Engine Control Improvement through Application of Chaotic Time Series Analysis

The objective of this program was to investigate cyclic variations in spark-ignition (SI) engines under lean fueling conditions and to develop options to reduce emissions of nitrogen oxides (NOx) and particulate matter (PM) in compression-ignition direct-injection (CIDI) engines at high exhaust gas recirculation (EGR) rates. The CIDI activity builds upon an earlier collaboration between ORNL and Ford examining combustion instabilities in SI engines. Under the original CRADA, the principal objective was to understand the fundamental causes of combustion instability in spark-ignition engines operating with lean fueling. The results of this earlier activity demonstrated that such combustion instabilities are dominated by the effects of residual gas remaining in each cylinder from one cycle to the next. A very simple, low-order model was developed that explained the observed combustion instability as a noisy nonlinear dynamical process. The model concept lead to development of a real-time control strategy that could be employed to significantly reduce cyclic variations in real engines using existing sensors and engine control systems. This collaboration led to the issuance of a joint patent for spark-ignition engine control. After a few years, the CRADA was modified to focus more on EGR and CIDI engines. The modified CRADA examined relationships between EGR, combustion, and emissions in CIDI engines. Information from CIDI engine experiments, data analysis, and modeling were employed to identify and characterize new combustion regimes where it is possible to simultaneously achieve significant reductions in NOx and PM emissions. These results were also used to develop an on-line combustion diagnostic (virtual sensor) to make cycle-resolved combustion quality assessments for active feedback control. Extensive experiments on engines at Ford and ORNL led to the development of the virtual sensor concept that may be able to detect simultaneous reductions in NOx and PM emissions under low temperature combustion (LTC) regimes. An invention disclosure was submitted to ORNL for the virtual sensor under the CRADA. Industrial in-kind support was available throughout the project period. Review of the research results were carried out on a regular basis (annual reports and meetings) followed by suggestions for improvement in ongoing work and direction for future work. A significant portion of the industrial support was in the form of experimentation, data analysis, data exchange, and technical consultation

A genome-wide linkage analysis for reproductive traits in F2 Large White × Meishan cross gilts

Female reproductive performance traits in pigs have low heritabilities thus limiting improvement through traditional selective breeding programmes. However, there is substantial genetic variation found between pig breeds with the Chinese Meishan being one of the most prolific pig breeds known. In this study, three cohorts of Large White × Meishan F(2) cross-bred pigs were analysed to identify quantitative trait loci (QTL) with effects on reproductive traits, including ovulation rate, teat number, litter size, total born alive and prenatal survival. A total of 307 individuals were genotyped for 174 genetic markers across the genome. The genome-wide analysis of the trait-recorded F(2) gilts in their first parity/litter revealed one QTL for teat number significant at the genome level and a total of 12 QTL, which are significant at the chromosome-wide level, for: litter size (three QTL), total born alive (two QTL), ovulation rate (four QTL), prenatal survival (one QTL) and teat number (two QTL). Further support for eight of these QTL is provided by results from other studies. Four of these 12 QTL were mapped for the first time in this study: on SSC15 for ovulation rate and on SSC18 for teat number, ovulation rate and litter size

Explicit Formulas for Neumann Coefficients in the Plane-Wave Geometry

We obtain explicit formulas for the Neumann coefficients and associated quantities that appear in the three-string vertex for type IIB string theory in a plane-wave background, for any value of the mass parameter mu. The derivation involves constructing the inverse of a certain infinite-dimensional matrix, in terms of which the Neumann coefficients previously had been written only implicitly. We derive asymptotic expansions for large mu and find unexpectedly simple results, which are valid to all orders in 1/mu. Using BMN duality, these give predictions for certain gauge theory quantities to all orders in the modified 't Hooft coupling lambda'. A specific example is presented.Comment: 28 pages, 2 figures, v2: reference added, new comments and appendix, typos fixed in eqs. (86) and (89

Increased Oil Recovery From Mature Oil Fields Using Gelled Polymer Treatments

Gelled polymer treatments are applied to oil reservoirs to increase oil production and to reduce water production by altering the fluid movement within the reservoir. This report describes the results of a three-year research program aimed at reducing barriers to the widespread use of gelled polymer treatments by (1) developing methods to predict gel behavior during placement in matrix rock and fractures, (2) determining the persistence of permeability reduction after gel placement, and (3) developing methods to design production well treatments to control water production. The work focused on the gel system composed of polyacrylamide and chromium acetate. The molar mass of the polymer was about six million. Chromium(III) acetate reacted and formed crosslinks between polymer molecules. The crosslinked polymer molecules, or pre-gel aggregates, combine and grow to eventually form a 3-dimensional gel. A fundamental study to characterize the formation and growth of pre-gel aggregates was conducted. Two methods, flow field-flow fractionation (FFFF) and multi-angle laser light scattering (MALLS) were used. Studies using FFFF were inconclusive. Data taken using MALLS showed that at the gel time the average molar mass of gel aggregates increased by a factor of about three while the average size increase was approximately 50%. Increased acetate concentration in the gelant increases the gel time. The in situ performance of an added-acetate system was investigated to determine the applicability for in-depth treatments. Increased acetate concentrations delayed the development of increased flow resistance during gelant injection in short sandpacks. The development of increased flow resistance (in situ gelation) was extended from 2 to 34 days by increasing the acetate-to-chromium ratio from 38 to 153. In situ gelation occurred at a time that was approximately 22% of the bulk gelation time. When carbonate rocks are treated with gel, chromium retention in the rock may limit in-depth treatment. Chromium retention due to precipitation was investigated by flowing chromium acetate solutions through carbonate rock. Chromium precipitated faster in the rocks than in beaker experiments at similar conditions. A mathematical model previously developed fit the precipitation data reasonably well. The stability of gels when subjected to stress was investigated by experiments with gels placed in tubes and in laboratory-scale fractures. Rupture pressures for gels placed in small diameter tubes were correlated with the ratio of tube length to tube ID. In fractures, fluid leakoff from the fracture to adjacent matrix rock affected gel formation and gel stability in a positive way. Disproportionate permeability reduction (DPR) was studied in unconsolidated sandpacks and in Berea sandstone cores. A conceptual model was developed to explain the presence of DPR. The effect of a pressure gradient, imposed by injection of oil or brine, on the permeability of gel-treated cores was investigated. DPR increased significantly as the pressure gradient was decreased. The magnitude of the pressure gradient had a much larger effect on water permeability than on oil permeability

