Parametric Optimization of Complementary Split-Ring Resonator Dimensions for Planar Antenna Size Miniaturization

Wireless Personal Communications -     

Impact of Firefighting Sprays on the Fire Performance of Structural Steel Members

Fire Technology - The feasibility of coupled computational fluid dynamics (CFD) and finite element (FE) simulations to aid the planning of fire intervention tactics and the effectiveness of...     

Investigations of Surface Properties of SAW Fluxes Using CaO-SiO2-TiO2 & Al2O3-CaO-SiO2 Ternary Phase Systems

Silicon - In the present paper, investigation on wettability and contact angle measurement of twenty-one SAW fluxes for CaO-SiO2-TiO2 & Al2O3-CaO-SiO2 welding flux system at a temperature...     

Nickel/Cobalt nanoparticles for electrochemical production of hydrogen

The electrolytic production of hydrogen (POH) from alkaline water electrolysis is at the forefront of technology for alternative energy sources of the future. The present work evaluates the improvement of electro-catalytic activity (ECA) on Ni electrodes for the POH by electrodeposition of cobalt (Co). Tests were conducted in alkaline solution and the ECA of Ni and Ni–Co electrodes for the POH were compared using alternative and direct current techniques. Tafel polarization tests exemplified a significant improvement in the ECA of the bimetallic electrode (Ni–Co) compared with the Ni-electrode. Besides, the bimetallic electrode required less input overpotential energy (η) for the given POH rate under constant current density. Electrochemical impedance spectroscopy (EIS) revealed a significant increase in the number of electrochemical active sites and changed the surface morphology following the electrodeposition of Co over Ni electrodes.     

Cognitive Mapping and Planning for Visual Navigation

International Journal of Computer Vision - We introduce a neural architecture for navigation in novel environments. Our proposed architecture learns to map from first-person views and plans a...     

Development of docetaxel nanocapsules for improving in vitro cytotoxicity and cellular uptake in MCF-7 cells

The aim of this study was to fabricate docetaxel loaded nanocapsules (DTX-NCs) with a high payload using Layer-by-Layer (LbL) technique by successive coating with alternate layers of oppositely charged polyelectrolytes. Developed nanocapsules (NCs) were characterized in terms of morphology, particle size distribution, zeta potential (ζ-potential), entrapment efficiency and in vitro release. The morphological characteristics of the NCs were assessed using transmission electron microscopy (TEM) that revealed coating of polyelectrolytes around the surface of particles. The developed NCs successfully attained a submicron particle size while the ζ-potential of optimized NCs alternated between (+) 34.64?±?1.5 mV to (?) 33.25?±?2.1 mV with each coating step. The non-hemolytic potential of the NCs indicated the suitability of the developed formulation for intravenous administration. A comparative study indicated that the cytotoxicity of positively charged NCs (F4) was significant higher (p?in vitro on MCF-7 cells. Furthermore, cell uptake studies evidenced a higher uptake of positive NCs (≥1.2 fold) in comparison to negative NCs. In conclusion, formulated NCs are an ideal vehicle for passive targeting of drugs to tumor cells that may result in improved efficacy and reduced toxicity of encapsulated drug moiety.     

Al-4.5Cu-2Mg合金应力-应变定位及分布的有限元分析（英文）

通过有限元方法分析不同加工路线和条件对Al-4.5Cu-2Mg合金微观形变行为的影响。合金采用4种不同的加工技术和条件制备,分别为有或无细化剂的常规重力铸造、流变铸造和SIMA工艺。以合金的光学显微结构作为代表性体积元(RVEs),采用两种不同的边界条件模拟合金在单轴载荷作用下的变形行为,最后将模拟的应力-应变行为与实验结果进行比较。结果表明,微观结构形态对应力和应变分布及承载能力具有显著影响,共晶相比α(Al)相能承受更高的载荷,具有较薄且均匀分布的共晶网络结构的球状α(Al)相能提供更好的应力和应变分布。因此,SIMA加工合金比其他技术加工合金拥有更好的应力和应变分布。最后,将该合金的模拟屈服强度与实验进行验证,结果具有较好的一致性。     

HA/β-TCP plasma sprayed coatings on Ti substrate for biomedical applications

The present work focuses on the fabrication of βTCP (β-tricalcium phosphate) and HA/βTCP (hydroxyapatite/β-tricalcium phosphate) composite coatings by plasma spraying. The starting powders were produced via solid-state method using 2 wt% MgO to stabilize βTCP phase. The synthesized powders were preliminarily granulated to be used by the plasma spray process. Coatings obtained on titanium substrates are uniform and well adherent but due to the high temperature and cooling rate typical for plasma spraying process, βTCP phase is almost totally transformed into the α allotrope. Thermal treatment at 800 °C allows the reconversion of the phase αTCP→ βTCP. It is therefore possible to produce coatings with tuneable dissolution properties by selecting the proper initial powder mixture and the specific thermal treatment.     

Effect of Ti Addition and Microstructural Evolution on Toughening and Strengthening Behavior of as Cast or Annealed Nb–Si–Mo Based Hypoeutectic and Hypereutectic Alloys

Room temperature fracture toughness along with compressive deformation behavior at both room and high temperatures (900 °C, 1000 °C and 1100 °C) has been evaluated for ternary or quaternary hypoeutectic (Nb–12Si–5Mo and Nb–12Si–5Mo–20Ti) and hypereutectic (Nb–19Si–5Mo and Nb–19Si–5Mo–20Ti) Nb-silicide based intermetallic alloys to examine the effects of composition, microstructure, and annealing (100 hours at 1500 °C). On Ti-addition and annealing, the fracture toughness has increased by up to ~ 75 and ~ 63 pct, respectively with ~ 14 MPa√m being recorded for the annealed Nb–12Si–5Mo–20Ti alloy. Toughening is ascribed to formation of non-lamellar eutectic with coarse Nb_ss, which contributes to crack path tortuosity by bridging, arrest, branching and deflection of cracks. The room temperature compressive strengths are found as ~ 2200 to 2400 MPa for as-cast alloys, and ~ 1700 to 2000 MPa after annealing with the strength reduction being higher for the hypoeutectic compositions due to larger Nb_ss content. Further, the compressive ductility has varied from 5.7 to 6.5 pct. The fracture surfaces obtained from room temperature compression tests have revealed evidence of brittle failure with cleavage facets and river patterns in Nb_ss along with its decohesion at non-lamellar eutectic. The compressive yield stress decreases with increase in test temperature, with the hypoeutectic alloys exhibiting higher strength retention indicating the predominant role of solid solution strengthening of Nb_ss. The flow curves obtained from high temperature compression tests show initial work hardening, followed by a steady state regime indicating dynamic recovery involving the formation of low angle grain boundaries in the Nb_ss, as confirmed by electron backscattered diffraction of the annealed Nb–12Si–5Mo alloy compression tested at 1100 °C.