162 Matching Results

Results open in a new window/tab.

Laser Scanning Confocal Microscopic Investigations of Simulated Nuclear Waste Structures (open access)

Laser Scanning Confocal Microscopic Investigations of Simulated Nuclear Waste Structures

Researchers at the Department of Energy's Savannah River Technology Center are using advanced microscopy techniques to understand the effects of trace organic chemical additions on nuclear waste slurry flow properties. Trace organic chemicals, surfactants (rheology modifiers), are being used in all types of industries to modify the flow properties of various commercial chemicals. Nuclear waste treatment at the Department of Energy's weapons production facilities, Savannah River Site and Hanford Reservation, is limited by the viscosity of the nuclear waste slurries as the material is processed through a variety of waste treatment and immobilization processes. The picture was taken using a laser scanning confocal microscope.
Date: November 24, 2003
Creator: Calloway, T.B.
System: The UNT Digital Library
A Binary Segmentation Approach for Boxing Ribosome Particles in Cryo EM Micrographs (open access)

A Binary Segmentation Approach for Boxing Ribosome Particles in Cryo EM Micrographs

Three-dimensional reconstruction of ribosome particles from electron micrographs requires selection of many single-particle images. Roughly 100,000 particles are required to achieve approximately 10 angstrom resolution. Manual selection of particles, by visual observation of the micrographs on a computer screen, is recognized as a bottleneck in automated single particle reconstruction. This paper describes an efficient approach for automated boxing of ribosome particles in micrographs. Use of a fast, anisotropic non-linear reaction-diffusion method to pre-process micrographs and rank-leveling to enhance the contrast between particles and the background, followed by binary and morphological segmentation constitute the core of this technique. Modifying the shape of the particles to facilitate segmentation of individual particles within clusters and boxing the isolated particles is successfully attempted. Tests on a limited number of micrographs have shown that over 80 percent success is achieved in automatic particle picking.
Date: June 24, 2003
Creator: Adiga, Umesh P. S.; Malladi, Ravi; Baxter, William & Glaeser, Robert M.
System: The UNT Digital Library
ENSURING THE AVAILABILITY AND RELIABILITY OF UREA DOSING FOR ON-ROAD AND NON-ROAD (open access)

ENSURING THE AVAILABILITY AND RELIABILITY OF UREA DOSING FOR ON-ROAD AND NON-ROAD

The purpose of this presentation is to address two important issues. The first issue is nationwide availability of urea. The second is assurance by the engine maker that the engine cannot operate without urea. In regard to the first issue, North American urea production can support SCR needs for the Heavy Duty truck industry. The existing distribution methods, pathways and technology could be utilized for urea supply with no new invention required. Urea usage and storage capacity on vehicles would support long distances between tank refills, as SCR could be initially rolled out with a limited infrastructure. The price of urea should be less than diesel fuel and urea SCR should have a fuel economy advantage over competing technologies. It can be in place by 2007. In regard to the second issue, sensor technology exists to monitor urea tank level and verify that the fluid in the tank is urea. NOx sensors are available to monitor tailpipe NOx, ensuring the entire SCR system is functioning properly, and inferring that urea is in the system. The monitoring system could be used to monitor compliance, record faults, and initiate enforcement actions as necessary. The monitoring system could initiate actions to encourage compliance.
Date: August 24, 2003
Creator: Barton, G & Lonsdale, B
System: The UNT Digital Library
Transient, Real-Time, Particulate Emission Measurements in Diesel Engines (open access)

Transient, Real-Time, Particulate Emission Measurements in Diesel Engines

This paper reports our efforts to develop an instrument, TG-1, to measure particulate emissions from diesel engines in real-time. TG-1 while based on laser-induced incandescence allows measurements at 10 Hz on typical engine exhausts. Using such an instrument, measurements were performed in the exhaust of a 1.7L Mercedes Benz engine coupled to a low inertia dynamometer. Comparative measurements performed under engine steady state conditions showed the instrument to agree within {+-}12% of measurements performed with an SMPS. Moreover, the instrument had far better time response and time resolution than a TEOM{reg_sign} 1105. Also, TG-1 appears to surpass the shortcomings of the TEOM instrument, i.e., of yielding negative values under certain engine conditions and, being sensitive to external vibration.
Date: August 24, 2003
Creator: Gupta, S.; Shih, J.; Hillman, G.; Sekar, R.; Graze, R.; Shimpi, S. et al.
System: The UNT Digital Library
USE OF A DIESEL FUEL PROCESSOR FOR RAPID AND EFFICIENT REGENERATION OF SINGLE LEG NOX ADSORBER SYSTEMS (open access)

