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Inevitability of Engine-Out Nox Emissions from Spark-Ignition and Diesel Engines (open access)

Inevitability of Engine-Out Nox Emissions from Spark-Ignition and Diesel Engines

Internal combustion engines, both spark ignition and Diesel, are dominant types of vehicle power sources and also provide power for other important stationary applications. Overall, these engines are a central part of power generation in modern society. However, these engines, burning hydrocarbon fuels from natural gas to gasoline and Diesel fuel, are also responsible for a great deal of pollutant emissions to the environment, especially oxides of nitrogen (NO{sub x}) and unburned hydrocarbons (UHC). In recent years, pollutant species emissions from internal combustion engines have been the object of steadily more stringent limitations from various governmental agencies. Engine designers have responded by developing engines that reduce emissions to accommodate these tighter limitations. However, as these limits become ever more stringent, the ability of engine design modifications to meet those limits must be questioned. Production of NO{sub x} in internal combustion engines is primarily due to the high temperature extended Zeldovich reaction mechanism: (1) O + N{sub 2} = NO + N; (2) N + O{sub 2} = NO + O; and (3) N + OH = NO + H. The rates of these reactions become significant when combustion temperatures reach or exceed about 2000K. This large temperature dependence, characterized by …
Date: January 11, 2000
Creator: Flynn, P F; Hunter, G L; Farrell, L A; Durrett, R P; Akinyemi, O C; Westbrook, C K et al.
Object Type: Article
System: The UNT Digital Library
Interger multiplication with overflow detection or saturation (open access)

Interger multiplication with overflow detection or saturation

High-speed multiplication is frequently used in general-purpose and application-specific computer systems. These systems often support integer multiplication, where two n-bit integers are multiplied to produce a 2n-bit product. To prevent growth in word length, processors typically return the n least significant bits of the product and a flag that indicates whether or not overflow has occurred. Alternatively, some processors saturate results that overflow to the most positive or most negative representable number. This paper presents efficient methods for performing unsigned or two's complement integer multiplication with overflow detection or saturation. These methods have significantly less area and delay than conventional methods for integer multiplication with overflow detection and saturation.
Date: January 11, 2000
Creator: Schulte, M.J.; Balzola, P.I.; Akkas, A. & Brocato, R.W.
Object Type: Article
System: The UNT Digital Library
[Official Transcript from the University of North Texas] (open access)

[Official Transcript from the University of North Texas]

An official transcript of an academic voyage at the University of North Texas, showcasing a comprehensive record of courses taken, grades earned, and academic achievements.
Date: January 11, 2000
Creator: unknown
Object Type: Text
System: The UNT Digital Library
The Oklahoma Daily (Norman, Okla.), Vol. 84, No. 81, Ed. 1 Tuesday, January 11, 2000 (open access)

The Oklahoma Daily (Norman, Okla.), Vol. 84, No. 81, Ed. 1 Tuesday, January 11, 2000

Student newspaper of the University of Oklahoma in Norman, Oklahoma that includes national, local, and campus news along with advertising.
Date: January 11, 2000
Creator: Wilmoth, Adam
Object Type: Newspaper
System: The Gateway to Oklahoma History
Perry Daily Journal (Perry, Okla.), Vol. 107, No. 7, Ed. 1 Tuesday, January 11, 2000 (open access)

Perry Daily Journal (Perry, Okla.), Vol. 107, No. 7, Ed. 1 Tuesday, January 11, 2000

Daily newspaper from Perry, Oklahoma that includes local, state, and national news along with advertising.
Date: January 11, 2000
Creator: Brown, Gloria
Object Type: Newspaper
System: The Gateway to Oklahoma History
Rains County Leader (Emory, Tex.), Vol. 112, No. 30, Ed. 1 Tuesday, January 11, 2000 (open access)

Rains County Leader (Emory, Tex.), Vol. 112, No. 30, Ed. 1 Tuesday, January 11, 2000

