Synthesis of Fe3O4 Nanowire Arrays Via Precipitation in Templates and Microwave Hydrothermal Process

Template growth of Fe₃O₄ nanowire arrays via precipitation and subsequent microwave hydrothermal process was investigated. Anodic aluminum oxide and polycarbonate templates were immersed in a ferrous chloride and ferric chloride mixture and the precipitation of Fe₃O₄ took placed by adjusting the solution to pH>9. A microwave hydrothermal process was subsequently performed at 150°C for 30 min in order to further enhance the crystallinity of the Fe₃O₄ nanowires. The length of the nanowires is about 5–20 μm and the diameter is about 220 nm, with perfect surface finishing. The nanowires were polycrystalline cubic spinel structures and composed of nanometer-sized particles, as characterized by X-ray diffraction, field emission scanning electron microscopy, and transmission electron microscopy. Magnetic properties in parallel and perpendicular direction were measured using a vibrating sample magnetometer, where the magnetization in the perpendicular direction of the nanowires is higher than that of the parallel direction. Microwave hydrothermal treatment improved the crystallinity and morphology of Fe₃O₄ nanowires and resulted in a much better magnetization than that without microwave hydrothermal treatment.     

Hydrothermal catalytic production of fuels and chemicals from aquatic biomass

One of the promising avenues for biomass processing is the use of water as a reaction medium for wet or aquatic biomass. This review focuses on the hydrothermal catalytic production of fuels and chemicals from aquatic biomass. Two different regimes for conversion of aquatic biomass in hydrothermal conditions are discussed in detail. The first is hydrothermal liquefaction, and the second is hydrothermal gasification. The goals of these processes are to produce liquid‐fuel‐range hydrocarbons and methane or hydrogen, respectively. The catalytic upgrading of biocrude resulting from noncatalytic liquefaction and the stability and degradation of catalysts in high temperature water are also discussed. The review concludes with a brief discussion of the outlook for and opportunities within the field of hydrothermal catalytic valorization of biomass. Copyright © 2012 Society of Chemical Industry     

Diffusion Deposition on Model Fibrous Filters with Intermediate Porosity

Theoretical and experimental studies of the diffusional deposition of aerosols on model niters of intermediate packing density are reported. At low Reynolds number (Re« 1) and intermediate porosity (0.01 < α < 0.4), the Kuwabara flow field is applicable for parallel staggered model filters, and the diffusional deposition efficiency can be expressed as A = 2.92 n [(l-a)/k]^1/3 Pe ^?2/3. By applying a correction factor based on the ratio of pressure drops to this equation, the deposition efficiency for a fan model filter is n = A Pe ^?2/3, where A has a value of 2.4–2.6 for α = 0.05–0.4. The efficiency increases with the fiber solidity, α for the parallel staggered filter, but is essentially independent of a for the fan model filter. Experimental results of diffusional deposition of ultrafine aerosols on wire screens which is used as a fan model filter has been performed. Summary data on screens and the fan model filter reported in the literature show that the single fiber efficiency is independent of the solid volume fraction and can be expressed as n = 2.7 Pe ^?2/3 where Pe is the Peclet number (over the range of 0.02 < a < 0.35). The small difference between the experimental data and theory can be explained by the approximate nature of the flow field used in the theory.     

Performance Comparison of Rectangular and Air-Foil Shapes Offset Strip Flow Paths Micro-Heat Exchangers

This study designed and tested eight micro-heat exchangers with rectangle-, air-foil-, and shuttle-type strips for use in the liquid cooling system. The effects of strip length, strip type, and strip arrangement were considered for heat transfer performance comparison. The test results show that the heat exchangers with shorter strip length and narrower strip space provide better heat transfer performance. The short air-foil strips heat exchanger with 1.0 mm strip length performed the lowest thermal resistance among all types of heat exchangers. Because of its narrow flow paths, the performance of the overlapped shuttle strip heat exchanger is better than that of the offset shuttle, long air-foil, and rectangle strip heat exchangers. However, the space between strips is limited by the fabrication techniques and is difficult to be made narrower by the method of chemical etching.     

