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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Acta mathematica hungarica 76 (1997), S. 235-247 
    ISSN: 1588-2632
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-0867
    Keywords: agricultural residues ; cotton ; fibre quality ; vinasse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A concentrated depotassified beet vinasse was mixed with each of ten solid agricultural residues. The ten mixtures were composted for 7 months. The composts obtained after this period were used to fertilize a cotton crop. A mineral treatment was used for comparison and a treatment without fertilization was used as control. The nitrate content of petiole determined before the first top dressing revealed significant differences between treatments. All treatments produced higher yields than the control. Analysis of fibre quality did not show significant differences between treatments.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1573-5036
    Keywords: drip irrigation ; olive root ; root activity ; root distribution ; soil moisture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A study was carried out on the root distribution and root activity of the olive tree (Olea Europaea, L., var. manzanillo) as influenced by drip irrigation and by several soil characteristics such as texture and depth. The experiments were conducted in two plots within a drip-irrigated grove of 20-year-old trees planted at 7×7 m spacing. One soil was a sandy loam, the other a clay-loam. Both cylinder and trench methods were used to determine root distribution. Labelling with 32P was used to determine root activity. Under dryland conditions the adult tree adapted its rooting system, following the installation of a drip system, by concentrating the roots within the wet soil zones near the drippers. The highest root densities occur in those zones, down to a 0.6 m depth, the most abundant being the 〈0.5 mm diameter roots. The most intensive root activity was also found in that zone. For a given irrigation system, wet soil bulbs are more extensive and therefore root distribution expands to a larger soil volume when the soil is more clayey and with a hard calcareous pan present at about 0.8 m depth which prevents deep drainage.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1359-5997
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Description / Table of Contents: Resume On examine les problèmes relatifs à la signification du contrôle expérimental de la déformabilité de structures précontraintes de vaste portée soumises à des chargements de courte durée afin de tirer des conclusions sûres sur leur comportement statique. On souligne la nécessité, dans ce but, d'une évaluation exacte du module élastique du béton, en même temps que l'importance de sa mesure expérimentale, qui est trop peu précise si on la déduit de la résistance du béton. Ce travail montre aussi comment, en réduisant l'incertitude dans le calcul du fléchissement, la mesure directe du module sur le béton de la structure (et pas seulement sur des éprouvettes coulées pendant la construction) améliore la sûreté de l'évaluation de la bonne statique de la construction et la justesse de son modèle. A ce propos, la méthode ultrasonique peut se révéler très utile. Toutefois, nous avons montré qu'elle peut donner de mauvais résultats—en particulier quand l'essai de charge est effectué longtemps après les moulages—si nous n'effectuons pas les corrections qui conviennent afin de tenir compte de l'évolution dans le temps de la corrélation entre le module statique et dynamique, alors que cet aspect est d'habitude négligé.
    Notes: Abstract The problems in giving significance to the experimental control of deformability at short-term loadings of large-span prestressed structures in order to draw reliable conclusions on their static behaviour have been examined. With this aim the necessity of an exact evaluation of the elastic modulus of concrete together with the importance of its experimental measurement, which is too imprecise if deduced from the strength of concrete, have been pointed out. The work also shows how, by reducing uncertainty in calculating deflection, modulus measurement directly on the structure's concrete (and not only on specimens cast during construction) improves reliability in the evaluation of the static validity of the construction and the exactness of its modelling. In this regard the ultrasonic method can prove very useful. However, we have shown that it can give wrong results—especially when the load test is carried out long after the casting—if we do not make suitable corrections to take into account the evolution with time of the correlation between static and dynamic moduli, an aspect that is usually neglected.
