bluuebunny/crossref_metadata_2025 huggingface dataset:
The Relative Importance of Saturated Silica Sand Interfacial and Pore Fluid Geochemistry on the Spectral Induced Polarization Response
Authors: Peruzzo Luca , Schmutz Myriam , Franceschi Michel , Wu Yuxin , Hubbard Susan S.
Published: May 2018

Adsorption at the solid‐pore fluid interface is a key mechanism controlling the mobility of nutrients and contaminants in subsurface soils and sediments. The spectral induced polarization (SIP) method has been shown to be sensitive to the quantity and type of adsorbed ions. Extending previous results, we investigated the relevance of pH, solution conductivity, and ion type on the SIP response of saturated silica sand. We also performed adsorption experiments to evaluate whether adsorption plays a relevant role on the effect of saturating solution conductivity and pH. Given their environmental relevance and different electrochemical characteristics, we focused on exploring the influence of Cu2+ and Na+ adsorption on the SIP signature. The adsorption results confirm the expected and modeled pH influence on the adsorption of both Cu2+ and Na+. The measured quadrature conductivity spectra indicate that pH and solution conductivity control the electrical double layer electrochemical state and its capacitive behavior. On the contrary, no appreciable SIP signal changes are associated with ion substitution. The adsorption experiments highlight low values of site occupancy for Na and Cu, which suggests that the effects of pH and fluid conductivity are unrelated to their control on the ion adsorption. We interpret the solution conductivity as a proxy for ionic strength. The relative importance of pH and solution conductivity over ion type helps to further constrain the interpretation of SIP results in field geochemical and biogeochemical characterization and monitoring.
Late Miocene Extensional Collapse of Northern Tunisia
Authors: Booth‐Rea G. , Gaidi S. , Melki F. , Marzougui W. , Azañón J. M. , Zargouni F. , Galvé J. P. , Pérez‐Peña J. V.
Published: May 2018

Two orthogonal extensional systems produced the extensional collapse of the Tell and Atlas thrust belts in northern Tunisia during the Late Miocene to Pliocene in a context of NW‐SE plate convergence between Africa and Eurasia. The older extensional system shows several low‐angle normal faults (LANFs) and associated high‐angle faults with ENE‐directed transport that produced half‐grabens and hanging‐wall syncline basins during the late Tortonian to Messinian. The direction of extension swinged towards the SE during the Messinian, cutting into, and tilting the previous detachments. Extension was accompanied by the extrusion of 8‐Ma rhyodacites and Messinian basalts, together with the development of mineralized fault breccias. Plio‐Quaternary NW‐SE directed shortening formed inversion arrowhead structures, reverse faults, refolded extensional rollover anticlines and folded the LANFs. ENE‐directed extension is concomitant with the opening of the Tyrrhenian basin. We consequently think that both processes are related and that tearing of the Calabrian slab along the northern Tunisia coast drove the ENE‐directed extension. Meanwhile, the SE‐directed extension that followed was probably related to SE‐directed peeling back of the Tunisian continental lithospheric mantle during NW subduction of the Maghrebian margin. This extension propagated eastwards from the late Tortonian until the Pliocene following the SE migrating subduction front and favored by lateral slab tearing along the Tunisian Atlas dextral Subduction Transfer Edge Propagator boundary. This new hypothesis for the tectonic evolution of northern Tunisia shows for the first time the importance of crustal extension in the denudation of the Tunisian Atlas and Tell foreland thrust belts and its relation to deep mantle tectonic mechanisms.
Methane, Climate Change, and Our Uncertain Future
Authors: Dean Joshua
Published: May 2018

Methane is generally considered secondary to carbon dioxide in its importance to climate change, but what role might methane play in the future if global temperatures continue to rise?
Tasty Treats from the 2018 Great Geobakeoff
Authors: Cartier Kimberly , Kumar Mohi
Published: May 2018

Eat your way across fascinating geologic marvels, one sweet, sugary dessert at a time.
3‐D Seismic Investigation of a Gas Hydrate and Fluid Flow System on an Active Mid‐Ocean Ridge; Svyatogor Ridge, Fram Strait
Authors: Waghorn Kate A. , Bünz Stefan , Plaza‐Faverola Andreia , Johnson Joel E.
Published: May 2018

Tectonic settings play a large role in the development of fluid flow pathways for gas migrating through sedimentary strata. Gas hydrate systems worldwide are located on either the slopes of passive continental margins, often in large contourite deposits, or in accretionary wedges on subduction margins. The Svyatogor Ridge, however, located at the northwestern flank of the Knipovich Ridge and south of the Molloy Transform Fault (Fram Strait), is a gas hydrate system which is located on an actively spreading margin. Svyatogor Ridge has evidence of shallow gas accumulations; a strong BSR indicating a gas hydrate and underlying free gas system, and fluid flow pathways to the seafloor culminating in pockmarks. Using a high‐resolution P‐Cable 3‐D seismic survey, we investigate how tectonic and sedimentary regimes have influenced the formation of this well‐developed gas hydrate system. Large‐scale basement faults identified in the seismic data are interpreted as detachment faults, which have exhumed relatively young ultramafic rocks. These detachment faults act as conduits for fluid flow, and are responsible for the formation of folds in the overlying sediments that are breached by faults. We propose a model for fluid flow within this system whereby as sedimentary faults breach upward through the sedimentary strata, fluid is able to migrate further upward. We find that the tectonic regime on Svyatogor Ridge is the dominant driver of fluid migration and episodic release at the seafloor.
Seismic Imaging of Thickened Lithosphere Resulting From Plume Pulsing Beneath Iceland
Authors: Rychert Catherine A. , Harmon Nicholas , Armitage John J.
Published: May 2018

