Method For Determination Of Depth Research Articles

Modifying Bitumen with Recycled PET Plastics to Enhance Its Water Resistance and Strength Characteristics

This study investigates the modification of bituminous mixtures by varying percentages of PET particles (1%, 3%, 5%, 8%, 10%, and 12% PET). The following methods were employed to analyze the samples: the ring-and-ball softening point determination method (ASTM D36/D36M-14), the Fraass breaking point determination method (EN 12593: 2015), the elongation determination method (EN 13589: 2014), and the needle penetration depth determination method (EN 1426: 2015). Optimal bitumen/PET ratios were identified to obtain modified bituminous mixtures (MBMs) with enhanced operational characteristics (5% and 8% PET). The physical and mechanical properties of the investigated bitumen samples and PET were determined. A comparative analysis of the modified bituminous mixture samples based on their physical and mechanical properties was conducted. Microstructures of the surface of modified bituminous mixture samples with varying modifier contents were obtained. An X-ray structural analysis was performed on the samples of modified bituminous mixtures with varying PET contents. The dependencies of the moisture absorption rate on time were determined for the samples of modified bituminous mixtures with different modifier contents. The values of the stress intensity factor were determined based on the number of loading cycles in fatigue tests using three-point bending for the samples of modified bituminous mixtures with varying modifier contents.

Effective Penetration Depths Investigation on Synchrotron X-Ray Topographic Images of Basal Plane Dislocations in 4H-SiC Crystals through Ray-Tracing Simulation

The demand for power electronic devices fabricated from silicon carbide (SiC) has increased rapidly in recent years for a diverse range of existing and emerging applications. The development of device technology highly depends on the quality of substrate and epitaxial material and the number of deleterious defects within, as those are critical factors that impact the device performance and long-term reliability [1, 2]. Therefore, understanding the nature of defects is of great importance for preventing the degradation or premature breakdown of devices. Synchrotron X-ray topography (XRT) is a dominant analytical method for the imaging and characterization of crystallographic defects. For 4° off-axis (0001) 4H-SiC wafers, the grazing-incidence geometry topographic technique is commonly employed to focus on the defect investigation near surface region. In this geometry, a small incidence angles (~1-2°) is used for allowing X-ray to only penetrate the sample with a shallow depth below the surface, therefore, it is essential to establish a procedure to define the effective penetration depth for detailed analysis of dislocation structures and density calculations. In earlier studies, Dudley in 1989 concluded that the observed penetration depths are limited by photoelectric absorption rather than extinction [3]. Ishiji in 2017 estimated the penetration depth based on the photoelectric absorption experienced by the diffracted X-rays [4]. However, only basal plane dislocations (BPDs) with screw segments parallel to the off-cut [11-20]-direction were evaluated in that study, which is insufficient for evaluating other types of BPDs. Therefore, a universal method to determine the effective penetration depth for all dislocation types would be of more practical importance.In this study, a procedure to define this effective penetration depth is demonstrated by investigating physical vapor transport (PVT) grown 4° off-axis 4H-SiC crystals through preforming systematic analysis of topographic and ray-tracing simulated contrast of BPDs with different Burgers vector and line direction combinations. The topographic images are recorded through synchrotron monochromatic beam in grazing incidence geometry. The simulation model is based on the principle of orientation contrast mechanism [5, 6] and developed by considering both the effects of surface relaxation [7] and X-ray absorption [8, 9] for evaluating the contributed factors of dislocation contrast formation. Analysis of the results indicates the observable dislocation contrast depends on the effective misorientation associated with the dislocation modulated by the photoelectric absorption effect. The dislocations with larger effective misorientation are associated with longer projected lengths and corresponding deeper effective penetration depths. A more simplified factor based on an approximate expression for the misorientation is also introduced in this study as an alternative to the full ray-tracing simulation approach. The effective penetration depth determination method presented in this study enables three-dimensional dislocation configuration analysis and accurate density calculations.Reference: Das, H., et al., Materials Science Forum, 2019. 963: p. 284-287.Kimoto, T., et al. 2017 IEEE International Reliability Physics Symposium (IRPS). 2017.Dudley, M., J. Wu, and G.D. Yao, Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 1989. 40-41: p. 388-392.Ishiji, K., et al., Japanese Journal of Applied Physics, 2017. 56(10): p. 106601.Dudley, M., X.R. Huang, and W. Huang, Journal of Physics D: Applied Physics, 1999. 32(10A): p. A139-A144.Huang, X.R., et al., Journal of Applied Crystallography, 1999. 32(3): p. 516-524.Peng, H., et al., Journal of Applied Crystallography, 2021. 54(2): p. 439-443.Fujie, F., et al., Acta Materialia, 2021. 208: p. 116746.Ailihumaer, T., et al., Materials Science and Engineering: B, 2021. 271: p. 115281. Figure 1

