bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimal velocity prediction for fuel economy improvement of connected vehicles
Authors: Barik Biswajit , Krishna Bhat Pradeep , Oncken Joseph , Chen Bo , Orlando Joshua , Robinette Darrell
Published: September 2018

With the advancement of vehicle‐to‐vehicle and vehicle‐to‐infrastructure technologies, more and more real‐time information regarding traffic and transportation system will be available to vehicles. This paper presents the development of a novel algorithm that uses available velocity bounds and powertrain information to generate an optimal velocity trajectory over a prediction horizon. When utilised by a vehicle, this optimal velocity trajectory reduces fuel consumption. The objective of this optimisation problem is to reduce dynamic losses, required tractive force, and completing trip distance with a given travel time. Sequential quadratic programming method is employed for this nonlinearly constrained optimisation problem. When applied to a GM Volt‐2, the generated velocity trajectory saves fuel compared to a real‐world drive cycle. The simulation results confirm the fuel consumption reduction with the rule‐based mode selection and the energy management strategy of a GM Volt 2 model in Autonomie.
Development of neuro‐fuzzy‐based multimodal mode choice model for commuter in Delhi
Authors: S Minal , Sekhar Ch Ravi , Madhu Errampilli
Published: September 2018

Delhi is highly plagued by traffic congestion and is notoriously known for its traffic jams. Thus, the question of studying the mode‐choice preferences of commuters in Delhi will be integral to travel demand forecasting. The study area poses a challenge in terms of heterogeneity in different types of travel modes available as well as commuters with heterogeneous backgrounds. It offers the typical mix traffic situation prevalent in developing countries, which is cumbersome to model. Eight modes of travel have been considered in this study, which is difficult to come across in previous studies found in the literature. This study proposes to capture mode‐choice preferences of commuters by using an adaptive‐neuro‐fuzzy classifier (ANFC) with linguistic hedges. The proposed mode‐choice model will have improved ‘distinguish‐ability’ in terms of less overlapping amongst classes, so that the prediction ability is highly improved. Artificial neural network, fuzzy‐logic and multinomial‐logit models have also been used for analysing mode‐choice behaviour of commuters in Delhi. This study is based on microdata collected through household survey conducted in the study area. Results depict that mode‐choice model developed by ANFC performs superior to the other models in terms of prediction accuracy.
Hidden Markov model and driver path preference for floating car trajectory map matching
Authors: Song Chengbo , Yan Xuefeng , Stephen Nkyi , Khan Arif Ali
Published: September 2018

Here, a hidden Markov model (HMM) and driver path preference (DPP)‐based algorithm was proposed for floating car trajectory map matching. The algorithm focused on two improvements over existing HMM‐based map matching algorithm: (i) the use of distance difference feature and average speed difference feature for transition probability calculation, which reasonably describe the context information between the two adjacent sampling points. It results in a more accurate matching capability; (ii) the DPP overcomes the shortcoming of feature attenuation in calculating the transition probability at low floating car sampling rates. It assures the matching accuracy of the algorithm at low sampling rates. The algorithm was evaluated using ground truth data and the results of the experiment show that the new transition probability significantly improves the matching capability. The proposed DPP can significantly help to maintain the matching accuracy under the condition of low sampling rates.
Prediction of ship collision risk based on CART
Authors: Li Yishan , Guo Zhiqiang , Yang Jie , Fang Hui , Hu Yongwu
Published: September 2018

The primary function of a collision risk index is to determine the time when ships take action to avoid a collision. In this study, based on the complex non‐linear relationship between the collision risk degree and its influencing factors, classification and regression trees (CARTs) are applied to construct a prediction model for ship collision risk. The fuzzy comprehensive evaluation method is used to evaluate the risk of ship encounter samples to build a collision risk identification library containing expert collision avoidance experience information. The authors’ proposed CART regression model is trained using the samples in this identification library to develop a collision risk prediction model based on the CART. Their experimental results show that their proposed CART prediction model is better that the existing ship collision risk prediction model in terms of prediction accuracy and prediction speed when the feature dimension is low and the sample size is small.
Multinomial logit analysis of the effects of five different app‐based incentives to encourage cycling to work
Authors: Huang Bingyuan , Fioreze Tiago , Thomas Tom , Van Berkum Eric
Published: September 2018

This study presents results from an investigation into the effect of positive incentives on cycling behaviour among 1802 commuters in the Twente region of the Netherlands. The authors used an on‐line survey, which included mock‐up apps with incentives to commute to work by bicycle. They tested five reward schemes, namely social rewards (such as badges), in‐kind gifts, money, competition, and cooperation. They used the survey data in a multinomial logit model to estimate to what extent travellers will use the app and increase their cycling frequency and which incentives they prefer. The model results show that respondents who sometimes cycle to work are more positive about incentive schemes than respondents who never cycle and that offering an app with in‐kind gifts is probably most effective. Interestingly, non‐cyclists are more likely to change their behaviour for a reward if they care about travel costs, while occasional cyclists are more likely to cycle more often in response to incentives if they care about attributes that are related to the cycling itself. This also depends on attitudes towards cycling and on socio‐demographic variables.
Tamanu oil and skin active properties: from traditional to modern cosmetic uses
Authors: Raharivelomanana Phila , Ansel Jean-Luc , Lupo Elise , Mijouin Lily , Guillot Samuel , Butaud Jean-François , Ho Raimana , Lecellier Gaël , Pichon Chantal
Published: September 2018

