bluuebunny/crossref_metadata_2025 huggingface dataset:
Polysyllable Speech Accuracy and Predictors of Later Literacy Development in Preschool Children With Speech Sound Disorders
Authors: Masso Sarah , Baker Elise , McLeod Sharynne , Wang Cen
Published: June 2017

Purpose

The aim of this study was to determine if polysyllable accuracy in preschoolers with speech sound disorders (SSD) was related to known predictors of later literacy development: phonological processing, receptive vocabulary, and print knowledge. Polysyllables—words of three or more syllables—are important to consider because unlike monosyllables, polysyllables have been associated with phonological processing and literacy difficulties in school-aged children. They therefore have the potential to help identify preschoolers most at risk of future literacy difficulties.

Method

Participants were 93 preschool children with SSD from the Sound Start Study. Participants completed the Polysyllable Preschool Test (Baker, 2013) as well as phonological processing, receptive vocabulary, and print knowledge tasks.

Results

Cluster analysis was completed, and 2 clusters were identified: low polysyllable accuracy and moderate polysyllable accuracy. The clusters were significantly different based on 2 measures of phonological awareness and measures of receptive vocabulary, rapid naming, and digit span. The clusters were not significantly different on sound matching accuracy or letter, sound, or print concept knowledge.

Conclusions

The participants' poor performance on print knowledge tasks suggested that as a group, they were at risk of literacy difficulties but that there was a cluster of participants at greater risk—those with both low polysyllable accuracy and poor phonological processing.
Heat conductive h‐BN/CTPB/epoxy with enhanced dielectric properties for potential high‐voltage applications
Authors: Gong Ying , Zhou Wenying , Kou Yujia , Xu Li , Wu Hongju , Zhao Wei
Published: June 2017

To enhance the toughness and electrical insulation properties of cured epoxy, carboxyl‐terminated polybutadiene (CTPB) liquid rubber was used to modify epoxy in this study, and the thermal conductivity, mechanical and dielectric properties of modified epoxy were investigated. The results indicate that the CTPB‐epoxy exhibits higher impact strength and lower dielectric constant and loss compared with pure epoxy. Further, hexagonal boron nitride (hBN) was used to reinforce epoxy modified with 20 phr CTPB. It is found that compared with the hBN/epoxy under the same filler loading, the heat conductive hBN/CTPB/epoxy possesses a lower dielectric permittivity and dissipation factor in all frequency ranging from 102–107 Hz, a higher electrical resistivity and dielectric breakdown strength, and improved mechanical toughness. Therefore, the prepared hBN/CTPB/epoxy composites are potentially useful in practical electrical insulation applications.
Power‐constrained, spectral efficiency‐optimal, green cooperative device‐to‐device communication systems
Authors: Sainath Bitragunta
Published: June 2017

The author consider a relay‐assisted, two hop, cooperative device‐to‐device (D2D) communication system where a source device S transmits data to a destination device D using a non‐regenerative cooperative relay whose average transmit power is constrained. For the cooperative D2D system, the author consider the problem of optimally adapting the relay gain as a function of fading gains of S–R and R–D links to maximise fading‐averaged spectral efficiency. The author derive the spectral efficiency‐optimal relay gain adaptation policy (SERGAP), which determines optimal gain for the relay, and, analyse the fading‐averaged spectral efficiency of SERGAP. To gain more insights, the author derive upper bounds on the average spectral efficiency, and, also investigate its asymptotic behaviour using an insightful analysis. Furthermore, the author extend the fading‐averaged analysis to a system having multiple relays. The author also present numerical results for single relay and multiple relay systems and benchmark the proposed policy's performance with conventional and suboptimal relaying policies. The author show that SERGAP delivers higher average spectral efficiency than conventional relaying policies. Finally, spectral efficiency‐optimal relay placement for the proposed policy is also investigated via simulations, and, the author find that it is different from the suboptimal relaying policies.
Position error calculation of linear resolver under mechanical fault conditions
Authors: Daniar Ahmad , Nasiri‐Gheidari Zahra , Tootoonchian Farid
Published: June 2017

Position sensors are inseparable part of motion control systems. Linear resolvers (LRs) are electromagnetic position sensors that are suitable for high vibration, polluted environments. The accuracy of their detected position can be affected by different mechanical faults. In this study, variety of possible mechanical faults along with their mathematical index in LRs is introduced. Static eccentricity, dynamic eccentricity, inclined mover and run out error are the presented mechanical faults that are discussed independently and simultaneously. Then, three‐dimensional non‐linear, time‐stepping finite element method is employed to investigate the performance of the studied resolver under different mechanical faults. Finally, the prototype of the studied sensor is built. An experimental test setup is designed and built in order to measure the output characteristic of the LR under studied mechanical faults. Good correlation between the experimental and simulation results is obtained.
Facile synthesis of reduced graphene oxide/NH4V3O8 with high capacity as a cathode material for lithium ion batteries
Authors: Kou Lingjiang , Cao Liyun , Huang Jianfeng , Yang Jun
Published: June 2017

