Pyrex glass windows

Two types of plastic panels [effective size, 0.6 x 1.0 m made from poly(vinyl chloride) resin] were used for testing the sheets in polluted areas. One is the open type (the sheets are exposed to air) and the other a windowed type. The open type can simulate realistic conditions. The windowed type has a Pyrex glass window that allows the UV light to reach the sheets. The roadside air was continuously pumped to the windowed panels at 15-60 1 min-1. This type was used for estimating the amount of air coming into contacted with the materials. The air purifying materials were attached to the panels using adhesive tape. 

Useful fransparenf materials for cell windows, lenses, and so on are Pyrex glass for fhe visible and fused quartz for fhe visible and near-ulfraviolef. 

The experiments on the iodine separation were conducted as follows. A tubular vessel of pyrex glass, having at one end a plane window and at the other end a conical light-trap, was evacuated and then filled with iodine at about 0.17 mm. pressure, and then with hexene at about 6 mm. partial pressure. The tube was then subjected to the intense light from two Cooper-Hewitt glass mercury arcs, using a filter of 0.05 molal potassium dichromate 2 cm. in thickness to cut off all radiations on the violet side of the green mercury line. The lamps were rim at considerably below the rated capacity, and were cooled by a blast of air to keep the emission lines as narrow as possible. 

A system for cold vapour AAS is shown in Fig. 7.3. The evolved mercury vapour is passed to a long path-length absorption cell, usually constructed of Pyrex glass tubing with silica end windows. A transient absorption peak is observed. In some systems, a recirculating pump is used to cycle the mercury vapour around the system and achieve a steady reading. 

The gas-handling system is shown in Fig. 5. The gas cell is similar to gas cells used in infrared spectroscopy (see Exp. 37), but ordinary Pyrex glass or quartz is more suitable for windows. Suitable cells with sealed-on windows are available commercially, or cells can be made by cementing windows to the ends of a cylindrical tube that will serve... 

For the IR (Perkin-Elmer 1730 FTIR) spectroscopic studies self-supported wafers were pressed from the zeolite powder with a thickness of 15 mg/cm . The wafers were placed into a sample holder inside a pyrex glass cell with KBr windows, which allowed pretreatment (773 K, 1 hr, vacuum <10 Torr), introduction of probes, after cooling to the desired temperature, and registration of the spectra at 295 K. Three types of IR experiments were run (i) stepwise loading (0.1-6 Torr) the wafers with adsorbates at 295 K, (ii) generation of surface species with increasing temperature in the presence of adsorbate (closed cell), and (iii) loading adsorbate at 453 K followed by detection of surface species formed with time (1-240 min) at the same temperature. After each set of IR measurement the same sample was analyzed by UV-VIS spectroscopy. 

The cell was made up of PYREX glass with an optical quartz window in the front (Fig. 1). Reference and working electrode compartments were fixed on the sides. The working electrode was mounted on the cell by means of a teflon screw for ease of position adjustment. 

The transition metal ion-containing films were prepared carefully by ion-exchange as described elsewhere (10-16). These films were mounted in appropriate stainless steel or pyrex glass reactors/spectroscopic cells. Both reactors, described in detail elsewhere, had infrared (KBr) or uv-vis (quartz) transmitting windows for spectroscopic studies. They were equipped with vacuum valves for evacuation and gas admission, a heating system and a temperature monitor. 

The ferrous-exchanged zeoHte was transferred as a slurry in distilled water into a Pyrex glass Mossbauer sample cell under oxygen-free, nitrogen gas. The ceU had two very thin Pyrex windows separated by a 1 mm gap. The sample filled this gap after the excess water had been removed under vacuum. It is essential to keep the dry zeoHte free from contact with air or oxygen as some immediate oxidation to the Fe + state can occur. The thin windows of the cell aUowed some 40% transmission of the 14.4 keV y-rays to occur. The Mbssbauer spectrometer used and the complete experimental details are described in detail elsewhere [7]. 

For work with the Mg and Zn vapors, uniform vapor densities resulting in stable VUV emissions are obtained over periods of several hours with the use of double heat-pipe ovens while the heat-pipe oven for Hg vapor (Fig. 9) is a simple cell of pyrex glass. Liquid Hg and its vapor are confined to the central heated section by water-cooled jackets at each end which are tapered to return condensed Hg back to the hot zone. For generation of VUV radiation from 126 to 104.5 nm, a LiF plate a O.5 mn thick forms the exit window, and a vapor pressure of up to 95 torr is used with an equal pressure of He buffer gas. For XUV generation, X <... 

The experimental facility and instrumentation are shown in Fig. 1. The flow facility consists of a vertical 2.5 cm diameter, 15 cm long Pyrex glass test cell mounted beneath a low-pressure reservoir of volume 0.27 m. The test cell is sealed by an aluminum foil diaphragm, which is ruptured by pneumatically driven knife blades. The test cell is surrounded by a liquid-filled jacket with flat windows. This serves two purposes to eliminate the cylindrical lens effect of the test liquid (by choosing a jacket liquid with a refractive index similar to that of the test liquid) and to provide temperature control (by circulating the jacket liquid through a heat exchanger). 

Vycor and Cortex. Quartz has a very low coefficient of thermal expansion and can be cooled rapidly from high to very low temperatures. For many purposes, only the photochemical cell windows need be made of quartz and can be joined to Pyrex glass with the aid of interconnecting glass elements. For photochemical experiments in the visible region, Pyrex or soft sodium glass materials are recommended. 

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