Future prospect of remote Cat-CVD on the basis of the production, transportation and detection of H atoms

The future prospect of remote Cat-CVD, in which the decomposition and the deposition chambers are separated, is discussed on the basis of the absolute density measurements of H atoms. It is now well recognized that uniform deposition is possible on a large area without plasma damages by Cat-CVD. However, we may not overlook the demerits in Cat-CVD. One of the demerits is the poisoning of the catalyzer surfaces by the material gases, both temporary and permanent. One technique to overcome this problem is remote Cat-CVD. The question is how to separate the decomposition and deposition areas. If the separation is not enough, there should be back diffusion of the material gases, which will poison the catalyzers. If the separation is too tight, radicals may not effuse out from the decomposition chamber. These problems are discussed and it is shown that SiO₂ coating to reduce the radical recombination rates on walls is promising. The possibility of the polytetrafluoroethene coating by Cat-CVD is also discussed.     

Effects of polyglycerol esters of fatty acids and ethylene‐vinyl acetate co‐polymer on crystallization behavior of biodiesel

Biodiesel fuels (BDF) have many problems in the cold due to their crystallization properties. In particular, precipitation of large crystals of high‐melting fractions in BDF at low temperatures remarkably changes cold flow property of BDF and, thereby, it increases the values of cold filter plugging point. In this study, we evaluated polyglycerol esters of fatty acids (PGE) and ethylene‐vinyl acetate co‐polymer (EVA) as chemical additives to improve the cold flow property of palm oil‐based FAME (PFME). The results of solid fat content measurement indicate that the simultaneous addition of PGE and EVA showed synergistic effects on suppression of crystallization of PFME, however such effect was not observed when EVA was used alone. DSC thermograms indicated that the PGE additives not only decreased the crystallization temperature but also kinetically suppressed the crystal growth. Polarized light microscopy showed that the simultaneous addition of PGE and EVA led to the formation of considerably small and fine‐dispersed crystals of PFME. These results indicate that combined effects of PGE and EVA caused the formation of fine‐dispersed PFME crystals, which could improve the viscous properties of palm oil‐based BDF at relatively cold temperatures.     

Thermal stress prediction in divertor cooling finger using the local heat transfer distribution

An approach that combines computational fluid dynamics (CFD) and structural mechanics simulation is used for evaluating stresses in a divertor cooling finger. Local distributions of heat transfer coefficient (HTC) between the helium and inner surface of the thimble are used as a boundary condition for the structural mechanics analysis. Stresses calculated with a realistic non-homogeneous HTC distribution are compared with the results where averaged HTC values in three representative zones of inner thimble surface are used. The obtained maximum stresses are considerably higher in the case of realistic non-homogeneous HTC boundary condition. The highest thermal stresses in the tile–thimble assembly are obtained on the thimble inner surface, in the region where the highest thermal gradients due to jet cooling can be observed. The results also show that tetrahedral based finite element model underestimate the computed stresses, especially when a coarse mesh is used.     

Enhanced adhesion of osteoblastic cells on polystyrene films by independent control of surface topography and wettability

We independently controlled surface topography and wettability of polystyrene (PS) films by CF₄ and oxygen plasma treatments, respectively, to evaluate the adhesion and proliferation of human fetal osteoblastic (hFOB) cells on the films. Among the CF₄ plasma-treated PS films with the average surface roughness ranging from 0.9 to 70 nm, the highest adhesion of hFOB cells was observed on a PS film with roughness of ~ 11 nm. When this film was additionally treated by oxygen plasma to provide a hydrophilic surface with a contact angle less than 10°, the proliferation of bone-forming cell was further enhanced. Thus, the plasma-based independent modification of PS film into an optimum nanotexture for human osteoblast cells could be appplied to materials used in bone tissue engineering.     

Erbium electroluminescence in p-i-n amorphous hydrogenated silicon structures

A comparative analysis of λ=1.54 μm electroluminescent structures based on amorphous hydrogenated silicon is made. The possibility of obtaining room-temperature electroluminescence from forward-biased conventional p-i-n structures based on this material is demonstrated for the first time, which is of interest for the development of effective emitting structures with current pumping.     

Agronomic and economic evaluation of Tilemsi phosphate rock in different agroecological zones of Mali

Phosphorus deficiency is known as one of the major constraints to crop production in West Africa. Farmer-managed trials were conducted in three agroecological zones of Mali to evaluate the profitability of Tilemsi phosphate rock (TPR) in different crop-rotation systems in comparison with conventional water-soluble fertilizers. Marginal analyses were used to compare treatments tested. Results show that crop yields using TPR are comparable to those of recommended cotton- or cereal-complex imported fertilizers. The economic evaluation also clearly indicated that direct application of TPR is relatively profitable in comparison with recommended imported fertilizers and that good management enhances the profitability of fertilizers in general. This revised version was published online in August 2006 with corrections to the Cover Date.     

ASMD with duty cycle correction scheme for high-speed DRAM

An analogue synchronous mirror delay with duty cycle-correction scheme (ASMDCC), to improve the data transmission performance between DRAM and system, is proposed. The ASMDCC achieves duty cycle correction and clock synchronisation at once within two clock cycles, by using a half value current source. The simulation results show the duty cycle of the internal clock is stabilised with less than ±100 ps deviation from 50% for the wide duty cycle range     

Isolation of Salmonella sp. in sludge from septage treatment plant.

Waste stabilization ponds (WSP) are an often-used option to treat faecal sludges collected from on-site sanitation systems. Since agricultural use is one of the most attractive options for sludge disposal, specific guidelines on the hygienic sludge quality must be fulfilled, such as for viable helminth eggs and Salmonella sp. Although Salmonella isolation methods are well known for other types of samples, they are not suitable for faecal sludge. The reason can be attributed to the co-existence of a native bacterial sludge flora masking Salmonella development, especially if this bacteria is present at low concentrations. In order to select the best methodology for Salmonella recovery from septage sludge, different culture media were assayed at different incubation periods and temperatures. The proposed methodology for Salmonella recovery from sludge can be summarised as follows: (1) enrichment in Rappaport-Vassiliadis broth at 43 degrees C, 48 hours, and (2) isolation in XLD agar at 40 degrees C, 24 hours. Identification of suspected colonies by biochemical tests: TSI, LIA, urease and serological confirmation with Group O Antigen.     

Difference in the detection limits of flaws in the depths of multi-layered and continuous aluminum plates using low-frequency eddy current testing

We examined the difference in the detection limits of flaws in the depths of multi-layered and continuous aluminum plates using low-frequency eddy current testing. The detection limits were measured by using a magneto-resistive sensor. Comparing the frequency of an applied magnetic field, the detection limit at 50 Hz is deeper than that at 1 kHz. Comparing the sample structure, the detection limit in the multi-layered samples is deeper than that in the continuous samples. These results are likely due to the differences in the skin depth and conductivity of the sample.