Owing to low‐electronic conductivity and long lithium ion diffusion path of NH4V3O8 limit its application for lithium‐ion batteries (LIBs). To overcome these limitation, a new nano‐composites material of NH4V3O8‐based have been successfully fabricated by a facial and environmental friendly approach, without the addition of any other template or surfactant. A facile hydrothermal route is employed to synthesised the reduced graphene oxide(rGO)/NH4V3O8 composites. Results show that the NH4V3O8 nano‐belt are well distributed on the surface of rGO nanosheets. The resulted rGO/NH4V3O8 nanocomposites exhibit a high capacity as a cathode material for LIBs in comparison with the bare NH4V3O8. When used as cathode material for LIBs, it delivers a maximum discharge capacity of 253 mAhg−1 at 15 mAg−1, 70 mAhg−1 larger than that of the pristine one. The enhanced electrochemical performance is attributed to the synergetic effects between NH4V3O8 and rGO, such as increased conductivity and shortened lithium ion diffusion path.
Spontaneous and piezo‐phototronics effect on geometrical shape of III‐Nitride wurtzite nanowires for high efficiency photovoltaic applications
Authors: Routray Soumya Ranjan , Lenka Trupti Ranjan
Published: June 2017

In this study, the influence of spontaneous and piezo‐phototronic effect on the performance of hexagonal and triangular III‐Nitride nanowire (NW) photovoltaic devices are investigated. The effect of stress/strain distribution on band structure of GaN/InxGa1‐x N/GaN core/shell/shell NW solar cell with hexagonal and triangular geometrical shape are also intensively investigated by numerical calculations. It is observed that NW solar cells possess a non‐uniform pattern of polarisation charges (PCs) due to complex distribution of strain and stress parameters depending upon growth orientations of NWs. Effect of PCs, especially due to piezo‐phototronic effect on the polar, semi‐polar and non‐polar planes of NW having Miller–Bravais indices of {000‐1}, {1‐101} and {1‐100} are discussed in detail, respectively. This numerical study not only provides the basic theoretical understanding about the spontaneous and piezo‐phototronic effect on III‐Nitride solar cell but also assists to obtain most optimised geometrical design to achieve high performance NW solar cell.
Fertility Status and Cancer
Authors: Brinton Louise
Published: June 2017

Elevated estradiol levels associated with ovulation-stimulating drugs used to treat infertility and ovarian punctures involved with in vitro fertilization (IVF) have led to concerns regarding long-term cancer effects. Assessed risks, however, have been contradictory. This may reflect small sample sizes and short follow-up times, as well as an inability of many studies to adjust for appropriate potential confounders, such as causes of infertility and parity. While early studies of ovulation-stimulating drugs suggested large increases in large ovarian cancer risk, more recent studies have not confirmed this. However, several investigations have noted risk elevations associated with drug use or IVF among women who remain nulliparous, possibly due to resistant infertility. Studies also suggest increases in borderline ovarian tumors, although the effects of surveillance bias are unclear. Investigations have not shown large increases in breast cancer risk, although a few studies suggest possible increases in select subgroups, including nulliparous women or those with high drug dosages in the distant past. A few studies have evaluated risks of other cancers (endometrium, colorectum, thyroid, and melanoma), without definitive results. Since women exposed to fertility treatments are just beginning to enter typical cancer age ranges, further well-designed investigations are needed to fully delineate long-term effects.
Male Infertility and Risk of Nonmalignant Chronic Diseases: A Systematic Review of the Epidemiological Evidence
Authors: Bonde Jens , Eisenberg Michael , Giwercman Aleksander , Hærvig Katia , Rimborg Susie , Vassard Ditte , Pinborg Anja , Schmidt Lone , Bräuner Elvira , Glazer Clara
Published: June 2017

The association between male infertility and increased risk of certain cancers is well studied. Less is known about the long-term risk of nonmalignant diseases in men with decreased fertility. A systemic literature review was performed on the epidemiologic evidence of male infertility as a precursor for increased risk of diabetes, cardiovascular diseases, and all-cause mortality. PubMed and Embase were searched from January 1, 1980, to September 1, 2016, to identify epidemiological studies reporting associations between male infertility and the outcomes of interest. Animal studies, case reports, reviews, studies not providing an accurate reference group, and studies including infertility due to vasectomy or malignancy were excluded. The literature search resulted in 2,485 references among which we identified seven articles fulfilling the eligibility criteria. Of these, four articles were prospective (three on risk of mortality, one on risk of chronic diseases) and three were cross-sectional relating male infertility to the Charlson Comorbidity Index. The current epidemiological evidence is compatible with an association between male infertility and risk of chronic disease and mortality, but the small number of prospective studies and insufficient adjustment of confounders preclude strong statements about male infertility as precursor of these outcomes.
Environmental Contaminants Affecting Fertility and Somatic Health
Authors: Chiang Catheryne , Mahalingam Sharada , Flaws Jodi
Published: June 2017

This review article summarizes the epidemiological findings published between 2011 and 2016 concerning bisphenol A (BPA), phthalates, dioxins, pesticides, air pollution, fracking chemicals, triclosan, and parabens and fertility parameters in men (i.e., semen volume, sperm concentration, sperm motility, and sperm morphology) as well as fertility parameters in women (i.e., cyclicity, fertility treatment outcomes), pregnancy outcomes (i.e., preterm birth, miscarriage), and reproductive disorders (i.e., polycystic ovary syndrome, endometriosis, and uterine fibroids). Overall, this review indicates that several environmental toxicants are significantly associated with reduced fertility parameters in men and women as well as several reproductive disorders in women. Although many studies reported that the selected exposures are associated with adverse fertility outcomes, several studies reported null associations. Thus, future studies are still needed to better elucidate the associations and potential mechanisms between these environmental chemicals and fertility outcomes in men and women.
Male Infertility and Risk of Cancer
Authors: Rogers Marc , Walsh Thomas
Published: June 2017

