Three-Dimensional Dynamic Behavior of Embankment on Liquefiable Ground

In recent years, there has been serious damage to embankments on liquefied ground because of large earthquakes. To understand such damage, many two-dimensional shaking table model tests have been performed, in both gravitational and centrifugal fields, to investigate the dynamic behavior and residual displacement of embankments and river dikes on liquefiable ground. In recent years, three-dimensional numerical analysis has been used in practical design because it is difficult to consider the complex dynamic behaviors of three-dimensional embankments and the surrounding liquefied ground in a two-dimensional analysis. However, there are only a limited number of cases in which the applicability of three-dimensional analysis has been validated based on comparisons with true values derived from model tests or data from actual disasters. Therefore, in this study, a series of shaking table tests were conducted to investigate the seismic behavior of a three-dimensional embankment on liquefiable ground. In addition, the effect of the shaking direction on the seismic behavior of the embankment was evaluated. The experiment revealed that the residual deformation and its dominant direction were significantly affected by the three-dimensional shape and total weight of the embankment, not by the shaking direction. This result indicates that the influence of the three-dimensional shape of the embankment on the deformation behavior cannot be ignored, and that the influence should be properly evaluated in seismic design.

Non-adiabatic modulation of premixed-flame thermoacoustic frequencies in slender tubes

This paper presents an experimental study of the influence of heat losses on the onset of thermoacoustic instabilities in methane–air premixed flames propagating in a horizontal tube of diameter, $D = 10$ mm. Flames are ignited at the open end of the tube and propagate towards the closed end undergoing strong oscillations of different features owing to the interaction with acoustic waves. The frequency of oscillation and its axial location are controlled through the tube length $L$ and the intensity of heat losses. These parameters are respectively modified in the experiments by a moveable piston and a circulating thermal bath of water prescribing temperature conditions. Main experimental observations show that classical one-dimensional predictions of the oscillation frequency do not accurately describe the phenomena under non-adiabatic real scenarios. In addition to the experimental measurements, a quasi-one-dimensional analysis of the burnt gases is provided, which introduces the effect of heat losses at the wall of the tube on the interplay between the acoustic field and the reaction sheet. As a result, this analysis provides an improved description of the interaction and accurately predicts the excited flame-oscillation harmonics through the eigenvalues of the non-adiabatic acoustics model. Unlike the original one-dimensional analysis, the comparison between the flame oscillation frequency provided by the non-adiabatic extended theory and the frequencies measured in our experiments is in excellent agreement in the whole range of temperatures considered. This confirms the importance of heat losses in the modulation of the instabilities and the transition between different flame oscillation regimes.

Binding without variables: Solving the under-generation problems

The variable-free semantics of Jacobson (1999, 2000, 2014) derives binding relations by the local application of the z-rule. This rule, however, under- generates binding. This paper makes two contributions: (i) replacing the z-rule with a more flexible rule called i (a la the W-combinator of Szabolcsi 1992), which allows for more binding relations; (ii) enriching Jacobson’s variable-free system and proposing a two-dimensional analysis to account for the interactions between scoping and binding. Issues to be covered include binding into adjuncts, possessor binding, scope ambiguity, inverse linking, weak crossover, and ‘paycheck pronouns’.

Experimental investigations on nucleate pool boiling over micro-finned cylindrical surfaces

The nucleate pool boiling heat transfer over micro-finned cylindrical surfaces has application in the heat exchangers used in thermal power plants and chemical industries. The estimation of boiling heat transfer coefficient is an important parameter in the design of two-phase heat exchangers using micro-finned cylindrical surfaces. In the present work, related experimental investigations on four micro-finned cylindrical surfaces with different surface geometry using refrigerant R-141b at atmospheric pressure are conducted to determine the boiling heat transfer coefficient over micro-finned cylindrical surfaces. A correlation is developed by dimensional analysis wherein the effects of geometrical parameters, operating pressure and thermo-physical properties of fluids are taken into consideration and dimensional analysis conducted using Buckingham π-theorem. The correlation developed utilizes experimental data obtained over the present study as well as from previous studies by various researchers including experimental data for water over different micro-finned cylindrical surfaces at 1 bar by Mehta and Kandlikar, experimental data for R123 at 0.97 bar by Saidi et al. and experimental data for R134a over micro-finned cylindrical surface at 6.1 bar, 8.1 bar, 10.1 bar and 12.2 bar by Rocha et al. The heat flux ranging from 5 to 1100 kW/m2 are considered for the analysis. The data points have been compared with the proposed correlation and the absolute average deviation of the whole data set was obtained as 13.43% with root mean square deviation of 0.0273. All the predicted values were within ±15% of the experimental values of the boiling heat transfer coefficient.