Ocean plates conductively cool and subside with seafloor age. Plate thickening with age is also predicted, and hot spots may cause thinning. However, both are debated and depend on the way the plate is defined. Determining the thickness of the plates along with the process that governs it has proven challenging. We use S‐to‐P (Sp) receiver functions to image a strong, persistent LAB beneath Iceland where the mid‐Atlantic Ridge interacts with a plume with hypothesized pulsating thermal anomaly. The plate is thickest, up to 84 ± 6 km, beneath lithosphere formed during times of hypothesized hotter plume temperatures and as thin as 61 ± 6 km beneath regions formed during colder intervals. We performed geodynamic modeling to show that these plate thicknesses are inconsistent with a thermal lithosphere. Instead, periods of increased plume temperatures likely increased the melting depth, causing deeper depletion and dehydration, and creating a thicker plate. This suggests plate thickness is dictated by the conditions of plate formation.
SHTools: Tools for Working with Spherical Harmonics
Authors: Wieczorek Mark A. , Meschede Matthias
Published: May 2018

Geophysical analyses are often performed in spherical geometry and require the use of spherical harmonic functions to express observables or physical quantities. When expanded to high degree, the accuracy and speed of the spherical harmonic transforms and reconstructions are of paramount importance. SHTools is a time and user‐tested open‐source archive of both Fortran 95 and Python routines for performing spherical harmonic analyses. The routines support all spherical‐harmonic normalization conventions used in the geosciences, including 4π‐normalized, Schmidt seminormalized, orthonormalized, and unnormalized harmonics, along with the option of employing the Condon‐Shortley phase factor of
. Data on the sphere can be sampled on a variety of grid formats, including equally spaced cylindrical grids and grids appropriate for integration by Gauss‐Legendre quadrature. The spherical‐harmonic transforms are proven to be fast and accurate for spherical harmonic degrees up to 2800. Several tools are provided for the geoscientist, including routines for performing localized spectral analyses and basic operations related to global gravity and magnetic fields. In the Python environment, operations are very simple to perform as a result of three class structures that encompass all operations on grids, spherical harmonic coefficients, and spatiospectral localization windows. SHTools is released under the unrestrictive BSD 3‐clause license.
Presence and Consequences of Coexisting Methane Gas With Hydrate Under Two Phase Water‐Hydrate Stability Conditions
Authors: Sahoo Sourav K. , Marín‐Moreno Héctor , North Laurence J. , Falcon‐Suarez Ismael , Madhusudhan Bangalore N. , Best Angus I. , Minshull Tim A.
Published: May 2018

Methane hydrate saturation estimates from remote geophysical data and borehole logs are needed to assess the role of hydrates in climate change, continental slope stability, and energy resource potential. Here we present laboratory hydrate formation/dissociation experiments in which we determined the methane hydrate content independently from pore pressure and temperature and from electrical resistivity. Using these laboratory experiments, we demonstrate that hydrate formation does not take up all the methane gas or water even if the system is under two phase water‐hydrate stability conditions and gas is well distributed in the sample. The experiment started with methane gas and water saturations of 16.5% and 83.5%, respectively; during the experiment, hydrate saturation proceeded up to 26% along with 12% gas and 62% water remaining in the system. The coexistence of hydrate and gas is one possible explanation for discrepancies between estimates of hydrate saturation from electrical and acoustic methods. We suggest that an important mechanism for this coexistence is the formation of a hydrate film enveloping methane gas bubbles, trapping the remaining gas inside.
Crustal Structure of Southwest China and Northern Vietnam From Ambient Noise Tomography: Implication for the Large‐Scale Material Transport Model in SE Tibet
Authors: Qiao Lei , Yao Huajian , Lai Ya‐Chuan , Huang Bor‐Shouh , Zhang Ping
Published: May 2018

Several models have been proposed to describe the tectonic evolution of SE Tibet and its marginal areas. Hence, high‐resolution crustal velocity models are essential to address this controversy. With waveform data from 73 broadband stations in southwest China and northern Vietnam, we invert for a 3‐D shear wave velocity model of the crust and uppermost mantle from ambient noise tomography. Our model reveals that the midlower crustal low‐velocity zone in the Xiaojiang Fault Zone extends farther southward across the Red River Fault to Vietnam and is approximately bounded by the Xiaojiang and Dien Bien Phu faults to the east. We suggest that the observed low‐velocity zone represents a mechanically weak zone in the mid‐lower crust, which may serve as a channel for efficient southward material transport in SE Tibet. With our results and previous evidence, we propose a combined model that integrates rigid block extrusion and crustal channel flow to describe the large‐scale material transport in SE Tibet. We further propose a two‐phase material transport model in SE Tibet after the India‐Eurasia plate collision: (1) rigid block extrusion between the right‐lateral Sagaing Fault and left‐lateral Red River Fault during the early Oligocene‐early Miocene and (2) a combined model of rigid block extrusion and material channel flow in the mid‐lower crust from the late Miocene to the present. The southward crustal material transport is likely to be diverted along two major channels around the more rigid crust beneath the inner zone of the Emeishan large igneous province.
A new photoelectrochemical biosensor for ultrasensitive determination of nucleic acids based on a three-stage cascade signal amplification strategy
Authors: Xiong Erhu , Yan Xiaoxia , Zhang Xiaohua , Li Yanmei , Yang Ruiying , Meng Leixia , Chen Jinhua
Published: May 2018

