Tectonic deposition of mercury in the Almadén district,Las Cuevas deposit,Spain     

M. Jébrak  A. Hernandez 《Mineralium Deposita》1995,30(6):413-423

The Las Cuevas mercury deposit is located in the northern part of the Almadén district, Ciudad Real, Spain. It displays characteristic epigenetic features. A reinterpretation of the geological context of the deposit and a detailed structural analysis indicate that the host rocks at Las Cuevas belong to the same stratigraphic units that host the old Almadén mine, but that they experienced a different tectonic evolution. Two types of ore are distinguished at Las Cuevas: (1) hydraulic breccias in a black quartzite, identical to the San Francisco horizon of the Almadén mine. This ore has been interpreted as syngenetic and is associated with an alkaline explosive volcanic event; and (2) a stockwork composed of horizontal subcritical tension cracks which developed along the contact between black shales and volcanic rocks in the hinge of a drag fold, and which is associated with advanced argillic alteration. Mobilization of mercury from type 1 to type 2 ore was related to a local inversion of the stress field associated with an increase of permeability by self-sealing, which probably occurred during uplift. Las Cuevas is representative of a whole class of mercury deposits hosted within basement rocks.  相似文献   

Treatment of groundwater contaminated with high levels of explosives using advanced oxidation processes     

M. E. Zappi  R. Hernandez  D. Gang  R. Bajpai  C. H. Kuo  D. O. Hill 《International Journal of Environmental Science and Technology》2016,13(12):2767-2778

Current and former military installations around the world have numerous sites with groundwater contaminated with explosive compounds polluted from military related activities. The test influent used in this study was a groundwater collected from an US Army facility that was contaminated with high levels of military derived explosives. The sample had a total explosive concentration in excess of 75 mg/l. Bench-scale evaluations were performed to determine the effectiveness of the candidate advanced oxidation processes for treatment of the groundwater in terms of removing the pollutants to method sub-detection limits with these results formulating the basis for comparison along with generating data that can be used toward increasing the understanding of treatment mechanisms associated with the various processes. Results indicate that the ozonated systems generally resulted in the removal of the explosives to the targeted levels with 1,3,5-trinitrobenzene removal lagging in terms of removal due to its simultaneous formation and degradation. The oxidation system that was irradiated using the medium-pressure UV lamp and dosed with hydrogen peroxide and ozone achieved the best performance with complete removal of all targeted pollutants within 10 min of treatment.  相似文献   

Introduction     

Tony Hernandez 《The Professional geographer》2016,68(4):638-639

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Interannual-decadal variability of wintertime mixed layer depths in the North Pacific detected by an ensemble of ocean syntheses     

Toyoda  Takahiro  Fujii  Yosuke  Kuragano  Tsurane  Kosugi  Naohiro  Sasano  Daisuke  Kamachi  Masafumi  Ishikawa  Yoichi  Masuda  Shuhei  Sato  Kanako  Awaji  Toshiyuki  Hernandez  Fabrice  Ferry  Nicolas  Guinehut  Stéphanie  Martin  Matthew  Andrew Peterson  K.  Good  Simon A.  Valdivieso  Maria  Haines  Keith  Storto  Andrea  Masina  Simona  Köhl  Armin  Yin  Yonghong  Shi  Li  Alves  Oscar  Smith  Gregory  Chang  You-Soon  Vernieres  Guillaume  Wang  Xiaochun  Forget  Gael  Heimbach  Patrick  Wang  Ou  Fukumori  Ichiro  Lee  Tong  Zuo  Hao  Balmaseda  Magdalena 《Climate Dynamics》2017,49(3):891-907

Climate Dynamics - The interannual-decadal variability of the wintertime mixed layer depths (MLDs) over the North Pacific is investigated from an empirical orthogonal function (EOF) analysis of an...  相似文献   

Geotechnical zonation and soil–structure interaction at Puerto Vallarta,México     

Escudero  Christian R.  Ramirez Gaytan  Alejandro  Zamora Camacho  Araceli  Preciado  Adolfo  Flores  Karen L.  Gomez Hernandez  Adan 《Natural Hazards》2022,110(1):247-267

