The development and mitigation of backdraft: a real-scale shipboard study

This paper presents the results of a real-scale experimental test series to study the development and mitigation of backdrafts. Experiments consisted of creating backdrafts onboard a US Navy test ship, ex-USS SHADWELL. This study has shown that the key parameter for backdraft development is the fuel mass fraction. The results show that the critical fuel mass fraction, Y_f, required for the development of diesel fuel backdraft is 0.16 for fully vitiated conditions. The effects of varying adjacent room boundaries and ventilation conditions are discussed. In general, the intensity of a backdraft is more dependent on the adjacent boundaries than on the ventilation conditions. The injection of water spray into the fire compartment was shown to be an effective mitigating tactic that was able to completely suppress backdrafts primarily by means of diluting the atmosphere and reducing the fuel mass fraction, rather than by a thermal mechanism of cooling.     

Opening remarks and the power spectrum of ocean waves

The Fourier spectrum of waves in the Pacific Ocean is analysed. The power in 4?s waves is more regular than the power in 10?s waves and larger than expected.     

Laboratory testing the Anaconda

Laboratory measurements of the performance of the Anaconda are presented, a wave energy converter comprising a submerged water-filled distensible tube aligned with the incident waves. Experiments were carried out at a scale of around 1:25 with a 250 mm diameter and 7 m long tube, constructed of rubber and fabric, terminating in a linear power take-off of adjustable impedance. The paper presents some basic theory that leads to predictions of distensibility and bulge wave speed in a pressurized compound rubber and fabric tube, including the effects of inelastic sectors in the circumference, longitudinal tension and the surrounding fluid. Results are shown to agree closely with measurements in still water. The theory is developed further to provide a model for the propagation of bulges and power conversion in the Anaconda. In the presence of external water waves, the theory identifies three distinct internal wave components and provides theoretical estimates of power capture. For the first time, these and other predictions of the behaviour of the Anaconda, a device unlike almost all other marine systems, are shown to be in remarkably close agreement with measurements.     

Obituary: Hans J. Eysenck (1916–1997).

Memorializes H. J. Eysenck, who, before his death, was the world's most cited psychologist. Eysenck wrote on topics ranging from animal behavior genetics to the psychology of political behavior and the possibilities of parapsychology. Eysenck is remembered for his measurement-based personality research, identification of personality dimensions, connection of personality to health, scientific approaches to therapy and to clinical psychology in general, contributions to human intelligence, and popularization of psychology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Temporal location of unsignaled food deliveries: Effects on conditioned withdrawal (inhibition) in pigeon signtracking.

Standard models of Pavlovian conditioning neglect local effects of unsignaled unconditioned stimuli (USs) on learning and performance. Using the approach-withdrawal behavior of pigeons toward keylights as conditioned stimuli (CSs), the authors varied the specific times (5–210 s) that USs occurred before or after a CS. Withdrawal from a CS generally increased as the time between a US before and/or after the CS was lengthened. Combinations of 2 distant USs produced more withdrawal from the CS than either US alone, whereas combinations of a distant and a nearby US yielded behavior intermediate between that for either US alone. Postacquisition retardation tests supported similar conclusions. Based on the temporal isolation of CSs and USs, a tentative model was offered to summarize these data. The results and the model suggest that a more molecular, possibly perceptual approach to Pavlovian excitation and inhibition is needed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The elastic properties of lithium oxide and their variation with temperature

The energies of the acoustic phonon modes in a single crystal of ⁷Li₂O have been measured in the temperature range 293–1603 K using the technique of inelastic neutron scattering. The slopes of the phonon energy dispersion curves as they approach the Brillouin zone centre give values for the cubic elastic stiffness constants, C_ij. C₁₁ is found to undergo a sharp decrease above ˜ 1350 K similar to that observed in structurally related compounds, such as CaF₂ and SrCl₂, as they undergo a transition to a fast-ion phase. The Reuss and Voigt averaging methods have been used to calculate the temperature dependence of the adiabatic Young's modulus, shear modulus, bulk modulus and Poisson's ratio of polycrystalline Li₂O. Estimates of the corresponding isothermal values are obtained using an expression for the linear thermal expansion coefficient of Li₂O obtained in this work, together with thermodynamic data available from specific heat measurements. These results represent the first experimental data describing the elastic properties of Li₂O at elevated temperatures and are important in predicting the behaviour of this material in its potential role as a tritium breeding blanket material for future fusion reactors.