Numerical investigation of the Earth's rotation during a complete precession cycle

A theory for the long-term rotational motion of the quasi-rigid Earth was constructed by numerical integration. The theory spans 72,000 years centered about 1968 A.D., and provides accurate rotational and positional data for the Earth in the recent past and the near future. The physical model is termed dynamically consistent because developments for the active forces and torques are truncated based solely on their magnitudes regardless of their origin. The model includes all appropriate forces and torques due to the geopotential and tidal effects as well as lunisolar and planetary contributions. The elastic and inelastic deformations due to tidal action were too small to affect the mass properties of the Earth at the truncation level of the model. However, long-term dissipative effects of the tidal forces and torques were not negligible. These considerations gave the model its quasi-rigid characterization. The numerical output provided both rotational and orbital-element data. The data were fitted throughout the 72,000-year range using Chebyshev polynomial series

The pitch-heave dynamics of transportation vehicles

The analysis and design of suspensions for vehicles of finite length using pitch-heave models is presented. Dynamic models for the finite length vehicle include the spatial distribution of the guideway input disturbance over the vehicle length, as well as both pitch and heave degrees-of-freedom. Analytical results relate the vehicle front and rear accelerations to the pitch and heave natural frequencies, which are functions of vehicle suspension geometry and mass distribution. The effects of vehicle asymmetry and suspension contact area are evaluated. Design guidelines are presented for the modification of vehicle and suspension parameters to meet alternative ride quality criteria

Tungsten thermal neutron dosimeter

Tungsten-185 activity, which is produced by neutron activation of tungsten-184, determines thermal neutron flux. Radiochemical separation methods and counting techniques for irradiated tungsten provide accurate determination of the radiation exposure

Integrating multiple representations: fighting asthma

This paper seeks to engage debates about integrating pluralisms regarding multiple forms/representations and how they might function smoothly if they are closely aligned. This paper offers, narrative poetry with an artistic impression aimed at seeing how these might interact with each other. Like poetry, visual images are unique and can evoke particular kinds of emotional and visceral responses. By offering narrative poetry together with an artistic representation it is not meant to de-value the importance of either, but it is aimed at seeing how these arts-based methods and creative analytical practices might unite as a narrative to offer knew ways of ‘knowing’ and ‘seeing

3.8-Micron Photometry During the Secondary Eclipse of the Extrasolar Planet HD 209458b

We report infrared photometry of the extrasolar planet HD 209458b during the time of secondary eclipse (planet passing behind the star). Observations were acquired during two secondary eclipses at the NASA Infrared Telescope Facility (IRTF) in September 2003. We used a circular variable filter (1.5-percent bandpass) centered at 3.8 microns to isolate the predicted flux peak of the planet at this wavelength. Residual telluric absorption and instrument variations were removed by offsetting the telescope to nearby bright comparison stars at a high temporal cadence. Our results give a secondary eclipse depth of 0.0013 +/- 0.0011, not yet sufficient precision to detect the eclipse, whose expected depth is approximately 0.002 - 0.003. We here elucidate the current observational limitations to this technique, and discuss the approach needed to achieve detections of hot Jupiter secondary eclipses at 3.8 microns from the ground.Comment: 5 pages, 5 figures, in press for MNRA