Editorial: Rock physics modeling and well-log practice for unconventional reservoirs

Unconventional resources with commercial interest in the world mainly include heavy oils, shales, coalbed methane and tight gas sands. The production and development of these resources have changed the supply pattern of global energy. Quantitative interpretation of geophysical data in the exploration, well logging and engineering development of the unconventional resources requires a comprehensive understanding of the physical properties of rocks and their relationships. The research of rock physics provides an interdisciplinary treatment of physical properties, whether it is highly related to geological, geophysical and geomechanical methodologies. The development of new rock physics methods is essential when integrating core, well-log, seismic data to improve the accuracy of formation evaluation and reservoir characterization. In this Research Topic, it includes 10 articles addressing a variety of rock physics studies on unconventional resources, highlighting fundamental theories, laboratory work and well-log interpretation. . .

Acoustic emission source location method and experimental verification for structures containing unknown empty areas

Acoustic emission (AE) localization plays an important role in the prediction and control of potential hazardous sources in complex structures. However, existing location methods have less discussion on the presence of unknown empty areas. This paper proposes an AE source location method for structures containing unknown empty areas (SUEA). Firstly, this method identifies the shape, size, and location of empty areas in the unknown region by exciting the active AE sources and using the collected AE arrivals. Then, the unknown AE source can be located considering the identified empty areas. The lead break experiments were performed to verify the effectiveness and accuracy of the proposed method. Five specimens were selected containing empty areas with different positions, shapes, and sizes. Results show the average location accuracy of the SUEA increased by 78% compared to the results of the existing method. It can provide a more accurate solution for locating AE sources in complex structures containing unknown empty areas such as tunnels, bridges, railroads, and caves in practical engineering

Synergetic effect on methylene blue adsorption to biochar with gentian violet in dyeing and printing wastewater under competitive adsorption mechanism

Decolorization of dyeing/printing wastewater by carbon-based materials has been carried out to study the adsorption of dye molecules onto adsorbent. Biomass-derived activated carbon (SAC) was sampled from cornstalk pyrolysis in the presence of K2CO3 as an activator. Adsorption of methylene blue (MB) and gentian violet (GV) onto SAC was examined to probe the mechanisms, isotherms, and kinetics of dye removal in single- or two-component systems. According to the adsorption rate in a single-component system, three stages were identified. The equilibrium adsorption capacity for MB onto SAC in the single-component system is 274.84 mg g−1 which is higher than that for GV of 266.57, meanwhile the pseudo-second-order (PSO) model would describe the adsorption kinetics with the correlation coefficient higher than 0.99. In the binary GV-MB system, presence of GV promoted MB adsorption to 325.15 mg g−1 and 287.73 mg g−1 at different GV concentrations while the PSO model was also applicable. Furthermore, differences between experimental and calculated values by the Freundlich and Langmuir isotherms indicated the occurrence of competitive adsorption in the two-component system. The gained insights are beneficial for removing the multiple dyes from industrial wastewater, economically and effectively and thus paving the way to the establishment of a greener society

Epigenetic modification and inheritance in sexual reversal of fish

Environmental sex determination (ESD) occurs in divergent, phylogenetically unrelated taxa, and in some species, co-occurs with genetic sex determination (GSD) mechanisms. Although epigenetic regulation in response to environmental effects has long been proposed to be associated with ESD, a systemic analysis on epigenetic regulation of ESD is still lacking. Using half-smooth tongue sole (Cynoglossus semilaevis) as a model—a marine fish that has both ZW chromosomal GSD and temperature-dependent ESD—we investigated the role of DNA methylation in transition from GSD to ESD. Comparative analysis of the gonadal DNA methylomes of pseudomale, female, and normal male fish revealed that genes in the sex determination pathways are the major targets of substantial methylation modification during sexual reversal. Methylation modification in pseudomales is globally inherited in their ZW offspring, which can naturally develop into pseudomales without temperature incubation. Transcriptome analysis revealed that dosage compensation occurs in a restricted, methylated cytosine enriched Z chromosomal region in pseudomale testes, achieving equal expression level in normal male testes. In contrast, female-specific W chromosomal genes are suppressed in pseudomales by methylation regulation. We conclude that epigenetic regulation plays multiple crucial roles in sexual reversal of tongue sole fish. We also offer the first clues on the mechanisms behind gene dosage balancing in an organism that undergoes sexual reversal. Finally, we suggest a causal link between the bias sex chromosome assortment in the offspring of a pseudomale family and the transgenerational epigenetic inheritance of sexual reversal in tongue sole fish

