292 research outputs found

    Aeration System Design for Flat Grain Storages with an Expert System

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    An expert system, Aeration System Design (ASD), was developed for the design of aeration systems for farm-sized flat grain storages. ASD requests information about the storage problem from a user and generates a custom design drawing, component specification list, and management recommendations. The knowledge base was derived from publications and experts. ASD represents the first attempt to consolidate aeration system design guidelines and procedures for flat grain storage into an expert system. ASD uses illustrations to communicate concepts and terminology more clearly with users. A feature of ASD allows an expert to change the design guidelines and factors. For example, alternative methods of determining the layout and length of ducts can be selected. ASD offers the capability of rapidly designing an aeration system and changing design guidelines to study the effects upon the design

    SITE-SPECIFIC VERSUS WHOLE-FIELD FERTILITY AND LIME MANAGEMENT IN MICHIGAN SOYBEANS AND CORN

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    Prior research into variable-rate application (VRA) of fertilizer nutrients has found profitability to be lacking in single nutrient applications to U.S. cereal crops. This study examines the yield and cost effects of VRA phosphorus, potassium and lime application on Michigan corn and soybean farm fields in 1998-2001. After four years, we found no yield gain from site-specific management, but statistically significant added costs, resulting in no gain in profitability. Contrary to results elsewhere, there was no evidence of enhanced spatial yield stability due to site-specific fertility management. Likewise, there was no evidence of decreased variability of phosphorus, potassium or lime after VRA treatment. Site-specific response functions and yield goals might also enhance the likelihood of profitable VRA in the future.Crop Production/Industries,

    Evaluating a Computer Program with a Structured Expert Review Process

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    A structured expert review process was implemented to evaluate the technical content and usability of a program on aeration system design for grain storages. Technical evaluation was used to determine if the computer program generated solutions similar to expert solutions. Other aspects of the evaluation focused on measures of ease of use, effectiveness of information conveyance and usefulness of solution. The evaluation procedure and questionnaires are described and results from the evaluation of an aeration system design program are summarized. The evaluation process served to validate the aeration system design program, generate suggestions for improving the program, identify areas for further research and advance aeration system design technology by bringing together experts representing the range of practice. The review process was beneficial and could be adapted for use with other decision support programs

    A Further Look at Potential Impact of Satlets on Design, Production, and Cost of Satellite Systems

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    For the past 50 years, the morphology for satellites has remained fundamentally unchanged despite evolutions in manufacturing, communications, and software occurring in other industries. Primary spacecraft support systems—power, attitude control, and others—are designed in the same way, whether in space telescopes, large communications satellites, interplanetary spacecraft, or Cubesats. This paradigm has been the status quo in spacecraft design and construction and has precluded any industry-wide, large-scale cost savings while maintaining performance. To change this trend and ensure performance and utility at low cost, that can scale, DARPA postulated the concept of a cellularized satellite, or “satlet,” as a satellite architectural unit. In this new morphology, each satlet would provide some fraction of the overall functions that, when aggregated via hardware and software, provide spacecraft space system with its complete required capabilities. The DARPA Phoenix program has developed this satlet morphology in Phase I and plans to validate and demonstrate it in a series of steps that exercise various applications and levels of configuration flexibility enabled by a satlet architecture. The first system experiment is planned to be conducted on orbit in 2015. This paper aims to take a deeper look at the potential impact of space systems with cellular based designs, and using historical data showcases how design, production and ultimately cost can form the foundation for next generation spacecraft opportunities. A first order analysis conducted in a previous paper indicated that U.S.-launched satellites alone could create a market demand for 2,000-8,000 satlets flown per year, while the overall annual world satellite market could create demand for 10,000-40,000 satlets. This paper explores the instantiation of a cellular morphology to design, production and development to further quantify the impact of this revolutionary space system capability

    Beam tests of a large-scale TORCH time-of-flight demonstrator

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    The TORCH time-of-flight detector is designed to provide particle identification in the momentum range 2-10 GeV/c over large areas. The detector exploits prompt Cherenkov light produced by charged particles traversing a 10 mm thick quartz plate. The photons propagate via total internal reflection and are focused onto a detector plane comprising position-sensitive Micro-Channel Plate Photo-Multiplier Tubes (MCP-PMT) detectors. The goal is to achieve a single-photon timing resolution of 70 ps, giving a timing precision of 15 ps per charged particle by combining the information from around 30 detected photons. The MCP-PMT detectors have been developed with a commercial partner (Photek Ltd, UK), leading to the delivery of a square tube of active area 53 ×\times 53mm2^2 with a granularity of 8 ×\times 128 pixels equivalent. A large-scale demonstrator of TORCH, having a quartz plate of dimensions 660 ×\times 1250 ×\times 10 mm3^3 and read out by a pair of MCP-PMTs with custom readout electronics, has been verified in a test beam campaign at the CERN PS. Preliminary results indicate that the required performance is close to being achieved. The anticipated performance of a full-scale TORCH detector at the LHCb experiment is presented.Comment: 12 pages, 7 figures, Paper submitted to Nuclear Instruments & Methods in Physics Research, Section A - Special Issue VCI 201

