respecting all the economic constraints imposed on a business at beginning of its life.
Postoperatives Ergebnis bei Diskopathien des Hundes in
Abhängigkeit von Rasse, Lokalisation und Erfahrung des Chirurgen: 1113
Fälle
Authors: Klesty Alexandra , Forterre Franck , Bolln Gudrun
Published: August 2019

Gegenstand und Ziel Der Bandscheibenvorfall (BSV) ist eine häufige
neurologische Erkrankung bei Hunden, der in vielen Fällen chirurgisch behandelt
werden kann. Retrospektiv sollten bei solchen Patienten mögliche
Einflussfaktoren wie Signalement, Lokalisation oder Schweregrad des BSV sowie
Erfahrung des Operateurs auf das langfristige Behandlungsergebnis eruiert
werden.

Material und Methoden Die Auswertung umfasste die Daten von 1113 Hunden,
die von Januar 2008 bis Juli 2013 an einem oder mehreren Bandscheibenvorfällen
operiert worden waren.

Ergebnisse Hunde chondrodystropher (CD) Rassen mit einer Disposition wie
Dackel, Jack Russell Terrier und Französische Bulldogge erkrankten deutlich
früher an BSV als Hunde nicht chondrodystropher (NCD) Rassen mit signifikanten
rassespezifischen Unterschieden hinsichtlich Lokalisation und neurologischem
Schweregrad. Intakte Rüden waren überproportional häufiger betroffen, während
das Gewicht der Patienten nicht mit dem Auftreten eines BSV korrelierte. Der
neurologische Schweregrad und die Lokalisation des BSV, nicht aber die
Hunderasse oder der Erfahrungsgrad des Operateurs beeinflussten das
postoperative Behandlungsergebnis.

Schlussfolgerung und klinische Relevanz CD-Rassen erkrankten häufiger an
einem BSV als NCD-Rassen mit Französischen Bulldoggen als jüngsten Patienten.
Die meisten Vorfälle traten in der BWS (Peak in Th12/13) auf, die wenigsten in
der HWS mit rassespezifischen Unterschieden: Beagle erkrankten vorwiegend in der
HWS, Hunde kleiner NCD-Rassen, Dackel und Jack Russell Terrier in der BWS und
Französische Bulldoggen sowie Hunde großer NCD-Rassen in der LWS. Ungünstig für
das klinische Behandlungsresultat waren ein höherer neurologischer Schweregrad
und ein BSV in der BWS: Kleine NCD mit BSV Grad IV in der BWS hatten die längste
Rekonvaleszenz, während Französische Bulldoggen mit dem selben Grad in der LWS
schneller wieder lauffähig waren.
The use of a salmonella bacteriophage in bearded dragons:
application, passage time and reisolation
Authors: Renfert Kevin , Rabsch Wolfgang , Fruth Angelika , Speck Stephanie , Pees Michael
Published: August 2019

Objective This study determined the passage time and phage propagation
time of a salmonella specific phage, Felix O1, in bearded dragons, based on
reisolation from cloacal swabs and faecal samples following oral administration,
as a possible tool for reducing the zoonotic risk of salmonella from pet
reptiles. An application scheme for this phage in bearded dragons was
developed.

Material and methods Ten healthy bearded dragons (Pogona vitticeps)
were used in the study. The pH tolerance of the phage was tested and drugs were
used to evaluate their influence on the gastric pH of the reptiles. After pH
adjustment, the phage was administered orally for 12 consecutive days. Over
60 days, swabs were taken from the cloaca and examined for the presence of
phages using culture and PCR. Furthermore, faecal samples were collected for
phage quantification.

Results Felix O1 displayed no activity at pH below 2.8. A calcium- and
magnesium carbonate buffer induced an appropriate gastric pH increase for
30 minutes. Phages were reisolated for up to 24 days (mean shedding: 19 days)
after last administration. Titres between 105 and 107
plaque forming units/g faeces were detected. The animals did not show any
clinical signs related to phage application.

