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What is mean radiant temperature?
The mean radiant temperature is the average effect of radiation from surrounding surfaces. At the center of the room this temperature can be taken as being equal to the mean surface temperature
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A Radiant Barrier is... . A radiant barrier is a thin sheet of highly reflective aluminum comprised of one or more layers (for puncture and tear resistance) that, when inst…alled properly, will block at least 90% of the radiant heat that hits it. Radiant barriers are unaffected by humidity or ambient temperatures, unlike other forms of insulation, and therefore perform at a consistent level at all times. When installed in an attic, a radiant barrier reflective foil insulation products can reduce attic temperatures by up to 30 degrees when installed to the underside of roof rafters. Lowering attic temperatures provides a significant benefit by reducing air conditional loads and energy usage. Attic insulation radiant barriers can also: . Reduce heat transfer from attic to living spaces by up to 50%,. Extend the life of air conditioning units, and. Increase the comfort level of a home.. Radiant Barrier Definition : Per the Department of Energy (DOE), a product classified as a "radiant barrier" must have a low emittance of 10% or less and high reflectance of 90% or more. . Emittance (or emissivity), refers to the ability of a material's surface to emit radiant energy. All materials have emissivities ranging from 0% to 100%. The lower the emittance of a material, the lower the heat (infra-red radiant energy) radiated from its surface. Aluminum foil has a very low emittance, which explains its use in reflective insulation and radiant barriers.. Reflectance (or reflectivity) refers to the fraction of incoming radiant energy that is reflected from the surface. Reflectivity and emissivity are related and a low emittance is indicative of a highly reflective surface.. RadiantGUARDÂ® radiant barrier products BLOCK 97% of the radiant heat - much higher than the DOE minimum reflectance criteria for a radiant barrier product.
Anything that is not at absolute zero (0 K, i.e. everything) willemit radiant energy. Radiant energy is caused by electronconfiguration changes within the substance, whether i…t be liquid,solid, or gas. It is transported between objects viaelectromagnetic waves, which means that it does not require anymatter between the two objects in order to transfer energy.Examples would be the sun emitting radiation to the earth throughspace, or a radio antenna emitting radiation to your car's stereo.There doesn't need to be air between the antenna and your car inorder for you to pick up a signal. Radiate Energy can be carried by light too! Radiation Transfers Energy Energy can be transferred even though there are no particles totransfer the energy. This type of energy transfer is calledradiation. Energy that is transferred in this way is called radiantenergy or electromagnetic radiation (EMR for short). Radiant energy travels in waves (much like a tsunami). These waves can travel through space, air, glass and many othermaterials. There are different forms of EMR, including radio waves,microwaves, visible light and X-rays. If the energy source is a warm object, like the sun, some of thethermal energy is transferred as a type of EMR called infraredradiation (IR) or 'heat radiation'. Properties (characteristics) of Radiant Energy are: Waves of radiant energy can travel in a vacuum. All waves travel, across empty space, at an extremely high speed(300 Million m/s). Radiant energy travels in a straight line. they behave like waves they can be absorbed and reflected by objects All kinds of radiant energy interact with matter: Reflection occurs if the energy cannot penetrate the surface of thematerial it comes into contact with. Absorption occurs if the energy penetrates part way into theobject. Transmission occurs if the energy penetrates completely, passingthrough the object with no absorption of energy. Absorbing / Emitting Energy Dull dark objects absorb radiant energy when they arecool, and emit radiant energy when they are hot. (eg. asphaltsidewalk) Light, shiny objects or surfaces do not absorb radiant energyreadily and do not emit radiant energy readily. (eq. ice surface) Radiant emission of energy from the body depends on surface area(smaller areas help to retain heat, whereas, larger areas radiateheat). This is evident in the adaptations of many species ofanimals who have successfully adapted to their environments.(desertanimals - eg. Fox p. 140) (killer whales-The killer whale'sfusiform body shape and reduced limb size decreases the amount ofsurface area exposed to the external environment. This helps killerwhales conserve body heat.) The polar bear has black skin to absorbradiant energy with transparent hair that transmitts ultravioletradiation to the skin. Most radiation (82%) people are exposed, to comes from naturalsources. By far the largest source is radon, an odorless, colorlessgas given off by natural radium in the Earth's crust. Artificialradiation, mostly from medical uses and consumer products, accountsfor about eighteen percent of our total exposure. The nuclearindustry is responsible for less than one percent. Radiation can be detected, measured and controlled. The measurement of radiation is by the amount ofradioactivity present or the amount of radiant energy given off. Radiation in the Environment Radiation is a natural part of our environment. Humanshave always lived on earth in the presence of radiation. Naturalradiation reaches earth from outer space and continuously radiatesfrom the rocks, soil, and water on the earth. Background radiationis that which is naturally and inevitably present in ourenvironment. Levels of this can vary greatly. People living ingranite areas or on mineraliscd sands receive more terrestrialradiation than others, while people living or working at highaltitudes receive more cosmic radiation. A lot of our naturalexposure is due to radon. a gas which seeps from the earth's crustand is present in the air we breathe.
