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81.
E. Vaccaro P. Wozniakiewicz I. A. Franchi N. Starkey S. S. Russell 《Meteoritics & planetary science》2023,58(5):688-704
The matrix of primitive chondrites is composed of submicron crystals embedded in amorphous silicates. These grains are thought to be the remains of relatively unprocessed dust from the inner regions of the protoplanetary disk. The matrix of primitive meteorites is often compared to chondritic porous interplanetary dust particles (CP-IDPs) which are believed to be of cometary origin, having accreted in the outermost regions of the solar nebula. Crystalline grains in CP-IDPs show evidence of a size–density relationship between the silicates and sulfides suggesting that these components experienced sorting prior to accretion. Here, we investigate whether such evidence of sorting is also present in the matrix constituents of primitive chondrites. We report findings from our study of grain size distributions of discrete silicate and opaque (sulfide and metal) grains within the matrix of the primitive meteorites Acfer 094 (C2-ung.), ALHA77307 (CO3), MIL 07687 (C3-ung.), and QUE 99177 (CR2). Mean radii of matrix silicate grains range from 103 nm in QUE 99177 to 2018 nm in MIL 07687. The opaque grains show a wider variation, with average radii ranging from 15 nm in QUE 99177 to 219 nm in MIL07687. Our results indicate that, in contrast to CP-IDPs, the size distribution of matrix components of these primitive meteorites cannot be explained by aerodynamic sorting that took place prior to accretion. We conclude that any evidence of sorting is likely to have been lost due to a greater variety and degree of processing experienced on these primitive chondrites than on cometary parent bodies. 相似文献
82.
Hsiao-Chung Tsai Russell L. Elsberry 《Asia-Pacific Journal of Atmospheric Sciences》2014,50(4):507-518
A version of our situation-dependent intensity prediction (SDIP) is proposed for operational application after three modifications: (i) Ten historical track analogs are matched with Joint Typhoon Warning Center (JTWC) official track forecasts rather than besttracks; (ii) Giving two times as much weight to the 72 h — 120 h portion of the track as to the 0–72 h portion to give higher rankings for analog tracks with similar landfall or recurvature positions and timing; and (iii) Weighting both the intensity prediction technique and a new intensity spread guidance product according to new rankings of the track analogs rather than assuming all track analogs are equally likely. These special matchings and weightings of the track analogs in this weighted-analog intensity (WANI) add skill in the 72–120 h forecast intervals in regions where landfalls occur. Viability as an operational technique is demonstrated as the WANI has only 1 kt larger mean absolute errors than the JTWC intensity errors from 12 h through 72 h, and the WANI is 5 kt (20%) better at 120 h. The WANI rank-weighted intensity spreads each 12 h among the 10 best historical track analogs are processed to reduce any intensity bias and calibrated to reduce (increase) the over-determined (under-determined) intensity spreads at early (later) forecast intervals. Thus, the situation-dependent intensity spread guidance is generated that will include about 68% of the verifying intensities at all forecast intervals. Four examples of the WANI intensity predictions and intensity spread guidance are presented to illustrate how the forecaster might use this information in potential landfall and intensity bifurcation situations. 相似文献
83.
Joel W. Feldmeier Wendell A. Nuss Russell L. Elsberry 《Asia-Pacific Journal of Atmospheric Sciences》2014,50(4):459-468
Although the Sasebo, Japan harbor is usually a “typhoon haven” from tropical cyclone (TC) winds due to terrain-blocking effects, in rare cases damaging winds occur that may be attributed to terrain channeling. An empirical parametric model technique is developed and tested that includes consideration of the TC wind structure, land frictional effects, and terrain influences affecting the maximum wind speeds in the harbor when TCs pass within 200 nautical miles of Sasebo. The terrain influence is represented by two sets of wind direction-dependent acceleration factors. The first set, which is directly from the ratio of the local wind to the adjusted parametric wind for TCs passages during 2003–2010, provides mean values that represent the terrain blocking and channeling effects, but the variability with wind direction may be suspect. The second set derived from a large sample of reanalysis winds not limited to TCs has better variability properties, but is not easily related to just the TC passages. A new nomogram modified to include TC wind structure has higher estimates of Sasebo sustained winds for some TC tracks that may be related to terrain influences, but is limited due to the number of TC structure estimates in the developmental sample. These empirical models have the advantage of ease and low cost for future use in also estimating the combined uncertainty in the local winds in Sasebo harbor due to TCs. 相似文献
84.
