UV radiometer

Preparations of DNA and bacterial suspensions irradiated using a germicidal bulb (Osram, Germany) through an optical filter of 254 nm with a power light exposure of 6.7 W/m as determined by UV radiometer (TKA-PKM, Russia). 

Film samples were exposed to natural weathering conditions on an exposure rack constructed of wooden 2 X 4 s. The samples were mounted directly on a 2 X 4 facing south at an angle of 45° to the horizontal. A measure of the UV light received by the samples was originally obtained from New York State Department of Environmental Conservation (ENCON) reports, kindly supplied by Mr. William Delaware of ENCON. These reports included both total sun and sky radiation and UV radiation measured by Eppley radiometers (photometers). The ENCON monitoring station in Schenectady is within four miles of the exposure rack so no appreciable differences in light intensity should be expected. More recently, a UV radiometer has been mounted directly on the exposure rack to obtain more accurate measurements. 

Instrument manufacturers offer a variety of devices, including monitoring systems for standard process or for spot curing technology and systems for process control. Online UV radiometers can measure and display the peak intensity and total UV energy used in the process. More-advanced systems map the entire process and evaluate the lamp focus, reflector focus and reflector efficiency within a specific... 

The measuring device is Robertson-Berger broadband filter UV radiometer (RB-biometer). The time series of 10 min sums obtained during August 1, 1996 to June 25, 1997 was supplemented by (i) daily averages of total ozone concentration measured by Dobson spectrophotometer in HK [17, 18], (ii) hourly totals of global solar radiation measured by a Kipp-Zonen CP-11 in HK, and hourly fractions of sunshine... 

A complete description was presented previously (Rincon and Pulgarin 2004a). Solar ultraviolet radiation is determined by means of a global UV radiometer (KIPP ZONEN, model CUV3). Solar-UV power varies during experiments, especially when clouds are passing by. Data combination from several days and their comparison with other photocatalytic experiments is done by the application of the following equation. 

CIE Publication 53-1982 (Methods of characterizing the performance of radiometers and photometers) and CIE Publication 69-1987 (Methods of characterizing illuminance meters and luminance meters Performance, characteristics and specifications) provide detailed information on this error source and much more. CIE Division 2 TC 2-40 is currently working on an updated revision of these publications. Presently no radiometric applications have reached this level of standardization. However, both the European Thematic Network for UV Measurements (6) and the CIE TC 2-47 (Characterization and calibration methods of UV radiometers), established around 1998, (To prepare a CIE recommendation on methods of... 

The fouled surfaces of lamps and quartz sleeves are cleaned manually with a mild soap solution and then swabbed with a rag soaked in isopropyl alcohol. The transmittance of the lamps and sleeves is measured after cleaning and those that have inadequate measurements are replaced. An inventory allows the plant operator to trace the operation of individual components. Quartz sleeves should last between 4 and 7 yr, but this varies by the application site. In Teflon systems, the lamps are on removable racks and should be cleaned and monitored in the same manner as the quartz systems. The Teflon tubes should also be cleaned with mild soap and swabbed with alcohol. Each tube should be monitored for transmittance, just as with the quartz sleeves. Monitoring may not be as straightforward because of the limited accessibility to the tubes and problems in obtaining direct measurements with a UV radiometer/detector. 

Figure 2. The ratio of UV-A (380 nm) to photosynthetically active radiation (PAR, 400-700 nm) in terms of W m. Data were collected during the summer of 2001 with a UV radiometer (model Biospherical GUV-521) located at the Lacawac Sanctuary in the Pocono Mts., PA, USA (41.23 N, 75.21 W). Sunrise (5.27 h) and sunset (20.37 h) for 17 June 2001 are denoted by the vertical dashed lines. Sunrise and sunset on 8 July 2001 occurred at 5.36 h and 20.37 h, respectively. During crepuscular periods, the UVrPAR ratio is higher because the light field is mostly composed of skylight (see Section 14.1). As the sun s elevation increases, the amount of PAR increases and the light field in dominated by solar radiation. Note that a similar increase in UV-A-to-PAR occurs when patches of clouds pass over the sun. This is shown between 17.0-19.0 h on 8 July 2(X)1.

The spectral sensitivity of filter radiometers is not constant over the sensitive wavelength region. Two typical spectral sensitivities of UV radiometers are shown in Figure 5.13. The response of such radiometers depends on the measured spectral power distribution. If the calibration distribution differs from the measured distribution, a spectral mismatch must be taken into account. If the measured spectral distribution is known, the mismatch can be calculated. 

ASTM G 183 [390] Standard Practice for Field Use of Pyranometers, Pyrheliometers and UV Radiometers... 

Figure 21.4.3 shows TCE conversion and UV intensity versus illumination time at 10 SCFM for two days of operation. UV intensities were measured with a UV radiometer (UHP, San Gabriel, CA, Model UHX). TCE inlet concentrations varied from 10-15 ppmv. Detection limits for the gas chromatograph were measured at 0.5 ppmv. Figure 21.4.3 indicates that conversions greater than 95% at 10 SCFM are achieved with UV intensities at or greater than 1.5 mW/cm. At 10 SCFM, continuous destruction greater than 95% was achieved for at least 6 hours per day on two clear days in April at this latitude (37°N). The... 

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