1,720,983 research outputs found
Factors Affecting Hydrocarbon Vapor Transport From Leaking Storage Tanks to Buildings in Texas
No full textAs of January 1998, 152,000 underground storage tanks containing mainly common petroleum fuels such as gasoline, diesel fuel, kerosene, jet fuel, and aviation gasoline were located at 63,400 facilities in Texas. Since 1986, the Texas Natural Resource Conservation Commission (TNRCC) has documented more than 20,000 known leaking petroleum storage tank (LPST) sites in the state. The contamination caused by these releases may be limited to minor soil contamination or, in more serious cases, it may migrate to the groundwater and travel to drinking water wells. One of the most serious hazards of leaking storage tanks, vapor impacts to buildings, often requires emergency measures to prevent potential explosions. Fortunately, vapor impacts occur in only a small proportion of the sites with petroleum storage tanks. The occurrence of vapor impacts appears to be a result of a combination of factors involving the depth to groundwater, soil type, precipitation, type of petroleum product, and the presence of phase-separated hydrocarbons (also termed free product). The most common vapor impact occurs from a release of gasoline into clayey soil that results in phase-separated hydrocarbons (PSH) on shallow groundwater. Sites with a shallow, impermeable rock layer are particularly susceptible to vapor migration. Underground utility lines in contact with, or near, the groundwater allow for easy transport of the vapors into nearby buildings. Precipitation events that release adsorbed hydrocarbons by wetting the soils appear to initiate most vapor impacts. The results of this study will be used to identify those leaking storage tank sites which may result in a vapor impact so that monitoring and corrective measures can be initiated as necessary.Geography and Environmental Studie
Ecotourism Demand and Supply in El Cielo Biosphere Reserve, Tamaulipas, Mexico
No full textEcotourism development is a comparatively new research topic. Owners, planners, and designers typically rely more on intuition rather than research when planning for ecotourism development. Details of tourism demand and the supply of goods and services, as well as the linkages between the two, must be understood in order to successfully develop ecotourism as a profitable local industry. I used a visitor questionnaire distributed over the six busiest visitation months to determine visitor demand characteristics in El Cielo Biosphere Reserve in Tamaulipas, Mexico. The questionnaire was also used to measure the adequacy of supply and to identify site usage and spending patterns within the most heavily traveled tourist corridor in the reserve. I also incorporated observations of tourists and unstructured interviews with tourists and residents in the study, which identified that the supply of services, goods, and infrastructure is adequate to meet the demands of four primary tourist types identified. Likewise, I developed supply improvement recommendations to aid the residents of the study area in accommodating growing tourist demands in the reserve, which has little visitor management, no enforcement or compliance mechanisms, and no ongoing monitoring of natural resources.Geography and Environmental Studie
Water Quality Issues in the Cypress Creek Watershed
No full textNo abstract prepared.Geography and Environmental Studie
Environmental Equity and Community Participation in the Superfund Process
No full textNo abstract prepared.Geography and Environmental Studie
Attachment to place: Our Lady of Guadalupe Parish and the Guadalupe neighborhood
No full textNo abstract prepared.Geography and Environmental Studie
Environmental Factors Affecting Protection and Propagation of the Longnose Darter
No full textNo abstract prepared.Geography and Environmental Studie
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Exploring the Function of Learning in Nature Tourism: Toward an Operational Definition and Conceptual Framework
No full textNo abstract prepared.Geography and Environmental Studie
Through the Lens of Katrina: A Historical Geography of the Social Patterns of Flood Exposure in New Orleans, 1970-2005
No full textTwo and a half years after Hurricane Katrina, its reverberations remain evident in New Orleans and throughout the academic literature. Although scholars have written extensively on apparent social inequities present in the city before, during, and after the storm, an empirical consensus on the racial and socioeconomic distributions of the population relative to Katrina-induced flooding remains elusive. In response to this lacuna, I employ the U.S. Census, digital inundation data, and a GIS to analyze New Orleans' racial and socioeconomic geographies as they related to patterns of flood inundation in the city during the storm. Katrina’s inundation, however, represents only a brief episode within the greater history of New Orleans. While a temporally isolated analysis of a distinctive hazard event such as Katrina can be informative in and of itself, it does little to illuminate the evolution of the social landscape before or after the storm.
Therefore, after conducting the initial analysis, I then replicate the methodology across the three decennial census periods prior to 2000 (1970, 1980, and 1990). While the initial assessment discerns the statistical relationship among race, socioeconomics, and Katrina’s inundation, the subsequent temporal analysis illuminates the historical patterns of social change that led to the landscape of exposure wrought by the storm in 2005. In essence, this research asks, "If Hurricane Katrina struck in 1970, 1980, or 1990, how, if at all, would the socioeconomic or racial geographies of flood exposure evident during each period differ from the patterns evident during the actual event in 2005?" I use Katrina’s inundation, then, as a lens through which we can view 35 years of urban social changes in New Orleans. I contend that it is not enough to understand merely whom the storm affected. Rather, scholars, managers, and policymakers at every level benefit by recognizing the evolution (or devolution) of social landscapes into those ripe for human disaster.Geography and Environmental Studie
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