A Refinement Of The Determination Method Of The Linear low-pressure Uv Lamps Radiant Flux

For the measurement of linear low-pressure UV lamps radiant flux the method proposed by the IUVA, which is based on the Keitz method, has become widely used. For deriving the equation that connects the irradiance generated by a lamp at a close distance and its radiant flux, the authors of the method presume that the lamp is the cylinder of equal radiance. According to our estimates, this assumption leads to the inaccuracy of 3 % to 5 % with respect to goniophotometric measurements. In this research, a general formula is derived that connects the irradiance generated by a linear emitter and its radiant flux. This formula does not impose restrictions on the radiant intensity curve in the longitudinal plane. The Keitz equation is its particularcase. To reduce the inaccuracy of the IUVA method, the angular distribution of the radiant intensity of the UV lamps is proposed to be approximated by a cosine polynomial. In order to find the coefficients of the polynomial,clarify the Keitz formula, as well as to estimate the inaccuracy of the refined and classical versions of this formula, the series of goniophotometric measurements of the DB15, DB18, DB30 lamps at various distances was carried out. It was found that at a scanning step Δθ = 5° the first 9 terms of the trigonometric expansion are sufficient to describe the radiant intensity curve with accuracy satisfactory for practical use. It was also shown that the Keitz method needs to be refined only on the basis of goniophotometric data obtained upon condition r / l ≥ 6 where r is the test distance, l is the lamp length. It was identified that in the case of a differentiated approach, the approximation of the low-pressure UV lamps radiant intensity curve by a cosine polynomial makes it possible to provide an inaccuracy of simplified methods that does not exceed 1 % in relation to the goniophotometric method. It is in dicated that in order to find a universal factor applicable for the entire range of linear low-pressure UV lamps, the development and the analysis of statistical data is required.

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Self consistent low pressure RF (radiant flux) discharge modelling: Comparisons with experiments in clean and dusty plasmas

Pure and Applied Chemistry ◽

10.1351/pac199466061363 ◽

1994 ◽

Vol 66 (6) ◽

pp. 1363-1372 ◽

Cited By ~ 2

Author(s):

Ph. Belenguer ◽

J. P. Boeuf

Keyword(s):

Low Pressure ◽

Dusty Plasmas ◽

Radiant Flux ◽

Self Consistent

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254 nm Radiant Efficiency of High Output Low Pressure Mercury Discharge Lamps with Neon-Argon Buffer Gas

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.325-326.409 ◽

2013 ◽

Vol 325-326 ◽

pp. 409-412

Author(s):

Hao Jun Zhang ◽

Qiu Yi Han ◽

Shan Duan Zhang

Keyword(s):

Mercury Vapor ◽

Low Pressure ◽

Input Power ◽

Cold Spot ◽

Outer Diameter ◽

Buffer Gas ◽

Uv Irradiance ◽

Radiant Efficiency ◽

Uv Lamps ◽

High Output

High output low pressure mercury (LPM) discharge UV lamps have been briefly introduced. In order to measure the 254 nm radiant efficiency simply and preciously, Keitz formula was used and its advantage was illustrated. The LPM lamps had outer diameter of 19 mm (T6). The buffer gases are neon (65%) and argon (35%) with total pressure 1-10 Torr (133-1333 Pa). The lamps were operated with cold spot temperatures from 20°C to 80°C and discharge current from 0.8 A to 2.0 A. The electric field, input power, 254 nm UV irradiance and irradiance of other Hg lines from 265 to 579 nm in positive column were measured. The radiant power of each wavelength can be calibrated according to the 254 nm output and the Keitz formula. It was shown that the radiant efficiency of 254 nm can reach a maximum of above 40% at cold spot temperature 45-47 °C and current 1.6 A for filling pressure less than 3 Torr. The optimal mercury vapor pressure was 1.2 to 1.4 Pa. The output percentage of other Hg lines was below 5%. With the decrease of buffer gas pressure, the 254 nm radiant efficiency increased obviously.

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Comparison of Low Pressure and Medium Pressure UV Lamps for UV/H2O2Treatment of Natural Waters Containing Micro Pollutants

Ozone Science and Engineering ◽

10.1080/01919512.2010.508017 ◽

2010 ◽

Vol 32 (5) ◽

pp. 329-337 ◽

Cited By ~ 24

Author(s):

Guus F. IJpelaar ◽

Danny J.H. Harmsen ◽

Erwin F. Beerendonk ◽

Robin C. van Leerdam ◽

Debbie H. Metz ◽

...

