Core Extraction Research Articles

Microbial iron cycling during palsa hillslope collapse promotes greenhouse gas emissions before complete permafrost thaw

Reductive dissolution during permafrost thaw releases iron-bound organic carbon to porewaters, rendering previously stable carbon vulnerable to microbial decomposition and subsequent release to the atmosphere. How mineral iron stability and the microbial processes influencing mineral dissolution vary during transitional permafrost thaw are poorly understood, yet have important implications for carbon cycling and emissions. Here we determine the reactive mineral iron and associated organic carbon content of core extracts and porewaters along thaw gradients in a permafrost peatland in Abisko, Sweden. We find that iron mineral dissolution by fermentative and dissimilatory iron(III) reduction releases aqueous Fe2+ and aliphatic organic compounds along collapsing palsa hillslopes. Microbial community analysis and carbon emission measurements indicate that this release is accompanied by an increase in hydrogenotrophic methanogen abundance and methane emissions at the collapsing front. Our findings suggest that dissolution of reactive iron minerals contributes to carbon dioxide and methane production and emission, even before complete permafrost thaw.

A Web Information Extraction Framework with Adaptive and Failure Prediction Feature

The amount of information available on the internet today requires effective information extraction and processing to offer hyper-personalized user experiences. Inability to extract information by using traditional and machine learning techniques due to dynamic changes in website layout pose significant challenges to the technical community to keep up with such changes. The focus of existing machine learning-based information extraction framework is only on information extraction by using core extraction logic that is susceptible to website changes, thus missing out core features such as ability to handle proactive failure prediction and intelligent information extraction capabilities. The aim of this article is to build a robust and intelligent information extraction framework with the ability not only to proactively predict website failure but also automatically extract information using deep-learning techniques using You Only Look Once and Long Short-term Memory (LSTM) networks. The proactive detection using LSTM detects new location of the web page due to layout changes and enables automatic extraction of information of the new web page. A real-world case with retail website for intelligent information extraction and an offline experimentation environment is setup to demonstrate proactive failure prediction and automatic extraction resulting in high failure prediction, precision and recall of object detection and information extraction.

Digital rock physics: Defining the reservoir properties on drill cuttings

Well drilling with core extraction is one of the most expensive procedures in the oil industry. The potential alternative, which may open opportunities for cost-efficient acquisition of petrophysical data, can be an approach based on digital analysis of drill cuttings. The main purpose of this research was to evaluate the possibility of using digital cuttings analysis and rock physics for reservoir properties evaluation. The carbonate samples of core and cuttings were simultaneously collected from the same intervals during the drilling of deviated wells in the Carboniferous reservoir of the oil deposit in the Republic of Tatarstan, Russia. Based on the core analysis using the optical study of thin sections and XRD, we investigated sedimentological and mineralogical features and classified all lithotypes of well intervals. The standard samples were produced from all defined facies and their reservoir properties were studied in routine tests. The largest cuttings from each well interval were separated and their structures were compared using μCT with core subsamples of the same intervals. We assessed the changes of cuttings structure occurring in the drilling process, which include the colmatation of the pore space with drilling fluid and disintegrated rock particles and the formation of secondary fractures. Detailed analysis of cuttings from one well interval consisting of the border between the facies of high porous grainstones with packstones and dense micrite limestones demonstrated that high porous varieties were eroded in the drilling process. The analysis of chemical composition using XRF-mapping, XRD and SEM with EDS showed that most of the cuttings were constituted by disintegrated rock particles or form elements (e.g. separate fusulinids) cemented by drilling mud. However, more durable cuttings from dense micrite limestones facies were generally retained their dominant calcite composition and original rock structure, with only secondary fractures. Finally, we analyzed pore space properties and performed digital simulations of wave propagation velocities to compare the characteristics of these cuttings and core subsamples from this lithotype, scanned in the same μCT settings. The results demonstrate close characteristics of porosity 0.08–0.6%, dominant pore sizes 1–60 μm and velocities Vp = 6130–6240 m/s, Vs = 3180–3230 m/s. However, the comparison of obtained values with measured on standard samples shows a significant difference, which is caused by deviation from REV. The potential use of cuttings for assessing reservoir and petrophysical properties can be possible in case of provision with the factors of cuttings structure alteration, representativity of samples, as well as optimization for these purposes of the drilling process with cuttings selection.

