bluuebunny/crossref_metadata_2025_split huggingface dataset:
Local aggregation effect of CNT on the vibrational behavior of four‐parameter continuous grading nanotube‐reinforced cylindrical panels
Authors: Pourasghar A. , Yas M.H. , Kamarian S. 
Published: April 2013

AbstractFree vibrations analysis of four‐parameter continuously graded nanocomposite cylindrical panels reinforced by randomly oriented straight and local aggregation single‐walled carbon nanotubes (CNTs) are presented based on three‐dimensional theory of elasticity. The material properties of continuously graded carbon nanotube‐reinforced composites (CG‐CNTRCs) are estimated through the Eshelby–Mori–Tanaka approach based on an equivalent fiber. The generalized differential quadrature method as an efficient and accurate numerical tool is used to discretize the governing equations and impediment the boundary conditions. One of the contributions of this work is to illustrate the influence of the four parameters of power‐law distributions on the vibration behavior of functionally graded orthotropic cylindrical panels reinforced by nanotube. The properties of CG‐CNTRC are affected by its microstructure, especially the degree of CNT aggregation that is described by an aggregation coefficient. It is shown the degree of aggregation canseriously reduce the effective stiffness and frequency parameter. POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers
Electrical and thermal properties of polyethylene/silver nanoparticle composites
Authors: Jouni Mohammad , Boudenne Abderrahim , Boiteux Gisèle , Massardier Valérie , Garnier Bertrand , Serghei Anatoli 
Published: April 2013

AbstractThe concentration dependence of specific heat, electrical and thermal conductivities of nanocomposites based on high‐density polyethylene (HDPE) filled with silver nanoparticles have been investigated. The composites filled with high filler content show high electrical and thermal conductivities. The dielectric relaxation spectroscopy was used to investigate the electrical properties in the studied systems. The scaling law of electrical percolation was used for an exact estimation of the percolation threshold (Pc). A low electrical percolation threshold was found in the investigated composites. The rule of mixture was sufficient for the prediction of the specific heat dependence of HDPE–Ag nanocomposites as a function of the weight filler content. The basic models of the thermal conductivity have a tendency to underestimate the measured values for the low and high filler concentrations. POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers
Halloysite nanotube reinforced biodegradable nanocomposites using noncrosslinked and malonic acid crosslinked polyvinyl alcohol
Authors: Qiu Kaiyan , Netravali Anil N. 
Published: April 2013

AbstractHalloysite nanotubes (HNTs) based thin membrane‐like fully biodegradable nanocomposites were produced by blending individualized HNT dispersion with polyvinyl alcohol (PVA). Stable individualized HNT dispersion was obtained using several separation techniques, sequentially, prior to blending with PVA. PVA was crosslinked using malonic acid (MA) as crosslinker and phosphoric acid as catalyst, to increase the mechanical and thermal properties of HNT–PVA nanocomposites. Crosslinking was also intended to make PVA water‐insoluble and hence more useful in commercial applications. Examination of the composites indicated that HNTs were uniformly dispersed in both PVA as well as crosslinked PVA. Excellent mechanical properties of the HNT–PVA nanocomposites were achieved. These nanocomposites are intended to be composted at the end of their life rather than ending up in landfills as most of today's traditional petroleum based non‐biodegradable plastics. POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers
Natural Language Processing to identify pneumonia from radiology reports
Authors: Dublin Sascha , Baldwin Eric , Walker Rod L. , Christensen Lee M. , Haug Peter J. , Jackson Michael L. , Nelson Jennifer C. , Ferraro Jeffrey , Carrell David , Chapman Wendy W. 
Published: April 2013

