Modified poly(caprolactone trifumarate) with embedded gelatin microparticles as a functional scaffold for bone tissue engineering

Bone tissue engineering offers high hopes in reconstructing bone defects that result from trauma, infection, tumors, and other conditions. However, there remains a need for novel scaffold materials that can effectively stimulate ossification with appropriate functional properties. Therefore, a novel injectable, biodegradable, and biocompatible scaffold made by incorporating modified poly(caprolactone trifumarate) (PCLTF) with embedded gelatin microparticles (GMPs) as porogen is developed. Specifically, in vitro and in vivo tests were carried out. For the latter, to determine the osteogenic ability of PCLTF‐GMPs scaffolds, and to characterize bone‐formation, these scaffolds were implanted into critical‐sized defects of New Zealand white rabbit craniums. Field Emission Scanning Electron Microscope (FESEM) demonstrated cells of varying shapes attached to the scaffold surface in vitro. The PCLTF‐GMPs demonstrated improved biocompatibility in vivo. Polyfluorochrome tracers detected bone growth occurring in the PCLTF‐GMPs filled defects. By incorporating PCLTF with GMPs, we have fabricated a promising self‐crosslinkable biocompatible and osteoconducive scaffold for bone tissue engineering. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43711.     

Performance of FCCI barrier foils for U-Zr-X metallic fuel

Diffusion couple tests of U-Zr or U-Zr-Ce alloys vs. ferritic martensitic steels such as HT9 or T91 were carried out in order to evaluate the performance of the diffusion barrier candidates. Elemental metal foils of Zr, Nb, Ti, Mo, Ta, V and Cr were very effective in inhibiting interdiffusion between these fuels and steels. Eutectic melting between the fuels and steels was not observed in any of the diffusion couples using these diffusion barrier foils at annealing temperatures up to 800 °C. Among the metallic foils evaluated in this study, V and Cr exhibited the most promising performances as a diffusion barrier material for eliminating the fuel cladding chemical interaction problem. However, Zr, Nb and Ti showed an active interaction with the fuel mainly due to the large U solubility.     

Steam plasma reforming of biogas by non-thermal pulsed discharge

The purpose of this study was to develop technology that can convert biogas to synthesis gas (SynGas), a low emission substituted energy, using a non-thermal pulsed plasma method. To investigate the characteristics of the SynGas production from simulated biogas, the reforming characteristics were studied about the variations of pulse frequency, biogas component ratio (C₃H₈/CO₂), vapor flow ratio (H₂O/TFR), biogas velocity and pulse power. A maximum conversion rate of 49.1% was achieved for the biogas when the above parameters were 500 Hz, 1.5, 0.52, 0.32 m/s and 657 W, respectively. Under the above-mentioned reference conditions, the dry basis concentrations of the SynGas were, H₂ 64.5%, CH₄ 8.1%, C₂H₂ 6.7%, C₃H₆ 4.9%, CO 0.8% and C₂H₄ 0.4%. The ratio of hydrogen to the other intermediates in the SynGas (H₂/TTMs) was 3.1.     

Performance of an adaptive successive serial-parallel CDMAcancellation scheme in flat Rayleigh fading channels

The performance of a successive concatenated cancellation scheme for code-division multiple-access (CDMA) uplink transmission in cellular mobile radio is presented. Both serial and parallel cancellation stages are employed. The serial cancellation stage is first used to obtain initial data estimates followed by the parallel cancellation stages to enhance the accuracy of the estimates. The performance of this scheme is evaluated via analysis and simulation. In our analysis, we develop a model to consider the impact of wrongly estimating the phase and amplitude of the channel impulse response on the successive concatenated cancellation scheme. Analysis and simulation results in flat Rayleigh fading asynchronous channels with both perfect and nonperfect channel estimation and with perfect ranking confirms the accuracy of our analytical model as well as the significant improvement in performance compared to the conventional single-user matched filter (MF) detection and the stand-alone parallel cancellation schemes. Analytical results also show that the concatenated scheme has the potential to reach the single-user performance bound for a wide range of user base size, up to K=120 users, with a processing gain of 127 using one serial and three parallel cancellation stages. Finally, we propose a method whereby the receiver adapts with the number of users in order to retain the bit error ratio (BER) performance while decreasing the processing delay     

