This article examines spatial relationships between environmental hazards (i.e., pork feed lots, ... more This article examines spatial relationships between environmental hazards (i.e., pork feed lots, brick kilns, final assembly plants and a rail line) and markers of social marginality in Ciudad Juárez, Mexico. Juárez represents an opportunity for researchers to test for patterns of injustice in a recently urbanizing metropolis of the Global South. We use spatial-econometric modeling to predict the four unique hazard variables and a composite hazard variable using socio-demographic variables at the neighborhood level. Lower class and higher percentages of children and migrants were statistically significant predictors of composite hazard density. These results align with previous studies in the North. However, disaggregating these results by hazard type reveals important and counterintuitive differences in groups at risk based on the market-orientation of the hazard (i.e., domestic vs. transnational) and its location within the urban structure.
This dissertation investigates the crustal structure in the southwestern United States using diff... more This dissertation investigates the crustal structure in the southwestern United States using different geophysical techniques. Surface wave analysis of paths in the SBR, CP, RGR, SRM and GP were conducted. The Moho of TUC-EPT path in the SBR is estimated at 30 km with upper mantle velocity of 7.85 km/sec. The Moho for the TUC-ALQ path is estimated between 29-34 km with upper mantle velocity of 4.2 km/sec. This path passes through SBR, CP and RGR. The Moho for the GOL-ALQ path in the SRM and RGR is estimated between 40-45 km with upper mantle velocity of 7.9 km/sec. The Moho for ALQ-EPT path in the RGR is estimated between 32-37 km/sec showing thinning in crust toward the south. Crustal structure between EPT-JCT shows a gradual increase in velocity over the crust with the Moho estimated at 39-44 km depth, reflecting mostly the stable craton of the GP. The path between ALQ-LUB shows higher velocities in the lower crust of 4.0 km/sec with the Moho estimated at 37-42 km depth which is similar to EPT-JCT, showing the more stable craton of the GP. Shear wave velocities for the GOL-DAL-LUB path derived from the inversion are 3.2 km/sec for the upper crust (17 km thick), 3.9 km/sec for the lower crust (25 km thick), and 4.1 km/sec for the uppermost mantle. Crustal structure for the path LUB-GOL-RCD path derived from the inversion shows a gradual increase of velocity with the Moho estimated at a depth of 42-47 km. Receiver function analysis was conducted for the Lajitas seismic station for all three back azimuths, NW, SE and SW. Moho depth is estimated at 34-36 km with shear wave velocities of 4.2 km/sec in the uppermost mantle for all back azimuths. These results suggest that the RGR extends south, but its effect is minimized compared to the El Paso area. Receiver function results from the ANMO seismic station for all three back azimuths SW, SE and NW show the Moho at a depth of 36 km. Analysis of three seismic lines in southern New Mexico show a Moho depth of 30-32 km with velocity of 7.6--7.7 km/sec Gravity database for the US was complied and bad, duplicate, redundant, erroneous points were removed from the dataset. The database was stored in a relational database and its accessible from http://gis.utep.edu or http://research.utep.edu/paces or http://www.geongrid.org
Transportation Research Board 89th Annual MeetingTransportation Research Board, 2010
The infrastructure asset management (IAM) paradigm has emerged to assist in the challenging task ... more The infrastructure asset management (IAM) paradigm has emerged to assist in the challenging task of maintaining and improving infrastructure systems. However, IAM is data-driven and thus cannot be effective until proper tools and methods are developed for managing and integrating infrastructure data. Infrastructure data changes as new improvements to the infrastructure system are constructed and as new analysis results are incorporated. This paper presents the development and application of a tool (Update Layers) for updating infrastructure data in Geographical Information Systems (GIS). In such data environment, intersecting and creating new GIS layers in which calculations take place is required. Update Layers was created using a combination of ArcGIS’s Model Builder and VBA programming tools. The steps and processes taken to develop this data management tool are described in this paper, along with examples and an application of the tool to update the drainage infrastructure system of a case study area in the City of El Paso, TX.
Intelligent compaction (IC) is an emerging technology for quality management of compacted pavemen... more Intelligent compaction (IC) is an emerging technology for quality management of compacted pavement layers. Data collected by a vibration sensor and translated to a stiffness-based parameter is usually called the IC measurement value (ICMV). The ICMVs are coordinated with the global positioning system (GPS) data to assess the geospatial distribution of compacted layer properties. The IC rollers can be equipped with the original equipment manufacturer (OEM) systems that are provided by the vendors. However, with the recent introduction of the after-market or retrofit IC kits, it is possible to collect IC data with most regular vibratory rollers. Even though the use of the IC retrofit kits has been gaining popularity, its performance during the field operation has not been documented extensively. In this study, two dynamic vibratory rollers equipped with the OEM IC systems were employed along a test section. A retrofit kit was also installed on one of the rollers to collect the IC data during the same field operation simultaneously with the OEM system. The geospatial distribution of the ICMVs between the two types of systems for the most part was comparable. However, the magnitudes of the ICMVs among rollers and IC systems were somewhat different. These differences in the ICMVs were attributed to the differences in the vibration sensors and their installation as well as the data reduction algorithms among different systems. The reliability of the results from the OEM systems and retrofit kits seemed to be dependent on the proper installation of the vibration sensors as well as the accurate calibration of the GPS unit prior to the field data collection. A validation system and a standard protocol are needed to harmonize the performance of the IC rollers.
