1,455 research outputs found
Atmospheric effects on the underground muon intensity
It has previously been reported that the barometric pressure coefficient observed for muons at Poatina (vertical absorber depth 357 hg/sq cm) appears to be appreciably higher than would be expected from atmospheric absorption alone. There is a possibility that the effect is due to an upper atmospheric temperature effect arising from an inverse correlation of surface pressure with stratospheric temperature. A new proportional telescope is discussed which has been operating at Poatina since about the beginning of 83 and which has a long term stability suitable for studying variations of atmospheric origin
Cavity Reactor Engineering Mockup Critical Experiment
Critical mass of uranium 235 for stainless steel lined cavities in nuclear research and test reactors with heavy water reflecto
Some Nuclear Calculations of U-235-D2O Gaseous-Core Cavity Reactors
The results of a multigroup, diffusion theory study of spherical gaseous-core cavity reactors are presented in this report. The reactor cavity of gaseous U235 is enclosed by a region of hydrogen gas and is separated from an external D2O moderator-reflector by a zirconium structural shell. Some cylindrical reactors are also investigated. A parametric study of spherical reactors indicates that, for the range of variables studied, critical mass increases as: (1) Fuel region is compressed within the reactor cavity, (2) moderator thickness is decreased, (3) structural shell thickness is increased, and (4) moderator temperature is increased. A buckling analogy is used to estimate the critical mass of fully reflected cylindrical reactors from spherical results without fuel compression. For a reactor cavity of a 120-centimeter radius uniformly filled with fuel, no structural shell, a moderator temperature of 70 F, and a moderator thickness of 100 centimeters, the critical mass of a spherical reactor is 3.1 kilograms while that of a cylinder with a length-to-diameter ratio of 1.0 (L/D = 1) is approximately 3.8 kilograms and, with L/D = 2, 5.9 kilograms. For the range of variables considered for U235-D2O gaseous-core cavity reactors, the systems are characterized by 95 to 99 percent thermal absorptions, with the flux reaching a maximum in the moderator about 10 to 15 centimeters from the reactor cavity
Application of maximum entropy optimal projection design synthesis to a benchmark problem
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76995/1/AIAA-20955-739.pd
Layer by layer - Combining Monads
We develop a method to incrementally construct programming languages. Our
approach is categorical: each layer of the language is described as a monad.
Our method either (i) concretely builds a distributive law between two monads,
i.e. layers of the language, which then provides a monad structure to the
composition of layers, or (ii) identifies precisely the algebraic obstacles to
the existence of a distributive law and gives a best approximant language. The
running example will involve three layers: a basic imperative language enriched
first by adding non-determinism and then probabilistic choice. The first
extension works seamlessly, but the second encounters an obstacle, which
results in a best approximant language structurally very similar to the
probabilistic network specification language ProbNetKAT
The Unusual Infrared Object IRC+10216
IRC+10216 is an extended object located out of the galactic plane in an unreddened region. At 5 μ it is the brightest source observed outside the solar system; at 2.2 μ it varies by as much as 2 mag, with a time scale on the order of 600 days. Its energy distribution resembles that of a 650° K blackbody, and no spectral features have been observed in the wavelength range from 1.5 to 14 μ. The object is interpreted as being consistent with a galactic source surrounded by an optically thick dust shell
Temperature seasonality in the North American continental interior during the Early Eocene Climatic Optimum
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/148644/1/Hyland_et_al_2018_CotP-Eocene_Climate_Equability.pd
Temperature seasonality in the North American continental interior during the Early Eocene Climatic Optimum
Paleogene greenhouse climate equability has long been a paradox in
paleoclimate research. However, recent developments in proxy and modeling
methods have suggested that strong seasonality may be a feature of at least
some greenhouse Earth periods. Here we present the
first multi-proxy record of seasonal temperatures during the Paleogene from
paleofloras, paleosol geochemistry, and carbonate clumped isotope thermometry
in the Green River Basin (Wyoming, USA). These combined temperature records
allow for the reconstruction of past seasonality in the continental interior,
which shows that temperatures were warmer in all seasons during the peak
Early Eocene Climatic Optimum and that the mean annual range of temperatures was high,
similar to the modern value ( ∼ 26 °C). Proxy data and
downscaled Eocene regional climate model results suggest amplified
seasonality during greenhouse events. Increased seasonality reconstructed for
the early Eocene is similar in scope to the higher seasonal range predicted
by downscaled climate model ensembles for future high-CO2 emissions
scenarios. Overall, these data and model comparisons have substantial
implications for understanding greenhouse climates in general, and may be
important for predicting future seasonal climate regimes and their impacts in
continental regions.</p
Intervention and revision: Expertise and interaction in text mediation
Many EAL (English as an Additional Language) scholars enlist text mediators’ support when faced with the challenges of writing for international publication. However, the contributions these individuals are able to make in improving scientific manuscripts remains unclear, especially when language professionals such as English teachers do this work. In this article, we explore this topic by examining how three mediators employed their very different expertise and brought different processes to bear on the same discussion section of a medical manuscript written by a novice scholar in China. We find that successfully mediated texts are often the result of an interplay between the mediator’s expertise and the relationship between the participants. Our findings contradict those of previous studies that question the role of English teachers in this process and have the potential to inform both text mediation practices and revision studies
- …