UV processing

Gomez M, Plaza E, Garralon G et al (2007) A comparative study of tertiary wastewater treatment by physico-chemical-UV process and macrofiltration-ultrafiltration technologies. Desalination 202 369-376... 

Coated substrates were cured by exposure to UV light from a Fusion Systems model F450 curing unit with a 120 w/cm (300 w/in) "DM lamp. This unit was mounted on a variable speed conveyor (4 to 75 m/min 13 to 225 ft/min) and was capable of delivering a dose of 0.12 to 2.0 J/cm2 in a single pass in air or nitrogen as measured with a UV Process Supply Compact Radiometer. 

When the source of initiation is altered from ionising radiation to UV, analogous additive effects to those previously discussed have been found. For reasonable rates of reaction, sensitisers such as benzoin ethyl ether (B) are required in these UV processes. Thus inclusion of mineral acid or lithium perchlorate in the monomer solution leads to enhancement in the photografting of styrene in methanol to polyethylene or cellulose (Table V). Lithium nitrate is almost as effective as lithium perchlorate as salt additive in these reactions (Table VI), hence the salt additive effect is independent of the anion in this instance. When TMPTA is included with mineral acid in the monomer solution, synergistic effects with the photografting of styrene in methanol to polyethylene are observed (Table VII) consistent with the analogous ionising radiation system. 

Crittenden, C Hu, S Hand, DW Green, SA. A kinetie model for H2O2/UV process in a completely mixed bateh reaetor. Water Research, 1999 33 (10), 2315-2328. 

A reactive base oligomer, which imparts most of the properties to the final cured or cross-linked material the molecular weight of oligomers used in UV processing is typically in the range from 400 to 7,000. 

The subject of EB and UV dosimetry is discussed thoroughly in Mehnert et al. The most recent discussion of radiomefric mefhods for UV processing was by J. Raymonf, "UV Measurement and Process Control/ UV/EB West 2009 Conference, Eebruary 17-18, 2009, Los Angeles (RadTech Infernafional, North America) ... 

Dose 1. In EB processing the amount of energy absorbed per unit mass, unit 1 Gray (Gy) = 1 J/kg. 2. In UV processing a common, but loosely used term for irradiant energy density or flux density at a surface of the medium of interest (unit J/cm ). 

Kinetics of Cationic Photopolymerization Chemical Systems in UV Processing... 

The subject of EB and UV dosimetry is discussed thoroughly in Reference 1. The most recent discussion of radiometric methods for UV process design and process monitoring was by R.W. Stowe at the RadTech conference 2002.17 The subject of establishing and maintaining a UV process window was discussed by J. Raymont at the same conference.18... 

For the 03/UV process Prengle (1975) has recommended the use of stirred photochemical tanks (STPR) to obtain better mass transfer. Simultaneous ozone contacting and irradiation was found to be more successful than in sequence due to the need for good ozone transfer to sustain the OH-radical reaction. A promising alternative to the STPR may be the... 

A kinetic model for H202/UV process was developed using ACUCHEM software (Yao et al., 1992). 

The application of the UV process alone showed low efficiency, which was attributed to the presence of UV-absorbing material. In addition, the photolysis of fluorene compared with the two other PAHs was significantly retarded when the fluorene was present in surface waters however, the oxidation rates of the three PAHs were essentially independent of the water type. It was concluded that the elimination of PAHs is mainly due to HO generated from hydrogen peroxide photolysis. In order to simplify the kinetic treatment, the pseudo first-order kinetics is used to determine the... 

Crittenden JC, Hu S, Hand DW, Green SA. A kinetic model for the H202/ UV process in a completely mixed batch reactor. Water Res 1999 33 2315-2328. 

FIGURE 14.1 UV processing of a 100 percent solids liquid adhesive. 

Recently, the degradation kinetics of two pharmaceutical intermediates [5-methyl-l,3,4-thiadiazole-2-methylthio (MMTD-Me) and 5-methyl-1,3,4-thiadiazole-2-thiol (MMTD)] has been studied in order to assess the effectiveness and the feasibility of UV processes. For both substrates, the results showed that no degradation occurred when H2O2 was used alone and that UV and UV/H2O2 processes were both effective for degrading the substrates, but... 

Short reviews of the recent research activities into UV disinfection of water and air and of the UV treatment techniques of polluted air are enriched by the description and discussion of several selected examples of published industrial applications. Many questions related to the selection of UV processes will be answered and common pitfalls referring to UV applications addressed. 

Unlike the H2O2-UV process the VUV oxidation of organic substrates in water (H2O-VUV) is initiated by the photochemical homolysis of water producing a series of reactive species (cf Fig.s 5-9 and 7-3, and Equations 5-18 to 5-20). In many cases water itself is the prominent absorber of VUV radiation at 172 nm (cf Ex-... 

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