Basic concepts of the crystallization from aqueous solutions: The example of aluminum oxy(hydroxi)des and aluminosilicates     

Jean-Pierre Jolivet  Corinne Chanéac  David Chiche  Sophie Cassaignon  Olivier Durupthy  Julien Hernandez 《Comptes Rendus Geoscience》2011,343(2-3):113-122

This overview features the chemical background on condensation phenomena of the aluminum cation in aqueous solution. The formation of polycationic molecular clusters and nanosized solid phases of aluminum oxy(hydroxi)des is interpreted with illustrative mechanisms, building a bridge between solution chemistry and solid-state chemistry. The formation of the main structural types of aluminosilicates (zeolites, clays, imogolite) is also illustrated through the aqueous chemistry of aluminum and silicates.  相似文献   

A GIS enabled nested simulation-optimization model for routing groundwater to overcome spatio-temporal water supply and demand disconnects in South Texas     

Venkatesh Uddameri  Chandana Kakarlapudi  E. Annette Hernandez 《Environmental Earth Sciences》2014,71(6):2573-2587

Groundwater, under sustainable management policies, can be an invaluable source of water to municipal, agricultural, and industrial sectors. Management, however, can be challenging given that historically, these resources have been privately owned and minimally regulated. This research details the development of a decision support system (DSS) which couples a GIS-based multi-criteria decision-making (MCDM) scheme with simulation-optimization routines to identify suitable regions for groundwater development and optimal preferences for apportioning those supplies to areas of demand in South Texas. The developed DSS consisted of three modules: (1) a GIS-based MCDM for identifying suitable locations for groundwater production; (2) a simulation-optimization model for estimating available groundwater; and (3) a transportation optimization model for redistributing the groundwater. Applying a comprehensive suite of nine exclusionary criteria in GIS resulted in only 15,304 km² (5,909 mi²) suitable for groundwater production out of the original ~50,500 km² (19,500 mi²). Two ideal sites were selected in the suitable region based on proposed major water supply projects in the study area. The projected groundwater extraction rates per month varied considerably over a year emphasizing a need for storage technologies. Furthermore, a transportation optimization model, which considered cost of storage and movement, was developed and applied to obtain the most optimal scheme to transport groundwater from potential supply centers located in Bee and Kennedy counties to projected water deficit areas of San Antonio, Laredo, and McAllen, TX, USA. Lastly, a full-factorial sensitivity analysis was carried out to check the impacts of the supply and demand factors on groundwater production and transport. Policies at the supply centers had a larger impact on the total availability of water, and policies at the demand centers had a larger impact on the total cost of the management scheme. Furthermore, an analysis of total volume stored in a storage and recovery system exhibited an inverse relationship with the groundwater development (supply side) policies and a direct relationship with the demand requirements. The developed DSS proved useful for determining the most optimal siting and distribution network for groundwater sources in South Texas.  相似文献   

Application of geomorphologic knowledge for erosion hazard mapping     

José Alexander Chávez Hernandez  Jiři Šebesta  Lubomir Kopecky  Reynaldo López Landaverde 《Natural Hazards》2014,71(3):1323-1354

An erosion hazard map was elaborated using geomorphologic and lithological information; this was the base to characterize the erodibility of the territory. The aim of the proposed methodology is to define the areas where more detailed studies are necessary (e.g., to estimate rates of soil erosion, mitigation measurements, land use) to prevent future problems. Field work and remote sensing data (study of historical aerial photographs and satellite images) were used to understand the geomorphologic evolution and the current processes taking place in an area; this information was used to group the units according to its lithology, dynamic and slope inclination. The map was processed using the geographical information system and categorized in zones of very high, high, moderate, low and null fluvial erosion hazards. The map covers the Metropolitan Area of San Salvador, which is experiencing serious problems of mass wasting processes, collapse and settlements of foundations. Most affected areas belong to the Tierra Blanca Joven tephras which are unsaturated and cover most of the surface; nowadays, the urban projects and infrastructure resting in this material are suffering from extensive damage. The geotechnical information on the tephras shows a decrease in strength and collapsible behavior when saturated. Due to this, the use of Quickdraw tensiometers (suction) and TMS3 (soil moisture content) is proposed for monitoring. The methodology of erosion hazard mapping correlates well with mass wasting reported in the studied area, and for this reason, it could be a good way to protect the natural resources and improve the land use.  相似文献   

Dynamical consequences of CDM merger trees     

Xavier Hernandez  William H. Lee 《Monthly notices of the Royal Astronomical Society》2004,347(4):1304-1316

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GHASP: A 3-D Survey of Spiral and Irregular Galaxies at Hα     

P. Amram  C. Adami  C. Balkowski  S. Blais-Ouellette  A. Boselli  J. Boulesteix  C. Carignan  V. Cayatte  L. Chemin  J.L. Gach  O. Garrido  O. Hernandez  M. Marcelin  L. Michel-Dansac  H. Plana  D. Russeil  B. Vollmer  H. Wozniak 《Astrophysics and Space Science》2002,281(1-2):393-396

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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   

Misplaced trace fossils in unlikely environments     

Javier Ortega Hernandez 《Geology Today》2009,25(2):71-74

Graphoglyptids are trace fossils that are generally acknowledged to have had a deep-sea origin, displaying complex, nutrient gathering strategies in response to stable environments with low productivity. However, two recently discovered graphoglyptids in the Permian of New Mexico seem to challenge previous assumptions. Rather than in deep-sea sediments, Spirorhaphe azteca and Augerinoichnus helicoidalis were discovered in tidal flat palaeoenvironments, showing that these behavioural patterns are also carried out by animals in tidal settings. Fine sediments of the region are recognized as the key factor in the preservation of these trace fossils. Presence of graphoglyptids in a transitional environment demonstrates that behaviour is not solely defined by depth, but many intricate factors are involved.  相似文献   

Using Java for distributed computing in the Gaia satellite data processing     

William O’Mullane  Xavier Luri  Paul Parsons  Uwe Lammers  John Hoar  Jose Hernandez 《Experimental Astronomy》2011,31(2-3):243-258

In recent years Java has matured to a stable easy-to-use language with the flexibility of an interpreter (for reflection etc.) but the performance and type checking of a compiled language. When we started using Java for astronomical applications around 1999 they were the first of their kind in astronomy. Now a great deal of astronomy software is written in Java as are many business applications. We discuss the current environment and trends concerning the language and present an actual example of scientific use of Java for high-performance distributed computing: ESA’s mission Gaia. The Gaia scanning satellite will perform a galactic census of about 1,000 million objects in our galaxy. The Gaia community has chosen to write its processing software in Java. We explore the manifold reasons for choosing Java for this large science collaboration. Gaia processing is numerically complex but highly distributable, some parts being embarrassingly parallel. We describe the Gaia processing architecture and its realisation in Java. We delve into the astrometric solution which is the most advanced and most complex part of the processing. The Gaia simulator is also written in Java and is the most mature code in the system. This has been successfully running since about 2005 on the supercomputer “Marenostrum” in Barcelona. We relate experiences of using Java on a large shared machine. Finally we discuss Java, including some of its problems, for scientific computing.  相似文献   

Implementing the Gaia Astrometric Global Iterative Solution (AGIS) in Java     

William O’Mullane  Uwe Lammers  Lennart Lindegren  Jose Hernandez  David Hobbs 《Experimental Astronomy》2011,31(2-3):215-241

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Reply to comments by G. Gambolati and G. Galeati     

Shlomo P. Neuman  Javier Samper  Mariano Hernandez 《Mathematical Geology》1987,19(3):259-266

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