The Experts below are selected from a list of 10266 Experts worldwide ranked by ideXlab platform
Erik Kjeang - One of the best experts on this subject based on the ideXlab platform.
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life cycle emissions and cost of transportation systems case study on diesel and natural gas for light duty trucks in municipal fleet operations
Journal of Natural Gas Science and Engineering, 2015Co-Authors: Mehdi Shahraeeni, Kourosh Malek, Syed Ahmed, Burke Van Drimmelen, Erik KjeangAbstract:Abstract The green economy mandate seeks to reduce transportation emissions by replacing traditional fossil fuels with alternative low-carbon fuels. The present article provides a comparative “cradle-to-grave” life cycle assessment (LCA) of light duty commercial vehicles (LDCVs) powered by compressed natural gas (CNG) and diesel. The LCA scope is based on conditions for municipal vehicle fleet operation in a semi-urban Canadian city, suitable for adoption of alternative fuels such as CNG. An in-house application is developed to conduct the LCA with a combination of real-time vehicle fleet data and Natural Resources Canada's GHGenius as the inventory database. The results indicate that the net energy consumed is comparable for both fuels. Mixed results are obtained for criteria Air Contaminant (CAC) emissions, indicating the need for exhaust treatment for both vehicles. More importantly, a 34% reduction of GHG emissions is predicted by replacing the diesel vehicles with CNG vehicles. The analysis of fugitive methane emissions caused by newly developed hydraulic fracturing methods shows that CNG vehicles are still favorable. The lifetime fuel cost can also be reduced by about $30,000 per vehicle by switching to CNG. Therefore, fleet operators and policy developers are recommended to consider adoption of CNG-powered LDCVs.
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Comparative life cycle assessment of hydrogen fuel cell passenger vehicles in different Canadian provinces
International Journal of Hydrogen Energy, 2015Co-Authors: Pouria Ahmadi, Erik KjeangAbstract:A comprehensive life cycle assessment of hydrogen fuel cell passenger vehicles (FCVs) is conducted based on relevant conditions for four major Canadian provinces. Results are provided for three alternative hydrogen production methods, namely electrolysis, thermochemical water splitting, and steam methane reforming of natural gas, and compared against conventional gasoline vehicles as a reference case. Significant reductions in greenhouse gas and criteria Air Contaminant emissions are predicted from all three hydrogen production methods in all four provinces, except for electrolysis in Alberta where most electricity is generated from fossil fuels. Thermochemical hydrogen production shows the most favorable results in all provinces due to the prospective use of renewable waste heat, followed by electrolysis from renewable hydroelectric power in Quebec and British Columbia. The sweet spot in terms of life cycle emission reductions is obtained when a renewable energy source for production is combined with a low-emission electricity source for compression and distribution, for example by utilizing waste heat and electricity from nuclear power in Ontario. The lowest fuel costs are predicted for hydrogen produced from natural gas, which is abundant in Canada and can provide a reasonable balance between emission reductions and economic benefits for FCV implementation across all provinces.
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a comparative life cycle assessment of diesel and compressed natural gas powered refuse collection vehicles in a canadian city
Energy Policy, 2013Co-Authors: Lars Rose, Mohammed Hussain, Syed Ahmed, Kourosh Malek, Robert Costanzo, Erik KjeangAbstract:Consumers and organizations worldwide are searching for low-carbon alternatives to conventional gasoline and diesel vehicles to reduce greenhouse gas (GHG) emissions and their impact on the environment. A comprehensive technique used to estimate overall cost and environmental impact of vehicles is known as life cycle assessment (LCA). In this article, a comparative LCA of diesel and compressed natural gas (CNG) powered heavy duty refuse collection vehicles (RCVs) is conducted. The analysis utilizes real-time operational data obtained from the City of Surrey in British Columbia, Canada. The impact of the two alternative vehicles is assessed from various points in their life. No net gain in energy use is found when a diesel powered RCV is replaced by a CNG powered RCV. However, significant reductions (approximately 24% CO2-equivalent) in GHG and criteria Air Contaminant (CAC) emissions are obtained. Moreover, fuel cost estimations based on 2011 price levels and a 5-year lifetime for both RCVs reveal that considerable cost savings may be achieved by switching to CNG vehicles. Thus, CNG RCVs are not only favorable in terms of reduced climate change impact but also cost effective compared to conventional diesel RCVs, and provide a viable and realistic near-term strategy for cities and municipalities to reduce GHG emissions.
Judit E G Smits - One of the best experts on this subject based on the ideXlab platform.