Calophyllum inophyllum L. (Calophyllaceae), locally called “tamanu” in French Polynesia, is an evergreen pantropical tree growing mostly along the seashores. Its barks, leaves, and fruits are still used in traditional medicine. The oil expressed from the nuts has been also traditionally used. Tamanu oil is topically applied on skins as well as mucous membrane lesions. This oil is especially recommended to heal all kinds of skin ailments. Bioassays and different assessments of Tamanu oil revealed numerous biological activities (antioxidant, anti-inflammatory, antibacterial, wound healing…), so bringing scientific evidence of beneficial effects of this oil on human skin healing. Such biological properties may explain the use of tamanu oil as an active cosmetic ingredient recorded as “Calophyllum inophyllum seed oil” by the INCI (International Nomenclature of Cosmetic Ingredients). Most of the bioactive properties of tamanu oil are attributed to oil composition including the presence of resinous compounds in tamanu oil beside common fatty acids, which constitutes a unique characteristic of this healing oil. Actually, resinous part of tamanu oil is known to contain bioactive secondary metabolites mostly constituted by neoflavonoids including pyranocoumarin derivatives. Herein, chemical constituents and biological properties of tamanu oil are presented with a focus of its traditional use inspiring modern valuations related to cosmetic field.
Cellular layout design using Tabu search, a case study
Authors: Ghassemi Tari Farhad , Ahadi Khatereh
Published: September 2018

This paper presents a facility layout design for a cellular manufacturing system (CMS), with the automated guided vehicles (AGVs) as the transportation device, to minimize the total material handling costs. A new concept of assigning the workstations to the non-overlapping closed zones, by which independent AGVs are allocated for internal transfer of materials/parts in each zone, is proposed. To handle this problem, a mathematical programming model is developed. The problem has been shown to be NP-hard. This computational difficulty has led us to consider suboptimal solutions generated by a Tabu search with three algorithmic variants. To evaluate the efficiencies of these algorithms, an ANOVA statistical test is performed and the best algorithm is designated. The solution of the new algorithms is then compared with the solution obtained by the CPLEX software. The result indicates that the designated algorithm can provide an average solution with a small deviation of only 0.01% from the optimal solution. This algorithm is also applied to a real-world case problem. The use of this algorithm for re-designing of the layout for the real-world case problem shows considerable cost saving comparing to its existing layout design.
Inkontinenz bei Leistungssportlerinnen
Authors: Schulte-Frei Birgit , Jäger Lars
Published: September 2018

Hintergrund Entgegen der Annahme, dass der Beckenboden bei Leistungssportlerinnen besonders stark ist und aufgrund eines überdurchschnittlich guten Körperbewusstseins auch bei extremer Belastung adäquat funktioniert, zeigt eine Vielzahl von Studien, dass Fehlfunktionen des Beckenbodens bei Leistungssportlerinnen ein häufiges Problem darstellt.

Ziel Ziel der vorliegenden Studie war die Darstellung des aktuellen Forschungsstandes, die Enttabuisierung der Thematik Inkontinenz sowie die Darlegung rehabilitativer und präventiver Therapiemethoden.

Methode Für eine Übersicht über den wissenschaftlichen Stand der Problematik wurde eine systematische Literaturrecherche durchgeführt.

Ergebnisse In den 28 zur Untersuchung herangezogenen Artikeln zeigten Kategorien diverser Sportarten unterschiedlich hohe Prävalenzen von Inkontinenz (abhängig von der jeweiligen Sportart: Y bis 70 %). Ursachen hierfür finden sich in Struktur, Trainingssteuerung und -beanspruchung, hormonellem Status sowie der psychischen Verfassung. Diese können nicht nur zeitgleich einwirken, sondern beeinflussen sich auch gegenseitig. Bei ca. 20 % der Athletinnen führt eine Verstärkung der Symptomatik zum Abbruch der sportlichen Karriere und erhöht zudem die Wahrscheinlichkeit, im späteren Leben erneut Inkontinenz zu entwickeln.

Schlussfolgerungen Vor allem bei jungen Sportlerinnen sollte das Tabu Inkontinenz thematisiert werden. Darüber hinaus sollten Trainingsprogramme die Inkontinenz mindernde und Präventivmaßnahmen einschließen. Neben Beckenbodentraining können Hilfsmittel (z. B. Pelvic Trainer) oder mentales Training hilfreich sein.
60plus: Förderfaktoren und Barrieren für die Teilnahme an einem Bewegungsförderungsprogramm
Authors: Eberli-Kappeler Ursula , Nast Irina , Huber Erika , Niedermann Karin
Published: September 2018

Hintergrund Die ältere Bevölkerung einer 100 000 Einwohner zählenden Schweizer Stadt wurde mittels der 3-monatigen Kampagne „60plus-lustvoll mobil“ mit 4 frei wählbaren Angeboten (Vorträge, individuelle Beratung, Gangsicherheits- und Rhythmik-Kurse) auf die Wichtigkeit von körperlicher Aktivität aufmerksam gemacht.

Ziel Das Ziel der hier präsentierten Begleitforschung war die Untersuchung der die Teilnahme an der Kampagne beeinflussenden Faktoren, um für zukünftige ähnliche Kampagnen Empfehlungen zu formulieren.

Methode Die Teilnehmer der verschiedenen Angebote der Kampagne wurden in einer Querschnittsstudie mit einem auf das Angebot zugeschnittenen Fragebogen befragt.

