40 CFR Appendix D to Part 60 - Required Emission Inventory Information

Code of Federal Regulations, 2013 CFR

2013-07-01

... one device operates in series. The method of control efficiency determination shall be indicated (e.g., design efficiency, measured efficiency, estimated efficiency). (iii) Annual average control efficiency, in percent, taking into account control equipment down time. This shall be a combined efficiency when...

40 CFR Appendix D to Part 60 - Required Emission Inventory Information

Code of Federal Regulations, 2014 CFR

2014-07-01

... one device operates in series. The method of control efficiency determination shall be indicated (e.g., design efficiency, measured efficiency, estimated efficiency). (iii) Annual average control efficiency, in percent, taking into account control equipment down time. This shall be a combined efficiency when...

Model predictive control of a lean-burn gasoline engine coupled with a passive selective catalytic reduction system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Pingen; Lin, Qinghua; Prikhodko, Vitaly Y.

Lean-burn gasoline engines have demonstrated 10–20% engine efficiency gain over stoichiometric engines and are widely considered as a promising technology for meeting the 54.5 miles-per-gallon (mpg) Corporate Average Fuel Economy standard by 2025. Nevertheless, NOx emissions control for lean-burn gasoline for meeting the stringent EPA Tier 3 emission standards has been one of the main challenges towards the commercialization of highly-efficient lean-burn gasoline engines in the United States. Passive selective catalytic reduction (SCR) systems, which consist of a three-way catalyst and SCR, have demonstrated great potentials of effectively reducing NOx emissions for lean gasoline engines but may cause significant fuelmore » penalty due to ammonia generation via rich engine combustion. The purpose of this study is to develop a model-predictive control (MPC) scheme for a lean-burn gasoline engine coupled with a passive SCR system to minimize the fuel penalty associated with passive SCR operation while satisfying stringent NOx and NH3 emissions requirements. Simulation results demonstrate that the MPC-based control can reduce the fuel penalty by 47.7% in a simulated US06 cycle and 32.0% in a simulated UDDS cycle, compared to the baseline control, while achieving over 96% deNOx efficiency and less than 15 ppm tailpipe ammonia slip. The proposed MPC control can potentially enable high engine efficiency gain for highly-efficient lean-burn gasoline engine while meeting the stringent EPA Tier 3 emission standards.« less

40 CFR 63.3555 - How do I determine the outlet THC emissions and add-on control device emission destruction or...

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 13 2013-07-01 2012-07-01 true How do I determine the outlet THC... Control Efficiency/outlet Concentration Option § 63.3555 How do I determine the outlet THC emissions and... methods in this section to determine either the outlet THC emissions or add-on control device emission...

40 CFR 63.3555 - How do I determine the outlet THC emissions and add-on control device emission destruction or...

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 13 2014-07-01 2014-07-01 false How do I determine the outlet THC... Control Efficiency/outlet Concentration Option § 63.3555 How do I determine the outlet THC emissions and... methods in this section to determine either the outlet THC emissions or add-on control device emission...

40 CFR 63.3555 - How do I determine the outlet THC emissions and add-on control device emission destruction or...

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 13 2012-07-01 2012-07-01 false How do I determine the outlet THC... Control Efficiency/outlet Concentration Option § 63.3555 How do I determine the outlet THC emissions and... methods in this section to determine either the outlet THC emissions or add-on control device emission...

MUNICIPAL WASTE COMBUSTION MULTIPOLLUTANT STUDY EMISSION TEST REPORT, MAINE ENERGY RECOVERY COMPANY, REFUSE DERIVED FUEL FACILITY, BIDDEFORD, MAINE - VOLUME III: APPENDICES G-N

EPA Science Inventory

The report gives results of an emission test of a new municipal solid waste combustor, in Biddeford, ME, that burns refuse-derived fuel and is equipped with a lime spray dryer fabric filter (SD/FF) emission control system. Control efficiency of the SD/FF emission control system ...

MUNICIPAL WASTE COMBUSTION MULTIPOLLUTANT STUDY EMISSION TEST REPORT, MAINE ENERGY RECOVERY COMPANY, REFUSE DERIVED FUEL FACILITY, BIDDEFORD, MAINE - VOLUME II: APPENDICES A-F

EPA Science Inventory

The report gives results of an emission test of a new municipal solid waste combustor, in Biddeford, ME, that burns refuse-derived fuel and is equipped with a lime spray dryer fabric filter (SD/FF) emission control system. Control efficiency of the SD/FF emission control system ...

Policy design and performance of emissions trading markets: an adaptive agent-based analysis.

PubMed

Bing, Zhang; Qinqin, Yu; Jun, Bi

2010-08-01

Emissions trading is considered to be a cost-effective environmental economic instrument for pollution control. However, the pilot emissions trading programs in China have failed to bring remarkable success in the campaign for pollution control. The policy design of an emissions trading program is found to have a decisive impact on its performance. In this study, an artificial market for sulfur dioxide (SO2) emissions trading applying the agent-based model was constructed. The performance of the Jiangsu SO2 emissions trading market under different policy design scenario was also examined. Results show that the market efficiency of emissions trading is significantly affected by policy design and existing policies. China's coal-electricity price system is the principal factor influencing the performance of the SO2 emissions trading market. Transaction costs would also reduce market efficiency. In addition, current-level emissions discharge fee/tax and banking mechanisms do not distinctly affect policy performance. Thus, applying emissions trading in emission control in China should consider policy design and interaction with other existing policies.

The blue skies in Beijing during APEC 2014: A quantitative assessment of emission control efficiency and meteorological influence

NASA Astrophysics Data System (ADS)

Liu, Hongli; He, Jing; Guo, Jianping; Miao, Yucong; Yin, Jinfang; Wang, Yuan; Xu, Hui; Liu, Huan; Yan, Yan; Li, Yuan; Zhai, Panmao

2017-10-01

Most previous studies attributed the alleviation of aerosol pollution to either emission control measures or favorable meteorological conditions. However, our understanding of their quantitative contribution is far from complete. In this study, based on model simulation using the CMA (China Meteorological Administration) Unified Atmospheric Chemistry Environment for aerosols (CUACE/Aero), in combination with simultaneous ground-based hourly PM2.5 observations, we aim to quantify the relative contributions of the emission control measures and meteorology to the blue-skies seen in Beijing during the Asia-Pacific Economic Cooperation (APEC) summit held in November of 2014. A series of model simulations have been performed over Beijing-Tianjin-Hebei (BTH) region by implementing nine different emission control schemes. To investigate the relative contributions of the emission control measures and meteorology, the study period has been divided into five episodes. Overall, the CUACE/Aero model can reasonably well reproduce the temporal and spatial evolution of PM2.5 during APEC 2014, although the model performance varies by different time periods and regions of interest. Model results show the emission control measures on average reduced the PM2.5 concentration by 41.3% in urban areas of Beijing and 39.7% in Huairou district, respectively, indicating emission control plays a significant role for the blue skies observed. Among all the emission control measures under investigation, local emission control in Beijing contributed the largest to the reduction of PM2.5 concentrations with a reduction of 35.5% in urban area of Beijing and 34.8% in Huairou, in contrast with the vehicle emission control in Hebei that contributed the least with a reduction of less than 1%. The emission control efficiency in five episodes has been assessed quantitatively, which falls in the range of 36.2%-41.2% in urban area of Beijing and 34.9%-40.7% in Huairou, indicative of no significant episode and geographic dependence in the emission control efficiency. The emission control measures and meteorology, however, alternated to dominate the absolute reduction of PM2.5 concentrations. When the weather conditions are unfavorable, emission control measures outperformed meteorology with a reduction of 55.3-59.4 μg/m3 in urban area of Beijing and 32.5-33 μg/m3 in Huairou. Conversely, when the northwesterly winds prevailed, meteorology tends to outweigh the role of emission control in accounting for the drop of PM2.5. The atmospheric dilution conditions are determined through the model calculation of the mass inflow of PM2.5 per unit volume near the surface. Our findings have significant implications for effective planning and implementation of emission control measures.

40 CFR Appendix D to Part 61 - Methods for Estimating Radionuclide Emissions

Code of Federal Regulations, 2011 CFR

2011-07-01

... Table 1. Table 1—Adjustment to Emission Factors for Effluent Controls Controls Types of radionuclides... applicable to gaseous radionuclides; periodic testing is prudent to ensure high removal efficiency. Fabric...

40 CFR Appendix D to Part 61 - Methods for Estimating Radionuclide Emissions

Code of Federal Regulations, 2013 CFR

2013-07-01

... Table 1. Table 1—Adjustment to Emission Factors for Effluent Controls Controls Types of radionuclides... applicable to gaseous radionuclides; periodic testing is prudent to ensure high removal efficiency. Fabric...

Controlling thermal emission with refractory epsilon-near-zero metamaterials via topological transitions

NASA Astrophysics Data System (ADS)

Dyachenko, P. N.; Molesky, S.; Petrov, A. Yu; Störmer, M.; Krekeler, T.; Lang, S.; Ritter, M.; Jacob, Z.; Eich, M.

2016-06-01

Control of thermal radiation at high temperatures is vital for waste heat recovery and for high-efficiency thermophotovoltaic (TPV) conversion. Previously, structural resonances utilizing gratings, thin film resonances, metasurfaces and photonic crystals were used to spectrally control thermal emission, often requiring lithographic structuring of the surface and causing significant angle dependence. In contrast, here, we demonstrate a refractory W-HfO2 metamaterial, which controls thermal emission through an engineered dielectric response function. The epsilon-near-zero frequency of a metamaterial and the connected optical topological transition (OTT) are adjusted to selectively enhance and suppress the thermal emission in the near-infrared spectrum, crucial for improved TPV efficiency. The near-omnidirectional and spectrally selective emitter is obtained as the emission changes due to material properties and not due to resonances or interference effects, marking a paradigm shift in thermal engineering approaches. We experimentally demonstrate the OTT in a thermally stable metamaterial at high temperatures of 1,000 °C.

Controlling thermal emission with refractory epsilon-near-zero metamaterials via topological transitions

PubMed Central

Dyachenko, P. N.; Molesky, S.; Petrov, A. Yu; Störmer, M.; Krekeler, T.; Lang, S.; Ritter, M.; Jacob, Z.; Eich, M.

2016-01-01

Control of thermal radiation at high temperatures is vital for waste heat recovery and for high-efficiency thermophotovoltaic (TPV) conversion. Previously, structural resonances utilizing gratings, thin film resonances, metasurfaces and photonic crystals were used to spectrally control thermal emission, often requiring lithographic structuring of the surface and causing significant angle dependence. In contrast, here, we demonstrate a refractory W-HfO2 metamaterial, which controls thermal emission through an engineered dielectric response function. The epsilon-near-zero frequency of a metamaterial and the connected optical topological transition (OTT) are adjusted to selectively enhance and suppress the thermal emission in the near-infrared spectrum, crucial for improved TPV efficiency. The near-omnidirectional and spectrally selective emitter is obtained as the emission changes due to material properties and not due to resonances or interference effects, marking a paradigm shift in thermal engineering approaches. We experimentally demonstrate the OTT in a thermally stable metamaterial at high temperatures of 1,000 °C. PMID:27263653

MUNICIPAL WASTE COMBUSTION MULTIPOLLUTANT STUDY EMISSION TEST REPORT, MAINE ENERGY RECOVERY COMPANY, RE- FUSE DERIVED FUEL FACILITY, BIDDEFORD, MAINE - VOLUME I: SUMMARY OF RESULTS

EPA Science Inventory

The report gives results of an emission test of a new municipal solid waste combustor, in Biddeford, ME, that burns refuse-derived fuel and is equipped with a lime spray dryer fabric filter (SD/FF) emission control system. ontrol efficiency of the SD/FF emission control system wa...

Mercury Emissions Capture Efficiency with Activated Carbon Injection at a Russian Coal-Fired Thermal Power Plant

EPA Science Inventory

This EPA-led project, conducted in collaboration with UNEP, the Swedish Environmental Institute and various Russian Institutes, that demonstrates that the mercury emission control efficiencies of activated carbon injection technologies applied at a Russian power plant burning Rus...

40 CFR 63.53 - Application content for case-by-case MACT determinations.

Code of Federal Regulations, 2012 CFR

2012-07-01

... identified emission point or group of affected emission points, an identification of control technology in... on the design, operation, size, estimated control efficiency and any other information deemed... CATEGORIES Requirements for Control Technology Determinations for Major Sources in Accordance With Clean Air...

40 CFR 63.53 - Application content for case-by-case MACT determinations.

Code of Federal Regulations, 2014 CFR

2014-07-01

... identified emission point or group of affected emission points, an identification of control technology in... on the design, operation, size, estimated control efficiency and any other information deemed... CATEGORIES Requirements for Control Technology Determinations for Major Sources in Accordance With Clean Air...

40 CFR 63.53 - Application content for case-by-case MACT determinations.

Code of Federal Regulations, 2013 CFR

2013-07-01

... identified emission point or group of affected emission points, an identification of control technology in... on the design, operation, size, estimated control efficiency and any other information deemed... CATEGORIES Requirements for Control Technology Determinations for Major Sources in Accordance With Clean Air...

40 CFR 63.53 - Application content for case-by-case MACT determinations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... identified emission point or group of affected emission points, an identification of control technology in... on the design, operation, size, estimated control efficiency and any other information deemed... CATEGORIES Requirements for Control Technology Determinations for Major Sources in Accordance With Clean Air...

How DRB-XCL burners and air heater upgrade reduced NO sub x and improved efficiency at a western utility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Becker, W.; Stalcup, T.; Schild, V.

1992-01-01

The Neil Simpson Unit is a 220,000 lb/hr pulverized coal boiler that was designed to fire a local Wyoming subbituminous coal. During the late 1980s, the Wyoming Department of Air Quality imposed emission limits on the Black Hills Power and Light Co., Neil Simpson Station. The new limits required Black Hills power to control not only particulate and sulfur dioxide (SO{sub 2}) emissions, but also nitrogen oxide (NO{sub x}) emissions. At the same time, Black Hills Power initiated an efficiency improvement study at Neil Simpson Station to investigate methods for reducing net electrical generation costs. This paper addresses the plantmore » efficiency and emissions studies, startup activities, the operating problems and successful operating solutions for NO{sub x} control when firing a Wyoming subbituminous coal. Also included is a summary of the post-0retrofit boiler performance data.« less

Pollutant Emissions and Energy Efficiency under Controlled Conditions for Household Biomass Cookstoves and Implications for Metrics Useful in Setting International Test Standards

EPA Science Inventory

Realistic metrics and methods for testing household biomass cookstoves are required to develop standards needed by international policy makers, donors, and investors. Application of consistent test practices allows emissions and energy efficiency performance to be benchmarked and...

40 CFR Table 3 to Subpart Kkkk of... - Emission Limits for Affected Sources Using the Control Efficiency/Outlet Concentration Compliance...

Code of Federal Regulations, 2013 CFR

2013-07-01

... reconstructed affected source a. reduce emissions of total HAP, measured as THC (as carbon), a by 97 percent; orb. limit emissions of total HAP, measured as THC (as carbon), a to 20 ppmvd at the control device outlet and use a PTE. 2. in an existing affected source a. reduce emissions of total HAP, measured as THC...

40 CFR Table 3 to Subpart Kkkk of... - Emission Limits for Affected Sources Using the Control Efficiency/Outlet Concentration Compliance...

Code of Federal Regulations, 2012 CFR

2012-07-01

... reconstructed affected source a. reduce emissions of total HAP, measured as THC (as carbon), a by 97 percent; orb. limit emissions of total HAP, measured as THC (as carbon), a to 20 ppmvd at the control device outlet and use a PTE. 2. in an existing affected source a. reduce emissions of total HAP, measured as THC...

40 CFR Table 3 to Subpart Kkkk of... - Emission Limits for Affected Sources Using the Control Efficiency/Outlet Concentration Compliance...

Code of Federal Regulations, 2014 CFR

2014-07-01

... reconstructed affected source a. reduce emissions of total HAP, measured as THC (as carbon), a by 97 percent; orb. limit emissions of total HAP, measured as THC (as carbon), a to 20 ppmvd at the control device outlet and use a PTE. 2. in an existing affected source a. reduce emissions of total HAP, measured as THC...

40 CFR Table 3 to Subpart Kkkk of... - Emission Limits for Affected Sources Using the Control Efficiency/Outlet Concentration Compliance...

Code of Federal Regulations, 2011 CFR

2011-07-01

... affected source a. reduce emissions of total HAP, measured as THC (as carbon), a by 97 percent; orb. limit emissions of total HAP, measured as THC (as carbon), a to 20 ppmvd at the control device outlet and use a PTE. 2. in an existing affected source a. reduce emissions of total HAP, measured as THC (as carbon...

40 CFR Table 3 to Subpart Kkkk of... - Emission Limits for Affected Sources Using the Control Efficiency/Outlet Concentration Compliance...

Code of Federal Regulations, 2010 CFR

2010-07-01

... affected source a. reduce emissions of total HAP, measured as THC (as carbon), a by 97 percent; orb. limit emissions of total HAP, measured as THC (as carbon), a to 20 ppmvd at the control device outlet and use a PTE. 2. in an existing affected source a. reduce emissions of total HAP, measured as THC (as carbon...

40 CFR 63.4311 - What reports must I submit?

Code of Federal Regulations, 2010 CFR

2010-07-01

...-on controls, or the organic HAP overall control efficiency compliance option for web coating/printing... emission rate with add-on controls option, the organic HAP overall control efficiency option, or the oxidizer outlet organic HAP concentration option and there were no periods during which the continuous...

Variable emissivity laser thermal control system

DOEpatents

Milner, J.R.

1994-10-25

A laser thermal control system for a metal vapor laser maintains the wall temperature of the laser at a desired level by changing the effective emissivity of the water cooling jacket. This capability increases the overall efficiency of the laser. 8 figs.

COARSE PM EMISSIONS MODEL DEVELOPMENT AND INVENTORY VALIDATION

EPA Science Inventory

The proposed research will contribute to our understanding of the sources and controlling variables of coarse PM. This greater understanding, along with an increase in our ability to predict these emissions, will enable more efficient pollution control strategy development. Ad...

Marginal abatement cost curve for nitrogen oxides incorporating controls, renewable electricity, energy efficiency, and fuel switching.

PubMed

Loughlin, Daniel H; Macpherson, Alexander J; Kaufman, Katherine R; Keaveny, Brian N

2017-10-01

A marginal abatement cost curve (MACC) traces out the relationship between the quantity of pollution abated and the marginal cost of abating each additional unit. In the context of air quality management, MACCs are typically developed by sorting control technologies by their relative cost-effectiveness. Other potentially important abatement measures such as renewable electricity, energy efficiency, and fuel switching (RE/EE/FS) are often not incorporated into MACCs, as it is difficult to quantify their costs and abatement potential. In this paper, a U.S. energy system model is used to develop a MACC for nitrogen oxides (NO x ) that incorporates both traditional controls and these additional measures. The MACC is decomposed by sector, and the relative cost-effectiveness of RE/EE/FS and traditional controls are compared. RE/EE/FS are shown to have the potential to increase emission reductions beyond what is possible when applying traditional controls alone. Furthermore, a portion of RE/EE/FS appear to be cost-competitive with traditional controls. Renewable electricity, energy efficiency, and fuel switching can be cost-competitive with traditional air pollutant controls for abating air pollutant emissions. The application of renewable electricity, energy efficiency, and fuel switching is also shown to have the potential to increase emission reductions beyond what is possible when applying traditional controls alone.

Estimates of increased black carbon emissions from electrostatic precipitators during powdered activated carbon injection for mercury emissions control.

PubMed

Clack, Herek L

2012-07-03

The behavior of mercury sorbents within electrostatic precipitators (ESPs) is not well-understood, despite a decade or more of full-scale testing. Recent laboratory results suggest that powdered activated carbon exhibits somewhat different collection behavior than fly ash in an ESP and particulate filters located at the outlet of ESPs have shown evidence of powdered activated carbon penetration during full-scale tests of sorbent injection for mercury emissions control. The present analysis considers a range of assumed differential ESP collection efficiencies for powdered activated carbon as compared to fly ash. Estimated emission rates of submicrometer powdered activated carbon are compared to estimated emission rates of particulate carbon on submicrometer fly ash, each corresponding to its respective collection efficiency. To the extent that any emitted powdered activated carbon exhibits size and optical characteristics similar to black carbon, such emissions could effectively constitute an increase in black carbon emissions from coal-based stationary power generation. The results reveal that even for the low injection rates associated with chemically impregnated carbons, submicrometer particulate carbon emissions can easily double if the submicrometer fraction of the native fly ash has a low carbon content. Increasing sorbent injection rates, larger collection efficiency differentials as compared to fly ash, and decreasing sorbent particle size all lead to increases in the estimated submicrometer particulate carbon emissions.

Drive cycle simulation of high efficiency combustions on fuel economy and exhaust properties in light-duty vehicles

DOE PAGES

Gao, Zhiming; Curran, Scott J.; Parks, James E.; ...

2015-04-06

We present fuel economy and engine-out emissions for light-duty (LD) conventional and hybrid vehicles powered by conventional and high-efficiency combustion engines. Engine technologies include port fuel-injected (PFI), direct gasoline injection (GDI), reactivity controlled compression ignition (RCCI) and conventional diesel combustion (CDC). In the case of RCCI, the engine utilized CDC combustion at speed/load points not feasible with RCCI. The results, without emissions considered, show that the best fuel economies can be achieved with CDC/RCCI, with CDC/RCCI, CDC-only, and lean GDI all surpassing PFI fuel economy significantly. In all cases, hybridization significantly improved fuel economy. The engine-out hydrocarbon (HC), carbon monoxidemore » (CO), nitrogen oxides (NOx), and particulate matter (PM) emissions varied remarkably with combustion mode. The simulated engine-out CO and HC emissions from RCCI are significantly higher than CDC, but RCCI makes less NOx and PM emissions. Hybridization can improve lean GDI and RCCI cases by increasing time percentage for these more fuel efficient modes. Moreover, hybridization can dramatically decreases the lean GDI and RCCI engine out emissions. Importantly, lean GDI and RCCI combustion modes decrease exhaust temperatures, especially for RCCI, which limits aftertreatment performance to control tailpipe emissions. Overall, the combination of engine and hybrid drivetrain selected greatly affects the emissions challenges required to meet emission regulations.« less

Physical properties of particulate matter (PM) from late model heavy-duty diesel vehicles operating with advanced PM and NO x emission control technologies

NASA Astrophysics Data System (ADS)

Biswas, Subhasis; Hu, Shaohua; Verma, Vishal; Herner, Jorn D.; Robertson, William H.; Ayala, Alberto; Sioutas, Constantinos

Emission control technologies designed to meet the 2007 and 2010 emission standards for heavy-duty diesel vehicles (HDDV) remove effectively the non-volatile fraction of particles, but are comparatively less efficient at controlling the semi-volatile components. A collaborative study between the California Air Resources Board (CARB) and the University of Southern California was initiated to investigate the physicochemical and toxicological characteristics of the semi-volatile and non-volatile particulate matter (PM) fractions from HDDV emissions. This paper reports the physical properties, including size distribution, volatility (in terms of number and mass), surface diameter, and agglomeration of particles emitted from HDDV retrofitted with advanced emission control devices. Four vehicles in combination with six after-treatment devices (V-SCRT ®, Z-SCRT ®, CRT ®, DPX, Hybrid-CCRT ®, EPF) were tested under three driving cycles: steady state (cruise), transient (urban dynamometer driving schedule, UDDS), and idle. An HDDV without any control device is served as the baseline vehicle. Substantial reduction of PM mass emissions (>90%) was accomplished for the HDDV operating with advanced emission control technologies. This reduction was not observed for particle number concentrations under cruise conditions, with the exceptions of the Hybrid-CCRT ® and EPF vehicles, which were efficient in controlling both—mass and number emissions. In general, significant nucleation mode particles (<50 nm) were formed during cruise cycles in comparison with the UDDS cycles, which emit higher PM mass in the accumulation mode. The nucleation mode particles (<50 nm) were mainly internally mixed, and evaporated considerably between 150 and 230 °C. Compared to the baseline vehicle, particles from vehicles with controls (except of the Hybrid-CCRT ®) had a higher mass specific surface area.

Statistical estimate of mercury removal efficiencies for air pollution control devices of municipal solid waste incinerators.

PubMed

Takahashi, Fumitake; Kida, Akiko; Shimaoka, Takayuki

2010-10-15

Although representative removal efficiencies of gaseous mercury for air pollution control devices (APCDs) are important to prepare more reliable atmospheric emission inventories of mercury, they have been still uncertain because they depend sensitively on many factors like the type of APCDs, gas temperature, and mercury speciation. In this study, representative removal efficiencies of gaseous mercury for several types of APCDs of municipal solid waste incineration (MSWI) were offered using a statistical method. 534 data of mercury removal efficiencies for APCDs used in MSWI were collected. APCDs were categorized as fixed-bed absorber (FA), wet scrubber (WS), electrostatic precipitator (ESP), and fabric filter (FF), and their hybrid systems. Data series of all APCD types had Gaussian log-normality. The average removal efficiency with a 95% confidence interval for each APCD was estimated. The FA, WS, and FF with carbon and/or dry sorbent injection systems had 75% to 82% average removal efficiencies. On the other hand, the ESP with/without dry sorbent injection had lower removal efficiencies of up to 22%. The type of dry sorbent injection in the FF system, dry or semi-dry, did not make more than 1% difference to the removal efficiency. The injection of activated carbon and carbon-containing fly ash in the FF system made less than 3% difference. Estimation errors of removal efficiency were especially high for the ESP. The national average of removal efficiency of APCDs in Japanese MSWI plants was estimated on the basis of incineration capacity. Owing to the replacement of old APCDs for dioxin control, the national average removal efficiency increased from 34.5% in 1991 to 92.5% in 2003. This resulted in an additional reduction of about 0.86Mg emission in 2003. Further study using the methodology in this study to other important emission sources like coal-fired power plants will contribute to better emission inventories. Copyright © 2010 Elsevier B.V. All rights reserved.

Low Emissions and Delay Optimization for an Isolated Signalized Intersection Based on Vehicular Trajectories

PubMed Central

2015-01-01

A traditional traffic signal control system is established based on vehicular delay, queue length, saturation and other indicators. However, due to the increasing severity of urban environmental pollution issues and the development of a resource-saving and environmentally friendly social philosophy, the development of low-carbon and energy-efficient urban transport is required. This paper first defines vehicular trajectories and the calculation of vehicular emissions based on VSP. Next, a regression analysis method is used to quantify the relationship between vehicular emissions and delay, and a traffic signal control model is established to reduce emissions and delay using the enumeration method combined with saturation constraints. Finally, one typical intersection of Changchun is selected to verify the model proposed in this paper; its performance efficiency is also compared using simulations in VISSIM. The results of this study show that the proposed model can significantly reduce vehicle delay and traffic emissions simultaneously. PMID:26720095

Low Emissions and Delay Optimization for an Isolated Signalized Intersection Based on Vehicular Trajectories.

PubMed

Lin, Ciyun; Gong, Bowen; Qu, Xin

2015-01-01

A traditional traffic signal control system is established based on vehicular delay, queue length, saturation and other indicators. However, due to the increasing severity of urban environmental pollution issues and the development of a resource-saving and environmentally friendly social philosophy, the development of low-carbon and energy-efficient urban transport is required. This paper first defines vehicular trajectories and the calculation of vehicular emissions based on VSP. Next, a regression analysis method is used to quantify the relationship between vehicular emissions and delay, and a traffic signal control model is established to reduce emissions and delay using the enumeration method combined with saturation constraints. Finally, one typical intersection of Changchun is selected to verify the model proposed in this paper; its performance efficiency is also compared using simulations in VISSIM. The results of this study show that the proposed model can significantly reduce vehicle delay and traffic emissions simultaneously.

40 CFR 63.5170 - How do I demonstrate compliance with the standards?

Code of Federal Regulations, 2011 CFR

2011-07-01

... for individual or groups of coil coating lines; or overall organic HAP control efficiency is at least... compliant coatings and control devices and maintaining an acceptable equivalent emission rate Average... facility. (6) Control efficiency calculation of HAP emitted. For each work station or group of work...

40 CFR 63.5170 - How do I demonstrate compliance with the standards?

Code of Federal Regulations, 2010 CFR

2010-07-01

... for individual or groups of coil coating lines; or overall organic HAP control efficiency is at least... compliant coatings and control devices and maintaining an acceptable equivalent emission rate Average... facility. (6) Control efficiency calculation of HAP emitted. For each work station or group of work...

40 CFR 63.10009 - May I use emissions averaging to comply with this subpart?

Code of Federal Regulations, 2014 CFR

2014-07-01

... performance test must not be less than the design efficiency of the emissions control technology employed 180... properties, belonging to a single major industrial grouping, which are under common control of the same person (or persons under common control); and (ii) You use CEMS (or sorbent trap monitoring systems for...

40 CFR 63.10009 - May I use emissions averaging to comply with this subpart?

Code of Federal Regulations, 2012 CFR

2012-07-01

... performance test must not be less than the design efficiency of the emissions control technology employed 180... properties, belonging to a single major industrial grouping, which are under common control of the same person (or persons under common control); and (ii) You use CEMS (or sorbent trap monitoring systems for...

NOVEL MERCURY OXIDANT AND SORBENT FOR MERCURY EMISSIONS CONTROL FROM COAL-FIRED POWER PLANTS

EPA Science Inventory

The authors have successfully developed novel efficient and cost-effective sorbent and oxidant for removing mercury from power plant flue gases. These sorbent and oxidant offer great promise for controlling mercury emissions from coal-fired power plants burning a wide range of c...

Filter-based control of particulate matter from a lean gasoline direct injection engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parks, II, James E; Lewis Sr, Samuel Arthur; DeBusk, Melanie Moses

New regulations requiring increases in vehicle fuel economy are challenging automotive manufacturers to identify fuel-efficient engines for future vehicles. Lean gasoline direct injection (GDI) engines offer significant increases in fuel efficiency over the more common stoichiometric GDI engines already in the marketplace. However, particulate matter (PM) emissions from lean GDI engines, particularly during stratified combustion modes, are problematic for lean GDI technology to meet U.S. Environmental Protection Agency Tier 3 and other future emission regulations. As such, the control of lean GDI PM with wall-flow filters, referred to as gasoline particulate filter (GPF) technology, is of interest. Since lean GDImore » PM chemistry and morphology differ from diesel PM (where more filtration experience exists), the functionality of GPFs needs to be studied to determine the operating conditions suitable for efficient PM removal. In addition, lean GDI engine exhaust temperatures are generally higher than diesel engines which results in more continuous regeneration of the GPF and less presence of the soot cake layer common to diesel particulate filters. Since the soot layer improves filtration efficiency, this distinction is important to consider. Research on the emission control of PM from a lean GDI engine with a GPF was conducted on an engine dynamometer. PM, after dilution, was characterized with membrane filters, organic vs. elemental carbon characterization, and size distribution techniques at various steady state engine speed and load points. The engine was operated in three primary combustion modes: stoichiometric, lean homogeneous, and lean stratified. In addition, rich combustion was utilized to simulate PM from engine operation during active regeneration of lean NOx control technologies. High (>95%) PM filtration efficiencies were observed over a wide range of conditions; however, some PM was observed to slip through the GPF at high speed and load conditions. The PM characterization at various engine speeds and loads will help enable optimized GPF design and control to achieve more fuel efficient lean GDI vehicles with low PM emissions.« less

Advanced control design for hybrid turboelectric vehicle

NASA Technical Reports Server (NTRS)

Abban, Joseph; Norvell, Johnesta; Momoh, James A.

1995-01-01

The new environment standards are a challenge and opportunity for industry and government who manufacture and operate urban mass transient vehicles. A research investigation to provide control scheme for efficient power management of the vehicle is in progress. Different design requirements using functional analysis and trade studies of alternate power sources and controls have been performed. The design issues include portability, weight and emission/fuel efficiency of induction motor, permanent magnet and battery. A strategic design scheme to manage power requirements using advanced control systems is presented. It exploits fuzzy logic, technology and rule based decision support scheme. The benefits of our study will enhance the economic and technical feasibility of technological needs to provide low emission/fuel efficient urban mass transit bus. The design team includes undergraduate researchers in our department. Sample results using NASA HTEV simulation tool are presented.

A note on calculation of efficiency and emissions from wood and wood pellet stoves

NASA Astrophysics Data System (ADS)

Petrocelli, D.; Lezzi, A. M.

2015-11-01

In recent years, national laws and international regulations have introduced strict limits on efficiency and emissions from woody biomass appliances to promote the diffusion of models characterized by low emissions and high efficiency. The evaluation of efficiency and emissions is made during the certification process which consists in standardized tests. Standards prescribe the procedures to be followed during tests and the relations to be used to determine the mean value of efficiency and emissions. As a matter of fact these values are calculated using flue gas temperature and composition averaged over the whole test period, lasting from 1 to 6 hours. Typically, in wood appliances the fuel burning rate is not constant and this leads to a considerable variation in time of composition and flow rate of the flue gas. In this paper we show that this fact may cause significant differences between emission values calculated according to standards and those obtained integrating over the test period the instantaneous mass and energy balances. In addition, we propose some approximated relations and a method for wood stoves which supply more accurate results than those calculated according to standards. These relations can be easily implemented in a computer controlled data acquisition systems.

Self-organized global control of carbon emissions

NASA Astrophysics Data System (ADS)

Zhao, Zhenyuan; Fenn, Daniel J.; Hui, Pak Ming; Johnson, Neil F.

2010-09-01

There is much disagreement concerning how best to control global carbon emissions. We explore quantitatively how different control schemes affect the collective emission dynamics of a population of emitting entities. We uncover a complex trade-off which arises between average emissions (affecting the global climate), peak pollution levels (affecting citizens’ everyday health), industrial efficiency (affecting the nation’s economy), frequency of institutional intervention (affecting governmental costs), common information (affecting trading behavior) and market volatility (affecting financial stability). Our findings predict that a self-organized free-market approach at the level of a sector, state, country or continent can provide better control than a top-down regulated scheme in terms of market volatility and monthly pollution peaks. The control of volatility also has important implications for any future derivative carbon emissions market.

Aircraft Engine Emissions. [conference

NASA Technical Reports Server (NTRS)

1977-01-01

A conference on a aircraft engine emissions was held to present the results of recent and current work. Such diverse areas as components, controls, energy efficient engine designs, and noise and pollution reduction are discussed.

White polymeric light-emitting diodes with high color rendering index

NASA Astrophysics Data System (ADS)

Niu, Xiaodi; Ma, Liang; Yao, Bing; Ding, Junqiao; Tu, Guoli; Xie, Zhiyuan; Wang, Lixiang

2006-11-01

The efficient white polymeric light-emitting diodes based on a white emissive polymer doped with a red phosphorescent dopant were fabricated by spin-coating method. The emission spectrum of the device is broadened to cover the full visible region by doping the red phosphorescent dye and thereby realizes white emission with high color-rendering index (CRI). By controlling the contents of the doped electron-transporting 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole and the red phosphorescent dopant, a luminous efficiency as high as 5.3cd/A and a power efficiency of 3lm/W were obtained with a CRI of 92.

40 CFR 63.3556 - How do I establish the emission capture system and add-on control device operating limits during...

Code of Federal Regulations, 2013 CFR

2013-07-01

... system and add-on control device operating limits during the performance test? 63.3556 Section 63.3556... of key parameters of the valve operating system (e.g., solenoid valve operation, air pressure... Control Efficiency/outlet Concentration Option § 63.3556 How do I establish the emission capture system...

High efficiency and stable white OLED using a single emitter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Jian

2016-01-18

The ultimate objective of this project was to demonstrate an efficient and stable white OLED using a single emitter on a planar glass substrate. The focus of the project is on the development of efficient and stable square planar phosphorescent emitters and evaluation of such class of materials in the device settings. Key challenges included improving the emission efficiency of molecular dopants and excimers, controlling emission color of emitters and their excimers, and improving optical and electrical stability of emissive dopants. At the end of this research program, the PI has made enough progress to demonstrate the potential of excimer-basedmore » white OLED as a cost-effective solution for WOLED panel in the solid state lighting applications.« less

Combustion Dynamics and Control for Ultra Low Emissions in Aircraft Gas-Turbine Engines

NASA Technical Reports Server (NTRS)

DeLaat, John C.

2011-01-01

Future aircraft engines must provide ultra-low emissions and high efficiency at low cost while maintaining the reliability and operability of present day engines. The demands for increased performance and decreased emissions have resulted in advanced combustor designs that are critically dependent on efficient fuel/air mixing and lean operation. However, all combustors, but most notably lean-burning low-emissions combustors, are susceptible to combustion instabilities. These instabilities are typically caused by the interaction of the fluctuating heat release of the combustion process with naturally occurring acoustic resonances. These interactions can produce large pressure oscillations within the combustor and can reduce component life and potentially lead to premature mechanical failures. Active Combustion Control which consists of feedback-based control of the fuel-air mixing process can provide an approach to achieving acceptable combustor dynamic behavior while minimizing emissions, and thus can provide flexibility during the combustor design process. The NASA Glenn Active Combustion Control Technology activity aims to demonstrate active control in a realistic environment relevant to aircraft engines by providing experiments tied to aircraft gas turbine combustors. The intent is to allow the technology maturity of active combustion control to advance to eventual demonstration in an engine environment. Work at NASA Glenn has shown that active combustion control, utilizing advanced algorithms working through high frequency fuel actuation, can effectively suppress instabilities in a combustor which emulates the instabilities found in an aircraft gas turbine engine. Current efforts are aimed at extending these active control technologies to advanced ultra-low-emissions combustors such as those employing multi-point lean direct injection.

DIESEL ENGINE EFFICIENCY AND EMISSIONS IMPROVEMENT VIA PISTON TEMPERATURE CONTROL - PHASE I

EPA Science Inventory

Model assessment of atmospheric pollution control schemes for critical emission regions

NASA Astrophysics Data System (ADS)

Zhai, Shixian; An, Xingqin; Liu, Zhao; Sun, Zhaobin; Hou, Qing

2016-01-01

In recent years, the atmospheric environment in portions of China has become significantly degraded and the need for emission controls has become urgent. Because more international events are being planned, it is important to implement air quality assurance targeted at significant events held over specific periods of time. This study sets Yanqihu (YQH), Beijing, the location of the 2014 Beijing APEC (Asia-Pacific Economic Cooperation) summit, as the target region. By using the atmospheric inversion model FLEXPART, we determined the sensitive source zones that had the greatest impact on the air quality of the YQH region in November 2012. We then used the air-quality model Models-3/CMAQ and a high-resolution emissions inventory of the Beijing-Tianjian-Hebei region to establish emission reduction tests for the entire source area and for specific sensitive source zones. This was achieved by initiating emission reduction schemes at different ratios and different times. The results showed that initiating a moderate reduction of emissions days prior to a potential event is more beneficial to the air quality of Beijing than initiating a high-strength reduction campaign on the day of the event. The sensitive source zone of Beijing (BJ-Sens) accounts for 54.2% of the total source area of Beijing (BJ), but its reduction effect reaches 89%-100% of the total area, with a reduction efficiency 1.6-1.9 times greater than that of the entire area. The sensitive source zone of Huabei (HuaB-Sens.) only represents 17.6% of the total area of Huabei (HuaB), but its emission reduction effect reaches 59%-97% of the entire area, with a reduction efficiency 4.2-5.5 times greater than that of the total area. The earlier that emission reduction measures are implemented, the greater the effect they have on preventing the transmission of pollutants. In addition, expanding the controlling areas to sensitive provinces and cities around Beijing (HuaB-sens) can significantly accelerate the reduction effects compared to controlling measures only in the Beijing sensitive source zone (BJ-Sens). Therefore, when enacting emission reduction schemes, cooperating with surrounding provinces and cities, as well as narrowing the reduction scope to specific sensitive source zones prior to unfavorable meteorological conditions, can help reduce emissions control costs and improve the efficiency and maneuverability of emission reduction schemes.

Near Zero Emissions at 50 Percent Thermal Efficiency

DOE Office of Scientific and Technical Information (OSTI.GOV)

None, None

2012-12-31

Detroit Diesel Corporation (DDC) has successfully completed a 10 year DOE sponsored heavy-duty truck engine program, hereafter referred to as the NZ-50 program. This program was split into two major phases. The first phase was called Near-Zero Emission at 50 Percent Thermal Efficiency, and was completed in 2007. The second phase was initiated in 2006, and this phase was named Advancements in Engine Combustion Systems to Enable High-Efficiency Clean Combustion for Heavy-Duty Engines. This phase was completed in September, 2010. The key objectives of the NZ-50 program for this first phase were to: Quantify thermal efficiency degradation associated with reductionmore » of engine-out NOx emissions to the 2007 regulated level of ~1.1 g/hp-hr. Implement an integrated analytical/experimental development plan for improving subsystem and component capabilities in support of emerging engine technologies for emissions and thermal efficiency goals of the program. Test prototype subsystem hardware featuring technology enhancements and demonstrate effective application on a multi-cylinder, production feasible heavy-duty engine test-bed. Optimize subsystem components and engine controls (calibration) to demonstrate thermal efficiency that is in compliance with the DOE 2005 Joule milestone, meaning greater than 45% thermal efficiency at 2007 emission levels. Develop technology roadmap for meeting emission regulations of 2010 and beyond while mitigating the associated degradation in engine fuel consumption. Ultimately, develop technical prime-path for meeting the overall goal of the NZ-50 program, i.e., 50% thermal efficiency at 2010 regulated emissions. These objectives were successfully met during the course of the NZ-50 program. The most noteworthy achievements in this program are summarized as follows: Demonstrated technologies through advanced integrated experiments and analysis to achieve the technical objectives of the NZ-50 program with 50.2% equivalent thermal efficiency under EPA 2010 emissions regulations. Experimentally demonstrate brake efficiency of 48.5% at EPA 2010 emission level at single steady-state point. Analytically demonstrated additional brake efficiency benefits using advanced aftertreatment configuration concept and air system enhancement including, but not limited to, turbo-compound, variable valve actuator system, and new cylinder head redesign, thus helping to achieve the final program goals. Experimentally demonstrated EPA 2010 emissions over FTP cycles using advanced integrated engine and aftertreatment system. These aggressive thermal efficiency and emissions results were achieved by applying a robust systems technology development methodology. It used integrated analytical and experimental tools for subsystem component optimization encompassing advanced fuel injection system, increased EGR cooling capacity, combustion process optimization, and advanced aftertreatment technologies. Model based controls employing multiple input and output techniques enabled efficient integration of the various subsystems and ensured optimal performance of each system within the total engine package. . The key objective of the NZ-50 program for the second phase was to explore advancements in engine combustion systems using high-efficiency clean combustion (HECC) techniques to minimize cylinder-out emissions, targeting a 10% efficiency improvement. The most noteworthy achievements in this phase of the program are summarized as follows: Experimentally and analytically evaluated numerous air system improvements related to the turbocharger and variable valve actuation. Some of the items tested proved to be very successful and modifications to the turbine discovered in this program have since been incorporated into production hardware. The combustion system development continued with evaluation of various designs of the 2-step piston bowl. Significant improvements in engine emissions have been obtained, but fuel economy improvements have been tougher to realize. Development of a neural network control system progressed to the point that the system was fully functional and showing significant fuel economy gains in transient engine testing. Development of the QuantLogic injector with the capability of both a hollow cone spray during early injection and conventional diesel injection at later injection timings was undertaken and proved to be problematic. This injector was designed to be a key component in a PCCI combustion system, but this innovative fuel injector required significantly more development effort than this programâ's resources or timing would allow.« less

Life-cycle-assessment of the historical development of air pollution control and energy recovery in waste incineration.

PubMed

Damgaard, Anders; Riber, Christian; Fruergaard, Thilde; Hulgaard, Tore; Christensen, Thomas H

2010-07-01

Incineration of municipal solid waste is a debated waste management technology. In some countries it is the main waste management option whereas in other countries it has been disregarded. The main discussion point on waste incineration is the release of air emissions from the combustion of the waste, but also the energy recovery efficiency has a large importance. The historical development of air pollution control in waste incineration was studied through life-cycle-assessment modelling of eight different air pollution control technologies. The results showed a drastic reduction in the release of air emissions and consequently a significant reduction in the potential environmental impacts of waste incineration. Improvements of a factor 0.85-174 were obtained in the different impact potentials as technology developed from no emission control at all, to the best available emission control technologies of today (2010). The importance of efficient energy recovery was studied through seven different combinations of heat and electricity recovery, which were modelled to substitute energy produced from either coal or natural gas. The best air pollution control technology was used at the incinerator. It was found that when substituting coal based energy production total net savings were obtained in both the standard and toxic impact categories. However, if the substituted energy production was based on natural gas, only the most efficient recovery options yielded net savings with respect to the standard impacts. With regards to the toxic impact categories, emissions from the waste incineration process were always larger than those from the avoided energy production based on natural gas. The results shows that the potential environmental impacts from air emissions have decreased drastically during the last 35 years and that these impacts can be partly or fully offset by recovering energy which otherwise should have been produced from fossil fuels like coal or natural gas. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

International Experience in Developing Low-Emission Combustors for Land-Based, Large Gas-Turbine Units: Mitsubishi Heavy Industries' Equipment

NASA Astrophysics Data System (ADS)

Bulysova, L. A.; Vasil'ev, V. D.; Berne, A. L.; Gutnik, M. N.; Ageev, A. V.

2018-05-01

This is the second paper in a series of publications summarizing the international experience in the development of low-emission combustors (LEC) for land-based, large (above 250 MW) gas-turbine units (GTU). The purpose of this series is to generalize and analyze the approaches used by various manufacturers in designing flowpaths for fuel and air in LECs, managing fuel combustion, and controlling the fuel flow. The efficiency of advanced GTUs can be as high as 43% (with an output of 350-500 MW) while the efficiency of 600-800 MW combined-cycle units with these GTUs can attain 63.5%. These high efficiencies require a compression ratio of 20-24 and a temperature as high as 1600°C at the combustor outlet. Accordingly, the temperature in the combustion zone also rises. All the requirements for the control of harmful emissions from these GTUs are met. All the manufacturers and designers of LECs for modern GTUs encounter similar problems, such as emissions control, combustion instability, and reliable cooling of hot path parts. Methods of their elimination are different and interesting from the standpoint of science and practice. One more essential requirement is that the efficiency and environmental performance indices must be maintained irrespective of the fuel composition or heating value and also in operation at part loads below 40% of rated. This paper deals with Mitsubishi Series M701 GTUs, F, G, or J class, which have gained a good reputation in the power equipment market. A design of a burner for LECs and a control method providing stable low-emission fuel combustion are presented. The advantages and disadvantages of the use of air bypass valves installed in each liner to maintain a nearly constant air to fuel ratio within a wide range of GTU loads are described. Methods for controlling low- and high-frequency combustion instabilities are outlined. Upgrading of the cooling system for the wall of a liner and a transition piece is of great interest. Change over from effusion (or film) cooling to convective steam cooling and convective air cooling has considerably increased the GTU efficiency.

Enhancing SNCR-aided combustion with oxygen addition

DOEpatents

Kobayashi, Hisashi; Wu, Kuang Tsai; Bool, III, Lawrence E.

2004-03-09

NOx emissions from combustion are reduced, NOx reduction efficiency by SNCR is improved, and other efficiencies are realized, by injecting oxygen into a fuel-rich combustion zone under controlled conditions.

Future Automotive Aftertreatment Solutions: The 150°C Challenge Workshop Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zammit, Michael; DiMaggio, Craig L.; Kim, Chang H.

2013-10-15

With future fuel economy standards enacted, the U.S. automotive manufacturers (OEMs) are committed to pursuing a variety of high risk/highly efficient stoichiometric and lean combustion strategies to achieve superior performance. In recognition of this need, the U.S. Department of Energy (DOE) has partnered with domestic automotive manufacturers through U.S. DRIVE to develop these advanced technologies. However, before these advancements can be introduced into the U.S. market, they must also be able to meet increasingly stringent emissions requirements. A significant roadblock to this implementation is the inability of current catalyst and aftertreatment technologies to provide the required activity at the muchmore » lower exhaust temperatures that will accompany highly efficient combustion processes and powertrain strategies. Therefore, the goal of this workshop and report is to create a U.S. DRIVE emission control roadmap that will identify new materials and aftertreatment approaches that offer the potential for 90% conversion of emissions at low temperature (150°C) and are consistent with highly efficient combustion technologies currently under investigation within U.S. DRIVE Advanced Combustion and Emission Control (ACEC) programs.« less

40 CFR 63.745 - Standards: Primer and topcoat application operations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... system requirements. Each control system shall reduce the operation's organic HAP and VOC emissions to... control system that meets or exceeds the efficiency data points in Tables 1 and 2 of this section and is... pollution control system that meets or exceeds the efficiency data points in Tables 3 and 4 of this section...

40 CFR 63.745 - Standards: Primer and topcoat application operations.

Code of Federal Regulations, 2012 CFR

2012-07-01

... system requirements. Each control system shall reduce the operation's organic HAP and VOC emissions to... control system that meets or exceeds the efficiency data points in Tables 1 and 2 of this section and is... pollution control system that meets or exceeds the efficiency data points in Tables 3 and 4 of this section...

40 CFR 63.745 - Standards: Primer and topcoat application operations.

Code of Federal Regulations, 2014 CFR

2014-07-01

... system requirements. Each control system shall reduce the operation's organic HAP and VOC emissions to... control system that meets or exceeds the efficiency data points in Tables 1 and 2 of this section and is... pollution control system that meets or exceeds the efficiency data points in Tables 3 and 4 of this section...

40 CFR 63.745 - Standards: Primer and topcoat application operations.

Code of Federal Regulations, 2013 CFR

2013-07-01

... system requirements. Each control system shall reduce the operation's organic HAP and VOC emissions to... control system that meets or exceeds the efficiency data points in Tables 1 and 2 of this section and is... pollution control system that meets or exceeds the efficiency data points in Tables 3 and 4 of this section...

40 CFR 63.745 - Standards: Primer and topcoat application operations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... system requirements. Each control system shall reduce the operation's organic HAP and VOC emissions to... control system that meets or exceeds the efficiency data points in Tables 1 and 2 of this section and is... pollution control system that meets or exceeds the efficiency data points in Tables 3 and 4 of this section...

Real-world fuel efficiency and exhaust emissions of light-duty diesel vehicles and their correlation with road conditions.

PubMed

Hu, Jingnan; Wu, Ye; Wang, Zhishi; Li, Zhenhua; Zhou, Yu; Wang, Haitao; Bao, Xiaofeng; Hao, Jiming

2012-01-01

The real-world fuel efficiency and exhaust emission profiles of CO, HC and NOx for light-duty diesel vehicles were investigated. Using a portable emissions measurement system, 16 diesel taxies were tested on different roads in Macao and the data were normalized with the vehicle specific power bin method. The 11 Toyota Corolla diesel taxies have very good fuel economy of (5.9 +/- 0.6) L/100 km, while other five diesel taxies showed relatively high values at (8.5 +/- 1.7) L/100 km due to the variation in transmission systems and emission control strategies. Compared to similar Corolla gasoline models, the diesel cars confirmed an advantage of ca. 20% higher fuel efficiency. HC and CO emissions of all the 16 taxies are quite low, with the average at (0.05 +/- 0.02) g/km and (0.38 +/- 0.15) g/km, respectively. The average NOx emission factor of the 11 Corolla taxies is (0.56 +/- 0.17) g/km, about three times higher than their gasoline counterparts. Two of the three Hyundai Sonata taxies, configured with exhaust gas recirculation (EGR) + diesel oxidation catalyst (DOC) emission control strategies, indicated significantly higher NO2 emissions and NO2/NOx ratios than other diesel taxies and consequently trigger a concern of possibly adverse impacts on ozone pollution in urban areas with this technology combination. A clear and similar pattern for fuel consumption and for each of the three gaseous pollutant emissions with various road conditions was identified. To save energy and mitigate CO2 emissions as well as other gaseous pollutant emissions in urban area, traffic planning also needs improvement.

Mercury Emissions Capture Efficiency with Activated Carbon ...

EPA Pesticide Factsheets

This EPA-led project, conducted in collaboration with UNEP, the Swedish Environmental Institute and various Russian Institutes, that demonstrates that the mercury emission control efficiencies of activated carbon injection technologies applied at a Russian power plant burning Russian coals are similar to those found at U.S. plants burning US coals. (The US funding was from funds provided to the EPA by the Department of State pursuant to the Bio-Chemical Redirect Program which engages former Russian (and other former Soviet) weapons scientists in research projects with US collaborators.) Among other things, this report will aid the major task, of developing guidance on best available mercury control technology/best environmental practices (BAT/BEP) for coal-fired power plants, a major source a global anthropogenic emissions. (The new Minamata Convention requires BAT/BEP for new power plants and other major emission sources within five years of treaty ratification.)

An innovative permanent total enclosure for blast cleaning and painting ships in drydock

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garland, C.; Lukey, M.

1997-12-31

This paper describes a new innovative Permanent Total Enclosure, or CAPE system, which encloses and captures emissions from blast cleaning and painting ship hulls in drydock. A description of the modular enclosure towers with unique seals is shown with several figures. The support barge with its environmental control equipment which includes a dust collector, VOC thermal oxidizer, dehumidifier, boiler, heating coils, air flow fans and, system controls is also described. Data measurements from the first two applications rate this system at 100 percent capture efficiency, 99 percent VOC destruction efficiency and 99.9 percent dust collection efficiency. Ships can be blastmore » cleaned and painted using noncompliant paints and meet all state and federal standards for air emissions.« less

Thermal emission from a metamaterial wire medium slab.

PubMed

D'Aguanno, G; Mattiucci, N; Alù, A; Argyropoulos, C; Foreman, J V; Bloemer, M J

2012-04-23

We investigate thermal emission from a metamaterial wire medium embedded in a dielectric host and highlight two different regimes for efficient emission, respectively characterized by broadband emission near the effective plasma frequency of the metamaterial, and by narrow-band resonant emission at the band-edge in the Bragg scattering regime. We discuss how to control the spectral position and relative strength of these two emission mechanisms by varying the geometrical parameters of the proposed metamaterial and its temperature. © 2012 Optical Society of America

Updated atmospheric speciated mercury emissions from iron and steel production in China during 2000-2015

NASA Astrophysics Data System (ADS)

Wu, Qingru; Gao, Wei; Wang, Shuxiao; Hao, Jiming

2017-09-01

Iron and steel production (ISP) is one of the significant atmospheric Hg emission sources in China. Atmospheric mercury (Hg) emissions from ISP during 2000-2015 were estimated by using a technology-based emission factor method. To support the application of this method, databases of Hg concentrations in raw materials, technology development trends, and Hg removal efficiencies of air pollution control devices (APCDs) were constructed through national sampling and literature review. Hg input to ISP increased from 21.6 t in 2000 to 94.5 t in 2015. In the various types of raw materials, coking coal and iron concentrates contributed 35-46 and 25-32 % of the total Hg input. Atmospheric Hg emissions from ISP increased from 11.5 t in 2000 to 32.7 t in 2015 with a peak of 35.6 t in 2013. Pollution control promoted the increase in average Hg removal efficiency, from 47 % in 2000 to 65 % in 2015. During the study period, sinter/pellet plants and blast furnaces were the largest two emission processes. However, emissions from roasting plants and coke ovens cannot be ignored, which accounted for 22-34 % of ISP's emissions. Overall, Hg speciation shifted from 50/44/6 (gaseous elemental Hg (Hg0)/gaseous oxidized Hg (HgII)/particulate-bound Hg (Hgp)) in 2000 to 40/59/1 in 2015, which indicated a higher proportion of Hg deposition around the emission points. Future emissions of ISP were expected to decrease based on the comprehensive consideration crude-steel production, steel scrap utilization, energy saving, and pollution control measures.

Air Pollutant Emissions Projections for the Cement and Steel Industry in China and the Impact of Emissions Control Technologies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hasanbeigi, Ali; Khanna, Nina; Price, Lynn

China’s cement and steel industry accounts for approximately half of the world’s total cement and steel production. These two industries are two of the most energy-intensive and highest carbon dioxide (CO 2)-emitting industries and two of the key industrial contributors to air pollution in China. For example, the cement industry is the largest source of particulate matter (PM) emissions in China, accounting for 40 percent of its industrial PM emissions and 27 percent of its total national PM emissions. The Chinese steel industry contributed to approximately 20 percent of sulfur dioxide (SO 2) emissions and 27 percent of PM emissionsmore » for all key manufacturing industries in China in 2013. In this study, we analyzed and projected the total PM and SO2 emissions from the Chinese cement and steel industry from 2010–2050 under three different scenarios: a Base Case scenario, an Advanced scenario, and an Advanced EOP (end-of-pipe) scenario. We used bottom-up emissions control technologies data and assumptions to project the emissions. In addition, we conducted an economic analysis to estimate the cost for PM emissions reductions in the Chinese cement industry using EOP control technologies, energy efficiency measures, and product change measures. The results of the emissions projection showed that there is not a substantial difference in PM emissions between the Base Case and Advanced scenarios, for both the cement and steel industries. This is mainly because PM emissions in the cement industry caused mainly by production process and not the fuel use. Since our forecast for the cement production in the Base Case and Advanced scenarios are not too different from each other, this results in only a slight difference in PM emissions forecast for these two scenarios. Also, we assumed a similar share and penetration rate of control technologies from 2010 up to 2050 for these two scenarios for the cement and steel industry. However, the Advanced EOP scenario showed significantly lower PM emissions for the cement industry, reaching to 1.7 million tons of PM in 2050, which is less than half of that in the other two scenarios. The Advanced EOP scenario also has the lowest SO2 emissions for the cement industry in China, reaching to 212,000 tons of SO2 in 2050, which is equal to 40 percent of the SO2 emissions in the Advanced scenario and 30 percent of the emissions in the Base Case scenario. The SO2 emission is mainly caused by fuel (coal) burning in cement kiln or steel processes. For the steel industry, the SO2 emissions of the Advanced EOP scenario are significantly lower than the other scenarios, with emissions declining to 323,000 tons in 2050, which is equal to 21 percent and 17 percent of the emissions of Advanced and Base Case scenarios in 2050, respectively. Results of the economic analysis show that for the Chinese cement industry, end-of-pipe PM control technologies have the lowest abatement cost per ton of PM reduced, followed by product change measures and energy efficiency measures, respectively. In summary, in order to meet Chinese national and regional air quality standards, best practice end-of-pipe emissions control technologies must be installed in both cement and steel industry and it must be supplemented by implementation of energy efficiency technologies and reduction of cement and steel production through structural change in industry.« less

Krakow conference on low emissions sources: Proceedings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pierce, B.L.; Butcher, T.A.

1995-12-31

The Krakow Conference on Low Emission Sources presented the information produced and analytical tools developed in the first phase of the Krakow Clean Fossil Fuels and Energy Efficiency Program. This phase included: field testing to provide quantitative data on missions and efficiencies as well as on opportunities for building energy conservation; engineering analysis to determine the costs of implementing pollution control; and incentives analysis to identify actions required to create a market for equipment, fuels, and services needed to reduce pollution. Collectively, these Proceedings contain reports that summarize the above phase one information, present the status of energy system managementmore » in Krakow, provide information on financing pollution control projects in Krakow and elsewhere, and highlight the capabilities and technologies of Polish and American companies that are working to reduce pollution from low emission sources. It is intended that the US reader will find in these Proceedings useful results and plans for control of pollution from low emission sources that are representative of heating systems in central and Eastern Europe. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.« less

Bovine Host Genetic Variation Influences Rumen Microbial Methane Production with Best Selection Criterion for Low Methane Emitting and Efficiently Feed Converting Hosts Based on Metagenomic Gene Abundance

PubMed Central

Roehe, Rainer; Dewhurst, Richard J.; Duthie, Carol-Anne; Rooke, John A.; McKain, Nest; Ross, Dave W.; Hyslop, Jimmy J.; Waterhouse, Anthony; Freeman, Tom C.

2016-01-01

Methane produced by methanogenic archaea in ruminants contributes significantly to anthropogenic greenhouse gas emissions. The host genetic link controlling microbial methane production is unknown and appropriate genetic selection strategies are not developed. We used sire progeny group differences to estimate the host genetic influence on rumen microbial methane production in a factorial experiment consisting of crossbred breed types and diets. Rumen metagenomic profiling was undertaken to investigate links between microbial genes and methane emissions or feed conversion efficiency. Sire progeny groups differed significantly in their methane emissions measured in respiration chambers. Ranking of the sire progeny groups based on methane emissions or relative archaeal abundance was consistent overall and within diet, suggesting that archaeal abundance in ruminal digesta is under host genetic control and can be used to genetically select animals without measuring methane directly. In the metagenomic analysis of rumen contents, we identified 3970 microbial genes of which 20 and 49 genes were significantly associated with methane emissions and feed conversion efficiency respectively. These explained 81% and 86% of the respective variation and were clustered in distinct functional gene networks. Methanogenesis genes (e.g. mcrA and fmdB) were associated with methane emissions, whilst host-microbiome cross talk genes (e.g. TSTA3 and FucI) were associated with feed conversion efficiency. These results strengthen the idea that the host animal controls its own microbiota to a significant extent and open up the implementation of effective breeding strategies using rumen microbial gene abundance as a predictor for difficult-to-measure traits on a large number of hosts. Generally, the results provide a proof of principle to use the relative abundance of microbial genes in the gastrointestinal tract of different species to predict their influence on traits e.g. human metabolism, health and behaviour, as well as to understand the genetic link between host and microbiome. PMID:26891056

Bovine Host Genetic Variation Influences Rumen Microbial Methane Production with Best Selection Criterion for Low Methane Emitting and Efficiently Feed Converting Hosts Based on Metagenomic Gene Abundance.

PubMed

Roehe, Rainer; Dewhurst, Richard J; Duthie, Carol-Anne; Rooke, John A; McKain, Nest; Ross, Dave W; Hyslop, Jimmy J; Waterhouse, Anthony; Freeman, Tom C; Watson, Mick; Wallace, R John

2016-02-01

Methane produced by methanogenic archaea in ruminants contributes significantly to anthropogenic greenhouse gas emissions. The host genetic link controlling microbial methane production is unknown and appropriate genetic selection strategies are not developed. We used sire progeny group differences to estimate the host genetic influence on rumen microbial methane production in a factorial experiment consisting of crossbred breed types and diets. Rumen metagenomic profiling was undertaken to investigate links between microbial genes and methane emissions or feed conversion efficiency. Sire progeny groups differed significantly in their methane emissions measured in respiration chambers. Ranking of the sire progeny groups based on methane emissions or relative archaeal abundance was consistent overall and within diet, suggesting that archaeal abundance in ruminal digesta is under host genetic control and can be used to genetically select animals without measuring methane directly. In the metagenomic analysis of rumen contents, we identified 3970 microbial genes of which 20 and 49 genes were significantly associated with methane emissions and feed conversion efficiency respectively. These explained 81% and 86% of the respective variation and were clustered in distinct functional gene networks. Methanogenesis genes (e.g. mcrA and fmdB) were associated with methane emissions, whilst host-microbiome cross talk genes (e.g. TSTA3 and FucI) were associated with feed conversion efficiency. These results strengthen the idea that the host animal controls its own microbiota to a significant extent and open up the implementation of effective breeding strategies using rumen microbial gene abundance as a predictor for difficult-to-measure traits on a large number of hosts. Generally, the results provide a proof of principle to use the relative abundance of microbial genes in the gastrointestinal tract of different species to predict their influence on traits e.g. human metabolism, health and behaviour, as well as to understand the genetic link between host and microbiome.

Comparison of different vehicle power trains

NASA Astrophysics Data System (ADS)

Mizsey, Peter; Newson, Esmond

Four different alternatives of mobile power train developments (hybrid diesel, fuel cell operating with hydrogen produced on a petrochemical basis, methanol reformer-fuel cell system, gasoline reformer-fuel cell system), are compared with the gasoline internal combustion engine (ICE), for well-to-wheel efficiencies, CO 2 emissions, and investment costs. Although the ICE requires the lowest investment cost, it is not competitive in well-to-wheel efficiencies and less favourable than the above alternatives for CO 2 emissions. The hybrid diesel power train has the highest well-to-wheel efficiency (30%), but its well-to-wheel carbon dioxide emission is similar to that of the fuel cell power train operated with compressed hydrogen produced on a centralised petrochemical basis. This latter case, however, has the advantage over the hybrid diesel power train that the carbon dioxide emission is concentrated and easier to control than the several point-like sources of emissions. Among the five cases studied only the on-board reforming of methanol offers the possibility of using a renewable energy source (biomass).

A systems evaluation on the effectiveness of a catalyst retrofit program in China.

