Stacks


Stacked Seismic Traces  [c.22]

Shallow marine/ coastal (clastic) Sand bars, tidal channels. Generally coarsening upwards. High subsidence rate results in stacked reservoirs. Reservoir distribution dependent on wave and tide action. Prolific producers as a result of clean and continuous sand bodies. Shale layers may cause vertical barriers to fluid flow.  [c.79]

This procedure can be easily carried out for a set of reservoirs or separate reservoir blocks. It is especially practical if stacked reservoirs with common contacts are to be evaluated. In cases where parameters vary across the field we could divide the area into sub blocks of equal values which we measure and calculate separately.  [c.156]

In reality, aircraft parts can consist of several stacked layers of material, eonnected by rivets or bolts. To avoid corrosion, the layers are often protected by a special coating, so that there is no electrical connection between the layers. If there is a crack for example in the middle layer, no current will thus flow above or below the defect because of the insulating coating between the layers. There is only the possibility for the current to flow around the crack in the x-y  [c.259]

Right Fig. 4.2 Cross section of the test object. Comparison between the eddy eurrent density close to a crack in either a massive (bottom) or a stacked sample (top).  [c.260]

Show what the maximum possible value of is for the case of a two-dimensional emulsion consisting of uniform, rigid circles (or, alternatively, of a stacking of right circular cylinders).  [c.526]

Figure B3.3.13. Intersecting stacking faults in a fee crystal at the impact plane induced by collision with a momentum mirror for a square cross section of side 100 unit cells. The shock wave has advanced half way to the rear ( 250 planes). Atom shading indicates potential energy. Thanks are due to B Holian for tliis figure. Figure B3.3.13. Intersecting stacking faults in a fee crystal at the impact plane induced by collision with a momentum mirror for a square cross section of side 100 unit cells. The shock wave has advanced half way to the rear ( 250 planes). Atom shading indicates potential energy. Thanks are due to B Holian for tliis figure.
Figure C2.2.7. Schematic illustrating tire classification and nomenclature of discotic liquid crystal phases. For tire columnar phases, tire subscripts are usually used in combination witli each otlier. For example, denotes a rectangular lattice of columns in which tire molecules are stacked in a disordered manner (after [33]) Figure C2.2.7. Schematic illustrating tire classification and nomenclature of discotic liquid crystal phases. For tire columnar phases, tire subscripts are usually used in combination witli each otlier. For example, denotes a rectangular lattice of columns in which tire molecules are stacked in a disordered manner (after [33])
Extended defects range from well characterized dislocations to grain boundaries, interfaces, stacking faults, etch pits, D-defects, misfit dislocations (common in epitaxial growth), blisters induced by H or He implantation etc. Microscopic studies of such defects are very difficult, and crystal growers use years of experience and trial-and-error teclmiques to avoid or control them. Some extended defects can change in unpredictable ways upon heat treatments. Others become gettering centres for transition metals, a phenomenon which can be desirable or not, but is always difficult to control. Extended defects are sometimes cleverly used. For example, the smart-cut process relies on the controlled implantation of H followed by heat treatments to create blisters. This allows a thin layer of clean material to be lifted from a bulk wafer [261.  [c.2885]

P values reported for DNA electron transfer vary from 0.2 to 1.5 A Assuming that the reactions proceed by single-step tunnelling (see equation C3.2.5), explanations of the physical origin for this wide range of values include (a) the stacking interactions (Eof equation (C3.2.8 )) might be highly variable because of variations in the nature of stacking or (b) changes in the energy denominator by changes in the average energetics of the redox active donor and acceptor orbitals. An alternative explanation for small apparent p values is that the process proceeds by multistep hopping (figure C3.2.15), where many very rapid short distance steps lead to a weak apparent distance dependence. Indeed, recent experiments involving oxidation of guanine, most likely fall in the regime of either tunnelling or multistate hopping, depending upon the details of the way in which the system is constmcted.  [c.2989]

