Sterilization water

Another problem is degradation of the sensor due to the high UV dose. The radiation resistance of most photodiodes decreases with wavelengths. UV-enhanced Si photodiodes show a loss of 10% in sensitivity already after an accumulated dose of some hundred J/cm2 at X = 254 nm. This is the dose a sensor will have received over the lifetime of an Hg lamp. Special silicon nitride-protected photodiodes are stable up to 105 J/cm2. A filter combined with an attenuator may help to achieve the required selectivity and reduce the exposure of the detector. However, the radiation stability of the filter has to be guaranteed. 

So far, UV sensors have been rarely seen in households although a small proportion of the applications described can be found. Sometimes other sensing methods are used (as in flame controlling) although they are less suitable from the technological point of view or they are simply omitted (as monitoring of sunbeds). Often, the major reason is the high price of the sensor. 

Sufficiently cheap UV photodiodes are available but they are not visible-blind. Filters have to be used, but they raise the costs. Sufficiently selective photodiodes are also available but they are too expensive, mainly due to their only recently established technology. The sensor costs have been a limiting factor in two application fields of UV sensors, namely water disinfection and combustion monitoring, on the industrial as well as on the household scale. 

In communal-scale water disinfection plants, UV monitoring systems are generally included. However, for household-scale systems they are not available or only as an optional accessory. 

In power stations or other combustion units above a capacity of, say, 1 MW, UV sensors for flame monitoring are not unusual. Here, even combustion parameters like the air or fuel supply are controlled by sensing the UV emission spectrum of the flames. 

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Simultaneous application of UV and MW irradiation has found widespread use in industry. The techniques are based on the conventional UV lamps and MW-powered electrodeless lamps and MW devices [28], The following paragraphs discuss several patents and papers that describe industrial microwave photochemistry, such as treatment of waste water, sterilization, or industrial photo induced organic synthesis. 

In Chapter 5.4, optical ultraviolet radiation sensors are described, including UV-enhanced silicon-based pn diodes, detectors made from other wide band gap materials in crystalline or polycrystalline form, the latter being a new, less costly alternative. Other domestic applications are personal UV exposure dosimetry, surveillance of sun beds, flame scanning in gas and oil burners, fire alarm monitors and water sterilization equipment surveillance. 

X stock solution of isopropyl / -D-l-thiogalactopyranoside (IPTG) (0.4 m) 1 g IPTG dissolved in 10 ml bidest water sterilize by filtering through a 0.22 pm filter 1000 X stock solution of ampicillin (50 mg ml ) 1 g ampicillin dissolved in 20 ml sterilized bidest water... 

A spore suspension was prepared by resuspending the spores from the agar plate in 15 mL physiological aqueous solution (8.5 g NaCl, 1 g peptone, and 1 g Tween 80 in 1 L distilled water, sterilized at 121 °C for 20 min) with a Drigalski spatula. The spore suspension was diluted to a concentration of approximately 2.5 x lO spores/mL and stored in a 50 mL Falcon tube at 4 °C. 

Yersinia water Sterile spring water 4 446 days (1991) Karapinar and Gonul... 

Sterile distilled water Sterile screw-cap test tubes Sterile buffer (dilution blanks)... 

FVP Large volume parenterals WSP Water sterilization process... 

Cylindrical photochemical reactors placed in coaxial radiation fields are often used for carrying out photochlorination reactions, but their most important application remains in the area of water sterilization [52-54],... 

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