PubMed

Jones, M; Wilson, R; Norbeck, J M; Han, W; Hurley, R; Schuetzle, D

2001-09-01

A low-cost, rare-earth oxide (REO) catalyst has been recommended as part of China's retrofit program for Chinese carbureted vehicles. This study evaluated: (1) the emission reduction efficiency of the REO catalyst during chassis dynamometer testing on the FTP cycle; (2) the effect that fuel properties had on tailpipe emissions and catalyst efficiency; (3) the importance of vehicle premaintenance as part of a retrofit protocol; and (4) the emission reductions obtained following implementation of the program. Results also show that current in-use Chinese noncatalyst, carbureted vehicles operate excessively rich, resulting in extremely high emissions of CO, gaseous toxic compounds, and other non-methane hydrocarbon species (NMHC). Preretrofit maintenance alone has the potential to reduce these emissions by approximately 50%. Dynamometer emission tests showed emissions reductions of >95% for hydrocarbons, CO, and gaseous toxics after retrofit of the REO catalyst. In particular, the relative unit health risk associated with the decrease in emissions of airborne toxic compounds using unleaded Chinese fuel was reduced from 6.33 to 0.30. (Use of low-sulfur California Phase II gasoline rather than current in-use Chinese fuel reduced emissions further.) Following implementation of the program, a follow-up study showed that in-use emissions benefits were considerably less than anticipated, primarily because of poor quality control at the retrofit service centers, a less aggressive preretrofit maintenance procedure, and unauthorized modification to the recommended retrofit control system. Overall results indicate that a carefully controlled retrofit program using REO catalyst technology can reduce emissions significantly. However, well-defined implementation guidelines, and strict adherence to these guidelines are needed to achieve maximum benefits.

Heavy-Duty Low-Temperature and Diesel Combustion & Heavy-Duty Combustion Modeling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Musculus, Mark P.

Regulatory drivers and market demands for lower pollutant emissions, lower carbon dioxide emissions, and lower fuel consumption motivate the development of clean and fuel-efficient engine operating strategies. Most current production engines use a combination of both in-cylinder and exhaust emissions-control strategies to achieve these goals. The emissions and efficiency performance of in-cylinder strategies depend strongly on flow and mixing processes associated with fuel injection. Various diesel engine manufacturers have adopted close-coupled post-injection combustion strategies to both reduce pollutant emissions and to increase engine efficiency for heavy-duty applications, as well as for light- and medium-duty applications. Close-coupled post-injections are typically shortmore » injections that follow a larger main injection in the same cycle after a short dwell, such that the energy conversion efficiency of the post-injection is typical of diesel combustion. Of the various post-injection schedules that have been reported in the literature, effects on exhaust soot vary by roughly an order of magnitude in either direction of increasing or decreasing emissions relative to single injections (O’Connor et al., 2015). While several hypotheses have been offered in the literature to help explain these observations, no clear consensus has been established. For new engines to take full advantage of the benefits that post-injections can offer, the in-cylinder mechanisms that affect emissions and efficiency must be identified and described to provide guidance for engine design.« less

DRIVE CYCLE EFFICIENCY AND EMISSIONS ESTIMATES FOR REACTIVITY CONTROLLED COMPRESSION IGNITION IN A MULTI-CYLINDER LIGHT-DUTY DIESEL ENGINE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Curran, Scott; Briggs, Thomas E; Cho, Kukwon

2011-01-01

In-cylinder blending of gasoline and diesel to achieve Reactivity Controlled Compression Ignition (RCCI) has been shown to reduce NOx and PM emissions while maintaining or improving brake thermal efficiency as compared to conventional diesel combustion (CDC). The RCCI concept has an advantage over many advanced combustion strategies in that by varying both the percent of premixed gasoline and EGR rate, stable combustion can be extended over more of the light-duty drive cycle load range. Changing the percent premixed gasoline changes the fuel reactivity stratification in the cylinder providing further control of combustion phasing and pressure rise rate than the usemore » of EGR alone. This paper examines the combustion and emissions performance of light-duty diesel engine using direct injected diesel fuel and port injected gasoline to carry out RCCI for steady-state engine conditions which are consistent with a light-duty drive cycle. A GM 1.9L four-cylinder engine with the stock compression ratio of 17.5:1, common rail diesel injection system, high-pressure EGR system and variable geometry turbocharger was modified to allow for port fuel injection with gasoline. Engine-out emissions, engine performance and combustion behavior for RCCI operation is compared against both CDC and a premixed charge compression ignition (PCCI) strategy which relies on high levels of EGR dilution. The effect of percent of premixed gasoline, EGR rate, boost level, intake mixture temperature, combustion phasing and pressure rise rate is investigated for RCCI combustion for the light-duty modal points. Engine-out emissions of NOx and PM were found to be considerably lower for RCCI operation as compared to CDC and PCCI, while HC and CO emissions were higher. Brake thermal efficiency was similar or higher for many of the modal conditions for RCCI operation. The emissions results are used to estimate hot-start FTP-75 emissions levels with RCCI and are compared against CDC and PCCI modes.« less

Role of sectoral and multi-pollutant emission control strategies in improving atmospheric visibility in the Yangtze River Delta, China.

PubMed

Huang, Kan; Fu, Joshua S; Gao, Yang; Dong, Xinyi; Zhuang, Guoshun; Lin, Yanfen

2014-01-01

The Community Multi-scale Air Quality modeling system is used to investigate the response of atmospheric visibility to the emission reduction from different sectors (i.e. industries, traffic and power plants) in the Yangtze River Delta, China. Visibility improvement from exclusive reduction of NOx or VOC emission was most inefficient. Sulfate and organic aerosol would rebound if NOx emission was exclusively reduced from any emission sector. The most efficient way to improve the atmospheric visibility was proven to be the multi-pollutant control strategies. Simultaneous emission reductions (20-50%) on NOx, VOC and PM from the industrial and mobile sectors could result in 0.3-1.0 km visibility improvement. And the emission controls on both NOx (85%) and SO2 (90%) from power plants gained the largest visibility improvement of up to 4.0 km among all the scenarios. The seasonal visibility improvement subject to emission controls was higher in summer while lower in the other seasons. Copyright © 2013 Elsevier Ltd. All rights reserved.

Using Wet-FGD systems for mercury removal.

PubMed

Díaz-Somoano, Mercedes; Unterberger, Sven; Hein, Klaus R G

2005-09-01

A plan to control mercury emissions to the atmosphere and to establish mercury emission limits has recently been elaborated by the European Commission, making it necessary to devise an efficient and cost effective mercury removal technology. Towards this end wet flue gas desulfurization units appear as a promising option for multi-pollutant control. However, more investigation on mercury removal and a greater mercury removal efficiency are required to achieve this objective. In the present work scrubber chemistry and the application of various solid additives to enhance mercury removal in wet scrubbers is evaluated. The results obtained show a significant correlation between mercury removal efficiency and the pH of the scrubber slurry and SO2 concentration. A weaker correlation was observed between oxygen or slurry concentration and removal efficiency. Finally several solid oxides were found to be effective additives for enhancing mercury capture in wet scrubbers.

Removal of viable bioaerosol particles with a low-efficiency HVAC filter enhanced by continuous emission of unipolar air ions.

PubMed

Huang, R; Agranovski, I; Pyankov, O; Grinshpun, S

2008-04-01

Continuous emission of unipolar ions has been shown to improve the performance of respirators and stationary filters challenged with non-biological particles. In this study, we investigated the ion-induced enhancement effect while challenging a low-efficiency heating, ventilation and air-conditioning (HVAC) filter with viable bacterial cells, bacterial and fungal spores, and viruses. The aerosol concentration was measured in real time. Samples were also collected with a bioaerosol sampler for viable microbial analysis. The removal efficiency of the filter was determined, respectively, with and without an ion emitter. The ionization was found to significantly enhance the filter efficiency in removing viable biological particles from the airflow. For example, when challenged with viable bacteria, the filter efficiency increased as much as four- to fivefold. For viable fungal spores, the ion-induced enhancement improved the efficiency by a factor of approximately 2. When testing with virus-carrying liquid droplets, the original removal efficiency provided by the filter was rather low: 9.09 +/- 4.84%. While the ion emission increased collection about fourfold, the efficiency did not reach 75-100% observed with bacteria and fungi. These findings, together with our previously published results for non-biological particles, demonstrate the feasibility of a new approach for reducing aerosol particles in HVAC systems used for indoor air quality control. Recirculated air in HVAC systems used for indoor air quality control in buildings often contains considerable number of viable bioaerosol particles because of limited efficiency of the filters installed in these systems. In the present study, we investigated - using aerosolized bacterial cells, bacterial and fungal spores, and virus-carrying particles - a novel idea of enhancing the performance of a low-efficiency HVAC filter utilizing continuous emission of unipolar ions in the filter vicinity. The findings described in this paper, together with our previously published results for non-biological particles, demonstrate the feasibility of the newly developed approach.

Intermittent micro-aeration control of methane emissions from an integrated vertical-flow constructed wetland during agricultural domestic wastewater treatment.

PubMed

Liu, Xiaoling; Zhang, Ke; Fan, Liangqian; Luo, Hongbing; Jiang, Mingshu; Anderson, Bruce C; Li, Mei; Huang, Bo; Yu, Lijuan; He, Guozhu; Wang, Jingting; Pu, Aiping

2018-06-16

It is very important to control methane emissions to mitigate global warming. An intermittent micro-aeration control system was used to control methane emissions from an integrated vertical-flow constructed wetland (IVCW) to treat agricultural domestic wastewater pollution in this study. The optimized intermittent micro-aeration conditions were a 20-min aeration time and 340-min non-aeration time, 3.9 m 3  h -1 aeration intensity, evenly distributed micro-aeration diffusers at the tank bottom, and an aeration period of every 6 h. Methane flux emission by intermittent micro-aeration was decreased by 60.7% under the optimized conditions. The average oxygen transfer efficiency was 26.73%. The control of CH 4 emission from IVCWs was most strongly influenced by the intermittent micro-aeration diffuser distribution, followed by aeration intensity, aeration time, and water depth. Scaling up of IVCWs is feasible in rural areas by using intermittent micro-aeration control as a mitigation measure for methane gas emissions for climate change.

Coordinated EV adoption: double-digit reductions in emissions and fuel use for $40/vehicle-year.

PubMed

Choi, Dong Gu; Kreikebaum, Frank; Thomas, Valerie M; Divan, Deepak

2013-09-17

Adoption of electric vehicles (EVs) would affect the costs and sources of electricity and the United States efficiency requirements for conventional vehicles (CVs). We model EV adoption scenarios in each of six regions of the Eastern Interconnection, containing 70% of the United States population. We develop electricity system optimization models at the multidecade, day-ahead, and hour-ahead time scales, incorporating spatial wind energy modeling, endogenous modeling of CV efficiencies, projections for EV efficiencies, and projected CV and EV costs. We find two means to reduce total consumer expenditure (TCE): (i) controlling charge timing and (ii) unlinking the fuel economy regulations for CVs from EVs. Although EVs provide minimal direct GHG reductions, controlled charging provides load flexibility, lowering the cost of renewable electricity. Without EVs, a 33% renewable electricity standard (RES) would cost $193/vehicle-year more than the reference case (10% RES). Combining a 33% RES, EVs with controlled charging and unlinking would reduce combined electric- and vehicle-sector CO2 emissions by 27% and reduce gasoline consumption by 59% for $40/vehicle-year more than the reference case. Coordinating EV adoption with adoption of controlled charging, unlinked fuel economy regulations, and renewable electricity standards would provide low-cost reductions in emissions and fuel usage.

Heating boilers in Krakow, Poland: Options for improving efficiency and reducing emissions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cyklis, P.; Kowalski, J.; Kroll, J.

1995-08-01

In Krakow, Poland, coal-fired boilers are used to heat single apartment buildings and local heating districts. The population includes 2,930 small, hand-fired boilers and 227 larger traveling grate stoker-fired boilers. These boilers are important contributors to air quality problems in Krakow, and an assessment of their efficiency and emissions characteristics was recently undertaken. For the larger, stoker-fired boilers, efficiency was measured using a stack-loss method. In addition to the normal baseline fuel, the effects of coal cleaning and grading were evaluated. Testing was done at two selected sites. Boiler efficiencies were found to be low--50% to 67%. These boilers operatemore » without combustion controls or instrumentation for flue gas analysis. As a result, excess air levels are very high--up to 400%--leading to poor performance. Emissions were found to be typical for boilers of this type. Using the improved fuels yields reductions in emissions and improvement in efficiency when combined with proper adjustments. In the case of the hand-fired boilers, one set of cast-iron boilers and one set of steel boilers were tested. Efficiency in this case was measured using an input-output method for sets of three boilers taken together as a system. Emissions from these boilers are lowest when low volatile fuels, such as coke or smokeless briquettes, are used.« less

40 CFR 63.4965 - How do I determine the add-on control device emission destruction or removal efficiency?

Code of Federal Regulations, 2010 CFR

2010-07-01

... an alternative to Method 3B, the manual method for measuring the oxygen, carbon dioxide, and carbon..., Instruments and Apparatus]” (incorporated by reference, see § 63.14). (4) Use Method 4 of appendix A to 40 CFR... total gaseous organic mass emissions as carbon at the inlet and outlet of the add-on control device...

40 CFR 63.3545 - How do I determine the add-on control device emission destruction or removal efficiency?

Code of Federal Regulations, 2010 CFR

2010-07-01

... an alternative to Method 3B the manual method for measuring the oxygen, carbon dioxide, and carbon..., Instruments and Apparatus]” (incorporated by reference, see § 63.14). (4) Use Method 4 of appendix A to 40 CFR... total gaseous organic mass emissions as carbon at the inlet and outlet of the add-on control device...

Manganese-Doped One-Dimensional Organic Lead Bromide Perovskites with Bright White Emissions.

PubMed

Zhou, Chenkun; Tian, Yu; Khabou, Oussama; Worku, Michael; Zhou, Yan; Hurley, Joseph; Lin, Haoran; Ma, Biwu

2017-11-22

Single-component white-emitting phosphors are highly promising to simplify the fabrication of optically pumped white light-emitting diodes. To achieve white emission, precise control of the excited state dynamics is required for a single-component system to generate emissions with different energies in the steady state. Here, we report a new class of white phosphors based on manganese (Mn)-doped one-dimensional (1D) organic lead bromide perovskites. The bright white emission is the combination of broadband blue emission from the self-trapped excited states of the 1D perovskites and red emission from the doped Mn 2+ ions. Because of the indirect nature of the self-trapped excited states in 1D perovskites, there is no energy transfer from these states to the Mn 2+ ions, resulting in an efficient dual emission. As compared to the pristine 1D perovskites with bluish-white emission, these Mn-doped 1D perovskites exhibit much higher color rendering index of up to 87 and photoluminescence quantum efficiency of up to 28%.

[Research advances in control of N2O emission from municipal solid waste landfill sites].

PubMed

Cai, Chuan-Yu; Li, Bo; Lü, Hao-Hao; Wu, Wei-Xiang

2012-05-01

Landfill is one of the main approaches for municipal solid waste treatment, and landfill site is a main emission source of greenhouse gases nitrous oxide (N2O) and methane (CH4). As a high-efficient trace greenhouse gas, N2O has a very high warming potential, with a warming capacity 296 times of CO2, and has a long-term stability in atmosphere, giving greater damage to the ozone layer. Aiming at the researches in the control of N2O emission from municipal solid waste landfill sites, this paper summarized the characteristics and related affecting factors of the N2O emission from the landfill sites, and put forward a series of the measures adaptable to the N2O emission control of present municipal solid waste landfill sites in China. Some further research focuses on the control of N2O emission from the landfill sites were also presented.

Heavy-Duty Stoichiometric Compression Ignition Engine with Improved Fuel Economy over Alternative Technologies for Meeting 2010 On-Highway Emission

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kirby J. Baumgard; Richard E. Winsor

2009-12-31

The objectives of the reported work were: to apply the stoichiometric compression ignition (SCI) concept to a 9.0 liter diesel engine; to obtain engine-out NO{sub x} and PM exhaust emissions so that the engine can meet 2010 on-highway emission standards by applying a three-way catalyst for NO{sub x} control and a particulate filter for PM control; and to simulate an optimize the engine and air system to approach 50% thermal efficiency using variable valve actuation and electric turbo compounding. The work demonstrated that an advanced diesel engine can be operated at stoichiometric conditions with reasonable particulate and NOx emissions atmore » full power and peak torque conditions; calculated that the SCI engine will operate at 42% brake thermal efficiency without advanced hardware, turbocompounding, or waste heat recovery; and determined that EGR is not necessary for this advanced concept engine, and this greatly simplifies the concept.« less

Prospects for energy efficiency improvement and reduction of emissions and life cycle costs for natural gas vehicles

NASA Astrophysics Data System (ADS)

Kozlov, A. V.; Terenchenko, A. S.; Luksho, V. A.; Karpukhin, K. E.

2017-01-01

This work is devoted to the experimental investigation of the possibilities to reduce greenhouse gas emissions and to increase energy efficiency of engines that use natural gas as the main fuel and the analysis of economic efficiency of use of dual fuel engines in vehicles compared to conventional diesel. The results of experimental investigation of a 190 kW dual-fuel engine are presented; it is shown that quantitative and qualitative working process control may ensure thermal efficiency at the same level as that of the diesel engine and in certain conditions 5...8% higher. The prospects for reduction of greenhouse gas emissions have been assessed. The technical and economic evaluation of use of dual fuel engines in heavy-duty vehicles has been performed, taking into account the total life cycle. It is shown that it is possible to reduce life cycle costs by two times.

Polarization control of spontaneous emission for rapid quantum-state initialization

NASA Astrophysics Data System (ADS)

DiLoreto, C. S.; Rangan, C.

2017-04-01

We propose an efficient method to selectively enhance the spontaneous emission rate of a quantum system by changing the polarization of an incident control field, and exploiting the polarization dependence of the system's spontaneous emission rate. This differs from the usual Purcell enhancement of spontaneous emission rates as it can be selectively turned on and off. Using a three-level Λ system in a quantum dot placed in between two silver nanoparticles and a linearly polarized, monochromatic driving field, we present a protocol for rapid quantum state initialization, while maintaining long coherence times for control operations. This process increases the overall amount of time that a quantum system can be effectively utilized for quantum operations, and presents a key advance in quantum computing.

Color control through FRET efficiency modulation using CDI (Conference Presentation)

NASA Astrophysics Data System (ADS)

Wolowelsky, Karni; Guyes, Eric; Rubin, Shimon; Suss, Matthew; Bercovici, Moran; Rotschild, Carmel

2017-02-01

Although much progress was made in light emitting devices, the ability to electrically control their spectral emission remains limited. We will present a novel approach and experimental results for dynamic color control, by electrically modulating the non-radiative Forster resonance energy transfer (FRET) efficiency between donor and acceptor dyes in a solution. FRET efficiency depends on the 6th power of the distance between donor and acceptor dye molecules, and thus, it is sensitive to variations in acceptor's concentration. Controlled acceptor concentrations could be achieved by attracting or repelling ionic dyes from the electrodes using a capacitive deionization (CDI) cell, with high surface area porous electrodes. This approach to dynamic color control may open new directions in 100% fill-factor displays, and can be expanded to energy saving applications such as controlling building's external wall emissivity. We studied the modulation of a single dye emission using a CDI cell with negatively charged Fluorescein Sodium Salt in aquatic solution. Photoluminescence was measured along few charging-discharging CDI cycles and showed the ability to control extensive optical response through CDI. We experimented with two types of FRET-pair dyes: a) anion-cation, where the acceptor and the donor ions are oppositely charged, and b) zwitterion and ion, where the donor is neutral. We found that electrical control on FRET in aquatic solution is weak, due to hydrophobic attractive interaction between the acceptor and the donor. In order to avoid this effect, we are experimenting FRET control in organic solvents. These results will be presented in the talk.

Comparative Study of Hybrid Powertrains on Fuel Saving, Emissions, and Component Energy Loss in HD Trucks

DOE PAGES

Gao, Zhiming; Finney, Charles; Daw, Charles; ...

2014-09-30

We compared parallel and series hybrid powertrains on fuel economy, component energy loss, and emissions control in Class 8 trucks over both city and highway driving. A comprehensive set of component models describing battery energy, engine fuel efficiency, emissions control, and power demand interactions for heavy duty (HD) hybrids has been integrated with parallel and series hybrid Class 8 trucks in order to identify the technical barriers of these hybrid powertrain technologies. The results show that series hybrid is absolutely negative for fuel economy benefit of long-haul trucks due to an efficiency penalty associated with the dual-step conversions of energymore » (i.e. mechanical to electric to mechanical). The current parallel hybrid technology combined with 50% auxiliary load reduction could elevate 5-7% fuel economy of long-haul trucks, but a profound improvement of long-haul truck fuel economy requires additional innovative technologies for reducing aerodynamic drag and rolling resistance losses. The simulated emissions control indicates that hybrid trucks reduce more CO and HC emissions than conventional trucks. The simulated results further indicate that the catalyzed DPF played an important role in CO oxidations. Limited NH 3 emissions could be slipped from the Urea SCR, but the average NH 3 emissions are below 20 ppm. Meanwhile our estimations show 1.5-1.9% of equivalent fuel-cost penalty due to urea consumption in the simulated SCR cases.« less

After 'dieselgate': Regulations or economic incentives for a successful environmental policy?

NASA Astrophysics Data System (ADS)

Zachariadis, Theodoros

2016-08-01

In September 2015 the U.S. Environmental Protection Agency announced that it started investigations against the automaker Volkswagen for illegally installing software that allowed some diesel-powered vehicle models to pass stringent emission tests for type-approval. Although generally prohibited, modern software makes it feasible for vehicles to detect an emission test and modulate engine operation or emission control accordingly. It has also been well known to experts worldwide - and readers of this Journal - that emission tests for motor vehicles are conducted with outdated test procedures which do not reflect today's actual driving conditions and enable automakers to exploit 'flexibilities' so as to yield artificially low emission results. For example, on-road carbon dioxide (CO2) emissions of cars that entered the European market in 2014 were reportedly 40% higher than their formal test emissions, while this gap was less than 10% in the early 2000s (Tietge et al., 2015). In the case of health-related pollutant nitrogen oxides (NOx), this gap seems to be markedly higher, in particular for diesel-powered cars (Weiss et al., 2012) - whereas this does not seem to be a serious problem for other air pollutants. In internal combustion engines of motor vehicles there is still a trade-off between NOx emissions and fuel efficiency (and hence CO2 emissions): a fast combustion with high temperatures is optimal for maximum fuel efficiency and minimum CO2 emissions, whereas these conditions give rise to higher NOx emissions. Conversely, NOx control techniques such as exhaust gas recirculation reduce combustion temperature and often lead to lower fuel efficiency. In short, it becomes ever more difficult for internal combustion engines to meet the increasingly stringent legislated standards for some air pollutants and carbon dioxide at the same time. This increases the probability of applying legal and illegal defeat strategies.

Performance and Exhaust Emissions in a Natural-Gas Fueled Dual-Fuel Engine

NASA Astrophysics Data System (ADS)

Shioji, Masahiro; Ishiyama, Takuji; Ikegami, Makoto; Mitani, Shinichi; Shibata, Hiroaki

In order to establish the optimum fueling in a natural gas fueled dual fuel engine, experiments were done for some operational parameters on the engine performances and the exhaust emissions. The results show that the pilot fuel quantity should be increased and its injection timing should be advanced to suppress unburned hydrocarbon emission in the middle and low output range, while the quantity should be reduced and the timing retarded to avoid onset of knock at high loads. Unburned hydrocarbon emission and thermal efficiency are improved by avoiding too lean natural gas mixture by restricting intake charge air. However, the improvement is limited because the ignition of pilot fuel deteriorates with excessive throttling. It is concluded that an adequate combination of throttle control and equivalence ratio ensures low hydrocarbon emission and the thermal efficiency comparable to diesel operation.

Fugitive dust emission source profiles and assessment of selected control strategies for particulate matter at gravel processing sites in Taiwan.

PubMed

Chang, Chang-Tang; Chang, Yu-Min; Lin, Wen-Yinn; Wu, Ming-Ching

2010-10-01

Particles emitted from gravel processing sites are one contributor to worsening air quality in Taiwan. Major pollution sources at gravel processing sites include gravel and sand piles, unpaved roads, material crushers, and bare ground. This study analyzed fugitive dust emission characteristics at each pollution source using several types of particle samplers, including total suspended particulates (TSP), suspended particulate (PM10), fine suspended particulate (PM2.5), particulate sizer, and dust-fall collectors. Furthermore, silt content and moisture in the gravel were measured to develop particulate emission factors. The results showed that TSP (< 100 microm) concentrations at the boundary of gravel sites ranged from 280 to 1290 microg/m3, which clearly exceeds the Taiwan hourly air quality standard of 500 microg/m3. Moreover, PM10 concentrations, ranging from 135 to 550 microg/m3, were also above the daily air quality standard of 125 microg/m3 and approximately 1.2 and 1.5 times the PM2.5 concentrations, ranging from 105 to 470 microg/m3. The size distribution analysis reveals that mass mean diameter and geometric standard deviation ranged from 3.2 to 5.7 microm and from 2.82 to 5.51, respectively. In this study, spraying surfactant was the most effective control strategy to abate windblown dust from unpaved roads, having a control efficiency of approximately 93%, which is significantly higher than using paved road strategies with a control efficiency of approximately 45%. For paved roads, wet suppression provided the best dust control efficiencies ranging from 50 to 83%. Re-vegetation of disturbed ground had dust control efficiencies ranging from 48 to 64%.

Effects of regional temperature on electric vehicle efficiency, range, and emissions in the United States.

PubMed

Yuksel, Tugce; Michalek, Jeremy J

2015-03-17

We characterize the effect of regional temperature differences on battery electric vehicle (BEV) efficiency, range, and use-phase power plant CO2 emissions in the U.S. The efficiency of a BEV varies with ambient temperature due to battery efficiency and cabin climate control. We find that annual energy consumption of BEVs can increase by an average of 15% in the Upper Midwest or in the Southwest compared to the Pacific Coast due to temperature differences. Greenhouse gas (GHG) emissions from BEVs vary primarily with marginal regional grid mix, which has three times the GHG intensity in the Upper Midwest as on the Pacific Coast. However, even within a grid region, BEV emissions vary by up to 22% due to spatial and temporal ambient temperature variation and its implications for vehicle efficiency and charging duration and timing. Cold climate regions also encounter days with substantial reduction in EV range: the average range of a Nissan Leaf on the coldest day of the year drops from 70 miles on the Pacific Coast to less than 45 miles in the Upper Midwest. These regional differences are large enough to affect adoption patterns and energy and environmental implications of BEVs relative to alternatives.

EVALUATION OF ENGINEERING CONTROLS FOR THE MIXING OF FLAVORINGS CONTAINING DIACETYL AND OTHER VOLATILE INGREDIENTS

PubMed Central

Hirst, Deborah V.L.; Dunn, Kevin H.; Shulman, Stanley A.; Hammond, Duane R.; Sestito, Nicholas

2015-01-01

Exposures to diacetyl, a primary ingredient of butter flavoring, have been shown to cause respiratory disease among workers who mix flavorings. This study focused on evaluating ventilation controls designed to reduce emissions from the flavor mixing tanks, the major source of diacetyl in the plants. Five exhaust hood configurations were evaluated in the laboratory: standard hinged lid-opened, standard hinged lid-closed, hinged lid-slotted, dome with 38-mm gap, and dome with 114-mm gap. Tracer gas tests were performed to evaluate quantitative capture efficiency for each hood. A perforated copper coil was used to simulate an area source within the 1.2-meter diameter mixing tank. Capture efficiencies were measured at four hood exhaust flow rates (2.83, 5.66, 11.3, and 17.0 cubic meters per minute) and three cross draft velocities (0, 30, and 60 meters per minute). All hoods evaluated performed well with capture efficiencies above 90% for most combinations of exhaust volume and cross drafts. The standard hinged lid was the least expensive to manufacture and had the best average capture efficiency (over 99%) in the closed configuration for all exhaust flow rates and cross drafts. The hinged lid-slotted hood had some of the lowest capture efficiencies at the low exhaust flow rates compared to the other hood designs. The standard hinged lid performed well, even in the open position, and it provided a flexible approach to controlling emissions from mixing tanks. The dome hood gave results comparable to the standard hinged lid but it is more expensive to manufacture. The results of the study indicate that emissions from mixing tanks used in the production of flavorings can be controlled using simple inexpensive exhaust hoods. PMID:24649880

Los Alamos National Security, LLC Request for Information on how industry may partner with the Laboratory on KIVA software.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mcdonald, Kathleen Herrera

2016-02-29

KIVA is a family of Fortran-based computational fluid dynamics software developed by LANL. The software predicts complex fuel and air flows as well as ignition, combustion, and pollutant-formation processes in engines. The KIVA models have been used to understand combustion chemistry processes, such as auto-ignition of fuels, and to optimize diesel engines for high efficiency and low emissions. Fuel economy is heavily dependent upon engine efficiency, which in turn depends to a large degree on how fuel is burned within the cylinders of the engine. Higher in-cylinder pressures and temperatures lead to increased fuel economy, but they also create moremore » difficulty in controlling the combustion process. Poorly controlled and incomplete combustion can cause higher levels of emissions and lower engine efficiencies.« less

Time-Resolved Stark Spectroscopy in CdSe Nanoplatelets: Exciton Binding Energy, Polarizability, and Field-Dependent Radiative Rates.

PubMed

Scott, Riccardo; Achtstein, Alexander W; Prudnikau, Anatol V; Antanovich, Artsiom; Siebbeles, Laurens D A; Artemyev, Mikhail; Woggon, Ulrike

2016-10-12

We present a study of the application potential of CdSe nanoplatelets (NPLs), a model system for colloidal 2D materials, as field-controlled emitters. We demonstrate that their emission can be changed by 28% upon application of electrical fields up to 175 kV/cm, a very high modulation depth for field-controlled nanoemitters. From our experimental results we estimate the exciton binding energy in 5.5 monolayer CdSe nanoplatelets to be E B = 170 meV; hence CdSe NPLs exhibit highly robust excitons which are stable even at room temperature. This opens up the possibility to tune the emission and recombination dynamics efficiently by external fields. Our analysis further allows a quantitative discrimination of spectral changes of the emission energy and changes in PL intensity related to broadening of the emission line width as well as changes in the intrinsic radiative rates which are directly connected to the measured changes in the PL decay dynamics. With the developed field-dependent population model treating all occurring field-dependent effects in a global analysis, we are able to quantify, e.g., the ground state exciton transition dipole moment (3.0 × 10 -29 Cm) and its polarizability, which determine the radiative rate, as well as the (static) exciton polarizability (8.6 × 10 -8 eV cm 2 /kV 2 ), all in good agreement with theory. Our results show that an efficient field control over the exciton recombination dynamics, emission line width, and emission energy in these nanoparticles is feasible and opens up application potential as field-controlled emitters.

77 FR 488 - Control of Emissions From New Highway Vehicles and Engines; Approval of New Scheduled Maintenance...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-05

... and engine manufacturers began planning to meet those requirements by optimizing engine designs for low emissions and adding high-efficiency aftertreatment systems. Manufacturers examined the use of... recirculation, and selective catalytic reduction (SCR). SCR systems use a nitrogen-containing reducing agent...

40 CFR 61.10 - Source reporting and waiver request.

Code of Federal Regulations, 2010 CFR

2010-07-01

... control equipment for each emission point including— (i) Each control device for each hazardous pollutant; and (ii) Estimated control efficiency (percent) for each control device. (7) A statement by the owner... 60 or part 63 standard, whichever is latest. Procedures governing the implementation of this...

Optical diagnostics in gas turbine combustors

NASA Astrophysics Data System (ADS)

Woodruff, Steven D.

1999-01-01

Deregulation of the power industry and increasingly tight emission controls are pushing gas turbine manufacturers to develop engines operating at high pressure for efficiency and lean fuel mixtures to control NOx. This combination also gives rise to combustion instabilities which threaten engine integrity through acoustic pressure oscillations and flashback. High speed imaging and OH emission sensors have been demonstrated to be invaluable tools in characterizing and monitoring unstable combustion processes. Asynchronous imaging technique permit detailed viewing of cyclic flame structure in an acoustic environment which may be modeled or utilized in burner design . The response of the flame front to the acoustic pressure cycle may be tracked with an OH emission monitor using a sapphire light pipe for optical access. The OH optical emission can be correlated to pressure sensor data for better understanding of the acoustical coupling of the flame. Active control f the combustion cycle can be implemented using an OH emission sensor for feedback.

Economic growth and carbon emission control

NASA Astrophysics Data System (ADS)

Zhang, Zhenyu

The question about whether environmental improvement is compatible with continued economic growth remains unclear and requires further study in a specific context. This study intends to provide insight on the potential for carbon emissions control in the absence of international agreement, and connect the empirical analysis with theoretical framework. The Chinese electricity generation sector is used as a case study to demonstrate the problem. Both social planner and private problems are examined to derive the conditions that define the optimal level of production and pollution. The private problem will be demonstrated under the emission regulation using an emission tax, an input tax and an abatement subsidy respectively. The social optimal emission flow is imposed into the private problem. To provide tractable analytical results, a Cobb-Douglas type production function is used to describe the joint production process of the desired output and undesired output (i.e., electricity and emissions). A modified Hamiltonian approach is employed to solve the system and the steady state solutions are examined for policy implications. The theoretical analysis suggests that the ratio of emissions to desired output (refer to 'emission factor'), is a function of productive capital and other parameters. The finding of non-constant emission factor shows that reducing emissions without further cutting back the production of desired outputs is feasible under some circumstances. Rather than an ad hoc specification, the optimal conditions derived from our theoretical framework are used to examine the relationship between desired output and emission level. Data comes from the China Statistical Yearbook and China Electric Power Yearbook and provincial information of electricity generation for the year of 1993-2003 are used to estimate the Cobb-Douglas type joint production by the full information maximum likelihood (FIML) method. The empirical analysis shed light on the optimal policies of emissions control required for achieving the social goal in a private context. The results suggest that the efficiency of abatement technology is crucial for the timing of executing the emission tax. And emission tax is preferred to an input tax, as long as the detection of emissions is not costly and abatement technology is efficient. Keywords: Economic growth, Carbon emission, Power generation, Joint production, China

Steelmaking process control using remote ultraviolet atomic emission spectroscopy

NASA Astrophysics Data System (ADS)

Arnold, Samuel

Steelmaking in North America is a multi-billion dollar industry that has faced tremendous economic and environmental pressure over the past few decades. Fierce competition has driven steel manufacturers to improve process efficiency through the development of real-time sensors to reduce operating costs. In particular, much attention has been focused on end point detection through furnace off gas analysis. Typically, off-gas analysis is done with extractive sampling and gas analyzers such as Non-dispersive Infrared Sensors (NDIR). Passive emission spectroscopy offers a more attractive approach to end point detection as the equipment can be setup remotely. Using high resolution UV spectroscopy and applying sophisticated emission line detection software, a correlation was observed between metal emissions and the process end point during field trials. This correlation indicates a relationship between the metal emissions and the status of a steelmaking melt which can be used to improve overall process efficiency.

Transport solutions for cleaner air.

PubMed

Kelly, Frank J; Zhu, Tong

2016-05-20

In cities across the globe, road transport remains an important source of air pollutants that are linked with acute and chronic health effects. Decreasing vehicle emissions--while maintaining or increasing commuter journeys--remains a major challenge for city administrators. In London, congestion-charging and a citywide low-emission zone failed to bring nitrogen dioxide concentrations under control. In Beijing, controls on the purchase and use of cars have not decreased transport emissions to a sufficient extent. As cities continue to grow, not even zero-emission vehicles are the solution. Moving increasingly large numbers of people efficiently around a city can only be achieved by expanding mass transit systems. Copyright © 2016, American Association for the Advancement of Science.

40 CFR Table 1 to Subpart Oooo of... - Emission Limits for New or Reconstructed and Existing Affected Sources in the Printing, Coating...

Code of Federal Regulations, 2010 CFR

2010-07-01

... may choose any one of the following limits:Reduce organic HAP emissions to the atmosphere by achieving... atmosphere to no more than 0.08 kg of organic HAP per kg of solids applied; or If you use an oxidizer to... emissions to the atmosphere by achieving at least a 97 percent organic HAP overall control efficiency; Limit...

40 CFR Table 1 to Subpart Oooo of... - Emission Limits for New or Reconstructed and Existing Affected Sources in the Printing, Coating...

Code of Federal Regulations, 2011 CFR

2011-07-01

... may choose any one of the following limits:Reduce organic HAP emissions to the atmosphere by achieving... atmosphere to no more than 0.08 kg of organic HAP per kg of solids applied; or If you use an oxidizer to... emissions to the atmosphere by achieving at least a 97 percent organic HAP overall control efficiency; Limit...

Isoprene emission protects photosynthesis but reduces plant productivity during drought in transgenic tobacco (Nicotiana tabacum) plants.

PubMed

Ryan, Annette C; Hewitt, C Nicholas; Possell, Malcolm; Vickers, Claudia E; Purnell, Anna; Mullineaux, Philip M; Davies, William J; Dodd, Ian C

2014-01-01

Isoprene protects the photosynthetic apparatus of isoprene-emitting plants from oxidative stress. The role of isoprene in the response of plants to drought is less clear. Water was withheld from transgenic isoprene-emitting and non-emitting tobacco (Nicotiana tabacum) plants, to examine: the response of isoprene emission to plant water deficit; a possible relationship between concentrations of the drought-induced phytohormone abscisic acid (ABA) and isoprene; and whether isoprene affected foliar reactive oxygen species (ROS) and lipid peroxidation levels. Isoprene emission did not affect whole-plant water use, foliar ABA concentration or leaf water potential under water deficit. Compared with well-watered controls, droughted non-emitting plants significantly increased ROS content (31-46%) and lipid peroxidation (30-47%), concomitant with decreased operating and maximum efficiencies of photosystem II photochemistry and lower leaf and whole-plant water use efficiency (WUE). Droughted isoprene-emitting plants showed no increase in ROS content or lipid peroxidation relative to well-watered controls, despite isoprene emission decreasing before leaf wilting. Although isoprene emission protected the photosynthetic apparatus and enhanced leaf and whole-plant WUE, non-emitting plants had 8-24% more biomass under drought, implying that isoprene emission incurred a yield penalty. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

Emissions from prescribed burning of timber slash piles in Oregon

NASA Astrophysics Data System (ADS)

Aurell, Johanna; Gullett, Brian K.; Tabor, Dennis; Yonker, Nick

2017-02-01

Emissions from burning piles of post-harvest timber slash (Douglas-fir) in Grande Ronde, Oregon were sampled using an instrument platform lofted into the plume using a tether-controlled aerostat or balloon. Emissions of carbon monoxide, carbon dioxide, methane, particulate matter (PM2.5), black carbon, ultraviolet absorbing PM, elemental/organic carbon, filter-based metals, polycyclic aromatic hydrocarbons (PAHs), polychlorinated dibenzodioxins/dibenzofurans (PCDD/PCDF), and volatile organic compounds (VOCs) were sampled to determine emission factors, the amount of pollutant formed per amount of biomass burned. The effect on emissions from covering the piles with polyethylene (PE) sheets to prevent fuel wetting versus uncovered piles was also determined. Results showed that the uncovered ("wet") piles burned with lower combustion efficiency and higher emission factors for VOCs, PM2.5, PCDD/PCDF, and PAHs. Removal of the PE prior to ignition, variation of PE size, and changing PE thickness resulted in no statistical distinction between emissions. Results suggest that dry piles, whether covered with PE or not, exhibited statistically significant lower emissions than wet piles due to better combustion efficiency.

40 CFR 63.2354 - What performance tests, design evaluations, and performance evaluations must I conduct?

Code of Federal Regulations, 2010 CFR

2010-07-01

..., appendix A, to determine compliance with the organic HAP or TOC emission limit, you may use EPA Method 18... formaldehyde control efficiency as a surrogate for total organic HAP or TOC efficiency, or at the outlet of a...

Evaluation of particulate matter emissions from manganese alloy production using life-cycle assessment.

PubMed

Davourie, Julia; Westfall, Luke; Ali, Mohammed; McGough, Doreen

2017-01-01

Life-cycle assessments (LCAs) provide a wealth of industry data to assist in evaluating the environmental impacts of industrial processes and product supply chains. In this investigation, data from a recent LCA covering global manganese alloy production was used to evaluate sources of particulate matter (PM) emissions associated with the manganese alloy supply chain. The analysis is aimed at providing an empirical, industry-averaged breakdown of the contribution that processes and emissions controls have on total emissions, manganese releases and occupational exposure. The assessment shows that 66% of PM emissions associated with manganese production occur beyond manganese facilities. Direct or on-site emissions represent 34% of total PM and occur predominantly as disperse sources during mineral extraction and hauling, and as primary furnace emissions. The largest contribution of manganese-bearing PM at ground-level is associated with fugitive emissions from metal and slag tapping, casting, crushing and screening. The evaluation provides a high-level ranking of emissions by process area, to assist in identifying priority areas for industry-wide initiatives to reduce emissions and occupational exposure of manganese. The range of PM emission levels in industry indicate that further enhancements in PM emissions can be achieved by sharing of best practices in emissions controls, limiting furnace conditions which lead to by-passing of emissions controls and application of secondary emission controls to capture fugitive emissions during tapping and casting. The LCA approach to evaluating PM emissions underscores the important role that process optimization and resource efficiency have on reducing PM emissions throughout the manganese supply chain. Copyright © 2016. Published by Elsevier B.V.

Regenerative braking system of PM synchronous motor

NASA Astrophysics Data System (ADS)

Gao, Qian; Lv, Chengxing; Zhao, Na; Zang, Hechao; Jiang, Huilue; Zhang, Zhaowen; Zhang, Fengli

2018-04-01

Permanent-magnet synchronous motor is widely adopted in many fields with the advantage of a high efficiency and a high torque density. Regenerative Braking Systems (RBS) provide an efficient method to assist PMSM system achieve better fuel economy and lowering exhaust emissions. This paper describes the design and testing of the regenerative braking systems of PMSM. The mode of PWM duty has been adjusted to control regenerative braking of PMSM using energy controller for the port-controlled Hamiltonian model. The simulation analysis indicates that a smooth control could be realized and the highest efficiency and the smallest current ripple could be achieved by Regenerative Braking Systems.

FY2015 Annual Report for Alternative Fuels DISI Engine Research.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sjöberg, Carl-Magnus G.

2016-01-01

Climate change and the need to secure energy supplies are two reasons for a growing interest in engine efficiency and alternative fuels. This project contributes to the science-base needed by industry to develop highly efficient DISI engines that also beneficially exploit the different properties of alternative fuels. Our emphasis is on lean operation, which can provide higher efficiencies than traditional non-dilute stoichiometric operation. Since lean operation can lead to issues with ignition stability, slow flame propagation and low combustion efficiency, we focus on techniques that can overcome these challenges. Specifically, fuel stratification is used to ensure ignition and completeness ofmore » combustion but has soot- and NOx- emissions challenges. For ultralean well-mixed operation, turbulent deflagration can be combined with controlled end-gas auto-ignition to render mixed-mode combustion that facilitates high combustion efficiency. However, the response of both combustion and exhaust emissions to these techniques depends on the fuel properties. Therefore, to achieve optimal fuel-economy gains, the engine combustion-control strategies must be adapted to the fuel being utilized.« less

Tuning Fluorescence Direction with Plasmonic Metal–Dielectric– Metal Substrates

PubMed Central

Choudhury, Sharmistha Dutta; Badugu, Ramachandram; Nowaczyk, Kazimierz; Ray, Krishanu; Lakowicz, Joseph R.

2013-01-01

Controlling the emission properties of fluorophores is essential for improving the performance of fluorescence-based techniques in modern biochemical research, medical diagnosis, and sensing. Fluorescence emission is isotropic in nature, which makes it difficult to capture more than a small fraction of the total emission. Metal– dielectric–metal (MDM) substrates, discussed in this Letter, convert isotropic fluorescence into beaming emission normal to the substrate. This improves fluorescence collection efficiency and also opens up new avenues for a wide range of fluorescence-based applications. We suggest that MDM substrates can be readily adapted for multiple uses, such as in microarray formats, for directional fluorescence studies of multiple probes or for molecule-specific sensing with a high degree of spatial control over the fluorescence emission. SECTION: Physical Processes in Nanomaterials and Nanostructures PMID:24013521

40 CFR 63.1426 - Process vent requirements for determining organic HAP concentration, control efficiency, and...

Code of Federal Regulations, 2011 CFR

2011-07-01

... National Emission Standards for Hazardous Air Pollutant Emissions for Polyether Polyols Production § 63... percent reduction may be measured as total epoxide, total organic HAP, or as TOC minus methane and ethane... TOC (minus methane and ethane) concentrations in all process vent streams and primary and secondary...

40 CFR 63.1426 - Process vent requirements for determining organic HAP concentration, control efficiency, and...

Code of Federal Regulations, 2012 CFR

2012-07-01

... National Emission Standards for Hazardous Air Pollutant Emissions for Polyether Polyols Production § 63... percent reduction may be measured as total epoxide, total organic HAP, or as TOC minus methane and ethane... TOC (minus methane and ethane) concentrations in all process vent streams and primary and secondary...

Optimization of Wastewater Lift Stations for Reduction of Energy Usage and Greenhouse Gas Emissions (WERF Report INFR3R11)

EPA Science Inventory

One of the major contributions of Greenhouse Gas (GHG) emissions from water resource recovery facilities results from the energy used by the pumping regime of the lift stations. This project demonstrated an energy-efficient control method of lift station system operation that uti...

40 CFR 63.420 - Applicability.

Code of Federal Regulations, 2012 CFR

2012-07-01

...-CE)+0.17 (TE)+0.08(TES)+0.038(TI)+8.5×10-6(C)+KQ]+0.04(OE) where: ET = emissions screening factor for... efficiency limitation on potential to emit for the vapor processing system used to control emissions from... of external floating roof gasoline storage vessels with only primary seals; TES = total number of...

40 CFR 63.420 - Applicability.

Code of Federal Regulations, 2011 CFR

2011-07-01

...-CE)+0.17 (TE)+0.08(TES)+0.038(TI)+8.5×10-6(C)+KQ]+0.04(OE) where: ET = emissions screening factor for... efficiency limitation on potential to emit for the vapor processing system used to control emissions from... of external floating roof gasoline storage vessels with only primary seals; TES = total number of...

40 CFR 63.420 - Applicability.

Code of Federal Regulations, 2010 CFR

2010-07-01

...-CE)+0.17 (TE)+0.08(TES)+0.038(TI)+8.5×10-6(C)+KQ]+0.04(OE) where: ET = emissions screening factor for... efficiency limitation on potential to emit for the vapor processing system used to control emissions from... of external floating roof gasoline storage vessels with only primary seals; TES = total number of...

40 CFR 63.420 - Applicability.

Code of Federal Regulations, 2013 CFR

2013-07-01

...-CE)+0.17 (TE)+0.08(TES)+0.038(TI)+8.5×10-6(C)+KQ]+0.04(OE) where: ET = emissions screening factor for... efficiency limitation on potential to emit for the vapor processing system used to control emissions from... of external floating roof gasoline storage vessels with only primary seals; TES = total number of...

40 CFR 63.420 - Applicability.

Code of Federal Regulations, 2014 CFR

2014-07-01

...)(1-CE)+0.17 (TE)+0.08(TES)+0.038(TI)+8.5×10-6(C)+KQ]+0.04(OE) where: ET = emissions screening factor... efficiency limitation on potential to emit for the vapor processing system used to control emissions from... of external floating roof gasoline storage vessels with only primary seals; TES = total number of...

Control of diesel soot and NOx emissions with a particulate trap and EGR.

PubMed

Liu, Rui-xiang; Gao, Xi-yan; Yang, De-sheng; Xu, Xiao-guang

2005-01-01

The exhaust gas recirculation (EGR), coupled with a high-collection efficiency particulate trap to simultaneously control smoke and NOx emissions from diesel engines were studied. This ceramic trap developed previously provided the soot cleaning efficiency of 99%, the regeneration efficiency reaches 80% and the ratio of success reaches 97%, which make EGR used in diesel possible. At the presence of EGR, opening of the regeneration control valve of the trap was over again optimized to compensate for the decrease of the oxygen concentration in the exhaust gas resulted from EGR. The results indicated the cleaning efficiency and regeneration performance of the trap were maintained at the same level except that the back pressure increased faster. A new EGR system was developed, which is based on a wide range oxygen (UEGO) sensor. Experiments were carried out under steady state conditions while maintaining the engine speed at 1600 r/min, setting the engine loads at 0%, 25%, 50%, 75% and 100% respectively. Throughout each test the EGR rate was kept at nine different settings and data were taken with the gas analyzer and UEGO sensor. Then, the EGR rate and engine load maps, which showed the tendencies of NOx, CO and HC emissions from diesel engine, were made using the measured data. Using the maps, the author set up the EGR regulation, the relationship between the optimal amounts of EGR flow and the equivalence ratio, sigma, where sigma = 14.5/AFR.

High-efficiency electroluminescence and amplified spontaneous emission from a thermally activated delayed fluorescent near-infrared emitter

NASA Astrophysics Data System (ADS)

Kim, Dae-Hyeon; D'Aléo, Anthony; Chen, Xian-Kai; Sandanayaka, Atula D. S.; Yao, Dandan; Zhao, Li; Komino, Takeshi; Zaborova, Elena; Canard, Gabriel; Tsuchiya, Youichi; Choi, Eunyoung; Wu, Jeong Weon; Fages, Frédéric; Brédas, Jean-Luc; Ribierre, Jean-Charles; Adachi, Chihaya

2018-02-01

Near-infrared organic light-emitting diodes and semiconductor lasers could benefit a variety of applications including night-vision displays, sensors and information-secured displays. Organic dyes can generate electroluminescence efficiently at visible wavelengths, but organic light-emitting diodes are still underperforming in the near-infrared region. Here, we report thermally activated delayed fluorescent organic light-emitting diodes that operate at near-infrared wavelengths with a maximum external quantum efficiency of nearly 10% using a boron difluoride curcuminoid derivative. As well as an effective upconversion from triplet to singlet excited states due to the non-adiabatic coupling effect, this donor-acceptor-donor compound also exhibits efficient amplified spontaneous emission. By controlling the polarity of the active medium, the maximum emission wavelength of the electroluminescence spectrum can be tuned from 700 to 780 nm. This study represents an important advance in near-infrared organic light-emitting diodes and the design of alternative molecular architectures for photonic applications based on thermally activated delayed fluorescence.

Solar energy conversion with photon-enhanced thermionic emission

NASA Astrophysics Data System (ADS)

Kribus, Abraham; Segev, Gideon

2016-07-01

Photon-enhanced thermionic emission (PETE) converts sunlight to electricity with the combined photonic and thermal excitation of charge carriers in a semiconductor, leading to electron emission over a vacuum gap. Theoretical analyses predict conversion efficiency that can match, or even exceed, the efficiency of traditional solar thermal and photovoltaic converters. Several materials have been examined as candidates for radiation absorbers and electron emitters, with no conclusion yet on the best set of materials to achieve high efficiency. Analyses have shown the complexity of the energy conversion and transport processes, and the significance of several loss mechanisms, requiring careful control of material properties and optimization of the device structure. Here we survey current research on PETE modeling, materials, and device configurations, outline the advances made, and stress the open issues and future research needed. Based on the substantial progress already made in this young topic, and the potential of high conversion efficiency based on theoretical performance limits, continued research in this direction is very promising and may yield a competitive technology for solar electricity generation.

Zinc oxide nanostructures and its nano-compounds for efficient visible light photo-catalytic processes

NASA Astrophysics Data System (ADS)

Adam, Rania E.; Alnoor, Hatim; Elhag, Sami; Nur, Omer; Willander, Magnus

2017-02-01

Zinc oxide (ZnO) in its nanostructure form is a promising material for visible light emission/absorption and utilization in different energy efficient photocatalytic processes. We will first present our recent results on the effect of varying the molar ratio of the synthesis nutrients on visible light emission. Further we will use the optimized conditions from the molar ration experiments to vary the synthesis processing parameters like stirring time etc. and the effect of all these parameters in order to optimize the efficiency and control the emission spectrum are investigated using different complementary techniques. Cathodoluminescence (CL) is combined with photoluminescence (PL) and electroluminescence (EL) as the techniques to investigate and optimizes visible light emission from ZnO/GaN light emitting diodes. We will then show and discuss our recent finding of the use of high quality ZnO nanoparticles (NPs) for efficient photo-degradation of toxic dyes using the visible spectra, namely with a wavelength up to 800 nm. In the end, we show how ZnO nanorods (NRs) are used as the first template to be transferred to bismuth zinc vanadate (BiZn2VO6). The BiZn2VO6 is then used to demonstrate efficient and cost effective hydrogen production through photoelectrochemical water splitting using solar radiation.

Study on Laws, Regulations and Standards on Energy Efficiency, Energy Conserving and Emission Reduction of Industrial Boilers in EU

NASA Astrophysics Data System (ADS)

Liu, Ren; Zhao, Yuejin; Chen, Haihong; Liang, Xiuying; Yang, Ming

2017-12-01

Industrial boilers are widely applied in such fields as factory power, building heating, and people’s lives; China is the world’s largest producer and user of industrial boilers, with very high annual energy consumption; clear requirements have been put forward by China on the energy efficiency since the “11th Five-year Plan” with the hope to save energy and reduce emission by means of energy efficiency standards and regulations on the supervision and control of various special equipment. So far, the energy efficiency of industrial boilers in China has been improved significantly but there is still a gap with the EU states. This paper analyzes the policies of energy efficiency, implementation models and methods of supervision and implementation at the EU level from laws, regulations, directives as well as standards; the paper also puts forward suggestions of energy conserving and emission reduction on the improvement of energy conserving capacity of industrial boilers in China through studying the legislations and measures of the developed countries in energy conserving of boilers.

Sustainable Transportation: Accelerating Widespread Adoption of Energy Efficient Vehicles & Fuels (Brochure)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

2014-12-01

While energy efficient transportation strategies have the potential to simultaneously slash oil consumption and reduce greenhouse gas (GHG) emissions, a truly sustainable solution will require more than just putting drivers behind the wheels of new fuel-efficient cars. As the only national laboratory dedicated 100% to renewable energy and energy efficiency, the National Renewable Energy Laboratory (NREL) accelerates widespread adoption of high-performance, low-emission, energy-efficient passenger and freight vehicles, as well as alternative fuels and related infrastructure. Researchers collaborate closely with industry, government, and research partners, using a whole-systems approach to design better batteries, drivetrains, and engines, as well as thermal management,more » energy storage, power electronic, climate control, alternative fuel, combustion, and emission systems. NREL's sustainable transportation research, development, and deployment (RD&D) efforts are not limited to vehicles, roads, and fueling stations. The lab also explores ways to save energy and reduce GHGs by integrating transportation technology advancements with renewable energy generation, power grids and building systems, urban planning and policy, and fleet operations.« less

Evaluating the effects of China's pollution controls on inter-annual trends and uncertainties of atmospheric mercury emissions

NASA Astrophysics Data System (ADS)

Zhao, Y.; Zhong, H.; Zhang, J.; Nielsen, C. P.

2015-04-01

China's anthropogenic emissions of atmospheric mercury (Hg) are effectively constrained by national air pollution control and energy efficiency policies. In this study, improved methods, based on available data from domestic field measurements, are developed to quantify the benefits of Hg abatement by various emission control measures. Those measures include increased use of (1) flue gas desulfurization (FGD) and selective catalyst reduction (SCR) systems in power generation; (2) precalciner kilns with fabric filters (FF) in cement production; (3) mechanized coking ovens with electrostatic precipitators (ESP) in iron and steel production; and (4) advanced production technologies in nonferrous metal smelting. Investigation reveals declining trends in emission factors for each of these sources, which together drive a much slower growth of total Hg emissions than the growth of China's energy consumption and economy, from 679 metric tons (t) in 2005 to 750 t in 2012. In particular, estimated emissions from the above-mentioned four source types declined 3% from 2005 to 2012, which can be attributed to expanded deployment of technologies with higher energy efficiencies and air pollutant removal rates. Emissions from other anthropogenic sources are estimated to increase by 22% during the period. The species shares of total Hg emissions have been stable in recent years, with mass fractions of around 55, 39, and 6% for gaseous elemental Hg (Hg0), reactive gaseous mercury (Hg2+), and particle-bound mercury (Hgp), respectively. The higher estimate of total Hg emissions than previous inventories is supported by limited simulation of atmospheric chemistry and transport. With improved implementation of emission controls and energy saving, a 23% reduction in annual Hg emissions from 2012 to 2030, to below 600 t, is expected at the most. While growth in Hg emissions has been gradually constrained, uncertainties quantified by Monte Carlo simulation for recent years have increased, particularly for the power sector and particular industrial sources. The uncertainty (expressed as 95% confidence intervals) of Hg emissions from coal-fired power plants, for example, increased from -48-+73% in 2005 to -50-+89% in 2012. This is attributed mainly to increased penetration of advanced manufacturing and pollutant control technologies; the unclear operational status and relatively small sample sizes of field measurements of those processes have resulted in lower but highly varied emission factors. To reduce uncertainty and further confirm the benefits of pollution control and energy polices, therefore, systematic investigation of specific Hg pollution sources is recommended. The variability of temporal trends and spatial distributions of Hg emissions needs to be better tracked during the ongoing dramatic changes in China's economy, energy use, and air pollution status.

Resource Efficiency in the US Army Corps of Engineers: Examination of Strategies to Reduce Energy Use and Greenhouse Gas Emissions

DTIC Science & Technology

2012-09-15

Control 19 4,321 639 Office 10 4,387 584 Hydropower 5 2,885 504 2.1.2 NTV emissions NTV petroleum consumption information is a combination of ...reductions that will occur because of planned engine efficiency changes in the floating plant . These reductions total 8,956 MTCO2e. In addition, a ...and/or the implementation of a variety of measures such as passive solar energy, planting trees and plants around buildings to achieve desired

Efficiency of Emission Control Measures on Particulate Matter-Related Health Impacts and Economic Cost during the 2014 Asia-Pacific Economic Cooperation Meeting in Beijing.

PubMed

Liu, Qichen; Huang, Jing; Guo, Bin; Guo, Xinbiao

2016-12-28

Background : The Asia-Pacific Economic Cooperation (APEC) meeting was held from 5 November to 11 November 2014 in Beijing, and comprehensive emission control measures were implemented. The efficiency of these measures on particulate matter-related health impacts and economic cost need to be evaluated. Methods : The influences of emission control measures during APEC on particulate matter were evaluated, and health economic effects were assessed. Results : Average concentrations of PM 2.5 and PM 10 during APEC were reduced by 57.0%, and 50.6% respectively, compared with pre-APEC period. However, the concentrations of particulate matter rebounded after APEC. Compared with the pre-APEC and post-APEC periods, the estimated number of deaths caused by non-accidental, cardiovascular and respiratory diseases that could be attributed to PM 2.5 and PM 10 during the APEC were the lowest. The economic cost associated with mortality caused by PM 2.5 and PM 10 during the APEC were reduced by (61.3% and 66.6%) and (50.3% and 60.8%) respectively, compared with pre-APEC and post-APEC. Conclusions : The emission control measures were effective in improving short term air quality and reducing health risks and medical expenses during 2014 APEC, but more efforts is needed for long term and continuous air quality improvement and health protection.

Efficiency of Emission Control Measures on Particulate Matter-Related Health Impacts and Economic Cost during the 2014 Asia-Pacific Economic Cooperation Meeting in Beijing

PubMed Central

Liu, Qichen; Huang, Jing; Guo, Bin; Guo, Xinbiao

2016-01-01

Background: The Asia-Pacific Economic Cooperation (APEC) meeting was held from 5 November to 11 November 2014 in Beijing, and comprehensive emission control measures were implemented. The efficiency of these measures on particulate matter-related health impacts and economic cost need to be evaluated. Methods: The influences of emission control measures during APEC on particulate matter were evaluated, and health economic effects were assessed. Results: Average concentrations of PM2.5 and PM10 during APEC were reduced by 57.0%, and 50.6% respectively, compared with pre-APEC period. However, the concentrations of particulate matter rebounded after APEC. Compared with the pre-APEC and post-APEC periods, the estimated number of deaths caused by non-accidental, cardiovascular and respiratory diseases that could be attributed to PM2.5 and PM10 during the APEC were the lowest. The economic cost associated with mortality caused by PM2.5 and PM10 during the APEC were reduced by (61.3% and 66.6%) and (50.3% and 60.8%) respectively, compared with pre-APEC and post-APEC. Conclusions: The emission control measures were effective in improving short term air quality and reducing health risks and medical expenses during 2014 APEC, but more efforts is needed for long term and continuous air quality improvement and health protection. PMID:28036006

40 CFR Table 1 to Subpart Oooo of... - Emission Limits for New or Reconstructed and Existing Affected Sources in the Printing, Coating...

Code of Federal Regulations, 2012 CFR

2012-07-01

... operations You may choose any one of the following limits:Reduce organic HAP emissions to the atmosphere by... atmosphere to no more than 0.08 kg of organic HAP per kg of solids applied; or If you use an oxidizer to... emissions to the atmosphere by achieving at least a 97 percent organic HAP overall control efficiency; Limit...

40 CFR Table 1 to Subpart Oooo of... - Emission Limits for New or Reconstructed and Existing Affected Sources in the Printing, Coating...

Code of Federal Regulations, 2013 CFR

2013-07-01

... operations You may choose any one of the following limits:Reduce organic HAP emissions to the atmosphere by... atmosphere to no more than 0.08 kg of organic HAP per kg of solids applied; or If you use an oxidizer to... emissions to the atmosphere by achieving at least a 97 percent organic HAP overall control efficiency; Limit...

40 CFR Table 1 to Subpart Oooo of... - Emission Limits for New or Reconstructed and Existing Affected Sources in the Printing, Coating...

Code of Federal Regulations, 2014 CFR

2014-07-01

... operations You may choose any one of the following limits:Reduce organic HAP emissions to the atmosphere by... atmosphere to no more than 0.08 kg of organic HAP per kg of solids applied; or If you use an oxidizer to... emissions to the atmosphere by achieving at least a 97 percent organic HAP overall control efficiency; Limit...

Factors Affecting Aerosol Radiative Forcing

NASA Astrophysics Data System (ADS)

Wang, Jingxu; Lin, Jintai; Ni, Ruijing

2016-04-01

Rapid industrial and economic growth has meant a large amount of aerosols in the atmosphere with strong radiative forcing (RF) upon the climate system. Over parts of the globe, the negative forcing of aerosols has overcompensated for the positive forcing of greenhouse gases. Aerosol RF is determined by emissions and various chemical-transport-radiative processes in the atmosphere, a multi-factor problem whose individual contributors have not been well quantified. In this study, we analyze the major factors affecting RF of secondary inorganic aerosols (SIOAs, including sulfate, nitrate and ammonium), primary organic aerosol (POA), and black carbon (BC). We analyze the RF of aerosols produced by 11 major regions across the globe, including but not limited to East Asia, Southeast Asia, South Asia, North America, and Western Europe. Factors analyzed include population size, per capita gross domestic production (GDP), emission intensity (i.e., emissions per unit GDP), chemical efficiency (i.e., mass per unit emissions) and radiative efficiency (i.e., RF per unit mass). We find that among the 11 regions, East Asia produces the largest emissions and aerosol RF, due to relatively high emission intensity and a tremendous population size. South Asia produce the second largest RF of SIOA and BC and the highest RF of POA, in part due to its highest chemical efficiency among all regions. Although Southeast Asia also has large emissions, its aerosol RF is alleviated by its lowest chemical efficiency. The chemical efficiency and radiative efficiency of BC produced by the Middle East-North Africa are the highest across the regions, whereas its RF is lowered by a small per capita GDP. Both North America and Western Europe have low emission intensity, compensating for the effects on RF of large population sizes and per capita GDP. There has been a momentum to transfer industries to Southeast Asia and South Asia, and such transition is expected to continue in the coming years. The resulting relocation of emissions would meant drastic changes in both the spatial distribution and the magnitude of RF, with consequences on regional and global climate forcing. Our findings are relevant to global aerosol control and climate mitigation.

Application of microwave energy in the control of DPM, oxides of nitrogen and VOC emissions

NASA Astrophysics Data System (ADS)

Pallavkar, Sameer M.

