32 research outputs found

    In -cylinder combustion -based virtual emissions sensing

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    The development of a real-time, on-board measurement of exhaust emissions from heavy-duty engines would offer tremendous advantages in on-board diagnostics and engine control. In the absence of suitable measurement hardware, an alternative approach is the development of software-based predictive approaches. This study demonstrates the feasibility of using in-cylinder pressure-based variables as the inputs to predictive neural networks that are then used to predict engine-out exhaust gas emissions. Specifically, a large steady-state engine operation data matrix provides the necessary information for training a successful predictive network while at the same time eliminating errors produced by the dispersive and time-delay effects of the emissions measurement system which includes the exhaust system, the dilution tunnel, and the emissions analyzers. The steady-state training conditions allow for the correlation of time-averaged in-cylinder combustion variables to the engine-out gaseous emissions. A back-propagation neural network is then capable of learning the relationships between these variables and the measured gaseous emissions with the ability to interpolate between steady-state points in the matrix. The networks were then validated using the transient Federal Test Procedure cycle and in-cylinder combustion parameters gathered in real time through the use of an acquisition system based on a digital signal processor. The predictive networks for NOx and CO 2 proved highly successful while those for HC and CO were not as effective. Problems with the HC and CO networks included very low measured levels and validation data that fell beyond the training matrix boundary during transient engine operation

    NASA advanced design program: Analysis, design, and construction of a solar powered aircraft

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    Increase in energy demands coupled with rapid depletion of natural energy resources have deemed solar energy as the most logical alternative source of power. The major objective of this project was to build a solar powered remotely controlled aircraft to demonstrate the feasibility of solar energy as an effective, alternate source of power. The final design was optimized for minimum weight and maximum strength of the structure. These design constraints necessitated a carbon fiber composite structure. Surya is a lightweight, durable aircraft capable of achieving level flight powered entirely by solar cells

    Solar Powered Multipurpose Remotely Powered Aircraft

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    Increase in energy demands coupled with rapid depletion of natural energy resources have deemed solar energy as an attractive alternative source of power. The focus was to design and construct a solar powered, remotely piloted vehicle to demonstrate the feasibility of solar energy as an effective, alternate source of power. The final design included minimizing the power requirements and maximizing the strength-to-weight and lift-to-drag ratios. Given the design constraints, Surya (the code-name given to the aircraft), is a lightweight aircraft primarily built using composite materials and capable of achieving level flight powered entirely by solar energy

    The dopamine β-hydroxylase -1021C/T polymorphism is associated with the risk of Alzheimer's disease in the Epistasis Project

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    Contains fulltext : 88930.pdf (publisher's version ) (Open Access)BACKGROUND: The loss of noradrenergic neurones of the locus coeruleus is a major feature of Alzheimer's disease (AD). Dopamine beta-hydroxylase (DBH) catalyses the conversion of dopamine to noradrenaline. Interactions have been reported between the low-activity -1021T allele (rs1611115) of DBH and polymorphisms of the pro-inflammatory cytokine genes, IL1A and IL6, contributing to the risk of AD. We therefore examined the associations with AD of the DBH -1021T allele and of the above interactions in the Epistasis Project, with 1757 cases of AD and 6294 elderly controls. METHODS: We genotyped eight single nucleotide polymorphisms (SNPs) in the three genes, DBH, IL1A and IL6. We used logistic regression models and synergy factor analysis to examine potential interactions and associations with AD. RESULTS: We found that the presence of the -1021T allele was associated with AD: odds ratio = 1.2 (95% confidence interval: 1.06-1.4, p = 0.005). This association was nearly restricted to men < 75 years old: odds ratio = 2.2 (1.4-3.3, 0.0004). We also found an interaction between the presence of DBH -1021T and the -889TT genotype (rs1800587) of IL1A: synergy factor = 1.9 (1.2-3.1, 0.005). All these results were consistent between North Europe and North Spain. CONCLUSIONS: Extensive, previous evidence (reviewed here) indicates an important role for noradrenaline in the control of inflammation in the brain. Thus, the -1021T allele with presumed low activity may be associated with misregulation of inflammation, which could contribute to the onset of AD. We suggest that such misregulation is the predominant mechanism of the association we report here

    Relative importance of population size, fishing pressure and temperature on the spatial distribution of nine Northwest Atlantic groundfish stocks