Conclusion and clinical relevance The study provides first results on oral
administration, passage time, and reisolation of a phage in reptiles. It could
be shown that the phage was able to replicate in the intestine, and was shed for
a prolonged period and therefore could potentially contribute to a reduction of
salmonella shedding.
Femoral Cementation in Knee Arthroplasty—A Comparison of Three Cementing Techniques in a Sawbone Model Using the ATTUNE Knee
Authors: Schwarze M. , Schonhoff M. , Beckmann N. A. , Eckert J. A. , Bitsch R. G. , Jäger S.
Published: August 2019

Femoral component loosening is a rare but severe complication in total knee arthroplasty. Former studies have repeatedly demonstrated radiolucent lines behind the ventral and dorsal anchoring shields of the femoral components, which has led us to investigate this matter further. Therefore, three different cementing techniques were tested in a group of nine Sawbone samples each. These differed in the amount of cement applied on the femoral component as well as in the pressure application. Computed tomography was performed to evaluate and classify the cement penetration into the bone adjacent to the prosthesis according to the zones defined by the Knee Society scoring system. The results show significantly deeper cement penetration in all zones when a pressurizer is used. In the other two groups, no significant difference in the dorsal bevel cement penetration was noted. Additionally, no difference in ventral and dorsal cement penetrations (Zones 1 and 4) was delineated. In contrast, there was a significant difference in both the ventral bevel (Zone 2) as well as the distal anchoring surface (Zones 5–7). The use of a pressurizer results in greater cement penetration into all anchoring areas. Completely covering the component back surface results in a significantly higher penetration, which is mainly due to differences in volume. These data show significantly improved cementation results when using a pressurizer. Whether this improves the biomechanical properties and ultimately the revision rate requires further investigation.
Obesity and Meniscal Transplant Failure: A Retrospective Cohort Study
Authors: Jiménez-Garrido Carlos , Gómez-Cáceres Abel , Espejo-Reina María Josefa , Espejo-Reina Alejandro , Tamimi Iskandar , Serrano-Fernández José Miguel , Dalla Rosa-Nogales Jaime , Espejo-Baena Alejandro
Published: August 2019

The purpose of this study was to analyze the effect of obesity and other clinical factors on the outcome of meniscal allograft transplantation (MAT) with transosseous fixation. A retrospective cohort study was performed on patients who underwent a MAT between 2002 and 2017. All the participants had a minimum follow-up period of 24 months. The variables assessed were age at the time of the transplant, side, sex, transplanted meniscus (lateral/medial), body mass index (BMI), smoking status, and previous surgeries. Lysholm, Tegner, and International Knee Documentation Committee (IKDC) test outcomes, and patient satisfaction were recorded. Image assessment was performed using plain standing X-rays and a follow-up magnetic resonance imaging scan. Thirty-five patients fulfilled the inclusion criteria. The mean follow-up time was of 75.7 standard deviation (SD) 43.4 months. Patients with a BMI ≥ 30 underwent medial meniscal transplants (88.9 vs. 42.3%, p = 0.022, respectively) more frequently. Obese patients had a significantly lower IKDC (48.6 SD 19.9 vs. 61.7 SD 13.1, p = 0.038, power: 57.5%) and Lysholm (60.3 SD 19.2 vs. 79.4 SD 14.3, p = 0.004, power: 88.7%) scores compared with nonobese patients. The satisfaction and Tegner scores were also lower in obese patients (55.6 vs. 80.7%, p = 0.136, and 2.8 SD 1.0 vs. 4.0 SD 1.9, p = 0.104, respectively); however, these differences were not statistically significant. Obese patients had higher rates of meniscal transplant failure compared with nonobese patients (adjusted hazard ratio: 11.8 [95% confidence interval: 1.5–91.4]). No differences were observed between obese and nonobese patients regarding age, sex, side, smoking status, and follow-up time. In this study, a BMI ≥ 30 kg/m2 resulted in higher MAT failure rates. Nonobese patients had better knee functional results compared with obese individuals.
Application of quantum-statistical methods to studies of thermodynamic and radiative processes in hot dense plasmas
Authors: Orlov Nikolay Yu. , Kadatskiy Maxim A. , Denisov Oleg B. , Khishchenko Konstantin V.
Published: August 2019

