On the stability of Poiseuille pipe flow

Numerical analysis of Poiseuille pipe flow stability using Reynolds numbe

MANAGING NUTRIENT LOSSES: SOME EMPIRICAL RESULTS ON THE POTENTIAL WATER QUALITY EFFECTS

Over-application of manure on cropland can cause water quality degradation. This paper reports a modeling approach for assessing tradeoffs among manure storage and handling systems as they relate to the nutrient loadings in cropland runoff, including nitrate losses to groundwater. The CREAMS simulation model provided estimates of nutrient losses. A linear optimization model was used to determine the income-nutrient loss tradeoffs. Six-month storage was profitable for farmers with average-size dairy herds, but compared to daily spreading caused increased nitrate leaching through the soil to groundwater resources. Twelve-month storage systems decreased farm profitability while decreasing the total nitrogen losses from farm fields.Environmental Economics and Policy,

On a Service-Oriented Approach for an Engineering Knowledge Desktop

Increasingly, manufacturing companies are shifting their focus from selling products to providing services. As a result, when designing new products, engineers must increasingly consider the life cycle costs in addition to any design requirements. To identify possible areas of concern, designers are required to consult existing maintenance information from identical products. However, in a large engineering company, the amount of information available is significant and in wide range of formats. This paper presents a prototype knowledge desktop suitable for the design engineer. The Engineering Knowledge Desktop analyses and suggests relevant information from ontologically marked-up heterogeneous web resources. It is designed using a Service-Oriented Architecture, with an ontology to mediate between Web Services. It has been delivered to the user community for evaluation

LISA Source Confusion

The Laser Interferometer Space Antenna (LISA) will detect thousands of gravitational wave sources. Many of these sources will be overlapping in the sense that their signals will have a non-zero cross-correlation. Such overlaps lead to source confusion, which adversely affects how well we can extract information about the individual sources. Here we study how source confusion impacts parameter estimation for galactic compact binaries, with emphasis on the effects of the number of overlaping sources, the time of observation, the gravitational wave frequencies of the sources, and the degree of the signal correlations. Our main findings are that the parameter resolution decays exponentially with the number of overlapping sources, and super-exponentially with the degree of cross-correlation. We also find that an extended mission lifetime is key to disentangling the source confusion as the parameter resolution for overlapping sources improves much faster than the usual square root of the observation time.Comment: 8 pages, 14 figure

Data Mining to Support Engineering Design Decision

The design and maintenance of an aero-engine generates a significant amount of documentation. When designing new engines, engineers must obtain knowledge gained from maintenance of existing engines to identify possible areas of concern. Firstly, this paper investigate the use of advanced business intelligence tenchniques to solve the problem of knowledge transfer from maintenance to design of aeroengines. Based on data availability and quality, various models were deployed. An association model was used to uncover hidden trends among parts involved in maintenance events. Classification techniques comprising of various algorithms was employed to determine severity of events. Causes of high severity events that lead to major financial loss was traced with the help of summarization techniques. Secondly this paper compares and evaluates the business intelligence approach to solve the problem of knowledge transfer with solutions available from the Semantic Web. The results obtained provide a compelling need to have data mining support on RDF/OWL-based warehoused data

Darwin Meets Einstein: LISA Data Analysis Using Genetic Algorithms

This work presents the first application of the method of Genetic Algorithms (GAs) to data analysis for the Laser Interferometer Space Antenna (LISA). In the low frequency regime of the LISA band there are expected to be tens of thousands galactic binary systems that will be emitting gravitational waves detectable by LISA. The challenge of parameter extraction of such a large number of sources in the LISA data stream requires a search method that can efficiently explore the large parameter spaces involved. As signals of many of these sources will overlap, a global search method is desired. GAs represent such a global search method for parameter extraction of multiple overlapping sources in the LISA data stream. We find that GAs are able to correctly extract source parameters for overlapping sources. Several optimizations of a basic GA are presented with results derived from applications of the GA searches to simulated LISA data.Comment: 8 pages, 12 figure

Protein misfolding induces hypoxic preconditioning via a subset of the unfolded protein response machinery

Prolonged cellular hypoxia results in energy failure and ultimately cell death. However, less-severe hypoxia can induce a cytoprotective response termed hypoxic preconditioning (HP). The unfolded protein response pathway (UPR) has been known for some time to respond to hypoxia and regulate hypoxic sensitivity; however, the role of the UPR, if any, in HP essentially has been unexplored. We have shown previously that a sublethal hypoxic exposure of the nematode Caenorhabditis elegans induces a protein chaperone component of the UPR (L. L. Anderson, X. Mao, B. A. Scott, and C. M. Crowder, Science 323:630-633, 2009). Here, we show that HP induces the UPR and that the pharmacological induction of misfolded proteins is itself sufficient to stimulate a delayed protective response to hypoxic injury that requires the UPR pathway proteins IRE-1, XBP-1, and ATF-6. HP also required IRE-1 but not XBP-1 or ATF-6; instead, GCN-2, which is known to suppress translation and induce an adaptive transcriptional response under conditions of UPR activation or amino acid deprivation, was required for HP. The phosphorylation of the translation factor eIF2α, an established mechanism of GCN-2-mediated translational suppression, was not necessary for HP. These data suggest a model where hypoxia-induced misfolded proteins trigger the activation of IRE-1, which along with GCN-2 controls an adaptive response that is essential to HP

NDM-518: EFFECTS OF NON-TRADITIONAL ISOLATOR PLACEMENT FOR SEISMIC RETROFIT

Seismic isolation delivers improved performance by means of a flexible layer at which lateral deformation is concentrated. However, for seismic retrofit applications base isolation systems can be of considerable expense, in significant part because of major alterations required at the base of the structure. The cost of introducing an additional diaphragm, constructing a seismic gap, and modifying the foundation causes the initial cost of isolation to be significantly higher than traditional non-isolation retrofit methods. To minimize initial costs, isolators may be placed directly at the top of the column level, without an additional diaphragm, instead of at the base of the building. To investigate the effects of this placement and the limits of applicability, experiments were conducted at McMaster University of a column-bearing subassembly. These experiments tested bearings on increasing flexible steel columns, investigating the effect of allowing end rotations on the bearing behaviour and the effect of large displacements on the overall stability of the beam-column system. This research looks at developing clear strength and stiffness requirements for the sub-isolation system with the aim of increasing the number of existing buildings that are candidates for retrofit with isolation