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    <div><p>The spatial distribution of nine Northwest Atlantic groundfish stocks was documented using spatial indicators based on Northeast Fisheries Science Center spring and fall bottom trawl survey data, 1963–2016. We then evaluated the relative importance of population size, fishing pressure and bottom temperature on spatial distribution with an information theoretic approach. Northward movement in the spring was generally consistent with prior analyses, whereas changes in depth distribution and area occupancy were not. Only two stocks exhibited the same changes in spatiotemporal distribution in the fall as compared with the spring. Fishing pressure was the most important predictor of the center of gravity (i.e., bivariate mean location of the population) for the majority of stocks in the spring, whereas in the fall this was restricted to the east-west component. Fishing pressure was also the most important predictor of the dispersion around the center of gravity in both spring and fall. In contrast, biomass was the most important predictor of area occupancy for the majority of stocks in both seasons. The relative importance of bottom temperature was ranked highest in the fewest number of cases. This study shows that fishing pressure, in addition to the previously established role of climate, influences the spatial distribution of groundfish in the Northwest Atlantic. More broadly, this study is one of a small but growing body of literature to demonstrate that fishing pressure has an effect on the spatial distribution of marine resources. Future work must consider both fishing pressure and climate when examining mechanisms underlying fish distribution shifts.</p></div

    Northeast Fisheries Science Center bottom trawl survey offshore strata.

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    <p>Stock strata definitions are shown for Gulf of Maine and Georges Bank cod (upper left), the northern and southern stocks of red hake and silver hake (upper right), Georges Bank and (spring only) Southern New England-Mid Atlantic yellowtail flounder (lower left). Ecoregions used in previous analyses are also shown (lower right). Further details, as well as the stock strata definition for white hake, are provided in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0196583#pone.0196583.s001" target="_blank">S1 Supporting Information</a>.</p

    A Statewide Quality Improvement Collaborative\u27s Adherence to the 2017 American Urological Association Guidelines Regarding Initial Evaluation of Patients With Clinical T1 Renal Masses

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    OBJECTIVE: To evaluate MUSIC-KIDNEY\u27s adherence to the American Urological Association (AUA) guidelines regarding the initial evaluation of patient\u27s with clinical T1 (cT1) renal masses. METHODS: We reviewed MUSIC-KIDNEY registry data for patients with newly diagnosed cT1 renal masses to assess for adherence with the 2017 AUA guideline statements regarding recommendations to obtain (1) CMP, (2) CBC, (3) UA, (4) abdominal cross-sectional imaging, and (5) chest imaging. An evaluation consisting of all 5 guideline measures was considered complete compliance. Variation with guideline adherence was assessed by contributing practice, management strategy, and renal mass size. RESULTS: We identified 1808 patients with cT1 renal masses in the MUSIC-KIDNEY registry, of which 30% met the definition of complete compliance. Most patients received care that was compliant with recommendations to obtain laboratory testing with 1448 (80%), 1545 (85%), and 1472 (81%) patients obtaining a CMP, CBC, and UA respectively. Only 862 (48%) patients underwent chest imaging. Significant variation exists in complete guideline compliance for contributing practices, ranging from 0% to 45% as well as for patients which underwent immediate intervention compared with initial observation (37% vs 23%) and patients with cT1b masses compared with cT1a masses (36% vs 28%). CONCLUSION: Complete guideline compliance in the initial evaluation of patients with cT1 renal masses is poor, which is mainly driven by omission of chest imaging. Significant variation in guideline adherence is seen across practices, as well as patients undergoing an intervention vs observation, and cT1a vs cT1b masses. There are ample quality improvement opportunities to increase adherence and decrease variability with guideline recommendations

    Proportion of stocks for which a variable was the most important predictor, by spatial indicator.

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    <p>Spatial indicators and associated units are: geographically referenced longitude and latitude of the center of gravity (XCG and YCG, respectively; km), inertia (km<sup>2</sup>), depth (m) and positive area (PA; km<sup>2</sup>). Predictor variables are: Northeast Fisheries Science Center (NEFSC) bottom trawl survey stratified mean kg per tow (biomass; kg), catch/NEFSC stratified mean kg per tow (relative <i>F</i>) and NEFSC stratified mean bottom temperature (°C). Proportions may not sum to one in the case of ties.</p
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