Inverse perturbation method for structural redesign with frequency and mode shape constraints

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76581/1/AIAA-8777-705.pd

Nonlinear incremental inverse perturbation method for structural redesign

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76715/1/AIAA-1983-892-392.pd

Happier People Live More Active Lives: Using Smartphones to Link Happiness and Physical Activity.

Physical activity, both exercise and non-exercise, has far-reaching benefits to physical health. Although exercise has also been linked to psychological health (e.g., happiness), little research has examined physical activity more broadly, taking into account non-exercise activity as well as exercise. We examined the relationship between physical activity (measured broadly) and happiness using a smartphone application. This app has collected self-reports of happiness and physical activity from over ten thousand participants, while passively gathering information about physical activity from the accelerometers on users' phones. The findings reveal that individuals who are more physically active are happier. Further, individuals are happier in the moments when they are more physically active. These results emerged when assessing activity subjectively, via self-report, or objectively, via participants' smartphone accelerometers. Overall, this research suggests that not only exercise but also non-exercise physical activity is related to happiness. This research further demonstrates how smartphones can be used to collect large-scale data to examine psychological, behavioral, and health-related phenomena as they naturally occur in everyday life.Engineering and Physical Sciences Research Council (UBhave project (Ubiquitous and Social Computing for Positive Behaviour Change, Grant ID: EP/I032673/1))This is the final version of the article. It first appeared from Public Library of Science via https://doi.org/http://dx.doi.org/10.1371/journal.pone.016058

Admissible large perturbations in structural redesign

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76363/1/AIAA-10551-828.pd

A Parallactic Distance of 389 +24/-21 parsecs to the Orion Nebula Cluster from Very Long Baseline Array Observations

We determine the parallax and proper motion of the flaring, non-thermal radio star GMR A, a member of the Orion Nebula Cluster, using Very Long Baseline Array observations. Based on the parallax, we measure a distance of 389 +24/-21 parsecs to the source. Our measurement places the Orion Nebula Cluster considerably closer than the canonical distance of 480 +/- 80 parsecs determined by Genzel et al. (1981). A change of this magnitude in distance lowers the luminosities of the stars in the cluster by a factor of ~ 1.5. We briefly discuss two effects of this change--an increase in the age spread of the pre-main sequence stars and better agreement between the zero-age main-sequence and the temperatures and luminosities of massive stars.Comment: 10 pages, 4 figures, emulateapj, accepted to Ap

Dusty OB stars in the Small Magellanic Cloud - II: Extragalactic Disks or Examples of the Pleiades Phenomenon?

We use mid-infrared Spitzer spectroscopy and far-infrared Herschel photometry for a sample of twenty main sequence O9--B2 stars in the Small Magellanic Cloud (SMC) with strong 24 micron excesses to investigate the origin of the mid-IR emission. Either debris disks around the stars or illuminated patches of dense interstellar medium (ISM) can cause such mid-IR emission. In a companion paper, Paper I, we use optical spectroscopy to show that it is unlikely for any of these sources to be classical Be stars or Herbig Ae/Be stars. We focus our analysis on debris disks and cirrus hot spots. We find three out of twenty stars to be significantly extended in the mid-IR, establishing them as cirrus hot spots. We then fit the IR spectral energy distributions to determine dust temperatures and masses. We find the dust masses in the SMC stars to be larger than for any known debris disks, although this evidence against the debris disk hypothesis is circumstantial. Finally, we created a local comparison sample of bright mid-IR OB stars in the Milky Way (MW) by cross-matching the WISE and Hipparcos catalogs. All such local stars in the appropriate luminosity range that can be unambiguously classified are young stars with optical emission lines or are spatially resolved by WISE with sizes too large to be plausible debris disk candidates. We conclude that the very strong mid-IR flux excesses are most likely explained as cirrus hot spots, although we cannot rigorously rule out that a small fraction of the sample is made up of debris disks or transition disks. We present suggestive evidence that bow-shock heating around runaway stars may be a contributing mechanism to the interstellar emission. These sources, interpreted as cirrus hot spots, offer a new localised probe of diffuse interstellar dust in a low metallicity environment. (Abridged)Comment: Accepted for publication in ApJ, 23 pages, 11 figures, 8 table

Metamaterials for light rays: ray optics without wave-optical analog in the ray-optics limit

Volumes of sub-wavelength electromagnetic elements can act like homogeneous materials: metamaterials. In analogy, sheets of optical elements such as prisms can act ray-optically like homogeneous sheet materials. In this sense, such sheets can be considered to be metamaterials for light rays (METATOYs). METATOYs realize new and unusual transformations of the directions of transmitted light rays. We study here, in the ray-optics and scalar-wave limits, the wave-optical analog of such transformations, and we show that such an analog does not always exist. Perhaps, this is the reason why many of the ray-optical possibilities offered by METATOYs have never before been considered.Comment: 10 pages, 3 figures, references update