USE OF A DIESEL FUEL PROCESSOR FOR RAPID AND EFFICIENT REGENERATION OF SINGLE LEG NOX ADSORBER SYSTEMS

Lean NOx adsorber systems are one of the primary candidate technologies for the control of NOx from diesel engines to meet the 2007-2010 US emissions regulations, which require a 90% reduction of NOx from the 2004 regulations. Several of the technical challenges facing this technology are regeneration at low exhaust temperatures and the efficient use of diesel fuel to minimize fuel penalty. A diesel processor system has been developed and tested in a single leg NOx adsorber configuration on a diesel engine test stand. During NOx adsorber regeneration, this fuel processor system performs reduces the exhaust O2 level to zero and efficiently processes the diesel fuel to H2 and CO. Combined with a Nox adsorber catalyst, this system has demonstrated NOx reduction above 90%, regeneration of the NOx adsorber H2/CO pulses as short as 1 second and fuel penalties in the 3 to 4% range at 50% load. This fuel processor system can also be used to provide the desulfation cycle required with sulfur containing fuels as well as providing thermal management for PM filter regeneration.
Date: August 24, 2003
Creator: Betta, R; Cizeron, J; Sheridan, D & Davis, T
System: The UNT Digital Library
Deuteron photodissociation in ultraperipheral relativistic heavy-ion on deuteron collisions (open access)

Deuteron photodissociation in ultraperipheral relativistic heavy-ion on deuteron collisions

None
Date: March 24, 2003
Creator: Klein, Spencer & Vogt, Ramona
System: The UNT Digital Library
Using Hydro-Cutting to Aid in Remediation of a Firing Range Contaminated with Depleted Uranium (open access)

Using Hydro-Cutting to Aid in Remediation of a Firing Range Contaminated with Depleted Uranium

This paper describes the challenges encountered in decommissioning a firing range that had been used to test fire depleted uranium rounds in the late 1950's and early 1960's. The paper details the operational challenges and innovative solutions involved in remediating and decommissioning a firing range bullet catcher once unexploded ordnance was discovered. It also discusses how the Army dealt with an intertwining web of regulatory and permit issues that arose in treating and disposing of multiple waste streams. The paper will show how the use of a Resource Conservation and Recovery Act (RCRA) Temporary Authorization allowed the Army to deal with the treatment of a variety of waste streams and how hydro-cutting process was used to demilitarize the potentially unexploded rounds.
Date: February 24, 2003
Creator: Styvaert, Michael S.; Conley, Richard D. & Watters, David J.
System: The UNT Digital Library
The Worker Component At The World Trade Center Cleanup: Addressing Cultural And Language Differences In Emergency Operations (open access)

The Worker Component At The World Trade Center Cleanup: Addressing Cultural And Language Differences In Emergency Operations

On September 11, 2001, the terrorist attacks on the World Trade Center (WTC) caused astronomical loss of life and property. Systems in place to manage disaster response were strained to the limit because key first responders were among the casualties when the twin towers collapsed. In addition, the evolution of events required immediate response in a rapidly changing and extremely hazardous situation. Rescue, recovery, and clean up became an overpowering and sustained effort that would utilize the resources of federal, state and local governments and agencies. One issue during the response to the WTC disaster site that did not receive much attention was that of the limited and non-English speaking worker. The Operating Engineers National HAZMAT Program (OENHP), with its history of a Hispanic Outreach Program, was acutely aware of this issue with the Hispanic worker. The Hispanic population comprises approximately 27% of the population of New York City (1). The extremely unfortunate and tragic events of that day provided an opportunity to not only provide assistance for the Hispanic workers, but also to apply lessons learned and conduct studies on worker training with language barriers in a real life environment. However, due to the circumstances surrounding this tragedy, the …
Date: February 24, 2003
Creator: McCabe, B.; Carpenter, C. & D., Blair.
System: The UNT Digital Library
Key Performance Criteria Affecting the Most the Safety of a Nuclear Waste Long Term Storage : A Case Study Commissioned by CEA (open access)

Key Performance Criteria Affecting the Most the Safety of a Nuclear Waste Long Term Storage : A Case Study Commissioned by CEA