This study presents the evaluation of the compaction process on a lime-stabilized clayey subgrade... more This study presents the evaluation of the compaction process on a lime-stabilized clayey subgrade soil using the intelligent compaction (IC) technology. Two test beds with similar clayey subgrade soil were constructed with and without in-situ lime stabilization. These test beds were evaluated using several in situ nondestructive testing devices and an IC-equipped vibratory roller. The results from the study showed significant spatial variability in the in-situ test results and the roller measurements. In comparison to the untreated subgrade, the lime-stabilized test sections demonstrated a reduction in the variability of the roller measurements. The roller measurements on the stabilized section were influenced by the testing time and the underlying support conditions. The laboratory results and the field measurements using the roller and in-situ devices pointed to the improvement in the soil properties after stabilization. The moduli of the stabilized subgrade soil increased by almost two times. Statistical analyses demonstrated the influence of the underlying support condition, the moisture content and the lift thickness variations on the roller measurements.
Transportation Research Record: Journal of the Transportation Research Board, 2009
Optimal deployment of limited emergency response service (ERS) units in a metropolitan area is of... more Optimal deployment of limited emergency response service (ERS) units in a metropolitan area is of interest to public agencies. The limited emergency units not only have to respond to the demand for service by citizens and businesses but also have to cover critical infrastructures (CIs). The paper formulates an optimization model to allocate different types of ERS units among their candidate base stations. The allocation of units must ensure maximum coverage to CIs, subject to the capacities of the base stations, service standard in terms of time to reach the CIs, and the availability of the ERS units (when there are other competing demands for services). Unlike past models, the modeling approach here accounts for the fluctuation of travel time and demand frequency at different time periods of a typical day. The applicability of the model has been demonstrated in a case study in the city of El Paso, Texas, which allocates 45 firefighting units and 23 ambulances among 34 active fire s...
... 2008. "Missing Links: Foreign Investment and Industrial Development in Costa Rica and Me... more ... 2008. "Missing Links: Foreign Investment and Industrial Development in Costa Rica and Mexico." Studies in Comparative International Development 43(1):53-80. Pearce, Jamie, Simon Kingham and Peyman Zawar-Reza. 2006. ... Williams, Glyn, and Emma Mawdsley. 2006. ...
This article examines spatial relationships between environmental hazards (i.e., pork feed lots, ... more This article examines spatial relationships between environmental hazards (i.e., pork feed lots, brick kilns, final assembly plants and a rail line) and markers of social marginality in Ciudad Juárez, Mexico. Juárez represents an opportunity for researchers to test for patterns of injustice in a recently urbanizing metropolis of the Global South. We use spatial-econometric modeling to predict the four unique hazard variables and a composite hazard variable using socio-demographic variables at the neighborhood level. Lower class and higher percentages of children and migrants were statistically significant predictors of composite hazard density. These results align with previous studies in the North. However, disaggregating these results by hazard type reveals important and counterintuitive differences in groups at risk based on the market-orientation of the hazard (i.e., domestic vs. transnational) and its location within the urban structure.
This dissertation investigates the crustal structure in the southwestern United States using diff... more This dissertation investigates the crustal structure in the southwestern United States using different geophysical techniques. Surface wave analysis of paths in the SBR, CP, RGR, SRM and GP were conducted. The Moho of TUC-EPT path in the SBR is estimated at 30 km with upper mantle velocity of 7.85 km/sec. The Moho for the TUC-ALQ path is estimated between 29-34 km with upper mantle velocity of 4.2 km/sec. This path passes through SBR, CP and RGR. The Moho for the GOL-ALQ path in the SRM and RGR is estimated between 40-45 km with upper mantle velocity of 7.9 km/sec. The Moho for ALQ-EPT path in the RGR is estimated between 32-37 km/sec showing thinning in crust toward the south. Crustal structure between EPT-JCT shows a gradual increase in velocity over the crust with the Moho estimated at 39-44 km depth, reflecting mostly the stable craton of the GP. The path between ALQ-LUB shows higher velocities in the lower crust of 4.0 km/sec with the Moho estimated at 37-42 km depth which is similar to EPT-JCT, showing the more stable craton of the GP. Shear wave velocities for the GOL-DAL-LUB path derived from the inversion are 3.2 km/sec for the upper crust (17 km thick), 3.9 km/sec for the lower crust (25 km thick), and 4.1 km/sec for the uppermost mantle. Crustal structure for the path LUB-GOL-RCD path derived from the inversion shows a gradual increase of velocity with the Moho estimated at a depth of 42-47 km. Receiver function analysis was conducted for the Lajitas seismic station for all three back azimuths, NW, SE and SW. Moho depth is estimated at 34-36 km with shear wave velocities of 4.2 km/sec in the uppermost mantle for all back azimuths. These results suggest that the RGR extends south, but its effect is minimized compared to the El Paso area. Receiver function results from the ANMO seismic station for all three back azimuths SW, SE and NW show the Moho at a depth of 36 km. Analysis of three seismic lines in southern New Mexico show a Moho depth of 30-32 km with velocity of 7.6--7.7 km/sec Gravity database for the US was complied and bad, duplicate, redundant, erroneous points were removed from the dataset. The database was stored in a relational database and its accessible from http://gis.utep.edu or http://research.utep.edu/paces or http://www.geongrid.org
Transportation Research Board 89th Annual MeetingTransportation Research Board, 2010
The infrastructure asset management (IAM) paradigm has emerged to assist in the challenging task ... more The infrastructure asset management (IAM) paradigm has emerged to assist in the challenging task of maintaining and improving infrastructure systems. However, IAM is data-driven and thus cannot be effective until proper tools and methods are developed for managing and integrating infrastructure data. Infrastructure data changes as new improvements to the infrastructure system are constructed and as new analysis results are incorporated. This paper presents the development and application of a tool (Update Layers) for updating infrastructure data in Geographical Information Systems (GIS). In such data environment, intersecting and creating new GIS layers in which calculations take place is required. Update Layers was created using a combination of ArcGIS’s Model Builder and VBA programming tools. The steps and processes taken to develop this data management tool are described in this paper, along with examples and an application of the tool to update the drainage infrastructure system of a case study area in the City of El Paso, TX.
