Exact Depth Research Articles

Imaging Top of Volcanic Mounds Using Seismic Time- and Depth-Domain Data Processing

A seismic survey identified a basalt flow that could consist of cap rock of CO2 storage beneath saline aquifer sediment in the Southern Continental Shelf of Korea. To determine the precise depth of the basalt flow, specific depth-domain data processing of migration velocity analysis (MVA) was applied to the seismic survey data. The accurate depth measurement of a target structure provides crucial information when storing and stabilizing injected CO2 beneath basalt cap rock. Strong reflections of seismic amplitude at the volcanic mounds were adjusted from the time domain to the exact depth domain by the iterated velocity using MVA. The confidence of the updated velocity was verified by the horizontal alignment of seismic events sorted according to their common reflection point (CRP). The depth difference in volcanic mounds before and after MVA application ranged from 32.5 to 60 m along the vertical axis, showing the eruption shape on the strong-amplitude contour map in detail. The eruption shape of the top of volcanic mounds was verified with spatial continuity in 3D geological interpretation. The presented results provide suitable information that can be used to locate drilling sites and to prepare CO2 injection. The geological model obtained from both time- and depth-domain processing can significantly influence the calculation of the storage volume and can be useful for history matching studies.

Precision sowing of vegetable seeds using electrically operated distribution devices

The high efficiency of vegetable crops is influenced, in addition to soil preparation works, weed, diseases and pests control, irrigation, etc. by precision sowing, which involves placing a certain number of seeds at an exact depth and distance. Thus, cost savings, a high reliability of production and especially a greater uniformity of crops are achieved, most often uniform and quality productions being obtained. For vegetable species in the case of which harvesting is practiced only once, uniformity of seed distribution is particularly important. In most cases, vegetable seeds have small size, irregular shape and small mass. These characteristics make the development of precision seeders for this type of seed quite difficult. Precision sowing of vegetable seeds ensures a correct sowing rate, which implies an optimal space for plant growth and development, thus improving crop yields. The paper presents a summary of the current state of precision seeders equipped with electrically operated distributors for vegetable seeds, as well as the preliminary results of research conducted by authors in this field.

Subsidence and maturation evolution of a new lower-slope minibasin, Xingning Sag, northern South China Sea

Study of Subsidence and maturation evolution of a continental slope basin without a drilled well is an important problem in the early stage of deep-water exploration. Lack of some parameters, such as stratigraphic-age, porosity-depth relationship, exact paleo-water depth and heat flow value are common problems in the study of subsidence and maturity history. Using 46 long 2D seismic lines and paleo-water depth data from paleontological data of a well on the slope toe, the present study combines backstripping with thermal modeling to reconstruct the subsidence and maturation evolution of a lower-slope minibasin, Xingning Sag (XS), on the southeast Pearl River Mouth Basin (PRMB) of the South China Sea (SCS), now a new prospecting area. Stratigraphic-ages, porosity-depth relationship, lithology of XS were estimated using data from an adjacent basin. Paleo-water depths were obtained by clinoform geometry using seismic facies and paleontological method. With these parameters, the subsidence curves were created by backstripping. Crustal stretching factors (β) were obtained by best fit of tectonic subsidence curve and thermal modeling. With these stretching factors, the theoretical subsidence and heat flow values were obtained at the same time. Based on the heat flow value and the backstripping parameters, the maturation history of this basin was simulated. The result shows XS evolved through three cycles of subsidence during 46–23.03 Ma, 23.03–13.82 Ma and 13.82–0 Ma, respectively. Each cycle shows a rifting phase of relatively rapid tectonic subsidence followed a cooling phase of slow subsidence. Potential Eocene lacustrine source rocks are distributed primarily in the central depression area (Xingning main sub-sag), and would have entered the main oil-generation window and main gas generation during early- and mid-Miocene respectively.

