Health

Closed-population size from n₁ marked, n₂ caught, m₂ recaptured: Lincoln–Petersen and Chapman estimates with SE and 95% CI.

Education

MOI from titer/volume/cells or the virus volume for a target MOI, with Poisson % infected. Educational use only.

Education

Mass-to-molar DNA conversion: nM = (µg/mL × 10⁶)/(Da-per-bp × bp) with 650 Da/bp dsDNA and 330 Da/nt ssDNA, plus µM, pmol/µL, total pmol, and molecules/µL via Avogadro. Warns about the µM-vs-nM 1000× slip. NEB NEBioCalculator / Promega BioMath derived. Educational use only.

Education

DNA/RNA working-solution prep: C1V1 = C2V2 mode solves the stock volume V1 = C2V2/C1 plus diluent; 1:X mode gives final concentration C1/X and volumes. Unit-free algebra, pipetting safety advice (<0.5 µL suggests serial dilution), and impossible targets rejected. Sambrook & Russell / Thermo Fisher derived. Educational use only.

Education

OD600 turbidity to cells/mL (1×10⁹ per OD default) and cell dry weight g/L (0.36 per OD, BioNumbers 109837), normalized for dilution factor and path length, with total cells/CDW from the culture volume, per-cell pg CDW, and an OD > 1 linearity flag. Editable strain-specific factors. Agilent/VectorBuilder/BioNumbers derived. Educational use only.

Education

Check salt/organic-solvent contamination with A260/A230 (pure 2.0–2.2; below 2.0 = guanidinium/phenol/EDTA/salt carryover from TRIzol or columns), with an optional A260/280 cross-check. Derived from Thermo Fisher T042, Sambrook & Russell, Manchester 1995. Educational use only.

Education

Judge DNA/RNA purity from A260/A280 (pure DNA ~1.8, pure RNA ~2.0; low = protein/phenol contamination, DNA > 2.0 = RNA contamination) plus the optional A260/A230 secondary check. Derived from Manchester 1995, Sambrook & Russell, Thermo Fisher T042. Educational use only.

Development

Decode an NTP/SNTP 48-byte packet: LI/VN/Mode bitfield, stratum, poll, precision, root delay/dispersion, reference ID (with clock & kiss codes), and four 64-bit 1900-epoch timestamps

Math & Numbers

Convert moment of force (torque) between newton-metre (N·m, SI base), dyne-centimetre (dyn·cm, CGS = 10⁻⁷ N·m), pound-foot (lbf·ft = 1.3558179483314004 N·m), and kilogram-force-metre (kgf·m = 9.80665 N·m). Each factor is the exact product of the matching force factor and length factor. Converts via N·m to the target unit and lists all four equivalents. Reference: wheel-nut tightening torque ≈ 100 N·m, passenger-car engine peak torque ≈ 250 N·m.

Math & Numbers

Compute motor efficiency η = P_out / P_in. Supports electrical input (single-phase U·I·cosφ or three-phase √3·U·I·cosφ) or direct P_in; output power can be derived from a loss breakdown (copper+iron+rotor copper+mechanical+stray) or supplied directly.

Math & Numbers

Compute three-phase induction motor slip: synchronous speed n_s = 60·f/p and slip s = (n_s − n)/n_s. Supports slip-from-speed and speed-from-slip modes; automatically flags generator mode (s < 0).

Math & Numbers

Build the torque-speed curve of a three-phase induction motor using the Kloss equation T/T_max = 2/(s/s_max + s_max/s). Returns rated torque, breakdown (max) torque, starting torque, breakdown slip, and a sampled T-n curve with configurable point count.