Intelligent compaction (IC) is an emerging technology for quality management of compacted pavemen... more Intelligent compaction (IC) is an emerging technology for quality management of compacted pavement layers. Data collected by a vibration sensor and translated to a stiffness-based parameter is usually called the IC measurement value (ICMV). The ICMVs are coordinated with the global positioning system (GPS) data to assess the geospatial distribution of compacted layer properties. The IC rollers can be equipped with the original equipment manufacturer (OEM) systems that are provided by the vendors. However, with the recent introduction of the after-market or retrofit IC kits, it is possible to collect IC data with most regular vibratory rollers. Even though the use of the IC retrofit kits has been gaining popularity, its performance during the field operation has not been documented extensively. In this study, two dynamic vibratory rollers equipped with the OEM IC systems were employed along a test section. A retrofit kit was also installed on one of the rollers to collect the IC data during the same field operation simultaneously with the OEM system. The geospatial distribution of the ICMVs between the two types of systems for the most part was comparable. However, the magnitudes of the ICMVs among rollers and IC systems were somewhat different. These differences in the ICMVs were attributed to the differences in the vibration sensors and their installation as well as the data reduction algorithms among different systems. The reliability of the results from the OEM systems and retrofit kits seemed to be dependent on the proper installation of the vibration sensors as well as the accurate calibration of the GPS unit prior to the field data collection. A validation system and a standard protocol are needed to harmonize the performance of the IC rollers.
This study presents the evaluation of the compaction process on a lime-stabilized clayey subgrade... more This study presents the evaluation of the compaction process on a lime-stabilized clayey subgrade soil using the intelligent compaction (IC) technology. Two test beds with similar clayey subgrade soil were constructed with and without in-situ lime stabilization. These test beds were evaluated using several in situ nondestructive testing devices and an IC-equipped vibratory roller. The results from the study showed significant spatial variability in the in-situ test results and the roller measurements. In comparison to the untreated subgrade, the lime-stabilized test sections demonstrated a reduction in the variability of the roller measurements. The roller measurements on the stabilized section were influenced by the testing time and the underlying support conditions. The laboratory results and the field measurements using the roller and in-situ devices pointed to the improvement in the soil properties after stabilization. The moduli of the stabilized subgrade soil increased by almost two times. Statistical analyses demonstrated the influence of the underlying support condition, the moisture content and the lift thickness variations on the roller measurements.
Transportation Research Record: Journal of the Transportation Research Board, 2009
Optimal deployment of limited emergency response service (ERS) units in a metropolitan area is of... more Optimal deployment of limited emergency response service (ERS) units in a metropolitan area is of interest to public agencies. The limited emergency units not only have to respond to the demand for service by citizens and businesses but also have to cover critical infrastructures (CIs). The paper formulates an optimization model to allocate different types of ERS units among their candidate base stations. The allocation of units must ensure maximum coverage to CIs, subject to the capacities of the base stations, service standard in terms of time to reach the CIs, and the availability of the ERS units (when there are other competing demands for services). Unlike past models, the modeling approach here accounts for the fluctuation of travel time and demand frequency at different time periods of a typical day. The applicability of the model has been demonstrated in a case study in the city of El Paso, Texas, which allocates 45 firefighting units and 23 ambulances among 34 active fire s...
... 2008. "Missing Links: Foreign Investment and Industrial Development in Costa Rica and Me... more ... 2008. "Missing Links: Foreign Investment and Industrial Development in Costa Rica and Mexico." Studies in Comparative International Development 43(1):53-80. Pearce, Jamie, Simon Kingham and Peyman Zawar-Reza. 2006. ... Williams, Glyn, and Emma Mawdsley. 2006. ...
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