bluuebunny/crossref_metadata_2025_split huggingface dataset:
Axial p‐n junction design and characterization for InP nanowire array solar cells
Authors: Gao Qian , Li Ziyuan , Li Li , Vora Kaushal , Li Zhe , Alabadla Ahmed , Wang Fan , Guo Yanan , Peng Kun , Wenas Yesaya C. , Mokkapati Sudha , Karouta Fouad , Tan Hark Hoe , Jagadish Chennupati , Fu Lan 
Published: November 2018

AbstractIn this work, InP nanowire (NW) array solar cells with different axial p‐i‐n junction designs were investigated. The optical properties of the different NW structures were characterized through a series of microphotoluminescence measurements to extract important material parameters such as minority carrier lifetimes and internal quantum efficiencies. A glancing angle sputtering deposition technique has been developed to enable a direct visualization of the p‐n junctions in the vertical array of InP NW solar cells (NWSCs) using electron beam‐induced current (EBIC) technique. Based on EBIC and electrical simulation, it is found that the background doping in NWSC significantly affects the junction position. By modifying the junction design, the width and position of the p‐n junction can be varied effectively. By employing a p‐p−‐n structure, a high junction position (>1 μm from the substrate) and wide depletion width have been achieved as confirmed by EBIC measurement. Moreover, the NW growth substrate does not show any influence on the device behavior due to the fully decoupled junction position, indicating a promising structural design for future development of high‐performance, low‐cost flexible NW devices.
Designing a hybrid thin‐film/wafer silicon triple photovoltaic junction for solar water splitting
Authors: Perez‐Rodriguez Paula , Vijselaar Wouter , Huskens Jurriaan , Stam Machiel , Falkenberg Michael , Zeman Miro , Smith Wilson , Smets Arno H.M. 
Published: November 2018

AbstractSolar fuels are a promising way to store solar energy seasonally. This paper proposes an earth‐abundant heterostructure to split water using a photovoltaic‐electrochemical device (PV‐EC). The heterostructure is based on a hybrid architecture of a thin‐film (TF) silicon tandem on top of a c‐Si wafer (W) heterojunction solar cell (a‐Si:H (TF)/nc‐Si:H (TF)/c‐Si(W)) The multijunction approach allows to reach enough photovoltage for water splitting, while maximizing the spectrum utilization. However, this unique approach also poses challenges, including the design of effective tunneling recombination junctions (TRJ) and the light management of the cell. Regarding the TRJs, the solar cell performance is improved by increasing the n‐layer doping of the middle cell. The light management can be improved by using hydrogenated indium oxide (IOH) as transparent conductive oxide (TCO). Finally, other light management techniques such as substrate texturing or absorber bandgap engineering were applied to enhance the current density. A correlation was observed between improvements in light management by conventional surface texturing and a reduced nc‐Si:H absorber material quality. The final cell developed in this work is a flat structure, using a top absorber layer consisting of a high bandgap a‐Si:H. This triple junction cell achieved a PV efficiency of 10.57%, with a fill factor of 0.60, an open‐circuit voltage of 2.03 V and a short‐circuit current density of 8.65 mA/cm2. When this cell was connected to an IrOx/Pt electrolyser, a stable solar‐to‐hydrogen (STH) efficiency of 8.3% was achieved and maintained for 10 hours.
A structured Solar System satellite relay constellation network topology design for Earth‐Mars deep space communications
Authors: Wan Peng , Zhan Yafeng 
Published: November 2018