Calculations of thermodynamic and radiative characteristics of hot dense plasmas within different quantum-statistical approaches, such as the use of the Hartree–Fock–Slater model and the ion model, are presented. Calculated equations of state of different substances are used to investigate findings from absolute and relative measurements of the compressibility of solid aluminum samples in strong shock waves. It is shown that our calculated Hugoniot adiabat of aluminum is in a good agreement with experimental data and other theoretical results from first principles. We also present a review of the most important applications of the quantum-statistical approach to the study of radiative properties of hot dense plasmas. It includes the optimization problem of hohlraum wall materials for laser inertial fusion, calculations of the radiative efficiency of complex materials for optically thin plasma in X-pinch, modeling of radiative and gas-dynamic processes in plasma for experiments, where both intense laser and heavy ion beams are used, and temperature diagnostics for X- and Z-pinch plasmas.
Controlling the nucleation and annihilation of skyrmions with magnetostatic interactions
Authors: Vidal-Silva N. , Riveros A. , Tejo F. , Escrig J. , Altbir D.
Published: August 2019

Skyrmions have become one of the most visited topics during the last decade in condensed matter physics. In this work, and by means of analytical calculations and micromagnetic simulations, we explore the effect of the magnetostatic field generated by a magnetic tip on the stability of skyrmions. Our results show that the interaction energy between the tip and the skyrmion plays a fundamental role in the stabilization of Néel skyrmions confined in nanodisks, allowing its nucleation and annihilation and also providing precise control of its size and polarity. Based on our results, we propose a very simple and cyclic method to nucleate and annihilate skyrmions, as well as to control their polarity and chirality. This proposal could open possibilities for logic devices taking advantage of all the degrees of freedom that skyrmionic textures have.
Revealing the formation dynamics of the electric double layer by means of in-situ Rutherford backscattering spectrometry
Authors: Khojasteh Nasrin B. , Apelt Sabine , Bergmann Ute , Facsko Stefan , Heller René
Published: August 2019

We report on a new versatile experimental setup for in situ Rutherford backscattering spectrometry at solid-liquid interfaces which enables investigations of electric double layers directly and in a quantitative manner. A liquid cell with a three-electrode arrangement is mounted in front of the beam line, and a thin Si3N4 window (thickness down to 150 nm) separates the vacuum of the detector chamber from the electrolyte in the cell. By minimizing the contribution of the window to the measurement, a large variety of elements at the solid-liquid interface with sensitivities far below one monolayer can be monitored. The attachment of Ba onto the Si3N4 surface as a function of contact time and pH value of the electrolyte solution was chosen as an example system. From our measurement, we can not only follow the evolution of the double layer but also derive limits for the point of zero charge for the Si3N4 surface. Our findings of 5.7≤pHPZC≤6.2 are in good agreement with values found in the literature obtained by other techniques. Despite focusing on a specific system in this work, the presented setup allows for a large variety of in situ investigations at solid-liquid interfaces such as, but not limited to, tracing electrochemical reactions and monitoring segregation, adsorption, and dissolution and corrosion processes.
Design of a containment apparatus for synchrotron XAS measurements of radioactive fluid samples under high temperatures and pressures
Authors: Dhakal Diwash , Mayanovic Robert A. , Baker Jason L. , Boukhalfa Hakim , Xu Hongwu , Sun Cheng-Jun
Published: August 2019

