Definitions - r

Rapid growth and occupation through early reproduction, short life spans, low biomass, and lots of offspring. See K-Selection.

The R value or R-value is a measure of thermal resistance used in the building and construction industry. The bigger the number, the better the building insulation's effectiveness. R value is the reciprocal of U-value. Often used as a measure of bulk insulation products, such as a roof insulation Batts.

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A device designed to reduce or stop the flow of radiant energy.

A heating system that warms the floor, which radiates heat to the whole house. Often either electrical or hot water based.

An increase in temperature with height due to radiational cooling of the earth's surface. Also called a nocturnal inversion.

A change in the balance between incoming solar radiation and outgoing infrared radiation. Without any radiative forcing, solar radiation coming to the Earth would continue to be approximately equal to the infrared radiation emitted from the Earth. The addition of greenhouse gases traps an increased fraction of the infrared radiation, radiating it back toward the surface and creating a warming influence.

An area of diminished precipitation on the lee (downwind) side of a mountain or mountain range.

Rainwater harvesting refers to the act of 'keeping' rainwater that falls on your roof for use later. This implies that the a certain amount of plumbing is done to collect the water to a central tank, then plumbing is done to provide the water where needed. Also overflow plumbing needs to be done for when the tank is full.

This is often done to reduce a building's dependence on piped 'town water' or to provide fresh water where town water is not available. The water so collected is suitable for drinking as long the roof is clean and the water tank is rated for potable water storage.

See here for an online calculator to work out the amount of water you can harvest and the size of tank you need in relation to your water usage.

Greenhouse gases are those gaseous constituents of the atmosphere, both natural and anthropogenic, that absorb and emit radiation at specific wavelengths within the spectrum of thermal infrared radiation emitted by the Earth’s surface, the atmosphere itself, and by clouds. This property causes the greenhouse effect.

Greenhouse gases are essential to maintaining the current temperature of the Earth; without them the planet would be uninhabitable.

Wikipedia Entry

Rapidly renewable materials include those that replenish faster than hardwoods. Bamboo and cork fall into this category.

Reused heat or energy that otherwise would be lost. For example, a combined cycle power plant recaptures some of its own waste heat and reuses it to make extra electric power.

Fragments of products or finished products of a manufacturing process, which has converted a resource into a commodity of real economic value, and includes pre-consumer and post-consumer material but does not include excess resources of the manufacturing process.

Greenhouse gases are those gaseous constituents of the atmosphere, both natural and anthropogenic, that absorb and emit radiation at specific wavelengths within the spectrum of thermal infrared radiation emitted by the Earth’s surface, the atmosphere itself, and by clouds. This property causes the greenhouse effect.

Greenhouse gases are essential to maintaining the current temperature of the Earth; without them the planet would be uninhabitable.

Wikipedia Entry

The redox (reduction–oxidation) cell is a reversible cell in which electrochemical components are dissolved in the electrolyte. Redox flow batteries are rechargeable.

Greenhouse gases are those gaseous constituents of the atmosphere, both natural and anthropogenic, that absorb and emit radiation at specific wavelengths within the spectrum of thermal infrared radiation emitted by the Earth’s surface, the atmosphere itself, and by clouds. This property causes the greenhouse effect.

Greenhouse gases are essential to maintaining the current temperature of the Earth; without them the planet would be uninhabitable.

Wikipedia Entry

A product that has been completely disassembled and restored to its original working order while maximizing the reuse of its original materials.

Regenerative braking is a system that converts kinetic energy (energy of motion) back into electricity when a vehicle slows down or brakes. This captured energy is then stored in the battery for later use, effectively increasing the vehicle's range and efficiency. In electric and hybrid vehicles, the electric motor is used as a generator, turning it into a way to recover energy that would otherwise be lost as heat. 

Ability of an ecosystem to maintain relative ecological integrity indefinitely.

Relative humidity is a term used to describe the amount of water vapor in a mixture of air and water vapor. It is defined as the partial pressure of water vapor in the air-water mixture, given as a percentage of the saturated vapor pressure, under those conditions

The relative humidity of air thus changes not only with respect to the absolute humidity (moisture content) but also temperature and pressure, upon which the saturated vapor pressure depends. Relative humidity is often used instead of absolute humidity in situations where the rate of water evaporation is important, as it takes into account the variation in saturated vapor pressure.

Any product diverted from the supply of discarded materials by refurbishing and marketing said product without substantial change to its original form.

Greenhouse gases are those gaseous constituents of the atmosphere, both natural and anthropogenic, that absorb and emit radiation at specific wavelengths within the spectrum of thermal infrared radiation emitted by the Earth’s surface, the atmosphere itself, and by clouds. This property causes the greenhouse effect.

Greenhouse gases are essential to maintaining the current temperature of the Earth; without them the planet would be uninhabitable.

Wikipedia Entry

Fish species that complete their entire life cycle in freshwater. Non-anadromous fish. An example is rainbow trout.

Greenhouse gases are those gaseous constituents of the atmosphere, both natural and anthropogenic, that absorb and emit radiation at specific wavelengths within the spectrum of thermal infrared radiation emitted by the Earth’s surface, the atmosphere itself, and by clouds. This property causes the greenhouse effect.

Greenhouse gases are essential to maintaining the current temperature of the Earth; without them the planet would be uninhabitable.

Wikipedia Entry

A practice in which the primary consideration of material use begins with the concept of "Reduce - Reuse - Recycle - Repair" stated in descending order of priority.

This concept may be applied in everyday life to help promote a sustainable society. In design, begin by reducing the amount of material that is specified; find ways to reuse materials, recycle products or product waste; specify products made from recycled materials; and repair or restore products instead of replacing them.

The heating of oil shale to get the oil out from it.

Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds. There are three naturally occurring isotopes, with 12C and 13C being stable, while 14C is radioactive, decaying with a half-life of about 5730 years. Carbon is one of the few elements known since antiquity. The name "carbon" comes from Latin language carbo, coal.

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Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds. There are three naturally occurring isotopes, with 12C and 13C being stable, while 14C is radioactive, decaying with a half-life of about 5730 years. Carbon is one of the few elements known since antiquity. The name "carbon" comes from Latin language carbo, coal.

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An area of land directly influenced by water. An ecosystem that is transitional between land and water ecosystems. Riparian areas usually have visible vegetative or physical characteristics reflecting the influence of water. River sides, lake borders, and marshes are typical riparian areas.

Riparian areas that are managed to protect the aquatic and riparian ecosystem. A riparian buffer protects water quality and temperature, habitat along the banks, upland habitat for aquatic and riparian species, and some or all of the floodplain.

The rights of water use possessed by a person owning land containing or bordering a water course or lake.

A rotating, cigar-shaped cloud that sometimes precedes a thunderstorm. Often seen in UFO photographs.

Fish not prized for sport or eating, such as gar and suckers. Most are more tolerant of changing environmental conditions than are game or food species.