Research on seismic signals for vehicle targets and recognition by data fusion

This paper researches seismic signals of typical vehicle targets in order to extract features and to recognize vehicle targets. As a data fusion method, the technique of artificial neural networks combined with genetic algorithm(ANNCGA) is applied for recognition of seismic signals that belong to different kinds of vehicle targets. The technique of ANNCGA and its architecture have been presented. The algorithm had been used for classification and recognition of seismic signals of vehicle targets in the outdoor environment. Through experiments, it can be proven that seismic properties of target acquired are correct, ANNCGA data fusion method is effective to solve the problem of target recognition.

Lifecycle environmental impact and cost analyses of steel bridge piers with seismic risk

Lifecycle approaches have found their wide applications in analyzing, evaluating and assessing technologies and management methods in the infrastructure systems. While environmental problems such as global warming have become a serious issue in the world, researchers and practicing engineers in civil engineering have to pay attention to environmental impacts as well as function, safety, cost and aesthetics in the
whole lifecycle of civil infrastructures. In addition to the normal lifecycle activities accompanied with operation and aging, the effects of natural hazards such as earthquakes with a low occurrence probability but a high
hazard loss require a full consideration in determining both lifecycle cost and lifecycle environmental impact. In this research, an approach is proposed to predetermine the lifecycle environmental impact and costs of bridges from their construction and maintenance as well as the losses and recovery after natural hazards. Based on this research, it becomes possible to quantitatively outline the roles of bridge construction, maintenance and earthquake in both environmental impact and cost in the whole lifetime of a bridge, especially their constituent parts from seismic losses and recoveries.

Extending the surface force apparatus capabilities by using white light interferometry in reflection

The application of surface force apparatus (SFA) capabilities in measuring interactions between surfaces over nanometer separations was described. The technique is used when both the materials are transparent. It was observed that the poorly reflecting surface produce fringes that have low contrast and low finesse. The results show that the technique is successful when the visibility of the interference fringes is maximized.

Performance evaluation of open source seismic data processing packages

In many businesses, including hydrocarbon industries, reducing cost is of high priority. Although hydrocarbon industries appear able to afford the expensive computing infrastructure and software packages used to process seismic data in the search for hydrocarbon traps, it is always imperative to find ways to minimize cost. Seismic processing costs can be significantly reduced by using inexpensive, open source seismic data processing packages. However, hydrocarbon industries question the processing performance capability of open source packages, claiming that their seismic functions are less integrated and provide almost no technical guarantees for one to use. The objective of this paper is to demonstrate, through a comparative analysis, that open source seismic data processing packages are capable of executing the required seismic functions on an actual industrial workload. To achieve this objective we investigate whether or not open source seismic data processing packages can be executed using the same set of seismic data through data format conversions, and whether or not they can achieve reasonable performance and speedup when executing parallel seismic functions on a HPC cluster. Among the few open source packages available on the Internet, the subjects of our study are two popular packages: Seismic UNIX (SU) and Madagascar.

Comparisons of seismic rock slope stability assessments between the Hoek-Brown and Mohr-Coulomb failure criteria

Current investigations have shown that earthquakes can trigger significant damages of equipment, property infrastructure and environment. This is a persistent cause of economic loss for any country, especially for the loss of life. The conventional method for slope stability design is to utilize limit equilibrium method (LEM) in conjunction with the pseudo-static (PS) approach. However, the LEM has a significant drawback which is to determine the slip surface before factor of safety calculation. The numerical upper and lower bound limit analysis method employed in this paper can avoid this limitation. In this study, the presented slope stability evaluations considering earthquake effects based on the finite difference method will be discussed and compared with the results from the numerical limit analysis methods.

Investigation of seismic effects on disturbed rock slope stability assessments

For general stability analysis of rock slopes, rock mass strength and rock mass disturbance are definitely should be considered. In addition, the impact of earthquakes must be taken into account. In fact, the rock mass strength is very difficult to be assessed which causes the difficulty of analysing rock slope stability. Therefore, an empirical failure criterion, the Hoek-Brown failure criterion, has been proposed. It is one of the most widely accepted approaches to estimate rock mass strength. The rock mass disturbance is important and was found having significant influence on evaluating rock slope stability, especially for rock slope with poor quality rock mass. In the Hoek-Brown failure criterion, the disturbance factor can represent the level of the rock mass disturbance which would provide a reasonable basis for estimating rock mass strength. This research will not only discuss the slope factor of safety, but also consider the influence of the seismic force on rock slope stability assessment using pseudo-static method. In practice, only horizontal seismic coefficient is used. Various magnitudes of the disturbance factor and recommended blasting damage zone thickness are also taken into account. The blasting damage zone thickness considered ranges from 0.5 to 2.5 times of slope height. The research results have potential to be extended and then sets of comprehensive stability charts can be provided for the rock slope stability evaluations. They will be convenient tools for practising engineers. In this study, finite element upper bound and lower bound limit analysis methods are employed. Their applicability has been investigated in some previous studies. The differences between upper bound and lower bound solutions are less than ±10% which would provide reasonable and acceptable range for rock slope stability safety factor estimation.

Evaluation of numerical procedures to determine seismic response of structures under influence of soil-structure interaction

In this study, the accuracy and reliability of fully nonlinear method against equivalent linear method for dynamic analysis of soil-structure interaction is investigated comparing the predicted results of both numerical procedures with the results of experimental shaking table tests. An enhanced numerical soil-structure model has been developed which treats the behaviour of the soil and the structure with equal rigour. The soil-structural model comprises a 15 storey structural model resting on a soft soil inside a laminar soil container. The structural model was analysed under three different conditions: (i) fixed base model performing conventional time history dynamic analysis, (ii) flexible base model (considering full soil-structure interaction) conducting equivalent linear dynamic analysis, and (iii) flexible base model performing fully nonlinear dynamic analysis. The results of the above mentioned three cases in terms of lateral storey deflections and inter-storey drifts are determined and compared with the experimental results of shaking table tests. Comparing the experimental results with the numerical analysis predictions, it is noted that equivalent linear method of dynamic analysis underestimates the inelastic seismic response of mid-rise moment resisting building frames resting on soft soils in comparison to the fully nonlinear dynamic analysis method. Thus, inelastic design procedure, using equivalent linear method, cannot adequately guarantee the structural safety for mid-rise building frames resting on soft soils. However, results obtained from the fully nonlinear method of analysis fit the experimental results reasonably well. Therefore, this method is recommended to be used by practicing engineers.

Use of optical interferometry to measure gold nanoparticle adsorption on silica

Adsorption of metal nanoparticles is at the heart of many chemical and biosensor techniques, but there are few approaches that can provide quantitative characterisation of individual nanoparticle films fabricated at different times and/or under different conditions. Using synthesised gold nanoparticles (Au NPs) as a model, the nanoparticle films were investigated using an optical interferometry technique known as fringes of equal chromatic order (FECO), which was further systematically validated against both in situ quartz crystal microbalance (QCM) and ex situ atomic force microscopy (AFM) measurements. The results indicate that the FECO wavelengths has a quantifiable red shift with increasing particle densities, making it possible to quantify the degree of surface coverage via the analysis of the fringe shift at a fixed fringe order. Moreover, the calculated formula between the FECO shifts and the surface coverage allows quantitative analysis of the whole adsorption kinetics investigated. Particularly, the as-proposed FECO technique can successfully monitor the Au NP adsorption in situ, which could be a new versatile technology platform for “online” monitoring method, for example in biosensor applications using Au NP-tagged analytes.