The simple working principles and versatility of the hydrothermal diamond-anvil cell (HDAC) make it highly useful for synchrotron x-ray studies of aqueous and fluid samples at high pressure-temperature (P-T) conditions. However, safety concerns need to be overcome in order to use the HDAC for synchrotron studies of aqueous radioactive samples at high temperatures and pressures. For accomplishment of such hydrothermal experiments of radioactive materials at synchrotron beamlines, the samples are required to be enclosed in a containment system employing three independent layers of airtight sealing at some synchrotron facilities while enabling access to the sample using several experimental probes, including incoming and outgoing x-rays. In this article, we report the design and implementation of a complete radiological safety enclosure system for an HDAC specialized for high P-T x-ray absorption spectroscopy (XAS) measurements of aqueous solutions containing the actinides at synchrotron beamlines. The enclosure system was successfully tested for XAS experiments using the HDAC with aqueous samples containing depleted uranium at temperatures ranging from 25 to 500 °C and pressures ranging from vapor pressure to 350 MPa.
Work function modulation of electrodes contacted to molybdenum disulfide using an attached metal pad
Authors: Shimazu Yoshihiro , Iwabuchi Tatsuya , Arai Kensuke
Published: August 2019

The transport properties of electronic devices fabricated using two-dimensional materials are severely affected by the Schottky barrier at the contact of an electrode. The Schottky barrier height exhibits a strong correlation with the work function of the electrode. We observed rectifying current–voltage characteristics for a back-gated field effect transistor with a channel of molybdenum disulfide and Al electrodes, where one of the electrodes is attached to a Au pad. This result is explained in terms of the increase in the effective work function of the Al electrode attached to the Au pad. The dependence of a photocurrent on the bias voltage exhibited an opposite tendency to the current–voltage characteristics; this is also attributed to the work function modulation of the electrode, thus resulting in the variation in the Schottky barrier height.
Longitudinal electrostatic waves in isotropic thermal plasmas: Ultrarelativistic pair plasmas
Authors: Touil B. , Schlickeiser R. , Bendib A.
Published: August 2019

The dispersion relation of longitudinal electrostatic waves in unmagnetized isotropic thermal plasmas is investigated in the collisionless limit using fully relativistic kinetic plasma theory. Specifically, an electron-positron plasma is studied in the limits of nonrelativistic and ultrarelativistic plasma temperatures. In the limit of nonrelativistic plasma temperatures, the earlier dispersion relation, based on nonrelativistic dispersion theory, is reproduced. In the limit of ultrarelativistic plasma temperatures, we analyze analytically and numerically the dispersion relation of the longitudinal electrostatic mode which occurs in the subluminal and superluminal frequency regime. We correct some earlier results in the literature on the subluminal dispersion relation.
Non-leaky longitudinal acoustic modes in ScxAl1-xN/sapphire structure for high-temperature sensor applications
Authors: Aubert Thierry , Naumenko Natalya , Bartoli Florian , Pigeat Philippe , Streque Jérémy , Ghanbaja Jaafar , Elmazria Omar
Published: August 2019

Multilayered structures based on wide bandgap nitride piezoelectric thin films are very attractive for high-temperature surface acoustic wave (SAW) sensor applications. In this respect, scandium aluminum nitride (ScAlN) films are of particular interest as they combine enhanced piezoelectric properties and slower acoustic wave velocities when the Sc content steadily increases up to 40%. This property offers the possibility to combine slow ScAlN films on fast substrates like sapphire, to generate higher-order SAW modes which often show a better electromechanical coupling coefficient k2 compared to zero-order modes. In this letter, we show that low-attenuated longitudinal SAW can be generated in the ScxAl1-xN/sapphire structure, for the x parameter varying in a large range. This theoretical result is then confirmed by the experimental investigation of SAW resonators based on highly textured (002) Sc0.09Al0.91N films sputtered on c-cut sapphire substrates. It is finally shown that the use of electrodes based on metals with high density can lead to SAW structures offering a unique combination between a large bandgap over 5 eV, a k2 value beyond 1%, and a high SAW velocity near 10 000 m/s.
Electromagnetic induction imaging with atomic magnetometers: Unlocking the low-conductivity regime
Authors: Marmugi Luca , Deans Cameron , Renzoni Ferruccio
Published: August 2019

