bluuebunny/crossref_metadata_2025 huggingface dataset:
Sustainable development: Using stone dust to replace a part of sand in concrete mixture
Authors: Turuallo Gidion , Mallisa Harun , Rupang Nicodemus
Published: December 2020

Stone dust is a waste material produced in stone crusher industry. Stone dust produced from the crushed stone industry is quite numerous. PT Mega Beton Jaya is a stone crushed industry, which is located in Buluri, Palu, has difficulty in providing a location to accommodate the waste of stone dust. In addition, the community around this industry is quite worried with the waste ash as the air around the industry contaminated with the stone ash. This study aims to find out the maximum percentage of stone dust to substitute sand in a concrete mix to obtain the maximum strength and good workability. The cement used throughout this work was Portland cement composite (PCC) produced by PT Semen Tonasa, the sand was taken from Palu river, while the stone dust and coarse aggregate were taken from PT Mega Beton Jaya stone crushed industry. The percentages of stone dust replacing sand were varied from 0, 20, 30, 40, 60, 80 and 100% to find out the maximum percentage of stone dust to replace sand from river to produce the maximum compressive strength of concrete. The results of this research showed that the maximum percentage of stone dust, which could replace river sand in concrete mixture was 40% with the strength 15% higher than that of concrete with natural sand only. The higher the percentages of stone dust, which were used to replace a part of sand in concrete mixtures resulted the lower slump of concrete. In addition, the replacing natural sand with stone dust higher than 20% produced the value of slump for both normal and high strength concretes lower than those concretes with natural sand only.
Miniature Automatic Watering System of Ornamental Plant at Permanent Seedbed of Central Management of Regional River Flow (BPDAS) Palu–Poso Using Microcontroller Arduino-Uno
Authors: Subito Merry , Nurrahmi Sitti , Mustari Aidynal
Published: December 2020

The results of the research carried out were successful in making the Miniature automatic watering system designed using Arduino UNO as a brain control system, DHT22 sensors to measure temperature and humidity environment, RTC module as a time saver, water pump and DC motor used for the watering mecanism. After testing all the tools and sensors, the instrument can be run well and normally. Watering done on the morning (08:00 wita) using the RTC as the reservoir time, the RTC will inform the arduino so arduino will command to a motorcycle do a watering. When air temperature around detected more than 18oC and soil humidity less than 60% then the system will automatically did watering over past 3 minutes. So that automatic watering system can be used to help out watering an ornamental plant based on sensors detected related to temperature and soil humidity at the green house.
Comparison of load resistor and battery on controlling buck boost converter using fuzzy-pi method
Authors: Massarang Maryanto , Jumiyatun Jumiyatun , Salu Pirade Yulius , Mahwada Mahwada , Fatmwati Andi
Published: December 2020

This paper discusses about controlling the buck boost converter output voltage remains constant by comparing of loads resistor and battery. Buck boost converter output voltage tends to be unstable when given a disturbance with a variety of loads, for that it needs proper control to adjust the duty cycle. The controls that will be used are a combination of conventional control methods, i. e. Proportional Integral (PI) and intelligent control, i. e. Fuzzy logic. The results show that the combination of PI control and Fuzzy Logic can improve performance, i. e. small errors close to zero and the buck boost converter output voltage remains constant even though the load is varied, i. e. resistors and battery.
Control of light Intensity via Microcontroller for the Efficiency of Electrical Energy
Authors: Sriwati  , Aedi Al Abshari Tzal , Suyuti Ansar , Ahmad Andani , Umraeni Salam A. Ejah
Published: December 2020

Lighting is a factor to get a safe and comfortable environment. Good lighting allows one to see objects that are done clearly, and can give a refreshing view. Conversely, if the room has poor lighting can cause eye fatigue, therefore it is necessary to control the intensity of light-based microcontroller to regulate the lighting of a room automatically. his research was made by designing a lighting model using a dimmer circuit based on ATMega328 microcontroller, LDR sensor (Light Dependent Resistor) and Bluetooth HC-06. The working principle of the LDR sensor is receiving light from the outside which causes changes in the input voltage level to the microcontroller while the Bluetooth HC-06 works by connecting a Bluetooth device with a smartphone that has installed the PWM Light Control application. which is then processed by microcontroller output in the form of pulse voltage (PWM) in the dimmer circuit to adjust the dim and bright lights. Results for electricity voltage (Volt), Electricity (Ampere), Light level (Lux) and electrical power used. At each increase from 0-255 PWM which is channeled to the dimmer circuit, the power is 0-13,0357 watts, comparable to before using a circuit of around 13,5036 watts with a percentage of 1. 7% with a 15-Watt lamp, the light conditions are stable in brightness. The distance of control of this tool reaches 26. 15 m with 1 barrier wall and still works with 3 barrier walls with a distance of 21. 45 m. So that the use of electric power and light can be adjusted to the needs.
A Reliable Offline Web System for Small and Medium Industries
Authors: Tahir Zulkifli , Dasmito Al-Riefqy , Adnan  , Niswar Muhammad , Wardi
Published: December 2020

The information technology such as web-based systems has been widely implemented in Small and Medium Industries (SMIs) to improve the management and effectiveness. However, the web-based systems still discover the problem when those are applied to the SMIs that located in the rural areas which generally have low network quality. The problem can also occur due to various conditions such as unstable electricity or during a disaster. Based on the problem, the web-based systems should meet the reliability standards so it can continue to be work in every condition. This study proposes a reliable offline web system of React JavaScript with the service worker concept as an effort to overcome the problem. The results not only can improve the performance of web-based systems in various conditions but also encourage other SMIs to use the web-based system for their industrial process.
Ring Road Development Problems in Metropolitan Cities of Indonesia
Authors: Tohjiwa Agus Dharma
Published: December 2020

