Applications smoke detector

Radioisotopes have important commercial applications. For example, americium-241 is used in smoke detectors. Its role is to ionize any smoke particles, which then allow a current to flow and set off the alarm. Exposure to radiation is also used to sterilize food and inhibit the sprouting of potatoes. Radioisotopes that give off a lot of energy as heat are also used to provide power in remote locations, where refueling of generators is not possible. Unmanned spacecraft, such as Voyager 2, are powered by radiation from plutonium. 

Each of the five types of detectors listed has advantages and limitations, making each more or less suitable for an application or a specific risk. There is not a uniform performance standard for flame detectors such as their is with smoke detectors. Flame detection for a particular model has to be analyzed by evaluation of its technical specification to expected fire development. 

One of its isotopes, Am-241, is a portable source for gamma radiography also a source of ionization for smoke detectors. In the glass industry, it is used as a radioactive glass thickness gage. Other isotopes do not have much commercial application. 

An alkaline cell uses an alkaline electrolyte, with which the zinc electrode does not readily react when the battery is not in use. As a result, alkaline cells have longer lives than dry cells. The uses are the same as those for the dry cell, plus applications that require a long-lasting charge, such as smoke detectors and backup power supplies. 

CdO is used in connection with the stabilization of poly(vinyl chloride). This is discussed below in more detail. It also finds application in modifying the thermal properties of teflon and some rubbers. CdS is used in some smoke detectors, in lasers and in phosphors. The cadmium(II) halides are important as catalysts and are also used in pyrotechnics. Cadmium borates of the general type (Cd0)x(B203), are also used as phosphors. CdS04 is employed in the Weston cell, which is important as a voltage standard.137... 

The fire death rate in the United States is decreasing, dropping from a rate of 76 per million in the 1940s, when most construction and decorative products were made of natural materials, to 29 per million in the 1980s, by which time, PVC had replaced natural materials in numerous applications (189). This downward trend can be attributed in laige part to improved building codes and the broader use of sprinkler systems and smoke detectors. However, the increased use of more fire-resistant materials, such as PVC, deserves part of the credit for this improvement. 

Similar electrolytes to Li/Cl ) cell can be used. Numerous coin-cell, spiral-wound and bobbin configurations are available, as well as three-cell-in-series prismatic 9 V [27], As with most other Li metal anode primary systems, the very low self-discharge rate affords many years of shelf life in standby usage. Therefore, applications such as smoke detectors are very popular for this system. 

Radiation, from radioactive elements, has found another application that is perhaps a bit more controversial than smoke detectors— the use of radiation to kill bacteria on food. The method does work well it extends the shelf life for many foods. But some people object to using food that has been irradiated, perhaps for fear of contamination. 

MAJOR PRODUCT APPLICATIONS adhesives, caulks, sealants, inks, paints, coatings, EMI control, gaskets, decoration, plating, composites, building products, computers, pastes for electronics, stucco, arts and crafts, smoke detectors, covers, printers, copiers... 

In biomedical sensing, some of the solid-state devices based on thermal sensing cannot be used effectively. The reason is that the sensor itself has to be heated or is heated quite hot by catalytic surface reactions. Thus pellistors (oxides with catalytic surfaces and embedded platinum wire thermometer), chemiresistors, and Figaro sensor smoke detectors have not found many biologic applications. 

Not all uses of radioisotopes require securing a license. There are many commercial products, such as watch dials and other self-luminous applications, and some types of smoke detectors that contain very small quantities of radioactive materials which the owner obviously does not require a license to possess. However, those who take advantage of exemptions must use no more than the exempt quantities listed in Schedule B, 10 CFR Section 30.71. In Table 5.4, the units are in microcuries. To convert to becquerels, multiply the number given in microcuries by 37,000. 

The fascinating properties exhibited by nanoparticles, such as blue shift of the absorption spectrum, size-dependent luminescence, etc., are various manifestations of the so-called quantum confinement effect. These unique properties make ZnO a promising candidate for applications in optical and optoelectronic devices [35-38]. Polymer-based nanocomposites are the subject of considerable research due to the possibility of combining the advantages of both polymers and nanoparticles. There are several applications of polymeric nanocomposites based on their optical, electrical and mechanical properties. Further, nanocrystals dispersed in suitable solid hosts can be stabilized for long periods of time. Polystyrene (PS)— an amorphous, optically clear thermoplastic material, which is flexible in thin-film form—is often chosen as a host matrix because of its ideal properties for investigating optical properties. It is one of the most extensively used plastic materials, e.g., in disposable cutlery, plastic models, CD and DVD cases, and smoke-detector housings. 

A number of generally applicable exemption orders have been made under the Act for those situations where control would not be warranted. The orders cover such things as substances of low activity, luminous articles, electronic valves, smoke detectors and some uses of uranium and thorium. The orders should be consulted for details of the conditions under which exemption is granted. The orders are currently under review. 

Fire detectors Depending on application and property of the detector fire detectors are selected based on matching. Major types are IR fire detectors, smoke detectors, heat detectors, etc. to name a few. 

Several actinide nuclides have found other applications. Heat sources made from kilogram amounts of Pu have been used to drive thermoelectric power units in space vehicles. In medicine, Pu was applied as a long-lived compact power unit to provide energy for cardiac pacemakers and artificial organs. Am has been used in neutron sources of various sizes on the basis of the (a,n) reaction on beryllium. The monoenergetic 59-keV y radiation of Am is used in a multitude of density and thickness determinations and in ionization smoke detectors. Cf decays by both a emission and spontaneous fission. One gram of Cf emits 2.4 10 neutrons per second. "Cf thus provides an intense and compact neutron source. Neutron sources based on Cf are applied in nuclear reactor start-up operations and in neutron activation analysis. 

Radiation detectors generally complement heat and smoke detectors, especially in tall, unobstructed compartments and are effective in special applications such as flammable liquid storage areas. 

Batteries are among the most common everyday applications of chemistry. Watches and clocks, personal stereos, toys, calculators, computers, smoke detectors, and automobiles are among the many common products that rely on battery power. 

A laser based and microprocessor controlled high sensitivity spot type smoke detector. It appears similar to an ionization smoke detector. It works on the light-scattering principle but with 100 times greater sensitivity than ionization type detectors due to the use of laser. It achieves a greater sensitivity because the laser can detect extremely small products of an early fire (which cannot be seen by the human eye) therefore it is comparable in detection capability to aVESDA system (see the next section). At this time, it is considered the highest sensitivity spot type smoke detector available. Common applications include critical control and communication facilities. 

The response of beam smoke detectors is generally less sensitive to the type and color of smoke. Therefore, a beam smoke detector may be well suited to applications unsuitable for point optical smoke detectors, such as applications where the anticipated fire would produce black smoke. Beam smoke detectors do, however, require visible smoke and therefore may not be as sensitive as ion detectors in some applications. 

Underwriters Laboratories (UL). UL 268A, Standard for smoke detectors for duct application. 4th ed. Northbrook, IL UL 2009. 

Miniaturized cells are used for applications in which power consumption is tens to hundreds of microwatts. These batteries are best suited for watches, smoke detectors, temperature-monitoring sensors, and other low-power electronic components. Typical electrical performance parameters of such batteries are summarized in Table 1.13. 

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