MULTIPLE REFLECTION PROBLEMS IN WESTERN CANADA

Geophysics ◽  
1963 ◽  
Vol 28 (5) ◽  
pp. 882-893 ◽  
Author(s):  
Stanley A. Mouritsen
Keyword(s):  
Cross Sections ◽  
Multiple Reflection ◽  
The Other ◽  
Western Canada ◽  
Multiple Reflections ◽  
Oil Companies ◽  
Reef Structure ◽  
Seismic Records

The purpose of this paper is to stimulate interest in the problems of sedimentary multiple reflections in Canada and to show examples of some of the existing types. The types considered are: Second White Specks to the Paleozoic surface, the Blairmore to the Paleozoic surface, the suspected Ireton or base of the Nisku to the Paleozoic surface, the Devonian to the Paleozoic surface, and the base‐of‐weathering to the Paleozoic surface. Record examples were contributed by oil companies in Calgary to illustrate the Cretaceous‐to‐Paleozoic surface and the base‐of‐weathering‐to‐Paleozoic‐surface types. Records showing the other types are classified as confidential and unavailable. The base‐of‐weathering‐to‐Paleozoic‐surface multiple is shown with supporting cross‐sections and record‐sections as well as the simple field procedure, based on known data, that can be used by the field interpretation staff to help confirm this type of multiple. The problem of correctly interpreting seismic records where multiple reflections are present is discussed, and the criteria for distinguishing between multiple anomalies and true structures (particularly reef structure) presented. The conclusions drawn from the discussion are that for most types of multiple reflection interference accurate interpretations can be made. However, multiple reflections in certain areas can make definite interpretive results impossible.

SOME EXPERIMENTS ON MULTIPLE REFLECTION CANCELLATION

Geophysics ◽  
1965 ◽  
Vol 30 (6) ◽  
pp. 1085-1093 ◽  
Author(s):  
Daniel Silverman ◽  
N. R. Sparks
Keyword(s):  
Noise Level ◽  
Multiple Reflection ◽  
Multiple Reflections ◽  
Near Surface ◽  
High Noise ◽  
Precise Information ◽  
High Noise Level ◽  
The Earth ◽  
Primary Signal ◽  
Seismic Records

One of the most promising methods of identification or cancellation of multiple reflections on seismic records involves the calculation of synthetic records with all primaries and multiples, and the matching of the synthetic record with the field record. Such matching suffers today from the lack of precise information about the velocities and densities of the formations, dips of beds nonvertical transmission, etc. One possibility of improving this match involves the use of the earth itself as the “synthetic record computer.” In this process, the upcoming (or downgoing) primary signals are fed back into the earth with a vibrator in proper amplitude and phase to create a synthetic record of multiples only, which should match the multiples on the field record. Of course, only those multiple reflections which include a downward reflection from beds above the primary signal detectors will be included in the synthetic record of multiples only. The paper reports two experimental programs. One was carried out on an analog network to simulate the near‐surface and deeper formations, with means to feed back the upcoming signals in proper timing and polarity to cancel the multiples. These experiments indicated the theoretical workability of the process. The second program of experiments involved the use of a vertical spread to detect the upcoming and downgoing signals, and the use of a hydraulic vibrator to impress those signals back into the earth. These experiments were not conclusive because of insufficient power in the vibrator and high noise level. However, they indicated possible ways in which these limitations might be reduced, and the method applied to routine field operations.

Electron Irradiation Effects in Polyoxymethylene Crystals Grown Inside Trioxane Crystals

1971 ◽  
Vol 29 ◽  
pp. 78-79
Author(s):  
J. P. Colson ◽  
D. H. Reneker
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Detailed Examination ◽  
The Other ◽  
Electron Micrograph ◽  
Irradiation Effects ◽  
Threefold Axis ◽  
Typical Sample ◽  
Polymer Crystals ◽  
Chain Axis

Polyoxymethylene (POM) crystals grow inside trioxane crystals which have been irradiated and heated to a temperature slightly below their melting point. Figure 1 shows a low magnification electron micrograph of a group of such POM crystals. Detailed examination at higher magnification showed that three distinct types of POM crystals grew in a typical sample. The three types of POM crystals were distinguished by the direction that the polymer chain axis in each crystal made with respect to the threefold axis of the trioxane crystal. These polyoxymethylene crystals were described previously.At low magnifications the three types of polymer crystals appeared as slender rods. One type had a hexagonal cross section and the other two types had rectangular cross sections, that is, they were ribbonlike.

