Carbon/Nitrogen Ratio (C/N)
Compute the C/N ratio of an organic material by dividing the carbon content by the nitrogen content. It governs composting and decomposition: the ideal range to compost is ~25–30/1. A high ratio (straw, sawdust) breaks down slowly and immobilizes nitrogen; a low one (manure, legumes) breaks down fast and releases ammonia. Balancing 'brown' and 'green' materials starts here. Enter the carbon and nitrogen contents.
Resultado
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Relação carbono/nitrogênio (C/N)
A relação C/N é o segredo de uma boa compostagem. Os microrganismos que decompõem a matéria orgânica usam o carbono como fonte de energia e o nitrogênio para construir suas proteínas — e precisam dos dois na proporção certa: cerca de 25 a 30 partes de C para 1 de N. Materiais 'marrons' (palha, serragem, folhas secas) têm C/N alto e decompõem devagar, podendo até 'roubar' nitrogênio do solo. Materiais 'verdes' (esterco, grama, restos de comida) têm C/N baixo, decompõem rápido e podem feder a amônia. Equilibrar os dois é a arte do composto. A mesma relação governa a decomposição de restos culturais no campo. Informe os teores de carbono e nitrogênio.
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Crop Growth Rate (CGR)
Computes the crop growth rate, CGR = (W₂ − W₁) ÷ (Δt × A), the canopy's dry-matter gain per unit of ground area per day between two destructive samplings. Unlike relative growth rate, which measures efficiency per gram of existing plant, CGR measures the productivity of the LAND — it is what you compare across row spacings, seeding densities and fertiliser levels, because it answers how much biomass each square metre of field produces per day. Peak values in well-managed C4 crops fall around 20 to 30 g/(m²·day), and the integral of the CGR curve over the season is total biological yield. Enter the initial and final dry masses, the interval between samplings and the ground area sampled.
Stoichiometric Air-Fuel Ratio
Calculate the stoichiometric air-fuel ratio (AFR) by mass of a hydrocarbon C_xH_y, AFR = (x + y/4) × 137.93 ÷ M, from the number of carbon atoms x, hydrogen atoms y and the fuel molar mass M (g/mol). The result (kg air per kg fuel) is the exact amount of air needed for complete combustion, with no leftover air or fuel. Methane (CH₄) has AFR ≈ 17.2; gasoline ≈ 14.7. The 137.93 constant comes from the air mass per mole of O₂ (32 ÷ 0.232). It is the base parameter of combustion control and mixture in engines and burners. Enter x, y and the fuel molar mass.
D/d Ratio (Pulley-Rope)
Calculate the D/d ratio between the pulley diameter D and the rope diameter d, r = D ÷ d (both in the same unit). The D/d ratio is the most important parameter for the FATIGUE LIFE of a wire rope working over pulleys and drums. Each time the rope passes a pulley, it is FLEXED (bent and unbent), and this repeated bending fatigues the wires — the SMALLER the pulley diameter relative to the rope (lower D/d), the TIGHTER the curve, the greater the wire bending strain and the faster the rope fatigues and breaks. So codes require MINIMUM D/d ratios: typically 18-25 for cranes (each bend costs life), and even higher (40+) for people elevators and high-durability applications. Too small a D/d ratio drastically reduces rope life — doubling the D/d ratio can multiply rope life several times. There is a design trade-off: larger pulleys (high D/d) extend rope life but increase the equipment's size, weight and cost. The D/d ratio, with contact pressure and tension, sets the rope durability. Checking that the D/d ratio meets the code minimum is essential in designing any lifting machine. Enter the pulley and rope diameters.
Compost C:N Ratio Calculator
Divides grams of carbon by grams of nitrogen in a compost mix and says whether the pile needs more browns or more greens to sit near the ideal 25-30:1.
Worked Area per Machine
Calculate the area worked by a farm machine, A = field capacity × time, multiplying the effective field capacity (ha/h) by the available operating time (h). The result, in hectares, is how much the machine can cover in a shift — direct input for operational planning: how many hours (or days) are needed to complete the planting, spraying or harvesting of an area, and whether the machine fleet meets the agronomic window (the period in which the operation must occur). Undersizing the fleet delays critical operations and reduces yield. Enter the field capacity and the operating time.
Lens f-number by Focal and Diameter
Computes lens f-number from focal length in mm and effective entrance pupil diameter in mm using the relation N = f/D.
The results provided by this tool are for general informational and educational purposes only and do not constitute professional, financial, medical, legal, tax or accounting advice. Always confirm important decisions with a qualified professional and official sources.