Modified Method for prefabricated vertical drain consolidation analysis

Ground improvement with the prefabricated vertical drain (PVD) has become widely employed for soft ground treatment because of its economical and efficient method. While numerous numerical and analytical methods have been derived for PVD however, it is still an extensively high demand for a simpler and more accurate method for design steps. This paper proposes a method for solving the problem of one-dimensional (1D) consolidation with prefabricated vertical drains. The current approach introduces a 1D equivalent permeability, increasing linearly with depth to perform the consolidation of soft ground improved with PVD. The analytical solutions have been carried out and verified by analyses for two cases of one-way drainage and two-way drainage for uniform soil layer. The results show that the error of excess pore pressure determined by the proposed method is less than that obtained by the simpler method of Chai and smaller than 10% compared to the theoretical solution. The paper also compares the analytical solution with the FEM by ABAQUS software. It is found that the excess pore pressures and consolidation degrees obtained by these methods are similar and close to the theory. These confirm that the introduced 1D equivalent permeability can be employed to perform the consolidation of PVD improvement by analytical and FEM methods

Modified Method for prefabricated vertical drain consolidation analysis

Ground improvement with the prefabricated vertical drain (PVD) has become widely employed for soft ground treatment because of its economical and efficient method. While numerous numerical and analytical methods have been derived for PVD however, it is still an extensively high demand for a simpler and more accurate method for design steps. This paper proposes a method for solving the problem of one-dimensional (1D) consolidation with prefabricated vertical drains. The current approach introduces a 1D equivalent permeability, increasing linearly with depth to perform the consolidation of soft ground improved with PVD. The analytical solutions have been carried out and verified by analyses for two cases of one-way drainage and two-way drainage for uniform soil layer. The results show that the error of excess pore pressure determined by the proposed method is less than that obtained by the simpler method of Chai and smaller than 10% compared to the theoretical solution. The paper also compares the analytical solution with the FEM by ABAQUS software. It is found that the excess pore pressures and consolidation degrees obtained by these methods are similar and close to the theory. These confirm that the introduced 1D equivalent permeability can be employed to perform the consolidation of PVD improvement by analytical and FEM methods

Multimessenger astronomy with the Einstein Telescope

Gravitational waves (GWs) are expected to play a crucial role in the development of multimessenger astrophysics. The combination of GW observations with other astrophysical triggers, such as from gamma-ray and X-ray satellites, optical/radio telescopes, and neutrino detectors allows us to decipher science that would otherwise be inaccessible. In this paper, we provide a broad review from the multimessenger perspective of the science reach offered by the third generation interferometric GW detectors and by the Einstein Telescope (ET) in particular. We focus on cosmic transients, and base our estimates on the results obtained by ET's predecessors GEO, LIGO, and Virgo.Comment: 26 pages. 3 figures. Special issue of GRG on the Einstein Telescope. Minor corrections include

Strategies for Controlled Placement of Nanoscale Building Blocks

The capability of placing individual nanoscale building blocks on exact substrate locations in a controlled manner is one of the key requirements to realize future electronic, optical, and magnetic devices and sensors that are composed of such blocks. This article reviews some important advances in the strategies for controlled placement of nanoscale building blocks. In particular, we will overview template assisted placement that utilizes physical, molecular, or electrostatic templates, DNA-programmed assembly, placement using dielectrophoresis, approaches for non-close-packed assembly of spherical particles, and recent development of focused placement schemes including electrostatic funneling, focused placement via molecular gradient patterns, electrodynamic focusing of charged aerosols, and others

Cation exchange membranes based on graftes PS/DVB-EFTE films: an investigation of their electrochemical characteristics in sulfuric acid

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Properties of CMV cation exchange membranes in sulfuric acid media

Properties of CMV cation exchange membranes used for electrodialysis of sulfuric acid solutions were investigated. Membrane characterization has led to determine the ion-exchange capacity and the hydrogen ion transport number in sulphuric acid media. The membrane electrical conductivities were measured as a function of the acid concentration. These data were used to check the applicability of the micro-heterogeneous model which describes the inner membrane microstructure as consisting of a joint gel phase and an interstitial phase. The derived value of the interstitial phase volume fraction is large (20%). This value has been correlated to the membrane water content in terms of a model taking into consideration the molecular conformation of polyvalent (polystyrene sulfonate) macro-ions located in the joint gel phase. The behaviour of membranes placed respectively in their acid and salt forms have been studied and discussed. In the interpretation of membrane swelling and acid absorption, emphasis has been put on the role of polyelectrolyte morphological modifications as a function of the concentration in the equilibrating solutions. The overall membrane homogeneity has been tested by using chronopotentiometric measurements at different current densities. © 2006 Elsevier B.V. All rights reserved.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Cation exchange membranes based on grafted PS/DVB-ETFE films: An investigation of their electrochemical characteristics in sulfuric acid

The electrochemical characteristics of lab-made cation exchange membranes based on a PS/DVB-ETFE film with different degrees of grafting (37% and 44%, respectively) have been evaluated in presence of sulfuric acid by means of current-voltage, chronopotentiometric and conductivity measurements. The transport number of the hydrogen ion in the membranes is estimated by resorting to the Sand equation. The chronopotentiometric curves of the membranes in contact with 0.1 M H2SO4 solution present the typical shape of overall homogeneous membranes. The validity of the two-phase model (interstitial solution and gel phase) has therefore been tested with the aim of contributing to provide a better description of the membrane microheterogeneity. According to the two-phase model, the volume fraction of the interstitial phase in the membranes is determined from the membrane and solution conductivity data. Furthermore, the relationship between the interstitial phase volume fractions and the water content of the membranes is discussed on the basis of the polyelectrolyte theory. © 2009 Elsevier Ltd. All rights reserved.SCOPUS: ar.jinfo:eu-repo/semantics/publishe