Effects of different concentrations of pineapple core extract and maceration process on free-range chicken meat quality

The tenderisation effects of pineapple (Josephine variety) core extracts on the quality of free-range chicken meat using different maceration concentrations (30%, 50%, and 100%) and duration (15, 25, and 35 min) were analysed. Texture profile analysis, colour, pH, bromelain content, and microbiological analyses of the macerated meat samples were assessed. Broiler breast meat macerated with core extract (100%, 35 min) showed 86% reduction in hardness and the pH decreased from 5.87 to 4.99. The pineapple core extract has great potential as a meat tenderiser thus reduces the agriculture by-product and converts it into natural food ingredients.

Integration-based extraction and visualization of jet stream cores

Abstract. Jet streams are fast three-dimensional coherent air flows that interact with other atmospheric structures such as warm conveyor belts (WCBs) and the tropopause. Individually, these structures have a significant impact on the midlatitude weather evolution, and the impact of their interaction is still a subject of research in the atmospheric sciences. A first step towards a deeper understanding of the meteorological processes is to extract the geometry of jet streams, for which we develop an integration-based feature extraction algorithm. Thus, rather than characterizing jet core line purely as extremal line structure of wind magnitude, our core-line definition includes a regularization to favor jet core lines that align with the wind vector field. Based on the line geometry, proximity-based filtering can automatically detect potential interactions between WCBs and jets, and results of an automatic detection of split and merge events of jets can be visualized in relation to the tropopause. Taking ERA5 reanalysis data as input, we first extract jet stream core lines using an integration-based predictor–corrector approach that admits momentarily weak air streams. Using WCB trajectories and the tropopause geometry as context, we visualize individual cases, showing how WCBs influence the acceleration and displacement of jet streams, and how the tropopause behaves near split and merge locations of jets. Multiple geographical projections, slicing, as well as direct and indirect volume rendering further support the interactive analysis. Using our tool, we obtained a new perspective on the three-dimensional jet movement, which can stimulate follow-up research.

Guide to non-destructive concrete strength assessment: Homogeneity tests and sampling plans

Non-Destructive testing (NDT) of concrete can be used in conjunction with destructive techniques (e.g., coring) for an efficient assessment of concrete strength in existing structures. A major drawback that hinders the efficient use of test measurements is the limited description specified by the relevant standards regarding how the overall investigation program should be carried out. This study discusses two elements of the investigation program: homogeneity of different concrete zones and the locations for core extraction. Different homogeneity measures have been investigated to identify heterogeneous concrete zones using extensive statistical analysis of synthetic datasets. The considered homogeneity measures were: t-test, Kolmogorov-Smirnov (KS) test, earth mover's distance, and Cramér-von Mises distance. The results of the analysis indicated that the earth mover's distance and Cramér-von Mises distance outperform the traditional t-test in the identification of heterogenous concrete zones, and hence, recommended to be used for concrete assessment. Furthermore, different sampling plans of core locations, namely, similarity sampling, cluster sampling, proportional stratified sampling, and post-sampling are investigated through the generation of risk curves as indicators of the estimation quality of each sampling plan. It was found that a reduction in the probability of inaccurate concrete strength estimation is feasible. As such, the utilization of sampling plans in concrete assessment can enhance the reliability of the assessment.