Male infertility is a complex and incompletely understood process that is thought to affect around 10% of the male population. Infertility is a complex interaction between genetics and environmental factors, which is increasingly being recognized as a potential marker of contemporary or future medical disease, including cancer. The best characterized association between infertility and cancer risk is that of testicular germ cell tumor, but increased risk for prostate cancer, melanoma, non-Hodgkin's lymphoma, and others have also been described. Much like infertility, the mechanism behind these associations is not completely understood. Several hypotheses have been put forth including testicular dysgenesis syndrome, chromosomal abnormalities, damaged DNA repair mechanisms, or Y chromosome abnormalities. With the use of advance reproductive techniques, more men are bypassing a male fertility specialist who may be positioned to diagnose or counsel patients regarding these risks.
Perilunate Dislocations and Perilunate Fracture Dislocations in the U.S. Military
Authors: Dunn John , Kusnezov Nicholas , Polfer Elizabeth , Orr Justin , Pirela-Cruz Miguel , Mitchell Justin , Koehler Logan
Published: June 2017

Background Perilunate dislocations and perilunate fracture dislocations (PLDs/PLFDs) are rare and often associated with poor outcomes. Heretofore, these outcomes have not been evaluated in a high-demand military population.

Questions/Purpose The purpose of this study was to evaluate the outcomes in a young, active population after sustaining PLD/PLFD injuries.

Patients and Methods We retrospectively reviewed the U.S. military service members who underwent surgical treatment for a PLD/PLFD (Current Procedural Terminology codes 25695 and 25685) between June 1, 2010, and June 1, 2014 through the Military Health System Management Analysis and Reporting Tool (M2) database, capturing patients with a minimum 2-year follow-up. Patient characteristics and outcomes were gathered; however, radiographic analysis was not possible.

Results In this study, 40 patients (40 wrists) were included with an average follow-up of 47.8 months. The average age was 28.8 years. Twenty-two injuries (55%) were PLFD and 22 (55%) cases involved the nondominant extremity. On initial presentation, 11 (27.5%) were missed and 50% of patients were presented with acute carpal tunnel syndrome. Range of motion (ROM) was 74% and grip strength was 65% compared with the contralateral wrist; 78% reported pain with activity and only 55% remained on active duty status at final follow-up. Injuries to the nondominant extremity were significantly more likely to experience a good to excellent outcome and regained a more ROM. Patients with ligamentous PLD had less pain at rest and were more likely to return to sport.

Conclusion Worse outcomes can be expected for PLD/PLFD of the dominant extremity, transscaphoid PLFD, greater arc injuries, and those undergoing pinning alone. A high-demand patient may expect worse functional results with a higher degree of limitation postoperatively.

Level of Evidence The level of evidence is therapeutic IV.
Predicting Triple-Negative Breast Cancer Subtype Using Multiple Single Nucleotide Polymorphisms for Breast Cancer Risk and Several Variable Selection Methods
Authors: Häberle Lothar , Hein Alexander , Rübner Matthias , Schneider Michael , Ekici Arif , Gass Paul , Hartmann Arndt , Schulz-Wendtland Rüdiger , Beckmann Matthias , Lo Wing-Yee , Schroth Werner , Brauch Hiltrud , Fasching Peter , Wunderle Marius
Published: June 2017

Introduction Studies of triple-negative breast cancer have recently been extending the inclusion criteria and incorporating additional molecular markers into the selection criteria, opening up scope for targeted therapies. The screening phases required for studies of this type are often prolonged, since the process of determining the molecular subtype and carrying out additional biomarker assessment is time-consuming. Parameters such as germline genotypes capable of predicting the molecular subtype before it becomes available from pathology might be helpful for treatment planning and optimizing the timing and cost of screening phases. This appears to be feasible, as rapid and low-cost genotyping methods are becoming increasingly available. The aim of this study was to identify single nucleotide polymorphisms (SNPs) for breast cancer risk capable of predicting triple negativity, in addition to clinical predictors, in breast cancer patients.

Methods This cross-sectional observational study included 1271 women with invasive breast cancer who were treated at a university hospital. A total of 76 validated breast cancer risk SNPs were successfully genotyped. Univariate associations between each SNP and triple negativity were explored using logistic regression analyses. Several variable selection and regression techniques were applied to identify a set of SNPs that together improve the prediction of triple negativity in addition to the clinical predictors of age at diagnosis and body mass index (BMI). The most accurate prediction method was determined by cross-validation.

Results The SNP rs10069690 (TERT, CLPTM1L) was the only significant SNP (corrected p = 0.02) after correction of p values for multiple testing in the univariate analyses. This SNP and three additional SNPs from the genes RAD51B, CCND1, and FGFR2 were selected for prediction of triple negativity. The addition of these SNPs to clinical predictors increased the cross-validated area under the curve (AUC) from 0.618 to 0.625. Age at diagnosis was the strongest predictor, stronger than any genetic characteristics.

