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1
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Chislovoj metod opredelenija naprjazhenno-deformirovannogo sostojanija i kriticheskikh nagruzok poteri ustojjchivosti arok

100%
Shebanin V., Bogza V., Bogdanov S., Hilko I.
Motrol. Motoryzacja i Energetyka Rolnictwa
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2013
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tom 15
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nr 2
2

Inorganic pollutants deposition in Gdansk Region in relation to the critical load concept

100%
Medrzycka K. B., Landowska A.
Polish Journal of Environmental Studies
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2002
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tom 11
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nr 6
The deposition of acidifying compounds in Gdask region has been investigated. Bulk wet (in the open field), and through­fall (in the forest) stand, depositions were measured from 1994 till 2001. The deposition of sul­phates, nitrates and ammonium salts has been analysed. The obtained results are compared with the critical depo­sition for sulphur and nitrogen related to the Gdask region. It has been stated that exceeding critical load was not observed for sulphur, while it was ob­served for nitrogen.
3
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The Engesser-Shanley modified theory of stability of thin-walled cylindrical rods with example of use for steel ST 35

100%
Murawski K.
Acta Scientiarum Polonorum. Architectura
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2002
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tom 01
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nr 1-2
4
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Chemical criteria in the critical loads concept

84%
Mill W.
Zeszyty Problemowe Postępów Nauk Rolniczych
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2002
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tom 481
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nr 1
The critical loads concept has been developed under the Convention on Long-Range Transboundary Air Pollution as a scientific basis for the negotiations of its environmentally effect-oriented protocols. The basic idea of this concept is to balance the atmospheric depositions which a given ecosystem is exposed to with the capacity of this ecosystem to buffer the input in the system. Accordingly, a critical loads approach to control acidic emissions in relation to their ecological effects has been introduced. Critical load is defined as "a quantitative estimate of an exposure to one or more pollutants below which significant harmful effects on specified sensitive elements of the environment do not occur according to present knowledge". In this study, the critical loads approach has been applied to the problem of forest ecosystem acidification resulting from sulfur and nitrogen emission. There are several criteria that may be used as critical chemical limits in forest soil solution. These are critical pH, critical Al concentration, critical BC/A1 ratio and Al depletion criterion. The reliability of the calculated critical loads is strongly influenced by the quality of the chemical criteria applied. For abiotic aspects like soil chemistry or ground water quality the critical limits are clear because the dose-effect relations are quite well understood. For biotic indicators like root damage it is more difficult to find critical limits which can be used as threshold levels below which effects are negligible. The process of root damage is quite a complex one and a combination of side factors like droughts and adverse soil chemical condition may contribute to it. So, when a single critical limit such as the ВС/Al ratio is used, this will inherently lead to a considerable uncertainty in the value of this critical limit. Critical limits are based on laboratory experiments during a limited period of time in which sample roots are subject to constantly elevated BC/A1 ratios. One of major problems in applying this kind of criteria is the interpretation of the laboratory bioassay results in relation to field conditions. The aim of this paper is to summarize the current knowledge and to formulate the major questions that should be answered to abate the existing uncertainty in relating the anthropogenically modified soil chemistry and the reaction of forest ecosystems.
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