The emissions of DPM (diesel particulate matter), NOx (oxides of nitrogen), and toxic VOCs (volatile organic compounds) from diesel engine exhaust gases and other sources such as chemical process industry and manufacturing industry have been a great environmental and health concern. Most control technologies for these emissions require elevated temperatures. The use of microwave energy as a source of heat energy, however, has not been fully explored. In this study, the microwave energy was used as the energy source in three separate emission control processes, namely, the regeneration of diesel particulate filter (DPF) for DPM control, the NOx reduction using a platinum catalyst, and the VOC destruction involving a ceramic based material. The study has demonstrated that microwave heating is an effective method in providing heat for the studied processes. The control efficiencies associated with the microwave-assisted processes have been observed to be high and acceptable. Further research, however, is required for the commercial use of these technologies.

Performance of a Retrofitted Multicyclone for PM2.5 Emission Control

NASA Astrophysics Data System (ADS)

Dewika, M.; Rashid, M.; Ammar, M. R.

2018-03-01

This paper presents on the performance of a retrofitted multicyclone system, which aims to increase the collection efficiency of PM2.5 (i.e. particulate size fraction ≤ 2.5 μm) emission. The multicyclone was retrofitted by extracting 15% and 20% of the total volumetric air flow rate at the dust hopper of the unit using an additional Induced Draft Fan. The total collection efficiency with and without the extraction was measured at various air volumetric flow rates and particulate mass inlet concentration. The results showed that there was a reduction of 12% to 54% depending on the inlet concentration of PM2.5 emission in the stack with compared to without extraction increasing the collection efficiency of the retrofitted multicyclone. The finding suggests that a simple technique of applying gas extraction at the dust hopper of a multicyclone as reported in this study able to increase the overall performance in fine particulate collection.

Spatially Refined Aerosol Direct Radiative Forcing Efficiencies

NASA Technical Reports Server (NTRS)

Henze, Daven K.; Shindell, Drew Todd; Akhtar, Farhan; Spurr, Robert J. D.; Pinder, Robert W.; Loughlin, Dan; Kopacz, Monika; Singh, Kumaresh; Shim, Changsub

2012-01-01

Global aerosol direct radiative forcing (DRF) is an important metric for assessing potential climate impacts of future emissions changes. However, the radiative consequences of emissions perturbations are not readily quantified nor well understood at the level of detail necessary to assess realistic policy options. To address this challenge, here we show how adjoint model sensitivities can be used to provide highly spatially resolved estimates of the DRF from emissions of black carbon (BC), primary organic carbon (OC), sulfur dioxide (SO2), and ammonia (NH3), using the example of emissions from each sector and country following multiple Representative Concentration Pathway (RCPs). The radiative forcing efficiencies of many individual emissions are found to differ considerably from regional or sectoral averages for NH3, SO2 from the power sector, and BC from domestic, industrial, transportation and biomass burning sources. Consequently, the amount of emissions controls required to attain a specific DRF varies at intracontinental scales by up to a factor of 4. These results thus demonstrate both a need and means for incorporating spatially refined aerosol DRF into analysis of future emissions scenario and design of air quality and climate change mitigation policies.

Marginal abatement cost curves for NOx incorporating both controls and alternative measures

EPA Science Inventory

A marginal abatement cost curve (MACC) traces out the efficient marginal abatement cost level for any aggregate emissions target when a least cost approach is implemented. In order for it to represent the efficient MAC level, all abatement opportunities across all sectors and loc...

Tailored Emission Properties of ZnTe/ZnTe:O/ZnO Core-Shell Nanowires Coupled with an Al Plasmonic Bowtie Antenna Array.

PubMed

Nie, Kui-Ying; Tu, Xuecou; Li, Jing; Chen, Xuanhu; Ren, Fang-Fang; Zhang, Guo-Gang; Kang, Lin; Gu, Shulin; Zhang, Rong; Wu, Peiheng; Zheng, Youdou; Tan, Hark Hoe; Jagadish, Chennupati; Ye, Jiandong

2018-06-14

The ability to manipulate light-matter interaction in semiconducting nanostructures is fascinating for implementing functionalities in advanced optoelectronic devices. Here, we report the tailoring of radiative emissions in a ZnTe/ZnTe:O/ZnO core-shell single nanowire coupled with a one-dimensional aluminum bowtie antenna array. The plasmonic antenna enables changes in the excitation and emission processes, leading to an obvious enhancement of near band edge emission (2.2 eV) and subgap excitonic emission (1.7 eV) bound to intermediate band states in a ZnTe/ZnTe:O/ZnO core-shell nanowire as well as surface-enhanced Raman scattering at room temperature. The increase of emission decay rate in the nanowire/antenna system, probed by time-resolved photoluminescence spectroscopy, yields an observable enhancement of quantum efficiency induced by local surface plasmon resonance. Electromagnetic simulations agree well with the experimental observations, revealing a combined effect of enhanced electric near-field intensity and the improvement of quantum efficiency in the ZnTe/ZnTe:O/ZnO nanowire/antenna system. The capability of tailoring light-matter interaction in low-efficient emitters may provide an alternative platform for designing advanced optoelectronic and sensing devices with precisely controlled response.

40 CFR 63.3981 - What definitions apply to this subpart?

Code of Federal Regulations, 2011 CFR

2011-07-01

..., activators, accelerators). Add-on control means an air pollution control device, such as a thermal oxidizer or carbon adsorber, that reduces pollution in an air stream by destruction or removal before... directing those emissions into an add-on air pollution control device. Capture efficiency or capture system...

Future trends of global atmospheric antimony emissions from anthropogenic activities until 2050

NASA Astrophysics Data System (ADS)

Zhou, Junrui; Tian, Hezhong; Zhu, Chuanyong; Hao, Jiming; Gao, Jiajia; Wang, Yong; Xue, Yifeng; Hua, Shenbin; Wang, Kun

2015-11-01

This paper presents the scenario forecast of global atmospheric antimony (Sb) emissions from anthropogenic activities till 2050. The projection scenarios are built based on the comprehensive global antimony emission inventory for the period 1995-2010 which is reported in our previous study. Three scenarios are set up to investigate the future changes of global antimony emissions as well as their source and region contribution characteristics. Trends of activity levels specified as 5 primary source categories are projected by combining the historical trend extrapolation with EIA International energy outlook 2013, while the source-specific dynamic emission factors are determined by applying transformed normal distribution functions. If no major changes in the efficiency of emission control are introduced and keep current air quality legislations (Current Legislation scenario), global antimony emissions will increase by a factor of 2 between 2010 and 2050. The largest increase in Sb emissions is projected from Asia due to large volume of nonferrous metals production and waste incineration. In case of enforcing the pollutant emission standards (Strengthened Control scenario), global antimony emissions in 2050 will stabilize with that of 2010. Moreover, we can anticipate further declines in Sb emissions for all continents with the best emission control performances (Maximum Feasible Technological Reduction scenario). Future antimony emissions from the top 10 largest emitting countries have also been calculated and source category contributions of increasing emissions of these countries present significant diversity. Furthermore, global emission projections in 2050 are distributed within a 1° × 1°latitude/longitude grid. East Asia, Western Europe and North America present remarkable differences in emission intensity under the three scenarios, which implies that source-and-country specific control measures are necessary to be implemented for abating Sb emissions from varied continents and countries in the future.

An analytical investigation of NO sub x control techniques for methanol fueled spark ignition engines

NASA Technical Reports Server (NTRS)

Browning, L. H.; Argenbright, L. A.

1983-01-01

A thermokinetic SI engine simulation was used to study the effects of simple nitrogen oxide control techniques on performance and emissions of a methanol fueled engine. As part of this simulation, a ring crevice storage model was formulated to predict UBF emissions. The study included spark retard, two methods of compression ratio increase and EGR. The study concludes that use of EGR in high turbulence, high compression engines will both maximize power and thermal efficiency while minimizing harmful exhaust pollutants.

Radiative forcing associated with particulate carbon emissions resulting from the use of mercury control technology.

PubMed

Lin, Guangxing; Penner, Joyce E; Clack, Herek L

2014-09-02

Injection of powdered activated carbon (PAC) adsorbents into the flue gas of coal fired power plants with electrostatic precipitators (ESPs) is the most mature technology to control mercury emissions for coal combustion. However, the PAC itself can penetrate ESPs to emit into the atmosphere. These emitted PACs have similar size and optical properties to submicron black carbon (BC) and thus could increase BC radiative forcing unintentionally. The present paper estimates, for the first time, the potential emission of PAC together with their climate forcing. The global average maximum potential emissions of PAC is 98.4 Gg/yr for the year 2030, arising from the assumed adoption of the maximum potential PAC injection technology, the minimum collection efficiency, and the maximum PAC injection rate. These emissions cause a global warming of 2.10 mW m(-2) at the top of atmosphere and a cooling of -2.96 mW m(-2) at the surface. This warming represents about 2% of the warming that is caused by BC from direct fossil fuel burning and 0.86% of the warming associated with CO2 emissions from coal burning in power plants. Its warming is 8 times more efficient than the emitted CO2 as measured by the 20-year-integrated radiative forcing per unit of carbon input (the 20-year Global Warming Potential).

Ammonia Generation and Utilization in a Passive SCR (TWC+SCR) System on Lean Gasoline Engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prikhodko, Vitaly Y.; James E. Parks, II; Pihl, Josh A.

Lean gasoline engines offer greater fuel economy than the common stoichiometric gasoline engine, but the current three way catalyst (TWC) on stoichiometric engines is unable to control nitrogen oxide (NOX) emissions in oxidizing exhaust. For these lean gasoline engines, lean NOX emission control is required to meet existing Tier 2 and upcoming Tier 3 emission regulations set by the U.S. Environmental Protection Agency (EPA). While urea-based selective catalytic reduction (SCR) has proven effective in controlling NOX from diesel engines, the urea storage and delivery components can add significant size and cost. As such, onboard NH 3 production via a passivemore » SCR approach is of interest. In a passive SCR system, NH 3 is generated over a close-coupled TWC during periodic slightly rich engine operation and subsequently stored on an underfloor SCR catalyst. Upon switching to lean operation, NOX passes through the TWC and is reduced by the stored NH 3 on the SCR catalyst. In this work, a passive SCR system was evaluated on a 2.0-liter BMW lean burn gasoline direct injection engine to assess NH 3 generation over a Pd-only TWC and utilization over a Cu-based SCR catalyst. System NOX reduction efficiency and fuel efficiency improvement compared to stoichiometric engine operation were measured. A feedback control strategy based on cumulative NH 3 produced by the TWC during rich operation and NOX emissions during lean operation was implemented on the engine to control lean/rich cycle timing. At an SCR average inlet temperature of 350 °C, an NH 3:NOX ratio of 1.15:1 (achieved through longer rich cycle timing) resulted in 99.7 % NOX conversion. Increasing NH 3 generation further resulted in even higher NOX conversion; however, tailpipe NH 3 emissions resulted. At higher underfloor temperatures, NH 3 oxidation over the SCR limited NH 3 availability for NOX reduction. At the engine conditions studied, greater than 99 % NOX conversion was achieved with passive SCR while delivering fuel efficiency benefits ranging between 6-11 % compared with stoichiometric operation.« less

Ammonia Generation and Utilization in a Passive SCR (TWC+SCR) System on Lean Gasoline Engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prikhodko, Vitaly Y; Parks, II, James E; Pihl, Josh A

Lean gasoline engines offer greater fuel economy than the common stoichiometric gasoline engine, but the current three-way catalyst (TWC) on stoichiometric engines is unable to control nitrogen oxide (NOX) emissions in the oxygen-rich exhaust. Thus, lean NOX emission control is required to meet existing Tier 2 and upcoming Tier 3 emission regulations set by the U.S. Environmental Protection Agency (EPA). While urea-based selective catalytic reduction (SCR) has proven effective in controlling NOX from diesel engines, the urea storage and delivery components can add significant size and cost. As such, onboard NH3 production via a passive SCR approach is of interest.more » In a passive SCR system, NH3 is generated over a close-coupled TWC during periodic slightly rich engine operation and subsequently stored on an underfloor SCR catalyst. Upon switching to lean operation, NOX passes through the TWC and is reduced by the stored NH3 on the SCR catalyst. In this work, a passive SCR system was evaluated on a 2.0-liter BMW lean burn gasoline direct injection engine to assess NH3 generation over a Pd-only TWC and utilization over a Cu-based SCR catalyst. System NOX reduction efficiency and fuel efficiency improvement compared to stoichiometric engine operation were measured. A feedback control strategy based on cumulative NH3 produced by the TWC during rich operation and NOX emissions during lean operation was implemented on the engine to control lean/rich cycle timing. 15% excess NH3 production over a 1:1 NH3:NOX ratio was required (via longer rich cycle timing) to achieve 99.7% NOX conversion at an SCR average inlet temperature of 350 C. Increasing NH3 generation further resulted in even higher NOX conversion; however, tailpipe NH3 emissions resulted. At higher temperatures, NH3 oxidation becomes important and limits NH3 availability for NOX reduction. At the engine conditions studied here, greater than 99% NOX conversion was achieved with passive SCR while delivering fuel efficiency benefits ranging between 6-11% compared with stoichiometric operation.« less

Ammonia Generation and Utilization in a Passive SCR (TWC+SCR) System on Lean Gasoline Engine

DOE PAGES

Prikhodko, Vitaly Y.; James E. Parks, II; Pihl, Josh A.; ...

2016-04-05

Lean gasoline engines offer greater fuel economy than the common stoichiometric gasoline engine, but the current three way catalyst (TWC) on stoichiometric engines is unable to control nitrogen oxide (NOX) emissions in oxidizing exhaust. For these lean gasoline engines, lean NOX emission control is required to meet existing Tier 2 and upcoming Tier 3 emission regulations set by the U.S. Environmental Protection Agency (EPA). While urea-based selective catalytic reduction (SCR) has proven effective in controlling NOX from diesel engines, the urea storage and delivery components can add significant size and cost. As such, onboard NH 3 production via a passivemore » SCR approach is of interest. In a passive SCR system, NH 3 is generated over a close-coupled TWC during periodic slightly rich engine operation and subsequently stored on an underfloor SCR catalyst. Upon switching to lean operation, NOX passes through the TWC and is reduced by the stored NH 3 on the SCR catalyst. In this work, a passive SCR system was evaluated on a 2.0-liter BMW lean burn gasoline direct injection engine to assess NH 3 generation over a Pd-only TWC and utilization over a Cu-based SCR catalyst. System NOX reduction efficiency and fuel efficiency improvement compared to stoichiometric engine operation were measured. A feedback control strategy based on cumulative NH 3 produced by the TWC during rich operation and NOX emissions during lean operation was implemented on the engine to control lean/rich cycle timing. At an SCR average inlet temperature of 350 °C, an NH 3:NOX ratio of 1.15:1 (achieved through longer rich cycle timing) resulted in 99.7 % NOX conversion. Increasing NH 3 generation further resulted in even higher NOX conversion; however, tailpipe NH 3 emissions resulted. At higher underfloor temperatures, NH 3 oxidation over the SCR limited NH 3 availability for NOX reduction. At the engine conditions studied, greater than 99 % NOX conversion was achieved with passive SCR while delivering fuel efficiency benefits ranging between 6-11 % compared with stoichiometric operation.« less

Current and future emissions of primary pollutants from coal-fired power plants in Shaanxi, China.

PubMed

Xu, Yong; Hu, Jianlin; Ying, Qi; Hao, Hongke; Wang, Dexiang; Zhang, Hongliang

2017-10-01

A high-resolution inventory of primary atmospheric pollutants from coal-fired power plants in Shaanxi in 2012 was built based on a detailed database compiled at unit level involving unit capacity, boiler size and type, commission time, corresponding control technologies, and average coal quality of 72 power plants. The pollutants included SO 2 , NO x , fine particulate matter (PM 2.5 ), inhalable particulate matter (PM 10 ), organic carbon (OC), elemental carbon (EC), carbon monoxide (CO) and non-methane volatile organic compounds (NMVOC). Emission factors for SO 2 , NO x , PM 2.5 and PM 10 were adopted from standardized official promulgation, supplemented by those from local studies. The estimated annual emissions of SO 2 , NO x , PM 2.5 , PM 10 , EC, OC, CO and NMVOC were 152.4, 314.8, 16.6, 26.4, 0.07, 0.27, 64.9 and 2.5kt, respectively. Small units (<100MW), which accounted for ~60% of total unit numbers, had less coal consumption but higher emission rates compared to medium (≥100MW and <300MW) and large units (≥300MW). Main factors affecting SO 2 , NO x , PM 2.5 and PM 10 emissions were decontamination efficiency, sulfur content and ash content of coal. Weinan and Xianyang were the two cities with the highest emissions, and Guanzhong Plain had the largest emission density. Despite the projected growth of coal consumption, emissions would decrease in 2030 due to improvement in emission control technologies and combustion efficiencies. SO 2 and NO x emissions would experience significant reduction by ~81% and ~84%, respectively. PM 2.5 , PM 10 , EC and OC would be decreased by ~43% and CO and NMVOC would be reduced by ~16%. Copyright © 2017 Elsevier B.V. All rights reserved.

Internal combustion engine controls for reduced exhausts contaminants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matthews, D.R. Jr.

1974-06-04

An electrochemical control system for achieving optimum efficiency in the catalytic conversion of hydrocarbon and carbon monoxide emissions from internal combustion engines is described. The system automatically maintains catalyst temperature at a point for maximum pollutant conversion by adjusting ignition timing and fuel/air ratio during warm-up and subsequent operation. Ignition timing is retarded during engine warm-up to bring the catalytic converter to an efficient operating temperature within a minimum period of time. After the converter reaches a predetermined minimum temperature, the spark is advanced to within its normal operating range. A needle-valve adjustment during warm-up is employed to enrich themore » fuel/air mixture by approximately 10 percent. Following warm-up and attainment of a predetermined catalyst temperature, the needle valve is moved automatically to its normal position (e.g., a fuel/air ratio of 16:1). Although the normal lean mixture causes increased amounts of nitrogen oxide emissions, present NO/sub x/ converters appear capable of handling the increased emissions under normal operating conditions.« less

Nitrapyrin addition mitigates nitrous oxide emissions and raises nitrogen use efficiency in plastic-film-mulched drip-fertigated cotton field.

PubMed

Liu, Tao; Liang, Yongchao; Chu, Guixin

2017-01-01

Nitrification inhibitors (NIs) have been used extensively to reduce nitrogen losses and increase crop nitrogen nutrition. However, information is still scant regarding the influence of NIs on nitrogen transformation, nitrous oxide (N2O) emission and nitrogen utilization in plastic-film-mulched calcareous soil under high frequency drip-fertigated condition. Therefore, a field trial was conducted to evaluate the effect of nitrapyrin (2-chloro-6-(trichloromethyl)-pyridine) on soil mineral nitrogen (N) transformation, N2O emission and nitrogen use efficiency (NUE) in a drip-fertigated cotton-growing calcareous field. Three treatments were established: control (no N fertilizer), urea (225 kg N ha-1) and urea+nitrapyrin (225 kg N ha-1+2.25 kg nitrapyrin ha-1). Compared with urea alone, urea plus nitrapyrin decreased the average N2O emission fluxes by 6.6-21.8% in June, July and August significantly in a drip-fertigation cycle. Urea application increased the seasonal cumulative N2O emission by 2.4 kg N ha-1 compared with control, and nitrapyrin addition significantly mitigated the seasonal N2O emission by 14.3% compared with urea only. During the main growing season, the average soil ammonium nitrogen (NH4+-N) concentration was 28.0% greater and soil nitrate nitrogen (NO3--N) concentration was 13.8% less in the urea+nitrapyrin treatment than in the urea treatment. Soil NO3--N and water-filled pore space (WFPS) were more closely correlated than soil NH4+-N with soil N2O fluxes under drip-fertigated condition (P<0.001). Compared with urea alone, urea plus nitrapyrin reduced the seasonal N2O emission factor (EF) by 32.4% while increasing nitrogen use efficiency by 10.7%. The results demonstrated that nitrapyrin addition significantly inhibited soil nitrification and maintained more NH4+-N in soil, mitigated N2O losses and improved nitrogen use efficiency in plastic-film-mulched calcareous soil under high frequency drip-fertigated condition.

Nitrapyrin addition mitigates nitrous oxide emissions and raises nitrogen use efficiency in plastic-film-mulched drip-fertigated cotton field

PubMed Central

Liu, Tao; Chu, Guixin

2017-01-01

Nitrification inhibitors (NIs) have been used extensively to reduce nitrogen losses and increase crop nitrogen nutrition. However, information is still scant regarding the influence of NIs on nitrogen transformation, nitrous oxide (N2O) emission and nitrogen utilization in plastic-film-mulched calcareous soil under high frequency drip-fertigated condition. Therefore, a field trial was conducted to evaluate the effect of nitrapyrin (2-chloro-6-(trichloromethyl)-pyridine) on soil mineral nitrogen (N) transformation, N2O emission and nitrogen use efficiency (NUE) in a drip-fertigated cotton-growing calcareous field. Three treatments were established: control (no N fertilizer), urea (225 kg N ha-1) and urea+nitrapyrin (225 kg N ha-1+2.25 kg nitrapyrin ha-1). Compared with urea alone, urea plus nitrapyrin decreased the average N2O emission fluxes by 6.6–21.8% in June, July and August significantly in a drip-fertigation cycle. Urea application increased the seasonal cumulative N2O emission by 2.4 kg N ha-1 compared with control, and nitrapyrin addition significantly mitigated the seasonal N2O emission by 14.3% compared with urea only. During the main growing season, the average soil ammonium nitrogen (NH4+-N) concentration was 28.0% greater and soil nitrate nitrogen (NO3--N) concentration was 13.8% less in the urea+nitrapyrin treatment than in the urea treatment. Soil NO3--N and water-filled pore space (WFPS) were more closely correlated than soil NH4+-N with soil N2O fluxes under drip-fertigated condition (P<0.001). Compared with urea alone, urea plus nitrapyrin reduced the seasonal N2O emission factor (EF) by 32.4% while increasing nitrogen use efficiency by 10.7%. The results demonstrated that nitrapyrin addition significantly inhibited soil nitrification and maintained more NH4+-N in soil, mitigated N2O losses and improved nitrogen use efficiency in plastic-film-mulched calcareous soil under high frequency drip-fertigated condition. PMID:28481923

Coherent and noncoherent low-power diodes in clinical practice

NASA Astrophysics Data System (ADS)

Antipa, Ciprian; Pascu, Mihail-Lucian; Stanciulescu, Viorica; Vlaiculescu, Mihaela; Ionescu, Elena; Bordea, Daniel

1997-05-01

Clinical efficacy of the low power laser (LPL) in medical treatments is still not well established. In a double blind, placebo controlled study, we tried to find out first which type of LPL is more efficient, and second if coherence is an important character for clinical efficacy. We treated 1228 patients having different rheumatic diseases, with low power diode, used as follows: A group: IR coherent diode, continuous emission, 3 mW power; B group: IR coherent diode, pulsed emission, output power about 3 mW; C group: IR noncoherent diode continuous emission 9 mW power; D group: both IR diode lasers (continuous or pulsed) and HeNe laser, continuous emission, 2 mW power; E group: placebo laser as control group. The energy dose used for every group was the same, as well as the clinical protocols. The positive results were: 66.16% for A group; 64.06% for B group; 48.87% for C group; 76.66% for D group, and 39.07% for E group. Finally, we showed that LPL is really efficient in the treatment of some rheumatic diseases, especially when red and IR diode laser were used in combination. The type of emission (continuous or pulsed) is not important, but coherence is obviously necessary for clinical efficacy.

Effectiveness of transportation control measures : overview of the state of the practice.

DOT National Transportation Integrated Search

1996-01-01

Transportation control measures, or TCMs, are transportation measures or strategies intended both to reduce vehicle miles of travel (VMT) and to make those traveled more efficient. Although the term TCM has its origins in air quality and emissions re...

Water loss control using pressure management: life-cycle energy and air emission effects.

PubMed

Stokes, Jennifer R; Horvath, Arpad; Sturm, Reinhard

2013-10-01

Pressure management is one cost-effective and efficient strategy for controlling water distribution losses. This paper evaluates the life-cycle energy use and emissions for pressure management zones in Philadelphia, Pennsylvania, and Halifax, Nova Scotia. It compares water savings using fixed-outlet and flow-modulated pressure control to performance without pressure control, considering the embedded electricity and chemical consumption in the lost water, manufacture of pipe and fittings to repair breaks caused by excess pressure, and pressure management. The resulting energy and emissions savings are significant. The Philadelphia and Halifax utilities both avoid approximately 130 million liters in water losses annually using flow-modulated pressure management. The conserved energy was 780 GJ and 1900 GJ while avoided greenhouse gas emissions were 50 Mg and 170 Mg a year by Philadelphia and Halifax, respectively. The life-cycle financial and environmental performance of pressure management systems compares favorably to the traditional demand management strategy of installing low-flow toilets. The energy savings may also translate to cost-effective greenhouse gas emission reductions depending on the energy mix used, an important advantage in areas where water and energy are constrained and/or expensive and greenhouse gas emissions are regulated as in California, for example.

Factors Affecting Aerosol Radiative Forcing

NASA Astrophysics Data System (ADS)

Wang, J.; Lin, J.; Ni, R.

2016-12-01

Rapid industrial and economic growth has meant large amount of aerosols in the atmosphere with strong radiative forcing (RF) upon the climate system. Over parts of the globe, the negative forcing of aerosols has overcompensated for the positive forcing of greenhouse gases. Aerosol RF is determined by emissions and various chemical-transport-radiative processes in the atmosphere, a multi-factor problem whose individual contributors have not been well quantified. In this study, we analyze the major factors affecting RF of secondary inorganic aerosols (SIOAs, including sulfate, nitrate and ammonium), primary organic aerosol (POA), and black carbon (BC). We analyze the RFof aerosols produced by 11 major regions across the globe, including but not limited to East Asia, Southeast Asia, South Asia, North America, and Western Europe. Factors analyzed include population size, per capita gross domestic production (GDP), emission intensity (i.e., emissionsper unit GDP), chemical efficiency (i.e., mass per unit emissions) and radiative efficiency (i.e., RF per unit mass). We find that among the 11 regions, East Asia produces the largest emissions and aerosol RF, due to relatively high emission intensity and a tremendous population size.South Asia produce the second largest RF of SIOA and BC and the highest RF of POA, in part due to its highest chemical efficiency among all regions. Although Southeast Asia also has large emissions,its aerosol RF is alleviated by its lowest chemical efficiency.The chemical efficiency and radiative efficiency of BC produced by the Middle East-North Africa are the highest across the regions, whereas its RF is loweredbyasmall per capita GDP.Both North America and Western Europe have low emission intensity, compensating for the effects on RF of large population sizes and per capita GDP. There has been a momentum to transfer industries to Southeast Asia and South Asia, and such transition is expected to continue in the coming years. The resulting relocation of emissions would meant drastic changes in both the spatial distribution and the magnitude of RF, with consequences on regional and global climate forcing. Our findings are relevant to global aerosol control and climate mitigation.

Performance and emission characteristics of the thermal barrier coated SI engine by adding argon inert gas to intake mixture.

PubMed

Karthikeya Sharma, T

2015-11-01

Dilution of the intake air of the SI engine with the inert gases is one of the emission control techniques like exhaust gas recirculation, water injection into combustion chamber and cyclic variability, without scarifying power output and/or thermal efficiency (TE). This paper investigates the effects of using argon (Ar) gas to mitigate the spark ignition engine intake air to enhance the performance and cut down the emissions mainly nitrogen oxides. The input variables of this study include the compression ratio, stroke length, and engine speed and argon concentration. Output parameters like TE, volumetric efficiency, heat release rates, brake power, exhaust gas temperature and emissions of NOx, CO2 and CO were studied in a thermal barrier coated SI engine, under variable argon concentrations. Results of this study showed that the inclusion of Argon to the input air of the thermal barrier coated SI engine has significantly improved the emission characteristics and engine's performance within the range studied.

Gallium Nitride Nanowires and Heterostructures: Toward Color-Tunable and White-Light Sources.

PubMed

Kuykendall, Tevye R; Schwartzberg, Adam M; Aloni, Shaul

2015-10-14

Gallium-nitride-based light-emitting diodes have enabled the commercialization of efficient solid-state lighting devices. Nonplanar nanomaterial architectures, such as nanowires and nanowire-based heterostructures, have the potential to significantly improve the performance of light-emitting devices through defect reduction, strain relaxation, and increased junction area. In addition, relaxation of internal strain caused by indium incorporation will facilitate pushing the emission wavelength into the red. This could eliminate inefficient phosphor conversion and enable color-tunable emission or white-light emission by combining blue, green, and red sources. Utilizing the waveguiding modes of the individual nanowires will further enhance light emission, and the properties of photonic structures formed by nanowire arrays can be implemented to improve light extraction. Recent advances in synthetic methods leading to better control over GaN and InGaN nanowire synthesis are described along with new concept devices leading to efficient white-light emission. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Laser Ablated Carbon Nanodots for Light Emission.

PubMed

Reyes, Delfino; Camacho, Marco; Camacho, Miguel; Mayorga, Miguel; Weathers, Duncan; Salamo, Greg; Wang, Zhiming; Neogi, Arup

2016-12-01

The synthesis of fluorescent carbon dots-like nanostructures (CNDs) obtained through the laser ablation of a carbon solid target in liquid environment is reported. The ablation process was induced in acetone with laser pulses of 1064, 532, and 355 nm under different irradiation times. Close-spherical amorphous CNDs with sizes between 5 and 20 nm, whose abundance strongly depends on the ablation parameters were investigated using electron microscopy and was confirmed using absorption and emission spectroscopies. The π- π* electronic transition at 3.76 eV dominates the absorption for all the CNDs species synthesized under different irradiation conditions. The light emission is most efficient due to excitation at 3.54 eV with the photoluminescence intensity centered at 3.23 eV. The light emission from the CNDs is most efficient due to ablation at 355 nm. The emission wavelength of the CNDs can be tuned from the near-UV to the green wavelength region by controlling the ablation time and modifying the ablation and excitation laser wavelength.

Performance and emission characteristics of the thermal barrier coated SI engine by adding argon inert gas to intake mixture

PubMed Central

Karthikeya Sharma, T.

2014-01-01

Dilution of the intake air of the SI engine with the inert gases is one of the emission control techniques like exhaust gas recirculation, water injection into combustion chamber and cyclic variability, without scarifying power output and/or thermal efficiency (TE). This paper investigates the effects of using argon (Ar) gas to mitigate the spark ignition engine intake air to enhance the performance and cut down the emissions mainly nitrogen oxides. The input variables of this study include the compression ratio, stroke length, and engine speed and argon concentration. Output parameters like TE, volumetric efficiency, heat release rates, brake power, exhaust gas temperature and emissions of NOx, CO2 and CO were studied in a thermal barrier coated SI engine, under variable argon concentrations. Results of this study showed that the inclusion of Argon to the input air of the thermal barrier coated SI engine has significantly improved the emission characteristics and engine’s performance within the range studied. PMID:26644918

Aerial sampling of emissions from biomass pile burns in ...

EPA Pesticide Factsheets

Emissions from burning piles of post-harvest timber slash in Grande Ronde, Oregon were sampled using an instrument platform lofted into the plume using a tether-controlled aerostat or balloon. Emissions of carbon monoxide, carbon dioxide, methane, particulate matter (PM2.5 µm), black carbon, ultraviolet absorbing PM, elemental/organic carbon, semi-volatile organics (polycyclic aromatic hydrocarbons and polychlorinated dibenzodioxins/dibenzofurans), filter-based metals, and volatile organics were sampled for determination of emission factors. The effect on emissions from covering or not covering piles with polyethylene sheets to prevent fuel wetting was determined. Results showed that the uncovered (“wet”) piles burned with lower combustion efficiency and higher emissions of volatile organic compounds. Results for other pollutants will also be discussed. This work determined the emissions from open burning of forest slash wood, with and without plastic sheeting. The foresters advocate the use of plastic to keep the slash wood dry and aid in the controlled combustion of the slash to reduce fuel loading. Concerns about the emissions from the burning plastic prompted this work which conducted an extensive characterization of dry, wet, and dry with plastic slash pile emissions.

Quantifying the efficiency and equity implications of power plant air pollution control strategies in the United States

DOE Office of Scientific and Technical Information (OSTI.GOV)

Levy, J.I.; Wilson, A.M.; Zwack, L.M.

2007-05-15

We modeled the public health benefits and the change in the spatial inequality of health risk for a number of hypothetical control scenarios for power plants in the United States to determine optimal control strategies. We simulated various ways by which emission reductions of sulfur dioxide (SO{sub 2}), nitrogen oxides, and fine particulate matter (PM2.5) could be distributed to reach national emissions caps. We applied a source-receptor matrix to determine the PM2.5 concentration changes associated with each control scenario and estimated the mortality reductions. We estimated changes in the spatial inequality of health risk using the Atkinson index and othermore » indicators, following previously derived axioms for measuring health risk inequality. In our baseline model, benefits ranged from 17,000-21,000 fewer premature deaths per year across control scenarios. Scenarios with greater health benefits also tended to have greater reductions in the spatial inequality of health risk, as many sources with high health benefits per unit emissions of SO{sub 2} were in areas with high background PM2.5 concentrations. Sensitivity analyses indicated that conclusions were generally robust to the choice of indicator and other model specifications. Our analysis demonstrates an approach for formally quantifying both the magnitude and spatial distribution of health benefits of pollution control strategies, allowing for joint consideration of efficiency and equity.« less

40 CFR 63.4181 - What definitions apply to this subpart?

Code of Federal Regulations, 2012 CFR

2012-07-01

... commercial or industrial HVAC systems. Manufacturer's formulation data means data on a material (such as a.... Capture efficiency or capture system efficiency means the portion (expressed as a percentage) of the pollutants from an emission source that is delivered to an add-on control device. Capture system means one or...

40 CFR 63.4181 - What definitions apply to this subpart?

Code of Federal Regulations, 2014 CFR

2014-07-01

... commercial or industrial HVAC systems. Manufacturer's formulation data means data on a material (such as a.... Capture efficiency or capture system efficiency means the portion (expressed as a percentage) of the pollutants from an emission source that is delivered to an add-on control device. Capture system means one or...

40 CFR 63.4181 - What definitions apply to this subpart?

Code of Federal Regulations, 2013 CFR

2013-07-01

... commercial or industrial HVAC systems. Manufacturer's formulation data means data on a material (such as a.... Capture efficiency or capture system efficiency means the portion (expressed as a percentage) of the pollutants from an emission source that is delivered to an add-on control device. Capture system means one or...

40 CFR 52.2220 - Identification of plan.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Coke Battery Underfire (combustion) Stacks 06/07/92 08/15/97, 62 FR 43643 CHAPTER 1200-3-6NON-PROCESS... Compliance Procedures: Emission Capture and Destruction or Removal Efficiency and Monitoring Requirements 05... the Destruction or Removal Efficiency of a Control Device 05/18/93 02/27/95, 60 FR 10504 Section 1200...

40 CFR 52.2220 - Identification of plan.

Code of Federal Regulations, 2014 CFR

2014-07-01

.../06/98 09/16/02, 62 FR 46594 Section 1200-3-5-.12 Coke Battery Underfire (combustion) Stacks 06/07/92... Compliance Procedures: Emission Capture and Destruction or Removal Efficiency and Monitoring Requirements 05... the Destruction or Removal Efficiency of a Control Device 05/18/93 02/27/95, 60 FR 10504 Section 1200...

40 CFR 63.5170 - How do I demonstrate compliance with the standards?

Code of Federal Regulations, 2014 CFR

2014-07-01

... percent on a monthly basis for individual or groups of coil coating lines; or overall organic HAP control... combination of compliant coatings and control devices and maintaining an acceptable equivalent emission rate... facility. (6) Control efficiency calculation of HAP emitted. For each work station or group of work...

40 CFR 63.5170 - How do I demonstrate compliance with the standards?

Code of Federal Regulations, 2012 CFR

2012-07-01

... percent on a monthly basis for individual or groups of coil coating lines; or overall organic HAP control... combination of compliant coatings and control devices and maintaining an acceptable equivalent emission rate... facility. (6) Control efficiency calculation of HAP emitted. For each work station or group of work...

40 CFR 63.5170 - How do I demonstrate compliance with the standards?

Code of Federal Regulations, 2013 CFR

2013-07-01

... percent on a monthly basis for individual or groups of coil coating lines; or overall organic HAP control... combination of compliant coatings and control devices and maintaining an acceptable equivalent emission rate... facility. (6) Control efficiency calculation of HAP emitted. For each work station or group of work...

40 CFR 63.4981 - What definitions apply to this subpart?

Code of Federal Regulations, 2013 CFR

2013-07-01

... subpart are defined in the CAA, in 40 CFR 63.2, and in this section as follows: Add-on control means an air pollution control device such as a thermal oxidizer or carbon adsorber that reduces pollution in... those emissions into an add-on air pollution control device. Capture efficiency or capture system...

40 CFR 63.4981 - What definitions apply to this subpart?

Code of Federal Regulations, 2012 CFR

2012-07-01

... subpart are defined in the CAA, in 40 CFR 63.2, and in this section as follows: Add-on control means an air pollution control device such as a thermal oxidizer or carbon adsorber that reduces pollution in... those emissions into an add-on air pollution control device. Capture efficiency or capture system...

40 CFR 63.4981 - What definitions apply to this subpart?

Code of Federal Regulations, 2014 CFR

2014-07-01

... subpart are defined in the CAA, in 40 CFR 63.2, and in this section as follows: Add-on control means an air pollution control device such as a thermal oxidizer or carbon adsorber that reduces pollution in... those emissions into an add-on air pollution control device. Capture efficiency or capture system...

Diesel fuel burner for diesel emissions control system

DOEpatents

Webb, Cynthia C.; Mathis, Jeffrey A.

2006-04-25

A burner for use in the emissions system of a lean burn internal combustion engine. The burner has a special burner head that enhances atomization of the burner fuel. Its combustion chamber is designed to be submersed in the engine exhaust line so that engine exhaust flows over the outer surface of the combustion chamber, thereby providing efficient heat transfer.

40 CFR Table 27 to Subpart Uuu of... - Continuous Compliance With Inorganic HAP Emission Limits for Catalytic Reforming Units

Code of Federal Regulations, 2013 CFR

2013-07-01

... oxygen. Maintaining a 92 percent HCl emission reduction or an HCl concentration no more than 30 ppmv (dry basis), corrected to 3 percent oxygen. 2. Each existing cyclic or continuous catalytic reforming unit...), corrected to 3 percent oxygen Maintaining a 97 percent HCl control efficiency or an HCl concentration no...

40 CFR Table 27 to Subpart Uuu of... - Continuous Compliance With Inorganic HAP Emission Limits for Catalytic Reforming Units

Code of Federal Regulations, 2012 CFR

2012-07-01

... oxygen. Maintaining a 92 percent HCl emission reduction or an HCl concentration no more than 30 ppmv (dry basis), corrected to 3 percent oxygen. 2. Each existing cyclic or continuous catalytic reforming unit...), corrected to 3 percent oxygen Maintaining a 97 percent HCl control efficiency or an HCl concentration no...

White OLED devices and processes for lighting applications

NASA Astrophysics Data System (ADS)

Ide, Nobuhiro; Tsuji, Hiroya; Ito, Norihiro; Matsuhisa, Yuko; Houzumi, Shingo; Nishimori, Taisuke

2010-05-01

In these days, the basic performances of white OLEDs are dramatically improved and application of OLEDs to "Lighting" is expected to be true in the near future. We have developed various technologies for OLED lighting with the aid of the Japanese governmental project, "High-efficiency lighting based on the organic light-emitting mechanism." In this project, a white OLED with high efficiency (37 lm/W) and high quality emission characteristics (CRI of 95 with a small variation of chromaticity in different directions and chromaticity just on the black-body radiation curve) applicable to "Lighting" was realized by a two-unit structure with a fluorescent deep blue emissive unit and a phosphorescent green and red emissive unit. Half-decay lifetime of this white OLED at 1,000 cd/m2 was over 40,000 h. A heat radiative, thin encapsulation structure (less than 1 mm) realized a very stable emission at high luminance of over 3,000 cd/m2. A new deposition source with a hot-wall and a rate controllable valve was developed. Thickness uniformity within +/- 3% at high deposition rate of over 8 nm/s, high material utilization of over 70 %, and repeatable deposition rate controllability were confirmed.

Control of Nitrogen Dioxide in Stack Emission by Reaction with Ammonia

NASA Technical Reports Server (NTRS)

Metzler, A. J.; Stevenson, E. F.

1970-01-01

The development of an acid base gas-phase reaction system which utilizes anhydrous ammonia as the reactant to remove nitrogen dioxide from hydrazine-nitrogen tetroxide rocket combustion exhaust is reported. This reaction reduced NO2 levels in exhaust emissions so that the resulting stack emission is completely white instead of the earlier observed typical reddish-brown coloration. Preliminary analyses indicate the importance of reaction time and ammonia concentration on removal efficiency and elimination of the health hazard to individuals with respiratory problems.

Premature deaths attributed to source-specific BC emissions in six urban US regions

NASA Astrophysics Data System (ADS)

Turner, Matthew D.; Henze, Daven K.; Capps, Shannon L.; Hakami, Amir; Zhao, Shunliu; Resler, Jaroslav; Carmichael, Gregory R.; Stanier, Charles O.; Baek, Jaemeen; Sandu, Adrian; Russell, Armistead G.; Nenes, Athanasios; Pinder, Rob W.; Napelenok, Sergey L.; Bash, Jesse O.; Percell, Peter B.; Chai, Tianfeng

2015-11-01

Recent studies have shown that exposure to particulate black carbon (BC) has significant adverse health effects and may be more detrimental to human health than exposure to PM2.5 as a whole. Mobile source BC emission controls, mostly on diesel-burning vehicles, have successfully decreased mobile source BC emissions to less than half of what they were 30 years ago. Quantification of the benefits of previous emissions controls conveys the value of these regulatory actions and provides a method by which future control alternatives could be evaluated. In this study we use the adjoint of the Community Multiscale Air Quality (CMAQ) model to estimate highly-resolved spatial distributions of benefits related to emission reductions for six urban regions within the continental US. Emissions from outside each of the six chosen regions account for between 7% and 27% of the premature deaths attributed to exposure to BC within the region. While we estimate that nonroad mobile and onroad diesel emissions account for the largest number of premature deaths attributable to exposure to BC, onroad gasoline is shown to have more than double the benefit per unit emission relative to that of nonroad mobile and onroad diesel. Within the region encompassing New York City and Philadelphia, reductions in emissions from large industrial combustion sources that are not classified as EGUs (i.e., non-EGU) are estimated to have up to triple the benefits per unit emission relative to reductions to onroad diesel sectors, and provide similar benefits per unit emission to that of onroad gasoline emissions in the region. While onroad mobile emissions have been decreasing in the past 30 years and a majority of vehicle emission controls that regulate PM focus on diesel emissions, our analysis shows the most efficient target for stricter controls is actually onroad gasoline emissions.

Restaurant emissions removal by a biofilter with immobilized bacteria*

PubMed Central

Miao, Jian-yu; Zheng, Lian-ying; Guo, Xiao-fen

2005-01-01

Pseudomonas sp. ZD8 isolated from contaminated soil was immobilized with platane wood chips to produce packing materials for a novel biofilter system utilized to control restaurant emissions. The effects of operational parameters including retention time, temperature, and inlet gas concentration on the removal efficiency and elimination capacity were evaluated. Criteria necessary for a scale-up design of the biofilter was established. High and satisfactory level of rapeseed oil smoke removal efficiency was maintained during operation and the optimal retention time was found to be 18 s corresponding to smoke removal efficiency greater than 97%. The optimal inlet rapeseed oil smoke loading was 120 mg/(m3·h) at the upper end of the linear correlation between inlet loading and elimination capacity. PMID:15822160

Restaurant emissions removal by a biofilter with immobilized bacteria.

PubMed

Miao, Jian-Yu; Zheng, Lian-Ying; Guo, Xiao-Fen

2005-05-01

Pseudomonas sp. ZD8 isolated from contaminated soil was immobilized with platane wood chips to produce packing materials for a novel biofilter system utilized to control restaurant emissions. The effects of operational parameters including retention time, temperature, and inlet gas concentration on the removal efficiency and elimination capacity were evaluated. Criteria necessary for a scale-up design of the biofilter was established. High and satisfactory level of rapeseed oil smoke removal efficiency was maintained during operation and the optimal retention time was found to be 18 s corresponding to smoke removal efficiency greater than 97%. The optimal inlet rapeseed oil smoke loading was 120 mg/(m(3) x h) at the upper end of the linear correlation between inlet loading and elimination capacity.

Evaluation of a novel wind tunnel for the measurement of the kinetics of odour emissions from piggery effluent.

PubMed

Sohn, J H; Smith, R; Yoong, E; Hudson, N; Kim, T I

2004-01-01

A novel laboratory wind tunnel, with the capability to control factors such as air flow-rate, was developed to measure the kinetics of odour emissions from liquid effluent. The tunnel allows the emission of odours and other volatiles under an atmospheric transport system similar to ambient conditions. Sensors for wind speed, temperature and humidity were installed and calibrated. To calibrate the wind tunnel, trials were performed to determine the gas recovery efficiency under different air flow-rates (ranging from 0.001 to 0.028m3/s) and gas supply rates (ranging from 2.5 to 10.0 L/min) using a standard CO gas mixture. The results have shown gas recovery efficiencies ranging from 61.7 to 106.8%, while the average result from the trials was 81.14%. From statistical analysis, it was observed that the highest, most reliable gas recovery efficiency of the tunnel was 88.9%. The values of air flow-rate and gas supply rate corresponding to the highest gas recovery efficiency were 0.028 m3/s and 10.0 L/min respectively. This study suggested that the wind tunnel would provide precise estimates of odour emission rate. However, the wind tunnel needs to be calibrated to compensate for errors caused by different air flow-rates.

Highly Efficient Spectrally Stable Red Perovskite Light-Emitting Diodes.

PubMed

Tian, Yu; Zhou, Chenkun; Worku, Michael; Wang, Xi; Ling, Yichuan; Gao, Hanwei; Zhou, Yan; Miao, Yu; Guan, Jingjiao; Ma, Biwu

2018-05-01

Perovskite light-emitting diodes (LEDs) have recently attracted great research interest for their narrow emissions and solution processability. Remarkable progress has been achieved in green perovskite LEDs in recent years, but not blue or red ones. Here, highly efficient and spectrally stable red perovskite LEDs with quasi-2D perovskite/poly(ethylene oxide) (PEO) composite thin films as the light-emitting layer are reported. By controlling the molar ratios of organic salt (benzylammonium iodide) to inorganic salts (cesium iodide and lead iodide), luminescent quasi-2D perovskite thin films are obtained with tunable emission colors from red to deep red. The perovskite/polymer composite approach enables quasi-2D perovskite/PEO composite thin films to possess much higher photoluminescence quantum efficiencies and smoothness than their neat quasi-2D perovskite counterparts. Electrically driven LEDs with emissions peaked at 638, 664, 680, and 690 nm have been fabricated to exhibit high brightness and external quantum efficiencies (EQEs). For instance, the perovskite LED with an emission peaked at 680 nm exhibits a brightness of 1392 cd m -2 and an EQE of 6.23%. Moreover, exceptional electroluminescence spectral stability under continuous device operation has been achieved for these red perovskite LEDs. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

White-Light Emission from Layered Halide Perovskites.

PubMed

Smith, Matthew D; Karunadasa, Hemamala I

2018-03-20

With nearly 20% of global electricity consumed by lighting, more efficient illumination sources can enable massive energy savings. However, effectively creating the high-quality white light required for indoor illumination remains a challenge. To accurately represent color, the illumination source must provide photons with all the energies visible to our eye. Such a broad emission is difficult to achieve from a single material. In commercial white-light sources, one or more light-emitting diodes, coated by one or more phosphors, yield a combined emission that appears white. However, combining emitters leads to changes in the emission color over time due to the unequal degradation rates of the emitters and efficiency losses due to overlapping absorption and emission energies of the different components. A single material that emits broadband white light (a continuous emission spanning 400-700 nm) would obviate these problems. In 2014, we described broadband white-light emission upon near-UV excitation from three new layered perovskites. To date, nine white-light-emitting perovskites have been reported by us and others, making this a burgeoning field of study. This Account outlines our work on understanding how a bulk material, with no obvious emissive sites, can emit every color of the visible spectrum. Although the initial discoveries were fortuitous, our understanding of the emission mechanism and identification of structural parameters that correlate with the broad emission have now positioned us to design white-light emitters. Layered hybrid halide perovskites feature anionic layers of corner-sharing metal-halide octahedra partitioned by organic cations. The narrow, room-temperature photoluminescence of lead-halide perovskites has been studied for several decades, and attributed to the radiative recombination of free excitons (excited electron-hole pairs). We proposed that the broad white emission we observed primarily stems from exciton self-trapping. Here, the exciton couples strongly to the lattice, creating transient elastic lattice distortions that can be viewed as "excited-state defects". These deformations stabilize the exciton affording a broad emission with a large Stokes shift. Although material defects very likely contribute to the emission width, our mechanistic studies suggest that the emission mostly arises from the bulk material. Ultrafast spectroscopic measurements support self-trapping, with new, transient, electronic states appearing upon photoexcitation. Importantly, the broad emission appears common to layered Pb-Br and Pb-Cl perovskites, albeit with a strong temperature dependence. Although the emission is attributed to light-induced defects, it still reflects changes in the crystal structure. We find that greater out-of-plane octahedral tilting increases the propensity for the broad emission, enabling synthetic control over the broad emission. Many of these perovskites have color rendering abilities that exceed commercial requirements and mixing halides affords both "warm" and "cold" white light. The most efficient white-light-emitting perovskite has a quantum efficiency of 9%. Improving this value will make these phosphors attractive for solid-state lighting, particularly as large-area coatings that can be deposited inexpensively. The emission mechanism can also be extended to other low-dimensional systems. We hope this Account aids in expanding the phase space of white-light emitters and controlling their exciton dynamics by the synthetic, spectroscopic, theoretical, and engineering communities.

Water Injection Feasibility for Boeing 747 Aircraft

NASA Technical Reports Server (NTRS)

Daggett, David L.

2005-01-01

Can water injection be offered at a reasonable cost to large airplane operators to reduce takeoff NO( sub x) emissions? This study suggests it may be possible. This report is a contract deliverable to NASA Glenn Research Center from the prime contractor, The Boeing Commercial Airplane Company of Seattle, WA. This study was supported by a separate contract to the Pratt & Whitney Engine Company of Hartford, CT (contract number NNC04QB58P). Aviation continues to grow and with it, environmental pressures are increasing for airports that service commercial airplanes. The feasibility and performance of an emissions-reducing technology, water injection, was studied for a large commercial airplane (e.g., Boeing 747 with PW4062 engine). The primary use of the water-injection system would be to lower NOx emissions while an important secondary benefit might be to improve engine turbine life. A tradeoff exists between engine fuel efficiency and NOx emissions. As engines improve fuel efficiency, by increasing the overall pressure ratio of the engine s compressor, the resulting increased gas temperature usually results in higher NOx emissions. Low-NO(sub x) combustors have been developed for new airplanes to control the increases in NO(sub x) emissions associated with higher efficiency, higher pressure ratio engines. However, achieving a significant reduction of NO(sub x) emissions at airports has been challenging. Using water injection during takeoff has the potential to cut engine NO(sub x) emissions some 80 percent. This may eliminate operating limitations for airplanes flying into airports with emission constraints. This study suggests an important finding of being able to offer large commercial airplane owners an emission-reduction technology that may also save on operating costs.

Evaluating efficiency-equality tradeoffs for mobile source control strategies in an urban area

PubMed Central

Levy, Jonathan I.; Greco, Susan L.; Melly, Steven J.; Mukhi, Neha

2013-01-01

In environmental risk management, there are often interests in maximizing public health benefits (efficiency) and addressing inequality in the distribution of health outcomes. However, both dimensions are not generally considered within a single analytical framework. In this study, we estimate both total population health benefits and changes in quantitative indicators of health inequality for a number of alternative spatial distributions of diesel particulate filter retrofits across half of an urban bus fleet in Boston, Massachusetts. We focus on the impact of emissions controls on primary fine particulate matter (PM2.5) emissions, modeling the effect on PM2.5 concentrations and premature mortality. Given spatial heterogeneity in baseline mortality rates, we apply the Atkinson index and other inequality indicators to quantify changes in the distribution of mortality risk. Across the different spatial distributions of control strategies, the public health benefits varied by more than a factor of two, related to factors such as mileage driven per day, population density near roadways, and baseline mortality rates in exposed populations. Changes in health inequality indicators varied across control strategies, with the subset of optimal strategies considering both efficiency and equality generally robust across different parametric assumptions and inequality indicators. Our analysis demonstrates the viability of formal analytical approaches to jointly address both efficiency and equality in risk assessment, providing a tool for decision-makers who wish to consider both issues. PMID:18793281

Solid state carbon nanotube device for controllable trion electroluminescence emission

NASA Astrophysics Data System (ADS)

Liang, Shuang; Ma, Ze; Wei, Nan; Liu, Huaping; Wang, Sheng; Peng, Lian-Mao

2016-03-01

Semiconducting carbon nanotubes (CNTs) have a direct chirality-dependent bandgap and reduced dimensionality-related quantum confinement effects, which are closely related to the performance of optoelectronic devices. Here, taking advantage of the large energy separations between neutral singlet excitons and charged excitons, i.e. trions in CNTs, we have achieved for the first time all trion electroluminescence (EL) emission from chirality-sorted (8,3) and (8,4) CNT-based solid state devices. We showed that strong trion emission can be obtained as a result of localized impact excitation and electrically injected holes, with an estimated efficiency of ~5 × 10-4 photons per injected hole. The importance of contact-controlled carrier injection (including symmetric and asymmetric contact configurations) and EL spectral stability for gradually increasing bias were also investigated. The realization of electrically induced pure trion emission opens up a new opportunity for CNT film-based optoelectronic devices, providing a new degree of freedom in controlling the devices to extend potential applications in spin or magnetic optoelectronics fields.Semiconducting carbon nanotubes (CNTs) have a direct chirality-dependent bandgap and reduced dimensionality-related quantum confinement effects, which are closely related to the performance of optoelectronic devices. Here, taking advantage of the large energy separations between neutral singlet excitons and charged excitons, i.e. trions in CNTs, we have achieved for the first time all trion electroluminescence (EL) emission from chirality-sorted (8,3) and (8,4) CNT-based solid state devices. We showed that strong trion emission can be obtained as a result of localized impact excitation and electrically injected holes, with an estimated efficiency of ~5 × 10-4 photons per injected hole. The importance of contact-controlled carrier injection (including symmetric and asymmetric contact configurations) and EL spectral stability for gradually increasing bias were also investigated. The realization of electrically induced pure trion emission opens up a new opportunity for CNT film-based optoelectronic devices, providing a new degree of freedom in controlling the devices to extend potential applications in spin or magnetic optoelectronics fields. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr07468a

Vertical pillar nanoantenna for emission enhancement and redirection

NASA Astrophysics Data System (ADS)

Paparone, J.; Laverdant, J.; Brucoli, G.; Symonds, C.; Crut, A.; Del Fatti, N.; Benoit, J. M.; Bellessa, J.

2018-01-01

Designing efficient metallic nanostructures can help in realizing bright single photon emission in the visible and near-infrared ranges. We propose a novel nanostructure design that combines the benefits of plasmonic hot spot generation in the near-field and the concept of antennas developed in the radio-frequency range. The antenna is formed by a vertical stack of metallic and dielectric nanocylinders. When used for controlling the far-field emission of a localized source, its key features are moderate losses in the metal, relatively large Purcell factors, as well as a low sensibility to the lateral position of the emitter. A redirection process necessary for these vertical structures is proposed, based on the versatility of the vertical geometry, and allows an efficient redirection of the emitted light even for antennas on dielectric substrates.

NETL - Thermogravimetric Analysis Laboratory

ScienceCinema

Richards, George

2018-06-22

Researchers in NETL's Thermal Analysis Laboratory are investigating chemical looping combustion. As a clean and efficient fossil fuel technology, chemical looping combustion controls CO2 emissions and offers a promising alternative to traditional combustion.

GHG emissions during the high-rate production of compost using standard and advanced aeration strategies.

PubMed

Puyuelo, B; Gea, T; Sánchez, A

2014-08-01

In this study, we have evaluated different strategies for the optimization of the aeration during the active thermophilic stage of the composting process of source-selected Organic Fraction of Municipal Solid Waste (or biowaste) using reactors at bench scale (50L). These strategies include: typical cyclic aeration, oxygen feedback controller and a new self-developed controller based on the on-line maximization of the oxygen uptake rate (OUR) during the process. Results highlight differences found in the emission of most representative greenhouse gases (GHG) emitted from composting (methane and nitrous oxide) as well as in gases typically related to composting odor problems (ammonia as typical example). Specifically, the cyclic controller presents emissions that can double that of OUR controller, whereas oxygen feedback controller shows a better performance with respect to the cyclic controller. A new parameter, the respiration index efficiency, is presented to quantitatively evaluate the GHG emissions and, in consequence, the main negative environmental impact of the composting process. Other aspects such as the stability of the compost produced and the consumption of resources are also evaluated for each controller. Copyright © 2014 Elsevier Ltd. All rights reserved.

Intelligent Bioreactor Management Information System (IBM-IS) for Mitigation of Greenhouse Gas Emissions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paul Imhoff; Ramin Yazdani; Don Augenstein

Methane is an important contributor to global warming with a total climate forcing estimated to be close to 20% that of carbon dioxide (CO2) over the past two decades. The largest anthropogenic source of methane in the US is 'conventional' landfills, which account for over 30% of anthropogenic emissions. While controlling greenhouse gas emissions must necessarily focus on large CO2 sources, attention to reducing CH4 emissions from landfills can result in significant reductions in greenhouse gas emissions at low cost. For example, the use of 'controlled' or bioreactor landfilling has been estimated to reduce annual US greenhouse emissions by aboutmore » 15-30 million tons of CO2 carbon (equivalent) at costs between $3-13/ton carbon. In this project we developed or advanced new management approaches, landfill designs, and landfill operating procedures for bioreactor landfills. These advances are needed to address lingering concerns about bioreactor landfills (e.g., efficient collection of increased CH4 generation) in the waste management industry, concerns that hamper bioreactor implementation and the consequent reductions in CH4 emissions. Collectively, the advances described in this report should result in better control of bioreactor landfills and reductions in CH4 emissions. Several advances are important components of an Intelligent Bioreactor Management Information System (IBM-IS).« less

Biofiltration: an innovative air pollution control technology for VOC emissions.

PubMed

Leson, G; Winer, A M

1991-08-01

Biofiltration is a relatively recent air pollution control (APC) technology in which off-gases containing biodegradable volatile organic compounds (VOC) or inorganic air toxics are vented through a biologically active material. This technology has been successfully applied in Germany and The Netherlands in many full-scale applications to control odors, VOC and air toxic emissions from a wide range of industrial and public sector sources. Control efficiencies of more than 90 percent have been achieved for many common air pollutants. Due to lower operating costs, biofiltration can provide significant economic advantages over other APC technologies if applied to off-gases that contain readily biodegradable pollutants in low concentrations. Environmental benefits include low energy requirements and the avoidance of cross media transfer of pollutants. This paper reviews the history and current status of biofiltration, outlines its underlying scientific and engineering principles, and discusses the applicability of biofilters for a wide range of specific emission sources.

Will joint regional air pollution control be more cost-effective? An empirical study of China's Beijing-Tianjin-Hebei region.

PubMed

Wu, Dan; Xu, Yuan; Zhang, Shiqiu

2015-02-01

By following an empirical approach, this study proves that joint regional air pollution control (JRAPC) in the Beijing-Tianjin-Hebei region will save the expense on air pollution control compared with a locally-based pollution control strategy. The evidences below were found. (A) Local pollutant concentration in some of the cities is significantly affected by emissions from their surrounding areas. (B) There is heterogeneity in the marginal pollutant concentration reduction cost among various districts as a result of the cities' varying contribution of unit emission reduction to the pollutant concentration reduction, and their diverse unit cost of emission reduction brought about by their different industry composition. The results imply that the cost-efficiency of air pollution control will be improved in China if the conventional locally based regime of air pollution control can shift to a regionally based one. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

40 CFR Table 4 to Subpart Kkkk of... - Operating Limits If Using the Emission Rate With Add-on Controls Option or the Control Efficiency...

Code of Federal Regulations, 2010 CFR

2010-07-01

... outlet at or below the temperature limit. 6. Concentrators, including zeolite wheels and rotary carbon.... Collecting the temperature data including zeolite inlet temperature according to § 63.3547(f)ii. Reducing the...

Benefits of Improved HP Turbine Active Clearance Control

NASA Technical Reports Server (NTRS)

Ruiz, Rafael; Albers, Bob; Sak, Wojciech; Seitzer, Ken; Steinetz, Bruce M.

2007-01-01

As part of the NASA Propulsion 21 program, GE Aircraft Engines was contracted to develop an improved high pressure turbine(HPT) active clearance control (ACC) system. The system is envisioned to minimize blade tip clearances to improve HPT efficiency throughout the engine operation range simultaneously reducing fuel consumption and emissions.

Energy Extra

ERIC Educational Resources Information Center

CEFP Journal, 1978

1978-01-01

Summarizes findings of an experimental research program to provide a controlled and documented evaluation of the effectiveness of proprietary combustion-type fuel-oil additives and pure compounds for reducing air pollutant emissions and for increasing boiler efficiency. (Author/MLF)

Strong plasmonic enhancement of biexciton emission: controlled coupling of a single quantum dot to a gold nanocone antenna

DOE PAGES

Matsuzaki, Korenobu; Vassant, Simon; Liu, Hsuan-Wei; ...

2017-02-14

Multiexcitonic transitions and emission of several photons per excitation comprise a very attractive feature of semiconductor quantum dots for optoelectronics applications. However, these higher-order radiative processes are usually quenched in colloidal quantum dots by Auger and other nonradiative decay channels. To increase the multiexcitonic quantum efficiency, several groups have explored plasmonic enhancement, so far with moderate results. By controlled positioning of individual quantum dots in the near field of gold nanocone antennas, we enhance the radiative decay rates of monoexcitons and biexcitons by 109 and 100 folds at quantum efficiencies of 60 and 70%, respectively, in very good agreement withmore » the outcome of numerical calculations. We discuss the implications of our work for future fundamental and applied research in nano-optics.« less

Boiler house modernization through shared savings program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Breault, R.W.