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enclosure design for flock level chronic exposure of birds to Air Contaminant mixtures
Toxicology Mechanisms and Methods, 2018Co-Authors: Michelle A North, David Kinniburgh, Judit E G SmitsAbstract:AbstractThe objective of this study was to design an enclosure suitable for studying the ecotoxicological effects of vehicle emissions on groups of wild birds without compromising welfare. Two, adjacent enclosures sheltered from sunlight, wind and rain, were bird-proofed and wrapped with thick polyethylene sheeting. Emissions were directed into the treatment enclosure from the exhaust of a light-duty gasoline truck, using flexible, heat-proof pipe, with joins sealed to prevent leakage. During active exposure, the engine was idled for 5 h/day, 6 days/week for 4 weeks. Fans maintained positive pressure (controls) and negative pressure (treatment), preventing cross-contamination of enclosures and protecting investigators. Four sets of passive, badge-type samplers were distributed across each enclosure, measuring nitrogen dioxide, sulfur dioxide and volatile organic compounds (NO2, SO2 and VOCs, respectively), and were complemented by active monitors measuring VOCs and particulate matter (2.5 µm diameter, PM2...
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detoxification endocrine and immune responses of tree swallow nestlings naturally exposed to Air Contaminants from the alberta oil sands
Science of The Total Environment, 2015Co-Authors: Luis Cruzmartinez, Kim J Fernie, Catherine Soos, Tom Harner, Fitsum Getachew, Judit E G SmitsAbstract:Changes in environmental and wildlife health from Contaminants in tailings water on the Canadian oil sands have been well-studied; however, effects of Air Contaminants on wildlife health have not. A field study was conducted to assess biological costs of natural exposure to oil sands-related Air emissions on birds. Nest boxes for tree swallows (Tachycineta bicolor) were erected at two sites; within 5 km of active oil sands mining and extraction, and ≥ 60 km south, at one reference site. Passive Air monitors were deployed at the nest boxes to measure nitrogen dioxide, sulfur dioxide, ozone, volatile organic compounds, and polycyclic aromatic hydrocarbons (PAHs). Nestlings were examined at day 9 post hatching to assess T cell function and morphometry. At day 14 post hatching, a subset of nestlings was euthanized to measure detoxification enzymes, endocrine changes, and histological alterations of immune organs. Except for ozone, all Air Contaminants were higher at the two oil sands sites than the reference site (up to 5-fold). Adult birds had similar reproductive performance among sites (p>0.05). Nestlings from industrial sites showed higher hepatic ethoxyresorufin O-dealkylase (EROD) induction (p 0.6), and no histological alterations in the spleen or bursa of Fabricius (p>0.05). This is the first report examining toxicological responses in wild birds exposed to Air Contaminants from industrial activity in the oil sands. It is also the first time that small, individual Air Contaminant monitors have been used to determine local Contaminant levels in ambient Air around nest boxes of wild birds.
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detoxification endocrine and immune responses of tree swallow nestlings naturally exposed to Air Contaminants from the alberta oil sands
Science of The Total Environment, 2015Co-Authors: Luis Cruzmartinez, Kim J Fernie, Catherine Soos, Tom Harner, Fitsum Getachew, Judit E G SmitsAbstract:Abstract Changes in environmental and wildlife health from Contaminants in tailings water on the Canadian oil sands have been well-studied; however, effects of Air Contaminants on wildlife health have not. A field study was conducted to assess biological costs of natural exposure to oil sands-related Air emissions on birds. Nest boxes for tree swallows ( Tachycineta bicolor ) were erected at two sites; within 5 km of active oil sands mining and extraction, and ≥ 60 km south, at one reference site. Passive Air monitors were deployed at the nest boxes to measure nitrogen dioxide, sulfur dioxide, ozone, volatile organic compounds, and polycyclic aromatic hydrocarbons (PAHs). Nestlings were examined at day 9 post hatching to assess T cell function and morphometry. At day 14 post hatching, a subset of nestlings was euthanized to measure detoxification enzymes, endocrine changes, and histological alterations of immune organs. Except for ozone, all Air Contaminants were higher at the two oil sands sites than the reference site (up to 5-fold). Adult birds had similar reproductive performance among sites ( p > 0.05). Nestlings from industrial sites showed higher hepatic ethoxyresorufin O -dealkylase (EROD) induction ( p p = 0.0001), a smaller T cell response to the phytohemagglutinin skin test ( p = 0.007), and smaller bursae of Fabricius ( p p = 0.01) at day 14 warrants cautious interpretation. There were no differences among nestlings for feather corticosterone ( p > 0.6), and no histological alterations in the spleen or bursa of Fabricius ( p > 0.05). This is the first report examining toxicological responses in wild birds exposed to Air Contaminants from industrial activity in the oil sands. It is also the first time that small, individual Air Contaminant monitors have been used to determine local Contaminant levels in ambient Air around nest boxes of wild birds.
