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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Essays in environmental and cultural economics

Jo, Ara January 2018 (has links)
This thesis approaches the global cooperation problem of climate change mitigation from a cultural standpoint. The research is inspired by the observation that voluntary efforts to reduce greenhouse gas emissions exist and more interestingly that there is heterogeneity in the level of voluntary action across countries. To what extent could this be explained by cultural differences? In Chapter 1, I argue the within-country culture of cooperation sustained by trust – the expectation that a random member of society is trustworthy – positively affects cooperative behavior in the international arena via reputation effects. I theoretically motivate this hypothesis and provide empirical evidence that countries associated with high trust have reduced greenhouse gas emissions more substantially than countries that display low levels of social trust. I further explore this line of argument in Chapter 2 by looking at how trust affects compliance. This chapter provides empirical evidence that trust facilitates firms’ compliance decisions in an international climate change regulation (EU ETS), which makes enforcement less costly in high-trust countries. In Chapter 3, I turn my attention to potential determinants of trust. The paper focuses on the effect of migration on trust among neighbors in the context of Mexico. The findings suggest that migration negatively affects the formation of trust between individuals due to the expected short-term nature of the relationship.
32

The impact of forest conversion to oil palm plantation on the internal nitrogen cycle of tropical lowland soils

Hamilton, Rachel Elizabeth January 2014 (has links)
This thesis seeks to quantify the effect of land use change from tropical forest to oil palm plantation on nitrogen biogeochemical cycling in Sabah, Malaysia (Borneo). Nitrogen cycling process rates and indices were examined across four forests and six oil palm plantations during the inter-monsoon and end of wet season in 2010 and 2012 respectively. Firstly, the study establishes a baseline to assess the impact of land use change along a chronosequence of forest succession. Results indicate that forests follow a trajectory of nitrogen recovery and increased “openness” to nitrogen cycling through secondary forest development. Secondly, the spatial and temporal variation of nitrogen cycling within oil palm plantations is assessed. Results show that plantation management practices result in spatial variability in soil nitrogen. Examining process rates revealed an increasing trend of N\(_2\)O emission and decreasing trends of soil organic matter content as plantations matured. However, season and soil type also affected denitrification and N\(_2\)O emission. Finally, a replicated comparison of process rates in forests and plantations on riparian and terra firme soils revealed that plantation establishment significantly altered rates of nitrogen cycling and resulted in greater emissions of N\(_2\)O from \(terra\) \(firme\) plantations.
33

Factors influencing human exposure assessment of organophosphorus flame retardants (OPFRS) via indoor dust ingestion

Ortiz Carrizales, Yessica Patricia January 2018 (has links)
Concentrations of selected organophosphate flame retardants (PFRs) were determined in samples of living room dust from differents countries with international differences in absolute concentrations and relative abundance of different PFRs. Other substantial international differences were observed that are likely attributable to variations in flame retardant legislation and use between different countries. Within-room, within-home, and between home temporal and spatial variation in concentrations of PFRs in floor dust and elevated surface dust was studied in 3 homes from Birmingham, UK. Of particular note are the seasonal variations in PFR concentrations where by higher concentrations were observed in spring and summer; and that between-home spatial variation was largely attributable to differences in flooring composition. Moreover, higher concentrations were generally found in elevated surface rather than floor dust. Concentrations of PFRs were determined in indoor air from houses and offices in Birmingham, UK. Finally, controlled chamber experiments were conducted to examine the magnitude and rate of PFR transfer from a treated fabric to dust via direct fabric-dust contact. A key finding was that source-to-dust transfer via direct contact occurs and over the time period of our experiments was proportional to the duration of contact; with the majority of PFRs, transfer from fabric to dust via direct contact occurs within the first 4 days of contact.
34

Aerosol pollution from gas flaring emissions in the Niger Delta region of West Africa

Fawole, Olusegun Gabriel January 2016 (has links)
Gas flaring, the disposal of gas through stacks in an open-air flame, is a common feature in the processing of crude oil, especially in oil-rich regions of the world. The rates of emission of pollutants from gas flaring depend on a number of factors including, but not limited to, fuel composition and quantity, stack geometry, flame/combustion characteristics, and prevailing meteorological conditions. In this work, new estimated emission factors (EFs) for carbon-containing pollutants (excluding PAH) are derived for a specified subset of flame condition. The air pollution dispersion model, ADMS5, is used to simulate the dispersion of pollutants from gas-flaring stacks in the Niger delta. Fuel composition and flare size play significant role in the dispersion pattern and ground-level concentrations of pollutants. To assess the significance of gas-flaring to atmospheric aerosol loading, AERONET aerosol signals are clustered using trajectory analysis to identify dominant aerosol sources at the Ilorin site (4.34o E, 8.32o N) in West Africa. From 7-day back-trajectory calculations over a 10-year period calculated using the UK Universities Global Atmospheric Modelling Programme (UGAMP) trajectory model, which is driven by analyses from the European Centre for Medium-Range Weather Forecasts (ECMWF), dominant sources are identified, using literature classifications: desert dust, biomass burning, and urban-industrial. Using a combination of synoptic trajectories and aerosol optical properties, a fourth source is distinguished: that due to gas flaring. An estimation of the relative impact of these different aerosol sources on the overall radiative forcing at the Ilorin AERONET site was the carried out.
35