Temperature is defined as the average total kinetic energy per particle in a system. In common terms, it means how hot or cold something is or feels, usually expressed as rela…tive to an arbitrary point (e.g. water freezes at 0oC and this is normally called a "cold" temperature; the human body is around 37oC and this is sometimes considered "warm" or "hot"). Temperature is the measure of hotness expressed in terms of any of several arbitrary scales, such as Fahrenheit, Celsius, or Kelvin. "Heat flows from a hotter body to a colder one and continues to do so until both are at the same temperature. Temperature is a measure of the average energy of the molecules of a body, whereas heat is a measure of the total amount of thermal energy in a body."
It means that something or someone is so bright and shiny that they radiate light. The word radiant usually means something that has a very bright light, radium is nam…ed because it gives light.
The meaning of temperture is it measures how hot or cold matter is.
A pyrometer or pyrometric cones are used to measure furnace and kiln temperatures resulting from radiant heat. A pyrometer is a ceramic base into which 4 to 6 pyrometric cones…, which melt at different temperatures, are inserted. Placing this into a furnace opening which is out of the normal gas passes, in direct view of the flame, and can be sealed from in-leakage of cooler air, will give you a general idea of a flame temperature (radiant heat). If it is inserted into a gas pass it will give convective heat temperatures. By knowing the temperature at which each cone melts you can get a close approximation of a flame or furnace temperature. More modern line of sight infrared-laser thermal imaging guns can give direct readings of surface or flame temperatures, and are more accurate. Thermocouples though must be used in convective gas passes.
The wavelength of radiation is related to the frequency of radiation. Frequency is the rate of vibration of a wave source. High frequency vibrations produce short waves and lo…w frequency vibrations cause longer waves. A low temp. source emits primarily low-frequency, long-wavelength waves. A high temp. does just the opposite.
A comet's radiant is made up of a frozen mass of dust and gas. It revolves around the sun and radiates light.
It means that you have a fever and that your temperature is not normal.
The radiant girls were a group of girls hired to paint glow-in-the-dark numerals on watches in the mid 1920's, they were told to keep the paint brushes pointy by licking them …after every stroke, what they didn't know was that the chemicals in the glow-in-the-dark paint was harmful if ingested slowly all of the radiant girls began to fall ill with bone cancer and eventually deceased
Mean in this case is another word for average. The average temperature for a certain month.
To develop a permanently radiant personality one must form the habit of being permanently happy.
It means a smile that seems to shine.
The answer to this is given by Wien's displacement law, at least for an ideal "black body" as the radiating source. The law states that the distribution of wavelengths has es…sentially the same shape at all temperatures (with the scale varying), with the peak wavelength λpeak occuring at: λpeak = b/T, where b is Wien's displacement constant and T is the absolute temperature. In S.I. units, b = 2.898×10−3 m·K to four significant figures (the unit is metre-Kelvin, not millikelvin).