Investigation on wear and rolling contact fatigue of wheel-rail materials under various wheel/rail hardness ratio and creepage conditions

The wear and rolling contact fatigue of wheel-rail materials were investigated through varying wheel/rail hardness ratios (Hw/Hr) and creepages. The results indicated that with the Hw/Hr increasing from 0.927 to 1.218, the wheel wear rate reduced significantly in the case of Hw/Hr = 1.218, the rail wear rate showed an increasing trend. Both the wheel and rail wear rates increased as the creepage enlarged. The synergistic results of Hw/Hr and creepage caused a transition of the wear and damage mechanisms on the wheel-rail steels. Besides, the fatigue damage of ER7 and CL60 wheel materials was dominated by slender multi-layer cracks, while the fatigue cracks were short and contained lots of interlayer broken materials on C-class wheel steel

Synthesis of calcium carbonate capsules in water-in-oil-in-water double emulsions

10.1557/jmr.2008.0017Journal of Materials Research231140-149JMRE

Electron fluence correction factors for conversion of dose in plastic to dose in water

In radiation dosimetry protocols, plastic is allowed as a phantom material for the determination of absorbed dose to water in electron beams. The electron fluence correction factor is needed in conversion of dose measured in plastic to dose in water. There are large discrepancies among recommended values as well as measured values of electron fluence correction factors when polystyrene is used as a phantom material. Using the Monte Carlo technique, we have calculated electron fluence correction factors for incident clinical beam energies between 5 and 50 MeV as a function of depth for clear polystyrene, white polystyrene and PMMA phantom materials and compared the results with those recommended in protocols as well as experimental rallies from published data. In the Monte Carlo calculations, clinical beams are simulated using the EGS4 user code BEAM for a variety of medical accelerators. The study shows that our calculated fluence correction factor, φ(p)/(w), is a function of depth and incident beam energy Ē0 with little dependence on other aspects of beam quality. However the φ(p)/(w) values at d(max) are indirectly influenced by the beam quality since they vary with depth and d(max) also varies with the beam quality. Calculated φ(p)/(w) values at d(max) are in a range of 1.005-1.045 for a clear polystyrene phantom, 1.005-1.038 for a white polystyrene phantom and 0.996- 1.016 for a PMMA phantom. Our values of φ(p)/(w) are about 1-2% higher than those determined according to the AAPM TG-25 protocol at φ(p)/(w) for clear or white polystyrene. Our calculated values of φ(p)/(w) also explain some of the variations of measured data because of its depth dependence. A simple formula is derived which gives the electron fluence correction factor φ(p)/(w) as a function of R50 at d(max) or at the depth of 0.6R50-0.1 for any clinical electron beam with energy between 5 and 25 MeV for three plastics: clear polystyrene, white polystyrene and PMMA. The study also makes a careful distinction between φ(p)/(w) and the corresponding IAEA Code of Practice quantity, h(m)

Determining the performance for an integrated process of COD removal and CO2 capture

Sludge water with high COD and CO emission in industry pollutes the environment. In order to effectively mitigate the COD and CO, this study developed an integrated process of COD removal and CO capture by utilizing CO to intensify the COD removal process. The mass transfer model and gas and liquid two phase flow model were developed and validated by the experiment. The dynamical characteristic, COD removal and CO capture performance were accurately investigated. The effect of the flue gas, Ca(OH) solution and sludge water on the COD removal and CO capture were discussed in detail. Due to the bond effect of Ca-O-C and large contact area, the highest CO capture efficiency reached 93.1% at simultaneous COD removal. The CO intensification effect on the COD removal was analyzed by the density functional theory. It was found that CO made the Ca(OH) remove COD more stably due to CO controlling the free ions. The CO and Ca(OH) regenerated efficiency respectively reached 85.3% and 88.9% by the electrochemical method

MO‐D‐204B‐06: Segmentation Evaluation in the Context of Inter-Physician Variance

info:eu-repo/semantics/publishe