Liaqat Ali Russell E. Bentley Alberto A. Gutierrez Yosmar Gonzalez 《Acta Geotechnica》2014,9(1):135-144
The use of slickline distributed temperature sensing (SL-DTS) technology is becoming widespread due to its ease of operation and ability to acquire real-time multiple temperature traces inside the wellbore. Injection of treated acid gas (TAG)—a mixture of CO2 and H2S—into geologic formations has become an attractive technical and economic option for oil and gas producers and processors who are faced with regulations concerning excess sulfur and greenhouse gas emissions. Acid gas injection (AGI) into geologic formations is more economical and more flexible in dealing with varying TAG compositions than sulfur recovery units (SRUs) using the Claus process. SRUs do not achieve air quality standards and have high operation and maintenance costs. In addition, there is low demand for sulfur and sulfur disposal costs are high. The results of the analysis of SL-DTS data acquired in conjunction with step rate and pressure falloff (PFO) tests are presented in this paper. These tests were conducted to evaluate the injection potential of geologic formations. The injection zone consisted of a carbonate formation characterized by Karst features, vugs, and natural fractures. The SL-DTS data during the initial injection flow rate for the step rate test (SRT) indicated that high permeability zones accepted fluid at lower injection rates. An increasing number of discrete zones began to accept fluid as the injection rate was increased. The results of the SRT provided the fracture pressure of the formation. This information was used to design an AGI program that would avoid fracturing the formation while allowing for the required volume of TAG to be injected. The results of the PFO test provided information on the reservoir pressure and permeability and also indicated the presence of one or more hydraulic fractures. This case study of SL-DTS measurements made during a SRT and a PFO test for the design of an AGI well provides valuable insights into the potential of DTS technology and its use in AGI and carbon capture/sequestration (CCS) operations. Its findings could be applied to analyze injection potential of geological formations not only for AGI projects but also for CCS, and CO2 enhanced oil recovery opportunities. 相似文献
85.
Manuela Magliocchetti Steve J. Maddox Ed Hawkins John A. Peacock Joss Bland-Hawthorn Terry Bridges Russell Cannon Shaun Cole Matthew Colless Chris Collins Warrick Couch Gavin Dalton Roberto de Propris Simon P. Driver George Efstathiou Richard S. Ellis Carlos S. Frenk Karl Glazebrook Carole A. Jackson Bryn Jones Ofer Lahav Ian Lewis Stuart Lumsden Peder Norberg Bruce A. Peterson Will Sutherland Keith Taylor 《Monthly notices of the Royal Astronomical Society》2004,350(4):1485-1494
86.
Douglas S. Hall Gregory W. Henry Dietmar Böhme Peter A. Brooks Sandy Chang Ales Dolzan George L. Fortier Robert E. Fried Russell M. Genet Bruce S. Grim James Hannon Darrel B. Hoff Kevin Krisciunas Howard J. Landis Howard P. Louth Larry P. Lovell Paul Nielsen Bobby E. Powell Harry D. Powell Don Pray Thomas R. Renner Charles W. Rogers Stephen Shervais Douglas M. Slauson Samuel Slote Harold J. Stelzer Arthur J. Stokes Jack C. Troeger Louis C. Turner Norman F. Wasson Kenneth W. Zeigler 《Journal of Astrophysics and Astronomy》1991,12(4):281-287
We present photoelectric photometry of λ And never before published, obtained between February 1982 and December 1990 at 29
different observatories. Then we combine it with all other photometry available to us (previously published, contained in
the I.A.U. Commission 27 Archives, and obtained with the Vanderbilt 16-inch automatic telescope but not yet published), to
yield a 14.8-year data base. Analysis reveals a long-term cycle in mean brightness, with a full range of 0m.15 and a period of 11.4 ± 0.4 years. Because most of our new photometry was concentrated in the 1983-84 observing season,
we analyze that one well-defined light curve with a two-spot model. Spot A keeps a 0m.04 amplitude throughout four rotation cycles whereas the amplitude of spot B diminishes from 0m.09 down almost to 0m.03. The spot rotation periods were 55d.9 ± 0d.6 and 520d.8 ± 1d.0, respectively. 相似文献
87.
Howell G.M. Edwards Caroline D. Moody Susana E. Jorge Villar Michael J. Russell 《Icarus》2005,175(2):372-381
Raman spectra of an extremophile cyanobacterial colony in hydromagnesite from Lake Salda in Turkey have revealed a biogeological modification which is manifest as aragonite in the stratum associated with the colony. The presence of key spectral biomarkers of organic protectant molecules such as β-carotene and scytonemin indicate that the survival strategy of the cyanobacteria is significantly one of UV-radiation protection. The terrestrial location of this extremophile is worthy of consideration further because of its possible putative link with the “White Rock” formations in Sabaea Terra and Juventae Chasma on Mars. 相似文献
88.
D. Heath Jones Will Saunders Matthew Colless Mike A. Read Quentin A. Parker Fred G. Watson Lachlan A. Campbell Daniel Burkey Thomas Mauch Lesa Moore Malcolm Hartley Paul Cass Dionne James Ken Russell Kristin Fiegert John Dawe John Huchra Tom Jarrett Ofer Lahav John Lucey Gary A. Mamon Dominique Proust Elaine M. Sadler Ken-ichi Wakamatsu 《Monthly notices of the Royal Astronomical Society》2004,355(3):747-763
89.
90.
The 2dF Galaxy Redshift Survey: the bJ -band galaxy luminosity function and survey selection function
Peder Norberg Shaun Cole Carlton M. Baugh Carlos S. Frenk Ivan Baldry Joss Bland-Hawthorn Terry Bridges Russell Cannon Matthew Colless Chris Collins Warrick Couch Nicholas J. G. Cross Gavin Dalton Roberto De Propris Simon P. Driver George Efstathiou Richard S. Ellis Karl Glazebrook Carole Jackson Ofer Lahav Ian Lewis Stuart Lumsden Steve Maddox Darren Madgwick John A. Peacock Bruce A. Peterson Will Sutherland Keith Taylor 《Monthly notices of the Royal Astronomical Society》2002,336(3):907-931