Visualization of flows in a motored rotary combustion engine using holographic interferometry

The use of holographic interferometry to view the small- and large-scale flow field structures in the combustion chamber of a motored Wankel engine assembly is described. In order that the flow patterns of interest could be observed, small quantities of helium were injected with the intake air. Variation of the air flow patterns with engine speed, helium flow rate, and rotor position are described. The air flow at two locations within the combustion chamber was examined using this technique

Automated monitoring of urination events from grazing cattle

AbstractUrine patches deposited by grazing cattle represent ‘hot-spots’ of very high nitrogen (N) loading from which environmentally important losses of N may occur (ammonia and nitrous oxide emissions, nitrate leaching). Information on the quantities of N deposited to grazed pastures as urine, the spatial and temporal distribution of urine patches and how these may be influenced by pasture management practices is limited. The objectives of this study were to assess the potential of recently developed urine sensors for providing data on urination behaviour by grazing cattle and relate this to measurements of ammonia emissions from the grazed paddocks. A total of six trials were conducted across two sites; two on a 1ha paddock at Easter Bush near Edinburgh using beef cattle (c. 630kg live weight) and four on a 0.5ha paddock at North Wyke in Devon using in-calf dairy heifers (c. 450kg live weight). Laboratory calibrations were conducted to provide sensor-specific functions for urine volume and N concentration. The quantity and quality of data from the urine sensors improved with successive trials through modifications to the method of attachment to the cow. The number of urination events per animal per day was greater for the dairy heifers, with a mean value of 11.6 (se 0.70) compared with 7.6 (se 0.76) for the beef cattle. Volume per urination event (mean 1.8, range 0.4–6.4L) and urine N concentration (range 0.6–31.5gL−1, excluding outliers) were similar for the two groups of cattle. Ammonia emission measurements were unsuccessful in most of the trials. The urine sensors have potential to provide useful information on urine N deposition by grazing cattle but suggested improvements including making the sensors lighter, designing a better method of attachment to the cow and including a more reliable location sensor

Physics, Astrophysics and Cosmology with Gravitational Waves

Gravitational wave detectors are already operating at interesting sensitivity levels, and they have an upgrade path that should result in secure detections by 2014. We review the physics of gravitational waves, how they interact with detectors (bars and interferometers), and how these detectors operate. We study the most likely sources of gravitational waves and review the data analysis methods that are used to extract their signals from detector noise. Then we consider the consequences of gravitational wave detections and observations for physics, astrophysics, and cosmology.Comment: 137 pages, 16 figures, Published version <http://www.livingreviews.org/lrr-2009-2