Coal Macrolithotype Distribution and Its Genetic Analyses in the Deep Jiaozuo Coalfield Using Geophysical Logging Data

Coal macrolithotypes are closely correlated with coal macerals and pore–fracture structures, which greatly influence the changes in gas content and the coal structure. Traditional macrolithotype identification in coalbed methane (CBM) wells mostly depends on core drilling observation, which is expensive, time-consuming, and difficult for broken core extraction. Geophysical logging is a quick and effective method to address this issue. We obtained coal cores from 75 wells in the deep regions of the Jiaozuo Coalfield, northern China, quantitatively analyzed the logging cutoff number corresponding to various macrolithotypes, and established natural γ (GR), deep lateral resistivity (LLD), and γ–γ log (GGL) response rules for each coal macrolithotype. The formation mechanisms of different coal macrolithotypes are discussed from the perspective of coal facies and pore structures. The results show that GGL decreased but GR and LLD increased from bright coal to dull coal. Most coal macrolithotypes can be distinguished based on the established thresholds of various logging curves. However, excessively high or low ash yields significantly affect the validity of identification. The vertical coal macrolithotypes attributed to the peat marsh environment in Shanxi Formation mostly comprise three to six sublayers; dull or semi-dull coals are predominant close to the 21 coal seam, and the bright or semi-bright types usually appear in the middle part. The semi-bright and bright coals are usually vitrinite rich, whereas the semi-dull and dull coals are primarily inertinite rich. For pore structure arguments, the highest average specific surface area (SBET) and the total pore volume (VBJH) are found in bright coals, followed by dull and semi-bright coals; those of semi-dull coals are the lowest. However, SBET and VBJH change significantly for different samples, even though the coal macrolithotype is the same. Therefore, the macrolithotype is not the key factor determining the coal parameters of pore structures. Rapid and effective identification of coal macrolithotypes can help determine the CBM enrichment area, the CBM well location, and the exploration horizon.

Identifying old Norway spruce and Scots pine trees by morphological traits and site characteristics

ABSTRACT Old trees are important for biodiversity, and the process of their identification is a critical process in their conservation. However, determining the tree age by core extraction, ring counts, and eventually, cross-dating by means of dendrochronology is labor-intensive and expensive. Here we examine the alternative method of estimating determining tree age by visual characteristics for old Norway spruce and Scots pine trees. We used forest stands previously identified as “Old tree habitats” by visual criteria in Norwegian boreal forests. The efficiency of this method was tested using pairwise comparison of the age of core samples from trees within these sites, and within neighboring sites. Age regression models were constructed from morphological traits and site variables to investigate how accurately old trees can be detected. Cored trees in the Old-tree habitats were on average 41.9 years older than compared to a similar selection of trees from nearby mature forests. Several characteristics such as bark structure, stem taper and visible growth eccentricities can be used to identify old Norway spruce and Scots pine trees. Old trees were often found on less productive sites. Due to the wide range of environments included in the study, we suggest that these findings can be generalized to other parts of the boreal zone.

Antioxidant Activity and Discrimination of Organic Apples (Malus domestica Borkh.) Cultivated in the Western Region of Romania: A DPPH· Kinetics-PCA Approach.

Apple (Malus domestica Borkh.) is one of the most used fruit for beverages in Romania. The goal of the study was to evaluate the antioxidant activity and discrimination of various parts of organic and non-organic apple varieties cultivated in the western region of Romania using the DPPH· kinetics–PCA (principal component analysis) approach. Organic and non-organic apples were subjected to solid–liquid ethanol extraction. Core and shell extracts were mixed with DPPH· and spectrophotometrically monitored at 517 nm. Antioxidant activity and mean DPPH· reaction rate at various time ranges reveal significant differences between organic and non-organic samples, as well as apple parts. Organic core and shell extracts had higher antioxidant activities than the corresponding non-organic samples (74.5–96.9% and 61.9–97.2%, respectively, 23.5–94.3% and 59.5–95.5%). Significant differences were observed for the DPPH· reaction rate for the first ½ min, especially in the presence of organic core extracts (3.7–4.8 μM/s). The organic samples were well discriminated by DPPH· kinetics–PCA, the most important variables being the DPPH· reaction rate for the first time range. This is the first DPPH· kinetics–PCA approach applied for discriminating between organic and non-organic fruits and can be useful for evaluating the quality of such type of fruits.