Electromagnetic induction imaging with atomic magnetometers has disclosed unprecedented domains for imaging, from security screening to material characterization. However, applications to low-conductivity specimens—most notably for biomedical imaging—require sensitivity, stability, and tunability only speculated thus far. Here, we demonstrate contactless and noninvasive imaging down to 50 S m−1 using a 50 fT/Hz 87Rb radio frequency atomic magnetometer operating in an unshielded environment and near room temperature. Two-dimensional images of test objects are obtained with a near-resonant imaging approach, which reduces the phase noise by a factor 172, with a projected sensitivity of 1 S m−1. Our results, an improvement of more than three orders of magnitude on previous imaging demonstrations, push electromagnetic imaging with atomic magnetometers to regions of interest for semiconductors, insulators, and biological tissues.
Low temperature growth of Ga2O3 films on sapphire substrates by plasma assisted pulsed laser deposition
Authors: Hu Congyu , Zhang Fabi , Saito Katsuhiko , Tanaka Tooru , Guo Qixin
Published: August 2019

Monoclinic β-Ga2O3 thin films with (-201) orientation have been fabricated at substrate temperature as low as 200 °C by using plasma assisted pulsed laser deposition. The film showed high transmittance of over 80% with clear fringes in the wavelength range from 300 to 1000 nm. Structural characterization from X-ray diffraction as well as Raman spectra analysis demonstrated the monoclinic structure of the films. β-Ga2O3 film deposited at 200 °C showed similar growth rate as well as optical bandgap values with films grown at higher temperatures from 300 to 500 °C, indicating the enhanced reaction between Ga and oxygen species during the deposition process with the assistant of plasma at low temperature. The low temperature growth of β-Ga2O3 film paves the way to be compatible with the established lithography of semiconductor microfabrication processes.
Lattice deformation on flat-band modulation in 3D Hopf-linked carbon allotrope: Hopfene
Authors: Tomita Isao , Saito Shinichi
Published: August 2019

Flat bands form in a 3D Hopf-linked graphene crystal or a 3D carbon allotrope named Hopfene, which qualitatively differ from bands of only graphenes. This paper discusses carbon-hexagon deformation on the level shift of a flat band via density-functional-theoretical (DFT) analysis to set the flatband level to the Fermi level, viz., to utilize its large density of states for magnetic- and electronic-property research. Tight-binding (TB) analysis is also performed for a comparison with the DFT analysis; here, a qualitative agreement between TB and DFT bands is obtained. The DFT analysis shows an almost linear flatband level shift to the lattice-deformation rate, where electron-interaction effects are included within the Kohn-Sham method. To tune the flatband level so that it fits the Fermi level, a double-heterolike structure is also proposed as a way of hexagon-deformation control.
Claudin-9 structures reveal mechanism for toxin-induced gut barrier breakdown
Authors: Vecchio Alex J. , Stroud Robert M.
Published: August 2019

The human pathogenic bacterium
Clostridium perfringens
secretes an enterotoxin (CpE) that targets claudins through its C-terminal receptor-binding domain (cCpE). Isoform-specific binding by CpE causes dissociation of claudins and tight junctions (TJs), resulting in cytotoxicity and breakdown of the gut epithelial barrier. Here, we present crystal structures of human claudin-9 (hCLDN-9) in complex with cCpE at 3.2 and 3.3 Å. We show that hCLDN-9 is a high-affinity CpE receptor and that hCLDN-9–expressing cells undergo cell death when treated with CpE but not cCpE, which lacks its cytotoxic domain. Structures reveal cCpE-induced alterations to 2 epitopes known to enable claudin self-assembly and expose high-affinity interactions between hCLDN-9 and cCpE that explain isoform-specific recognition. These findings elucidate the molecular bases for hCLDN-9 selective ion permeability and binding by CpE, and provide mechanisms for how CpE disrupts gut homeostasis by dissociating claudins and TJs to affect epithelial adhesion and intercellular transport.
Estimating time‐to‐contact with temporal occlusion in relay swimming: a pilot study
Authors: Ribeiro Lilian , Costa Aldo M. , Louro Hugo , Sobreiro Pedro , Esteves Pedro , Conceição Ana
Published: August 2019

The purpose of this study was to analyse swimmers’ perceptual judgements of a simulated time‐to‐contact task in freestyle swimming relays.