ABSTRACTPurposeThis study aimed to develop Natural Language Processing (NLP) approaches to supplement manual outcome validation, specifically to validate pneumonia cases from chest radiograph reports.MethodsWe trained one NLP system, ONYX, using radiograph reports from children and adults that were previously manually reviewed. We then assessed its validity on a test set of 5000 reports. We aimed to substantially decrease manual review, not replace it entirely, and so, we classified reports as follows: (1) consistent with pneumonia; (2) inconsistent with pneumonia; or (3) requiring manual review because of complex features. We developed processes tailored either to optimize accuracy or to minimize manual review. Using logistic regression, we jointly modeled sensitivity and specificity of ONYX in relation to patient age, comorbidity, and care setting. We estimated positive and negative predictive value (PPV and NPV) assuming pneumonia prevalence in the source data.ResultsTailored for accuracy, ONYX identified 25% of reports as requiring manual review (34% of true pneumonias and 18% of non‐pneumonias). For the remainder, ONYX's sensitivity was 92% (95% CI 90–93%), specificity 87% (86–88%), PPV 74% (72–76%), and NPV 96% (96–97%). Tailored to minimize manual review, ONYX classified 12% as needing manual review. For the remainder, ONYX had sensitivity 75% (72–77%), specificity 95% (94–96%), PPV 86% (83–88%), and NPV 91% (90–91%).ConclusionsFor pneumonia validation, ONYX can replace almost 90% of manual review while maintaining low to moderate misclassification rates. It can be tailored for different outcomes and study needs and thus warrants exploration in other settings. Copyright © 2013 John Wiley & Sons, Ltd.
Power rating of photovoltaic modules including validation of procedures to implement IEC 61853‐1 on solar simulators and under natural sunlight
Authors: Kenny Robert P. , Viganó Davide , Salis Elena , Bardizza Giorgio , Norton Matthew , Müllejans Harald , Zaaiman Willem 
Published: April 2013

ABSTRACTThis paper describes the measurement of photovoltaic module performance over a range of temperatures and irradiances according to the international standard IEC 61853 Part 1. The purpose of this work is to assess the reproducibility of power matrix measurements obtained using two methods specified in the standard: under natural sunlight with a tracker, and with a solar simulator. A comparison of results using the third principal method (under natural sunlight without tracker) is also summarised for completeness. The same measurement techniques have been employed to measure four modules of different technologies, namely mono and poly crystalline Si, CdTe and CIS. The method used to vary the irradiance in the natural sunlight with tracker and solar simulator approaches is based on un‐calibrated mesh filters. The uniformity and effect on spectrum of the mesh filters have been studied, and the impact of these on the measurements estimated. Measurements from all methods are compared over as much of the ranges as possible. The results show that for all modules, the reproducibility is within the estimated measurement uncertainty. The suitability of the different methods is discussed in light of the results and the limitations of the various methods as applied to different modules technologies. On the basis of the results, parts of IEC 61853 Part 1 will be introduced into the ISO 17025 laboratory accreditation at the European Solar Test Installation (ESTI). Copyright © 2013 John Wiley & Sons, Ltd.
On the mechanical strength of monocrystalline, multicrystalline and quasi‐monocrystalline silicon wafers: a four‐line bending test study
Authors: Barredo Josu , Parra Vicente , Guerrero Ismael , Fraile Alberto , Hermanns Lutz 
Published: April 2013

ABSTRACTQuasi‐monocrystalline silicon wafers have appeared as a critical innovation in the PV industry, joining the most favorable characteristics of the conventional substrates: the higher solar cell efficiencies of monocrystalline Czochralski‐Si (Cz‐Si) wafers and the lower cost and the full square‐shape of the multicrystalline ones. However, the quasi‐monocrystalline ingot growth can lead to a different defect structure than the typical Cz‐Si process. Thus, the properties of the brand new quasi‐monocrystalline wafers, based on low and high crystal defect densities, have been for the first time studied from a mechanical point of view, comparing their strength with that of both Cz‐Si monocrystalline and typical multicrystalline materials. The study has been carried out employing the four line bending test and simulating them by means of FE models. For the analysis, failure stresses were fitted to a three‐parameter Weibull distribution. High mechanical strength was found in all the cases. However, the quasi‐monocrystalline wafers characterized by large density of bulk defects, due to the noticeable density of extended defects, showed lower fracture tensions. Copyright © 2013 John Wiley & Sons, Ltd.
Synthesis and photovoltaic properties of amorphous polymers based on dithienylbenzothiadiazole‐triphenylamine with hexyl side chains on different positions of thienyl groups
Authors: Yasuda Takeshi , Shinohara Yuki , Matsuda Takaaki , Han Liyuan , Ishi‐i Tsutomu 
Published: April 2013

