Core Extraction Research Articles

Core dataset extraction from unlabeled medical big data for lesion localization

• This work can not only reduce the labeling burden and the training time, but also maintain the performance of the model. • The indicator fusion algorithm can improve the effectiveness of core image extraction. • We propose an iterative optimization selection module to make subsequent batch extraction more accurate. • Comparing with the existing works, this work can work on datasets that are not labeled with any lesion location. With the advancement of technology in the big data era, the amount of data in the medical field has increased considerably, which has promoted the rapid development of intelligent medical diagnoses. Lesion localization plays an indispensable role in the medical field. However, this approach has not been widely applied in realizing intelligent diagnoses. The effect of lesion localization depends on the training of a convolutional neural network, for which a large amount of medical image data with lesion location labeling is required. Although a considerable amount of medical image data is available, the quality varies and most of the data are not labeled in terms of the lesion location. This labeling process is not only time-consuming and laborious but also requires professional knowledge. To solve this problem and facilitate the development of lesion localization, we propose a novel core dataset extraction architecture, which is a general architecture for extracting the core dataset from unlabeled medical big data for lesion localization. In the architecture, the comprehensive core degree of the images is computed by using three evaluation indicators and an indicator fusion algorithm. In addition, we propose an iterative optimization selection module to enhance the performance of the subsequent batch extraction. The experimental results show that the proposed method only needs to extract 30% of the training data to achieve the training effect of the entire training data, thereby considerably reducing the amount of required human resources.

Introducing the metacore concept for multi-target ligand design.

In this work, we introduce the concept of "metacores" (MCs) for the organization of analog series (ASs) and multi-target (MT) ligand design. Generating compounds that are active against distantly related or unrelated targets is a central task in polypharmacology-oriented drug discovery. MCs are obtained by two-stage extraction of structural cores from ASs. The methodology is chemically intuitive and generally applicable. Each MC represents a set of related ASs and a template for the generation of new structures. We have systematically identified ASs that exclusively consisted of analogs with MT activity and determined their target profiles. From these ASs, a large set of 317 structurally diverse MCs was extracted, 127 of which were associated with different target families. The newly generated MCs were characterized and further prioritized on the basis of AS, compound, and target coverage. The analysis indicated that 260 MCs were pharmaceutically relevant. These MCs and the compound and target information they capture are made freely available for medicinal chemistry applications.

Сүйелді қайың (Betula Pendula) ағашын зақымдайтын фитопатогенді бактерияларды молекулалық идентификация тəсілі арқылы анықтап оның филогенетикалық шежіресін құру

The article discusses the morphological changes of birch trees (Betula pendula Roth.) due to bacterial cancer that grow in the artificial forest «Green Belt» surrounding the city of Nur — Sultan. Kernel samples were taken from diseased tree trunks, isolated bacterial cultures were grown in nutrient medium and given cultural and morphological characteristics. Extraction of cores from diseased birch trunks, isolation of pure strains of the pathogen, molecular identification of ribosomal RNA 16S nucleotide chains and comparison of these results with relevant data from the international database Gene Bank are carried out using modern methods in the field of bacteriology and botany. The molecular characteristics of the isolated bacterial strains corresponded to 96.72 % of the typical strain Dickeya dadantii based on the international Gene Bank.

Modeling petroleum generation, retention, and expulsion from the Vaca Muerta Formation, Neuquén Basin, Argentina: Part I. integrating compositional kinetics and basin modeling

