Isolation and identification of mutagenic nitro-pah in diesel-exhaust particulates

More than 50 nitro-PAH have been tentatively identified in an extract of diesel-exhaust particulates. Identifications are based on high-resolution mass spectrometry of directly mutagenic fractions derived from sequential fractionation of the extract by both low- and high-resolution liquid chromatography. The diversity of nitro-PAH tentatively identified suggests that large numbers of such compounds are formed during or following the combustion process.     

In Memoriam

I sketch the rich life and multifaceted work of Philip Morrison (1915–2005), from his early life in Pittsburgh, Pennsylvania, and higher education at the Carnegie Institute of Technology and the University of California at Berkeley, to his contributions to the Manhattan Project, his research at Cornell University and the Massachusetts Institute of Technology after the war, his subsequent political activity on behalf of nuclear disarmament, his role in the search for extraterrestrial intelligence, and his enormous influence as an educator, public speaker, and writer. A.P. French is Professor of Physics, Emeritus, at the Massachusetts Institute of Technology.     

Comparison of soil strength measurements of agricultural soils in Nebraska

In 2014 the University of Nebraska, Lincoln (UNL) was engaged in field testing program to investigate a soil moisture mapping system as a crop management tool. In conjunction with this work, the US Army Engineer Research and Development Center, Cold Regions Research and Engineering Laboratory (ERDC-CRREL) deployed a team to perform soil characterization and strength measurements at three agricultural test sites. The primary objective was an investigation of the Lightweight Deflectometer (LWD) as a soil surface strength tool for the purposes of assessing bearing capacity of soft soils. The LWD measurements were performed with those from more “standard” tests, i.e. the Dynamic Cone Penetrometer, Cone Penetrometer, and Clegg Impact Hammer to determine if the LWD produced results that compared with these methods. The strength test data were also used to calculate California Bearing Ratio (CBR) values using existing equations in order to see if the different test methods produced similar CBR values that could in turn be used to predict the bearing capacity of the sites. The secondary objective was to compare the strength data with the corresponding soil water content data taken by UNL to determine if soil moisture was an indicator of soil strength.