HyCAN-DB v1.0 protocol: pre-registered search, sampling, extraction and analysis plan for hydrogen uptake on carbon sorbents

Pre-registered protocol for HyCAN-DB v1.0, an open database and meta-analysis of hydrogen uptake measurements on carbon sorbents. It was registered before any v1.0 search request was sent and before any new paper was sampled or read. The protocol specifies the search of OpenAlex and Semantic Scholar; title and abstract screening by two independent agents; a stratified probability sample of eligible papers, with the draw order seeded from the SHA-256 of the committed sampling frame; blind dual extraction with reconciliation; author audits of screening and extraction; and the analysis plan for five research questions. The primary question asks whether the maximum Gibbs-excess H2 uptake of carbon sorbents at 77 K agrees with the Chahine rule (1 wt% per 500 m2/g of BET area) within an equivalence margin of ±15%. Files, identical to commit 0190009f414488812c84d7f3bee8753cdc54f6a4 of https://github.com/AvinGupta-ship-it/hycan-db: v1_protocol.md (docs/), the protocol; schema.py (src/hycan/) and data_dictionary.md (docs/), the extraction schema, version 2; requirements-v1.lock, the pinned software versions. SHA-256: v1_protocol.md 5e77195d4215f7013847ea314f13165e3c2df87d107568b8ba46426326079498; schema.py 40224df6a1804d80e9a00336279b8a2f9a7159e894fc53de9d1945ba6d448219; data_dictionary.md 91a102fda438eccb5c29c1c15d6d7d537175280fcfbf2e50920b13763dcd7176; requirements-v1.lock 4b4ca40e4e4873a78f558822a9c32fee4e100c7de105f5d7774909435de359a6. After registration the protocol is not edited. Changes are made only as dated amendments appended to its section 15, each stating which data had been seen when it was made. AI use: the protocol, schema and code were drafted with Anthropic Claude models under the author's direction and reviewed by independent Claude agents. The author is responsible for all content. The agent roles in the study are specified in section 13 of the protocol and logged in docs/ai_usage_log.md in the repository.