Precision mounting for instrument optical elements provided by polyimide bonding

Epoxy resin-coated polyimide plastic is used for bonding materials with different thermal coefficients in applications requiring precision mounting, especially where vibrations, temperature extremes, and low pressures are encountered. Low vapor pressure of the bonding material precludes outgassing problems

The structure of separated flow regions occurring near the leading edge of airfoils, including transition

The structure and behavior of the separation bubble including transition and the redeveloping boundary layer after reattachment over an airfoil at low Reynolds numbers was studied. The intent is to further the understanding of the complex flow phenomena so that analytic methods for predicting their formation and development can be improved. These analytic techniques have applications in the design and performance prediction of airfoils operating in the low Reynolds number flight regime

Laser velocimetry measurement in a transonic tunnel

Some preliminary velocity measurements were carried out inside the transonic tunnel using the laser velocimeter (LV) system in association with the smoke generator. Pressure measurements were also performed using a pressure tap located on the side wall of the test section slightly upstream of the windows. Though the pressure measurements and the LV measurements were not taken at exactly the same location, extrapolation of the pressure data into the location of the LV measurements indicated a very close agreement between the velocity values obtained using the two different methods. Thus it is believed that the smoke particle is following the air flow with little or no velocity slip. Velocity measurements with airfoil at various angles of attack are now being carried out in conjuction with schlieren flow visualization. In the near future pressure distribution around and on the airfoil will be obtained by putting pressure taps on the side windows and using a pressure tap model (currently under construction) of the airfoil

Non-spherical core collapse supernovae and nucleosynthesis

Motivated by observations of supernova SN 1987A, various authors have simulated Rayleigh-Taylor (RT) instabilities in the envelopes of core collapse supernovae (for a review, see Mueller 1998). The non-radial motion found in these simulations qualitatively agreed with observations in SN 1987A, but failed to explain the extent of mixing of newly synthesized 56Ni quantitatively. Here we present results of a 2D hydrodynamic simulation which re-addresses this failure and covers the entire evolution of the first 5 hours after core bounce.Comment: 4 pages, 1 figure, LaTeX, requires espcrc1.sty. To appear in Nucl. Phys. A., the proceedings of the conference "Nuclei in the Cosmos 2000", held in Aarhus, Denmark, June 27-July 1, 200

ST2 in Stable and Unstable Ischemic Heart Diseases

Circulating suppression of tumorigenicity 2 (ST2) predicts cardiovascular outcomes and mortality in ischemic heart disease (IHD). ST2 does not correlate with traditional risk indicators as closely as N-terminal pro–brain natriuretic peptide (NT-proBNP) and is only weakly correlated with other biomarkers, indicating distinct pathways for stimulus and release. Although of little diagnostic utility in IHD, ST2 does offer prognostic information. In ST elevation myocardial infarction, ST2 levels increase to peak above the normal reference range (within 6 to 18 hours of symptom onset) in about half of patients. Levels in the upper quartile observed in IHD independently predict cardiovascular death and heart failure with an approximate doubling of risk. Similar but weaker associations have been reported in non–ST elevation myocardial infarction, in which ST2 predicts short-term (30-day) and long-term (>1-year) death and heart failure independent of clinical indicators, but these relations are lost if Global Registry of Acute Coronary Events (GRACE) score and NT-proBNP are added to multivariate models. Early postinfarction levels of ST2 (i.e., <24 hours after admission) have the greatest prognostic utility. Early postinfarction ST2 levels and change over 24 weeks are related to infarct extent and remodeling to a similar extent as NT-proBNP and aldosterone, and ST2 may have a significant pathophysiological role in these postinfarction processes. In long-term follow-up of stable IHD, ST2 is predictive of all-cause and cardiovascular mortality independent of accepted clinical indicators and other biomarkers, including NT-proBNP, high-sensitivity C-reactive protein, interleukin-6, high-sensitivitiy cardiac troponin T, and galectin-3. In conclusion, ST2 in combination with NT-proBNP consistently improves risk stratification compared with either marker alone