Cooperation and coordination for landscape scale conservation : qualitative and experimental economics approach

Lozada Vazquez, Luz Maria January 2013 (has links)
Researchers have highlighted the need for landscape scale management for biodiversity and other services such as recreation and pollination. Ecological networks have been proposed as a tool to deliver multifunctional services. Despite public policy interest, implementation of this tool is difficult because, as other public goods, ecological networks require land managers to be paid; in addition the creation of the spatial configuration of the network requires land managers’ cooperation across holdings. This thesis presents a methodological framework to test an economic incentive called ‘1-2-1 coordination bonus’ to stimulate cooperation. It also analyses existing cases of cooperation and the potential of adaptive co-management (ACM) to develop ecological networks. The research carried out in the Dee catchment, North-East Scotland, suggests the existence of processes that echo ACM, however this ACM-potential is hampered by the lack of local ecological knowledge, power-sharing and evaluation cycles. Attitudes to conservation suggested the identification of three clusters of land managers based on land tenure: states, tenants and smallholding owners. Cooperation was more frequently found within each group than across groups. The methodological framework proved to be innovative and informative for the design of the ‘1-2-1 coordination bonus’ which could stimulate cooperation for ecological networks such as field margins for pollination. But if a robust network is needed then the bonus has to be accompanied by coordination through third parties and/or spatial targeting of the incentive to achieve a specific desired network-pattern.
36

Transient water table influence upon Light Non-Aqueous Phase Liquids (LNAPLs) redistribution : laboratory and modelling studies

Sun, Simiao January 2017 (has links)
Fluctuating water table conditions influence capillary-held LNAPL(Light Non-Aqueous Phase Liquids) mass above and below the water table. Risks posed by such dynamic source zones vary over time as water tables oscillate from tidal effects, seasonality or anthropogenic interferences. In this study, the first automated multiphase flow dynamic water table experimental system comprising both hardware and software, was developed to: i) automatically implement programmable cyclic water table fluctuations via Raspberry Pi\(^T\)\(^M\) based inexpensive electronics; ii) dynamically monitor the real-time saturation distributions of all fluids (red-dyed-LNAPL, blue-dyed-water and air) in 2-D sand tank, using high-temporal-and-spatial resolution automated multi-spectral photography; and iii) accurately interpret large detailed datasets via advanced multi-spectral imaging. Such automated data acquisition and processing permit LNAPL releases and their redistributions under oscillating water table to be demonstrated in videos of photographic records, interpreted 2-D saturation contours and 1-D profiles. Eight experimental scenarios were undertaken to discern the influencing mechanisms of cyclic fluctuations incorporating with other influential factors including aquifer media and heterogeneities, volume and timing of releases, etc. Applicability of standard modelling by NAPL simulator was exercised, which provided a good general match of overall features of the release and oscillation dynamics. The high-resolution-and-frequency detailed quantitative dataset harvested was expected to supplement and expand the theories of multiphase flow distribution in porous media, where owing to the realization of the automated system, unprecedented processes were captured; and serve as a robust validation source of numerical and conceptual models which are essential tools in contamination site characterization, prediction, and remediation.
37

Aerosol contributions to speleothem geochemistry

Dredge, Jonathan January 2014 (has links)
There is developing interest in cave aerosols due to the increasing awareness of their impacts on the cave environment and speleothems. This study presents the first multidisciplinary investigation into cave aerosols and their contribution to speleothem geochemistry. Modern monitoring of suspended aerosol concentrations, CO2 and temperature in Gough’s Cave, Cheddar Gorge have presented a strong relationship with cave ventilation processes. Temporal variations of aerosol levels have demonstrated the ability of aerosol monitoring to record seasonal ventilation shifts, beyond anthropogenic influences. When used in combination with more established monitoring methods, suspended aerosol monitoring is a beneficial addition to cave environmental studies Theoretical modelling and calculations based on modern aerosol monitoring have established that aerosol contributions are highly variable. Aerosol contributions are of greatest significance under slow growth or hiatus scenarios and high aerosol deposition scenarios. Marine and terrestrial aerosol contributions have been quantified in a flowstone core from New St Michaels Cave, Gibraltar. Additionally, bio-aerosol deposits and bacterial colonisation have been identified as a potential source of trace element bioaccumulation and flowstone coloration in Yarrangobilly Caves, Australia.
38