The study sample consisted of 31 national‐level swimmers of both genders (n = 18 males, 17.22 ± 1.95 yrs.; n = 13 females, 14.61 ± .76 yrs.). Participants were asked to watch two videos corresponding to the last course of a given swimmer during a competition of 4 × 100 m and 4 × 200 m freestyle events. These videos were presented with temporal occlusion correspondent to predetermined approaching distances (7.5, 5.0, and 2.5 m). Participants were required to simulate a typical position in standby for exiting the block and estimate the time‐to‐contact of the incoming swimmer by pressing a switch. A Wilcoxon test was performed to determine differences between time‐to‐contact and real contact time.

The results showed that estimation of time‐to‐contact was generally lower than real contact time at all approaching distances (with occlusion) and for both genders (p < .05), except at a 7.5‐m distance in the men's 4 × 200 m (p = .744; r = .09) and at 5.0 m in both the 4 × 100 m and 4 × 200 m for the female group (p = .279, r = .22 for 4 × 100 m; p = .2453, r = .17 for 4 × 200 m). The larger variation (Δ) between estimation and real contact time was found at a 7.5 m occlusion distance in the female 4 × 100 m (p < .001; r = .82).

Swimmers tend to underestimate the time‐to‐contact of the incoming swimmer, in the context of a simulated relay race. Taken together, these results highlight the importance of perceptual abilities development in swimmers to optimize their technique and effectiveness during relay starts.
Brownian molecules formed by delayed harmonic interactions
Authors: Geiss Daniel , Kroy Klaus , Holubec Viktor
Published: August 2019

A time-delayed response of individual living organisms to information exchanged within flocks or swarms leads to the emergence of complex collective behaviors. A recent experimental setup by (Khadka et al 2018 Nat. Commun.
9 3864), employing synthetic microswimmers, allows to emulate and study such behavior in a controlled way, in the lab. Motivated by these experiments, we study a system of N Brownian particles interacting via a retarded harmonic interaction. For

N
≤
3

, we characterize its collective behavior analytically, by solving the pertinent stochastic delay-differential equations, and for N > 3 by Brownian dynamics simulations. The particles form molecule-like non-equilibrium structures which become unstable with increasing number of particles, delay time, and interaction strength. We evaluate the entropy and information fluxes maintaining these structures and, to quantitatively characterize their stability, develop an approximate time-dependent transition-state theory to characterize transitions between different isomers of the molecules. For completeness, we include a comprehensive discussion of the analytical solution procedure for systems of linear stochastic delay differential equations in finite dimension, and new results for covariance and time-correlation matrices.
Topological magnon insulator and quantized pumps from strongly-interacting bosons in optical superlattices
Authors: Mei Feng , Chen Gang , Goldman N , Xiao Liantuan , Jia Suotang
Published: August 2019

Wepropose a scheme realizing topological insulators and quantized pumps for magnon excitations, based on strongly-interacting two-component ultracold atoms trapped in optical superlattices. Specifically, we show how to engineer the Su–Schrieffer–Heeger model for magnons using state-independent superlattices, and the Rice-Mele model using state-dependent superlattices. We describe realistic experimental protocols to detect the topological signatures of magnon excitations in these two models. In particular, we show that the non-equilibrium dynamics of a single magnon can be exploited to directly detect topological winding numbers and phase transitions. We also describe how topological (quantized) pumps can be realized with magnons, and study how this phenomenon depends on the initial magnon state preparation. Our study opens a new avenue for exploring magnonic topological phases of matter and their potential applications in the context of topological magnon transport.
Realistic sub-Rayleigh imaging with phase-sensitive measurements
Authors: Bonsma-Fisher Kent A G , Tham Weng-Kian , Ferretti Hugo , Steinberg Aephraim M
Published: August 2019