Seasonal Comparison of Potential Groundwater Aquifer in Ijebu-Ife, South-West, Nigeria, using Dipole-Dipole Array and Electromagnetic Methods

Seasonal comparison of potential groundwater aquifer unit using integrated geophysical methods at Ijebu-Ife, Ogun State, South-west, Nigeria was investigated. The fieldwork employed two seasons (dry and wet seasons). The electromagnetic method employed the Very low frequency and its data was acquired during the dry and wet seasons along with five profiles of Dipole-dipole array covering 500 m length using ABEM WADI VLF equipment and was processed using the KAROUS-HJELT software. The 2 – D Dipole-dipole data were also acquired along with five (5) traverse for both seasons making a total number of ten (10) and was processed with DIPROFWIN software. The results of the Integrated Dipole-Dipole and VLF-EM data identified three geoelectric layers based on its electrical resistivity and conductivity distribution. The study identified a clayey sand horizon which constitutes a good aquifer zone. The study reveals in, comparison, that during the dry season, all layer resistivities are high with low depth while during the wet season; all layer resistivities are low with high depth. Also, conductivity during the wet season is high at high depth than conductivity which is low at low depth during the dry season. The study concluded that, in water exploration, drilling of water should be done during the dry season in other to locate the exact depth of water.
 

Ultrasound Guided Laparoscopic Radiofrequency Ablation for Very Large Multi-Fibroid Uterus

Study Objective This video describes the technique and advantages of laparoscopic radiofrequency ablation with ultrasound guidance for the treatment of very large multi-fibroid uteri. Design N/A Setting Large tertiary care hospital. Patients or Participants 45-year-old gravida 2 para 0 female with menorrhagia, dysmenorrhea, and bulk symptoms secondary to a very large multi-fibroid uterus. She desired a minimally invasive and uterine conserving method to treat her symptoms. Interventions We performed laparoscopic radiofrequency ablation under ultrasound guidance for the patients’ multiple fibroids. The uterus was mapped ultrasonographically using the laparoscopic ultrasound transducer. Next, under laparoscopic visualization, the needle handpiece was inserted into the abdomen three centimeters away from the ultrasound transducer insertion point. With careful coordination between visualization on the ultrasound and the laparoscope, the handpiece was directed into specific myomas for ablation with deployment of the needle arrays. This allowed emission of radiofrequency energy to shrink the myoma tissue. The exact depth and total ablation time is calculated for each deployment prior to initiation of the ablation. It is important to note that larger myomas may require multiple overlapping treatments due to their size and density. The procedure was performed in an outpatient setting with an estimated blood loss of less than 10 milliliters. Measurements and Main Results N/A Conclusion Laparoscopic radiofrequency ablation for very large multi-fibroid uteri can be successfully performed under ultrasound guidance as a uterine conserving method to treat symptomatic fibroids. The technique has many advantages when compared to other surgical techniques used to treat fibroids, including minimal blood loss, decreased post-operative pain, shorter recovery time, and a potentially narrower learning curve given that advanced laparoscopic suturing skills are not required.

Measuring vergence and fixation disparity in 3D space

As the eyes continuously move in 3D space, they rarely converge at the exact depth of the plane even when fixating a 2D image or computer screen. Rather, the lines of gaze measured by eye movement recordings show some misalignment so-called fixation disparity. Fixation disparity occurs in front of or behind the plane, and the eyes may also be lagged vertically. For those reasons, vision research requires mathematical tools to calculate where exactly the lines of gaze cross the stimulus plane. Seminal research on vergence eye movements targeting stimuli lying on isovergence curves has been content with simple computation of the difference between the two eye rotation angles. Recently, the need of new calculations has emerged with the increasing use of eye-trackers providing the eye coordinates on a computer screen. Previous studies have made this attempt but with restrictions. We introduce here a complete calculation of fixation disparity in 3D space allowing vision researchers to study the precision of gaze regardless of the stimulus location in 3D space and of whether the eyes lag horizontally and/or vertically.

Cannula versus needle in medical rhinoplasty: the nose knows.