Eco-friendly and stable silver bismuth disulphide quantum dot solar cells via methyl acetate purification and modified ligand exchange

From the point of view of environmentally-friendly, non- or less toxic photovoltaic material and fabrication method are desired by both the academia and industrial community. However, most efficient quantum dot solar cells have been fabricated based on heavy metal and toxic solvent consumption, which could cause serious ecological problems. Quantum dot solar cells were studied and explored based on lead-free active material silver bismuth disulphide, less toxic solvent purification of methyl acetate and lab-developed ligand exchange process. Twice ligand exchanges with tetramethylammonium iodide were applied for every deposited quantum dot layer kept in static. Methanol rinse was applied to the quantum dot film after each ligand exchange process to promote the ligand exchange and clean the organic residuals. Decent power conversion efficiency and good stability were demonstrated for the fabricated silver bismuth disulphide quantum dot solar cells. The best power conversion efficiency of 4.57% was achieved, with open-circuit voltage of 0.445 V, short-circuit current of 18.87 mA/cm(2) and fill factor of 54.4%. Over 95% of the original power conversion efficiency was maintained after 150 days both in N-2-filled glove box and ambient atmosphere with relative humidity of 30%. This work demonstrated fabrication of quantum dot solar cells based on non- or less-toxic quantum dots and solvent consumption. Which would benefit the development and commercialization of quantum dot solar cell technology. (C) 2019 Elsevier Ltd. All rights reserved

Effect of Abnormal Grains on the Mechanical Properties of FGH96 Solid-State Diffusion Bonding Joint

The hollow twin-web disk is designed to improve the thrust-to-weight ratio of the aero engine, where the welding joint microstructures determine the disk’s mechanical properties. This study aimed to elucidate the effect of abnormal grains formed in the welding region on the mechanical properties of FGH96 solid-state diffusion bonding joints. Digital image correlation using images captured by scanning electron microscopy (SEM-DIC) and electron backscattering diffraction (EBSD) technologies were applied. The results show that abnormally large grains (2.5 times that of the matrix), with preferred orientation in the bonding region, were detrimental to the joint mechanical properties. The yield and tensile strengths were 995.85 MPa and 1456.67 MPa, respectively, and the corresponding relative (ratio to the matrix) ones were 92.54% and 88.81%. After modifying the bonding process, the grain size in the bonding region was tailored to close to that of the matrix, and considerable twin boundaries (TBs) formed, leading to the relative tensile and yield strength reaching 98.86% and 99.37%. Furthermore, the failure mode changed to intragranular type from intergranular type. It demonstrates that tailoring the newborn grain size, introducing TBs inside, and eliminating preferred orientation during the welding process can be an efficient way to improve the joint mechanical properties

Occurrence Characteristics of Lead–Zinc Mine and Low-Flying Aeromagnetic Prospecting in a Forested Region of Yichun City

