Microstructure coarsening during static annealing of 60Sn40Pb solder joints: I stereology

The phase size distributions (PSDs) of the Sn, Pb, and the combined Pb and Sn phases, and the shape factor δ were determined for as-reflowed 60Sn40Pb solder joints and following their annealing at 50°C to 150°C. The PSDs in all cases had a positive skew which was approximated by a log-normal function. The PSDs were time invariant and were in accord with the Bitti and Nunzio model for phase coarsening. The shape factor, δ, decreased with the mean of the combined Pb and Sn phase size, and with temperature. Whether or not δ affects the PSDs is not clear.     

Numerical Simulation of Advected Thermal Using Gaussian-Vortex Model

The Gaussian-vortex integral model is applied to laboratory data on an advected thermal and field experimental data for a single submerged sewage outfall. The Gaussian-vortex integral model is distinguished from other conventional jet integral models that do not consider vortex-pair formation effects on the behavior of a buoyant jet in the buoyancy- and ambient-dominated regions. The experimental data relative to an advected thermal, measured by a laser-induced fluorescence technique were used for verifications of the numerical model. With the incorporation of vortex-pair formation effects, the simulated results on the bulk characteristics of an advected thermal were in good agreement with the laboratory data, and for applications the simulated surface minimum dilutions also show fairly good agreement with field experimental data. Finally, the numerical model is applied to a horizontal buoyant jet in cross-flow to demonstrate the capability of the numerical model for the buoyant jet that has 3D characteristics.     

Preparation and electrochromic properties of spin self-assembled polyelectrolyte multilayer films composed of PEDOT:PSS and PAH

Polyelectrolyte multilayer films composed of a polycation (poly(allylamine hydrochloride) PAH) and a polyanion (poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) PEDOT:PSS) were prepared by a spin self-assembly method, and their electrochemical and electrochromic properties were investigated. The change in the surface charge and the optical absorption spectra of the multilayer films revealed that sequential deposition of polyelectrolyte was successfully achieved during the spin self-assembly. The electrochromic properties of 20-bilayered PAH/PEDOT:PSS were also investigated. The response time for the coloring and bleaching processes was 6.2 and 2.5 s, respectively, and the coloration efficiency was 199.3 cm²/C. These results indicate that a spin self-assembly process could be a viable alternative for the fabrication of electrochromic devices.     

Antimicrobial properties of grape seed extracts and their effectiveness after incorporation into pea starch films

Chemical analysis and antimicrobial nature of grape seed extracts (GSE) and their Reisling Vitis vinifera L. application as fortificants for edible starch films were investigated. GSE possessed an antioxidant activity of 17.18 ± 1.29 mmol TROLOX equivalents g_extract⁻¹ and total phenolic content of 327.58 ± 7.24 mmol gallic acid equivalents g_extract⁻¹ mainly attributed to their flavonoid and phenolic acid composition determined by high-performance liquid chromatography accomplished to a diode array detector and a electrospray ionisation mass spectrometer in negative mode (HPLC-DAD/ESI-MS). GSE inhibited the growth of Gram-positive food-borne pathogens while Gram-negatives were not inhibited. After GSE were incorporated into pea starch films, thickness of enriched films increased and the puncture and tensile strength decreased compared to control films. Furthermore, migration of phenolic compounds from the films to different food simulants, aqueous, acidic and alcoholic solution was determined according to 89\109\EEC directive. A higher particle migration in acidic simulants was found. Finally, the effect of GSE incorporated pea starch films was tested in vitro with pork loins infected with Brochothrix thermosphacta. GSE films reduced the bacterial growth in 1.3 log colony forming units mL⁻¹ after 4 days incubation at 4 °C.     

Optical characteristics of undoped and Mn doped ZnS films

Undoped and Mn doped ZnS films were prepared in the temperature range 250–350°C by the spray pyrolysis technique. As the deposition temperature increased, the optical transmittance and the intensity of blue emission in the ZnS film were enhanced due to the decrease in the Zn/S ratio. By adding the manganese ion up to 7 at.% in the mixed solution, the orange-yellow emission of the films was enhanced. But the concentration quenching effect resulted in the decrease of the emission at higher concentration of the manganese ion.     

Perturbed Butterworth pole patterns for tracking in the sense of spheres

The so called “Quantitative Pole Placement” (QPP) identified in the context of guaranteed tracking in the sens of spheres is considered. In the prior literature this pole-placement problem was treated in a somewhat adhoc way. The primary purpose of the present work therefore is to propose a systematic procedure for such pole placement. The approach to the problem is based on a generalization of the standard LQ problem formulation. The preferred pole locations that minimize a crucial operator norm needed for the success of the QPP formulation are shown to be a perturbed version of the Butterworth pole configuration. The results are applied to a 3 d.o.f. robotic manipulator for illustrating the evolving methodology. At the center of the overall design philosophy is the need to directly satisfy performance specifications in uncertain. nonlinear systems.     

Nondestructive measurement of the coating thickness for simulated TRISO-coated fuel particles by using phase contrast X-ray radiography

The TRISO-coated fuel particle for a HTGR (high temperature gas-cooled reactor) is composed of a nuclear fuel kernel and outer coating layers. The coating layers consist of a buffer PyC (pyrolytic carbon) layer, an inner PyC (I-PyC) layer, a SiC layer, and an outer PyC (O-PyC) layer. X-ray radiography is one of the nondestructive alternatives to measure a coating thickness without generating a radioactive waste. Phase contrast X-ray radiography technology is more powerful for acquiring a radiograph with clear boundaries, when compared with a conventional X-ray radiography. The contrast can be enhanced for weakly absorbing materials in a phase contrast X-ray radiograph by detecting an intensity variation due to the variation of a phase of the X-rays in the boundary between two objects. Phase contrast X-ray radiograph was acquired from a simulated TRISO-coated fuel particle with a micro-focus X-ray imaging system. The coating thickness was nondestructively measured from the phase contrast X-ray image for the fuel particle.