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in creator/contributor: "Smith, J.R."

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Exotic Physics: Search for New Physics Leading to High Mass Tau Pairs With ppbar Collisions at 1.96 TeV Using Cdf Ii

Abstract: We present the results of a search for anomalous resonant production of tau lepton pairs with large invariant mass, the first such search using the CDF II Detector in Run II of the Tevatron p{bar p} collider. Such anomalous production could arise from various new physics processes. In a data sample corresponding to 195 pb{sup -1} of integrated luminosity we predict 2.8 {+-} 0.5 events from Standard Model background processes and observe 4. We use this result to set limits on the produ… more

Date: June 15, 2005

Creator: Academia Sinica Institute of Physics

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

A Sequential Fluid-mechanic Chemical-kinetic Model of Propane HCCI Combustion

We have developed a methodology for predicting combustion and emissions in a Homogeneous Charge Compression Ignition (HCCI) Engine. This methodology combines a detailed fluid mechanics code with a detailed chemical kinetics code. Instead of directly linking the two codes, which would require an extremely long computational time, the methodology consists of first running the fluid mechanics code to obtain temperature profiles as a function of time. These temperature profiles are then used as inp… more

Date: November 29, 2000

Creator: Aceves, S M; Flowers, D L; Martinez-Frias, J; Smith, J R; Westbrook, C; Pitz, W et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

A desiccant dehumidifier for electric vehicle heating

Vehicle heating requires a substantial amount of energy. Engines in conventional cars produce enough waste heat to provide comfort heating and defogging/defrosting, even under very extreme conditions. Electric vehicles (EVs), however, generate little waste heat. Using battery energy for heating may consume a substantial fraction of the energy storage capacity, reducing the vehicle range, which is one of the most important parameters in determining EV acceptability. Water vapor generated by the … more

Date: September 1996

Creator: Aceves, S. M. & Smith, J. R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Hybrid and conventional hydrogen engine vehicles that meet EZEV emissions

In this paper, a time-dependent engine model is used for predicting hydrogen engine efficiency and emissions. The model uses basic thermodynamic equations for the compression and expansion processes, along with an empirical correlation for heat transfer, to predict engine indicated efficiency. A friction correlation and a supercharger/turbocharger model are then used to calculate brake thermal efficiency. The model is validated with many experimental points obtained in a recent evaluation of a … more

Date: December 10, 1996

Creator: Aceves, S. M. & Smith, J. R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

A hybrid vehicle evaluation code and its application to vehicle design

This report describes a hybrid vehicle simulation model, which can be applied to many of the vehicles currently being considered for low pollution and high fuel economy. The code operates interactively, with all the vehicle information stored in data files. The code calculates fuel economy for three driving schedules, time for 0-96 km/h at maximum acceleration, hill climbing performance, power train dimensions, and pollution generation rates. This report also documents the application of the co… more

Date: July 15, 1994

Creator: Aceves, S. M. & Smith, J. R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

A hybrid vehicle evaluation code and its application to vehicle design. Revision 1

This paper describes a hybrid vehicle simulation model which can be applied to many of the vehicles currently being considered for low pollution and high fuel economy. The code operates in batch mode with all the vehicle information stored in data files. The code calculates fuel economy for three driving schedules, time for 0--96 km/h at maximum acceleration, hill climbing performance, power train dimensions, and pollution generation rates. This paper also documents the application of the code … more

Date: September 15, 1994

Creator: Aceves, S. M. & Smith, J. R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

A hybrid vehicle evaluation code and its application to vehicle design. Revision 2

This paper describes a hybrid vehicle simulation model which can be applied to many of the vehicles currently being considered for low pollution and high fuel economy. The code operates in batch mode with all the vehicle information stored in data files. The code calculates power train dimensions, fuel economy for three driving schedules, time for 0-96 km/h at maximum acceleration, hill climbing performance, and pollution generation rates. This paper also documents the application of the code t… more

Date: December 13, 1994

Creator: Aceves, S. M. & Smith, J. R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Lean-burn hydrogen spark-ignited engines: the mechanical equivalent to the fuel cell

Fuel cells are considered as the ideal power source for future vehicles, due to their high efficiency and low emissions. However, extensive use of fuel cells in light-duty vehicles is likely to be years away, due to their high manufacturing cost. Hydrogen-fueled, spark-ignited, homogeneous-charge engines offer a near-term alternative to fuel cells. Hydrogen in a spark-ignited engine can be burned at very low equivalence ratios, so that NO[sub x] emissions can be reduced to less than 10 ppm with… more

Date: October 1, 1996

Creator: Aceves, S. M. & Smith, J. R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Optimum flywheel sizing for parallel and series hybrid vehicles

