Vertical profile

Etch Profiles. The final profile of a wet etch can be strongly influenced by the crystalline orientation of the semiconductor sample. Many wet etches have different etch rates for various exposed crystal planes. In contrast, several etches are available for specific materials which show Httle dependence on the crystal plane, resulting in a nearly perfect isotropic profile. The different profiles that can be achieved in GaAs etching, as well as InP-based materials, have been discussed (130—132). Similar behavior can be expected for other crystalline semiconductors. It can be important to control the etch profile if a subsequent metallisation step has to pass over the etched step. For reflable metal step coverage it is desirable to have a sloped etched step or at worst a vertical profile. If the profile is re-entrant (concave) then it is possible to have a break in the metal film, causing an open defect. 

Figure 4-344. Theoretical vertical profile for a buildup rate of 1°/10 m (37100 ft) for a well reaching horizontal. (Courtesy Inst. Fr. du Petr.)...

Figure 7-2 shows the vertical profiles of temperature, dew point, light scattering (a measure of aerosol concentration) and the concentrations of O3 and SO2. Here we see that up to about 1.5 km, the temperature, dew point, light scattering... 

Fig. 7-2 Vertical profiles of physical (temperature, dew point, and backscatter coefficient) and chemical (ozone, sulfur dioxide) variables near Scranton, PA during the afternoon of 20 July 1978. (Modified with permission from P. K. Mueller and G. M. Hidy (1982). "The Sulfate Regional Documentation of SURE Sampling Sites", EPRI report EA-1901, v. 3, Electric Power Research Institute.)...

Figure 2. Vertical profiles of temperature, nitrate, pigments, and activity ratios in the eastern...

To prevent the escape of radon from the wall surfaces, all relevant surfaces in the areas of the office, hall and sitting room were coated with an epoxy resin paint. Following application of the paint, the vertical profile of radon concentration in the internal walls was found to be more nearly constant, up to a height of 1 m. 

Vertical profiles and surface concentrations of DDT dissolved in the ocean were measured by Tanabe and Tatsukawa (1983). Water samples for depths down to 5000 m were taken on three cruises of the Ocean Research Institute, University of Tokyo and on a cruise by the University of Fisheries, Tokyo. The cruises were carried out between 1976 and 1981 in the Western Pacific, Eastern Indian and Antarctic oceans. 

Fig. 3.9 Vertical profiles of DDT concentration [ng/L] in the Pacific ocean close to Japan (A),(B), in the Indian ocean (E), and in the Antarctic ocean (F). Model results in comparison with observations from Tanabe and Tatsukawa (1983).

PFOA observations To evaluate MPI-MCTM model results observational data of PFOA from ship cruises in the Atlantic, Indian and Pacific Oceans were taken from literature (summarised in Yamashita et al (2008)). The data was collected between 2002 and 2006 in a global ocean monitoring initiative. Samples were taken from ocean surface water. Vertical profiles were sampled in the Labrador sea, the Mid Atlantic ocean, the South Pacific ocean and the Japanese sea, where water probes were done at several depths down to 5500 m. The limit of quantification for PFOA was determined as 6 pg/L. 

Vertical profiles from different ocean regions differ significantly from each other. In the Labrador Sea (Figure 3.16a) PFOA concentrations are 50 pg/L at the surface for both model results and observations. For AOl and A02 modelled profiles are almost identical, while observed profiles behave differently. Concentrations in water sample at AOl are relatively constant throughout depth, except for subsurface water, where PFOA concentration decreases, and water below 2000 m in which concentrations increase. Modelled concentrations, as well as observed ones at A02, decrease until 500 m, and remain constant down to 2000 m. In waters below 2000 m PFOA concentration increases for observations, but decreases in the model results. Yamashita et al (2008) suggest that water masses from the surface down to 2000 m were well mixed due their convective formation. The subsurface is explained... 

Model results in seawater are in good agreement with observational data of PFOA. Most differences can be attpageributed to deficiencies of the emission scenario. Despite this fact, the difference between model results and observational data are due to the limited horizontal and process resolution and the fact that the physical parameters of the model (temperature, surface pressure, vorticity or divergence of the wind velocity field) were not relaxed to observational data. Regarding these limitations, in particular individual vertical profiles compare quite well with observations. This study underlines the importance of the ocean as a transport medium of PFOA. The contribution of volatile precursor substances to long-range transport needs to be assessed. 

Dachs J, Bayona JM, Albaigs J (1997) Spatial distribution, vertical profiles and budget of organochlorine compounds in Western Mediterranean seawater. Marine Chemistry 57(3-4) 313 -324... 

Between 0.3 and 0.6 xg/l nickel was found by this method, in a vertical profile of water samples taken down to 1200 m in the Santa Catalina Basin. 

A study of the vertical profile of chlorinated solvents in the soil, enables the source of contamination to be distinguished for atmospheric inputs a peak occurred a short distance below ground, whereas for inputs from groundwater the concentration increased progressively as the water table was approached. 