Based on a “signal-on” sensing strategy and a three-stage cascade signal amplification method, an ultrasensitive photoelectrochemical biosensor has been developed for DNA detection.
One-pot hydrothermal synthesis of amine-functionalized metal–organic framework/ reduced graphene oxide composites for the electrochemical detection of bisphenol A
Authors: Ling Li Jing , Xu Jing Ping , Deng Yan Hua , Peng Qian , Chen Jian Hua , San He Ya , Nie Yu Jing
Published: May 2018

Schematic of the preparation process of NH2-MIL-125/RGO/GCE.
Pd-Catalyzed reductive heck reaction of olefins with aryl bromides for Csp2–Csp3 bond formation
Authors: Jin Liqun , Qian Jiaxia , Sun Nan , Hu Baoxiang , Shen Zhenlu , Hu Xinquan
Published: May 2018

We developed a Pd-catalyzed intermolecular reductive Heck reaction to construct Csp2–Csp3 bonds between aryl bromides and olefins.
Iron nanoparticles in capsules: derived from mesoporous silica-protected Prussian blue microcubes for efficient selenium removal
Authors: Wang Qingqing , Zhao Yuye , Luo Wei , Jiang Weizhong , Fan Jianwei , Wang Lianjun , Jiang Wan , Zhang Wei-xian , Yang Jianping
Published: May 2018

A “simultaneous removal–recovery” strategy for pollutants is realized by using Fe/C@mSiO2capsules.
Fabrication of hollow nanorod electrodes based on RuO2//Fe2O3 for an asymmetric supercapacitor
Authors: Wang Qiufan , Liang Xiao , Ma Yun , Zhang Daohong
Published: May 2018

A novel type of asymmetric supercapacitor was fabricated by assembling a RuO2 positive electrode and a Fe2O3 negative electrode. Full cells are constructed and show a high capacitance of 4.9 F cm−3, a high energy density of 1.5 mW h cm−3 and a high power density of 9.1 mW cm−3.
A modular strategy for decorating isolated cobalt atoms into multichannel carbon matrix for electrocatalytic oxygen reduction
Authors: Zhang Huabin , Zhou Wei , Chen Tao , Guan Bu Yuan , Li Zhen , Lou Xiong Wen (David)
Published: May 2018

Isolated cobalt atoms with CoN4configuration are decorated into a multichannel carbon matrix for efficient electrocatalytic oxygen reduction reaction.
A zeolitic imidazolate framework-8-based indocyanine green theranostic agent for infrared fluorescence imaging and photothermal therapy
Authors: Wang Tianzheng , Li Siqi , Zou Zhen , Hai Luo , Yang Xue , Jia Xin , Zhang Anman , He Dinggeng , He Xiaoxiao , Wang Kemin
Published: May 2018

A zeolitic imidazolate framework-8-based indocyanine green theranostic agent was constructed for fluorescence imaging and photothermal therapy of tumors in vivo.
Hydrophobicity-guided self-assembled particles of silver nanoclusters with aggregation-induced emission and their use in sensing and bioimaging
Authors: Pan Saifei , Liu Weidong , Tang Jiantao , Yang Yingjie , Feng Hui , Qian Zhaosheng , Zhou Jin
Published: May 2018

Hydrophobicity-guided self-assembled particles of silver nanoclusters with aggregation-induced emission were fabricated and used in sensing and bioimaging.
Tris(ethylene diamine) nickel acetate as a promising precursor for hole transport layer in planar structured perovskite solar cells
Authors: Saranin Danila S. , Mazov Vsevolod N. , Luchnikov Lev O. , Lypenko Dmitry A. , Gostishev Pavel A. , Muratov Dmitry S. , Podgorny Dmitry A. , Migunov Denis M. , Didenko Sergei I. , Orlova Marina N. , Kuznetsov Denis V. , Tameev Alexey R. , Di Carlo Aldo
Published: May 2018

NiO/perovskite interface with novel NiO precursor was investigated with Auger profiling for solar cell with PCE > 15%.
Controllable optical tuning and improvement in Li+,Eu3+-codoped BaSc2O4:Bi3+based on energy transfer and charge compensation
Authors: Dang Peipei , Liang Sisi , Li Guogang , Wei Yi , Cheng Ziyong , Lian Hongzhou , Shang Mengmeng , Ho Seong Jang , Lin Jun
Published: May 2018

Improved photoluminescence and efficient blue-to-red color-tuning of novel BaSc2O4:Bi3+phosphors were achieved by Li+/BaF2lattice modification and Bi3+→ Eu3+energy transfer.
Effect of quantum tunneling on the efficiency of excitation energy transfer in plasmonic nanoparticle chain waveguides
Authors: Ilawe Niranjan V. , Oviedo M. Belén , Wong Bryan M.
Published: May 2018