1995-12-31

Throughout Poland as well as the rest of Eastern Europe, communities and industries rely on small heat only boilers to provide district and process heat. Together these two sectors produce about 85,000 MW from boilers in the 2 to 35 MW size range. The bulk of these units were installed prior to 1992 and must be completely overhauled to meet the emission regulations which will be coming into effect on January 1, 1998. Since the only practical fuel is coal in most cases, these boilers must be either retrofit with emission control technology or be replaced entirely. The question thatmore » arises is how to accomplish this given the current tight control of capital in Poland and other East European countries. A solution that we have for this problem is shared savings. These boilers are typically operating with a quiet low efficiency as compared to western standards and with excessive manual labor. Installing modernization equipment to improve the efficiency and to automate the process provides savings. ECOGY provides the funds for the modernization to improve the efficiency, add automation and install emission control equipment. The savings that are generated during the operation of the modernized boiler system are split between the client company and ECOGY for a number of years and then the system is turned over in entirety to the client. Depending on the operating capacity, the shared savings agreement will usually span 6 to 10 years.« less

Transportation and Greenhouse Gas Emissions Trading. Final Technical Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steve Winkelman; Tim Hargrave; Christine Vanderlan

1999-10-01

The authors conclude in this report that an upstream system would ensure complete regulatory coverage of transportation sector emissions in an efficient and feasible manner, and as such represents a key component of a national least-cost GHG emissions abatement strategy. The broad coverage provided by an upstream system recommends this approach over vehicle-maker based approaches, which would not cover emissions from heavy-duty vehicles and the aviation, marine and off-road sub-sectors. The on-road fleet approach unfairly and inefficiently burdens vehicle manufacturers with responsibility for emissions that they cannot control. A new vehicles approach would exclude emissions from vehicles on the roadmore » prior to program inception. The hybrid approach faces significant technical and political complications, and it is not clear that the approach would actually change behavior among vehicle makers and users, which is its main purpose. They also note that a trading system would fail to encourage many land use and infrastructure measures that affect VMT growth and GHG emissions. They recommend that this market failure be addressed by complementing the trading system with a program specifically targeting land use- and infrastructure-related activities. A key issue that must be addressed in designing a national GHG control strategy is whether or not it is necessary to guarantee GHG reductions from the transport sector. Neither an upstream system nor a downstream approach would do so, since both would direct capital to the least-cost abatement opportunities wherever they were found. They review two reasons why it may be desirable to force transportation sector reductions: first, that the long-term response to climate change will require reductions in all sectors; and second, the many ancillary benefits associated with transportation-related, and especially VMT-related, emissions reduction activities. If policy makers find it desirable to establish transportation-specific policies, they recommend (in addition to the land use policies mentioned above), that they combine an upstream trading system with a carbon efficiency standard similar to the current CAFE standard. Under this approach a fuel price signal would be complemented by incentives for manufacturers to produce more carbon efficient vehicles. To prevent vehicle manufacturers from being forced to pay more than other sectors for reducing GHG emissions, they recommend that the vehicle makers be allowed to pay a cash penalty equal to the market price of allowances in lieu of meeting carbon efficiency requirements.« less

Adoption of Emissions Abating Technologies by U.S. Electricity Producing Firms Under the SO2 Emission Allowance Market

NASA Astrophysics Data System (ADS)

Creamer, Gregorio Bernardo

The objective of this research is to determine the adaptation strategies that coal-based, electricity producing firms in the United States utilize to comply with the emission control regulations imposed by the SO2 Emissions Allowance Market created by the Clean Air Act Amendment of 1990, and the effect of market conditions on the decision making process. In particular, I take into consideration (1) the existence of carbon contracts for the provision of coal that may a affect coal prices at the plant level, and (2) local and geographical conditions, as well as political arrangements that may encourage firms to adopt strategies that appear socially less efficient. As the electricity producing sector is a regulated sector, firms do not necessarily behave in a way that maximizes the welfare of society when reacting to environmental regulations. In other words, profit maximization actions taken by the firm do not necessarily translate into utility maximization for society. Therefore, the environmental regulator has to direct firms into adopting strategies that are socially efficient, i.e., that maximize utility. The SO 2 permit market is an instrument that allows each firm to reduce marginal emissions abatement costs according to their own production conditions and abatement costs. Companies will be driven to opt for a cost-minimizing emissions abatement strategy or a combination of abatement strategies when adapting to new environmental regulations or markets. Firms may adopt one or more of the following strategies to reduce abatement costs while meeting the emission constraints imposed by the SO2 Emissions Allowance Market: (1) continue with business as usual on the production site while buying SO2 permits to comply with environmental regulations, (2) switch to higher quality, lower sulfur coal inputs that will generate less SO2 emissions, or (3) adopting new emissions abating technologies. A utility optimization condition is that the marginal value of each input should be equal to the product generated by using it and to the activities that are required by new regulations. The comparative technological and scale efficiency factors of coal-based electricity producing plants are calculated using the Data Envelopment Analysis (DEA) framework, and used as proxies to test this condition. In the empirical analysis, econometric models of the response of firms to emissions control are analyzed around the following aspects: (1) characterization of the behavior of firms and their efficiency, (2) relevant variables that trigger the adoption of technology, that is, the acquisition of scrubbers , and (3) the influence of exogenous variables, such as the existence of contracts, distance from mine to plant, and local conditions of the region where plants are located.

Constructing a sustainable power sector in China: current and future emissions of coal-fired power plants from 2010 to 2030

NASA Astrophysics Data System (ADS)

Tong, D.; Zhang, Q.

2017-12-01

As the largest energy infrastructure in China, power sector consumed more coal than any other sector and threatened air quality and greenhouse gas (GHG) abatement target. In this work, we assessed the evolution of coal-fired power plants in China during 2010-2030 and the evolution of associated emissions for the same period by using a unit-based emission projection model which integrated the historical power plants information, turnover of the future power plant fleet, and the evolution of end-of-pipe control technologies. We found that, driven by the stringent environmental legislation, SO2, NOx, and PM2.5 emissions from China's coal-fired power plants decreased by 49%, 45%, and 24% respectively during 2010-2015, comparing to 14% increase of coal consumption and 15% increase in CO2 emissions. We estimated that under current national energy development planning, coal consumption and CO2 emissions from coal-fired power plants will continue to increase until 2030, in which against the China's Intended Nationally Determined Contributions (INDCs) targets. Early retirement of old and low-efficient power plants will cumulatively reduce 2.2 Pg CO2 emissions from the baseline scenario during 2016-2030, but still could not curb CO2 emissions from the peak before 2030. Owing to the implementation of "near zero" emission control policy, we projected that emissions of air pollutants will significantly decrease during the same period under all scenarios, indicating the decoupling trends of air pollutants and CO2 emissions. Although with limited direct emission reduction benefits, increasing operating hours of power plants could avoid 236 GW of new power plants construction, which could indirectly reduce emissions embodied in the construction activity. Our results identified a more sustainable pathway for China's coal-fired power plants, which could reduce air pollutant emissions, improve the energy efficiency, and slow down the construction of new units. However, continuous construction of new coal-fired power plants driven by increased electricity demand would pose a potential threat to climate change mitigation and China's peak carbon pledge, and more aggressive CO2 emission reduction policy should be implemented in the future.

Atmospheric pollution reduction effect and regional predicament: An empirical analysis based on the Chinese provincial NOx emissions.

PubMed

Ding, Lei; Liu, Chao; Chen, Kunlun; Huang, Yalin; Diao, Beidi

2017-07-01

Atmospheric pollution emissions have become a matter of public concern in recent years. However, most of the existing researches on NOx pollution are from the natural science and technology perspective, few studies have been conducted from an economic point, and regional differences have not been given adequate attention. This paper adopts provincial panel data from 2006 to 2013 and the LMDI model to analyze the key driving factors and regional dilemmas of NOx emissions. The results show that significant regional disparities still exit on NO x emissions and its reduction effect 27 provinces didn't accomplish their corresponding reduction targets. Economic development factor is the dominating driving factor of NO x emissions during the study period, while energy efficiency and technology improvement factors offset total NO x emissions in the majority of provinces. In addition, the industrial structure factor plays a more significant role in reducing the NO x emissions after 2011. Therefore, the government should consider all these factors as well as regional heterogeneity in developing appropriate pollution mitigating policies. It's necessary to change NOx emissions control attitude from original key areas control to divided-zone control, not only attaches great importance to the reduction of the original key areas, but also emphasizes the new potential hotspots with high NO x emissions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Frequency Control of Single Quantum Emitters in Integrated Photonic Circuits

NASA Astrophysics Data System (ADS)

Schmidgall, Emma R.; Chakravarthi, Srivatsa; Gould, Michael; Christen, Ian R.; Hestroffer, Karine; Hatami, Fariba; Fu, Kai-Mei C.

2018-02-01

Generating entangled graph states of qubits requires high entanglement rates, with efficient detection of multiple indistinguishable photons from separate qubits. Integrating defect-based qubits into photonic devices results in an enhanced photon collection efficiency, however, typically at the cost of a reduced defect emission energy homogeneity. Here, we demonstrate that the reduction in defect homogeneity in an integrated device can be partially offset by electric field tuning. Using photonic device-coupled implanted nitrogen vacancy (NV) centers in a GaP-on-diamond platform, we demonstrate large field-dependent tuning ranges and partial stabilization of defect emission energies. These results address some of the challenges of chip-scale entanglement generation.

Frequency Control of Single Quantum Emitters in Integrated Photonic Circuits.

PubMed

Schmidgall, Emma R; Chakravarthi, Srivatsa; Gould, Michael; Christen, Ian R; Hestroffer, Karine; Hatami, Fariba; Fu, Kai-Mei C

2018-02-14

Generating entangled graph states of qubits requires high entanglement rates with efficient detection of multiple indistinguishable photons from separate qubits. Integrating defect-based qubits into photonic devices results in an enhanced photon collection efficiency, however, typically at the cost of a reduced defect emission energy homogeneity. Here, we demonstrate that the reduction in defect homogeneity in an integrated device can be partially offset by electric field tuning. Using photonic device-coupled implanted nitrogen vacancy (NV) centers in a GaP-on-diamond platform, we demonstrate large field-dependent tuning ranges and partial stabilization of defect emission energies. These results address some of the challenges of chip-scale entanglement generation.

Increasing beef production could lower greenhouse gas emissions in Brazil if decoupled from deforestation

NASA Astrophysics Data System (ADS)

de Oliveira Silva, R.; Barioni, L. G.; Hall, J. A. J.; Folegatti Matsuura, M.; Zanett Albertini, T.; Fernandes, F. A.; Moran, D.

2016-05-01

Recent debate about agricultural greenhouse gas emissions mitigation highlights trade-offs inherent in the way we produce and consume food, with increasing scrutiny on emissions-intensive livestock products. Although most research has focused on mitigation through improved productivity, systemic interactions resulting from reduced beef production at the regional level are still unexplored. A detailed optimization model of beef production encompassing pasture degradation and recovery processes, animal and deforestation emissions, soil organic carbon (SOC) dynamics and upstream life-cycle inventory was developed and parameterized for the Brazilian Cerrado. Economic return was maximized considering two alternative scenarios: decoupled livestock-deforestation (DLD), assuming baseline deforestation rates controlled by effective policy; and coupled livestock-deforestation (CLD), where shifting beef demand alters deforestation rates. In DLD, reduced consumption actually leads to less productive beef systems, associated with higher emissions intensities and total emissions, whereas increased production leads to more efficient systems with boosted SOC stocks, reducing both per kilogram and total emissions. Under CLD, increased production leads to 60% higher emissions than in DLD. The results indicate the extent to which deforestation control contributes to sustainable intensification in Cerrado beef systems, and how alternative life-cycle analytical approaches result in significantly different emission estimates.

Contactless electric igniter for vehicle to lower exhaust emission and fuel consumption.

PubMed

Shen, Chih-Lung; Su, Jye-Chau

2014-01-01

An electric igniter for engine/hybrid vehicles is presented. The igniter comprises a flyback converter, a voltage-stacked capacitor, a PIC-based controller, a differential voltage detector, and an ignition coil, of which structure is non-contact type. Since the electric igniter adopts a capacitor to accumulate energy for engine ignition instead of traditional contacttype approach, it enhances the igniting performance of a spark plug effectively. As a result, combustion efficiency is promoted, fuel consumption is saved, and exhaust emission is reduced. The igniter not only is good for fuel efficiency but also can reduce HC and CO emission significantly, which therefore is an environmentally friendly product. The control core of the igniter is implemented on a single chip, which lowers discrete component count, reduces system volume, and increases reliability. In addition, the ignition timing can be programmed so that a timing regulator can be removed from the proposed system, simplifying its structure. To verify the feasibility and functionality of the igniter, key waveforms are measured and real-car experiments are performed as well.

Contactless Electric Igniter for Vehicle to Lower Exhaust Emission and Fuel Consumption

PubMed Central

Su, Jye-Chau

2014-01-01

An electric igniter for engine/hybrid vehicles is presented. The igniter comprises a flyback converter, a voltage-stacked capacitor, a PIC-based controller, a differential voltage detector, and an ignition coil, of which structure is non-contact type. Since the electric igniter adopts a capacitor to accumulate energy for engine ignition instead of traditional contacttype approach, it enhances the igniting performance of a spark plug effectively. As a result, combustion efficiency is promoted, fuel consumption is saved, and exhaust emission is reduced. The igniter not only is good for fuel efficiency but also can reduce HC and CO emission significantly, which therefore is an environmentally friendly product. The control core of the igniter is implemented on a single chip, which lowers discrete component count, reduces system volume, and increases reliability. In addition, the ignition timing can be programmed so that a timing regulator can be removed from the proposed system, simplifying its structure. To verify the feasibility and functionality of the igniter, key waveforms are measured and real-car experiments are performed as well. PMID:24672372

Injection system used into SI engines for complete combustion and reduction of exhaust emissions in the case of alcohol and petrol alcohol mixtures feed

NASA Astrophysics Data System (ADS)

Ispas, N.; Cofaru, C.; Aleonte, M.

2017-10-01

Internal combustion engines still play a major role in today transportation but increasing the fuel efficiency and decreasing chemical emissions remain a great goal of the researchers. Direct injection and air assisted injection system can improve combustion and can reduce the concentration of the exhaust gas pollutes. Advanced air-to-fuel and combustion air-to-fuel injection system for mixtures, derivatives and alcohol gasoline blends represent a major asset in reducing pollutant emissions and controlling combustion processes in spark-ignition engines. The use of these biofuel and biofuel blending systems for gasoline results in better control of spark ignition engine processes, making combustion as complete as possible, as well as lower levels of concentrations of pollutants in exhaust gases. The main purpose of this paper was to provide most suitable tools for ensure the proven increase in the efficiency of spark ignition engines, making them more environmentally friendly. The conclusions of the paper allow to highlight the paths leading to a better use of alcohols (biofuels) in internal combustion engines of modern transport units.

Progress in Emission Efficiency of Organic Light-Emitting Diodes: Basic Understanding and Its Technical Application

NASA Astrophysics Data System (ADS)

Tsutsui, Tetsuo; Takada, Noriyuki

2013-11-01

The technical history of when and how the basic understanding of the emission efficiency of organic light-emitting diodes (OLEDs) was established over the last 50 years is described. At first, our understanding of emission efficiency in single-crystal and thin-film electroluminescence (EL) devices in the early stages before the Eastman-Kodak breakthrough, that is, the introduction of the concept of multilayer structures, is examined. Then our contemplation travels from the Eastman-Kodak breakthrough towards the presently widely accepted concept of emission efficiency. The essential issues concerning the emission efficiency of OLEDs are summarized to help readers to obtain a common understanding of OLED efficiency problems, and detailed discussions on the primary factors that determine emission efficiency are given. Finally, some comments on remaining issues are presented.

Controlling urban air pollution caused by households: uncertainty, prices, and income.

PubMed

Chávez, Carlos A; Stranlund, John K; Gómez, Walter

2011-10-01

We examine the control of air pollution caused by households burning wood for heating and cooking in the developing world. Since the problem is one of controlling emissions from nonpoint sources, regulations are likely to be directed at household choices of wood consumption and combustion technologies. Moreover, these choices are subtractions from, or contributions to, the pure public good of air quality. Consequently, the efficient policy design is not independent of the distribution of household income. Since it is unrealistic to assume that environmental authorities can make lump sum income transfers part of control policies, efficient control of air pollution caused by wood consumption entails a higher tax on wood consumption and a higher subsidy for more efficient combustion technologies for higher income households. Among other difficulties, implementing a policy to promote the adoption of cleaner combustion technologies must overcome the seemingly paradoxical result that efficient control calls for higher technology subsidies for higher income households. Copyright © 2011 Elsevier Ltd. All rights reserved.

Brayton-cycle solvent recovery heat pump. A technical brief

NASA Astrophysics Data System (ADS)

1994-11-01

The US Department of Energy's (DOE's) Office of Industrial Technologies (OIT) sponsors research and development (R & D) to improve the energy efficiency of American industry and to provide for fuel flexibility. Working closely with industry, OIT has successfully developed more than 50 new technologies that saved industry approximately 80 trillion Btu (84 quadrillion joules) of energy in 1992. More than 200 other projects are in various stages of development from laboratory research to field tests. The use of solvents in the industrial sector is widespread and results in the emission of volatile organic compounds (VOC's) to the atmosphere. These VOC emissions represent an economic loss to industry and contribute significantly to air pollution. To comply with increasingly strict environmental regulations while keeping costs down, industry must find efficient and cost-effective ways to control emissions from solvent use.

Differences Between Magnitudes and Health Impacts of BC ...

EPA Pesticide Factsheets

Recent assessments have analyzed the health impacts of PM2.5 from emissions from different locations and sectors using simplified or reduced-form air quality models. Here we present an alternative approach using the adjoint of the Community Multiscale Air Quality (CMAQ) model, which provides source–receptor relationships at highly resolved sectoral, spatial, and temporal scales. While damage resulting from anthropogenic emissions of BC is strongly correlated with population and premature death, we found little correlation between damage and emission magnitude, suggesting that controls on the largest emissions may not be the most efficient means of reducing damage resulting from anthropogenic BC emissions. Rather, the best proxy for locations with damaging BC emissions is locations where premature deaths occur. Onroad diesel and nonroad vehicle emissions are the largest contributors to premature deaths attributed to exposure to BC, while onroad gasoline emissions cause the highest deaths per amount emitted. Emissions in fall and winter contribute to more premature deaths (and more per amount emitted) than emissions in spring and summer. Overall, these results show the value of the high-resolution source attribution for determining the locations, seasons, and sectors for which BC emission controls have the most effective health benefits. The National Exposure Research Laboratory’s Atmospheric Modeling Division (AMAD) conducts research in support of EPA’s mis

40 CFR 63.3493 - What work practice standards must I meet?

Code of Federal Regulations, 2010 CFR

2010-07-01

... or the control efficiency/outlet concentration option to comply with the emission limitations, you... materials, and waste materials must be conveyed from one location to another in closed containers or pipes...

[Efficiency of industrial energy conservation and carbon emission reduction in Liaoning Pro-vince based on data envelopment analysis (DEA)method.

PubMed

Wang, Li; Xi, Feng Ming; Li, Jin Xin; Liu, Li Li

2016-09-01

Taking 39 industries as independent decision-making units in Liaoning Province from 2003 to 2012 and considering the benefits of energy, economy and environment, we combined direction distance function and radial DEA method to estimate and decompose the energy conservation and carbon emissions reduction efficiency of the industries. Carbon emission of each industry was calculated and defined as an undesirable output into the model of energy saving and carbon emission reduction efficiency. The results showed that energy saving and carbon emission reduction efficiency of industries had obvious heterogeneity in Liaoning Province. The whole energy conservation and carbon emissions reduction efficiency in each industry of Liaoning Province was not high, but it presented a rising trend. Improvements of pure technical efficiency and scale efficiency were the main measures to enhance energy saving and carbon emission reduction efficiency, especially scale efficiency improvement. In order to improve the energy saving and carbon emission reduction efficiency of each industry in Liaoning Province, we put forward that Liaoning Province should adjust industry structure, encourage the development of low carbon high benefit industries, improve scientific and technological level and adjust the industry scale reasonably, meanwhile, optimize energy structure, and develop renewable and clean energy.

Effects of the updated national emission regulation in China on circulating fluidized bed boilers and the solutions to meet them.

PubMed

Li, Jingji; Yang, Hairui; Wu, Yuxin; Lv, Junfu; Yue, Guangxi

2013-06-18

The advantage of circulating fluidized bed (CFB) boilers in China is their ability to utilize low rank coal with low cost emission control. However, the new National Emission Regulation (NER) issued in early 2012 brings much more stringent challenges on the CFB industries, which also causes much attention from other countries. Based on the principle of a CFB boiler and previous operating experience, it is possible for the CFB boilers to meet the new NER and maintain the advantage of low cost emission control, while, more influences should be considered in their design and operation. To meet the requirement of the new NER, the fly ash collector should adopt a bag house or combination of electrostatic precipitator and bag filter to ensure dust emissions of less than 30 mg · Nm(-3). For SO2 emission control, the bed temperature should be strictly lower than 900 °C to maintain high reactivity and pores. The limestone particle size distribution should be ranged within a special scope to optimize the residence time and gas-solid reaction. At the same time, the injecting point should be optimized to ensure fast contact of lime with oxygen. In such conditions, the desulfurization efficiency could be increased more than 90%. For lower sulfur content fuels (<1.5%, referred value based on the heating value of standard coal of China), increasing Ca/S enough could decrease SO2 emissions lower than that of the new NER, 100 mg · Nm(-3). For fuels with sulfur content higher than 1.5%, some simplified systems for flue gas desulfurization, such as flash dryer absorber (FDA), are needed. And the NOx emissions of a CFB can be controlled to less than 100 mg · Nm(-3) without any equipment at a bed temperature lower than 900 °C for fuels with low volatiles content (<12%), while for fuels with high volatiles, selective non-catalytic reduction (SNCR) should be considered. Due to the unique temperature in CFB as well as the circulating ash, the efficiency of SNCR could reach as high as 70%. The Hg emission of CFB is very low for the new NER due to its innate property.

Emission control system

NASA Technical Reports Server (NTRS)

Parrish, Clyde F. (Inventor); Chung, J. Landy (Inventor)

2009-01-01

Methods and apparatus utilizing hydrogen peroxide are useful to reduce SOx and mercury (or other heavy metal) emissions from combustion flue gas streams. The methods and apparatus may further be modified to reduce NOx emissions. Continuous concentration of hydrogen peroxide to levels approaching or exceeding propellant-grade hydrogen peroxide facilitates increased system efficiency. In this manner, combustion flue gas streams can be treated for the removal of SOx and heavy metals, while isolating useful by-products streams of sulfuric acid as well as solids for the recovery of the heavy metals. Where removal of NOx emissions is included, nitric acid may also be isolated for use in fertilizer or other industrial applications.

Beam impingement angle effects on secondary electron emission characteristics of textured pyrolytic graphite

NASA Technical Reports Server (NTRS)

Curren, A. N.; Jensen, K. A.

1984-01-01

Experimentally determined values of true secondary electron emission and relative values of reflected primary electron yield for untreated and ion-textured pyrolytic graphite over a range of primary electron energy levels and electron beam impingement angles are presented. Information required to develop high efficiency multistage depressed collectors (MDC's) for microwave amplifier traveling-wave tubes for space communication and aircraft applications is provided. To attain the highest possible MDC efficiencies, the electrode surfaces must have low secondary electron emission characteristics. Pyrolytic graphite, a chemically vapor-deposited material, is a particularly promising candidate for this application. The pyrolytic graphite surfaces studied were tested over a range of primary electron beam energies and beam impingement angles from 200 to 2000 eV and direct (0 deg) to near-grazing angles (85 deg), respectively. Surfaces both parallel to and normal to the planes of material deposition were examined. The true secondary electron emission and reflected primary electron yield characteristics of the pyrolytic graphite surfaces are compared to those of sooted control surfaces.

Reversed oxygen sensing using colloidal quantum wells towards highly emissive photoresponsive varnishes

PubMed Central

Lorenzon, Monica; Christodoulou, Sotirios; Vaccaro, Gianfranco; Pedrini, Jacopo; Meinardi, Francesco; Moreels, Iwan; Brovelli, Sergio

2015-01-01

Colloidal quantum wells combine the advantages of size-tunable electronic properties with vast reactive surfaces that could allow one to realize highly emissive luminescent-sensing varnishes capable of detecting chemical agents through their reversible emission response, with great potential impact on life sciences, environmental monitoring, defence and aerospace engineering. Here we combine spectroelectrochemical measurements and spectroscopic studies in a controlled atmosphere to demonstrate the ‘reversed oxygen-sensing’ capability of CdSe colloidal quantum wells, that is, the exposure to oxygen reversibly increases their luminescence efficiency. Spectroelectrochemical experiments allow us to directly relate the sensing response to the occupancy of surface states. Magneto-optical measurements demonstrate that, under vacuum, heterostructured CdSe/CdS colloidal quantum wells stabilize in their negative trion state. The high starting emission efficiency provides a possible means to enhance the oxygen sensitivity by partially de-passivating the particle surfaces, thereby enhancing the density of unsaturated sites with a minimal cost in term of luminescence losses. PMID:25910499

Evaluation of alternative landfill cover soils for attenuating hydrogen sulfide from construction and demolition (C&D) debris landfills.

PubMed

Plaza, Cristine; Xu, Qiyong; Townsend, Timothy; Bitton, Gabriel; Booth, Matthew

2007-08-01

Hydrogen sulfide (H(2)S) generated from C&D debris landfills has emerged as a major environmental concern due to odor problems and possible health impacts to landfill employees and surrounding residents. Research was performed to evaluate the performance of various cover materials as control measures for H(2)S emissions from C&D debris landfills. Twelve laboratory-scale simulated landfill columns containing gypsum drywall were operated under anaerobic conditions to promote H(2)S production. Five different cover materials were placed on top of the waste inside duplicate columns: (1) sandy soil, (2) sandy soil amended with lime, (3) clayey soil, (4) fine concrete (particle size less than 2.5 cm), and (5) coarse concrete (particle size greater than 2.5 cm). No cover was placed on two of the columns, which were used as controls. H(2)S concentrations measured from the middle of the waste layer ranged from 50,000 to 150,000 ppm. The different cover materials demonstrated varying H(2)S removal efficiencies. The sandy soil amended with lime and the fine concrete were the most effective for the control of H(2)S emissions. Both materials exhibited reduction efficiencies greater than 99%. The clayey and sandy soils exhibited lower reduction efficiencies, with average removal efficiencies of 65% and 30%, respectively. The coarse concrete was found to be the least efficient material as a result of its large particle size.

Odour in composting processes at pilot scale: monitoring and biofiltration.

PubMed

Gutiérrez, M C; Serrano, A; Martín, M A; Chica, A F

2014-08-01

Although odour emissions associated with the composting process, especially during the hydrolytic stage, are widely known, their impact on surrounding areas is not easily quantifiable, For this reason, odour emissions during the first stage ofcomposting were evaluated by dynamic olfactometry at pilot scale in order to obtain results which can be extrapolated to industrial facilities. The composting was carried out in a commercial dynamic respirometer equipped with two biofilters at pilot scale filled with prunings (Populus) and mature compost obtained from the organic fraction of municipal solid waste. Given that the highest odour emissions occur in the first stage of the composting process, this stage was carried out in a closed system to better control the odour emissions, whose maximum value was estimated to be 2.78 ouF S-1 during the experiments. Odour concentration, the dynamic respiration index and temperature showed the same evolution during composting, thus indicating that odour could be a key variable in the monitoring process. Other variables such as total organic carbon (CTOC) and pH were also found to be significant in this study due to their influence over odour emissions. The efficiency of the biofilters (empty bed residence time of 86 s) was determined by quantifying the odour emissions at the inlet and outlet of both biofilters. The moisture content in the biofilters was found to be an important variable for improving odour removal efficiency, while the minimum moisture percentage to obtain successful results was found to be 55% (odour removal efficiency of 95%).

Photoluminescence Spectra From The Direct Energy Gap of a-SiQDs

NASA Astrophysics Data System (ADS)

Abdul-Ameer, Nidhal M.; Abdulrida, Moafak C.; Abdul-Hakeem, Shatha M.

2018-05-01

A theoretical model for radiative recombination in amorphous silicon quantum dots (a-SiQDs) was developed. In this model, for the first time, the coexistence of both spatial and quantum confinements were considered. Also, it is found that the photoluminescence exhibits significant size dependence in the range (1-4) nm of the quantum dots. a-SiQDs show visible light emission peak energies and high radiative quantum efficiency at room temperature,in contrast to bulk a-Si structures. The quantum efficiency is sensitive to any change in defect density (the volume nonradiative centers density and/or the surface nonradiative centers density) but, with small dots sizes, the quantum efficiency is insensitive to such defects. Our analysis shows that the photoluminescence intensity increases or decreases by the effect of radiative quantum efficiency. By controlling the size of a-SiQDs, we note that the energy of emission can be tuned. The blue shift is attributed to quantum confinement effect. Meanwhile, the spatial confinement effect is clearly observed in red shift in emission spectra. we found a good agreement with the experimental published data. Therefore, we assert that a-SiQDs material is a promising candidate for visible, tunable, and high performance devices of light emitting.

Improving fumigation efficiency by increasing drip-tape number and using low permeability film in raised-bed production systems

USDA-ARS?s Scientific Manuscript database

Drip fumigation is commonly used for controlling soilborne pests in raised-bed strawberry production systems in California. However, the high emission loss and poor pest control indicate that the current fumigation practice with two drip tapes and polyethylene film (PE) covering need to be improved....

Environmental assessment of combustion modification controls for stationary internal combustion engines. Final report Sep 78-Jul 79

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lips, H.I.; Gotterba, J.A.; Lim, K.J.

1981-07-01

The report gives results of an environmental assessment of combustion modification techniques for stationary internal combustion engines, with respect to NOx control reduction effectiveness, operational impact, thermal efficiency impact, capital and annualized operating costs, and effects on emissions of pollutants other than NOx.

Impacts of continuously regenerating trap and particle oxidation catalyst on the NO2 and particulate matter emissions emitted from diesel engine.

PubMed

Liu, Zhihua; Ge, Yunshan; Tan, Jianwei; He, Chao; Shah, Asad Naeem; Ding, Yan; Yu, Linxiao; Zhao, Wei

2012-01-01

Two continuously regenerating diesel particulate filter (CRDPF) with different configurations and one particles oxidation catalyst (POC) were employed to perform experiments in a controlled laboratory setting to evaluate their effects on NO2, smoke and particle number emissions. The results showed that the application of the after-treatments increased the emission ratios of NO2/NOx significantly. The results of smoke emissions and particle number (PN) emissions indicated that both CRDPFs had sufficient capacity to remove more than 90% of total particulate matter (PM) and more than 97% of solid particles. However, the POC was able to remove the organic components of total PM, and only partially to remove the carbonaceous particles with size less than 30 nm. The negligible effects of POC on larger particles were observed due to its honeycomb structure leads to an inadequate residence time to oxidize the solid particles or trap them. The particles removal efficiencies of CRDPFs had high degree of correlations with the emission ratio of NO2/NOx. The PN emission results from two CRDPFs indicated that more NO2 generating in diesel oxidation catalyst section could obtain the higher removal efficiency of solid particles. However this also increased the risk of NO2 exposure in atmosphere.

Advanced Collaborative Emissions Study (ACES)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Greenbaum, Daniel; Costantini, Maria; Van Erp, Annemoon

2013-12-31

The objective of the Advanced Collaborative Emissions Study (ACES) was to determine before widespread commercial deployment whether or not the new, energy-efficient, heavy duty diesel engines (2007 and 2010 EPA Emissions Standards Compliant) may generate anticipated toxic emissions that could adversely affect the environment and human health. ACES was planned to take place in three phases. In Phase 1, extensive emissions characterization of four production-intent prototype engine and control systems designed to meet 2007 standards for nitrogen oxides (NOx) and particulate matter (PM) was conducted at an existing emissions characterization facility: Southwest Research Institute (SwRI). One of the tested enginesmore » was selected (at random, after careful comparison of results) for health testing in Phase 3. In Phase 2, extensive emission characterization of three production-intent prototype engine and control systems meeting the 2010 standards (including more advanced NOx controls to meet the more stringent 2010 NOx standards) was conducted at the same test facility. In Phase 3, one engine/aftertreatment system selected from Phase 1 was further characterized during health effects studies (at an existing inhalation toxicology laboratory: Lovelace Respiratory Research Institute, [LRRI]) to form the basis of the ACES safety assessment. The Department of Energy (DOE) award provided funding for emissions characterization in Phases 1 and 2 as well as exposure characterization in Phase 3. The main health analyses in Phase 3 were funded separately and are not reported here.« less

Impact of Uncertainty from Load-Based Reserves and Renewables on Dispatch Costs and Emissions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Bowen; Maroukis, Spencer D.; Lin, Yashen

2016-11-21

Aggregations of controllable loads are considered to be a fast-responding, cost-efficient, and environmental-friendly candidate for power system ancillary services. Unlike conventional service providers, the potential capacity from the aggregation is highly affected by factors like ambient conditions and load usage patterns. Previous work modeled aggregations of controllable loads (such as air conditioners) as thermal batteries, which are capable of providing reserves but with uncertain capacity. A stochastic optimal power flow problem was formulated to manage this uncertainty, as well as uncertainty in renewable generation. In this paper, we explore how the types and levels of uncertainty, generation reserve costs, andmore » controllable load capacity affect the dispatch solution, operational costs, and CO2 emissions. We also compare the results of two methods for solving the stochastic optimization problem, namely the probabilistically robust method and analytical reformulation assuming Gaussian distributions. Case studies are conducted on a modified IEEE 9-bus system with renewables, controllable loads, and congestion. We find that different types and levels of uncertainty have significant impacts on dispatch and emissions. More controllable loads and less conservative solution methodologies lead to lower costs and emissions.« less

Development of Diesel Exhaust Aftertreatment System for Tier II Emissions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, R. C.; Cole, A. S., Stroia, B. J.; Huang, S. C.

2002-06-01

Due to their excellent fuel efficiency, reliability, and durability, compression ignition direct injection (CIDI) engines have been used extensively to power almost all highway trucks, urban buses, off-road vehicles, marine carriers, and industrial equipment. CIDI engines burn 35 to 50% less fuel than gasoline engines of comparable size, and they emit far less greenhouse gases (Carbon Dioxides), which have been implicated in global warming. Although the emissions of CIDI engines have been reduced significantly over the last decade, there remains concern with the Nitrogen Oxides (NOX) and Particulate Matter (PM) emission levels. In 2000, the US EPA proposed very stringentmore » emissions standards to be introduced in 2007 along with low sulfur (< 15ppm) diesel fuel. The California Air Resource Board (CARB) has also established the principle that future diesel fueled vehicles should meet the same emissions standards as gasoline fueled vehicles and the EPA followed suit with its Tier II emissions regulations. Meeting the Tier II standards requires NOX and PM emissions to be reduced dramatically. Achieving such low emissions while minimizing fuel economy penalty cannot be done through engine development and fuel reformulation alone, and requires application of NOX and PM aftertreatment control devices. A joint effort was made between Cummins Inc. and the Department of Energy to develop the generic aftertreatment subsystem technologies applicable for Light-Duty Vehicle (LDV) and Light-Duty Truck (LDT) engines. This paper provides an update on the progress of this joint development program. Three NOX reduction technologies including plasmaassisted catalytic NOX reduction (PACR), active lean NOX catalyst (LNC), and adsorber catalyst (AC) technology using intermittent rich conditions for NOX reduction were investigated in parallel in an attempt to select the best NOX control approach for light-duty aftertreatment subsystem integration and development. Investigations included system design and analysis, critical lab/engine experiments, and ranking then selection of NOX control technologies against reliability, up-front cost, fuel economy, service interval/serviceability, and size/weight. The results of the investigations indicate that the best NOX control approach for LDV and LDT applications is a NOX adsorber system. A greater than 83% NOX reduction efficiency is required to achieve 0.07g/mile NOX Tier II vehicle-out emissions. Both active lean NOX and PACR technology are currently not capable of achieving the high conversion efficiency required for Tier II, Bin 5 emissions standards. In this paper, the NOX technology assessment and selection is first reviewed and discussed. Development of the selected NOX technology (NOX adsorber) and PM control are then discussed in more detail. Discussion includes exhaust sulfur management, further adsorber formulation development, reductant screening, diesel particulate filter development & active regeneration, and preliminary test results on the selected integrated SOX trap, NOX adsorber, and diesel particulate filter system over an FTP-75 emissions cycle, and its impact on fuel economy. Finally, the direction of future work for continued advanced aftertreatment technology development is discussed. (SAE Paper SAE-2002-01-1867 © 2002 SAE International. This paper is published on this website with permission from SAE International. As a user of this website, you are permitted to view this paper on-line, download this pdf file and print one copy of this paper at no cost for your use only. The downloaded pdf file and printout of this SAE paper may not be copied, distributed or forwarded to others or for the use of others.)« less

Connected Vehicle Technologies for Efficient Urban Transportation

DOT National Transportation Integrated Search

2016-10-24

Connected vehicle technology is employed to optimize the vehicle's control system in real-time to reduce congestion, improve fuel economy, and reduce emissions. This project's goal was to develop a two-way communication system to upload vehicle data ...

Impacts of the Minamata Convention for Mercury Emissions from Coal-fired Power Generation in Asia

NASA Astrophysics Data System (ADS)

Giang, A.; Stokes, L. C.; Streets, D. G.; Corbitt, E. S.; Selin, N. E.

2014-12-01

We explore the potential implications of the recently signed United Nations Minamata Convention on Mercury for emissions from coal-fired power generation in Asia, and the impacts of these emissions changes on deposition of mercury worldwide by 2050. We use qualitative interviews, document analysis, and engineering analysis to create plausible technology scenarios consistent with the Convention, taking into account both technological and political factors. We translate these scenarios into possible emissions inventories for 2050, based on IPCC development scenarios, and then use the GEOS-Chem global transport model to evaluate the effect of these different technology choices on mercury deposition over geographic regions and oceans. We find that China is most likely to address mercury control through co-benefits from technologies for SO2, NOx, and particulate matter (PM) capture that will be required to attain its existing air quality goals. In contrast, India is likely to focus on improvements to plant efficiency such as upgrading boilers, and coal washing. Compared to current technologies, we project that these changes will result in emissions decreases of approximately 140 and 190 Mg/yr for China and India respectively in 2050, under an A1B development scenario. With these emissions reductions, simulated average gross deposition over India and China are reduced by approximately 10 and 3 μg/m2/yr respectively, and the global average concentration of total gaseous mercury (TGM) is reduced by approximately 10% in the Northern hemisphere. Stricter, but technologically feasible, requirements for mercury control in both countries could lead to an additional 200 Mg/yr of emissions reductions. Modeled differences in concentration and deposition patterns between technology suites are due to differences in both the mercury removal efficiency of technologies and their resulting stack speciation.

Tunneling-injection in vertical quasi-2D heterojunctions enabled efficient and adjustable optoelectronic conversion

PubMed Central

Tan, Wei-Chun; Chiang, Chia-Wei; Hofmann, Mario; Chen, Yang-Fang

2016-01-01

The advent of 2D materials integration has enabled novel heterojunctions where carrier transport proceeds thrsough different ultrathin layers. We here demonstrate the potential of such heterojunctions on a graphene/dielectric/semiconductor vertical stack that combines several enabling features for optoelectronic devices. Efficient and stable light emission was achieved through carrier tunneling from the graphene injector into prominent states of a luminescent material. Graphene’s unique properties enable fine control of the band alignment in the heterojunction. This advantage was used to produce vertical tunneling-injection light-emitting transistors (VtiLET) where gating allows adjustment of the light emission intensity independent of applied bias. This device was shown to simultaneously act as a light detecting transistor with a linear and gate tunable sensitivity. The presented development of an electronically controllable multifunctional light emitter, light detector and transistor open up a new route for future optoelectronics. PMID:27507171

Tunneling-injection in vertical quasi-2D heterojunctions enabled efficient and adjustable optoelectronic conversion

NASA Astrophysics Data System (ADS)

Tan, Wei-Chun; Chiang, Chia-Wei; Hofmann, Mario; Chen, Yang-Fang

2016-08-01

The advent of 2D materials integration has enabled novel heterojunctions where carrier transport proceeds thrsough different ultrathin layers. We here demonstrate the potential of such heterojunctions on a graphene/dielectric/semiconductor vertical stack that combines several enabling features for optoelectronic devices. Efficient and stable light emission was achieved through carrier tunneling from the graphene injector into prominent states of a luminescent material. Graphene’s unique properties enable fine control of the band alignment in the heterojunction. This advantage was used to produce vertical tunneling-injection light-emitting transistors (VtiLET) where gating allows adjustment of the light emission intensity independent of applied bias. This device was shown to simultaneously act as a light detecting transistor with a linear and gate tunable sensitivity. The presented development of an electronically controllable multifunctional light emitter, light detector and transistor open up a new route for future optoelectronics.

Thermal Emission Control via Bandgap Engineering in Aperiodically Designed Nanophotonic Devices.

PubMed

Maciá, Enrique

2015-05-20

Aperiodic photonic crystals can open up novel routes for more efficient photon management due to increased degrees of freedom in their design along with the unique properties brought about by the long-range aperiodic order as compared to their periodic counterparts. In this work we first describe the fundamental notions underlying the idea of thermal emission/absorption control on the basis of the systematic use of aperiodic multilayer designs in photonic quasicrystals. Then, we illustrate the potential applications of this approach in order to enhance the performance of daytime radiative coolers and solar thermoelectric energy generators.

Thermal Emission Control via Bandgap Engineering in Aperiodically Designed Nanophotonic Devices

PubMed Central

Maciá, Enrique

2015-01-01

Aperiodic photonic crystals can open up novel routes for more efficient photon management due to increased degrees of freedom in their design along with the unique properties brought about by the long-range aperiodic order as compared to their periodic counterparts. In this work we first describe the fundamental notions underlying the idea of thermal emission/absorption control on the basis of the systematic use of aperiodic multilayer designs in photonic quasicrystals. Then, we illustrate the potential applications of this approach in order to enhance the performance of daytime radiative coolers and solar thermoelectric energy generators. PMID:28347037

Infrared Radiation Filament And Metnod Of Manufacture

DOEpatents

Johnson, Edward A.

1998-11-17

An improved IR radiation source is provided by the invention. A radiation filament has a textured surface produced by seeded ion bombardment of a metal foil which is cut to a serpentine shape and mounted in a windowed housing. Specific ion bombardment texturing techniques tune the surface to maximize emissions in the desired wavelength range and to limit emissions outside that narrow range, particularly at longer wavelengths. A combination of filament surface texture, thickness, material, shape and power circuit feedback control produce wavelength controlled and efficient radiation at much lower power requirements than devices of the prior art.

Automated Boiler Combustion Controls for Emission Reduction and Efficiency Improvement

DOE Office of Scientific and Technical Information (OSTI.GOV)

None, None

1998-12-02

In the late 1980s, then President Bush visited Krakow, Poland. The terrible air quality theremotivated him to initiate a USAID-funded program, managed by DOE, entitled "Krakow Clean Fossil Fuels and Energy Efficiency Program." The primary objective of this program was to encourage the formation of commercial ventures between U.S. and Polish firms to provide equipment and/or services to reduce pollution from low-emission sources in Krakow, Poland. This program led to the award of a number of cooperative agreements, including one to Control Techtronics International. The technical objective of CTI's cooperative agreement is to apply combustion controls to existing boiler plantsmore » in Krakow and transfer knowledge and technology through a joint U.S. and Polish commercial venture. CTI installed automatic combustion controls on five coal boilers for the district heating system in Krakow. Three of these were for domestic hot-water boilers, and two were for steam for industrial boilers. The following results have occurred due to the addition of CTI's combustion controls on these five existing boilers: ! 25% energy savings ! 85% reduction in particulate emissions The joint venture company CTI-Polska was then established. Eleven additional technical and costing proposals were initiated to upgrade other coal boilers in Krakow. To date, no co-financing has been made available on the Polish side. CTI-Polska continues in operation, serving customers in Russia and Ukraine. Should the market in Poland materialize, the joint venture company is established there to provide equipment and service.« less

Compact, closed-loop controlled waste incinerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schadow, K.C.; Seeker, W.R.

1999-07-01

Technologies for solid and liquid waste destruction in compact incinerators are being developed in collaboration between industry, universities, and a Government laboratory. This paper reviews progress on one technology, namely active combustion control to achieve efficient and controlled afterburning of air-starved reaction products. This technology which uses synchronized waste gas injection into acoustically stabilized air vortices was transitioned to a simplified afterburner design and practical operational conditions. The full-scale, simplified afterburner, which achieved CO and NO{sub x} emissions of about 30 ppm with a residence time of less than 50 msec, was integrated with a commercially available marine incinerator tomore » increase throughput and reduce emissions. Closed-loop active control with diode laser sensors and novel control strategies was demonstrated on a sub-scale afterburner.« less

Tunable long persistent luminescence in the second near-infrared window via crystal field control.

PubMed

Nie, Jianmin; Li, Yang; Liu, Shanshan; Chen, Qiuqun; Xu, Qi; Qiu, Jianrong

2017-09-29

Construction of an active composite as a biomarker with deeper tissue penetration and higher signal-to-noise ratio (SNR) is of great importance for the application in bioimaging. Here, we report a strategy for tuning the emission bandwidth and intensity via crystal field control in long persistent phosphors (LPPs). Ni 2+ -doped Zn 1+y Sn y Ga 2-x-2y O 4 phosphors, with a tunable emission band peaking from 1270 to 1430 nm in the second near-infrared (NIR) window, have been successfully prepared. Such featured materials have the advantages of low absorption and scattering as well as more efficient tissue penetration. The emission spectra can be controlled by tailoring the local crystal field around the activator precisely via substitution of Zn and Sn for Ga. Moreover, with high resolution and weak light disturbance, these developed multi-band afterglow phosphors exhibit great application potential in advanced optical imaging.

Long-Term Temporal Trends of Polychlorinated Biphenyls and Their Controlling Sources in China.

PubMed

Zhao, Shizhen; Breivik, Knut; Liu, Guorui; Zheng, Minghui; Jones, Kevin C; Sweetman, Andrew J

2017-03-07

Polychlorinated biphenyls (PCBs) are industrial organic contaminants identified as persistent, bioaccumulative, toxic (PBT), and subject to long-range transport (LRT) with global scale significance. This study focuses on a reconstruction and prediction for China of long-term emission trends of intentionally and unintentionally produced (UP) ∑ 7 PCBs (UP-PCBs, from the manufacture of steel, cement and sinter iron) and their re-emissions from secondary sources (e.g., soils and vegetation) using a dynamic fate model (BETR-Global). Contemporary emission estimates combined with predictions from the multimedia fate model suggest that primary sources still dominate, although unintentional sources are predicted to become a main contributor from 2035 for PCB-28. Imported e-waste is predicted to play an increasing role until 2020-2030 on a national scale due to the decline of intentionally produced (IP) emissions. Hypothetical emission scenarios suggest that China could become a potential source to neighboring regions with a net output of ∼0.4 t year -1 by around 2050. However, future emission scenarios and hence model results will be dictated by the efficiency of control measures.

Substantial Air Quality and Climate Co-benefits Achievable Now with Industrial Efficiency Improvements in China

NASA Astrophysics Data System (ADS)

Mauzerall, D. L.; Peng, W.; Wagner, F.; Yang, J.

2016-12-01

China is the world's top carbon emitter and suffers from severe air pollution. It has recently made commitments to improve air quality and peak its carbon emissions by 2030. Here we examine near-term air quality and implications for CO2 emissions of various sector-based policies in China that are widely discussed and technically plausible for immediate implementation. For each sector, we consider the effect of a 20% increase in the installation rate of available air pollution control devices, along with the following sector-specific policies. Power sector (POW): 80% replacement of small coal power plants with larger more efficient ones; Industry sector (IND): 20% improvement in energy efficiency; Transport sector (TRA): replacement of high emitters with average vehicle fleet emissions; and Residential sector (RES): replacement of 20% of coal-based stoves with those using liquefied petroleum gas. We conduct an integrated assessment using the air pollution model WRF-Chem and epidemiological concentration-response relationships to evaluate a 2015 base case and various counterfactual scenarios. We find that the IND scenario would reduce both the total national air-pollution-related deaths and carbon emissions the most of the four sectorial scenarios examined. Benefits of addressing the industrial sector remain large even when efficiency improvements are smaller than 20%. Moreover, we find that simultaneously implementing all the measures in all four sectors (combined, COMB) leads to slightly larger air quality and health benefits than obtained by summing the benefits achieved from the four sectorial scenarios individually. This is because nonlinearity in atmospheric chemistry leads to a larger reduction in fine particulate concentrations when emissions from all sectors are reduced simultaneously. The resulting lower concentrations imply a lower position on the concave human premature mortality relative risk curve with fewer associated deaths. While much effort has focused on reducing emissions from the power and transportation sectors, our analysis highlights the importance of efficiency improvements in the industrial sector as a mechanism to simultaneously improve air quality and public health while reducing CO2 emissions.

High Efficiency - Reduced Emissions Boiler Systems for Steam, Heat, and Processing

DTIC Science & Technology

2012-07-01

enable energy saving necessary for obtaining Energy Star certification for the whole boiler system. Widespread boiler control updates could be possible...adaptability to different boiler and oil/gas burner configurations, and extensibility to operation with nonconventional fuels (e.g., biogas and syngas...typically operating below or slightly above 80%. Higher efficiency improvements can certainly be obtained via boiler replacement and adoption of

Broadband infrared light emitting waveguides based on UV curable PbS quantum dot composites

NASA Astrophysics Data System (ADS)

Shen, Kai; Baig, Sarfaraz; Jiang, Guomin; Paik, Young-hun; Kim, Sung Jin; Wang, Michael R.

2018-02-01

We present herein the active PbS-photopolymer waveguide fabricated by vacuum assisted microfluidic (VAM) soft lithography technique. The PbS Quantum Dots (QDs) were synthesized using colloidal chemistry methods with tunable sizes and emission wavelengths, resulting in efficient light emission around 1000 nm center wavelength. The PbS QDs have demonstrated much better solubility in our newly synthesized UV curable polymer than SU-8 photoresist, verified by Photoluminescence (PL) testing. Through refractive index control, the PbS QDs-polymer core material and polymer cladding material can efficiently confine the infrared emitting light with a broad spectral bandwidth of 180 nm. Both single-mode and multi-mode light emitting waveguides have been realized.

Polarized and asymmetric emission of single colloidal nanoplatelets (Conference Presentation)

NASA Astrophysics Data System (ADS)

Feng, Fu; N'Guyen, Thu Loan; Nasilowski, Michel; Lethiec, Clotilde M.; Dubertret, Benoit; Coolen, Laurent; Maître, Agnès.

2017-02-01

Efficient coupling of nanoemitters to photonic or plasmonic structures requires the control of the orientation of the emitting dipoles. Nevertheless controlling the dipole orientation remains an experimental challenge. Many experiments rely on the realization of numerous samples, in order to be able to statistically get a well aligned dipole to realize an efficient coupling to a nanostructure. In order to avoid these statistical trials, the knowledge of the nature of the emitter and its orientation is crucial for a deterministical approach. We developed a method [1],[2] relying on the combination of polarimetric measurement and emission diagram which gives fine information both on the emitting dipolar transition involved and on the dipolar orientation We analyse by this method square and rectangle single colloidal CdSe/CdS nanoplatetelets. We demonstrate that their emission can be described by just by two orthogonal dipoles lying in the plane of the platelets. More surprisingly the emission of the square nanoplatelets is not polarised whereas the rectangle one is. We demonstrate that this polarized emission is due to the rectangular shape anisotropy by a dielectric effect. [1] C. Lethiec, et al, Three-dimensional orientation measurement of a single fluorescent nanoemitter by polarization analysis, Phys. Rev. X 4, 021037 (2014), [2] C. Lethiec et al, Polarimetry-based analysis of dipolar transitions of single colloidal CdSe/CdS dot-inrods, New Journal of Physics 16, 093014 (2014) [3] S. Ithurria et al, colloidal nanoplatelets with 2 dimensional electronic structure, Nature Materials 10, 936 (2011)

Genetic mitigation strategies to tackle agricultural GHG emissions: The case for biological nitrification inhibition technology.

PubMed

Subbarao, G V; Arango, J; Masahiro, K; Hooper, A M; Yoshihashi, T; Ando, Y; Nakahara, K; Deshpande, S; Ortiz-Monasterio, I; Ishitani, M; Peters, M; Chirinda, N; Wollenberg, L; Lata, J C; Gerard, B; Tobita, S; Rao, I M; Braun, H J; Kommerell, V; Tohme, J; Iwanaga, M

2017-09-01

Accelerated soil-nitrifier activity and rapid nitrification are the cause of declining nitrogen-use efficiency (NUE) and enhanced nitrous oxide (N 2 O) emissions from farming. Biological nitrification inhibition (BNI) is the ability of certain plant roots to suppress soil-nitrifier activity, through production and release of nitrification inhibitors. The power of phytochemicals with BNI-function needs to be harnessed to control soil-nitrifier activity and improve nitrogen-cycling in agricultural systems. Transformative biological technologies designed for genetic mitigation are needed, so that BNI-enabled crop-livestock and cropping systems can rein in soil-nitrifier activity, to help reduce greenhouse gas (GHG) emissions and globally make farming nitrogen efficient and less harmful to environment. This will reinforce the adaptation or mitigation impact of other climate-smart agriculture technologies. Copyright © 2017 Elsevier B.V. All rights reserved.

Co-Optimization of Internal Combustion Engines and Biofuels

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCormick, Robert L.

2016-03-08

The development of advanced engines has significant potential advantages in reduced aftertreatment costs for air pollutant emission control, and just as importantly for efficiency improvements and associated greenhouse gas emission reductions. There are significant opportunities to leverage fuel properties to create more optimal engine designs for both advanced spark-ignition and compression-ignition combustion strategies. The fact that biofuel blendstocks offer a potentially low-carbon approach to fuel production, leads to the idea of optimizing the entire fuel production-utilization value chain as a system from the standpoint of life cycle greenhouse gas emissions. This is a difficult challenge that has yet to bemore » realized. This presentation will discuss the relationship between chemical structure and critical fuel properties for more efficient combustion, survey the properties of a range of biofuels that may be produced in the future, and describe the ongoing challenges of fuel-engine co-optimization.« less

Design of wide-angle solar-selective absorbers using aperiodic metal-dielectric stacks.

PubMed

Sergeant, Nicholas P; Pincon, Olivier; Agrawal, Mukul; Peumans, Peter

2009-12-07

Spectral control of the emissivity of surfaces is essential in applications such as solar thermal and thermophotovoltaic energy conversion in order to achieve the highest conversion efficiencies possible. We investigated the spectral performance of planar aperiodic metal-dielectric multilayer coatings for these applications. The response of the coatings was optimized for a target operational temperature using needle-optimization based on a transfer matrix approach. Excellent spectral selectivity was achieved over a wide angular range. These aperiodic metal-dielectric stacks have the potential to significantly increase the efficiency of thermophotovoltaic and solar thermal conversion systems. Optimal coatings for concentrated solar thermal conversion were modeled to have a thermal emissivity <7% at 720K while absorbing >94% of the incident light. In addition, optimized coatings for solar thermophotovoltaic applications were modeled to have thermal emissivity <16% at 1750K while absorbing >85% of the concentrated solar radiation.

Cascaded Emission Regions in 2.4 μm GaInAsSb Light Emitting Diode's for Improved Current Efficiency

NASA Astrophysics Data System (ADS)

Prineas, John; Yager, Jeff; Olesberg, Jonathon; Cao, Chuanshun; Reddy, Madhu; Coretsopoulos, Chris

2008-03-01

Infrared optoelectronics play an important role in sensing of molecules through characteristic vibrational resonances that occur at those wavelengths. For molecules in aqueous and at room temperature, where optical transistions tend to be broad, the broadband emission of light emitting diodes (LEDs) are well suited for obtaining molecular absorption spectra. The 2-2.6 μm range is an advantageous range for sensing of glucose. Voltages available in batteries and control electronics are limited to much higher voltages than those required to turn on an infrared LED, and moreover have limited current supply. Here, we demonstrate room temperature operature of 5-stage cascaded emission regions in 2-2.6 μm GaInAsSb LEDs. We report three times higher turn on voltage, and nine times improved current efficiency compared to a single stage device.

Mitigation of severe urban haze pollution by a precision air pollution control approach.

PubMed

Yu, Shaocai; Li, Pengfei; Wang, Liqiang; Wu, Yujie; Wang, Si; Liu, Kai; Zhu, Tong; Zhang, Yuanhang; Hu, Min; Zeng, Liming; Zhang, Xiaoye; Cao, Junji; Alapaty, Kiran; Wong, David C; Pleim, Jon; Mathur, Rohit; Rosenfeld, Daniel; Seinfeld, John H

2018-05-25

Severe and persistent haze pollution involving fine particulate matter (PM 2.5 ) concentrations reaching unprecedentedly high levels across many cities in China poses a serious threat to human health. Although mandatory temporary cessation of most urban and surrounding emission sources is an effective, but costly, short-term measure to abate air pollution, development of long-term crisis response measures remains a challenge, especially for curbing severe urban haze events on a regular basis. Here we introduce and evaluate a novel precision air pollution control approach (PAPCA) to mitigate severe urban haze events. The approach involves combining predictions of high PM 2.5 concentrations, with a hybrid trajectory-receptor model and a comprehensive 3-D atmospheric model, to pinpoint the origins of emissions leading to such events and to optimize emission controls. Results of the PAPCA application to five severe haze episodes in major urban areas in China suggest that this strategy has the potential to significantly mitigate severe urban haze by decreasing PM 2.5 peak concentrations by more than 60% from above 300 μg m -3 to below 100 μg m -3 , while requiring ~30% to 70% less emission controls as compared to complete emission reductions. The PAPCA strategy has the potential to tackle effectively severe urban haze pollution events with economic efficiency.

Replacing Gasoline : Alternative Fuels for Light-Duty Vehicles

DOT National Transportation Integrated Search

1990-09-01

Among the several major issues that Congress addressed in the process of reauthorizing the Clean Air Act was the future role of alternative highway transportation fuels in reducing urban smog. As vehicular emissions control efficiencies rose past 90 ...

Characteristics of inhalable particulate matter concentration and size distribution from power plants in China.

PubMed

Yi, Honghong; Hao, Jiming; Duan, Lei; Li, Xinghua; Guo, Xingming

2006-09-01

In this investigation, the collection efficiency of particulate emission control devices (PECDs), particulate matter (PM) emissions, and PM size distribution were determined experimentally at the inlet and outlet of PECDs at five coal-fired power plants. Different boilers, coals, and PECDs are used in these power plants. Measurement in situ was performed by an electrical low-pressure impactor with a sampling system, which consisted of an isokinetic sampler probe, precut cyclone, and two-stage dilution system with a sample line to the instruments. The size distribution was measured over a range from 0.03 to 10 microm. Before and after all of the PECDs, the particle number size distributions display a bimodal distribution. The PM2.5 fraction emitted to atmosphere includes a significant amount of the mass from the coarse particle mode. The controlled and uncontrolled emission factors of total PM, inhalable PM (PM10), and fine PM P(M2.5) were obtained. Electrostatic precipitator (ESP) and baghouse total collection efficiencies are 96.38-99.89% and 99.94%, respectively. The minimum collection efficiency of the ESP and the baghouse both appear in the particle size range of 0.1-1 microm. In this size range, ESP and baghouse collection efficiencies are 85.79-98.6% and 99.54%. Real-time measurement shows that the mass and number concentration of PM10 will be greatly affected by the operating conditions of the PECDs. The number of emitted particles increases with increasing boiler load level because of higher combustion temperature. During test run periods, the data reproducibility is satisfactory.

[Measurement model of carbon emission from forest fire: a review].

PubMed

Hu, Hai-Qing; Wei, Shu-Jing; Jin, Sen; Sun, Long

2012-05-01

Forest fire is the main disturbance factor for forest ecosystem, and an important pathway of the decrease of vegetation- and soil carbon storage. Large amount of carbonaceous gases in forest fire can release into atmosphere, giving remarkable impacts on the atmospheric carbon balance and global climate change. To scientifically and effectively measure the carbonaceous gases emission from forest fire is of importance in understanding the significance of forest fire in the carbon balance and climate change. This paper reviewed the research progress in the measurement model of carbon emission from forest fire, which covered three critical issues, i. e., measurement methods of forest fire-induced total carbon emission and carbonaceous gases emission, affecting factors and measurement parameters of measurement model, and cause analysis of the uncertainty in the measurement of the carbon emissions. Three path selections to improve the quantitative measurement of the carbon emissions were proposed, i. e., using high resolution remote sensing data and improving algorithm and estimation accuracy of burned area in combining with effective fuel measurement model to improve the accuracy of the estimated fuel load, using high resolution remote sensing images combined with indoor controlled environment experiments, field measurements, and field ground surveys to determine the combustion efficiency, and combining indoor controlled environment experiments with field air sampling to determine the emission factors and emission ratio.

Nitrogen oxides emissions from thermal power plants in china: current status and future predictions.

PubMed

Tian, Hezhong; Liu, Kaiyun; Hao, Jiming; Wang, Yan; Gao, Jiajia; Qiu, Peipei; Zhu, Chuanyong

2013-10-01

Increasing emissions of nitrogen oxides (NOx) over the Chinese mainland have been of great concern due to their adverse impacts on regional air quality and public health. To explore and obtain the temporal and spatial characteristics of NOx emissions from thermal power plants in China, a unit-based method is developed. The method assesses NOx emissions based on detailed information on unit capacity, boiler and burner patterns, feed fuel types, emission control technologies, and geographical locations. The national total NOx emissions in 2010 are estimated at 7801.6 kt, of which 5495.8 kt is released from coal-fired power plant units of considerable size between 300 and 1000 MW. The top provincial emitter is Shandong where plants are densely concentrated. The average NOx-intensity is estimated at 2.28 g/kWh, markedly higher than that of developed countries, mainly owing to the inadequate application of high-efficiency denitrification devices such as selective catalytic reduction (SCR). Future NOx emissions are predicted by applying scenario analysis, indicating that a reduction of about 40% by the year 2020 can be achieved compared with emissions in 2010. These results suggest that NOx emissions from Chinese thermal power plants could be substantially mitigated within 10 years if reasonable control measures were implemented effectively.

Biofiltration: An innovative air pollution control technology for VOC emissions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leson, G.; Winer, A.M.

1991-08-01

Biofiltration is a relatively recent air pollution control (APC) technology in which off-gases containing biodegradable volatile organic compounds (VOC) or inorganic air toxics are vented through a biologically active material. This technology has been successfully applied in Germany and The Netherlands in many full-scale applications to control odors, VOC and air toxic emissions from a wide range of industrial and public sector sources. Control efficiencies of more than 90 percent have been achieved for many common air pollutants. Due to lower operating costs, biofiltration can provide significant economic advantages over other APC technologies if applied to off-gases that contain readilymore » biodegradable pollutants in low concentrations. Environmental benefits include low energy requirements and the avoidance of cross media transfer of pollutants. This paper reviews the history and current status of biofiltration, outlines its underlying scientific and engineering principles, and discusses the applicability of biofilters for a wide range of specific emission sources.« less

Bluish-White Luminescence in Rare-Earth-Free Vanadate Garnet Phosphors: Structural Characterization of LiCa3MV3O12 (M = Zn and Mg).

PubMed

Hasegawa, Takuya; Abe, Yusuke; Koizumi, Atsuya; Ueda, Tadaharu; Toda, Kenji; Sato, Mineo

2018-01-16

Extensive attention has been focused toward studies on inexpensive and rare-earth-free garnet-structure vanadate phosphors, which do not have a low optical absorption due to the luminescence color being easily controlled by its high composition flexibility. However, bluish emission phosphors with a high quantum efficiency have not been found until now. In this study, we successfully discovered bluish-white emitting, garnet structure-based LiCa 3 MV 3 O 12 (M = Zn and Mg) phosphors with a high quantum efficiency, and the detailed crystal structure was refined by the Rietveld analysis technique. These phosphors exhibit a broad-band emission spectra peak at 481 nm under near UV-light excitation at 341 nm, indicating no clear difference in the emission and excitation spectra. A very compact tetrahedral [VO 4 ] unit is observed in the LiCa 3 MV 3 O 12 (M = Zn and Mg) phosphors, which is not seen in other conventional garnet compounds, and generates a bluish-white emission. In addition, these phosphors exhibit high quantum efficiencies of 40.1% (M = Zn) and 44.0% (M = Mg), respectively. Therefore, these vanadate garnet phosphors can provide a new blue color source for LED devices.

Efficiency of an emissions payment system for nitrogen in sewage treatment plants - a case study.

PubMed

Malmaeus, J Mikael; Ek, Mats; Åmand, Linda; Roth, Susanna; Baresel, Christian; Olshammar, Mikael

2015-05-01

An emissions payment system for nitrogen in Swedish sewage treatment plants (STPs) was evaluated using a semi-empirical approach. The system was based on a tariff levied on each unit of nitrogen emitted by STPs, and profitable measures to reduce nitrogen emissions were identified for twenty municipal STPs. This was done through direct involvement with the plant personnel and the results were scaled up to cover all treatment plants larger than 2000 person equivalents in the Swedish tributary areas of the Kattegat and the Baltic Proper. The sum of costs and nitrogen reductions were compared with an assumed command-and-control regulation requiring all STPs to obtain 80% total nitrogen reduction in their effluents. Costs for the latter case were estimated using a database containing standard estimates for reduction costs by six specified measures. For both cases a total reduction target of 3000 tonnes of nitrogen was set. We did not find that the emissions payment system was more efficient in terms of total reduction costs, although some practical and administrative advantages could be identified. Our results emphasize the need to evaluate the performance of policy instruments on a case-by-case basis since the theoretical efficiency is not always reflected in practice. Copyright © 2015 Elsevier Ltd. All rights reserved.

Promoted decomposition of NOx in automotive diesel-like exhausts by electro-catalytic honeycombs.

PubMed

Huang, Ta-Jen; Chiang, De-Yi; Shih, Chi; Lee, Cheng-Chin; Mao, Chih-Wei; Wang, Bo-Chung

2015-03-17

NO and NO2 (collectively called NOx) are major air pollutants in automotive emissions. More effective and easier treatments of NOx than those achieved by the present methods can offer better protection of human health and higher fuel efficiency that can reduce greenhouse gas emissions. However, currently commercialized technologies for automotive NOx emission control cannot effectively treat diesel-like exhausts with high NOx concentrations. Thus, exhaust gas recirculation (EGR) has been used extensively, which reduces fuel efficiency and increases particulate emission considerably. Our results show that the electro-catalytic honeycomb (ECH) promotes the decomposition of NOx to nitrogen and oxygen, without consuming reagents or other resources. NOx can be converted to nitrogen and oxygen almost completely. The ECHs are shown to effectively remove NOx from gasoline-fueled diesel-like exhausts. A very high NO concentration is preferred in the engine exhaust, especially during engine cold-start. Promoted NOx decomposition (PND) technology for real-world automotive applications is established in this study by using the ECH. With PND, EGR is no longer needed. Diesel-like engines can therefore achieve superior fuel efficiency, and all major automotive pollutants can be easily treated due to high concentration of oxygen in the diesel-like exhausts, leading to zero pollution.