The use of hyaluronic acid (HA) fillers has become a popular alternative for nose remodeling, although poor understanding of the nasal anatomy has resulted in adverse events and generated some controversy. Among them, is the question of where and when to use cannulas vs needles. Through multiple cadaver dissections, clinical experience and the review of medical literature the authors conclude the use of needle over cannula is preferred, assuring a correct injection plane lying fully against the bone or cartilage. Although blunt in nature, cannulas may lead to difficulty in determining with precision the exact depth of product placement and contribute to more dissection of adjacent structures. Thorough knowledge of the highly variable nasal anatomy, including vessel depth location is of outmost importance in avoiding adverse events. Good patient selection is critical where most noses for augmentation rhinoplasty and some reduction rhinoplasty candidates where the goal is to camouflage the dorsal hump are amenable to medical rhinoplasty, unless there is reduced skin elasticity of nasal soft tissues or distortion of anatomy from surgery or trauma. Appropriate product selection is important for effective results. The authors suggest fillers with low cohesivity and high lifting capacity. Finally, we suggest a technique referred as Rhinosculpting base in the use the use of three conceptual elements: facial analysis, light reflection, and use of HA gel as a cartilage graft, in combination with the detailed injection technique presented in this article, which ensures a safer and satisfying treatment outcome.

A new measurement of the deepest depth of the ocean

Scientists and explorers have been searching to determine the exact location and depth of the deepest part of the ocean since the HMS Challenger made the first sounding of the Mariana Trench in 1875. The consensus is that the deepest abyss in the ocean is in the Challenger Deep, a portion of the Mariana Trench with depths greater than 10 000 m. Since the HMS Challenger II returned to the Mariana Trench in 1952, 14 estimates of the deepest depth of the ocean have been made. Estimates of the location and maximum depth are as diverse as the methods used including wire soundings, explosives, single and multibeam sonars, and remotely operated and manned submersibles. During an Office of Naval Research supported expedition to the Challenger Deep in 2014, two free falling passive acoustic instruments were deployed. The implosion of one instrument was recorded by the other when both were at depths greater than 8000 m. Multiple reflections from the seafloor and sea surface of the sound generated by the implosion were used to determine the depth of the Challenger Deep. The result was the most constrained estimate of the deepest part of the ocean, 10 991 ± 6 m.

Mathematical modeling and numerical simulation for determining an optimized oil jet layout for spiral bevel gear lubrication

In aeroengine industry, the oil jet layout significantly influences lubrication of high-speed and heavy-load transmission gears, as there is only extremely limited meshing clearance for the oil stream jetting into and an inevitable blocking effect of rotating gears. A novel mathematical model for calculating the exact impingement depth of the lubrication oil jet on the spiral bevel gear surface has been established, and it contains comprehensive and detailed design parameters for the jet nozzle layout and meshing gears. Furthermore, under different jet layout parameters conditions, computational fluid dynamic numerical simulations for oil jet lubrication of an aeronautical spiral bevel gear pair were conducted and, then, the simulation results are compared with the impingement depths based on the mathematical model. The simulation results reveal that the oil volume fraction and oil pressure on the meshing area increase with the impingement depth, validating the effectiveness and reliability of the method using the impingement depth mathematical model for evaluating oil jet lubrication. Optimized oil jet layout parameters including the jet nozzle position, jet elevation angle, and jet azimuth angle have been determined and recommended, and they provide valuable theoretical design methods and technical guidance for oil jet lubrication optimization for various practical high-speed and heavy-load spiral bevel gears.

Inferring rheology and geometry of subsurface structures by adjoint-based inversion of principal stress directions

SUMMARY Imaging subsurface structures, such as salt domes, magma reservoirs or subducting plates, is a major challenge in geophysics. Seismic imaging methods are, so far, the most precise methods to open a window into the Earth. However, the methods may not yield the exact depth or size of the imaged feature and may become distorted by phenomena such as seismic anisotropy, fluid flow, or compositional variations. A useful complementary method is therefore to simulate the mechanical behaviour of rocks on large timescales, and compare model predictions with observations. Recent studies have used the (non-linear) Stokes equations and geometries from seismic studies in combination with an adjoint-based approach to invert for rheological parameters that are consistent with surface observations such as GPS velocities. Nevertheless, it would be useful to use other surface observations, such as principal stress directions, as constraints as well. Here, we derive the adjoint formulation for the case that principal stress directions are used as observables with respect to rheological parameters. Both an algebraic and a discretized derivation of the adjoint equations are described. This thus enables the usage of two data fields - surface velocities and stress directions - as a misfit for the inversion. We test the performance of the inversion for principal stress directions on simplified 3-D test cases. Finally, we demonstrate how the adjoint approach can be used to compute 3-D geodynamic sensitivity kernels, which highlight the areas in the model domain that have the largest impact on the misfit value of a particular point. This provides a simple, yet powerful, way to visualize which parts of the model domain are of key importance if changing rheological constants.

