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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

Acidification and nitrogen oxide : a survey of Asian soils and the effects of nitric oxide on fungi in an experimental model

Khan, Gulzar Ahmed January 1997 (has links)
No description available.
32

Nitrous oxide soil emissions from an organic and conventionally managed cropping system in Manitoba

Westphal, Megan 19 January 2017 (has links)
In recent decades the knowledge of nitrous oxide (N2O) emissions after the application of nitrogen (N) fertilizers in agriculture soil has improved. However the understanding of emissions of N2O from Canadian organic agricultural systems has not been developed. The Glenlea Long Term Crop Rotation is the longest running organic conventional comparison study in western Canada and was used here to compare N2O emissions between the systems. In organic cropping systems forage legumes such as alfalfa are incorporated into the soil as an N source. The amount of N2O that is emitted after the incorporation and during the subsequent crop is not well known. The wheat and legume phases (alfalfa (Medicago sativa) in organic system and soybean (Glycine max L.) in the conventional) of the rotation were monitored for N2O. In 2014, 2015, and spring 2016 (data still being analysed) emissions of N2O were monitored using the vented static chambers method as well, soil conditions (temperature, moisture, inorganic N and extractable carbon) and yields were measured. Typical N2O emissions from spring applied urea were observed after application in the conventional system however no emission episode was seen after the fall alfalfa plough down or during spring thaw in the organic system. Greater NO3- accumulation was observed in the organic treatments however low emissions were observed. The organic system resulted in lower yields for both years, but still resulted in lower emissions per amount of grain produced (yield-scaled emissions) than the conventional system. This study adds to the knowledge that N2O emissions from organic systems do differ from conventional however yields need to be improve to fully exploit the benefits. / February 2017
33

Forest conversion to smallholder plantations : the impacts on soil greenhouse gas emissions and termite diversity in Jambi, Sumatra

Aini, Fitri Khusyu January 2016 (has links)
Ongoing conversion of forests in Sumatra to agricultural lands might affect the biodiversity of soil fauna, such as termites, and emissions of nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2). To assess the impact of such forest conversions, this study was conducted in Jambi, Sumatra in an undisturbed forest (FR), a disturbed forest (DF), a one year old rubber plantation (RB1), a twenty year old rubber plantation (RB20) and an oil palm plantation (OP). The plantations belonged to smallholders and were not usually fertilized. The effect of fertilizer was assessed by applying N fertilizer and taking a series of intensive measurements. The N2O, CH4 and CO2 fluxes were measured using static chamber methods and termite species richness was assessed using a standard semi quantitative transect method. Forest conversion to smallholder plantations did not significantly affect the N2O, CH4 and CO2 fluxes, but the diversity and relative abundance of termites was decreased. this implies that the ecosystem services regulated by termites might decline. The application of N fertilizer at the conventional rate (141 kg N ha-1 y-1), with an emission factor of 3.1 % in the oil palm plantation, increased N2O emissions to twice as high as that in the undisturbed forest. The annual N2O and CH4 fluxes from termites amounted to 0.14, 0.21, 0.88, 2.47 and -0.56 kg ha-1 y-1 N2O-N and 0.85, 1.65, 3.80, 0.97 and 2.30 kg ha-1 y-1 CH4-C in the FR, DF, RB1, RB20 and OP, respectively. Further research is needed to understand the interannual variability of the N2O, CH4 and CO2 fluxes from soils and termites. Understanding the key drivers and underlying processes which regulate them would help to control the biodiversity loss and the change of N2O, CH4 and CO2 fluxes from soils and termites.
34

Economic impact assessment of carbon pricing of embodied greenhouse gas emissions for commercial office construction