Flywheels have the possibility of providing high turnaround efficiency and high specific power output. These characteristics are very important for the successful manufacture of parallel and series hybrid vehicles, which have the potential for providing high fuel economy and very low emissions with range and performance comparable to today`s light-duty vehicles. Flywheels have a high specific power output, but relatively low specific energy output. Therefore, it is of importance to determine en… more

Date: December 20, 1996

Creator: Aceves, S. M. & Smith, J. R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

HCCl Combustion: Analysis and Experiments

Homogeneous charge compression ignition (HCCI) is a new combustion technology that may develop as an alternative to diesel engines with high efficiency and low NOx and particulate matter emissions. This paper describes the HCCI research activities being currently pursued at Lawrence Livermore National Laboratory and at the University of California Berkeley. Current activities include analysis as well as experimental work. On analysis, we have developed two powerful tools: a single zone model an… more

Date: May 4, 2001

Creator: Aceves, S. M.; Flowers, D. L.; Martinez-Frias, J.; Smith, J. R.; Dibble, R.; Au, M. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

A Computer Generated Reduced Iso-Octane Chemical Kinetic Mechanism Applied to Simulation of HCCI Combustion

This paper shows how a computer can systematically remove non-essential chemical reactions from a large chemical kinetic mechanism. The computer removes the reactions based upon a single solution using a detailed mechanism. The resulting reduced chemical mechanism produces similar numerical predictions significantly faster than predictions that use the detailed mechanism. Specifically, a reduced chemical kinetics mechanism for iso-octane has been derived from a detailed mechanism by eliminating… more

Date: August 12, 2002

Creator: Aceves, S. M.; Martinez-Frias, J.; Flowers, D.; Smith, J. R.; Dibble, R. & Chen, J. Y.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Compression ratio effect on methane HCCI combustion

We have used the HCT (Hydrodynamics, Chemistry and Transport) chemical kinetics code to simulate HCCI (homogeneous charge compression ignition) combustion of methane-air mixtures. HCT is applied to explore the ignition timing, bum duration, NO<sub>x</sub> production, gross indicated efficiency and gross IMEP of a supercharged engine (3 atm. Intake pressure) with 14:1, 16:l and 18:1 compression ratios at 1200 rpm. HCT has been modified to incorporate the effect of heat transfer and to calculate … more

Date: September 29, 1998

Creator: Aceves, S. M.; Pitz, W.; Smith, J. R. & Westbrook, C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Computer modeling in the design and evaluation of electric and hybrid vehicles

This demonstration project uses modern simulation techniques to illustrate the important technologies and design variables that an auto-designer would consider in production a high efficiency, low emissions vehicle. Simulation and modeling techniques use the idea of capturing the relationships between real components of the systems with mathematical equations. These equations are then solved on a computer to simulate the behavior or performance of the system under various conditions. In the cur… more

Date: August 16, 1996

Creator: Aceves, S. M.; Smith, J. R. & Johnson, N. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Optimization of a CNG series hybrid concept vehicle

Compressed Natural Gas (CNG) has favorable characteristics as a vehicular fuel, in terms of fuel economy as well as emissions. Using CNG as a fuel in a series hybrid vehicle has the potential of resulting in very high fuel economy (between 26 and 30 km/liter, 60 to 70 mpg) and very low emissions (substantially lower than Federal Tier II or CARB ULEV). This paper uses a vehicle evaluation code and an optimizer to find a set of vehicle parameters that result in optimum vehicle fuel economy. The v… more

Date: September 22, 1995

Creator: Aceves, S. M.; Smith, J. R.; Perkins, L. J.; Haney, S. W. & Flowers, D. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Sensitivity of natural gas HCCI combustion to fuel and operating parameters using detailed kinetic modeling

This paper uses the HCT (Hydrodynamics, Chemistry and Transport) chemical kinetics code to analyze natural gas HCCI combustion in an engine. The HCT code has been modified to better represent the conditions existing inside an engine, including a wall heat transfer correlation. Combustion control and low power output per displacement remain as two of the biggest challenges to obtaining satisfactory performance out of an HCCI engine, and these are addressed in this paper. The paper considers the … more

Date: July 19, 1999

Creator: Aceves, S.; Dibble, R.; Flowers, D.; Smith, J. R. & Westbrook, C. K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Sensitivity of Satellite-Retrieved Cloud Properties to the Effective Variance of Cloud Droplet Size Distribution

Cloud reflectance models currently used in cloud property retrievals from satellites have been developed using size distributions defined by a set of fixed effective radii with a fixed effective variance. The satellite retrievals used for the Atmospheric Radiation Measurement (ARM) program assume droplet size distributions with an effective variance value of 0.10 (Minnis et al. 1998); the International Satellite Cloud Climatology Project uses 0.15 (Rossow and Schiffer 1999); and the Moderate Re… more

