2,317 research outputs found
Experimentally Observed Instability of a Laminar Ekman Flow in a Rotating Basin
In studying the axi-symmetric flow induced by source-sink distributions in a rotating cylindrical
basin in the absence of radial barriers, a highly organized pattern of instability has been
observed in the laminar Ekman layer along the bottom of the basin. The instability manifests
itself in the form of almost perfectly concentric cylindrical sheets or curtains of water which
rise as sharply defined vertical jets from the Ekman layer and penetrate the entire depth of
fluid. A less sharply defined downward motion between the curtains completes the circulation
celis thus developed. At some maximum critical radius, the curtains usually disappear, and the
flow at larger radii is a stable, laminar Ekman flow. Quantitative observations of ring spacing
and critical radius are reported for experiments in which angular velocity, flow rate, viscosity
and total depth of water were varied over experimentally available ranges
Evaluation of the application of ERTS-1 data to the regional land use planning process
The author has identified the following significant results. Employing simple and economical extraction methods, ERTS can provide valuable data to the planners at the state or regional level with a frequency never before possible. Interactive computer methods of working directly with ERTS digital information show much promise for providing land use information at a more specific level, since the data format production rate of ERTS justifies improved methods of analysis
Non-Scanning Radiometer Results for Earth Radiation Budget Investigations
The Earth Radiation Budget Experiment (ERBE) included non-scanning radiometers (Luther, 1986) flown aboard a dedicated mission of Earth Radiation Budget Satellite, and the NOAA-9 and -10 operational meteorological spacecraft (Barkstrom and Smith, 1986). The radiometers first began providing Earth radiation budget data in November 1984 and have remained operational, providing a record of nearly 8 years of data to date for researchers. Although they do not produce measurements with the resolution given by the scanning radiometers, the results from the non-scanning radiometers are extremely useful for climate research involving long-term radiation data sets. This paper discusses the non-scanning radiometers, their stability, the method of analyzing the data, and brief scientific results from the data
Supernova Remnants in the Fossil Starburst in M82
We report the discovery of ten compact H-alpha-bright sources in the
post-starburst region northeast of the center of M82, ``M82 B.'' These objects
have H alpha luminosities and sizes consistent with Type II supernova remnants
(SNRs). They fall on the same H alpha surface brightness-diameter (Sigma-D)
relation defined by SNRs in other nearby star-forming galaxies, with the M82
candidates lying preferentially at the small diameter end. These are the first
candidates for optically-visible SNRs in M82 outside the heavily obscured
central starburst within ~250 pc from the galactic center. If these sources are
SNRs, they set an upper limit to the end of the starburst in region ``B2,''
about 500 pc from the galaxy's core, of ~50 Myr. Region ``B1,'' about 1000 pc
from the core, lacks good SNR candidates and is evidently somewhat older. This
suggests star formation in the galaxy has propagated inward toward the
present-day intense starburst core.Comment: Re-submitted to AJ, referee's comments taken into account, 15 pages
LaTeX preprint style, 4 postscript figures; full-resolution figures available
from http://www.astro.virginia.edu/~rd7a/snrs/ Changes: minor textual changes
and orientation/axes of Fig.
Quantized gravitational waves in the Milne universe
The quantization of gravitational waves in the Milne universe is discussed.
The relation between positive frequency functions of the gravitational waves in
the Milne universe and those in the Minkowski universe is clarified.
Implications to the one-bubble open inflation scenario are also discussed.Comment: 26 pages, 1 figure, revtex. submitted to Phys. Rev. D1
The value of prognostic factors for uterine cervical cancer patients treated with irradiation alone
<p>Abstract</p> <p>Background</p> <p>The aim of our study was to investigate and evaluate the prognostic value of and correlations between preclinical and clinical factors such as the stage of the disease, blood Hb level before treatment, size of cervix and lymph nodes evaluated by CT, age, dose of irradiation and duration of radiotherapy related to overall survival, disease-free survival, local control and metastases-free survival in cervical cancer patients receiving radiotherapy alone.</p> <p>Methods</p> <p>162 patients with International Federation of Gynecology and Obstetrics (FIGO) stage IIA-IIIB cervical carcinoma treated with irradiation were analysed. Univariate and multivariate analyses using the Cox regression model were performed to determine statistical significance of some tumor-related factors.</p> <p>Results</p> <p>The Hb level before treatment showed significant influence on overall survival (p = 0.001), desease free survival (p = 0.040) and local control (p = 0.038). The lymph node status (>10 mm) assessed on CT had impact on overall survival (p = 0,030) and local control (p = 0,036). The dose at point A had impact on disease free survival (p = 0,028) and local control (p = 0,021) and the radiotherapy duration had showed significant influence on overall survival (p = 0,045), disease free survival (p = 0,006) and local control (p = 0,033).</p> <p>Conclusion</p> <p>Anemia is a significant and independent prognostic factor of overall survival, disease-free survival and local control in cervical cancer patients treated with irradiation. The size of lymph nodes in CT is an independent prognostic factor for overall survival and local control in cervical cancer patients. The size of cervix uteri evaluated by CT has no prognostic significance in cervical cancer patients treated with radiotherapy. The prognostic value of FIGO stage of cervical cancer is influenced by other factors, analyzed in this study and is not an independent prognostic factor.</p
Contamination Control and Assay Results for the Majorana Demonstrator Ultra Clean Components
The MAJORANA DEMONSTRATOR is a neutrinoless double beta decay experiment
utilizing enriched Ge-76 detectors in 2 separate modules inside of a common
solid shield at the Sanford Underground Research Facility. The DEMONSTRATOR has
utilized world leading assay sensitivities to develop clean materials and
processes for producing ultra-pure copper and plastic components. This
experiment is now operating, and initial data provide new insights into the
success of cleaning and processing. Post production copper assays after the
completion of Module 1 showed an increase in U and Th contamination in finished
parts compared to starting bulk material. A revised cleaning method and
additional round of surface contamination studies prior to Module 2
construction have provided evidence that more rigorous process control can
reduce surface contamination. This article describes the assay results and
discuss further studies to take advantage of assay capabilities for the purpose
of maintaining ultra clean fabrication and process design.Comment: Proceedings of Low Radioactivity Techniques (LRT May 2017, Seoul
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