The development of ring roads in Indonesia are not only as a means of transportation needs but also as a means for the urban regional development. Although it produces many economic benefits, this development produces many new problems, especially in metropolitan cities. The aim of this research is to formulate and describe the problems of ring road development in the metropolitan cities of Indonesia. The data collection was carried out through a survey and interview with related institutions in 7 cities, they are Medan, Palembang, Bandar Lampung, Surabaya, Makassar, Manado, and Jakarta. The result of this research shows that there are 23 problems found there. The most common problem found are the uncontrolled housing development (urban sprawl) and public transportation (occurs in 6 cities). The second most problems found are regional connectivity, ring road intersection, housing access, settlement facilities, and social problems (occurs in 5 cities). All the existing problems can be classified into 6 problem types, they are (1) problem of ring road preparation and construction, (2) problem of disobedience and inconsistency of regulation, (3) problem of spatial planning and urban development, (4) problem of housing growth and facilities provision, (5) problem of coordination among institution and regulatory synchronization, and (6) problem of environmental management related to the integration of ring road and settlement development.
Conséquences éthiques et sociales de biomarqueurs prédictifs de la mort chez l’homme
Authors: Gaille Marie , Araneda Marco , Dubost Clément , Guillermain Clémence , Kaakai Sarah , Ricadat Élise , Todd Nicolas , Rera Michael
Published: December 2020

La recherche fondamentale sur le vieillissement a pris un tour intéressant ces dernières années avec un développement rapide des biomarqueurs prédictifs de mortalité chez les organismes modèles, notamment la drosophile, ainsi que chez l’être humain à travers les améliorations des approches d’identification en masse de molécules circulantes. Ces développements conduisent à un déplacement de notre capacité de prédiction de survenue de la mort, du niveau historiquement populationnel au niveau individuel. Nous interrogeons ici les implications éthiques, médicales et sociales de ce changement d’échelle.
Le vieillissement
Authors: Fontanilla Paula , Willaume Simon , Thézé Benoit , Moussa Angela , Pennarun Gaëlle , Bertrand Pascale
Published: December 2020

Le vieillissement est associé à une accumulation de cellules sénescentes produisant un environnement cellulaire inflammatoire qui pourrait expliquer différentes maladies liées à l’âge. Diverses situations menant à la sénescence sont liées à la présence de dommages de l’ADN. De plus, de nombreux syndromes progéroïdes sont associés à une instabilité du génome ou de la structure nucléaire. Nous discuterons du lien étroit existant entre l’altération des lamines, composants de l’enveloppe nucléaire, et le vieillissement cellulaire. Nous verrons que l’altération de l’enveloppe nucléaire, comme celle observée dans la Progéria, est aussi associée à des défauts de réparation de l’ADN, à une persistance de dommages de l’ADN et à un phénotype inflammatoire.
Anatomie der Arterien: Untere Extremität
Authors: Kalka Christoph
Published: December 2020

Anatomie, Morphologie und Hämodynamik sind elementare Bausteine der Gefäßmedizin. Insbesondere die Kenntnis der Anatomie der Arterien der unteren Extremität ist für weiterführende diagnostische Maßnahmen wie die farbkodierte Duplexsonografie von großer Bedeutung. Der vorliegende Artikel zeigt pragmatisch in parallelen Bildern den anatomischen Verlauf der Beinarterie zum Skelett, die Projektion der Anatomie auf die Haut mit der erforderlichen Schallkopfführung und den sonografischen Normalbefund.
Eine aktuelle Übersicht über die Einflussfaktoren der Stammzellspender auf das regenerative Potential von Fettgewebsstammzellen
Authors: Kuhlmann Constanze , Schenck Thilo Ludwig , Haas Elisabeth Maria , Giunta Riccardo , Wiggenhauser Paul Severin
Published: December 2020

Hintergrund Nicht nur regenerative Therapie wie zellassistierter Lipotransfer (cell assisted lipotransfer) sondern auch präklinische experimentelle Studien verwenden in der Plastischen Chirurgie Stammzellen aus Fettgewebe, sogenannte Adipose tissue-derived Stem Cells (ASCs). Hierbei haben allerdings vom jeweiligen Stammzellspender abhängige Faktoren einen entscheidenden Einfluss auf die Zellausbeute und das regenerative Potential von ASCs und der Stromal vascular Fraction (SVF). Ziel dieser Übersichtsarbeit war es daher, diese Einflussfaktoren des Stammzellspenders darzustellen und anhand des aktuellen Wissenstands zu beurteilen.

Methoden Es erfolgte eine intensive Literaturrecherche in der der National Library of Medicine, mit Fokus auf Einflussfaktoren der Stammzellspender, die eine Beeinflussung der Zellausbeute und des regenerativen Potentials von humanen ASCs und SVF in vorherigen Studien gezeigt haben.

Ergebnisse Aktuell gibt es eine Vielzahl von Studien, welche sich mit den Einflussfaktoren des Stammzellspenders auseinandersetzen. Allerdings sind diese Faktoren sehr inhomogen und teilweise sogar widersprüchlich, so dass hier noch weiterer Forschungsbedarf besteht. Dennoch gibt es einige Faktoren, die gemäß der aktuellen Literatur gehäuft untersucht wurden: Alter, Geschlecht, Gewicht, Nebenerkrankungen (z. B. Diabetes, Lipödem) sowie spezielle Medikamente (Antidepressiva, Antihormontherapie) und Chemotherapie.