As part of the work scope set in the French law on high level long lived waste R&D passed in 1991, CEA is conducting a research program to establish the scientific basis and assess the feasibility of long term storage as an option for the safe management of nuclear waste for periods as long as centuries. This goal is a significant departure from the current industrial practice where storage facilities are usually built to last only a few decades. From a technical viewpoint such an extension in time seems feasible provided care and maintenance is exercised. Considering such long periods of time, the risk for Society of loosing oversight and control of such a facility is real, which triggers the question of whether and how long term storage safety can be actually achieved. Therefore CEA commissioned a study (1) in which MUTADIS Consultants (2) and CEPN (3) were both involved. The case study looks into several past and actual human enterprises conducted over significant periods o f time, one of them dating back to the end of the 18th century, and all identified out of the nuclear field. Then-prevailing societal behavior and organizational structures are screened out to show how …
Date: February 24, 2003
Creator: Marvy, A.; Lioure, A; Heriard-Dubreuil, G.; Gadbois, S.; Schneider, T. & Schieber, C.
System: The UNT Digital Library
Non-thermal plasma based technologies for the after-treatment of automotive exhaust particulates and marine diesel exhaust NOx (open access)

Non-thermal plasma based technologies for the after-treatment of automotive exhaust particulates and marine diesel exhaust NOx

The trend in environmental legislation is such that primary engine modifications will not be sufficient to meet all future emissions requirements and exhaust aftertreatment technologies will need to be employed. One potential solution that is well placed to meet those requirements is non-thermal plasma technology. This paper will describe our work with some of our partners in the development of a plasma based diesel particulate filter (DPF) and plasma assisted catalytic reduction (PACR) for NOx removal. This paper describes the development of non-thermal plasma technology for the aftertreatment of particulates from a passenger car engine and NOx from a marine diesel exhaust application.
Date: August 24, 2003
Creator: McAdams, R.; Beech, P.; Gillespie, R.; Guy, C.; Jones, S.; Liddell, T. et al.
System: The UNT Digital Library
Lessons Learned at Envirocare of Utah's Containerized Waste Facility (CWF): Dose Minimization Through ALARA Techniques and Tools (open access)

Lessons Learned at Envirocare of Utah's Containerized Waste Facility (CWF): Dose Minimization Through ALARA Techniques and Tools

Envirocare of Utah, Inc. (Envirocare) commenced operation of its Class A Containerized Waste Facility (CWF) on October 25, 2001. The opening of this facility began a new era for Envirocare, in that; their core business had always been low level, high volume, bulk radioactive waste. The CWF commenced operations to dispose of low level, low volume, high activity, containerized radioactive waste. Due to the potential for high dose rates on the waste disposal containers, the ALARA principle (As Low As Reasonably Achievable) plays an important role in the operation of the CWF and its mission to properly dispose of waste while minimizing doses to the workers, public, and the environment. This paper will enumerate some of the efforts made by the management and staff of the CWF that have contributed to significant dose reductions.
Date: February 24, 2003
Creator: Heckman, J.; Gardner, J. & Ledoux, M. R.
System: The UNT Digital Library
The Murmansk Initiative-RF: Completion (open access)

The Murmansk Initiative-RF: Completion

The Murmansk Initiative-RF (MI) was conceived to provide the Russian Federation (RF) with the capacity to manage low-level liquid radioactive waste (LLRW) and comply with the requirements of the London Convention that prohibit ocean dumping of these wastes. The Initiative, under a trilateral agreement begun in 1994/95, has upgraded an existing low-level liquid radioactive waste treatment facility, increased its capacity from 1,200 m3 /year to 5,000 m3 /year, and expanded the capability of the facility to treat liquids containing salt (up to 20 g/L). The three parties to the agreement, the Russian Federation, Norway, and the United States, have split the costs for the project. It was the first project of its kind to utilize exclusively Russian subcontractors in the upgrade and expansion of the LLRW treatment plant on the premises of FGUP Atomflot (now FGUP Atomflot) in Murmansk, Russia. The project advanced into the test-operation phase. These start-up activities have include d processing of actual radioactive liquid waste from the Arctic icebreaker fleet, and incorporation of these wastes into a cementation process of Russian design. Initial runs have revealed that procedures for unloading spent ion-exchange sorbents need to be improved and that sludges formed during removal of alkaline-earth metals …
Date: February 24, 2003
Creator: Czajkowski, C.; Wester, D. W.; Dyer, R. S.; Sorlie, A. A. & Moller, B.
System: The UNT Digital Library
Solidification/Stabilization of Elemental Mercury Waste by Amalgamation (open access)