Photoacoustic emission from Au nanoparticles arrayed on thermal insulation layer.

PubMed

Namura, Kyoko; Suzuki, Motofumi; Nakajima, Kaoru; Kimura, Kenji

2013-04-08

Efficient photoacoustic emission from Au nanoparticles on a porous SiO(2) layer was investigated experimentally and theoretically. The Au nanoparticle arrays/porous SiO(2)/SiO(2)/Ag mirror sandwiches, namely, local plasmon resonators, were prepared by dynamic oblique deposition (DOD). Photoacoustic measurements were performed on the local plasmon resonators, whose optical absorption was varied from 0.03 (3%) to 0.95 by varying the thickness of the dielectric SiO(2) layer. The sample with high absorption (0.95) emitted a sound that was eight times stronger than that emitted by graphite (0.94) and three times stronger than that emitted by the sample without the porous SiO(2) layer (0.93). The contribution of the porous SiO(2) layer to the efficient photoacoustic emission was analyzed by means of a numerical method based on a one-dimensional heat transfer model. The result suggested that the low thermal conductivity of the underlying porous layer reduces the amount of heat escaping from the substrate and contributes to the efficient photoacoustic emission from Au nanoparticle arrays. Because both the thermal conductivity and the spatial distribution of the heat generation can be controlled by DOD, the local plasmon resonators produced by DOD are suitable for the spatio-temporal modulation of the local temperature.

Active Tuning of Spontaneous Emission by Mie-Resonant Dielectric Metasurfaces.

PubMed

Bohn, Justus; Bucher, Tobias; Chong, Katie E; Komar, Andrei; Choi, Duk-Yong; Neshev, Dragomir N; Kivshar, Yuri S; Pertsch, Thomas; Staude, Isabelle

2018-06-13

Mie-resonant dielectric metasurfaces offer comprehensive opportunities for the manipulation of light fields with high efficiency. Additionally, various strategies for the dynamic tuning of the optical response of such metasurfaces were demonstrated, making them important candidates for reconfigurable optical devices. However, dynamic control of the light-emission properties of active Mie-resonant dielectric metasurfaces by an external control parameter has not been demonstrated so far. Here, we experimentally demonstrate the dynamic tuning of spontaneous emission from a Mie-resonant dielectric metasurface that is situated on a fluorescent substrate and embedded into a liquid crystal cell. By switching the liquid crystal from the nematic state to the isotropic state via control of the cell temperature, we induce a shift of the spectral position of the metasurface resonances. This results in a change of the local photonic density of states, which, in turn, governs the enhancement of spontaneous emission from the substrate. Specifically, we observe spectral tuning of both the electric and magnetic dipole resonances, resulting in a 2-fold increase of the emission intensity at λ ≈ 900 nm. Our results demonstrate a viable strategy to realize flat tunable light sources based on dielectric metasurfaces.

Analysis of the impact path on factors of China's energy-related CO2 emissions: a path analysis with latent variables.

PubMed

Chen, Wenhui; Lei, Yalin

2017-02-01

Identifying the impact path on factors of CO 2 emissions is crucial for the government to take effective measures to reduce carbon emissions. The most existing research focuses on the total influence of factors on CO 2 emissions without differentiating between the direct and indirect influence. Moreover, scholars have addressed the relationships among energy consumption, economic growth, and CO 2 emissions rather than estimating all the causal relationships simultaneously. To fill this research gaps and explore overall driving factors' influence mechanism on CO 2 emissions, this paper utilizes a path analysis model with latent variables (PA-LV) to estimate the direct and indirect effect of factors on China's energy-related carbon emissions and to investigate the causal relationships among variables. Three key findings emanate from the analysis: (1) The change in the economic growth pattern inhibits the growth rate of CO 2 emissions by reducing the energy intensity; (2) adjustment of industrial structure contributes to energy conservation and CO 2 emission reduction by raising the proportion of the tertiary industry; and (3) the growth of CO 2 emissions impacts energy consumption and energy intensity negatively, which results in a negative impact indirectly on itself. To further control CO 2 emissions, the Chinese government should (1) adjust the industrial structure and actively develop its tertiary industry to improve energy efficiency and develop low-carbon economy, (2) optimize population shifts to avoid excessive population growth and reduce energy consumption, and (3) promote urbanization steadily to avoid high energy consumption and low energy efficiency.

Measurement and comparison of Bangkok diesel bus emissions and performance using on-board equipment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burnette, A.D.; Kishan, S.; Wangwongwatana, S.

1997-12-31

An on-board measurement system was assembled and used to compare the emissions and performance of buses in Bangkok, Thailand under actual driving conditions. Three similar buses were compared: one using an engine without special emissions control design, one with an engine meeting Euro 1 standards, and one with an engine meeting Euro 2 standards. As the buses drove their routes, second-by-second data were collected for engine rpm, throttle position, vehicle speed, exhaust concentrations of hydrocarbons, carbon monoxide, carbon dioxide, oxygen, nitric oxide, and exhaust opacity. Vehicle performance data were calculated using algorithms developed during previous driving studies in Bangkok. Grammore » per liter of fuel used emission factors were developed for gaseous pollutants using combustion calculations and these were translated into gram per kilometer traveled emission factors using the fuel efficiency data for the buses. Smoke data were left in terms of opacity. Test results are designed to be used to compare the cost benefit of upgrading buses with no emissions controls to Euro 1 or Euro 2 technologies. Ongoing tests will help bus companies determine the benefit of incremental improvements to bus engines and other emissions reduction strategies.« less

Effect of inlet temperature on the performance of a catalytic reactor. [air pollution control

NASA Technical Reports Server (NTRS)

Anderson, D. N.

1978-01-01

A 12 cm diameter by 15 cm long catalytic reactor was tested with No. 2 diesel fuel in a combustion test rig at inlet temperatures of 700, 800, 900, and 1000 K. Other test conditions included pressures of 3 and 6 x 10 to the 5th power Pa, reference velocities of 10, 15, and 20 m/s, and adiabatic combustion temperatures in the range 1100 to 1400 K. The combustion efficiency was calculated from measurements of carbon monoxide and unburned hydrocarbon emissions. Nitrogen oxide emissions and reactor pressure drop were also measured. At a reference velocity of 10 m/s, the CO and unburned hydrocarbons emissions, and, therefore, the combustion efficiency, were independent of inlet temperature. At an inlet temperature of 1000 K, they were independent of reference velocity. Nitrogen oxides emissions resulted from conversion of the small amount (135 ppm) of fuel-bound nitrogen in the fuel. Up to 90 percent conversion was observed with no apparent effect of any of the test variables. For typical gas turbine operating conditions, all three pollutants were below levels which would permit the most stringent proposed automotive emissions standards to be met.

Trends in onroad transportation energy and emissions.

PubMed

Frey, H Christopher

2018-06-01

Globally, 1.3 billion on-road vehicles consume 79 quadrillion BTU of energy, mostly gasoline and diesel fuels, emit 5.7 gigatonnes of CO 2 , and emit other pollutants to which approximately 200,000 annual premature deaths are attributed. Improved vehicle energy efficiency and emission controls have helped offset growth in vehicle activity. New technologies are diffusing into the vehicle fleet in response to fuel efficiency and emission standards. Empirical assessment of vehicle emissions is challenging because of myriad fuels and technologies, intervehicle variability, multiple emission processes, variability in operating conditions, and varying capabilities of measurement methods. Fuel economy and emissions regulations have been effective in reducing total emissions of key pollutants. Real-world fuel use and emissions are consistent with official values in the United States but not in Europe or countries that adopt European standards. Portable emission measurements systems, which uncovered a recent emissions cheating scandal, have a key role in regulatory programs to ensure conformity between "real driving emissions" and emission standards. The global vehicle fleet will experience tremendous growth, especially in Asia. Although existing data and modeling tools are useful, they are often based on convenience samples, small sample sizes, large variability, and unquantified uncertainty. Vehicles emit precursors to several important secondary pollutants, including ozone and secondary organic aerosols, which requires a multipollutant emissions and air quality management strategy. Gasoline and diesel are likely to persist as key energy sources to mid-century. Adoption of electric vehicles is not a panacea with regard to greenhouse gas emissions unless coupled with policies to change the power generation mix. Depending on how they are actually implemented and used, autonomous vehicles could lead to very large reductions or increases in energy consumption. Numerous other trends are addressed with regard to technology, emissions controls, vehicle operations, emission measurements, impacts on exposure, and impacts on public health. Without specific policies to the contrary, fossil fuels are likely to continue to be the major source of on-road vehicle energy consumption. Fuel economy and emission standards are generally effective in achieving reductions per unit of vehicle activity. However, the number of vehicles and miles traveled will increase. Total energy use and emissions depend on factors such as fuels, technologies, land use, demographics, economics, road design, vehicle operation, societal values, and others that affect demand for transportation, mode choice, energy use, and emissions. Thus, there are many opportunities to influence future trends in vehicle energy use and emissions.

Growth of Nanosized Single Crystals for Efficient Perovskite Light-Emitting Diodes.

PubMed

Lee, Seungjin; Park, Jong Hyun; Nam, Yun Seok; Lee, Bo Ram; Zhao, Baodan; Di Nuzzo, Daniele; Jung, Eui Dae; Jeon, Hansol; Kim, Ju-Young; Jeong, Hu Young; Friend, Richard H; Song, Myoung Hoon

2018-04-24

Organic-inorganic hybrid perovskites are emerging as promising emitting materials due to their narrow full-width at half-maximum emissions, color tunability, and high photoluminescence quantum yields (PLQYs). However, the thermal generation of free charges at room temperature results in a low radiative recombination rate and an excitation-intensity-dependent PLQY, which is associated with the trap density. Here, we report perovskite films composed of uniform nanosized single crystals (average diameter = 31.7 nm) produced by introducing bulky amine ligands and performing the growth at a lower temperature. By effectively controlling the crystal growth, we maximized the radiative bimolecular recombination yield by reducing the trap density and spatially confining the charges. Finally, highly bright and efficient green emissive perovskite light-emitting diodes that do not suffer from electroluminescence blinking were achieved with a luminance of up to 55 400 cd m -2 , current efficiency of 55.2 cd A -1 , and external quantum efficiency of 12.1%.

Emission factors of particulate matter, polycyclic aromatic hydrocarbons, and levoglucosan from wood combustion in south-central Chile.

PubMed

Jimenez, Jorge; Farias, Oscar; Quiroz, Roberto; Yañez, Jorge

2017-07-01

In south-central Chile, wood stoves have been identified as an important source of air pollution in populated areas. Eucalyptus (Eucalyptus globulus), Chilean oak (Nothofagus oblique), and mimosa (Acacia dealbata) were burned in a single-chamber slow-combustion wood stove at a controlled testing facility located at the University of Concepción, Chile. In each experiment, 2.7-3.1 kg of firewood were combusted while continuously monitoring temperature, exhaust gases, burn rate, and collecting particulate matter samples in Teflon filters under isokinetic conditions for polycyclic aromatic hydrocarbon and levoglucosan analyses. Mean particulate matter emission factors were 2.03, 4.06, and 3.84 g/kg dry wood for eucalyptus, oak, and mimosa, respectively. The emission factors were inversely correlated with combustion efficiency. The mean emission factors of the sums of 12 polycyclic aromatic hydrocarbons in particle phases were 1472.5, 2134.0, and 747.5 μg/kg for eucalyptus, oak, and mimosa, respectively. Fluoranthene, pyrene, benzo[a]anthracene, and chrysene were present in the particle phase in higher proportions compared with other polycyclic aromatic hydrocarbons that were analyzed. Mean levoglucosan emission factors were 854.9, 202.3, and 328.0 mg/kg for eucalyptus, oak, and mimosa, respectively. Since the emissions of particulate matter and other pollutants were inversely correlated with combustion efficiency, implementing more efficient technologies would help to reduce air pollutant emissions from wood combustion. Residential wood burning has been identified as a significant source of air pollution in populated areas. Local wood species are combusted for home cooking and heating, which releases several toxic air pollutants, including particulate matter, carbon monoxide, and polycyclic aromatic hydrocarbons. Air pollutant emissions depend on the type of wood and the technology and operational conditions of the wood stove. A better understanding of emissions from local wood species and wood stove performance would help to identify better biomass fuels and wood stove technologies in order to reduce air pollution from residential wood burning.

Air quality management in China: issues, challenges, and options.

PubMed

Wang, Shuxiao; Hao, Jiming

2012-01-01

This article analyzed the control progress and current status of air quality, identified the major air pollution issues and challenges in future, proposed the long-term air pollution control targets, and suggested the options for better air quality in China. With the continuing growth of economy in the next 10-15 years, China will face a more severe situation of energy consumption, electricity generation and vehicle population leading to increase in multiple pollutant emissions. Controlling regional air pollution especially fine particles and ozone, as well as lowering carbon emissions from fossil fuel consumption will be a big challenge for the country. To protect public health and the eco-system, the ambient air quality in all Chinese cities shall attain the national ambient air quality standards (NAAQS) and ambient air quality guideline values set by the World Health Organization (WHO). To achieve the air quality targets, the emissions of SO2, NOx, PM10, and volatile organic compounds (VOC) should decrease by 60%, 40%, 50%, and 40%, respectively, on the basis of that in 2005. A comprehensive control policy focusing on multiple pollutants and emission sources at both the local and regional levels was proposed to mitigate the regional air pollution issue in China. The options include development of clean energy resources, promotion of clean and efficient coal use, enhancement of vehicle pollution control, implementation of synchronous control of multiple pollutants including SO2, NOx, VOC, and PM emissions, joint prevention and control of regional air pollution, and application of climate friendly air pollution control measures.

Simulations of the Fuel Economy and Emissions of Hybrid Transit Buses over Planned Local Routes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, Zhiming; LaClair, Tim J; Daw, C Stuart

2014-01-01

We present simulated fuel economy and emissions city transit buses powered by conventional diesel engines and diesel-hybrid electric powertrains of varying size. Six representative city drive cycles were included in the study. In addition, we included previously published aftertreatment device models for control of CO, HC, NOx, and particulate matter (PM) emissions. Our results reveal that bus hybridization can significantly enhance fuel economy by reducing engine idling time, reducing demands for accessory loads, exploiting regenerative braking, and shifting engine operation to speeds and loads with higher fuel efficiency. Increased hybridization also tends to monotonically reduce engine-out emissions, but trends inmore » the tailpipe (post-aftertreatment) emissions involve more complex interactions that significantly depend on motor size and drive cycle details.« less

Catalytic Combustion for Ultra-Low NOx Hydrogen Turbines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Etemad, Shahrokh; Baird, Benjamin; Alavandi, Sandeep

2011-06-30

Precision Combustion, Inc., (PCI) in close collaboration with Solar Turbines, Incorporated, has developed and demonstrated a combustion system for hydrogen fueled turbines that reduces NOx to low single digit level while maintaining or improving current levels of efficiency and eliminating emissions of carbon dioxide. Full scale Rich Catalytic Hydrogen (RCH1) injector was developed and successfully tested at Solar Turbines, Incorporated high pressure test facility demonstrating low single digit NOx emissions for hydrogen fuel in the range of 2200F-2750F. This development work was based on initial subscale development for faster turnaround and reduced cost. Subscale testing provided promising results for 42%more » and 52% H2 with NOx emissions of less than 2 ppm with improved flame stability. In addition, catalytic reactor element testing for substrate oxidation, thermal cyclic injector testing to simulate start-stop operation in a gas turbine environment, and steady state 15 atm. operation testing were performed successfully. The testing demonstrated stable and robust catalytic element component life for gas turbine conditions. The benefit of the catalytic hydrogen combustor technology includes capability of delivering near-zero NOx without costly post-combustion controls and without requirement for added sulfur control. In addition, reduced acoustics increase gas turbine component life. These advantages advances Department of Energy (DOE’s) objectives for achievement of low single digit NOx emissions, improvement in efficiency vs. postcombustion controls, fuel flexibility, a significant net reduction in Integrated Gasification Combined Cycle (IGCC) system net capital and operating costs, and a route to commercialization across the power generation field from micro turbines to industrial and utility turbines.« less

Combining biochar, zeolite and wood vinegar for composting of pig manure: The effect on greenhouse gas emission and nitrogen conservation.

PubMed

Wang, Quan; Awasthi, Mukesh Kumar; Ren, Xiuna; Zhao, Junchao; Li, Ronghua; Wang, Zhen; Wang, Meijing; Chen, Hongyu; Zhang, Zengqiang

2018-04-01

The effect of enhancing wood vinegar (WV) with a mixture of biochar (B) and zeolite (Z) to compost pig manure (PM) in a 130 L reactor was evaluated to determine the levels of greenhouse gas (GHG) and ammonia emissions. Six treatments were prepared in a 2:1 ratio of PM mixed with wheat straw (WS; dry weight basis): PM + WS (control), PM + WS + 10%B, PM + WS + 10%B + 10%Z, and PM + WS with 0.5%, 1.0% and 2.0%WV combined with 10%B + 10%Z. These were composted for 50 days, and the results indicated that the combined use of B, Z, and WV could shorten the thermophilic phase and improve the maturity of compost compared to the control treatment. In addition, WV mixed with B and Z could reduce ammonia loss by 64.45-74.32% and decrease CO 2 , CH 4 , and N 2 O emissions by 33.90-46.98%, 50.39-61.15%, and 79.51-81.10%, respectively. Furthermore, compared to treatments in which B and B + Z were added, adding WV was more efficient to reduce the nitrogen and carbon loss, and the 10%B + 10%Z + 2%WV treatment presented the lowest loss of carbon (9.16%) and nitrogen (0.75%). Based on the maturity indexes used, nitrogen conservation, and efficiency of GHG emissions reduction, the treatment 10%B + 10%Z + 2%WV is suggested for efficient PM composting. Copyright © 2018 Elsevier Ltd. All rights reserved.

Emissions of polycyclic aromatic hydrocarbons from batch hot mix asphalt plants.

PubMed

Lee, Wen-Jhy; Chao, Wen-Hui; Shih, Minliang; Tsai, Cheng-Hsien; Chen, Thomas Jeng-Ho; Tsai, Perng-Jy

2004-10-15

This study was set out to assess the characteristics of polycyclic aromatic hydrocarbon (PAH) emissions from batch hot mix asphalt (HMA) plants and PAH removal efficiencies associated with their installed air pollution control devices. Field samplings were conducted on six randomly selected batch HMA plants. For each selected plant, stack flue gas samples were collected from both stacks of the batch mixer (n = 5) and the preheating boiler (n = 5), respectively. PAH samples were also collected from the field to assess PAHs that were directly emitted from the discharging chute (n = 3). To assess PAH removal efficiencies of the installed air pollution control devices, PAH contents in both cyclone fly ash (n=3) and bag filter fly ash (n = 3) were analyzed. Results show that the total PAH concentration (mean; RSD) in the stack flue gas of the batch mixer (354 microg/Nm3; 78.5%) was higher than that emitted from the discharging chute (107 microg/Nm3; 70.1%) and that in the stack flue gas of the preheating boiler (83.7 microg/Nm3; 77.6%). But the total BaPeq concentration of that emitted from the discharging chute (0.950 microg/Nm3; 84.4%) was higher than contained in the stack flue gas of the batch mixer (0.629 microg/Nm3; 86.8%) and the stack flue gas of the preheating boiler (= 0.112 microg/Nm3; 80.3%). The mean total PAH emission factor for all selected batch mix plants (= 139 mg/ton x product) was much higher than that reported by U.S. EPA for the drum mix asphalt plant (range = 11.8-79.0 mg/ton x product). We found the overall removal efficiency of the installed air pollution control devices (i.e., cyclone + bag filter) on total PAHs and total BaPeq were 22.1% and 93.7%, respectively. This implies that the installed air pollution control devices, although they have a very limited effect on the removal of total PAHs, do significantly reduce the carcinogenic potencies associated with PAH emissions from batch HMA plants.

The response of nitrous oxide emissions to different operating conditions in activated sludge wastewater treatment plants in Southeastern Brazil.

PubMed

Ribeiro, Renato P; Bueno, Rodrigo F; Piveli, Roque P; Kligerman, Débora C; de Mello, William Z; Oliveira, Jaime L M

2017-11-01

The continuous measurements of N 2 O emissions from the aeration tanks of three activated sludge wastewater treatment plants (WWTPs) operated with biological nitrogen removal (BNR) and non-BNR were performed during the different operating conditions of several parameters, such as aeration, dissolved oxygen (DO) profiling and organic shock loading (with landfill leachate). The nitrification process is the main driving force behind N 2 O emission peaks. There are indications that the variation of the air flow rate influenced N 2 O emissions; high N 2 O emissions denote over-aeration conditions or incomplete nitrification, with accumulation of NO 2 - concentrations. Thus, continuous measurements of N 2 O emissions can provide information on aeration adequacy and the efficiency of complete nitrification, with major focus on DO control, in order to reduce N 2 O emissions. An additional concern is the observed propensity of WWTPs in developing countries to receive landfill leachates in their wastewater systems. This practice could have adverse effects on climate change, since wastewater treatment during periods of organic shock loading emitted significantly higher amounts of N 2 O than without organic shock loading. In short, non-BNR WWTPs are subject to high N 2 O emissions, in contrast to BNR WWTP with controlled nitrification and denitrification processes.

Energy efficient engine combustor test hardware detailed design report

NASA Technical Reports Server (NTRS)

Zeisser, M. H.; Greene, W.; Dubiel, D. J.

1982-01-01

The combustor for the Energy Efficient Engine is an annular, two-zone component. As designed, it either meets or exceeds all program goals for performance, safety, durability, and emissions, with the exception of oxides of nitrogen. When compared to the configuration investigated under the NASA-sponsored Experimental Clean Combustor Program, which was used as a basis for design, the Energy Efficient Engine combustor component has several technology advancements. The prediffuser section is designed with short, strutless, curved-walls to provide a uniform inlet airflow profile. Emissions control is achieved by a two-zone combustor that utilizes two types of fuel injectors to improve fuel atomization for more complete combustion. The combustor liners are a segmented configuration to meet the durability requirements at the high combustor operating pressures and temperatures. Liner cooling is accomplished with a counter-parallel FINWALL technique, which provides more effective heat transfer with less coolant.

Further theoretical studies of modified cyclone separator as a diesel soot particulate emission arrester.

PubMed

Mukhopadhyay, N; Bose, P K

2009-10-01

Soot particulate emission reduction from diesel engine is one of the most emerging problems associated with the exhaust pollution. Diesel particulate filters (DPF) hold out the prospects of substantially reducing regulated particulate emissions but the question of the reliable regeneration of filters still remains a difficult hurdle to overcome. Many of the solutions proposed to date suffer from design complexity, cost, regeneration problem and energy demands. This study presents a computer aided theoretical analysis for controlling diesel soot particulate emission by cyclone separator--a non contact type particulate removal system considering outer vortex flow, inner vortex flow and packed ceramic fiber filter at the end of vortex finder tube. Cyclone separator with low initial cost, simple construction produces low back pressure and reasonably high collection efficiencies with reduced regeneration problems. Cyclone separator is modified by placing a continuous ceramic packed fiber filter placed at the end of the vortex finder tube. In this work, the grade efficiency model of diesel soot particulate emission is proposed considering outer vortex, inner vortex and the continuous ceramic packed fiber filter. Pressure drop model is also proposed considering the effect of the ceramic fiber filter. Proposed model gives reasonably good collection efficiency with permissible pressure drop limit of diesel engine operation. Theoretical approach is predicted for calculating the cut size diameter considering the effect of Cunningham molecular slip correction factor. The result shows good agreements with existing cyclone and DPF flow characteristics.

Manipulating Smith-Purcell Emission with Babinet Metasurfaces

NASA Astrophysics Data System (ADS)

Wang, Zuojia; Yao, Kan; Chen, Min; Chen, Hongsheng; Liu, Yongmin

2016-10-01

Swift electrons moving closely parallel to a periodic grating produce far-field radiation of light, which is known as the Smith-Purcell effect. In this letter, we demonstrate that designer Babinet metasurfaces composed of C -aperture resonators offer a powerful control over the polarization state of the Smith-Purcell emission, which can hardly be achieved via traditional gratings. By coupling the intrinsically nonradiative energy bound at the source current sheet to the out-of-plane electric dipole and in-plane magnetic dipole of the C -aperture resonator, we are able to excite cross-polarized light thanks to the bianisotropic nature of the metasurface. The polarization direction of the emitted light is aligned with the orientation of the C -aperture resonator. Furthermore, the efficiency of the Smith-Purcell emission from Babinet metasurfaces is significantly increased by 84%, in comparison with the case of conventional gratings. These findings not only open up a new way to manipulate the electron-beam-induced emission in the near-field region but also promise compact, tunable, and efficient light sources and particle detectors.

Manipulating Smith-Purcell Emission with Babinet Metasurfaces.

PubMed

Wang, Zuojia; Yao, Kan; Chen, Min; Chen, Hongsheng; Liu, Yongmin

2016-10-07

Swift electrons moving closely parallel to a periodic grating produce far-field radiation of light, which is known as the Smith-Purcell effect. In this letter, we demonstrate that designer Babinet metasurfaces composed of C-aperture resonators offer a powerful control over the polarization state of the Smith-Purcell emission, which can hardly be achieved via traditional gratings. By coupling the intrinsically nonradiative energy bound at the source current sheet to the out-of-plane electric dipole and in-plane magnetic dipole of the C-aperture resonator, we are able to excite cross-polarized light thanks to the bianisotropic nature of the metasurface. The polarization direction of the emitted light is aligned with the orientation of the C-aperture resonator. Furthermore, the efficiency of the Smith-Purcell emission from Babinet metasurfaces is significantly increased by 84%, in comparison with the case of conventional gratings. These findings not only open up a new way to manipulate the electron-beam-induced emission in the near-field region but also promise compact, tunable, and efficient light sources and particle detectors.

Deep-UV emission at 219 nm from ultrathin MBE GaN/AlN quantum heterostructures

NASA Astrophysics Data System (ADS)

Islam, S. M.; Protasenko, Vladimir; Lee, Kevin; Rouvimov, Sergei; Verma, Jai; Xing, Huili Grace; Jena, Debdeep

2017-08-01

Deep ultraviolet (UV) optical emission below 250 nm (˜5 eV) in semiconductors is traditionally obtained from high aluminum containing AlGaN alloy quantum wells. It is shown here that high-quality epitaxial ultrathin binary GaN quantum disks embedded in an AlN matrix can produce efficient optical emission in the 219-235 nm (˜5.7-5.3 eV) spectral range, far above the bulk bandgap (3.4 eV) of GaN. The quantum confinement energy in these heterostructures is larger than the bandgaps of traditional semiconductors, made possible by the large band offsets. These molecular beam epitaxy-grown extreme quantum-confinement GaN/AlN heterostructures exhibit an internal quantum efficiency of 40% at wavelengths as short as 219 nm. These observations together with the ability to engineer the interband optical matrix elements to control the direction of photon emission in such binary quantum disk active regions offer unique advantages over alloy AlGaN quantum well counterparts for the realization of deep-UV light-emitting diodes and lasers.

Survey of Emissions Associated with Enclosed Combustor Emission Control Devices in the Denver-Julesburg Basin

NASA Astrophysics Data System (ADS)

Knighton, W. B.; Floerchinger, C. R.; Wormhoult, J.; Massoli, P.; Fortner, E.; Brooks, B.; Roscioli, J. R.; Bon, D.; Herndon, S. C.

2014-12-01

Volatile organic compounds (VOCs) play an important role in local and regional air quality. A large source of VOCs comes from the oil and gas industry and the Denver-Julesburg Basin (D-J Basin) has seen a sharp increase in production in recent years primarily due to advances in horizontal drilling techniques. To help curb emissions with extraction and production of natural gas and its associated oil, emission control devices are required for facilities emitting over 6 tons of hydrocarbons per year. Within the ozone non-attainment area, which encompasses Denver and much of the front range, enclosed combustion devices (enclosed flares) are required to reduce hydrocarbon emissions by at least 95%. While certification tests indicate that these enclosed combustor devices provide high destruction removal efficiencies, there is considerable interest in knowing how well they perform in the field. As part of Front Range Air Pollution and Photochemistry Experiment (FRAPPE) project conducted during the Summer of 2014, the Aerodyne Mobile Laboratory (AML) surveyed oil and gas operations within the Wattenberg gas field and the surrounding D-J Basin. The AML deployed a full suite of gas and particle phase instrumentation providing a comprehensive set of on-line, real-time measurements for the major natural gas components (methane and ethane) and their combustion products (CO2, CO, NOx) using a variety of spectroscopic techniques. Additional gas phase organic gas emissions were made using a proton transfer reaction mass spectrometer (PTR-MS). Particle number and composition were determined using a condensation particle counter and an Aerodyne Aerosol Mass Spectrometer (AMS). A summary of the number of enclosed combustor devices measured and their observed combustion efficiencies will be presented.

Reactivity-controlled compression ignition drive cycle emissions and fuel economy estimations using vehicle system simulations

DOE PAGES

Curran, Scott J.; Gao, Zhiming; Wagner, Robert M.

2014-12-22

In-cylinder blending of gasoline and diesel to achieve reactivity-controlled compression ignition has been shown to reduce NO X and soot emissions while maintaining or improving brake thermal efficiency as compared with conventional diesel combustion. The reactivity-controlled compression ignition concept has an advantage over many advanced combustion strategies in that the fuel reactivity can be tailored to the engine speed and load, allowing stable low-temperature combustion to be extended over more of the light-duty drive cycle load range. In this paper, a multi-mode reactivity-controlled compression ignition strategy is employed where the engine switches from reactivity-controlled compression ignition to conventional diesel combustionmore » when speed and load demand are outside of the experimentally determined reactivity-controlled compression ignition range. The potential for reactivity-controlled compression ignition to reduce drive cycle fuel economy and emissions is not clearly understood and is explored here by simulating the fuel economy and emissions for a multi-mode reactivity-controlled compression ignition–enabled vehicle operating over a variety of US drive cycles using experimental engine maps for multi-mode reactivity-controlled compression ignition, conventional diesel combustion, and a 2009 port-fuel injected gasoline engine. Drive cycle simulations are completed assuming a conventional mid-size passenger vehicle with an automatic transmission. Multi-mode reactivity-controlled compression ignition fuel economy simulation results are compared with the same vehicle powered by a representative 2009 port-fuel injected gasoline engine over multiple drive cycles. Finally, engine-out drive cycle emissions are compared with conventional diesel combustion, and observations regarding relative gasoline and diesel tank sizes needed for the various drive cycles are also summarized.« less

Likelihood of achieving air quality targets under model uncertainties.

PubMed

Digar, Antara; Cohan, Daniel S; Cox, Dennis D; Kim, Byeong-Uk; Boylan, James W

2011-01-01

Regulatory attainment demonstrations in the United States typically apply a bright-line test to predict whether a control strategy is sufficient to attain an air quality standard. Photochemical models are the best tools available to project future pollutant levels and are a critical part of regulatory attainment demonstrations. However, because photochemical models are uncertain and future meteorology is unknowable, future pollutant levels cannot be predicted perfectly and attainment cannot be guaranteed. This paper introduces a computationally efficient methodology for estimating the likelihood that an emission control strategy will achieve an air quality objective in light of uncertainties in photochemical model input parameters (e.g., uncertain emission and reaction rates, deposition velocities, and boundary conditions). The method incorporates Monte Carlo simulations of a reduced form model representing pollutant-precursor response under parametric uncertainty to probabilistically predict the improvement in air quality due to emission control. The method is applied to recent 8-h ozone attainment modeling for Atlanta, Georgia, to assess the likelihood that additional controls would achieve fixed (well-defined) or flexible (due to meteorological variability and uncertain emission trends) targets of air pollution reduction. The results show that in certain instances ranking of the predicted effectiveness of control strategies may differ between probabilistic and deterministic analyses.

Controlled electroluminescence of n-ZnMgO/p-GaN light-emitting diodes

NASA Astrophysics Data System (ADS)

Goh, E. S. M.; Yang, H. Y.; Han, Z. J.; Chen, T. P.; Ostrikov, K.

2012-12-01

Effective control of room-temperature electroluminescence of n-ZnMgO/p-GaN light-emitting diodes (LEDs) over both emission intensity and wavelength is demonstrated. With varied Mg concentration, the intensity of LEDs in the near-ultraviolet region is increased due to the effective radiative recombination in the ZnMgO layer. Furthermore, the emission wavelength is shifted to the green/yellow spectral region by employing an indium-tin-oxide thin film as the dopant source, where thermally activated indium diffusion creates extra deep defect levels for carrier recombination. These results clearly demonstrate the effectiveness of controlled metal incorporation in achieving high energy efficiency and spectral tunability of the n-ZnMgO/p-GaN LED devices.

Current and Future Greenhouse Gas Emissions from Global Crop Intensification and Expansion

NASA Astrophysics Data System (ADS)

Carlson, K. M.; Gerber, J. S.; Mueller, N. D.; O'Connell, C.; West, P. C.

2014-12-01

Food systems currently contribute up to one-third of total anthropogenic greenhouse gas emissions, and these emissions are expected to rise as demand for agricultural products increases. Thus, improving the greenhouse gas emissions efficiency of agriculture - the tons or kilocalories of production per ton of CO2 equivalent emissions - will be critical to support a resilient future global system. Here, we model and evaluate global, 2000-era, spatially explicit relationships between a suite of greenhouse gas emissions from various agronomic practices (i.e., fertilizer application, peatland draining, and rice cultivation) and crop yields. Then, we predict potential emissions from future crop production increases achieved through intensification and extensification, including CO2 emissions from croplands replacing non-urban land cover. We find that 2000-era yield-scaled agronomic emissions are highly heterogeneous across crops types, crop management practices, and regions. Rice agriculture produces more total CO2-equivalent emissions than any other crop. Moreover, inundated rice in just a few countries contributes the vast majority of these rice emissions. Crops such as sunflower and cotton have low efficiency on a caloric basis. Our results suggest that intensification tends to be a more efficient pathway to boost greenhouse gas emissions efficiency than expansion. We conclude by discussing potential crop- and region-specific agricultural development pathways that may boost the greenhouse gas emissions efficiency of agriculture.

Criteria pollutant and greenhouse gas emissions from CNG transit buses equipped with three-way catalysts compared to lean-burn engines and oxidation catalyst technologies.

PubMed

Yoon, Seungju; Collins, John; Thiruvengadam, Arvind; Gautam, Mridul; Herner, Jorn; Ayala, Alberto

2013-08-01

Engine and exhaust control technologies applied to compressed natural gas (CNG) transit buses have advanced from lean-burn, to lean-burn with oxidation catalyst (OxC), to stoichiometric combustion with three-way catalyst (TWC). With this technology advancement, regulated gaseous and particulate matter emissions have been significantly reduced. Two CNG transit buses equipped with stoichiometric combustion engines and TWCs were tested on a chassis dynamometer, and their emissions were measured. Emissions from the stoichiometric engines with TWCs were then compared to the emissions from lean-burn CNG transit buses tested in previous studies. Stoichiometric combustion with TWC was effective in reducing emissions of oxides of nitrogen (NO(x)), particulate matter (PM), and nonmethane hydrocarbon (NMHC) by 87% to 98% depending on pollutants and test cycles, compared to lean combustion. The high removal efficiencies exceeded the emission reduction required from the certification standards, especially for NO(x) and PM. While the certification standards require 95% and 90% reductions for NO(x) and PM, respectively, from the engine model years 1998-2003 to the engine model year 2007, the measured NO(x) and PM emissions show 96% and 95% reductions, respectively, from the lean-burn engines to the stoichiometric engines with TWC over the transient Urban Dynamometer Driving Schedule (UDDS) cycle. One drawback of stoichiometric combustion with TWC is that this technology produces higher carbon monoxide (CO) emissions than lean combustion. In regard to controlling CO emissions, lean combustion with OxC is more effective than stoichiometric combustion. Stoichiometric combustion with TWC produced higher greenhouse gas (GHG) emissions including carbon dioxide (CO2) and methane (CH4) than lean combustion during the UDDS cycle, but lower GHG emissions during the steady-state cruise cycle. Stoichiometric combustion with three-way catalyst is currently the best emission control technology available for compressed natural gas (CNG) transit buses to meet the stringent U.S. Environmental Protection Agency (EPA) 2010 heavy-duty engine NO(x) emissions standard. For existing lean-burn CNG transit buses in the fleet, oxidation catalyst would be the most effective retrofit technology for the control of NMHC and CO emissions.

A Framework for Evaluating Energy and Emissions of Connected and Automated Vehicles through Traffic Microsimulations

DOT National Transportation Integrated Search

2018-01-07

Connected and automated vehicles (CAV) are poised to transform surface transportation systems in the United States. Near-term CAV technologies like cooperative adaptive cruise control (CACC) have the potential to deliver energy efficiency and air qua...

Emissions Removal Efficiency from Diesel Gensets Using Aftermarket PM Controls

EPA Science Inventory

Diesel particulate matter (PM) has been associated with adverse health effects in humans and is classified as a human carcinogen. Additionally, diesel PM, particularly the strongly light absorbing fraction, black carbon (BC), is an important climate forcer. The adverse impacts ...

40 CFR Table 1 of Subpart Bbbbbbb... - Emission Reduction and PM Concentration Requirements

Code of Federal Regulations, 2013 CFR

2013-07-01

... from equipment in target HAP service Route the process vent stream to a PM control device with:a. A PM percent reduction efficiency of 95 percent (98 percent for new sources), or b. An outlet concentration of...

40 CFR Table 1 of Subpart Bbbbbbb... - Emission Reduction and PM Concentration Requirements

Code of Federal Regulations, 2010 CFR

2010-07-01

... from equipment in target HAP service Route the process vent stream to a PM control device with:a. A PM percent reduction efficiency of 95 percent (98 percent for new sources), or b. An outlet concentration of...

ASSESSMENT OF BIOFILTER MEDIA PARTICLE SIZES FOR REMOVING AMMONIA

USDA-ARS?s Scientific Manuscript database

With increased concerns over odor and gas emissions from livestock production facilities more efficient technologies of air pollution control are needed to mitigate the deleterious effects of air contaminants. Gas-phase biofilters for treating contaminant gases from poultry and livestock operations ...

Assessment of Biofilter Media Particle Sizes for Removing Ammonia

USDA-ARS?s Scientific Manuscript database

With increased concerns over odor and gas emissions from livestock production facilities more efficient technologies of air pollution control are needed to mitigate the deleterious effects of air contaminants. Gas-phase biofilters for treating contaminant gases from poultry and livestock operations ...

DNA-length-dependent quenching of fluorescently labeled iron oxide nanoparticles with gold, graphene oxide and MoS2 nanostructures.

PubMed

Balcioglu, Mustafa; Rana, Muhit; Robertson, Neil; Yigit, Mehmet V

2014-08-13

We controlled the fluorescence emission of a fluorescently labeled iron oxide nanoparticle using three different nanomaterials with ultraefficient quenching capabilities. The control over the fluorescence emission was investigated via spacing introduced by the surface-functionalized single-stranded DNA molecules. DNA molecules were conjugated on different templates, either on the surface of the fluorescently labeled iron oxide nanoparticles or gold and nanographene oxide. The efficiency of the quenching was determined and compared with various fluorescently labeled iron oxide nanoparticle and nanoquencher combinations using DNA molecules with three different lengths. We have found that the template for DNA conjugation plays significant role on quenching the fluorescence emission of the fluorescently labeled iron oxide nanoparticles. We have observed that the size of the DNA controls the quenching efficiency when conjugated only on the fluorescently labeled iron oxide nanoparticles by setting a spacer between the surfaces and resulting change in the hydrodynamic size. The quenching efficiency with 12mer, 23mer and 36mer oligonucleotides decreased to 56%, 54% and 53% with gold nanoparticles, 58%, 38% and 32% with nanographene oxide, 46%, 38% and 35% with MoS2, respectively. On the other hand, the presence, not the size, of the DNA molecules on the other surfaces quenched the fluorescence significantly with different degrees. To understand the effect of the mobility of the DNA molecules on the nanoparticle surface, DNA molecules were attached to the surface with two different approaches. Covalently immobilized oligonucleotides decreased the quenching efficiency of nanographene oxide and gold nanoparticles to ∼22% and ∼21%, respectively, whereas noncovalently adsorbed oligonucleotides decreased it to ∼25% and ∼55%, respectively. As a result, we have found that each nanoquencher has a powerful quenching capability against a fluorescent nanoparticle, which can be tuned with surface functionalized DNA molecules.

Innovative Airbreathing Propulsion Concepts for Access to Space

NASA Technical Reports Server (NTRS)

Whitlow, Jr., Woodrow; Blech, Richard A.; Blankson, Isaiah M.

2001-01-01

This paper will present technologies and concepts for novel aeropropulsion systems. These technologies will enhance the safety of operations, reduce life cycle costs, and contribute to reduced costs of air travel and access to space. One of the goals of the NASA program is to reduce the carbon-dioxide emissions of aircraft engines. Engine concepts that use highly efficient fuel cell/electric drive technologies in hydrogen-fueled engines will be presented in the proposed paper. Carbon-dioxide emissions will be eliminated by replacing hydrocarbon fuel with hydrogen, and reduce NOx emissions through better combustion process control. A revolutionary exoskeletal engine concept, in which the engine drum is rotated, will be shown. This concept has the potential to allow a propulsion system that can be used for subsonic through hypersonic flight. Dual fan concepts that have ultra-high bypass ratios, low noise, and low drag will be presented. Flow-controlled turbofans and control-configured turbofans also will be discussed. To increase efficiency, a system of microengines distributed along lifting surfaces and on the fuselage is being investigated. This concept will be presented in the paper. Small propulsion systems for affordable, safe personal transportation vehicles will be discussed. These low-oil/oilless systems use technologies that enable significant cost and weight reductions. Pulse detonation engine-based hybrid-cycle and combined-cycle propulsion systems for aviation and space access will be presented.

40 CFR Table 4 of Subpart Bbbbbbb... - Continuous Compliance Demonstration Methods With the Emission Reduction and PM Concentration...

Code of Federal Regulations, 2012 CFR

2012-07-01

... compliance by * * * 1. Requirement to route all process vent streams from equipment in target HAP service to a PM control device with a PM percent reduction efficiency of 95 percent (98 percent for new sources... chemical preparations operation was in target HAP service. The control device monitoring data are averaged...

40 CFR Table 4 of Subpart Bbbbbbb... - Continuous Compliance Demonstration Methods With the Emission Reduction and PM Concentration...

Code of Federal Regulations, 2013 CFR

2013-07-01

... compliance by * * * 1. Requirement to route all process vent streams from equipment in target HAP service to a PM control device with a PM percent reduction efficiency of 95 percent (98 percent for new sources... chemical preparations operation was in target HAP service. The control device monitoring data are averaged...

40 CFR Table 4 of Subpart Bbbbbbb... - Continuous Compliance Demonstration Methods With the Emission Reduction and PM Concentration...

Code of Federal Regulations, 2014 CFR

2014-07-01

... compliance by * * * 1. Requirement to route all process vent streams from equipment in target HAP service to a PM control device with a PM percent reduction efficiency of 95 percent (98 percent for new sources... chemical preparations operation was in target HAP service. The control device monitoring data are averaged...

40 CFR Table 4 of Subpart Bbbbbbb... - Continuous Compliance Demonstration Methods With the Emission Reduction and PM Concentration...

Code of Federal Regulations, 2011 CFR

2011-07-01

... compliance by * * * 1. Requirement to route all process vent streams from equipment in target HAP service to a PM control device with a PM percent reduction efficiency of 95 percent (98 percent for new sources... chemical preparations operation was in target HAP service. The control device monitoring data are averaged...

Secondary electron emission characteristics of ion-textured copper and high-purity isotropic graphite surfaces

NASA Technical Reports Server (NTRS)

Curren, A. N.; Jensen, K. A.

1984-01-01

Experimentally determined values of true secondary electron emission and relative values of reflected primary electron yield for untreated and ion textured oxygen free high conductivity copper and untreated and ion textured high purity isotropic graphite surfaces are presented for a range of primary electron beam energies and beam impingement angles. This investigation was conducted to provide information that would improve the efficiency of multistage depressed collectors (MDC's) for microwave amplifier traveling wave tubes in space communications and aircraft applications. For high efficiency, MDC electrode surfaces must have low secondary electron emission characteristics. Although copper is a commonly used material for MDC electrodes, it exhibits relatively high levels of secondary electron emission if its surface is not treated for emission control. Recent studies demonstrated that high purity isotropic graphite is a promising material for MDC electrodes, particularly with ion textured surfaces. The materials were tested at primary electron beam energies of 200 to 2000 eV and at direct (0 deg) to near grazing (85 deg) beam impingement angles. True secondary electron emission and relative reflected primary electron yield characteristics of the ion textured surfaces were compared with each other and with those of untreated surfaces of the same materials. Both the untreated and ion textured graphite surfaces and the ion treated copper surface exhibited sharply reduced secondary electron emission characteristics relative to those of untreated copper. The ion treated graphite surface yielded the lowest emission levels.

Highly efficient exciplex formation via radical ion pair recombination in X-irradiated alkane solutions for luminophores with short fluorescence lifetimes.

PubMed

Melnikov, Anatoly R; Kalneus, Evgeny V; Korolev, Valeri V; Dranov, Igor G; Kruppa, Alexander I; Stass, Dmitri V

2014-08-01

X-irradiation of alkane solutions of N,N-dimethylaniline with various organic luminophores produces characteristic emission bands ascribed to the corresponding exciplexes. In contrast to optical generation, which requires diffusion-controlled quenching of excited states, an additional channel of exciplex formation via irreversible recombination of radical ion pairs is operative here, which produces exciplexes in solution with high efficiency even for p-terphenyl and diphenylacetylene having fluorescence decay times of 0.95 ns and 8 ps, respectively. The exciplex emission band is sensitive to an external magnetic field and exerts a very large observed magnetic field effect of up to 20%, the maximum possible value under the conditions of the described experiment.

A model-based gain scheduling approach for controlling the common-rail system for GDI engines

NASA Astrophysics Data System (ADS)

di Gaeta, Alessandro; Montanaro, Umberto; Fiengo, Giovanni; Palladino, Angelo; Giglio, Veniero

2012-04-01

The progressive reduction in vehicle emission requirements have forced the automotive industry to invest in research for developing alternative and more efficient control strategies. All control features and resources are permanently active in an electronic control unit (ECU), ensuring the best performance with respect to emissions, fuel economy, driveability and diagnostics, independently from engine working point. In this article, a considerable step forward has been achieved by the common-rail technology which has made possible to vary the injection pressure over the entire engine speed range. As a consequence, the injection of a fixed amount of fuel is more precise and multiple injections in a combustion cycle can be made. In this article, a novel gain scheduling pressure controller for gasoline direct injection (GDI) engine is designed to stabilise the mean fuel pressure into the rail and to track demanded pressure trajectories. By exploiting a simple control-oriented model describing the mean pressure dynamics in the rail, the control structure turns to be simple enough to be effectively implemented in commercial ECUs. Experimental results in a wide range of operating points confirm the effectiveness of the proposed control method to tame efficiently the mean value pressure dynamics of the plant showing a good accuracy and robustness with respect to unavoidable parameters uncertainties, unmodelled dynamics, and hidden coupling terms.

Efficient air pollution regulation of coal-fired power in China

NASA Astrophysics Data System (ADS)

Feng, Therese

This dissertation evaluates monetary external costs of electricity generation in the People's Republic of China and implications for efficient pollution control policy. It presents an integrated assessment of environmental damages of air emissions of a representative new coal-fired plant in urban areas of north and south China. The simulation evaluates the nature and magnitude of damages in China, transboundary effects in Japan and Korea, and global greenhouse gas warming impacts. The valuation is used to identify efficient abatement policy for Chinese plants over time; evaluate benefits of differentiated policies; and consider the importance of dynamic policy. Potential annual damages of operating a 600-MW power plant without controls in China today would be 43-45 million (U.S. 1995). Annual local damages of 37-40 million far exceed transboundary or greenhouse gas damages (1.4 million and $4.6 million respectively). The largest component of damages is the risk of human mortality and chronic morbidity from long-term exposure to fine particles. Efficient pollution control minimizes the sum of abatement costs and residual unabated damages. Because monetary damages reflect sufferers' willingness to pay to avoid environmental risks, the choice of efficient controls is fundamentally tied to societal values and preferences. The optimal path for Chinese abatement moves from modest dispersion measures at present to combined dispersion and emission controls approaching those of current-day United States, by 2050. The inclusion of transboundary and greenhouse damages does not substantively alter local policies. Welfare benefits are gained by differentiating abatement policy by pollutant, meteorological parameters, and by population density. An analysis of optimal one-time investment in abatement for a plant in a growing economy suggests that some investment is optimal at all incomes but no single level of abatement is suitable for all economies. Forward-looking policy anticipates higher future values for environmental services and provides distinct welfare advantages over time compared to myopic or static policies-such as the imposition of developed country standards-especially if aggregate capacity growth is considered.

Using an ultra-thin non-doped orange emission layer to realize high efficiency white organic light-emitting diodes with low efficiency roll-off

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu, Liping; Chen, Jiangshan; Ma, Dongge, E-mail: mdg1014@ciac.ac.cn

2014-06-28

By adopting an ultra-thin non-doped orange emission layer sandwiched between two blue emission layers, high efficiency white organic light-emitting diodes (WOLEDs) with reduced efficiency roll-off were fabricated. The optimized devices show a balanced white emission with Internationale de L'Eclairage of (0.41, 0.44) at the luminance of 1000 cd/m{sup 2}, and the maximum power efficiency, current efficiency (CE), and external quantum efficiency reach 63.2 lm/W, 59.3 cd/A, and 23.1%, which slightly shift to 53.4 lm/W, 57.1 cd/A, and 22.2% at 1000 cd/m{sup 2}, respectively, showing low efficiency roll-off. Detailed investigations on the recombination zone and the transient electroluminescence (EL) clearly reveal the EL processes of the ultra-thinmore » non-doped orange emission layer in WOLEDs.« less

Adiabatic passage in photon-echo quantum memories

NASA Astrophysics Data System (ADS)

Demeter, Gabor

2013-11-01

Photon-echo-based quantum memories use inhomogeneously broadened, optically thick ensembles of absorbers to store a weak optical signal and employ various protocols to rephase the atomic coherences for information retrieval. We study the application of two consecutive, frequency-chirped control pulses for coherence rephasing in an ensemble with a “natural” inhomogeneous broadening. Although propagation effects distort the two control pulses differently, chirped pulses that drive adiabatic passage can rephase atomic coherences in an optically thick storage medium. Combined with spatial phase-mismatching techniques to prevent primary echo emission, coherences can be rephased around the ground state to achieve secondary echo emission with close to unit efficiency. Potential advantages over similar schemes working with π pulses include greater potential signal fidelity, reduced noise due to spontaneous emission, and better capability for the storage of multiple memory channels.

In Situ Monitoring of RAFT Polymerization by Tetraphenylethylene-Containing Agents with Aggregation-Induced Emission Characteristics.

PubMed

Liu, Shunjie; Cheng, Yanhua; Zhang, Haoke; Qiu, Zijie; Kwok, Ryan T K; Lam, Jacky W Y; Tang, Ben Zhong

2018-05-22

A facile and efficient approach is demonstrated to visualize the polymerization in situ. A group of tetraphenylethylene (TPE)-containing dithiocarbamates were synthesized and screened as agents for reversible addition fragmentation chain transfer (RAFT) polymerizations. The spatial-temporal control characteristics of photochemistry enabled the RAFT polymerizations to be ON and OFF on demand under alternating visible light irradiation. The emission of TPE is sensitive to the local viscosity change owing to its aggregation-induced emission characteristic. Quantitative information could be easily acquired by the naked eye without destroying the reaction system. Furthermore, the versatility of such a technique was well demonstrated by 12 different polymerization systems. The present approach thus demonstrated a powerful platform for understanding the controlled living radical polymerization process. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Evaluating the effects of China's pollution control on inter-annual trends and uncertainties of atmospheric mercury emissions

NASA Astrophysics Data System (ADS)

Zhao, Y.; Zhong, H.; Zhang, J.; Nielsen, C. P.

2014-10-01

China's atmospheric mercury (Hg) emissions of anthropogenic origin have been effectively restrained through the national policy of air pollution control. Improved methods based on available field measurements are developed to quantify the benefits of Hg abatement through various emission control measures. Those measures include increased use of flue gas desulfurization (FGD) and selective catalyst reduction (SCR) systems for power sector, precalciners with fabric filter (FF) for cement production, machinery coking with electrostatic precipitator (ESP) for iron and steel production, and advanced manufacturing technologies for nonferrous metal smelting. Declining trends in emissions factors for those sources are revealed, leading to a much slower growth of national total Hg emissions than that of energy and economy, from 679 in 2005 to 750 metric tons (t) in 2012. In particular, nearly half of emissions from the above-mentioned four types of sources are expected to be reduced in 2012, attributed to expansion of technologies with high energy efficiencies and air pollutant removal rates after 2005. The speciation of Hg emissions keeps stable for recent years, with the mass fractions of around 55, 39 and 6% for Hg0, Hg2+ and Hgp, respectively. The lower estimate of Hg emissions than previous inventories is supported by limited chemistry simulation work, but middle-to-long term observation on ambient Hg levels is further needed to justify the inter-annual trends of estimated Hg emissions. With improved implementation of emission controls and energy saving, 23% reduction in annual Hg emissions for the most optimistic case in 2030 is expected compared to 2012, with total emissions below 600 t. While Hg emissions are evaluated to be gradually constrained, increased uncertainties are quantified with Monte-Carlo simulation for recent years, particularly for power and certain industrial sources. The uncertainty of Hg emissions from coal-fired power plants, as an example, increased from -48~ +73% in 2005 to -50~ +89% in 2012 (expressed as 95% confidence interval). This is attributed mainly to swiftly increased penetration of advanced manufacturing and pollutant control technologies. The unclear operation status or relatively small sample size of field measurements on those technologies results in lower but highly varied emission factors. To further confirm the benefits of pollution control polices with reduced uncertainty, therefore, systematic investigations are recommended specific for Hg pollution sources, and the variability of temporal trends and spatial distributions of Hg emissions need to be better tracked for the country under dramatic changes in economy, energy and air pollution status.

Photoexcited emission efficiencies of zinc oxide

NASA Astrophysics Data System (ADS)

Foreman, John Vincent

Optoelectronic properties of the II-VI semiconductor zinc oxide (ZnO) have been studied scientifically for almost 60 years; however, many fundamental questions remain unanswered about its two primary emission bands--the exciton-related luminescence in the ultraviolet and the defect-related emission band centered in the green portion of the visible spectrum. The work in this dissertation was motivated by the surprising optical properties of a ZnO nanowire sample grown by the group of Prof. Jie Liu, Department of Chemistry, Duke University. We found that this nanowire sample exhibited defect-related green/white emission of unprecedented intensity relative to near-band-edge luminescence. The experimental work comprising this dissertation was designed to explain the optical properties of this ZnO nanowire sample. Understanding the physics underlying such exceptional intensity of green emission addresses many of the open questions of ZnO research and assesses the possibility of using ZnO nanostructures as an ultraviolet-excited, broadband visible phosphor. The goal of this dissertation is to provide insight into what factors influence the radiative and nonradiative recombination efficiencies of ZnO by characterizing simultaneously the optical properties of the near-band-edge ultraviolet and the defect-related green emission bands. Specifically, we seek to understand the mechanisms of ultraviolet and green emission, the mechanism of energy transfer between them, and the evolution of their emission efficiencies with parameters such as excitation density and sample temperature. These fundamental but unanswered questions of ZnO emission are addressed here by using a novel combination of ultrafast spectroscopic techniques in conjunction with a systematic set of ZnO samples. Through this systematic investigation, ZnO may be realistically assessed as a potential green/white light phosphor. Photoluminescence techniques are used to characterize the thermal quenching behavior of both emission bands in micrometer-scale ZnO powders. Green luminescence quenching is described by activation energies associated with bound excitons. We find that green luminescence efficiency is maximized when excitons are localized in the vicinity of green-emitting defects. Subsequent photoluminescence excitation measurements performed at multiple temperatures independently verified that green band photoluminescence intensity directly correlates with the photogenerated exciton population. The spatial distributions of green-emitting defects and nonradiative traps are elucidated by an innovative combination of quantum efficiency and time-integrated/resolved photoluminescence measurements. By combining these techniques for the first time, we take advantage of the drastically different absorption coefficients for one- and two-photon excitations to provide details about the types and concentrations of surface and bulk defects and to demonstrate the non-negligible effects of reabsorption. A comparison of results for unannealed and annealed ZnO powders indicates that the annealing process creates a high density of green-emitting defects near the surface of the sample while simultaneously reducing the density of bulk nonradiative traps. These experimental results are discussed in the context of a simple rate equation model that accounts for the quantum efficiencies of both emission bands. For both femtosecond pulsed and continuous-wave excitations, the green band efficiency is found to decrease with increasing excitation density--from 35% to 5% for pulsed excitation spanning 1-1000 muJ/cm--2, and from 60% to 5% for continuous excitation in the range 0.01-10 W/cm --2. On the other hand, near-band-edge emission efficiency increases from 0.4% to 25% for increasing pulsed excitation density and from 0.1% to 0.6% for continuous excitation. It is shown experimentally that these changes in efficiency correspond to a reduction in exciton formation efficiency. The differences in efficiencies for pulsed versus continuous-wave excitation are described by changes in the relative rates of exciton luminescence and exciton capture at green defects based on an extended rate equation model that accounts for the excitation density dependence of both luminescence bands. In using a systematic set of ZnO samples and a novel combination of optical techniques to characterize them, this body of work presents a comprehensive and detailed physical picture of recombination mechanisms in ZnO. The insight provided by these results has immediate implications for material growth/processing techniques and should help material growers control the relative efficiencies of ultraviolet, green/visible, and nonradiative recombination channels in ZnO.

Aerial Sampling of Emissions from Biomass Pile Burns in ...

EPA Pesticide Factsheets

Abstract (already cleared). Emissions from burning piles of post-harvest timber slash in Grande Ronde, Oregon were sampled using an instrument platform lofted into the plume using a tether-controlled aerostat or balloon. Emissions of carbon monoxide, carbon dioxide, methane, particulate matter (PM2.5 µm), black carbon, ultraviolet absorbing PM, elemental/organic carbon, semi-volatile organics (polycyclic aromatic hydrocarbons and polychlorinated dibenzodioxins/dibenzofurans), filter-based metals, and volatile organics were sampled for determination of emission factors. The effect on emissions from covering or not covering piles with polyethylene sheets to prevent fuel wetting was determined. Results showed that the uncovered (“wet”) piles burned with lower combustion efficiency and higher emissions of volatile organic compounds. Results for other pollutants will also be discussed. This work determines the first known in-field emission factors for burning of timber slash piles. The results also document the effect on emissions of covering the piles with polyethylene covers to reduce the moisture content of the biomass.

Electric Field Induce Blue Shift and Intensity Enhancement in 2D Exciplex Organic Light Emitting Diodes; Controlling Electron-Hole Separation.

PubMed

Al Attar, Hameed A; Monkman, Andy P

2016-09-01

A simple but novel method is designed to study the characteristics of the exciplex state pinned at a donor-acceptor abrupt interface and the effect an external electric field has on these excited states. The reverse Onsager process, where the field induces blue-shifted emission and increases the efficiency of the exciplex emission as the e-h separation reduces, is discussed. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Urban air chemistry and diesel vehicles emissions: Quantifying small and big hydrocarbons by CIMS to improve emission inventories

NASA Astrophysics Data System (ADS)

Jobson, B. T.; Derstroff, B.; Edtbauer, A.; VanderSchelden, G. S.; Williams, J.

2017-10-01

Emissions from vehicles are a major source of volatile organic compounds (VOCs) in urban environments. Photochemical oxidation of VOCs emitted from vehicle exhaust contributes to O3 and PM2.5 formation, harmful pollutants that major urban areas struggle to control. How will a shift to a diesel engine fleet impact urban air chemistry? Diesel vehicles are a growing fraction of the passenger vehicle fleet in Europe as a result of a deliberate policy to reduce energy consumption and CO2 emissions from the transportation sector (Sullivan et al., 2004). In countries such as France the diesel passenger fleet was already ∼50% of the total in 2009, up from 20% in 1995. Dunmore et al. (2015) have recently inferred that in London, HO radical loss rates to organic compounds is dominated by diesel engine emissions. In the US, increasingly more stringent vehicles emission standards and requirement for improved energy efficiency means spark ignition passenger vehicle emissions have declined significantly over the last 20 years, resulting in the urban diesel fleet traffic (freight trucks) having a growing importance as a source of vehicle pollution (McDonald et al., 2013). The recent scandal involving a major car manufacturer rigging emission controls for diesel passenger cars is a reminder that real world emissions of VOCs from diesel engines are not well understood nor thoroughly accounted for in air quality modeling.

Lean, premixed, prevaporized fuel combustor conceptual design study

NASA Technical Reports Server (NTRS)

Fiorentino, A. J.; Greene, W.; Kim, J.

1979-01-01

Four combustor concepts, designed for the energy efficient engine, utilize variable geometry or other flow modulation techniques to control the equivalence ratio of the initial burning zone. Lean conditions are maintained at high power to control oxides of nitrogen while near stoichometric conditions are maintained at low power for low CO and THC emissions. Each concept was analyzed and ranked for its potential in meeting the goals of the program. Although the primary goal of the program is a low level of nitric oxide emissions at stratospheric cruise conditions, both the ground level EPA emission standards and combustor performance and operational requirements typical of advanced subsonic aircraft engines are retained as goals as well. Based on the analytical projections made, two of the concepts offer the potential of achieving the emission goals; however, the projected operational characteristics and reliability of any concept to perform satisfactorily over an entire aircraft flight envelope would require extensive experimental substantiation before engine adaptation can be considered.

Fast Adaptive Thermal Camouflage Based on Flexible VO₂/Graphene/CNT Thin Films.

PubMed

Xiao, Lin; Ma, He; Liu, Junku; Zhao, Wei; Jia, Yi; Zhao, Qiang; Liu, Kai; Wu, Yang; Wei, Yang; Fan, Shoushan; Jiang, Kaili

2015-12-09

Adaptive camouflage in thermal imaging, a form of cloaking technology capable of blending naturally into the surrounding environment, has been a great challenge in the past decades. Emissivity engineering for thermal camouflage is regarded as a more promising way compared to merely temperature controlling that has to dissipate a large amount of excessive heat. However, practical devices with an active modulation of emissivity have yet to be well explored. In this letter we demonstrate an active cloaking device capable of efficient thermal radiance control, which consists of a vanadium dioxide (VO2) layer, with a negative differential thermal emissivity, coated on a graphene/carbon nanotube (CNT) thin film. A slight joule heating drastically changes the emissivity of the device, achieving rapid switchable thermal camouflage with a low power consumption and excellent reliability. It is believed that this device will find wide applications not only in artificial systems for infrared camouflage or cloaking but also in energy-saving smart windows and thermo-optical modulators.

Reactivity-based industrial volatile organic compounds emission inventory and its implications for ozone control strategies in China

NASA Astrophysics Data System (ADS)

Liang, Xiaoming; Chen, Xiaofang; Zhang, Jiani; Shi, Tianli; Sun, Xibo; Fan, Liya; Wang, Liming; Ye, Daiqi

2017-08-01

Increasingly serious ozone (O3) pollution, along with decreasing NOx emission, is creating a big challenge in the control of volatile organic compounds (VOCs) in China. More efficient and effective measures are assuredly needed for controlling VOCs. In this study, a reactivity-based industrial VOCs emission inventory was established in China based on the concept of ozone formation potential (OFP). Key VOCs species, major VOCs sources, and dominant regions with high reactivity were identified. Our results show that the top 15 OFP-based species, including m/p-xylene, toluene, propene, o-xylene, and ethyl benzene, contribute 69% of the total OFP but only 30% of the total emission. The architectural decoration industry, oil refinery industry, storage and transport, and seven other sources constituted the top 10 OFP subsectors, together contributing a total of 85%. The provincial and spatial characteristics of OFP are generally consistent with those of mass-based inventory. The implications for O3 control strategies in China are discussed. We propose a reactivity-based national definition of VOCs and low-reactive substitution strategies, combined with evaluations of health risks. Priority should be given to the top 15 or more species with high reactivity through their major emission sources. Reactivity-based policies should be flexibly applied for O3 mitigation based on the sensitivity of O3 formation conditions.

