Urban ecology in temperate climates. Greenhouse gas emissions include those of carbon dioxide and methane from the combustion of fossil fuels to supply energy needed by vast urban metropolises. Other greenhouse gases include water vapor, and nitrous oxide. Increases in greenhouse gases due to urban transport, construction, industry and other demands have been correlated strongly with increase in temperature. Sources of methane are agricultural dairy cows and landfills. Processes related to urban areas result in the emission of numerous pollutants, which change corresponding nutrient cycles of carbon, sulfur, nitrogen, and other elements. Ecosystems in and around the urban center are especially influenced
Nitrous oxide fuel blend Nitrous oxide fuel blend Nitrous Oxide Fuel Blend propellants are a class of liquid rocket propellants intended to replace hydrazine as the standard rocket fuel. The fuel and oxidizer are blended and stored; this is sometimes referred to as a "mixed monopropellant". Upon use, the propellant is heated or passed over a catalyst bed and the nitrous oxide decomposes into oxygen-rich gasses. Combustion then ensues. Special care is needed in the chemical formulation and engine design to prevent detonating the stored fuel. The agent used for rocket fuel in a shuttle is paramount; weight, thrust, cost, toxicity, risk of explosions