Delineation of structural lineaments of Southeast Nigeria using high resolution aeromagnetic data

Abstract Structural lineaments of Southeast Nigeria were delineated using high-resolution aeromagnetic data. Advanced methods such as enhanced horizontal gradient amplitude (EHGA) involving a 3D model and tilt depth method (TDM) were used in this study. The simulated magnetic model involving the EHGA detector positioned peaks over source borders and created sharp and clear edges for magnetic sources. The TDM is a cutting-edge depth determination method revealing the depth of the contacts and thickness of sedimentary bodies that vary from ∼500 to ∼2,500 m and ∼3,000 to ∼5,000 m, respectively. Lineaments of the study area were extracted from the EHGA map. The structural map showed the dominance of short-ranged (∼0.29 to ∼1.48 km) linear magnetic anomalies. In addition, regional geologic structures (∼2.8 to ∼24.5 km) occur at the western flank of the study area. In general, these structures trend in the NE–SW, NNE–SSW, N–S, E–W, and NW–SE directions. They are indicators of subsurface faults, contacts, and tectonic structures of the thermo-tectonic events associated with Santonian Abakaliki Anticlinorium, Tertiary-Recent Ikom-Mamfe Rift, and structural deformations of the basement rocks associated with the Oban Massif.

Accurate depth determination of defects in composite materials using pulsed thermography

The determination of defect depth is one of the important advantages of pulsed thermography. The existing methods for depth estimation in pulsed thermography are generally established based on the one-dimension heat conduction along the thickness of the sample. However, most of the methods neglect the effects of defect size and sample thickness, which induces additional systematic errors in depth estimation. In this study, simulations are conducted to demonstrate that the accuracy of depth determination of defects is greatly influenced by the defect size and sample thickness in some simulations. By establishing the relationship between the characteristic time and these factors, an accurate depth determination method based on the peak slope time is proposed. The proposed method has been applied to characterize the defect depths of a composite panel with flat-bottomed holes. The experimental results show that the use of the proposed method is able to identify the depths of defects with high accuracy.

Calibrated bubble depth determination using a single camera

Current non-intrusive bubble parameter measurement techniques fail to consider bubble depth when extracting parameters from 2-D images, resulting in inaccurate measurements. A bubble depth determination method is therefore proposed here that uses a correlation between depth and image focus to estimate depth using the edge intensity gradient (“blur”) with simultaneous depth calibration. Images of bubbles at various depths in two-phase and three-phase systems were analysed to correlate bubble depth and blur. To increase the reliability of the methodology across various fluids and conditions, an in-situ calibration method is demonstrated. Bubble depth can be correlated from blur with a fair degree of reliability and the calibration procedure was effective in validating the bubble depth model, even across differing fluid opacity, bubble concentration, and fluid conditions. This article outlines a versatile and robust system that requires a single camera and which enables per image calibration to compensate for experimental configurational changes, making the technique suitable for variable applications.

Study on the method for determination of the maximum depth of loess collapsible under overburden pressure

Determination of the maximum depth of loess collapsible under overburden pressure is an important issue in the mechanics of loess and engineering research. The maximum depth of loess collapsible under overburden pressure is determined by testing the coefficient of collapsibility under overburden pressure, which differs from a trial pit field immersion test. Such a field test, however, is costly and therefore inadvisable for wide application in engineering practice. To identify a new laboratory test method for determination of the depth of loess collapsible under overburden pressure, loess samples were collected from the north suburb of Xi’an City, Shaanxi Province, China. Compression tests and tests of the coefficient of collapsibility (also referred to as hydrocollapse) under overburden pressure (also referred to as saturated self-weight stress) were conducted on these samples, and then their pore volumes and pore ratios were measured. From an in-depth analysis of the test results, a method was proposed for determination of the depth of loess collapsible under overburden pressure, namely the depth can be determined based on the variation of pore volumes or pore ratios with depth. The results from this paper for determination of the depth of loess collapsible under overburden pressure, which were verified by examples, are highly consistent with those from field tests. The method proposed in this paper is not only feasible but also less expensive and requires less time for test completion compared with field tests. Therefore, the method should be further investigated and considered for wider application.