Keyword(s):

Natural Waters ◽

Low Pressure ◽

Medium Pressure ◽

Uv Lamps ◽

Micro Pollutants

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Effects of UV Radiation on Photolyase and Implications with Regards to Photoreactivation following Low- and Medium-Pressure UV Disinfection

Applied and Environmental Microbiology ◽

10.1128/aem.00013-07 ◽

2007 ◽

Vol 74 (1) ◽

pp. 327-328 ◽

Cited By ~ 15

Author(s):

Jiangyong Hu ◽

Puay Hoon Quek

Keyword(s):

Uv Radiation ◽

Uv Irradiation ◽

Flavin Adenine Dinucleotide ◽

Low Pressure ◽

Uv Disinfection ◽

Medium Pressure ◽

Uv Lamps

ABSTRACT Photolyase activity following exposure to low-pressure (LP) and medium-pressure (MP) UV lamps was evaluated. MP UV irradiation resulted in a greater reduction in photolyase activity than LP UV radiation. The results suggest that oxidation of the flavin adenine dinucleotide in photolyase may have caused the decrease in activity.

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The work of rails under conditions of various average static axial loads of rolling stock

Vestnik of the Railway Research Institute ◽

10.21780/2223-9731-2018-77-3-172-176 ◽

2018 ◽

Vol 77 (3) ◽

pp. 172-176

Author(s):

M. I. Titarenko

Keyword(s):

Entire Range ◽

Static Load ◽

Statistical Data ◽

Operating Conditions ◽

Rolling Stock ◽

Axial Loads ◽

Track Maintenance ◽

Transportation Process ◽

Operational Factor

The analysis of failure of unhardened and heat-strengthened R65 rails under operating conditions in the tangent sections of the track is presented taking into account the influence of the most important operational factor - the average static axial loads of the rolling stock. Non-reinforced R65 rails in the jointed track on the 12.5 m long wooden sub-rail base were considered based on the results of their single replacement in the entire range of their failures. The work of rails under operating conditions is estimated at average static axial loads of rolling stock as 7.5, 9.5, 16.5 and 19.5 tf (73.55, 93.16, 161.82 and 191.21 kN) at all stages of the tonnage at each load. The influence of the average static axial loads of the rolling stock on rail failure in specific operating conditions has been revealed. The features of the change in the intensity of rail failure are considered at all stages of their operation, both for the specified and for the average network level of the static load. The obtained statistical data on the effect of axial loads of rolling stock on the operation of rails can be used in the practice of track maintenance. In conditions of increasing axial loads up to 25, 27 tf, it is necessary to use rails of the appropriate quality; also it is expedient to create new rails for such operating conditions. It is necessary to perform an evaluation of the real operational qualities of the rails in order to use the rolling stock with the increased axial loads (25, 27 tf) in the transportation process in the most efficient way. In the long term, the results of such studies will be aimed at improving the operation of the systems for running track and railway car complexes.

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Solar and Earth Radiation

Meteorological Measurement Systems ◽

10.1093/oso/9780195134513.003.0012 ◽

2001 ◽

Author(s):

Fred V. Brock ◽

Scott J. Richardson

Keyword(s):