    Status of the TORCH time-of-flight project

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    TORCH is a time-of-flight detector, designed to provide charged pi/K particle identification up to a momentum of 10 GeV/c for a 10 m flight path. To achieve this level of performance, a time resolution of 15 ps per incident particle is required. TORCH uses a plane of quartz of 1 cm thickness as a source of Cherenkov photons, which are then focussed onto square Micro-Channel Plate Photomultipliers (MCP-PMTs) of active area 53 x 53 mm^2, segmented into 8 x 128 pixels equivalent. A small-scale TORCH demonstrator with a customised MCP-PMT and associated readout electronics has been successfully operated in a 5 GeV/c mixed pion/proton beam at the CERN PS facility. Preliminary results indicate that a single-photon resolution better than 100 ps can be achieved. The expected performance of a full-scale TORCH detector for the Upgrade II of the LHCb experiment is also discussed.Comment: 9 pages, 6 figures, Paper submitted to Nuclear and Methods A : Proceedings of the 10th International Workshop on Ring Imaging Cherenkov Detectors (RICH 2018), Moscow, Russia, July 29 to August 4 201

    Implementable Deep Learning for Multi-sequence Proton MRI Lung Segmentation:A Multi-center, Multi-vendor, and Multi-disease Study

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    Background: Recently, deep learning via convolutional neural networks (CNNs) has largely superseded conventional methods for proton (1H)-MRI lung segmentation. However, previous deep learning studies have utilized single-center data and limited acquisition parameters.Purpose: Develop a generalizable CNN for lung segmentation in 1H-MRI, robust to pathology, acquisition protocol, vendor, and center.Study type: Retrospective.Population: A total of 809 1H-MRI scans from 258 participants with various pulmonary pathologies (median age (range): 57 (6–85); 42% females) and 31 healthy participants (median age (range): 34 (23–76); 34% females) that were split into training (593 scans (74%); 157 participants (55%)), testing (50 scans (6%); 50 participants (17%)) and external validation (164 scans (20%); 82 participants (28%)) sets.Field Strength/Sequence: 1.5-T and 3-T/3D spoiled-gradient recalled and ultrashort echo-time 1H-MRI.Assessment: 2D and 3D CNNs, trained on single-center, multi-sequence data, and the conventional spatial fuzzy c-means (SFCM) method were compared to manually delineated expert segmentations. Each method was validated on external data originating from several centers. Dice similarity coefficient (DSC), average boundary Hausdorff distance (Average HD), and relative error (XOR) metrics to assess segmentation performance.Statistical Tests: Kruskal–Wallis tests assessed significances of differences between acquisitions in the testing set. Friedman tests with post hoc multiple comparisons assessed differences between the 2D CNN, 3D CNN, and SFCM. Bland–Altman analyses assessed agreement with manually derived lung volumes. A P value of &lt;0.05 was considered statistically significant.Results: The 3D CNN significantly outperformed its 2D analog and SFCM, yielding a median (range) DSC of 0.961 (0.880–0.987), Average HD of 1.63 mm (0.65–5.45) and XOR of 0.079 (0.025–0.240) on the testing set and a DSC of 0.973 (0.866–0.987), Average HD of 1.11 mm (0.47–8.13) and XOR of 0.054 (0.026–0.255) on external validation data.Data Conclusion: The 3D CNN generated accurate 1H-MRI lung segmentations on a heterogenous dataset, demonstrating robustness to disease pathology, sequence, vendor, and center.Evidence Level: 4.Technical Efficacy: Stage 1.</p

    Cumulative exposure to air pollution and long term outcomes after first acute myocardial infarction: A population-based cohort study. Objectives and methodology

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    <p>Abstract</p> <p>Background</p> <p>Cardiovascular disease is a leading cause of morbidity and mortality worldwide and epidemiological studies have consistently shown an increased risk for cardiovascular events in relation to exposure to air pollution. The Israel Study of First Acute Myocardial Infarction was designed to longitudinally assess clinical outcomes, psychosocial adjustment and quality of life in patients hospitalized with myocardial infarction. The current study, by introducing retrospective air pollution data, will examine the association between exposure to air pollution and outcome in myocardial infarction survivors. This report will describe the methods implemented and measures employed. The study specifically aims to examine the relationship between residential exposure to air pollution and long-term risk of recurrent coronary event, heart failure, stroke, cardiac and all-cause death in a geographically defined cohort of patients with myocardial infarction.</p> <p>Methods/Design</p> <p>All 1521 patients aged ≤65 years, admitted with first myocardial infarction between February 1992 and February 1993 to the 8 hospitals serving the population of central Israel, were followed for a median of 13 years. Data were collected on sociodemographic, clinical and environmental factors. Data from air quality monitoring stations will be incorporated retrospectively. Daily measures of air pollution will be summarised, allowing detailed maps to be developed in order to reflect chronic exposure for each participant.</p> <p>Discussion</p> <p>This study addresses some of the gaps in understanding of the prognostic importance of air pollution exposure after myocardial infarction, by allowing a sufficient follow-up period, using a well-defined community cohort, adequately controlling for multiple and multilevel confounding factors and providing extensive data on various outcomes.</p
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