The Diesel Emission Control-Sulfur Effects (DECSE) is a joint government/industry program to determine the impact of diesel fuel sulfur levels on emission control systems whose use could lower emissions of nitrogen oxides (NO{sub x}) and particulate matter (PM) from on-highway trucks in the 2002--2004 model years. Phase 1 of the program was developed with the following objectives in mind: (1) evaluate the effects of varying the level of sulfur content in the fuel on the emission reduction performance of four emission control technologies; and (2) measure and compare the effects of up to 250 hours of aging on selected devices for multiple levels of fuel sulfur content. This interim data report summarizes results as of August, 1999, on the status of the test programs being conducted on three technologies: lean-NO{sub x} catalysts, diesel particulate filters and diesel oxidation catalysts.

Regulatory Guide 1.92 ''Combining Modal Responses and Spatial Components in Seismic Response Analysis'' was last revised in 1976. The objective of this project was to re-evaluate the current regulatory guidance for combining modal responses in response spectrum analysis, evaluate recent technical developments, and recommend revisions to the regulatory guidance. This paper describes the qualitative evaluation of modal response combination methods.

In a multiple sensor system, each sensor produces an output which is related to the desired feature according to a certain probability distribution. We propose a fuser that combines the sensor outputs to more accurately predict the desired feature. The fuser utilizes the lower envelope of regression curves of sensors to project the sensor with the least error at each point of the feature space. This fuser is optimal among all projective fusers and also satisfies the isolation property that ensures a performance at least as good as the best sensor. In the case the sensor distributions are not known, we show that a consistent estimator of this fuser can be computed entirely based on a training sample. Compared to linear fusers, the projective fusers provide a complementary performance. We propose two classes of metafusers that utilize both linear and projectives fusers to perform at least as good as the best sensor as well as the best fuser.

A NRC-BNL benchmark program for evaluation of state-of-the-art analysis methods and computer programs for seismic analysis of coupled structures with non-classical damping is described. The program includes a series of benchmarking problems designed to investigate various aspects of complexities, applications and limitations associated with methods for analysis of non-classically damped structures. Discussions are provided on the benchmarking process, benchmark structural models, and the evaluation approach, as well as benchmarking ground rules. It is expected that the findings and insights, as well as recommendations from this program will be useful in developing new acceptance criteria and providing guidance for future regulatory activities involving licensing applications of these alternate methods to coupled systems.

The overall aim of the project is to demonstrate the performance and practical use of a probe for measuring the thickness of coke deposits located within the high-temperature tubes of a thermal cracking furnace. The objective of work during this period was to enhance the sensitivity and signal-to-noise ratio of the probe measurement. Testing identified that the primary source of signal noise was traced to imperfections in the sacrificial stand-off, which was formed using a casting procedure. Laminations, voids, and impurities contained in the casting result in attenuation and dispersion of the ultrasonic signal. This report describes the work performed to optimize the signal conductance of the sacrificial stand-off.