Coping with water scarcity: the case of the Calnistea catchment (Romania)     

Alina Cocos  Octavian Cocos  Ioan Sarbu 《Environmental Earth Sciences》2012,67(3):641-652

The Calnistea catchment lies in the southern part of Romania in a region that has been confronted lately with serious water scarcity problems generated primarily by summer heat waves and long periods of drought. The high temperatures, excessive evapotranspiration and scant precipitation have a negative impact on water resources and especially on the river system, which is at the mercy of meteorological conditions, because all the streams in the area originate in the plain. Consequently, mean annual discharges are very low and more often than not, many rivers run dry. In order to avoid such an unwanted phenomenon people have built earth dams across the valleys thus creating chains of ponds, which are used to regulate the flow. Even so, however, most of the years the rivers look like mere threads of water oozing gently through their sediments. Under the circumstances, it is no wonder that irrigation systems are missing, which explains the low agricultural productivity. The most important asset of the region is the groundwater, as it represents the only source of drinking water for the population. Groundwaters are stored in superposed aquifers, most of them confined, generally having good hydrogeological properties. Water quality complies with the standards for drinking water and that is why groundwaters are used as such for domestic consumption. The problem is that in the past years, population increase has put more pressure on this resource and consequently water table sank. The growing depletion of groundwaters has brought about thirst, famine, poverty and despair, sad realities that local authorities are striving to control. Given this necessity the present study aims at making several proposals of what could be done on a short and middle term in order to increase the water supplies of the region and thus alleviate the people??s suffering.  相似文献   

Classification of Tsunami and Evacuation Areas   总被引：3，自引：2，他引：1  

Tomoya Shibayama  Miguel Esteban  Ioan Nistor  Hiroshi Takagi  Nguyen Danh Thao  Ryo Matsumaru  Takahito Mikami  Rafael Aranguiz  Ravindra Jayaratne  Koichiro Ohira 《Natural Hazards》2013,67(2):365-386

On March 11, 2011, a large earthquake that occurred offshore the north-east coast of Japan generated a large tsunami which devastated extensive areas of the Tohoku coastline. Despite Japan being considered a country well prepared for these types of disasters, large casualties were recorded, with numerous discussions amongst the Japanese coastal engineering community ensuing. As a result, two different levels of tsunamis have been proposed and now recognized in Japan, depending on the frequency of such extreme events. The idea that hard measures can protect the lives of inhabitants of coastal areas has been abandoned, and these measures are only considered to be effective in protecting properties against the more frequent but lower magnitude events. Soft measures should always be used to protect against the loss of lives, and to this respect, the authors of the paper propose the introduction of a Classification of Evacuation Areas, to show which of these should be prioritized by residents as they seek to evacuate.  相似文献   

Tsunami risk for Western Canada and numerical modelling of the Cascadia fault tsunami     

Jinsong Xie  Ioan Nistor  Tad Murty 《Natural Hazards》2012,60(1):149-159

The paper deals with the analysis of tsunami risks for Western Canada and the numerical modelling of a potential tsunami which could affect the region and generate significant damage to the western Canadian coastline. Following a review of the seismic risk and historical tsunamis which occurred along the western Canadian coastline, the authors concluded that this region is highly vulnerable should a major tsunami occur. Consequently, the authors conducted a study on the numerical modelling of a possible tsunami generated by movement along the Cascadia fault, which is located offshore British Columbia. The results of the model outline the significance and extent of the coastal flooding risk associated with such a rare, but destructive phenomenon. The potential for inundation of the low-lying areas around the coastline of Vancouver Island and in and around the City of Vancouver was found to be high. A number of recommendations and conclusions focusing on the results of the numerical simulation are included.  相似文献   

A numerical analysis of the foot-floor interaction in long wall workings     

Nicolae Cristescu  Ioan R. Ionescu  I. Rosca 《国际地质力学数值与分析法杂志》1994,18(9):641-652

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Solid-liquid interfacial reaction of Zn ions on the surface of amorphous aluminosilicates with various Al/Si ratios     

Akane Miyazaki  Ioan Balint 《Geochimica et cosmochimica acta》2003,67(20):3833-3844