Linking bone development on the caudal aspect of the distal phalanx with lameness during life

Claw horn disruption lesions (CHDL; sole hemorrhage, sole ulcer, and white line disease) cause a large proportion of lameness in dairy cattle, yet their etiopathogenesis remains poorly understood. Untreated CHDL may be associated with damage to the internal anatomy of the foot, including to the caudal aspect of the distal phalanx upon which bone developments have been reported with age and with sole ulcers at slaughter. The primary aim of this study was to assess whether bone development was associated with poor locomotion and occurrence of CHDL during a cow’s life. A retrospective cohort study imaged 282 hind claws from 72 Holstein-Friesian dairy cows culled from a research herd using X-ray micro–computed tomography (μ-CT; resolution: 0.11 mm). Four measures of bone development were taken from the caudal aspect of each distal phalanx, in caudal, ventral, and dorsal directions, and combined within each claw. Cow-level variables were constructed to quantify the average bone development on all hind feet (BD-Ave) and bone development on the most severely affected claw (BD-Max). Weekly locomotion scores (1–5 scale) were available from first calving. The variables BD-Ave and BD-Max were used as outcomes in linear regression models; the explanatory variables included locomotion score during life, age, binary variables denoting lifetime occurrence of CHDL and of infectious causes of lameness, and other cow variables. Both BD-Max and BD-Ave increased with age, CHDL occurrence, and an increasing proportion of locomotion scores at which a cow was lame (score 4 or 5). The models estimated that BD-Max would be 9.8 mm (SE 3.9) greater in cows that had been lame at >50% of scores within the 12 mo before slaughter (compared with cows that had been assigned no lame scores during the same period), or 7.0 mm (SE 2.2) greater if the cow had been treated for a CHDL during life (compared with cows that had not). Additionally, histology demonstrated that new bone development was osteoma, also termed “exostosis.” Age explained much of the variation in bone development. The association between bone development and locomotion score during life is a novel finding, and bone development appears specific to CHDL. Bone development on the most severely affected foot was the best explained outcome and would seem most likely to influence locomotion score. To stop irreparable anatomical damage within the foot, early identification of CHDL and effective treatment could be critical

Divergence Cancellation and Loop Corrections in String Field Theory on a Plane Wave Background

We investigate the one-loop energy shift E to certain two-impurity string states in light-cone string field theory on a plane wave background. We find that there exist logarithmic divergences in the sums over intermediate mode numbers which cancel between the cubic Hamiltonian and quartic ``contact term''. Analyzing the impurity non-conserving channel we find that the non-perturbative, order g_2^2 sqrt(lambda') contribution to E/mu predicted in hep-th/0211220 is in fact an artifact of these logarithmic divergences and vanishes with them, leaving an order g_2^2 lambda' contribution. Exploiting the supersymmetry algebra, we present a form for the energy shift which appears to be manifestly convergent and free of non-perturbative terms. We use this form to argue that E/mu receives order g_2^2 lambda' contributions at every order in intermediate state impurities.Comment: 27 pages; added references, acknowledgments, missing normalization in equations 2.3 - 2.8, also cleaned up notation, and added a few footnote

Space/Time Noncommutativity in String Theories without Background Electric Field

The appearance of space/time non-commutativity in theories of open strings with a constant non-diagonal background metric is considered. We show that, even if the space-time coordinates commute, when there is a metric with a time-space component, no electric field and the boundary condition along the spatial direction is Dirichlet, a Moyal phase still arises in products of vertex operators. The theory is in fact dual to the non-commutatitive open string (NCOS) theory. The correct definition of the vertex operators for this theory is provided. We study the system also in the presence of a $B$ field. We consider the case in which the Dirichlet spatial direction is compactified and analyze the effect of these background on the closed string spectrum. We then heat up the system. We find that the Hagedorn temperature depends in a non-extensive way on the parameters of the background and it is the same for the closed and the open string sectors.Comment: 18 pages, JHEP styl

Supergravity Null Scissors and Super-Crosses

In this paper we construct the supergravity solutions for the orthogonally intersecting null scissors and the fluxed D-strings. We name the latter as the super-crosses according to their shape. It turns out that the smeared solutions are U-dual related to the intersecting $(p,q)$-strings. Their open string properties are also studied. As a by-product, we clarify the supersymmetry conditions of D2-D2 pairs with most generic fluxes.Comment: 16 pages, 1 figure;v2. minor comment revised;v3. references added, final to JHE