Improved understanding and prediction of petroleum expulsion, retention, and producibility from source rocks (SR) are achieved by integrating 3D basin modeling with customized compositional kinetics and retention model for the lower Vaca Muerta Formation (LVM), Neuquén Basin, Argentina. Modeling results indicate basin-wide expulsion from LVM started in the late Cretaceous when petroleum generation exceeded the SR retention capacity at thermal maturity of 0.9–1.0% Ro, associated with increasing pore pressure (Pp), increasing then maintained porosity (ø), permeability (k), and free petroleum retained in the SR (free petroleum). Expulsion ceased around the middle Eocene when kerogen, polar components, and medium aromatics were totally cracked at about 1.1–1.3% Ro. In the late Eocene, a different type of expulsion occurred in deeply buried areas at > 1.3% Ro due to continued cracking of the remaining larger hydrocarbons to form smaller hydrocarbons. The petroleum cracking created volume expansion, which in turn induced rock fracturing, which then reduced Pp, ø, k, and free petroleum. Then, continuous thermal cracking increased Pp and maintained ø, k, and free petroleum. In the mid-Miocene, tectonic uplift stopped the thermal stress and secondary cracking, and decreased pressure and temperature. Modeled petroleum compositions and properties such as gas wetness, oil °API gravity, gas/oil ratio are calibrated to Vaca Muerta (VM) core extracts, produced oils, and mud gases at wells with maturities ranging from oil window to dry gas. Our study indicates larger and polar components are preferentially sorbed within the source rock and cracked through thermal maturation by 1.3%Ro. Genetic saturates/aromatics ratio (S/A) equals about one at <0.8% Ro, and gradually increases in all retained fluids due to preferential generation of saturates and preferential thermal cracking of aromatics, which are mostly consumed by 1.65%Ro. The preferential sorption of aromatics causes a higher S/A in the free oil. The method and the insights of this study improve the fundamental understanding of petroleum expulsion and retention and can be applied to global plays.

Quaternary exhumation history of the NE Tibetan Plateau revealed by peculiar distributions of polycyclic aromatic hydrocarbons in core extracts from the Sanhu depression, eastern Qaidam basin

ABSTRACTReworked organic matter (ROM) has been frequently encountered in fresh organic matter (FOM) in young sedimentary basins. Our study reports an ROM‐dominated sequence from 21 borehole cores of the Late Pliocene–Quaternary strata in the Sanhu depression of the eastern Qaidam basin in northwestern China. Reworked organic matter occurrence is confirmed by Rock‐Eval pyrolysis results, high Ro values, and reversed polyaromatic hydrocarbon (PAH) maturity trends showing elevated maturities. Rock–source correlation using molecular fingerprints of biomarkers shows ROM was derived from Jurassic freshwater lacustrine source rocks dominated by terrestrial input, contrasting the immature Quaternary FOM developed in anoxic, saline lacustrine facies. The ROM provenance is traced northward to the southern Qilian Mountains. Maximum burial depths of ROM prior to erosion have been inferred by a burial depth–Rc (calculated vitrinite reflectance) correlation. Two chronological boundaries (1.83 Ma and 3.12 Ma) displaying distinct biomarker fingerprints are obtained from a previously reported chronological framework in the study area. Accordingly, an eroded thickness of 1214 m and an average erosion rate of 94 cm/ka of the ROM provenance areas during this temporal interval are derived. Our study has illustrated the potential value of geochemical compositions of ROM with constrained provenances in investigating the exhumation history of a mountain.

Geometry-Driven Detection, Tracking and Visual Analysis of Viscous and Gravitational Fingers.

Viscous and gravitational flow instabilities cause a displacement front to break up into finger-like fluids. The detection and evolutionary analysis of these fingering instabilities are critical in multiple scientific disciplines such as fluid mechanics and hydrogeology. However, previous detection methods of the viscous and gravitational fingers are based on density thresholding, which provides limited geometric information of the fingers. The geometric structures of fingers and their evolution are important yet little studied in the literature. In this article, we explore the geometric detection and evolution of the fingers in detail to elucidate the dynamics of the instability. We propose a ridge voxel detection method to guide the extraction of finger cores from three-dimensional (3D) scalar fields. After skeletonizing finger cores into skeletons, we design a spanning tree based approach to capture how fingers branch spatially from the finger skeletons. Finally, we devise a novel geometric-glyph augmented tracking graph to study how the fingers and their branches grow, merge, and split over time. Feedback from earth scientists demonstrates the usefulness of our approach to performing spatio-temporal geometric analyses of fingers.

