SrCe0.7Zr0.2Eu0.1O3-based hydrogen transport water gas shift reactor

Proton-transport-membrane water gas shift (WGS) reactors, based on thin dense SrCe_0.7Zr_0.2Eu_0.1O_3−δ membranes on tubular Ni–SrCe_0.8Zr_0.2O_3−δ supports, were developed to increase H₂ yields relative to thermodynamic limitations. Pure H₂ permeate, total H₂ production, and reactor side CO conversion and H₂/CO effluent ratio were measured as a function of temperature, flow rate, CO concentration and H₂O/CO feed ratios. CO conversion, total H₂ production and yield, and the H₂/CO in the reactor side effluent increased with increasing temperature and H₂O/CO feed ratios. CO conversions of 84% and 90% were achieved at 900 °C with H₂O/CO feed ratios of 1/1 and 2/1, respectively. These respective 77% and 44% increases in CO conversion compared to feed gas condition thermodynamics resulted in 73% and 42% increases in H₂ production. Permeated H₂ and total H₂ production increased with increasing flow rate and CO concentration. Finally, membrane stability under WGS conditions was significantly improved by Zr substitution.     

A review on conventional technologies and emerging process intensification (PI) methods for biodiesel production

Biodiesel is commonly produced from lipid feedstock, animal fats and waste cooking oil by transesterification reaction. Considering the depletion of fossil fuel, biodiesel is gaining more attention as a renewable and environmental friendly fuel. The rapid growth of biodiesel industry thereafter has raised concerns to many existing commercial biodiesel enterprises. The major issues like feedstock flexibility, yield productivity and environmental impact are always the challenges to the continuous growth of conventional biodiesel processing technology. The processing of biodiesel is greatly hinged on the rich scientific background and technology development for better process advancement. The present paper reviews various concerns raised from the commercial biodiesel processing technology. It also addresses some innovative process intensification (PI) technologies, which likely bring appropriate technological improvement for biodiesel production.     

High temperature corrosion behavior of Ni-based alloys

The high temperature corrosion behavior of N07263, N06600, and N06625 in LiCl-Li₂O molten salt was investigated at temperatures ranging from 650 to 850 °C in a glove box. The high temperature corrosion behavior was observed using measurements of the oxide morphology and thickness, the extent of internal corrosion, and the compositional changes in the scale and in the substrate. Corrosion tests were performed, and these demonstrated that the main corrosion products were Fe(Ni,Co)₃, FeNi₃, and LiCrO₂. The internal corrosion of N07263 was localized, while that of N06600 maintained intergranular corrosion throughout the test temperature range. N06625 exhibited uniform intergranular corrosion behaviors at low and high temperatures. N07263 exhibited superior corrosion resistance, as evidenced by its corrosion layer which was more continuous, dense, and adherent when compared with those of N06600 and N06625.     

Hydrogen effects on deep level defects in proton implanted Cu(In,Ga)Se2 based thin films

Hydrogen effects on deep level defects and a defect generation in proton implanted Cu(In,Ga)Se₂ (CIGS) based thin films for solar cell were investigated. CIGS films with a thickness of 3 μm were grown on a soda-lime glass substrate by a co-evaporation method, and then were implanted with protons. To study deep level defects in the proton implanted CIGS films, deep level transient spectroscopy measurements on the CIGS-based solar cells were carried out, these measurements found 6 traps (including 3 hole traps and 3 electron traps). In the proton implanted CIGS films, the deep level defects, which are attributed to the recombination centers of the CIGS solar cell, were significantly reduced in intensity, while a deep level defect was generated around 0.28 eV above the valence band maximum. Therefore, we suggest that most deep level defects in CIGS films can be controlled by hydrogen effects.     

Study on the ITO work function and hole injection barrier at the interface of ITO/a-Si:H(p) in amorphous/crystalline silicon heterojunction solar cells

For this study we focused on the front contact barrier height of HIT (ITO/a-Si:H(p)/a-Si:H(i)/c-Si(n)) solar cell. The ITO films with low resistivity of 1.425 × 10^?4 Ω cm were deposited by pulsed DC magnetron sputtering as a function of substrate temperature (T_s). There were improvement in Φ_ITO from 4.15 to 4.30 eV and delta hole injection barrier from 0 to 0.129 eV for the HIT solar cell. The results show that the high values of Φ_ITO and the delta hole injection barrier at the front interface of ITO/p-layer lead to an increase of open circuit voltage (V_oc), fill factor (FF) and efficiency (η). The performance of HIT device was improved with the increase of T_s and the best photo voltage parameters of the device were found to be V_oc = 635 mV, FF = 0.737 and η = 14.33% for T_s = 200 °C.     

Low-resistivity Cu film electrodeposited with 3-N,N-dimethylaminodithiocarbamoyl-1-propanesulfonate for the application to the interconnection of electronic devices

In this study, we analyzed the properties of Cu films electrodeposited with 3-N,N-dimethylaminodithiocarbamoyl-1-propanesulfonate (DPS) as an organic additive in damascene Cu electrodeposition, in comparison with bis(sulfopropyl) disulfide (SPS). It was observed that the resistivity of Cu film electrodeposited with DPS was lower than that with SPS. Spectroscopic analyses showed that the impurity level and crystallinity of Cu films are almost the same, but the difference was found in the film roughness. Low roughness of Cu film electrodeposited with DPS led to the low resistivity, and it was speculated that the low roughness is related to the strong adsorption through the nitrogen atom in the DPS molecule.     

Dose response of commercially available optically stimulated luminescent detector, Al2O3:C for megavoltage photons and electrons

This study examined the dose response of an optically stimulated luminescence dosemeter (OSLD) to megavoltage photon and electron beams. A nanoDot? dosemeter was used to measure the dose response of the OSLD. Photons of 6-15 MV and electrons of 9-20 MeV were delivered by a Varian 21iX machine (Varian Medical System, Inc. Milpitas, CA, USA). The energy dependency was <1 %. For the 6-MV photons, the dose was linear until 200 cGy. The superficial dose measurements revealed photon irradiation to have an angular dependency. The nanoDot? dosemeter has potential use as an in vivo dosimetric tool that is independent of the energy, has dose linearity and a rapid response compared with normal in vivo dosimetric tools, such as thermoluminescence detectors. However, the OSLD must be treated very carefully due to the high angular dependency of the photon beam.