English

This study focuses on the quantitative interpretation of aeromagnetic data to estimate the thickness of sediments over part of Bida Basin so as to identify possible areas of hydrocarbon potential. The study area covers an area of 24,200 km2 located between latitude 8° 30ežŒN and 9° 30ežŒN and longitudes 5° 00ežŒE and 7° 00ežŒE. Aeromagnetic data in grid format containing eight sheets were analysed and interpreted. Polynomial fitting was used in regional/residual separation and this result to the residual field data that corresponds to the target source for further processing. Three depth estimating methods were employed in this study; Euler deconvolution, source parameter imaging and spectral depth analysis. Euler depth determination method reveals a maximum depth of 3.56 km around Mokwa and Batati areas. Shallow sources also exist around Pategi, Paiko, Izom and Lapai areas with an average depth ranging from 107.74 m to about 514.82 m. Source parameter imaging shows a deeper sedimentary thickness of 4.2 km in the same area with Euler deconvolution. Spectral depth analysis also showed a maximum sedimentary thickness of 3.50 km. It was found in the study that the maximum depths obtained might probably be sufficient enough for hydrocarbon maturation and gas accumulation. Further research using seismic reflection might be carried out in the areas where maximum depth was obtained. Key words: Aeromagnetic data, polynomial fitting, spectral analysis, euler deconvolution source parameter imaging.

A simple method for depth determination from self-potential anomalies due to two superimposed structures

In this paper, we develop a method to determine the depth to two superimposed sources from a self-potential anomaly profile. The method is based on finding a relationship between the depths to the two superimposed structures from a combination of observations at symmetric points with respect to the coordinate of the sources’ centre. Formulae have been derived for two classes of geometric sources: spheres and cylinders. Equations are also formulated to estimate the other model parameters, including the polarisation angle and electric dipole moment of both structures. The proposed method is tested both on synthetic data with and without random noise, as well as real self-potential data from a set of field data collected in Turkey. In all cases, the model parameters obtained are in good agreement with the actual ones.

Matched filtering method for separating magnetic anomaly using fractal model

Fractal/scaling distribution of magnetization in the crust has found with growing body of evidences from spectral analysis of borehole susceptibility logs and magnetic field data, and fractal properties of magnetic sources have already been considered in processing magnetic data such as the Spector and Grant method for depth determination. In this study, the fractal-based matched filtering method is presented for separating magnetic anomalies caused by fractal sources. We argue the benefits of considering fractal natures of source distribution for data processing in magnetic exploration: the first is that the depth determination can be improved by using multiscaling model to interpret the magnetic data power spectrum; the second is that the matched filtering can be reconstructed by employing the difference in scaling exponent together with the corrected depth and amplitude estimates. In the application of synthetic data obtained from fractal modeling and real aeromagnetic data from the Qikou district of China, the proposed fractal-based matched filtering method obtains more reliable depth estimations as well as improved separation between local anomalies (caused by volcanic rocks) and regional field (crystalline basement) in comparison with the conventional matched filtering method.

Estimating depth to the bottom of magnetic sources at Wikki Warm Spring region, northeastern Nigeria, using fractal distribution of sources approach

