Real time estimation of CO2 laser weld quality for automotive industry

Laser welding is one of the most precise welding processes in joining sheet metals. In laser welding, performing real time evaluation of the welding quality is very important to enhance the efficiency of the welding process. In this study, the plasma and spatter, which are generated during laser welding, are measured using UV and IR photodiodes. The factors that influence weld quality are classified into five categories; optimal heat input, slightly low heat input, low heat input, partial joining due to gap mismatch, and nozzle deviation. The data number deviated from reference signals and their standard deviations were also considered to evaluate the qualities. A system was also formulated to perform real time evaluations of the weld quality using a fuzzy multi-feature pattern recognition with the measured signals.     

Comparative preparations of homoleptic hydridic anions of iron and ruthenium using solution-based organometal hydrogenation techniques

A study of the preparations of the complex hydridic anions [MH(6)](4)(-) (M = Fe and Ru) reveals a number of distinctive features. Here a soluble homoleptic ruthenium hydride has been prepared for the first time. For example, both FeX(2) and [Ru(eta(4)-1,5-COD)X(2)], X = Cl and Br, react with PhMgBr solutions under hydrogen to produce the title compounds. The benzene liberated in these reactions is more readily hydrogenated in the case of a homogeneous room temperature ruthenium hydride preparation to both cyclohexane and cyclohexene. The (1)H NMR spectroscopic data show that the two complex anions have hydride absorptions in the low-frequency region, delta -20.3 and -14.7, respectively. Further, (1)H spin-lattice relaxation times (T(1)) for M-H are longer in the case of Ru vs Fe.     

Luminescent Sensing with Quantum Dots

Summary This review highlights recent advances in the use of quantum dots (QD’s) as luminescent sensors. The bulk of the study concentrates on systems that possess organic ligands bound to the surface of QD’s. These ligands vary from low molecular weight thiols to larger molecules such as maltose binding protein. All have one thing in common: when a target analyte binds to the ligand/receptor, a perturbation of the system occurs, that registers itself as a change in the luminescence intensity of the QD. Two main mechanisms are prevalent in controlling the luminescent intensity in such systems. The first is Photoinduced Electron Transfer (PET) and the second energy transfer. This review looks at current sensors that operate by using these mechanisms. Two component systems are also investigated where a quencher is first added to a solution of the QD, followed by addition of the target analyte that interacts with the quencher to influence the luminescence intensity.     

Electron-photon polarisation correlations in 140 eV electron impact excitation of helium

Electron-polarised photon coincidence techniques are used to determine linear and circular polarisation correlations from the differential electron impact excitation of the 2¹ P state of helium at an incident electron energy of 140 eV. At 30° and 45° electron scattering angles, all the Stokes parameters are determined, whereas at 52.5° onlyP ₂ is measured. Comparisons are made with the distorted wave (DW) calculations of Madison [11] and the first order many-body theory (FOMBT) of Cartwright and Csanak [4].     

A chemical inhibitor reveals the role of Raf kinase inhibitor protein in cell migration

Raf kinase inhibitor protein (RKIP) is a modulator of cell signaling that functions as an endogenous inhibitor of multiple kinases. We demonstrate here a positive role for RKIP in the regulation of cell locomotion. We discovered that RKIP is the relevant cellular target of locostatin, a cell migration inhibitor. Locostatin abrogates RKIP's ability to bind and inhibit Raf-1 kinase, and it acts by disrupting a protein-protein interaction, an uncommon mode of action for a small molecule. Small interfering RNA-mediated silencing of RKIP expression also reduces cell migration rate. Overexpression of RKIP converts epithelial cells to a highly migratory fibroblast-like phenotype, with dramatic reduction in the sensitivity of cells to locostatin. RKIP is therefore the compound's valid target and a key regulator of cell motility.