Improving steam-reforming performance by nanopowdering CuCrO2

In this study, the delafossite type CuCrO₂ nanopowder was used as a precursor for preparing Cu-based catalyst for steam reforming of methanol (SRM). The efficiency of hydrogen generation was greatly improved by reducing the size of CuCrO₂ to nanoscale. The reduction temperature of Cu metal particles from CuCrO₂ decreased from 600 °C to 200 °C due to this size effect. Additionally, because of lowered activation energy, CuCrO₂ nanopowder could be reduced by methanol vapor. Thus the CuCrO₂ nanopowder, prepared by GNP method, had much higher SRM efficiency than bulk CuCrO₂ and the commercial SRM catalyst, even without H₂ activation process. The SEM images revealed that the powder retained a cotton candy-like porous structure after reduction treatment. The TEM images showed that the Cu particles were about 5 nm in diameter and well dispersed on Cr₂O₃ after the reduction of CuCrO₂ nanopowder at 500 °C. The catalyst was evaluated by the generation rate with steam reforming of methanol, and the peak hydrogen generation rate read as high as 2550 ml/min g-cat at 360 °C with hydrogen activation. CuCrO₂ nanopowder showed high catalytic activity even without reduction treatment, and hydrogen generation rate read as high as 1740 ml/min g-cat at 360 °C.     

Toward Cloud-Based Parking Facility Management System： A Preliminary Study

An e-tag used on the freeway is a kind of passive sensors composed of sensors and radio-frequency identification (RFID) tags. The principle of the electronic toll collection system is that the sensor emits radio waves touching the e-tag within a certain range, the e-tag will respond to the radio waves by induction, and the sensor will read and write information of the vehicles. Although the RFID technology is popularly used in campus management systems, there is no e-tag technology application used in a campus parking system. In this paper, we use the e-tag technology on a campus parking management system based on the cloud-based construction. By this, it helps to achieve automated and standardized management of the campus parking system, enhance management efficiency, reduce the residence time of the vehicles at the entrances and exits, and improve the efficiency of vehicles parked at the same time.     

Rhubarb inhibits hepatocellular carcinoma cell metastasis via GSK-3-β activation to enhance protein degradation and attenuate nuclear translocation of β-catenin

The aim of our study was to investigate the mechanisms by which rhubarb regulates β-catenin as well as metastasis of hepatocellular carcinomas. Our results revealed that rhubarb extract inhibited HA22T cell migration ability in wound healing, migration and invasion assays in a dose-dependent manner. Rhubarb also reduced β-catenin protein level, downregulated its downstream proteins, cyclin D, Tbx3 and c-Myc, and attenuated the expression of MMP9 and contactin-1 metastatic factors. Additionally, rhubarb inhibited β-catenin nuclear accumulation and induced its degradation via proteasome-mediated pathway. Furthermore, we found that rhubarb suppressed the p-ser⁹ GSK-3-β protein level to inactivate Wnt signalling and reduce β-catenin protein level. Taken together; we found that rhubarb blocked the metastatic process of HA22T hepatocellular carcinoma cells mediated through GSK-3-β activation, and enhancement of protein degradation as well as reduction of the nuclear accumulation of β-catenin.     

Stinky tofu as a rich source of bioavailable S-equol in Asian diets

The compound S-equol (4′,7-dihydroxy-isoflavandiol), a gut bacterial metabolite of isoflavone daidzein, benefits health, but only 20–60% of humans can produce equol after ingesting isoflavones, and it exists only in foods of animal origin in trace amounts. A recent study found a source of stinky tofu contained S-equol. As stinky tofu is a popular traditional fermented soy food in Taiwan, we analyzed S-equol contents of commercial samples, surveyed the intake frequency, and investigated the bioavailability of S-equol by monitoring urinary kinetics following ingestion. Our results showed 91% of the 138 stinky tofu dishes contained S-equol. The mean content per serving (average 198 g) was 2.3 ± 2.5 mg, the highest being 16.3 mg. Stinky tofu eaters on average ingested this food 3.3 times per month. S-equol from ingested stinky tofu appeared in urine within 1 h, reaching maximum excretion at 3.4 h, and 67% of the ingested S-equol was recovered in urine, indicating a rapid and high absorption. Our studies suggest stinky tofu can be a promising dietary source of S-equol for its high content and bioavailability. Further study on the S-equol producing bacteria in stinky tofu is merited for the development of other S-equol rich soy products.     

Properties of GaN-based light-emitting diodes on patterned sapphire substrate coated with silver nanoparticles prepared by mask-free chemical etching

This study reports on the use of a template that is made of silver nanoparticles (ANPs) that are dispersed on a patterned sapphire substrate (PSS) to improve the light output power of GaN-based light-emitting diodes (LEDs). The dipping of a sapphire substrate in hot H₂SO₄ solution generates white reaction products that are identified as a mixture of polycrystalline aluminum sulfates. These white reaction products can act as a natural etching mask in the preparation of an ANP-coated PSS (PSS-ANP) template. The optimal annealing temperature and time, surface morphology, and optical characteristics of the PSS-ANP template were investigated. The light output power of an LED that is bonded to the PSS-ANP template is approximately double than that of an LED that is not.     