Conclusion Prediction of triple-negative breast cancer can be improved if SNPs associated with breast cancer risk are added to a prediction rule based on age at diagnosis and BMI. This finding could be used for prescreening purposes in complex molecular therapy studies for triple-negative breast cancer.
Submucosal fibrosis in achalasia patients is a rare cause of aborted peroral endoscopic myotomy procedures
Authors: Wu Qiu-Ning , Xu Xiao-Yue , Zhang Xiao-Cen , Xu Mei-Dong , Zhang Yi-Qun , Chen Wei-Feng , Cai Ming-Yan , Qin Wen-Zheng , Hu Jian-Wei , Yao Li-Qing , Li Quan-Lin , Zhou Ping-Hong
Published: June 2017

Background and aims Peroral endoscopic myotomy (POEM) is now an established treatment for esophageal achalasia. The standard protocol ensures a smooth operation in most patients, but technical challenges and failures exist and little is known about the incidence, causes, and impact of aborted procedures. Here, using a large patient cohort, we attempted to answer these questions.

Methods All patients admitted for planned POEM between August 2010 and July 2015 underwent chart review. Aborted POEM was defined as the inability to finish the procedure after submucosal injection. The cause of the failure, clinical course, management, and follow-up data were analyzed.

Results Thirteen of the 1693 POEMs (0.77 %) were aborted. Out of the 13 failures, 12 (92.3 %) were due to severe submucosal fibrosis, which precluded tunneling, and one (7.7 %) was due to atrial fibrillation related to the electric current of the endoscopic knife. Submucosal fibrosis, prior Heller myotomy, and age ( ≥ 60 years) were related to technical failure, while a disease duration of ≥ 6 years, sigmoid esophagus, mucosal edema, and prior interventions were risk factors for the presence of fibrotic changes. In turn, fibrosis was correlated with a prolonged operation, longer hospital stay, more mucosal injuries, and more major perioperative adverse events. Finally, the yearly frequency of aborted POEMs decreased after the second year as operators became more experienced.

Conclusions Aborted POEM is a rare event and is largely due to the presence of submucosal fibrosis, which not only causes increased procedural difficulties, but also gives rise to major adverse events.
Characteristics of flow past a slender, emergent cylinder in shallow open channels
Authors: Heidari Mehdi , Balachandar Ram , Roussinova Vesselina , Barron Ronald M.
Published: June 2017

The complex wake created by an emergent cylinder with a large aspect ratio in a shallow open channel flow is studied experimentally using particle image velocimetry. The unique characteristics of the bed-mounted slender cylinder wake are analysed. Velocity fields, turbulence parameters, and wake development in shallow open channel flow are studied at two different Reynolds numbers and subcritical Froude numbers by carrying out measurements in different horizontal and vertical planes. In the mid-depth plane, velocity and turbulence statistics are independent of Reynolds number, while higher turbulence intensities and Reynolds shear stresses were observed in the near-bed plane for the low Reynolds number case. The narrower wake is observed in the near-bed plane due to the effect of the bed. Combined with stronger vertical velocity and turbulence intensities noted near the bed in the vertical midplane, this suggests increased activity of the vortex structures in the low Reynolds number case. Under shallow conditions, stronger disturbances of the free surface are observed for the case of high Reynolds and Froude numbers. The study also revisits the definition of the wake stability parameter and proposes a new definition which incorporates not only the bed friction but also the drag experienced by the cylinder.
Localized diabatization applied to excitons in molecular crystals
Authors: Jin Zuxin , Subotnik Joseph E.
Published: June 2017

Traditional ab initio electronic structure calculations of periodic systems yield delocalized eigenstates that should be understood as adiabatic states. For example, excitons are bands of extended states which superimpose localized excitations on every lattice site. However, in general, in order to study the effects of nuclear motion on exciton transport, it is standard to work with a localized description of excitons, especially in a hopping regime; even in a band regime, a localized description can be helpful. To extract localized excitons from a band requires essentially a diabatization procedure. In this paper, three distinct methods are proposed for such localized diabatization: (i) a simple projection method, (ii) a more general Pipek-Mezey localization scheme, and (iii) a variant of Boys diabatization. Approaches (i) and (ii) require localized, single-particle Wannier orbitals, while approach (iii) has no such dependence. These methods should be very useful for studying energy transfer through solids with ab initio calculations.
On quantitative errors of two simplified unsteady models for simulating unidirectional nonlinear random waves on large scale in deep sea
Authors: Wang Jinghua , Ma Qingwei , Yan Shiqiang
Published: June 2017

To investigate nonlinear random wave dynamics or statistics, direct phase-resolved numerical simulation of nonlinear random waves in deep sea on large-spatial and long-temporal scales are often performed by using simplified numerical models, such as those based on the Nonlinear Schrödinger Equation (NLSE). They are efficient and can give sufficiently acceptable results in many cases but they are derived by assuming narrow bandwidth and small steepness. So far, there has been no formula to precisely predict the quantitative errors of such simplified models. This paper will present such formulas for estimating the errors of enhanced NLSE based on the Fourier transform and quasi spectral boundary integral method when they are applied to simulate ocean waves on large-spatial and long-temporal scales (about 128 peak wavelengths and 1000 peak periods). These formulas are derived by fitting the errors of the simplified models, which are estimated by comparing their wave elevations with these obtained by using a fully nonlinear model for simulating the cases with initial conditions defined by two commonly used ocean wave spectra with a wide range of parameters. Based on them, the suitable regions for the simplified models to be used are shown.
Multiband Monte Carlo modeling of upconversion emission in sub 10 nm β-NaGdF4:Yb3+, Er3+ nanocrystals—Effect of Yb3+ content
Authors: Pawlik G. , Niczyj J. , Noculak A. , Radosz W. , Podhorodecki A.
Published: June 2017