Fig. 3.1.1. Vertical profile of LAS homologues in the water column in the Besaya Estuary (north of the Iberian Peninsula, Spain) (Figure taken from Ref. [8]).

The distribution of LAS in continental sediments has been studied [55], and the vertical profiles of LAS concentrations with depth in several lake sediments have been established [56,57]. In Swiss lakes, the concentration of LAS increases with depth and this is due to the efficiency of the wastewater treatment plants. Amano et al. [56] have, however, observed a decrease in the concentration of LAS with depth, and detected seasonal variations in the profile of LAS in the uppermost surface layer. 

Fig. 5.2.3. Vertical profiles of total SPC in interstitial water found at stations with different exposition grade to non-treated wastewater effluent, 0.1 km (B) and 3 km (C).

Fig. 5.2.4. Vertical profiles of nitrate and sulfate concentrations in interstitial water, and total LAS and SPC concentrations in sediment (wet weight) for station C. (Figure taken...

This stratified estuary has a depth of 40 m, with an upper fresh or brackish water layer of 0.2-4 m, depending on the river flow. The main source of pollution is untreated municipal wastewater, which is discharged into the estuary. Water samples were collected at different distances from these sewage outlets at two water depths from the fresh and the marine water layers. Furthermore, at one location, a vertical profile of the water column was made, including a sample of the water surface micro layer. Total A9PEOn, and individual AgPEOi, A9PEO2 and NP concentrations were determined with normal phase HPLC-FL analysis. 

An interesting vertical profile of the metabolite concentrations was observed the compounds showed a tendency to accumulate at the two-phase boundaries of air-freshwater and freshwater-saline water (the halocline). Thus, concentration maxima were observed at depths of 0 and 2 m (see Fig. 6.4.1) [6]. The observed distribution may result from either the physicochemical properties of these compounds (surface activity and hydrophobicity), or their formation at the interface due to increased biological activity. For the parent surfactants a similar but less pronounced vertical distribution pattern was observed (with maxima at 0 and 2 m of 17 and 9 xg L 1, respectively) [5],... 

Fig. 6.5.2. Vertical profiles obtained for LAS homologue concentrations at several sampling points from the Besaya Estuary, Spain (a) sampling site directly downstream from wastewater discharge point (b) and (c) samples taken 15 km (b) and 50 km (c) downstream from discharge (from Leon et al. [27]).

Fig. 6.5.4. Vertical profiles of LAS in sediment and interstitial waters from three stations situated at different distances from the non-treated wastewater effluent point (A 12 km B 0.1 km and C 3 km (taken from Ref. [34])).

From the foregoing discussion, it will be appreciated that sediments constitute the final natural compartment for reception of LAS that have not been degraded. The vertical profiles of the concentrations of the LAS homologues in the sediment and interstitial water found for three sampling stations are shown in Fig. 6.5.4. There is a pronounced decrease in LAS concentration with depth, particularly in the first few centimetres, which may be related to greater discharges of effluent into... 

For stations B and C, where the LAS concentrations were higher than for A, the variation in total LAS concentration with sediment depth was determined by the homologues of 12 and 13 carbon atoms (Fig. 6.5.4). These homologues present a strong tendency to sorption and are readily biodegradable. In interstitial water, the vertical profile of the LAS concentration is similar to that observed for the sediment, particularly at stations B and C. The homologue-specific partition coefficient did not vary much with depth, because there is no appreciable variation in the composition of the sediment with depth [34]. 

Fig. 6.5.5. Vertical profiles obtained for SPC homologue concentrations in several sampling points from the Besaya estuary (taken from Ref. [27]).

Parker and Lenhard (1989) and Lenhard and Parker (1988) have developed equations that relate the apparent product thickness measured at a well under equilibrium conditions with the product and water saturations in a vertical column of soils adjacent to the well. By integrating the product saturation curve with respect to elevation, an equivalent depth of LNAPL-saturated pores is obtained. This process has been implemented in a computer program called OILEQUIL. The result is reported as a total oil depth in a vertical profile. The water and oil saturation curves with elevation can also be produced and printed in graphical or tabular form. 

Fig. 18. The vertical profile of the water - ice interface at a larger magnification. Redrawn from Ref.129)...

The early Earth was probably much more geothermaUy active than the Earth is today. [122] The continents of early Earth were most likely small with vertical profiles at, or near, sea-level. [125,181] Subaerial (in addition to submarine) tectonic rift zones and hydrothermal vent fields were probably ubiquitous and vigorous. [182] Extensive continental hydrothermal zones enriched in reducing inorganic and organic vent products and subject to wet/dry cycles were probably common. The low-profile shield continents of the early Earth must have been extensively surfaced with basalt and rhyolite, [183] some of which could have been porphyritic. 

Data from GEOSECS, TTO, BATS, and HOTS and other major oceanographic research projects, such as the WOCE (World Ocean Circulation Experiment) are available online. The GEOSECS, TTO, and WOCE datasets are part of the Java Ocean Atlas, which provides a graphic exploration environment for generating vertical profiles, cross-sections, and property-property plots. Many of the data presented in this text were obtained from this source. 

---