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In this paper we present near-infrared absorption, thermal emission, and laser-induced fluorescence spectra obtained in high density sodium–potassium mixtures. These spectra are compared to spectra calculated from recently published NaK potentials and dipole moments and the agreement is seen to be quite good. We have also observed significant laser-induced fluorescence to the red of the 2 1∑+ → 1 1∑+ NaK band (A band). From laser power and density dependences of this long-wavelength fluorescence, as well as from comparison to calculated spectra, we have tentatively identified this emission as the lowest NaK triplet band 1 3∏ → 1 3∑+ which has not previously been reported. We have also observed a shoulder or satellite feature in potassium vapor under similar conditions. It is possible that this is a potassium trimer emission band. [ABSTRACT FROM AUTHOR]

Skin friction (cf) and heat transfer (St) predictions were made for a turbulent boundary layer over randomly rough surfaces at Reynolds number of I x 106. The rough surfaces are scaled models of actual gas turbine blade surfaces that have experienced degradation after service. Two different approximations are used to characterize the roughness in the computational model: the discrete element model and full 3D discretization of the surface. The discrete element method considers the total aerodynamic drag on a rough surface to be the sum of shear drag on the flat part of the surface and the form drag on the individual roughness elements. The total heat transfer from a rough surface is the sum of convection on the flat part of the surface and the con vçction from each of the roughness elements. Correlations are used to model the roughness element drag and heat transfer, thus avoiding the complexity of gridding the irregular rough surface. The discrete element roughness representation was incorporated into a two-dimensional, finite difference boundary layer code with a mixing length turbulence model. The second prediction method employs a viscous adaptive Cartesian grid approach to fully resolve the three-dimensional roughness geometry. This significantly reduces the grid requirement compared to a structured grid. The flow prediction is made using a finite-volume Navies- Stokes solver capable of handling arbitrary grids with the Spalart-Allmaras (S-A) turbulence model. Comparisons are made to experimentally measured values of cf and St for two unique roughness characterizations. The two methods predict cf to within ± 8% and St within ± 17%, the RANS code yielding slightly better agreement. In both cases, agreement with the experimental data is less favorable for the surface with larger roughness features. The RANS simulation requires a two to three order of magnitude increase in computational time compared to the DEM method and is not as readily adapted to a wide variety of roughness characterizations. The RANS simulation is capable of analyzing surfaces composed primarily of roughness valleys (rather than peaks), a feature that DEM does not have in its present formulation. Several basic assumptions employed by the discrete element model are evaluated using the 3D R.4NS flow predictions, namely: establishment of the midheight for application of the smooth wall boundary condition; cD and Nu relations employed for roughness elements; and flow three dimensionality over and around roughness elements. [ABSTRACT FROM AUTHOR]

Delayed wound healing is one of the complications of diabetes mellitus, exhibited by increased wound collagenase and decreased granulation tissues. The current study compared wound healing in normal and diabetic rats, and the effects of topically applied 1% or 3% concentrations of chemically modified tetracycline-2 (CMT-2) on 6-mm circular full-thickness skin wounds healed by secondary intention. On day 7 after wounding, tissues were removed for biochemical analysis and histology. The wound granulation tissue hydroxyproline was less in the untreated diabetic rat with increased collagenase and gelatinase. Treating the diabetic rat wounds with 3% CMT-2 increased the wound hydroxyproline and decreased activities of gelatinase and collagenase. There was a delay in wound filling by granulation tissue in diabetic rats. In CMT-2-treated diabetic rats, the volume of granulation tissue was greater than that in untreated diabetic rats. CMT-2 appears to normalize wound healing in diabetic rats and may be a valuable adjunct in the treatment of chronic wounds. [ABSTRACT FROM AUTHOR]

To evaluate and quantify snowmobile noise, measurements were made as follows: (1) operator at-ear A-weighted sound levels and exposure patterns; (2) A-weighted levels at 50 ft to develop a test procedure for law enforcement purposes; (3) temporary threshold shift (TTS) in snowmobile users. Results indicate that (a) TTS of varying degrees was observed in 87% of snowmobile operators tested after operations periods as short as one-half hour; (b) for typical recreational riding, the Federal Occupational Safety and Health Act of 1970 noise limits are exceeded after approximately 2 1/2 hours of snowmobile operation; (c) the 50-ft noise-level measurement procedure which was developed can probably be used as a valid test procedure to measure the amount of noise produced by a snowmobile for law enforcement purposes. More correlation of data would be desirable. [ABSTRACT FROM AUTHOR]