9,844 research outputs found

    Development of a mercury electromagnetic centrifugal pump for the SNAP-8 refractory boiler development program

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    An electromagnetic pump, in which pressure is developed in mercury because of the interaction of the magnetic field and current which flows as a result of the voltage induced in the mercury contained in the pump duct, was developed for the SNAP-8 refractory boiler test facility. Pump performance results are presented for ten duct configurations and two stator sizes. These test results were used to design and fabricate a pump which met the SNAP-8 criteria of 530 psi developed pressure at 12,500 lb/hr. The pump operated continuously for over 13,000 hours without failure or performance degradation. Included in this report are descriptions of the experimental equipment, measurement techniques, all experimental data, and an analysis of the electrical losses in the pump

    The genealogy of judgement: towards a deep history of academic freedom

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    The classical conception of academic freedom associated with Wilhelm von Humboldt and the rise of the modern university has a quite specific cultural foundation that centres on the controversial mental faculty of 'judgement'. This article traces the roots of 'judgement' back to the Protestant Reformation, through its heyday as the signature feature of German idealism, and to its gradual loss of salience as both a philosophical and a psychological concept. This trajectory has been accompanied by a general shrinking in the scope of academic freedom from the promulgation of world-views to the offering of expert opinion

    Deer reduce habitat quality for a woodland songbird: evidence from settlement patterns, demographic parameters, and body condition.

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    Understanding avian responses to ungulate-induced habitat modification is important because deer populations are increasing across much of temperate Europe and North America. Our experimental study examined whether habitat quality for Blackcaps (Sylvia atricapilla) in young woodland in eastern England was affected by deer, by comparing Blackcap behavior, abundance, and condition between paired plots (half of each pair protected from deer). The vegetation in each pair of plots was the same age. The Blackcap is an ideal model species for testing effects of deer on avian habitat quality because it is dependent on dense understory vegetation and is abundant throughout much of Europe. We compared timing of settlement, abundance, age structure (second-year vs. after-second-year), and phenotypic quality (measured as a body condition index, body mass divided by tarsus length) between experimental and control plots. We used point counts to examine Blackcap distribution, and standardized mist netting to collect demographic and biometric data. Incidence of singing Blackcaps was higher in nonbrowsed than in browsed plots, and singing males were recorded in nonbrowsed plots earlier in the season, indicating earlier and preferential territory establishment. Most Blackcaps, both males and females, were captured in vegetation prior to canopy closure (2–4 years of regrowth). Body condition was superior for male Blackcaps captured in nonbrowsed plots; for second-year males this was most marked in vegetation prior to canopy closure. We conclude that deer browsing in young woodland can alter habitat quality for understory-dependent species, with potential consequences for individual fitness and population productivity beyond the more obvious effects on population density

    Three dimensional laser Doppler velocimeter turbulence measurements in a pipe flow

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    The mean and turbulent u, v, and w components of a gaseous fully developed turbulent pipe flow were measured with a laser Doppler velocimeter system. Measurements of important system parameters are presented and discussed in relation to the measurement accuracy. Simultaneous comparisons of the laser Doppler and hot wire anemometer measurements in the turbulent flow provided evidence that the two systems were responding to the same flow phenomena

    EFFECT OF PROPOSED GRAIN STANDARDS ON MARKETING COSTS OF THE U.S. SORGHUM SECTOR: AN INTERREGIONAL TRANSSHIPMENT-PLANT LOCATION MODEL

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    Recent legislative initiatives call for studies to evaluate costs associated with cleaning U.S. grains to meet more stringent standards. This paper reports on a study which developed a mixed-integer programming model of the U.S. sorghum sector to (1) determine the least-cost geographic location for new cleaning investment at the country, terminal and port elevator stages of the marketing system and (2) measure additional system marketing costs associated with implementing the proposed standards. Results show the least-cost cleaning location to be at country and terminal elevators in excess supply regions. Implementing the proposed standard would increase system costs about 2 percent.Grain quality, Plant location, Sorghum, Mixed-integer, Crop Production/Industries, Marketing,

    Comparison of meadow-kill treatments on a corn-oats-meadow-meadow rotation in northwestern Iowa

