962 research outputs found

    Improving condition indicators for helicopter health and usage monitoring systems

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    Purpose – The purpose of this paper is to suggest new method for improving the condition indicators (CIs) used in health and usage monitoring system based on signal separation of gears. Design/methodology/approach – The research method is based on employing signal separation techniques to improve gears signal and fault signature. The signal separation is based on adaptive filters concept. Findings – CIs estimated for the deterministic part of vibration signal show higher sensitivity to gears faults in comparison to indicators estimated based on the original signal. This method proposed could enhance early fault detection in gears, particularly for those applications where strong background noise from other sources in the machine masks the characteristics fault components. Originality/value – The contribution of this research is improving the CIs currently used for helicopter gearboxes. As consequence the safe operation and availability will be improved. </jats:sec

    Low Speed Bearing Condition Monitoring – A Case Study

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    The heath condition of worm-wheel gearbox is critical for the reliable and continuous operation of passenger escalators. The vibration sensor has been widely installed in the gearbox and the vibration level is usually utilized as a health indicator. However, vibration level is not robust in slow speed bearing condition monitoring. In this paper, the health condition of two slow speed bearings was evaluated using vibration data collected from sensors installed in the shaft. It has been shown that the vibration level fails to indicator the bearing health condition. The assessment accuracy can be improved by combining several simple methods

    Bearing Signal Separation of Commercial Helicopter Main Gearbox

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    Gears are significant component in a multiplicity of industrial applications such as machine tool and gearboxes. An unforeseen failure of gear may result in significant economic losses. Therefore this research propose fault detection improvement throught series of vibration signal processing techuiques. These techniques have been tested experimentally using vibration data collected from the transmission system of a CS-29 ‘Category A’ helicopter gearbox under different bearing damage severity of the second planetary stage. Results showed successful improvement of bearing fault detection

    The effects of farmer attitudes and farm management practices on soil quality: a study in Cherokee County, Iowa

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    This study seeks to relate farmer attitudes, perceptions, and management characteristics to field soil quality and laboratory fertility indicators. Farmer interviews were conducted to document recent practices on the farm as well as farmer attitudes about farming. To obtain soil quality measures, both the Natural Resource Conservation Service\u27s field soil quality kit and laboratory tests were employed. Sites from the eastern half of Cherokee County, Iowa, were selected.;Key considerations of this study included farmer practices of renting versus owning land and organic or synthetic nitrogen application. Additional farmer data, including attitudes about farming, are used in this analysis.;In our study, farmers with longer farming experience had access to larger acreages. Also farmers with larger farms tended to adopt no till systems. When asked how they would change their operation if provided with unlimited resources, farmers who make decisions based upon simplicity and economics are more likely to continue their operation as is, while those who use experience, trial and error, as well as experimentation as their primary decision making tools are more likely to scale back their operations.;It was observed that ownership was not directly an influencing factor in shaping soil quality. However, some of the farmers\u27 traits and attributes led to management activities that significantly impacted selected soil quality and fertility indices. The use of organic and inorganic amendments had not led to significantly different potassium or phosphorus levels in the fields. Fields of farmers with large acreages had lower microbial respiration and higher pH. The no-till systems adopted by farmers with large acreages were associated with soils with higher bulk density. Farmers who viewed farming as only labor or management had fields with higher bulk densities and nitrate levels than those who viewed farming as a multifaceted profession. Additionally, farmers who enjoyed farming had fields with lower bulk densities than those who farmed simply to make a living

    Role of Endomucin in Hypoxia-Induced Retinopathy of Prematurity

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    Retinopathy of prematurity (ROP) is a major cause of blindness among premature, low birth weight infants as a result of pathological angiogenesis. Angiogenesis, the growth of new blood vessels from preexisting vessels, occurs in the veins and capillaries of the body. The process is highly regulated during early development and maturation. However, under abnormal conditions such as a decrease in oxygen levels or hypoxia, angiogenesis can become dysregulated and pathogenic. Currently, the best treatment for ROP is laser therapy, which does not significantly improve vision. Alternatively, glycoproteins are believed to play an important role in angiogenesis. Endomucin (EMCN), a glycoprotein, has been shown to be expressed by the venous and capillary endothelium. EMCN is believed to be associated with angiogenesis and could be a potential target for treatment of ROP. Thus, we hypothesize that EMCN is regulated by hypoxia and plays an important role in pathological angiogenesis. Human retinal endothelial cells (HRECs), representative of endothelial cells involved in retinal angiogenesis, were deprived of oxygen using a hypoxia chamber. We established the optimal oxygen dosage, determined the optimal cell density, and monitored EMCN expression at different time points after exposure to hypoxia. Changes in gene expression in response to hypoxia were compared to control cells. Our preliminary data indicates that EMCN is regulated by hypoxia. Currently, we are investigating whether EMCN has similar effects in regulating revascularization in vivo. Taken together, our study indicates a novel role for EMCN during hypoxia-induced angiogenesis which may serve as a therapeutic target

    Unlocking the Doors to Patient Satisfaction in Pediatric Orthopaedics

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    Background Many hospitals continue to struggle to improve patient satisfaction as the identification of tangible quality improvement areas remains difficult Medicare hospital payments are linked to patient satisfaction and hospitals\u27 HCAHPS scores, which has contributed to the growing influence of patient satisfaction measures Investigation into the major drivers of patient satisfaction in the pediatric clinical arena has not been thoroughly pursued To determine the main drivers of patient experience in pediatric orthopaedics, we performed an analysis of patient satisfaction surveys collected from outpatient pediatric orthopaedic practices at 5 locations in 3 states Hypothesis: the patient-physician relationship is the most important factor in patients\u27 assessment of their experiences These results may have significance in aiding pediatric orthopaedic clinics in their Quality Assurance/Quality Improvement plans of enhancing the patient experiencehttps://jdc.jefferson.edu/pedsposters/1000/thumbnail.jp

    A study on helicopter main gearbox planetary bearing fault diagnosis

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    The condition monitoring of helicopter main gearbox (MGB) is crucial for operation safety, flight airworthiness and maintenance scheduling. Currently, the helicopter health and usage monitoring system, HUMS, is installed on helicopters to monitor the health state of their transmission systems and predict remaining useful life of key helicopter components. However, recent helicopter accidents related to MGB failures indicate that HUMS is not sensitive and accurate enough to diagnose MGB planetary bearing defects. To contribute in improving the diagnostic capability of HUMS, diagnosis of a MGB planetary bearing with seeded defect was investigated in this study. A commercial SA330 MGB was adopted for the seeded defect tests. Two test cases are demonstrated in this paper: the MGB at 16,000 rpm input speed with 180 kW load and at 23,000 rpm input speed with 1760 kW load. Vibration data was recorded, and processed using signal processing techniques including self-adaptive noise cancellation (SANC), kurtogram and envelope analysis. Processing results indicate that the seeded planetary bearing defect was successfully detected in both test cases
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