Investigation of construction material quality and workmanship defects of RC buildings collapsed and severely damaged in the 6.8 Mw Sivrice, Elazığ, Turkey earthquake, January 2020

In the Sivrice, Elazığ, Turkey earthquake on January 24, 2020, 41 people lost their lives, more than 1600 people were injured, 672 buildings collapsed, and around 12600 buildings were severely damaged due to poor construction quality. After such devastating earthquakes, damage assessment and forensic investigations are normally carried out quickly for a judicial process, and material qualities are revealed. However, emotional sensitivity of the victims in the earthquake affected zone and disruptions in key lifeline services such as transportation, electricity supply often make these processes difficult. After the Elazığ earthquake, along with the conventional in-situ core sampling method, concrete pieces were collected from columns of collapsed and severely damaged buildings and transported out of the earthquake zone to overcome these adverse conditions. Unlike in the conventional method where the whole sampling process is carried out in the earthquake zone, the core extraction from the transported concrete pieces was carried out outside the earthquake-affected area. The extracted concrete samples were checked for compliance with the prevailing material standards. Moreover, multiple reinforcing bars of various diameters were also extracted and tested to check their compliance with the standards. Besides, the results of examination of the quality of materials and workmanship used in the construction are also discussed, along with the precautions required to minimize fatalities and damage from similar buildings.

Molecular fingerprints in shales from the Sanhu biogenic gas fields in eastern Qaidam Basin, NW China: Evidence of biodegradation of shale organic matter

This study provides evidence for hopane and sterane biodegradation in shale organic matter (OM) via geochemical characterization of shale extracts from the biogenic gas fields of the Sanhu Depression in eastern Qaidam Basin, NW China. Nineteen immature source rock cores of the upper Pliocene–Quaternary from the study area are divided into two groups based on distinct results of Rock-Eval analysis and molecular fingerprints. Organic-rich group A shales are dominated by the ααα 20R configurations of steranes, diagenetic hopanoids and are lean in the αββ 20S configurations of steranes, C27–C29 diasteranes, C21–C22 pregnanes and C19–C29 tricyclic terpanes. In contrast, organic-poor and sandy shales of group B have much higher hopane and sterane isomerization ratios, higher C21–C22 pregnanes, C27–C29 diasteranes and C19–C29 tricyclic terpanes but diminished diagenetic hopanoids. C29 5α-sterane and C31 αβ-hopane isomer concentrations and isomerization ratios reveal a depth-controlled diagenetic profile in group A samples whereas they are randomly or inversely distributed in group B. Moreover, the C27–C30 25-norhopane series has been identified in group B core extracts but are absent in group A. These differences are mainly ascribed to biodegradation of group B core OM. Regardless of microbial alteration of hopanes and steranes in the shale extracts, no significant biodegradation of n-alkanes has been observed in the extracts of both shale groups. However, instead of reflecting preferential degradation of biomarkers, this difference is caused by lower microbial availability of n-alkanes than the biomarkers in the special pore structure of fine-grained sediments and dilution of biodegraded n-alkane patterns by the newly generated n-alkanes from the shale OM. The rare occurrence of hopane and sterane biodegradation in fine sediments in the Sanhu Depression is ascribed to the low hydrocarbon yields from organic lean group B cores that failed to alter the biodegradation signature, since no similar biodegradation case has been reported in organic-rich biogenic gas source rock systems worldwide. Due to a self-sourced biogenic gas system consisting of frequently interbedded shales and silts/sands, the Sanhu biogenic gases form predominantly in the more porous and permeable rocks represented by group B but with most energy sources for microbial metabolism diffused from adjacent, organic-rich shales represented by group A.

