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Lexington, MA, United States

Milikh G.M.,University of Maryland University College | Mishin E.,Air Force Research Lab | Galkin I.,University of Massachusetts Lowell | Vartanyan A.,University of Maryland University College | And 2 more authors.
Geophysical Research Letters | Year: 2010

New results of the DMSP satellite and HAARP digisonde observations during HF heating at the High-Frequency Active Auroral Program (HAARP) facility are described. For the first time, the DMSP satellites detected significant ion outflows associated with 10-30% density enhancements in the topside ionosphere above the heated region near the magnetic zenith. In addition, coincident high-cadence skymaps from the HAARP digisonde reveal field-aligned upward plasma flows inside the F-peak region. The SAMI2 2 model calculations are in fair agreement with the observations. Copyright © 2010 by the American Geophysical Union. Source

Gangopadhyay A.,University of Massachusetts Dartmouth | Bharat Raj G.N.,Indian Institute of Science | Chaudhuri A.H.,AER Inc. | Babu M.T.,National Institute of Oceanography of India | Sengupta D.,Indian Institute of Science
Geophysical Research Letters | Year: 2013

We present evidence that the springtime western boundary current (WBC) in the Bay of Bengal is a continuous northward-flowing current from about 12°N to 17°N, which then separates from the coast at around 18°N. We first revisit a hydrographic data set collected in 1987 from a potential vorticity perspective, and then analyze absolute dynamic height maps from satellite altimeters during the period 2000-2010. The altimetric maps suggest that the mean configuration of the WBC is that of an intense current with two anticyclonic eddies on the offshore side, which are part of the basin-wide anticyclonic circulation. The WBC consistently separates from the coast at around 18°N in all years between 2000 and 2010. The path of the eastward-flowing mean stream after separation appears to be consistent with isolines of f/H and with Ertel's potential vorticity, based on an analysis of the hydrographic data from 1987. © 2013 American Geophysical Union. All Rights Reserved. Source

Beck D.R.,Michigan Technological University | O'Malley S.M.,AER Inc.
Journal of Physics B: Atomic, Molecular and Optical Physics | Year: 2010

We complete the development of a relativistic energy-dependent efficient method by which important pair-correlation effects associated with open subshells can be incorporated into the relativistic configuration interaction (RCI) methodology. We apply this to predict the positions of the 4f 66s2 5DJ levels of Sm I. Relative to 5D1, we predict 5D0 lies at-1613 cm-1 and 5D4 at 6589 cm-1. For 5D2 and 5D3, we are 22 cm -1 and 123 cm-1 below the observed difference, respectively. We also calculate magnetic dipole transition rates among these levels and the ground-state 7FJ levels, which may be of interest to future parity nonconservation studies. © 2010 IOP Publishing Ltd. Source

Scott G.,AER Inc. | Smith L.M.,AER Inc.
SPE Production and Operations Symposium, Proceedings | Year: 2013

In multiple wells in the Williston Basin of North Dakota, introduction of a new reaming tool utilized for dedicated reaming and reaming-while-drilling operations has been introduced successfully in over 140 wells. This new tool has increased the percentage of packers going to total depth (TD) in a single trip in Williston Basin wells, where it is critical that wellbore condition enables multiple packers to be run and set at TD in a timely fashion in a single trip. Additionally enhanced packer design, in combination with a better understanding of well bore conditions as well as improved torque and drag reductions, has led to additional field successes. Historically this has not been the case in a number of wells, and information will be provided on certain of those instances. The reaming tools are currently bring used in reaming-while-drilling scenarios to eliminate the need for a dedicated reamer run in each well; this saves two to three rig days. These tools can be built as steel or non-magnetic (non-mag) tools; hence, they can be run anywhere in the BHA plus be used to drill out. They reduce spiraling in the well bore, thereby reducing the risk of sticking the liner assembly before reaching TD. Operators are 100% successful with packers going to TD when using this technology. In addition, current BHA modeling techniques and field use documents that use of the tools presents no significant steerability issues and no loss in penetration rate while still enabling subsequent installation of multiple packers. This proved critical in these North Dakota wells, where the application can require running as many as 35 swell packers to bottom. Also provided is input on certain packer designs that can be used in combination with these new reaming technologies to improve the chances for going to TD in a single run. Finally, the paper addresses the economic impact of this reamer application in what can be a half-million dollar operation per well, and notes the on-going progress of reaming-while-drilling efforts to date. Copyright 2013, Society of Petroleum Engineers. Source

Jimenez C.,French National Center for Scientific Research | Prigent C.,French National Center for Scientific Research | Catherinot J.,French National Center for Scientific Research | Rossow W.,City College of New York | And 2 more authors.
Journal of Geophysical Research: Atmospheres | Year: 2012

Land surface skin temperature (LST) estimates from the International Satellite Cloud Climatology Project (ISCCP) are compared with estimates from the satellite instruments AIRS and MODIS, and in situ observations from CEOP. ISCCP has generally slightly warmer nighttime LSTs compared with AIRS and MODIS (global) and CEOP (at specific sites). Differences are smaller than 2K, similar to other reported biases between satellite estimates. Larger differences are found in the day-time LSTs, especially for those regions where large LST values occur. Inspection of the AIRS and ISCCP brightness temperatures at the top of the atmosphere (TOA-BT) reveals that where the LSTs differ so too do the TOA-BT values. Area-averaged day-time TOA-BT values can differ as much as 5K in very dry regions. This could be related to differences in sensor calibration, but also to the large LST gradients at the AIRS mid-day overpass that likely amplify the impact of sensor mismatches. Part of the studied LST differences are also explained by discrepancies in the AIRS and ISCCP characterization of the surface (emissivity) and the atmosphere (water vapor). ISCCP calibration procedures are currently being revised to account better for sensor spectral response differences, and alternative atmospheric and surface data sets are being tested as part of a complete ISCCP reprocessing. This is expected to result in an improved ISCCP LST record. Copyright 2012 by the American Geophysical Union. Source

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