bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of In Situ Characterization Techniques for Pavement Applications of Portland Cement-Stabilized Soil
Authors: Griffin Jonathon R. , Jersey Sarah R. 
Published: April 2011

Abstract
Evaluation of the structural capacity of in-service pavements with a cement-stabilized soil layer provides a unique challenge. Properties required to assess the structural capacity include strength and stiffness of the material. Traditionally these parameters are determined from laboratory testing of samples obtained in situ. Obtaining, transporting, and testing material samples are expensive procedures often not possible due to the low strength of some stabilized blends. The U.S. Army Engineer Research and Development Center investigated the potential of implementing a series of portable tools to rapidly obtain these parameters in the field. Field tests were performed at three sites, and samples were recovered and subjected to laboratory testing. Regression analyses were used to determine the existence of linear relationships between the results of the laboratory and field testing. Statistical analyses were performed to determine the validity of applying select relationships from literature and those developed in this study. The development of a reliable evaluation procedure was hindered by the inherent variability of stabilized materials. However, the devices investigated in this study should be considered for quality control testing on new construction with portland cement-stabilized soil.
Influenza A/H1N1 MF59-Adjuvanted Vaccine in Preterm and Term Children Aged 6 to 23 Months
Authors: Esposito Susanna , Pugni Lorenza , Daleno Cristina , Ronchi Andrea , Valzano Antonia , Serra Domenico , Mosca Fabio , Principi Nicola 
Published: April 2011

OBJECTIVE:This study was designed to evaluate the immunogenicity, safety, and tolerability of a monovalent 2009 pandemic influenza A/H1N1 MF59-adjuvanted vaccine in children aged 6 to 23 months who had different gestational ages (GAs) at birth.METHODS:The study involved 105 children: 35 preterm subjects with a GA of &lt;32 weeks; 35 preterm subjects with a GA of 32 to 36 weeks; and 35 term subjects with a GA of 37 to 42 weeks. Each child received 2 intramuscular vaccine doses (Focetria [Novartis, Siena, Italy]): dose 1 at enrollment and dose 2 after 4 weeks (28 ± 2 days). Serum samples for antibody measurements were collected immediately before administration of dose 1, before administration of dose 2 (28 ± 2 days after baseline), and 4 weeks later (56 ± 2 days after baseline). Local and systemic reactions were assessed during the 14 days after each vaccination.RESULTS:Of the 101 children who completed the study 32 out of 34 preterm subjects with a GA of &lt;32 weeks, all of the preterm subjects with a GA of 32 to 36 weeks, and all of the term subjects seroconverted and were seroprotected after the first vaccine dose. Local and systemic tolerability was good in all of the groups, but fever was significantly more common after the first dose than after the second dose (P &lt; .05), and there were no between-group differences.CONCLUSIONS:A single dose of 2009 pandemic influenza A/H1N1 MF59-adjuvanted vaccine evoked a significant immune response against pandemic influenza A/H1N1 virus in children aged 6 to 23 months even if their GA was &lt;32 weeks. The vaccine had a good safety and tolerability profile.
Growth and Characterization of Shape-Controlled Single Crystals by a Micro-pulling-down Method
Authors: Yokota Yuui , Tanaka Hidehiko , Sato Masato , Chani Valery , Tota Kazushige , Onodera Ko , Yanagida Takayuki , Yoshikawa Akira 
Published: April 2011

ABSTRACTShape-controlled CaF2 and sapphire crystals were grown by a micro-pulling-down (μ-PD) method and the crystallinities were investigated. By the μ-PD method with crucibles which have special configurations, circular tube-shaped CaF2 crystal, square tube-shaped CaF2 crystal and square tube-shaped sapphire crystal with high transparency were obtained. The grown crystals indicated a single phase of CaF2 and Al2O3 in the XRD measurements. X-ray rocking curve of square tube-shaped sapphire indicated the crystal has no mosaic structure in the crystal and it has high crystallinity comparable to crystals grown by Cz method.
Study of Mechanical Responses and Thermal Expansion of CNF-modified Polyester Nanocomposites Processed by Different Mixing Systems
Authors: Hossain Muhammad E. , Hossain Mohammad K. , Hosur Mahesh , Jeelani Shaik 
Published: April 2011