Ergebnisse Die meistgenutzten Angebote waren die individuelle Beratung mit 195 Besuchern (35 % Rücklauf, n = 68) und der Vortrag mit 75 Besuchern (61 % Rücklauf, n = 46). Die häufigsten Förderfaktoren zur Teilnahme umfassten für den Vortrag „Neugierde“ (76 %), für die Beratung „Wunsch, mehr zu wissen“ (64 %), für den Gangsicherheitskurs „Gangsicherheit“ (94 %) und für den Rhythmik-60plus-Kurs „Verbesserung des Gleichgewichts und der Leistungsfähigkeit“ (71 %). Als Barriere für die Nutzung eines anderen Angebots wurde am häufigsten „kein Bedarf“ genannt.

Schlussfolgerung Die Teilnehmer der Kampagne erwiesen sich als neugierig, wollten mehr Wissen erwerben und etwas für ihre Gesundheit tun. Sie bevorzugten mehrheitlich eine individuelle Beratung zur körperlichen Aktivität und nutzten die Kurse spezifisch und problemorientiert. Ihre klaren Titel unterstützten sie darin, das für sie richtige Angebot zu wählen. Auch zukünftige Kampagnen sollten spezifische und problemorientierte Angebote beinhalten.
In den Forschungsethikkommissionen müssen Physiotherapeuten vertreten sein, denn nur so können die Kommissionen lernen, was es heißt, in Physiotherapie zu forschen
Authors: Hummel Alexandra , Klotz Susanne , Porz Rouven
Published: September 2018

Hintergrund Nicht erst die jüngere Geschichte zeigt, dass es bei der Forschung am Menschen ein Spannungsfeld zwischen dem Forschungsinteresse und allgemeingültigen Werten und Normen gibt. Im Zuge der Professionalisierung der Physiotherapie ist daher eine grundlegende Begutachtung ethischer Probleme in der Forschung notwendig.

Ziel Das Ziel der Arbeit war es, ethische Herausforderungen in der Physiotherapieforschung aufzudecken, zu illustrieren und in geeigneter Form zu analysieren.

Methode Zur Beantwortung der Forschungsfrage wurden der qualitative Forschungszugang gewählt und semi-strukturiere Interviews mit Forschenden aus der Physiotherapie und im Bereich der Ethik arbeitenden Personen durchgeführt.

Ergebnisse Ethische Herausforderungen, welche Inhalt der Interviews mit Forschenden aus dem Bereich der Ethik (E) und/oder aus der Physiotherapie (P) waren, sind: gesellschaftlicher Nutzen (E & P), gutes wissenschaftliches Arbeiten (E & P), Auswahl der Probanden (E & P), günstiges Risiko-Nutzen-Verhältnis (E & P), informierte Einwilligung (E & P), Wahrung der Rechte der Teilnehmer (E & P), Physiotherapie als körperliche Praxis (E & P), therapeutisches Missverständnis (E & P) und Einsatz von Placebos und Kontrollgruppen (E & P), externe Überprüfung der Forschung (E), Rekrutierung innerhalb der Berufsgruppe (E), Umgang mit Drop-outs (E), fehlende wissenschaftliche Grundlage (P), qualitätsmindernder Einfluss der Ressourcen auf die Studie (P), Bewusstsein über eigenen Einfluss auf die Studie (P), Aufklärung der Probanden (P) nach Abschluss der Studie über Ergebnisse (P).

Schlussfolgerung Die Wahl des qualitativen Forschungsansatzes erwies sich als sinnvoll, da die ganzheitliche Betrachtung einer Begebenheit im Vordergrund stand. Die Arbeit kann als Grundlage für weitere Forschung dienen.
A Novel Technique to Perform Microvascular Anastomosis Revisions without Clamps
Authors: Harb Amro , Levi Maxwell , Akelina Yelena , Kadiyala Rajendra , Ascherman Jeffrey
Published: September 2018

Background For surgeons learning microsurgery, uneven spacing between sutures while performing microvascular arterial anastomoses is one of the most common technical errors made that can lead to leakage. Based on the previous surgical experience and training of these surgeons, the first option chosen to prevent bleeding is to place a vascular clamp proximal to the anastomosis and an additional suture at the site of the leak. Because this technique may have technical and thrombosis concerns, our study proposes an alternative technique of performing post-anastomotic revisions without the use of clamps.

Methods Our technique involves placing a cotton-tipped applicator under the artery and lifting it to partially occlude flow within the vessel as an additional suture is placed at the leakage site to complete the revision. One-hundred eighty-four microvascular anastomoses were performed on the femoral arteries of 92 Sprague-Dawley rats, and of the 184 anastomoses, 147 had a leak and required a post-anastomotic revision. All revisions were completed using our technique, and no clamps were used during any of the revisions.

Results Of the 147 post-anastomotic revisions completed using our technique, 141 (95.9%) were patent 2 hours post-revision. The mean operating time for the revisions was 5:03 minutes (range, 1:44–6:30 minutes).