Schlussfolgerung Wir empfehlen, bei experimentellen und klinischen Arbeiten mit ASCs/SVF eine Charakterisierung des Patientenkollektivs zu veröffentlichen, so dass mögliche Beeinflussungen durch oben genannte Faktoren kommuniziert werden und eine bessere Vergleichbarkeit von Studien ermöglicht wird. Darüber hinaus kann aber auch mit einer präzisen Anamnese und körperlichen Untersuchung vorab ein möglichst homogenes Patientenkollektiv für die Sammlung von Proben für wissenschaftliche Arbeiten konstruiert werden. Auch könnten die Ergebnisse dazu beitragen, den Erfolg zukünftiger ASC-basierter Therapien einzuschätzen.
Anatomie der tiefen Beinvenen
Authors: Murena-Schmidt Renate
Published: December 2020

Die Kenntnis der Anatomie des venösen Systems ist die Basis für unser klinisches Tun in der Phlebologie, gerade im Hinblick auf eine gute Diagnostik und Therapie bei tiefer Beinvenenthrombose und auch für die Wahl der adäquaten Therapie bei Krankheiten des oberflächlichen Venensystems.

Die Nomenklatur der tiefen Beinvenen hat sich über die Jahre geändert. Damit wir in der phlebologischen Welt international „eine Sprache sprechen“, folgt hier eine Zusammenstellung und Darstellung der Anatomie der tiefen Beinvenen und deren Bezeichnung aus der Literatur (im Wesentlichen aus dem UIP-Konsensus-Dokument zur venösen anatomischen Terminologie).
Sexuelle Arbeit von Männern*: Erscheinungsformen und Unterstützungsbedarfe
Authors: Fixemer Tom
Published: December 2020

Sexarbeit wird überwiegend von Frauen* geleistet. Dennoch darf sexuelle Arbeit von männlichen* Sexarbeitenden nicht ignoriert werden. Der vorliegende Praxisbeitrag beschreibt verschiedene Formen und Orte der Sexarbeit, die von Cis-Männern und Queers überwiegend für Cis-Männer erbracht wird. Diverse Fallbeispiele illustrieren die Lebenswelten männlicher* Sexarbeit. Zudem werden die Anliegen und Unterstützungsbedarfe von Männern* in Sexarbeitskontexten herausgearbeitet und vor dem Hintergrund des neuen Prostituiertenschutzgesetzes (ProstSchG) reflektiert. Der Autor hat sozialpädagogische Erfahrung in der Streetwork- und sozialen Szenearbeit und ist mit dem Arbeitskreis deutschsprachiger Strichereinrichtungen (AKSD) und dem Bündnis der Fachberatungsstellen für Sexarbeiterinnen und Sexarbeiter (bufas) vernetzt.
Sexarbeitsaktivismus aus der Perspektive der Verbandsarbeit: Die Aktivitäten des Berufsverbands für erotische und sexuelle Dienstleistungen e. V.
Authors: Gloss Nadine
Published: December 2020

In diesem Beitrag wird die Arbeit des Berufsverbands für erotische und sexuelle Dienstleistungen e. V. (BesD) vorgestellt, insbesondere wie sich der BesD in Deutschland als Akteur in der Sexarbeitsbewegung positioniert und mit welchen Strategien er den Kampf für Sexarbeitsrechte voranbringt. Über die letzten sieben Jahre seit seiner Gründung im Jahr 2013 wurde der Verband von Medien und Politik zunehmend als Ansprechpartner für Sexarbeit wahrgenommen. Aus einer Gruppe von fünfzig engagierten Frauen, die sich für die weitere Entkriminalisierung der Sexarbeit und eine vernünftigere Rechtslage einsetzten, wuchs ein vielfältiges Netzwerk an Menschen aus unterschiedlichen Bereichen der Sexarbeit, die sich aktiv für ihre Arbeitsrechte einsetzen und im Rahmen des BesD zunehmend professionalisieren.
Sexuelle Gesundheit in der Sexarbeit vor dem Hintergrund des Prostituiertenschutzgesetzes (ProstSchG): Einschätzungen von Berater*innen und Sexarbeiter*innen
Authors: Körner Christine , Netzelmann Tzvetina Arsova , Ceres Maia , Hacke Deborah , Steffan Elfriede
Published: December 2020

Einleitung Das 2017 in Deutschland in Kraft getretene Prostituiertenschutzgesetz (ProstSchG) verlangt eine Pflichtberatung für Sexarbeitende, die nun zusätzlich zu den bereits bestehenden freiwillig wahrnehmbaren Angeboten auf Grundlage des Infektionsschutzgesetzes (IfSG) von den Gesundheitsämtern vorgehalten werden muss. Beide Angebotsformate überschneiden sich darin, dass sie dem Erhalt der sexuellen Gesundheit dienen sollen, unterscheiden sich aber in anderen Aspekten grundlegend (u. a. thematisch, Freiwilligkeit).

Forschungsziele Ziel der vorliegenden Pilotstudie war es zu erkunden, wie der Öffentliche Gesundheitsdienst (ÖGD) die bestehenden gesundheitlichen Angebote und die neue ProstSchG-Pflichtberatung für Sexarbeitende organisiert, wie diese neue Angebotsstruktur von den Sexarbeitenden angenommen wird und wie sie insgesamt aus fachlicher Sicht zu bewerten ist.

Methoden Im Herbst 2019 wurden Interviews mit N = 11 Mitarbeitenden von Gesundheitsämtern, Fachberatungsstellen und Fachverbänden durchgeführt und zudem die Sichtweisen von N = 185 Sexarbeitenden mittels Online-Befragung eingeholt.