Surface plasma resonant effect of gold nanoparticles on the photoelectrodes of dye-sensitized solar cells

In this study, we prepared different shapes of gold nanoparticles by seed-mediated growth method and applied them on the photoelectrodes of dye-sensitized solar cells (DSSCs) to study the surface plasma resonant (SPR) effect of gold nanoparticles on the photoelectrodes of dye-sensitized solar cells. The analyses of field emission scanning electron microscopy show that the average diameter of the spherical gold nanoparticles is 45 nm, the average length and width of the short gold nanorods were 55 and 22 nm, respectively, and the average length and width of the long gold nanorods were 55 and 14 nm, respectively. The aspect ratio of the short and long gold nanorods was about 2.5 and 4, respectively. The results of ultraviolet–visible absorption spectra show that the absorption wavelength is about 540 nm for spherical gold nanoparticles, and the absorption of the gold nanorods reveals two peaks. One is about 510 to 520 nm, and the other is about 670 and 710 nm for the short and long gold nanorods, respectively. The best conversion efficiency of the dye-sensitized solar cells with spherical gold nanoparticles and short and long gold nanorods added in is 6.77%, 7.08%, and 7.29%, respectively, and is higher than that of the cells without gold nanoparticles, which is 6.21%. This result indicates that the effect of gold nanoparticles on the photoelectrodes can increase the conductivity and reduce the recombination of charges in the photoelectrodes, resulting in the increase of conversion efficiency for DSSCs. In addition, the long gold nanorods have stronger SPR effect than the spherical gold nanoparticles and short gold nanorods at long wavelength. This may be the reason for the higher conversion efficiency of DSSCs with long gold nanorods than those of the cells with spherical gold nanoparticles and short gold nanorods.     

Secure Handover Authentication Protocol Based on Bilinear Pairings

Handover authentication protocol enables a mobile node to switch from one base station to another without loss or interruption of service when the node exits the transmission area of his or her current base station. This paper proposes a secure prime-order handover authentication protocol based on bilinear pairings. The proposed protocol adapts the concept of pseudonyms to provide user anonymity and user unlinkability. It withstands well-known security threats and achieves mutual authentication, user unlinkability. A batch signature verification mechanism to verify a mass of signatures is presented in our scheme. We also prove that our scheme is secure under random oracle.     

Improvement of the Nanoparticle Charging Efficiency of a Single-Wire Corona Unipolar Charger by Using Radial Sheath Airflow: Numerical Study

A single-wire corona unipolar charger with radial sheath air was proposed to enhance the nanoparticle charging efficiency. The charger consists of an insulated Teflon tube (inner diameter = 6.35 mm) with a 6 mm-long grounded porous metal tube placed at its center from which radial sheath air is introduced, and a discharge gold wire of 50 μm in the outer diameter and 6 mm in the effective length. The performance of the charger was evaluated and optimized numerically. The effect of the position of the sheath air opening on reducing charged particle loss was found to be important and two designs were studied. In design 1, both ends of the 6 mm wide sheath air opening are aligned with the ends of the 6 mm-long discharge wire, while in design 2 the sheath air opening is shifted 2 mm toward the left of the leading edge of the wire. At the same operating condition, design 2 was found to have less electrostatic loss than design 1 because of its smaller deposition region for charged particles. Compared to two unipolar chargers with the highest extrinsic charging efficiency for particles smaller than 10 nm in diameter, design 2 operated at the applied voltage of +3.5 kV, aerosol flow rate of 0.5 L/min, and sheath airflow rate of 0.7 L/min has a comparable extrinsic charging efficiency of 17.2%–70.5% based on particle number for particles ranging from 2.5 to 10 nm in diameter.

Copyright 2013 American Association for Aerosol Research     

A Study of Rheological Behavior and Compatibility of NR/BR Blends

In this study, we research the Mooney viscosity, curing rates, and processibility of natural rubber (NR) and polybutadiene rubber (BR) blends at different blending ratios. The changing values are measured during vulcanization processing and were tested by Mooney viscometer, Monsanto viscometer, etc. The results of scanning electron microscope (SEM) and dynamic mechanical analysis (DMA) experiments are used to explore the surface morphologies and molecular mobility of NR/BR blends.

The experimental results indicate that Mooney viscosity tends to decrease with increasing NR content of NR/BR blends, and this results in superior processibility of NR/BR blends with increasing NR content. NR/BR blends' curing rate improved with increasing NR content. The DMA experimental results show that the temperature is suitable to produce a character peak (T_αn) in molecular motions of NR/BR blends. There tends to a lower temperature range with decreasing NR content of NR/BR blends. In addition, T_αb would move to a lower temperature with decreasing BR content of NR/BR blends.     

Tribological Performance of Oil-Based Lubricants with Carbon-Fe Nanocapsules Additive

The present study investigates the tribological properties of carbon-Fe nanocapsules (CFNCs) under high contact loads. Block-on-ring wear tests are performed using mineral oil lubricants containing CFNC particles with concentrations ranging from 0.01 to 0.1 wt%. In addition, high-resolution electron transmission microscopy (HR-TEM) and scanning electron microscopy (SEM) analysis were conducted on the test samples. The results show that for a contact load of 650 N, a CFNC concentration of 0.07 wt% and a sliding velocity of 1.65 m/s enhance the surface permeability, fill-up properties, and microbearing lubrication mechanism and promote effective reduction in the wear at the surface contact interface.