Conclusion Our technique of partially occluding an artery with a cotton-tipped applicator while performing a post-anastomotic revision is a safe and effective alternative to using vascular clamps. Our technique may also reduce technical errors and have a low risk of causing thrombosis when completing post-anastomotic revisions.
Understanding walkability and walking rates in Berlin: an urban form and street pattern comparison
Authors: Valera Sosa A. , Nickl-Weller C.
Published: September 2018

Background: This descriptive study provides information indicative of the interaction between physical features of neighbourhood environments with health behaviours such as walking and biking which consequently affect disease rates related to lifestyle. Aim: Through a summary of systematic observations at two urban scales, the macro and mesolevels, a neighbourhood comparison was realized in Berlin, Germany, to explore how urban forms and street patterns can support walking or biking, or not, despite seasonal variations, socio-economic status, cultural backdrop or individual decisions to walk. For this study, a conceptual evaluation framework was conceived and structured to assess secondary data from public databases, conveniently decreasing time and costs. Result: The framework and preliminary results of the work aim to be a significant endeavour in promoting transdisciplinarity among researchers and practitioners mainly from public health, architecture, urban planning and design fields.
Efficient manifolds tracing for planar maps
Authors: Ciro David , Caldas Iberê L. , Viana Ricardo L. , Evans Todd E.
Published: September 2018

In this work, we introduce an exact calculation method and an approximation technique for tracing the invariant manifolds of unstable periodic orbits of planar maps. The exact method relies on an adaptive refinement procedure that prevents redundant calculations occurring in other approaches, and the approximated method relies on a novel interpolation approach based on normal displacement functions. The resulting approximated manifold is precise when compared to the exact one, and its relative computational cost falls like the inverse of the manifold length. To present the tracing method, we obtain the invariant manifolds of the Chirikov-Taylor map, and as an application we illustrate the transition from homoclinic to heteroclinic chaos in the Duffing oscillator that leads from localized chaos to global chaotic motion.
Spectroscopic studies of laser produced plasma of doped nano-structured material by laser induced breakdown spectroscopy
Authors: Farooq Zahid , Ali Raheel , Qurashi Umar Saeed , Mahmood Mian HR , Yaseen Muhammad , Qayyum Muhammad Abdul , Hussain Muhammad Nasir , Shah Syed Mujtaba , Jan Tariq
Published: September 2018

We present the qualitative and quantitative use of laser-induced breakdown spectroscopy (LIBS) for the compositional characterization of the doped material of zinc (Zn) and tin (Sn) nanoparticles. The transition metal zinc doped tin nanoparticles are synthesized via co-precipitation and hydrothermal routes. A single laser operating at a wavelength at 532 nm is used to produce ablated plasma. The detailed analysis of the emission spectrum of ablated plasma reveals qualitative information which can be correlated with identification of the target material. The Boltzmann plot, standard two-line, and Saha-Boltzmann plot methods are used to determine the plasma temperature of nanoparticles, while the Stark broadening method and Saha-Boltzmann equation are used to estimate the electron number density of ablated plasma. Calibration free (CF-LIBS), one line calibration free (OLCF-LIBS), and calibration curve (CC-LIBS) approaches are used for the quantitative analysis of doped nano-structured materials with low and high concentrations. Using CF-LIBS, the quantitative analysis of the sample is carried out using Boltzmann plots, while using calibration based LIBS, quantitative results based on calibration curves are obtained, and limits of detection of nanoparticles are also determined using these calibration curves. Quantitative results estimated from calibration free and calibration based approaches are compared and validated with the results from standard techniques such as laser ablation time of flight (LA-TOF) spectroscopy and EDX. The present work establishes LIBS as an effective analytical tool for qualitative and quantitative estimation of the doped nanomaterials from atomic emission spectra.
X-ray detector based on Mn doped MgAl2O4 and Si photodiode
Authors: Katsumata Toru , Takeuchi Haruna , Komuro Shuji , Aizawa Hiroaki
Published: September 2018

Luminescence properties of Mn doped MgAl2O4 crystals connected with the Si PIN photodiode (PD) have been evaluated for X-ray detector applications. Mn doped MgAl2O4 crystals emit green colored luminescence peaking at around λ = 520 nm with CuKα irradiation. The intensity of the output signal from Si PD increases linearly with the X-ray intensity of CuKα generated with the X-ray tube at a current from 2 mA to 40 mA. The intensity of the X-ray excited luminescence is strongest in the specimen with 3.0 mol. % Mn. Afterglow luminescence is weak in the specimen with 2.0 mol. % Mn. Mn doped MgAl2O4 crystals connected with the Si PD is considered to be a useful X-ray detector.
Can we use time-resolved measurements to get steady-state transport data for halide perovskites?
Authors: Levine Igal , Gupta Satyajit , Bera Achintya , Ceratti Davide , Hodes Gary , Cahen David , Guo Dengyang , Savenije Tom J. , Ávila Jorge , Bolink Henk J. , Millo Oded , Azulay Doron , Balberg Isaac
Published: September 2018

Time-resolved, pulsed excitation methods are widely used to deduce optoelectronic properties of semiconductors, including now also Halide Perovskites (HaPs), especially transport properties. However, as yet, no evaluation of their amenability and justification for the use of the results for the above-noted purposes has been reported. To check if we can learn from pulsed measurement results about steady-state phototransport properties, we show here that, although pulsed measurements can be useful to extract information on the recombination kinetics of HaPs, great care should be taken. One issue is that no changes in the material are induced during or as a result of the excitation, and another one concerns in how far pulsed excitation-derived data can be used to find relevant steady-state parameters. To answer the latter question, we revisited pulsed excitation and propose a novel way to compare between pulsed and steady state measurements at different excitation intensities. We performed steady-state photoconductivity and ambipolar diffusion length measurements, as well as pulsed time-resolved microwave conductivity and time-resolved photoluminescence measurements as a function of excitation intensity on the same samples of different MAPbI3 thin films, and found good quasi-quantitative agreement between the results, explaining them with a generalized single level recombination model that describes the basic physics of phototransport of HaP absorbers. Moreover, we find the first experimental manifestation of the boundaries between several effective recombination regimes that exist in HaPs, by analyzing their phototransport behavior as a function of excitation intensity.
From billiards to thermodynamic laws: Stochastic energy exchange model
Authors: Li Yao , Bu Lingchen
Published: September 2018

