Optimal Contraception Control for a Nonlinear Vermin Population Model with Size-Structure

2017 ◽  
Vol 79 (2) ◽  
pp. 231-256
Author(s):  
Rong Liu ◽  
Guirong Liu
Keyword(s):  
Population Model ◽  
Size Structure ◽  
Contraception Control

Measure-valued solutions to size-structured population model of prey controlled by optimally foraging predator harvester

2019 ◽  
Vol 29 (09) ◽  
pp. 1657-1689
Author(s):  
Jȩdrzej Jabłoński ◽  
Dariusz Wrzosek
Keyword(s):  
Population Model ◽  
Numerical Solutions ◽  
Size Structure ◽  
Prey Size ◽  
Mortality Rates ◽  
Net Energy ◽  
Structured Population Model ◽  
Size Dependent ◽  
Structured Population ◽  
Net Energy Intake

Radon-measure-valued solutions to a size structured population model of the McKendrick–von Foerster-type are analytically studied under general assumptions on individuals’ growth, birth and mortality rates. The model is used to describe changes in size structure of zooplankton when prey size-dependent mortality rate is a consequence of a planktivorous fish foraging in low prey-density environment (commonly found in predator-controlled populations). The model of foraging is based on the optimization of the rate of net energy intake as a function of predator speed. Mortality is defined as an operator on a metric space of nonnegative Radon measures equipped with the bounded Lipschitz distance. The solutions to the size structured model of zooplankton population are studied analytically and numerically. Numerical solutions (derived using the Escalator Boxcar Train (EBT)-like schema), in particular those starting from Dirac deltas corresponding to distinct cohorts, exhibit regularization in time and convergence to the same stationary state.

Structure and composition of metal particles in Pt-Sn/Al2O3 bimetallic catalysts

1990 ◽  
Vol 48 (4) ◽  
pp. 278-279
Author(s):  
A. Sachdev ◽  
J. Schwank
Keyword(s):  
Bimetallic Catalysts ◽  
Bimetallic Catalyst ◽  
Size Structure ◽  
High Surface ◽  
High Surface Area ◽  
Metal Particles ◽  
Alloy Formation ◽  
Particle Size Range ◽  
Oxide Supports ◽  
Petroleum Fractions

Platinum - tin bimetallic catalysts have been primarily utilized in the chemical industry in the catalytic reforming of petroleum fractions. In this process the naphtha feedstock is converted to hydrocarbons with higher octane numbers and high anti-knock qualities. Most of these catalysts contain small metal particles or crystallites supported on high surface area insulating oxide supports. The determination of the structure and composition of these particles is crucial to the understanding of the catalytic behavior. In a bimetallic catalyst it is important to know how the two metals are distributed within the particle size range and in what way the addition of a second metal affects the size, structure and composition of the metal particles. An added complication in the Pt-Sn system is the possibility of alloy formation between the two elements for all atomic ratios.

Sign in / Sign up

Export Citation Format

Share Document