A Review of MRI Acute Ischemic Stroke Lesion Segmentation

Immediate treatment of a stroke can minimize long-term effects and even help reduce death risk. In the ischemic stroke cases, there are two zones of injury which are ischemic core and ischemic penumbra zone. The ischemic penumbra indicates the part that is located around the infarct core that is at risk of developing a brain infarction. Recently, various segmentation methods of infarct lesion from the MRI input images were developed and these methods gave a high accuracy in the extraction and detection of the infarct core. However, only some limited works have been reported to isolate the penumbra tissues and infarct core separately. The challenges exist in ischemic core identification are traditional approach prone to error, time-consuming and tedious for medical expert which could delay the treatment. In this paper, we study and analyse the segmentation algorithms for brain MRI ischemic of different categories. The focus of the review is mainly on the segmentation algorithms of infarct core with penumbra and infarct core only. We highlight the advantages and limitations alongside the discussion of the capabilities of these segmentation algorithms and its key challenges. The paper also devised a generic structure for automated stroke lesion segmentation. The performance of these algorithms was investigated by comparing different parameters of the surveyed algorithms. In addition, a new structure of the segmentation process for segmentation of penumbra is proposed by considering the challenges remains. The best accuracy for segmentation of infarct core and penumbra tissues is 82.1% whereas 99.1% for segmentation infarct core only. Meanwhile, the shortest average computational time recorded was 3.42 seconds for segmenting 10 slices of MR images. This paper presents an inclusive analysis of the discussed papers based on different categories of the segmentation algorithm. The proposed structure is important to enable a more robust and accurate assessment in clinical practice. This could be an opportunity for the medical and engineering sector to work together in designing a complete end-to-end automatic framework in detecting stroke lesion and penumbra.

Photostability and characterization of spray-dried maltodextrin powders loaded with Sida rhombifolia extract

Sida rhombifolia extracts, obtained by pressurized liquid extraction (PLE), were microencapsulated in maltodextrin (MD) by spray drying. Different formulations were prepared with MD at 20% (w/w) and with 2.5, and 5.0% of S. rhombifolia extract, called ME2.5, and ME5.0, reaching an encapsulation efficiency of 89, and 94%, respectively. Scanning electron microscopy (SEM) and fluorescence microscopy enable the determination of the particles average size of 3.07 μm, and confirmed the extract encapsulation in MD. Besides, the phenolics autofluorescence allowed the correlation with the extract compounds, mainly 3-O-β-D-glycoside . The Fourier transform infrared (FTIR) results show no interaction between the coating material (MD) and the microcapsules core (extract). The produced powder was characterized by colorimetric analyzes, solubility isotherms, kinetics, and moisture adsorption, in addition to thermal analyzes. Thermogravimetry (TG) and Differential Scanning Calorimetry (DSC) indicated 64.6 and 53.4% of mass loss for ME2.5 and ME5.0, respectively. The microparticles photostability, evaluated in a self-assembled UVA/UVB emission chamber, showed 93.8 and 84.5% stabilization of total phenolic compounds (TPC) for ME2.5 and ME5.0, respectively. Given the high encapsulation efficiency and the preservation of extract quality, this study results suggest the possibility to use the loaded microcapsules in formulations for food and nutraceutical industries. • Phenolic compounds from Sida rhombifolia leaves were microencapsulated with spray-dry maltodextrin. • SEM and fluorescence morphological analysis confirm the true encapsulation of the extract by maltodextrin. • A UVA and UVB emission chamber was built, with a temperature sensor and air exhaust system. • The photostability of phenolic compounds present in the microencapsulated extract was evaluated by UVA and UVB emission. • The encapsulation process has shown optimal efficiency and represents good prospects for industrial deployment.