SummaryThe deep space exploration missions require high quality of communication performance between the Earth stations and various deep space explorers, such as Mars orbiters and rovers. Due to the difficulties on improving the point‐to‐point physical wireless link capacity, it is necessary to study the relay network communications under the structured idea. In this paper, the structured Solar System satellite relay constellation network is proposed for Earth‐Mars deep space communications, including the mission background, mathematic model, topology design, and performance analysis. The satellite relay constellation could be modelled as a 2‐dimensional structure with multiple concentric circle loops and multiple relate satellites on each loop. With the different optimal objectives as shortest path, minimum hops and minimum nodes required under the constraint threshold distance for each hop, both the Monte Carlo method and modified Shortest Path First algorithms are studied to work out the optimal network topology designs. Simulation results show that, our network topology design could satisfy the requirements on continuous dual‐directional end‐to‐end communications between the Earth and Mars over the whole mission life period and guarantee the performance of end‐to‐end multihop links above the lowest boundary.
Early childhood science interest development: Variation in interest patterns and parent–child interactions among low‐income families
Authors: Pattison Scott A. , Dierking Lynn D. 
Published: November 2018

AbstractFostering interest in science is critical for broadening engagement with science topics, careers, and hobbies. Research suggests that these interests begin to form as early as preschool and have long‐term implications for participation and learning. However, scholars have only speculated on the processes that shape interest development at this age, when children’s exposure to science primarily occurs during family‐based learning experiences. Moving beyond speculation, we conducted a qualitative study with seven low‐income mothers and their four‐year‐old daughters from Head Start to (a) develop a descriptive understanding of science‐related interest development for preschool children from traditionally underserved communities and (b) identify differences across families that might explain the variation in children’s interests. The study was conducted over 5 months and included two in‐depth interviews and four videotaped sessions in which families engaged in science‐related activities. Interviews suggested that children’s science‐related interests sparked by the sessions fell along a continuum, fromfocusedinterests specific to the materials provided during the sessions tobroadinterests extending to more general topics and activity types. We also found important variation across families related to mothers’ expression of affect, their involvement and leadership styles, and their approach to re‐engaging children when they lost interest or changed focus.
An Efficient Protocol for the Synthesis of 1, 5‐ disubstituted Tetrazole Derivatives via a TMS‐N3 Based Ugi Reaction and their Anti‐cancer Activity
Authors: Gohel Jyoti N. , Lunagariya Kaushikkumar S. , Kapadiya Khushal M. , Khunt Ranjan C. 
Published: November 2018

AbstractIn current research scenario, an efficient synthesis has been developed for novel tetrazole scaffolds by single step multicomponent reaction. One of the most promising pathways is Ugi multi‐component process for the coupling of four different components in a single reaction step and isolate lead molecule which may serve better life to the society. The syntheses of tetrazoles were undertaken by the Ugi‐Multi Component approach with the condensation of aromatic aldehyde containing active pharmacophore, various aryl amines, isocyanide (cyclohexyl isocyanide) and TMS‐N3 under catalyst free reaction condition at room temperature. The structural conformation were carried out by most acceptable spectroscopic technique i.e. MS, IR, NMR and single crystal study (XRD) and potency of compounds (4a to 4h) were checked at NIH (National Institute of Health) use 60 different cell‐lines with respect to nine cancer panels among which compounds 4a and 4b have been found to be more potent against different cell lines.
Approaching Green BPM characterisation
Authors: Hernández González Anaisa , Calero Coral , Pérez Parra Dianelys , Mancebo Javier 
Published: November 2018

AbstractSustainable development is a type of development that meets the needs of the present without compromising the ability of future generations to meet their own needs. Sustainability has recently become more and more important for businesses. This has led to what is known as Green BPM (Green business process management), in which sustainability is considered to be a business objective. The objective of this work was to carry out a systematic literature review in order to evaluate how the subject of Green BPM has evolved and how the term “Green BPM” has been conceptualised so as to propose a new definition compiled from those previously formulated; identify the impact of the incorporation of Green aspects into the BPM life cycle stages; and discover the impact of Green BPM research efforts by means of the PDCA (plan‐do‐check‐act) model, thus identifying (1) the goals that have been proposed when Green initiatives are carried out in BPM, (2) the context in which this has been applied, and (3) the performance indicators considered. Finally, we propose a new characteristic, Process Greenability, together with its subcharacteristics, in addition to identifying the relationship between these subcharacteristics and the indicators identified to make them measurable.
Controlled Leaching Derived Synthesis of Atomically Dispersed/Clustered Gold on Mesoporous Cobalt Oxide for Enhanced Oxygen Evolution Reaction Activity
Authors: Youk Sol , Hwang Jongkook , Lee Seonggyu , Kim Min Su , Lee Jinwoo 
Published: November 2018

