4,123 research outputs found

    Experimental pressure drop investigation of wetting and nonwetting mercury condensing in uniformly tapered tubes

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    Pressure drop of wetting and nonwetting mercury condensing in tapered tubes - turbogenerator system

    Sound radiation from a high speed axial flow fan due to the inlet turbulence quadrupole interaction

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    A formula is obtained for the total acoustic power spectra radiated out the front of the fan as a function of frequency. The formula involves the design parameters of the fan as well as the statistical properties of the incident turbulence. Numerical results are calculated for values of the parameters in the range of interest for quiet fans tested at the Lewis Research Center. As in the dipole analysis, when the turbulence correlation lengths become equal to the interblade spacing, the predicted spectra exhibit peaks around the blade passing frequency and its harmonics. There has recently been considerable conjecture about whether the stretching of turbulent eddies as they enter a stationary fan could result in the inlet turbulence being the dominant source of pure tones from nontranslating fans. The results of the current analysis show that, unless the turbulent eddies become quite elongated, this noise source contributes predominantly to the broadband spectrum

    Electron-phonon coupling in semimetals in a high magnetic field

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    We consider the effect of electron-phonon coupling in semimetals in high magnetic fields, with regard to elastic modes that can lead to a redistribution of carriers between pockets. We show that in a clean three dimensional system, at each Landau level crossing, this leads to a discontinuity in the magnetostriction, and a divergent contribution to the elastic modulus. We estimate the magnitude of this effect in the group V semimetal Bismuth.Comment: 2 figure

    The use of a battery of tracking tests in the quantitative evaluation of neurological function

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    A tracking test battery has been applied in a drug trail designed to compare the efficacy of L-DOPA and amantadine to that of L-DOPA and placebo in the treatment of 28 patients with Parkinson's disease. The drug trial provided an ideal opportunity for objectively evaluating the usefulness of tracking tests in assessing changes in neurologic function. Evaluating changes in patient performance resulting from disease progression and controlled clinical trials is of great importance in establishing effective treatment programs

    Patterns of sensory nerve conduction abnormalities in demyelinating and axonal peripheral nerve disorders

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    The pattern of an abnormal median-normal sural (AMNS) sensory response is associated with acute and chronic inflammatory demyelinating polyradiculoneuropathy (AIDP and CIDP) and considered unusual in other types of neuropathy, although specificity and sensitivity of this pattern have not been evaluated. We compared sensory responses (patterns and absolute values) in patients with AIDP, CIDP, diabetic polyneuropathy (DP), and motor neuron disease (MND). Using strict criteria, the AMNS pattern occurred more frequently in recent onset AIDP (39%) compared with CIDP (28%), DP (14%–23%), or MND (22%) patients. This pattern was found in 3% of control subjects. The extreme pattern of an absent median-present sural response occurred only in AIDP and CIDP patients and in no other groups. Abnormalities of both nerves were more common in long-standing polyneuropathies such as CIDP and DP compared with AIDP or MND. Median nerve amplitudes were reduced significantly in AIDP, CIDP, and DP patients compared with MND patients, whereas sural nerve amplitudes were significantly reduced only in DP and CIDP patients. These findings may reflect early distal nerve involvement particularly in AIDP patients which is highlighted by differences in median and sural nerve recording electrode placement. We conclude that, in the appropriate clinical setting, the AMNS pattern, an absent median-present sural response pattern, or a reduced median amplitude compared with the sural amplitude supports a diagnosis of a primary demyelinating polyneuropathy. © 1993 John Wiley & Sons, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/50157/1/880160304_ftp.pd

    Biochemical composition of red, green and brown seaweeds on the Swedish west coast

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    Seaweed biomass has the potential to become an important raw material for bio-based production. The aim of this study was to screen the overall composition of several seaweed species on the Swedish west coast, including some scarcely studied species, to provide fundamentals for evaluation of biorefining potential and to benchmark with already potentially industrially relevant species and commercially important land-based biomasses. Twenty-two common seaweed species (green, red, brown) were collected and the carbohydrate, ash, protein, water and metal contents were measured. Carbohydrate content varied between 237 and 557\ua0g\ua0kg−1 dry weight (dw), making it the largest constituent, on a dry weight basis, of most species in the study. Ash, which is considered unwanted in biorefining, ranged between 118 and 419\ua0g\ua0kg−1 dw and was the largest constituent in several seaweeds, which were therefore considered unsuitable for biorefining. Protein content was most abundant in the red seaweeds but was generally low in all species (59–201\ua0g\ua0kg−1 dw). High contents of several unwanted metals for processing or human consumption were found (e.g. aluminium, arsenic, copper, chromium and nickel), which need to be considered when utilizing seaweeds for certain applications. Potential targets for further biorefinery development mostly include species already known for their potential (Saccharina latissima, Laminaria digitata and Chondrus crispus) while some, such as Halidrys siliquosa and Dilsea carnosa, have not been previously noted. However, more detailed studies are required to explore biorefinery processes for these seaweeds, as well as how to potentially cultivate them

    Black Bears Recolonizing Historic Ranges: Indiana Human–Bear Interactions

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    Over a century after extirpation from Indiana, USA, 2 American black bears (Ursus americanus) were confirmed in the state during the summers of 2015 and 2016. The first bear encountered a public and management agency unaccustomed to living with large carnivores, which resulted in intentional and unintentional feedings, habituation, and ultimately its euthanasia. The Indiana Department of Natural Resources (DNR) attempted to learn from this encounter and began preparing for the next transient black bear. Education materials were created to help minimize human–bear interactions, promote living safely with bears, and inform about what to do when encountering a bear. Additionally, bear traps were purchased and staff were trained to safely deploy and use these traps. During the summer of 2016, when a second black bear was confirmed in Indiana, the DNR deployed targeted education and outreach materials to try to help maintain a positive living-with-bears environment and minimize human–bear interactions. Expanded public education and a slight increase in preparedness of the DNR provided 2 different outcomes for the recent bears in Indiana. These are likely not the last bears Indiana will host; habitat suitability models suggest that Indiana could potentially support bears in portions of the state. Natural range expansion in neighboring states suggest that Indiana will see more black bears in the future. These 2 bears highlighted the need for Indiana and other state agencies to have some preparations in place—especially related to education—to respond to transient large carnivores that are moving through and eventually recolonizing long extirpated areas
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