ABSTRACTIn this study, different dispersion techniques such as sonication at high frequency, mechanical mixing, and magnetic stirring methods were employed to infuse 0.1 to 0.4 wt.% carbon nanofiber (CNF) into polyester matrix to study the influence of CNF on mechanical and thermal properties of the polyester nanocomposites. Dispersion of CNF studied using scanning electron microscopy (SEM) micrographs revealed excellent dispersion of CNF using sonication when 0.2 wt.% CNF was mixed in polyester resulting in enhanced mechanical response. On the other hand, agglomerations were observed in samples prepared with other mixing methods. Polyester with 0.2 wt.% CNF samples prepared by sonication resulted in 88% and 16% increase in flexural strength and modulus, respectively, over neat samples. Quasi-static compression tests showed similar increasing trend with addition of 0.2 wt.% CNF. Dynamic mechanical analysis (DMA) showed 35% and 5 °C improvement in the storage modulus and glass transition temperature (Tg), respectively, in the 0.2 wt.% loaded samples. Thermal mechanical analysis (TMA) performed on neat and samples with 0.2 wt.% CNF showed lower coefficient of thermal expansion (CTE) in nanophased sample compared to neat. Fracture morphology evaluated using SEM revealed relatively rougher surface in CNF-loaded polyester compared to neat as a result of better interaction between fiber and matrix due to the presence of CNF.
In Situ Synthesis and Integration of Polymer Electrolytes in Nanostructured Electrodes for Photovoltaic Applications
Authors: Nejati Siamak , Lau Kenneth K. S. 
Published: April 2011

ABSTRACTThe conventional dye sensitized solar cell (DSSC) is limited by the use of a liquid electrolyte that is prone to leakage and evaporation. Efforts to replace the liquid with a solid equivalent have been met with difficulties in penetrating the mesoporous TiO2 nanostructured photoanode with liquid processing, particularly for photoanode layer thickness greater than 2 μm. Here, initiated chemical vapor deposition (iCVD) is successfully applied to directly synthesize and fill the pores of the mesoporous TiO2 network of up to 12 μm thickness with poly(2-hydroxyethyl methacrylate) (PHEMA) polymer electrolyte. Comparing with equivalent liquid electrolyte cells, DSSCs integrated with PHEMA polymer electrolyte showed consistently higher open circuit voltage, which is attributed to a decrease in electron recombination with the redox couple at the electrode-electrolyte interface.
Magnetic Polypropylene Nanocomposites Reinforced with In-situ Fabricated Iron Oxide Nanoparticles
Authors: Zhu Jiahua , Wei Suying , Guo Zhanhu 
Published: April 2011

ABSTRACTPolypropylene(PP)/Fe2O3 nanocomposites are fabricated using an in-situ method to uniformly disperse the magnetic nanoparticles (NPs) in polymer matrix. Maleic anhydride functionalized PP (f-PP) with different molecular weight is used as surfactant to stabilize the in-situ produced nanoparticles. The thermal behavior of PP and its nanocomposites with the incorporation of small amount f-PP is studied with thermal gravimetric analysis (TGA). The results show that the onset degradation temperature is increased by ~117 oC with the addition of NPs. Both melt rheology and transmission electron microscopy are used to investigate the NPs dispersion. Strong saturated magnetization (Ms) is observed after introducing f-PP to the nanocomposites through protecting the as-formed NPs from oxidation.
Gelation, Electrical Conductivity and Elasticity of PAM- MWNT
Authors: Evingur Gulsen A. , Pekcan Önder 
Published: April 2011

ABSTRACTPolyacrylamide- Multiwalled carbonnanotube (PAM- MWNT) composites were prepared via free radical crosslinking copolymerization with different amounts of MWNT varying in the range between 0.1 and 15 wt. %. PAM- MWNT composite gels were characterized by fluorescence, dielectric spectroscopy and the tensile testing technique. A small content of doped nanotubes dramatically changed gelation time, conductivity and young modulus, respectively. The gel fraction exponent,βof PAM- MWNT composite gels were measured for various monomer and MWNT concentrations and observed that the gel fraction exponentβagrees best with the percolation theory for various amounts of PAM- MWNT. These polymer systems which are initially of an isolator character are doped with carbon nanotubes of nano dimensions and when the amount of this addition exceeds a critical value (0.3 wt. % MWNT) known as the percolation threshold, then composite gel systems with carbon nanotubes become electrically conducting structures with a critical exponent aroundr=2 which is close to the theoretical prediction of this value in 3D percolated system as known random resistor network. The observed elasticities are decreased above 3 wt. %MWNT with critical exponent aroundy=0.72 which is indicative of a transition from liquid-like to solid-like viscoelastic behavior.
Microwave Metamaterials Containing Magnetically Soft Microwires
Authors: Panina L. V. , Ipatov M. , Zhukova V. , Estevez J. , Zhukov A. 
Published: April 2011

