The integrated academic information management system at Columbia-Presbyterian Medical Center.

Over the past seven years, Columbia-Presbyterian Medical Center has been planning and implementing an integrated academic information management system. Accomplishments to date include establishing an institutional information architecture, installing a campus-wide network of workstations, recruiting the staff needed to develop and implement the system, and developing various applications. This paper presents the rationale and steps involved in these accomplishments, as well as data on use of the system so far.     

Ultrasonic welding using tie-layer materials. part II: Factors affecting the lap-shear strength of ultrasonic welds

The influence of tie-layer Melt Flow Index on the lap-shear strength of ultrasonic welds in oriented polypropylene (OPP) has been evaluated. The tie-layer Melt Flow Index was varied from 0.03 dg/min to 2600 dg/min; the highest lap-shear strength properties were obtained using tie-layers that had melt flow index values between 30 and 100 dg/min. When using low Melt Flow Index tie-layers, hot spot formation and concomitant changes in fusion zone and heat-affected-zone dimensions produced stress concentrations that promoted failure in oriented polypropylene material away from the bondline region. When very high Melt Flow Index (2600 dg/min) tie-layers were used, the mode of failure during lap-shear testing was a mix of cohesive, in oriented polypropylene, and adhesive failure. The molecular weight of material at the bondline was not markedly affected by the thermal cycle produced during ultrasonic welding. Only the flash ejected when using low Melt Flow Index tie-layers exhibited any evidence of degradation; it is suggested that the ejected flash may have been degraded because of a combination of thermal, cavitation, and thermo-oxidative processes.     

PMMA tacticity and alumina powder dispersion stability

Summary Sedimentation experiments and X-ray photoelectron spectroscopy (XPS or ESCA) analyses have been used to study the effect of poly(methylmethacrylate) (PMMA) tacticity on aluminum oxide powder dispersion stability in a common solvent medium. The relative trends from sedimentation densities, and from surface analyses after solvent washing show that (PMMA) adsorption is greatest with isotactic polymer, where isotactic>atactic>syndiotactic adsorption. These results suggest that surface adsorption and hence dispersion stability can be influenced by polymer chain configuration as well as by chain conformation.     

Hot-carrier aging of the MOS transistor in the presence of spin-onglass as the interlevel dielectric

The effect of introducing a polysilicate or polysiloxane spin-on glass (SOG) as a component of the interlevel dielectric in a multilevel integrated circuit on the hot-carrier aging of the MOS transistor is discussed. It was found that the presence of SOG led to accelerated aging of the MOS transistor: factors of 20 and 5 for silicate and siloxane, respectively. This effect is attributed to water absorbed in the SOG films. a correlation was found for the hot-carrier aging rate and the amount of absorbed water     

Conformational effects in the reversed-phase chromatographic behavior of recombinant human growth hormone (rhGH) and N-methionyl recombinant human growth hormone (Met-hGH).

This paper examines the retention behavior of recombinant DNA-derived human growth hormone (rhGH) in reversed-phase chromatography and its separation from the closely related N-methionyl variant (Met-hGH). It is first shown that retention for rhGH decreases with increasing column temperature when 1-propanol (1-PrOH) is used as organic modifier. On the other hand, retention increases with temperature when acetonitrile (CH3CN) is employed. The differences in behavior for the two organic modifiers could be related to conformational changes in the protein as determined by solution and adsorption intrinsic fluorescence spectroscopy. Specifically, desorption and elution of rhGH using 1-PrOH could be correlated with a solvent-induced conformational change, with retention decreasing with increasing temperature due to the increasing ease of structural alteration. On the other hand for CH3CN the increase in retention correlated with temperature rise was related to a partial structural change yielding a more hydrophobic species. In this case, a surface-driven process is suggested. The work then turned to the separation of rhGH and Met-hGH where it was found for both organic modifiers optimum separation occurred at 45 degrees C and pH 6.5. Separate studies revealed that during the conformational change Met-hGH appeared more hydrophobic than rhGH since protein-protein aggregation was observed at a lower 1-PrOH concentration. It is suggested that this hydrophobic difference, which was optimized under the conditions cited above, resulted in the separation. The study demonstrates the importance of conformational changes in retention behavior and separation of protein samples.     

THE OPTIMUM SPEED OF VISUAL INSPECTION USING A RANDOM SEARCH STRATEGY

Choosing a standard speed for visual inspection is difficult using standard work measurement techniques. This paper uses a different approach, taking a model of human functioning in inspection and deriving an optimum speed of working so as to balance the cost of time against the cost of errors. Random search is used as the model and both self-paced and externally-paced conditions are derived for multiple fault types. Optimization using a Golden Section search is used to provide optimum inspection speed.     

Synthesis,Structure, and Physicochemical Properties of AI 4[UO2(CO3)3]·nH2O (AI = Li,Na, K,NH4)

Procedures for the synthesis of Li₄[UO₂(CO₃)₃]·1.5H₂O, Na₄[UO₂(CO₃)₃], K₄[UO₂(CO₃)₃], (NH₄)₄[UO₂(CO₃)₃], and K₃Na[UO₂(CO₃)₃] were optimized. The structures of these compounds and their thermolysis were studied by X-ray diffraction, precision IR spectroscopy, and thermal analysis. The standard enthalpies of formation of these compounds at 298.15 K were determined by reaction calorimetry.     

Dissociation of gaseous hydrates in beds

A mathematical model which accounts for the mobility of the liquid phase is constructed to describe the dissociation of gaseous hydrates in beds.Translated from Inzhenerno-fizicheskii Zhurnal, Vol. 60, No. 5, pp. 736–742, May, 1991.