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  • 5
    ISSN: 1432-1319
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A field experiment was conducted to examine the effect of drip irrigation using wastewater from a table olive industry on physiological, nutritional and yield parameters of olive trees (Olea europaea L.). Very limited information, if any, exists, on the potential of recycling this kind of wastewater in agriculture. Two types of wastewater were used in the experiment, the first with SAR and EC values of 12–56 and 3.5–4.2 dS m−1, respectively, and the second 73–90 and 4.3–6.0 dS m−1. In general, this kind of wastewater has a highly variable composition and SAR values that are too high for agricultural purposes. Olive trees rapidly responded to wastewater application. Compared to the control (fresh water), the more saline wastewater caused important decreases in leaf water potential, stomatal conductance to H2O and the photosynthesis rate after only 15 days of irrigation, the reduction being more pronounced after 2 months of irrigation. This treatment also caused a rapid, significant reduction in leaf N concentration, as compared with the N level in the trees before irrigation. Both types of wastewater significantly reduced olive yield, compared to that obtained in the control. These results indicate that this kind of wastewater is unsuitable for application to olive orchards under irrigation.
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    ISSN: 1365-2389
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: For the survey of saline and alkali soils sampling soil solution in situ is difficult. An alternative is to take soil samples, analyse their extracts and then calculate the chemical composition of the soil solution. A model (EXPRESO) has been designed to calculate both the chemical speciation of electrolyte solution and the exchange equilibrium with an adsorbed phase during simulated dilution and concentration. EXPRESO was validated using reclaimed saline soil samples. Results demonstrated that EXPRESO is a thermodynamically coherent and mass conservative model that allows the calculation of the chemical composition of both the soil solution and the exchange complex over a large range of soil water content (0.250–5 kg water kg–1 soil). EXPRESO enables the estimation of the chemical composition of the in situ soil solution, giving a comprehensive picture of the soil status under different field conditions. Modélisation de la concentration ou de la dilution des systèmes eau-sols salés Résumé
    Type of Medium: Electronic Resource
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  • 7
    Publication Date: 1997-01-01
    Description: The theoretical and experimental investigation of a cable-stayed bridge after major repair is described in this paper. Strengthening mainly involved the suspension system (originally with prestressed concrete stays) which was retrofitted by means of external tendons. Full-scale tests were conducted to measure the dynamic response of the repaired system; the experimental program included both traffic-induced and free vibration measurements. A total of 16 vertical frequencies and mode shapes were identified in the frequency range of 0-10 Hz. In the theoretical study, vibration modes involving deck, towers and cables were determined by using finite element models which accounted for the strengthening effects. Two- and three-dimensional models were used so that the importance of three-dimensional modes was estimated as well. The experimental results were compared to natural frequencies and mode shapes computed using theoretical models. For most modes the measured and predicted modal parameters compare well, especially for the vertical modes involving in-phase motion of the stays.
    Print ISSN: 0098-8847
    Electronic ISSN: 1096-9845
    Topics: Architecture, Civil Engineering, Surveying
    Published by Wiley
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  • 8
    Publication Date: 2003-12-19
    Description: The dynamic behaviour of two curved cable-stayed bridges, recently constructed in northern Italy, has been investigated by full-scale testing and theoretical models. Two different excitation techniques were employed in the dynamic tests: traffic-induced ambient vibrations and free vibrations. Since the modal behaviour identified from the two types of test are very well correlated and a greater number of normal modes was detected during ambient vibration tests, the validity of the ambient vibration survey is assessed in view of future monitoring. For both bridges, 11 vibration modes were identified in the frequency range of 0-10Hz, being a one-to-one correspondence between the observed modes of the two bridges. Successively, the information obtained from the field tests was used to validate and improve 3D finite elements so that the dynamic performance of the two systems were assessed and compared based on both the experimental results and the updated theoretical models. © 2003 John Wiley and Sons, Ltd.
    Print ISSN: 0098-8847
    Electronic ISSN: 1096-9845
    Topics: Architecture, Civil Engineering, Surveying
    Published by Wiley
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  • 9
    Publication Date: 1978-01-01
    Print ISSN: 0009-8604
    Electronic ISSN: 1552-8367
    Topics: Geosciences
    Published by Clay Minerals Society
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  • 10
    Publication Date: 1979-01-01
    Print ISSN: 0009-8604
    Electronic ISSN: 1552-8367
    Topics: Geosciences
    Published by Clay Minerals Society
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