This stock and flow diagram is a working draft of a conceptual model of a dune-lake system in the Northland region of New Zealand.
Clone of Stock and flow diagram of phosphorus in a shallow lake
A system dynamics model of a predator-prey lifecycle relationship
Clone of Predator-Prey relationship
Simple model to illustrate an annual cycle for phytoplankton biomass in temperate waters.
Potential primary production uses Steele's equation and a Michaelis-Menten (or Monod) function for nutrient limitation. Respiratory losses are only a function of biomass.
Clone of Phytoplankton model URI
This model describes the N isotope dynamics in a marine system where the shallowness of the chemocline prevents significant nitrification near the base of the photic zone.
N isotope dynamics in a suboxic Paleozoic water column
Fooodwaste happens everywhere and in every part
of the food cycle even if nobody wants it to happen.
We created a local solution to
reduce the waste. This solution is situated in Belgium (Kotrijk) where an
exchange system (for services) already exists and it is called letsleie http://www.letsleie.be.
We did choose letstlei because their
exchange system doesn’t work with money but with a fictive money system
"vlasbloemen". In their system we want to integrate the exchange of
food leftovers. After some years the system could become world wide.
Our solution begins with an event in a
neighbourhood or apartments. This event brings the neighbours together who
don't know each anymore. It explains the existing system and the problems of the
food waste. Every person had to take a leftover and chefs will create a
delicious meal of it. The members will receive a food box who is biodegradable
and contains a QR code that will simplify the food/ service exchange.
People will talk to each other after the event
and more and more people will join without needing new publicity.
Foodwaste Reducing by exchanging
A simple phosphorus model for a generic lake.
Phosphorus in a Lake
The time-variable solution to a step-function change in inflow concentration for an ideal, completely mixed lake.
Clone of Clone of Clone of ENVE 431 - HW5 - PROBLEM 7
Koala Population Dynamic Systems
The following insight shows the level of crime in the town of Bourke in comparison to the levels of Police and Community Engagement
Clone of Crime vs. Engagement
Simple model to illustrate oyster growth based on primary production of Phytoplankton as a state variable, forced by light and nutrients, running for a yearly period.
Phytoplankton growth based on on Steele's and Michaelis-Menten equations), where:
Primary Production=(([Pmax]*[I]/[Iopt]*exp(1-[I]/[Iopt])*[S])/([Ks]+[S]))
Pmax: Maximum production (d-1)
I: Light energy at depth of interest (uE m-2 s-1)
Iopt: Light energy at which Pmax occurs (uE m-2 s-1)
S: Nutrient concentration (umol N L-1)
Ks: Half saturation constant for nutrient (umol N L-1).
Further developments:
- Nutrients as state variable in cycle with detritus from phytoplankton and oyster biomass.
- Light limited by the concentration of phytoplankton.
- Temperature effect on phytoplankton and Oyster growth.
Clone of Oyster Growth based on Phytoplankton Biomass
How the 4-H club became a marketing thingy for DuPont
Clone of 4-H impact on African Farming
This story presents a conceptual model of nitrogen cycling in a dune-lake system in the Northland region of New Zealand. It is based on the concept of a stock and flow diagram. Each orange ellipse represents an input, while each blue box represents a stock. Each arrow represents a flow. A flow involves a loss from the stock at which it starts and an addition to the stock at which it ends.
Clone of Story of nitrogen dynamics in a shallow lake
Ce modèle est une simulation classique du cycle de productivité dans l'océan, incluant les effets de la thermocline pour désactiver l'advection d'éléments nutritifs dissous et de détritus à la couche superficielle.
Ce modèle illustre un certain nombre de caractéristiques intéressantes notamment le lien de trois variables d'état dans un cycle fermé, l'utilisation du temps pour contrôler la durée de l'advection et la fonction modulus pour les données de température qui cyclent annuellement sur plusieurs années.
Les variables d'état du modèle sont exprimées en unités d'azote (mg N m-3), et l'étalonnage est basé sur:
Baliño, B.M. 1996. Eutrophication of the North Sea, 1980-1990: An evaluation of anthropogenic nutrient inputs using a 2D phytoplankton production model. Dr. scient. thesis, University of Bergen.
Fransz, H.G. & Verhagen, J.H.G. 1985. Modelling Research on the Production Cycle of Phytoplankton in the Southern Bight of the Northn Sea in Relation to Riverborne Nutrient Loads. Netherlands Journal of Sea Research 19 (3/4): 241-250.
Traduction du modèle de Joao G Ferreira (https://insightmaker.com/insight/6838/NPD-model-Nutrients-Phytoplankton-Detritus)
Le modèle NPD (nutriments, phytoplancton, détritus) basé sur la productivité primaire de la Mer du Nord - CHANGEMENT TEMPERATURE 1 DEGRE
jute bag project: prototype
European Masters in System Dynamics 2016
New University of Lisbon, Portugal
Simple model to represent oyster individual growth by simulating feeding and metabolism.
EMSD 2016
In Chile,
60% of its population are exposed to levels of Particulate Matter (PM) above international standards. Air Pollution is causing
4,000 premature deaths per year, including health costs over US$8 billion.
The System Dynamics Causal Loop Diagram developed herein shows an initial study of the dynamics among the variables that influences the accumulation of PM in the air, in particular the case of Temuco, in the South of Chile. In Temuco, 97% of the PM inventories comes from the combustion of low quality firewood, which in turns is being burned due to its low price and cultural habits/tradition.
Clone of Air Pollution Dynamics - Firewood Combustion
•Dry
Period Case
–
25 years of historical dry period on record (1947-1973)-including drought of
record (1947-1956)
–Represents
the dry period case
–Future
dry cycle includes dry cycle of AMO and overlay of IPCC climate change
predictions
Clone of Clone of EA dry conditions 1947-1973
This model describes nitrogen cycling in a dune-lake system in the Northland region of New Zealand. It is based on stock and flow diagrams where each orange oval represents an input, while each blue box represents a stock. Each arrow represents a flow. Flows reduce the stock at which they start and add to the stock at which they end.
Clone of Story of nitrogen dynamics in a shallow lake
Modeling forest succession in a northeast deciduous forest.
Lab1 Forestry Succession Model
A simulation illustrating simple predator prey dynamics. You have two populations.
L&I4: Predator Prooi
This diagram provides a stylised description of important feedbacks within a shallow-lake system.
Feedbacks in a shallow lake
