Effect of soil conditions on uplift of underground structures in liquefied soil

In an earthquake, underground structures located in liquefiable soil deposits are susceptible to floatation following an earthquake event due to their lower unit weight relative to the surrounding saturated soil. Such uplift response of the buoyant structure is influenced by the soil it is buried in. In the case of a liquefiable soil deposit, the soil can lose its shear strength significantly in the event of an earthquake. If the soil liquefies fully, the buoyant structure can float towards the soil surface. However, a partly liquefied soil deposit retains some of its initial shear strength and resists the uplift. This paper discusses the different soil conditions and their influence on the uplift response of buoyant structures. © 2012 World Scientific Publishing Company.

The effect of inclined soil layers on surface vibration from underground railways using a semi-analytical approach

Ground vibration due to underground railways is a significant source of disturbance for people living or working near the subways. The numerical models used to predict vibration levels have inherent uncertainty which must be understood to give confidence in the predictions. A semi-analytical approach is developed herein to investigate the effect of soil layering on the surface vibration of a halfspace where both soil properties and layer inclination angles are varied. The study suggests that both material properties and inclination angle of the layers have significant effect ( ± 10dB) on the surface vibration response. © 2009 IOP Publishing Ltd.

Effect of microbial activities on the mobility of copper in stabilised contaminated soil

Stabilisation, using a wide range of binders including wastes, is most effective for heavy metal soil contamination. Bioremediation techniques, including bioaugmentation to enhance soil microbial population, are most effective for organic contaminants in the soil. For mixed contaminant scenarios a combination of these two techniques is currently being investigated. An essential issue in this combined remediation system is the effect of microbial processes on the leachability of the heavy metals. This paper considers the use of zeolite and compost as binder additives combined with bioaugmentation treatments and their effect on copper leachability in a model contaminated soil. Different leaching test conditions are considered including both NRA and TCLP batch leaching tests as well as flow-through column tests. Two flow rates are applied in the flow-through tests and the two leaching tests are compared. Recommendations are given as to the effectiveness of this combined remediation technique in the immobilisation of copper. © 2005 Taylor & Francis Group.

Fabrication of an organic field effect transistor using nano imprinting of Ag inks and semiconducting polymers

A simple and cheap procedure for flexible electronics fabrication was demonstrated by imprinting metallic nanoparticles (NPs) on flexible substrates. Silver NPs with an average diameter of 10 nm were prepared via an improved chemical approach and Ag Np ink was produced in α-terpineol with a concentration up to 15%. Silver micro/nanostructures with a dimension varying from nanometres to microns were produced on a flexible substrate (polyimide) by imprinting the as-prepared silver ink. The fine fluidic properties of an Ag NP/α-terpineol solution and low melting temperatures of silver nanoparticles render a low pressure and low temperature procedure, which is well suited for flexible electronics fabrication. The effects of sintering and mechanical bending on the conductivity of imprinted silver contacts were also investigated. Large area organic field effect transistors (OFET) on flexible substrates were fabricated using an imprinted silver electrode and semiconducting polymer. The OFET with silver electrodes imprinted from our prepared oleic acid stabilized Ag nanoparticle ink show an ideal ohmic contact; therefore, the OFET exhibit high performance (Ion/Ioff ratio: 1 × 103; mobility: 0.071 cm2 V-1 s-1). © 2010 IOP Publishing Ltd.