Abstract: The Wikki Warm Spring (WWS) is located on the Kerri-Kerri formation of tertiary age. This forms part of the Benue Basin, which links up with the Chad Basin in the north and extends southwest to the Anambra Basin in Nigeria. The stratigraphy of the WWS region consists of alluvium, the Kerri-Kerri formation, the Gombe formation, the Pindiga formation, the Yolde formation, the Bima formation, and basement rocks as the oldest. We estimate the depth to the bottom of magnetic sources (DBMS) in the WWS region using the fractal sources distribution approach on aeromagnetic data to identify the geothermal system of the WWS region. The adopted computational method is based on statistical methods of depth determination from the radial power spectrum assuming a fractal distribution of magnetic sources. The average estimated DBMS at the WWS source location is 10.72 ± 0.54 km. The obtained results imply an average thermal gradient of 54.11 °C km-1 and heat flow value of 135.28 mW/m2. Generally, shallow DBMS values are obtained in the northeastern region of the WWS area and these increase towards the southwestern region when regional variation patterns of estimated depths are considered. The generally shallow DBMS obtained in the study area is attributed to magmatic intrusion or diapirism in the subsurface and emphasizes the effects of large-scale tectonic events, particularly the basin-initiating event, as major influences on the thermal history. Results will contribute to decisions on where to drill boreholes for further geothermal energy exploration in the region.

SU‐FF‐I‐107: Study of An Adaptive Planning in the Proton Therapy

We evaluated the feasibility of automated depth determination‐based adaptive proton therapy to minimize the effect of inter‐fractional movements of the prostate. Based on the center of mass method, using three fiducial gold markers in the prostate target volume, we determined the differences in prostate target location between the planning and treatment stages. Thirty‐eight images from 10 patients were used to assess the automated depth determination method, which was also compared with manually determined depth values. The mean differences in prostate target location for the left to right (LR) and superior to inferior (SI) directions were 0.9 mm and 2.3 mm, respectively, while the maximum discrepancies in location in individual patients were 3.3 mm and 7.2 mm, respectively. In the bilateral beam configuration, the difference in the LR direction represents the target depth changes, which was found to range from 0.7 mm to 3.3 mm in our study. We found that 42.1%, 26.3% and 2.6% of thirty‐eight inspections showed greater than 1 mm, 2 mm and 3 mm depth differences, respectively, between the planning and treatment stages. Adaptive planning based on automated depth determination may be a solution for inter‐fractional movements of the prostate in proton therapy since small depth changes of the target can significantly reduce target dose during proton treatment of prostate cancer patients.

Subsurface structural mapping of the area lying between Gabal Elgalala Elqibliya and Elgalala Elbahariya, Northern Eastern Desert, Egypt

The area lying between Gabal Elgalala Elqibliya and Elgalala Elbahariya is located in the Northern Eastern Desert of Egypt, between 28° 49' N and 29° 10' N and 31° 50' E and 32° 30' E. The exposed rock units in the study area are represented by various lithologic associations ranging in age from Late Paleozoic to Quaternary. I applied gradient interpretation techniques (analytic signal and Euler deconvolution) as well as magnetic modelling to the aeromagnetic data, to delineate the subsurface structural features and estimate depths to basement. The results of all methods of depth determination suggest a fault-controlled region, especially in its eastern part. Moreover, moving from its western side towards its eastern side, the study area could be represented by a series of horsts (domes or anticlines) and grabens (troughs, basins or synclines) ranging in depth between 0.1 and 4.0 km. The study area is intruded by two nearly parallel systems of more basic and more recent dykes than the surrounding rocks, at depths varying from 0.2 km and 2.0 km.

Membrane localization and dynamics of Nile Red: Effect of cholesterol

The organization and dynamics of the hydrophobic fluorescent probe Nile Red incorporated in DOPC vesicles containing varying amounts of cholesterol has been monitored utilizing fluorescence-based approaches which include the red edge excitation shift (REES) approach and the parallax method for depth determination. Our results show that the fluorescence emission maximum, intensity, polarization, and lifetime of Nile Red vary with the cholesterol content of the membrane. Interestingly, Nile Red exhibits significant REES independent of the presence of cholesterol. This indicates that Nile Red is localized in a motionally restricted environment in the membrane. This is supported by analysis of membrane penetration depth of Nile Red using the parallax method which points out to a membrane interfacial localization of Nile Red. These results could be useful in analyzing membrane organization and heterogeneity in natural membranes using Nile Red.

Determination of target depth in a turbid medium with polarization-dependent transmitted signals.