Combined electrical resistivity imaging and ground penetrating radar study for detection of buried utilities in Federal University of Agriculture, Abeokuta, Nigeria

The knowledge of the exact location and depth of buried utility such as pipes assists greatly for prevention of accidents and wastage of resources. This study addresses the application of integrated geophysical methods for detections of buried utility in student’s residential hostels, Federal University of Agriculture, Abeokuta, southwestern Nigeria. The goals of the surveys are to determine the effectiveness of the applied methods in detection of buried utilities locations and their depths as well as verification of obtained depths to the top of target by excavation method. 2D electrical resistivity imaging (ERI) using Wenner array with electrode separation ranging from 0.25 to 1.25 m and ground penetrating radar (GPR) survey using a common-offset profiling and center frequency of 400 MHz were carried out along ten traverses in the study area. The field data were processed using RES2DINV and RADAN 7 softwares for resistivity and GPR data, respectively. Inverted resistivity sections and Radar Images generated information up to a depth of 0.80 m and 3.00 m, respectively. The position, size, and depth of buried pipes cannot be determined precisely by ERT compared to GPR survey. The depths to the top of buried pipes by ERT ranges from 0.20 to 0.46 m, while the GPR measured depths ranged from 0.16 to 0.55 m from the surface. Integrated interpretation showed that GPR can effectively provide information about locations and depths to the top of buried pipes with a higher precision than ERT method. Comparisons of measured GPR depths with in-situ verification using excavation method correlate fairly well.

Uniform convergence rates for the approximated halfspace and projection depth

The computational complexity of some depths that satisfy the projection property, such as the halfspace depth or the projection depth, is known to be high, especially for data of higher dimensionality. In such scenarios, the exact depth is frequently approximated using a randomized approach: The data are projected into a finite number of directions uniformly distributed on the unit sphere, and the minimal depth of these univariate projections is used to approximate the true depth. We provide a theoretical background for this approximation procedure. Several uniform consistency results are established, and the corresponding uniform convergence rates are provided. For elliptically symmetric distributions and the halfspace depth it is shown that the obtained uniform convergence rates are sharp. In particular, guidelines for the choice of the number of random projections in order to achieve a given precision of the depths are stated.

DIGITAL VOLUME SCANNING SYSTEM FOR IMPROVING THE QUALITY OF GARDEN RETRACTION

Digital 3D scanning technology of the CAD / CAM system was used to increase the accuracy of the stump depth of the examined teeth. Collapsible plaster models were made for each clinical case and scanned in the CAD system - digital volume scanner. Using this technology on a 3D model to determine the exact depth of preparation of the stump. It was found that the study by digital volume scanning to determine and verify the depth of preparation of the examined teeth by orthopaedists, allows a more accurate and careful approach to the rationality of retraction for fixed orthopaedic structures.

A Lesion-Based Convolutional Neural Network Improves Endoscopic Detection and Depth Prediction of Early Gastric Cancer.

In early gastric cancer (EGC), tumor invasion depth is an important factor for determining the treatment method. However, as endoscopic ultrasonography has limitations when measuring the exact depth in a clinical setting as endoscopists often depend on gross findings and personal experience. The present study aimed to develop a model optimized for EGC detection and depth prediction, and we investigated factors affecting artificial intelligence (AI) diagnosis. We employed a visual geometry group(VGG)-16 model for the classification of endoscopic images as EGC (T1a or T1b) or non-EGC. To induce the model to activate EGC regions during training, we proposed a novel loss function that simultaneously measured classification and localization errors. We experimented with 11,539 endoscopic images (896 T1a-EGC, 809 T1b-EGC, and 9834 non-EGC). The areas under the curves of receiver operating characteristic curves for EGC detection and depth prediction were 0.981 and 0.851, respectively. Among the factors affecting AI prediction of tumor depth, only histologic differentiation was significantly associated, where undifferentiated-type histology exhibited a lower AI accuracy. Thus, the lesion-based model is an appropriate training method for AI in EGC. However, further improvements and validation are required, especially for undifferentiated-type histology.

