Optical errors in a liquid chromatography absorbance cell

The shadowgraph method is used to visualize mobile phase flow through a liquid chromatography absorbance cell with "Z" flow geometry. It is shown that mixing is incomplete in the cell. Composition gradients persist throughout the elution of any sample. The gradients systematically change as the sample flows through the cell. Additionally, window wedge angles are measured in several cells. The implications for low noise absorbance detectors are discussed.     

INVESTIGATION OF A QUASI-STEADY LIQUID CRYSTAL TECHNIQUE FOR FILM COOLING HEAT TRANSFER MEASUREMENTS

A quasi-steady technique to simultaneously measure the local heat transfer coefficient and cooling effectiveness on surfaces involving film cooling situations is investigated. The method employs a composite slab consisting of a very thin laminate layer of low-thermal-conductivity material superposed upon a highly conductive metal substrate. The resulting heat transfer in the thin laminate is described by one-dimensional conduction. A very thin coating of thermochromic liquid crystals sprayed onto the surface of the laminate is used in conjunction with a computer image processing procedure to provide local surface temperature data. This information, combined with the substrate and mainstream gas temperatures, provides highly detailed (90 video pixels/cm²) local convection heat transfer distributions. The method is used to conduct flat-plate film cooling experiments consisting of a single row of discrete holes inclined at 35 to the mainstream flow. The local surface temperature is influenced by the combination of two interacting fluid streams at different temperatures. A numerical analysis was performed to assess the assumptions underlying the data reduction procedure. The experimental uncertainty of 7% in the heat transfer coefficient is comparable to prior studies. Furthermore, the uncertainty of 5% in the film cooling effectiveness, coupled with the negligible lateral conduction errors, indicates the present technique offers a unique capability for accurate measurement of the local film cooling effectiveness.     

A strategic r&d planning model with an application to an energy research organization

This paper describes a two-stage strategic planning model for determining the optimal R&D portfolio in the presence of both exploratory and developmental research projects. An example is illustrated in the context of energy research. Research portfolios are analysed using a Bayesian approach in which probability assessments are updated as new information generated by exploratory research becomes available. Useful insights are obtained through sensitivity analysis. It is found that exploratory research tends to exhibit a lumpy characteristic.     

Unraveling virus identity by detection of depleted probes with capillary electrophoresis

With the emergence of new viral infections and pandemics, there is a need to develop faster methods to unravel the virus identities in a large number of clinical samples. This report describes a virus identification method featuring high throughput, high resolution, and high sensitivity detection of viruses. Identification of virus is based on liquid hybridization of different lengths of virus-specific probes to their corresponding viruses. The probes bound to target sequences are removed by a biotin–streptavidin pull-down mechanism and the supernatant is analyzed by capillary electrophoresis. The probes depleted from the sample appear as diminished peaks in the electropherograms and the remaining probes serve as calibrators to align peaks in different capillaries. The virus identities are unraveled by a signal processing and peak detection algorithm developed in-house. Nine viruses were used in the study to demonstrate how the system works to unravel the virus identity in single and double virus infections. With properly designed probes, the system is able to distinguish closely related viruses. The system takes advantage of the high resolution feature of capillary electrophoresis to resolve probes that differ by length. The method may facilitate virus identity screen from more candidate viruses with an automated 4-color DNA sequencer.     

Analysis of some binary and ternary oxide mixtures by inelastic neutron scattering

Aluminium, iron and silicon have been determined in a number of binary and ternary oxide mixtures at levels>1% by measuring the gamma-lines emitted as a result of inelastic neutron scattering.