Quantum-mechanical effects can result in qualitatively different (and sometimes completely opposite) results for excitation energy transfer in plasmonic waveguides.
Solvent-vapor-annealed A–D–A-type semicrystalline conjugated small molecules for flexible ambipolar field-effect transistors
Authors: Kim Min Je , Lee Young Woong , Lee Yujeong , Woo Han Young , Ho Cho Jeong
Published: May 2018

This paper reports a series of acceptor–donor–acceptor-type small molecules based on an oligothiophene–phenylene core with three different electron-accepting terminal groups—dicyanovinyl, cyano-rhodanine, and cyano-indanone, respectively—for application to flexible ambipolar organic field-effect transistors.
Boosting the electroluminescence efficiency of solution-processed thermally activated delayed fluorescence OLEDs with a versatile hole-transporting layer of organic–inorganic hybrid perovskite
Authors: Zhou Tao , Liu Cheng , Gong Shaolong , Xiang Yepeng , Xie Guohua , Yang Chuluo
Published: May 2018

An organic–inorganic hybrid perovskite, CzEAP, is explored as an effective hole-transporting layer for high-efficiency solution-processed TADF OLEDs.
Sub‐population prediction using enhanced correlation filters
Authors: Wang Hongfei , He Kun
Published: May 2018

Minimum average correlation energy (MACE) filters are initially developed and widely used for image pattern recognition tasks. A novel method leveraging the enhanced MACE filters is proposed to tackle classification problems from a new perspective. By employing 1D Fourier transform, establishing new identification metric, and improving numerical stability, the proposed method constructs an enhanced correlation filter to select a sub‐population of the un‐labelled data, and subsequently outputs labels. Experiments show our method achieves 100% precision on multiple datasets considered, including two public benchmarks and one obtained from semiconductor industry addressing an emerging task.
Fusion of inertial and visual information for indoor localisation
Authors: Xu Yan , Yu Hang , Zhang Jiahe
Published: May 2018

Indoor localisation has attracted a lot of attention because of its importance for location‐based services. A fusion algorithm (named as YELM‐DS) based on extreme learning machine (ELM) and Dempster–Shafer (D–S) evidence theory is proposed. ELM learns the input data model composed of inertial and visual information and target output positions with high speed. During online phase, the final localisation result of a frame is decided by the trust degree obtained from D–S. Angle judgments are also introduced to decrease the big localisation errors of turning. Compared with the existing vision‐only methods, the proposed method can both run in real time and achieve good localisation accuracy even in challenging scenarios.
FBG laser sensor with PS
Authors: Kim D. , Kim H. , Song M.
Published: May 2018

Owing to unstable multi‐wavelength lasing, robust measurement is difficult with a fibre Bragg grating (FBG) laser sensor system that uses FBGs as laser cavity mirrors as well as sensors. A stabilising technique is essential for proper data acquisition. Here, it is demonstrated that polarisation scrambling (PS) stabilises the output of laser sensor system in combination with a spectrometer demodulation. The state of polarisation (SOP) of a fibre‐optic laser cavity is changed by a 1 MHz PS. A 5 kHz spectrometer traces the distribution of output laser wavelengths. The rapid changes in SOP make all the FBG wavelengths lase as long as necessary to determine the Bragg wavelength shifts in the sampling windows of a photo‐diode array. A laser sensor system with eight FBG sensors is used to demonstrate robust measurement and data collection under environmental perturbations.
Compact UWB bandpass filter with sharp roll‐off using APCL structure
Authors: Xia Xinlin , Cheng Xu , Chen Fengjun , Deng Xianjin
Published: May 2018

In this letter, a quintuple‐mode bandpass filter for a UWB system with improved performance is presented. The presented filter is implemented with asymmetric parallel‐coupled lines loaded open stub and short stub connected at the symmetrical plane of the filter to increase its frequency selectivity. Five resonant frequencies within the UWB band and two transmission zeros at the lower and upper passband/stopband edges are observed. A filter prototype is fabricated for verification and the experimental data are corresponding well with the simulated results. The proposed filter achieves a bandwidth that can exactly cover the whole UWB frequency band. Moreover, this filter has a compact size (0.645λg × 0.318λg) and low insertion loss.
Offset mesh in FPCB for better impedance control
Authors: Yu S. , Kam D.G.
Published: May 2018

Meshed ground planes have been used in a flexible printed circuit board (FPCB) to raise the characteristic impedance of a stripline to 50 Ω. However, the characteristic impedance varies considerably with its position on the meshes. An offset mesh structure is proposed to address this issue. Both simulation and measurement results verify its effectiveness.
EIMAC: a multi‐channel MAC protocol towards energy efficiency and low interference for WBANs
Authors: Li Nannan , Cai Xuelian , Yuan Xiaoming , Zhang Yao , Zhang Beibei , Li Changle
Published: May 2018