Solar Radiation ◽

Physical Quantity ◽

Unit Area ◽

Solid Angle ◽

Global Solar Radiation ◽

Radiant Flux ◽

Direct Solar Radiation ◽

Radiant Intensity ◽

The Earth ◽

Earth Radiation

This chapter is concerned with the measurement of solar radiation that reaches the earth’s surface and with the measurement of earth radiation, the long wave band of radiation emitted by the earth. The unit of radiation used in this chapter is the Wm-2. Table 10-1 lists some conversion factors. Radiant flux is the amount of radiation coming from a source per unit time in W. Radiant intensity is the radiant flux leaving a point on the source, per unit solid angle of space surrounding the point, in W sr-1 (sr is a steradian, a solid angle unit). Radiance is the radiant flux emitted by a unit area of a source or scattered by a unit area of a surface in Wm-2 sr-1. Irradiance is the radiant flux incident on a receiving surface from all directions, per unit area of surface, in Wm-2. Absorptance, reflectance, and transmittance are the fractions of the incident flux that are absorbed, reflected, or transmitted by a medium. Global solar radiation is the solar irradiance received on a horizontal surface, Wm-2. This is the sum of the direct solar beam plus the diffuse component of skylight, and is the physical quantity measured by a pyranometer. Direct solar radiation is the radiation emitted from the solid angle of the sun’s disc, received on a surface perpendicular to the axis of this cone, comprising mainly unscattered and unreflected solar radiation in Wm-2. At the top of the atmosphere this is usually taken to be 1367 W m-2 ± 3% due to changes in the earth orbit and due to sunspots. The direct beam is attenuated by absorption and scattering in the atmosphere. The direct solar radiation at the earth’s surface is the physical quantity measured by a pyrheliometer. Diffuse solar radiation (sky radiation) is the downward scattered and reflected radiation coming from the whole hemisphere, with the exception of the solid angle subtended by the sun’s disc in Wm-2. Diffuse radiation can be measured by a pyranometer mounted in a shadow band, or it can be calculated using global solar radiation and direct solar radiation.

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Bromate formation from the oxidation of bromide in the UV/chlorine process with low pressure and medium pressure UV lamps

Chemosphere ◽

10.1016/j.chemosphere.2017.05.136 ◽

2017 ◽

Vol 183 ◽

pp. 582-588 ◽

Cited By ~ 40

Author(s):

Jingyun Fang ◽

Quan Zhao ◽

Chihhao Fan ◽

Chii Shang ◽

Yun Fu ◽

...

Keyword(s):

Low Pressure ◽

Medium Pressure ◽

Uv Lamps

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Inactivation differences of microorganisms by low pressure UV and pulsed xenon lamps

Water Science & Technology ◽

10.2166/wst.2003.0193 ◽

2003 ◽

Vol 47 (3) ◽

pp. 185-190 ◽

Cited By ~ 52

Author(s):

M. Otaki ◽

A. Okuda ◽

K. Tajima ◽

T. Iwasaki ◽

S. Kinoshita ◽

...

Keyword(s):

Low Pressure ◽

High Energy ◽

Suppressive Effect ◽

Uv Disinfection ◽

Xenon Lamp ◽

Survival Ratio ◽

E Coli ◽

High Turbidity ◽

The Difference ◽

Uv Lamps

UV disinfection has been applied to water treatment in recent years with low-pressure and medium-pressure UV lamps mainly used as the light source. In general, UV disinfection is considered to be inefficient with water of high turbidity because of inhibition of light penetration. Additionally, photoreactivation may be a problem that should be considered in case a disinfected water is discharged to the environment where sunlight causes reactivation. Recently, other types of lamps have been proposed including a flush-type lamp (such as a pulsed-xenon lamp) that emits high energy and wide wavelength intermittently. In this study, the difference between inactivation efficiencies by low-pressure UV (LPUV) and pulsed-xenon (PXe) lamps was investigated using two coliphage types and three strains of Escherichia coli. PXe had a suppressive effect on photoreactivation rate of the E. coli strains even though there was no significant effect on inactivation rate and maximum survival ratio after photoreactivation. PXe also had a benefit when applied to high turbidity waters as no tailing phenomena were observed in the low survival ratio area although it was observed in LPUV inactivation. This efficiency difference was considered to be due to the difference in irradiated wavelength of both lamps.

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Testing and Analysis of Characteristics of Low-Pressure Mercury and Amalgam Bactericidal UV Lamps by Various Manufacturers

Light & Engineering ◽

10.33383/2019-025 ◽

2019 ◽

pp. 112-122

Author(s):

Michael E. Allash ◽

Leonid M. Vasilyak ◽

Nikolay P. Eliseev ◽

Oleg A. Popov ◽

Dmitry V. Sokolov

Keyword(s):

High Pressure ◽

Low Pressure ◽

Russian Market ◽

Uv Lamps

The samples testing of bactericidal high-pressure UV lamps presented on the Russian Market showed their insufficient quality. These lamps were designed and manufactured based on the technical assignment of specific manufacturers or are copies of UV lamps by well-known brands but manufactured using own technology. Moreover, these devices do not comply with special aspects of UV irradiating equipment for water sterilisation such lamps may be used with by consumers.

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