COMBINED METHOD FOR CLEANING PIPES FROM SOIL CORE

The paper is devoted to solving an urgent problem - improving the technology of soil excavation during trenchless pipe laying by vibro-impact pushing with the leading steel casing of the well. A new method for core extraction is proposed, which is based on the effect of its vibration transportation under the influence of combined static-dynamic load. The optimum level of soil moisture is experimentally determined, which contributes to a decrease in lateral friction when it moves along a metal pipe cavity. The results of pilot tests on cleaning a pipe 530 mm in diameter, immersed in soil at full design length of transition using Typhoon-190 pneumatic hammer with a mass of 190 kg are presented. The velocity characteristic of core displacement at changing its moisture content is obtained.

A Sectioning, Coring, and Image Processing Guide for High-Throughput Cortical Bone Sample Procurement and Analysis for Synchrotron Micro-CT.

Bone is a dynamic and mechanically active tissue that changes in structure over the human lifespan. The products of the bone remodeling process have been studied substantially using traditional two-dimensional techniques. Recent advancements in X-ray imaging technology via desktop micro-computed tomography (µCT) and synchrotron radiation micro-computed tomography (SRµCT) have allowed for the acquisition of high-resolution three-dimensional (3D) scans of a larger field of view (FOV) than other 3D imaging techniques (e.g., SEM) providing a more complete picture of microscopic structures within human cortical bone. The specimen should be accurately centered within the FOV, however, to limit the appearance of streak artifacts known to impact data analysis. Previous studies have reported procurement of irregularly shaped rectilinear bone blocks that result in imaging artifacts due to uneven edges or image truncation. We have applied a geological sampling protocol (coring) to procure consistently sized cortical bone core specimens for SRµCT experiments from the anterior aspect of human femora. This coring method is efficient and minimally destructive to tissue. It creates uniform cylindrical samples that decrease imaging artifacts by nature of being isometric during rotation and providing a uniform path length for X-ray beams throughout scanning. Image processing of X-ray tomographic data of cored and irregularly shaped samples confirms the potential of the technique to improve visualization and analysis of cortical bone microarchitecture. A goal of this protocol is to deliver a reliable and repeatable method for the extraction of cortical bone cores that is adaptable for various types of high-resolution bone imaging experiments. An overarching goal of the work is to create a standardized cortical bone procurement for SRµCT that is affordable, consistent, and straightforward. This procedure may further be adapted by researchers in related fields who commonly evaluate hard composite materials such as in biological anthropology, geosciences, or material sciences.

ВЛИЯНИЕ КАЧЕСТВА БЕТОННЫХ РАБОТ НА ПРОЧНОСТЬ БЕТОНА МОНОЛИТНЫХ КОНСТРУКЦИЙ

the production of concrete works in the construction of monolithic frames of buildings and structures is associated with a large number of technological operations and the corresponding dependence of the quality of the products obtained from the culture of construction production and the level of its control. In many cases, concreting is carried out with some deviations from the technical regulations governing the preparation and laying of the concrete mix, which has a negative impact on the consumer characteristics of the structure, first of all, on strength. It is known that the most common methods of industrial control of the quality of concrete work are destructive tests of concrete samples laid in control cubes together with the constructed structure and non-destructive testing of concrete of the strength that has gained strength. However, even qualitatively and timely carried out control measures do not guarantee the achievement of design-controlled design strength throughout the volume, since control cubes are prepared for testing under ideal conditions of laying and concrete set of strength not observed in the design, and non-destructive methods determine the strength of near-surface layers of concrete, which allows judging reliably the strength of the material throughout the volume of the structure. Especially these circumstances relate to the most massive and, at the same time, the most important for the structural safety of the whole building frame structures – monolithic foundation slabs. The difference between the actual strength of the slabs extracted from the slab during the production of the construction and technical expertise of concrete cores depends significantly on the depth of core extraction, while the design of the slab is always carried out on the assumption of an equal strength of the concrete along the depth of the structure, which is obviously the source of the potential limited availability of foundation plates and the cause of the appearance of numerous defects in the construction and operation of structures of the above-foundation part of the frame. The paper presents experimental studies of the authors to determine the actual difference in concrete strength from the depth of foundation slabs and quantifies it.