Using non-destructive testing to assess static elastic modulus of a limestone exposed to high temperatures

The determination of static elastic modulus in the laboratory requires rock core extraction and the subsequent testing of the samples by means of standardised uniaxial compressive strength tests. However, this destructive procedure is not always suitable – as in the case of protected historic buildings. In these cases, the static elastic modulus can be obtained from the dynamic elastic modulus, in turn derived from the velocity of ultrasonic waves (a non-invasive and non-destructive test). The relationship between both the dynamic and static moduli of rocks has been extensively addressed in the scientific literature. Furthermore, several researchers have separately studied the evolution of static or dynamic elastic moduli of rocks exposed to high temperatures – although few studies have compared both values. It is well known that the dynamic modulus is generally higher than the static modulus, and the values diverge especially in rocks with a low modulus of elasticity. These differences can be mainly explained by the effect of porosity and the size of cracks in the determination of both parameters. In this research, the relationship between static and dynamic moduli for ‘Borriol’ limestone is studied for samples previously subjected to 200, 400, 600 and 800 °C and then cooled slowly (in air) or quickly (immersed in water). The results show that the static modulus of samples heated up to 600 °C decreased 80.9 and 79.1 % and dynamic modulus decreased 62.5 and 64.8 % for slow and quick cooling samples, respectively. For samples heated to 600 and 800 °C, the static and dynamic moduli are similar. In general, no significant differences between both cooling methods are observed, even though static modulus shows more loss than dynamic modulus. Finally, linear models were used to correlate static and dynamic moduli, providing coefficients of determination of 0.99 and 0.97, for slow and quick cooling, respectively. It is also remarkable that the Edyn/Est rate was smaller than 1 for elastic moduli over 30 GPa (i.e., 105, 200 and 400 °C) and greater than 1 for lower moduli (i.e., 600 and 800 °C). The results obtained can be used to calculate the static elastic modulus of ‘Borriol’ limestone from dynamic modulus determined by non-destructive techniques.

Physicochemical stability of pineapple suspensions: the integrated effects of enzymatic processes and homogenization by shear.

The pineapple (Ananas comosus) is an important tropical fruit in the world market. Its pulp has significant nutritional value while the peel and the core, in spite of being high in dietary fibre and nutrients, are generally considered to be agro-industrial waste. The aim of this research was to evaluate the effect that the integrated enzymatic and shear homogenization processes have on the physicochemical stability of pineapple base suspensions (pulp, core, and peel extract). Initially, an enzymatic hydrolysis process was evaluated with a completely randomized factorial design. Independent variables: incubation time (tinc) (1-4h) and [enzyme] (0-200ppm). Dependent variables: viscosity (μ) and particle sizes (D[3;2] and D[4;3]). The results showed a reduction of (μ) (70.7%), D[3;2] (54.2%), and D[4;3] (61.8%) for the optimized treatment (tinc = 3.2h and [enzyme] = 200ppm) compared to the control (t = 0, without enzyme). The effect of the integrated enzymatic treatment with a serial homogenization process was subsequently evaluated. Independent variables: high-speed homogenization time (t1) (15-20min), recirculation time in high pressure homogenizer (t2) (3-7min), and arabic gum (AG) (0.6-1.0%). Dependent variables: total suspension solids (TSS), zeta potential (ζ), μ, spectral stability index (R), D[3;2], and D[4;3]. The application of the integrated processes of enzymatic treatment and serial homogenization was more effective to be able to obtain a stable pineapple-based suspension. The experimental optimization of multiple responses defined t1 = 16.4min, t2 = 7min, AG = 0.98%, and TSs = 15.7 ± 0.5%, ζ = -23.1 ± 0.4mV, µ = 221 ± 11 cP, D[3;2] = 56.8 ± 2µm and D[4;3] = 120.6 ± 4µm and R = 0.58 ± 0.02 were obtained.

Extracts from Dated Lake Sediment Cores in the Athabasca Oil Sands Region Alter Ethoxyresorufin-O-deethylase Activity and Gene Expression in Avian Hepatocytes.