Luis Cruzmartinez - One of the best experts on this subject based on the ideXlab platform.
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detoxification endocrine and immune responses of tree swallow nestlings naturally exposed to Air Contaminants from the alberta oil sands
Science of The Total Environment, 2015Co-Authors: Luis Cruzmartinez, Kim J Fernie, Catherine Soos, Tom Harner, Fitsum Getachew, Judit E G SmitsAbstract:Changes in environmental and wildlife health from Contaminants in tailings water on the Canadian oil sands have been well-studied; however, effects of Air Contaminants on wildlife health have not. A field study was conducted to assess biological costs of natural exposure to oil sands-related Air emissions on birds. Nest boxes for tree swallows (Tachycineta bicolor) were erected at two sites; within 5 km of active oil sands mining and extraction, and ≥ 60 km south, at one reference site. Passive Air monitors were deployed at the nest boxes to measure nitrogen dioxide, sulfur dioxide, ozone, volatile organic compounds, and polycyclic aromatic hydrocarbons (PAHs). Nestlings were examined at day 9 post hatching to assess T cell function and morphometry. At day 14 post hatching, a subset of nestlings was euthanized to measure detoxification enzymes, endocrine changes, and histological alterations of immune organs. Except for ozone, all Air Contaminants were higher at the two oil sands sites than the reference site (up to 5-fold). Adult birds had similar reproductive performance among sites (p>0.05). Nestlings from industrial sites showed higher hepatic ethoxyresorufin O-dealkylase (EROD) induction (p 0.6), and no histological alterations in the spleen or bursa of Fabricius (p>0.05). This is the first report examining toxicological responses in wild birds exposed to Air Contaminants from industrial activity in the oil sands. It is also the first time that small, individual Air Contaminant monitors have been used to determine local Contaminant levels in ambient Air around nest boxes of wild birds.
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detoxification endocrine and immune responses of tree swallow nestlings naturally exposed to Air Contaminants from the alberta oil sands
Science of The Total Environment, 2015Co-Authors: Luis Cruzmartinez, Kim J Fernie, Catherine Soos, Tom Harner, Fitsum Getachew, Judit E G SmitsAbstract:Abstract Changes in environmental and wildlife health from Contaminants in tailings water on the Canadian oil sands have been well-studied; however, effects of Air Contaminants on wildlife health have not. A field study was conducted to assess biological costs of natural exposure to oil sands-related Air emissions on birds. Nest boxes for tree swallows ( Tachycineta bicolor ) were erected at two sites; within 5 km of active oil sands mining and extraction, and ≥ 60 km south, at one reference site. Passive Air monitors were deployed at the nest boxes to measure nitrogen dioxide, sulfur dioxide, ozone, volatile organic compounds, and polycyclic aromatic hydrocarbons (PAHs). Nestlings were examined at day 9 post hatching to assess T cell function and morphometry. At day 14 post hatching, a subset of nestlings was euthanized to measure detoxification enzymes, endocrine changes, and histological alterations of immune organs. Except for ozone, all Air Contaminants were higher at the two oil sands sites than the reference site (up to 5-fold). Adult birds had similar reproductive performance among sites ( p > 0.05). Nestlings from industrial sites showed higher hepatic ethoxyresorufin O -dealkylase (EROD) induction ( p p = 0.0001), a smaller T cell response to the phytohemagglutinin skin test ( p = 0.007), and smaller bursae of Fabricius ( p p = 0.01) at day 14 warrants cautious interpretation. There were no differences among nestlings for feather corticosterone ( p > 0.6), and no histological alterations in the spleen or bursa of Fabricius ( p > 0.05). This is the first report examining toxicological responses in wild birds exposed to Air Contaminants from industrial activity in the oil sands. It is also the first time that small, individual Air Contaminant monitors have been used to determine local Contaminant levels in ambient Air around nest boxes of wild birds.
Lixian Liu - One of the best experts on this subject based on the ideXlab platform.