At present it is clear that the conformational dynamics of the nucleic acids (NA) is of importance for the functioning of the living cell [1]. There is a number of the conformations, spatial configurations with definite structural parameters, which NAs adopt under the wide range of the experimental conditions. These are the families of the canonical B-conformation, A-conformation, Z-conformation (ordered forms) and unordered or P-form (observed in the samples with low water content) with no base stacking and no melting when heated (for reviews see [2], [3], [4], [5]). Their appearance is dependent on the primary structure of the NA and the experimental conditions. The NA conformations are stable, but not static. The transitions between NA conformations are possible on changing of the properties of the NA surroundings such as the temperature, the ionic strength of the NA solution, the water content of the sample, etc.  [c.116]

The probability of finding a nucleic acid unit in the certain conformation according to our results is never equal to the unit. It agrees with the idea that NAs are not static but fluctuating, breathing , objects [23]. For example, in RNA molecule with 10 base pairs at the room temperature about 510 base pairs do not take part in the stacking and are not connected with H -bonds [2].  [c.122]

During processing the shot - receiver pairs are fifaf/ierecT together (they are not all acquired at the same time at each reflection point) and the effects of acquisition geometry removed before adding all the signals together stacking) to produce a single seismic trace at each surface location. Typically a trace is generated every 25m along a 2D line or every 25m in all directions in a 3D survey. The wavelet propagation through the subsurface is limited by absorption to a typical bandwidth of 10 - 60 Hz. Various processing tricks can be played to sharpen this wavelet (broadening the bandwidth) and remove noise from surface ghosts and mtv/f/p/es which, originating from near surface reflections and reverberations, tend to limit the resolving power of the method. Migration of the trace data to correct and properly focused positions in the subsurface representation is also required, and this can be done either at the end of the processing sequence or towards the beginning, before stacking. Resolution in the vertical sense, after processing, is typically of the order of 25m, but smaller scale rock property changes can be detected and Inferred during interpretation. The degree of final detail that is interpretable depends often on modelling and inversion studies based on the quality and number of well ties.  [c.20]

Deltaic (distributary channel) Isolated or stacked channels usually with fine grained sands. May or may not be in communication Good producers permeabilities of 500-5000mD. Insufficient communication between channels may require infill wells in late stage of development  [c.79]

In stacked reservoirs, such as those found in deltaic series, it is common to find that some zones are not drained effectively. Through-casing logs such as thermal neutron and gamma ray spectroscopy devices can be run to investigate whether any layers with original oil saturations remain. Such zones can be perforated to increase oil production at the expense of wetter wells.  [c.361]

The material seleeted for the production of the quasi-isotropic laminates was a prepreg material Fibredux 6376C-HTA-5-35. Specimens have a [0,+45,90,-45]s stacking sequence. The geometrical characteristics of the produced specimens are shown in Figure 1. The width is 20 mm and the thickness 1 mm. The specimens were subjected to edge polishing and aluminium end tabs were glued at the two ends of each specimen.  [c.46]

In this paper, discontinuities in cylindrical specimens were studied by ultrasonic reflection tomography. The aim was threefold. First, to localize discontinuities from circular C-scan images. Second, to reconstruct quantitative cross-sectional images from circular B-scan profiles (i.e., reflection tomograms). Finally, to obtain three-dimensional information (i.e., discontinuity location, dimension and type) by stacking these reflection tomograms in multiple planes, in the third dimension.  [c.200]

Direct three-dimensionai (or volumetric) imaging have been performed e.g. by Sire et al. [7]. In their work the whole specimen is insonified by a cone beam and reconstructed directly. In the present work the three-dimensional information was obtained by constructing two-dimensional reflection tomograms and stacking these in multiple continues planes in the third dimension, as indicated in Fig. 4. This approach needs less processing time and data storage than for direct reconstruction. Therefore, the stacking technique has been adopted for this NDE study. Once the data are mapped into a volumetric matrix composed of cubic voxels it can be numerically dissected in any plane. Fig. 4 also shows the six discontinuity types, i.e., (a)-(f) in an increasing axial distance from the edge of the 50 mm long cylinder.  [c.204]

