Water use by intensively cultivated willow using estimated stomatal parameter values     

Harald Grip  Sven Halldin  Anders Lindroth 《水文研究》1989,3(1):51-63

Large land areas in Sweden are planned to be planted with high producing, short rotation forest stands of willow in the beginning of the 1990s. Since willow is a highly hydrophilic species, this new land use may have strong implications on water resources. To assess these implications, evaporation of Salix viminalis and Salix viminalis x caprea stands in lysimeters was analysed with the simple, yet physically realistic KAUSHA model. Parameter values for the Lohammar equation were deduced (b = 100 m³ kg^?1, k_max = 0.01 m s^?1), believed to be applicable to other sites. Simulated evaporation during the 1980 growth season for a normal stand with a production of 12 tonnes of dry matter per hectare per season was 526 mm, of which 375 mm was transpiration, 56 mm interception evaporation, and 95 mm soil evaporation. For an optimally irrigated 20-tonnes stand, the total evaporation was 584 mm, of which 430 mm was transpiration. As a comparison, Penman open water evaporation was 430 mm. To avoid soil water stress in the 20-tonnes stand, 140 mm was needed as irrigation, equivalent to 25 per cent of the mean annual precipitation. Since intensively cultivated willow plantations seemed to be using much water, it was concluded that introduction of this agri-forestry practice must be carefully planned to make use of this property, e.g. in biological filters or in reclaiming water-logged land.  相似文献   

Some aspects of coupled febem analysis of underground openings     

G. Beer  A. Varadarajan 《国际地质力学数值与分析法杂志》1987,11(2):215-217

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Avalanche Hazard Mitigation Strategies Assessed by Cost Effectiveness Analyses and Cost Benefit Analyses—evidence from Davos,Switzerland     

Sven Fuchs  Magdalena Thöni  Maria Christina McAlpin  Urs Gruber  Michael Bründl 《Natural Hazards》2007,41(1):113-129

This paper demonstrates the application of cost effectiveness analysis and cost benefit analysis to alternative avalanche risk reduction strategies in Davos, Switzerland. The advantages as well as limitations of such analysis for natural hazards planning are discussed with respect to 16 avalanche risk reduction strategies. Scenarios include risk reduction measures that represent the main approaches to natural hazards planning in Switzerland, such as technical, organisational, and land use planning measures. The methodologies used outline how concepts and techniques from risk analysis, hazard mapping, Geographic Information System, and economics can be interdisciplinary combined. The results suggest important considerations, such as possible sources of uncertainty due to different choices in the calculation of cost effectiveness ratio and net present value. Given the parameters and assumptions, it seems as if the current approach to avalanche risk reduction in the study area approximates to economic and cost efficiency and serves the aim of reducing risk to human fatalities.  相似文献   

Discussion of “The effect of weathering on pore geometry and compressive strength of selected rock types from Turkey” by Tuğrul, Engineering Geology, 75: 215–227 (2004)     

Sven ke Larson  Eva-Lena Tullborg 《Engineering Geology》2006,82(4):268-269

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A device for rapid sectioning of soft bottom sediment cores   总被引：1，自引：0，他引：1  

Sven Blomqvist  Berndt Abrahamsson 《Aquatic Sciences - Research Across Boundaries》1987,49(3):393-396

A new mechanical sectioning device for transverse cutting of cylindrical soft bottom sediment cores is presented. The instrument is rapid and efficient in use, works serially when sectioning a core and permits rinsing of the sample compartment without removal from the coring tube. The device is made of plastic, is lightweight, convenient to operate even in the field and simple and cheap to manufacture.  相似文献   

Petrogenesis of Archaean Tonalites     

Prof. Dr. Sven Maaløe 《International Journal of Earth Sciences》1982,71(1):328-346

The Archean tonalitic magma series is characterized by a high Al₂O₃ and Na₂O content. Tertiary tonalites with similar major element composition have been generated in subduction zones. It is therefore suggested that the Archean tonalites was generated in relation to subduction zones, the primary magma of the series being of dioritic composition. The generation of the primary magma occurred at about 15 kbar, while the recent generation of andesite occur at about 30 kbar. The higher frequency of generation in the Archean, and the relatively small depth of geneeration is related to the slightly higher temperatures of the mantle in the Archean.