Natural Hazards - We performed a seismic vulnerability assessment that involves geotechnical and building structure analysis for Puerto Vallarta, Mexico, a city located along the pacific coast....  相似文献   

Energy preserving low-thrust guidance for orbit transfers in KS variables     

Sonia Hernandez  Maruthi R. Akella 《Celestial Mechanics and Dynamical Astronomy》2016,125(1):107-132

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Quantification of the Mass Flux of H2O Gas (Steam) at Three Active Volcanoes Using Thermal Infrared Imagery     

J. B. Witter  P. Hernandez  A. J. L. Harris  N. Pérez 《Pure and Applied Geophysics》2012,169(10):1875-1889

We apply a measurement technique that utilizes thermal video of vapor-dominated volcanic plumes to estimate the H₂O gas flux at three degassing volcanoes. Results are compared with H₂O flux measurements obtained using other methods to verify the thermal camera-derived values. Our estimation of the H₂O emission rate is based on the mass and energy conservation equations. H₂O flux is quantified by extracting the temperature and width of the gas plume from the thermal images, calculating the transit velocity of the gas plume from the thermal video, and combining these results with atmospheric parameters measured on-site. These data are then input into the equations for conservation of mass and energy. Selected volcanoes for this study were Villarrica in Chile, Stromboli in Italy, and Santa Ana in El Salvador. H₂O fluxes estimated from the thermal imagery were 38–250?kg?s^?1 at Villarrica, 4.5–14?kg?s^?1 for Stromboli’s Central Crater, and 168–219?kg?s^?1 at Santa Ana. These compare with H₂O flux values estimated by other methods of 73–220, 3–70 and 266?kg?s^?1, at the three volcanoes, respectively. The good agreement between thermal image-derived results and those estimated by other methods seem to validate this method.  相似文献   

Objective Determination of Star Formation Histories     

G. Gilmore  X. Hernandez  D. Valls-Gabaud 《Astrophysics and Space Science》2000,272(1-3):61-72

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Decomposition algorithms for system reliability estimation with applications to interdependent lifeline networks          下载免费PDF全文

Roger Paredes  Leonardo Dueñas‐Osorio  Isaac Hernandez‐Fajardo 《地震工程与结构动力学》2018,47(13):2581-2600

Reliability and risk assessment of lifeline systems call for efficient methods that integrate hazard and interdependencies. Such methods are computationally challenged when the probabilistic response of systems is tied to multiple events, as performance quantification requires a large catalog of ground motions. Available methods to address this issue use catalog reductions and importance sampling. However, besides comparisons against baseline Monte Carlo trials in select cases, there is no guarantee that such methods will perform or scale well in practice. This paper proposes a new efficient method for reliability assessment of interdependent lifeline systems, termed RAILS, that considers systemic performance and is particularly effective when dealing with large catalogs of events. RAILS uses the state‐space partition method to estimate systemic reliability with theoretical bounds and, for the first time, supports cyclic interdependencies among lifeline systems. Recycling computations across an entire seismic catalog with RAILS considerably reduces the number of system performance evaluations in seismic performance studies. Also, when performance estimate bounds are not tight, we adopt an importance and stratified sampling method that in our computational experiments is various orders of magnitude more efficient than crude Monte Carlo. We assess the efficiency of RAILS using synthetic networks and illustrate its application to quantify the seismic risk of realistic yet streamlined systems hypothetically located in the San Francisco Bay Region.  相似文献   

Using multinomial models to analyse data from Iberian sardine egg incubation experiments: a comparison with traditional techniques     

Bernal  Miguel; Ibaibarriaga  Leire; Lago de Lanzos  Ana; Lonergan  Mike E.; Hernandez  Carmen; Franco  Concha; Rasines  Inmaculada; Valdes  Luis; Borchers  David L. 《ICES Journal of Marine Science》2008,65(1):51-59

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