Imaging and analysis of natural and manufactured nanoparticles

Cieslak, Emilia January 2010 (has links)
Nanotechnology, a new science discipline, which studies design, characterization, production and applications of materials with sizes 1-100 nm, has marked a new breakthrough in technological development. It promises to revolutionise many aspects of modern life. However, with increasing markets and industrial scale of production, nanomaterials (NMs) became a potential, but largely unknown, risk to human health and the environment. Carbon based NMs including carbon nanotubes (CNTs) and fullerenes are an important class of NMs and are further studied in this thesis. Potential fate and behaviour of single-walled CNTs (SWCNTs) was investigated in natural waters using transmission electron microscopy (TEM) and atomic force microscopy (AFM). There was a focus on CNT interactions with natural aquatic colloids along with the impacts of other solution conditions at environmentally relevant levels. Similar research on fullerenes C60 was also undertaken, as a part of a wider study investigating fish ecotoxicology of fullerenes. Nanoscale atmospheric particles were imaged and analysed with AFM. Additionally, a pilot study on metal speciation in SWCNTaq was conducted to determine partitioning of Ni, Y, Cd, Cu and Cr between particle-bound, labile and dissolved fractions with a view to better understand the role of SWCNTs in trace metals binding (and thus influencing their transport, chemistry and bioavailability). The results indicate that SWCNTs in aquatic systems are likely to interact with natural nanoscale material. The experiments showed that SWCNTs in aqueous suspensions are stabilised with humic acid (probably by surface coating formation) and precipitated by divalent cations, while monovalent cations did not exhibit such destabilising effects. 95-100 % of yttrium (catalyst residue) was retained by the ultrafiltration membrane at all studied conditions indicating its particulate or particlebound speciation. On the other hand, the majority of chromium was dissolved. In general, the presence of humic acid decreased dissolved and labile metal species whereas Ca2+ had the opposite effect. Comparison of TEM and AFM results showed that both techniques are suitable to study suspended SWCNTs and produced consistent and complementary quantitative and qualitative results. An improved protocol (involving ultracentrifugation) for TEM specimen preparation was tested with aqueous suspensions of SWCNTs and nC60. It shortened the analysis time and improved reproducibility. The results show that fullerenes form very stable aqueous suspensions. However, the majority of the dispersed C60 occurs in microscale, rather than nanoscale aggregates, with only ca. 2% of material by mass between 1 and 100 nm. Visualisation of C60 in the presence of natural aquatic colloids did not show such strong interactions as in case of SWCNTs. Two analysed size fractions of atmospheric nanoparticles collected with an inertial impactor proved to be significantly contaminated with particles in the size range of 1-10 nm, which was attributed mainly to the diffusive mechanism of impaction for the imaged material.
39

Palaeobiology of Silurian trilobites from North Greenland

Hughes, Helen Elizabeth January 2010 (has links)
The Telychian (Llandovery, Silurian) reefs of North Greenland yield extensive collections of diverse and remarkably well preserved trilobites. The collections comprise 36 named trilobite species (32 new), and 30 under open nomenclature. These are assigned to 32 genera (six new). Members of the Scutelluidae (10 new species, four new genera), Illaenidae (one new species), Proetidae (10 new species, two new genera), Aulacopleuridae, Scharyiidae (three new species), Brachymetopidae, Harpetidae, Cheiruridae (three new species), Encrinuridae (two new species), Calymenidae, Phacopidae, Lichidae (two new species), and Odontopleuridae (one new species) are represented. Aspects of phylogenetic relationships within the Scutelluidae and Illaenidae are problematical because of the high number of effaced taxa. Selected effaced genera are analysed using cladistics, confirming the polyphyletic nature of effacement. Counts of trilobite sclerites from thirteen reef localities are analysed using cluster and correspondence analyses to identify trilobite associations, and taphonomic signatures. Seven trilobite associations are identified: Scutelluid-Illaenimorph; Scutelluid; Scutelluid-Cheirurid; Scutelluid-Harpetid; Proetid; Encrinurid; Illaenimorph. These can be encompassed within the previously defined Illaenid-Cheirurid ‘Community’. Trilobites are predominantly associated with a cement-rich microbial lithofacies deposited between storm- and fair-weather wave base. The variable distribution of taxa within the reefs is partly a reflection of intense hydrodynamic sorting in reef environments.
40

Water quality, biodiversity and ecosystem functioning in ponds across an urban land-use gradient in Birmingham, U.K

Thornhill, Ian January 2013 (has links)
The ecology of ponds is threatened by urbanisation and as cities expand pond habitats are disappearing at an alarming rate. Pond communities are structured by local (water quality, physical) and regional (land-use, connectivity) processes. Since ca1904 >80% of ponds in Birmingham, U.K., have been lost due to land-use intensification, resulting in an increasingly diffuse network. A survey of thirty urban ponds revealed high spatial and temporal variability in water quality, which frequently failed environmental standards. Most were eutrophic, although macrophyte-rich, well connected ponds supported macroinvertebrate assemblages of high conservation value. Statistically, local physical variables (e.g. shading) explained more variation, both in water quality and macroinvertebrate community composition than regional factors. Nonetheless, habitat availability within the wider landscape was important. Ecosystem functioning (leaf-litter breakdown) along a rural-urban gradient was confounded by habitat area, despite a decrease in functional redundancy. Ponds are identified that promote network connectivity and management of land-use within 100m may buffer against diffuse pollution with reductions in riparian shading required to improve growth conditions for oxygenating vegetation and to reduce nutrient levels. The results indicate that many urban ponds are threatened habitats that require active management to protect and restore water quality, biodiversity and ecosystem functioning.

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