This paper studies a billiards-like microscopic heat conduction model, which describes the dynamics of gas molecules in a long tube with thermalized boundary. We numerically investigate the law of energy exchange between adjacent cells. A stochastic energy exchange model that preserves these properties is then derived. We further numerically justified that the stochastic energy exchange model preserves the ergodicity and the thermal conductivity of the original billiard model.
Solid-immersion metalenses for infrared focal plane arrays
Authors: Zhang Shuyan , Soibel Alexander , Keo Sam A. , Wilson Daniel , Rafol Sir. B. , Ting David Z. , She Alan , Gunapala Sarath D. , Capasso Federico
Published: September 2018

Optical components based on metasurfaces (metalenses) offer an alternative methodology for microlens arrays. In particular, metalens arrays have the potential of being monolithically integrated with infrared focal plane arrays (IR FPAs) to increase the operating temperature and sensitivity of the latter. In this work, we demonstrate a type of transmissive metalens that focuses the incident light (λ = 3–5 μm) on the detector plane after propagating through the substrate, i.e., solid-immersion type of focusing. The metalens is fabricated by etching the backside of the detector substrate material (GaSb here), making this approach compatible with the architecture of back-illuminated FPAs. In addition, our designs work for all incident polarizations. We fabricate a 10 × 10 metalens array that proves the scalability of this approach for FPAs. In the future, these solid-immersion metalenses arrays will be monolithically integrated with IR FPAs.
Sliding planar conjoined cut-wire-pairs: A novel approach for splitting and controlling the absorption spectra
Authors: Al-Badri Khalid Saeed Lateef , Karacan Nezihe , Kucukoner Elif Merve , Ekmekci Evren
Published: September 2018

In this study, vertical sliding of conjoined cut-wire-pairs (CCWPs) over the substrate plane is demonstrated to split the absorption peak into two, with a reasonable decrease in the absorption peak, while providing the flexibility of controlling the locations of the absorption peaks by the use of sliding (i.e., shift) amount s in the S-band. In the design, the CCWP structure simply turns into a square patch absorber with a single perfect absorption peak when s = 0. For the proof of concept, the CCWPs having s = 0, 0.5, 1.0, 1.5, and 2.0 mm are fabricated and the absorption spectra are measured. The experimental results agree very well with the simulation results. Moreover, the absorption mechanism is investigated considering the clockwise rotated CCWP and the counterclockwise rotated CCWP structures. It is significant to state that the CCWP design may take place in plenty of applications such as sensing, obtaining dual/multi-band or broadband of absorption, and switching/tuning the absorption spectra.
Dislocation baskets in thick InxGa1−xN epilayers
Authors: Wang Shuo , Xie Hongen , Liu Hanxiao , Fischer Alec M. , McFavilen Heather , Ponce Fernando A.
Published: September 2018

Dislocation clusters have been observed in thick InxGa1−xN films with 0.07 ≤ x ≤ 0.12. The clusters resemble baskets with a higher indium content at their interior. Threading dislocations at the basket boundaries are of the misfit edge type, and their separation is consistent with misfit strain relaxation due to the difference in indium content between the baskets and the surrounding matrix. The interior of the base of the baskets exhibits no observable dislocations connecting the threading dislocations, and often no net displacements like those due to stacking faults. We argue that the origin of these threading dislocation arrays is associated with misfit dislocations at the basal plane that dissociate, forming stacking faults. And when the stacking faults form simultaneously satisfying the crystal symmetry, the sum of their translation vectors add up to a lattice vector, or equivalently to no change in the stacking sequence, which is consistent with our observations.
Manipulating reflected acoustic wave via Helmholtz resonators with varying-length extended necks
Authors: Guo Jingwen , Zhang Xin , Fang Yi , Fattah Ryu
Published: September 2018

In this work, we develop a deep subwavelength metasurface which is capable of reflected wave manipulation arbitrarily. Each unit cell of the metasurface is constructed of a Helmholtz resonator with an extended neck. The possibility of creating a phase shift offered by different unit cells is analytically explored based on characteristic mode analysis and demonstrated by the finite element method. It is found that the phase shift of the reflected wave ranging from 0 to 2π in a supercell (consists of eight inhomogeneous unit cells) can be engineered by tuning the length of the extended neck. A periodical array of the supercell is used to construct the designed metasurface. The reflection performance of the proposed metasurface is investigated both numerically and experimentally, and good agreement is achieved. Anomalous phenomena such as converting an incident wave to a surface wave and negative reflection are demonstrated using the designed metasurface. The key features of the proposed metasurface are the thin thickness ≈λ/30 (λ is the operation wavelength), simple configuration, and easy fabrication, making it possess a promising potential in miniaturization and integration in acoustic devices.
Defects in h-BN tunnel barrier for local electrostatic probing of two dimensional materials
Authors: Liu Ying , Tan Zhenbing , Kumar Manohar , Abhilash T. S. , Liu Guan-jun , Hakonen Pertti
Published: September 2018

