{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2015:ONPL34OZLHJUHZG2JDVWCDO2RR","short_pith_number":"pith:ONPL34OZ","canonical_record":{"source":{"id":"1504.04805","kind":"arxiv","version":2},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cond-mat.soft","submitted_at":"2015-04-19T07:20:47Z","cross_cats_sorted":[],"title_canon_sha256":"abca08078f16fb62e866358859cc6ebc39972595afc09faa06cea54c3cbcc77c","abstract_canon_sha256":"8e123724a10d672a12f825c4eac23d67f2de19c8c0d3633e9678b12751d5180d"},"schema_version":"1.0"},"canonical_sha256":"735ebdf1d959d343e4da48eb610dda8c7832758e45498b7132f2ceb27d90ccf8","source":{"kind":"arxiv","id":"1504.04805","version":2},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1504.04805","created_at":"2026-05-18T01:22:48Z"},{"alias_kind":"arxiv_version","alias_value":"1504.04805v2","created_at":"2026-05-18T01:22:48Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1504.04805","created_at":"2026-05-18T01:22:48Z"},{"alias_kind":"pith_short_12","alias_value":"ONPL34OZLHJU","created_at":"2026-05-18T12:29:34Z"},{"alias_kind":"pith_short_16","alias_value":"ONPL34OZLHJUHZG2","created_at":"2026-05-18T12:29:34Z"},{"alias_kind":"pith_short_8","alias_value":"ONPL34OZ","created_at":"2026-05-18T12:29:34Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2015:ONPL34OZLHJUHZG2JDVWCDO2RR","target":"record","payload":{"canonical_record":{"source":{"id":"1504.04805","kind":"arxiv","version":2},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cond-mat.soft","submitted_at":"2015-04-19T07:20:47Z","cross_cats_sorted":[],"title_canon_sha256":"abca08078f16fb62e866358859cc6ebc39972595afc09faa06cea54c3cbcc77c","abstract_canon_sha256":"8e123724a10d672a12f825c4eac23d67f2de19c8c0d3633e9678b12751d5180d"},"schema_version":"1.0"},"canonical_sha256":"735ebdf1d959d343e4da48eb610dda8c7832758e45498b7132f2ceb27d90ccf8","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T01:22:48.511526Z","signature_b64":"24bzG/aOBDpBsI+ETrN6+ziLJp4sFVpUesBVAb/PyyiorQf/4/Ib6ZL/3Rw/RxMp70w/mAiA/sr4NrUn8VoZCw==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"735ebdf1d959d343e4da48eb610dda8c7832758e45498b7132f2ceb27d90ccf8","last_reissued_at":"2026-05-18T01:22:48.510969Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T01:22:48.510969Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1504.04805","source_version":2,"attestation_state":"computed"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-18T01:22:48Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"XjtH1KMxWti3oD31zkxp6FutTvVV8L0g6CIAmpQb3x0NbKjeTOeeLK8mkBoi3tzgi19sroOZ4CBUDVIgCxOaDw==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-27T23:59:22.916552Z"},"content_sha256":"fc2786cdac8a58ab83583019c7ec0b22493d7fedad2fabdb7395443b4fe4176f","schema_version":"1.0","event_id":"sha256:fc2786cdac8a58ab83583019c7ec0b22493d7fedad2fabdb7395443b4fe4176f"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2015:ONPL34OZLHJUHZG2JDVWCDO2RR","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Drag Law of Two Dimensional Granular Fluids","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"cond-mat.soft","authors_text":"Hisao Hayakawa, Satoshi Takada","submitted_at":"2015-04-19T07:20:47Z","abstract_excerpt":"The drag force law acting on a moving circular disk in a two-dimensional granular medium is analyzed based on the discrete element method (DEM). It is remarkable that the drag force on the moving disk in moderate dense and pure two-dimensional granular medium can be well reproduced by a