Ergebnisse Es zeigte sich, dass die noch im Prozess befindliche Umsetzung regional sehr unterschiedlich erfolgt und diverse Probleme aufwirft (z. B. durch fehlende Freiwilligkeit und fehlende Vertraulichkeit). Durch die neue Angebotsstruktur werden zahlreiche Sexarbeiter*innen nicht (mehr) erreicht. Diejenigen Sexarbeiter*innen, die die ProstSchG-Pflichtberatung absolviert haben, äußern teilweise deutliche Kritik (z. B. abschätzige Behandlung, fehlende Fachkompetenz für bestimmte Bereiche der Sexarbeit wie BDSM).

Schlussfolgerung Hilfebedürftige Sexarbeitende sind auf die Angebote des ÖGD angewiesen. Der ÖGD sollte nach außen viel deutlicher machen, dass es für Sexarbeitende neben der ProstSchG-Pflichtberatung auch eine freiwillige und anonym wahrnehmbare Beratung mit medizinischer STI-/HIV-Diagnostik sowie teilweise zusätzliche psychosoziale Beratungsangebote gibt. Diese freiwillig und anonym wahrnehmbaren Angebote einschließlich der Beratung und der aufsuchenden Arbeit an Orten der Sexarbeit sind essenziell, um gerade vulnerable Sexarbeitende zu erreichen, ihre sexuelle Gesundheit zu fördern und sie in Not- und Krisenfällen zu unterstützen.
Initial experience with per-rectal endoscopic myotomy for Hirschsprung’s disease: medium and long term outcomes of the first case series of a novel third-space endoscopy procedure
Authors: Bapaye Amol , Dashatwar Parag , Biradar Vishnu , Biradar Shital , Pujari Rajendra
Published: December 2020

Introduction Hirschsprung’s disease (HSCR) is congenital aganglionosis affecting the hindgut and presents with constipation. Surgical pull-through is the current standard treatment but causes morbidity. Per-rectal endoscopic myotomy is a novel third-space endoscopy technique for treating short-segment (SS)-HSCR.

Methods Retrospective study of SS-HSCR patients diagnosed on history, contrast enema, rectal biopsies, and anorectal manometry, and treated by PREM. The aganglionic segment was mapped before PREM was performed using third-space endoscopy principles. Stool frequency and laxative usage before and after PREM were compared.

Results Nine patients (age 7.5 [± 5.2] years; 7 male) underwent PREM during a 4-year period. Mean aganglionic segment length was 6.3 cm, mean procedure time 96.1 minutes, and mean length of hospital stay 2.5 days. Median follow-up was 17 months (range 9–58 months). Stool frequency was 1/4.4 days before vs. 1/1.2 days after PREM (P = 0.0004). Mean laxative usage was 5.4 units of laxative (UL) before vs. 0.4 UL after PREM (P = 0.0002). No laxatives were used by 6/9 patients after PREM. The single adverse effect seen (anal stenosis) was treated with dilatation.

Conclusions PREM is a safe and effective minimally invasive procedure to treat SS-HSCR and results in long-term response.
Nachhaltigkeit: Spenden von ausgemustertem Krankenhaus-Equipment
Authors: Rau Klaus
Published: December 2020

Der Bedarf an Krankenhausbetten und medizinischen Hilfsmitteln in Südungarn ist groß, da eine Neubeschaffung aufgrund sehr knapper Investitionsmittel nur beschränkt bis gar nicht möglich ist. Der DRK-Kreisverband Nürtingen-Kirchheim kümmert sich seit Jahren darum, dass in Deutschland aussortierte Betten und Hilfsmittel, die aber noch gut in Schuss sind, ihren Weg nach Ungarn finden und nicht auf dem Müll landen.
Evaluating trust and shared group identities in emergent social learning processes in the Zambezi river basin
Authors: Lumosi Caroline K. , Pahl-Wostl Claudia , Scholz Geeske
Published: December 2020

Social learning in natural resource management is considered important for addressing complex problems by supporting multi-stakeholder interactions in problem framing and co-construction of solutions. Despite the considerable progress in the social learning discourse, few scholars have empirically examined relational features in social learning interactions. Relational features such as trust and shared group identities are important for supporting engagement and interaction among actors. This study analyzed emergent social learning processes in transboundary river basin cooperation processes in the Zambezi basin. To do this, data was conducted through in-depth interviews with diverse actors, observations of participatory workshops, and review of documents on transboundary cooperation processes in the Zambezi basin. The study evaluated how trust and shared group identities shaped learning spaces (opportunities for interaction, deliberation and reframing) and in turn impacted transboundary river basin cooperation. The study found that trust and shared group identities had a crucial impact on learning spaces and in turn impacted transboundary river basin cooperation in the Zambezi basin. The results suggest that leveraging on trust and shared group identities can play a critical role in stimulating cooperation processes. However, it is not a guarantee for cooperation. This study highlights that structural-learning spaces such as institutions support the development of binding commitments and enduring shared practices. However, success of such institutionalization is strongly influenced by the prior development of trust and a shared social identity.
Structured ion layers explain decay length increase in highly concentrated electrolyte solutions
Authors: Ishimaru Matthew
Published: December 2020

Researchers propose a simple physical mechanism that suggests strongly correlated structures lead to shifts in screening length.
Benchmarking metrics for inferring functional connectivity from multi-channel EEG and MEG: A simulation study
Authors: Yu Meichen
Published: December 2020

