Ethnic Enclave Reconfiguration: A ‘new’ Chinatown in the Making

Years of past research on traditional Chinatowns were based on the assumption that Chinatown is an ethnic enclave for a single ethnic minority, i.e. the Chinese. In recent years, one could observe significant changes over Chinatowns in terms of more Vietnamese presence. Yet, the transition process as an object of study is much under-represented in the literature on ethnic enclaves. Looking at ethnic business transition from Hong Kong to Vietnamese in Toronto’s Chinatown West, this paper argues strongly that ‘multiple ethnicity’ can coexist in an enclave. For this case study, the Chinatown is being reconfigured into a ‘new’ Chinatown. Drawing upon data from the authors’ Vietnamese Business Database that covers information between 1983 and 2003, we present both spatial and temporal analyses that offer insights into how the Vietnamese businesses grow through time. Our findings support the existence of a Vietnamization process in Toronto Chinatown West. However, its evolution is still in an infant stage. In some aspects, the incoming Vietnamese businesses display similarities with the remaining Hong Kong businesses. In sum, a total reconfiguration of Chinatown West in form and business nature is still unaccomplished. The conventional enclave concept which bases on the singularity of ethnic group has to be abandoned in view of rising occurrence of ethnic transition, particularly in this globalizing era.     

Hydrogeological and Gasgeochemical Earthquake Precursors – A Review for Application

Even if earthquake precursory signals can be identified, how can they be useful? This paper investigates relationships among the attributes of 229 proposed earthquake related gasgeochemical and hydrogeological precursory signals, and applies these results to improve future earthquake prediction strategies. Sub-groups of these reported signals and relationships between sub-groups are established using parameters, including earthquake magnitude, signal duration, precursory time, and epicentral distance to the monitoring site (original studies are used wherever possible to improve data quality). A strong correlation (r=0.86) between signal duration and precursory time was identified. This suggests a relationship between the investigated precursory signals and tectonic processes related to the referenced earthquakes. Moreover, these signals are categorized into four groups, reflecting differences in monitoring station densities, measurement methods and physical processes related to signal occurrence: (a) radon exhalation from the earth’s crust, (b) exhalation of other gases (helium, argon and others), (c) temporal variation in water level or discharge of springs and (d) temporal variation in temperature and dissolved ions in the water of the monitoring sites. In addition, boundary functions are used to separate signal group subsets. Finally, it is shown how these boundary functions can be used in the context of an earthquake prediction strategy by identifying potential minimum magnitudes and maximum epicentral distances from the monitoring site.     

The Potential of Fuzzy Multi-objective Model for Rainfall Forecasting from Typhoons

This study applies the fuzzy multi-objective approach to forecast short-term (around 24 h) typhoon rainfall, which can be implemented without much background meteorological knowledge. The physical characteristics of 40 typhoons, including route, central pressure, central velocity and cyclonic radius, were used as the data set. The fuzzy multi-objective method mined information from the database to forecast both the depth and pattern of rainfall, which were then combined to estimate a cumulative rainfall curve. The results of calibration with reference to 40 historical typhoon events and the results of validation using another five typhoon events indicate that the proposed model has the potential to forecast short-term cumulative rainfall curves if more variables can be included and more historical typhoon events can be collected to enlarge the database.     

Preliminary Quantitative Assessment of Earthquake Casualties and Damages

Prognostic estimations of the expected number of killed or injured people and about the approximate cost associated with the damages caused by earthquakes are made following a suitable methodology of wide-ranging application. For the preliminary assessment of human life losses due to the occurrence of a relatively strong earthquake we use a quantitative model consisting of a correlation between the number of casualties and the earthquake magnitude as a function of population density. The macroseismic intensity field is determined in accordance with an updated anelastic attenuation law, and the number of casualties within areas of different intensity is computed using an application developed in a geographic information system (GIS) environment, taking advantage of the possibilities of such a system for the treatment of space-distributed data. The casualty rate, defined as the number of killed people divided by the number of inhabitants of the affected region, is also computed and we show its variation for some urban concentrations with different population density. For a rough preliminary evaluation of the direct economic cost derived from the damages, equally through a GIS-based tool, we take into account the local social wealth as a function of the gross domestic product of the country. This last step is performed on the basis of the relationship of the macroseismic intensity to the earthquake economic loss in percentage of the wealth. Such an approach to the human casualty and damage levels is carried out for sites near important cities located in a seismically active zone of Spain, thus contributing to an easier taking of decisions in emergency preparedness planning, contemporary earthquake engineering and seismic risk prevention.     

Potential of Satellite Remote Sensing and GIS for Landslide Hazard Assessment in Southern Kyrgyzstan (Central Asia)

Big landslides are one of the main natural hazards in Kyrgyzstan, which are concentrated in the foothills of the high mountain ranges along the Eastern rim of the Fergana Basin. Because of the high number of landslides and their occurrence over large areas there is a strong need for effective and objective landslide hazard assessment at a regional scale. In Kyrgyzstan satellite remote sensing data represent the only source of multitemporal information about surface conditions covering large areas. Against this background the goal is the development of a satellite remote sensing and GIS-based system for quantitatively oriented and spatially differentiated hazard assessment. During the presented pilot investigations in the area of the Upper Maili Suu river basin a methodological framework has been developed incorporating remote sensing and GIS techniques for various levels of information extraction. So far, methodological investigations have been focused on the potential of satellite remote sensing data from different optical (Landsat-(E)TM, ASTER, MOMS-2P) and radar (ERS-1/2) systems for the creation of an improved knowledge basis for hazard assessment. This includes landslide identification, generation of topographic information and characterization of the geological setting. The derived primary information have been analyzed in a GIS environment to gain an improved process understanding as a main prerequisite for successful hazard assessment. The results show that currently available satellite remote sensing data are suitable for landslide investigation in Kyrgyzstan. Full exploitation of their information potential requires combined analysis with other thematic information based on methods of interactive and automated information extraction.     