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Zusammenfassung Die tonalitische Magmenfolge des Archäikum wird durch hohe Al₂O₃- und Na₂O-Gehalte gekennzeichnet. Tertiäraltrige Tonalite mit ähnlicher Hauptelement-Zusammensetzung entstanden in Subduktionszonen. Deshalb wird vorgeschlagen, daß die archäischen Tonalite im Zusammenhang mit Subduktionszonen entstanden, wobei das primäre Magma der Folge dioritischer Zusammensetzung war. Das primäre Magma entstand unter einem Druck von etwa 15 kbar; in jüngster Zeit entsteht aber Andesit bei etwa 30 kbar. Die höhere Entstehungsrate im Archäikum wird, so wie auch die verhältnismäßig geringe Entstehungstiefe, zu den etwas höheren Manteltemperaturen im Archäikum in Beziehung gesetzt.

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Résumé La série des magmas tonalitiques de l'Archéen est caractérisée par une haute teneur en Al₂O₃. Les tonalites tertiaires, de même composition quant aux éléments majeurs, ont été engendrées dans des zones de subduction. C'est pourquoi il est suggéré que les tonalites archéennes aient été engendrées en relation avec des zones de subduction, le magma primaire de la série étant de composition dioritique. La genèse du magma primaire se fit sous environ 15 kbar, tandis que la genèse récente des andésites se fait à 30 kbar. La fréquence élevée de la formation dans l'Archéen et la profondeur relativement faible de cette formation est en liaison avec les températures légèrement plus élevées du manteau dans l'Archéen.

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The chemistry of geothermal waters in Iceland. I. Calculation of aqueous speciation from 0° to 370°C     

Stefán Arnórsson  Sven Sigurdsson  Hördur Svavarsson 《Geochimica et cosmochimica acta》1982,46(9):1513-1532

A computer programme has been developed to calculate the composition and aqueous speciation of geothermal reservoir waters including pH, redox potential and gas partial pressures. The programme is specifically suited to handle geochemical data from wet-steam wells, hot-water wells and boiling hot springs, but it may also be used for non-thermal waters. Solubility data for selected geothermal minerals are incorporated to facilitate the study of $\text{solution}\text{mineral}$ equilibria. The programme may also be used to study chemical changes in water chemistry accompanying boiling, variable degassing and cooling, and how these changes disturb $\text{solution}\text{mineral}$ equilibria.  相似文献   

Improving the performance of genetic algorithms for land-use allocation problems     

Jonas Schwaab  Kalyanmoy Deb  Erik Goodman  Sven Lautenbach  Maarten J. van Strien  Adrienne Grêt-Regamey 《International journal of geographical information science》2018,32(5):907-930

Multi-objective optimization can be used to solve land-use allocation problems involving multiple conflicting objectives. In this paper, we show how genetic algorithms can be improved in order to effectively and efficiently solve multi-objective land-use allocation problems. Our focus lies on improving crossover and mutation operators of the genetic algorithms. We tested a range of different approaches either based on the literature or proposed for the first time. We applied them to a land-use allocation problem in Switzerland including two conflicting objectives: ensuring compact urban development and reducing the loss of agricultural productivity. We compared all approaches by calculating hypervolumes and by analysing the spread of the produced non-dominated fronts. Our results suggest that a combination of different mutation operators, of which at least one includes spatial heuristics, can help to find well-distributed fronts of non-dominated solutions. The tested modified crossover operators did not significantly improve the results. These findings provide a benchmark for multi-objective optimization of land-use allocation problems with promising prospectives for solving complex spatial planning problems.  相似文献   

Assessing hydrological changes in a regulated river system over the last 90 years in Rimac Basin (Peru)     

Vega-Jácome  Fiorella  Lavado-Casimiro  Waldo Sven  Felipe-Obando  Oscar Gustavo 《Theoretical and Applied Climatology》2018,132(1-2):347-362

Theoretical and Applied Climatology - Hydrological changes were assessed considering possible changes in precipitation and regulation or hydraulic diversion projects developed in the basin since...  相似文献   

Response to: “Critical Analysis of a Hypothesis of the Planetary Tidal Influence on Solar Activity” by S. Poluianov and I. Usoskin     

J. A. Abreu  C. Albert  J. Beer  A. Ferriz-Mas  K. G. McCracken  F. Steinhilber 《Solar physics》2014,289(6):2343-2344

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