I present a systematic evaluation of different types of metrics, for inferring magnitude, amplitude, or phase synchronization from the electroencephalogram (EEG) and the magnetoencephalogram (MEG). I used a biophysical model, generating EEG/MEG-like signals, together with a system of two coupled self-sustained chaotic oscillators, containing clear transitions from phase to amplitude synchronization solely modulated by coupling strength. Specifically, I compared metrics according to five benchmarks for assessing different types of reliability factors, including immunity to spatial leakage, test–retest reliability, and sensitivity to noise, coupling strength, and synchronization transition. My results delineate the heterogeneous reliability of widely used connectivity metrics, including two magnitude synchronization metrics [coherence (Coh) and imaginary part of coherence (ImCoh)], two amplitude synchronization metrics [amplitude envelope correlation (AEC) and corrected amplitude envelope correlation (AECc)], and three phase synchronization metrics [phase coherence (PCoh), phase lag index (PLI), and weighted PLI (wPLI)]. First, the Coh, AEC, and PCoh were prone to create spurious connections caused by spatial leakage. Therefore, they are not recommended to be applied to real EEG/MEG data. The ImCoh, AECc, PLI, and wPLI were less affected by spatial leakage. The PLI and wPLI showed the highest immunity to spatial leakage. Second, the PLI and wPLI showed higher test–retest reliability and higher sensitivity to coupling strength and synchronization transition than the ImCoh and AECc. Third, the AECc was less noisy than the ImCoh, PLI, and wPLI. In sum, my work shows that the choice of connectivity metric should be determined after a comprehensive consideration of the aforementioned five reliability factors.
Site percolation thresholds on triangular lattice with complex neighborhoods
Authors: Malarz Krzysztof
Published: December 2020

We determine thresholds pc for random site percolation on a triangular lattice for neighborhoods containing nearest (NN), next-nearest (2NN), next-next-nearest (3NN), next-next-next-nearest (4NN), and next-next-next-next-nearest (5NN) neighbors, and their combinations forming regular hexagons (3NN+2NN+NN, 5NN+4NN+NN, 5NN+4NN+3NN+2NN, and 5NN+4NN+3NN+2NN+NN). We use a fast Monte Carlo algorithm, by Newman and Ziff [Phys. Rev. E 64, 016706 (2001)], for obtaining the dependence of the largest cluster size on occupation probability. The method is combined with a method, by Bastas et al. [Phys. Rev. E 90, 062101 (2014)], for estimating thresholds from low statistics data. The estimated values of percolation thresholds are pc(4NN)=0.192410(43), pc(3NN+2NN)=0.232008(38), pc(5NN+4NN)=0.140286(5), pc(3NN+2NN+NN)=0.215484(19), pc(5NN+4NN+NN)=0.131792(58), pc(5NN+4NN+3NN+2NN)=0.117579(41), and pc(5NN+4NN+3NN+2NN+NN)=0.115847(21). The method is tested on the standard case of site percolation on the triangular lattice, where pc(NN)=pc(2NN)=pc(3NN)=pc(5NN)=12 is recovered with five digits accuracy pc(NN)=0.500029(46) by averaging over one thousand lattice realizations only.
Collective escape and supratransmission phenomena in a nonlinear oscillators chain
Authors: Mekontchou Foudjio Michael , Thomas Ndjomatchoua Frank , Lawrence Gninzanlong Carlos , Tchawoua Clément
Published: December 2020

In this study, the collective escape and supratransmission phenomena along a nonlinear chain of coupled particles subjected to a cubic on-site potential are considered. It is shown that the minimum initial on-site amplitude for which there is a collective escape increases with the nonlinear coupling. When the chain is forced at one end by a periodical excitation, the system exhibits supratransmission phenomenon in both lower and upper forbidden bandgaps, and, subsequently, it appears that the driving amplitude threshold for supratransmission in the upper forbidden bandgap frequency decreases with the nonlinear coupling. Depending on the frequency range of the gap frequency, the collective escape and supratransmission can occur simultaneously; otherwise, the supratransmission prevails.
Ion microfield in ultracold strongly coupled plasma
Authors: Bobrov A. A. , Bronin S. Ya. , Klyarfeld A. B. , Korchagin D. S. , Zelener B. B. , Zelener B. V.
Published: December 2020

The ion microfield distribution in neutral and positively charged points is studied for two-component ultracold plasma using molecular dynamics simulation. The calculations are made in a wide range of the strongly coupled parameter. The particles are treated within classical statistical mechanics using an electron–ion Coulomb potential in the entire range of distances between the particles, without any restrictions. The results can be used for any plasma in which quantum effects are not significant. Comparison with results of other authors is made.
Nonlinear optical properties of halide perovskites and their applications
Authors: Zhou Yixuan , Huang Yuanyuan , Xu Xinlong , Fan Zeyu , Khurgin Jacob B. , Xiong Qihua
Published: December 2020

Nonlinear optics has undergone dramatic developments in the past 60 years, which has revolutionized the photonic and optoelectronic fields with many essential applications such as electro-optic switching, frequency mixing, optical parametric oscillation, optical phase conjugation, and so forth. As one of the new and promising candidates for both next-generation photovoltaic and optoelectronic devices, halide perovskite semiconductors have attracted extensive research attention because of their excellent electrical and optical properties demonstrated in the linear optical regime. In the past five years, halide perovskites have become a new research frontier of nonlinear optical materials because their highly tunable chemical components and multiple structures provide a variety of outstanding nonlinear optical properties, which support a broad scope of nonlinear optical applications. In this review, we have summarized the nonlinear optical properties of halide perovskites categorized according to the second-, third-, and high-order processes. Aside from the more conventional nonlinear effects, such as sum and difference frequency generation, this review also pays attention to the lesser known but important nonlinear phenomena, such as linear and circular photogalvanic effects, the high-order shift current effect, and the multi-photon pumped photoluminescence. We have also reviewed and summarized the nonlinear applications of halide perovskites, including multi-photon pumped photoluminescence imaging, multi-photon pumped amplified spontaneous emission and lasing, sub-bandgap and self-powered photodetection, all-optical and electro-optic modulation, saturable absorption, optical limiting, and so on. It is our belief that halide perovskites have proven to be excellent candidates for promoting the upgrading and updating of nonlinear optical devices with greatly improved performance and novel functionalities.
Annealing effect on photoluminescence of two dimensional WSe2/BN heterostructure
Authors: Liu Yonglai , Liu Caixing , Ma Zongwei , Zheng Ganhong , Ma Yongqing , Sheng Zhigao
Published: December 2020