Wireless body area networks (WBANs) can be widely used in wireless medical, motion detection etc. However, the existence of interference results in the increase in energy consumption and delay. To mitigate interference, nodes are prevented from using the same or similar spectrum resources by adopting multi‐channel media access control (MAC) protocols. Here, the authors propose a multi‐channel MAC protocol towards energy efficiency and low interference (EIMAC). Firstly, the states of each channel are clarified by the channel mapping mechanism. A novel channel selection strategy, considering the unfairness between high or low priorities, then is carried out. After that, considering the characteristics of node including residual energy, user priority, and data volume, the authors propose a low energy consumption enabled transmission mechanism. Lastly, the authors utilise a novel collision avoidance mechanism to reduce the collision probability of packets. Numerical results show that EIMAC significantly enhance the performance of WBANs in terms of delay, throughput, and energy consumption.
Numerical investigation of the effects of magnetic field and fluid electrical conductivity on the performance of marine magnetohydrodynamic motors
Authors: Haghparast Mortaza , Reza Alizadeh Pahlavani Mohammad , Azizi Diako
Published: May 2018

A magnetohydrodynamic (MHD) thruster is a type of electric motors which does not have mechanical moving parts and directly converts electrical energy into mechanical energy. In this study, the effect of magnetic field intensity and seawater electrical conductivity on the performance of a marine MHD thruster model is investigated using fully three‐dimensional numerical simulations. For the first time, all electric, magnetic and fluid flow fields are considered in three dimensions. The effects of seawater electrolysis and end loss are taken into account in all simulations and a simple analytical model is developed to verify the numerical results. It is shown that increasing the magnetic field intensity or the electrical conductivity of the working fluid decreases the electrochemical and ohmic losses of the thruster at a specific velocity. Therefore, a higher efficiency can be achieved at higher magnetic field strengths and higher seawater electrical conductivities. Also, it is revealed the end loss of the channel increases with an increase in the electrical conductivity of the working fluid and decreases with an increase in the magnetic field intensity.
Parameters and performance analysis of a dual stator composite rotor axial flux induction motor by an analytical method
Authors: Hong Cencen , Huang Wenxin , Hu Zhenwei
Published: May 2018

This study proposes a novel dual stator composite rotor axial flux induction motor (DSCRAFIM) whose solid rotor is coated with copper layers. A novel multi‐slice and multi‐layer method is developed and applied to analyse the three‐dimensional electromagnetic field distribution in DSCRAFIM. In the application of this analytical method, DSCRAFIM is equivalent to a finite set of equal‐width and increasing‐length double primary composite secondary linear induction motors, whose steel secondary is divided into a finite set of equal‐height layers. The surface impedance theory is applied to derive the improved equivalent circuit model (IECM) of DSCRAFIM, which considers the coupling relationship between dual stator windings. The accuracy of this IECM is then verified by both finite‐element analysis and experimental test.
Rotor position estimation scheme with harmonic ripple attenuation for sensorless controlled permanent magnet synchronous motors
Authors: Lu Qing , Zhu Xiaoyong , Quan Li , Zuo Yuefei , Du Sichen
Published: May 2018

To achieve high‐performance sensorless control of permanent magnet motors with non‐sinusoidal back electromotive force (EMF), an improved sliding mode observer (SMO) adopting synchronous rotating low‐pass filter (SRLPF) is proposed. The SRLPF is utilised to reduce the back‐EMF harmonics and extract the fundamental component. Different from the traditional rotor position observer, the proposed observer can calculate the rotor position with the back‐EMF fundamental component. Owing to the decrease in the influence of non‐sinusoidal back‐EMF, the estimated rotor position harmonic ripple error can be greatly reduced. Then, the high estimated accuracy and excellent sensorless control performance can be obtained. In addition, the proposed strategy is easy for implementation. With the comparison between the traditional SMO and the proposed observer, the experiments of the system steady‐state error, the speed tracking performance, and the disturbance rejection ability in the speed range from 60 r/min to the rated speed 750 r/min are presented. The validity of the proposed method is conformed.
Calculation of rotor losses in PM machines with retaining sleeves using transfer matrices
Authors: Renedo Anglada Jaime , Sharkh Suleiman M. , Yuratich Michael A.
Published: May 2018

Accurate calculation of rotor losses in permanent magnet (PM) synchronous machines can be critical because these losses tend to be very small relative to others in the machine. Numerical methods, such as finite element analysis (FEA), can now provide accurate estimates of these losses, but they, especially 3D‐FEA, can be time consuming. Analytical methods therefore remain very useful as quick tools for estimating losses at the early design stages. This study presents a new improved analytical method for the calculations of rotor eddy current losses in PM machines using a reformulation of the current sheet model into transfer matrices to solve Helmholtz's diffusion equation. Such methodology reduces the complexity of the problem significantly, particularly in machines with retaining sleeves, and simplifies the numerical evaluation of the resulting equations. A high‐speed PM machine with a retaining sleeve is presented as a case study. The analytical results are verified using FEA.
Design methodology for high‐speed synchronous reluctance machines
Authors: Babetto Cristian , Bacco Giacomo , Bianchi Nicola
Published: May 2018

This study presents two design methodologies for high‐speed synchronous reluctance (REL) machines. The interest for high‐speed drives comes from the request for compactness and high efficiency. The synchronous REL motors have been widely studied for several applications, but a coherent design procedure for high speed has not been proposed in the literature. The study proposes some analytical procedures to get an initial design. Then the rotor geometry optimisation through a differential evolution algorithm is described. Finally, a design example is given and thoroughly analysed using these two approaches.
Sliding‐mode observer‐based speed‐sensorless vector control of linear induction motor with a parallel secondary resistance online identification
Authors: Wang Huimin , Liu Yong‐chao , Ge Xinglai
Published: May 2018

