Radiation particulate

High-energy photons (y and / yf I X rays) are the most penetrating forms of radiation. Particulate forms of radiation (a and /3 particles) are less penetrating. 

Resource availability Ecosystem diversity Human health Natural land transformation Urban land occupation Agricultural land occupation Marine eutrophication Freshwater eutrophication Water depletion Fossil depletion Metal depletion Marine ecotoxicity Freshwater ecotoxicity Terrestrial ecotoxicity Human toxicity Terrestrial acidification Ionising radiation Particulate matter formation Photochemical oxidant formation Ozone depletion Climate change L -10%... 

Alpha radiation Particulate radiation consisting of a helium nucleus emitted from a decaying a nucleus. 

Ionizing radiation Particulate radiations (alpha, electron, neutron, proton) and electromagnetic radiations (X-rays and gamma rays) that have the ability to disrupt molecular bonds (ionize) when they interact with matter. 

The terms detector, transducer, and sensor are often used synonymously, but in fact the terms have somewhat different meanings. The most general of the three terms, detector, refers to a mechanical, electrical, or chemical device that identifies, records, or indicates a change in one of the variables in its environment, such as pressure, temperature, electrical charge, electromagnetic radiation, nuclear radiation, particulates, or molecules. This term has become a catchall to the e.x-tent that entire instruments are often referred to as detectors. In the conte.vt of instrumental analysis, we shall use the term detector in the general sense in which we have just defined it. and we shall use detection system to refer to entire assemblies that indicate or record physical or chemicalquantities. An example is the UV(ultra-... 

If we think in terms of the particulate nature of light (wave-particle duality), the number of particles of light or other electi omagnetic radiation (photons) in a unit of frequency space constitutes a number density. The blackbody radiation curve in Fig. 1-1, a plot of radiation energy density p on the vertical axis as a function of frequency v on the horizontal axis, is essentially a plot of the number densities of light particles in small intervals of frequency space. 

Accuracy Under normal conditions relative errors of 1-5% are easily obtained with UV/Vis absorption. Accuracy is usually limited by the quality of the blank. Examples of the type of problems that may be encountered include the presence of particulates in a sample that scatter radiation and interferents that react with analytical reagents. In the latter case the interferant may react to form an absorbing species, giving rise to a positive determinate error. Interferents also may prevent the analyte from reacting, leading to a negative determinate error. With care, it maybe possible to improve the accuracy of an analysis by as much as an order of magnitude. 

An important question to consider when using a flame as an atomization source, is how to correct for the absorption of radiation by the flame. The products of combustion consist of molecular species that may exhibit broad-band absorption, as well as particulate material that may scatter radiation from the source. If this spectral interference is not corrected, then the intensity of the transmitted radiation decreases. The result is an apparent increase in the sam-... 

Spectroscopic measurements may also involve the scattering of light by a particulate form of the analyte, fn turbidimetry, the decrease in the radiation s transmittance through the sample is measured and related to the analyte s concentration through Beer s law. fn nephelometry we measure the intensity of scattered radiation, which varies linearly with the analyte s concentration. 

Source sampling of particulates requites isokinetic removal of a composite sample from the stack or vent effluent to determine representative emission rates. Samples are coUected either extractively or using an in-stack filter EPA Method 5 is representative of extractive sampling, EPA Method 17 of in-stack filtration. Other means of source sampling have been used, but they have been largely supplanted by EPA methods. Continuous in-stack monitors of opacity utilize attenuation of radiation across the effluent. Opacity measurements are affected by the particle size, shape, size distribution, refractive index, and the wavelength of the radiation (25,26). 

Fig. 27. Scanning electron micrograph (a) and cross-sectional comparison (b) of screen and depth filters both having a nominal particulate cut-off of 0.4 flm. The screen filter (a Nuclepore radiation track membrane) captures particulates at the surface. The phase-inversion ceUulosic membrane traps the...

X-radiation can also be induced by high energy (several Me proton beams from ion accelerators. Such particle-induced x-ray emission (PIXE) (284) is useful for thin samples and particulates, having detection Hmits of g. Intense synchrotron x-ray sources have found appHcations in... 

Radiation differs from conduction and convection not only in mathematical structure but in its much higher sensitivity to temperature. It is of dominating importance in furnaces because of their temperature, and in ciyogenic insulation because of the vacuum existing between particles. The temperature at which it accounts for roughly half of the total heat loss from a surface in air depends on such factors as surface emissivity and the convection coefficient. For pipes in free convection, this is room temperature for fine wires of low emissivity it is above red heat. Gases at combustion-chamber temperatures lose more than 90 percent of their energy by radiation from the carbon dioxide, water vapor, and particulate matter. 

Description A tray or compartment diyer is an enclosed, insulated housing in which solids are placed upon tiers of trays in the case of particulate solids or stacked in piles or upon shelves in the case of large objects. Heat transfer may be direct from gas to sohds by circulation of large volumes of hot gas or indirect by use of heated shelves, radiator coils, or refractoiy walls inside the housing. In indirec t-heat units, excepting vacuum-shelf equipment, circulation of a small quantity of gas is usually necessary to sweep moisture vapor from the compartment and prevent gas saturation and condensation. Compartment units are employed for the heating and diying of lumber, ceramics, sheet materi s (supported on poles), painted and metal objects, and all forms of particulate solids. 

VACUUM RADIATING DESORPTION AND INFRARED SPECTROMETRY (VRDIR) FOR CONTINUOUS MONITORING OF SUSPENDED PARTICULATE ORGANIC MATTERS IN ATMOSPHERE... 

Much of the concern about particulate matter in the atmosphere arises because particles of certain size ranges can be inhaled and retained by the human respiratory system. There is also concern because particulate matter in the atmosphere absorbs and scatters incoming solar radiation. For a detailed discussion of the human respiratory system and the defenses it provides against exposure of the lungs to particulate matter, see Chapter 7. 

If an ESP is 90% efficient for particulate removal, what overall efficiency would you expect for two of the ESPs in series Would the cost of the two in series be double the cost of the single ESP List two specific cases in which you might use two ESPs in series The gaseous effluent from a process is 30 m min at 65°C. How much natural gas at 8900 kg cal m would have to be burned per hour to raise the effluent temperature to 820 "C Natural gas requires 10 m of air for every cubic meter of gas at a theoretical air fuel ratio. Assume the air temperature is 20°C and the radiation and convection Iosm s are 10%. 

Studies of black-body radiation led to Planck s hypothesis of the quantization of electromagnetic radiation. The photoelectric effect provides evidence of the particulate nature of electromagnetic radiation. 

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