Controlling or eliminating the extrinsic interfacial effects is an important concern in the studies of two-dimensional van der Waals (2D vdW) heterostructures. In this Letter, by using WSe2/BN as a model, the annealing effect on the elimination of extrinsic interfacial effects in 2D vdW heterostructures was studied. The formation of the WSe2/BN interface can generate interfacial defects and significantly regulate the type and peak intensity percentage of WSe2 photoluminescence (PL) peak. It is intriguing to find that the thermal annealing effect on the optical property is opposite to that from extrinsic defects. By optimizing the annealing temperature, the PL of the functional-layer WSe2 in the heterostructure is gradually restored. This finding demonstrates that the thermal annealing can efficiently minimize the extrinsic interfacial effects, which may provide a simple and low-cost route to fabricate high-quality 2D vdW devices.
Spin-gapless semiconductors: Fundamental and applied aspects
Authors: Rani Deepika , Bainsla Lakhan , Alam Aftab , Suresh K. G.
Published: December 2020

Spin-gapless semiconductors (SGSs) are new states of quantum matter, which are characterized by a unique spin-polarized band structure. Unlike conventional semiconductors or half-metallic ferromagnets, they carry a finite bandgap for one spin channel and a close (zero) gap for the other and thus are useful for tunable spin transport applications. It is one of the latest classes of materials considered for spintronic devices. A few of the several advantages of SGS include (i) a high Curie temperature, (ii) a minimal amount of energy required to excite electrons from the valence to conduction band due to zero gap, and (iii) the availability of both charge carriers, i.e., electrons as well as holes, which can be 100% spin-polarized simultaneously. In this perspective article, the theoretical foundation of SGS is first reviewed followed by experimental advancements on various realistic materials. The first band structure of SGS was reported in bulk Co-doped PbPdO2, using first-principles calculations. This was followed by a large number of ab initio simulation reports predicting SGS nature in different Heusler alloy systems. The first experimental realization of SGS was made in 2013 in a bulk inverse Heusler alloy, Mn2CoAl. In terms of material properties, SGS shows a few unique features such as nearly temperature-independent conductivity (σ) and carrier concentration, a very low temperature coefficient of resistivity, a vanishingly small Seebeck coefficient, quantum linear magnetoresistance in a low temperature range, etc. Later, several other systems, including 2-dimensional materials, were reported to show the signature of SGS. There are some variants of SGSs that can show a quantum anomalous Hall effect. These SGSs are classic examples of topological (Chern) insulators. In the later part of this article, we have touched upon some of these aspects of SGS or the so-called Dirac SGS systems as well. In general, SGSs can be categorized into four different types depending on how various bands corresponding to two different spin channels touch the Fermi level. The hunt for these different types of SGS materials is growing very fast. Some of the recent progress along this direction is also discussed.
A cryogenic continuously rotating half-wave plate mechanism for the POLARBEAR-2b cosmic microwave background receiver
Authors: Hill C. A. , Kusaka A. , Ashton P. , Barton P. , Adkins T. , Arnold K. , Bixler B. , Ganjam S. , Lee A. T. , Matsuda F. , Matsumura T. , Sakurai Y. , Tat R. , Zhou Y.
Published: December 2020

We present the design and laboratory evaluation of a cryogenic continuously rotating half-wave plate (CHWP) for the POLARBEAR-2b (PB-2b) cosmic microwave background receiver, the second installment of the Simons Array. PB-2b will observe at 5200 m elevation in the Atacama Desert of Chile in two frequency bands centered at 90 GHz and 150 GHz. In order to suppress atmospheric 1/f noise and mitigate systematic effects that arise when differencing orthogonal detectors, PB-2b modulates linear sky polarization using a CHWP rotating at 2 Hz. The CHWP has a 440 mm clear aperture diameter and is cooled to ≈50 K in the PB-2b receiver cryostat. It consists of a low-friction superconducting magnetic bearing and a low-torque synchronous electromagnetic motor, which together dissipate <2 W. During cooldown, a grip-and-release mechanism centers the rotor to <0.5 mm, and during continuous rotation, an incremental optical encoder measures the rotor angle with a noise level of 0.1 μrad/Hz. We discuss the experimental requirements for the PB-2b CHWP, the designs of its various subsystems, and the results of its evaluation in the laboratory. The presented CHWP has been deployed to Chile and is expected to see first light on PB-2b in 2020 or 2021.
A tunable stress dilatometer and measurement of the thermal expansion under uniaxial stress of Mn3Sn
Authors: Ikhlas Muhammad , Shirer Kent R. , Yang Po-Ya , Mackenzie Andrew P. , Nakatsuji Satoru , Hicks Clifford W.
Published: December 2020

