Closure to ＂Discussion on ＇Optimum placement and characteristics of velocity-dependent dampers under seismic excitation＇ by SA Mousavi and AK Ghorbani-Tanha＂ by Izuru Takewaki

The authors would like to thank the discusser for his considerations and comments. The discusser believes that some of the derived formulations need to be referred to his previously published works and also some related studies have not been cited.     

Investigating the time dynamics of monthly rainfall time series observed in northern Lebanon by means of the detrended fluctuation analysis and the Fisher-Shannon method

We investigate the time dynamics of monthly rainfall series intermittently recorded on seven climatic stations in northern Lebanon from 1939 to 2010 using the detrending fluctuation analysis (DFA) and the Fisher-Shannon (FS) method. The DFA is employed to study the scaling properties of the series, while the FS method to analyze their order/organization structure. The obtained results indicate that most all the stations show a significant persistent behavior, suggesting that the dynamics of the rainfall series is governed by positive feedback mechanisms. Furthermore, we found that the Fisher Information Measure (the Shannon entropy power) seems to decrease (increase) with the height of the rain gauge; this indicates that the rainfall series appear less organized and less regular for higher-located stations. Such findings could be useful for a better comprehension of the climatic regimes governing northern Lebanon.     

Growing electrostatic modes in the isothermal pair plasma of the pulsar magnetosphere

It is shown that a strongly magnetized isothermal pair plasma near the surface of a pulsar supports low-frequency (in comparison to electron cyclotron frequency) toroidal electrostatic plasma modes in the equatorial region. Physically, the thermal pressure coupled with the magnetic pressure creates the low frequency oscillations which may grow for particular case of inhomogeneities of the equilibrium magnetic field and the pair plasma density.     

Adaptive multi‐rate interface: development and experimental verification for real‐time hybrid simulation

Real‐time hybrid simulation (RTHS) is a powerful cyber‐physical technique that is a relatively cost‐effective method to perform global/local system evaluation of structural systems. A major factor that determines the ability of an RTHS to represent true system‐level behavior is the fidelity of the numerical substructure. While the use of higher‐order models increases fidelity of the simulation, it also increases the demand for computational resources. Because RTHS is executed at real‐time, in a conventional RTHS configuration, this increase in computational resources may limit the achievable sampling frequencies and/or introduce delays that can degrade its stability and performance. In this study, the Adaptive Multi‐rate Interface rate‐transitioning and compensation technique is developed to enable the use of more complex numerical models. Such a multi‐rate RTHS is strictly executed at real‐time, although it employs different time steps in the numerical and the physical substructures while including rate‐transitioning to link the components appropriately. Typically, a higher‐order numerical substructure model is solved at larger time intervals, and is coupled with a physical substructure that is driven at smaller time intervals for actuator control purposes. Through a series of simulations, the performance of the AMRI and several existing approaches for multi‐rate RTHS is compared. It is noted that compared with existing methods, AMRI leads to a smaller error, especially at higher ratios of sampling frequency between the numerical and physical substructures and for input signals with high‐frequency content. Further, it does not induce signal chattering at the coupling frequency. The effectiveness of AMRI is also verified experimentally. Copyright © 2016 John Wiley & Sons, Ltd.     

Analysis of long-term fluctuations in stream flow time series: An application to Litani River, Lebanon

Litani River is the largest river in Lebanon and has been affected by several physical and anthropogenic factors that influenced its flow dynamics. By means of the Singular Spectrum Analysis (SSA), the time dynamics of the stream flow of seven sites along the course of Litani River was investigated, extracting for each site the long-term trend. A clear decreasing trend characterizes all the long-term trends of the stream flow. Furthermore, several peaks were identified, consistent with the rainfall rate and snow cover variability.     

Experimental study on the phase transformation point of crushable and noncrushable soils

Two marine calcareous deposits as crushable soils and a siliceous sand as a noncrushable soil were used in this study to compare their monotonic response. Undrained monotonic triaxial tests were conducted on samples, which were prepared in different relative densities and consolidated under various confining pressures. The location of phase transformation point in undrained response of the sands in different initial conditions was evaluated. The effect of important parameters including relative density, confining pressure, particle shape, and particle breakage on phase transformation point was assessed. The input energy applied per unit volume of the soils was used to interpret the shearing response of crushable and noncrushable soils. The results showed that calcareous sands have more tendencies in contraction. Particle shape and breakage play a key role in engineering behavior of crushable soils.     

234Th/238U activity ratios in Pacific Ocean bottom waters

The²³⁴Th/²³⁸U activity ratios in the near-bottom waters at a station in the South Pacific have been measured. The activity ratios are close to the secular equilibrium value, ranging between 0.9 and 1.13 (± 8%), suggesting that the rate of removal of²³⁴Th by bottom-water scavenging processes at this station is slow compared to its rate of radioactive decay. The mean²³⁴U/²³⁸U activity ratios in these waters is 1.14 ± 0.02, the same as the reported values for the world oceans.     

Study of surface runoff using physical models

. The profiles of overland water flow as a function of space and time obtained by applying kinematic wave approximations combined with the Darcy-Weisbach resistance formula to laminar flow are presented. Rainfall-excess is assumed to remain constant during a certain period of time. Runoff from surfaces of constant slope, with uniform surface texture, and the effects of different parameters on overland flow have been studied. Comparisons of runoff using Darcy-Weisbach, Manning, and Chezy resistance formulas have been made. It was found that the lower the rainfall-excess rates, the longer the surface runoff starting time, peak time, and smaller the peak runoff value at any distance. It was also found that the overland flow increases rapidly to the peak value, followed by a rapid decline which begins at the moment the rainfall-excess ceases, and then approaches zero slowly. Comparison of the theoretical calculations of runoff with the measured data of the Los Angeles field tests on concrete-paved surface shows good agreement.