This study proposes a speed estimation scheme for the sensorless‐vector‐controlled linear induction motor (LIM) drives for medium–low‐speed maglev applications, which is composed of two parts: (i) a sliding mode model reference adaptive system observer for speed estimation; and (ii) a parallel secondary resistance online identification for achieving the improvements of the proposed speed estimation scheme performance. The sliding mode observer (SMO) is established on the basis of the state space‐vector model of the LIM considering the dynamic end effect. Based on SMO, both speed and secondary resistance estimation algorithms are obtained by utilising Popov's hyperstability theory. Moreover, the Lyapunov stability theory is adopted for the stability analysis of the proposed speed estimation scheme. The effectiveness of the proposed speed estimation algorithm has been verified and compared with the performance of the conventional speed estimation scheme based on single‐manifold SMO by the simulation and hardware‐in‐the‐loop tests.
Influence of sleeve thickness and various structures on eddy current losses of rotor parts and temperature field in surface mounted permanent‐magnet synchronous motor
Authors: Li Lin , Li Weili , Li Dong , Zhang Xiaochen , Fan Yu
Published: May 2018

For surface mounted permanent magnet synchronous motor (PMSM), due to the large rotor rotational centrifugal forces, a sleeve is often used to prevent damage to rotor permanent magnets. However, eddy current losses appearing in the sleeve can increase the temperature of surface mounted PMSM. If the rotor heat dissipation condition is poor, high temperature can influence the surface mounted PMSM performance and even result in thermal demagnetisation of the permanent magnets. Thus, a sleeve scheme designed with low eddy current loss is very necessary. In this study, taking a 12.5 kW, 2000 rpm PMSM with 0.2 mm thickness stainless steel sleeve as an example, first, the influences of sleeve thickness on the eddy current loss and temperature field are analysed. Then, sleeve various composition structures of carbon fibre and stainless steel are presented, and the influences of different composition percentages on the eddy current losses and temperature field are analysed in detail, which shows the effectiveness in reducing the eddy current losses and temperature in the rotor. The obtained conclusions can provide useful reference for the design and research of surface mounted PMSM.
Calculation of unbalanced magnetic pull in induction machines through empirical method
Authors: Chuan Hawwooi , Shek Jonathan K.H.
Published: May 2018

Unbalanced magnetic pull (UMP) occurred due to the uneven distribution of magnetic flux around the airgap, which can be caused by the existence of rotor eccentricity in the machines. Here, a UMP damping coefficient is introduced to explain the UMP damping effect from the counteracting flux produced by a parallel‐connected cage rotor. An empirical method is proposed to calculate the UMP using the damping coefficient and an analytical model. Using the proposed method, a four‐pole and eight‐pole squirrel cage induction machine with static eccentricity are investigated, which uses inputs from both finite element analysis and experimental work. Then, the UMP calculation for a dynamic eccentricity with the extracted parameters is done to verify the empirical method. A slip control method is described which uses a UMP/torque ratio to find the operating slip with the lowest UMP. Comparisons between results with and without slip control are made on both induction machines. It shows that great reduction in UMP can be achieved when the machine is lightly loaded.
Model predictive control approach for frequency and voltage control of standalone micro‐grid
Authors: Puvvula Sri Rama Venkata Ranga Sai Sesha Vidyasagar , Kesanakurthy Shanti Swarup
Published: May 2018

The frequency and voltage control of a standalone micro‐grid with synchronous generator‐based distributed generator and electronically interfaced generator is discussed. A centralised linear model predictive controller is employed. The controller design is based on the state space model of the micro‐grid. To decrease the number of optimising variables and calculation time of optimal control trajectory, the design of the controller is realised with the help of orthonormal Laguerre polynomials. The numerical instabilities that arise during implementation and the possible ways to overcome them are discussed. The impact of different generator constraints on the controller operation is discussed. Formulation of the micro‐grid model and identifying the appropriate inputs and outputs to the controller is discussed in detail with the help of an eight bus micro‐grid.
Synchro‐phasors Assisted Back‐up Protection of Transmission Line
Authors: Nougain Vibhuti , Jena Manas K. , Panigrahi Bijaya K.
Published: May 2018

Certain power system situations force protection schemes to mal‐operate. Such mal‐operations associated with back‐up protection (BP) schemes might worsen the situation by initiating the cascading effect, damaging critical elements such as generation units, transformers etc. of the power system, or leading to complete collapse of the power system. To adapt to such a network structure, the relays which are going to participate in BP of transmission line have to evolve. Integration of protection systems, communication network, and computer technology has to be the approach for faster information sharing and decision making. Analysis of recent blackouts clearly shows the importance of advancement of wide‐area measurement systems and adaptive nature of relaying. Synchro‐phasors assisted BP scheme is proposed in this work, which helps the relays adapt according to the prevailing system situations and decisive action is taken considering security and dependability aspects of the relays.
Aerodrome situational awareness of unmanned aircraft: an integrated self‐learning approach with Bayesian network semantic segmentation
Authors: Lu Bowen , Coombes Matthew , Li Baibing , Chen Wen‐Hua
Published: May 2018

