Compensators: The Coefficient Wordlength Issue

Absbulci--'Ibere exist a mrmber of maulematid procedures for des&ing rllscrete-thne compensators. However, the digital implementatroo of these designs, with a micropmassor, for example, bas not received nearly as thorough an investigation. 'Ihe finite-precision natnre of the digital hardware makes it necessary to choose a computational stroeture that wil performadequafelywithregardtotheinitialobjeetivesofthedeslgaThls paper desuii a procedure for estimating the reqnired fixed-point wefficient wordlength for any given computational structure for the implementation of a singleinput single-ontpnt LQG design. 'Ihe dts are compared to the actnal number of bits necssary to d eve a specified perfomance index. design and the implementation phases may not be totally I

21st Century Locomotive Technology: Quarterly Technical Status Report 6 DOE/AL68284-TSR06

Experimental work to map the performance of the High Pressure Common Rail (HPCR) system on a locomotive is in progress. The experimental trends agree with KIVA modeling predictions. Injection optimization is in progress. Electrically-assisted turbocharger modeling was used to study passenger locomotive performance improvements. Energy storage cycling life testing began, and an improved battery state algorithm was determined. The hybrid locomotive energy storage was prepared for energy management system algorithm testing. Progress in reliable methods for computing optimal driving plans, and methods to reduce the complexity of the necessary optimization are reported

Bifurcation Analysis of Surge and Rotating Stall in Axial Flow Compressors

In this paper, the surge and rotating stall post instability behaviors of anial flow compressors are investigated from a bifurcation-theoretic perspective. A sequence of local and global bifurcations of the nonlinear system dynamics is uncovered. This includes a previously unknown global bifurcation of a pair of large amplitude periodic solutions. Resulting from this bifurcation are a stable oscillation ("surge") and an unstable oscillation ("antisurge"). The latter oscillation is found to have a deciding significance regarding post-instability behavior experienced by the compressor. These results are used to reconstruct Greitzer's (1976) findings regarding the manner in which post-instability behavior depends on system parameters. Moreover, the results provide significant new insight deemed valuable in the prediction, analysis and control of stall instabilities in gas turbine jet engines

Novel rpsK / rpsD primer-probe assay improves detection of Campylobacter jejuni and Campylobacter coli in human stool

Campylobacter causes bacterial enteritis, dysentery, and growth faltering in children in low- and middle-income countries (LMICs). Campylobacter spp. are fastidious organisms, and their detection often relies on culture independent diagnostic technologies, especially in LMICs. Campylobacter jejuni and Campylobacter coli are most often the infectious agents and in high income settings together account for 95% of Campylobacter infections. Several other Campylobacter species have been detected in LMIC children at an increased prevalence relative to high income settings. After doing extensive whole genome sequencing of isolates of C. jejuni and C. coli in Peru, we observed heterogeneity in the binding sites for the main species-specific PCR assay (cadF) and designed an alternative rpsKD-based qPCR assay to detect both C. jejuni and C. coli. The rpsKD-based qPCR assay identified 23% more C.jejuni/ C.coli samples than the cadF assay among 47 Campylobacter genus positive cadF negative samples verified to have C. jejuni and or C. coli with shotgun metagenomics. This assay can be expected to be useful in diagnostic studies of enteric infectious diseases and be useful in revising the attribution estimates of Campylobacter in LMICs

Number of reads detected for <i>Campylobacter jejuni</i>, <i>C</i>. <i>coli</i>, <i>C</i>. <i>upsaliensis</i>, and <i>C</i>. <i>helveticus</i>, <i>C</i>. <i>concisus</i> and <i>C</i>. <i>infans</i> in human fecal samples, and qPCR status.

Samples highlighted in green show highlight 8 of 11 samples that were negative using cadF primers, positive with new rpsK/rpsD primers, and confirmed as having C jejuni or C. coli infection by metagenomic analysis.</p

Primer and probes used to detect <i>Campylobacter</i> spp. and <i>Campylobacter jejuni</i> / <i>Campylobacter coli</i>.

Primer and probes used to detect Campylobacter spp. and Campylobacter jejuni / Campylobacter coli.</p

Contingency Tables of <i>Campylobacter</i> spp (16S rRNA), and <i>Campylobacter jejuni</i>/ <i>Campylobacter coli</i> using the cadF primer probe set and the <i>rpsK/rpsD</i> primer probe set.

Using the cadF primers, 66% (31/47) Campylobacter infections would be assigned to “other Campylobacter” whereas only 41.3% (19/46) Campylobacter infections would be assigned to this category using newly designed rpsK/rpsD primer set. No specimens that were cadF positive were negative using rpsK/rpsD primers.</p