AbstractThe water splitting for hydrogen energy is largely constrained by sluggish anodic oxygen evolution reaction (OER). Cobalt oxide, one of the most promising non‐noble metal catalysts for OER, can exhibit highly enhanced catalytic OER activity when deposited on gold substrates. However, it still remains challenging to develop efficient Au/Co3O4 catalysts that can maximize the catalytic activity with the minimum use of gold. Here is reported a simple leaching derived synthesis of atomically dispersed/clustered gold on mesoporous cobalt oxides as highly efficient catalysts for OER. With greatly lowered gold contents <1 wt%, the catalyst shows twice as much current density and Au normalized activity than mesoporous cobalt oxide at 400 mV overpotential. The present work provides a simple synthesis route toward atomically dispersed/clustered gold supported catalysts, which can be extended to the development of a wide variety of efficient nanocatalysts that can be designed for specific applications.
Wind turbine gearbox failure and remaining useful life prediction using machine learning techniques
Authors: Carroll James , Koukoura Sofia , McDonald Alasdair , Charalambous Anastasis , Weiss Stephan , McArthur Stephen 
Published: November 2018

AbstractThis research investigates the prediction of failure and remaining useful life (RUL) of gearboxes for modern multi‐megawatt wind turbines. Failure and RUL are predicted through the use of machine learning techniques and large amounts of labelled wind turbine supervisory control and data acquisition (SCADA) and vibration data. The novelty of this work stems from unprecedented access to one of the world's largest wind turbine operational and reliability databases, containing thousands of turbine gearbox failure examples and complete SCADA and vibration data in the build up to those failures. Through access to that data, this paper is unique in having enough failure examples and data to draw the conclusions detailed in the remainder of this abstract.This paper shows that artificial neural networks provide the most accurate failure and RUL prediction out of three machine learning techniques trialled. This work also demonstrates that SCADA data can be used to predict failure up to a month before it occurs, and high frequency vibration data can be used to extend that accurate prediction capability to 5 to 6 months before failure. This paper demonstrates that two class neural networks can correctly predict gearbox failures between 72.5% and 75% of the time depending on the failure mode when trained with SCADA data and 100% of the time when trained with vibration data. Data trends in the build up to failure and weighting of the SCADA data inputs are also provided. Lastly, this work shows how multi‐class neural networks demonstrate more potential in predicting gearbox failure when trained with vibration data as opposed to training with SCADA data.
Instability wave–streak interactions in a high Mach number boundary layer at flight conditions
Authors: Paredes Pedro , Choudhari Meelan M. , Li Fei 
Published: November 2018