Defects in the hexagonal boron nitride (h-BN) layer can facilitate the tunneling current through thick h-BN tunneling barriers. We have investigated such current-mediating defects as local probes for materials in two dimensional heterostructure stacks. Besides IV characteristics and negative differential conductance, we have characterized the electrical properties of h-BN defects in vertical graphene-h-BN-Cr/Au tunnel junctions in terms of low frequency current noise. Our results indicate a charge sensitivity of 1.5×10−5 e/Hz at 10 Hz, which is equal to good metallic single electron transistors. The noise spectra at low frequency are governed by a few two-level fluctuators. For variations in the electrochemical potential, we achieve a sensitivity of 0.8 μeV/Hz.
Study of the thrust–drag balance with a swimming robotic fish
Authors: Gibouin Florence , Raufaste Christophe , Bouret Yann , Argentina Médéric
Published: September 2018

A robotic fish is used to test the validity of a simplification made in the context of fish locomotion. With this artificial aquatic swimmer, we verify that the momentum equation results from a simple balance between a thrust and a drag that can be treated independently in the small amplitude regime. The thrust produced by the flexible robot is proportional to A2f2, where A and f are the respective tail-beat amplitude and oscillation frequency, irrespective of whether or not f coincides with the resonant frequency of the fish. The drag is proportional to U02, where U0 is the swimming velocity. These three physical quantities set the value of the Strouhal number in this regime. For larger amplitudes, we found that the drag coefficient is not constant but increases quadratically with the fin amplitude. As a consequence, the achieved locomotion velocity decreases, or the Strouhal number increases, as a function of the fin amplitude.
Exploring deep defect state impact on open circuit voltage of conventional and inverted organic solar cells
Authors: Rana Aniket , Kumar Amit , Chand Suresh , Singh Rajiv K.
Published: September 2018

In this manuscript, conventional and inverted organic solar cells based on P3HT:PC[60]BM have been explored to understand the effect of deep defect states on the open circuit voltage. The enhancement in the open circuit voltage in the inverted structure compared to the conventional structure has been comprehensively discussed in terms of density of defect states. To comply with the investigation, DC and AC measurements (impedance spectroscopy) at various temperatures have been performed extensively. Enhancement in open circuit voltage at low temperature is observed which is described by the shifting of hole and electron quasi-Fermi levels. The important observation from the defect density of states profile is that the center of Gaussian distribution is shifted to high energy as the temperature is increased which is an indication of the creation of shallow traps in polymers. In the inverted device, the disorder parameter (σ) is 33 meV, whereas in the conventional device it becomes 75 meV. This implies that the energetic disorder is reduced in an inverted device which helps in the improvement of open circuit voltage.
Tailoring ferroic domains by introducing internal stress: Fe81Ga19 magnetostrictive alloy as an example
Authors: Chen Yijun , Wang Jingmin , Jiang Chengbao
Published: September 2018

Ferroic materials, including ferromagnets, ferroelectrics, and ferroelastics, can output strain via domain reversal stimulated by external fields. However, domains with multiple orientations generally form in ferroic materials, resulting in a small value of output strain. Tailoring the preferential orientation of ferroic domains is important for realizing large strain. In this work, taking Fe81Ga19 magnetostrictive alloys as an example, the preferential orientation of magnetic domains was realized by introducing unidirectional internal stress during single crystal growth. As a result, a large magnetostriction of 300 ppm which was close to the theoretical value of the Fe81Ga19 alloy was obtained from the single crystal without the application of bias pre-stress. After 106 magnetization cycles, the magnetostriction was unchanged, exhibiting high stability. This work may supply an effective approach to tailor ferroic domains towards large strain and some other physical effects in ferroic materials.
A versatile apparatus for fermionic lithium quantum gases based on an interference-filter laser system
Authors: Gänger Benjamin , Phieler Jan , Nagler Benjamin , Widera Artur
Published: September 2018

We report on the design and construction of a versatile setup for experiments with ultracold lithium (Li) gases. We discuss our methods to prepare an atomic beam and laser cool it in a Zeeman slower and a subsequent magneto-optical trap, which rely on established methods. We focus on our laser system based on a stable interference-filter-stabilized, linear-extended-cavity diode laser, so far unreported for lithium wavelengths. Moreover, we describe our optical setup to combine various laser frequencies for cooling, manipulation, and detection of Li atoms. We characterize the performance of our system preparing degenerate samples of Li atoms via forced evaporation in a hybrid crossed-beam optical-dipole trap plus confining magnetic trap. Our apparatus allows one to produce quantum gases of N ≈ 105…106 fermionic lithium-6 atoms at nanokelvin temperatures in cycle times below 10 s. Our optical system is particularly suited to study the dynamics of fermionic superfluids in engineered optical potentials.
Ferroelectric transitions and relaxor behavior in Ba4Sm2(Ti1-xZrx)4Ta6O30 tungsten bronze ceramics
Authors: Feng Wen Bin , Zhu Xiao Li , Liu Xiao Qiang , Chen Xiang Ming
Published: September 2018

