Stainless wafers

Fig. 4.5a-c Rectangular micro-channels, (a) 4i = 133—367 pm. Test section used by Peng and Peterson (1996) (schematic view) 1 electrical contact, 2 heated stainless steel block, 5 micro-channel, 4 cover plate, (b) <4 = 404—1,923 pm. Test section used by Harms et al. (1999) (schematic view) 1 silicon wafer, 2 micro-channel, 3 heater, 4 cover plate, (c) dh = 348 pm. Test section used by Qu and Mudawar (2002a) (schematic view) 1 copper block, 2 micro-channel, 3 heater, 4 cover plate. Reprinted from Peng and Peterson (1996), Harms et al. (1999), Warrier et al. (2002), Qu and Mudawar (2002a), Gao et al. (2002), and Lee et al. (2005) with permission... 

Initially, the reactor was to be built using silicon wafers, 92 but more recent efforts have focused on a stainless steel reactor. The reformer, 7.5 x 4.5 x 11.0 cm (371 cm ), houses up to 15 stainless steel plates (0.5 mm thick) with chemically etched microchannels and heating cartridges. Conventional and laser micromachining techniques were used to fabricate the reformer body. The microchannel dimensions are 0.05 x 0.035 x 5.0 cm . The reactor inlet was carefully designed to allow uniform flow conditions. ... 

Catalyst samples were pressed as a wafer in the stainless steel or perspex sample holder. It was calculated that, due to diffusion limitations, the aqueous samples needed at least 6 hours pretreatment in order to attain monolayer coverage of the platinum with oxygen or hydrogen throughout the sample. A pretreatment time of 20 hours was chosen. 

Procedure. The rock wafers were gently cleaned three successive times with methanol in an ultrasonic bath, dried and placed in the inert atmosphere box. Two wafers of each rock type were inserted horizontally in stainless steel holders and placed in linear polyethylene containers holding 150 ml of the appropriate prepared water. The wafers were allowed to equilibrate with the water for three days and then 5 X of tracer solution was added. The resultant solutions contained V/ 5x10 M of each element. The pH of each solution was measured before and after the addition of the tracer and did not change sign-... 

The catalyst sample (approximately 130 mg, resulting in a total absorption of 2.5 after the Pt L2 edge) was pressed in a self-supporting wafer and mounted in a stainless steel in situ cell equipped with Be-windows22. Both the Pt L2 and L3 edge XAFS spectra were recorded at liquid nitrogen temperature in transmission mode. 

Al, Brass, Ag, Cu, Pt, Ni, Stainless and C-Steel, AI2O3, Fiber Tows, Glass, Graphite, LaAlOs, MgO, NAFION , NiCr, Optical Fibers, Polycarbonate, Silica, Si, Si-Ti/Pt Wafers, SiC, Si3N4, Superalloys, Teflon , Ti, TiAl alloy, YSZ. 

The reaction was carried out in a stainless-steel fixed-bed flow reactor. The zeolite powder was pressed to wafers which were subsequently crushed and sieved. Prior to reaction, the catalyst (0.4 - 0.6 mm particles) was converted in situ under vacuum to the hydrogen form by heating at a rate of 5 K/min to 675 K and then holding at 675 K for 2 hours. 

The equipment and the experimental procedures using the C02-methanol medium have already been described in previous papers. . For the photoelectrochemical experiments, a stainless steel pressure vessel was equipped with a 2-cm thick quartz window for illumination, p-type InP and GaAs wafers were cut into ca. 0.4 cm x 0.5 cm electrodes and were mounted using epoxy resin. Ohmic contact was made with successive vapor deposition of Zn (30 mn) and Au (100 nm), which was annealed afterward at 425 C in Ar. A silver wire (0.8 mm dia) was used as a quasi-reference electrode (Ag-QRE, ca. +80 mV vs. SCE). A Pt wire (0.8 mm dia) was used as the counter electrode. The photocathode was etched in hot aqua regia for ca. 5 s before each experiment. The electrolyte solution [3 cm, 0.3 mol dm" tetrabutylammonium perchlorate (TBAP) in CH3OH] was placed in a glass cell liner in the stainless steel vessel. Gases were introduced into the pressure vessel and were left to equilibrate for one hour at the desired pressure (1 to 40 atm). 

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