Fig. 4. Schematic details of cylinder (left) and volumetric imaging of cylinder by stacking reflection tomograms (right). Dimensions in [mm]. Fig. 4. Schematic details of cylinder (left) and volumetric imaging of cylinder by stacking reflection tomograms (right). Dimensions in [mm].
Finally, by volumetric imaging Three-dimensional information was obtained by stacking reflection tomograms from multiple planes. Using this stacking technique, cubic voxels were obtained and could be numerically dissected in any plane. Although there are several attractive features related to this technique, there are also several questions which need to be addressed before it can be used for industrial applications. For example, the applied sound field must be further characterized.  [c.206]

D-CT-scatuiers, mainly consisting of an x-ray tube as radiation source and a fluorescent line detector, arranged as either single szintillation detectors [1] or a linear diode array [2] for converting the x-rays into visible light and taking the projection data, offer the feasibility to examine only one single slice per measurement. To obtain the samples three-dimensional structure a lot of these cuts have to be stacked upon eachother. To do so many independent time consuming measurements have to be performed.  [c.492]

For reverse engineering and rapid prototyping (RP) a special designed software package [17] is used coming from the medical field of CT investigations. These tools allow to vectorize the CT-data slice by slice semiautomatically with subpixel accuracy in the first step. Afterwards the slices can be stacked to form a volumetric dataset and transferred into the STL-format for Stereolithography (Fig. 8). Special modules for driving different RP machines are included. From the STL-Files quantitative measurements in 2D and 3D can be performed or CAD-primitives and splines can be fitted and exported as IGES-files (Fig. 7).  [c.496]

XVn). This method requires the use of a powdered sample (to have sufficient adsorption to measure), and inteiparticle capillary condensation grossly distorts the isotherms at pressures above about 0.9/ [165]. Also, of course, contact angle data are generally for a smooth, macroscopic surface of a solid, and there is no assurance that the surface properties of the solid remain the same when it is in powdered form. More useful and more reliable results may be obtained by the gravimetric method (see Chapter XVII) in which the amount adsorbed is determined by a direct weighing procedure. In this case it has been possible to use stacks of 200-300 thin sheets of material, thus obtaining sufficient adsorbent surface (see Ref. 166). Probably the most satisfactory method, however, is that using ellipsometry to measure adsorbed film thickness (Section IV-3D) there is no possibility of capillary condensation effects, and the same smooth and macroscopic surface can be used for contact angle measurements. Most of the data in Table X-2 were obtained by this last procedure the corresponding contact angles are for the identical surface. In addition to the values in Table X-2, Whalen and Hu quote 5-7 ergs/cm for n-octane, carbon tetrachloride, and benzene on Teflon [167] Tamai and co-workers [168] find values of 5-11 ergs/cm for various hydrocarbons on Teflon.  [c.370]

The otiier type of noncrystalline solid was discovered in the 1980s in certain rapidly cooled alloy systems. D Shechtman and coworkers [15] observed electron diffraction patterns with sharp spots with fivefold rotational synnnetry, a syimnetry that had been, until that time, assumed to be impossible. It is easy to show that it is impossible to fill two- or tliree-dimensional space with identical objects that have rotational symmetries of orders other than two, tliree, four or six, and it had been assumed that the long-range periodicity necessary to produce a diffraction pattern with sharp spots could only exist in materials made by the stacking of identical unit cells. The materials that produced these diffraction patterns, but clearly could not be crystals, became known as quasicrystals.  [c.1369]

True atomic resolution has been obtained on a wide range of inorganic surfaces including metals, semiconductors and insulators. Initially, imaging concentrated on Si (111) 7 x 7 as a means of demonstrating the tnie-atomic-resolution imaging capability of the teclmique [ ]. Even with such a well understood surface, surprising results were obtained in the fonu of additional contrast revealed between different surface atoms. In the case of Erlandsson et al [117] their results showed that centre adatoms appeared to be 0.13 A higher than the comer adatoms. They suggest that the additional contrast may be due to variation in chemical reactivity of the adatoms or to tip-mduced, atomic relaxation effects reflecting the stiffness of the surface lattice (figure Bl.19.25). Nakagiri et al [118] also saw additional contrast in their images of Si(l 11)7x7. Flowever, they observed the six atoms in one half of the unit cell to be brighter than in the other half The two halves correspond to faulted and unfaulted halves of the unit cell according to the dimer-adatom stacking fault model [119]. At present they are not able to distinguish which atoms correspond to which half The fact that this additional contrast varied depending on the precise experimental technique used indicates that different imaging mechanisms could be responsible as a result of the different tip material or height of the tip with respect to the surface.  [c.1701]