In this work, we report the results of theoretical modeling supported and confirmed by experimentally measured emission, emission decay curves, and power dependent emission spectra for sub 10 nm β-NaGdF4:Er3+,Yb3+ nanocrystals with different Yb3+ content (0.5%-15%). For the theoretical analysis, we develop a stochastic Monte Carlo model which is based on two components: (i) formation of clusters composed of Er3+ ion and Yb3+ neighbors, which gives insight into the role of local parameters and (ii) a simplified kinetic model of excitation and relaxation phenomena in pairs of Er3+and Yb3+ ions. The quantitative agreement between experimental data and modeling was obtained for the relative emission ratio of upconversion luminescence in green, red, and blue spectral ranges. Theoretical predictions of impact of excitation pulse duration and pumping light power on upconversion luminescence are presented.
Assessment of mean-field microkinetic models for CO methanation on stepped metal surfaces using accelerated kinetic Monte Carlo
Authors: Andersen Mie , Plaisance Craig P. , Reuter Karsten
Published: June 2017

First-principles screening studies aimed at predicting the catalytic activity of transition metal (TM) catalysts have traditionally been based on mean-field (MF) microkinetic models, which neglect the effect of spatial correlations in the adsorbate layer. Here we critically assess the accuracy of such models for the specific case of CO methanation over stepped metals by comparing to spatially resolved kinetic Monte Carlo (kMC) simulations. We find that the typical low diffusion barriers offered by metal surfaces can be significantly increased at step sites, which results in persisting correlations in the adsorbate layer. As a consequence, MF models may overestimate the catalytic activity of TM catalysts by several orders of magnitude. The potential higher accuracy of kMC models comes at a higher computational cost, which can be especially challenging for surface reactions on metals due to a large disparity in the time scales of different processes. In order to overcome this issue, we implement and test a recently developed algorithm for achieving temporal acceleration of kMC simulations. While the algorithm overall performs quite well, we identify some challenging cases which may lead to a breakdown of acceleration algorithms and discuss possible directions for future algorithm development.
Stochastic surface walking reaction sampling for resolving heterogeneous catalytic reaction network: A revisit to the mechanism of water-gas shift reaction on Cu
Authors: Zhang Xiao-Jie , Shang Cheng , Liu Zhi-Pan
Published: June 2017

Heterogeneous catalytic reactions on surface and interfaces are renowned for ample intermediate adsorbates and complex reaction networks. The common practice to reveal the reaction mechanism is via theoretical computation, which locates all likely transition states based on the pre-guessed reaction mechanism. Here we develop a new theoretical method, namely, stochastic surface walking (SSW)-Cat method, to resolve the lowest energy reaction pathway of heterogeneous catalytic reactions, which combines our recently developed SSW global structure optimization and SSW reaction sampling. The SSW-Cat is automated and massively parallel, taking a rough reaction pattern as input to guide reaction search. We present the detailed algorithm, discuss the key features, and demonstrate the efficiency in a model catalytic reaction, water-gas shift reaction on Cu(111) (CO + H2O → CO2 + H2). The SSW-Cat simulation shows that water dissociation is the rate-determining step and formic acid (HCOOH) is the kinetically favorable product, instead of the observed final products, CO2 and H2. It implies that CO2 and H2 are secondary products from further decomposition of HCOOH at high temperatures. Being a general purpose tool for reaction prediction, the SSW-Cat may be utilized for rational catalyst design via large-scale computations.
Generation of zonal flows by coupled electrostatic drift and ion-acoustic waves
Authors: Kaladze T. D. , Kahlon L. Z. , Tsamalashvili L. V.
Published: June 2017

Generation of sheared zonal flow by low-frequency coupled electrostatic drift and ion-acoustic waves is presented. Primary waves of different (small, intermediate, and large) scales are considered, and the appropriate system of equations consisting of generalized Hasegawa-Mima equation for the electrostatic potential (involving both vector and scalar nonlinearities) and equation of parallel to magnetic field ions motion is obtained. It is shown that along with the mean poloidal flow with strong variation in minor radius mean sheared toroidal flow can also be generated. According to laboratory plasma experiments, main attention to large scale drift-ion-acoustic wave is given. Peculiarities of the Korteweg-de Vries type scalar nonlinearity due to the electrons temperature non-homogeneity in the formation of zonal flow by large-scale turbulence are widely discussed. Namely, it is observed that such type of flows need no generation condition and can be spontaneously excited.
Virpertron: A novel approach for a virtual cathode oscillator design
Authors: Dubinov Alexander E. , Petrik Alexey G. , Kurkin Semen A. , Frolov Nikita S. , Koronovskii Alexey A. , Hramov Alexander E.
Published: June 2017

