The solid state photomultiplier: Status of photon counting beyond the near-infrared

Rockwell International's Solid State Photomultiplier (SSPM) is an impurity-band avalanche device which can count individual photons with wavelengths between 0.4 and 28 micrometers. Its response to a photon is a pulse of between 10(exp 4) and 10(exp 5) conduction electrons, making it an important device for use in phenomenology. The characteristics of the SSPM make it a potentially important device for use in astronomical applications. Contract NAS2-12400 was initiated in June 1986 to conduct modeling and characterization studies of the SSPM to provide a basis for assessing its use in astronomical systems. Some SSPM models and results of measurements which characterize the group of SSPMs recently fabricated on this contract are discussed

Solution to the problem of the poor cyclic fatigue resistance of bulk metallic glasses

The recent development of metallic glass-matrix composites represents a particular milestone in engineering materials for structural applications owing to their remarkable combination of strength and toughness. However, metallic glasses are highly susceptible to cyclic fatigue damage, and previous attempts to solve this problem have been largely disappointing. Here, we propose and demonstrate a microstructural design strategy to overcome this limitation by matching the microstructural length scales (of the second phase) to mechanical crack-length scales. Specifically, semisolid processing is used to optimize the volume fraction, morphology, and size of second-phase dendrites to confine any initial deformation (shear banding) to the glassy regions separating dendrite arms having length scales of ≈2 μm, i.e., to less than the critical crack size for failure. Confinement of the damage to such interdendritic regions results in enhancement of fatigue lifetimes and increases the fatigue limit by an order of magnitude, making these “designed” composites as resistant to fatigue damage as high-strength steels and aluminum alloys. These design strategies can be universally applied to any other metallic glass systems

Observations of the 5‐day wave in the mesosphere and lower thermosphere

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94851/1/grl7954.pd

TIMED Doppler Interferometer on the Thermosphere Ionosphere Mesosphere Energetics and Dynamics satellite: Data product overview

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94699/1/jgra18252.pd

Use of PCR to identify Leptospira in kidneys of big brown bats (Eptesicus fuscus) in Kansas and Nebraska, USA

Bats have been implicated as potential carriers of Leptospira as a result of surveys, mostly in Australia and South America. We measured the prevalence of pathogenic leptospires in kidneys of bats from Kansas and Nebraska. From 7 August 2012 to 21 August 2012, we extracted DNA from kidneys of 98 big brown bats (Eptesicus fuscus) submitted and found negative for rabies. The DNA was processed in a two-step, seminested PCR assay with a dual-labeled Taqman probe specific for pathogenic leptospires. As a negative control, we used a saprophytic leptospire (Leptospira biflexa Patoc) and, as a pathogenic control, Leptospira interrogans Canicola. All bat kidneys were negative for pathogenic leptospires, suggesting that it is unlikely that the big brown bat, one of the most prevalent bat species in North America, is a reservoir for transmission of leptospires to dogs or humans

Atmospheric wind measurements with the high-resolution Doppler imager

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76745/1/AIAA-26590-119.pd

Observations of the quasi 2‐day wave from the High Resolution Doppler Imager on Uars

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95387/1/grl7238.pd