The interaction of stationary streaks undergoing non-modal growth with modally unstable instability waves in a high Mach number boundary-layer flow is studied using numerical computations. The geometry and flow conditions are selected to match a relevant trajectory location from the ascent phase of the HIFiRE-1 flight experiment; namely, a $7^{\circ }$ half-angle, circular cone with $2.5$ mm nose radius, free-stream Mach number equal to $5.30$, unit Reynolds number equal to $13.42~\text{m}^{-1}$ and wall-to-adiabatic temperature ratio of approximately $0.35$ over most of the vehicle. This paper investigates the nonlinear evolution of initially linear optimal disturbances that evolve into finite-amplitude streaks, followed by an analysis of the modal instability characteristics of the perturbed, streaky boundary-layer flow. The investigation is performed with a stationary, full Navier–Stokes equations solver and the plane-marching parabolized stability equations (PSE), in conjunction with partial-differential-equation-based planar eigenvalue analysis. The overall effect of streaks is to reduce the peak amplification factors of instability waves, indicating a possible downstream shift in the onset of laminar–turbulent transition. The present study confirms previous findings that the mean-flow distortion of the nonlinear streak perturbation reduces the amplification rates of the Mack-mode instability. More importantly, however, the present results demonstrate that the spanwise varying component of the streak can produce a larger effect on the Mack-mode amplification. The analysis of planar and oblique Mack-mode waves modulated by the presence of the streaks shows that the planar Mack mode still dominates the instability characteristics of the flow. The study with selected azimuthal wavenumbers for the stationary streaks reveals that a wavenumber of approximately $1.4$ times larger than the optimal wavenumber is more effective in stabilizing the planar Mack-mode instabilities. In the absence of unstable first-mode waves for the present cold-wall condition, transition onset is expected to be delayed until the peak streak amplitude increases to nearly 35 % of the free-stream velocity, when intrinsic instabilities of the boundary-layer streaks begin to dominate the transition process. For streak amplitudes below that limit a significant net stabilization is achieved, yielding a potential transition delay that can exceed 100 % of the length of the laminar region in the uncontrolled case.
Generalized slip condition over rough surfaces
Authors: Zampogna Giuseppe A. , Magnaudet Jacques , Bottaro Alessandro 
Published: November 2018

A macroscopic boundary condition to be used when a fluid flows over a rough surface is derived. It provides the slip velocity $\boldsymbol{u}_{S}$ on an equivalent (smooth) surface in the form $\boldsymbol{u}_{S}=\unicode[STIX]{x1D716}{\mathcal{L}}\boldsymbol{ : }{\mathcal{E}}$, where the dimensionless parameter $\unicode[STIX]{x1D716}$ is a measure of the roughness amplitude, ${\mathcal{E}}$ denotes the strain-rate tensor associated with the outer flow in the vicinity of the surface and ${\mathcal{L}}$ is a third-order slip tensor arising from the microscopic geometry characterizing the rough surface. This boundary condition represents the tensorial generalization of the classical Navier slip condition. We derive this condition, in the limit of small microscopic Reynolds numbers, using a multi-scale technique that yields a closed system of equations, the solution of which allows the slip tensor to be univocally calculated, once the roughness geometry is specified. We validate this generalized slip condition by considering the flow about a rough sphere, the surface of which is covered with a hexagonal lattice of cylindrical protrusions. Comparisons with direct numerical simulations performed in both laminar and turbulent regimes allow us to assess the validity and limitations of this condition and of the mathematical model underlying the determination of the slip tensor ${\mathcal{L}}$.
Strong wave–mean-flow coupling in baroclinic acoustic streaming
Authors: Michel Guillaume , Chini Gregory P. 
Published: November 2018

The interaction of an acoustic wave with a stratified fluid can drive strong streaming flows owing to the baroclinic production of fluctuating vorticity, as recently demonstrated by Chini et al. (J. Fluid Mech., 744, 2014, pp. 329–351). In the present investigation, a set of wave/mean-flow interaction equations is derived that governs the coupled dynamics of a standing acoustic-wave mode of characteristic (small) amplitude $\unicode[STIX]{x1D716}$ and the streaming flow it drives in a thin channel with walls maintained at differing temperatures. Unlike classical Rayleigh streaming, the resulting mean flow arises at $O(\unicode[STIX]{x1D716})$ rather than at $O(\unicode[STIX]{x1D716}^{2})$. Consequently, fully two-way coupling between the waves and the mean flow is possible: the streaming is sufficiently strong to induce $O(1)$ rearrangements of the imposed background temperature and density fields, which modifies the spatial structure and frequency of the acoustic mode on the streaming time scale. A novel Wentzel–Kramers–Brillouin–Jeffreys analysis is developed to average over the fast wave dynamics, enabling the coupled system to be integrated strictly on the slow time scale of the streaming flow. Analytical solutions of the reduced system are derived for weak wave forcing and are shown to reproduce results from prior direct numerical simulations (DNS) of the compressible Navier–Stokes and heat equations with remarkable accuracy. Moreover, numerical simulations of the reduced system are performed in the regime of strong wave/mean-flow coupling for a fraction of the computational cost of the corresponding DNS. These simulations shed light on the potential for baroclinic acoustic streaming to be used as an effective means to enhance heat transfer.
Team Leaders Matter in Knowledge Sharing: A Cross-Level Analysis of the Interplay between Leaders’ and Members’ Goal Orientations in the Chinese Context
Authors: Zhang Jiamin , Wang Yi , Zhang Marina Yue 
Published: November 2018

