In situ identification and analysis of automotive paint pigments using line segment excitation Raman spectroscopy: I. Inorganic topcoat pigments

Several applications of Raman spectroscopy in the forensic sciences have recently been demonstrated, but few have involved the analysis of paints. Undoubtedly, this is a reflection of the sample degradation problems often encountered when a visible or near-infrared laser is focused on a light-absorbing matrix. In this study, a dispersive CCD Raman spectrometer (785 nm) was used in a configuration which collected scattered light from an excitation region 3 mm long and 80 microm wide, instead of from a focused spot. Sample degradation was not observed, and Raman spectra of automotive paints of all colors were readily obtained. Most of the paints analyzed were U.S. automobile original finishes (1974 to 1989) from the Reference Collection of Automotive Paints, and the inorganic pigments examined were those which had been identified previously by infrared spectroscopy in finishes from this collection. Prominent peaks of rutile were observed in Raman spectra of light-colored nonmetallic finishes for both monocoats and basecoat/clearcoat systems, and the rutile peaks are readily distinguished from those of anatase. The lead chromates (Chrome Yellow, Molybdate Orange, and silica-encapsulated versions of the two) are the strongest Raman scatterers among the pigments examined, and Chrome Yellow was identified by Raman spectroscopy in several yellow and orange nonmetallic monocoats for which infrared absorptions of this pigment were not observed. Raman spectroscopy also provides an unequivocal means to distinguish Chrome Yellow from Molybdate Orange. This is particularly helpful for the analysis of paints containing light pigment loads or encapsulated pigments since the two formulations cannot be differentiated by infrared spectroscopy in such cases. The iron-containing pigments, ferric oxide, hydrous ferric oxide, and Prussian Blue, are relatively weak Raman scatterers, but peaks of hydrous ferric oxide and Prussian Blue were observed in spectra of paints containing heavy pigment loads. Because no sample preparation is required. Raman spectroscopy provides an excellent means to rapidly screen reference panels for the presence of certain pigments, and some examples of the differences in Raman spectra which occur for paints having similar colors are presented.     

Global uncertainty,economic governance institutions and foreign direct investment inflow in Africa

Economic Change and Restructuring - Based on the fact that Africa has not fared well in attracting foreign direct investments in the last decade compared to other regions of the world, especially...     

Juvenile Arrest and Later Economic Attainment: Strength and Mechanisms of the Relationship

Journal of Quantitative Criminology - We tested the impact of juvenile arrest on asset accumulation, debt accumulation, and net worth from ages 20–30. We also examined whether indicators of...     

Distributional effects of dollarisation: the Latin American case

Over the past two years Ecuador, El Salvador and Guatemala have adopted the US dollar as a legal currency in their countries. Several other Latin American countries, including Argentina, are currently discussing dollarisation. In this policy paper we look at the existing evidence for answers to two basic questions. First, under what general circumstances might dollarisation make sense? Second, are there clearly differentiated winners and losers from dollarisation and, if so, can we identify them, so that policy can take these political economy factors into consideration? Our review of the evidence demonstrates that there are consistent patterns of distributional effects, both positive and negative, from the choice of exchange rate regime. These effects are presently not considered in exchange rate policy decision making, but should be. While the effects are not as pronounced as those from major trade liberalisation agreements, they are significant. Ways to cushion the effects of exchange rate regime choice should be considered in the future by policy makers. Moreover, we find that dollarisation is embedded in the politics of the region. Dollarisation is often sold as a substitute for the deeper institutional reforms needed to improve economic performance and distribution in Latin America.