4,470 research outputs found

    Performance of a straight stator and a tilted stator tested with a high-solidity high-pressure-ratio transonic rotor

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    Overall stage and stator blade element performance with straight stator and tilted stator in transonic axial flow compressor stag

    Effective thermal conductivities of four metal ceramic composite coatings in hydrogen-oxygen rocket firings

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    An experimental investigation was conducted to determine the effective conductivities of four plasma-arc-sprayed, metal-ceramic gradated coatings on hydrogen-oxygen thrust chambers. The effective thermal conductivities were not a function of pressure or oxidant-to-fuel ratio. The various materials that made up these composites do not seem to affect the thermal conductivity values as much as the differences in the thermal conductivities of the parent materials would lead one to expect. Contact resistance evolving from the spraying process seems to be the controlling factor. The thermal conductivities of all the composites tested fell in the range of 0.75 to 7.5 watts per meter kelvin

    Reliability and effective thermal conductivity of three metallic-ceramic composite insulating coatings on cooled hydrogen-oxygen rockets

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    An experimental investigation of the structural integrity and effective thermal conductivity of three metallic-ceramic composite coatings was conducted. These coatings were plasma sprayed onto the combustion side of water-cooled, 12.7-centimeter throat diameter, hydrogen-oxygen rocket thrust chambers operating at 2.07 to 4.14 meganewtons per square meter chamber pressure. The metallic-ceramic composites functioned for six to 17 cycles and for as long as 213 seconds of rocket operations and could have probably provided their insulating properties for many additional cycles. The effective thermal conductivity of all the coatings was in the range of 0.7472 to 4.483 w/(m)(K), which makes the coatings a very effective thermal barrier. Photomicrographic studies of cross-sectioned coolant tubes seem to indicate that the effective thermal conductivity of the coatings is controlled by contact resistance between the particles, as a result of the spraying process, and not the thermal conductivity of the bulk materials

    Sound Stimulates Labeling of Polyphosphoinositides in the Auditory Organ of the Noctuid Moth

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    The Noctuid moth possesses a simple auditory structure suitable for the investigation of biochemical correlates of sound stimulation in vivo. Stimulation with pulsed tones increased 32 P incorporation into polyphos-phoinositides but not into ATP or other lipids. The effect was seen in the scoloparium (sensory structure) but hot in the nodular sclerite, an adjacent nonsensory tissue. It was also not seen when the stimulus was a continuous tone, leading to adaptation of the action potential.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65812/1/j.1471-4159.1980.tb11201.x.pd

    Polyphosphoinositides in insect muscle and sensory tissues

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66128/1/j.1471-4159.1979.tb04538.x.pd

    Independent from muscle power and balance performance, a creatinine clearance below 65ml/min is a significant and independent risk factor for falls and fall-related fractures in elderly men and women diagnosed with osteoporosis

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    Summary: We assessed in a cross-sectional study in elderly men and women with osteoporosis, the association between the creatinine clearance (CrCl) and the performance in different balance and muscle power and function tests and found that a decreasing creatinine clearance was significantly associated with lower balance and muscle power. Introduction: To determine if a creatinine clearance of <65ml/min is significantly associated with decreasing muscle power and balance and an increased risk for falls and fractures. Methods: We assessed in a cross-sectional-study in 1781 German osteoporotic patients, the association between the CrCl, the physical performance, and the number of falls and fractures. Results: Controlling for age, gender, BMI, and osteoporosis treatment (fracture analysis only), a decreasing CrCl was associated with lower physical performance in the timed-up-and-go test (corr −0.2337, P < 0.0001), chair-rising test (corr −0.1706, P < 0.001), and tandem-stand test (corr 0.2193, P < 0.0001), and a CrCl of <65ml/min was associated with a significantly higher risk for falls (47.7% vs. 36.2%, P = 0.0008) and fall-related fractures (33.1% vs. 22.9%, P = 0.0003) compared with a CrCl of ≥65ml/min. Conclusions: In this study, we found a significant gender-independent correlation between decreasing CrCl and lower performance in balance and muscle power tests. Reduced muscle power and balance may therefore be involved in the low creatinine clearance associated increased risk for falls and fall-related fractures. Furthermore, we found that a CrCl <65ml/min., independent from the performance in muscle power, muscle function, and balance tests, is a significant risk factor for falls and fracture
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