ABSTRACTThis paper discusses a new type of wire media based on amorphous ferromagnetic microwires. The combination of two effects, namely, a strong dispersion of the effective permittivity in metallic wire composites (resonance or plasmonic type) and giant magnetoimpedance effect in wires will result in unusual property that an effective dielectric response may strongly depend on the wire magnetization which can be changed with different external stimuli. We have demonstrated the effect of the external magnetic field on microwave response from composites containing CoFeSiBCr amorphous wires in free space at microwave frequency.
Melt-Quench Formed Smectic Phase in iPP/CNT Nanocomposites and its Re-Crystallization
Authors: Georgiev Georgi , Cabrera Yaniel , Wielgus Lauren , Schoen Scott , Ivy Devin , Cebe Peggy 
Published: April 2011

ABSTRACTThe largest commercial application of carbon nanotubes (CNT) are their polymer nanocomposites (PNCs). This motivates detailed studies of the interactions between CNTs and polymers and the ways the CNTs influence the crystallization behavior and structure of PNCs. We have chosen isotactic polypropylene (iPP) as one of the best model systems because of its ability to form a smectic liquid crystal phase. We studied iPP/CNT nanocomposites with CNT concentrations ranging from 0.01 to 5% per weight. We prepared films by compression molding and quenching in a mixture of isopropyl alcohol and dry ice. Some of the formed smectic liquid crystalline (LC) phase of iPP/CNT PNCs persisted to temperatures higher than the last melting temperature for iPP crystals. By means of differential scanning calorimetry we corroborated the existence of the LC phase in the nanocomposites and studied the impact of multi-walled carbon nanotubes on its melting and re-crystallization. We used a polarizing optical microscopy to reconfirm our DSC data.
Laser assisted fabrication of porous polymer MEMS with nano structured additives
Authors: Shishkovsky Igor V. , Morozov Yuri G. 
Published: April 2011

ABSTRACTSelective laser sintering (SLS) process was used to obtain nanostructured porous 3D objects consisting of Ni or/and Cu nanoclusters enveloped with a polycarbonate (PC) matrix for M/NEMS applications. The liquid phase SLS process was performed in air or Ar. The powder mixtures of Ni + PC in proportions 1:1, 1:2 (Ni particle size ranged from 27 to 184 nm) and Cu + PC = 1:9, 1:4, 3:7 (Cu particle size ranged from 76 to 90 nm) and a cw YAG:Nd+3 laser (P = 4–10 W) with defocused laser beam were used. Optimal regimes of laser treatment as monolayer as layerwise 3D part manufacturing in above mention nano compositions were determined. The scanning electronic microscopy (SEM) equipped EDX and qualitative XRD analysis showed that content and size of nanoparticles are remained unaffected after the liquid-phase sintering. It was shown a principle possibility of functional graded 3D parts fabrication via the interleaving of the metal - polymer powdered compositions with Ni and/or Cu additives, which ensures the nano particle sizes conservation. Proposed approach is opened a new way by deliberated M/NEMS device synthesis. Alternation of ferromagnetic and non-magnetic layers with Ni and/or Cu core – polymer shell structures was provided the interesting electro-physical properties of such devices.
Layer-by-layer Stacking Method for 3-D Nano Structure Fabrication Using Block Copolymer Self Assembly
Authors: Warisawa Shin’ichi , Kanameda Ryosuke , Kometani Reo , Ishihara Sunao 
Published: April 2011

ABSTRACTIn this paper, we present layer-by-layer stacking method to fabricate self-assembled structures of block copolymers (BCP) toward the out-of-plane direction. Layer-by-layer stacking is realized by transferring a BCP film on one substrate to another. Specifically, a water-soluble polymer film is coated on the former substrate, which is placed and fixed in contact with a target substrate. Consequently, the BCP film is released from the substrate and transferred to the target substrate when immersed in de-ionized water. In our experiment, PS-b-PMMA is used to form and transfer self-assembled structures, and polyvinyl alcohol is used as a water-soluble polymer. We prepared two kinds of target substrates; one has horizontal cylindrical structures by BCP self assembly, and the other has groove structures by EB lithography. In the case of BCP patterned substrate, BCP film with vertical cylindrical structures is transferred onto the line structures of BCP. In the case of EB lithography patterned substrate, BCP film with vertical cylindrical structures is transferred in a doubly suspended condition. Furthermore, vertical and horizontal cylindrical structures are also observed to align along the grooves.
Crystallization Kinetics in Isotactic Polypropylene Films with Carbon Nanotubes
Authors: Georgiev Georgi , Schoen Scott , Ivy Devin , Wielgus Lauren , Cabrera Yaniel , Cebe Peggy 
Published: April 2011