Characterizing the Water Storage Capacity and Hydrological Role of Mountain Peatlands in the Arid Andes of North-Central Chile

High-altitude peatlands in the Andes, i.e., bofedales, play an essential role in alpine ecosystems, regulating the local water balance and supporting biodiversity. This is particularly true in semiarid Chile, where bofedales develop near the altitudinal and hydrological limits of plant life. The subterranean geometry and stratigraphy of one peatland was characterized in north-central Chile using Electrical Resistivity Tomography (ERT), Ground Penetrating Radar (GPR) and core extraction. Two sounding locations, two transversal and one longitudinal profile allowed a 3D interpretation of the bofedal’s internal structure. A conceptual model of the current bofedal system is proposed. Geophysical results combined with porosity measurements were used to estimate the bofedal water storage capacity. Using hydrological data at the watershed scale, implications regarding the hydrological role of bofedales in the semiarid Andes were then briefly assessed. At the catchment scale, bofedal water storage capacity, evapotranspiration losses and annual streamflow are on the same order of magnitude. High-altitude peatlands are therefore storing a significant amount of water and their impact on basin hydrology should be investigated further.

Post-well stimulation allocation of commingled production using geochemical fingerprinting techniques in unconventional reservoirs: A review of methods, and a case study of the Montney Formation, Western Canadian Sedimentary Basin

The methods used in allocating commingled production in conventional reservoirs are similar to those that are effective in performing the same task on unconventional reservoirs. However, the protocols to follow can vary a great deal. The presence of distinct endmembers in the former allows the use of the method of production allocation using peak height ratios and mixing curves and using linear regression of peak heights. Due to the possible contribution from multiple intervals in the same formation or even from different formations as in the case of fracture stimulated unconventional reservoirs, the combined application of methods that compare the quantities and carbon stable isotopes of selected compounds (such as saturate and aromatic hydrocarbons) and other parameters (such as API gravity) was employed. This was done based on a series of samples presumed to represent the endmembers via their HRGC and GCMS oil fingerprint, followed by the determination of the contribution from each sample by using an algebraic solution of simultaneous linear equations. A review of the two methods is provided.The aforementioned method for unconventional resources is demonstrated in a case study of production allocation that was performed on three produced oils sampled at different times from three separate wells, “A” “C”, and “D”, located in the Western Canadian Sedimentary Basin. A total of 25 core extract samples representing two producing zones (end members) of the Montney Formation (i.e., the Middle and the Lower Montney) from well “A” and “B” were used. Results of GC and GCMS analyses of the samples were evaluated; rigorous filters, cluster analysis (dendrograms), and Principal Component Analysis (PCA) were applied to identify any clustering or variation between the samples representing possible contributor layers and the commingled oil. Then, using proprietary software and statistical techniques, the fingerprint of selected compounds was qualitatively compared and their quantity in each of the rock extracts and the produced oils was determined in order to allocate the contribution from the two end members that each extract belongs to.Results from the method for unconventional resources were compared to other data (such as GC trace patterns) for consistency. The case study demonstrates that a combined approach that accounts for the entire fingerprint (i.e., GC and molecular markers (including biomarker and non-biomarker parameters)), produces the best results and minimizes uncertainty.

A reversed compositional pseudo-gradient in biodegraded oil column from Liaohe Basin, NE China

Abstract Most heavy oils or tar sands are formed by microbial biodegradation and show a compositional gradient toward the base of oil column. However, a reversed pseudo-gradient has been observed from the fourth member of the Shahejie Formation in Shuguang oilfield, Liaohe Basin, NE China, on the basis of bulk and molecular compositions in a series core extracts from well K037. The bulk compositions show systematic depletion of saturated hydrocarbons and enrichment of polars (resins + asphaltenes) toward the top of the oil column. Molecular compositions illustrate that these extracts have similar source input, depositional environment and thermal maturity, and their compositional differences are mainly caused by varying degrees of biodegradation. Biodegradation removes all n-alkanes, most isoprenoid alkanes, partial alkylnaphthalenes and alkylphenanthrenes at the top of oil column, whereas only n-alkanes are affected at the bottom. Reservoir temperature has no crucial impact on biodegradation levels as the whole oil column in the temperature range of 41–44 °C is ideal for microbial activities. The studied reservoir is not a continuous oil column, which is separated by a few barriers and baffles. The occurrence of locally high-water saturation layers caused multiple small gradients in the mid and lower part of oil column with a normal biodegradation gradient in the lowermost compartmentalized interval. The overall reversed compositional pseudo-gradient is controlled by a generally upward coarsening sedimentary sequence and the existence of top water situated at a lithology change boundary from coarse sandstones and conglomerates to fine grained sandstones. This study provides a new perspective to assess the reservoir fluid heterogeneity and sheds the light on sweet spots identification for heavy oil exploration and development.