ABSTRACTWe synthesized and characterized three new amorphous dithienylbenzothiadiazole (TBT)‐triphenylamine (TPA) polymers for application in bulk‐heterojunction (BHJ) organic photovoltaic (OPV) cells. Poly(3HTBT‐TPA) has hexyl side chains on the thienyl groups (pointing toward the benzothiadiazole (BTD) unit), and poly(4HTBT‐TPA) has hexyl side chains on the thienyl groups (pointing outward from the BTD unit). The incident photon to current conversion efficiencies (IPCEs) in the region from 550 to 650 nm for the OPV cells prepared using poly(4HTBT‐TPA) were higher than those for the OPV cells prepared using poly(3HTBT‐TPA) because the absorption spectrum for the poly(4HTBT‐TPA) has a slightly red‐shifted absorption edge. We also demonstrated that the poly(4HTBT‐TPA)‐based OPV performance is independent of the fabrication process, so using an amorphous film to fabricate BHJ OPV cells offers great advantages over using a polycrystalline film in terms of the high reproducibility of the OPV performance. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2536–2544
Improved phase separation in polymer solar cells by solvent blending
Authors: Kästner Christian , Muhsin Burhan , Wild Andreas , Egbe Daniel A. M. , Rathgeber Silke , Hoppe Harald 
Published: April 2013

ABSTRACTThe effect of solvent blending on the performance of an anthracene‐containing poly(p‐phenylene‐ethynylene)‐alt‐poly(p‐phenylene‐vinylene) backbone‐based donor polymer with asymmetrically substituted branched 2‐ethylhexyloxy and methyloxy side‐chains in bulk heterojunction solar cells is reported. This copolymer yields relatively high open‐circuit voltages with fullerene‐based electron acceptors. We systematically studied the thin‐film blend morphology and solar cell performance as a function of solvent composition (chlorobenzene to chloroform ratio) and polymer to [6,6]‐phenyl C61‐butyric acid methylester (PCBM) ratio. We combined photophysical investigations with atomic force microscopy and grazing incidence wide‐angle X‐ray scattering to elucidate the solid‐state morphology in thin films. In the investigated polymer system, the blend morphology becomes independent of the supporting solvent for high PCBM concentrations. Deposition from solvent blends rather than from pure chlorobenzene facilitates the beneficial phase separation between polymer and PCBM, leading to improved charge transport properties (short‐circuit currents) at lower PCBM concentrations. © 2013 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2013, 51, 868–874
Post‐traumatic growth among an ethnically diverse sample of adolescent and young adult cancer survivors
Authors: Arpawong T. Em , Oland Alyssa , Milam Joel E. , Ruccione Kathleen , Meeske Kathleen A. 
Published: April 2013

AbstractObjectiveAlthough some survivors of childhood cancer report significant psychosocial distress, many also report having derived benefits, or post‐traumatic growth (PTG), from their cancer experience. This study examines PTG and its correlates among an ethnically diverse sample of adolescent/young adult (AYA) cancer survivors who have recently completed treatment.MethodsSurvivors of childhood cancer (n = 94; 47% Hispanic), ages 11–21 and within 6 months of completing cancer therapy, were recruited from three pediatric cancer centers. Participants completed a structured interview that assessed demographics, PTG, post‐traumatic stress symptoms, health‐related quality of life, optimism, and depressive symptoms. Diagnosis/treatment information was collected from each patient's medical record. Multiple regression analyses were used to identify significant correlates of PTG.ResultsThe majority of survivors reported positive growth. PTG was positively associated with psychosocial functioning and post‐traumatic stress symptoms and inversely associated with physical functioning and depressive symptoms. PTG was significantly lower among survivors of bone tumors (vs. survivors of other cancers) and Hispanic survivors who primarily spoke English at home (vs. Hispanics who primarily spoke Spanish at home and non‐Hispanics). PTG was not significantly related to age, sex, optimism, cancer treatment modality, duration of treatment, or treatment intensity.ConclusionsThe AYA survivors commonly reported PTG in the immediate aftermath of cancer treatment. Findings regarding PTG among more acculturated Hispanic and bone tumor AYA survivors may help to inform risk‐adapted clinical interventions, among those transitioning from active treatment to post‐treatment surveillance, to mitigate negative long‐term sequelae and enhance positive psychosocial adaptation from the cancer diagnosis and treatment. Copyright © 2013 John Wiley & Sons, Ltd.
Dispersion theory of nucleon Compton scattering and polarizabilities
Authors: Schumacher M. , Scadron M.D. 
Published: April 2013