As the separation between two emitters is decreased below the Rayleigh limit, the information that can be gained about their separation using traditional imaging techniques, photon counting in the image plane, reduces to nil. Assuming the sources are of equal intensity, Rayleigh’s ‘curse’ can be alleviated by making phase-sensitive measurements in the image plane. However, with unequal and unknown intensities the curse returns regardless of the measurement, though the ideal scheme would still outperform image plane counting (IPC), i.e. recording intensities on a screen. We analyze the limits of the super-resolved position localization by inversion of coherence along an edge (SPLICE) phase measurement scheme as the intensity imbalance between the emitters grows. We find that SPLICE still outperforms IPC for moderately disparate intensities. For larger intensity imbalances we propose a hybrid of IPC and SPLICE, which we call ‘adapted SPLICE’, requiring only simple modifications. Using Monte Carlo simulation, we identify regions (emitter brightness, separation, intensity imbalance) where it is advantageous to use SPLICE over IPC, and when to switch to the adapted SPLICE measurement. We find that adapted SPLICE can outperform IPC for large intensity imbalances, e.g. 10 000:1, with the advantage growing with greater disparity between the two intensities. Finally, we also propose additional phase measurements for estimating the statistical moments of more complex source distributions. Our results are promising for implementing phase measurements in sub-Rayleigh imaging tasks such as exoplanet detection.
Research-Based Proposals on Optical Spectroscopy and Secondary Students’ Learning Outcomes
Authors: Buongiorno Daniele , Michelini Marisa
Published: August 2019

Optical spectroscopy is a conceptual referent linking classical and modern physics which provides experiments on the atomic structure and light-matter interaction. Its disciplinary relevance, as well as its importance on the cultural and social levels is widely recognized but few efforts have been made to integrate those aspects in education. Our Physics Education Research Unit from Udine University (Italy) designed an educational method on optical spectroscopy for secondary school students to directly involve them in experimental and interpretative tasks which allow them to highlight the link between energy level in atoms and luminous emission. In the theoretical framework of the Model of Educational Reconstruction, the educational approach involves an analysis of the main conceptual knots on the basis of a significant - if not vast - literature concerning the interpretation of optical spectra. By means of design-based research methods, we designed several intervention modules in which interpretative issues related to the analysis of simple optical spectra from different sources are highlighted using inquiry-based learning strategies. Learning outcomes were monitored by means of empirical research using pre/post-tests and tutorials.
A case study about the comprehension of electromagnetic induction in Northern Italy
Authors: Giliberti M , Giliberti E , Cavinato M
Published: August 2019

We discuss a study about Italian upper secondary school, undergraduate and graduate students’ and teacher’s misunderstanding in dealing with electromagnetic induction. We suspect that most difficulties, that we found substantially common at all levels of education, come from the very poor link, generally presented in teaching, between the Faraday’s law and the Lorentz force. We also suggest that the understanding of inductive phenomena/problems/exercises could benefit from taking into account also the magnetic vector potential “point of view”.
Teaching middle school physics in Observer-dependence approach: pedagogical and curricular aspects
Authors: Stein Ben , Stein Hana , Galili Igal
Published: August 2019

Physics curriculum of middle school and high school is based on the classic perspective of the 19th century and avoids dealing with the concept of observer (frame of reference). This by far holds regarding the curriculum of middle school, as even though it includes numerous observer-dependent concepts (location, trajectory, displacement, velocity, force, energy, work), it entirely excludes observer and observer dependent description of reality, and they are not taught as such.

This tradition apparently draws on the assumption that students are incapable of learning observer dependent concepts because that requires an account with multiple answers valid for different observers. For that reason it is considered to be as a sort of advanced subject matter that should be treated at higher education level.

We empirically checked this convention and discovered that 9th grade students succeeded in applying frame of reference dependence to their accounts of daily experiences. For example, they were able to construct graphs expressing dependence of displacement, distance, and velocity on time in the perspective of different inertial frames of references. The results clearly indicate that integrated observer-dependent concepts in middle school promises substantial educational and pedagogical benefits (e.g. wider space of learning, intuitively and meaningful learning, students’ engagement and adequate image of science).