Ferroelectric transitions of Ba4Sm2(Ti1-xZrx)4Ta6O30 (x = 0, 0.1, 0.3, 0.5, 0.7, 1) tetragonal tungsten bronze ceramic samples were investigated systematically with the crystal structure, dielectric properties, and Raman vibrations. For x = 0 and x = 0.1, the tetragonal tungsten bronze structure with space group P4bm was determined. A first order ferroelectric transition with a sharp, frequency independent dielectric permittivity maximum was indicated for x = 0 and x = 0.1, while a strong low temperature dielectric relaxation was also determined for x = 0.1. For x = 0.3, 0.5, 0.7, and 1, a tetragonal tungsten bronze structure with space group P4/mbm was determined. Relaxor ferroelectric behavior with strong frequency dispersion becomes dominating for compositions of x ≥ 0.3. Compositions of x = 0 and 0.1 exhibited nonlinear polarization electric-field (P-E) hysteresis loops at room temperature, while other compositions only exhibited linear curves. Raman spectra presented distinct vibration modes for x = 0 and x = 1, and the intensity of some modes showed sudden rising or falling with increasing x from x = 0 to x = 0.1. The abrupt change from normal ferroelectric to relaxor behavior at x = 0.1 in this system is quite different from the gradual change in the Ba4Sm2Zr4(NbxTa1-x)6O30 system, and both the different electron configuration and ion size mismatch between Zr and Ti should play important roles in the crossover here.
Plasmon resonant amplification of hot electron-driven photocatalysis
Authors: Shen Lang , Gibson George N. , Poudel Nirakar , Hou Bingya , Chen Jihan , Shi Haotian , Guignon Ernest , Cady Nathaniel C. , Page William D. , Pilar Arturo , Cronin Stephen B.
Published: September 2018

We report plasmon resonant excitation of hot electrons in a metal based photocatalyst in the oxygen evolution half reaction in aqueous solution. Here, the photocatalyst consists of a 100-nm thick Au film deposited on a corrugated silicon substrate. In this configuration, hot electrons photoexcited in the metal are injected into the solution, ultimately reversing the water oxidation reaction (O2 + 4H+ + 4e− ⇋ 2H2O) and producing a photocurrent. In order to amplify this process, the gold electrode is patterned into a plasmon resonant grating structure with a pitch of 500 nm. The photocurrent (i.e., charge transfer rate) is measured as a function of incident angle using 633 nm wavelength light. We observe peaks in the photocurrent at incident angles of ±9° from normal when the light is polarized parallel to the incident plane (p-polarization) and perpendicular to the lines on the grating. Based on these peaks, we estimate an overall plasmonic gain (or amplification) factor of 2.1× in the charge transfer rate. At these same angles, we also observe sharp dips in the photoreflectance, corresponding to the condition when there is wavevector matching between the incident light and the plasmon mode in the grating. No angle dependence is observed in the photocurrent or photoreflectance when the incident light is polarized perpendicular to the incident plane (s-polarization) and parallel to the lines on the grating. Finite difference time domain simulations also predict sharp dips in the photoreflectance at ±9°, and the electric field intensity profiles show clear excitation of a plasmon-resonant mode when illuminated at those angles with p-polarized light.
A generalized Grad-Shafranov equation with plasma flow under a conformal coordinate transformation
Authors: Kuiroukidis A. , Kaltsas D. , Throumoulopoulos G. N.
Published: September 2018

We employ a conformal mapping transformation to solve a generalized Grad-Shafranov equation with incompressible plasma flow of arbitrary direction and construct particular up-down asymmetric D-shaped and diverted tokamak equilibria. The proposed method can also be employed as an alternative quasi-analytic method to solving two dimensional elliptic partial differential equations.
Mean field phase synchronization between chimera states
Authors: Andrzejak Ralph G. , Ruzzene Giulia , Malvestio Irene , Schindler Kaspar , Schöll Eckehard , Zakharova Anna
Published: September 2018

We study two-layer networks of identical phase oscillators. Each individual layer is a ring network for which a non-local intra-layer coupling leads to the formation of a chimera state. The number of oscillators and their natural frequencies is in general different across the layers. We couple the phases of individual oscillators in one layer to the phase of the mean field of the other layer. This coupling from the mean field to individual oscillators is done in both directions. For a sufficient strength of this inter-layer coupling, the phases of the mean fields lock across the two layers. In contrast, both layers continue to exhibit chimera states with no locking between the phases of individual oscillators across layers, and the two mean field amplitudes remain uncorrelated. Hence, the networks’ mean fields show phase synchronization which is analogous to the one between low-dimensional chaotic oscillators. The required coupling strength to achieve this mean field phase synchronization increases with the mismatches in the network sizes and the oscillators’ natural frequencies.
Kirigami brings new dimensions of cutting-edge nanophotonics to ion beam patterning
Authors: Majors J. H.
Published: September 2018

When adapted to make use of the inherent effects of focused ion beam systems for nanoscale patterning, kirigami offers a wholly new approach to creating photonic devices with unique characteristics.
N,N-Dialkyl-N′-Chlorosulfonyl Chloroformamidines in Heterocyclic Synthesis. Part XV. Some Unexpected Reactions with Anilines
Authors: Innes Dylan , Perkins Michael V. , Liepa Andris J. , Francis Craig L.
Published: September 2018