We present a method for measuring thermal expansion under tunable uniaxial stresses and show measurements of the thermal expansion of Mn3Sn, a room temperature antiferromagnet that exhibits a spontaneous Hall effect, under uniaxial stresses of up to 1.51 GPa compression. The measurement of thermal expansion provides thermodynamic data about the nature of phase transitions, and uniaxial stress provides a powerful tuning method that does not introduce disorder. Mn3Sn exhibits an anomaly in its thermal expansion near ∼270 K, associated with a first-order change in its magnetic structure. We show that this transition temperature is suppressed by 54.6 K by 1.51 GPa compression along [0001]. We find the associated entropy change at the transition to be ∼ 0.1 J mol−1 K−1 and to vary only weakly with applied stress.
Band alignment of ScAlN/GaN heterojunction
Authors: Fu Hanlin , Goodrich Justin C. , Tansu Nelson
Published: December 2020

The natural band alignments of ScxAl1−xN/GaN heterojunctions, with Sc-contents ranging from 0% to 25%, are investigated by first-principles density functional theory with the local density approximation. Type-I ScxAl1−xN/GaN heterojunctions with large conduction band offsets (CBOs) and valence band offsets (VBOs) are found. The band alignment of nearly lattice-matched ScAlN (x = ∼18.75%) with respect to GaN (CBO = 1.74 eV, VBO = 0.34 eV) is also calculated for future implementation in GaN-based quantum wells and power devices. Our findings provide useful band parameters necessary for enabling the implementation of ScAlN alloys in GaN-based power and optoelectronic devices.
Improvement in ferroelectricity and breakdown voltage of over 20-nm-thick HfxZr1−xO2/ZrO2 bilayer by atomic layer deposition
Authors: Onaya Takashi , Nabatame Toshihide , Inoue Mari , Jung Yong Chan , Hernandez-Arriaga Heber , Mohan Jaidah , Kim Harrison Sejoon , Sawamoto Naomi , Nagata Takahiro , Kim Jiyoung , Ogura Atsushi
Published: December 2020

The ferroelectricity of metal–ferroelectric–metal capacitors with a ferroelectric HfxZr1−xO2/ZrO2 (HZO/ZO) bilayer thicker than 20 nm formed by atomic layer deposition and postdeposition annealing at 600 °C was investigated. The HZO/ZO capacitors exhibited a higher remanent polarization (2Pr = Pr+ − Pr−) and breakdown voltage (Vbd) than capacitors with a HfxZr1−xO2 (HZO) single layer. In particular, a HZO (15 nm)/ZO(10 nm) (HZ15Z10) capacitor exhibited excellent Vbd and 2Pr values of 6.7 V and 14 μC/cm2, respectively, which are much higher than those (4.3 V and 10 μC/cm2, respectively) for a HZO (15 nm) (HZ15) capacitor. The HZ15Z10 capacitor also exhibited higher endurance, a smaller wake-up effect (∼5%), and superior fatigue properties up to 108 switching cycles, compared to a HZ15 capacitor, which exhibited a large wake-up effect (∼15%) and large 2Pr degradation at 108 cycles. The wake-up behavior is attributed to domain depinning mainly related to the redistribution of oxygen vacancies and transformation from the nonferroelectric phase to the ferroelectric orthorhombic (O) phase during field cycling. The HZO/ZO bilayer grew a larger grain size with the ZO nucleation layer, which is twice as large as that of the HZO single layer, and the former structure exhibited more stable bulk-like ferroelectricity. Although the ferroelectric O phase in HZO decreased with increasing HZO thickness, the HZO/ZO structure had a larger fraction of the O phase than the HZO structure. Considering the manufacturing process of ferroelectric devices, these thick HZO/ZO bilayers are promising ferroelectric materials.
On the instability of the melting film over a moving hot plate
Authors: Sisoev G. M. , Çekiç G.
Published: December 2020

The flow of a viscous film emerging over a plate moving through a linear elastic solid in the case when the plate temperature exceeds the melting temperature of the solid is studied. An approximate model for the melting film flow and the solid temperature is stated in the case of known dependencies of the kinematic viscosity and thermal conductivity of the melt on temperature. In the case of constant kinematic viscosity and thermal conductivity, the model describing steady flows was formulated in the work of G. G. Chernyi, “The motion of a plate in a melting solid medium,” J. Appl. Math. Mech. 55, 287 (1991), where a self-similar solution was analytically found for relatively thin films. In this paper, the self-similar solution is numerically calculated in a general case, and it is demonstrated that solutions of the initial value problem for steady flows tend to that solution but do not reach it except a specific case of the inlet flow rate. Linear stability analysis shows that steady flows are unstable in regard to perturbations whose velocities are close to the liquid velocity at the solid–liquid interface.
Apparatus for simultaneous stress and weight measurement during film drying in an environmentally controlled chamber
Authors: Fischer Steffen B. , Koos Erin
Published: December 2020

The drying behavior of coatings is essential for the development of formulations in order to obtain reliable and defect free finishes. There are two major measures of interest: the development of the stress responsible for cracking and the drying rate that gives insight into the morphological structure. The cantilever deflection method is the predominant way of determining stresses under defined drying conditions such as temperature and humidity. However, both measures of interest are currently obtained using two different coatings when dried in a chamber or a single coating with simultaneous measurements that can only be dried under ambient conditions. In this paper, we present an apparatus design based on the cantilever deflection method that allows simultaneous measurement of the stress and drying rate in an environmentally controlled chamber.
Modulating the percolation network of polymer nanocomposites for
flexible sensors
Authors: Cao Jie , Zhang Xinxing
Published: December 2020

