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Update LCA-Results.md
Add link to contribution analysis paper and fix minor errors
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activity_browser/docs/wiki/LCA-Results.md

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@@ -18,6 +18,9 @@ Activity Browser has three contribution analysis approaches available to assess
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`Elementary Flow (EF) Contributions`, `Process contributions` and `First Tier (FT) Contributions`.
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Before we discuss the different approaches, we introduce a small example for the production of _'steel'_:
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These approaches are extensively discussed independent of Activity Browser by
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[van der Meide et al. (2025)](https://doi.org/10.31219/osf.io/sfgj6_v1)
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if you want to learn more.
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![steel production example](./assets/steel_production_example.svg)
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@@ -33,7 +36,8 @@ The amounts we use are:
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<b>Note:</b> These numbers are used for ease of understanding, not for realism.
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</sup>
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To produce 1 kg of steel, we get a climate change impact of 1.6 kg CO2 eq with the _'IPCC 2021'_ impact category.
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To produce 1 kg of steel, we get a climate change impact of 1.6 kg CO<sub>2</sub> eq. with the
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_'IPCC 2021 GWP 100'_ impact category.
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In the way Brightway (and thus Activity Browser) calculate results, a _contribution matrix_ is calculated with
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all impacts _from_ all EFs and all activities.
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For the system and functional unit above, this would be:
@@ -46,15 +50,15 @@ For the system and functional unit above, this would be:
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The _contribution matrix_ show the dis-aggregated results for each individual biosphere flow for each activity.
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#### Elementary Flow (EF) contributions
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If we take sum the _rows_ to one row, we get the EF contributions
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If we take the sum the _rows_ to one column, we get the EF contributions
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(the contribution of all CO<sub>2</sub> and CH<sub>4</sub> impacts together).
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In the case above, the EF contributions are:
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- CO<sub>2</sub>: 1.5404... (96.3%)
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- CH<sub>4</sub>: 0.0596... (3.7%)
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#### Process contributions
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If we take the sum of the _columns_ to one column, we get the process contributions
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If we take the sum of the _columns_ to one row, we get the process contributions
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(the contribution of all coal, electricity and steel production impacts together).
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In the case above, the process contributions are:
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## Sankey
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The `Sankey` tab shows results from [graph traversal](https://docs.brightway.dev/projects/graphtools/en/latest/index.html).
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Graph traversal calculates results step-by-step for _nodes_ (activites) in the _graph_ (supply chain/product system).
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This is explained in detail by
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[van der Meide et al. (2025)](https://doi.org/10.31219/osf.io/sfgj6_v1) (path contributions).
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### Sankey configuration
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In the `Sankey` tab, you can configure, you can set the
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In the `Sankey` tab, you can set the
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Reference flow, Impact category and Scenario (only available in scenario LCA, see [scenarios](#scenarios)) to be shown.
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you can also set a `cutoff` and `calculation depth` setting.
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