ABSTRACTThis article investigates the impact of cross-level interplay between team members’ and their leaders’ goal orientations (learning, performance approach, and performance avoidance) on knowledge sharing using samples from design teams in two companies in China. Our results show that team leaders’ learning goal orientation plays a critical moderating role. Specifically, team leaders’ learning goal orientation strengthens the positive relationship between team members’ learning orientation and knowledge sharing; positively moderates the relationship between team members’ performance approach orientation and knowledge sharing; and weakens the negative relationship between team members’ performance avoidance orientation and knowledge sharing. Team leaders’ performance approach orientation demonstrates a positive moderating effect when there is congruence between the performance approach orientation of leaders and members. Finally, team leaders’ performance avoidance orientation negatively moderates the relationship between team members’ learning and performance approach orientation on knowledge sharing. This research enhances our understanding of the conditions under which knowledge sharing occurs among team members, using the lens of Trait Activation Theory.
Hyper-longirostry and kinematic disparity in extinct toothed whales
Authors: McCurry Matthew R. , Pyenson Nicholas D. 
Published: November 2018

AbstractToothed cetacean (Odontoceti) lineages in the Miocene and Pliocene evolved rostra that are proportionally more elongate than any other aquatic mammal or reptile, living or extinct. Their similarities in cranial proportions to billfish may suggest a convergent feeding style, where the rostrum is swept through the water to hit and stun prey. Here we calculated second moment of area from rostral cross sections of these fossil odontocete taxa, as well as from extant ecological analogues, to infer variation in feeding behavior. Our results show that the extremely long rostra of extinct toothed whales vary considerably in functionally relevant measures of shape and likely exhibited a diversity of feeding behaviors, ranging from those similar to modern odontocetes to those convergent with billfish. Eustatic sea-level and temperature maxima of the Miocene likely led to changes in prey characteristics or abundance that enabled the repeated evolution of this extreme morphotype, which later went extinct during late Pliocene climatic deterioration.
How conceptualizing influences fluency in first and second language speech production
Authors: FELKER EMILY R. , KLOCKMANN HEIDI E. , DE JONG NIVJA H. 
Published: November 2018

ABSTRACTWhen speaking in any language, speakers must conceptualize what they want to say before they can formulate and articulate their message. We present two experiments employing a novel experimental paradigm in which the formulating and articulating stages of speech production were kept identical across conditions of differing conceptualizing difficulty. We tracked the effect of difficulty in conceptualizing during the generation of speech (Experiment 1) and during the abandonment and regeneration of speech (Experiment 2) on speaking fluency by Dutch native speakers in their first (L1) and second (L2) language (English). The results showed that abandoning and especially regenerating a speech plan taxes the speaker, leading to disfluencies. For most fluency measures, the increases in disfluency were similar across L1 and L2. However, a significant interaction revealed that abandoning and regenerating a speech plan increases the time needed to solve conceptual difficulties while speaking in the L2 to a greater degree than in the L1. This finding supports theories in which cognitive resources for conceptualizing are shared with those used for later stages of speech planning. Furthermore, a practical implication for language assessment is that increasing the conceptual difficulty of speaking tasks should be considered with caution.