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Effects of humic acid transport and transformation of mercury in soil-plant systems
1997
Wang, D.Y. (Southwest Agricultural Univ., Chongqing (China). Coll. of Resources and Environment) | Qing, C.L. | Guo, T.Y. | Guo, Y.J.
Needle S fractions and S to N ratios as indices of SO(2) deposition
1997
Manninen, S. (Oulu Univ. (Finland). Dept. of Biology and Botany) | Huttunen, S. | Peraemaeki, P.
Metal-metal interactions in biological systems. Part 4. Steinernema carpocapsae (Steinernematidae) and Heterorhabditis bacteriophora (Heterorhabditidae) entomopathogenic nematodes
1997
Jaworska, M. (Hugon Kollataj Academy of Agriculture, Cracow (Poland). Dept. of Entomology) | Gorczyca, A. | Sepiol, J. | Szeliga, E. | Tomasik, P.
Soil lead levels in orchards and roadsides of mission Peninsula, Michigan
1997
Francek, M.A. (Central Michigan Univ., Mt. Pleasant, MI (USA). Dept. of Geography and Earth Science)
Principal forest dieback episodes in Northern Hardwoods: development of numeric indices of areal extent and severity
1997
Auclair, A.N.D. (Science and Policy Associates Inc., Washington, DC (USA).) | Eglinton, P.D. | Minnemeyer, S.L.
Rhizosphere microbial populations in contaminated soils
1997
Nichols, T.D. (Arkansas Univ., Fayetteville, AR (USA). Dept. of Agronomy) | Wolf, D.C. | Rogers, H.B. | Beyrouty, C.A. | Reynolds, C.M.
Substance flows through the economy and environment of a region : Part I: Systems definition(ESPR 2 (2) 90–96 (1995) Part II: Modelling(ESPR 2 (3) 137–144 (1995)
1997
van der Voet, Ester | Kleijn, René | van Oers, Lauran | Heijungs, Reinout | Huele, Ruben | Mulder, Paul
In the tradition of the study of materials flows through society, the Substance Flow Analysis (SFA) method is presented. SFA aims at providing the relevant information for a country’s overall management strategy regarding single substances or coherent groups of substances. This article is dedicated to the presentation of a threestep general framework for SFA-type studies, and elaborates on its first step the systems definition. Attention is given to the definition of the external and internal system boundaries, the categorization of the system’s elements, aspects of materials choice, time, and space, and how these depend on the aim of the conducted study. Moreover, a broader discussion is started on the need for standardization of materials flow studies in general.In the tradition of the study of materials flows through society, the Substance Flow Analysis (SFA) method and its software tool SFINX are presented. SFA aims at providing the relevant information for a country’s overall management strategy regarding single substances or coherent groups of substances. Three modelling techniques and their possibilities and limitations are discussed: Bookkeeping, static modelling, and dynamic modelling. The computer program SFINX can be used for varoius purposes: (1) to obtain an overview of stocks and flows of a substance in, out and through a nation’s economy and environment for a specific year, (2) to trace the origins of specific pollution problems, and (3) to estimate the effectiveness of certain abatement measures. Each application has its own requirements with regard to data and modelling.
Afficher plus [+] Moins [-]Phase equilibria of vegetable oils with near-critical fluids
1997
Fuente B, J.C de la | Fornari, T. | Brignole, E.A. | Bottini, S.B.
The application of the SRK equation of state for the prediction of the phase behaviour of mixtures of vegetable oils with near critical solvents is studied. The use of binary interaction parameters in the combinatorial rules for both the co-volume and the energy parameter is discussed. Two different sets of binary interaction parameters are needed in order to correlate the vapor-liquid and liquid-liquid equilibria. This indicates a serious limitation of van der Waals type of equations of state for modeling the phase equilibria of this type of systems.
Afficher plus [+] Moins [-]Supercritical carbon dioxide extraction of volatile compounds from rosemary
1997
Coelho, J.A.P. | Mendes, R.L. | Provost, M.C. | Cabral, J.M.S. | Novais, J.M. | Palavra, A.M.F.
Supercritical CO2 extraction of oleoresin from portuguese rosemary (Rosmarinus officinalis L.) was carried out with a flow apparatus at temperatures of 35 and 40 degrees C and pressures of 100, 125 and 200 bar. The highest fraction of volatile compounds (oil) in the oleoresin was obtained at 100 bar and 40 degrees C. An unsteady mathematical model was able to give good representation of the supercritical extraction curves and a mass transfer coefficient was determined using the successive quadratic programming method. Values of this coefficient ranged between 4.49 and 15.07 kg/m3s and the shift to a diffusion-controlled regime occurred when 44% of the total oil was extracted.
Afficher plus [+] Moins [-]Pollution prevention in the paints and coatings industry
1997
Joseph, Ron