Evaluation of superficial settlements in low overburden tunnel TBM excavation: Numerical approaches

In this paper the problem of the superficial settlements related to tunnel mechanised excavation is analysed considering a low overburden application example. The excavation of tunnels in urban areas has actually important diffusion. This kind of work always implies to guarantee the safety and the stability of the existing superficial structures. The use of a tunnel boring machine (TBM) represents a good method in these conditions and the estimation of the induced settlement represents a difficult engineering problem. The study shows the differences between three different numerical approaches; the results, function of the same loss of volume, evidence from a quantitative point of view, the ground settlement.     

Geotechnical characterisation of pyroclastic soils involved in huge flowslides

Landslides of the flow type involving granular geo-materials frequently result in casualties and damage to property because of the long travel distance and the high velocities that these may attain. This was true for the events that took place in Campania Region (Southern Italy) in May 1998, involving pyroclastic soils originating from explosive activities of the Somma-Vesuvius volcano. Although these phenomena have frequently affected various areas of the Campania region over the last few centuries, there were no useful geological and geotechnical references available in the aftermath of the May 1998 events. For this reason Salerno University, which was involved in the scientific management of the emergency, addressed the issue of acquiring data on the geological, geomorphological and hydrogeological features of the slopes where the landslides had taken place. The information acquired made it possible to set up a slope evolution model that is able to interpret, from a geological point of view, past and more recent landslides that had occurred in the same area. As preliminary geotechnical analyses had already validated the above model, more detailed investigations were performed both on the pore pressure regimen of the covers still in place as well as on the physical and mechanical properties of pyroclastic soils, in saturated and unsaturated conditions. The present paper begins by discussing the data acquired during the .rst phase of the studies and then goes on to illustrate the laboratory results so far obtained with the aid of approximate procedures. These help advance our knowledge of pyroclastic soils within a reasonable time frame, thus improving landslide triggering analysis.     

Experimental and numerical investigations of stresses in a fully grouted rock bolts

Rock bolts are widely used for rock reinforcement in hard-rock mining and civil engineering since a long time. However the use of fully grouted rock bolts and cable bolts is limited in coal mines. In order to improve performance of the rock bolts as a supplementary roof support system for any type of roof condition in coal measured formations, it is necessary to have a good understanding of the behavior of the bolt–grout and grout–rock interactions as well as the mechanism of load transfer in rock bolts.As the performance of grouted bolts depends on bond strength, extensive laboratory pullout as well as pushout tests were conducted in the present investigations with the variations in the bolt diameters, length and cement–water mixing ratios of grout. The load–displacement curves were developed and were verified with the numerical results obtained from finite element analysis using ALGOR software.Numerical models were validated for pushout tests and a detailed analysis was carried out to know the displacement, stress, strain distribution along the bolt.     

Seismic bearing capacity of shallow strip footings

Seismic bearing capacity of shallow strip footings in soil has been obtained in the form of pseudo-static seismic bearing capacity factors N_cd, N_qd and N_d, denoting the cohesion, surcharge and unit weight components, respectively, by an extensive numerical iteration technique. Limit equilibrium method of analysis with composite failure surface is assumed. The validity of the principle of superposition is examined. Effects of both the horizontal and vertical seismic acceleration coefficients have been found to always reduce the ultimate bearing capacity significantly. Results obtained by the present method of analysis are compared with the available results and are found to be the least in the seismic case.     

The 14-year Performance of a Compacted Clay Liner used as Part of a Composite Liner System for a Leachate Lagoon

The migration of contaminants through a 2.9 m thick compacted clay liner (CCL) for a landfill leachate lagoon is examined 14 years after construction. The clay liner formed the lower portion of the composite liner system but the geomembrane (GM) was found to have defects that had allowed leachate to migrate between the GM and CCL. Chloride, sodium, potassium, calcium and magnesium pore water profiles through the CCL are examined. It is shown that chloride migrated approximately 1.7 m into the CCL during the 14 years of the lagoon operation, sodium approximately 1.2 m, and potassium 0.7 m. Diffusion and sorption data from laboratory diffusion testing are utilized in combination with a finite layer contaminant transport model to predict field contaminant migration profiles through the composite liner system and to establish the time of ‘failure’ of the geomembrane at sometime between 0 and 6 years after installation. Relatively high sorptive uptake of potassium by the CCL soil is observed from batch testing and diffusion testing with field data suggesting an even larger amount of sorption. It is hypothesized that organic sludge matter at the base of the lagoon is responsible for potassium uptake from the leachate. This field case highlights the importance of the compacted clay liner as part of the composite liner system in acting as a diffusion barrier during the lifetime of the lagoon as well as using relatively non-conservative contaminants such as chloride and sodium to estimate geomembrane ‘failure’ times