AbstractA status report on the topic nucleon Compton scattering and polarizabilities is presented with emphasis on the scalar t‐channel as entering into dispersion theory. Precise values for the polarizabilities are obtained leading to αp = 12.0 ± 0.6 (12.0), βp= 1.9∓ 0.6 (1.9), αn= 12.5 ± 1.7 (13.4), βn= 2.7 ∓ 1.8 (1.8) in units of 10−4 fm3 and γ(p)π= −36.4 ± 1.5 (−36.6), γ(n)π= 58.6 ± 4.0 (58.3), (γ(p)0 = −0.58 ± 0.20), (γ(n)0 = +0.38 ± 0.22) in units of 10−4 fm4, for the proton (p) and neutron (n), respectively. The data given with an error are recommended experimental values with updates compared to [1] where necessary, the data in parentheses are predicted values. These predicted values are not contained in [1], but are the result of a newly developed analysis which is the main topic of the present paper. The most important recent discovery is that the largest part of the electric polarizability and the total diamagnetic polarizability of the nucleon are properties of the σ meson as part of the constituent‐quark structure, as expected from the mechanism of chiral symmetry breaking. This view is supported by an experiment on Compton scattering by the proton carried out in the second resonance region, where a large contribution from the σ meson enters into the scattering amplitudes. This experiment led to a determination of the mass of the σ meson of mσ= 600± 70 MeV. From the experimental αp and predicted differences (αn‐αp) neutron polarizabilities in the range αn = 12.0 – 13.4 are predicted, where the uncertainties are related to the f0(980) and a0(980) scalar mesons.
Layer transfer process assisted by laser scribing for thin film solar cells based on epitaxial foils
Authors: Matte Eric , van Nieuwenhuysen Kris , Depauw Valerie , Govaerts Jonathan , Gordon Ivan 
Published: April 2013

AbstractThe lift‐off step of a layer transfer process for the production of thin‐film solar cells using a double porous layer is studied in detail. The goal is to locally weaken the thin film to improve the detachment. A UV nanosecond pulse laser is used to induce the weakening by scribing trenches. A relation between the pulse fluence, the number of pulses per point and the ablated area is found and used to predict the ablation depth. The grooving step is applied at different points in the process chain. The most suitable grooves are obtained when the scribing process is done after front‐side processing of the attached thin film and before the bonding step. A yield of around 80% is obtained for samples that went through the process chain up to the detachment step, by using the optimized process conditions. magnified imageSEM of the mother substrate (right) and the remaining of the thin film (left) after detachment of the useful foil area. The white points on the substrate are the leftover of the pillars from the weak layer.
Comparative analysis of mechanical properties of Si substrates processed by different routes
Authors: Gouttebroze Sylvain , Lange Hans Ivar , Ma Xiang , Gløckner Ronny , Emamifard Behnaz , Syvertsen Martin , Vardavoulias Michalis , Ulyashin Alexander 
Published: April 2013

AbstractThe purpose of this work is to check the potential of innovative processes for the Si wafers production toward the solar cell industry. Studies have been focused on a comparative analysis of mechanical properties of such wafers, since: (i) reduced wafer strength leads to a high breakage rate during subsequent handling and solar cell processing steps, (ii) cracking of solar cells has become one of the major sources of solar module failure and rejection. Therefore while developing new types of wafer materials and processing, it is essential to assess the mechanical strength of the wafers. Mechanical properties of several innovative Si based substrates are estimated. The bending strength measurements of the silicon wafer are performed using the ring‐on‐ring set‐up coupled with a numerical model to obtain estimate of the fracture stress and the Weibull parameters of the fracture distribution. Results are presented for five different materials: sintered Si powder, standard multi‐crystalline Si, Czochralski monocrystalline Si, and two types of thermal sprayed Si wafers.
Effects of pressure on photo‐induced formation of Se and Te clusters in II–VI compounds
Authors: Lindberg G. P. , Tallman R. E. , Lauck R. , Cardona M. , Liu X. , Furdyna J. K. , Weinstein B. A. 
Published: April 2013