The length and depth of compact Lie groups

Let G be a connected Lie group. An unrefinable chain of G is defined to be a chain of subgroups G = G_0> G_1> cdots > G_t = 1, where each G_i is a maximal connected subgroup of G_{i-1}. In this paper, we introduce the notion of the length (respectively, depth) of G, defined as the maximal (respectively, minimal) length of such a chain, and we establish several new results for compact groups. In particular, we compute the exact length and depth of every compact simple Lie group, and draw conclusions for arbitrary connected compact Lie groups G. We obtain best possible bounds on the length of G in terms of its dimension, and characterize the connected compact Lie groups that have equal length and depth. The latter result generalizes a well known theorem of Iwasawa for finite groups. More generally, we establish a best possible upper bound on dim G' in terms of the chain difference of G, which is its length minus its depth.

Comprehensive biodiversity analysis via ultra-deep patterned flow cell technology: a case study of eDNA metabarcoding seawater

The characterization of biodiversity is a crucial element of ecological investigations as well as environmental assessment and monitoring activities. Increasingly, amplicon-based environmental DNA metabarcoding (alternatively, marker gene metagenomics) is used for such studies given its ability to provide biodiversity data from various groups of organisms simply from analysis of bulk environmental samples such as water, soil or sediments. The Illumina MiSeq is currently the most popular tool for carrying out this work, but we set out to determine whether typical studies were reading enough DNA to detect rare organisms (i.e., those that may be of greatest interest such as endangered or invasive species) present in the environment. We collected sea water samples along two transects in Conception Bay, Newfoundland and analyzed them on the MiSeq with a sequencing depth of 100,000 reads per sample (exceeding the 60,000 per sample that is typical of similar studies). We then analyzed these same samples on Illumina’s newest high-capacity platform, the NovaSeq, at a depth of 7 million reads per sample. Not surprisingly, the NovaSeq detected many more taxa than the MiSeq thanks to its much greater sequencing depth. However, contrary to our expectations this pattern was true even in depth-for-depth comparisons. In other words, the NovaSeq can detect more DNA sequence diversity within samples than the MiSeq, even at the exact same sequencing depth. Even when samples were reanalyzed on the MiSeq with a sequencing depth of 1 million reads each, the MiSeq’s ability to detect new sequences plateaued while the NovaSeq continued to detect new sequence variants. These results have important biological implications. The NovaSeq found 40% more metazoan families in this environment than the MiSeq, including some of interest such as marine mammals and bony fish so the real-world implications of these findings are significant. These results are most likely associated to the advances incorporated in the NovaSeq, especially a patterned flow cell, which prevents similar sequences that are neighbours on the flow cell (common in metabarcoding studies) from being erroneously merged into single spots by the sequencing instrument. This study sets the stage for incorporating eDNA metabarcoding in comprehensive analysis of oceanic samples in a wide range of ecological and environmental investigations.

Sampling depth of L-band radiometer measurements of soil moisture and freeze-thaw dynamics on the Tibetan Plateau

Knowing the exact sampling depth of microwave radiometry is essential for quantifying the performance and appreciation of the applicability of satellite soil moisture products. We investigate in this study the sampling depth (δSM) of the L-band microwave emission under frozen and thawed soil conditions on the Tibetan Plateau. Two years of diurnal brightness temperature (TBp) measurements at a time interval of 30 min are collected by the ELBARA-III radiometer deployed at a Tibetan meadow site. Vertical profiles of soil temperature and volumetric liquid water content (θliq) are measured simultaneously at soil depths up to 1 m below the surface. The impact of the θliq measured at different depths on the microwave emission simulations is assessed using the τ-ω emission model, whereby the permittivity of frozen and thawed soil is estimated by the four-phase dielectric mixing model. It is found that: 1) the sampling depth for the effective temperature depends on the magnitude of θliq, and is estimated to be, on average, about 50 and 15 cm for the cold dry and wet warm period, respectively, because of the seasonality in θliq; 2) the δSM is determined at 2.5 cm for both frozen and thawed soil conditions during both cold and warm periods, which is shallower than the commonly used θliq measurement depth (i.e. 5 cm) adopted for the in-situ monitoring networks across the globe; 3) the TBp simulations performed with the θliq measurements taken at the estimated δSM of 2.5 cm result in lower unbiased root mean squared errors, about 14% (3.16 K) and 22% (3.36 K) for the horizontal and vertical polarizations respectively, in comparison to the simulations with the θliq measurements taken from 5 cm soil depth; and 4) the θliq retrieved with the single channel algorithm from the ELBARA-III measured vertically polarized TBp are in better agreement with the θliq measured at 2.5 cm than the one measured at 5 cm. These findings are crucial for developing strategies for the calibration/validation as well as the application of satellite based soil moisture products relying on the L-band radiometry.