Increases in oil sands mining operations in the Athabasca oil sands region have resulted in increased concentrations of polycyclic aromatic compounds (PACs) and heavy metals in aquatic systems located near surface mining operations. In the present study, sediment cores were collected from 3 lakes with varying proximity to surface mining operations to determine the differences in PAC concentrations. Sediment cores were separated into 2 sections-current mining (top; 2000-2017) and premining (bottom; pre-1945)-and extracts were prepared for in vitro screening using a well-established chicken embryonic hepatocyte (CEH) assay. Concentrations and composition of PACs varied between sites, with the highest ∑PACs in Saline Lake, 5 km from an active oil sands mine site. The proportion of alkylated PACs was greater than that of parent PACs in the top sediment sections compared with the bottom. Ethoxyresorufin-O-deethylase activity in CEH permitted the ranking of lake sites/core sections based on an aryl hydrocarbon receptor-mediated end point; mean median effect concentration values were lowest for the top cores from Saline Lake and another near-mining operations lake, referred to as WF1. A ToxChip polymerase chain reaction (PCR) array was used to evaluate gene expression changes across 43 target genes associated with numerous toxicological pathways following exposure to top and bottom sediment core extracts. The 2 study sites with the greatest ∑PAC concentrations (Saline Lake and WF1) had the highest gene expression alterations on the ToxChip PCR array (19 [top] and 17 [bottom]/43), compared with a reference site (13 [top] and 7 [bottom]/43). The avian in vitro bioassay was useful for identifying the toxicity of complex PAC extracts associated with variably contaminated sediment cores, supporting its potential use for hotspot identification and complex mixture screening. EnvironToxicol Chem 2021;40:1883-1893. © 2021 SETAC.

Biogenic and eco-benign synthesis of silver nanoparticles using jujube core extract and its performance in catalytic and pharmaceutical applications: Removal of industrial contaminants and in-vitro antibacterial and anticancer activities

Biosynthesis of nanoparticles has been rapidly developed in various fields, due to their broad spectrum of applications in the fields of environmental, pharmacology, and medicine. In this study, facile, rapid, eco-friendly and cost-effective method was used to green synthesis of silver nanoparticles (AgNPs) using jujube core extract (AgNPs- JCE ) and then used as antibacterial, anticancer and catalytic agents. The reaction parameters such as AgNO 3 concentration (1, 5, 10, 20 and 40 mM), reaction time (5, 30 and 60 min) and pH (without pH, 10 and 12) were discussed and optimized. The surface plasmon resonance peak at about 420 nm in the UV–Vis absorption spectrum confirmed the green synthesis of silver nanoparticles. Microscopic results revealed that the synthesized AgNPs- JCE were spherical in morphology with a size range of 25–35 nm.In addition, the subject AgNPs promising catalytic properties in the degradation of pollutants including rhodamine b (RhB) and eriochrome black T (EBT) as cationic and anionic contaminant under UV and visible light irradiations. The photocatalyst (AgNPs- JCE ) exhibited the degradation of 90.9 % and 84.7% for RhB and EBT contaminants after 80 min under UV irradiation, respectively. The antibacterial activities of AgNPs- JCE was checked against E. coli as Gram-positive bacteria and K. pneumoniae and S. aureus as Gram-negative bacteria with MIC and MBC values of (1.26 and 1.26 μ g/ml), (2.5 and 2.5 μ g/ml), and (2.5 and 10 μ g/ml), respectively. Finally, the cytotoxicity of synthesized nanoparticles against AGS as human stomach cancer cell line was determined at several concentrations (2.5, 5, 10, 20, 50, and 100 μ g/ml) using MTT assay. Finding of this research suggested the suitability of AgNPs- JCE as pollutants degradation, antibacterial and anticancer drug development. • First report of biogenic silver nanoparticles synthesis using jujube core extract. • Green synthesized of AgNPs was analyzed by UV/Vis, FT-IR, XRD, EDS, FESEM and TEM. • Exhibited potential photocatalytic degradation in rhodamine b (RhB) and eriochrome black T (EBT) under both UV and sunlight irradiations. • Biosynthesized AgNPs showed good antibacterial activity against gram-positive and gram-negative bacteria. • AgNPs exhibited excellent anticancer activity against AGS as human stomach cancer cell line.