perfect fluid with separation from the surface of the tracer. A yield force, being independent of the moving speed of the disk, appears if a dry friction between the granular disks and the bottom plate exists. The perfect fluidity is violated in this case. The yield force and the drag force diverge at the jammi"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1504.04805","kind":"arxiv","version":2},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"},"verdict_id":null},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-18T01:22:48Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"hRZ1RVlcu5Sar4KG18GkqA0bpLtdG037RDyhXbXYFp0gPffg3RZjeSeOxbxdBoy9cUOU3oXCy91DrGIG6m+nDw==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-27T23:59:22.917221Z"},"content_sha256":"4f35d1ca5d92a1d3b053f9dce3b57401e5980f418ecb1a0c79f7b2487d07cddf","schema_version":"1.0","event_id":"sha256:4f35d1ca5d92a1d3b053f9dce3b57401e5980f418ecb1a0c79f7b2487d07cddf"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/ONPL34OZLHJUHZG2JDVWCDO2RR/bundle.json","state_url":"https://pith.science/pith/ONPL34OZLHJUHZG2JDVWCDO2RR/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/ONPL34OZLHJUHZG2JDVWCDO2RR/bundle.json","status":"primary"}],"public_keys":[{"key_id":"pith-v1-2026-05","algorithm":"ed25519","format":"raw","public_key_b64":"stVStoiQhXFxp4s2pdzPNoqVNBMojDU/fJ2db5S3CbM=","public_key_hex":"b2d552b68890857171a78b36a5dccf368a953413288c353f7c9d9d6f94b709b3","fingerprint_sha256_b32_first128bits":"RVFV5Z2OI2J3ZUO7ERDEBCYNKS","fingerprint_sha256_hex":"8d4b5ee74e4693bcd1df2446408b0d54","rotates_at":null,"url":"https://pith.science/pith-signing-key.json","notes":"Pith uses this Ed25519 key to sign canonical record SHA-256 digests. Verify with: ed25519_verify(public_key, message=canonical_sha256_bytes, signature=base64decode(signature_b64))."}],"merge_version":"pith-open-graph-merge-v1","built_at":"2026-05-27T23:59:22Z","links":{"resolver":"https://pith.science/pith/ONPL34OZLHJUHZG2JDVWCDO2RR","bundle":"https://pith.science/pith/ONPL34OZLHJUHZG2JDVWCDO2RR/bundle.json","state":"https://pith.science/pith/ONPL34OZLHJUHZG2JDVWCDO2RR/state.json","well_known_bundle":"https://pith.science/.well-known/pith/ONPL34OZLHJUHZG2JDVWCDO2RR/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2015:ONPL34OZLHJUHZG2JDVWCDO2RR","merge_version":"pith-open-graph-merge-v1","event_count":2,"valid_event_count":2,"invalid_event_count":0,"equivocation_count":0,"current":{"canonical_record":{"metadata":{"abstract_canon_sha256":"8e123724a10d672a12f825c4eac23d67f2de19c8c0d3633e9678b12751d5180d","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cond-mat.soft","submitted_at":"2015-04-19T07:20:47Z","title_canon_sha256":"abca08078f16fb62e866358859cc6ebc39972595afc09faa06cea54c3cbcc77c"},"schema_version":"1.0","source":{"id":"1504.04805","kind":"arxiv","version":2}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1504.04805","created_at":"2026-05-18T01:22:48Z"},{"alias_kind":"arxiv_version","alias_value":"1504.04805v2","created_at":"2026-05-18T01:22:48Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1504.04805","created_at":"2026-05-18T01:22:48Z"},{"alias_kind":"pith_short_12","alias_value":"ONPL34OZLHJU","created_at":"2026-05-18T12:29:34Z"},{"alias_kind":"pith_short_16","alias_value":"ONPL34OZLHJUHZG2","created_at":"2026-05-18T12:29:34Z"},{"alias_kind":"pith_short_8","alias_value":"ONPL34OZ","created_at":"2026-05-18T12:29:34Z"}],"graph_snapshots":[{"event_id":"sha256:4f35d1ca5d92a1d3b053f9dce3b57401e5980f418ecb1a0c79f7b2487d07cddf","target":"graph","created_at":"2026-05-18T01:22:48Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"graph_snapshot":{"author_claims":{"count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","strong_count":0},"builder_version":"pith-number-builder-2026-05-17-v1","claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"paper":{"abstract_excerpt":"The