https://smalakys.com/docs/digital_garden/Recent content in Digital Garden on Personal WebsiteHugoen-ushttps://smalakys.com/docs/digital_garden/altitude-oxygen/Mon, 01 Jan 0001 00:00:00 +0000https://smalakys.com/docs/digital_garden/altitude-oxygen/<h1 id="altitude--oxygen">Altitude &amp; Oxygen<a class="anchor" href="#altitude--oxygen">#</a></h1> <p>Enter the altitude you&rsquo;re heading to and this calculator shows the atmospheric pressure there relative to sea level. Since oxygen makes up a constant ~20.9% of dry air, that pressure ratio is also the relative amount of oxygen available per breath compared to sea level.</p> <div class="calculator" id="oxygen-calculator"> <div class="calculator-inputs"> <input type="number" id="oxygen-altitude" min="0" max="44000" step="1" value="8849" inputmode="decimal" aria-label="Altitude" /> <select id="oxygen-units" aria-label="Units"> <option value="m" selected>metres</option> <option value="ft">feet</option> </select> </div> <p class="calculator-result" aria-live="polite"> <strong id="oxygen-percent">&ndash;</strong> <span class="calculator-note">of sea-level oxygen</span> </p> <p class="calculator-detail"> Equivalent to <strong id="oxygen-fraction">&ndash;</strong> O&#8322; at sea level<br /> Pressure <strong id="oxygen-pressure">&ndash;</strong> hPa </p> </div> <h2 id="how-it-works">How it works<a class="anchor" href="#how-it-works">#</a></h2> <p>The calculator uses the International Standard Atmosphere (ISA) barometric formula. Up to the tropopause at 11 km, temperature decreases linearly with altitude and pressure follows:</p>https://smalakys.com/docs/digital_garden/stove-fuel/Mon, 01 Jan 0001 00:00:00 +0000https://smalakys.com/docs/digital_garden/stove-fuel/<h1 id="stove-fuel">Stove Fuel<a class="anchor" href="#stove-fuel">#</a></h1> <p>Estimate how much canister gas to carry from the water you need, how much comes from snow, your stove system, altitude range and reserve.</p> <div class="calculator" id="fuel-calculator"> <div class="calculator-inputs calculator-grid"> <div class="calculator-field"> <label for="fuel-people">People</label> <input type="number" id="fuel-people" min="1" max="50" step="1" value="2" inputmode="numeric" /> </div> <div class="calculator-field"> <label for="fuel-days">Days</label> <input type="number" id="fuel-days" min="1" max="120" step="1" value="5" inputmode="numeric" /> </div> <div class="calculator-field"> <label for="fuel-water">Water per person per day (L)</label> <input type="number" id="fuel-water" min="0" max="20" step="0.5" value="3" inputmode="decimal" /> </div> <div class="calculator-field"> <label for="fuel-snow">Melted from snow: <span id="fuel-snow-value">80%</span></label> <input type="range" id="fuel-snow" min="0" max="100" step="5" value="80" /> </div> <div class="calculator-field"> <label for="fuel-stove">Stove system</label> <select id="fuel-stove"> <option data-efficiency="64" value="reactor-1" selected>MSR Reactor 1.0 L</option> <option data-efficiency="71" value="reactor-17">MSR Reactor 1.7 L / 2.5 L</option> <option data-efficiency="58" value="windburner">MSR WindBurner</option> <option data-efficiency="60" value="jetboil-flash">Jetboil Flash</option> <option data-efficiency="60" value="jetboil-minimo">Jetboil MiniMo</option> <option data-efficiency="52" value="pocketrocket-screen">MSR PocketRocket 2, with windscreen</option> <option data-efficiency="42" value="pocketrocket-bare">MSR PocketRocket 2, no windscreen</option> <option data-efficiency="48" value="upright-screen">Upright canister stove, with windscreen</option> <option data-efficiency="40" value="upright-bare">Upright canister stove, no windscreen</option> <option value="custom">Custom efficiency…</option> </select> </div> <div class="calculator-field calculator-hidden" id="fuel-efficiency-field"> <label for="fuel-efficiency">Efficiency (%)</label> <input type="number" id="fuel-efficiency" min="1" max="100" step="1" value="60" inputmode="decimal" /> </div> <div class="calculator-field"> <label for="fuel-altitude">Altitude</label> <div class="calculator-pair"> <select id="fuel-altitude"></select> <select id="fuel-altitude-units" aria-label="Altitude units"> <option value="m" selected>metres</option> <option value="ft">feet</option> </select> </div> </div> <div class="calculator-field"> <label for="fuel-canister">Canister size</label> <select id="fuel-canister"> <option value="110">110 g</option> <option value="230" selected>230 g</option> <option value="450">450 g</option> </select> </div> <div class="calculator-field"> <label for="fuel-margin">Safety margin</label> <select id="fuel-margin"> <option value="0">none</option> <option value="10">+10%</option> <option value="20" selected>+20%</option> <option value="30">+30%</option> <option value="50">+50%</option> </select> </div> </div> <p class="calculator-result" aria-live="polite"> <strong id="fuel-grams">&ndash;</strong> <span class="calculator-note">of canister gas</span> </p>