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    An experiment was conducted at the Moody Research Center (formerly Moody Experimental Farm) in northwestern Iowa to examine the effects of meadow-kill on crop yields and on soil moisture in the spring. The experiment utilized a corn-oats-meadow-meadow rotation with meadow-kill treatments applied to the second-year meadow at various times of the growing season. Twenty years (1958-1977) of data were used for the analyses presented in this bulletin. Three treatments were used in the experiment. In the first, the control treatment, the second-year meadow was harvested two or three times. The plots were plowed the following spring before corn was planted. The second treatment was a short fallow” treatment, in which second-year meadow was killed with herbicides in the early fall after the second cutting of hay. The third treatment was a longer fallow treatment, with meadow killed in midsummer after the first hay cutting. Plots receiving the second and third treatments also were spring plowed

    Real-time depth sectioning: Isolating the effect of stress on structure development in pressure-driven flow

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    Transient structure development at a specific distance from the channel wall in a pressure-driven flow is obtained from a set of real-time measurements that integrate contributions throughout the thickness of a rectangular channel. This “depth sectioning method” retains the advantages of pressure-driven flow while revealing flow-induced structures as a function of stress. The method is illustrated by applying it to isothermal shear-induced crystallization of an isotactic polypropylene using both synchrotron x-ray scattering and optical retardance. Real-time, depth-resolved information about the development of oriented precursors reveals features that cannot be extracted from ex-situ observation of the final morphology and that are obscured in the depth-averaged in-situ measurements. For example, at 137 °C and at the highest shear stress examined (65 kPa), oriented thread-like nuclei formed rapidly, saturated within the first 7 s of flow, developed significant crystalline overgrowth during flow and did not relax after cessation of shear. At lower stresses, threads formed later and increased at a slower rate. The depth sectioning method can be applied to the flow-induced structure development in diverse complex fluids, including block copolymers, colloidal systems, and liquid-crystalline polymers

    Saturn's Seismic Rotation Revisited

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    Normal mode seismology is a promising means of measuring rotation in gas giant interiors, and ring seismology presents a singular opportunity to do so at Saturn. We calculate Saturn's normal modes of oscillation and zonal gravity field, using nonperturbative methods for normal modes in the rigidly rotating approximation, and perturbative methods for the shifts that Saturn's deep winds induce in the mode frequencies and zonal gravity harmonics. The latter are calculated by solving the thermo-gravitational wind equation in an oblate geometry. Comparing many such models to gravity data and the frequencies of ring patterns excited by Saturn normal modes, we use statistical methods to estimate that Saturn's cloud-level winds extend inward along cylinders before decaying at a depth 0.125-0.138 times Saturn's equatorial radius, or 7,530-8,320 km, consistent with analyses of Cassini gravity and magnetic field data. The seismology is especially useful for pinning down Saturn's poorly constrained deep rotation period, which we estimate at 634.7 min (median) with a 5/95% quantile range 633.8-635.5 min. Outstanding residuals in mode frequencies at low angular degree suggest a more complicated deep interior than has been considered to date. Smaller but still significant residuals at high angular degree also show that our picture for the thermal, composition, and/or rotation profile in Saturn's envelope is not yet complete.Comment: Accepted to PS

    1961 Payton Lectures: The Preacher\u27s Portrait

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    Fuller Theological Seminary instituted the Payton Lectures in 1948, providing for a series of divinity lectures by a notable scholar outside the regular faculty. The lectureship is named for Dr. John E. and Mrs. Eliza Payton, parents of the late Mrs. Grace Fuller, wife of seminary founder Charles E. Fuller. El Seminario Teológico de Fuller instituyó las Conferencias Payton en 1948, proveyendo una serie de conferencias en divinidades por una persona erudita de renombre fuera de la facultad regular. Las conferencias llevan el nombre del Dr. John E. y la Sra. Eliza Payton, padres de la fallecida Sra. Grace Fuller, esposa del fundador del seminario Charles E. Fuller. 풀러신학대학원은 1948년 페이튼 강좌를 개설하여 정규 교수진 외에 저명한 학자의 신학 강연을 제공해왔습니다. 강좌의 명칭은 학교 설립자 찰스 풀러 (Charles E. Fuller)의 아내인 그레이스 풀러 (Grace Fuller) 부인의 양친 존 페이튼 (John E. Payton) 박사와 엘리자 페이튼 (Eliza Payton) 부인의 이름을 따라 붙여졌습니다
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