Figure Bl.21.1 shows a number of other clean umeconstnicted low-Miller-index surfaces. Most surfaces studied in surface science have low Miller indices, like (111), (110) and (100). These planes correspond to relatively close-packed surfaces that are atomically rather smooth. With fee materials, the (111) surface is the densest and smoothest, followed by the (100) surface the (110) surface is somewhat more open , in the sense that an additional atom with the same or smaller diameter can bond directly to an atom in the second substrate layer. For the hexagonal close-packed (licp) materials, the (0001) surface is very similar to the fee (111) surface the difference only occurs deeper into the surface, namely in the fashion of stacking of the hexagonal close-packed monolayers onto each other (ABABAB.. . versus ABCABC.. ., in the convenient layerstacking notation). The hep (1010) surface resembles the fee (110) surface to some extent, in that it also Figure Bl.21.1 shows a number of other clean umeconstnicted low-Miller-index surfaces. Most surfaces studied in surface science have low Miller indices, like (111), (110) and (100). These planes correspond to relatively close-packed surfaces that are atomically rather smooth. With fee materials, the (111) surface is the densest and smoothest, followed by the (100) surface the (110) surface is somewhat more open , in the sense that an additional atom with the same or smaller diameter can bond directly to an atom in the second substrate layer. For the hexagonal close-packed (licp) materials, the (0001) surface is very similar to the fee (111) surface the difference only occurs deeper into the surface, namely in the fashion of stacking of the hexagonal close-packed monolayers onto each other (ABABAB.. . versus ABCABC.. ., in the convenient layerstacking notation). The hep (1010) surface resembles the fee (110) surface to some extent, in that it also
Riter J R Jr 1973 Shock-induced graphite.far.wurtzite phase transformation in boron nitride and implications for stacking graphitic boron nitride J. Chem. Phys. 59 1538  [c.1962]

Since silicon is tire most important semiconductor material, clusters of silicon have been most extensively studied, botli tlieoretically and experimentally. The electronic stmcture [101, 102, 103 and 104], geometrical stmcture [105, 106, 107, 108, 109 and 110] and chemical reactivity [111] of silicon clusters have been investigated. The stmctures of small silicon clusters assume tlrree-dimensional stmctures different from botli tliat of tire bulk crystal and tliat of its group IV neighbour, carbon. Ion mobility experiments have been very effective in providing experimental stmctural infonnation for silicon clusters, and confinn tliat many stmctural isomers exist for silicon clusters because of tlieir strong covalent bonding and relatively open stmctures [106, 110]. Ion mobility results show tliat silicon clusters up to 27 atoms follow a prolate growtli sequence, resulting in geometries witli an aspect ratio of 3 [106]. Larger clusters appear to assume more spherical geometries. The stmctures of medium-sized silicon clusters witli 12-26 atoms have been studied recently by tlieoretical calculations using density functional tlieory in combination witli ion mobility experiments [110]. Figure Cl. 1.6 shows tlie calculated stmctures of silicon clusters containing 12-20 atoms. The clusters witli less tlian 18 atoms can be visualized as stacked Sig tricapped trigonal prisms, whereas global minima of Si g and Si,g assume more spherical stmctures.  [c.2396]

Figure C2.2.4. Types of smectic phase. Here tire layer stacking (left) and in-plane ordering (right) are shown for each phase. Bond orientational order is indicated for tire hexB, SmI and SmF phases, i.e. long-range order of lattice vectors. However, tliere is no long-range translational order in tliese phases. Figure C2.2.4. Types of smectic phase. Here tire layer stacking (left) and in-plane ordering (right) are shown for each phase. Bond orientational order is indicated for tire hexB, SmI and SmF phases, i.e. long-range order of lattice vectors. However, tliere is no long-range translational order in tliese phases.
Columnar phases are foniied by discotic mesogens [33], examples of which are shown in figure C2.2.6. An excellent review of molecules tliat fonii discotic phases has recently appeared [34]. Discotic molecules can fonii a nematic phase (teniied N ) just like calaniitic mesogens. In addition, several types of of columnar phase have been observed (figure C2.2.7) [35]. The recommended abbreviation for tliese phases is col [7], altliough D is often encountered, especially in tlie early literature. In tlie col. phase tliere is a disordered stacking of discotic molecules in tlie columns which are packed hexagonally. Hexagonal columnar phases where tliere is an ordered stacking sequence (colj. ) or where tlie mesogens are tilted witliin tlie columns (col ) are also known [9, 20, 34, 35 and 36].  [c.2549]