Evaluation of dissolution of purified bromelain from pineapple core extract (Ananas comosus [L.] Merr) in the form of chitosan-coated microspheres

The aim of this study is to coat the bromelain from pineapple’s core into chitosan microspheres crosslinked by glutaraldehyde to maintain its activity until it reaches the intestines. The crude enzyme was first purified by ammonium sulfate precipitation method, followed by the dialysis. The bromelain fraction of the dialysis has a specific activity of 294.44 U/mg with a purity level of 15.68 fold compared to the crude enzyme. Coating bromelain using glutaraldehyde crosslinked microsphere showed an efficiency of 87.14 %. The dissolution test results showed the release rate of bromelain in artificial gastric fluid is 9.35 % and in artificial intestinal environment is 79.92 %. The result of this study indicates that chitosan-coated microspheres are good enough as bromelain coatings for slow-release matrices.

Compression resistance of repaired structural concrete elements after core extraction

Abstract Core sampling for testing is considered a reliable method to provide information on structural materials and is one of the most implemented techniques in the evaluation of concrete elements. However, core drilling results in a decrease in cross section that can compromise structural mechanical strength even if the extracted section is repaired. Norm NBR 7680-1 recommends dry pack as a repair method but also allows the use of other techniques as long as its effectiveness is proven. This work evaluated the resistance of repaired structural prototypes after core drilling sampling. Concrete blocks with 20 MPa resistance were produced from which cores of 100 mm, 75 mm and 50 mm in diameter were extracted. The blocks were repaired with 20 MPa concrete, grout and dry pack techniques. The reconstitution with concrete showed poorest performance, while dry pack led to strengths even higher when compared to reference values.

Measuring the Strength of Root-Reinforced Soil on Steep Natural Slopes Using the Corkscrew Extraction Method

Roots can help to stabilise slopes against landslides and anchor trees against wind loading, but their mechanical contribution to the strength of soil is difficult to rapidly quantify under field conditions. A new field measurement method, quantifying the shear strength of rooted soil by measuring the resistance against extraction of soil cores using a large corkscrew device, was tested across three heterogeneous slopes (unforested, forested and clearfelled) in Scotland. The presence of roots significantly increased the measured shear strength in the surface layer of the Sitka spruce forested slope. Differences in strength between the three areas were however not significant. This could be attributed to the large variation in the soil component of the combined root–soil shear strength, which was strongly affected by variations in both soil density and gravel content. Measured strength on these natural slopes were much more variable compared to previously investigated sites. These results highlight the importance of investigating the variation in soil strength during root-reinforcement measurements, and furthermore demonstrate the need for a sufficiently large number of tests to address this variation. The corkscrew provides rapid estimation of root-reinforced soil shear strength on sites with difficult accessibility. Compared to the more conventional shear vane method, which yielded comparable soil strength results, the corkscrew proved more suitable in stony soil layers and has the additional benefit of simultaneously extracting small (rooted) soil samples that could be used for further root and soil analysis. It therefore proved a useful and effective field tool for use when a rapid estimation of root-reinforced soil shear strength is required.

Sampling Methods for Luminescence Dating of Subsurface Deposits from Cores.