Weekly newspaper from Emory, Texas that includes local, state, and national news along with advertising.
Date: January 11, 2000
Creator: Hill, Earl Clyde, Jr.
Object Type: Newspaper
System: The Portal to Texas History
Sapulpa Daily Herald (Sapulpa, Okla.), Vol. 84, No. 102, Ed. 1 Tuesday, January 11, 2000 (open access)

Sapulpa Daily Herald (Sapulpa, Okla.), Vol. 84, No. 102, Ed. 1 Tuesday, January 11, 2000

Daily newspaper from Sapulpa, Oklahoma that includes local, state, and national news along with advertising.
Date: January 11, 2000
Creator: unknown
Object Type: Newspaper
System: The Gateway to Oklahoma History
SRS facility impacts on Crackerneck Wildlife Management Area (open access)

SRS facility impacts on Crackerneck Wildlife Management Area

Savannah River site (SRS) facilities that contain hazardous materials have completed the Emergency Preparedness Hazards Assessment (EPHA) process in accordance with Emergency Management Program Procedure (EMPP) 6Q-001. The EPHA determines the consequences of releases from these facilities and identifies events that exceed Protective Action Criteria (PAC) at defined receptor locations for areas of interest. One such area of interest is the Crackerneck wildlife Management Area (WMA). As such, facilities with releases that have the potential to exceed PAC at the Crackerneck WMA have been identified.
Date: January 11, 2000
Creator: Blanchard, A.
Object Type: Report
System: The UNT Digital Library
Stabilization of high and low solids Consolidated Incinerator Facility (CIF) waste with super cement (open access)

Stabilization of high and low solids Consolidated Incinerator Facility (CIF) waste with super cement

This report details solidification activities using selected Mixed Waste Focus Area technologies with the High and Low Solid waste streams. Ceramicrete and Super Cement technologies were chosen as the best possible replacement solidification candidates for the waste streams generated by the SRS incinerator from a list of several suggested Mixed Waste Focus Area technologies. These technologies were tested, evaluated, and compared to the current Portland cement technology being employed. Recommendation of a technology for replacement depends on waste form performance, process flexibility, process complexity, and cost of equipment and/or raw materials.
Date: January 11, 2000
Creator: Walker, B.W.
Object Type: Report
System: The UNT Digital Library
Structure of Cool Flame Fronts of Pentane, Iso-Pentane and Their Mixture (open access)

Structure of Cool Flame Fronts of Pentane, Iso-Pentane and Their Mixture

An experimental study of the combustion of two isomers of pentane, n-pentane and iso-pentane, in laminar cool flames has been carried out. Three flames were studied, one with n-pentane, the second with iso-pentane, and the third with an equimolar mixture of the two isomers. Particular attention has been given to the low temperature region ahead of the hot region of the flame and the cool flame chemistry occurring there. A unique experimental facility has been used to provide access to this cool flame region. Comparisons are made of the structures of the three flames, with particular attention on the different intermediate species produced and the correlations between the fuel molecule structure and the specific intermediates produced.
Date: January 11, 2000
Creator: Mansurov, Z A; Mironenko, A A; Bodykov, D U; Rakhimetkaliev, K N & Westbrook, C K
Object Type: Article
System: The UNT Digital Library
''Towards a High-Performance and Robust Implementation of MPI-IO on Top of GPFS'' (open access)

''Towards a High-Performance and Robust Implementation of MPI-IO on Top of GPFS''

MPI-IO/GPFS is a prototype implementation of the I/O chapter of the Message Passing Interface (MPI) 2 standard. It uses the IBM General Parallel File System (GPFS), with prototyped extensions, as the underlying file system. this paper describes the features of this prototype which support its high performance and robustness. The use of hints at the file system level and at the MPI-IO level allows tailoring the use of the file system to the application needs. Error handling in collective operations provides robust error reporting and deadlock prevention in case of returning errors.
Date: January 11, 2000
Creator: Prost, J.P.; Tremann, R.; Blackwore, R.; Hartman, C.; Hedges, R.; Jia, B. et al.
Object Type: Article
System: The UNT Digital Library