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step scan differential fourier transform infrared photoacoustic spectroscopy dftir pas a spectral deconvolution method for weak absorber detection in the presence of strongly overlapping background absorptions
Optics Letters, 2017Co-Authors: Lixian Liu, Andreas Mandelis, Huiting Huan, Kirk MichaelianAbstract:The determination of small absorption coefficients of trace gases in the atmosphere constitutes a challenge for analytical Air Contaminant measurements, especially in the presence of strongly absorbing backgrounds. A step-scan differential Fourier transform infrared photoacoustic spectroscopy (DFTIR-PAS) method was developed to suppress the coherent external noise and spurious photoacoustic (PA) signals caused by strongly absorbing backgrounds. The infrared absorption spectra of acetylene (C2H2) and local Air were used to verify the performance of the step-scan DFTIR-PAS method. A linear amplitude response to C2H2 concentrations from 100 to 5000 ppmv was observed, leading to a theoretical detection limit of 5 ppmv. The differential mode was capable of eliminating the coherent noise and dominant background gas signals, thereby revealing the presence of the otherwise hidden C2H2 weak absorption. Thus, the step-scan DFTIR-PAS modality was demonstrated to be an effective approach for monitoring weakly absorbing gases with absorption bands overlapped by strongly absorbing background species.
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step scan t cell fourier transform infrared photoacoustic spectroscopy ftir pas for detection of ambient Air Contaminants
Vibrational Spectroscopy, 2016Co-Authors: Lixian Liu, Andreas Mandelis, Huiting Huan, Kirk Michaelian, Alexander MelnikovAbstract:Abstract The theory of T-cells and their application in Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) based on a commercial FTIR spectrometer are discussed. This work was undertaken with the view to develop portable compact instrumentation for monitoring Air Contaminants. A resonant T-cell was determined to be the most appropriate resonator in view of the requirement for the low frequency and the limited space available in the FTIR spectrometer sample compartment. A two dimensional analytical solution with a semi-empirical boundary condition was introduced for resonance frequency prediction. Carbon dioxide (CO 2 ) gas was the chosen Air Contaminant. Linear amplitude response to CO 2 concentrations from 1000 to 8000 ppmv was observed, leading to a theoretical detection limit of 4 ppmv. The FTIR-PA phase shift was correlated to varying relaxation times in a mixture of CO 2 and nitrogen (N 2 ) gases. The analytical solution showed excellent agreement with simulated and experimental data, providing a reliable means for estimating the resonance frequency of the system. The experimental results establish the feasibility of using step-scan T-cell FTIR-PAS for quantitative detection of ambient Air pollutants.
Kirk Michaelian - One of the best experts on this subject based on the ideXlab platform.
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step scan differential fourier transform infrared photoacoustic spectroscopy dftir pas a spectral deconvolution method for weak absorber detection in the presence of strongly overlapping background absorptions
Optics Letters, 2017Co-Authors: Lixian Liu, Andreas Mandelis, Huiting Huan, Kirk MichaelianAbstract:The determination of small absorption coefficients of trace gases in the atmosphere constitutes a challenge for analytical Air Contaminant measurements, especially in the presence of strongly absorbing backgrounds. A step-scan differential Fourier transform infrared photoacoustic spectroscopy (DFTIR-PAS) method was developed to suppress the coherent external noise and spurious photoacoustic (PA) signals caused by strongly absorbing backgrounds. The infrared absorption spectra of acetylene (C2H2) and local Air were used to verify the performance of the step-scan DFTIR-PAS method. A linear amplitude response to C2H2 concentrations from 100 to 5000 ppmv was observed, leading to a theoretical detection limit of 5 ppmv. The differential mode was capable of eliminating the coherent noise and dominant background gas signals, thereby revealing the presence of the otherwise hidden C2H2 weak absorption. Thus, the step-scan DFTIR-PAS modality was demonstrated to be an effective approach for monitoring weakly absorbing gases with absorption bands overlapped by strongly absorbing background species.
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step scan t cell fourier transform infrared photoacoustic spectroscopy ftir pas for detection of ambient Air Contaminants
Vibrational Spectroscopy, 2016Co-Authors: Lixian Liu, Andreas Mandelis, Huiting Huan, Kirk Michaelian, Alexander MelnikovAbstract:Abstract The theory of T-cells and their application in Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) based on a commercial FTIR spectrometer are discussed. This work was undertaken with the view to develop portable compact instrumentation for monitoring Air Contaminants. A resonant T-cell was determined to be the most appropriate resonator in view of the requirement for the low frequency and the limited space available in the FTIR spectrometer sample compartment. A two dimensional analytical solution with a semi-empirical boundary condition was introduced for resonance frequency prediction. Carbon dioxide (CO 2 ) gas was the chosen Air Contaminant. Linear amplitude response to CO 2 concentrations from 1000 to 8000 ppmv was observed, leading to a theoretical detection limit of 4 ppmv. The FTIR-PA phase shift was correlated to varying relaxation times in a mixture of CO 2 and nitrogen (N 2 ) gases. The analytical solution showed excellent agreement with simulated and experimental data, providing a reliable means for estimating the resonance frequency of the system. The experimental results establish the feasibility of using step-scan T-cell FTIR-PAS for quantitative detection of ambient Air pollutants.