Nickel sampling

Figure 1 shows the expected surface temperature rise under the laser for a nickel sample and 10 MW/cm of adsorbed power. 

The catalyst powders were compressed to thin disks under a pressure of about 50 kg/cm2, with the exception of the alumina-supported catalysts which required a pressure of 1500 kg/cm2 to obtain reasonable transmittance. The samples were reduced in a stream of hydrogen supplied at a rate of 10 1 hr-1 (SV 30,000 hr-1). The temperatures of reduction were 350°-450°C for the nickel samples, 475°C for the palladium samples, and 425°C for the iridium catalysts. 

The specific metal surface area of our nickel samples was established by means of deuterium chemisorption, the amount of deuterium adsorbed being determined by exchange with a known quantity of hydrogen followed by mass speetrometric analysis. It was assumed in the calculation that 1 cm3 (NTP) of deuterium corresponds to 3.64 m2 of nickel surface area. 

Nickel concentrations from five stations in Lake Huron in 1980 had median and maximum nickel concentrations of 0.54 and 3.8 pg/L, respectively (Dolan et al. 1986). In a 1982 survey, nickel concentrations in Hamilton Harbor, Lake Ontario, ranged from <1 to 17 pg/L, with a median of 6 pg/L (Poulton 1987). The median nickel concentration from an analogous 1980 survey was 4 pg/L. Suspended sediment in surface samples (0.2 m) at Hamilton Harbor, Lake Ontario, contained 17-23 ppm nickel samples from a depth of 20 m contained 67-87 ppm, similar to the 66 ppm of nickel found in bottom sediment samples (Poulton 1987). These findings suggest that resuspension of bottom sediment is a major contributor to the suspended sediment at 20 m depth. 

The only difference between the two samples is the gold modification of the nickel nanoclusters. In these investigations, n-butane was used to test the activity, because it is known to cause the most severe graphite formation problems. Whereas the pure nickel catalyst was deactivated rapidly as a result of the formation of graphite, as confirmed by electron microscopy, for example, it was found that the conversion catalyzed by the gold/nickel sample was maintained almost constant. This comparison is consistent with the inference that the novel gold/nickel catalyst did not... 

Laboratory Methods Sample 1 Sample 2 Ni (Nickel) Sample 3... 

The surface and size of the metal particles after reduction were determined by gas chromatographic impulse titration in a flow system—for the platinum samples hydrogen-oxygen titration in nitrogen (7) was used, whereas chemisorption of oxygen in helium flow (8) was used for the nickel samples. Some samples were analyzed by electron microscopic examinations described in Ref. 9. 

The position of a nickel Auger peak superimposed on the N(ls) photoelectron peak was detected when spectra of coated nickel samples were collected on the Physical Electronics Model 5300 ESCA system using Mg Ka X-rays. Therefore, XPS spectra of nickel samples were obtained using a Surface Science Instruments SSX-100-03 instrument equipped with a monochromatic A1 Ka source. The N(ls) high-resolution spectra obtained from polished nickel which had been coated with y-APS from a 1% aqueous solution at pH 10.4 are shown in Fig. 8. 

A 1% ethanol solution (10 cm3) of salicylalaniline was treated in the reactor for 40 min at a velocity of relative sliding of 0.8 m/sec and a loading of 50 kg/cm2 using a nickel (sample)-steel (counterbody) friction pair. The green solution formed was filtered and evaporated. Yield 15%. 

Cobalt, copper and nickel metal ions were deposited by two different methods, ionic exchange and impregnation, on an amorphous silica-alumina and a ZSM-5 zeolite. The adsorption properties towards NH3 and NO were determined at 353 and 313 K, respectively, by coupled calorimetric-volumetric measurements. The average acid strength of the catalysts supported on silica-alumina was stronger than that of the parent support, while the zeolite-based catalysts had (with the exception of the nickel sample) weaker acid sites than the parent ZSM-5. The oxide materials used as supports adsorbed NO in very small amounts only, and the presence of metal cations improved the NO adsorption [70]. 

Thermal Analysis Apparatus. Mixtures to be examined by thermal analysis were contained in a nickel sample tube with a bottom well to admit the tip of the thermocouple. The sample tube was bolted through a Teflon-gasketed flange to a bellows-valve which could be attached to a vacuum manifold by a flare fitting. The volume of the sample tube was about 4.9 ml. when the valve was closed. 

