Bulk terminations

Some fascinating effects occur in the case of CO on Pt(lOO). As illustrated in Fig. XVI-8, the clean surface is reconstructed naturally into a quasi-hexag-onal pattern, but on adsorption of CO, this reconstruction is lifted to give the bulk termination structure of (110) planes [56]. As discussed in Section XVIII-9E very complicated changes in surface structure occur on the oxidation of CO... 

Estimates of the landed costs of methanol (the costs of methanol deUvered by ship to a bulk terminal ia Los Angeles), vary between 8.9 and 15.6 cents per hter (33.6 and 59.2 cents per gallon). Estimates range from 7.9 to 11.1 cents per Hter (30 to 42 cents per gallon) ia a large-scale estabUshed methanol market and 11.9 to 19.3 cents per Hter (45 to 73 cents per gallon) duting a small volume transition phase (18). 

Servo Gauge. Servo gauges are high accuracy, electromechanical devices that are used on inventory control appHcations where accountabiUty is mandated for custody transfer of Hquids. The large, million barrel, bulk terminal vessels are where these devices originally found a niche. 

Figure 5 Si backscattering yiaids (anguiar scans) for normal incidance on the Si (111) (7x7) surface (solid squares) and the Si (111) [Jz x Jz) R30°-Au surface (open circies). The curve is the expected yield from a bulk terminated Si (111) surface. The scattering geometry is shown in the inset.

Figure 5.9 shows the different bulk terminations of MgO in the cubic rock salt structure. The (100) surface is by far the most stable, and MgO particles usually show only (100) facets. Note that there are two different (111) surfaces, namely those terminated by magnesium or by oxygen. Such surfaces possess a net dipole moment and are called polar. The (100) and (110) surfaces of MgO contain equal amounts of Mg and O these are neutral or nonpolar. 

In summary, the alumina nanolayers formed by the high-temperature oxidation on NiAl alloy surfaces are structurally and chemically very different from the bulk-terminated surfaces of the various A1203 phases, and they thus provide very prototypical examples of oxide phases with novel emergent properties because of interfacial bonding and thickness confinement effects. 

All Fe oxide films on Pt have strongly relaxed, unreconstructed bulk-terminated surfaces, but while the Fe304 and Fe203 oxide layers are similar to their respective bulk compounds, the ultrathin FeO layers are true 2D oxide phases that are different from the FeO bulk and stabilized by the metal-oxide interface. 

Typically at NAPL recovery sites (i.e., refineries and bulk terminals), some quantity of groundwater is coproduced. A major concern arises from this process in that the coproduced water must be treated, disposed of, or both. An evaluation process then follows on how to handle the coproduced water. A number of factors that control the ultimate fate of the water include the average volume produced on a regular basis, the level of contamination, and site-specific physical constraints. 

Reactions that occur on the surface of covalent solids have a complexity that is not as prevalent in metals. Many metal surfaces, especially the close-packed faces, retain the same geometry and bonding arrangement as would be present in the bulk phase. Most semi(x>nductor surfaces, however, undergo reconstructions in which the surface atoms move significant distances from the bulk terminated positions. For example, the Si(001) surface, if bulk terminated, would have each atom bonded to two other silicon atoms in the second layer (Fig. 7). There would be two dangling bonds each with one electron, and the... 

Fig. 7. Si(001). Bulk terminated atom positions, top and side views. (2 x 1) dimer reconstruction, top and side views. In all cases, the first-layer atoms are hatched, the second-layer atoms are shaded and deeper-layer atoms are smaller. (Drawn by Tracy Schoolcraft.)...

Another way to describe surface reconstruction is that during a reconstruction the symmetry of the surface atoms change in some way relative to their symmetry in the (relaxed) bulk terminated surface. 

From a chemical perspective, the bulk termination of Si(001) is not entirely satisfactory because each surface silicon atom has two dangling bonds associated with an unpaired electron. You can imagine that a surface atom might prefer to move into a position where unpaired electrons could pair with other unpaired electrons and form new bonds, even though doing so will... 

The studies showed asymmetric stretching of some bulk MO4 coordinated sites were UV sensitive and bulk terminal M=0 vibrations and bending... 

Many Dow operations are not directly connected with either the research laboratory or production plant. These may involve tank car and tank truck cleaning, bulk terminal operations, waste disposal facilities,... 

FIGURE 3.2. (a) Chemical structure of octanethiol. (b) A constant current STM image of octanethiol SAM on Au(l 11). Au reconstruction is lifted and alkanethiols adopt commensurate crystalline lattice characteriized by a c(4 x 2) superlattice of a (a/3 x V3)R30°. (c) Model of commensuration condition between alkanethiol monolayer (large circles) and bulk-terminated Au surface (small circles). Diagonal slash in large circles represents azimuthal orientation of plane defined by all-trans hydrocarbon chain. (Reprint with permission from Ref.25 G. E. Poirier, Chem. Rev., 97, 1117-1127 (1997). Copyright 1997 American Chemical Society.)... 

Fig. 5. Ball models of the three most densely packed surfaces of Pt. (Left) Nonrecon-structed bulk termination. (Right) Reconstructed surface (schematic).

Figure 32. Schematic drawing of OH-terminated (left), bulk-terminated (middle) and octopolar reconstructed (right) NiO(l 11) surfaces...

Bulk Terminal A facility, used primarily for the storage and/or marketing of petroleum products, which has a total bulk storage capacity of 50,000 barrels or more and/or receives petroleum products by tanker, barge or pipeline. 

Petroleum Stocks Primary stocks of crude oil and petroleum products held in storage at (or in) leases, refineries, natural gas processing plants, pipelines, tankfarms and bulk terminals that can store at least 50,000 barrels of petroleum products or that can receive petroleum products by tanker, barge or pipeline. 

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