Endoscopic management of patients with early gastric cancer before and after endoscopic resection: A review.

With the wide application of endoscopic resection for early gastric cancer (EGC) by not only Asian endoscopists but also those from Western countries, reviews on standardized treatment processes before and after endoscopic resection are nevertheless lacking. In this article we provide a narrative review of studies on the selection of appropriate EGC for endoscopic resection and the follow-up strategies for those with histologically confirmed EGC after endoscopic resection. EGC should be comprehensively assessed before endoscopic resection, including its exact margin, invasive depth and risk of lymph node metastasis (LNM). While the curative resection status of EGC may be evaluated after endoscopic resection based on the newly developed eCura system, although this needs to be further verified. Surveillance with endoscopy and computed tomography scan is necessary for patients with an EGC level A or B. An additional endoscopic resection is recommended for patients with a level-C1 EGC. For patients with a level-C2 EGC, close follow-up is suggested for low-risk tumors of level C2 and additional surgery for those at high risks. Further postoperative strategy is suggested based on comprehensive assessment of the risk of LNM, patient's quality of life and wishes.

Arbitrary Crack Depth Profiling Through ACFM Data Using Type-2 Fuzzy Logic and PSO Algorithm

Estimating the shape and depth of cracks presented in metallic structures is one of the main issues of non-destructive testing (NDT) in order to evaluate effectively the structural integrity of a component. The alternating current field measurement (ACFM) technique is one of the most frequently used electromagnetic methods in this regard. Given the experimental nature of NDT methods, fuzzy logic-based methodologies have been widely used for solving the inverse problem. Due to some experimental restrictions, the obtained ACFM signals do not have high certainty. This problem usually leads to a high uncertainty of classical fuzzy rules extracted from low-accuracy ACFM signals. Therefore, applying classical fuzzy membership functions (MFs) exactly with maximum and fixed certainty does not lead to the best crack depth estimation. In this paper, a type-2 fuzzy logic system has been proposed to model the existing uncertainties of ACFM signals with a higher accuracy. Moreover, for regulating the uncertainty parameters of type-2 fuzzy MFs in the proposed model, the particle swarm optimization (PSO) algorithm has been used. Combining PSO with some special features existed in the ACFM signals allows the proposed model to be able to control the certainty of the extracted rules for estimating the exact depth of cracks. Then, the results of the proposed method are compared with the other state-of-the-art techniques for different levels of noise and different crack shapes obtained through simulated and empirical ACFM data. The results show the superiority of the proposed method even in conditions where the training database volume is not adequate.

Designing Smart Sewerbot for the Identification of Sewer Defects and Blockages

Internet of thing (IoT) is a new concept where the term ‘thing’ is associated with the configurable sensors and devices no matter domestic or industrial, whereas bridging up a relationship in between these things and internet protocol is known as Internet of thing. Moreover, the same concept has been introduced in the field of robotics as ‘Internet of Robotic Things (IoRT)’, which is mainly concerned with active sensorization of sensors dully interfaced with any type of robots i.e. autonomous unmanned ground vehicle (UGV). This paper describes the prototyping of an autonomous sewerbot that will not only identify the sewer defects in sewerage pipelines but will also identify the type of blockages using the technique of digital image processing. Furthermore, the deployed configurable sensors will also share the attributes of particular sewerage line on IoT such that temperature, humidity, availability of hazardous gases, exact depth at which it is available and global positioning using GPS module. The paper also provides the brief construction of this mechatronic and amphibian system via which it can extricate the blockages from sewerage lines along with wireless camera surveillance.