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Combining electromobility and renewable energies since 2014.

http://www.amsterdamvehicle2grid.nl/

Amsterdam V2G simulation 2.0
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Food web based off of organisms within Yellowstone. For Bio 40

Food Web Insight
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From Jay Forrester 1971 Book World Dynamics, the earlier, simpler version of Scott Fortmann-Roe's World 3 Limits to Growth Model. adapted from Mark Heffernan's ithink version 

World2 Model of World Dynamics
59 2 months ago
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This is a simple Model of the Food Chain
Clone of Food Chain
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A storytelling of the nitrogen cycle.
Nitrogen Cycle
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Simple mass balance model for lakes, based on the Vollenweider equation:

dMw/dt = Min - sMw - Mout

The model was first used in the 1960s to determine the phosphorus concentration in lakes and reservoirs for eutrophication assessment.

This version adds diagenesis, using an extra state variable (phosphorus in the sediment) and incorporates desorption processes that release phosphorus trapped in the sediment back to the water column.

The temporal dynamics of the model simulate the typical development of pollution in time.

1. Low loading, low P concentration in lake
2. High loading, increasing P concentration in lake
3. Desorption rate is low, P in sediment increases
4. Measures implemented for source control, loading reduces
5. P in lake gradually decreases, but below a certain point, desorption increases, and lake P concentration does not improve
6. Recovery only occurs when the secondary load in the sediment is strongly reduced.
Vollenweider model with diagenesis
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Westley, F. R., O. Tjornbo, L. Schultz, P. Olsson, C. Folke, B. Crona and Ö. Bodin. 2013. A theory of transformative agency in linked social-ecological systems. Ecology and Society 18(3): 27. link

Transformative Agency in Social-Ecological System
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Work Cited


E., Kaplan. "Biomes of the World: Tundra." Alpine Biome. Hong Kong: Marshall Cavendish Corporation., n.d. Web. 23 May 2017.     http://www.blueplanetbiomes.org/tundra.htm
Artic Tundra Food Chain
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This model is a classic simulation of the production cycle in the ocean, including the effects of the thermocline in switching off advection of dissolved nutrients and detritus to the surface layer.

It illustrates a number of interesting features including the coupling of three state variables in a closed cycle, the use of time to control the duration of advection, and the modulus function for cycling annual temperature data over multiple years.

The model state variables are expressed in nitrogen units (mg N m-3), and the calibration is based on:

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.

This model was first implemented in PowerSim some years ago by one of my M.Sc. students, who then went on to become a Buddhist monk. Although this is a very Zen model, as far as I'm aware, the two facts are unrelated.
NPD model (Nutrients, Phytoplankton, Detritus)
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Carbon Cycle v0.1
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Clone of Pesticide Use in Central America for Lab work


This model is an attempt to simulate what is commonly referred to as the “pesticide treadmill” in agriculture and how it played out in the cotton industry in Central America after the Second World War until around the 1990s.

The cotton industry expanded dramatically in Central America after WW2, increasing from 20,000 hectares to 463,000 in the late 1970s. This expansion was accompanied by a huge increase in industrial pesticide application which would eventually become the downfall of the industry.

The primary pest for cotton production, bol weevil, became increasingly resistant to chemical pesticides as they were applied each year. The application of pesticides also caused new pests to appear, such as leafworms, cotton aphids and whitefly, which in turn further fuelled increased application of pesticides. 

The treadmill resulted in massive increases in pesticide applications: in the early years they were only applied a few times per season, but this application rose to up to 40 applications per season by the 1970s; accounting for over 50% of the costs of production in some regions. 

The skyrocketing costs associated with increasing pesticide use were one of the key factors that led to the dramatic decline of the cotton industry in Central America: decreasing from its peak in the 1970s to less than 100,000 hectares in the 1990s. “In its wake, economic ruin and environmental devastation were left” as once thriving towns became ghost towns, and once fertile soils were wasted, eroded and abandoned (Lappe, 1998). 

Sources: Douglas L. Murray (1994), Cultivating Crisis: The Human Cost of Pesticides in Latin America, pp35-41; Francis Moore Lappe et al (1998), World Hunger: 12 Myths, 2nd Edition, pp54-55.

Clone of REM 221 - Causal Loop diagramming
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This is a simulation that represents the populations of lions in the world over the last 200 years.
Lion Population Over The Last 200 Years
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Daisyworld is a classic model of planetary feedbacks, due to Andrew Watson and James Lovelock (1983). See http://en.wikipedia.org/wiki/Daisyworld.
Daisyworld
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A simulation illustrating simple predator prey dynamics. You have two populations.

Predator Prey
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As initially proposed by Pr. William M White of Cornell University:

http://www.geo.cornell.edu/eas/education/course/descr/EAS302/302_06Lab11.pdf
http://www.eas.cornell.edu/
Global Carbon Cycle
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Simple Model of the Food Chain
Clone of Food Chain
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Simple energy balance model of a planet with albedo, ocean, and atmosphere.

This simulation models the stock and flow of energy between a star, a planet’s surface (primarily its oceans, which are the largest reservoir of heat), and space.The assumptions governing this model are:

1. The planet absorbs a fraction of the shortwave radiation arriving from its star, with that fraction given by (1-A), where A is albedo. 

2. The planet radiates longwave infrared radiation into space, with the amount of radiation into space given by σΤe4, where σ is the Stefan-Boltzmann constant and Te is the temperature of the effective radiating level.

3. The atmospheric lapse rate is 6 K/km.

4. If there is an imbalance between shortwave radiation absorbed and longwave radiation emitted, the imbalance affects the temperature of the planet. However, it does not do so instantaneously – the imbalance must heat or cool the mixed layer of the ocean.

5. At the start of the simulation, the planet is extremely close to equilibrium given its default parameters. If any of these parameters are changed, the planet will be out of equilibrium, and will have to adjust.

Simple Energy Balance Model
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For school
The Grate Barrier Reef Food Chain
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Clone of IM-1954 to tidy up layout. The World3 model is a detailed simulation of human population growth from 1900 into the future. It includes many environmental and demographic factors.

 

Use the sliders to experiment with the initial amount of non-renewable resources to see how these affect the simulation. Does increasing the amount of non-renewable resources (which could occur through the development of better exploration technologies) improve our future? Also, experiment with the start date of a low birth-rate, environmentally focused policy.

Clone of The World3 Model: A Detailed World Forecaster with Folders
6 2 months ago
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A model of an infectious disease and control

Disease Dynamics (Agent Based Modeling) Guy Lakeman
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A tutorial on the basics of insightmaker
Predatory Prey Model Tutorial
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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
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This model shows how a persistent pollutant such as mercury or DDT can be bioamplified along a trophic chain to levels that result in reduction of top predator populations.
Bioamplification of mercury in a marine system
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General global ocean box model, including isotopes.
GEOSC416 isotope box model w/o mass transience