A similar linear decrease in the rate of hydrogenation observed by the same workers on progressively poisoned nickel is also indicative of homogeneity of the surface. However, since the total surface area of the nickel samples employed in this study was not measured, it remains undecided whether the homogeneity applies to the total surface or to merely a part of the surface. 

Figure 1.10 REMPI-TOF permits selective simultaneous recording of separate spectra for different cluster species or for different isotopomers. The spectra of NiC and NiSi were recorded (by resonant two-photon ionization using an ArF excimer laser to ionize) using laser ablation of a nickel target in a stream of carrier gas containing 3% CH4. No intentional source of silicon was present (but the nickel sample had been roughened using SiC sandpaper) (from Brugh and Morse, 2002, and Lindholm, et al, 2003).

A study on the magnetization effects of CO adsorbed on silica supported nickel samples was carried out by Den Beston et al. (142) and,... 

The infrared data for CO adsorbed on silica supported palladium at room temperature as reported by Eischens et al. (96) is very similar to that obtained on supported nickel samples. Agreement with these results of Eischens et al. (96) has been obtained by Nash and DeSieno... 

Comparing a ceramic (porous alumina) and a metal (nickel) sample holder, Mackenzie (83) found that for the endothermic peak in kaolinite, the peak was smaller in the metal holder (about 75% that of the ceramic) and was shifted about 6% higher in temperature. 

Spectrum a of Fig. 1 is due to CO2 chemisorbed on Cab-o-sil-supported nickel at 25° and 1.2-mm pressure. The nickel sample had been reduced with Ha at 300° for 16 hrs. prior to admission of the CO2. This spectrum shows a strong band at 6.4 and a weaker band at 7.1 ft. Bands in these positions are characteristic of the carboxylate ion (2). This indicates that in the present system they are due to the structure... 

It can be seen that the activities of the amorphous alloys are lower than those of the polycrystalline catalysts. Formation of the corresponding diol was not observed on the amorphous catalysts, while the crystalline catalysts either produced the diol selectively, or a mixture of the diol and the hydroxy ketone was formed. The fundamental reason for the lower activity and higher selectivity of the amorphous alloys is their rather small surface area. Of the amorphous alloys studied, Ni-B and Ni-P alloy powders prepared by chemical reduction exhibited higher activities than those of Ni-P alloys prepared by electrolytic reduction or rapid quenching. This difference in activity can be attributed to an oxide layer covering the surface of m-P foils [Ij. It is necessary to point out, however, that the comparison of activities is based on unit catalyst weight. Obviously, this comparison does not take into account the real surface area of the nickel samples, nor active site densities. 

Krauss and Wamcke used two different calorimetric methods to determine the specific heat of high-purity nickel. The measurements in the temperature range between 180 and 600°C were carried out using a continuous calorimetric technique and between 500 and 1160°C by means of reverse calorimetry . The source of heat in the last method was a Pt-rod of known temperature and heat capacity which was placed into the calorimeter containing a nickel sample. The separation of the determined heat capacity into a lattice-vibration term, a magnetic term and a residual term was briefly discussed in this paper. The reported data were used by this review for fitting of the thermal heat capacity function for nickel crystal. 

Three alumina supported nickel samples were prepared with nickel loading ranging from 8 to 25% and dispersion varying from 10 to 28%. The surface area and the pore size of the support, the metal loading, the dispersion of the samples, deduced from hydrogen chemisorption and from magnetization curves are reported in Table 1. 

Figure 13.22 TPR profiles of a nickel sample and with 10%H2/Ar, without (a) and with water vapor (b).

Figure 9.37 illustrates the effect of molten sodium sulfate on the rate of nickel corrosion. The results show the mass change of a nickel sample, exposed to oxygen... 

Thus we are fully justified in observing that spontaneous interaction between nickel and tantalum containing chloride, chloride-fluoride, and fluoride melts results in the predominant formation of NisTa intermetallic compound on the surface of the nickel samples. This corresponds with the published thermodynamics and kinetics data for the nickel-tantalum system. 

Images of the damage on the surface of nickel samples with different structure and its alloy after corrosion tests are shown in Fig. 24. 

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