NOTES ON MULTIPLE REFLECTIONS

Geophysics ◽  
1948 ◽  
Vol 13 (1) ◽  
pp. 55-56
Author(s):  
Dean Walling
Keyword(s):  
Multiple Reflection ◽  
Large Percentage ◽  
Multiple Reflections ◽  
Reflection Theory ◽  
Proper Interpretation

Since the inception of the reflection seismograph, apparent reflections have been observed from time to time, which for one reason or another, do not meet the requirements of normal reflections from interfaces in the sedimentary section. Various theories have served to explain and allow the proper interpretation of a large percentage of these spurious energies. Among these is the multiple‐reflection theory which has proven to be applicable in many cases.

scholarly journals Comment on "Radiative forcings for 28 potential Archean greenhouse gases" by Byrne and Goldblatt (2014)

2015 ◽  
Vol 11 (8) ◽  
pp. 1097-1105 ◽  
Author(s):  
R. V. Kochanov ◽  
I. E. Gordon ◽  
L. S. Rothman ◽  
S. W. Sharpe ◽  
T. J. Johnson ◽  
...  
Keyword(s):  
Greenhouse Gases ◽  
Cross Sections ◽  
Spectral Region ◽  
Radiative Forcing ◽  
Recent Article ◽  
The Other ◽  
Radiative Forcings ◽  
The Status ◽  
Moderate Resolution ◽  
Spectroscopic Database

Abstract. In the recent article by Byrne and Goldblatt, "Radiative forcing for 28 potential Archean greenhouse gases", Clim. Past. 10, 1779–1801 (2014), the authors employ the HITRAN2012 spectroscopic database to evaluate the radiative forcing of 28 Archean gases. As part of the evaluation of the status of the spectroscopy of these gases in the selected spectral region (50–1800 cm−1), the cross sections generated from the HITRAN line-by-line parameters were compared with those of the PNNL database of experimental cross sections recorded at moderate resolution. The authors claimed that for NO2, HNO3, H2CO, H2O2, HCOOH, C2H4, CH3OH and CH3Br there exist large or sometimes severe disagreements between the databases. In this work we show that for only three of these eight gases a modest discrepancy does exist between the two databases and we explain the origin of the differences. For the other five gases, the disagreements are not nearly at the scale suggested by the authors, while we explain some of the differences that do exist. In summary, the agreement between the HITRAN and PNNL databases is very good, although not perfect. Typically differences do not exceed 10 %, provided that HITRAN data exist for the bands/wavelengths of interest. It appears that a molecule-dependent combination of errors has affected the conclusions of the authors. In at least one case it appears that they did not take the correct file from PNNL (N2O4 (dimer)+ NO2 was used in place of the monomer). Finally, cross sections of HO2 from HITRAN (which do not have a PNNL counterpart) were not calculated correctly in BG, while in the case of HF misleading discussion was presented there based on the confusion by foreign or noise features in the experimental PNNL spectra.

Reactions of hydrogen atoms with hexafluoroacetone

1978 ◽  
Vol 56 (20) ◽  
pp. 2638-2645 ◽  
Author(s):  
D. W. Grattan ◽  
K. O. Kutschke
Keyword(s):  
Rate Constant ◽  
Cross Sections ◽  
The Other ◽  
Hydrogen Atoms ◽  
Kinetics Of

Attempts were made to study the kinetics of the reaction of atomic H with (CF3)2CO vapour (HFA). Atomic H was generated from H2 by mercury photosensitization in the presence of C2H4 and HFA but the system was complicated by the loss of C2H5 radicals by addition to HFA and the kinetic results were intractable. When atomic H was generated from C3H8, the kinetics again were obscured by some unidentified reaction(s) which became more important at higher [HFA]/[C3H8]. An estimate of the rate constant for the addition of H to HFA obtained at low [HFA]/[C3H8] yielded k9 = 8.5 × 105 l mol−1 s−1. Trifluoroacetaldehyde was identified with some reliability but many of the other heavier products formed in the H2 + HFA reaction could not be identified. Quenching cross-sections were determined for C2H4, C3H8, C4H10, and HFA relative to that for N2O.

