Laser-induced Fluorescence Spectroscopy of NiO between 510 and 650 nm

Laser-induced fluorescence excitation spectra of NiO have been recorded in the wavelength region of 510-650 nm under supersonic molecular beam conditions. More than fifty bands have been observed and rotationally analyzed to determine the molecular constants. The excited states exhibit highly irregular variations in terms of isotopic shifts, vibrational intervals, and rotational constants. Twenty-six bands attributed to [Ω=0, 1]-X3∑o transitions have been tentatively grouped into five vibrational progressions. Furthermore, dispersed fluorescence and lifetimes of the strong bands have also been measured.

ULTRASOUND INDUCED AND LASER ENHANCED COLD FUSION CHEMISTRY

The standard model of sonoluminescence suggests that the Coulomb barrier to deuterium fusion may be overcome by high bubble gas temperatures caused by compression heating if the bubble diameter remains spherical during bubble collapse.However, in the more likely collapse geometry of a pancake shape, the temperature rise in the bubbles is negligible. But the collapsing pancake bubble is found to significantly increase the frequency of the infrared energy available in the vibrational state of the water molecules at ambient temperature. For a collapse to liquid density, ultraviolet radiation at about 10eV is found. Although the ultraviolet radiation is of a low intensity, higher intensities may be possible if the bubble collapse is enhanced by visible and infrared lasers. Neither hot nor cold fusion is predicted in bubble collapse,but the ultraviolet energy at about 10eV developed in the bubble is sufficient to provide the basis for a new field of chemistry called ultrasound induced and laser enhanced cold fusion chemistry.

Effects of Ultrasound on the Weld Bead Surface of High Carbon Steel Sheets

Power ultrasound is finding widespread applications in assisting conventional processes yielding products of better quality at lower processing power and temperature. Transmission of ultrasound is known to be affected by the boundaries between layers of different materials or same material but in different states （solid or liquid or gas）. This paper investigates the effects of ultrasound （US） on the surface of the solidified weld which has been subjected to ultrasonic vibrations of 20 kHz frequency during laser welding. Vibrations due to ultrasound normally exert a very high force which is usually hundred or thousand times the gravity. The transverse waves will also cause movement of molten material in the weld. As the surface of the weld beads were of interest and not the mechanical properties and the microstructure, investigation of bead on plate welds were found to be sufficient. High carbon steel plate was held at one end by the ultrasonic horn through which ultrasound was injected. A bead on plate weld using a CO2 laser （1 kW） was then performed along the center of the plate using three different welding speeds namely, 400, 1200 and 2000 mm per minute. The ultrasonic powers selected were 3 W and 6 W respectively for each welding speed as higher acoustical power was causing ejection of molten metal from the pool during welding. 3D surface measurements and analysis were then made on a section of length 20 mm using a Talysurf machine. The results show that the surface of the weld was affected to different extent depending on the positions being considered in the weld. Some regions were similar to the reference weld whereas some specific regions were heavily disrupted with deep valleys followed by high peak/s. This shows that US vibration of weld pools, even at very small acoustical power, is a more complex problem than other similar processes such as casting because of the very small volume of molten metal involved.

Prediction of Compressive Strength Using Ultrasonic Pulse Velocity for CLSM with Waste LCD Glass Concrete

The purpose of this paper is to develop a prediction model of WGCLSM （waste LCD （liquid crystal display） glass controlled low strength materials） concrete, the relationship between UPV （ultrasonic pulse velocity） and compressive strength, UPV-strength model. The power function was used to perform the nonlinear-multivariate regression analysis of UPV with water-binder ratio （w/b）, curing age （t） and waste glass content （G） in our previous study. Test results show that the compressive strength increases with UPV and approach to a linear relationship. Thus, the UPV-strength model was established by linear-multivariate regression analysis and the compressive strength evaluated by ultrasonic pulse velocity. The calculated results are in accordance with the laboratory measured data ultrasonic pulse velocity and compressive strength. In addition, the statistical analysis shows that the coefficient of determination R2 and the MAPE （mean absolute percentage error） were from 0.916 to 0.951 and 12.6% to 15.1% for the compressive strength, respectively. The proposed models are highly accurate in predicting the compressive and ultrasonic pulse velocity of WGCLSM concrete. However, with other ranges of mixture parameters, the predicted models must be further studied.