Emissions inventory and scenario analyses of air pollutants in Guangdong Province, China

NASA Astrophysics Data System (ADS)

Chen, Hui; Meng, Jing

2017-03-01

Air pollution, causing significantly adverse health impacts and severe environmental problems, has raised great concerns in China in the past few decades. Guangdong Province faces major challenges to address the regional air pollution problem due to the lack of an emissions inventory. To fill this gap, an emissions inventory of primary fine particles (PM2.5) is compiled for the year 2012, and the key precursors (sulfur dioxide, nitrogen oxides) are identified. Furthermore, policy packages are simulated during the period of 2012‒2030 to investigate the potential mitigation effect. The results show that in 2012, SO2, NO x , and PM2.5 emissions in Guangdong Province were as high as (951.7, 1363.6, and 294.9) kt, respectively. Industrial production processes are the largest source of SO2 and PM2.5 emissions, and transport is the top contributor of NO x emissions. Both the baseline scenario and policy scenario are constructed based on projected energy growth and policy designs. Under the baseline scenario, SO2, NO x , and PM2.5 emissions will almost double in 2030 without proper emissions control policies. The suggested policies are categorized into end-of- pipe control in power plants (ECP), end-of-pipe control in industrial processes (ECI), fuel improvement (FI), energy efficiency improvement (EEI), substitution-pattern development (SPD), and energy saving options (ESO). With the implementation of all these policies, SO2, NO x , and PM2.5 emissions are projected to drop to (303.1, 585.4, and 102.4) kt, respectively, in 2030. This inventory and simulated results will provide deeper insights for policy makers to understand the present situation and the evolution of key emissions in Guangdong Province.

Metal-enhanced fluorescence exciplex emission.

PubMed

Zhang, Yongxia; Mali, Buddha L; Geddes, Chris D

2012-01-01

In this letter, we report the first observation of metal-enhanced exciplex fluorescence, observed from anthracene in the presence of diethylaniline. Anthracene in the presence of diethylaniline in close proximity to Silver Island Films (SIFs) shows enhanced monomer and exciplex emission as compared to a non-silvered control sample containing no silver nanoparticles. Our findings suggest two complementary methods for the enhancement: (i) surface plasmons can radiate coupled monomer and exciplex fluorescence efficiently, and (ii) enhanced absorption (enhanced electric near-field) further facilitates enhanced emission. Our exciplex studies help us to further understand the complex photophysics of the metal-enhanced fluorescence technology. Copyright © 2011 Elsevier B.V. All rights reserved.

134Cs emission probabilities determination by gamma spectrometry

NASA Astrophysics Data System (ADS)

de Almeida, M. C. M.; Poledna, R.; Delgado, J. U.; Silva, R. L.; Araujo, M. T. F.; da Silva, C. J.

2018-03-01

The National Laboratory for Ionizing Radiation Metrology (LNMRI/IRD/CNEN) of Rio de Janeiro performed primary and secondary standardization of different radionuclides reaching satisfactory uncertainties. A solution of 134Cs radionuclide was purchased from commercial supplier to emission probabilities determination of some of its energies. 134Cs is a beta gamma emitter with 754 days of half-life. This radionuclide is used as standard in environmental, water and food control. It is also important to germanium detector calibration. The gamma emission probabilities (Pγ) were determined mainly for some energies of the 134Cs by efficiency curve method and the Pγ absolute uncertainties obtained were below 1% (k=1).

Integrated thermal and energy management of plug-in hybrid electric vehicles

NASA Astrophysics Data System (ADS)

Shams-Zahraei, Mojtaba; Kouzani, Abbas Z.; Kutter, Steffen; Bäker, Bernard

2012-10-01

In plug-in hybrid electric vehicles (PHEVs), the engine temperature declines due to reduced engine load and extended engine off period. It is proven that the engine efficiency and emissions depend on the engine temperature. Also, temperature influences the vehicle air-conditioner and the cabin heater loads. Particularly, while the engine is cold, the power demand of the cabin heater needs to be provided by the batteries instead of the waste heat of engine coolant. The existing energy management strategies (EMS) of PHEVs focus on the improvement of fuel efficiency based on hot engine characteristics neglecting the effect of temperature on the engine performance and the vehicle power demand. This paper presents a new EMS incorporating an engine thermal management method which derives the global optimal battery charge depletion trajectories. A dynamic programming-based algorithm is developed to enforce the charge depletion boundaries, while optimizing a fuel consumption cost function by controlling the engine power. The optimal control problem formulates the cost function based on two state variables: battery charge and engine internal temperature. Simulation results demonstrate that temperature and the cabin heater/air-conditioner power demand can significantly influence the optimal solution for the EMS, and accordingly fuel efficiency and emissions of PHEVs.

Effects of Aftermarket Control Technologies on Gas and Particle Phase Oxidative Potential from Diesel Engine Emissions.

PubMed

Pavlovic, Jelica; Holder, Amara L; Yelverton, Tiffany L B

2015-09-01

Particulate matter (PM) originating from diesel combustion is a public health concern due to its association with adverse effects on respiratory and cardiovascular diseases and lung cancer. This study investigated emissions from three stationary diesel engines (gensets) and varying power output (230 kW, 400 kW, and 600 kW) at 50% and 90% load to determine concentrations of gaseous (GROS) and PM reactive oxygen species (PMROS). In addition, the influence of three modern emission control technologies on ROS emissions was evaluated: active and passive diesel particulate filters (A-DPF and P-DPF) and a diesel oxidation catalyst (DOC). PMROS made up 30-50% of the total ROS measured without aftermarket controls. All applied controls removed PMROS by more than 75% on average. However, the oxidative potential of PM downstream of these devices was not diminished at the same rate and particles surviving the A-PDF had an even higher oxidative potential on a per PM mass basis compared to the particles emitted by uncontrolled gensets. Further, the GROS as compared to PMROS emissions were not reduced with the same efficiency (<36%). GROS concentrations were highest with the DOC in use, indicating continued formation of GROS with this control. Correlation analyses showed that PMROS and to a lesser extent GROS have a good correlation with semivolatile organic carbon (OC1) subfraction. In addition, results suggest that chemical composition, rather than PM size, is responsible for differences in the PM oxidative potential.

An intelligent remote control system for ECEI on EAST

NASA Astrophysics Data System (ADS)

Chen, Dongxu; Zhu, Yilun; Zhao, Zhenling; Qu, Chengming; Liao, Wang; Xie, Jinlin; Liu, Wandong

2017-08-01

An intelligent remote control system based on a power distribution unit (PDU) and Arduino has been designed for the electron cyclotron emission imaging (ECEI) system on Experimental Advanced Superconducting Tokamak (EAST). This intelligent system has three major functions: ECEI system reboot, measurement region adjustment and signal amplitude optimization. The observation region of ECEI can be modified for different physics proposals by remotely tuning the optical and electronics systems. Via the remote adjustment of the attenuation level, the ECEI intermediate frequency signal amplitude can be efficiently optimized. The remote control system provides a feasible and reliable solution for the improvement of signal quality and the efficiency of the ECEI diagnostic system, which is also valuable for other diagnostic systems.

Photochemical grid model implementation and application of VOC, NOx, and O3 source apportionment

EPA Science Inventory

For the purposes of developing optimal emissions control strategies, efficient approaches are needed to identify the major sources or groups of sources that contribute to elevated ozone (O3) concentrations. Source-based apportionment techniques implemented in photochemical grid m...

Single-shot velocity-map imaging of attosecond light-field control at kilohertz rate.

PubMed

Süssmann, F; Zherebtsov, S; Plenge, J; Johnson, Nora G; Kübel, M; Sayler, A M; Mondes, V; Graf, C; Rühl, E; Paulus, G G; Schmischke, D; Swrschek, P; Kling, M F

2011-09-01

High-speed, single-shot velocity-map imaging (VMI) is combined with carrier-envelope phase (CEP) tagging by a single-shot stereographic above-threshold ionization (ATI) phase-meter. The experimental setup provides a versatile tool for angle-resolved studies of the attosecond control of electrons in atoms, molecules, and nanostructures. Single-shot VMI at kHz repetition rate is realized with a highly sensitive megapixel complementary metal-oxide semiconductor camera omitting the need for additional image intensifiers. The developed camera software allows for efficient background suppression and the storage of up to 1024 events for each image in real time. The approach is demonstrated by measuring the CEP-dependence of the electron emission from ATI of Xe in strong (≈10(13) W/cm(2)) near single-cycle (4 fs) laser fields. Efficient background signal suppression with the system is illustrated for the electron emission from SiO(2) nanospheres. © 2011 American Institute of Physics

High-efficiency tris(8-hydroxyquinoline)aluminum (Alq3) complexes for organic white-light-emitting diodes and solid-state lighting.

PubMed

Pérez-Bolívar, César; Takizawa, Shin-ya; Nishimura, Go; Montes, Victor A; Anzenbacher, Pavel

2011-08-08

Combinations of electron-withdrawing and -donating substituents on the 8-hydroxyquinoline ligand of the tris(8-hydroxyquinoline)aluminum (Alq(3)) complexes allow for control of the HOMO and LUMO energies and the HOMO-LUMO gap responsible for emission from the complexes. Here, we present a systematic study on tuning the emission and electroluminescence (EL) from Alq(3) complexes from the green to blue region. In this study, we explored the combination of electron-donating substituents on C4 and C6. Compounds 1-6 displayed the emission tuning between 478 and 526 nm, and fluorescence quantum yield between 0.15 and 0.57. The compounds 2-6 were used as emitters and hosts in organic light-emitting diodes (OLEDs). The highest OLED external quantum efficiency (EQE) observed was 4.6%, which is among the highest observed for Alq(3) complexes. Also, the compounds 3-5 were used as hosts for red phosphorescent dopants to obtain white light-emitting diodes (WOLED). The WOLEDs displayed high efficiency (EQE up to 19%) and high white color purity (color rendering index (CRI≈85). Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Exploring sub-daily to seasonal variations in methane exchange in a single-crop rice paddy in central Japan

NASA Astrophysics Data System (ADS)

Iwata, Hiroki; Mano, Masayoshi; Ono, Keisuke; Tokida, Takeshi; Kawazoe, Takahiro; Kosugi, Yoshiko; Sakabe, Ayaka; Takahashi, Kenshi; Miyata, Akira

2018-04-01

Season-long methane (CH4) exchange was observed in a rice paddy field in central Japan (Kanto Region) using the eddy covariance technique to clarify the variations in environmental controls on CH4 exchange in different stages of cultivation. Before heading of rice plant, the CH4 emission depended on wind speed and soil temperature. The soil temperature dependence can be due to an increase in CH4 production, higher molecular diffusion, and higher conductance within rice plant at higher soil temperature. An occurrence of ebullitive emission was also suggested from the wind speed dependence. After heading was completed, relative humidity and water temperature influenced CH4 emission. The amplitude of the diurnal variation in emission increased from 0.03 μmolm-2s-1 in the late pre-heading stage to 0.13 μmolm-2s-1 in the post-heading stage. Induced convective throughflow within the rice aerenchyma after the change in plant structure was attributable to this variation in environmental controls after the heading. After drainage, CH4 emission was confined to short periods after strong rain events. The water level controlled the timing of emission, most likely by influencing the diffusion efficiency from the anoxic soil to the atmosphere and CH4 oxidation in the surface oxic zone. The variation in the dominant transport pathway needs to be accounted for in terrestrial ecosystem models to accurately predict CH4 emission from rice paddies.

The future of emissions trading in light of the acid rain experience

DOE Office of Scientific and Technical Information (OSTI.GOV)

McLean, B.J.; Rico, R.

1995-12-31

The idea of emissions trading was developed more than two decades ago by environmental economists eager to provide new ideas for how to improve the efficiency of environmental protection. However, early emissions trading efforts were built on the historical {open_quotes}command and control{close_quotes} infrastructure which has dominated U.S. environmental protection until today. The {open_quotes}command and control{close_quotes} model initially had advantages that were of a very pragmatic character: it assured large pollution reductions in a time when large, cheap reductions were available and necessary; and it did not require a sophisticated government infrastructure. Within the last five years, large-scale emission trading programsmore » have been successfully designed and started that are fundamentally different from the earlier efforts, creating a new paradigm for environmental control just when our understanding of environmental problems is changing as well. The purpose of this paper is to focus on the largest national-scale program--the Acid Rain Program--and from that experience, forecast when emission trading programs may be headed based on our understanding of the factors currently influencing environmental management. The first section of this paper will briefly review the history of emissions trading programs, followed by a summary of the features of the Acid Rain Program, highlighting those features that distinguish it from previous efforts. The last section addresses the opportunities for emissions trading (and its probable future directions).« less

[Environmental efficiency evaluation under carbon emission constraint in Western China].

PubMed

Rong, Jian-bo; Yan, Li-jiao; Huang, Shao-rong; Zhang, Ge

2015-06-01

This research used the SBM model based on undesirable outputs to measure the static environmental efficiency of Western China under carbon emission constraint from 2000 to 2012. The researchers also utilized the Malmquist index to further analyze the change tendency of environmental efficiency. Additionally, Tobit regression analysis was used to study the factors relevant to environmental efficiency. Practical solutions to improve environmental quality in Western China were put forward. The study showed that in Western China, environmental efficiency with carbon emission constraint was significantly lower than that without carbon emission constraint, and the difference could be described as an inverse U-shaped curve which increased at first and then decreased. Guang-xi and Inner Mongolia, the two provinces met the effective environmental efficiency levels all the time under carbon emission constraint. However, the five provinces of Guizhou, Gansu, Qinghai, Ningxia and Xinjiang did not. Furthermore, Ningxia had the lowest level of environmental efficiency, with a score between 0.281-0.386. Although the environmental efficiency of most provinces was currently at an ineffective level, the environmental efficiency quality was gradually improving at an average speed of 6.6%. Excessive CO2 emission and a large amount of energy consumption were the primary factors causing environmental inefficiency in Western China, and energy intensity had the most negative impact on the environmental efficiency. The increase of import and export trade reduced the environmental efficiency significantly in Western China, while the increase of foreign direct investment had a positive effect on its environmental efficiency.

Using surface water application to reduce 1,3-dichloropropene emission from soil fumigation.

PubMed

Gao, Suduan; Trout, Thomas J

2006-01-01

High emissions from soil fumigants increase the risk of detrimental impact on workers, bystanders, and the environment, and jeopardize future availability of fumigants. Efficient and cost-effective approaches to minimize emissions are needed. This study evaluated the potential of surface water application (or water seal) to reduce 1,3-dichloropropene (1,3-D) emissions from soil (Hanford sandy loam) columns. Treatments included dry soil (control), initial water application (8 mm of water just before fumigant application), initial plus a second water application (2.6 mm) at 12 h, initial plus two water applications (2.6 mm each time) at 12 and 24 h, standard high density polyethylene (HDPE) tarp, initial water application plus HDPE tarp, and virtually impermeable film (VIF) tarp. Emissions from the soil surface and distribution of 1,3-D in the soil-gas phase were monitored for 2 wk. Each water application abruptly reduced 1,3-D emission flux, which rebounded over a few hours. Peak emission rates were substantially reduced, but total emission reduction was small. Total fumigant emission was 51% of applied for the control, 46% for initial water application only, and 41% for the three intermittent water applications with the remaining water treatment intermediate. The HDPE tarp alone resulted in 45% emission, while initial water application plus HDPE tarp resulted in 38% emission. The most effective soil surface treatment was VIF tarp (10% emission). Surface water application can be as effective, and less expensive than, standard HDPE tarp. Frequent water application is required to substantially reduce emissions.

Automated standardization technique for an inductively-coupled plasma emission spectrometer

USGS Publications Warehouse

Garbarino, John R.; Taylor, Howard E.

1982-01-01

The manifold assembly subsystem described permits real-time computer-controlled standardization and quality control of a commercial inductively-coupled plasma atomic emission spectrometer. The manifold assembly consists of a branch-structured glass manifold, a series of microcomputer-controlled solenoid valves, and a reservoir for each standard. Automated standardization involves selective actuation of each solenoid valve that permits a specific mixed standard solution to be pumped to the nebulizer of the spectrometer. Quality control is based on the evaluation of results obtained for a mixed standard containing 17 analytes, that is measured periodically with unknown samples. An inaccurate standard evaluation triggers restandardization of the instrument according to a predetermined protocol. Interaction of the computer-controlled manifold assembly hardware with the spectrometer system is outlined. Evaluation of the automated standardization system with respect to reliability, simplicity, flexibility, and efficiency is compared to the manual procedure. ?? 1982.

Benefits of China's efforts in gaseous pollutant control indicated by the bottom-up emissions and satellite observations 2000-2014

NASA Astrophysics Data System (ADS)

Xia, Yinmin; Zhao, Yu; Nielsen, Chris P.

2016-07-01

To evaluate the effectiveness of national air pollution control policies, the emissions of SO2, NOX, CO and CO2 in China are estimated using bottom-up methods for the most recent 15-year period (2000-2014). Vertical column densities (VCDs) from satellite observations are used to test the temporal and spatial patterns of emissions and to explore the ambient levels of gaseous pollutants across the country. The inter-annual trends in emissions and VCDs match well except for SO2. Such comparison is improved with an optimistic assumption in emission estimation that the emission standards for given industrial sources issued after 2010 have been fully enforced. Underestimation of emission abatement and enhanced atmospheric oxidization likely contribute to the discrepancy between SO2 emissions and VCDs. As suggested by VCDs and emissions estimated under the assumption of full implementation of emission standards, the control of SO2 in the 12th Five-Year Plan period (12th FYP, 2011-2015) is estimated to be more effective than that in the 11th FYP period (2006-2010), attributed to improved use of flue gas desulfurization in the power sector and implementation of new emission standards in key industrial sources. The opposite was true for CO, as energy efficiency improved more significantly from 2005 to 2010 due to closures of small industrial plants. Iron & steel production is estimated to have had particularly strong influence on temporal and spatial patterns of CO. In contrast to fast growth before 2011 driven by increased coal consumption and limited controls, NOX emissions decreased from 2011 to 2014 due to the penetration of selective catalytic/non-catalytic reduction systems in the power sector. This led to reduced NO2 VCDs, particularly in relatively highly polluted areas such as the eastern China and Pearl River Delta regions. In developed areas, transportation is playing an increasingly important role in air pollution, as suggested by the increased ratio of NO2 to SO2 VCDs. For air quality in mega cities, the inter-annual trends in emissions and VCDs indicate that surrounding areas are more influential in NO2 level for Beijing than those for Shanghai.

Detection of critical PM2.5 emission sources and their contributions to a heavy haze episode in Beijing, China, using an adjoint model

NASA Astrophysics Data System (ADS)

Zhai, Shixian; An, Xingqin; Zhao, Tianliang; Sun, Zhaobin; Wang, Wei; Hou, Qing; Guo, Zengyuan; Wang, Chao

2018-05-01

Air pollution sources and their regional transport are important issues for air quality control. The Global-Regional Assimilation and Prediction System coupled with the China Meteorological Administration Unified Atmospheric Chemistry Environment (GRAPES-CUACE) aerosol adjoint model was applied to detect the sensitive primary emission sources of a haze episode in Beijing occurring between 19 and 21 November 2012. The high PM2.5 concentration peaks occurring at 05:00 and 23:00 LT (GMT+8) over Beijing on 21 November 2012 were set as the cost functions for the aerosol adjoint model. The critical emission regions of the first PM2.5 concentration peak were tracked to the west and south of Beijing, with 2 to 3 days of cumulative transport of air pollutants to Beijing. The critical emission regions of the second peak were mainly located to the south of Beijing, where southeasterly moist air transport led to the hygroscopic growth of particles and pollutant convergence in front of the Taihang Mountains during the daytime on 21 November. The temporal variations in the sensitivity coefficients for the two PM2.5 concentration peaks revealed that the response time of the onset of Beijing haze pollution from the local primary emissions is approximately 1-2 h and that from the surrounding primary emissions it is approximately 7-12 h. The upstream Hebei province has the largest impact on the two PM2.5 concentration peaks, and the contribution of emissions from Hebei province to the first PM2.5 concentration peak (43.6 %) is greater than that to the second PM2.5 concentration peak (41.5 %). The second most influential province for the 05:00 LT PM2.5 concentration peak is Beijing (31.2 %), followed by Shanxi (9.8 %), Tianjin (9.8 %), and Shandong (5.7 %). The second most influential province for the 23:00 LT PM2.5 concentration peak is Beijing (35.7 %), followed by Shanxi (8.1 %), Shandong (8.0 %), and Tianjin (6.7 %). The adjoint model results were compared with the forward sensitivity simulations of the Models-3/CMAQ system. The two modeling approaches are highly comparable in their assessments of atmospheric pollution control schemes for critical emission regions, but the adjoint method has higher computational efficiency than the forward sensitivity method. The results also imply that critical regional emission reduction could be more efficient than individual peak emission control for improving regional PM2.5 air quality.

Diesel Combustion and Emission Using High Boost and High Injection Pressure in a Single Cylinder Engine

NASA Astrophysics Data System (ADS)

Aoyagi, Yuzo; Kunishima, Eiji; Asaumi, Yasuo; Aihara, Yoshiaki; Odaka, Matsuo; Goto, Yuichi

Heavy-duty diesel engines have adopted numerous technologies for clean emissions and low fuel consumption. Some are direct fuel injection combined with high injection pressure and adequate in-cylinder air motion, turbo-intercooler systems, and strong steel pistons. Using these technologies, diesel engines have achieved an extremely low CO2 emission as a prime mover. However, heavy-duty diesel engines with even lower NOx and PM emission levels are anticipated. This study achieved high-boost and lean diesel combustion using a single cylinder engine that provides good engine performance and clean exhaust emission. The experiment was done under conditions of intake air quantity up to five times that of a naturally aspirated (NA) engine and 200MPa injection pressure. The adopted pressure booster is an external supercharger that can control intake air temperature. In this engine, the maximum cylinder pressure was increased and new technologies were adopted, including a monotherm piston for endurance of Pmax =30MPa. Moreover, every engine part is newly designed. As the boost pressure increases, the rate of heat release resembles the injection rate and becomes sharper. The combustion and brake thermal efficiency are improved. This high boost and lean diesel combustion creates little smoke; ISCO and ISTHC without the ISNOx increase. It also yields good thermal efficiency.

Carbon dioxide efficiency of terrestrial enhanced weathering.

PubMed

Moosdorf, Nils; Renforth, Phil; Hartmann, Jens

2014-05-06

Terrestrial enhanced weathering, the spreading of ultramafic silicate rock flour to enhance natural weathering rates, has been suggested as part of a strategy to reduce global atmospheric CO2 levels. We budget potential CO2 sequestration against associated CO2 emissions to assess the net CO2 removal of terrestrial enhanced weathering. We combine global spatial data sets of potential source rocks, transport networks, and application areas with associated CO2 emissions in optimistic and pessimistic scenarios. The results show that the choice of source rocks and material comminution technique dominate the CO2 efficiency of enhanced weathering. CO2 emissions from transport amount to on average 0.5-3% of potentially sequestered CO2. The emissions of material mining and application are negligible. After accounting for all emissions, 0.5-1.0 t CO2 can be sequestered on average per tonne of rock, translating into a unit cost from 1.6 to 9.9 GJ per tonne CO2 sequestered by enhanced weathering. However, to control or reduce atmospheric CO2 concentrations substantially with enhanced weathering would require very large amounts of rock. Before enhanced weathering could be applied on large scales, more research is needed to assess weathering rates, potential side effects, social acceptability, and mechanisms of governance.

Tuning of the emission color of organic light emitting diodes via smartly designed aluminum plasmonics

NASA Astrophysics Data System (ADS)

Auer-Berger, Manuel; Tretnak, Veronika; Wenzl, Franz-Peter; Krenn, Joachim; List-Kratochvil, Emil J. W.

2017-02-01

With the invention of phosphorescent emitter material, organic light emitting diodes with internal quantum yields of up to 100% can be realized. Still, the extraction of the light from the OLED stack is a bottleneck, which hampers the availability of OLEDs with large external quantum efficiencies. In this contribution, we highlight the advantages of integrating aluminum nanodisc arrays into the OLED stack. By this, not only the out-coupling of light can be enhanced, but also the emission color can be tailored and controlled. By means of extinction- and fluorescence spectroscopy measurements we are able to show how the sharp features observed in the extinction measurements correlate with a very selective fluorescence enhancement of the organic emitter materials used in these studies. At the same time, localized surface plasmon resonances of the individual nanodiscs further modify the emission spectrum, e.g., by filtering the green emission tail. A combination of these factors leads to a modification of the emission color in between CIE1931 (x,y) chromaticity coordinates of (0.149, 0.225) and (0.152, 0.352). After accounting for the sensitivity of the human eye, we are able to demonstrate that this adjustment of the chromaticity coordinates goes is accompanied by an increase in device efficiency.

Fluidized-bed combustion reduces atmospheric pollutants

NASA Technical Reports Server (NTRS)

Jonke, A. A.

1972-01-01

Method of reducing sulfur and nitrogen oxides released during combustion of fossil fuels is described. Fuel is burned in fluidized bed of solids with simultaneous feeding of crushed or pulverized limestone to control emission. Process also offers high heat transfer rates and efficient contacting for gas-solid reactions.

NOVEL OXIDANT FOR ELEMENTAL MERCURY CONTROL FROM FLUE GAS

EPA Science Inventory

The primary objective of this study is to develop and test advanced noncarbonaceous solid sorbent materials suitable for removing the elemental form of mercury from power plant emissions. An efficient and cost-effective novel Hg(0) oxidant was evaluated in a lab-scale fixed-bed ...

Intelligent transportation systems for improving traffic energy efficiency and reducing GHG emissions from roadways : a white paper from the National Center for Sustainable Transportation.

DOT National Transportation Integrated Search

2015-11-01

The field of Intelligent Transportation Systems (ITS) has : witnessed significantly increased activity in recent years, : with the application of modern control, communications, : and information technologies to vehicles and roadway : infrastructure....

Effects of curcumin and ursolic acid on the mitochondrial coupling efficiency and hydrogen peroxide emission of intact skeletal myoblasts.

PubMed

Tueller, Daniel J; Harley, Jackson S; Hancock, Chad R

2017-10-21

Curcumin may improve blood glucose management, but the mechanism is not fully established. We demonstrated that curcumin (40 μM) reduced the mitochondrial coupling efficiency (percentage of oxygen consumption coupled to ATP synthesis) of intact skeletal muscle cells. A 30-minute pretreatment with curcumin reduced mitochondrial coupling efficiency by 17.0 ± 0.4% relative to vehicle (p < 0.008). Curcumin pretreatment also decreased the rate of hydrogen peroxide emission by 43 ± 13% compared to vehicle (p < 0.05). Analysis of cell respiration in the presence of curcumin revealed a 40 ± 4% increase in the rate of oxygen consumption upon curcumin administration (p < 0.05 compared to vehicle). No difference in mitochondrial coupling efficiency was observed between vehicle- and curcumin-pretreated cells after permeabilization of cell membranes (p > 0.7). The interaction between curcumin and ursolic acid, another natural compound that may improve blood glucose management, was also examined. Pretreatment with ursolic acid (0.12 μM) increased the mitochondrial coupling efficiency of intact cells by 4.1 ± 1.1% relative to vehicle (p < 0.008) and attenuated the effect of curcumin when the two compounds were used in combination. The observed changes to mitochondrial coupling efficiency and hydrogen peroxide emission were consistent with the established effects of curcumin on blood glucose control. Our findings also show that changes to mitochondrial coupling efficiency after curcumin pretreatment may go undetected unless cells are assessed in the intact condition. Copyright © 2017 Elsevier Inc. All rights reserved.

Coal reburning for cyclone boiler NO{sub x} control demonstration. Quarterly report No. 6, July--September, 1991

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1991-12-31

It is the objective of the Coal Reburning for Cyclone Boiler NO{sub x} Control Project to fully establish that the cola reburning clean coal technology offers cost-effective alternatives to cyclone operating electric utilities for overall oxides of nitrogen control. The project will evaluate the applicability of the reburning technology for reducing NO{sub x} emissions in full scale cyclone-fired boilers which use coal as a primary fuel. The performance goals while burning coal are: (1) Greater than 50 percent reduction in NO{sub x} emissions, as referenced to the uncontrolled (baseline) conditions at full load. (2) No serious impact on cyclone combustormore » operation, boiler efficiency or boiler fireside performance (corrosion and deposition), or boiler ash removal system performance.« less

Coal reburning for cyclone boiler NO sub x control demonstration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1991-01-01

It is the objective of the Coal Reburning for Cyclone Boiler NO{sub x} Control Project to fully establish that the cola reburning clean coal technology offers cost-effective alternatives to cyclone operating electric utilities for overall oxides of nitrogen control. The project will evaluate the applicability of the reburning technology for reducing NO{sub x} emissions in full scale cyclone-fired boilers which use coal as a primary fuel. The performance goals while burning coal are: (1) Greater than 50 percent reduction in NO{sub x} emissions, as referenced to the uncontrolled (baseline) conditions at full load. (2) No serious impact on cyclone combustormore » operation, boiler efficiency or boiler fireside performance (corrosion and deposition), or boiler ash removal system performance.« less

Pollution reduction technologies being applied to small coal-fired boiler systems in Poland

DOE Office of Scientific and Technical Information (OSTI.GOV)

Markussen, J.M.; Gyorke, D.F.

1997-12-31

To help in alleviating air pollution problems in Poland, various US environmental technologies are being installed in the city of Krakow to reduce emissions from short-stack coal- and coke-fired boilers. Introduction of low-cost, effective US pollution abatement and energy efficiency technologies is being completed through the US-Polish Krakow Clean Fossil Fuels and Energy Efficiency Program. Seven US firms are currently participating in the program; five projects are well under way and two are in the design phase. The technologies being applied in Krakow include modern district heating equipment and controls, coal preparation techniques, micronized coal combustion, automatic combustion controls, andmore » high-efficiency particulate control equipment. These technologies will be discussed along with pollutant reduction results obtained to date. Applications of these technologies are providing some efficient and economical answers to Krakow`s severe air pollution problems. Certainly, these technologies could be equally effective in many industrial cities throughout the world with similar air pollution concerns.« less

78 FR 29815 - Control of Air Pollution From Motor Vehicles: Tier 3 Motor Vehicle Emission and Fuel Standards

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-21

...This action would establish more stringent vehicle emissions standards and reduce the sulfur content of gasoline beginning in 2017, as part of a systems approach to addressing the impacts of motor vehicles and fuels on air quality and public health. The proposed gasoline sulfur standard would make emission control systems more effective for both existing and new vehicles, and would enable more stringent vehicle emissions standards. The proposed vehicle standards would reduce both tailpipe and evaporative emissions from passenger cars, light-duty trucks, medium-duty passenger vehicles, and some heavy-duty vehicles. This would result in significant reductions in pollutants such as ozone, particulate matter, and air toxics across the country and help state and local agencies in their efforts to attain and maintain health-based National Ambient Air Quality Standards. Motor vehicles are an important source of exposure to air pollution both regionally and near roads. These proposed vehicle standards are intended to harmonize with California's Low Emission Vehicle program, thus creating a federal vehicle emissions program that would allow automakers to sell the same vehicles in all 50 states. The proposed vehicle standards would be implemented over the same timeframe as the greenhouse gas/fuel efficiency standards for light-duty vehicles, as part of a comprehensive approach toward regulating emissions from motor vehicles.

Appraisal of Emissions from Ocean-going Vessels Coming to Kolkata Port, India

NASA Astrophysics Data System (ADS)

Mandal, Anindita; Biswas, Jhumoor; Roychowdhury, Soma; Farooqui, Zuber M.

2017-12-01

Rapid economic growth has escalated India's share in international trade. The pressure on these ports, which handle a substantial portion of the trade, has increased to perform with optimal efficiency, and decrease turnaround time so as to increase the number of ships visiting the port area. The caveat is that increased shipping activity is accompanied by enhanced emissions of harmful pollutants and green house gases. This study has revealed increased turnaround time for ships resulting in substantial emissions from auxiliary engines. There should be an optimum balance between operational control and environmental control of pollutants. Kolkata is a megacity with active riverine ports that can generate high levels of air quality emissions, especially NOx, SOx and particulate matter. An exhaustive annual emissions inventory based on ocean going vessels activity has been developed for 2013-2014 for Kolkata port, using recent EPA approved methodology. This includes greenhouse gas emissions from marine engines as well. The study indicates that amongst the different categories of ocean going ships, containers contribute the most (49%) of air and greenhouse gas emissions in 75th percentile class and above followed by general cargo (14%) and oil tankers (13%). The study depicts existing status of marine emissions in Kolkata port from ocean going vessels, which would serve in development of integrated air quality and climate change management plans and serve as a prototype for other major ports of India.

Characterization of particle bound organic carbon from diesel vehicles equipped with advanced emission control technologies.

PubMed

Pakbin, Payam; Ning, Zhi; Schauer, James J; Sioutas, Constantinos

2009-07-01

A chassis dynamometer study was carried out by the University of Southern California in collaboration with the Air Resources Board (CARB) to investigate the physical, chemical, and toxicological characteristics of diesel emissions of particulate matter (PM) from heavy-duty vehicles. These heavy-duty diesel vehicles (HDDV) were equipped with advanced emission control technologies, designed to meet CARB retrofit regulations. A HDDV without any emission control devices was used as the baseline vehicle. Three advanced emission control technologies; continuously regenerating technology (CRT), zeolite- and vanadium-based selective catalytic reduction technologies (Z-SCRT and V-SCRT), were tested under transient (UDDS) (1) and cruise (80 kmph) driving cycles to simulate real-world driving conditions. This paper focuses on the characterization of the particle bound organic species from the vehicle exhaust. Physical and chemical properties of PM emissions have been reported by Biswas et al. Atmos. Environ. 2008, 42, 5622-5634) and Hu et al. (Atmos. Environ. 2008, submitted) Significant reductions in the emission factors (microg/mile) of particle bound organic compounds were observed in HDDV equipped with advanced emission control technologies. V-SCRT and Z-SCRT effectively reduced PAHs, hopanes and steranes, n-alkanes and acids by more than 99%, and often to levels below detection limits for both cruise and UDDS cycles. The CRT technology also showed similar reductions with SCRT for medium and high molecular weight PAHs, acids, but with slightly lower removal efficiencies for other organic compounds. Ratios of particle bound organics-to-OC mass (microg/g) from the baseline exhaust were compared with their respective ratios in diesel fuel and lubricating oil, which revealed that hopanes and steranes originate from lubricating oil, whereas PAHs can either form during the combustion process or originate from diesel fuel itself. With the introduction of emission control technologies, the particle bound organics-to-OC ratios (microg/g) decreased considerably for PAHs, while the reduction was insignificant for hopanes and steranes, implying that fuel and lubricating oil have substantially different contributions to the total OC emitted by vehicles operating with after-treatment control devices compared to the baseline vehicle since these control technologies had a much larger impact on PAH OC than hopanes and steranes OC.

Elucidating secondary organic aerosol from diesel and gasoline vehicles through detailed characterization of organic carbon emissions

PubMed Central

Gentner, Drew R.; Isaacman, Gabriel; Worton, David R.; Chan, Arthur W. H.; Dallmann, Timothy R.; Davis, Laura; Liu, Shang; Day, Douglas A.; Russell, Lynn M.; Wilson, Kevin R.; Weber, Robin; Guha, Abhinav; Harley, Robert A.; Goldstein, Allen H.

2012-01-01

Emissions from gasoline and diesel vehicles are predominant anthropogenic sources of reactive gas-phase organic carbon and key precursors to secondary organic aerosol (SOA) in urban areas. Their relative importance for aerosol formation is a controversial issue with implications for air quality control policy and public health. We characterize the chemical composition, mass distribution, and organic aerosol formation potential of emissions from gasoline and diesel vehicles, and find diesel exhaust is seven times more efficient at forming aerosol than gasoline exhaust. However, both sources are important for air quality; depending on a region’s fuel use, diesel is responsible for 65% to 90% of vehicular-derived SOA, with substantial contributions from aromatic and aliphatic hydrocarbons. Including these insights on source characterization and SOA formation will improve regional pollution control policies, fuel regulations, and methodologies for future measurement, laboratory, and modeling studies. PMID:23091031

Elucidating secondary organic aerosol from diesel and gasoline vehicles through detailed characterization of organic carbon emissions.

PubMed

Gentner, Drew R; Isaacman, Gabriel; Worton, David R; Chan, Arthur W H; Dallmann, Timothy R; Davis, Laura; Liu, Shang; Day, Douglas A; Russell, Lynn M; Wilson, Kevin R; Weber, Robin; Guha, Abhinav; Harley, Robert A; Goldstein, Allen H

2012-11-06

Emissions from gasoline and diesel vehicles are predominant anthropogenic sources of reactive gas-phase organic carbon and key precursors to secondary organic aerosol (SOA) in urban areas. Their relative importance for aerosol formation is a controversial issue with implications for air quality control policy and public health. We characterize the chemical composition, mass distribution, and organic aerosol formation potential of emissions from gasoline and diesel vehicles, and find diesel exhaust is seven times more efficient at forming aerosol than gasoline exhaust. However, both sources are important for air quality; depending on a region's fuel use, diesel is responsible for 65% to 90% of vehicular-derived SOA, with substantial contributions from aromatic and aliphatic hydrocarbons. Including these insights on source characterization and SOA formation will improve regional pollution control policies, fuel regulations, and methodologies for future measurement, laboratory, and modeling studies.

A new process and equipment for waste minimization: Conversion of NO(x) scrubber liquor to fertilizer

NASA Technical Reports Server (NTRS)

Parrish, Clyde F.; Barile, Ronald G.; Gamble, Paul H.; Lueck, Dale E.; Young, Rebecca C.

1995-01-01

A new emissions control system for the oxidizer scrubbers that eliminates the current oxidizer liquor waste and lowers the NO(x) emissions is described. Since fueling and deservicing spacecraft constitute the primary operations in which environmental emissions occur, this will eliminate the second largest waste stream at KSC. This effort is in accord with Executive Order No. 12856 (Federal Compliance with Right-to-Know Laws and Pollution Prevention Requirements, data 6 Aug. 1993) and Executive Order No. 12873 (Federal Acquisition, Recycling, and Waste Prevention, dated 20 Oct. 1993). A recent study found that the efficiencies of the oxidizer scrubbers during normal operations ranged from 70 percent to 99 percent. The new scrubber liquor starts with 1% hydrogen peroxide at a pH of 7 and the process control system adds hydrogen peroxide and potassium hydroxide to the scrubber liquor to maintain those initial conditions. The result is the formation of a solution of potassium nitrate, which is sold as a fertilizer. This report describes the equipment and procedures used to monitor and control the conversion of the scrubber liquor to fertilizer, while reducing the scrubber emissions.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blystone, P.G.; Goltz, H.R.; Springer, J. Jr.

The reduction of volatile organic compound (VOC) emissions is a significant goal of the 1990 Clean Air Act. Industrial operations relating to surface preparation, surface coating and paint striping operations constitute one of the largest industrial sources of VOC emissions. This paper describes a new emission control system offered by Purus, Inc. which captures and recovers VOCs from paint stripping operations. The system is based on an on-site adsorption-desorption process which utilizes a specialized polymeric resin adsorbent. Adsorbent beds are regenerated through a computer controlled pressure-temperature swing process (PTSA). The adsorbent resin offers significant operational advantages over conventional activated carbonmore » adsorbents with respect to treating air laden with methyl ethyl ketone (MEK) vapors. Treatment of MEK with activated carbon can be problematic due to reactivity (degradation) and high heats of adsorption of ketones with carbon. The Purus process was successfully demonstrated at Tinker Air Force Base in or under the EPA`s Waste Reduction Evaluation at Federal Sites program. MEK emissions from a paint stripping booth vent were controlled at greater than 95% reduction levels. The recovered solvent was returned to depainting process and reused with no loss in paint stripping efficiency.« less

Characterization of Engine Control Authority on HCCI Combustion as the High Load Limit is Approached

DOE Office of Scientific and Technical Information (OSTI.GOV)

Szybist, James P; Edwards, Kevin Dean; Foster, Matthew

2013-01-01

While the potential emissions and efficiency benefits of homogeneous charge compression ignition (HCCI) combustion are well known, realizing the potentials on a production intent engine presents numerous challenges. In this study we focus on characterizing the authority of the available engine controls as the high load limit of HCCI combustion is approached. The experimental work is performed on a boosted single-cylinder research engine equipped with direct injection (DI) fueling, cooled external exhaust gas recirculation (EGR), and a hydraulic valve actuation (HVA) valve train to enable the negative valve overlap (NVO) breathing strategy. Valve lift and duration are held constant whilemore » phasing is varied in an effort to make the results as relevant as possible to production intent cam-based variable valve actuation (VVA) systems on multi-cylinder engines. Results presented include engine loads from 350 to 650 kPa IMEPnet and manifold pressure from 98 to 190 kPaa at 2000 rpm. It is found that in order to increase engine load to 650 kPa IMEPnet, it is necessary to increase manifold pressure and external EGR while reducing the NVO duration. Both NVO duration and fuel injection timing are effective means of controlling combustion phasing, with NVO duration being a coarse control and fuel injection timing being a fine control. NOX emissions are low throughout the study, with emissions below 0.1 g/kW-h at all boosted HCCI conditions, while good combustion efficiency is maintained (>96.5%). Net indicated thermal efficiency increases with load up to 600 kPa IMEPnet, where a peak efficiency of 41% is achieved. Results of independent parametric investigations are presented on the effect of external EGR, intake effect of manifold pressure, and the effect of NVO duration. It is found that increasing EGR at a constant manifold pressure and increasing manifold pressure at a constant EGR rate both have the effect of retarding combustion phasing. It is also found that combustion phasing becomes increasingly sensitive to NVO duration as engine load increases. Finally, comparisons are made between three commonly used noise metrics (AVL noise meter, ringing intensity (RI), and maximum pressure rise rate (MPRR)). It is found that compared to the AVL noise meter, RI significantly underestimates combustion noise under boosted conditions.« less

Evaluating the Performance of Household Liquefied Petroleum Gas Cookstoves.

PubMed

Shen, Guofeng; Hays, Michael D; Smith, Kirk R; Williams, Craig; Faircloth, Jerroll W; Jetter, James J

2018-01-16

Liquefied petroleum gas (LPG) cookstoves are considered to be an important solution for mitigating household air pollution; however, their performance has rarely been evaluated. To fill the data and knowledge gaps in this important area, 89 laboratory tests were conducted to quantify efficiencies and pollutant emissions from five commercially available household LPG stoves under different burning conditions. The mean thermal efficiency (±standard deviation) for the tested LPG cookstoves was 51 ± 6%, meeting guidelines for the highest tier level (Tier 4) under the International Organization for Standardization, International Workshop Agreement 11. Emission factors of CO 2 , CO, THC, CH 4 , and NO x on the basis of useful energy delivered (MJ d ) were 142 ± 17, 0.77 ± 0.55, 130 ± 196, 5.6 ± 8.2, and 46 ± 9 mg/MJ d , respectively. Approximately 90% of the PM 2.5 data were below the detection limit, corresponding to an emission rate below 0.11 mg/min. For those data above the detection limit, the average emission factor was 2.4 ± 1.6 mg/MJ d , with a mean emission rate of 0.20 ± 0.16 mg/min. Under the specified gas pressure (2.8 kPa), but with the burner control set to minimum air flow rate, less complete combustion resulted in a visually yellow flame, and CO, PM 2.5 , EC, and BC emissions all increased. LPG cookstoves met guidelines for Tier 4 for both CO and PM 2.5 emissions and mostly met the World Health Organization Emission Rate Targets set to protect human health.

Strong and reversible modulation of carbon nanotube-silicon heterojunction solar cells by an interfacial oxide layer.

PubMed

Jia, Yi; Cao, Anyuan; Kang, Feiyu; Li, Peixu; Gui, Xuchun; Zhang, Luhui; Shi, Enzheng; Wei, Jinquan; Wang, Kunlin; Zhu, Hongwei; Wu, Dehai

2012-06-21

Deposition of nanostructures such as carbon nanotubes on Si wafers to make heterojunction structures is a promising route toward high efficiency solar cells with reduced cost. Here, we show a significant enhancement in the cell characteristics and power conversion efficiency by growing a silicon oxide layer at the interface between the nanotube film and Si substrate. The cell efficiency increases steadily from 0.5% without interfacial oxide to 8.8% with an optimal oxide thickness of about 1 nm. This systematic study reveals that formation of an oxide layer switches charge transport from thermionic emission to a mixture of thermionic emission and tunneling and improves overall diode properties, which are critical factors for tailoring the cell behavior. By controlled formation and removal of interfacial oxide, we demonstrate oscillation of the cell parameters between two extreme states, where the cell efficiency can be reversibly altered by a factor of 500. Our results suggest that the oxide layer plays an important role in Si-based photovoltaics, and it might be utilized to tune the cell performance in various nanostructure-Si heterojunction structures.

Aerosol Health Impact Source Attribution Studies with the CMAQ Adjoint Air Quality Model

NASA Astrophysics Data System (ADS)

Turner, M. D.

Fine particulate matter (PM2.5) is an air pollutant consisting of a mixture of solid and liquid particles suspended in the atmosphere. Knowledge of the sources and distributions of PM2.5 is important for many reasons, two of which are that PM2.5 has an adverse effect on human health and also an effect on climate change. Recent studies have suggested that health benefits resulting from a unit decrease in black carbon (BC) are four to nine times larger than benefits resulting from an equivalent change in PM2.5 mass. The goal of this thesis is to quantify the role of emissions from different sectors and different locations in governing the total health impacts, risk, and maximum individual risk of exposure to BC both nationally and regionally in the US. We develop and use the CMAQ adjoint model to quantify the role of emissions from all modeled sectors, times, and locations on premature deaths attributed to exposure to BC. From a national analysis, we find that damages resulting from anthropogenic emissions of BC are strongly correlated with population and premature death. However, we find little correlation between damages and emission magnitude, suggesting that controls on the largest emissions may not be the most efficient means of reducing damages resulting from BC emissions. Rather, the best proxy for locations with damaging BC emissions is locations where premature deaths occur. Onroad diesel and nonroad vehicle emissions are the largest contributors to premature deaths attributed to exposure to BC, while onroad gasoline emissions cause the highest deaths per amount emitted. Additionally, emissions in fall and winter contribute to more premature deaths (and more per amount emitted) than emissions in spring and summer. From a regional analysis, we find that emissions from outside each of six urban areas account for 7% to 27% of the premature deaths attributed to exposure to BC within the region. Within the region encompassing New York City and Philadelphia, reductions in emissions from large industrial combustion sources that are not classified as EGUs (i.e., non-EGU) are estimated to have up to triple the benefits per unit emission of reductions to onroad diesel sectors, and provide similar benefits per unit of reduced emission to that of onroad gasoline emissions in the region. While a majority of vehicle emission controls that regulate PM focus on diesel emissions, our analysis shows the most efficient target for stricter controls is actually onroad gasoline emissions. From an analysis of the health impacts of BC emissions on specific demographic populations, we find that emissions in the southern half of the US tend to disproportionally affect persons with a below high school education and persons below 50% of the poverty level. Analysis of national risk (independent of population and mortality rates) shows that the largest risks are associated with drier climates, due to the increased atmospheric lifetime resulting from less wet removal of aerosols. Lastly, analysis of the impacts of BC emissions on maximum individual risk shows that contributions to maximum individual risk are weakly to strongly correlated with emissions (R2 ranging from 0.23 in the San Joaquin Valley to 0.93 in the Dallas region). Overall, this thesis shows the value of high-resolution, adjoint-based source attribution studies for determining the locations, seasons, and sectors that have the greatest estimated impact on human health in air quality models.

Effects of Aftermarket Control Technologies on Gas and ...

EPA Pesticide Factsheets

Particulate matter (PM) originating from diesel combustion is a public health concern due to its association with adverse effects on respiratory and cardiovascular diseases and lung cancer. This study investigated emissions from three stationary diesel engines (gensets) with varying power output (230 kW, 400 kW, and 600 kW) at 50% and 90% load to determine concentrations of gaseous (GROS) and PM reactive oxygen species (PMROS). In addition, the influence of three modern emission control technologies on ROS emissions was evaluated: active and passive diesel particulate filters (A-DPF and P-DPF) and a diesel oxidation catalyst (DOC). PMROS made up 30-50% of the total ROS measured without aftermarket controls. All applied controls removed PMROS by more than 75% on average. However, the oxidative potential of PM downstream of these devices was not diminished at the same rate and particles surviving the A-PDF had an even higher oxidative potential on a per PM mass basis compared to the particles emitted by uncontrolled gensets. Further, the GROS as compared to PMROS emissions were not reduced with the same efficiency (<36%). GROS concentrations were highest with the DOC in use, indicating continued formation of GROS with this control. Correlation analyses showed that PMROS and to a lesser extent GROS have a good correlation with semi-volatile organic carbon (OC1) sub-fraction. In addition, results suggest that chemical composition, rather than PM size, is re

40 CFR 60.565 - Reporting and recordkeeping requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... emission control efficiency of a combustion device or the outlet concentration of TOC (minus methane and... performance test period, and (ii) The percent reduction of TOC (minus methane and ethane) achieved by the incinerator, the concentration of TOC (minus methane and ethane) (ppmv, by compound) at the outlet of the...

40 CFR 60.565 - Reporting and recordkeeping requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... emission control efficiency of a combustion device or the outlet concentration of TOC (minus methane and... performance test period, and (ii) The percent reduction of TOC (minus methane and ethane) achieved by the incinerator, the concentration of TOC (minus methane and ethane) (ppmv, by compound) at the outlet of the...

40 CFR 60.565 - Reporting and recordkeeping requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... emission control efficiency of a combustion device or the outlet concentration of TOC (minus methane and... performance test period, and (ii) The percent reduction of TOC (minus methane and ethane) achieved by the incinerator, the concentration of TOC (minus methane and ethane) (ppmv, by compound) at the outlet of the...

40 CFR 60.565 - Reporting and recordkeeping requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... emission control efficiency of a combustion device or the outlet concentration of TOC (minus methane and... performance test period, and (ii) The percent reduction of TOC (minus methane and ethane) achieved by the incinerator, the concentration of TOC (minus methane and ethane) (ppmv, by compound) at the outlet of the...

40 CFR 60.565 - Reporting and recordkeeping requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... emission control efficiency of a combustion device or the outlet concentration of TOC (minus methane and... performance test period, and (ii) The percent reduction of TOC (minus methane and ethane) achieved by the incinerator, the concentration of TOC (minus methane and ethane) (ppmv, by compound) at the outlet of the...

40 CFR 91.427 - Catalyst thermal stress resistance evaluation.

Code of Federal Regulations, 2014 CFR

2014-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Gaseous Exhaust Test... efficiency. The thermal stress is imposed on the test catalyst by exposing it to quiescent heated air in an... that the catalyst being tested was not designed to reduce/oxidize. The engine manufacturer must specify...

40 CFR 91.427 - Catalyst thermal stress resistance evaluation.

Code of Federal Regulations, 2011 CFR

2011-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Gaseous Exhaust Test... efficiency. The thermal stress is imposed on the test catalyst by exposing it to quiescent heated air in an... that the catalyst being tested was not designed to reduce/oxidize. The engine manufacturer must specify...

40 CFR 91.427 - Catalyst thermal stress resistance evaluation.

Code of Federal Regulations, 2010 CFR

2010-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Gaseous Exhaust Test... efficiency. The thermal stress is imposed on the test catalyst by exposing it to quiescent heated air in an... that the catalyst being tested was not designed to reduce/oxidize. The engine manufacturer must specify...

40 CFR 91.427 - Catalyst thermal stress resistance evaluation.

Code of Federal Regulations, 2013 CFR

2013-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Gaseous Exhaust Test... efficiency. The thermal stress is imposed on the test catalyst by exposing it to quiescent heated air in an... that the catalyst being tested was not designed to reduce/oxidize. The engine manufacturer must specify...

40 CFR 91.427 - Catalyst thermal stress resistance evaluation.

Code of Federal Regulations, 2012 CFR

2012-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Gaseous Exhaust Test... efficiency. The thermal stress is imposed on the test catalyst by exposing it to quiescent heated air in an... that the catalyst being tested was not designed to reduce/oxidize. The engine manufacturer must specify...

High Efficiency, Clean Combustion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Donald Stanton

2010-03-31

Energy use in trucks has been increasing at a faster rate than that of automobiles within the U.S. transportation sector. According to the Energy Information Administration (EIA) Annual Energy Outlook (AEO), a 23% increase in fuel consumption for the U.S. heavy duty truck segment is expected between 2009 to 2020. The heavy duty vehicle oil consumption is projected to grow between 2009 and 2050 while light duty vehicle (LDV) fuel consumption will eventually experience a decrease. By 2050, the oil consumption rate by LDVs is anticipated to decrease below 2009 levels due to CAFE standards and biofuel use. In contrast,more » the heavy duty oil consumption rate is anticipated to double. The increasing trend in oil consumption for heavy trucks is linked to the vitality, security, and growth of the U.S. economy. An essential part of a stable and vibrant U.S. economy is a productive U.S. trucking industry. Studies have shown that the U.S. gross domestic product (GDP) is strongly correlated to freight transport. Over 90% of all U.S. freight tonnage is transported by diesel power and over 75% is transported by trucks. Given the vital role that the trucking industry plays in the economy, improving the efficiency of the transportation of goods was a central focus of the Cummins High Efficient Clean Combustion (HECC) program. In a commercial vehicle, the diesel engine remains the largest source of fuel efficiency loss, but remains the greatest opportunity for fuel efficiency improvements. In addition to reducing oil consumption and the dependency on foreign oil, this project will mitigate the impact on the environment by meeting US EPA 2010 emissions regulations. Innovation is a key element in sustaining a U.S. trucking industry that is competitive in global markets. Unlike passenger vehicles, the trucking industry cannot simply downsize the vehicle and still transport the freight with improved efficiency. The truck manufacturing and supporting industries are faced with numerous challenges to reduce oil consumption and greenhouse gases, meet stringent emissions regulations, provide customer value, and improve safety. The HECC program successfully reduced engine fuel consumption and greenhouse gases while providing greater customer valve. The US EPA 2010 emissions standard poses a significant challenge for developing clean diesel powertrains that meet the DoE Vehicle Technologies Multi-Year Program Plan (MYPP) for fuel efficiency improvement while remaining affordable. Along with exhaust emissions, an emphasis on heavy duty vehicle fuel efficiency is being driven by increased energy costs as well as the potential regulation of greenhouse gases. An important element of the success of meeting emissions while significantly improving efficiency is leveraging Cummins component technologies such as fuel injection equipment, aftertreatment, turbomahcinery, electronic controls, and combustion systems. Innovation in component technology coupled with system integration is enabling Cummins to move forward with the development of high efficiency clean diesel products with a long term goal of reaching a 55% peak brake thermal efficiency for the engine plus aftertreatment system. The first step in developing high efficiency clean products has been supported by the DoE co-sponsored HECC program. The objectives of the HECC program are: (1) To design and develop advanced diesel engine architectures capable of achieving US EPA 2010 emission regulations while improving the brake thermal efficiency by 10% compared to the baseline (a state of the art 2007 production diesel engine). (2) To design and develop components and subsystems (fuel systems, air handling, controls, etc) to enable construction and development of multi-cylinder engines. (3) To perform an assessment of the commercial viability of the newly developed engine technology. (4) To specify fuel properties conducive to improvements in emissions, reliability, and fuel efficiency for engines using high-efficiency clean combustion (HECC) technologies. To demonstrate the technology is compatible with B20 (biodiesel). (5) To further improve the brake thermal efficiency of the engine as integrated into the vehicle. To demonstrate robustness and commercial viability of the HECC engine technology as integrated into the vehicles. The Cummins HECC program supported the Advanced Combustion Engine R&D and Fuels Technology initiatives of the DoE Vehicle Technologies Multi-Year Program Plan (MYPP). In particular, the HECC project goals enabled the DoE Vehicle Technologies Program (VTP) to meet energy-efficiency improvement targets for advanced combustion engines suitable for passenger and commercial vehicles, as well as addressing technology barriers and R&D needs that are common between passenger and commercial vehicle applications of advanced combustion engines.« less

Hybrid metasurfaces for microwave reflection and infrared emission reduction.

PubMed

Pang, Yongqiang; Li, Yongfeng; Yan, Mingbao; Liu, Dongqing; Wang, Jiafu; Xu, Zhuo; Qu, Shaobo

2018-04-30

Controlling of electromagnetic wave radiation is of great importance in many fields. In this work, a hybrid metasurface (HMS) is designed to simultaneously reduce the microwave reflection and the infrared emission. The HMS is composed of the metal/dielectric/metal/dielectric/metal configuration. The reflection reduction at microwave frequencies mainly results from the phase cancellation technique, while the infrared emission reduction is due to the reflection of the metal with a high filling ration in the top layer. It has been analytically indicated that reflection reduction with an efficiency larger than 10 dB can be achieved in the frequency band of 8.2-18 GHz, and this has been well verified by the simulated and experimental results. Meanwhile, the designed HMS displays a low emission performance in the infrared band, with the emissivity less than 0.27 from 3 to 14 μm. It is believed that our proposal may find the application of multispectral stealth technology.

Bright Single InAsP Quantum Dots at Telecom Wavelengths in Position-Controlled InP Nanowires: The Role of the Photonic Waveguide

NASA Astrophysics Data System (ADS)

Haffouz, Sofiane; Zeuner, Katharina D.; Dalacu, Dan; Poole, Philip J.; Lapointe, Jean; Poitras, Daniel; Mnaymneh, Khaled; Wu, Xiaohua; Couillard, Martin; Korkusinski, Marek; Schöll, Eva; Jöns, Klaus D.; Zwiller, Valery; Williams, Robin L.

2018-05-01

We report on the site-selected growth of bright single InAsP quantum dots embedded within InP photonic nanowire waveguides emitting at telecom wavelengths. We demonstrate a dramatic dependence of the emission rate on both the emission wavelength and the nanowire diameter. With an appropriately designed waveguide, tailored to the emission wavelength of the dot, an increase in count rate by nearly two orders of magnitude (0.4kcps to 35kcps) is obtained for quantum dots emitting in the telecom O-band. Using emission-wavelength-optimised waveguides, we demonstrate bright, narrow linewidth emission from single InAsP quantum dots with an unprecedented tuning range from 880nm to 1550nm. These results pave the way towards efficient single photon sources at telecom wavelengths using deterministically grown InAsP/InP nanowire quantum dots.

Polarized quantum dot emission in electrohydrodynamic jet printed photonic crystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

See, Gloria G.; Xu, Lu; Nuzzo, Ralph G.

2015-08-03

Tailored optical output, such as color purity and efficient optical intensity, are critical considerations for displays, particularly in mobile applications. To this end, we demonstrate a replica molded photonic crystal structure with embedded quantum dots. Electrohydrodynamic jet printing is used to control the position of the quantum dots within the device structure. This results in significantly less waste of the quantum dot material than application through drop-casting or spin coating. In addition, the targeted placement of the quantum dots minimizes any emission outside of the resonant enhancement field, which enables an 8× output enhancement and highly polarized emission from themore » photonic crystal structure.« less

OppoRTUnities Abound

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deru, Michael

According to the U.S. Energy Information Administration, HVAC accounts for approximately 38 percent of U.S. commercial buildings' primary energy consumption and a slightly higher percentage of their greenhouse-gas emissions. We have seen incredible gains made with lighting, going from incandescent and T12 fluorescent bulbs to high-efficiency LEDS, but there are even greater advances to be made with HVAC. Gains of 20 percent to 30 percent easily can be made by replacing older degraded equipment with new high-efficiency equipment. Even more savings are possible with an integrated engineering approach yielding optimized system designs combined with highly efficient controls.

NASA Puffin Electric Tailsitter VTOL Concept

NASA Technical Reports Server (NTRS)

Moore, Mark D.

2010-01-01

Electric propulsion offers dramatic new vehicle mission capabilities, not possible with turbine or reciprocating engines; including high reliability and efficiency, low engine weight and maintenance, low cooling drag and volume required, very low noise and vibration, and zero emissions. The only penalizing characteristic of electric propulsion is the current energy storage technology level, which is set to triple over the next 5-10 years through huge new investments in this field. Most importantly, electric propulsion offers incredible new degrees of freedom in aircraft system integration to achieve unprecedented levels of aerodynamic, propulsive, control, and structural synergistic coupling. A unique characteristic of electric propulsion is that the technology is nearly scale-free, permitting small motors to be parallelized for fail-safe redundancy, or distributed across the airframe for tightly coupled interdisciplinary functionality without significant impacts in motor-controller efficiency or specific weight. Maximizing the potential benefit of electric propulsion is dependent on applying this technology to synergistic mission concepts. The vehicle missions with the most benefit include those which constrain environmental impact (or limit noise, exhaust, or emission signatures) are short range, or where large differences exist in the propulsion system sizing between takeoff and cruise conditions. Electric propulsion offers the following unique capabilities that other propulsion systems can t provide for short range Vertical Takeoff and Landing (VTOL) aircraft; elimination of engine noise and emissions, drastic reduction in engine cooling and radiated heat, drastic reduction in vehicle vibration levels, drastic improvement in reliability and operating costs, variable speed output at full power, for improved cruise efficiency at low tip-speed, elimination of high/hot sizing penalty, and reduction of engine-out penalties.

Investigating Electrostatic Precipitator Design Parameters for Efficient Control of Particulate Matter in Thermal Power Plant: A Case Study

NASA Astrophysics Data System (ADS)

Rai, P.; Gautam, N.; Chandra, H.

2018-06-01

This work deals with the analysis and modification of operational parameters for meeting the emission standards, set by Central Pollution Control Board (CPCB)/State Pollution Control Board (SPCB) from time to time of electrostatic precipitator (ESP). The analysis is carried out by using standard chemical analysis supplemented by the relevant data collected from Korba East Phase (Ph)-III thermal power plant, under Chhattisgarh State Electricity Board (CSEB) operating at Korba, Chhattisgarh. Chemical analysis is used to predict the emission level for different parameters of ESP. The results reveal that for a constant outlet PM concentration and fly ash percentage, the total collection area decreases with the increase in migration velocity. For constant migration velocity and outlet PM concentration, the total collection area increases with the increase in the fly ash percent. For constant migration velocity and outlet e PM concentration, the total collection area increases with the ash content in the coal. i.e. from minimum ash to maximum ash. As far as the efficiency is concerned, it increases with the fly ash percent, ash content and the inlet dust concentration but decreases with the outlet PM concentration at constant migration velocity, fly ash and ash content.

Investigating Electrostatic Precipitator Design Parameters for Efficient Control of Particulate Matter in Thermal Power Plant: A Case Study

NASA Astrophysics Data System (ADS)

Rai, P.; Gautam, N.; Chandra, H.

2018-02-01

This work deals with the analysis and modification of operational parameters for meeting the emission standards, set by Central Pollution Control Board (CPCB)/State Pollution Control Board (SPCB) from time to time of electrostatic precipitator (ESP). The analysis is carried out by using standard chemical analysis supplemented by the relevant data collected from Korba East Phase (Ph)-III thermal power plant, under Chhattisgarh State Electricity Board (CSEB) operating at Korba, Chhattisgarh. Chemical analysis is used to predict the emission level for different parameters of ESP. The results reveal that for a constant outlet PM concentration and fly ash percentage, the total collection area decreases with the increase in migration velocity. For constant migration velocity and outlet PM concentration, the total collection area increases with the increase in the fly ash percent. For constant migration velocity and outlet e PM concentration, the total collection area increases with the ash content in the coal. i.e. from minimum ash to maximum ash. As far as the efficiency is concerned, it increases with the fly ash percent, ash content and the inlet dust concentration but decreases with the outlet PM concentration at constant migration velocity, fly ash and ash content.

Balancing effluent quality, economic cost and greenhouse gas emissions during the evaluation of (plant-wide) control/operational strategies in WWTPs.