scholarly journals Data-driven internal multiple elimination and its consequences for imaging: A comparison of strategies

Geophysics ◽  
2019 ◽  
Vol 84 (5) ◽  
pp. S365-S372 ◽  
Author(s):  
Lele Zhang ◽  
Jan Thorbecke ◽  
Kees Wapenaar ◽  
Evert Slob
Keyword(s):  
Inverse Scattering ◽  
Computational Cost ◽  
Multiple Reflection ◽  
Data Driven ◽  
Transmission Losses ◽  
Multiple Reflections ◽  
Data Set ◽  
Numerical Examples ◽  
Inverse Scattering Series ◽  
Multiple Elimination

We have compared three data-driven internal multiple reflection elimination schemes derived from the Marchenko equations and inverse scattering series (ISS). The two schemes derived from Marchenko equations are similar but use different truncation operators. The first scheme creates a new data set without internal multiple reflections. The second scheme does the same and compensates for transmission losses in the primary reflections. The scheme derived from ISS is equal to the result after the first iteration of the first Marchenko-based scheme. It can attenuate internal multiple reflections with residuals. We evaluate the success of these schemes with 2D numerical examples. It is shown that Marchenko-based data-driven schemes are relatively more robust for internal multiple reflection elimination at a higher computational cost.

scholarly journals Diffusion and chemical reaction velocity as joint factors in determining the rate of uptake of oxygen and carbon monoxide by the red blood corpuscle

1932 ◽  
Vol 111 (769) ◽  
pp. 1-36 ◽  
Keyword(s):  
Carbon Monoxide ◽  
Cross Sections ◽  
The Other ◽  
Blood Corpuscle ◽  
Reaction Velocity ◽  
Two Fluids ◽  
Mixing Chamber ◽  
Haemoglobin Solution ◽  
Moving Fluid

In a paper on this subject published four years age, Hartridge and Roughton (1927) described some preliminary experiments upon the rate of uptake of oxygen and carbon monoxide by the red blood corpuscle, the observations being made by means of their reaction velocity technique (Hartridge and Roughton, 1922–1927). The general principles of the method were as follows. Through one lead of the apparatus a suspension of reduced corpuscles in saline was forces into the mixing chamber, whilst through the other lead was forced a solution of oxygen (or carbon monoxide) in saline. The two fluids mixed in the mixing chamber within 0·001 second or less and then travelled down the observation tube. Determination of the percentage of oxyhæmoglobin (or carboxyhæmoglobin) in the moving fluid at various cross sections of the observation tube was made by means of the reversion spectroscope, these measurements, together with a knowledge of the rate of flow of the fluid down the observation tube, giving the necessary data for plotting the rate of uptake of O 2 or CO by the corpuscles against time. The most interesting feature of the results was the much slower uptake of O 2 by hæmoglobin in the intact corpuscle as compared with the of O 2 by hæmoglobin in laked solution as previously recorded by Hartridge and Roughton (1925). In the corpuscle experiments the time scale had to be expressed in hundredths of a second instead of in thousandths of a second as in the hæmoglobin solution experiments ( vide fig. 2 of Hartridge and Roghton, 1927). Confirmatory results by somewhat different technique have been obtained lately by Dirken and Mook (1931). These will be referred to again later.

Multiple Reflection Effect on Spin-Transfer Torque Dynamics in Spin Valves with a Single or Dual Polarizer

SPIN ◽  
2015 ◽  
Vol 05 (01) ◽  
pp. 1550003 ◽  
Author(s):  
Weiwei Zhu ◽  
Zongzhi Zhang ◽  
Jianwei Zhang ◽  
Yaowen Liu
Keyword(s):  
Spin Valve ◽  
Spin Transfer Torque ◽  
Multiple Reflection ◽  
Spin Transfer ◽  
Reflection Effect ◽  
Multiple Reflections ◽  
Applied Current ◽  
Negative Current ◽  
Ferromagnetic Layers ◽  
Scattering Matrix Method

