Directional wave measurement at Haifa,Israel, and sediment transport along the Nile littoral cell

Results of three years of directional wave measurement at the Eastern Mediterranean coast of Haifa, Israel are presented. The wave-height and energy-flux distributions reveal a moderately high-energy coast with a bimodal annual cycle.The rate of wave-induced longshore sediment transport is estimated from the directional energy flux distributions. It describes an annual cycle with a maximum northward transport of 75 ± 14 × 10³ m³/month in midwinter and a southward transport of 26 ± 5 × 10³ m³/month in summer. The net annual transport is northward and computed at 110 ± 100 × 10³ m³/yr.We show that a wave-induced transport is sufficient in explaining the apparent transport of sediments in the Nile Littoral Cell, from the Nile Delta source to the Haifa Bay sink.     

Eta carinae nebulosities in 1963

The purpose of this note is to give further information regarding the positions of some condensations around Carinae in 1963, an epoch not yet considered in the literature. The new information is unable to confirm the deceleration hypothesis of theeir motion.     

Source mechanism of the 22/11/1995 Gulf of Aqaba earthquake and its aftershock sequence

The Gulf of Aqaba earthquake occurred on 22/11/1995 with M _W = 7.2 and was the largest event to occur along the Dead Sea Transform in at least a century. We determined the source mechanism of the event based on the inversion of the P and SH waveforms observed by teleseismic stations. Our solution consists of 2 similar subevents, where the first exhibits a left-lateral strike-slip motion with a normal component and the second subevent shows an almost pure left-lateral strike-slip motion along the gulf major fault system. The total seismic moment is 7.7 × 10²⁶ dyne-cm, with source duration of 15 seconds. The aftershock sequence was recorded by the regional broad band stations BGIO and JER, of the Israel Seismic Network, and KEG, of the MEDNET regional network for earthquakeswith M _W > 4.0. Aftershock epicenter seems to cluster mainly in the Eilat basin and the Aragonese basin. The dominant mechanism indicates left-lateral strike slip motion along the gulf trend, similar to the mainshock.     

Intermittent chaos in nonlinear wave–wave interactions in space plasmas

There is increasing observational evidence of nonlinear wave–wave interactions in space and astrophysical plasmas. We first review a number of theoretical models of nonlinear wave–wave interactions which our group has developed in the past years. We next describe a nonlinear three-mode truncated model of Alfvén waves, involving resonant interactions of one linearly unstable mode and two linearly damped modes. We construct a bifurcation diagram for this three-wave model and investigate the phenomenon of intermittent chaos. The theoretical results presented in this paper can improve our understanding of intermittent time series frequently observed in space and astrophysical plasmas.     

A smoothed cap model for variably saturated soils and its robust numerical implementation

This paper deals with the numerical implementation of a cap model for unsaturated soils. It provides a brief review of existing cap model approaches, based on which an improved model formulated in terms of generalised effective stress and matric suction is derived and described in detail. Although the proposed model is a multisurface plasticity model, it can efficiently be implemented using only single‐surface projections because of the smoothness of the model, which is obtained by construction. Numerical algorithms are provided for these single‐surface stress projections, using a single‐equation approach whenever possible. The robustness of the utilised single‐equation approaches is enhanced by proposing problem‐fitted start‐up procedures based on investigations of the nonlinear projection equations. A comparison of the model response with extensive material test data is used to validate the model and to demonstrate the robust application of the approach to silty sands and low to medium plasticity clays. Copyright © 2015 John Wiley & Sons, Ltd.     

Review and enhancement of 3D concrete models for large‐scale numerical simulations of concrete structures

The present paper focuses on selected plasticity and damage‐plasticity models for describing the 3D material behavior of concrete. In particular, a plasticity model and a damage‐plasticity model are reviewed and evaluated. Based on the results of the evaluation, enhancements are proposed, aiming at improving the correspondence between predicted and observed material behavior and aiming at implementing a robust and efficient stress update algorithm in a finite element program for performing large‐scale 3D numerical simulations of concrete structures. The capabilities of the concrete models are demonstrated by 3D numerical simulations of benchmark tests with combined bending and torsional loading and combined compression and shear loading and by a large‐scale 3D finite element analysis of a model test of a concrete arch dam. Copyright © 2011 John Wiley & Sons, Ltd.     

Effect of Drain Pipes on Uplift Force and Exit Hydraulic Gradient and the Design of Gravity Dams Using the Finite Element Method

Geotechnical and Geological Engineering - The effects of diameter and location of drain pipes on the uplift force and exit hydraulic gradient for a gravity dam are investigated. A numerical model...