ABSTRACTPolymer nanocomposites are the largest commercial application for carbon nanotubes (CNTs) which determines the interest in their effect on crystallization processes of polymers. We chose Isotactic Polypropylene (iPP) as one of the most widely used polymers. Nanocomposites with multiwall carbon nanotubes (MWCNTs) 0-5% by weight were studied, using differential scanning Calorimetry to measure the crystal nucleation and kinetics effects of MWCNTs. Isothermal crystallization at 138°C was performed and the data were analyzed using Avrami analysis. We obtained results for the effect of MWCNTs on the crystallization kinetics. The Avrami analysis showed a dramatic increase in the crystallization rate constant and constancy of the Avrami exponent with increase of the CNTs concentration. The full width at half maximum (FWHM) of the heat flow exotherm and the peak time for crystallization (tp) change dramatically. The crystallinity shows a slight variation with the CNTs concentration dipping at 2% CNTs which can be explored further at higher concentrations.
Long Cycle Life Nanocellulose Polypyrrole Electrodes
Authors: Nyström Gustav , Olsson Henrik , Sjödin Martin , Carlsson Daniel O. , Mihranyan Albert , Nyholm Leif , Strømme Maria 
Published: April 2011

ABSTRACTA polypyrrole (PPy) nanocellulose composite was shown to cycle well over 3000 cycles in 2.0 M NaCl electrolyte when used as the active material for both electrodes in an energy storage device. SEM micrographs show a highly porous nature of the conductive paper material and electrochemical charge-discharge measurements, as well as external electrode potential monitoring, confirm the good cycling behavior of the material.
The Electrical Conduction at Early Stages of Cluster-Assembled Films Growth
Authors: Barborini Emanuele , Corbelli Gabriele , Milani Paolo 
Published: April 2011

ABSTRACTElectrical conduction in Fe, Pd, Nb, W and Mo cluster-assembled films was investigated in-situ, during their growth by supersonic cluster beam deposition. We observed for clusterassembled films resistivity values several orders of magnitude larger than corresponding bulk, as well as an increase of resistivity by increasing the film thickness, in contrast to the behaviour of atom-assembled metallic films. This suggests that nanoscale morphology arising by growth dynamics of cluster-assembled films, such as the minimal cluster-cluster interconnection and the evolution of surface roughness with thickness, may play a crucial role in the observed behaviour. Theoretical models based on non-isotropic 3D distributions of clusters into the film would help for a deeper understanding of the behaviour of cluster-assembled films compared to atomassembled ones. Benefits are expected in the technological field of devices performing electrical read-out on active nanostructured layers, as in the case of chemoresistive sensors.
Silicon nanowires solar cell
Authors: Xie Xiaobing , Zeng Xiangbo , Yao Wenjie , Yang Ping , Liu Shiyong , Peng Wenbo , Wang Chao , Zhang Xingwang , Zhu Hongliang , Wang Zhanguo 
Published: April 2011

ABSTRACTWe made an amorphous-silicon (a-Si) solar cell with a nanowire-array structure on stainless steel(SS) by plasma enhanced chemical vapor (PECVD) deposition. This nanowire structure has an n-type Si nanowire array in which a-Si intrinsic layer and p type layer are sequentially grown on the surface of the nanowire. The highest open-circuit voltage (Voc) and short-circuit current density (Jsc) for AM 1.5 illumination were 620 mV and 13.4 mA/cm2, respectively at a maximum power conversion efficiency of 3.57%.
Comprehensive light trapping study of next generation thin film solar cells
Authors: Zhou Zhou , Zhou Jian , Sun Xiaowei , Cheng Tim , Wang Shengqi , Yi Yasha 
Published: April 2011

ABSTRACTLight trapping is one of the key challenges for the next generation of thin film solar cells. In this work, we have identified the distinct light trapping effects for short and long wavelength solar spectrum ranges, by investigating lighting trapping structures on both sides of Si thin film solar cells. The sub-wavelength moth-eye-like photonic front surface and multi-layer grating photonic crystal reflector on the bottom surface are studied in detail via the Finite Difference Time Domain method for its solar energy absorption characteristics. Our study reveals the drastic difference in the light trapping effects within the solar spectrum wavelength. This work may provide guidance for efficiency enhancement of next generation thin film photovoltaic cells.
Binding of Dinuclear Ruthenium Complexes, SWNTs and Nanoparticles for Hybrid Nanocomposite Materials
Authors: Alston Jeffrey R. , Poler Jordan C. 
Published: April 2011