Solidification/Stabilization of Elemental Mercury Waste by Amalgamation

Experiments on solidification of elemental mercury waste were conducted by amalgamation with several metal powders such as copper, zinc, tin, brass and bronze. Unlike the previous studies which showed a dispersible nature after solidification, the waste forms were found to possess quite large compressive strengths in both copper and bronze amalgam forms. The durability was also confirmed by showing very minor changes of strength after 90 days of water immersion. Leachability from the amalgam forms is also shown to be low: measured mercury concentration in the leachate by the Toxicity Characteristic Leaching Procedure (TCLP) was well below the Environmental Protection Agency (EPA) limit. Long term leaching behavior by Accelerated Leach Test (ALT) has shown that the leaching process was dominated by diffusion and the effective diffusion coefficient was quite low (around 10-19 cm2/sec). The mercury vapor concentration from the amalgam forms were reduced to a 20% level of that for elemental mercury and to one-hundredth after 3 months.
Date: February 24, 2003
Creator: Yim, S. P.; Ahn, B. G.; Lee, H. J.; Shon, J. S.; Chung, H.; Kim, K. J. et al.
System: The UNT Digital Library
POTENTIAL THERMOELECTRIC APPLICATIONS IN DIESEL VEHICLES (open access)

POTENTIAL THERMOELECTRIC APPLICATIONS IN DIESEL VEHICLES

Novel thermodynamic cycles developed by BSST provide improvements by factors of approximately 2 in cooling, heating and power generation efficiency of solid-state thermoelectric systems. The currently available BSST technology is being evaluated in automotive development programs for important new applications. Thermoelectric materials are likely to become available that further increase performance by a comparable factor. These major advancements should allow the use of thermoelectric systems in new applications that have the prospect of contributing to emissions reduction, fuel economy, and improved user comfort. Potential applications of thermoelectrics in diesel vehicles are identified and discussed. As a case in point, the history and status of the Climate Controlled Seat (CCS) system from Amerigon, the parent of BSST, is presented. CCS is the most successful and highest production volume thermoelectric system in vehicles today. As a second example, the results of recent analyses on electric power generation from vehicle waste heat are discussed. Conclusions are drawn as to the practicality of waste power generation systems that incorporate BSST's thermodynamic cycle and advanced thermoelectric materials.
Date: August 24, 2003
Creator: Crane, D
System: The UNT Digital Library
Status of the NRC Decommissioning Program (open access)

Status of the NRC Decommissioning Program

On July 21, 1997, the U.S. Nuclear Regulatory Commission (NRC) published the final rule on Radiological Criteria for License Termination (the License Termination Rule or LTR) as Subpart E to 10 CFR Part 20. NRC regulations require that materials licensees submit Decommissioning Plans to support the decommissioning of its facility if it is required by license condition, or if the procedures and activities necessary to carry out the decommissioning have not been approved by NRC and these procedures could increase the potential health and safety impacts to the workers or the public. NRC regulations also require that reactor licensees submit Post-shutdown Decommissioning Activities Reports and License Termination Plans to support the decommissioning of nuclear power facilities. This paper provides an update on the status of the NRC's decommissioning program that was presented during WM'02. It discusses the staff's current efforts to streamline the decommissioning process, current issues being faced in the decommissioning program, such as partial site release and restricted release of sites, as well as the status of the decommissioning of complex sites and those listed in the Site Decommissioning Management Plan. The paper discusses the status of permanently shut-down commercial power reactors and the transfer of complex decommissioning …
Date: February 24, 2003
Creator: Orlando, D. A.; Camper, L.; Buckley, J.; Pogue, E. & Banovac, K.
System: The UNT Digital Library
Visibility Trends for Coastal Regions (open access)