Understanding the characteristics of lead–zinc mine occurrences and mastering effective investigative techniques are paramount in modern ore prospecting. This research focuses on the forested region of Yichun city in China, with a specific emphasis on the strategic mineral resource of a lead–zinc mine. The study examines the distribution patterns of this mineral and employs advanced aeromagnetic exploration methods. Firstly, we analyzed the geological structure and features of the region by leveraging the latest high-precision aeromagnetic data collected using dynamic delta wing technology. This analysis was complemented by an assessment of the geological conditions of the research area, existing lead–zinc deposits, ground magnetic surveys, and verification studies. With the goal of establishing a meaningful correlation between aeromagnetic anomalies and lead–zinc deposits, we employed various potential field conversion techniques, including the reduction to the pole, vertical derivatives, upward continuation, and residual anomaly analysis techniques. Secondly, we investigated the metallogenic sites within this region and provided a comprehensive summary of the metallogenic circumstances and characteristics related to aeromagnetic prospecting. Thirdly, we employed human–computer interaction fitting inversion techniques to predict the potential for lead–zinc mine prospecting in areas exhibiting aeromagnetic anomalies. The study underscores the significance of high-amplitude and large-scale aeromagnetic anomalies in the study area. Furthermore, we examined the interplay between intrusive rocks, strata, and structural elements within the region to identify favorable conditions for lead–zinc mineralization. As a result of our analysis and discussions, a location was predicted where a lead–zinc mine may exist. The research methodology outlined in this article provides valuable insights for future lead–zinc mine exploration efforts in areas characterized by similar geological conditions

Efficient organic solar cells employing ytterbium ion-doped zinc oxide as cathode transporting layer

Rare earth ions possess highly conductive, magnetic, electrochemical and luminescent properties, multiple valence electrons and long lifetime of excited state, thus could be alternatives as dopant to tune and promote the cathode interlayer property in solar cells. In this work, we study the modification of cathode interlayer by rare earth ion doping, based on the model of Yb doped ZnO by sol-gel method. A relative low doping concentration (below 1%) can improve the electron transport of ZnO and the solar cell performance. This is also confirmed by the obtained photocurrent density, excitons generation rate and electron mobility of device. The best PCE 11.04% (with V-OC 0.940 V, J(SC) 16.58 mW cm(-2), FF 70.7%) is achieved with 0.5% Yb doping, based on PBDB-T:IT-M active layer, compared to the reference PCE of 10.19% with pure ZnO ETL. While with concentration over 1%, the Yb doping decreases the device performance

Parameters in planar quantum dot-polymer solar cell: Tuned by QD Eg, ligand exchange and fabrication process

Parameters in planar quantum dot-polymer solar cell: Tuned by QD Eg, ligand exchange and fabrication proces

Table1_Potential antagonistic relationship of fgf9 and rspo1 genes in WNT4 pathway to regulate the sex differentiation in Chinese giant salamander (Andrias davidianus).DOC

Farmed chinese giant salamander (Andrias davidianus) was an important distinctive economically amphibian that exhibited male-biased sexual size dimorphism. Fgf9 and rspo1 genes antagonize each other in Wnt4 signal pathway to regulate mammalian gonadal differentiation has been demonstrated. However, their expression profile and function in A. davidianus are unclear. In this study, we firstly characterized fgf9 and rspo1 genes expression in developing gonad. Results showed that fgf9 expression level was higher in testes than in ovaries and increased from 1 to 6 years while rspo1 expression was higher in ovaries than in testes. In situ hybridization assay showed that both fgf9 and rspo1 genes expressed at 62 dpf in undifferentiated gonad, and fgf9 gene was mainly expressed in spermatogonia and sertoli cells in testis while strong positive signal of rspo1 was detected in granular cell in ovary. During sex-reversal, fgf9 expression was significantly higher in reversed testes and normal testes than in ovaries, and opposite expression pattern was detected for rspo1. When FH535 was used to inhibit Wnt/β-catenin pathway, expression of rspo1, wnt4 and β-catenin was down-regulated. Conversely, expression of fgf9, dmrt1, ftz-f1 and cyp17 were up-regulated. Furthermore, when rspo1 and fgf9 were knocked down using RNAi technology, respectively. We observed that female biased genes were down regulated in ovary primordial cells after rspo1 was knocked down, while the opposite expression profile was observed in testis primordial cells after fgf9 was knocked down. These results suggested that fgf9 and rspo1 played an antagonistic role to regulate sex differentiation in the process of the gonadal development and provided a foundation for further functional characterizations. The data also provided basic information for genome editing breeding to improve the Chinese giant salamander farming industry.</p