In this paper, we propose a novel approach for the design of a virtual cathode oscillator. As a new concept, we suggest a microwave system containing an annular relativistic electron beam travelling through the drift space with dielectric inserts characterized by different values of permittivity. In this case, a virtual cathode which is the source of powerful electromagnetic oscillations forms at the junction of different dielectric materials. According to the mechanism of virtual cathode formation, we have called this device as a virpertron. We have carried out a detailed numerical investigation of virtual cathode formation features in this system via 3D electromagnetic PIC-simulation using CST Particle Studio. We have also studied the spectral properties of the microwave radiation generated by the virpertron.
Turbulent boundary layer response to large-scale wavy topographies
Authors: Hamed Ali M. , Castillo Luciano , Chamorro Leonardo P.
Published: June 2017

Flat-plate turbulent boundary layer adjustment to large-scale 2D and 3D wavy topographies was experimentally studied using high-resolution particle image velocimetry in a refractive-index-matching flume. The flow was characterized at a Reynolds number Re = 4×104, based on the channel half height and incoming free-stream velocity. Two ratios of amplitude (a) to incoming boundary layer thickness (δ0) were considered for each topography (a∕δ0 = 0.12 and 0.81). The 2D topography is described by a sinusoidal wave in the streamwise direction with an amplitude to wavelength ratio a∕λx = 0.05, while the 3D topography is defined with an additional wave superimposed in the spanwise direction. The results show that the spanwise variability of the topography leads to a much milder response in both a∕δ0 ratios. The regions of strong acceleration and deceleration over the crests and troughs of the topography are reduced over the 3D topography due to the alternate flow path around the 3D elements. Furthermore, the boundary layer thickness and integral parameters experienced milder variations over the 3D topography for both a∕δ0. The Reynolds shear stress shows distinctive evolution with downstream distance. In the 3D case, maximum Reynolds stress similar to those in the developed region is achieved within the first three wavelengths past the topographic change indicating that the dynamics of the downstream evolution is dominated by vertical diffusion and redistribution. This is in contrast with the 2D case with a∕δ0 = 0.12 where the Reynolds stress did not achieve the levels observed in the developed region.
Head-on collision of ion acoustic solitary waves in electron-positron-ion nonthermal plasmas for weakly and highly relativistic regimes
Authors: Alam M. S. , Hafez M. G. , Talukder M. R. , Hossain Ali M.
Published: June 2017

A comparative study of the interactions between nonlinear ion acoustic solitary waves (IASWs) propagating toward each other, and the electrostatic nonlinear propagation of IASWs, both for the weakly and relativistic regimes consisting of relativistic warm ions, nonthermal electrons, and positrons, is carried out. Two-sided Korteweg–de Vries (KdV) equations are derived using the extended Poincaré-Lighthill-Kuo (PLK) method to reveal the physical issues concerned. The effects of positron concentration, ion-electron temperature ratio, electron-positron temperature ratio, relativistic streaming factor, the population of electron, and positron nonthermality on the electrostatic resonances and their phase shifts are investigated for both regimes. It is found that the plasma parameters significantly modify the phase shifts, electrostatic resonances, hump-shaped electrostatic potential profiles, and the electric fields on the nonlinear propagation characteristics of IASWs. The results obtained may be useful for clarifications of interaction between IASWs in astrophysical and laboratory plasmas, especially in pulsar magnetosphere, laser produced, inertial confinement plasmas, and pulsar relativistic winds with supernova ejecta that produce nonthermal electrons, positrons, and relativistic ions.
Radial acceleration of geodesic acoustic modes in the presence of a temperature gradient
Authors: Palermo F. , Poli E. , Bottino A. , Biancalani A. , Conway G. D. , Scott B.
Published: June 2017

The global dynamics of geodesic acoustic modes (GAMs) is studied analytically and by means of gyrokinetic simulations for several equilibria with flat and nonuniform profiles. In particular, the effects of phase mixing via the continuum spectrum in the presence of a temperature gradient are investigated. We show that the frequency of GAM is not constant but can evolve in time because of the increase of the radial wavenumber. As a consequence, also the radial velocity of GAM increases in time. Thus, this study reduces the discrepancy between the linear theory and the experiments, in which strong velocities of GAM are generally observed. An estimate of phase and group velocity is given for simulations performed with experimental parameter values.
Thermal conductivity measurements of Yb:CaF2 transparent ceramics using the 3ω method
Authors: Sarthou J. , Duquesne J.-Y. , Becerra L. , Gredin P. , Mortier M.
Published: June 2017

This paper reports on the measurement of the thermal conductivity of ytterbium doped CaF2 transparent ceramics using the 3ω method. Samples with different doping levels were studied in a temperature range of 10 K to 310 K. The results for doped samples are very similar to those obtained for Yb:CaF2 single crystals with the same doping levels, which demonstrates an important improvement in the thermal properties of transparent ceramics. However, the results obtained for non-doped ceramics and single crystals differ for the maximum conductivity due to the presence of grain boundaries inside the ceramic. Theoretical calculations were also conducted using Callaway's model and are in a very good agreement with experimental results. The fitting parameters found tend to indicate that the introduction of a doping element in the lattice has more impact on thermal conductivity than the presence of grain boundaries in the material.
Flexible, wearable, and functional graphene-textile composites
Authors: Liu Ying , Zhang Kun-Ning , Zhang Ying , Tao Lu-Qi , Li Yu-Xing , Wang Dan-Yang , Yang Yi , Ren Tian-Ling
Published: June 2017