N,N-Dimethyl-N′-chlorosulfonyl chloroformamidine 1a underwent reactions with various anilines. In addition to the benzo[e][1,2,4]thiadiazine dioxides 8, from 1,3-NCC bis-nucleophilic substitution and bis-anilino adducts 9, some unexpected products were formed, particularly when sterically hindered or electron-poor anilines were used. In these cases, products such as the [1,3,2,4,6]dithiatriazine 1,1,3,3-tetraoxides 17 and, on occasion, N,N,5-trimethyl-4-(arylimino)-4,5-dihydro-[1,3,5]triazin-2-amines 14 were produced in significant yields. Reaction of dichloride 1a with 3-bromoaniline afforded the unusual eight-membered-ring product 2,6-bis(3-bromophenyl)-3,7-bis(dimethylamino)-2H,6H-[1,5,2,4,6,8]dithiatetrazocine 1,1,5,5-tetraoxide 28, in addition to the dithiatriazine tetraoxide 17k. These uncommon heterocyclic structures are of interest for bioactive molecule discovery screening programs.
Topological localization in out-of-equilibrium dissipative systems
Authors: Dasbiswas Kinjal , Mandadapu Kranthi K. , Vaikuntanathan Suriyanarayanan
Published: September 2018

Significance

Topological insulators and their analogs in mechanical materials support conducting states only on their surface. We show that such topologically protected edge modes can also occur as the steady states of classical systems driven out of equilibrium. As proof of principle of the generic applicability of such notions, we show the existence of topologically localized states in a collection of interacting particles described by a hydrodynamic theory and discuss a general procedure to establish them in stochastic networks. In both cases, dissipative processes that break time-reversal symmetry are key to topological protection. Our results provide design principles for robust edge modes in synthetic systems as well as for the localization of flow of matter and information in biology.
Dendritic actin delivery service
Authors: Pai Yun-Jin , Moore Adrian W.
Published: September 2018

The mechanisms by which the actin cytoskeleton regulates dendritic branching are not fully understood. Nithianandam and Chien (2018. J. Cell Biol. https://doi.org/10.1083/jcb.201711136) discover actin blobs, new structures that mediate dynamic actin delivery within a growing dendrite arbor and that mark sites of future branch formation.
Consulting Activities of Agricultural Economists and Response to University Policies
Authors: Conley Kelsey L. , Lusk Jayson L. , Parcell Joe L. , Tonsor Glynn T.
Published: September 2018

A perk of academic employment is the ability to earn additional income from non‐university entities by consulting. Despite the availability of such work, the potential synergies with research, teaching, and extension, and the controversy sometimes surrounding it, there is surprisingly little research on the prevalence of outside consulting, the determinants of consulting, or the response of faculty to specific university consulting policies. To address these issues, this paper utilizes data from a nationwide survey of academic agricultural economists. We find that about 43% of the sample reported consulting activities in the year prior to the survey. Of those who consulted, 12% (or about $34,000) of their total household income on average comes from outside consulting activities. Income from consulting is positively correlated with having a research appointment, income earned from the university, and number of career published papers. We also document extensive heterogeneity across university consulting policies and perceptions of these policies.
Spatial Renewable Resource Extraction under Possible Regime Shift
Authors: Costello Christopher , Nkuiya Bruno , Quérou Nicolas
Published: September 2018

How will countries harvesting mobile natural resources react to the possibility of regime shift? We address the non‐cooperative exploitation of a migratory renewable resource in the presence of possible regime shift that affects its movement. Motivated by the anticipated effects of climate change, we model a regime shift that will alter the spatial movement patterns of the resource at some point in the future. We develop a stochastic spatial bioeconomic model to address the effects of this class of regime shift on non‐cooperative harvest decisions made by decentralized owners such as countries exploiting a migratory fish or other natural resource stock. We find that the threat of a future shift modifies the standard “golden rule”, and may induce more aggressive harvest everywhere, irrespective of whether the owner will be advantaged or disadvantaged by the shift. We also identify conditions under which the threat of regime shift induces owners to reduce harvest rates in advance of the shift. Our analysis suggests that different property rights structures (single ownership vs common property) or heterogeneous growth can give rise to previously unexplored incentives and can even reverse conventional wisdom about how countries will react to the prospect of future environmental change.
Impact of Fractional Ablative Carbon Dioxide Laser on the Treatment of Rhinophyma
Authors: Amaral Maine Trece de Siqueira Santos do , Haddad Alessandra , Nahas Fabio Xerfan , Juliano Yara , Ferreira Lydia Masako
Published: September 2018

Background

Rhinophyma results in nasal deformity, which may lead to significant distress, embarrassment, social isolation, and low self-esteem. Fractional carbon dioxide (CO2) laser treatment is a simple, noninvasive, outpatient procedure with a low complication rate that has proved useful in rhinophyma treatment.

Objectives

The aim of this study was to assess the impact of fractional ablative CO2 laser treatment on self-esteem in patients with rhinophyma.

Methods

Twelve patients with rhinophyma, between 50 and 80 years of age, received 4 monthly treatment sessions with a fractional ablative CO2 laser. The laser parameters were chosen based on the severity of the condition of each patient. Patient satisfaction was assessed through a study-specific questionnaire administered 1 month after treatment. Self-esteem was assessed by the Rosenberg Self-Esteem (RSE) Scale, which was administered before treatment, and at 1, 6, and 12 months after treatment.

Results

A decrease in RSE scores was observed in the post-treatment period, indicating an improvement in self-esteem among patients. All patients were satisfied with the aesthetic results and would recommend the treatment to a friend.

Conclusions

Fractional ablative CO2 laser treatment is associated with high levels of rhinophyma patient satisfaction, and significant improvements in self-esteem.

Level of Evidence: 4