Visibility Trends for Coastal Regions

Increased biomass burning (e.g., forest fires, controlled burns, etc.) and anthropogenic emissions into the earth's atmosphere in the past century have led to much debate with regard to greenhouse gases, atmospheric carbon buildup, aerosol increases, and global warming. Atmospheric aerosols are linked to reduced air quality and visibility (V) in many parts of the world. In south-central South Carolina visibility reduction has been responsible for traffic fatalities on public highways, with resulting lawsuits against governmental entities. Congress passed the Clean Air Act in 1963, with amendments in 1970, 1977, and 1990 to improve air quality. The actual implementation of the Clean Air Act has been an intermittent process because of litigation over some provisions of the Act. However, it is reasonable to assume that visibility has improved in the U.S. over the past decades due to implementation of the Clean Air Act's provisions. In this study visibility data have been acquired for seven weather stations along or near the U.S. East Coast to study how conditions have changed from the 1980s to the 1990s.
Date: November 24, 2003
Creator: Weber, A. H.
System: The UNT Digital Library
Using bitmap index for interactive exploration of large datasets (open access)

Using bitmap index for interactive exploration of large datasets

Many scientific applications generate large spatio-temporal datasets. A common way of exploring these datasets is to identify and track regions of interest. Usually these regions are defined as contiguous sets of points whose attributes satisfy some user defined conditions, e.g. high temperature regions in a combustion simulation. At each time step, the regions of interest may be identified by first searching for all points that satisfy the conditions and then grouping the points into connected regions. To speed up this process, the searching step may use a tree based indexing scheme, such as a kd-tree or an octree. However, these indices are efficient only if the searches are limited to one or a small number of selected attributes. Scientific datasets often contain hundreds of attributes and scientists frequently study these attributes incomplex combinations, e.g. finding regions of high temperature yet low shear rate and pressure. Bitmap indexing is an efficient method for searching on multiple criteria simultaneously. We apply a bitmap compression scheme to reduce the size of the indices. In addition, we show that the compressed bitmaps can be used efficiently to perform the region growing and the region tracking operations. Analyses show that our approach scales well and …
Date: April 24, 2003
Creator: Wu, Kesheng; Koegler, Wendy; Chen, Jacqueline & Shoshani, Arie
System: The UNT Digital Library
Strategic Program Planning Lessons Learned In Developing The Long-Term Stewardship Science and Technology Roadmap (open access)

Strategic Program Planning Lessons Learned In Developing The Long-Term Stewardship Science and Technology Roadmap

Technology roadmapping is a strategic planning method used by companies to identify and plan the development of technologies necessary for new products. The U.S. Department of Energy's Office of Environmental Management has used this same method to refine requirements and identify knowledge and tools needed for completion of defined missions. This paper describes the process of applying roadmapping to clarify mission requirements and identify enhancing technologies for the Long-Term Stewardship (LTS) of polluted sites after site cleanup has been completed. The nature of some contamination problems is such that full cleanup is not achievable with current technologies and some residual hazards remain. LTS maintains engineered contaminant barriers and land use restriction controls, and monitors residual contaminants until they no longer pose a risk to the public or the environment. Roadmapping was used to clarify the breadth of the LTS mission, to identify capability enhancements needed to improve mission effectiveness and efficiency, and to chart out the research and development efforts to provide those enhancements. This paper is a case study of the application of roadmapping for program planning and technical risk management. Differences between the planned and actual application of the roadmapping process are presented along with lessons learned. Both …
Date: April 24, 2003
Creator: Dixon, B. W.; Hanson, D. J. & Matthern, G. E.
System: The UNT Digital Library
Characterization of high-power lithium-ion cells during constant current cycling. Part I. Cycle performance and electrochemical diagnostics (open access)

Characterization of high-power lithium-ion cells during constant current cycling. Part I. Cycle performance and electrochemical diagnostics

Twelve-cm{sup 2} pouch type lithium-ion cells were assembled with graphite anodes, LiNi{sub 0.8}Co{sub 0.15}Al{sub 0.05}O{sub 2} cathodes and 1M LiPF{sub 6}/EC/DEC electrolyte. These pouch cells were cycled at different depths of discharge (100 percent and 70 percent DOD) at room temperature to investigate cycle performance and pulse power capability. The capacity loss and power fade of the cells cycled over 100 percent DOD was significantly faster than the cell cycled over 70 percent DOD. The overall cell impedance increased with cycling, although the ohmic resistance from the electrolyte was almost constant. From electrochemical analysis of each electrode after cycling, structural and/or impedance changes in the cathode are responsible for most of the capacity and power fade, not the consumption of cycleable Li from side-reactions.
Date: January 24, 2003
Creator: Shim, Joongpyo & Striebel, Kathryn A.
System: The UNT Digital Library
Barrier RF stacking (open access)