Figure C2.6.2. CSLM image of near hard-sphere silica particles of diameter d = 1050 nm witli a fluorescent core of diameter 400 nm, showing fee stacking (top), hep stacking (bottom middle) and amoriDhous areas (image size 16.3 pm X 16.3 pm, courtesy of Professor A van Blaaderen) Figure C2.6.2. CSLM image of near hard-sphere silica particles of diameter d = 1050 nm witli a fluorescent core of diameter 400 nm, showing fee stacking (top), hep stacking (bottom middle) and amoriDhous areas (image size 16.3 pm X 16.3 pm, courtesy of Professor A van Blaaderen)
One of the intriguing and beautiful properties of suspensions of well defined colloidal particles is their ability to order into a regular crystal lattice, called a colloidal crystal. The lattice spacing in colloidal crystals is set by the particle size and tends to be similar to the wavelength of light. Therefore, Bragg scattering (iridescence) can be observed using light (see section Bl. 9). Examples of this were found first in nature. For instance, tipula iridescent vims (TIV) particles were observed to assume face centred cubic (fee) stackings [71], and opals are fossilized colloidal crystals consisting of silica [72]. For further background, see [69, 73, 74]. Colloidal crystals are used as model systems to study the freezing transition. Because of their optical properties, they are also being investigated for potential applications such as optical rejection filters (for instance, [75]).  [c.2685]

Compounds and alloys of group IV elements nonnally have tire zincblende stmcture. A notable exception is SiC which can crystallize in hundreds of poly types tliat differ in tire way tire Si-C units are stacked along tire c-axis of tire crystal. For example, tire zincblende stmcture (3C) has tire sequence ABC-ABC-... witli cubic symmetry, and tire wurtzite stmcture (2H) is hexagonal witli tire sequence AB-AB-... (figure C2.16.2). The lowest-energy stmcture of SiC is 6H, witli sequence ABCACB-ABCACB-. In all tliese polytypes, each atom is fourfold coordinated and makes (almost or exactly) tetraliedral angles witli its neighbours. In addition to tire cubic and hexagonal polytypes, many otlier stmctures of SiC exist witli rhombohedral or trigonal symmetries.  [c.2878]

Although the current multithreaded implementation of sequencers works well and provides a clearly visible algorithm, threads have several drawbacks. Extra memory is required for multiple stacks, there is overhead from contextswitching between threads, and a running sequencer cannot migrate between processors along with its patch. These problems will be addressed by using the Structured Dagger coordination language [22], which enables programmers to specify partial order between entry methods of an object. Using constructs such as overlap, forall, and when-blocks, one can easily express dependencies between entry methods of an object while letting the system do the buffering, bookkeeping, etc. required for the specified flow of control.  [c.480]

Figure 9-33. Information visualization vechniques a) bar-chari (geometric display technique) b) star display (icon-based display) c) dImen Ional stacking (hierarchical displays) d) JD glyphs (hybrid technique). Figure 9-33. Information visualization vechniques a) bar-chari (geometric display technique) b) star display (icon-based display) c) dImen Ional stacking (hierarchical displays) d) JD glyphs (hybrid technique).

See pages that mention the term Stacks : [c.619]    [c.190]    [c.291]    [c.2277]    [c.2411]    [c.2547]    [c.2549]    [c.2620]    [c.2779]    [c.213]    [c.477]    [c.215]    [c.215]    [c.216]    [c.268]   
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Fundamentals of air pollution (1994) -- [ c.0 ]

Health, safety and accident management in the chemical process industries (2002) -- [ c.146 ]