Astronomy
Solve Galilean satellite positions with Meeus/Lieske E5 series, chart the Laplace-resonance libration, scan mutual events and eclipses, model a Europa Clipper-style flyby with patched-conic Δv, and solve Jupiter Cassini states from J2 oblateness precession.
jovian-galilean-moons-europa-flyby-cassini-state-and-resonance-solverDesign
Generate art QR codes with brand colors, gradients, rounded or dot modules and a centered logo, plus the ISO mask-penalty breakdown, per-module metadata export and a Reed–Solomon erasure-budget verdict.
qr-code-art-styled-module-and-logo-embed-generatorDevelopment
Simulate the Authorization Code flow with PKCE end to end: verifier/challenge generation, authorization URL, token exchange, ID Token validation checklist and an interception-attack demo.
oauth-oidc-authorization-code-pkce-flow-visualizerNetwork
Parse RFC 8288 Link headers with the spec appendix-B algorithm, resolve relative URI-references against a base URL, classify rel types against the IANA registry, validate preload/prefetch hints, and simulate how a rel="next" pagination crawler walks your responses — including cycle detection.
http-link-header-rfc8288-parser-and-pagination-crawler-previewSports
Plan a HYROX race end to end: per-lap 1 km run splits under an even, negative-split or fade strategy, auto-distributed station targets for your finish time, the 8 Roxzone transition budget, and your division’s official sled push/pull weights with the plate stack to load.
hyrox-race-station-split-and-sled-loading-plannerScience & Education
t½ = a₀/(2k), ln 2/k or 1/(k·a₀) for zero-, first- and second-order reactions, with timelines and depletion time.
half-life-reaction-orderDevelopment
Test java.util.regex patterns online: (?<name>…) named groups, possessive quantifiers and atomic groups, Pattern flags, ASCII vs UNICODE_CHARACTER_CLASS \d semantics, and ready-to-paste Java code.
java-regex-testerDevelopment
Test Python re patterns online: (?P<name>…) named groups, (?P=name) backreferences, VERBOSE patterns, findall behavior, and \g<name> replace templates — plus ready-to-paste Python code.
python-regex-testerScience & Education
E⁰cell = E⁰cathode − E⁰anode with ΔG⁰, the spontaneity verdict, and log₁₀K at 25 °C.
galvanic-cell-emfScience & Education
Hall voltage V_H = I·B/(n·q·t) with signed carrier charge, density in m⁻³ or cm⁻³, the Hall coefficient R_H, and sensitivity in V/T.
hall-effect-calculatorScience & Education
Energy-flow density S = E × H = (1/μ₀) E × B with unit selectors, H = B/μ₀, both energy densities, and the plane-wave check where S = c·u.
poynting-vectorScience & Education
dτ = dt·√(1 − 2GM/(rc²)) for Earth, Sun, or custom mass: Schwarzschild radius, dilation factor, and daily/yearly clock lag outside the horizon.
gravitational-time-dilation