Date: March 18, 2005

Creator: Arduini, R. F.; Minnis, P.; Smith, Jr., W. L.; Ayers, J. K.; Khaiyer, M. M. & Heck, P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Integrated technical and economic assessments of transport and storage of hydrogen

Transportation will be a major market for hydrogen because of its great size and the value of energy at the wheels of a vehicle in comparison to its heating value. Hydrogen also offers important potential efficiency gains over hydrocarbon fuels. However, hydrogen end-use technologies will not develop without a reliable hydrogen supply infrastructure. By the same token, reliable infrastructures will not develop without end-use demand. Our task is to analyze the costs of various infrastructure op… more

Date: April 1, 1994

Creator: Berry, G. D. & Smith, J. R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

A smooth transition to hydrogen transportation fuel

The goal of this work is to examine viable near-term infrastructure options for a transition to hydrogen fueled vehicles and to suggest profitable directions for technology development. The authors have focused in particular on the contrasting options of decentralized production using the existing energy distribution network, and centralized production of hydrogen with a large-scale infrastructure. Delivered costs have been estimated using best available industry cost and deliberately conservat… more

Date: April 14, 1995

Creator: Berry, G. D.; Smith, J. R. & Schock, R. N.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Observation of reflected waves on the SABRE positive polarity inductive adder MITL

We are studying the coupling of extraction applied-B ion diodes to Magnetically Insulated Transmission Line (MITLs) on the SABRE (Sandia Accelerator and Beam Research Experiment, 6 MV, 300 kA) positive polarity inductive voltage adder. Our goal is to determine conditions under which efficient coupling occurs. The best total power efficiency for an ideal ion diode load (i.e., without parasitic losses) is obtained by maximizing the product of cathode current and gap voltage. MITLs require that th… more

Date: August 1, 1993

Creator: Cuneo, M. E.; Poukey, J. W.; Mendel, C. W.; Rosenthal, S. E.; Hanson, D. L.; Smith, J. R. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Composition of Shale-Oil Naphtha

From Summary: "This report describes the analysis if shale-oil naphthas and discusses their composition, based on investigation by the Federal Bureau of Mines. Individual compounds identified in this investigation. are listed, together with those reported previously in the literature. Also, quantitative data are given on the occurrence of individual compounds and groups of related compounds."

Date: 1961

Creator: Dinneen, G. U.; Van Meter, R. A.; Smith, J. R.; Bailey, C. W.; Cook, G. L.; Allbright, C. S. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Operation of a Four-Cylinder 1.9L Propane Fueled HCCI Engine

A four-cylinder 1.9 Volkswagen TDI Engine has been converted to run in Homogeneous Charge Compression Ignition (HCCI) mode. The stock configuration is a turbocharged direct injection Diesel engine. The combustion chamber has been modified by discarding the in-cylinder Diesel fuel injectors and replacing them with blank inserts (which contain pressure transducers). The stock pistons contain a reentrant bowl and have been retained for the tests reported here. The intake and exhaust manifolds have… more

Date: March 15, 2001

Creator: Flowers, D.; Aceves, S. M.; Martinez-Frias, J.; Smith, J. R.; Au, M.; Girard, J. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Operation of a Four-Cylinder 1.9L Propane Fueled Homogeneous Charge Compression Ignition Engine: Basic Operating Characteristics and Cylinder-to-Cylinder Effects

Date: March 12, 2001

Creator: Flowers, D.; Aceves, S. M.; Martinez-Frias, J.; Smith, J. R.; Au, M.; Girard, J. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Draft versus finished sequence data for DNA and protein diagnostic signature development

Sequencing pathogen genomes is costly, demanding careful allocation of limited sequencing resources. We built a computational Sequencing Analysis Pipeline (SAP) to guide decisions regarding the amount of genomic sequencing necessary to develop high-quality diagnostic DNA and protein signatures. SAP uses simulations to estimate the number of target genomes and close phylogenetic relatives (near neighbors, or NNs) to sequence. We use SAP to assess whether draft data is sufficient or finished sequ… more

Date: October 29, 2004

Creator: Gardner, S N; Lam, M W; Smith, J R; Torres, C L & Slezak, T R

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Sequencing Needs for Viral Diagnostics

We built a system to guide decisions regarding the amount of genomic sequencing required to develop diagnostic DNA signatures, which are short sequences that are sufficient to uniquely identify a viral species. We used our existing DNA diagnostic signature prediction pipeline, which selects regions of a target species genome that are conserved among strains of the target (for reliability, to prevent false negatives) and unique relative to other species (for specificity, to avoid false positives… more

Date: January 26, 2004

Creator: Gardner, S N; Lam, M; Mulakken, N J; Torres, C L; Smith, J R & Slezak, T

Item Type: Article

Partner: UNT Libraries Government Documents Department