Text Processing

Extract clean dialogue text from pasted SRT, ASS, or SSA subtitles.

Science & Education

Plot an acid–base titration curve, mark buffer and equivalence landmarks, and explain the Henderson–Hasselbalch steps.

AI Tools

Study public Reddit discussions around a topic with multilingual query expansion, evidence-aware synthesis, themes, sentiment, and a cautious conclusion.

Math & Numbers

Convert angular velocity (angular speed) between radian per second (rad/s, SI base), revolutions per minute (rpm = 2π/60 rad/s), degrees per second (deg/s = π/180 rad/s), and hertz (Hz, used as revolution per second = 2π rad/s). Converts via rad/s to the target unit and lists all four equivalents. Note: 1 Hz in angular-frequency context means one full revolution per second, so 1 Hz = 2π rad/s ≈ 6.283185307 rad/s. Reference: vinyl LP 33⅓ rpm ≈ 3.49 rad/s, car engine idle ~800 rpm ≈ 83.8 rad/s.

Math & Numbers

Convert radioactivity (radionuclide activity) between becquerel (Bq, SI base = 1 decay/s), kilo/mega/gigabecquerel, curie (Ci = 3.7×10^10 Bq, exact 1950 ICRU definition, originally the activity of 1 g of radium-226), milli/microcurie, and disintegrations per minute (dpm = 1/60 Bq, exact). Converts via becquerel to the target unit and lists the equivalent value in all eight units. Reference: banana (K-40) ≈ 15 Bq, smoke detector (Am-241) ≈ 37 kBq = 1 µCi.

Health

Estimate the average steady-state plasma concentration under repeated fixed-interval dosing: Css,avg = (F · Dose) / (CL · τ), where F is bioavailability (1 for IV, <1 for oral), CL is clearance, and τ is the dosing interval. If t½ and Vd are also provided, computes the one-compartment IV-bolus accumulation index Rac = 1/(1-e^(-kτ)), peak Cmax,ss, trough Cmin,ss, and time to ~94%/~97% of steady state (4/5 half-lives). Valid only for linear pharmacokinetics with fixed dose and interval — NOT for Michaelis-Menten drugs or non-linear kinetics. Not medical advice.

Astronomy

Plan observations with local sidereal time, optional nutation, precessed coordinates, and altitude/azimuth slots.

Math & Numbers

Convert illuminance between lux (lx = lm/m², SI base), kilolux (1 = 1000 lx), footcandle (1 = 10.7639104 lx), phot (1 = 10000 lx), and nox (1 = 0.001 lx). Converts via lux to the target unit and lists the equivalent value in all five units for reference. Reference values: full moon ≈ 0.25, office lighting ≈ 300–500, overcast day ≈ 1000, direct sunlight ≈ 100000 lux.

Math & Numbers

Convert radiation absorbed dose between Gy (gray = J/kg, SI base), kGy (1 = 1000 Gy), cGy (1 = 0.01 Gy), mGy (1 = 0.001 Gy), and rad (1 = 0.01 Gy). Converts via Gy to the target unit and lists the equivalent value in all five units. ⚠️ Absorbed dose is NOT equivalent dose: converting Gy → Sv requires multiplying by the radiation weighting factor w_R (X/γ/β = 1, neutrons 5–20, alpha 20) — use the dose-equivalent converter for that side. Reference values: chest X-ray ≈ 1e-4, CT scan ≈ 1e-2, radiotherapy fraction ≈ 2, whole-body LD50/60 ≈ 4–6 Gy.

Math & Numbers

Convert radiation equivalent dose between Sv (sievert, SI base), mSv (1 = 0.001 Sv), µSv (1 = 1e-6 Sv), rem (1 = 0.01 Sv), and mrem (1 = 1e-5 Sv). Converts via Sv to the target unit and lists the equivalent value in all five units. ⚠️ Equivalent dose is NOT absorbed dose: equivalent dose = absorbed dose (Gy) × radiation weighting factor w_R (X/γ/β = 1, neutrons 5–20, alpha 20). Converting Sv → Gy requires dividing by w_R — use the absorbed-dose converter for that side. Reference values: natural background ≈ 3 mSv/yr, chest CT ≈ 7 mSv, annual occupational limit ≈ 50 mSv/yr, ARS threshold ≈ 1 Sv.

Math & Numbers

Convert sound power between linear units (W, mW, µW, pW) and the decibel sound power level dB Lw (Lw = 10·log₁₀(W / 1 pW), reference P₀ = 1 pW = 1e-12 W, per ISO 3744 / IEC 60027-3). Supports bidirectional linear↔logarithmic conversion and reports the equivalent value in all five units. Reference values: whisper ≈ 1e-9 W (Lw ≈ 30), speech ≈ 1e-5 W (Lw ≈ 70), jet engine at 1 m ≈ 1e4 W (Lw ≈ 160).

Math & Numbers

Convert sound pressure between linear units (Pa, µPa, µbar, mbar) and the decibel sound pressure level dB SPL (Lp = 20·log₁₀(p / 20 µPa), reference p₀ = 20 µPa = 2e-5 Pa RMS, per ISO 1683). Supports bidirectional linear↔logarithmic conversion. Calibration anchor: 1 Pa → 20·log₁₀(1/2e-5) ≈ 94 dB SPL. Reference values: threshold of hearing 20 µPa (0 dB), speech ≈ 0.02 Pa (60 dB), rock concert ≈ 20 Pa (120 dB), pain threshold ≈ 200 Pa (140 dB).