scholarly journals Mean residence time concepts for non-linear pharmacokinetic systems

1994 ◽  
Vol 15 (8) ◽  
pp. 627-641 ◽  
Author(s):  
Haiyung Cheng ◽  
William R. Gillespie ◽  
William J. Jusko
Keyword(s):  
Residence Time ◽  
Mean Residence Time ◽  
Linear Pharmacokinetic ◽  
Non Linear ◽  
Time Concepts

scholarly journals How many reservoirs? An analysis of flow recessions from a glacier basin

1993 ◽  
Vol 39 (132) ◽  
pp. 409-414 ◽  
Author(s):  
Angela M. Gurnell
Keyword(s):  
Residence Time ◽  
Mean Residence Time ◽  
Hydrological Processes ◽  
Storage Element ◽  
Flow Component ◽  
Recession Curves ◽  
Operational Forecasting ◽  
Non Linear ◽  
Adequate Representation ◽  
Linear Reservoir

Abstract Analysis of hydrograph-recession curves from temperate catchments has frequently been directed towards identifying a linear-storage element with mean residence time Κ which characterizes the delayed-flow component. This paper presents the results of applying such an analysis to recession curves from 11 years of discharge records from a glacier basin. Four reservoirs are identified but their estimated recession coefficients (K values) are found to vary with discharge and with time in the ablation season. This implies that the reservoirs are non-linear. Whilst it may be helpful for the interpretation of glacier-hydrological processes to identify several reservoirs, it appears that a single non-linear reservoir may provide an adequate representation of the glacier for operational forecasting purposes.

scholarly journals How many reservoirs? An analysis of flow recessions from a glacier basin

1993 ◽  
Vol 39 (132) ◽  
pp. 409-414 ◽  
Author(s):  
Angela M. Gurnell
Keyword(s):  
Residence Time ◽  
Mean Residence Time ◽  
Hydrological Processes ◽  
Storage Element ◽  
Flow Component ◽  
Recession Curves ◽  
Operational Forecasting ◽  
Non Linear ◽  
Adequate Representation ◽  
Linear Reservoir

AbstractAnalysis of hydrograph-recession curves from temperate catchments has frequently been directed towards identifying a linear-storage element with mean residence time Κ which characterizes the delayed-flow component. This paper presents the results of applying such an analysis to recession curves from 11 years of discharge records from a glacier basin. Four reservoirs are identified but their estimated recession coefficients (K values) are found to vary with discharge and with time in the ablation season. This implies that the reservoirs are non-linear. Whilst it may be helpful for the interpretation of glacier-hydrological processes to identify several reservoirs, it appears that a single non-linear reservoir may provide an adequate representation of the glacier for operational forecasting purposes.

Precipitation and filtration of zinc, magnesium, copper and aluminium hydroxides

1982 ◽  
Vol 47 (12) ◽  
pp. 3362-3370
Author(s):  
Otakar Söhnel ◽  
Eva Matějčková
Keyword(s):  
Residence Time ◽  
Mean Residence Time ◽  
Filtration Resistance ◽  
Filtration Pressure ◽  
Bed Porosity ◽  
The Mean ◽  
Filtration Properties

Filtration properties of batchwise precipitated suspensions of Zn(OH)2, Mg(OH)2 and Cu(OH)2 and continuously precipitated Al(OH)3 were studied. For batchwise precipitated suspensions was verified the theoretically predicted dependence of specific filtration resistance on initial supersaturation and for the continuously precipitated Al(OH)3 the relation between the specific filtration resistance and the mean residence time of suspension in the reactor. Dependences were also recorded between the bed porosity and concentration of precipitated solutions, specific filtration resistance and used filtration pressure and the effect of aging of the batchwise precipitated suspension of Mg(OH)2on its filtration properties. The used CST method for determination of filtration characteristics of Zn(OH)2 suspension was also studied.

Nitrogen use efficiency: does a trade-off exist between the N productivity and the mean residence time within species?

2008 ◽  
Vol 56 (3) ◽  
pp. 272 ◽  
Author(s):  
Zhi Y. Yuan ◽  
Han Y. H. Chen ◽  
Ling H. Li
Keyword(s):  
Residence Time ◽  
Nitrogen Use Efficiency ◽  
Mean Residence Time ◽  
Negative Relationship ◽  
Controlled Experiments ◽  
Nitrogen Use ◽  
Trade Off ◽  
N Supply ◽  
Use Efficiency ◽  
The Mean

Nitrogen use efficiency (NUE) can be divided into two components, i.e. N productivity (A) and the mean residence time (MRT). Controlled experiments indicate that there is not a trade-off between A and MRT within species, but this theory has not been well tested in field conditions. Here, we studied the A, MRT and NUE of Stipa krylovii Roshev. in a grassland over 4 years of N fertilisation experimentation. The three parameters (A, MRT and NUE) were significantly related to soil N supply and there was a negative relationship between A and MRT within this species (r = –0.775, P < 0.05), i.e. plants with higher A had lower MRT. Our results showed a trade-off between A and MRT within this Stipa species and this observed trade-off was attributed to different responses of A and MRT to soil fertility.

scholarly journals Struvite recovery from solution containing phosphate(V) and sulphate(VI) ions

2015 ◽  
Vol 13 (1) ◽  
Author(s):  
Nina Hutnik ◽  
Anna Kozik ◽  
Krzysztof Piotrowski ◽  
Andrzej Matynia
Keyword(s):  
Product Quality ◽  
Constant Temperature ◽  
Residence Time ◽  
Mean Residence Time ◽  
Crystallization Process ◽  
Magnesium Ions ◽  
Ammonium Ions ◽  
Internal Circulation ◽  
Mean Size ◽  
Type Crystallizer

AbstractThe research results concerning the application of magnesium and ammonium ions for continuous removal of phosphate(V) ions from solution containing 1.0 or 0.20 mass% of PO43– and from 0.10 to 0.50 mass% of SO42– are presented. A continuous struvite MgNH4PO4 × 6H2O reaction crystallization process was carried out both under stoichiometric conditions and using 20% excess of magnesium ions. The research was conducted in a DT MSMPR type crystallizer with internal circulation of suspension driven by a propeller stirrer, in constant temperature 298 K. The pH varied from 9 to 11 and mean residence time of suspension in a crystallizer τ varied from 900 to 3600 s. It was concluded, that sulphate(VI) ions influenced product quality disadvantageously. Depending on process parameter combinations struvite crystals of mean size from ca. 18 to ca. 44 μm and of moderate homogeneity: CV 7–95% were produced. Presence of sulphate(VI) ions favored crystallization of struvite as prismatic crystals, but tubular forms were also identified. The best shaped struvite crystals were produced at relatively low concentration of sulphate(VI) ions, pH 9 and for mean residence time of suspension in a crystallizer elongated up to 3600 s.

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