Flexible sensors have been the focus of intense research efforts in academic and industrial fields for Internet-of-Things applications. In this revolution, different strategies are explored to fabricate flexible tactile sensors by leveraging the pros and cons. In this Perspective, we focus on the current achievements of conductive polymer composites with three bottle-up micro/nano-conductive network structures based on the fundamental tunneling percolation theory and their potentialities and drawbacks for tactile sensor applications. Then, we highlight how model simulations can be used to elucidate the structure and property relationship clearly and guide the modulation of the network structure of conductive composites. Finally, benefiting from the precise definition of the parameters of the composites by model simulation, we discuss the perspectives of the emerging machine learning paradigm on inverse design and development of newly conductive polymer composites in the future.
Himawari-8 Atmospheric Motion Vectors - Operational Generation and Assimilation
Authors: Le Marshall John , Howard David , Xiao Yi , Daniels Jamie , Wanzong Steve , Jung Jim , Bresky Wayne , Bailey Andrew , Tingwell Chris , Le Tan , Margetic Denis
Published: December 2020

In October 2014 the Japanese Meteorological Agency (JMA) launched the new generation geostationary satellite Himawari-8. This satellite provides ten minute imagery in sixteen wavebands over the Asian and Australasian region. The imagery has been navigated, calibrated and subsequently used in the Bureau of Meteorology (BoM) to generate Atmospheric Motion Vectors (AMVs) over the full earth disk viewed from the satellite every ten minutes. Each vector has been error characterised and assigned an expected error. In preparation for the operational assimilation of the ten minute data, these high temporal and spatial resolution data were used with the BoM operational database to provide forecasts from the next generation operational forecast model ACCESS APS2 using 4D Var. Results from these tests indicate these locally generated Himawari-8 ten minute AMVs are of high density and quality and have the potential to improve numerical weather prediction (NWP) model initialisation and forecasts. The forecasts undertaken include cases associated with extreme weather. The results also provided the appropriate times, data selection and application methods for the effective use of these high temporal resolution data. As a result of these studies these wind data were approved for inclusion in the BoMs operational database and are used in operational forecasting.
Latitudinal variations in the accuracy of model-generated forecasts of precipitation over Australia and south-east Asia
Authors: Dare Richard A. , Ebert Elizabeth E.
Published: December 2020

Forecasts of precipitation produced by global and regional versions of the Bureau of Meteorology’s Australian Community Climate and Earth System Simulator (ACCESS) numerical weather prediction models are compared with Tropical Rainfall Measuring Mission (TRMM) observations for the period January 2011 to March 2014. The area considered covers longitudes 110° to 160°E within 40° latitude of the equator, and includes the Australian continent and part of south-east Asia. Forecast accuracy is assessed using objective measures: equitable threat score (ETS), frequency bias (FB), and the ratio of predicted to observed rain volume (RVR). For the assessment, the TRMM and model datasets are both interpolated to consistent grids defined by spacings of 1° longitude and 1° latitude. Assessments based on three-month seasons show that, in general, the volume of rain predicted by the models is too high, and rainfall is predicted to occur at more locations than observed. Latitudinal variations in values of the ETS reveal marked declines over the equatorial tropics, with minimum values near the equator from December to May and near 10°N from June to November. Differences in the ETS between 24-hour model and persistence forecasts show that the models produce useful predictions of rainfall away from the tropics, poleward of latitudes 5º-15º S and 15º-30º N, depending on the season and model. The 48-hour model predictions are more useful than the 24-hour forecasts, with improvements relative to persistence over most latitudes, although differences are close to zero at low latitudes. Varying the rain threshold used to compute skill metrics shows that the models produce excessive rainfall at low rain rates, generally less than approximately 15 mm day-1, while not enough precipitation is forecast at higher rain rates. Values of the ETS are generally highest at lower rain rates, coinciding with the excessive values of RVR and FB.
Persistence of cool conditions after heavy rain in Australia
Authors: Hope Pandora K. , Watterson Ian G.
Published: December 2020

There is a general understanding that heavy rainfall will suppress subsequent near-surface temperatures. However, there have been few studies describing this effect. In this study the top 10 % of monthly rainfall, by season and by grid point over Australia is used to represent extended periods of heavy rainfall (termed 'very wet'). The corresponding daily maximum average monthly temperature (Tmax) during those months are shown to be cooler by at least 0.5 °C almost everywhere across Australia, in every season in both observation-based data and climate models. Cooler than average Tmax conditions are then evident for the following four months in some places, particularly following very wet months in winter. The average monthly daily minimum temperature (Tmin), unlike Tmax, is warmer than average during very wet months in winter,by up to 1.5 °C in the east of the continent in both observations and the model mean. Warmer Tmin conditions are also evident during very wet months in the south-east and across the south of the continent in other seasons, particularly in observations. Tmin is cooler than average in very wet months in summer elsewhere across the continent. In subsequent months, Tmin then tends to be cooler than average. It is suspected that increased cloud during the first month keeps Tmin warm, while wetter soils contribute to cooler Tmin during subsequent months. These results indicate that indeed heavy, extended rainfall can have a cooling influence on subsequent temperature, and, following winter, this can have an effect right through to the following summer. The Tmax anomalies at the end of the century under RCP8.5 are similar to those under the current climate, except in future there are relatively cooler conditions in the south during very wet months in winter and in the month following.
Seasonal climate summary for the southern hemisphere (winter 2016): a strong negative Indian Ocean Dipole brings wet conditions to Australia
Authors: Trewin Blair
Published: December 2020

This is a summary of the southern hemisphere atmospheric circulation patterns and meteorological indices for winter 2016; an account of seasonal rainfall and temperature for the Australian region and the broader southern hemisphere is also provided. One of the strongest negative phases on record of the Indian Ocean Dipole (IOD) developed during the season, contributing to Australia's second wettest winter on record, with rainfall above average over the vast majority of the continent. Neutral conditions prevailed in the tropical Pacific following the end of a strong El Niño event in autumn 2016, but the continuing effect of the 2015-16 El Niño was still evident in southern hemisphere temperatures, which were at or near record high levels.