Trasmission and Reflection (ATR)Far-Infrared Spectroscopy Applied in the Analysis of Cultural Heritage Materials

FIR spectroscopy is an alternative way of collecting spectra of many inorganic pigments and corrosion products found on art objects, which is not normally observed in the MIR region. Most FIR spectra are traditionally collected in transmission mode but as a real novelty it is now also possible to record FIR spectra in ATR (Attenuated Total Reflectance) mode. In FIR transmission we employ polyethylene (PE) for preparation of pellets by embedding the sample in PE. Unfortunately, the preparation requires heating of the PE in order to produces at transparent pellet. This will affect compounds with low melting points, especially those with structurally incorporated water. Another option in FIR transmission is the use of thin films. We test the use of polyethylene thin film (PETF), both commercial and laboratory-made PETF. ATR collection of samples is possible in both the MIR and FIR region on solid, powdery or liquid samples. Changing from the MIR to the FIR region is easy as it simply requires the change of detector and beamsplitter (which can be performed within a few minutes). No preparation of the sample is necessary, which is a huge advantage over the PE transmission method. The most obvious difference, when comparing transmission with ATR, is the distortion of band shape (which appears asymmetrical in the lower wavenumber region) and intensity differences. However, the biggest difference can be the shift of strong absorbing bands moving to lower wavenumbers in ATR mode. The sometimes huge band shift necessitates the collection of standard library spectra in both FIR transmission and ATR modes, provided these two methods of collecting are to be employed for analyses of unknown samples. Standard samples of 150 pigment and corrosion compounds are thus collected in both FIR transmission and ATR mode in order to build up a digital library of spectra for comparison with unknown samples. XRD, XRF and Raman spectroscopy assists us in confirming the purity or impurity of our standard samples. 24 didactic test tables, with known pigment and binder painted on the surface of a limestone tablet, are used for testing the established library and different ways of collecting in ATR and transmission mode. In ATR, micro samples are scratched from the surface and examined in both the MIR and FIR region. Additionally, direct surface contact of the didactic tablets with the ATR crystal are tested together with water enhanced surface contact. In FIR transmission we compare the powder from our test tablet on the laboratory PETF and embedded in PE. We also compare the PE pellets collected using a 4x beam condenser, focusing the IR beam area from 8 mm to 2 mm. A few samples collected from a mural painting in a Nepalese temple, corrosion products collected from archaeological Chinese bronze objects and samples from a mural paintings in an Italian abbey, are examined by ATR or transmission spectroscopy

The Impact of Alcohol Consumption and Marijuana Use on High School Graduation

In this study we use data from the National Longitudinal Survey of Youth (NLSY). We estimate the relationship between high school graduation, and alcohol and marijuana use among the sample of high school students. We also estimate these students' demand determinants for each of these substances. Our results show that there are significant adverse effects of alcohol and marijuana use on high school graduation. In addition, we find that beer taxes, minimum drinking age laws and marijuana decriminalization have a significant impact on the demand for these substances. Our findings have important policy implications. We find that a ten percent increase in beer tax, reduces alcohol consumption among high school students, which in turn raises the probability of high school graduation by about 3.7 percent. Further, a ten percent increase in liquor prices, raises the probability of high school graduation by 6.6 to 8.2 percent. Raising the minimum drinking age for liquor also reduces liquor and wine consumption, and consequently, improves the probability of high school graduation.

Oil industry consolidation and refined product prices: Evidence from US wholesale gasoline terminals

Our objective in this paper is to quantify the impact of petroleum industry consolidation on refined product prices, controlling for other important factors that could also impact prices. Our empirical analysis focuses on the US petroleum refining industry using data on industry consolidation and wholesale gasoline prices collected over the interval 2000-2008. We match refinery units to wholesale city-terminal gasoline markets, and then estimate pooled cross-section time-series regressions to quantify the impact of petroleum industry consolidation on wholesale gasoline prices at city-specific terminals. The results of the empirical analysis of mergers are mixed, showing that some petroleum industry mergers resulted in statistically significant increases in refined product prices; others resulted in statistically significant declines and still others had no statistical impact at all. Our analysis of the effects of measures of market concentration--one at the level of city-specific wholesale terminals and another at the level of regional spot markets--found evidence that less concentrated markets are associated with lower price levels.Petroleum refining Oil industry mergers Fuel prices

Estimating the impact of refinery outages on petroleum product prices

We quantify the impact of refinery outages on petroleum product prices. The empirical analysis focuses on wholesale gasoline prices in the US using weekly data collected from January 2002 through September 2008, a period including many refinery outages. We match refinery unit output to specific wholesale gasoline markets, and then estimate panel data regressions to quantify the impact of refinery unit outages on wholesale gasoline prices while controlling for time-specific effects, city-specific effects, fuel-specific effects, refinery concentration, and other factors that could impact the price of refined petroleum products. The estimation results show that refinery outages have a statistically significant positive impact on refined product prices, and that the magnitude of this effect is larger for certain special fuel blends. Policy implications are discussed.Refinery outages Gasoline prices Boutique fuels