It is expected that soon there will be a significant number of unmanned aerial vehicles (UAVs) operating side‐by‐side with manned civil aircraft in national airspace systems. To be able to integrate UAVs safely with civil traffic, a number of challenges must be overcome first. This study investigates situational awareness of UAVs’ autonomous taxiing in an aerodrome environment. The research work is based on a real outdoor experimental data collected at the Walney Island Airport, the UK. It aims to further develop and test UAVs’ autonomous taxiing in a challenging outdoor environment. To address various practical issues arising from the outdoor aerodrome such as camera vibration, taxiway feature extraction, and unknown obstacles, the authors develop an integrated approach that combines the Bayesian‐network based semantic segmentation with a self‐learning method to enhance situational awareness of UAVs. Detailed analysis of the outdoor experimental data shows that the integrated method developed in this study improves the robustness of situational awareness for autonomous taxiing.
Estimating urban traffic states using iterative refinement and Wardrop equilibria
Authors: Li Weizi , Jiang Meilei , Chen Yaoyu , Lin Ming C.
Published: May 2018

Traffic has become a major problem in metropolitan areas across the world. It is critical to understand the complex interplay of a road network and its traffic states so that researchers and planners can improve the city planning and traffic logistics. The authors propose a novel framework to estimate urban traffic states using GPS traces. Their approach begins with an initial estimation of network travel times by solving a convex optimisation programme based on Wardrop equilibria. Then, they iteratively refine the estimated network travel times and vehicle traversed paths. Lastly, using the refined results as input, they perform a nested optimisation process to derive traffic states in areas without data coverage to obtain full traffic estimations. The evaluation and comparison of their approach over two state‐of‐the‐art methods show up to 96% relative improvements. In order to study urban traffic, the authors have further conducted field tests in Beijing and San Francisco using real‐world GIS data, which involve 128,701 nodes, 148,899 road segments, and over 26 million GPS traces.
Computational study on focused microwave thermotherapy for knee pathological treatment
Authors: Kim Jang‐Yeol , Jeon Soon‐Ik , Lee Kwang‐Jae , Kim Bo‐Ra , Simonov Nikolai , Yoon Joon Shik , Kim Nam , Son Seong‐Ho
Published: May 2018

This study is a computational study on focused microwave thermotherapy for knee pathological treatment using the time reversal (TR) principle in musculoskeletal disorders. The authors presented a modified TR algorithm with amplitude compensation for an accurate beam focusing of the knee tumour location in a lossy medium. Furthermore, they proposed a new approach called the truncated threshold method, which could be used to apply an effective beam focusing on a tumour location in the knee while the unwanted hot spots are controlled in the normal tissue region. Compared to the other existing methods, this new approach has the advantages of being implemented simply in the unwanted hot spot control and having a similar performance to the beam focusing on the target location. The application of the proposed algorithm and the new hot spot control method to knee pathological tissue achieved acceptable electromagnetic (EM) and thermal results. The anatomical based two‐dimensional (2D) knee model for the simulation analysis was implemented using a segmentation result of the Korean human body model obtained from magnetic resonance imaging. 2D finite‐difference time‐domain electromagnetic and thermal solvers were developed and applied to conduct the 915 MHz focused microwave thermotherapy for knee pathological treatment.
Star clusters in the Magellanic Clouds
Authors: Nayak P. K. , Subramaniam A. , Choudhury S. , Sagar Ram
Published: May 2018

Aims. We aim to estimate the age and reddening parameters of already identified star clusters within the Small Magellanic Cloud (SMC) in a consistent way using available photometric data, classify them based on their mass and strength, and study their spatiotemporal distribution.

Methods. We have used a semi-automated quantitative method, developed in the first paper of this series (Paper I), to estimate the cluster parameters using the V and I band photometric data from the Optical Gravitational Lensing Experiment (OGLE) III survey.

Results. We estimated parameters of 179 star clusters (17 are newly parameterised) and classified them into four groups. We present an online catalogue of parameters as well as cleaned and isochrone-fitted colour magnitude diagrams of 179 clusters.

We compiled age information of 468 clusters by combining previous studies with our catalogue, to study their spatio-temporal distribution. Most of the clusters located in the southern part of the SMC are in the age range 600 Myr–1.25 Gyr, whereas, the clusters younger than 100 Myr are mostly found in the northern SMC, with the central SMC showing continuous cluster formation. The peak of the cluster age distribution is identified at 130 ± 35 Myr, very similar to the Large Magellanic Cloud (LMC) in Paper I.

