# Danang Defi Study Group – week #15

**Published by:** [David Ryan](https://paragraph.com/@drcoder/)
**Published on:** 2022-09-08
**URL:** https://paragraph.com/@drcoder/danang-defi-study-group-week-15

## Content

Time: 9:30am on 7th Sept 2022 Location: Draper Startup House My Khe Beach, Danang, Vietnam Present: 7 people Demo: Flash loans using Solidity and Javascript. We talked about:The Aave contract on Ethereum mainnet which has a flashloan method, that borrows potentially all of an asset in Aave, but only for the duration of 1 transaction, and charging a 0.09% feeDeploying another custom contract to call the Aave flashloan and arbitrage prices between Uniswap and Kyber exchangesScanning Uniswap and Kyber data feeds locally using Javascript. Finding arbitrage opportunities. Submitting them to the custom contract as data. The custom contract then executes the arbitrage, using funds from the flashloan. How if the funds are not returned to Aave, the transaction fails.Checksums on Ethereum addresses (such as my address 0x7349d6e55cB3F737249FbAa047C16b826559B127) – how the mixture of lower case and upper case letters can be used to check if an Ethereum address is valid, and prevent sending assets to the wrong address. Claiming POAPs using POAP Delivery: https://poap.delivery Viewing POAPs using the POAP App: https://app.poap.xyz/ Checking mainnet gas prices at: Watch The Burn (this will probably cease service soon) https://watchtheburn.com My own release of “Ethereum Merge Fractal NFT”, to celebrate the Ethereum Merge and raise funds for Ethereum core developers via Protocol Guild. Announcement on Twitter: https://twitter.com/davidryan59/status/1566411577095749632 How to use ABI Ninja to mint automatically (instructional video in thread above) https://abi.ninja/0xCeaAb19BaB4AdBc831b98A4Cf54A6A85A79218a4 View the whole collection on OpenSea, we talked about how to view and analyse the attributes for rarity value: https://opensea.io/collection/mergefractals I was goaded into minting a YEET degen NFT here: https://etherscan.io/token/0x4b13e4107b62cdcb96e0ad84ad4bc2f684440d13?a=2876 And told to list it for sale on OpenSea – it sold! https://opensea.io/assets/ethereum/0x4b13e4107b62cdcb96e0ad84ad4bc2f684440d13/2876 We also played a quick round of Dark Forest via DF DAO Grand Prix, you can check out their Twitter here for announcements of future rounds: https://twitter.com/d_fdao Thanks everyone for meeting! This was week 15, I don’t think I’ll get time to retrospectively put up meeting notes for weeks 1 to 14, but am happy to revisit any important items from those weeks and get the web links into a future article. Hopefully the notes and links in this article are a great reminder of what we discussed! PS - the Ethereum Merge is nearly upon us!

## Publication Information

- [David Ryan](https://paragraph.com/@drcoder/): Publication homepage
- [All Posts](https://paragraph.com/@drcoder/): More posts from this publication
- [RSS Feed](https://api.paragraph.com/blogs/rss/@drcoder): Subscribe to updates
- [Twitter](https://twitter.com/davidryan59): Follow on Twitter