UV-lamps

Curing section of a modern coating line with four UV lamps. (Courtesy of Prime UV Systems.) 

4 UV Curing of Coatings and Inks on Cylindrical-Shaped Parts 

This method is used for curing coatings and inks on plastic cups, tubs, tubes, or metal cans. The parts are placed on mandrels, which are attached to a rotating device. This device moves them through the individual stations feed, pretreat (most frequently corona or flame, for plastics), printing, curing, and take-off. The printing is done by dry offset (see Section 7.5.3). 

Compact and high-powered UV lamps are used to allow curing of the rotating cup directly on the mandrel. Curing times are in the range of 70 to 100 ms.  

The impression of a matte film surface is created by the diffuse reflection of light from a micro-rough surface. Such a structure is obtained by 

---

PES of neutral molecules to give positive ions is a much older field [ ]. The infomiation is valuable to chemists because it tells one about unoccupied orbitals m the neutral that may become occupied in chemical reactions. Since UV light is needed to ionize neutrals, UV lamps and syncln-otron radiation have been used as well as UV laser light. With suitable electron-energy resolution, vibrational states of the positive ions can be... 

Thymine [65-71-4] M 126.1, m 326", pK 9.82. Crystd from ethyl acetate or water. Purified by preparative (2mm thick) TLC plates of silica gel, eluting with ethyl acetate/isopropanol/water (75 16 9, v/v Rp 0.75). Spot localised by uv lamp, cut from plate, placed in MeOH, shaken and filtered through a millipore filter, then rotary evapd. [Infante et al. J Chem Soc, Faraday Trans 1 68 1586 1973.]... 

E-beam is a relatively cold process and so is more suitable for heat-sensitive substrates. UV lamps emit about one third UV light and the rest is visible and IR. Consequently substrates can get very hot, even causing fires if they become stuck beneath the lamp. Safety shutters which close if the line stops are installed on many UV bulbs. 

Some limitations are associated with UV radiation for disinfection. These include (1) The process performance is highly dependent on the efficacy of upstream devices that remove suspended solids (2) Another key factor is that the UV lamps must be kept clean in order to maintain their peak radiation output (3) A further drawback is associated with the fact that a thin layer of water (< 0.5 cm) must pass within 5 cm of the lamps. 

One way of implementing the UV disinfection process at existing activated sludge plants involves suspending the UV lights (in the form of low-pressure mercury arc UV lamps with associated reflectors) above the secondary clarifiers. The effluent is exposed to the UV radiation as it rises over the wire in a thin film. 

Fig. 7 UV hand lamps (Camag). (A) battery-powered UV lamp, (B) hand lamp with stand closed on three sides...

These restrictions do not apply to the less intense fluorescent tubes installed in the UVIS or MinUVIS (Fig. 6) or Universal UV lamps (Fig. 7). Black glass surrounds or screens serve as filters. Unfortunately account is often not taken of the fact that the transparency for short-wavelength UV light decreases appreciably with increasing duration of irradiation (Fig. 8). So it is advisable to change the filters of lamps intended for short-wavelength radiation at regular intervals. They can... 

The same UV lamps discussed in Section 2.2.3.1 are employed to excite fluorescence. Excitation is usually performed using long-wavelength radiation (2 = 365 nm), shorter wavelengths are occasionally employed (e.g. 2 = 302 nm, DNA analysis). 

Fig. 44 Apparatus for irradiation with UV light. — 1 excitation apparatus (Heraeus, Hanau OSRAM StE 501), 2 UV lamp (TNN 15-31001721), 3 housing, 4 TEC plate.

MeOH with a Hannovia UV lamp in 1973 (73TL2451). Monitoring with H NMR spectroscopy, only two among many products appeared to contain an ethoxy group. After several separations, 3-ethoxy-2-phenylindole (147, 12%), 2-phenylindole (149, 35%), and an unknown ethoxy-containing 2-phenylindole (unknown 148, 3%) were isolated (Scheme 23). 

The continuous light-water process developed by Hoechst [4] comprises five steps sulfoxidation, extract treatment, neutralization, distillation, and final treatment. Typically, the sulfoxidation proceeds in a trough-like reactor (1 in Fig. 2) of 55-m3 volume. The reactor has 40 UV lamps which are energized between 18 and 28 kW. 