In this paper, spin-dependent multiple reflection effect on spin-transfer torque (STT) has been theoretically and numerically studied in a spin valve nanopillar with a single or dual spin-polarizer. By using a scattering matrix method, we formulate an analytical expression of STT that contains the multiple interfacial reflection effect. It is found that the multiple reflections could enhance the STT efficiency and reduce the critical switching current. The STT efficiency depends on the spin polarization of both the free layer and polarizer. In the nanopillars with a dual spin polarizer, the multiple reflections would cause an asymmetric frequency dependence on the applied current, albeit exactly the same parameters are used in all three ferromagnetic layers, indicating that the frequency in the negative current varies much faster than that in the positive case.

Fluorine binding with dentin adjacent to fluoride-containing luting materials

2017 ◽  
Vol 27 (01n02) ◽  
pp. 1-9 ◽  
Author(s):  
K. Okuyama ◽  
Y. Tamaki ◽  
H. Yamamoto ◽  
K. Yagi ◽  
M. Hayashi ◽  
...  
Keyword(s):  
Cross Sections ◽  
Calcium Concentration ◽  
Acrylic Resin ◽  
Caries Prevention ◽  
The Other ◽  
Fluoride Release ◽  
Tooth Root ◽  
Tooth Structure ◽  
Dentin Surface ◽  
Acid Solubility

Tooth-bound (KOH-insoluble) fluoride contributes to caries prevention because of its low acid solubility and long retention within tooth structure. The purpose of this study was to evaluate tooth-bound fluoride in dentin, taken up from fluoride-containing luting materials, using an in-air [Formula: see text]PIXE/PIGE system. The dentin surface of tooth root cross-sections and an acrylic resin were cemented with four different fluoride-containing luting materials. Specimens were stored in a remineralizing solution for 4 or 8 weeks and then sectioned into two slices. Two adjacent slices were used for measurement of fluorine and calcium concentration using in-air [Formula: see text]PIXE/PIGE. For analysis of the KOH-insoluble fluoride ((KOH(+)), one slice was immersed in 1 mol/L KOH solution for 24 h. The other slice was not treated with KOH in order to analyze KOH-soluble and -insoluble fluoride (whole fluoride, KOH(−)). KOH(+) levels were lower than KOH(−) levels for all materials at both duration periods. Higher concentration of fluorine was detected at deeper areas in the 8-week groups than in the 4-week groups for all materials. The material, which has the largest fluoride release, shows the lowest ratio of KOH(+) to KOH(−). PIXE/PIGE analysis confirmed the presence of tooth-bound fluoride in dentin adjacent to fluoride-containing luting materials.

Microbicidal effect of reflected UV radiation in devices for water disinfection

1996 ◽  
Vol 34 (7-8) ◽  
pp. 173-177 ◽  
Author(s):  
R. Sommer ◽  
A. Cabaj ◽  
T. Haider
Keyword(s):  
Stainless Steel ◽  
Uv Radiation ◽  
Multiple Reflection ◽  
Water Disinfection ◽  
The Other ◽  
Uv Disinfection ◽  
Operating Life ◽  
Inner Surface ◽  
Relative Extent ◽  
Irradiation Chamber

A standardised biodosimetric method was used to quantify the influence of reflection on the reduction equivalent UV doses (RED) in two commercially available water disinfection systems. One device, possessing a reflector made of aluminium, showed a decrease of RED of about 40% after removing the reflector. In the other plant, made of stainless steel, the inner surface of the irradiation chamber served as a reflector by itself. After eliminating the reflectance by black lacquering the inner surface of the irradiation chamber a distinctive decrease of RED was measured. This effect depended on the transmittance of the water (253.7 nm). With increasing water transmittance an increasing relative loss of RED was observed. The results showed that the relative extent of the RED caused by reflection may even exceed the reflectance of the material due to multiple reflection, especially in water with high transmittance. However, in UV disinfection plants with inner surfaces made of reflecting material the reflectance may decrease during the operating life. Therefore, measuring the extent of reflection influencing the RED by using a suitable biodosimetric method is essential in UV devices for water disinfection.

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