We demonstrate a novel method for target depth determination in a turbid medium with experiments and Monte Carlo simulations. This method relies on the strong dependence of transmitted co-polarized intensity on target depth. Such a dependence originates from the inclusion of certain diffuse photons in the co-polarized intensity. A target of stronger scattering located closer to the transmitter results in stronger photon divergence and hence weaker co-polarized intensity at the receiver of a finite aperture. On the other hand, the degree of polarization (DOP) carries only information about ballistic and snake photons. It is weakly dependent on the target depth. The DOP data can be used as a reference of absolute scattering strength in the turbid system. Our experimental and Monte Carlo simulation results show the feasibility of the proposed target depth determination method. Meanwhile, it is shown that an appropriate time-gating process could help in improving the accuracy of target depth. In addition, the results show that the proposed method has quite large applicable ranges of scattering coefficient and absorption coefficient.

Inherent power‐law behavior of magnetic field power spectra from a Spector and Grant ensemble

The Spector and Grant method, which has been in use for 25 years, relates average depths to source to rate of decay of the magnetic power spectra. This method, which assumes a uniform distribution of parameters for an ensemble of magnetized blocks, leads to a depth‐dependent exponential rate of decay. We show that also inherent in this model is a power‐law rate of decay that is independent of depth. For most cases, except for extreme depths and small block sizes, the observed power spectrum should be corrected for a power law decay rate of β∼3. If the depth distribution of the magnetic blocks is Gaussian, then the observed power spectrum should be corrected for both a depth independent power law and exponential decay. This power‐law decay is very similar to the scaling behavior, supposed as a fractal character, of observed magnetic fields in North America. As a general rule, when β∼3, further information is needed to discriminate between a fractal or Spector and Grant model. However, it is becoming quite clear that magnetic power spectra should be corrected for a power law decay before applying the Spector and Grant method for depth determination.

On: “Exploration of a Lignite‐Bearing Basin in Northern Ireland Using Ground and Magnetic VLF-EM Methods,” R. J. McCaffrey, John McElroy, and Graham Leslie (March‐April 1995 GEOPHYSICS, p. 408–412)

This paper presents an analysis of ground magnetic and VLF-EM data over a basin of several hundred acres which is an appendage to the larger Lough Neagh autogeosynclinal basin in northeastern Ireland. There is little to do with lignite and the VLM-EM of the title. There is quite a bit to do with the magnetic sector which is, however, not analyzed by time‐proven methods of depth determination but rather by running a synthetic, one dimensional first derivative over the traverses given the name MAGGRO.

Application of aeromagnetic data to mineral potential evaluation in Minnesota

Aeromagnetic, ground magnetic, and gravity data, together with all available drillhole data and physical property measurements, were used to map the Precambrian geology of an area in Minnesota that is virtually devoid of outcrop. The work was done for purposes of land use planning and to encourage minerals exploration and mostly consisted of the analysis of profiles of aeromagnetic data to map magnetic/lithologic contacts, to infer structure, and to determine thickness of overburden cover. Two greenstone belts were resolved. They comprise higher density rocks separated by nonmagnetic metasedimentary intervals. The belts are deformed into synclinal structures that, according to modeling, range from 1 km to as much as 5 km in depth. Lithologic predictions were confirmed in five out of six holes drilled on completion of the magnetic interpretation. In over 40% of the area, Precambrian rocks are apparently mantled by less than 50 m of overburden, and in 50% of the area there is between 50 and 100 m of overburden cover. In the remaining 10%, the magnetic basement is overlain by a thick blanket of nonmagnetic Precambrian sedimentary rocks, over 200 m thick. Basement depth determinations were subsequently tested at six holes. Depth determinations at all drill sites were found to lie within the 20% error expectation of the method of depth determination. Thirty‐seven sites were resolved from the aeromagnetic data as targets for basemetal sulfide (copper, zinc) as well as precious metal (gold) mineralization. Thirteen magnetic anomalies were identified as possible kimberlite pipes.

Earthquake source parameters and stress distribution in the Adak Island region of the central Aleutian Islands, Alaska