The sulfoxidation of normal Cl4-CI7 paraffins with sulfur dioxide, oxygen, and water is performed under UV radiation in parallel reactors (1 in Fig. 3). The reaction enthalpy is dissipated by cooling of the paraffin in heat exchangers. The 30- to 60-kW UV lamps are cooled by a temperature-controlled water cycle. The reaction mixture leaving the reactors separates spontaneously into two phases in 2. The lighter paraffin phase is recirculated to the reactors. The composition of the heavy raw acid phase is shown in Table 5. 

For technical and safety reasons a number of other parameters must be controlled pressure of circulating gas, reactor pressure, nitrogen flow, temperature of the cooling water for the UV lamps, quantity of circulating gas and of circulating paraffin, extract level, S02 pressure, 02 pressure, S02 flow, 02 flow, off-gas flow, feed paraffin flow, feed water flow, and backwater flow. 

Eine einfache Methode ist die Reduktion mit Natriumboranat in Gegenwart katalyti-scher Mengen (0,1—0,3 Aquivalent) Trialkyl-zinnhalogenid. Die Reaktion kann durch Be-lichtung mit einer UV-Lampe beschleunigt werden7 ... 

The detector consists of a small cylindrical cell (2.0 to 10.0 pi in volume) through which flows the eluent from the column. UV light from an appropriate UV lamp passes through the cell and falls on a UV photoelectric cell. In a fixed wavelength detector the wavelength of the light... 

In the simplest form, light from a fixed wavelength UV lamp passes through a cell, through which the column eluent flows, and the fluorescent light that is emitted by a solute is sensed by a photoelectric cell positioned normal to the direction of exciting UV light. 

In photo CVD, the chemical reaction is activated by the action of photons, specifically ultraviolet (UV) radiation, which have sufficient energy to break the chemical bonds in the reactant molecules. In many cases, these molecules have a broad electronic absorption band and they are readily excited by UV radiation. Although UV lamps have been used, more energy can be obtained from UV lasers, such as the excimer lasers, which have photon energy ranging from 3.4 eV (XeF laser) to 6.4 eV (ArF laser). A typical photo-laser CVD system is shown schematically in Fig. 5.14.117]... 

Fifteen -blockers have also been activated photochemically with the same radiation unit (Heraeus, Hanau Osram STE 501 UV lamp TNN 15-3200/721)[23]. Their detection limits, the working range and associated standard deviation of the method are listed in Table 1 below. The blue fluorescence of the chromatogram zones (Xg 5 = 313 nm, > 390 nm) was measured after dipping the chromatogram in liquid paraffin - n-hexane (1 + 2). Figure 18 illustrates the separation of seven P-blockers. 

The first DNA preparations in this part of the study was PCR product - DNA of Chlamydia trachomatis 17 > bp), in the presence of a smaller by molecular mass internal control of human DNA. After migration the gel was exposured for 5, 30, 300 and 600 seconds by transilluminator Vilber Lourmat, equipped with 6 UV lamps with irradiance W = 0,24 W/m2 and 254 nm filter. The degree of structural integrity loss of amplificated DNA was evaluated by the decrease of brightness intensity of the of the bands processed by using the tools of "ImageJ" computer program. 

Tetrachlorodibenzo-p-dioxin (TCDD) (I), an occasional contaminant in 2,4,5-T and other trichlorophenol derivatives, is the most toxic of the commonly-encountered dioxins (8) and it received most of our attention. Its low solubility in common solvents and water (ca. 2 ppb) limited our experiments since the products were difficult to identify by the conventional techniques of organic chemistry. However, TCDD has an absorption maximum at 307 nm in methanol—well within the solar spectrum observed at the earth s surface and near the region of maximum intensity (310-330 nm) of the UV lamps used in previous experiments (H 29). 

Uronic acids 154,199, 322,426 Uroporphyrin 102 Ursolic acid 59, 71 UV lamps 13,14,16,137 with camera holder 13,17,136 UV absorber in plastics 281... 

Figure 1. Schematics of the fluidized bed reactor (A inlet, B UV-lamp, C Pressure gauge, D outlet).

The oxidative degradation of organic pollutants in water and air streams is considered as one of the so-called advanced oxidation processes. Photocatalytic decomposition of organics found widespread industrial interest for air purification (e.g., decomposition of aldehydes, removal of NO , ), deodorization, sterilization, and disinfection. Domestic applications based on Ti02 photocatalysts such as window self-cleaning, bathroom paints that work under illumination with room light, or filters for air conditioners operating under UV lamp illumination have already been commercialized. Literature-based information on the multidisciplinary field of photocatalytic anti-pollutant systems can be found in a number of publications, such as Bahnemann s [237, 238] (and references therein). 

---