Noller, Caroline J, Built Environment, Faculty of Built Environment, UNSW January 2005 (has links)
A life cycle study was undertaken to assess the economic impact arising from internalised embodied greenhouse gas emissions (GGE) costs for a commercial office building. A limited range of design and materials re-cycling strategies were investigated for their abatement potential. GGE quantities were determined by a hybrid process analysis where input-output data was supplemented with national average data to increase completeness whereby all upstream emissions arising from material inputs to the point of extraction, as well as non-material inputs (e.g. goods and services) into the design and construction process are accounted for. The hypothesis proposed abatement potential of 30%, as measured against the Benchmark Design (BM) would be economically viable in absence of the benefit of early-action credits. The hypothesis was disproved with 15% abatement shown at zero additional capital cost. A Stretch Technology (ST) scenario was investigated which showed 32% abatement potential however the associated marginal capital cost could not be determined. The GGE intensity per meter square of Net Lettable Area (m2 NLA) for the case study building was found to be 5,258 kg CO2-e. The theoretical value of abatement credits was determined at $12 to $1,031 / m2 NLA (depending on price) and is shown to present a reasonable economic and market transformation opportunity at medium range values. The results demonstrate that the cost-push inflation risk posed to commercial office construction is large where the price of embodied GGE is internalised in the economic system. Gross Construction Cost (GCC) increase per square meter is shown to be between 1.5% and 61% (with associated negative IRR impacts between -0.1 to -7%) depending on the GGE price level. An unsustainable cost impact is demonstrated at GGE prices greater than AUD$50 per tonne of carbon dioxide equivalent (AUD$50/ tonne CO2-e). Internalised GGE studies have been largely limited to the operational cost impact arising from GGE of direct end-use rather than from the perspective of total embodied final demand. The results demonstrate the critical nature of embodied abatement strategies for commercial buildings if the internationally accepted 60% global GGE abatement is to be achieved within the relevant timeframe. An average kg CO2-e intensity per dollar of GCC is proposed for the three building models that may be applied to general scenario planning. The scale of economic benefit available for embodied credits is significant and the determination of viable credit mechanisms worthy of further research.
35

Environmental Management Accounting for an Australian Cogeneration Company

Niap, Damian Tien Foo, e58018@ems.rmit.edu.au January 2007 (has links)
This research explores whether Environmental Management Accounting can be applied to assist an Australian cogeneration company in improving both its financial performance as well as its environmental performance. Cogeneration or 'combined heat and power', in this particular case, involves the simultaneous production of heat and electricity using a single fuel, that is, natural gas. The heat generated is then used to produce steam to meet the customers' requirements as well as boost the production of electricity. Therefore, cogeneration provides greater efficiencies compared to traditional electricity generation methods because it utilizes heat that would otherwise be wasted. In addition, greenhouse gases emissions can be reduced substantially. The approach taken in this research is to assess whether an improvement in the energy efficiency of the cogeneration plant can lead to a reduction in greenhouse gases emissions. An improvement in energy efficiency means that either: • less gas is consumed, thus leading to cost savings; or • more electricity is generated for the same quantity of gas consumed, which leads to an increase in income and consequently profit. Therefore, an improvement in energy efficiency means an improvement in the financial performance. In addition, a reduction in the quantity of gas consumed or generating as much electricity as possible from a given quantity of gas can lead to a reduction in greenhouse gases emissions which means an improvement in the company's environmental performance. A case study method, which involves an Australian cogeneration company, is adopted because this would provide valuable in-depth practical insight into the operations and mechanisms of a company that is involved in combined heat and power generation. A review of the literature and the evidence collected indicated that a cogeneration plant's efficiency can be improved at least back to near the plant's designed efficiency. And, further improvements may be achieved by utilizing the latest technology although this involves capital investment. It is also established that an improvement in plant efficiency can reduce greenhouse gases emissions. This research then concludes that Environmental Management Accounting can help the case study company improve its financial and environmental performances. An Environmental Management Accounting system can provide the physical information that is not available in the existing management accounting system. Physical information such as the physical quantities of gas consumed, electricity and steam produced, and greenhouse gases emitted, can help the company in decision-making relating to improving plant efficiency as well as reducing greenhouse gases emissions.
36

Evaluation of soil chemical and physical characteristics in a complex agroecosystem in the Argentine Pampa

Dyer, Lisa January 2010 (has links)
The Argentine Pampa is a global producer of maize (Zea mays L.) and soybean [Glycine max L. (Merr.), however agricultural practices have caused severe soil degradation and amplified greenhouse gas (GHG) production rates. This study presents the effects of maize-legume intercrops compared with maize and soybean sole crops on GHG production rates and soil physical properties over two field seasons. It also presents the results from a laboratory study in which GHGs were quantified from soils amended with maize and soybean crop residues. In the field study, soil organic carbon (SOC) concentrations were significantly greater (p<0.05) in the maize sole crop and intercrops, whereas soil bulk density was significantly lower in the intercrops and as a consequence soil infiltration was higher. Soil total nitrogen (TN) concentrations were not significantly different between treatments. Soil CO2 production rates were significantly greater in the maize sole crop but did not differ significantly for N2O. However, over the two field seasons both trace gases showed a general trend of greater production rates in the maize sole crop followed by the soybean sole crop. Linear regression between soil GHGs and soil temperature or volumetric soil moisture accounted for up to 51% of the variability in soil CO2 production rates and 60% of the soil N2O production rates. In the laboratory study, soil GHG production rates varied between treatments and between residue addition for both CO2 and N2O but varied only narrowly between treatments and experiments for CH4. Results from this study provided further insight into the effect of agroecosystem management practices on GHG production rates and soil physical and chemical characteristics, and contributed to improving our understanding of optimal agroecosystem design.
37