Source parameters have been systematically determined for all earthquakes with Mw≥5 that occurred between 172°W and 179°W longitude in the Adak Island region of the central Aleutian Islands during 1977‐March 1987. We relocate the events using a plate velocity model developed for the region and use two alternative methods of depth determination. The first method uses arrival times of direct and prominent reflected phases, primarily pwP. The second method uses broadband P wave displacement seismograms in an inversion for source depth. The analysis of these events provides a well‐constrained data set for the study of stress release along an active subduction zone. Three earthquakes, which occurred seaward of the trench axis, are located just below the crust‐mantle interface and show extension nearly perpendicular to the trench axis. Seven events occurred in the Wadati‐Benioff zone. Sixty‐four events are located in the main thrust zone, and, except for five unusual events, are characterized by thrust mechanisms with one nodal plane dipping north at a shallow angle. In cross section the thrust zone appears as a thin (10–15 km thickness) interplate region which extends from 15 to 50 km depth. A 10°–15° average discrepancy between observed slip vector azimuths and the predicted relative motion direction between the Pacific and North American plates exists for these events. The observed slip vectors are oriented more normal to the trench than is predicted by plate motions. Five earthquakes, which occurred as aftershocks to the May 7, 1986, earthquake (Mw = 8.0), in the crust of the overriding plate have strike‐slip mechanisms consistent with right‐lateral motion on arc‐parallel fault planes. Observations of slip vectors along the whole Aleutian arc show a similar trend to that observed in the Adak Island region. The largest differences (∼30°) between observed and predicted slip azimuths occur around 175°E. We propose a model of plate interaction in which a portion of the along‐arc motion occurs along a weak strike‐slip shear zone in the upper plate, near the volcanic line. The slip azimuths in the main thrust zone fit this model well, if the amount of transcurrent slip occurring in the upper plate is ∼60% of the arc‐parallel relative plate motion. A consequence of the model is along‐arc extension of the overriding plate between the accretionary wedge and the volcanic line, especially in the western part of the Aleutian arc. Calculations based on a tectonic model by Geist et al. (1988) for the formation of arc summit basins through block rotation and translation, suggest that along‐arc extension has been significant since late Miocene or early Pliocene.

A Simple Method For Determination of Depth of Investigation Characteristics in Resistivity Prospecting

Abstract For determination of depth of investigation characteristics in direct-current resistivity methods, individual contribution from an infinite horizontal sheet of infinitesimal thickness within a homogeneous half-space has been obtained through the solution of boundary value problems. In this study, no assumption is made of electrostatic equivalence or dipole polarization, which has been utilized by earlier workers.

Monocular depth perception from optical flow by space time signal processing

A theory of monocular depth determination is presented. The effect of finite temporal resolution is incorporated by generalizing the Marr-Hildreth edge detected operator —∇ 2 G(r) where ∇ 2 is the Laplacian and G(r) is a two dimensional Gaussian. The constraint that the edge detection operator in space-time should produce zero-crossings at the same place in different channels, i. e. at different resolutions of the Gaussian, led to the conclusion that the Marr-Hildreth operator should be replaced by -□ 2 G(r, t) where □ 2 is the d’Alembertian ∇ 2 -(1/ u 2 ) (∂ 2 /∂ t 2 ) and G(r, t) is a Gaussian in space-time. To ensure that the locations of the zerocrossings are independent o the channel width, G(r, t) has to be isotropic in the sense that the velocity u appearing in the defintion of the d’Alembertian must also be used to relate the scales of length and time in G . However, the new operatior -□ 2 G(r, t) produces two types of zero-crossing for each isolated edge feature in the image I(r, t) . One of these, termed the 'static edge’, corresponds to the position of the image edge at time t as defined by ∇ 2 I(r, t) = 0; the other, called a ‘depth zero’, depends only on the relative motion of the observer and object and is usually found only in the periphery of the field of view. When an edge feature is itself in the periphery of the visual field and these zeros coincide, there is an additional cross-over effect. It is shown how these zero-crossings may be used to infer the depth of an object when the observer and object are in relative motion. If an edge feature is near the centre of the image (i. e. near the focus of expansion), the spatial and temporal slopes of the zeros crossing at the static edge may be used to infer the depth, but, if the edge feature is in the periphery of the image, the cross-over effect enables the depth to be obtained immediately. While the former utilizes sharp spatial and temporal resolution to give detailed three-dimensional information, the cross-over effect relies on longer integration times to give a direct measure of the time-to-contact. We propose that both mechanisms could be used to extract depth information in computer vision systems and speculate on how our theory could be used to model depth perception in early visual processing in humans where there is evidence of both monocular perception of the environment in depth and of looming detection in the periphery of the field of view. In addition it is shown how a number of previous models are included in our theory, in particular the directional sensor proposed by Marr & Ullman and a method of depth determination proposed by Prazdny.