Root biomass and productivity in subtropical arid mangroves from the Gulf of California

Root biomass and productivity research provide valuable information for understanding the ecological processes that occur within mangroves. The data reported by different studies on belowground biomass suggest a high spatial variability, which local factors can control. In this study, the productivity and biomass of belowground roots and pneumatophores of arid mangroves were measured along with sediment and water physical-chemical characteristics in three mangrove zones of the arid region of the Gulf of California, Mexico. Core extraction was performed to measure belowground biomass; in addition, the root productivity was determined using the in-growth core technique, and pneumatophores were sampled at the soil level. Sediment samples were collected monthly to determine texture, pH, bulk density, moisture content, and organic matter. The flood pattern was estimated using piezometers. The study ran from June 2018 to May 2019. An average root productivity was 213.7 g m−2•year−1, with belowground biomass (74.05 ± 15.2 ton•ha−1) and pneumatophores of 5.69 ± 0.92 ton•ha−1. We conclude that the amount of root biomass in arid regions is inverse to the scrub-type mangrove's structural development, which stores up to 70% more than the mangroves in tropical regions. Thus mangroves in arid regions play a role in belowground carbon storage, which depends on multiple variables simultaneously (i.e.: salinity, flood pattern, soil depth, interstitial ORP).

Possible explanations for the predominance of tricyclic terpanes over pentacyclic terpanes in oils and rock extracts

Hopanes and tricyclic terpanes were identified as the dominant terpanes in crude oils and source rock extracts many decades ago. The majority of terpane fingerprints consist of tricyclic terpanes ranging from C19 to C30 (higher members of the tricyclic terpanes are also present but typically not clearly evident due to the abundance of the hopanes) and hopanes ranging from C27 to C35. Within these two families of terpanes, variations will be observed resulting from factors such as source, depositional environments, maturity, biodegradation and migration. However, the most significant departure from a typical tricyclic and hopane type distribution is one entirely dominated by the tricyclic terpanes with the series extending to at least C40 and in many cases, beyond. There are a few reported occurrences of such distributions in the literature, but satisfactory explanations are limited and speculative.Characterization of numerous oils from Devonian-Mississippian age reservoirs in the STACK play in the Anadarko Basin, Oklahoma, has revealed that many of these oils have terpane fingerprints dominated by tricyclic terpanes with the virtual absence of hopanes. It is also of interest to note that there appear to be four additional series of tricyclic terpanes in many of these samples. While attempting to explain these distributions using previously published arguments, it appears there may be other factors at work leading to the dominance of the tricyclic terpanes in this region.This paper discusses previous explanations put forward to explain these somewhat unusual terpane distributions, followed by a brief discussion of the terpane distributions in the STACK oils. Similar distributions of tricyclic terpanes have also been observed in a number of Mississippian rocks in the region, suggesting a possible source for the tricyclic terpanes in these oils. Results from these rock extracts are integrated into the discussion related to the oils.In summary, it appears that maturity is probably the most significant driving force for these distributions, with preferential production of hopanes over the tricyclic terpanes at lower maturity levels. At the higher levels of maturity experienced by the unconventional reservoirs, only tricyclic precursors remain to generate oils dominated by the tricyclic terpanes. At the same time, potential source contributions cannot be ignored, as shown by the presence of extracts dominated by tricyclic terpanes in many of these core extracts.

Identification and analysis of pathological defect appearance in superstructures of reinforced-concrete bridges in Chapare region, Bolivia

The objective of this article is to identify and analyze the main pathological manifestations in bridges in the Chapare - Bolivia region, an area characterized by high humidity and constant rainfall throughout the year. The methodology consisted of the selection of five bridges that showed evident signs of deterioration, in which a visual inspection was carried out and, subsequently, different tests: sclerometer, carbonation depth, penetration of chlorides and core extraction. All the bridges present advanced states of deterioration; highlighting corrosion as the main problem, generating detachment of the concrete and risk of collapse. Although the concrete has a compression strength greater than 30 MPa, the existing carbonation process and the different problems encountered compromises it. It is necessary that the entities in charge provide inspection and maintenance programs according to the environmental and structural characteristics of each bridge.