Effect of Oxidation Time on Thermally Grown Oxide on GaN

Gallium oxide (Ga₂O₃) has been successfully grown on top of an n-type gallium nitride (GaN) substrate via thermal oxidation process which is performed in nitrous oxide ambient at 1000 °C. Effects of oxidation times on physical properties of the thermal oxide have been investigated using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, field-emission scanning electron microscopy (FESEM), and atomic force microscopy (AFM). XRD analysis discloses the presence of monoclinic β-Ga₂O₃ which is the most thermodynamically stable form of Ga₂O₃ on the GaN substrate after thermal oxidation. FTIR spectra shows a Ga-O vibration mode at the band around 620-660 cm^?1 for all the oxidized samples. Besides, FESEM and AFM results indicate that protrusions of grains are revealed on the surface after thermal oxidation. In addition, surface roughness of the oxide was also found to be increased with the increasing oxidation duration.     

Correction to: Enhanced critical current density of ex situ MgB2 via control of Mg assisted sintering

Journal of Materials Science: Materials in Electronics -     

Simple, low-cost technique for photolithographic self-aligned top metal contacts to nanowires and nanotubes

We propose a new simple, low-cost method for providing all-round metal contacts to one-dimensional structures such as carbon nanotubes and nanowires on a transparent substrate. The nanostructures are first positioned in place to bridge a electrode gap by dielectrophoresis. The electrode structure is then used as a self-aligned mask during the subsequent photolithography through illumination from the substrate backside. This is followed by metallization and lift-off. Our measurements on multi-walled carbon nanotubes thus contacted show reasonable yield and good electrical contacts for the process carried out on a glass slide as the substrate.     

Formation of intermetallic compound at interface between rare earth elements and ferritic-martensitic steel by fuel cladding chemical interaction

The intermetallic compounds formation at interface between rare earth elements and clad material were investigated to demonstrate the effects of rare earth elements on fuel-cladding chemical interaction(FCCI)behavior.Mischmetal(70Ce-30La)and Nd were prepared as rare earth elements.Diffusion couple testing was performed on the rare earth elements and cladding(9Cr2W steel)near the operation temperature of(sodium-cooled fast reactor)SFR fuel.The performance of a diffusion barrier consisting of Zr and V metallic foil against the rare earth elements was also evaluated.Our results showed that Ce and Nd in the rare earth elements and Fe in the clad material interdiffused and reacted to form intermetallic species according to the parabolic rate law,describing the migration of the rare earth element.The diffusion of Fe limited the reaction progress such that the entire process was governed by the cubic rate law.Rare earth materials could be used as a surrogate for high burnup metallic fuels,and the performance of the barrier material was demonstrated to be effective.     

Reaction between a rare earth element and 9Cr-2W steel

We analyzed the reaction between a rare earth element and ferritic-martensitic stainless steel in order to evaluate the role of the rare earth element in the fuel cladding chemical interaction (FCCI). A diffusion couple test between Misch metal (70Ce-30La) and 9Cr-2W (Gr.92) steel at both 660 °C and 800 °C was conducted, and a microstructural analysis was carried out. The result showed that Fe in the Gr.92 material and Ce in the Misch metal mainly diffused and reacted to form intermetallic compounds, namely Fe₂Ce and Fe₁₇Ce phases, above 660 °C, whereas La hardly diffused or reacted in the Gr.92 material. In the specimen tested at 660 °C, the Fe diffused outside of the clad interface so that Cr-rich precipitated beneath the clad interface. In the specimen tested at 800 °C, a local reaction caused by the eutectic transformation of the (Fe,Cr)₁₇Ce phase resulted in a local penetration across the clad.     

A New Material for High‐Temperature Lead‐Free Actuators

Unimorph cantilevers are made from 0.5BaTiO₃‐0.5Sm₂O₃ (BTO‐SmO) self‐assembled vertical heteroepitaxial nanocomposite thin films, grown by PLD on (001) SrTiO₃ single crystal substrates. The films remain piezoelectric up to at least 250 °C without losing any actuation. The longitudinal piezoelectric coefficient, d₃₃, is ≈45 to 50 pm V^?1 measured from room temperature to 250 °C. The transverse piezoelectric coefficient, d₃₁, a key parameter of actuator performance, exceeds PZT (Pb_1–xZr_xTiO₃) films at >200 pm V^?1. Since the d₃₁ coefficient was found to be positive, this opens up exciting new applications opportunities. The possible reasons for d₃₁ > 0 are discussed in the light of 3D strain control in the nanocomposites.