Light scattering detector

The invention concerns high sensitivity light scattering detection and its application to evaporative light scattering detection in liquid chromatography. The exemplary embodiment includes a detection cell to accept particles suspended in a gas stream and permit a polarized light beam to pass through a trajectory of the particles and gas stream. A sample light detector is disposed to detect light scattered in the detection cell. A light trap accepts the polarized beam after it passes through the detection cell. The light trap includes an elongated housing through which the polarized beam passes, and light absorptive material within the elongated housing. An absorptive filter is aligned such that the angle of incidence of the light beam upon the filter approximates Brewster\u27s angle and the electric field vector of the beam is aligned with the plane of incidence between the beam and the filter. Other embodiments of the invention provide increased light collection. Embodiments of the invention include temperature-controlled entrance and exit ports that control particle trajectory. Embodiments of the invention include a reference cell disposed between a detection cell and a light trap, and the reference cell includes lensing and a spherical mirror to direct light toward a reference light detector. The reference light detector provides a reference signal that may be used with noise cancellation circuitry, operating in either voltage or current mode, to reduce light source noise in the sample signal.https://irl.umsl.edu/patents/1059/thumbnail.jp

Light Scattering Detector

The invention concerns high sensitivity light scattering detection and its application to evaporative light scattering detection in liquid chromatography. The exemplary embodiment includes a detection cell to accept particles suspended in a gas stream and permit a polarized light beam to pass through a trajectory of the particles and gas stream. A sample light detector is disposed to detect light scattered in the detection cell. A light trap accepts the polarized beam after it passes through the detection cell. The light trap includes an elongated housing through which the polarized beam passes, and light absorptive material within the elongated housing. An absorptive filter is aligned such that the angle of incidence of the light beam upon the filter approximates Brewster\u27s angle and the electric field vector of the beam is aligned with the plane of incidence between the beam and the filter. Other embodiments of the invention provide increased light collection. Embodiments of the invention include temperature-controlled entrance and exit ports that control particle trajectory. Embodiments of the invention include a reference cell disposed between a detection cell and a light trap, and the reference cell includes lensing and a spherical mirror to direct light toward a reference light detector. The reference light detector provides a reference signal that may be used with noise cancellation circuitry, operating in either voltage or current mode, to reduce light source noise in the sample signal.https://irl.umsl.edu/patents/1060/thumbnail.jp

Ultrasensitive Spectrophotometer

The invention concerns measurements in which light interacts with matter to generate light intensity changes, and spectrophotometer devices of the invention provide ultrasensitive measurements. Light source noise in these measurements can be reduced in accordance with the invention. Exemplary embodiments of the invention use sealed housings lacking an internal light source. In some embodiments a substantially solid thermally conductive housing is used. Other embodiments include particular reflection based sample and reference cells. One embodiment includes a prism including an interaction surface, a detector, a lens that focuses a prism beam output onto the detector, and a closed interaction volume for delivering gas or liquid to the interaction surface. Another embodiment replaces a prism with a reflective surface. Another embodiment replaces a prism with a scattering matte surface. Aspects of the invention identify noise-contributing components in spectrophotometry and realize noise levels very near the shot noise limit.https://irl.umsl.edu/patents/1058/thumbnail.jp

Balls, Strikes, and Norms: Rule Violations and Normative Rules Among Baseball Umpires

This study investigated the use of normative rules by baseball umpires. Normative rules are informal standards of conduct that deviate from the official rules of sport. Sixteen umpires, 25 coaches, and 27 baseball players defined the official upper and lower boundaries of the strike zone, marked these official boundaries on a Strike Zone Form, and marked where they actually call, or believe umpires call, the boundaries. Umpires were significantly more knowledgeable about rules than players were. Umpires reported setting the upper boundary of the strike zone significantly lower (an average of 2.64 inches) than the official rule specifies. Coaches and players reported that umpires lower the boundaries, but players overestimated how much umpires deviate from the rule-book boundaries. Results suggest that umpires consciously violate official rules. The ethical implications of these findings are discussed

Judgment Bias in Baseball Umpires First Base Calls: A Computer Simulation

Tested 39 baseball umpires and 39 undergraduates, using a computer simulation of 1st-base calls to determine the role of the prior entry phenomenon in close plays. Because umpires are directed to focus their attention on an auditory stimulus (ball hitting the glove), they may experience prior entry of the auditory stimulus, resulting in safe runners being called out. There were more errors when runners were just safe and safe because of a tie than when runners were just out, indicating that prior entry occurred in the simulations. This was more pronounced among umpires than controls

Geographical Diversification: An Application of Copula Based CVaR

Risk and Uncertainty,

NMR Investigations Of Aggregation Of Nonionic Surfactants In A Hydrocarbon Medium

Proton NMR, carabon-13 NMR, light-scattering, and density measurements were used to investigate association structures and molecular interactions during water solubilization in polyoxymethylene dodecyl ether/benzene systems at high surfactant concentrations. The results indicated an absence of association aggregates at low water concentrations. At water contents between 10 and 20%, association structures started to form, probably micelles of the inverse type, in which the water-polyoxymethylene chain interaction is the predominant feature. There is evidence that the average chain conformation changes with water content, and that bound water molecules are distributed evenly along the polyethoxyethylene chain. At higher water concentration, the results indicated a water-rich core to be formed, supported by the close resemblance of the water properties to these of native water. © 1980 American Chemical Society

Lyotropic Liquid Crystals From Lecithin, Water, And Polyethylene Glycol

Lyotropic liquid crystals with lecithin as the amphiphile and with water/polyethylene glycol (PEG) solutions as the solvent were prepared with polyethylene glycol/water ratios from 182 to 0. The liquid crystals were lamellar and the interlayer spacing was independent of the solvent content for water/PEG ratios ≤1 but increased strongly with the water/PEG ratio. Higher ratios gave increased interlayer spacing with solvent content similar to the variation for liquid crystals with water as solvent but the absolute values of the spacing were higher. © 1984 Academic Press, Inc. All rights reserved

Dynamic Structure Of A Nonaqueous Lamellar Liquid Crystal: Comparison With The Aqueous Case

The lamellar phase of sodium dodecyl sulfate/decanol/glycerol has been compared to the analogous water-based system. Results of NMR studies of deuteriated alcohol and surfactant showed the bilayer to be more disordered in the nonaqueous case than in the phase made with water. The order profiles of the two systems, however, were of the same form, implying that the same essential packing requirements applied to each case. The overall increase in dynamic disorder observed in the glycerol system is a result of a transversely more disordered bilayer/solvent interface. © 1987, American Chemical Society. All rights reserved