Conclusions. We suggest that the burst of cluster formation at 130 Myr is due to the most recent LMC-SMC interaction. 90% of the studied sample is found to have mass < 1700 M⊙, suggesting that the SMC is dominated by low mass clusters. There is tentative evidence for compact clusters in the LMC when compared to those in the Galaxy and the SMC. A progressive shifting of cluster location from the south to north of the SMC is identified in last ~600 Myr. The details of spatio-temporal distribution of clusters presented in two videos as part of this study can be used as a tool to constrain details of the recent LMC-SMC interactions.
Forward seismic modeling of the pulsating magnetic B-type star HD 43317
Authors: Buysschaert B. , Aerts C. , Bowman D. M. , Johnston C. , Van Reeth T. , Pedersen M. G. , Mathis S. , Neiner C.
Published: May 2018

The large-scale magnetic fields detected at the surface of about 10% of hot stars extend into the stellar interior, where they may alter the structure. Deep inner regions of stars are only observable using asteroseismology. Here, we investigate the pulsating magnetic B3.5V starHD 43317, infer its interior properties and assess whether the dipolar magnetic field with a surface strength ofBp= 1312 ± 332 G causes different properties compared to those of non-magnetic stars. We analyze the latest version of the star’s 150 d CoRoT light curve and extract 35 significant frequencies, 28 of which are found to be independent and not related to the known surface rotation period ofProt= 0.897673 d. We perform forward seismic modeling based on non-magnetic, non-rotating 1D MESA models and the adiabatic module of the pulsation code GYRE, using a grid-based approach. Our aim was to estimate the stellar mass, age, and convective core overshooting. The GYRE calculations were done for uniform rotation withProt. This modeling is able to explain 16 of the 28 frequencies as gravity modes belonging to retrograde modes with (ℓ, m) = (1, −1) and (2, −1) period spacing patterns and one distinct prograde (2, +2) mode. The modeling resulted in a stellar massM⋆ = 5.8−0.2+0.1M⊙, a central hydrogen mass fractionXc = 0.54−0.02+0.01, and exponential convective core overshooting parameterfov = 0.004−0.002+0.014. The low value forfovis compatible with the suppression of near-core mixing due to a magnetic field but the uncertainties are too large to pinpoint such suppression as the sole physical interpretation. We assess the frequency shifts of pulsation modes caused by the Lorentz and the Coriolis forces and find magnetism to have a lower impact than rotation for this star. Including magnetism in future pulsation computations would be highly relevant to exploit current and future photometric time series spanning at least one year, such as those assembled by theKeplerspace telescope and expected from the TESS (Continuous Viewing Zone) and PLATO space missions.
Diagnostic Video of Infantile Masturbation
Authors: Sertdemir Merve , Bilgiç Ayhan
Published: May 2018

In this case report, the presentation and diagnosis of infantile masturbation by home video footage in a 12-month-old girl are discussed.
Homeopathic Prevention and Management of Epidemic Diseases
Authors: Jacobs Jennifer
Published: May 2018

Background Homeopathy has been used to treat epidemic diseases since the time of Hahnemann, who used Belladonna to treat scarlet fever. Since then, several approaches using homeopathy for epidemic diseases have been proposed, including individualization, combination remedies, genus epidemicus, and isopathy.

Methods The homeopathic research literature was searched to find examples of each of these approaches and to evaluate which were effective.

Results There is good experimental evidence for each of these approaches. While individualization is the gold standard, it is impractical to use on a widespread basis. Combination remedies can be effective but must be based on the symptoms of a given epidemic in a specific location. Treatment with genus epidemicus can also be successful if based on data from many practitioners. Finally, isopathy shows promise and might be more readily accepted by mainstream medicine due to its similarity to vaccination.

Conclusion Several different homeopathic methods can be used to treat epidemic diseases. The challenge for the future is to refine these approaches and to build on the knowledge base with additional rigorous trials. If and when conventional medicine runs out of options for treating epidemic diseases, homeopathy could be seen as an attractive alternative, but only if there is viable experimental evidence of its success.
The Recipient Venule in Supermicrosurgical Lymphaticovenular Anastomosis: Flow Dynamic Classification and Correlation with Surgical Outcomes
Authors: Salgarello Marzia , Hayashi Akitatsu , Visconti Giuseppe
Published: May 2018

Background Venules have been usually neglected in the literature on lymphaticovenular anastomosis (LVA). The aim of this study was to analyze the flow dynamic of recipient venules in LVA and their impact on the surgical outcomes.

Patients and Methods Data from 128 patients affected by extremity lymphedema, who underwent LVA, were collected in two institutions from August 2014 to May 2016. Recipient venules were classified according to their flow dynamic into backflow, slack, and outlet (BSO classification). Quantitative (lower extremity lymphedema/upper extremity lymphedema index) and qualitative outcomes (needing of compression garment and compression garment class) were evaluated. Chi-square test or Fisher's exact test was used for categorical variables and independent-samples t-test for continuous variables. The association between lymphatic collector degeneration status (normal, ectasis, contractile, sclerotic type [NECST]) and BSO classification with the outcomes was analyzed by the Mantel–Haenszel test.

Results On a total of 128 patients, 37 suffered from upper and 91 from lower limb lymphedema. An average number of four LVA were performed for each patient (range: 2–8). A significant association was observed between NECST and BSO categories and the outcomes were evaluated. Patients with contractile and sclerotic collectors had 2.24 times the odd of having poor composite outcome compared with those with normal-to-ectasis collectors (p < 0.05). Patients with backflow venules had 3.32 times the odd of having poor composite outcome compared with those without outlet or slack pattern (p < 0.05).

Conclusion The subtype of recipient venule flow dynamic has a significant impact on the surgical outcome of patients undergoing LVA for the treatment of lymphedema, regardless of the lymphatic collector degeneration status. Locating favorable venules in the preoperative mapping might enhance the surgical outcomes.