Barrier RF stacking

This paper introduces a new method for stacking beams in the longitudinal phase space. It uses RF barriers to confine and compress beams in an accelerator, provided that the machine momentum acceptance is a few times larger than the momentum spread of the injected beam. This is the case for the Fermilab Main Injector. A barrier RF system employing Finemet cores and high-voltage solid-state switches is under construction. The goal is to double the number of protons per cycle on the production target for Run2 and NuMI experiments.
Date: February 24, 2003
Creator: Takagi, Weiren Chou and Akira
System: The UNT Digital Library
Evidence for light scalar resonances in charm meson decays from Fermilab E791 (open access)

Evidence for light scalar resonances in charm meson decays from Fermilab E791

From Dalitz-plot analyses of D{sup +} {yields} {pi}{sup -}{pi}{sup +}{pi}{sup +} and D{sup +} {yields} K{sup -}{pi}{sup +}{pi}{sup +} decays, we find evidence for light and broad scalar resonances {sigma}(500) and {kappa}(800). From a Dalitz-plot analysis of D{sub s}{sup +} {yields} {pi}{sup -}{pi}{sup +}{pi}{sup +} decays, they measure the masses and decay widths of the scalar resonances f{sub 0}(980) and f{sub 0}(1370).
Date: January 24, 2003
Creator: Schwartz, Alan J.
System: The UNT Digital Library
Focal-series reconstruction of nanoparticle exit-surface electron wave (open access)

Focal-series reconstruction of nanoparticle exit-surface electron wave

We have used the One-Angstrom Microscope (OAM) to image and apply focal-series reconstruction (FSR) of the exit-surface wave (ESW) to a 70Angstrom particle of gold supported on amorphous carbon. The phase of the complex ESW shows the positions of the atom columns in the specimen as white dots, and its diffractogram shows it contains information to 1.23Angstrom. The result demonstrates that through-focal reconstruction of the ESW does not need large crystal expanses to work properly. Although [110] Au structures may not need sub-Angstrom resolution to show all the useful structural details of the particle in this orientation, it is clear that focal reconstruction of the ESW can improve original data that is much more difficult to interpret directly. We expect this technique to prove even more useful when applied to nanoparticles containing finer spacings than the 2.35Angstrom separation of the 111 planes in the present gold nano-particle.
Date: February 24, 2003
Creator: O'Keefe, Michael A.; Nelson, E. Chris & Allard, Lawrence F.
System: The UNT Digital Library
Neutrino Factory R&D in the U.S. (open access)

Neutrino Factory R&D in the U.S.

We report here on the technical progress and R&D plans of the U.S. Neutrino Factory and Muon Collider Collaboration. Programs in targetry, cooling, acceleration, and simulations are covered. U.S. activities in support of the international Muon Ionization Cooling Experiment (MICE) are also described.
Date: September 24, 2003
Creator: Zisman, Michael S. & Collabo, for the Neutrino Factory and Muon Collider
System: The UNT Digital Library
BIFUNCTIONAL CATALYSTS FOR THE SELECTIVE CATALYTIC REDUCTION OF NO BY HYDROCARBONS (open access)

BIFUNCTIONAL CATALYSTS FOR THE SELECTIVE CATALYTIC REDUCTION OF NO BY HYDROCARBONS

Novel bifunctional catalysts combining two active phases, typically Cu-ZSM-5 and a modifier, were prepared and tested for the selective catalytic reduction of nitrogen oxides using propylene in order to overcome the hindering effects of water typically seen for single-phase catalysts such as Cu-ZSM-5. The catalysts were made by typical preparation techniques, but parameters could be varied to influence the catalyst. The physical characterization of the materials showed that the modification phase was added strictly to the external surface of the zeolite without hindering any internal surface area. Chemical characterization by temperature programmed reactions, DRIFTS and x-ray absorption spectroscopy indicated strong interaction between the two phases, primarily producing materials that exhibited lower reduction temperatures. Two improvements in NOx reduction activity (1000 ppm NO, 1000 ppm C3H6, 2% O2, 30,000 hr-1 GHSV) were seen for these catalysts compared with Cu- ZSM-5: a lower temperature of maximum NOx conversion activity (as low at 250 C), and an enhancement of activity when water was present in the system. The use of a second phase provides a way to further tune the properties of the catalyst in order to achieve mechanistic conditions necessary to maximize NOx remediation.
Date: August 24, 2003
Creator: Neylon, M.; Castagnola, M.; Kropf, A. & Marshall, C.
System: The UNT Digital Library