ABSTRACTIntegration of nanomaterials into composite systems is the next evolutionary step in nanoscale science. Until recently nanocomposites are formed by embedding nanomaterial components into matrices, through chemical bonding or with various wrapping agents. We seek to show that through directed self assembly nanomaterials can be coupled with photosensitizing ruthenium complexes while avoiding chemical augmentation and insulating effects from polymer, surfactant or DNA wrapping. We have synthesized dinuclear ruthenium complexes (dimers) possessing rigid conjugated π-electron systems that form a nanoscale pocket. The pocket is dimensionally suited to interact strongly with nanomaterials forming an architecture that could facilitate photon collection and charge transfer across the interaction. This study explores the binding interaction of our ruthenium dimers with SWNTs. The binding strength varies relative to the magnitude of formal charge which trends with DFT simulations that predict SWNT dimer interactions. SWNT surface saturation by ruthenium dimers can be observed using UV-visible spectroscopy and characterized with adsorption isotherms. We also explore a new technique to measure nanomaterial interactions, isothermal titration calorimetry (ITC). We show that ITC can be used to directly measure the binding enthalpy of nano material surface interactions in solution.
Electrospun Polythiophene Nanofibers and Their Applications for Organic Solar Cells
Authors: Chuangchote Surawut , Fujita Michiyasu , Sagawa Takashi , Yoshikawa Susumu 
Published: April 2011

ABSTRACTPoly(3-hexylthiophene) (P3HT) nanofibers were fabricated with an association of poly(vinyl pyrrolidone) (PVP) by electrospinning. A mixture of P3HT/PVP in a mixed solvent of chlorobenzene and methanol was electrospun to form composite fibers with 60 nm - 2 μm in diameter, followed by getting rid of PVP by selective extraction. After extraction, pure P3HT nanofibers were obtained as a spindle-like structure with wrinkled surface. The nanofibers obtained exhibit specific features of strong interchain contribution as investigated by UV-vis, fluorescence spectroscopic, X-ray diffraction (XRD), and photo-electron investigations. Bulk heterojunction P3HT:PCBM nanofibers with ~200 nm in diameters were also successfully fabricated by using the same technique. The preliminary results from the study of P3HT:PCBM nanofiber-based photovoltaic cells with conversion efficiency over 0.2% could be achieved.
Anisotropic Conducting Film (ACF) of Ag Nanoparticles as Transfer Polymer and Electrical Interface for Silicon Micro- and Nano- Pillars
Authors: Ombaba Matthew , Logeeswaran V. J , Islam M. Saif 
Published: April 2011

ABSTRACTWe report a novel application of Anisotropic Conductive Films (ACFs) technology to provide electrical contact and mechanical anchor between fracture transfer-printed (1-D) single crystal semiconductor micro- and nanopillars and a bottom metal. This fracture-transfer method enables highly crystalline micro- and nanopillars of different materials with diverse bandgaps and physical properties to be fabricated on appropriate mother substrates and transferred to form multilayered 3D stacks for multifunctional devices. The proposed protocol incorporates silver (Ag) nanoparticles into thermoplastic polymers exploitable in transfer-printed semiconductor devices and circuits with low contact resistance that is compatible with current IC processing methods. The vertical micropillars arrays are then embossed onto the polymer at its rubbery state by applying a vertical force leading to particle trapping between the bottom electrode and the micropillars. The polymer is then hardened while retaining the applied vertical force. By applying a lateral force on the mother substrate, the firmly cemented pillars are fractured off thereby allowing the mother substrate to be reused.
Plasmon Spectra at Wurtzite Aluminum Gallium Nitride / Silicon Carbide Heterojunctions
Authors: Praharaj Choudhury Jayant 
Published: April 2011

AbstractWe present theoretical calculations for electron plasmon spectra at wurtzite Aluminum Gallium Nitride/ Silicon Carbide heterojunctions. Spontaneous and piezoelectric polarizations in wurtzite semiconductors give rise to polarization discontinuities at interfaces and to bound interface sheet charges. These charges are of the order of 1013 electrons per cm2 and give rise to two dimensional electron or hole gases near heterojunctions. Electron-electron interactions in the two-dimensional electron gases give rise to collective plasmon excitations. We calculate the dielectric function in these electron gases under the well-known and widely studied random phase approximation. Our calculations are relevant to the determination of the plasmon spectra at wurtzite Aluminum Gallium Nitride / Silicon Carbide heterojunctions and are of potential interest for determining the limits of mobility in two-dimensional electron gases. They are also of interest for terahertz electronics applications.