Mie scattering from a sonoluminescing air bubble in water

Applied Optics, Volume 34, No. 15, pp. 2648-2654 (20 May 1995)A single bubble of air in water can emit pulses of blue-white light that have durations of less than 50 ps while it is oscillating in an acoustic standing wave. The emission is called sonoluminescence. A knowledge of the bubble diameter throughout the cycle, and in particular near the time of sonoluminescence emission, can provide important information about the phenomenon. A new Mie scattering technique is developed to determine the size of the bubble through its expansion and collapse during the acoustic cycle. The technique does not rely on an independent means of calibration or on accurate measurements of the scattered intensity.This work was supported in part by the Naval Postgraduate School Research Program and the Office of Naval Research

Genetic properties of feed efficiency parameters in meat-type chickens

<p>Abstract</p> <p>Background</p> <p>Feed cost constitutes about 70% of the cost of raising broilers, but the efficiency of feed utilization has not kept up the growth potential of today's broilers. Improvement in feed efficiency would reduce the amount of feed required for growth, the production cost and the amount of nitrogenous waste. We studied residual feed intake (RFI) and feed conversion ratio (FCR) over two age periods to delineate their genetic inter-relationships.</p> <p>Methods</p> <p>We used an animal model combined with Gibb sampling to estimate genetic parameters in a pedigreed random mating broiler control population.</p> <p>Results</p> <p>Heritability of RFI and FCR was 0.42-0.45. Thus selection on RFI was expected to improve feed efficiency and subsequently reduce feed intake (FI). Whereas the genetic correlation between RFI and body weight gain (BWG) at days 28-35 was moderately positive, it was negligible at days 35-42. Therefore, the timing of selection for RFI will influence the expected response. Selection for improved RFI at days 28-35 will reduce FI, but also increase growth rate. However, selection for improved RFI at days 35-42 will reduce FI without any significant change in growth rate. The nature of the pleiotropic relationship between RFI and FCR may be dependent on age, and consequently the molecular factors that govern RFI and FCR may also depend on stage of development, or on the nature of resource allocation of FI above maintenance directed towards protein accretion and fat deposition. The insignificant genetic correlation between RFI and BWG at days 35-42 demonstrates the independence of RFI on the level of production, thereby making it possible to study the molecular, physiological and nutrient digestibility mechanisms underlying RFI without the confounding effects of growth. The heritability estimate of FCR was 0.49 and 0.41 for days 28-35 and days 35-42, respectively.</p> <p>Conclusion</p> <p>Selection for FCR will improve efficiency of feed utilization but because of the genetic dependence of FCR and its components, selection based on FCR will reduce FI and increase growth rate. However, the correlated responses in both FI and BWG cannot be predicted accurately because of the inherent problem of FCR being a ratio trait.</p

Is Sonoluminescence due to Collision-Induced Emission?

We estimate the collision-induced emission (CIE) intensity and profile in the visible and near UV region of the spectrum of N2-X pairs, where X represents another N2molecule or an argon atom, etc. of shock waves believed to exist in sonoluminescence experiments. Calculated profiles consist of superimposed high overtone bands and resemble the measured profiles. Intensities calculated on the basis of a few, simple assumptions concerning the induced dipole surface compare favorably with measurements. The agreement obtained suggests that CIE is an attractive alternative to bremsstrahlung to explain sonoluminescence. The CIE source is optically thin, and the spectral emission profile is not related to Planck's law.University of TexasApplied Research Laboratorie

Basic Research in Thermoacoustic Heat Transport

Annual rept. 1 Jun 95-31 May 96This technical report details progress in basic research in thermoacoustic heat transport made during the period June 1, 1995 through May 30, 1996. Research efforts were primarily concentrated in three areas: 1) investigation of fundamental limitations to the performance of thermoacoustic devices; 2) design, construction, and demonstration of a proof-of-concept, shipboard, heat driven thermoacoustic cooler capable of cooling loads of 1 kW; 3) measurement of transient effects in thermoacoustic devices to provide data to test nonlinear, timedependent models of thermoacoustics. Accomplishments include 1) the design of a prototype toroidal prime mover; 2) preliminary measurements of the temperature evolution along a stack in a mechanically driven configuration; 3) preliminary measurements of transient effects in prime movers; 4) preliminary design of a new prime mover configuration; and 5) fabrication of a 1 kVV heat driven cooler. A publications, patents, presentations, and honors report is also included.Office of Naval Research, ONR 331, 800 North Quincy Street, Arlington, VA 22217-5660PE61153NN0001496VVR20004N0001496AF00002Approved for public release; distribution is unlimited.Approved for public release; distribution is unlimited

Chaotic sonoluminescence

Sonoluminescence (SL) is generated from single, stably oscillating bubbles in a stationary, time-periodic acoustic field. By measuring the time delay between flashes, the dynamics of the phenomenon has been investigated. While other researchers have concentrated on the remarkable periodic stability of the system, present results indicate that, for small variations in the governing parameters, period doubling, chaos, and quasiperiodicity can occur. The implications of the complex temporal behavior for the problem of determining the mechanism(s) for production of SL are discussed.Work was done with partial support from NASA, Office of Naval Research and the Naval Postgraduate School research program, and Deutsche ForschungsgemeinscchaftApproved for public release; distribution is unlimited

Spectra of single-bubble sonoluminescence in water and glycerin-water mixtures

A single gas bubble, acoustically levitated in a standing-wave field and oscillating under the action of that field, can emit pulses of blue-white light with duration less than 50 ps. Measurements of the spectrum of this picosecond sonoluminescence with a scanning monochrometer are reported for air bubbles levitated in water and in glycerin-water mixtures. While the spectrum has been reported previously by others for air bubbles in water, the spectrum for air bubbles in water-glycerin mixtures has not. Expected emission lines from glycerin were conspicuously absent, suggesting a different mechanism for light production in single-bubble sonoluminescence. Other conclusions are the spectrum for air bubbles in water is consistent with that previously reported, the radiated energy decreases as the glycerin concentration increases, and the peak of the spectrum appears to shift to longer wavelengths for the water-glycerin mixtures.This work was supported in part by the Office of Naval Research, the Defense Nuclear Agency, and the Naval Postgraduate School Research Program. The authors wish to thank David Cleary for the use of the scanning monochrometer and D. Scott Davis for many helpful discussions