AbstractThe tendency for clusters of crystalline Se or Te to form in the zincblende (ZB) phases of ZnSe, ZnTe, and CdSe is investigated as a function of applied pressure and under exposure to laser light. We find that nanoclusters of these elements in the trigonal phase form at pressures of >4.8 GPa for ZnSe and 0–0.9 GPa for ZnTe under exposure to moderate fluxes of sub‐bandgap light ∼102 W mm−2. The appearance of the A1 Raman peaks of Se or Te, clearly identified by their negative pressure shifts, provide definitive evidence of the cluster formation. Several mis‐assignments of these peaks in the literature are noted. For CdSe, the phase transition at 2.5 GPa leads to ambiguity in our results. Some mechanisms for the formation of Se (Te) clusters in II–VI solids are briefly considered.
Magnetotransport in Zn1−xMnxSe:Cl under hydrostatic pressure
Authors: Petznick Steve , Hetterich Michael , Klar Peter J. 
Published: April 2013

AbstractPressure dependent magnetotransport measurements have been carried out on a chlorine‐doped Zn0.98Mn0.02Se epilayer with a carrier concentration below the critical concentration of the metal‐insulator transition (MIT). The large positive magnetoresistance at low temperatures can qualitatively be related to the giant Zeeman splitting of the donor states. The increase of the resistivity and the magnetoresistance effects under hydrostatic pressure is mainly related to the increase of the electron effective mass in the conduction band. This increase of the effective mass is the reason for an increase of the donor depth and a corresponding shrinkage of the donor wavefunction, which in turn leads to a narrowing of the impurity band (IB). The splitting of this narrow IB, which results from an applied pressure, is the main reason for the enhancement of the large positive magnetoresistance effects under pressure.
Pressure tuning of high‐power laser diodes in the 720–1540 nm range
Authors: Dybala Filip , Bercha Artem , Klimczak Mariusz , Piechal Bernard , Ivonyak Yurii , Trzeciakowski Witold A. 
Published: April 2013

AbstractLaser diodes with output powers of 1–2 W and emission wavelengths of 808, 860, 975, 1060, 1120, 1210, and 1540 nm have been tuned with pressure up to 2 GPa. Pressure tuning might become a practical method for tuning near‐infrared lasers in spectroscopic applications, such as photoluminescence excitation, photoreflectance, and resonant Raman scattering, as well as in applications as optical pumps at unique wavelengths.
Use of dynamic compression to probe semiconductor response at large strains
Authors: Grivickas P. , McCluskey M. D. , Gupta Y. M. 
Published: April 2013

AbstractLarge strains in semiconductors are expected to be more common in future electronic devices utilizing nanostructure components. Hydrostatic pressure (HP) and uniaxial stress (US) loading have inherent limitations for probing the desired strain conditions. Uniaxial strain loading, achieved in dynamic compression experiments, is particularly attractive for attaining well‐defined, large strains and to complement HP and US loading. Recent dynamic compression studies on III–V semiconductors (GaN, GaP, and GaAs) are summarized to review notable findings ranging from improved deformation potentials to free carrier properties. These findings demonstrate the benefits of dynamic compression experiments for semiconductor research.
Origin of the visible light absorption of Co2+ and NH4+ co‐doped hydrogen titanate nanotube thin films
Authors: An Yongliang , Li Zhonghua , Wang Dongjun , Shen Jun 
Published: April 2013

AbstractHydrogen titanate nanotube (HTNT) thin films were synthesized by hydrothermal method and then Co2+ and NH4+ co‐doped hydrogen titanate nanotube (Co, N‐HTNT) thin films were prepared by ion‐exchange method. The Co, N‐HTNT thin films exhibit strong absorption in the visible light range compared with the HTNT and NH4+ doped hydrogen titanate nanotube (N‐HTNT) thin films. The first‐principles calculations reveal that NH4+ doping has no effect on the visible light absorption of HTNTs. The red shift of Co, N‐HTNTs is only due to the mixture of the Co 3d and O 2p states in the top of the valence band, which results in the band gap narrowing. Relative to HTNTs and N‐HTNTs, both the valence band maximum (VBM) and conduction band minimum (CBM) of Co, N‐HTNTs shift to lower potential based on the valence band XPS spectra. Furthermore, the up‐shift of the VBM is much larger than that of the conduction band, which can result in band gap reduction explaining the origin of the visible light absorption of Co, N‐HTNTs.