PubMed

Flores-Alsina, Xavier; Arnell, Magnus; Amerlinck, Youri; Corominas, Lluís; Gernaey, Krist V; Guo, Lisha; Lindblom, Erik; Nopens, Ingmar; Porro, Jose; Shaw, Andy; Snip, Laura; Vanrolleghem, Peter A; Jeppsson, Ulf

2014-01-01

The objective of this paper was to show the potential additional insight that result from adding greenhouse gas (GHG) emissions to plant performance evaluation criteria, such as effluent quality (EQI) and operational cost (OCI) indices, when evaluating (plant-wide) control/operational strategies in wastewater treatment plants (WWTPs). The proposed GHG evaluation is based on a set of comprehensive dynamic models that estimate the most significant potential on-site and off-site sources of CO₂, CH₄ and N₂O. The study calculates and discusses the changes in EQI, OCI and the emission of GHGs as a consequence of varying the following four process variables: (i) the set point of aeration control in the activated sludge section; (ii) the removal efficiency of total suspended solids (TSS) in the primary clarifier; (iii) the temperature in the anaerobic digester; and (iv) the control of the flow of anaerobic digester supernatants coming from sludge treatment. Based upon the assumptions built into the model structures, simulation results highlight the potential undesirable effects of increased GHG production when carrying out local energy optimization of the aeration system in the activated sludge section and energy recovery from the AD. Although off-site CO₂ emissions may decrease, the effect is counterbalanced by increased N₂O emissions, especially since N₂O has a 300-fold stronger greenhouse effect than CO₂. The reported results emphasize the importance and usefulness of using multiple evaluation criteria to compare and evaluate (plant-wide) control strategies in a WWTP for more informed operational decision making. © 2013.

Assessment of emissions and removal of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) at start-up periods in a hazardous waste incinerator.

PubMed

Karademir, Aykan; Korucu, M Kemal

2013-07-01

A study was conducted to observe the changes in polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/F) levels and congener profiles in the flue gas of a hazardous waste incinerator during two start-up periods. Flue gas samplings were performed simultaneously through Air Pollution Control Devices (APCDs) (including boiler outlet, electrostatic precipitator (ESP) outlet, wet scrubbers (WS) outlet, and activated carbon (AC) filter outlet) in different combustion temperatures during a planned cold (long) start-up and an unplanned warm (short) start-up. The results showed that PCDD/F concentrations could be elevated during the start-up periods up to levels 3-4 times higher than those observed in the normal operation. Especially lower combustion temperatures in the short start-ups may cause high PCDD/F concentrations in the raw flue gas. Assessment of combustion temperatures and Furans/Dioxins values indicated that surface-catalyzed de novo synthesis was the dominant pathway in the formation of PCDD/Fs in the combustion units. PCDD/F removal efficiencies of Air Pollution Control Devices suggested that formation by de novo synthesis existed in ESP also when in operation, leading to increase of gaseous phase PCDD/Fs in ESP Particle-bound PCDD/Fs were removed mainly by ESP and WS, while gaseous phase PCDD/Fs were removed by WS, and more efficiently by AC filter. This paper evaluates PCDD/F emissions and removal performances of APCDs (ESP, wet scrubbers, and activated carbon) during two start-up periods in an incinerator. The main implications are the following: (1) start-up periods increase PCDD/F emissions up to 2-3 times in the incinerator; (2) low combustion temperatures in start-ups cause high PCDD/F emissions in raw gas; (3) formation of PCDD/Fs by de novo synthesis occurs in ESP; (4) AC is efficient in removing gaseous PCDD/Fs, but may increase particle-bound ones; and (5) scrubbers remove both gaseous and particle-bound PCDD/Fs efficiently.

The Effect of Ethanol Addition to Gasoline on Low- and Intermediate-Temperature Heat Release under Boosted Conditions in Kinetically Controlled Engines

NASA Astrophysics Data System (ADS)

Vuilleumier, David Malcolm

The detailed study of chemical kinetics in engines has become required to further advance engine efficiency while simultaneously lowering engine emissions. This push for higher efficiency engines is not caused by a lack of oil, but by efforts to reduce anthropogenic carbon dioxide emissions, that cause global warming. To operate in more efficient manners while reducing traditional pollutant emissions, modern internal combustion piston engines are forced to operate in regimes in which combustion is no longer fully transport limited, and instead is at least partially governed by chemical kinetics of combusting mixtures. Kinetically-controlled combustion allows the operation of piston engines at high compression ratios, with partially-premixed dilute charges; these operating conditions simultaneously provide high thermodynamic efficiency and low pollutant formation. The investigations presented in this dissertation study the effect of ethanol addition on the low-temperature chemistry of gasoline type fuels in engines. These investigations are carried out both in a simplified, fundamental engine experiment, named Homogeneous Charge Compression Ignition, as well as in more applied engine systems, named Gasoline Compression Ignition engines and Partial Fuel Stratification engines. These experimental investigations, and the accompanying modeling work, show that ethanol is an effective scavenger of radicals at low temperatures, and this inhibits the low temperature pathways of gasoline oxidation. Further, the investigations measure the sensitivity of gasoline auto-ignition to system pressure at conditions that are relevant to modern engines. It is shown that at pressures above 40 bar and temperatures below 850 Kelvin, gasoline begins to exhibit Low-Temperature Heat Release. However, the addition of 20% ethanol raises the pressure requirement to 60 bar, while the temperature requirement remains unchanged. These findings have major implications for a range of modern engines. Low-Temperature Heat Release significantly enhances the auto-ignition process, which limits the conditions under which advanced combustion strategies may operate. As these advanced combustion strategies are required to meet emissions and fuel-economy regulations, the findings of this dissertation may benefit and be incorporated into future engine design toolkits, such as detailed chemical kinetic mechanisms.

Enhanced Luminescence Performance of Quantum Wells by Coupling Piezo-Phototronic with Plasmonic Effects.

PubMed

Huang, Xin; Jiang, Chunyan; Du, Chunhua; Jing, Liang; Liu, Mengmeng; Hu, Weiguo; Wang, Zhong Lin

2016-12-27

With a promising prospect of light-emitting diodes as an attractive alternative to conventional light sources, remaining challenges still cannot be addressed owing to their limited efficiency. Among the continued scientific efforts, significant improvement on the emission efficiency has been achieved via either piezo-phototronic effect-based strain modulation or resonant excitation of plasmons in metallic nanostructures. Here, we present the investigation on the coupling process between piezo-phototronic effect and localized surface plasmonic resonance for enhancing the photoluminescence of InGaN/GaN quantum wells coated with Ag nanoparticles. The underlying physical mechanism of experimental results originates from tuning plasmonic resonance controlled by the shift of emission wavelength via piezo-phototronic effect, and it is further confirmed with the support of theoretical calculations. As a result, our research provides an approach to the integration of plasmonics with piezo-phototronic effect and brings widespread applications to high-efficiency artificial lighting, on-chip integrated plasmonic circuits, subwavelength optical communication, and micro-optoelectronic mechanical systems.

Changes in agricultural carbon emissions and factors that influence agricultural carbon emissions based on different stages in Xinjiang, China.

PubMed

Xiong, Chuanhe; Yang, Degang; Xia, Fuqiang; Huo, Jinwei

2016-11-10

Xinjiang's agricultural carbon emissions showed three stages of change, i.e., continued to rise, declined and continued to rise, during 1991-2014. The agriculture belonged to the "low emissions and high efficiency" agriculture category, with a lower agricultural carbon emission intensity. By using the logarithmic mean divisia index decomposition method, agricultural carbon emissions were decomposed into an efficiency factor, a structure factor, an economy factor, and a labour factor. We divided the study period into five stages based on the changes in efficiency factor and economy factor. Xinjiang showed different agricultural carbon emission characteristics at different stages. The degree of impact on agricultural carbon emissions at these stages depended on the combined effect of planting-animal husbandry carbon intensity and agricultural labour productivity. The economy factor was the critical factor to promote the increase in agricultural carbon emissions, while the main inhibiting factor for agricultural carbon emissions was the efficiency factor. The labour factor became more and more obvious in increasing agricultural carbon emissions. Finally, we discuss policy recommendations in terms of the main factors, including the development of agricultural science and technology (S&T), the establishment of three major mechanisms and transfer of rural labour in ethnic areas.

Spin injection in n-type resonant tunneling diodes.

PubMed

Orsi Gordo, Vanessa; Herval, Leonilson Ks; Galeti, Helder Va; Gobato, Yara Galvão; Brasil, Maria Jsp; Marques, Gilmar E; Henini, Mohamed; Airey, Robert J

2012-10-25

We have studied the polarized resolved photoluminescence of n-type GaAs/AlAs/GaAlAs resonant tunneling diodes under magnetic field parallel to the tunnel current. Under resonant tunneling conditions, we have observed two emission lines attributed to neutral (X) and negatively charged excitons (X-). We have observed a voltage-controlled circular polarization degree from the quantum well emission for both lines, with values up to -88% at 15 T at low voltages which are ascribed to an efficient spin injection from the 2D gases formed at the accumulation layers.

Modeling and Computation of Transboundary Industrial Pollution with Emission Permits Trading by Stochastic Differential Game

PubMed Central

2015-01-01

Transboundary industrial pollution requires international actions to control its formation and effects. In this paper, we present a stochastic differential game to model the transboundary industrial pollution problems with emission permits trading. More generally, the process of emission permits price is assumed to be stochastic and to follow a geometric Brownian motion (GBM). We make use of stochastic optimal control theory to derive the system of Hamilton-Jacobi-Bellman (HJB) equations satisfied by the value functions for the cooperative and the noncooperative games, respectively, and then propose a so-called fitted finite volume method to solve it. The efficiency and the usefulness of this method are illustrated by the numerical experiments. The two regions’ cooperative and noncooperative optimal emission paths, which maximize the regions’ discounted streams of the net revenues, together with the value functions, are obtained. Additionally, we can also obtain the threshold conditions for the two regions to decide whether they cooperate or not in different cases. The effects of parameters in the established model on the results have been also examined. All the results demonstrate that the stochastic emission permits prices can motivate the players to make more flexible strategic decisions in the games. PMID:26402322

Modeling and Computation of Transboundary Industrial Pollution with Emission Permits Trading by Stochastic Differential Game.

PubMed

Chang, Shuhua; Wang, Xinyu; Wang, Zheng

2015-01-01

Transboundary industrial pollution requires international actions to control its formation and effects. In this paper, we present a stochastic differential game to model the transboundary industrial pollution problems with emission permits trading. More generally, the process of emission permits price is assumed to be stochastic and to follow a geometric Brownian motion (GBM). We make use of stochastic optimal control theory to derive the system of Hamilton-Jacobi-Bellman (HJB) equations satisfied by the value functions for the cooperative and the noncooperative games, respectively, and then propose a so-called fitted finite volume method to solve it. The efficiency and the usefulness of this method are illustrated by the numerical experiments. The two regions' cooperative and noncooperative optimal emission paths, which maximize the regions' discounted streams of the net revenues, together with the value functions, are obtained. Additionally, we can also obtain the threshold conditions for the two regions to decide whether they cooperate or not in different cases. The effects of parameters in the established model on the results have been also examined. All the results demonstrate that the stochastic emission permits prices can motivate the players to make more flexible strategic decisions in the games.

Synthesis and optoelectronic properties of a heterobimetallic Pt(II)-Ir(III) complex used as a single-component emitter in white PLEDs.

PubMed

Li, Xiaoshuang; Liu, Yu; Luo, Jian; Zhang, Zhiyong; Shi, Danyan; Chen, Qing; Wang, Yafei; He, Juan; Li, Jianming; Lei, Gangtie; Zhu, Weiguo

2012-03-14

To tune aggregation/excimer emission and obtain a single active emitter for white polymer light-emitting devices (PLEDs), a heterobimetallic Pt(II)-Ir(III) complex of FIr(pic)-C(6)DBC(6)-(pic)PtF was designed and synthesized, in which C(6)DBC(6) is a di(phenyloxyhexyloxy) bridging group, FIr(pic) is an iridium(III) bis[(4,6-difluorophenyl)pyridinato-N,C(2)'] (picolinate) chromophore and FPt(pic) is a platinum(II) [(4,6-difluorophenyl)pyridinato-N,C(2)'] (picolinate) chromophore. Its physical and opto-electronic properties were investigated. Interestingly, the excimer emission was efficiently controlled by this heterobimetallic Pt(II)-Ir(III) complex compared to the PL profile of the mononuclear FPt(pic) complex in the solid state. Near-white emissions were obtained in the single emissive layer (SEL) PLEDs using this heterobimetallic Pt(II)-Ir(III) complex as a single dopant and poly(vinylcarbazole) as a host matrix at dopant concentrations from 0.5 wt% to 2 wt%. This work indicates that incorporating a non-planar iridium(III) complex into the planar platinum(II) complex can control aggregation/excimer emissions and a single phosphorescent emitter can be obtained to exhibit white emission in SEL devices.

Effect of spent mushroom substrate as a bulking agent on gaseous emissions and compost quality during pig manure composting.

PubMed

Li, Shuyan; Li, Danyang; Li, Jijin; Li, Yangyang; Li, Guoxue; Zang, Bing; Li, Yun

2018-05-01

The aim of this study was to investigate the gaseous emissions (CH 4 , N 2 O, and NH 3 ) and compost quality during the pig manure composting by adding spent mushroom substrate (SMS) as a bulking agent. The control treatment was also studied using corn stalk (CS) as a bulking agent. The experiment was conducted in a pilot scale composting reactor under aerobic condition with the initial C/N ratio of 20. Results showed that bulking agents significantly affected gaseous emissions and compost quality. Using SMS as a bulking agent improved composting efficiency by shortening the time for maturity. SMS increased germination index and humic acid of the final compost (by 13.44 and 41.94%, respectively) compared with CS. Furthermore, composting with SMS as a bulking agent could reduce nitrogen loss, NH 3 , and N 2 O emissions (by 13.57, 35.56, and 46.48%, respectively) compared with the control. SMS slightly increased CH 4 emission about 1.1 times of the CS. However, a 33.95% decrease in the global warming potential of CH 4 and N 2 O was obtained by adding SMS treatment. These results indicate that SMS is a favorable bulking agent for reducing gaseous emissions and increasing compost quality.

Incinerator toxic emissions: a brief summary of human health effects with a note on regulatory control.

PubMed

Rowat, S C

1999-05-01

Toxic emissions from municipal solid waste (MSW) and hazardous waste incineration are discussed, with reference to recent reviews and to government standards and controls. Studies of known effects of aromatic hydrocarbons, other organics, dioxins, metals, and gases, on fish, soils, plants, and particularly humans are briefly reviewed. A summary of potential problems with existing and proposed incineration is developed, including: (1) lack of toxicity data on unidentified organic emissions; (2) unavoidability of hazardous metal emissions as particles and volatiles; (3) inefficient stack operation resulting in unknown amounts of increased emissions; (4) formation in the stack of highly toxic dioxins and furans, especially under inefficient conditions, and their build-up in the environment and in human tissue; (5) the lack of adequate disposal techniques for incinerator fly ash and wash-water; (6) the contribution of emitted gases such as NO2, SO2 and HCL to smog, acid rain, and the formation of ozone, and the deleterious effects of these on human respiratory systems; (7) the effects and build-up in human tissue of other emitted organics such as benzene, toluene, polychlorinated biphenyls (PCBs), alkanes, alcohols, and phenols; (8) lack of pollution-control and real-time efficiency-monitoring equipment in existing installations. The inability of regulatory bodies historically to ensure compliance with emission standards is discussed, and a concluding opinion is offered that it is inadvisable to engage in new incinerator construction with present knowledge and conditions.

Impact of elevated CO2, water table, and temperature changes on CO2 and CH4 fluxes from arctic tundra soils

NASA Astrophysics Data System (ADS)

Zona, Donatella; Haynes, Katherine; Deutschman, Douglas; Bryant, Emma; McEwing, Katherine; Davidson, Scott; Oechel, Walter

2015-04-01

Large uncertainties still exist on the response of tundra C emissions to future climate due, in part, to the lack of understanding of the interactive effects of potentially controlling variables on C emissions from Arctic ecosystems. In this study we subjected 48 soil cores (without active vegetation) from dominant arctic wetland vegetation types, to a laboratory manipulation of elevated atmospheric CO2, elevated temperature, and altered water table, representing current and future conditions in the Arctic for two growing seasons. To our knowledge this experiment comprised the most extensively replicated manipulation of intact soil cores in the Arctic. The hydrological status of the soil was the most dominant control on both soil CO2 and CH4 emissions. Despite higher soil CO2 emission occurring in the drier plots, substantial CO2 respiration occurred under flooded conditions, suggesting significant anaerobic respirations in these arctic tundra ecosystems. Importantly, a critical control on soil CO2 and CH4 fluxes was the original vascular plant cover. The dissolved organic carbon (DOC) concentration was correlated with cumulative CH4 emissions but not with cumulative CO2 suggesting C quality influenced CH4 production but not soil CO2 emissions. An interactive effect between increased temperature and elevated CO2 on soil CO2 emissions suggested a potential shift of the soils microbial community towards more efficient soil organic matter degraders with warming and elevated CO2. Methane emissions did not decrease over the course of the experiment, even with no input from vegetation. This result indicated that CH4 emissions are not carbon limited in these C rich soils. Overall CH4 emissions represented about 49% of the sum of total C (C-CO2 + C-CH4) emission in the wet treatments, and 15% in the dry treatments, representing a dominant component of the overall C balance from arctic soils.

Present and future emissions of air pollutants in China:. SO 2, NO x, and CO

NASA Astrophysics Data System (ADS)

Streets, D. G.; Waldhoff, S. T.

As part of the CHINA-MAP program, sponsored by the US National Aeronautics and Space Administration, regional inventories of air pollutants emitted in China are being characterized, in order that the atmospheric chemistry over China can be more fully understood and the resulting ambient concentrations in Chinese cities and the deposition levels to Chinese ecosystems be determined with better confidence. This paper presents estimates of emissions of three of the major air pollutants in China: sulfur dioxide (SO 2), nitrogen oxides (NO x), and carbon monoxide (CO). Emissions are estimated for each of the 29 regions of China covered by the RAINS-ASIA simulation model, including Hong Kong and Taiwan. All sectors of the Chinese economy are considered, including the combustion of biofuels in rural homes. Data for 1990 and 1995 are presented, as well as two projections for the year 2020 under alternative assumptions about levels of environmental control. Sulfur dioxide emissions are projected to increase from 25.2 mt in 1995 to 30.6 mt in 2020, provided emission controls are implemented on major power plants; if this does not happen, emissions could increase to as much as 60.7 mt by 2020. Emissions of nitrogen oxides are projected to increase from 12.0 mt in 1995 to somewhere in the range of 26.6-29.7 mt by 2020, with little in the way of pollution controls or other emission reduction measures in place. Emissions of carbon monoxide are projected to decline from 115 mt in 1995 to 96.8 mt in 2020, due to more efficient combustion techniques, especially in the transportation sector; if these measures are not realized, carbon monoxide emissions could increase to 130 mt by 2020. Emissions of all three species are concentrated in the populated and industrialized areas of China: the Northeastern Plain, the East Central and Southeastern provinces, and the Sichuan Basin.

Methane, Black Carbon, and Ethane Emissions from Natural Gas Flares in the Bakken Shale, North Dakota.

PubMed

Gvakharia, Alexander; Kort, Eric A; Brandt, Adam; Peischl, Jeff; Ryerson, Thomas B; Schwarz, Joshua P; Smith, Mackenzie L; Sweeney, Colm

2017-05-02

Incomplete combustion during flaring can lead to production of black carbon (BC) and loss of methane and other pollutants to the atmosphere, impacting climate and air quality. However, few studies have measured flare efficiency in a real-world setting. We use airborne data of plume samples from 37 unique flares in the Bakken region of North Dakota in May 2014 to calculate emission factors for BC, methane, ethane, and combustion efficiency for methane and ethane. We find no clear relationship between emission factors and aircraft-level wind speed or between methane and BC emission factors. Observed median combustion efficiencies for methane and ethane are close to expected values for typical flares according to the US EPA (98%). However, we find that the efficiency distribution is skewed, exhibiting log-normal behavior. This suggests incomplete combustion from flares contributes almost 1/5 of the total field emissions of methane and ethane measured in the Bakken shale, more than double the expected value if 98% efficiency was representative. BC emission factors also have a skewed distribution, but we find lower emission values than previous studies. The direct observation for the first time of a heavy-tail emissions distribution from flares suggests the need to consider skewed distributions when assessing flare impacts globally.

Achieving lower nitrogen balance and higher nitrogen recovery efficiency reduces nitrous oxide emissions in North America’s maize cropping systems

USDA-ARS?s Scientific Manuscript database

Few studies have assessed the common, yet unproven, hypothesis that an increase of plant nitrogen (N) uptake and/or recovery efficiency (NRE) will reduce nitrous oxide (N2O) emission during crop production. Understanding the relationships between N2O emissions and crop N uptake and use efficiency p...

Short tests to couple N₂O emission mitigation and nitrogen removal strategies for landfill leachate recirculation.

PubMed

Wu, Dong; Wang, Chao; Dolfing, Jan; Xie, Bing

2015-04-15

Landfills implemented with onsite leachate recirculation can efficiently remove pollutants, but currently they are reckoned as N2O emission hot spots. In this project, we evaluated the relationship between N2O emission and nitrogen (N) removal efficiency with different types of leachate recirculated. Nitrate supplemented leachate showed low N2O emission rates with the highest N removal efficiency (~70%), which was equivalent to ~1% nitrogen emitted as N2O. Although in nitrite containing leachates' N removal efficiencies also reached to ~60%, their emitted N2O comprised ~40% of total removed nitrogen. Increasing nitrogen load promoted N2O emission and N removal efficiency, except in ammonia type leachate. When the ratio of BOD to total nitrogen increased from 0.2 to 0.4, the N2O emission flux from nitrate supplemented leachate decreased from ~25 to <0.5 μg N/kg-soil·h. We argue prior to leachate in situ recirculation, sufficient pre-aeration is critical to mitigate N2O surges and simultaneously enhance nitrogen removal efficiency. Copyright © 2015 Elsevier B.V. All rights reserved.

N use efficiencies and N2O emissions in two contrasting, biochar amended soils under winter wheat—cover crop—sorghum rotation

NASA Astrophysics Data System (ADS)

Hüppi, Roman; Neftel, Albrecht; Lehmann, Moritz F.; Krauss, Maike; Six, Johan; Leifeld, Jens

2016-08-01

Biochar, a carbon-rich, porous pyrolysis product of organic residues, is evaluated as an option to tackle major problems of the global food system. Applied to soil, biochar can sequester carbon and have beneficial effects on nitrogen (N) cycling, thereby enhancing crop yields and reducing nitrous oxide (N2O) emissions. There is little understanding of the underlying mechanisms, but many experiments indicated increased yields and manifold changes in N transformation, suggesting an increase in N use efficiency. Biochar’s effects can be positive in extensively managed tropical agriculture, however less is known about its use in temperate soils with intensive fertilisation. We tested the effect of slow pyrolysis wood chip biochar on N use efficiency, crop yields and N2O emissions in a lysimeter system with two soil types (sandy loamy Cambisol and silty loamy Luvisol) in a winter wheat—cover crop—sorghum rotation. 15N-labelled ammonium nitrate fertiliser (170 kg N ha-1 in 3 doses, 10% 15N) was applied to the first crop to monitor its fate in three ecosystem components (plants, soil, leachate). Green rye was sown as cover crop to keep the first year’s fertiliser N for the second year’s sorghum crop (fertilised with 110 kg N ha-1 in two doses and natural abundance 15N). We observed no effects of biochar on N fertiliser use efficiency, yield or N uptake for any crop. Biochar reduced leaching by 43 ± 19% but only towards the end of the experiment with leaching losses being generally low. For both soils N2O emissions were reduced by 15 ± 4% with biochar compared to the control treatments. Our results indicate that application of the chosen biochar induces environmental benefits in terms of N2O emission and N leaching but does not substantially affect the overall N cycle and hence crop performance in the analyzed temperate crop rotation.

Hypergolic oxidizer and fuel scrubber emissions

NASA Technical Reports Server (NTRS)

Parrish, Clyde F.; Barile, Ronald G.; Curran, Dan; Hodge, Tim; Lueck, Dale E.; Young, Rebecca C.

1995-01-01

Hypergolic fuels and oxidizer are emitted to the environment during fueling and deservicing shuttle and other spacecraft. Such emissions are difficult to measure due to the intermittent purge flow and to the presence of suspended scrubber liquor. A new method for emissions monitoring was introduced in a previous paper. This paper is a summary of the results of a one-year study of shuttle launch pads and orbiter processing facilities (OPF's) which proved that emissions can be determined from field scrubbers without direct measurement of vent flow rate and hypergol concentration. This new approach is based on the scrubber efficiency, which was measured during normal operations, and on the accumulated weight of hypergol captured in the scrubber liquor, which is part of the routine monitoring data of scrubber liquors. To validate this concept, three qualification tests were performed, logs were prepared for each of 16 hypergol scrubbers at KSC, the efficiencies of KSC scrubbers were measured during normal operations, and an estimate of the annual emissions was made based on the efficiencies and the propellant buildup data. The results have confirmed that the emissions from the KSC scrubbers can be monitored by measuring the buildup of hypergol propellant in the liquor, and then using the appropriate efficiency to calculate the emissions. There was good agreement between the calculated emissions based on outlet concentration and flow rate, and the emissions calculated from the propellant buildup and efficiency. The efficiencies of 12 KSC scrubbers, measured under actual servicing operations and special test conditions, were assumed to be valid for all subsequent operations until a significant change in hardware occurred. An estimate of the total emissions from 16 scrubbers for three years showed that 0.3 kg/yr of fuel and 234 kg/yr of oxidizer were emitted.

Bright Single InAsP Quantum Dots at Telecom Wavelengths in Position-Controlled InP Nanowires: The Role of the Photonic Waveguide.

PubMed

Haffouz, Sofiane; Zeuner, Katharina D; Dalacu, Dan; Poole, Philip J; Lapointe, Jean; Poitras, Daniel; Mnaymneh, Khaled; Wu, Xiaohua; Couillard, Martin; Korkusinski, Marek; Schöll, Eva; Jöns, Klaus D; Zwiller, Valery; Williams, Robin L

2018-05-09

We report on the site-selected growth of bright single InAsP quantum dots embedded within InP photonic nanowire waveguides emitting at telecom wavelengths. We demonstrate a dramatic dependence of the emission rate on both the emission wavelength and the nanowire diameter. With an appropriately designed waveguide, tailored to the emission wavelength of the dot, an increase in the count rate by nearly 2 orders of magnitude (0.4 to 35 kcps) is obtained for quantum dots emitting in the telecom O-band, showing high single-photon purity with multiphoton emission probabilities down to 2%. Using emission-wavelength-optimized waveguides, we demonstrate bright, narrow-line-width emission from single InAsP quantum dots with an unprecedented tuning range of 880 to 1550 nm. These results pave the way toward efficient single-photon sources at telecom wavelengths using deterministically grown InAsP/InP nanowire quantum dots.

Collection of ultrafine diesel particulate matter (DPM) in cylindrical single-stage wet electrostatic precipitators.

PubMed

Saiyasitpanich, Phirun; Keener, Tim C; Lu, Mingming; Khang, Soon-Jai; Evans, Douglas E

2006-12-15

Long-term exposures to diesel particulate matter (DPM) emissions are linked to increasing adverse human health effects due to the potential association of DPM with carcinogenicity. Current diesel vehicular particulate emission regulations are based solely upon total mass concentration, albeit it is the submicrometer particles that are highly respirable and the most detrimental to human health. In this study, experiments were performed with a tubular single-stage wet electrostatic precipitator (wESP) to evaluate its performance for the removal of number-based DPM emissions. A nonroad diesel generator utilizing a low sulfur diesel fuel (500 ppmw) operating under varying load conditions was used as a stationary DPM emission source. An electrical low-pressure impactor (ELPI) was used to quantify the number concentration distributions of diesel particles in the diluted exhaust gas at each tested condition. The wESP was evaluated with respect to different operational control parameters such as applied voltage, gas residence time, etc., to determine their effect on overall collection efficiency, as well as particle size dependent collection efficiency. The results show that the total DPM number concentrations in the untreated diesel exhaust are in the magnitude of approximately108/cm(3) at all engine loads with the particle diameter modes between 20 and 40 nm. The measured collection efficiency of the wESP operating at 70 kV based on total particle numbers was 86% at 0 kW engine load and the efficiency decreased to 67% at 75 kW due to a decrease in gas residence time and an increase in particle concentrations. At a constant wESP voltage of 70 kV and at 75 kW engine load, the variation of gas residence time within the wESP from approximately 0.1 to approximately 0.4 s led to a substantial increase in the collection efficiency from 67% to 96%. In addition, collection efficiency was found to be directly related to the applied voltage, with increasing collection efficiency measured for increases in applied voltage. The collection efficiency based on particle size had a minimum for sizes between 20 and 50 nm, but at optimal wESP operating conditions it was possible to remove over 90% of all particle sizes. A comparison of measured and calculated collection efficiencies reveals that the measured values are significantly higher than the predicted values based on the well-known Deutsch equation.

Exhaust emission control and diagnostics

DOEpatents

Mazur, Christopher John; Upadhyay, Devesh

2006-11-14

A diesel engine emission control system uses an upstream oxidation catalyst and a downstream SCR catalyst to reduce NOx in a lean exhaust gas environment. The engine and upstream oxidation catalyst are configured to provide approximately a 1:1 ratio of NO to NO2 entering the downstream catalyst. In this way, the downstream catalyst is insensitive to sulfur contamination, and also has improved overall catalyst NOx conversion efficiency. Degradation of the system is determined when the ratio provided is no longer near the desired 1:1 ratio. This condition is detected using measurements of engine operating conditions such as from a NOx sensor located downstream of the catalysts. Finally, control action to adjust an injected amount of reductant in the exhaust gas based on the actual NO to NO2 ratio upstream of the SCR catalyst and downstream of the oxidation catalyst.

Historical Trends in PM 2.5-Related Premature Mortality during 1990$-$2010 across the Northern Hemisphere

DOE PAGES

Wang, Jiandong; Xing, Jia; Mathur, Rohit; ...

2016-08-19

Air quality across the northern hemisphere over the past two decades has witnessed dramatic changes, with continuous improvement in developed countries in North America and Europe, but a contrasting sharp deterioration in developing regions of Asia. Objective: This study investigates the historical trend in the long-term exposure to PM 2.5 and PM 2.5-related premature mortality (PM 2.5-mortality) and its response to changes in emission that occurred during 1990-2010 across the northern hemisphere. Implications for future trends in human exposure to air pollution in both developed and developing regions of the world are discussed. Methods: We employed the integrated exposure-response modelmore » developed by Health Effects Institute to estimate the PM 2.5-mortality. The 1990-2010 annual-average PM 2.5 concentrations were obtained from the simulations using WRF-CMAQ model. Emission mitigation efficiencies of SO 2, NO x, NH 3 and primary PM are estimated from the PM 2.5-mortality responses to the emission variations. Results: Estimated PM 2.5-mortalities in East Asia and South Asia increased by 21% and 85% respectively, from 866,000 and 578,000 in 1990, to 1,048,000 and 1,068,000 in 2010. PM2.5-mortalities in developed regions, i.e., Europe and high-income North America decreased substantially by 67% and 58% respectively. Conclusions: Over the past two decades, correlations between population and PM 2.5 have become weaker in Europe and North America due to air pollution controls but stronger in East Asia due to deteriorating air quality. Mitigation of primary PM appears to be the most efficient way for increasing health benefits, i.e., providing the largest mortality reduction per unit emissions. However, reductions in emissions of NH 3 are needed to maximize the effectiveness of NO x emission controls.« less

Historical Trends in PM 2.5-Related Premature Mortality during 1990$-$2010 across the Northern Hemisphere

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Jiandong; Xing, Jia; Mathur, Rohit

Air quality across the northern hemisphere over the past two decades has witnessed dramatic changes, with continuous improvement in developed countries in North America and Europe, but a contrasting sharp deterioration in developing regions of Asia. Objective: This study investigates the historical trend in the long-term exposure to PM 2.5 and PM 2.5-related premature mortality (PM 2.5-mortality) and its response to changes in emission that occurred during 1990-2010 across the northern hemisphere. Implications for future trends in human exposure to air pollution in both developed and developing regions of the world are discussed. Methods: We employed the integrated exposure-response modelmore » developed by Health Effects Institute to estimate the PM 2.5-mortality. The 1990-2010 annual-average PM 2.5 concentrations were obtained from the simulations using WRF-CMAQ model. Emission mitigation efficiencies of SO 2, NO x, NH 3 and primary PM are estimated from the PM 2.5-mortality responses to the emission variations. Results: Estimated PM 2.5-mortalities in East Asia and South Asia increased by 21% and 85% respectively, from 866,000 and 578,000 in 1990, to 1,048,000 and 1,068,000 in 2010. PM2.5-mortalities in developed regions, i.e., Europe and high-income North America decreased substantially by 67% and 58% respectively. Conclusions: Over the past two decades, correlations between population and PM 2.5 have become weaker in Europe and North America due to air pollution controls but stronger in East Asia due to deteriorating air quality. Mitigation of primary PM appears to be the most efficient way for increasing health benefits, i.e., providing the largest mortality reduction per unit emissions. However, reductions in emissions of NH 3 are needed to maximize the effectiveness of NO x emission controls.« less

Thermodynamic Modeling and Dispatch of Distributed Energy Technologies including Fuel Cell -- Gas Turbine Hybrids

NASA Astrophysics Data System (ADS)

McLarty, Dustin Fogle

Distributed energy systems are a promising means by which to reduce both emissions and costs. Continuous generators must be responsive and highly efficiency to support building dynamics and intermittent on-site renewable power. Fuel cell -- gas turbine hybrids (FC/GT) are fuel-flexible generators capable of ultra-high efficiency, ultra-low emissions, and rapid power response. This work undertakes a detailed study of the electrochemistry, chemistry and mechanical dynamics governing the complex interaction between the individual systems in such a highly coupled hybrid arrangement. The mechanisms leading to the compressor stall/surge phenomena are studied for the increased risk posed to particular hybrid configurations. A novel fuel cell modeling method introduced captures various spatial resolutions, flow geometries, stack configurations and novel heat transfer pathways. Several promising hybrid configurations are analyzed throughout the work and a sensitivity analysis of seven design parameters is conducted. A simple estimating method is introduced for the combined system efficiency of a fuel cell and a turbine using component performance specifications. Existing solid oxide fuel cell technology is capable of hybrid efficiencies greater than 75% (LHV) operating on natural gas, and existing molten carbonate systems greater than 70% (LHV). A dynamic model is calibrated to accurately capture the physical coupling of a FC/GT demonstrator tested at UC Irvine. The 2900 hour experiment highlighted the sensitivity to small perturbations and a need for additional control development. Further sensitivity studies outlined the responsiveness and limits of different control approaches. The capability for substantial turn-down and load following through speed control and flow bypass with minimal impact on internal fuel cell thermal distribution is particularly promising to meet local demands or provide dispatchable support for renewable power. Advanced control and dispatch heuristics are discussed using a case study of the UCI central plant. Thermal energy storage introduces a time horizon into the dispatch optimization which requires novel solution strategies. Highly efficient and responsive generators are required to meet the increasingly dynamic loads of today's efficient buildings and intermittent local renewable wind and solar power. Fuel cell gas turbine hybrids will play an integral role in the complex and ever-changing solution to local electricity production.

Textured carbon on copper: A novel surface with extremely low secondary electron emission characteristics

NASA Technical Reports Server (NTRS)

Curren, A. N.; Jensen, K. A.

1985-01-01

Experimentally determined values of true secondary electron emission and relative values of reflected primary electron yield for a range of primary electron beam energies and beam impingement angles are presented for a series of novel textured carbon surfaces on copper substrates. (All copper surfaces used in this study were oxygen-free, high-conductivity grade). The purpose of this investigation is to provide information necessary to develop high-efficiency multistage depressed collectors (MDC's) for microwave amplifier traveling-wave tubes (TWT's) for communications and aircraft applications. To attain the highest TWT signal quality and overall efficiency, the MDC electrode surface must have low secondary electron emission characteristics. While copper is the material most commonly used for MDC electrodes, it exhibits relatively high levels of secondary electron emission unless its surface is treated for emission control. The textured carbon surface on copper substrate described in this report is a particularly promising candidate for the MDC electrode application. Samples of textured carbon surfaces on copper substrates typical of three different levels of treatment are prepared and tested for this study. The materials are tested at primary electron beam energies of 200 to 2000 eV and at direct (0 deg) to near-grazing (85 deg) beam impingement angles. True secondary electron emission and relative reflected primary electron yield characteristics of the textured surfaces are compared with each other and with those of untreated copper. All the textured carbon surfaces on copper substrate tested exhibited sharply lower secondary electron emission characteristics than those of an untreated copper surface.

Nitrogen source effects on soil nitrous oxide emissions from strip-till corn.

PubMed

Halvorson, Ardell D; Del Grosso, Stephen J; Jantalia, Claudia Pozzi

2011-01-01

Nitrogen (N) application to crops generally results in increased nitrous oxide (NO) emissions. Commercially available, enhanced-efficiency N fertilizers were evaluated for their potential to reduce NO emissions from a clay loam soil compared with conventionally used granular urea and urea-ammonium nitrate (UAN) fertilizers in an irrigated strip-till (ST) corn ( L.) production system. Enhanced-efficiency N fertilizers evaluated were a controlled-release, polymer-coated urea (ESN), stabilized urea, and UAN products containing nitrification and urease inhibitors (SuperU and UAN+AgrotainPlus), and UAN containing a slow-release N source (Nfusion). Each N source was surface-band applied (202 kg N ha) at corn emergence and watered into the soil the next day. A subsurface-band ESN treatment was included. Nitrous oxide fluxes were measured during two growing seasons using static, vented chambers and a gas chromatograph analyzer. All N sources had significantly lower growing season NO emissions than granular urea, with UAN+AgrotainPlus and UAN+Nfusion having lower emissions than UAN. Similar trends were observed when expressing NO emissions on a grain yield and N uptake basis. Loss of NO-N per kilogram of N applied was <0.8% for all N sources. Corn grain yields were not different among N sources but greater than treatments with no N applied. Selection of N fertilizer source can be a mitigation practice for reducing NO emissions in strip-till, irrigated corn in semiarid areas. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Innovative Adaptive Control Method Demonstrated for Active Suppression of Instabilities in Engine Combustors

NASA Technical Reports Server (NTRS)

Kopasakis, George

2005-01-01

This year, an improved adaptive-feedback control method was demonstrated that suppresses thermoacoustic instabilities in a liquid-fueled combustor of a type used in aircraft engines. Extensive research has been done to develop lean-burning (low fuel-to-air ratio) combustors that can reduce emissions throughout the mission cycle to reduce the environmental impact of aerospace propulsion systems. However, these lean-burning combustors are susceptible to thermoacoustic instabilities (high-frequency pressure waves), which can fatigue combustor components and even downstream turbine blades. This can significantly decrease the safe operating life of the combustor and turbine. Thus, suppressing the thermoacoustic combustor instabilities is an enabling technology for meeting the low-emission goals of the NASA Ultra-Efficient Engine Technology (UEET) Project.

Fall 2016 Solicitation Projects Website Info

DOE Office of Scientific and Technical Information (OSTI.GOV)

Diachin, L.

Spark-ignition engines are the backbone behind people transportation around the world. The efficiency of spark-ignition engines is limited in practice by variations between engine cycles and cylinders within an engine that result from the manufacturing processes/tolerances. These variations impact knock limits and dilution tolerance, which results in more conservative settings for design and calibration settings, such as compression ratio, valve timing, and exhaust gas recirculation rates. Engine variations also have a significant impact on emissions generation, which can have a secondary impact on efficiency. A deeper understanding of the relative importance of these variations and their interactions on the chargemore » preparation process can guide future decisions on machining tolerances and control strategies. This project will develop simulation tools and methodology to include the effects of some key manufacturing tolerances and their impact on engine performance and emissions.« less

Possibility of reducing CO2 emissions from internal combustion engines

NASA Astrophysics Data System (ADS)

Drabik, Dawid; Mamala, Jarosław; Śmieja, Michał; Prażnowski, Krzysztof

2017-10-01

Article defines on the possibility of reduction CO2 of the internal combustion engine and presents the analysis based on originally conducted studies. The increase in overall engine efficiency is sought after by all engineers dealing with engine construction, one of the major ways to reduce CO2 emissions is to increase the compression ratio. The application of the compression ratio that has been increased constructional in the engine will, on one hand, bring about the increase in the theoretical efficiency, but, on the other hand, require a system for pressure control at a higher engine load in order to prevent engine knocking. For the purposes of the article there was carried out a number of studies and compiled results, and on their basis determined what have a major impact on the reducing CO2.

European type-approval test procedure for evaporative emissions from passenger cars against real-world mobility data from two Italian provinces.

PubMed

Martini, Giorgio; Paffumi, Elena; De Gennaro, Michele; Mellios, Giorgos

2014-07-15

This paper presents an evaluation of the European type-approval test procedure for evaporative emissions from passenger cars based on real-world mobility data. The study relies on two large databases of driving patterns from conventional fuel vehicles collected by means of on-board GPS systems in the Italian provinces of Modena and Firenze. Approximately 28,000 vehicles were monitored, corresponding to approximately 36 million kilometres over a period of one month. The driving pattern of each vehicle was processed to derive the relation between trip length and parking duration, and the rate of occurrence of parking events against multiple evaporative cycles, defined on the basis of the type-approval test procedure as 12-hour diurnal time windows. These results are used as input for an emission simulation model, which calculates the total evaporative emissions given the characteristics of the evaporative emission control system of the vehicle and the ambient temperature conditions. The results suggest that the evaporative emission control system, fitted to the vehicles from Euro 3 step and optimised for the current type-approval test procedure, could not efficiently work under real-world conditions, resulting in evaporative emissions well above the type-approval limit, especially for small size vehicles and warm climate conditions. This calls for a revision of the type-approval test procedure in order to address real-world evaporative emissions. Copyright © 2014. Published by Elsevier B.V.

40 CFR 60.614 - Test methods and procedures.

Code of Federal Regulations, 2012 CFR

2012-07-01

... or TOC (less methane and ethane) reduction efficiency shall be prior to the inlet of the control... TOC (minus methane and ethane), dry basis, ppm by volume. %O2d=Concentration of O2, dry basis, percent.... (ii) The emission reduction (R) of TOC (minus methane and ethane) shall be determined using the...

40 CFR 60.664 - Test methods and procedures.

Code of Federal Regulations, 2012 CFR

2012-07-01

... (less methane and ethane) reduction efficiency shall be prior to the inlet of the control device and... methane and ethane), dry basis, ppm by volume. %O2d=Concentration of O2, dry basis, percent by volume. (4... emission reduction (R) of TOC (minus methane and ethane) shall be determined using the following equation...

Minimize emissions and improve efficacy with low permeability tarp and deep injection in soil fumigation

USDA-ARS?s Scientific Manuscript database

Soil fumigation targets high pest control efficiency and low environmental impact. Earlier field data show that most fumigated treatments provided 100% kill for plant parasitic nematodes in the soil above 3 ft depth, but not below due to insufficient fumigant delivery. A fumigation trial was conduct...

40 CFR Appendix A to Part 75 - Specifications and Test Procedures

Code of Federal Regulations, 2012 CFR

2012-07-01

... appendix. RE = Expected average design removal efficiency of control equipment (%). 2.1.1.3Span Value(s... 40 Protection of Environment 17 2012-07-01 2012-07-01 false Specifications and Test Procedures A... (CONTINUED) CONTINUOUS EMISSION MONITORING Pt. 75, App. A Appendix A to Part 75—Specifications and Test...

40 CFR Appendix A to Part 75 - Specifications and Test Procedures

Code of Federal Regulations, 2013 CFR

2013-07-01

... appendix. RE = Expected average design removal efficiency of control equipment (%). 2.1.1.3Span Value(s... 40 Protection of Environment 17 2013-07-01 2013-07-01 false Specifications and Test Procedures A... (CONTINUED) CONTINUOUS EMISSION MONITORING Pt. 75, App. A Appendix A to Part 75—Specifications and Test...

NREL Fuels and Engines Research: Maximizing Vehicle Efficiency and

Science.gov Websites

Laboratory, we analyze the effects of fuel chemistry on ignition and the potential emissions impacts. Our lab research. It can be used to investigate fuel chemistry effects on current and near-term engine technology , independent control allows for deeper interrogation of fuel effects on future-generation engine strategies

40 CFR 60.4310 - What types of operations are exempt from these standards of performance?

Code of Federal Regulations, 2011 CFR

2011-07-01

... turbine emission control techniques and combustion turbine efficiency improvements are exempt from the NOX... Standards of Performance for Stationary Combustion Turbines Applicability § 60.4310 What types of operations are exempt from these standards of performance? (a) Emergency combustion turbines, as defined in § 60...

40 CFR 60.4310 - What types of operations are exempt from these standards of performance?

Code of Federal Regulations, 2014 CFR

2014-07-01

... turbine emission control techniques and combustion turbine efficiency improvements are exempt from the NOX... Standards of Performance for Stationary Combustion Turbines Applicability § 60.4310 What types of operations are exempt from these standards of performance? (a) Emergency combustion turbines, as defined in § 60...

40 CFR 63.4181 - What definitions apply to this subpart?

Code of Federal Regulations, 2011 CFR

2011-07-01

... commercial or industrial HVAC systems. Manufacturer's formulation data means data on a material (such as a... capture system efficiency means the portion (expressed as a percentage) of the pollutants from an emission source that is delivered to an add-on control device. Capture system means one or more capture devices...

40 CFR 63.4181 - What definitions apply to this subpart?

Code of Federal Regulations, 2010 CFR

2010-07-01

... commercial or industrial HVAC systems. Manufacturer's formulation data means data on a material (such as a... capture system efficiency means the portion (expressed as a percentage) of the pollutants from an emission source that is delivered to an add-on control device. Capture system means one or more capture devices...

40 CFR 63.305 - Alternative standards for coke oven doors equipped with sheds.

Code of Federal Regulations, 2013 CFR

2013-07-01

... SOURCE CATEGORIES National Emission Standards for Coke Oven Batteries § 63.305 Alternative standards for coke oven doors equipped with sheds. (a) The owner or operator of a new or existing coke oven battery... the efficiency of the control device for removal of particulate matter by conducting measurements at...

40 CFR 63.305 - Alternative standards for coke oven doors equipped with sheds.

Code of Federal Regulations, 2010 CFR

2010-07-01

... SOURCE CATEGORIES National Emission Standards for Coke Oven Batteries § 63.305 Alternative standards for coke oven doors equipped with sheds. (a) The owner or operator of a new or existing coke oven battery... the efficiency of the control device for removal of particulate matter by conducting measurements at...

40 CFR 63.305 - Alternative standards for coke oven doors equipped with sheds.

Code of Federal Regulations, 2014 CFR

2014-07-01

... SOURCE CATEGORIES National Emission Standards for Coke Oven Batteries § 63.305 Alternative standards for coke oven doors equipped with sheds. (a) The owner or operator of a new or existing coke oven battery... the efficiency of the control device for removal of particulate matter by conducting measurements at...

40 CFR 63.305 - Alternative standards for coke oven doors equipped with sheds.

Code of Federal Regulations, 2012 CFR

2012-07-01

... SOURCE CATEGORIES National Emission Standards for Coke Oven Batteries § 63.305 Alternative standards for coke oven doors equipped with sheds. (a) The owner or operator of a new or existing coke oven battery... the efficiency of the control device for removal of particulate matter by conducting measurements at...

40 CFR 63.305 - Alternative standards for coke oven doors equipped with sheds.

Code of Federal Regulations, 2011 CFR

2011-07-01

... SOURCE CATEGORIES National Emission Standards for Coke Oven Batteries § 63.305 Alternative standards for coke oven doors equipped with sheds. (a) The owner or operator of a new or existing coke oven battery... the efficiency of the control device for removal of particulate matter by conducting measurements at...

Mixed-Potential NO x and NH 3 Sensors Fabricated by Commercial Manufacturing Methods [Mixed-Potential Sensors NO x and NH 3 Fabricated by Commercial Manufacturing Methods

DOE PAGES

Kreller, Cortney R.; Spernjak, Dusan; Li, Wenxia; ...

2014-08-12

Meeting EPA Tier 3 emissions reduction requirements while simultaneously increasing fuel economy to meet new CAFE standards will require optimization of advanced combustion strategies and emissions control technologies. There is an immediate need for suitable exhaust gas sensor technologies to monitor internal combustion engine tailpipe emissions and to control and maintain efficient operation of the engine and exhaust after treatment systems. NH 3, NO x, and HC sensors could enable onboard diagnostics and combustion control in lean-burn engines, analogous to the role of O 2 sensors in stoichiometric burn engines. Commercial manufacturing methods have been used to fabricate self-heated mixed-potentialmore » sensors in a planar automotive configuration. By altering materials composition and operating conditions, we are able to obtain sensitivity/selectivity to each NH 3, NO x and HCs. In addition, these devices exhibit stable performance over months of testing as a result of the stable morphology of the electrode/electrolyte/gas three-phase interface.« less

Materials for Sustainable Energy

NASA Astrophysics Data System (ADS)

Crabtree, George

2009-03-01

The global dependence on fossil fuels for energy is among the greatest challenges facing our economic, social and political future. The uncertainty in the cost and supply of oil threatens the global economy and energy security, the pollution of fossil combustion threatens human health, and the emission of greenhouse gases threatens global climate. Meeting the demand for double the current global energy use in the next 50 years without damaging our economy, security, environment or climate requires finding alternative sources of energy that are clean, abundant, accessible and sustainable. The transition to greater sustainability involves tapping unused energy flows such as sunlight and wind, producing electricity without carbon emissions from clean coal and high efficiency nuclear power plants, and using energy more efficiently in solid-state lighting, fuel cells and transportation based on plug-in hybrid and electric cars. Achieving these goals requires creating materials of increasing complexity and functionality to control the transformation of energy between light, electrons and chemical bonds. Challenges and opportunities for developing the complex materials and controlling the chemical changes that enable greater sustainability will be presented.

Controlled synthesis of Eu 2+ and Eu 3+ doped ZnS quantum dots and their photovoltaic and magnetic properties

DOE PAGES

Horoz, Sabit; Yakami, Baichhabi; Poudyal, Uma; ...

2016-04-27

Eu-doped ZnS quantum dots (QDs) have been synthesized by wet-chemical method and found to form in zinc blende (cubic) structure. Both Eu 2+ and Eu 3+ doped ZnS can be controllably synthesized. The Eu 2+ doped ZnS QDs show broad photoluminescence emission peak around 512 nm, which is from the Eu2+ intra-ion transition of 4f 6d1 – 4f 7, while the Eu 3+ doped samples exhibit narrow emission lines characteristic of transitions between the 4f levels. The investigation of the magnetic properties shows that the Eu 3+ doped samples exhibit signs of ferromagnetism, on the other hand, Eu 2+ dopedmore » samples are paramagnetic of Curie-Weiss type. The incident photon to electron conversion efficiency is increased with the Eu doping, which suggests the QD solar cell efficiency can be enhanced by Eu doping due to widened absorption windows. This is an attractive approach to utilize benign and environmentally friendly wide band gap ZnS QDs in solar cell technology.« less

Control of the low-load region in partially premixed combustion

NASA Astrophysics Data System (ADS)

Ingesson, Gabriel; Yin, Lianhao; Johansson, Rolf; Tunestal, Per

2016-09-01

Partially premixed combustion (PPC) is a low temperature, direct-injection combustion concept that has shown to give promising emission levels and efficiencies over a wide operating range. In this concept, high EGR ratios, high octane-number fuels and early injection timings are used to slow down the auto-ignition reactions and to enhance the fuel and are mixing before the start of combustion. A drawback with this concept is the combustion stability in the low-load region where a high octane-number fuel might cause misfire and low combustion efficiency. This paper investigates the problem of low-load PPC controller design for increased engine efficiency. First, low-load PPC data, obtained from a multi-cylinder heavy- duty engine is presented. The data shows that combustion efficiency could be increased by using a pilot injection and that there is a non-linearity in the relation between injection and combustion timing. Furthermore, intake conditions should be set in order to avoid operating points with unfavourable global equivalence ratio and in-cylinder temperature combinations. Model predictive control simulations were used together with a calibrated engine model to find a gas-system controller that fulfilled this task. The findings are then summarized in a suggested engine controller design. Finally, an experimental performance evaluation of the suggested controller is presented.

PM10 emission efficiency for agricultural soils: Comparing a wind tunnel, a dust generator, and the open-air plot

NASA Astrophysics Data System (ADS)

Avecilla, Fernando; Panebianco, Juan E.; Mendez, Mariano J.; Buschiazzo, Daniel E.

2018-06-01

The PM10 emission efficiency of soils has been determined through different methods. Although these methods imply important physical differences, their outputs have never been compared. In the present study the PM10 emission efficiency was determined for soils through a wide range of textures, using three typical methodologies: a rotary-chamber dust generator (EDG), a laboratory wind tunnel on a prepared soil bed, and field measurements on an experimental plot. Statistically significant linear correlation was found (p < 0.05) between the PM10 emission efficiency obtained from the EDG and wind tunnel experiments. A significant linear correlation (p < 0.05) was also found between the PM10 emission efficiency determined both with the wind tunnel and the EDG, and a soil texture index (%sand + %silt)/(%clay + %organic matter) that reflects the effect of texture on the cohesion of the aggregates. Soils with higher sand content showed proportionally less emission efficiency than fine-textured, aggregated soils. This indicated that both methodologies were able to detect similar trends regarding the correlation between the soil texture and the PM10 emission. The trends attributed to soil texture were also verified for two contrasting soils under field conditions. However, differing conditions during the laboratory-scale and the field-scale experiments produced significant differences in the magnitude of the emission efficiency values. The causes of these differences are discussed within the paper. Despite these differences, the results suggest that standardized laboratory and wind tunnel procedures are promissory methods, which could be calibrated in the future to obtain results comparable to field values, essentially through adjusting the simulation time. However, more studies are needed to extrapolate correctly these values to field-scale conditions.

40 CFR Table 4 to Subpart Kkkk of... - Operating Limits If Using the Emission Rate With Add-on Controls Option or the Control Efficiency...

Code of Federal Regulations, 2013 CFR

2013-07-01

... items in 2.a, 2.b, and 2.c of this table. 4. Carbon adsorber a. The total regeneration desorbing gas (e.g., steam or nitrogen) mass flow for each carbon bed regeneration cycle must not fall below the total regeneration desorbing gas mass flow limit established according to § 63.3546(d) or § 63.3556(d...

40 CFR Table 4 to Subpart Kkkk of... - Operating Limits If Using the Emission Rate With Add-on Controls Option or the Control Efficiency...

Code of Federal Regulations, 2011 CFR

2011-07-01

..., 2.b, and 2.c of this table. 4. Carbon adsorber a. The total regeneration desorbing gas (e.g., steam or nitrogen) mass flow for each carbon bed regeneration cycle must not fall below the total regeneration desorbing gas mass flow limit established according to § 63.3546(d) or § 63.3556(d). i. Measuring...

40 CFR Table 4 to Subpart Kkkk of... - Operating Limits If Using the Emission Rate With Add-on Controls Option or the Control Efficiency...

Code of Federal Regulations, 2014 CFR

2014-07-01

... items in 2.a, 2.b, and 2.c of this table. 4. Carbon adsorber a. The total regeneration desorbing gas (e.g., steam or nitrogen) mass flow for each carbon bed regeneration cycle must not fall below the total regeneration desorbing gas mass flow limit established according to § 63.3546(d) or § 63.3556(d...

40 CFR Table 4 to Subpart Kkkk of... - Operating Limits If Using the Emission Rate With Add-on Controls Option or the Control Efficiency...

Code of Federal Regulations, 2012 CFR

2012-07-01

... items in 2.a, 2.b, and 2.c of this table. 4. Carbon adsorber a. The total regeneration desorbing gas (e.g., steam or nitrogen) mass flow for each carbon bed regeneration cycle must not fall below the total regeneration desorbing gas mass flow limit established according to § 63.3546(d) or § 63.3556(d...

Spatial analysis on China's regional air pollutants and CO2 emissions: emission pattern and regional disparity

NASA Astrophysics Data System (ADS)

Dong, Liang; Liang, Hanwei

2014-08-01

China has suffered from serious air pollution and CO2 emission. Challenges of emission reduction policy not only come from technology advancement, but also generate from the fact that, China has pronounced disparity between regions, in geographical and socioeconomic. How to deal with regional disparity is important to achieve the reduction target effectively and efficiently. This research conducts a spatial analysis on the emission patterns of three air pollutants named SO2, NOx and PM2.5, and CO2, in China's 30 provinces, applied with spatial auto-correlation and multi regression modeling. We further analyze the regional disparity and inequity issues with the approach of Lorenz curve and Gini coefficient. Results highlight that: there is evident cluster effect for the regional air pollutants and CO2 emissions. While emission amount increases from western regions to eastern regions, the emission per GDP is in inverse trend. The Lorenz curve shows an even larger unequal distribution of GDP/emissions than GDP/capita in 30 regions. Certain middle and western regions suffers from a higher emission with lower GDP, which reveal the critical issue of emission leakage. Future policy making to address such regional disparity is critical so as to promote the emission control policy under the “equity and efficiency” principle.

Advanced Hybrid Particulate Collector Project Management Plan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, S.J.

As the consumption of energy increases, its impact on ambient air quality has become a significant concern. Recent studies indicate that fine particles from coal combustion cause health problems as well as atmospheric visibility impairment. These problems are further compounded by the concentration of hazardous trace elements such as mercury, cadmium, selenium, and arsenic in fine particles. Therefore, a current need exists to develop superior, but economical, methods to control emissions of fine particles. Since most of the toxic metals present in coal will be in particulate form, a high level of fine- particle collection appears to be the bestmore » method of overall air toxics control. However, over 50% of mercury and a portion of selenium emissions are in vapor form and cannot be collected in particulate control devices. Therefore, this project will focus on developing technology not only to provide ultrahigh collection efficiency of particulate air toxic emissions, but also to capture vapor- phase trace metals such as mercury and selenium. Currently, the primary state-of-the-art technologies for particulate control are fabric filters (baghouses) and electrostatic precipitators (ESPs). However, they both have limitations that prevent them from achieving ultrahigh collection of fine particulate matter and vapor-phase trace metals. The objective of this project is to develop a highly reliable advanced hybrid particulate collector (AHPC) that can provide > 99.99 % particulate collection efficiency for all particle sizes between 0.01 and 50 14m, is applicable for use with all U.S. coals, and is cost-0443competitive with existing technologies. Phase I of the project is organized into three tasks: Task I - Project Management, Reporting, and Subcontract Consulting Task 2 - Modeling, Design, and Construction of 200-acfm AHPC Model Task 3 - Experimental Testing and Subcontract Consulting« less

Heavy Vehicle Propulsion System Materials Program Semiannual Progress Report for April 2000 Through September 2000

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, DR

2000-12-11

The purpose of the Heavy Vehicle Propulsion System Materials Program is the development of materials: ceramics, intermetallics, metal alloys, and metal and ceramic coatings, to support the dieselization of class 1-3 trucks to realize a 35% fuel-economy improvement over current gasoline-fueled trucks and to support commercialization of fuel-flexible LE-55 low-emissions, high-efficiency diesel engines for class 7-8 trucks. The Office of Transportation Technologies, Office of Heavy Vehicle Technologies (OTT OHVT) has an active program to develop the technology for advantages LE-55 diesel engines with 55% efficiency and low emissions levels of 2.0 g/bhp-h NOx and 0.05 g/bhp-h particulates. The goal ismore » also for the LE-55 engine to run on natural gas with efficiency approaching that of diesel fuel. The LE-55 program is being completed in FY 1997 and, after approximately 10 years of effort, has largely met the program goals of 55% efficiency and low emissions. However, the commercialization of the LE-55 technology requires more durable materials than those that have been used to demonstrate the goals. Heavy Vehicle Propulsion System Materials will, in concert with the heavy duty diesel engine companies, develop the durable materials required to commercialize the LE-55 technologies. OTT OHVT also recognizes a significant opportunity for reduction in petroleum consumption by dieselization of pickup trucks, vans, and sport utility vehicles. Application of the diesel engine to class 1, 2, and 3 trucks is expected to yield a 35% increase in fuel economy per vehicle. The foremost barrier to diesel use in this market is emission control. Once an engine is made certifiable, subsequent challenges will be in cost; noise, vibration, and harshness (NVH); and performance. The design of advanced components for high-efficiency diesel engines has, in some cases, pushed the performance envelope for materials of construction past the point of reliable operation. Higher mechanical and tribological stresses and higher temperatures of advanced designs limit the engine designer; advanced materials allow the design of components that may operate reliably at higher stresses and temperatures, thus enabling more efficient engine designs. Advanced materials also offer the opportunity to improve the emissions, NVH, and performance of diesel engines for pickup trucks, vans, and sport utility vehicles.« less

Biochar reduces efficiency of nitrification inhibitor 3,4-dymethylpyrazole phospate (DMPP) mitigating N2O emissions.

NASA Astrophysics Data System (ADS)

Fuertes-Mendizábal, Teresa; Huérfano, Ximena; Menéndez, Sergio; González-Murua, Carmen; Begoña González-Moro, Mª; Ippolito, James; Kamann, Claudia; Wrage-Mönnig, Nicole; Borchard, Nils; Cayuela, Maria Luz; Spokas, Kurt; Sigua, Gilbert; Novak, Jeff; Estavillo, José Mª

2017-04-01

Nitrous oxide (N2O) is the strongest greenhouse gas associated with agricultural soils. Current agricultural practices, based on the use of N fertilizers, can lead to environmental N losses, with some losses occurring as N2O emissions. Among the strategies suggested by the Intergovernmental Panel on Climate Change to decrease N losses through agriculture is the utilization of nitrification inhibitors, such as DMPP (3,4-dimethylpyrazole phosphate). This compound inhibits nitrification, thus reducing N2O emissions. However, the efficiency of DMPP might be affected by soil amendments. One soil amendment is biochar, which typically increases soil C, can reduce N2O emissions, affect the retention of water, and alter the C and N cycle. Nevertheless, these effects are not uniformly observed across varying soil types, N fertilization schemes and biochar properties. Assuming that both DMPP and biochars with C/N > 30 ratios are presumably able to reduce soil N2O emissions, the aim of this study was to evaluate the synergic effect of a woody biochar applied in combination with DMPP on N2O emissions. For this purpose, a laboratory incubation study was conducted with a silt loam grassland soil and a biochar obtained from Pinus taeda at 500°C. The experimental design consisted of an arrangement including two biochar levels (0 and 2% (w/w)), three fertilization levels (unfertilized, fertilized and fertilized+DMPP) and two soil water content levels (40% and 80% of water filled pore space, WFPS), giving rise to 12 different individual treatments with four replications of each treatment. Soil N2O emissions were monitored over the incubation period (163 days). Results showed that DMPP reduced N2O emissions to levels comparable to the unfertilized controls. Biochar showed ability to mitigate N2O emissions only at the low soil water content (40% WFPS). However, when DMPP was applied to the biochar amended soil, a counteracting effect was observed, since the reduction in N2O emissions induced by DMPP was less than without biochar. This study demonstrates that the biochar amendment diminishes the efficiency of the nitrification inhibitor DMPP both at low and high soil water contents. Aknowledgements: FACCE-CSA n° 276610/MIT04-DESIGN-UPVASC; AGL2015-64582-C3-2-R MINECO/FEDER; IT-932-16.

LOW EMISSION AND HIGH EFFICIENCY RESIDENTIAL PELLET-FIRED HEATERS

EPA Science Inventory

The paper gives results of air emissions testing and efficiency testing on new commercially available under-feed and top-feed residential heaters burning hardwood- and softwood-based pellets. The results were compared with data from earlier models. Reductions in air emissions w...

Interactions between energy efficiency and emission trading under the 1990 Clean Air Act Amendments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hillsman, E.L.; Alvic, D.R.

1994-08-01

The 1990 Clean Air Act Amendments affect electric utilities in numerous ways. The feature that probably has received the greatest attention is the provision to let utilities trade emissions of sulfur dioxide (SO{sub 2}), while at the same time requiring them to reduce S0{sub 2} emissions in 2000 by an aggregate 43%. The emission trading system was welcomed by many as a way of reducing the cost of reducing emissions, by providing greater flexibility than past approaches. This report examines some of the potential interactions between trading emissions and increasing end-use energy efficiency. The analysis focuses on emission trading inmore » the second phase of the trading program, which begins in 2000. The aggregate effects, calculated by an emission compliance and trading model, turn out to be rather small. Aggressive improvement of end-use efficiency by all utilities might reduce allowance prices by $22/ton (1990 dollars), which is small compared to the reduction that has occurred in the estimates of future allowance prices and when compared to the roughly $400/ton price we estimate as a base case. However, the changes in the allowance market that result are large enough to affect some compliance decisions. If utilities in only a few states improve end-use efficiency aggressively, their actions may not have a large effect on the price of an allowance, but they could alter the demand for allowances and thereby the compliance decisions of utilities in other states. The analysis shows how improving electricity end-use efficiency in some states can cause smaller emission reductions in other states, relative to what would have happened without the improvements. Such a result, while not surprising given the theory behind the emission trading system, is upsetting to people who view emissions, environmental protection, and energy efficiency in moral rather than strictly economic terms.« less

Broadband UV spectroscopy system used for monitoring of SO 2 and NO emissions from thermal power plants

NASA Astrophysics Data System (ADS)

Zhang, Y. G.; Wang, H. S.; Somesfalean, G.; Wang, Z. Y.; Lou, X. T.; Wu, S. H.; Zhang, Z. G.; Qin, Y. K.

