Effect of reaction-rate on leaching of phosphate through sandy soils of Western-Australia

Soil Research ◽  
1995 ◽  
Vol 33 (1) ◽  
pp. 211 ◽  
Author(s):  
RG Gerritse
Keyword(s):  
Computer Simulation ◽  
Reaction Rate ◽  
Empirical Equation ◽  
Sandy Soils ◽  
Breakthrough Curves ◽  
Computer Simulation Model ◽  
Input Concentration ◽  
Flow Rates ◽  
Field Situation ◽  
Leaching Experiments

The effect of reaction rate on the mobility of phosphate in soils was measured from breakthrough curves in the leachate from small columns of soil, following step increases in the input concentration of phosphate. Average mobilities of phosphate in columns of soil, following a step increase in the input concentration, decrease with decreasing rate of flow and with increasing distance travelled and appear to be linearly correlated on a log-log scale with both flow rate and distance travelled. An empirical equation, describing these relationships, fits data from leaching experiments at flow rates between 30 and 600 cm/day in columns of soil ~10-30 cm in length. Two coefficients are required and are obtained by curve fitting breakthrough curves, calculated with a numerical computer simulation model, to experimental breakthrough curves. The fitted equation enables extrapolation to flow rates and distances travelled that are more relevant to a field situation.

Theory of CO2 Exchange in Trout Gills

1974 ◽  
Vol 60 (1) ◽  
pp. 183-194
Author(s):  
JAMES N. CAMERON ◽  
JOHN A. POLHEMUS
Keyword(s):  
Experimental Data ◽  
Computer Simulation ◽  
Water Flow ◽  
Reaction Rate ◽  
Co2 Exchange ◽  
Co2 Efflux ◽  
Flow Rates ◽  
Reaction Rate Constants ◽  
Co2 Output ◽  
Extreme Sensitivity

1. A computer simulation of countercurrent CO2 exchange in fish gills was constructed to examine effects of variations in blood and water flow rates. 2. CO2 output was sensitive to both blood and water flow rates, contrary to experimental data. 3. Various explanations of the contradiction are discussed, including patterns of gill perfusion and possible shunting of blood. 4. A simplified version of the model was also used to demonstrate extreme sensitivity of CO2 efflux to variations of the residence time of blood in the gills. 5. Data from the literature on reaction rate constants for the CO2/carbonate/ bicarbonate system are summarized, and the importance of some of these reactions is examined.

Biochar caged zirconium ferrite nanocomposites for the adsorptive removal of Reactive Blue 19 dye in a batch and column reactors and conditions optimizaton

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Shazia Perveen ◽  
Raziya Nadeem ◽  
Shaukat Ali ◽  
Yasir Jamil
Keyword(s):  
Experimental Data ◽  
Low Dose ◽  
Fixed Bed ◽  
Breakthrough Curves ◽  
Adsorption Efficiency ◽  
Fixed Bed Column ◽  
Flow Rates ◽  
Adsorptive Removal ◽  
Reactive Blue 19 ◽  
Pseudo Second Order

Abstract Biochar caged zirconium ferrite (BC-ZrFe2O5) nanocomposites were fabricated and their adsorption capacity for Reactive Blue 19 (RB19) dye was evaluated in a fixed-bed column and batch sorption mode. The adsorption of dye onto BC-ZrFe2O5 NCs followed pseudo-second-order kinetics (R 2 = 0.998) and among isotherms, the experimental data was best fitted to Sips model as compared to Freundlich and Langmuir isotherms models. The influence of flow-rate (3–5 mL min−1), inlet RB19 dye concentration (20–100 mg L−1) and quantity of BC-ZrFe2O5 NCs (0.5–1.5 g) on fixed-bed sorption was elucidated by Box-Behnken experimental design. The saturation times (C t /C o  = 0.95) and breakthrough (C t /C o  = 0.05) were higher at lower flow-rates and higher dose of BC-ZrFe2O5 NCs. The saturation times decreased, but breakthrough was increased with the initial RB19 dye concentration. The treated volume was higher at low sorbent dose and influent concentration. Fractional bed utilization (FBU) increased with RB19 dye concentration and flow rates at low dose of BC-ZrFe2O5 NCs. Yan model was fitted best to breakthrough curves data as compared to Bohart-Adams and Thomas models. Results revealed that BC-ZrFe2O5 nanocomposite has promising adsorption efficiency and could be used for the adsorption of dyes from textile effluents.

Quality safety of agricultural products in supply chain-computer simulation based on multi-agent system

2021 ◽  
pp. 1-8
Author(s):  
Wei Zhou ◽  
Maha Saad Metawea
Keyword(s):  
Computer Simulation ◽  
Supply Chain ◽  
Agricultural Products ◽  
Computer Simulation Model ◽  
Quality And Safety ◽  
Multi Agent System ◽  
Agent System ◽  
Supply Chain System ◽  
Multi Agent ◽  
Countermeasures And Suggestions

As is known that, one of the challenges in ensuring the quality and safety of agricultural products in China is how to organize plenty of scattered small farmers and integrate them into the modern agricultural products supply chain system. In this paper, in order to promote the tight integration of agricultural products supply chain, based on multi-agent system, a computer simulation model of agricultural products supply chain is proposed. Through a series of simulation experiments, the evolution of the organizational structure of the agricultural products supply chain, its impact on the quality and safety of agricultural products under different government regulations are explored and discussed in detail. It follows from these simulation results that the more long-term-contract farmers and sellers, the more conducive to the improvement of the quality and safety of agricultural products, and the corresponding countermeasures and suggestions are also provided.

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