Evaluation of directionally solidified eutectic superalloys for turbine blade applications

Alloys from the following systems were selected for property evaluation: (1) gamma/gamma-Mo (Ni-base, rods of Mo); (2) gamma-beta (Ni-base, lamellae or rods of (Ni, Fe/Co Al); and (3) gamma-gamma (Ni-base rods of Ni3Al gamma). The three alloys were subjected to longitudinal and transverse tensile and rupture tests from 750 C to 1100 C, longitudinal shear strength was measured at several temperatures, resistance to thermal cycling to 1150 C was determined, cyclic oxidation resistance was evaluated at 750 C and 1100 C, and each system was directionally solidified in an alumina shell mold turbine shape to evaluate mold/metal reactivity. The gamma/gamma Mo system has good rupture resistance, transverse properties and processability, and is a high potential system for turbine blades. The gamma-beta system has good physical properties and oxidation resistance, and is a potential system for turbine vanes. The gamma-gamma system has good high temperature rupture resistance and requires further exploratory research

Mantle devolatilization and convection: Implications for the thermal history of the Earth

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95357/1/grl3652.pd

Parallel Evolution in the Integration of a Co-obligate Aphid Symbiosis

Dependence on multiple nutrient- provisioning symbionts has evolved numerous times in insects. Monnin et al. provide evidence from the symbionts of aphids that these dependencies evolve in a predictable manner. The repeated losses of the same metabolic pathways bind the symbionts into co-dependence, and integration follows in a stepwise manner

Interferometric imaging of the sulfur-bearing molecules H2S, SO and CS in comet C/1995 O1 (Hale-Bopp)

We present observations of rotational lines of H2S, SO and CS performed in comet C/1995 O1 (Hale-Bopp) in March 1997 with the Plateau de Bure interferometer (IRAM). The observations provide informations on the spatial and velocity distributions of these molecules. They can be used to constrain their photodissociation rate and their origin. We use a radiative transfer code which allows us to compute synthetic line profiles and interferometric maps, to be compared to the observations. Both single-dish spectra and interferometric spectral maps show a day/night asymmetry in the outgassing. From the analysis of the spectral maps, including the astrometry, we show that SO and CS present in addition a jet-like structure that may be the gaseous counterpart of the dust high-latitude jet observed in optical images. A CS rotating jet is also observed. Using the astrometry provided by continuum radio maps obtained in parallel, we conclude that there is no need to invoke of nongravitational forces acting on this comet, and provide an updated orbit. The radial extension of H2S is found to be consistent with direct release from the nucleus. SO displays an extended radial distribution. Assuming that SO2 is the parent of SO, the photodissociation rate of SO is measured to be 1.5 E-4 s-1 at 1 AU from the Sun. This is lower than most laboratory-based estimates and may suggest that SO is not solely produced by SO2 photolysis. From the observations of J(2-1) and J(5-4) CS lines, we deduce a CS photodissociation rate of 1 to 5 E-5 s-1. The photodissociation rate of CS2, the likely parent of CS, cannot be constrained due to insufficient resolution, but our data are consistent with published values. These observations illustrate the cometary science that will be performed with the future ALMA interferometer.Comment: Accepted for publication in Astronomy & Astrophysic

Tobacco smoking predicts depression and poorer quality of life in heart disease

BACKGROUND: We report on the prospective association between smoking and depression and health-related quality of life (HRQOL) in patients with coronary artery disease (CAD). METHODS: Prospective study of 193 patients with assessment of depression occurring 3-, 6- and 9- months (T1, 2, and 3, respectively) following discharge from hospital for a cardiac event. HRQOL was assessed at T3. T1 depression was assessed by clinical interview; T2 and T3 depression was assessed by self-report. Smoking at time of cardiac event was assessed by self-report. Multivariate analyses controlled for known demographic, psychosocial and clinical correlates of depression. RESULTS: Smoking at the time of index cardiac event increased the likelihood of being diagnosed with Major Depressive Disorder (MDD) at T1 by 4.30 [95% CI, 1.12-16.46; p < .05]. The likelihood of receiving a diagnosis of minor depression, dysthymia or MDD as a combined group was increased by 8.03 [95% CI, 2.35-27.46; p < .01]. Smoking did not reliably predict depression at T2 or T3 and did not reliably predict persistent depression. Smoking increased the likelihood of being classified as depressed according to study criteria at least once during the study period by 5.19 [95% CI, 1.51-17.82; p < .01]. Smoking independently predicted worse mental HRQOL. CONCLUSIONS: The findings support a role for smoking as an independent predictor of depression in CAD patients, particularly in the first 3 months post-cardiac event. The well-established imperative to encourage smoking cessation in these patients is augmented and the findings may add to the evidence for smoking cessation campaigns in the primary prevention of depression

Bordetella petrii Clinical Isolate

We describe the first clinical isolate of Bordetella petrii from a patient with mandibular osteomyelitis. The only previously documented isolation of B. petrii occurred after the initial culture of a single strain from an environmental source

Symbioses shape feeding niches and diversification across insects.

For over 300 million years, insects have relied on symbiotic microbes for nutrition and defence. However, it is unclear whether specific ecological conditions have repeatedly favoured the evolution of symbioses, and how this has influenced insect diversification. Here, using data on 1,850 microbe-insect symbioses across 402 insect families, we found that symbionts have allowed insects to specialize on a range of nutrient-imbalanced diets, including phloem, blood and wood. Across diets, the only limiting nutrient consistently associated with the evolution of obligate symbiosis was B vitamins. The shift to new diets, facilitated by symbionts, had mixed consequences for insect diversification. In some cases, such as herbivory, it resulted in spectacular species proliferation. In other niches, such as strict blood feeding, diversification has been severely constrained. Symbioses therefore appear to solve widespread nutrient deficiencies for insects, but the consequences for insect diversification depend on the feeding niche that is invaded

Brief of Corporate Law Professors as Amici Curie in Support of Respondents

The Supreme Court has looked to the rights of corporate shareholders in determining the rights of union members and non-members to control political spending, and vice versa. The Court sometimes assumes that if shareholders disapprove of corporate political expression, they can easily sell their shares or exercise control over corporate spending. This assumption is mistaken. Because of how capital is saved and invested, most individual shareholders cannot obtain full information about corporate political activities, even after the fact, nor can they prevent their savings from being used to speak in ways with which they disagree. Individual shareholders have no “opt out” rights or practical ability to avoid subsidizing corporate political expression with which they disagree. Nor do individuals have the practical option to refrain from putting their savings into equity investments, as doing so would impose damaging economic penalties and ignore conventional financial guidance for individual investors

Spherical harmonic representation of the gravitational potential of discrete spherical mass elements

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73812/1/j.1365-246X.1991.tb01157.x.pd