Combating climate change: the control of greenhouse gas emissions in Hong Kong

Choi, Chuen-yin., 蔡雋妍. January 2012 (has links)
published_or_final_version / Politics and Public Administration / Master / Master of Public Administration
38

The contribution of rural land uses to greenhouse gas neutral regions

Feliciano, Diana January 2012 (has links)
No description available.
39

Accelerating the demand for low emission vehicles : a consumer led perspective

Morton, Craig Lee January 2013 (has links)
Low Emission Vehicles (LEVs) represent a car classification which utilizes advancements in automotive technology to address policy objectives associated with energy security and greenhouse gas emissions. The effectiveness of LEVs at addressing these objectives will not only depend on their technical performance but also on their levels of adoption by consumers. With LEVs encompassing cars which are significantly different compared to conventional market options, the understanding of consumer response to these vehicles remains limited. This thesis addresses this limitation in existing knowledge by providing a detailed examination of consumer demand for LEVs in the UK. Through the application of psychometric methods, this thesis assesses the influence of socio-psychological constructs over LEV preference. A bespoke conceptual framework has been developed to provide insights regarding the influence of attitudes, emotions and values. This framework was applied to the design of a self completion household questionnaire distributed over the cities of Newcastle upon Tyne and Dundee. The meanings placed on car ownership are measured alongside the concept of innovativeness to determine if these traits are likely to hinder or advance LEV adoption. Additionally, past research has tended to consider consumer demand for LEVs at a market level perspective with little attention given to social stratification. This thesis advances knowledge in this area by producing a structural analysis of the emerging market for LEVs. Noteworthy consumer segments are identified, described and compared according to their socio-psychological profiles, socio-economic characteristics and LEV preferences. Principle results of the thesis are that socio-psychological constructs account for a greater degree of variance compared to socio-economic characteristics when explaining evaluations of LEVs. The propensity to consider cars through symbolic, emotive and functional meanings tends to decrease assessments made concerning the functional capabilities of LEVs. The concept of innovativeness displays a positive influence over preferences towards LEVs indicating that these vehicles are being considered as innovations. Moreover, heterogeneous consumer segments with unique socio-psychological and demographic profiles are emerging in the LEV market. These segments display a range of LEV preference structures from those which hold high preferences and are likely to characterize early adopters to those which exhibit low preferences and are likely to represent non-adopters.
40

Evaluation of soil chemical and physical characteristics in a complex agroecosystem in the Argentine Pampa

Dyer, Lisa January 2010 (has links)
The Argentine Pampa is a global producer of maize (Zea mays L.) and soybean [Glycine max L. (Merr.), however agricultural practices have caused severe soil degradation and amplified greenhouse gas (GHG) production rates. This study presents the effects of maize-legume intercrops compared with maize and soybean sole crops on GHG production rates and soil physical properties over two field seasons. It also presents the results from a laboratory study in which GHGs were quantified from soils amended with maize and soybean crop residues. In the field study, soil organic carbon (SOC) concentrations were significantly greater (p<0.05) in the maize sole crop and intercrops, whereas soil bulk density was significantly lower in the intercrops and as a consequence soil infiltration was higher. Soil total nitrogen (TN) concentrations were not significantly different between treatments. Soil CO2 production rates were significantly greater in the maize sole crop but did not differ significantly for N2O. However, over the two field seasons both trace gases showed a general trend of greater production rates in the maize sole crop followed by the soybean sole crop. Linear regression between soil GHGs and soil temperature or volumetric soil moisture accounted for up to 51% of the variability in soil CO2 production rates and 60% of the soil N2O production rates. In the laboratory study, soil GHG production rates varied between treatments and between residue addition for both CO2 and N2O but varied only narrowly between treatments and experiments for CH4. Results from this study provided further insight into the effect of agroecosystem management practices on GHG production rates and soil physical and chemical characteristics, and contributed to improving our understanding of optimal agroecosystem design.

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