In this paper, a flexible, wearable, and functional graphene-textile composite is demonstrated. Laser scribing technology is applied to fabricate a graphene film. The thin layer of polydimethylsiloxane is covered on the surface of the graphene-textile film evenly, which would improve the abrasive resistance of the film, enhance the ability to adapt to environmental changes, and extend the service life, while maintaining the device's excellent flexibility and comfort. The graphene-textile composite can achieve constant temperature heating by controlling the input voltage, detect the human movement, and perceive the human pulse signal. The composite presents great commercial prospects and a large value in the medical, daily wear, and other areas that are closely related to human lives.
Temperature dependent photoreflectance study of Cu2SnS3 thin films produced by pulsed laser deposition
Authors: Raadik T. , Grossberg M. , Krustok J. , Kauk-Kuusik M. , Crovetto A. , Bolt Ettlinger R. , Hansen O. , Schou J.
Published: June 2017

The energy band structure of Cu2SnS3 (CTS) thin films fabricated by pulsed laser deposition was studied by photoreflectance spectroscopy (PR). The temperature-dependent PR spectra were measured in the range of T = 10–150 K. According to the Raman scattering analysis, the monoclinic crystal structure (C1c1) prevails in the studied CTS thin film; however, a weak contribution from cubic CTS (F-43m) was also detected. The PR spectra revealed the valence band splitting of CTS. Optical transitions at EA = 0.92 eV, EB = 1.04 eV, and EC = 1.08 eV were found for monoclinic CTS at low-temperature (T = 10 K). Additional optical transition was detected at EAC = 0.94 eV, and it was attributed to the low-temperature band gap of cubic CTS. All the identified optical transition energies showed a blueshift with increasing temperature, and the temperature coefficient dE/dT was about 0.1 meV/K.
4.5 W supercontinuum generation from 1017 to 3438 nm in an all-solid fluorotellurite fiber
Authors: Jia Zhixu , Yao Chuanfei , Jia Shijie , Wang Fang , Wang Shunbin , Zhao Zhipeng , Qin Guanshi , Ohishi Yasutake , Qin Weiping
Published: June 2017

All-solid fluorotellurite fibers are fabricated by using a rod-in-tube method. The core and cladding materials are TeO2-BaF2-Y2O3 (TBY) and AlF3-based glasses, respectively. Since the refractive index (∼1.46) of AlF3-based glass is much lower than that (∼1.84) of TBY glass, the zero-dispersion-wavelength of the fabricated fiber can be tuned from 2145 to 1507 nm by varying the fiber core diameter from 50 to 3 μm. By using a 0.6 m long all-solid fluorotellurite fiber with a core diameter of ∼7 μm as the nonlinear medium and a 2 μm femtosecond fiber laser as the pump source, 4.5 W supercontinuum (SC) generation from 1017 to 3438 nm is obtained for a launched pump power of ∼10.48 W. The corresponding optical-to-optical conversion efficiency is about 42.9%. In addition, no any damage of the fluorotellurite fiber is observed during the operation of the above SC light source. Our results show that all-solid fluorotellurite fibers are promising nonlinear media for constructing high power mid-infrared SC light sources.
Lateral capacity assessment of offshore wind suction bucket foundation in clay via centrifuge modelling
Authors: Wang Xuefei , Yang Xu , Zeng Xiangwu
Published: June 2017

The lateral bearing behaviors of suction bucket foundations for offshore wind turbines are investigated by centrifuge modelling in this paper. The centrifuge tests were performed in lightly over-consolidated clay and heavily over-consolidated clay, and three bucket foundation models with aspect ratios of 0.38, 0.5, and 1.3 were tested. The tests were force-controlled, and both static loads and cyclic loads were applied. In static tests, ultimate bearing capacities of suction bucket foundations were extracted from load-displacement curves as the first method, and the results were reinforced by stiffness-displacement curves. The displacement rates were calculated to find critical bearing capacities and ultimate bearing capacities of the foundations as the second method. The cyclic tests include cyclic loads with uniform and increased amplitudes. The accumulated lateral displacements and secant stiffnesses were discussed, and their variations with cycle numbers were studied.
Potential application of a homogeneous and anisotropic slab as an angle insensitive absorbing material
Authors: Wang Fang , Liu Chang , Liu Xiaoning , Niu Tiaoming , Wang Jing , Mei Zhonglei , Qin Jiayong
Published: June 2017

In this paper, a flat and incident angle independence absorbing material is proposed and numerically verified in the optical spectrum. A homogeneous and anisotropic dielectric slab as a non-reflecting layer is first reviewed, and a feasible realization strategy of the slab is then given by using layered isotropic materials. When the loss components of the constitutive materials are not zero, the slab will work as an angle insensitive absorbing layer, and the absorption rate augments with increase of the losses. As the numerical verifications, the field distributions of a metallic cylinder and a triangular metallic object individually covered by the designed absorbing layer are demonstrated. The simulation results show that the designed absorbing layer can efficiently absorb the incident waves with the property of incident angle independence at the operation frequency. This homogeneous slab can be used in one and two dimensional situations for the realization of an invisibility cloak, a carpet cloak and even a skin cloak, if it is used to conformally cover target objects.
Effects of hydrated sodium calcium aluminosilicate on growth performance, fatty liver, intestine morphology, and serum parameters of overfed geese
Authors: Tang Junwang , Lu Maxue , Fang Qianqian , Lu Feizhen , Shao Rongyi , Shen Junda , Lu Dailin , He Jun , Lu Lizhi , Niu Dong
Published: June 2017