Study of subsurface deposits often requires coring or drilling to obtain samples for sedimentologic and geochemical analysis. Geochronology is a critical piece of information for stratigraphic correlation and rate calculations. Increasingly, luminescence dating is applied to sediment cores to obtain depositional ages. This paper provides examples and discussion of guidelines for sampling sediment core for luminescence dating. Preferred protocols are dependent on the extraction method, sedimentology, core integrity, and storage conditions. The methods discussed include subsampling of sediment in opaque core-liners, cores without liners, previously open (split) cores, bucket auger samples, and cuttings, under red lighting conditions. Two important factors for luminescence sampling of sediment core relate to the integrity of the natural luminescence signal and the representation of the dose rate environment. The equivalent dose sample should remain light-safe such that the burial dose is not reset (zeroed) by light exposure. The sediment sampled for dose rate analyses must accurately represent all units within at least 15 cm above and below the equivalent dose sample. Where lithologic changes occur, units should be sampled individually for dose rate determination. Sediment core extraction methods vary from portable, hand-operated devices to large truck- or vessel-mounted drill rigs. We provide recommendations for luminescence sampling approaches from subsurface coring technologies and downhole samplers that span shallow to deep sample depths.

Defining a supergiant petroleum system in Brazil’s Santos Basin with multidisciplinary methods: One template for exploration success

Is there a petroleum system here? How extensive and effective is it? How is it defined? Although we had presented a 2005 AAPG poster to address these questions, we now have performed an exploration look-back or case study demonstrating basin-wide presalt charge across Brazil’s Santos Basin. Santos has been a disappointing gas province with meager results compared to the adjacent Campos Basin for the past two decades. We have reviewed and expanded presentations at AAPG and SEG conferences from 1998 to 2005, which were followed 17 months later by the supergiant Tupi discovery, now Lula Field. We document the progression of analyses and revision of interpretations as a case history for multidisciplinary work in a frontier region with, at the time, scant coverage of key data types. Despite our access to a broad range of material (oil and cuttings samples, piston core extracts, slicks analysis, regional seismic lines, potential field coverages, and published literature), only a handful of point samples directly fitted our hypothesis of a mature oil-prone presalt source, supported by our inference, from leakage at the basin margins, of basin-wide migration and charge. Although the volumes of data collected across the Santos Basin are orders of magnitude larger in 2019, with a concomitant improvement in understanding the petroleum system and overall basin evolution, we take pains to limit our focus to what was known as of mid-2005 (although perhaps published later), which still sufficed to point to the future success. Because the source presence and effectiveness are the first consideration in evaluating frontier basins, our methodology provides one template for understanding a key geologic risk. We emphasize the importance of careful screening of inputs when information is scant and thus erroneous inferences are easily reached, with the need to take an exploration inference wherever data, once cross-validated, direct the explorer.

Investigating significance of various parameters affecting capacity of core drilled columns for safe core extraction

Infrastructures which are constructed with inadequate quality control and design requirements or are later being subjected to different usage away from its intended purpose are vulnerable to premature structural failure. A proper detailed engineering assessment (DEA) becomes immensely important when a structure falls in this hazard category in order to determine possible modes of retrofitting. Evaluation of in-situ concrete strength through drilling cores is considered as a relatively precise and reliable mean of obtaining material property for DEA. However, the negative impact of extracting cores on structural components has seldom been addressed in previous studies, thereby causing concerns for engineers. The effect is more prominent for low-strength structures which are usually the case for vulnerable structures requiring assessment. Hence, a study has been undertaken to obtain a quantitative evaluation of parameters affecting the capacity of columns subjected to core extraction. Several parameters, such as column size, compressive strength, lateral tie spacing, core dimension and location have been considered within the study. Finite element models, being validated by comparison with capacities of lab-scale core drilled columns, have been used to analyse the effect of these parameters on column strength. The obtained significant influence of each parameter on column performance has been utilized in developing quantitative generalized graphical guidelines. The graphical guidelines will aid practicing engineers in selecting specific core sizes coherent with other structural parameters obtained from drawings or site visit while abiding by the determined safety limit.