Extra-Heavy Oil Aquathermolysis Using Nickel-Based Catalyst: Some Aspects of In-Situ Transformation of Catalyst Precursor

In the present work, we studied the catalytic performance of an oil-soluble nickel-based catalyst during aquathermolysis of oil-saturated crushed cores from Boca de Jaruco extra-heavy oil field. The decomposition of nickel tallate and some aspects of in-situ transformation of the given catalyst precursor under the steam injection conditions were investigated in a high-pressure batch reactor using XRD and SEM analysis methods. The changes in physical and chemical properties of core extracts after the catalytic aquathermolysis process with various duration were studied using gas chromatography for analyzing gas products, SARA analysis, GC-MS of saturated and aromatic fractions, FT-IR spectrometer, elemental analysis, and matrix-activated laser desorption/ionization (MALDI). The results showed that nickel tallate in the presence of oil-saturated crushed core under the injection of steam at 300 °C transforms mainly into nonstoichiometric forms of nickel sulfide. According to the SEM images, the size of nickel sulfide particles was in the range of 80–100 nm. The behavior of main catalytic aquathermolysis gas products such as CH4, CO2, H2S, and H2 depending on the duration of the process was analyzed. The catalytic upgrading at 300 °C provided decrease in the content of resins and asphaltenes, and increase in saturated hydrocarbon content. Moreover, the content of low-molecular alkanes, which were not detected before the catalytic aquathermolysis process, dramatically increased in saturates fraction after catalytic aquathermolysis reactions. In addition, the aromatics hydrocarbons saturated with high molecular weight polycyclic aromatic compounds—isomers of benzo(a)fluorine, which were initially concentrated in resins and asphaltenes. Nickel sulfide showed a good performance in desulfurization of high-molecular components of extra-heavy oil. The cracking of the weak C–S bonds, which mainly concentrated in resins and asphaltenes, ring-opening reactions, detachment of alkyl substitutes from asphaltenes and inhibition of polymerization reactions in the presence of catalytic complex reduced the average molecular mass of resins (from 871.7 to 523.3 a.m.u.) and asphaltenes (from 1572.7 to 1072.3 a.m.u.). Thus, nickel tallate is a promising catalyst to promote the in-situ upgrading of extra-heavy oil during steam injection techniques.

Classification of colorectal tissue images from high throughput tissue microarrays by ensemble deep learning methods

Tissue microarray (TMA) core images are a treasure trove for artificial intelligence applications. However, a common problem of TMAs is multiple sectioning, which can change the content of the intended tissue core and requires re-labelling. Here, we investigate different ensemble methods for colorectal tissue classification using high-throughput TMAs. Hematoxylin and Eosin (H&E) core images of 0.6 mm or 1.0 mm diameter from three international cohorts were extracted from 54 digital slides (n = 15,150 cores). After TMA core extraction and color enhancement, five different flows of independent and ensemble deep learning were applied. Training and testing data with 2144 and 13,006 cores included three classes: tumor, normal or “other” tissue. Ground-truth data were collected from 30 ngTMA slides (n = 8689 cores). A test augmentation is applied to reduce the uncertain prediction. Predictive accuracy of the best method, namely Soft Voting Ensemble of one VGG and one CapsNet models was 0.982, 0.947 and 0.939 for normal, “other” and tumor, which outperformed to independent or ensemble learning with one base-estimator. Our high-accuracy algorithm for colorectal tissue classification in high-throughput TMAs is amenable to images from different institutions, core sizes and stain intensity. It helps to reduce error in TMA core evaluations with previously given labels.