Application of a computer-based chromatograph for automated water pollution analyses.

A modified head-space analysis technique, coupling thermal extraction with subsequent adsorption of organics on a poly (para 2,6-diphenyl phenylene) oxide adsorbent (Tenax-GC), has been found to be an efficacious tool when combined with gas chromatography for the study and monitoring of low molecular weight organics present in drinking water supplies (1-4). This procedure has allowed for the analysis of volatile organics in the low parts-per-billion range from 1 liter or less of tap water. Because thermal extraction requires smaller sample sizes than required in carbon-chloroform extraction methods and liquid/liquid extractions, the EPA has recently adopted this type of methodology (5,6). Passage of the Safe Water Drinking Act in December of 1974 has mandated that each state assumes the primary responsibility for carrying out the purposes of the legislation (7). Because the Act says that any supplier of water serving 25 individuals or more must comply with these regulations, large-scale monitoring programs will have to be undertaken. It was thus our desire to try to simplify the sample collection and data acquistion and reduction processes as much as possible, in the effort to make the procedure more adaptable for incorporation into routine monitoring programs. Also, automation reduces the experience and number of personnel required to perform the analyses. In addition to analysis of drinking water samples, the automated procedure described hereinafter can also be applied to monitoring industrial plant effluents, waste water treatment processes, and general quality control monitoring of low molecular weight organic compounds.     

Search for finite-mass neutrinos in the decay π+→μ+vμ

If neutrinos possess non-zero mass, pion decay might have small decay branches to neutrino states with large masses. We have searched for such branches in the decay of pions produced at the Indiana University Cyclotron. The energy spectrum of decay muons shows no evidence for such neutrino branches and if these decays do exist, their branching ratios must be less than 10^?2 to 10^?3 for neutrino masses in the ranFge 7–33 MeV.     

Iodine magnetic moments measured by on-line nuclear orientation

On-Line measurements of magnetic dipole moments of^117–122I are interpreted using coupling of the odd particles to a deformed core. The results show interesting effects of g_7/2, d_5/2 orbital admixtures in the odd-A isotopes, which are close to spherical. The odd-odd isotopes^{118, 120}I show clear examples of shape co-existence.     

The mechanics of non-linear materials with memory

Archive for Rational Mechanics and Analysis -     

A study of the synthesis of triazoles using microwave irradiation

Herein we describe the conversion of a known [3+2] cycloaddition reaction between an azide and an acetylene from a thermally promoted reaction to a microwave assisted process. Modification of conditions including concentration, temperature, solvent type and time were investigated. This methodology study led us to use high concentration and high temperatures to achieve the desired fast reaction times and high yields.     

Expert system assisted pharmacophore identification

An expert system for automatic perception of pharmacophoric groups is presented. Important features include consideration of the protonation state at physiological pH and detection of potential tautomerism. This perception information is used in the generation of pharmacophores using clique detection.