drag force law acting on a moving circular disk in a two-dimensional granular medium is analyzed based on the discrete element method (DEM). It is remarkable that the drag force on the moving disk in moderate dense and pure two-dimensional granular medium can be well reproduced by a perfect fluid with separation from the surface of the tracer. A yield force, being independent of the moving speed of the disk, appears if a dry friction between the granular disks and the bottom plate exists. The perfect fluidity is violated in this case. The yield force and the drag force diverge at the jammi","authors_text":"Hisao Hayakawa, Satoshi Takada","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cond-mat.soft","submitted_at":"2015-04-19T07:20:47Z","title":"Drag Law of Two Dimensional Granular Fluids"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1504.04805","kind":"arxiv","version":2},"verdict":{"created_at":null,"id":null,"model_set":{},"one_line_summary":"","pipeline_version":null,"pith_extraction_headline":"","strongest_claim":"","weakest_assumption":""}},"verdict_id":null}}],"author_attestations":[],"timestamp_anchors":[],"storage_attestations":[],"citation_signatures":[],"replication_records":[],"corrections":[],"mirror_hints":[],"record_created":{"event_id":"sha256:fc2786cdac8a58ab83583019c7ec0b22493d7fedad2fabdb7395443b4fe4176f","target":"record","created_at":"2026-05-18T01:22:48Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"attestation_state":"computed","canonical_record":{"metadata":{"abstract_canon_sha256":"8e123724a10d672a12f825c4eac23d67f2de19c8c0d3633e9678b12751d5180d","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cond-mat.soft","submitted_at":"2015-04-19T07:20:47Z","title_canon_sha256":"abca08078f16fb62e866358859cc6ebc39972595afc09faa06cea54c3cbcc77c"},"schema_version":"1.0","source":{"id":"1504.04805","kind":"arxiv","version":2}},"canonical_sha256":"735ebdf1d959d343e4da48eb610dda8c7832758e45498b7132f2ceb27d90ccf8","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"735ebdf1d959d343e4da48eb610dda8c7832758e45498b7132f2ceb27d90ccf8","first_computed_at":"2026-05-18T01:22:48.510969Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T01:22:48.510969Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"24bzG/aOBDpBsI+ETrN6+ziLJp4sFVpUesBVAb/PyyiorQf/4/Ib6ZL/3Rw/RxMp70w/mAiA/sr4NrUn8VoZCw==","signature_status":"signed_v1","signed_at":"2026-05-18T01:22:48.511526Z","signed_message":"canonical_sha256_bytes"},"source_id":"1504.04805","source_kind":"arxiv","source_version":2}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:fc2786cdac8a58ab83583019c7ec0b22493d7fedad2fabdb7395443b4fe4176f","sha256:4f35d1ca5d92a1d3b053f9dce3b57401e5980f418ecb1a0c79f7b2487d07cddf"],"state_sha256":"360d406be95936df6f41d095283ce9e24c7e8430b5692871e676c722a1cbad9e"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"CjXXk6BnE0vStva2SgSksF6ViqODOAlvAOuR+bhG0qGgTDAn8NHYbWjyREzZd3qCdHXKNqpIbyUWFUoV+NR2CQ==","signed_message":"bundle_sha256_bytes","signed_at":"2026-05-27T23:59:22.920173Z","bundle_sha256":"6001a935e7032240d325335dc0ba7cfe828069b4717e93835125c8d2701d5778"}}