2010-11-01

A gas monitoring system based on broadband absorption spectroscopic techniques in the ultraviolet region is described and tested. The system was employed in real-time continuous concentration measurements of sulfur dioxide (SO 2) and nitric oxide (NO) from a 220-ton h -1 circulating fluidized bed (CFB) boiler in Shandong province, China. The emission coefficients (per kg of coal and per kWh of electricity) and the total emission of the two pollutant gases were evaluated. The measurement results showed that the emission concentrations of SO 2 and NO from the CFB boiler fluctuated in the range of 750-1300 mg m -3 and 100-220 mg m -3, respectively. Compared with the specified emission standards of air pollutants from thermal power plants in China, the values were generally higher for SO 2 and lower for NO. The relatively high emission concentrations of SO 2 were found to mainly depend on the sulfur content of the fuel and the poor desulfurization efficiency. This study indicates that the broadband UV spectroscopy system is suitable for industrial emission monitoring and pollution control.

Tripartite equilibrium strategy for a carbon tax setting problem in air passenger transport.

PubMed

Xu, Jiuping; Qiu, Rui; Tao, Zhimiao; Xie, Heping

2018-03-01

Carbon emissions in air passenger transport have become increasing serious with the rapidly development of aviation industry. Combined with a tripartite equilibrium strategy, this paper proposes a multi-level multi-objective model for an air passenger transport carbon tax setting problem (CTSP) among an international organization, an airline and passengers with the fuzzy uncertainty. The proposed model is simplified to an equivalent crisp model by a weighted sum procedure and a Karush-Kuhn-Tucker (KKT) transformation method. To solve the equivalent crisp model, a fuzzy logic controlled genetic algorithm with entropy-Bolitzmann selection (FLC-GA with EBS) is designed as an integrated solution method. Then, a numerical example is provided to demonstrate the practicality and efficiency of the optimization method. Results show that the cap tax mechanism is an important part of air passenger trans'port carbon emission mitigation and thus, it should be effectively applied to air passenger transport. These results also indicate that the proposed method can provide efficient ways of mitigating carbon emissions for air passenger transport, and therefore assist decision makers in formulating relevant strategies under multiple scenarios.

Decontamination Efficiency of a DBD Lamp Containing an UV-C Emitting Phosphor.

PubMed

Caillier, Bruno; Caiut, José Maurício Almeida; Muja, Cristina; Demoucron, Julien; Mauricot, Robert; Dexpert-Ghys, Jeanette; Guillot, Philippe

2015-01-01

Among different physical and chemical agents, the UV radiation appears to be an important route for inactivation of resistant microorganisms. The present study introduces a new mercury-free Dielectric Barrier Discharge (DBD) flat lamp, where the biocide action comes from the UV emission produced by rare-earth phosphor obtained by spray pyrolysis, following plasma excitation. In this study, the emission intensity of the prototype lamp is tuned by controlling gas pressure and electrical power, 500 mbar and 15 W, corresponding to optimal conditions. In order to characterize the prototype lamp, the energetic output, temperature increase following lamp ignition and ozone production of the source were measured. The bactericidal experiments carried out showed excellent results for several gram-positive and gram-negative bacterial strains, thus demonstrating the high decontamination efficiency of the DBD flat lamp. Finally, the study of the external morphology of the microorganisms after the exposure to the UV emission suggested that other mechanisms than the bacterial DNA damage could be involved in the inactivation process. © 2015 The American Society of Photobiology.

Assessing Regional Emissions Reductions from Travel Efficiency: Applying the Travel Efficiency Assessment Method

EPA Pesticide Factsheets

This presentation from the 2016 TRB Summer Conference on Transportation Planning and Air Quality summarizes the application of the Travel Efficiency Assessment Method (TEAM) which analyzed selected transportation emission reduction strategies in three case

An aluminium nitride light-emitting diode with a wavelength of 210 nanometres.

PubMed

Taniyasu, Yoshitaka; Kasu, Makoto; Makimoto, Toshiki

2006-05-18

Compact high-efficiency ultraviolet solid-state light sources--such as light-emitting diodes (LEDs) and laser diodes--are of considerable technological interest as alternatives to large, toxic, low-efficiency gas lasers and mercury lamps. Microelectronic fabrication technologies and the environmental sciences both require light sources with shorter emission wavelengths: the former for improved resolution in photolithography and the latter for sensors that can detect minute hazardous particles. In addition, ultraviolet solid-state light sources are also attracting attention for potential applications in high-density optical data storage, biomedical research, water and air purification, and sterilization. Wide-bandgap materials, such as diamond and III-V nitride semiconductors (GaN, AlGaN and AlN; refs 3-10), are potential materials for ultraviolet LEDs and laser diodes, but suffer from difficulties in controlling electrical conduction. Here we report the successful control of both n-type and p-type doping in aluminium nitride (AlN), which has a very wide direct bandgap of 6 eV. This doping strategy allows us to develop an AlN PIN (p-type/intrinsic/n-type) homojunction LED with an emission wavelength of 210 nm, which is the shortest reported to date for any kind of LED. The emission is attributed to an exciton transition, and represents an important step towards achieving exciton-related light-emitting devices as well as replacing gas light sources with solid-state light sources.

New controls spark boiler efficiency

DOE Office of Scientific and Technical Information (OSTI.GOV)

Engels, T.

1993-09-01

Monsanto's NutraSweet plant in University Park, IL, produces aspartame, the patented NutraSweet artificial sweetener product. Until recently, boiler control was managed by a '60s-era Fireye jackshaft system in which air and natural gas were mechanically linked with an offset to compensate for oxygen trim. The interlocking devices on the Fireye system were becoming obsolete, and the boiler needed a new front end retrofitted for low emissions. In order to improve boiler control efficiency, we decided to modernize and automate the entire boiler control system. We replaced the original jackshaft system, and installed a Gordon-Piet burner system, including gas valves, airmore » dampers, blowers, and burner. The upgrade challenges included developing a control strategy and selecting and implementing a process control system. Since our plant has standardized on the PROVOX process management information system from Fisher Controls (now Fisher-Rosemount Systems) to support most of our process, it was a natural and logical choice for boiler controls as well. 2 figs.« less

Method for the control of NOx emissions in long-range space travel.

PubMed

Xu, X H; Shi, Y; Liu, S H; Wang, H P; Chang, S G; Fisher, J W; Pisharody, S; Moran, M; Wignarajah, K

2003-01-01

The wheat straw, an inedible biomass that can be continuously produced in a space vehicle has been used to produce activated carbon for effective control of NOx emissions from the incineration of wastes. The optimal carbonization temperature of wheat straw was found to be around 600 degrees C when a burnoff of 67% was observed. The BET surface area of the activated carbon produced from the wheat straw reached as high as 300 m2/g. The presence of oxygen in flue gas is essential for effective adsorption of NO by activated carbon. On the contrary, water vapor inhibits the adsorption efficiency of NO. Consequently, water vapor in flue gas should be removed by drying agents before adsorption to ensure high NO adsorption efficiency. All of the NO in the flue gas was removed for more than 2 h by the activated carbons when 10% oxygen was present and the ratio of carbon weight to the flue gas flow rate (W/F) was 30 g min/L, with a contact time of 10.2 s. All of NO was reduced to N2 by the activated carbon at 450 degrees C with a W/F ratio of 15 g min/L and a contact time of 5.1 s. Reduction of the adsorbed NO also regenerated the activated carbon, and the regenerated activated carbon exhibited an improved NO adsorption efficiency. However, the reduction of the adsorbed NO resulted in a loss of carbon which was determined to be about 0.99% of the activated carbon per cycle of regeneration. The sufficiency of the amount of wheat straw in providing the activated carbon based on a six-person crew, such as the mission planned for Mars, has been determined. This novel approach for the control of NOx emissions is sustainable in a closed system such as the case in space travel. It is simple to operate and is functional under microgravity environment.

Method for the control of NOx emissions in long-range space travel

NASA Technical Reports Server (NTRS)

Xu, X. H.; Shi, Y.; Liu, S. H.; Wang, H. P.; Chang, S. G.; Fisher, J. W.; Pisharody, S.; Moran, M.; Wignarajah, K.

2003-01-01

The wheat straw, an inedible biomass that can be continuously produced in a space vehicle has been used to produce activated carbon for effective control of NOx emissions from the incineration of wastes. The optimal carbonization temperature of wheat straw was found to be around 600 degrees C when a burnoff of 67% was observed. The BET surface area of the activated carbon produced from the wheat straw reached as high as 300 m2/g. The presence of oxygen in flue gas is essential for effective adsorption of NO by activated carbon. On the contrary, water vapor inhibits the adsorption efficiency of NO. Consequently, water vapor in flue gas should be removed by drying agents before adsorption to ensure high NO adsorption efficiency. All of the NO in the flue gas was removed for more than 2 h by the activated carbons when 10% oxygen was present and the ratio of carbon weight to the flue gas flow rate (W/F) was 30 g min/L, with a contact time of 10.2 s. All of NO was reduced to N2 by the activated carbon at 450 degrees C with a W/F ratio of 15 g min/L and a contact time of 5.1 s. Reduction of the adsorbed NO also regenerated the activated carbon, and the regenerated activated carbon exhibited an improved NO adsorption efficiency. However, the reduction of the adsorbed NO resulted in a loss of carbon which was determined to be about 0.99% of the activated carbon per cycle of regeneration. The sufficiency of the amount of wheat straw in providing the activated carbon based on a six-person crew, such as the mission planned for Mars, has been determined. This novel approach for the control of NOx emissions is sustainable in a closed system such as the case in space travel. It is simple to operate and is functional under microgravity environment.

Solid state SPS microwave generation and transmission study. Volume 2, phase 2: Appendices

NASA Technical Reports Server (NTRS)

Maynard, O. E.

1980-01-01

The solid state sandwich concept for SPS was further defined. The design effort concentrated on the spacetenna, but did include some system analysis for parametric comparison reasons. Basic solid state microwave devices were defined and modeled. An initial conceptual subsystems and system design was performed as well as sidelobe control and system selection. The selected system concept and parametric solid state microwave power transmission system data were assessed relevant to the SPS concept. Although device efficiency was not a goal, the sensitivities to design of this efficiency were parametrically treated. Sidelobe control consisted of various single step tapers, multistep tapers and Gaussian tapers. A hybrid concept using tubes and solid state was evaluated. Thermal analyses are included with emphasis on sensitivities to waste heat radiator form factor, emissivity, absorptivity, amplifier efficiency, material and junction temperature.

Experiential study on temperature and emission performance of micro burner during porous media combustion

NASA Astrophysics Data System (ADS)

Janvekar, Ayub Ahmed; Abdullah, M. Z.; Ahmad, Z. A.; Abas, A.; Ismail, A. K.; Hussien, A. A.; Kataraki, P. S.; Ishak, M. H. H.; Mazlan, M.; Zubair, A. F.

2018-05-01

Addition of porous materials in reaction zone give rise to significant improvements in combustion performance. In this work, a dual layered micro porous media burner was tested for stable flame and emissions. Reaction and preheat layer was made up of discrete (zirconia) and foam (porcelain) type of materials respectively. Three different thickness of reaction zone was tested, each with 10, 20 and 30mm. Interestingly, only 20mm thick layer can able to show better thermal efficiency of 72% as compared to 10 and 30mm. Best equivalence ratio came out to be 0.7 for surface and 0.6 for submerged flame conditions. Moreover, emission was continuously monitored to detect presence of NOx and CO, which were under controlled limits.

Natural gas anodes for aluminium electrolysis in molten fluorides.

PubMed

Haarberg, Geir Martin; Khalaghi, Babak; Mokkelbost, Tommy

2016-08-15

Industrial primary production of aluminium has been developed and improved over more than 100 years. The molten salt electrolysis process is still suffering from low energy efficiency and considerable emissions of greenhouse gases (CO2 and PFC). A new concept has been suggested where methane is supplied through the anode so that the CO2 emissions may be reduced significantly, the PFC emissions may be eliminated and the energy consumption may decrease significantly. Porous carbon anodes made from different graphite grades were studied in controlled laboratory experiments. The anode potential, the anode carbon consumption and the level of HF gas above the electrolyte were measured during electrolysis. In some cases it was found that the methane oxidation was effectively participating in the anode process.

Non-agricultural ammonia emissions in urban China

NASA Astrophysics Data System (ADS)

Chang, Y. H.

2014-03-01

The non-agricultural ammonia (NH3) emissions in cities have received little attention but could rival agricultural sources in term of the efficiency in PM formation. The starting point for finding credible solutions is to comprehensively establish a city-specific Non-agricultural Ammonia Emission Inventory (NAEI) and identify the largest sources where efforts can be directed to deliver the largest impact. In this paper, I present a NAEI of 113 national key cities targeted on environmental protection in China in 2010, which for the first time covers NH3 emissions from pets, infants, smokers, green land, and household products. Results show that totally 210 478 Mg, the NH3 emissions from traffic, fuel combustion, waste disposal, pets, green land, human, and household products are 67 671 Mg, 56 275 Mg, 44 289 Mg, 23 355 Mg, 7509 Mg, 7312 Mg, and 4069 Mg, respectively. The NH3 emission intensity from the municipal districts ranges from 0.08 to 3.13 Mg km-2 yr-1, with a average of 0.84 Mg km-2 yr-1. The high NH3 emission intensities in Beijing-Tianjin-Hebei region, Yangtze River Delta region and Pearl River Delta region support the view that non-agricultural NH3 sources play a key role in city-scale NH3 emissions and thus have potentially important implications for secondary PM formation (ammonium-sulfate-nitrate system) in urban agglomeration of China. Therefore, in addition to current SO2 and NOx controls, China also needs to allocate more scientific, technical, and legal resources on controlling non-agricultural NH3 emissions in the future.

Refueling emissions from cars in Japan: Compositions, temperature dependence and effect of vapor liquefied collection system

NASA Astrophysics Data System (ADS)

Yamada, Hiroyuki; Inomata, Satoshi; Tanimoto, Hiroshi

2015-11-01

Refueling emissions from cars available on the Japanese market, which were not equipped with specific controlling devices, were investigated. For the composition analysis, a proton transfer reaction plus switchable reagent ion mass spectrometry (PTR + SRI-MS), which is capable of real-time measurement, was used. In addition, the performance of a vapor liquefied collection system (VLCS), which is a recently developed controlling device, was evaluated and compared with an onboard refueling vapor recovery (ORVR) system. The refueling emission factor of uncontrolled vehicles at 20 °C was 1.02 ± 0.40 g/L in the case dispensing 20 L of fuel. The results of composition analysis indicated that the maximum incremental reactivity (MIR) of refueling emissions in Japan was 3.49 ± 0.83. The emissions consist of 80% alkanes and 20% alkenes, and aromatics and di-enes were negligible. C4 alkene had the highest impact on the MIR of refueling emissions. The amounts of refueling emissions were well reproduced by a function developed by MOVE2010 in the temperature range of 5-35 °C. The compositions of the refueling emissions varied in this temperature range, but the change in MIR was negligible. The trapping efficiency of VLCS was the same level as that of the ORVR (over 95%). The MIRs of refueling and evaporative emissions were strongly affected by that of the test fuel. This study and our previous study indicated that MIRbreakthrough ≈ MIRrefueling ≈ MIRfuel + 0.5 and MIRpermeation ≈ MIRfuel. The real-world estimated average MIRfuel in Japan was about 3.0.

The roles of energy and material efficiency in meeting steel industry CO2 targets.

PubMed

Milford, Rachel L; Pauliuk, Stefan; Allwood, Julian M; Müller, Daniel B

2013-04-02

Identifying strategies for reducing greenhouse gas emissions from steel production requires a comprehensive model of the sector but previous work has either failed to consider the whole supply chain or considered only a subset of possible abatement options. In this work, a global mass flow analysis is combined with process emissions intensities to allow forecasts of future steel sector emissions under all abatement options. Scenario analysis shows that global capacity for primary steel production is already near to a peak and that if sectoral emissions are to be reduced by 50% by 2050, the last required blast furnace will be built by 2020. Emissions reduction targets cannot be met by energy and emissions efficiency alone, but deploying material efficiency provides sufficient extra abatement potential.

Automotive Stirling engine system component review

NASA Technical Reports Server (NTRS)

Hindes, Chip; Stotts, Robert

1987-01-01

The design and testing of the power and combustion control system for the basic Stirling engine, Mod II, are examined. The power control system is concerned with transparent operation, and the Mod II uses engine working gas pressure variation to control the power output of the engine. The main components of the power control system, the power control valve, the pump-down system, and the hydrogen stable system, are described. The combustion control system consists of a combustion air supply system and an air/fuel ratio control system, and the system is to maintain constant heater head temperature, and to maximize combustion efficiency and to minimize exhaust emissions.

Win–Win strategies to promote air pollutant control policies and non-fossil energy target regulation in China

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Lining; Patel, Pralit L.; Yu, Sha

The rapid growth of energy consumption in China has led to increased emissions of air pollutants. As a response, in its 12th Five Year Plan the Chinese government proposed mitigation targets for SO2 and NOx emissions. Herein we have investigated mitigation measures taken in different sectors and their corresponding impacts on the energy system. Additionally, as non-fossil energy development has gained traction in addressing energy and environmental challenges in China, we further investigated the impact of non-fossil energy development on air pollutant emissions, and then explored interactions and co-benefits between these two types of policies. An extended Global Change Assessmentmore » Model (GCAM) was used in this study, which includes an additional air pollutant emissions control module coupling multiple end-of-pipe (EOP) control technologies with energy technologies, as well as more detailed end-use sectors in China. We find that implementing EOP control technologies would reduce air pollution in the near future, but with little room left to implement these EOP technologies, other cleaner and more efficient technologies are also effective. These technologies would reduce final energy consumption, increase electricity’s share in final energy, and increase the share of non-fossil fuels in primary energy and electricity consumption. Increasing non-fossil energy usage at China’s proposed adoption rate would in turn also reduce SO2 and NOx emissions, however, the reductions from this policy alone still lag behind the targeted requirements of air pollutant reduction. Fortunately, a combination of air pollutant controls and non-fossil energy development could synergistically help realize the respective individual targets, and would result in lower costs than would addressing these issues separately.« less

Energy Efficient Community Development in California: Chula Vista Research Project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gas Technology Institute

2009-03-31

In 2007, the U.S. Department of Energy joined the California Energy Commission in funding a project to begin to examine the technical, economic and institutional (policy and regulatory) aspects of energy-efficient community development. That research project was known as the Chula Vista Research Project for the host California community that co-sponsored the initiative. The researches proved that the strategic integration of the selected and economically viable buildings energy efficiency (EE) measures, photovoltaics (PV), distributed generation (DG), and district cooling can produce significant reductions in aggregate energy consumption, peak demand and emissions, compared to the developer/builder's proposed baseline approach. However, themore » central power plant emission reductions achieved through use of the EE-DG option would increase local air emissions. The electric and natural gas utility infrastructure impacts associated with the use of the EE and EE-PV options were deemed relatively insignificant while use of the EE-DG option would result in a significant reduction of necessary electric distribution facilities to serve a large-scale development project. The results of the Chula Vista project are detailed in three separate documents: (1) Energy-Efficient Community Development in California; Chula Vista Research Project report contains a detailed description of the research effort and findings. This includes the methodologies, and tools used and the analysis of the efficiency, economic and emissions impacts of alternative energy technology and community design options for two development sites. Research topics covered included: (a) Energy supply, demand, and control technologies and related strategies for structures; (b) Application of locally available renewable energy resources including solar thermal and PV technology and on-site power generation with heat recovery; (c) Integration of local energy resources into district energy systems and existing energy utility networks; (d) Alternative land-use design and development options and their impact on energy efficiency and urban runoff, emissions and the heat island effect; and (e) Alternative transportation and mobility options and their impact on local emissions. (2) Creating Energy-Efficient Communities in California: A Reference Guide to Barriers, Solutions and Resources report provides the results of an effort to identify the most innovative existing and emerging public policy, incentive and market mechanisms that encourage investment in advanced energy technologies and enabling community design options in the State of California and the nation. The report evaluates each of these mechanisms in light of the preceding research and concludes with a set of recommended mechanisms designed for consideration by relevant California State agencies, development and finance industry associations, and municipal governments. (3) Creating Energy-Efficient Communities in California: A Technical Reference Guide to Building and Site Design report contains a set of selected commercially viable energy technology and community design options for high-efficiency, low-impact community development in California. It includes a summary of the research findings referenced above and recommendations for energy technology applications and energy-efficient development strategies for residential, commercial and institutional structures and supporting municipal infrastructure for planned communities. The document also identifies design options, technology applications and development strategies that are applicable to urban infill projects.« less

Biofilter application for control of BTEX compounds from glycol dehydrator condenser vent gases at oil and natural gas producing facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stewart, W.C.; Kamarthi, R.S.

1997-12-31

Compliance with 1990 Clean Air Act Amendments will require cost-effective control technologies to reduce air emissions for petroleum industries. EPA has also proposed a new MACT Rule for Oil and Natural Gas Producing Facilities which will require control of emissions from glycol dehydrator vents. Control of volatile organic compound (VOC) emissions such as benzene, toluene, ethylbenzene, and xylene (BTEX) is one of the major concerns for the petroleum industries. Traditional VOC control methods may not be economically feasible to meet the requirements of these regulations. Recent studies have shown that biofilters can cost-effectively remove BTEX compounds with greater than 95%more » efficiency. This paper describes results from field testing a biofilter at an Oil and Natural Gas Producing facility. The biofilter treats a low flow gas stream containing high concentrations of VOCs and carbon dioxide from a glycol dehydrator condenser vent. A modular high-rate vapor phase biofilter developed by BioiReaction Industries was used to investigate the feasibility of this low-cost technology. Due to the high VOC loading (BTEX compounds up to 18,000 ppm; total VOCs 50,000 to 90,000 ppm), three modular biofilters were installed in series.« less

Current status and prediction of major atmospheric emissions from coal-fired power plants in Shandong Province, China

NASA Astrophysics Data System (ADS)

Xiong, Tianqi; Jiang, Wei; Gao, Weidong

2016-01-01

Shandong is considered to be the top provincial emitter of air pollutants in China due to its large consumption of coal in the power sector and its dense distribution of coal-fired plants. To explore the atmospheric emissions of the coal-fired power sector in Shandong, an updated emission inventory of coal-fired power plants for the year 2012 in Shandong was developed. The inventory is based on the following parameters: coal quality, unit capacity and unit starting year, plant location, boiler type and control technologies. The total SO2, NOx, fine particulate matter (PM2.5) and mercury (Hg) emissions are estimated at 705.93 kt, 754.30 kt, 63.99 kt and 10.19 kt, respectively. Larger units have cleaner emissions than smaller ones. The coal-fired units (≥300 MW) are estimated to account for 35.87% of SO2, 43.24% of NOx, 47.74% of PM2.5 and 49.83% of Hg emissions, which is attributed primarily to the improved penetration of desulfurization, LNBs, denitration and dust-removing devices in larger units. The major regional contributors are southwestern cities, such as Jining, Liaocheng, Zibo and Linyi, and eastern cities, such as Yantai and Qindao. Under the high-efficiency control technology (HECT) scenario analysis, emission reductions of approximately 58.61% SO2, 80.63% NOx, 34.20% PM2.5 and 50.08% Hg could be achieved by 2030 compared with a 2012 baseline. This inventory demonstrates why it is important for policymakers and researchers to assess control measure effectiveness and to supply necessary input for regional policymaking and the management of the coal-fired power sector in Shandong.

Highly efficient and stable white organic light emitting diode base on double recombination zones of phosphorescent blue/orange emitters.

PubMed

Lee, Seok Jae; Koo, Ja Ryong; Lim, Dong Hwan; Park, Hye Rim; Kim, Young Kwan; Ha, Yunkyoung

2011-08-01

We demonstrated efficient and stable white phosphorescent organic light-emitting diodes (OLEDs) with double-emitting layers (D-EMLs), which were comprised of two emissive layers with a hole transport-type host of N,N'-dicarbazolyl-3,5-benzene (mCP) and a electron transport-type host of 2,2',2"-(1,3,5-benzenetryl)tris(1-phenyl)-1H-benzimidazol (TPBi) with blue/orange emitters, respectively. We fabricated two type white devices with single emitting layer (S-EML) and D-EML of orange emitter, maintaining double recombination zone of blue emitter. In addition, the device architecture was developed to confine excitons inside the D-EMLs and to manage triplet excitons by controlling the charge injection. As a result, light-emitting performances of white OLED with D-EMLs were improved and showed the steady CIE coordinates compared to that with S-EML of orange emitter, which demonstrated the maximum luminous efficiency and external quantum efficiency were 21.38 cd/A and 11.09%. It also showed the stable white emission with CIE(x,y) coordinates from (x = 0.36, y = 0.37) at 6 V to (x = 0.33, y = 0.38) at 12 V.

Control of harmful hydrocarbon species in the exhaust of modern advanced GDI engines

NASA Astrophysics Data System (ADS)

Hasan, A. O.; Abu-jrai, A.; Turner, D.; Tsolakis, A.; Xu, H. M.; Golunski, S. E.; Herreros, J. M.

2016-03-01

A qualitative and quantitative analysis of toxic but currently non-regulated hydrocarbon compounds ranging from C5-C11, before and after a zoned three-way catalytic converter (TWC) in a modern gasoline direct injection (GDI) engine has been studied using gas chromatography-mass spectrometry (GC-MS). The GDI engine has been operated under conventional and advanced combustion modes, which result in better fuel economy and reduced levels of NOx with respect to standard SI operation. However, these fuel-efficient conditions are more challenging for the operation of a conventional TWC, and could lead to higher level of emissions released to the environment. Lean combustion leads to the reduction in pumping losses, fuel consumption and in-cylinder emission formation rates. However, lean HCCI will lead to high levels of unburnt HCs while the presence of oxygen will lower the TWC efficiency for NOx control. The effect on the catalytic conversion of the hydrocarbon species of the addition of hydrogen upstream the catalyst has been also investigated. The highest hydrocarbon engine-out emissions were produced for HCCI engine operation at low engine load operation. The catalyst was able to remove most of the hydrocarbon species to low levels (below the permissible exposure limits) for standard and most of the advanced combustion modes, except for naphthalene (classified as possibly carcinogenic to humans by the International Agency for Research on Cancer) and methyl-naphthalene (which has the potential to cause lung damage). However, when hydrogen was added upstream of the catalyst, the catalyst conversion efficiency in reducing methyl-naphthalene and naphthalene was increased by approximately 21%. This results in simultaneous fuel economy and environmental benefits from the effective combination of advanced combustion and novel aftertreatment systems.

Hydrogen Fueled Hybrid Solid Oxide Fuel Cell-Gas Turbine (SOFC-GT) System for Long-Haul Rail Application

NASA Astrophysics Data System (ADS)

Chow, Justin Jeff

Freight movement of goods is the artery for America's economic health. Long-haul rail is the premier mode of transport on a ton-mile basis. Concerns regarding greenhouse gas and criteria pollutant emissions, however, have motivated the creation of annually increasing locomotive emissions standards. Health issues from diesel particulate matter, especially near rail yards, have also been on the rise. These factors and the potential to raise conventional diesel-electric locomotive performance warrants the investigation of using future fuels in a more efficient system for locomotive application. This research evaluates the dynamic performance of a Solid Oxide Fuel Cell-Gas Turbine (SOFC-GT) Hybrid system operating on hydrogen fuel to power a locomotive over a rail path starting from the Port of Los Angeles and ending in the City of Barstow. Physical constraints, representative locomotive operation logic, and basic design are used from a previous feasibility study and simulations are performed in the MATLAB Simulink environment. In-house controls are adapted to and expanded upon. Results indicate high fuel-to-electricity efficiencies of at least 54% compared to a conventional diesel-electric locomotive efficiency of 35%. Incorporation of properly calibrated feedback and feed-forward controls enables substantial load following of difficult transients that result from train kinematics while maintaining turbomachinery operating requirements and suppressing thermal stresses in the fuel cell stack. The power split between the SOFC and gas turbine is deduced to be a deterministic factor in the balance between capital and operational costs. Using hydrogen results in no emissions if renewable and offers a potential of 24.2% fuel energy savings for the rail industry.

Comparative Study of Different Methods for Soot Sensing and Filter Monitoring in Diesel Exhausts.

PubMed

Feulner, Markus; Hagen, Gunter; Hottner, Kathrin; Redel, Sabrina; Müller, Andreas; Moos, Ralf

2017-02-18

Due to increasingly tighter emission limits for diesel and gasoline engines, especially concerning particulate matter emissions, particulate filters are becoming indispensable devices for exhaust gas after treatment. Thereby, for an efficient engine and filter control strategy and a cost-efficient filter design, reliable technologies to determine the soot load of the filters and to measure particulate matter concentrations in the exhaust gas during vehicle operation are highly needed. In this study, different approaches for soot sensing are compared. Measurements were conducted on a dynamometer diesel engine test bench with a diesel particulate filter (DPF). The DPF was monitored by a relatively new microwave-based approach. Simultaneously, a resistive type soot sensor and a Pegasor soot sensing device as a reference system measured the soot concentration exhaust upstream of the DPF. By changing engine parameters, different engine out soot emission rates were set. It was found that the microwave-based signal may not only indicate directly the filter loading, but by a time derivative, the engine out soot emission rate can be deduced. Furthermore, by integrating the measured particulate mass in the exhaust, the soot load of the filter can be determined. In summary, all systems coincide well within certain boundaries and the filter itself can act as a soot sensor.

Comparative Study of Different Methods for Soot Sensing and Filter Monitoring in Diesel Exhausts

PubMed Central

Feulner, Markus; Hagen, Gunter; Hottner, Kathrin; Redel, Sabrina; Müller, Andreas; Moos, Ralf

2017-01-01

Due to increasingly tighter emission limits for diesel and gasoline engines, especially concerning particulate matter emissions, particulate filters are becoming indispensable devices for exhaust gas after treatment. Thereby, for an efficient engine and filter control strategy and a cost-efficient filter design, reliable technologies to determine the soot load of the filters and to measure particulate matter concentrations in the exhaust gas during vehicle operation are highly needed. In this study, different approaches for soot sensing are compared. Measurements were conducted on a dynamometer diesel engine test bench with a diesel particulate filter (DPF). The DPF was monitored by a relatively new microwave-based approach. Simultaneously, a resistive type soot sensor and a Pegasor soot sensing device as a reference system measured the soot concentration exhaust upstream of the DPF. By changing engine parameters, different engine out soot emission rates were set. It was found that the microwave-based signal may not only indicate directly the filter loading, but by a time derivative, the engine out soot emission rate can be deduced. Furthermore, by integrating the measured particulate mass in the exhaust, the soot load of the filter can be determined. In summary, all systems coincide well within certain boundaries and the filter itself can act as a soot sensor. PMID:28218700

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ashford, Mike

The report describes the prospects for energy efficiency and greenhouse gas emissions reductions in Mexico, along with renewable energy potential. A methodology for developing emissions baselines is shown, in order to prepare project emissions reductions calculations. An application to the USIJI program was also prepared through this project, for a portfolio of energy efficiency projects.

Performance analysis of CO(2) emissions and energy efficiency of metal industries in China.

PubMed

Shao, Chaofeng; Guan, Yang; Wan, Zheng; Chu, Chunli; Ju, Meiting

2014-02-15

Nonferrous metal industries play an important role in China's national economy and are some of the country's largest energy consumers. To better understand the nature of CO(2) emissions from these industries and to further move towards low-carbon development in this industry sector, this study investigates the CO(2) emissions of 12 nonferrous metal industries from 2003 to 2010 based on their life-cycle assessments. It then classifies these industries into four "emission-efficiency" types through cluster analysis. The results show that (1) the industrial economy and energy consumption of China's nonferrous metal industries have grown rapidly, although their recent energy consumption rate shows a declining trend. (2) The copper, aluminum, zinc, lead, and magnesium industries, classified as high-emission industries, are the main contributors of CO(2) emissions. The results have implications for policy decisions that aim to enhance energy efficiency, particularly for promoting the transformation of low-efficiency industries to high-efficiency ones. The study also highlights the important role of policy development in technological innovations, optimization, and upgrades, the reduction of coal proportion in energy consumption, and the advancement of new energy sources. Copyright © 2014 Elsevier Ltd. All rights reserved.

Models to predict emissions of health-damaging pollutants and global warming contributions of residential fuel/stove combinations in China.

PubMed

Edwards, Rufus D; Smith, Kirk R; Zhang, Junfeng; Ma, Yuqing

2003-01-01

Residential energy use in developing countries has traditionally been associated with combustion devices of poor energy efficiency, which have been shown to produce substantial health-damaging pollution, contributing significantly to the global burden of disease, and greenhouse gas (GHG) emissions. Precision of these estimates in China has been hampered by limited data on stove use and fuel consumption in residences. In addition limited information is available on variability of emissions of pollutants from different stove/fuel combinations in typical use, as measurement of emission factors requires measurement of multiple chemical species in complex burn cycle tests. Such measurements are too costly and time consuming for application in conjunction with national surveys. Emissions of most of the major health-damaging pollutants (HDP) and many of the gases that contribute to GHG emissions from cooking stoves are the result of the significant portion of fuel carbon that is diverted to products of incomplete combustion (PIC) as a result of poor combustion efficiencies. The approximately linear increase in emissions of PIC with decreasing combustion efficiencies allows development of linear models to predict emissions of GHG and HDP intrinsically linked to CO2 and PIC production, and ultimately allows the prediction of global warming contributions from residential stove emissions. A comprehensive emissions database of three burn cycles of 23 typical fuel/stove combinations tested in a simulated village house in China has been used to develop models to predict emissions of HDP and global warming commitment (GWC) from cooking stoves in China, that rely on simple survey information on stove and fuel use that may be incorporated into national surveys. Stepwise regression models predicted 66% of the variance in global warming commitment (CO2, CO, CH4, NOx, TNMHC) per 1 MJ delivered energy due to emissions from these stoves if survey information on fuel type was available. Subsequently if stove type is known, stepwise regression models predicted 73% of the variance. Integrated assessment of policies to change stove or fuel type requires that implications for environmental impacts, energy efficiency, global warming and human exposures to HDP emissions can be evaluated. Frequently, this involves measurement of TSP or CO as the major HDPs. Incorporation of this information into models to predict GWC predicted 79% and 78% of the variance respectively. Clearly, however, the complexity of making multiple measurements in conjunction with a national survey would be both expensive and time consuming. Thus, models to predict HDP using simple survey information, and with measurement of either CO/CO2 or TSP/CO2 to predict emission factors for the other HDP have been derived. Stepwise regression models predicted 65% of the variance in emissions of total suspended particulate as grams of carbon (TSPC) per 1 MJ delivered if survey information on fuel and stove type was available and 74% if the CO/CO2 ratio was measured. Similarly stepwise regression models predicted 76% of the variance in COC emissions per MJ delivered with survey information on stove and fuel type and 85% if the TSPC/CO2 ratio was measured. Ultimately, with international agreements on emissions trading frameworks, similar models based on extensive databases of the fate of fuel carbon during combustion from representative household stoves would provide a mechanism for computing greenhouse credits in the residential sector as part of clean development mechanism frameworks and monitoring compliance to control regimes.

Addition agents effects on hydrocarbon fuels burning

NASA Astrophysics Data System (ADS)

Larionov, V. M.; Mitrofanov, G. A.; Sakhovskii, A. V.

2016-01-01

Literature review on addition agents effects on hydrocarbon fuels burning has been conducted. The impact results in flame pattern and burning velocity change, energy efficiency increase, environmentally harmful NOx and CO emission reduction and damping of self-oscillations in flow. An assumption about water molecules dissociation phenomenon existing in a number of practical applications and being neglected in most explanations for physical- chemical processes taking place in case of injection of water/steam into combustion zone has been noted. The hypothesis about necessity of water dissociation account has been proposed. It can be useful for low temperature combustion process control and NOx emission reduction.

Spin injection in n-type resonant tunneling diodes

PubMed Central

2012-01-01

We have studied the polarized resolved photoluminescence of n-type GaAs/AlAs/GaAlAs resonant tunneling diodes under magnetic field parallel to the tunnel current. Under resonant tunneling conditions, we have observed two emission lines attributed to neutral (X) and negatively charged excitons (X−). We have observed a voltage-controlled circular polarization degree from the quantum well emission for both lines, with values up to −88% at 15 T at low voltages which are ascribed to an efficient spin injection from the 2D gases formed at the accumulation layers. PMID:23098559

Phenylene bridged boron-nitrogen containing dendrimers.

PubMed

Proń, Agnieszka; Baumgarten, Martin; Müllen, Klaus

2010-10-01

The synthesis and characterization of novel phenylene bridged boron-nitrogen containing π-conjugated dendrimers N3B6 and N3B3, with peripheral boron atoms and 1,3,5-triaminobenzene moiety as a core, are presented. UV-vis absorption and emission measurements reveal that the optical properties of the resulting compounds can be controlled by changing the donor/acceptor ratio: a 1:1 ratio results in a more efficient charge transfer than the 1:2 ratio. This was proven by the red shift of the emission maxima and the stronger solvatochromic effect in N3B3 compared to N3B6.

In-use catalyst surface area and its relation to HC conversion efficiency and FTP emissions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Donahue, K.S.; Sabourin, M.A.; Larson, R.E.

1986-01-01

Surface area data, steady-state hydrocarbon conversion efficiency data, and hydrocarbon emissions results have been determined for catalysts collected by the U.S. Environmental Protection Agency from properly maintained 1981 and 1982 model year vehicles. Catalysts covered in this study were limited to those with three-way-plus-oxidation monolith technologies. Catalyst surface areas were measured using the BET method, conversion efficiencies were measured on an exhaust gas generator, and emissions results were determined using the Urban Driving Schedule of the Federal Test Procedure. Results indicate that correlation of catalyst surface area data with hydrocarbon conversion efficiency data and hydrocarbon emissions results is significant formore » the sample studied.« less

Highly Efficient Defect Emission from ZnO:Zn and ZnO:S Powders

NASA Astrophysics Data System (ADS)

Everitt, Henry

2013-03-01

Bulk Zinc Oxide (ZnO) is a wide band gap semiconductor with an ultraviolet direct band gap energy of 3.4 eV and a broad, defect-related visible wavelength emission band centered near 2 eV. We have shown that the external quantum efficiency can exceed 50% for this nearly white emission band that closely matches the human dark-adapted visual response. To explore the potential of ZnO as a rare earth-free white light phosphor, we investigated the mechanism of efficient defect emission in three types of ZnO powders: unannealed, annealed, and sulfur-doped. Annealing and sulfur-doping of ZnO greatly increase the strength of defect emission while suppressing the UV band edge emission. Continuous wave and ultrafast one- and two-photon excitation spectroscopy are used to examine the defect emission mechanism. Low temperature photoluminescence (PL) and PL excitation (PLE) spectra were measured for all three compounds, and it was found that bound excitons mediate the defect emission. Temperature-dependent PLE spectra for the defect and band edge emission were measured to estimate trapping and activation energies of the bound excitons and clarify the role they play in the defect emission. Time-resolved techniques were used to ascertain the role of exciton diffusion, the effects of reabsorption, and the spatial distributions of radiative and non-radiative traps. In unannealed ZnO we find that defect emission is suppressed and UV band edge emission is inefficient (< 2%) because of reabsorption and non-radiative recombination due to a high density of non-radiative bulk traps. By annealing ZnO, bulk trap densities are reduced, and a high density of defects responsible for the broad visible emission are created near the surface. Interestingly, nearly identical PLE spectra are found for both the band edge and the defect emission, one of many indications that the defect emission is deeply connected to bound excitons. Quantum efficiency, also measured as a function of excitation wavelength, closely mirrors the PLE spectra for both emission bands. Sulfur-doped ZnO exhibits additional PLE and X-ray features indicative of a ZnS-rich surface shell that correlates with even more efficient defect emission. The results presented here offer hope that engineering defects in ZnO materials may significantly improve the quantum efficiency for white light phosphor applications. This work was supported by the Army's in-house laboratory innovative research program.

Reduction of external noise of mobile energy facilities by using active noise control system in muffler

NASA Astrophysics Data System (ADS)

Polivaev, O. I.; Kuznetsov, A. N.; Larionov, A. N.; Beliansky, R. G.

2018-03-01

The paper describes a method for the reducing emission of low-frequency noise of modern automotive vehicles into the environment. The importance of reducing the external noise of modern mobile energy facilities made in Russia is substantiated. Standard methods for controlling external noise in technology are of low efficiency when low-frequency sound waves are reduced. In this case, it is in the low-frequency zone of the sound range that the main power of the noise emitted by the machinery lies. The most effective way to reduce such sound waves is to use active noise control systems. A design of a muffler using a similar system is presented. This muffler allowed one to reduce the emission of increased noise levels into the environment by 7-11 dB and to increase acoustic comfort at the operator's workplace by 3-5 dB.

Terahertz Focusing and Polarization Control in Large-Area Bias-Free Semiconductor Emitters

NASA Astrophysics Data System (ADS)

Carthy, Joanna L.; Gow, Paul C.; Berry, Sam A.; Mills, Ben; Apostolopoulos, Vasilis

2018-03-01

We show that, when large-area multiplex terahertz semiconductor emitters, that work on diffusion currents and Schottky potentials, are illuminated by ultrashort optical pulses they can radiate a directional electromagnetic terahertz pulse which is controlled by the angular spectrum of the incident optical beam. Using the lens that focuses the incident near-infrared pulse, we have demonstrated THz emission focusing in free space, at the same point where the optical radiation would focus. We investigated the beam waist and Gouy phase shift of the THz emission as a function of frequency. We also show that the polarization profile of the emitted THz can be tailored by the metallic patterning on the semiconductor, demonstrating radial polarization when a circular emitter design is used. Our techniques can be used for fast THz beam steering and mode control for efficiently coupling to waveguides without the need for THz lenses or parabolic mirrors.

Active magneto-optical control of spontaneous emission in graphene

DOE PAGES

Kort-Kamp, W. J. M.; Amorim, B.; Bastos, G.; ...

2015-11-13

In this study, we investigate the spontaneous emission rate of a two-level quantum emitter near a graphene-coated substrate under the influence of an external magnetic field or strain induced pseudomagnetic field. We demonstrate that the application of the magnetic field can substantially increase or decrease the decay rate. We show that a suppression as large as 99% in the Purcell factor is achieved even for moderate magnetic fields. The emitter's lifetime is a discontinuous function of |B|, which is a direct consequence of the occurrence of discrete Landau levels in graphene. We demonstrate that, in the near-field regime, the magneticmore » field enables an unprecedented control of the decay pathways into which the photon/polariton can be emitted. Our findings strongly suggest that a magnetic field could act as an efficient agent for on-demand, active control of light-matter interactions in graphene at the quantum level.« less

Site-Controlled Growth of Monolithic InGaAs/InP Quantum Well Nanopillar Lasers on Silicon.

PubMed

Schuster, Fabian; Kapraun, Jonas; Malheiros-Silveira, Gilliard N; Deshpande, Saniya; Chang-Hasnain, Connie J

2017-04-12

In this Letter, we report the site-controlled growth of InP nanolasers on a silicon substrate with patterned SiO 2 nanomasks by low-temperature metal-organic chemical vapor deposition, compatible with silicon complementary metal-oxide-semiconductor (CMOS) post-processing. A two-step growth procedure is presented to achieve smooth wurtzite faceting of vertical nanopillars. By incorporating InGaAs multiquantum wells, the nanopillar emission can be tuned over a wide spectral range. Enhanced quality factors of the intrinsic InP nanopillar cavities promote lasing at 0.87 and 1.21 μm, located within two important optical telecommunication bands. This is the first demonstration of a site-controlled III-V nanolaser monolithically integrated on silicon with a silicon-transparent emission wavelength, paving the way for energy-efficient on-chip optical links at typical telecommunication wavelengths.

A High Fuel Consumption Efficiency Management Scheme for PHEVs Using an Adaptive Genetic Algorithm

PubMed Central

Lee, Wah Ching; Tsang, Kim Fung; Chi, Hao Ran; Hung, Faan Hei; Wu, Chung Kit; Chui, Kwok Tai; Lau, Wing Hong; Leung, Yat Wah

2015-01-01

A high fuel efficiency management scheme for plug-in hybrid electric vehicles (PHEVs) has been developed. In order to achieve fuel consumption reduction, an adaptive genetic algorithm scheme has been designed to adaptively manage the energy resource usage. The objective function of the genetic algorithm is implemented by designing a fuzzy logic controller which closely monitors and resembles the driving conditions and environment of PHEVs, thus trading off between petrol versus electricity for optimal driving efficiency. Comparison between calculated results and publicized data shows that the achieved efficiency of the fuzzified genetic algorithm is better by 10% than existing schemes. The developed scheme, if fully adopted, would help reduce over 600 tons of CO2 emissions worldwide every day. PMID:25587974

Enhanced NH3 emission from swine liquid waste

NASA Astrophysics Data System (ADS)

Lee, S.; Robarge, W. P.; Walker, J. T.

2010-12-01

Swine animal feeding operations are sources of emissions for various gases [ammonia (NH3), hydrogen sulfide (H2S), carbon dioxide (CO2), volatile organic carbons (VOCs)], and fine particulate matter. Gaseous emissions from simple aqueous systems are typically controlled by temperature, pH, wind speed, total dissolved concentration of the chemical species of interest (e.g. NH3+NH4+ = TAN), and the Henry’s law constant. Ammonia emissions from three different sources [ammonium sulfate (AS), swine anaerobic lagoon liquid (SLL), and pit liquid (SPL) from swine housing units] were evaluated using a small flow-through teflon-lined chamber (SFTC; 0.3m × 0.2m × 0.15m) under controlled laboratory conditions. The SFTC was designed for 100% collection efficiency of NH3 gas emitted from the liquids. The internal volume of the chamber, 9 L, was exchanged 1.1 times per minute. All three liquid formulations exhibit the expected response in emissions with changes in temperature and pH. However, NH3 emissions from the SPL and SLL are ~5 times those from pure solutions of AS. Furthermore, the enhancement in NH3 emissions was a function of TAN concentration, decreasing in intensity at higher TAN and approaching rates comparable to the pure solutions of AS. The difference in emissions with solutions of equivalent TAN suggests a synergistic mechanism that is enhancing NH3 emissions in SPL and SLL. Concurrent measurements as part of the National Air Emissions Monitoring Study at the swine operations originally sampled for SPL and SLL document the emissions of CO2, H2S and VOCs (primarily acetic, propionic and butyric acids) at levels that are comparable to observed NH3 emissions. To date, only additions of NaHCO3 to the SPL and SLL have been found to enhance NH3 emissions and exhibit the same response to increasing TAN as exhibited by the original SPL and SLL solutions. Possible reactions that could enhance emissions will be discussed.

Efficient control system for low-concentration inorganic gases from a process vent stream: application of surfactants in spray and packed columns.

PubMed

Chein, Hungmin; Aggarwal, Shankar G; Wu, Hsin-Hsien

2004-11-01

Control of low-concentration pollutants from a semiconductor process vent stream using a wet-scrubbing technique is a challenging task to meet Taiwan environmental emission standards. An efficient wet-scrubber is designed on a pilot scale and tested to control low concentration acid and base waste-gas emission. The scrubber system consisted of two columns, i.e., a fine spray column [cutoff diameter (based on volume), Dv(50) = 15.63 microm; Sauter mean diameter (SMD) = 7.62 microm], which is especially efficient for NH3 removal as the pH of the spraying liquid is approximately 7 followed by a packed column with a scrubbing liquid pH approximately 9.0 mainly for acids removal. It is observed that use of the surfactants in low concentration about 10(-4) M and 10(-7) M in the spray liquid and in the scrubbing liquid, respectively, remarkably enhances the removal efficiency of the system. A traditional packed column (without the spray column and the surfactant) showed that the removal efficiencies of NH3, HF, and HCl for the inlet concentration range 0.2 to 3 ppm were (n = 5) 22.6+/-3.4%, 43.4+/-5.5%, and 40.4+/-7.4%, respectively. The overall efficiencies of the proposed system (the spray column and the packed column) in the presence of the surfactant in the spray liquid and in the scrubbing liquid forthese three species were found to increase significantly (n = 5) from 60.3+/-3.6 to 82.8+/-6.8%, 59.1+/-2.7 to 83.4+/-4.2%, and 56.2+/-7.3 to 81.0+/-6.7%, respectively. In this work, development of charge on the gas-liquid interface due to the surfactants has been measured and discussed. It is concluded that the presence of charge on the gas-liquid interface is the responsible factor for enhancement of the removal efficiency (mass-transfer in liquid phase). The effects of the type of surfactants, their chain length, concentration in liquid, etc. on the removal efficiency are discussed. Since the pilot tests were performed under the operating conditions similar to most of the wet-scrubbers operated in semiconductors manufacturing facilities for inorganic pollutants, this study can be applied to modify the existing wet-scrubbers to enhance the removal efficiencies, especially for low-concentration pollutants.

Energy intensity and the energy mix: what works for the environment?

PubMed

El Anshasy, Amany A; Katsaiti, Marina-Selini

2014-04-01

In the absence of carbon sequestration, mitigating carbon emissions can be achieved through a mix of two broad policy approaches: (i) reducing energy intensity by improving energy efficiency and conservation, and (ii) changing the fuel mix. This paper investigates the long-run relationship between energy intensity, the energy mix, and per capita carbon emissions; while controlling for the level of economic activity, the economic structure measured by the relative size of the manufacturing sector, and the differences in institutional qualities across countries. We aim to answer two particularly important policy questions. First, to what extent these policy approaches are effective in mitigating emissions in the long-run? Second, which institutional qualities significantly contribute to better long-run environmental performance? We use historical data for 131 countries in a heterogeneous panel framework for the period 1972-2010. We find that less dependence on fossil fuel and lower energy intensity reduce emissions in the long run. A goal of 10% reduction in CO2 levels in the long-run requires reducing the share of fossil fuel in total energy use by 11%, or reducing energy intensity by 13%. In addition, specific institutional qualities such as better corruption control and judiciary independence contribute to mitigating levels of emissions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Emission Characteristics of A P and W Axially Staged Sector Combustor

NASA Technical Reports Server (NTRS)

He, Zhuohui J.; Wey, Changlie; Chang, Clarence T.; Lee, Chi Ming; Surgenor, Angela D.; Kopp-Vaughan, Kristin; Cheung, Albert

2016-01-01

Emission characteristics of a three-cup P and W Axially Controlled Stoichiometry (ACS) sector combustor are reported in this article. Multiple injection points and fuel staging strategies are used in this combustor design. Pilot-stage injectors are located on the front dome plate of the combustor, and main-stage injectors are positioned on the top and bottom of the combustor liners downstream. Low power configuration uses only pilot-stage injectors. Main-stage injectors are added to high power configuration to help distribute fuel more evenly and achieve overall lean burn yielding very low NOx emissions. Combustion efficiencies at four ICAO LTO conditions were all above 99%. Three EINOx emissions correlation equations were developed based on the experimental data to describe the NOx emission trends of this combustor concept. For the 7% and 30% engine power conditions, NOx emissions are obtained with the low power configuration, and the EINOx values are 6.16 and 6.81. The high power configuration was used to assess 85% and 100% engine power NOx emissions, with measured EINOx values of 4.58 and 7.45, respectively. The overall landing-takeoff cycle NOx emissions are about 12% relative to ICAO CAEP/6 level.

Generation of methane from paddy fields and cattle in India, and its reduction at source

NASA Astrophysics Data System (ADS)

Bandyopadhyay, T. K.; Goyal, P.; Singh, M. P.

Methane (CH4) is a saturated organic gas. About 500 Tg yr -1 methane is generated globally. It is evident that 70% of the total emission have anthropogenic sources. The paddy fields contribute a significant portion of the total methane generated. About 20% of the total methane is generated from the paddy fields. In India, methane efflux rate is negative to 49 mg m -2 hr -1. The mean CH4 flux from Indian paddy fields is calculated to be 4.0 Tgyr -1. Livestock, and in particular ruminants are one of the important sources of methane emission on a global scale. There are two sources of methane emission from live stock: (1) from digestive process of ruminants, (2) from animal wastes. The estimated value of methane emission from digestive process of ruminants in India accounts for 6.47 Tgyr -1, and animal wastes accounts for 1.60 Tgyr -1. Total generation of methane from animals in India is about 8.0 Tg yr -1 . In paddy fields the key of controlling methane emission lies in the control of irrigation water. The methane emission can be decreased drastically if the field is under dry conditions for a few days at the end of tillering. In the case of livestock, reduction of methane emission can be done by (1) increasing the intake of the animal, (2) modifying the composition of the diet, (3) eliminating protozoa in rumen, (4) improving fibre digestion efficiency and (5) inhibiting activity of methanogenic bacteria.

Spectral tuning of optical coupling between air-mode nanobeam cavities and individual carbon nanotubes

NASA Astrophysics Data System (ADS)

Machiya, Hidenori; Uda, Takushi; Ishii, Akihiro; Kato, Yuichiro K.

Air-mode nanobeam cavities allow for high efficiency coupling to air-suspended carbon nanotubes due to their unique mode profile that has large electric fields in air. Here we utilize heating-induced energy shift of carbon nanotube emission to investigate the cavity quantum electrodynamics effects. In particular, we use laser-induced heating which causes a large blue-shift of the nanotube photoluminescence as the excitation power is increased. Combined with a slight red-shift of the cavity mode at high powers, detuning of nanotube emission from the cavity can be controlled. We estimate the spontaneous emission coupling factor β at different spectral overlaps and find an increase of β factor at small detunings, which is consistent with Purcell enhancement of nanotube emission. Work supported by JSPS (KAKENHI JP26610080, JP16K13613), Asahi Glass Foundation, Canon Foundation, and MEXT (Photon Frontier Network Program, Nanotechnology Platform).

40 CFR Appendix Ix to Part 266 - Methods Manual for Compliance With the BIF Regulations

Code of Federal Regulations, 2010 CFR

2010-07-01

... Systems 2.1Performance Specifications for Continuous Emission Monitoring of Carbon Monoxide and Oxygen for... Methodology for Bevill Residue Determinations 8.0Procedures for Determining Default Values for Air Pollution Control System Removal Efficiencies 8.1APCS RE Default Values for Metals 8.2APCS RE Default Values for HC1...

40 CFR Appendix Ix to Part 266 - Methods Manual for Compliance With the BIF Regulations

Code of Federal Regulations, 2011 CFR

2011-07-01

... Systems 2.1Performance Specifications for Continuous Emission Monitoring of Carbon Monoxide and Oxygen for... Methodology for Bevill Residue Determinations 8.0Procedures for Determining Default Values for Air Pollution Control System Removal Efficiencies 8.1APCS RE Default Values for Metals 8.2APCS RE Default Values for HC1...

40 CFR Appendix A to Part 75 - Specifications and Test Procedures

Code of Federal Regulations, 2011 CFR

2011-07-01

...-1b in section 2.1.1.1 of this appendix. RE = Expected average design removal efficiency of control... 40 Protection of Environment 16 2011-07-01 2011-07-01 false Specifications and Test Procedures A... (CONTINUED) CONTINUOUS EMISSION MONITORING Pt. 75, App. A Appendix A to Part 75—Specifications and Test...

40 CFR 63.4362 - How do I determine the add-on control device emission destruction or removal efficiency?

Code of Federal Regulations, 2011 CFR

2011-07-01

... applicable, during each test run. (b) Measure the volatile organic matter concentration as carbon at the... limit, only the outlet volatile organic matter concentration must be determined. The outlet volatile organic matter concentration is determined as the average of the three test runs. (1) Use Method 25 if the...

40 CFR 63.4362 - How do I determine the add-on control device emission destruction or removal efficiency?

Code of Federal Regulations, 2012 CFR

2012-07-01

... applicable, during each test run. (b) Measure the volatile organic matter concentration as carbon at the... limit, only the outlet volatile organic matter concentration must be determined. The outlet volatile organic matter concentration is determined as the average of the three test runs. (1) Use Method 25 if the...

40 CFR 63.4362 - How do I determine the add-on control device emission destruction or removal efficiency?

Code of Federal Regulations, 2013 CFR

2013-07-01

... applicable, during each test run. (b) Measure the volatile organic matter concentration as carbon at the... limit, only the outlet volatile organic matter concentration must be determined. The outlet volatile organic matter concentration is determined as the average of the three test runs. (1) Use Method 25 if the...

40 CFR 63.4362 - How do I determine the add-on control device emission destruction or removal efficiency?

Code of Federal Regulations, 2014 CFR

2014-07-01

... applicable, during each test run. (b) Measure the volatile organic matter concentration as carbon at the... limit, only the outlet volatile organic matter concentration must be determined. The outlet volatile organic matter concentration is determined as the average of the three test runs. (1) Use Method 25 if the...

Coal-fired boiler houses in Cracow present state and possibilities to improve their efficiency

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cyklis, P.; Butcher, T.A.

1995-12-31

A significant amount of heat energy both for heating and process purposes is generated in Cracow, Poland in small-and medium size local boiler houses. The operating procedure of these boiler houses is most often economically and ecologically ineffective because of the bad condition of boilers and lack of funds to install automation, control and measurement equipment. Within the Polish-American Program of Elimination of Low Emission Sources financed by the US Department of Energy, the ENERGOEKSPERT Co., Ltd. investigated chosen boiler houses in Cracow, commissioned by the Cracow Development Office. The results of these investigations were subject of engineering analysis carriedmore » out at the Institute of Industrial Equipment and Power Engineering, Technical University, Cracow. The analysis proved that the low-cost improvement of economic efficiency and reduction of air pollutant emission is feasible for combustion of coal fuels.« less

Commissioning and Performance Analysis of WhisperGen Stirling Engine

NASA Astrophysics Data System (ADS)

Pradip, Prashant Kaliram

Stirling engine based cogeneration systems have potential to reduce energy consumption and greenhouse gas emission, due to their high cogeneration efficiency and emission control due to steady external combustion. To date, most studies on this unit have focused on performance based on both experimentation and computer models, and lack experimental data for diversified operating ranges. This thesis starts with the commissioning of a WhisperGen Stirling engine with components and instrumentation to evaluate power and thermal performance of the system. Next, a parametric study on primary engine variables, including air, diesel, and coolant flowrate and temperature were carried out to further understand their effect on engine power and efficiency. Then, this trend was validated with the thermodynamic model developed for the energy analysis of a Stirling cycle. Finally, the energy balance of the Stirling engine was compared without and with heat recovery from the engine block and the combustion chamber exhaust.

Air ionization as a control technology for off-gas emissions of volatile organic compounds.

PubMed

Kim, Ki-Hyun; Szulejko, Jan E; Kumar, Pawan; Kwon, Eilhann E; Adelodun, Adedeji A; Reddy, Police Anil Kumar

2017-06-01

High energy electron-impact ionizers have found applications mainly in industry to reduce off-gas emissions from waste gas streams at low cost and high efficiency because of their ability to oxidize many airborne organic pollutants (e.g., volatile organic compounds (VOCs)) to CO 2 and H 2 O. Applications of air ionizers in indoor air quality management are limited due to poor removal efficiency and production of noxious side products, e.g., ozone (O 3 ). In this paper, we provide a critical evaluation of the pollutant removal performance of air ionizing system through comprehensive review of the literature. In particular, we focus on removal of VOCs and odorants. We also discuss the generation of unwanted air ionization byproducts such as O 3 , NOx, and VOC oxidation intermediates that limit the use of air-ionizers in indoor air quality management. Copyright © 2017. Published by Elsevier Ltd.

Phosphor-free nanopyramid white light-emitting diodes grown on (101{sup ¯}1) planes using nanospherical-lens photolithography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Kui; Department of Electronic Engineering, Tsinghua National Laboratory for Information Science and Technology/State Key Lab on Integrated Optoelectronics, Tsinghua University, Beijing 100084; Wei, Tongbo, E-mail: tbwei@semi.ac.cn

2013-12-09

We reported a high-efficiency and low-cost nano-pattern method, the nanospherical-lens photolithography technique, to fabricate a SiO{sub 2} mask for selective area growth. By controlling the selective growth, we got a highly ordered hexagonal nanopyramid light emitting diodes with InGaN/GaN quantum wells grown on nanofacets, demonstrating an electrically driven phosphor-free white light emission. We found that both the quantum well width and indium incorporation increased linearly along the (101{sup ¯}1) planes towards the substrate and the perpendicular direction to the (101{sup ¯}1) planes as well. Such spatial distribution was responsible for the broadband emission. Moreover, using cathodoluminescence techniques, it was foundmore » that the blue emission originated from nanopyramid top, resembling the quantum dots, green emission from the InGaN quantum wells layer at the middle of sidewalls, and yellow emission mainly from the bottom of nanopyramid ridges, similar to the quantum wires.« less

Bioelectrochemical approach for control of methane emission from wetlands.

PubMed

Liu, Shentan; Feng, Xiaojuan; Li, Xianning

2017-10-01

To harvest electricity and mitigate methane emissions from wetlands, a novel microbial fuel cell coupled constructed wetland (MFC-CW) was assembled with an anode placing in the rhizosphere and a cathode on the water surface. Plant-mediated methane accounted for 71-82% of the total methane fluxes. The bioanode served as an inexhaustible source of electron acceptors and resulted in reduced substantial methane emissions owing to electricigens outcompeting methanogens for carbon and electrons when substrate was deficient. However, when supplying sufficient organic carbon, both electricity and methane increased, indicating that electrogenesis and methanogenesis could co-exist in harmony. Direct methane emission (diffusion/ebullition) and plant-mediated methane emission were affected by operating conditions. Methanogenesis was significantly suppressed (∼98%) at HRT of 96h and with external resistance of 200Ω, accompanied with improved coulombic efficiency of 14.9% and current density of 187mA/m 2 . Contrarily, change of electrode polarity in the rhizosphere led to more methane efflux. Copyright © 2017 Elsevier Ltd. All rights reserved.

Photon correlation study of background suppressed single InGaN nanocolumns

NASA Astrophysics Data System (ADS)

Yamamoto, Takatoshi; Maekawa, Michiru; Imanishi, Yusuke; Ishizawa, Shunsuke; Nakaoka, Toshihiro; Kishino, Katsumi

2016-04-01

We report on a linearly polarized non-classical light emission from a single InGaN/GaN nanocolumn, which is a site-controlled nanostructure allowing for pixel-like large-scale integration. We have developed a shadow mask technique to reduce background emissions arising from nitride deposits around single nanocolumns and defect states of GaN. The signal to background ratio is improved from 0.5:1 to 10:1, which allows for detailed polarization-dependent measurement and photon-correlation measurements. Polarization-dependent measurements show that linearly polarized emissions arise from excitonic recombination involving a heavy-hole-like electronic state, corresponding to the bulk exciton of an in-plane polarized A exciton. The second-order coherence function at time zero g (2)(0) is 0.52 at 20 K without background correction. This value is explained in terms of a statistical mixture of a single-photon emission with residual weak background emissions, as well as efficient carrier injection from other localized states.

Fabrication of highly efficient ZnO nanoscintillators

NASA Astrophysics Data System (ADS)

Procházková, Lenka; Gbur, Tomáš; Čuba, Václav; Jarý, Vítězslav; Nikl, Martin

2015-09-01

Photo-induced synthesis of high-efficiency ultrafast nanoparticle scintillators of ZnO was demonstrated. Controlled doping with Ga(III) and La(III) ions together with the optimized method of ZnO synthesis and subsequent two-step annealing in air and under reducing atmosphere allow to achieve very high intensity of UV exciton luminescence, up to 750% of BGO intensity magnitude. Fabricated nanoparticles feature extremely short sub-nanosecond photoluminescence decay times. Temperature dependence of the photoluminescence spectrum within 8-340 K range was investigated and shows the absence of visible defect-related emission within all temperature intervals.

A Graph Based Approach to Nonlinear Model Predictive Control with Application to Combustion Control and Flow Control

DTIC Science & Technology

2015-08-21

plants (200 MW and above) produce the majority of the nation’s energy demands, and these are the most heavily regulated by the EPA . The automotive...existing engines are not achieving the best possible efficiency. As in the electric power industry, EPA regulation is a major factor in the US...automotive engine market. Cummins, for example, was the only company in the market to meet the 2010 EPA standards for NOx emissions with their release of a 6.7