The triterpenoids of Ganoderma tsugae prevent stress‐induced myocardial injury in mice

Ganoderma mushrooms (Lingzhi in Chinese) have well‐documented health benefits. Ganoderma tsugae (G. tsugae), one of the ganoderma species, has been commercially cultivated as a dietary supplement. Because G. tsugae has high antioxidant activity and because oxidative stress is often associated with cardiac injury, we hypothesized that G. tsugae protects against cardiac injury by alleviating oxidative stress. We tested the hypothesis using a work‐overload‐induced myocardial injury model created by challenging mice with isoproterenol (ISO). Remarkably, oral G. tsugae protected the mice from ISO‐induced myocardial injury. Moreover, the triterpenoid fraction of G. tsugae, composed of a mixture of nine structurally related ganoderic acids (GAs), provided cardioprotection by inhibiting the ISO‐induced expression of Fas/Fas ligand, oxidative stress, and apoptosis. The antioxidant activity of GAs was tested in cultured cardio‐myoblast H9c2 cells against the insult of H₂O₂. GAs dissipated the cellular reactive oxygen species imposed by H₂O₂ and prevented cell death. Our findings uncovered the cardioprotective activity of G. tsugae and identified GAs as the bioactive components against cardiac insults.     

The p38 and NFκB signaling protein activation involved in glycitein protective effects on isoproterenol-treated H9c2 cardiomyoblast cells

Heart disease (HD) is greatly associated with gender and clinical evidence shows that increased serum norepinephrine levels are found in patients with HD. This study investigates the cardio-protective effect of glycitein, a selective estrogen receptor modulator (SERM) from soy bean extract, on H9c2 cardiomyoblast cells treated with isoproterenol (ISO, a norepinephrine analog). The image data and results from western blotting showed that ISO treatment was capable of inducing cellular apoptosis, especially the mitochondrial dependent pathway. Glycitein treatment could suppress mitochondrial pro-apoptotic proteins expression including caspase-9 and caspase-3 in H9c2 treated with ISO. In contrast, several survival proteins were expressed in H9c2 cells treated with glycitein, such as phosphor (p)-Akt, p-Bad and Akt. We confirmed that the protective role of glycitein was partially mediated through the expression of p-38 and NFκB proteins by adding several pathway inhibitors.     

Experimental demonstration of CW light injection effect in upstream traffic TDM-PON

High capacity time-division-multiplexed passive optical network (TDM-PON) is an emerging fiber access network that deploys optical access lines between a carrier’s central office (CO) and a customer sites. In this investigation, we demonstrate and analyze the continuous wave (CW) upstream effect in TDM-PONs. Besides, we also propose and design a protection apparatus in each optical network unit (ONU) to avoid a CW upstream traffic in TDM-PONs due to sudden external environment change or ONU failure. When an upstream CW injection occurs in TDM access network, the protection scheme can stop the CW effect within a few ms to maintain the entire data traffic.     

Room-Temperature Preparation of High-Transparency Low-Resistivity ITO Films by Ion Beam Sputtering

Low-temperature preparation of transparent conducting electrodes is essential for flexible optoelectronic devices. Tin-doped In₂O₃ films with high transparency and low electrical resistance were prepared at room temperature using a radiofrequency ion beam sputtering system. Specimens with a low sheet resistivity of 10⁻⁴ Ω cm and a high visible-light transmittance of 85% to 90% were obtained. Hall measurements were used to determine mobility and carrier concentration, and the effects on resistivity are discussed.     

Interblock memory for turbo coding

We investigate a binary code, which is implemented by serially concatenating a multiplexer, a multilevel delay processor, and a signal mapper to a binary turbo encoder. To achieve improved convergence behavior, we modify the binary code by passing only a fraction of the bits in the turbo code through the multilevel delay processor and the signal mapper. Two decoding methods are discussed and their performances are evaluated.     

Passive cathodic water/air management device for micro-direct methanol fuel cells

A high efficient passive water/air management device (WAMD) is proposed and successfully demonstrated in this paper. The apparatus consists of cornered micro-channels and air-breathing windows with hydrophobicity arrangement to regulate liquids and gases to flow on their predetermined pathways. A high performance water/air separation with water removal rate of about 5.1 μl s⁻¹ cm⁻² is demonstrated. The performance of the proposed WAMD is sufficient to manage a cathode-generated water flux of 0.26 μl s⁻¹ cm⁻² in the micro-direct methanol fuel cells (μDMFCs) which are operated at 100 mW cm⁻² or 400 mA cm⁻². Furthermore, the condensed vapors can also be collected and recirculated with the existing micro-channels which act as a passive water recycling system for μDMFCs. The durability testing shows that the fuel cells equipped with WAMD exhibit improved stability and higher current density.