In geese, overfeeding induces hepatic steatosis and makes the liver functions enhanced. Aluminosilicate absorbs toxins created by moulds in animal feeds and enhances nutrient absorption. In the present study, the effects of hydrated sodium calcium aluminosilicate (Improved HSCAS, Jumpstar) on the growth performance, fatty liver, serum parameters, and intestinal morphology of overfed Landes geese were evaluated. The study included two Control groups, a non-overfed Control (Control I) and an overfed Control (Control II), as well as a treatment group. The results showed that compared with the Control I group, liver weight, relative liver weight, abdominal fat weight, intestinal fat weight, villus height, total cholesterol, very low density lipoproteins, lipoprotein lipase, aspartate aminotransferase, IgM, and IgG in the HSCAS treatment group all significantly increased (P < 0.05) at Days 10 and 20. The villus height/crypt depth, triglycerides, cholinesterase, alanine aminotransferase, and serum IgA levels were higher than those in the Control I (P < 0.05) after 20 days of overfeeding. Compared with the Control II group, the relative abdominal fat weight, relative intestinal fat weight, and crypt depth in the HSCAS treatment group were significantly increased (P < 0.05) after 10 days of overfeeding, whereas villus height/crypt depth decreased (P < 0.05). Relative liver weight and IgA were higher in HACAS group after 20 days’ overfeeding (P < 0.05). HSCAS treatment also led to higher cholinesterase, very low density lipoproteins and decreased lipase, alanine aminotransferase (P > 0.05), and decreased aspartate aminotransferase levels than those in the Control II group (P < 0.05). In conclusion, HSCAS treatment had a beneficial effect on fatty liver production, intestinal development, and serum parameters in overfed Landes geese, which could enhance the health status of these geese.
Electropolymerisation of N-Ethylanilinium Trifluoroacetate Ionic Liquid into Poly(N-Ethylaniline) and Control of its Morphology
Authors: Abdelhamid Muhammad E. , Snook Graeme A. , Greaves Tamar L. , O'Mullane Anthony P.
Published: June 2017

In this paper, the electropolymerisation of pre-synthesised N-ethylanilinium trifluoroacetate, a protic ionic liquid (PIL), was carried out. The PIL served as the monomer precursor, solvent, and supporting electrolyte for the polymerisation process, and no additional acid was required due to the protic nature of the PIL. Two different morphologies of the poly(N-ethylaniline) were achieved by using different electropolymerisation approaches and the resultant films were soluble in the PIL precursor as well as a wide range of organic solvents. The use of anilinium based PILs, as polymerisation precursors, promises a greener approach for the production of polyanilines, as well as highly processable polymers.
Plant ionic relation and whole-plant physiological responses to waterlogging, salinity and their combination in barley
Authors: Falakboland Zhinous , Zhou Meixue , Zeng Fanrong , Kiani-Pouya Ali , Shabala Lana , Shabala Sergey
Published: June 2017

Waterlogging and salinity stresses significantly affect crop growth and global food production, and these stresses are often interrelated because waterlogging can lead to land salinisation by transporting salts to the surface. Although the physiological and molecular mechanisms of plant responses to each of these environmental constraints have been studied in detail, fewer studies have dealt with potential mechanisms underlying plant tolerance to the combined stress. This gap in knowledge is jeopardising the success of breeding programs. In the present work we studied the physiological and agronomical responses of 12 barley varieties contrasting in salinity stress tolerance to waterlogging (WL), salinity (NaCl) and combined (WL/NaCl) stresses. Stress damage symptoms were much greater in plants under combined WL/NaCl stress than those under separate stresses. The shoot biomass, chlorophyll content, maximum photochemical efficiency of PSII and shoot K+ concentration were significantly reduced under WL/NaCl conditions, whereas shoot Na+ concentration increased. Plants exposed to salinity stress showed lower damage indexes compared with WL. Chlorophyll fluorescence Fv/Fm value showed the highest correlation with the stress damage index under WL/NaCl conditions (r = –0.751) compared with other measured physiological traits, so was nominated as a good parameter to rank the tolerance of varieties. Average FW was reduced to 73 ± 2, 52 ± 1 and 23 ± 2 percent of the control under NaCl, WL and combined WL/NaCl treatments respectively. Generally, the adverse effect of WL/NaCl stress was much greater in salt-sensitive varieties than in more tolerant varieties. Na+ concentrations of the shoot under control conditions were 97 ± 10 µmol g–1 DW, and increased to 1519 ± 123, 179 ± 11 and 2733 ± 248 µmol g–1 under NaCl, WL and combined WL/NaCl stresses respectively. K+ concentrations were 1378 ± 66, 1260 ± 74, 1270 ± 79 and 411 ± 92 µmol g–1 DW under control, NaCl, WL and combined WL/NaCl stresses respectively. No significant correlation was found between the overall salinity stress tolerance and amount of Na+ accumulated in plant shoots after 15 days of exposure to 250 mM NaCl stress. However, plants exposed to combined salinity and WL stress showed a negative correlation between shoot Na+ accumulation and extent of salinity damage. Overall, the reported results indicate that K+ reduction in the plants under combined WL/NaCl stress, but not stress-induced Na+ accumulation in the shoot, was the most critical feature in determining the overall plant performance under combined stress conditions.