The adsorption behavior of Zn²⁺ ions onto the surface of amorphous aluminosilicates was studied using both potentiometric and spectroscopic methods (XANES: X-ray Absorption Near-Edge Structure). The aluminosilicates were prepared with different Al/Si ratios in order to compare the reactivities of surface aluminol and silanol groups toward Zn²⁺ ions. Potentiometric experiments were performed by maintaining the reacting suspensions at constant pH, ionic strength, and solid concentration, while Zn concentration was increased by stepwise addition. Our results showed that the surface aluminol and silanol groups possess significantly different reactivities toward Zn²⁺ ions. The reaction of Zn²⁺ ions with aluminol groups occurs through three processes: (i) surface complexation, (ii) dissolution, and (iii) re-sorption. A stoichiometric relationship was confirmed for the surface complexation between the aluminol groups and Zn²⁺ ions: two moles of H⁺ ions were released for one mole of Zn²⁺ ion adsorption. Following the surface complexation process, measurable amounts of zinc and aluminum ions were found to be mobilized from the surface of the solid to the liquid phase; subsequently, these ions precipitated on the solid surface, and possibly formed a co-precipitate with the hydrotalcite-type structure. On the other hand, a stoichiometric relationship was not obtained for the sorption of Zn²⁺ ions on silanol groups, and therefore, it was concluded that Zn²⁺ ions are retained on the surface of amorphous aluminosilicates by two different reactions. One reaction involves the surface complexation between Zn²⁺ ions and surface aluminol groups, which proceeds rapidly. The other reaction is the slow retention of Zn²⁺ ions onto silanol and/or aluminol groups, which could be the surface precipitation of Zn(OH)₂ or the co-precipitation of Zn²⁺-Al³⁺ hydroxides. It can be suggested that the total sorption behavior of Zn²⁺ ions on amorphous aluminosilicates with different Al/Si ratios can be represented as the sum of the individual reactions of Zn²⁺ ions toward the aluminol and silanol groups. The potentiometric results were confirmed by XANES data. It was clearly evident that only the aluminol groups were responsible for surface complexation of Zn²⁺ ions. An equilibrium constant was calculated for this reaction.  相似文献   

Process and signature of initiation on a finite fault system: a spectral approach     

Christophe Voisin  Michel Campillo  Ioan Ionescu  Riad Hassani  Quoc&#;Lan Nguyen 《Geophysical Journal International》2002,148(1):120-131

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Remarks on the photogravitational restricted three-body problem     

Ioan Todoran 《Astrophysics and Space Science》1993,201(2):281-285

The effects of the radiation pressure in the restricted three-body problem are considered and the existence of the out-of-plane equilibrium points is analyzed. It is found that within the framework of the stellar stability, the five Lagrangian points are the only equilibrium points, at least as far as the force of the radiation pressure is taken into account.  相似文献   

Some geographical remarks on education and prints in the languages of ethnic groups in Romania     

Mircea Buza  Ioan Ianoş 《GeoJournal》1994,34(4):457-465

The network of undergraduate schools comprises 2,336 schools and sections in towns and the countryside, especially in Transylvania, Criana, Maramure and Banat. Preschool and primary education is given in Hungarian, German, Ukrainian, Russian, Serbian, Bulgarian, Slovak, Czech, Croat, Turkish, Polish and the Gypsy languages. Secondary and high-schools function only in Hungarian, German and Serbian. Instruction in Hungarian, German, Serbian, Slovak and the Ukrainian languages is given within some sections opened at certain secondary and high-schools. Publications, however, are far more numerous — newspapers and journals, magazines and reviews are issued in sixteen languages: Hungarian, German, Gypsy, Serbian, Bulgarian, Ukrainian, Turkish, Russian, Slovak, Czech, Armenian, Yiddish, Greek, Polish, Italian and Albanian. Some of these publications are bilingual, articles being written in Romanian, too, and others only in Romanian.  相似文献   

The photogravitational restricted three-body problem     

Ioan Todoran 《Astrophysics and Space Science》1994,215(2):237-243

The photogravitational restricted three-body problem is reviewed and the case of the out-of-plane equilibrium points is analysed. It is found that, when the motion of an infinitesimal body is determined only by the gravitational forces and effects of the radiation pressure, there are no out-of-plane stable equilibrium points.  相似文献   

Post-collisional Tertiary–Quaternary mafic alkalic magmatism in the Carpathian–Pannonian region: a review     

Ioan Seghedi  Hilary Downes  Orlando Vaselli  Alexandru Szakcs  Kadosa Balogh  Zoltn Pcskay 《Tectonophysics》2004,393(1-4):43

Mafic alkalic volcanism was widespread in the Carpathian–Pannonian region (CPR) between 11 and 0.2 Ma. It followed the Miocene continental collision of the Alcapa and Tisia blocks with the European plate, as subduction-related calc-alkaline magmatism was waning. Several groups of mafic alkalic rocks from different regions within the CPR have been distinguished on the basis of ages and/or trace-element compositions. Their trace element and Sr–Nd–Pb isotope systematics are consistent with derivation from complex mantle-source regions, which included both depleted asthenosphere and metasomatized lithosphere. The mixing of DMM-HIMU-EMII mantle components within asthenosphere-derived magmas indicates variable contamination of the shallow asthenosphere and/or thermal boundary layer of the lithosphere by a HIMU-like component prior to and following the introduction of subduction components.Various mantle sources have been identified: Lower lithospheric mantle modified by several ancient asthenospheric enrichments (source A); Young asthenospheric plumes with OIB-like trace element signatures that are either isotopically enriched (source B) or variably depleted (source C); Old upper asthenosphere heterogeneously contaminated by DM-HIMU-EMII-EMI components and slightly influenced by Miocene subduction-related enrichment (source D); Old upper asthenosphere heterogeneously contaminated by DM-HIMU-EMII components and significantly influenced by Miocene subduction-related enrichment (source E). Melt generation was initiated either by: (i) finger-like young asthenospheric plumes rising to and heating up the base of the lithosphere (below the Alcapa block), or (ii) decompressional melting of old asthenosphere upwelling to replace any lower lithosphere or heating and melting former subducted slabs (the Tisia block).  相似文献