A novel indirect optical method for rock stress measurement using microdeformation field analysis

Stress measurement plays a crucial role in geomechanics and rock engineering,especially for the design and construction of large-scale rock projects.This paper presents a novel method,based on the traditional stress relief approach,for indirectly measuring rock stress using optical techniques.The proposed method allows for the acquisition of full-field strain evolution on the borehole’s inner wall before and after disturbance,facilitating the determination of three-dimensional(3D)stress information at multiple points within a single borehole.The study focuses on presenting the method’s theoretical framework,laboratory validation results,and equipment design conception.The theoretical framework comprises three key components:the optical imaging method of the borehole wall,the digital image correlation(DIC)method,and the stress calculation procedure.Laboratory validation tests investigate strain field distribution on the borehole wall under varying stress conditions,with stress results derived from DIC strain data.Remarkably,the optical method demonstrates better measurement accuracy during the unloading stage compared to conventional strain gauge methods.At relatively high stress levels,the optical method demonstrates a relative error of less than 7%and an absolute error within 0.5 MPa.Furthermore,a comparative analysis between the optical method and the conventional contact resistance strain gauge method highlights the optical method’s enhanced accuracy and stability,particularly during the unloading stage.The proposed optical stress measurement device represents a pioneering effort in the application of DIC technology to rock engineering,highlighting its potential to advance stress measurement techniques in the field.

A three-dimensional numerical study on the stability of layered rock spillway tunnels in alpine canyon areas

Rock masses in alpine canyon areas exhibit strong heterogeneity,discontinuity,and are subject to strong tectonic effects and stress unloading,leading to extremely complex distribution of in-situ stress.In addition,the occurrence of layered rock masses makes it more complex,with obvious anisotropic mechanical properties.This study proposes a comprehensive method for evaluating the stability of layered rock spillway tunnels in a hydropower station in an alpine canyon.First,the failure criterion and mechanical model of layered rock masses considering the anisotropy induced by the bedding plane and the true triaxial stress regime were established;an inversion theory and calculation procedure for in-situ stress in alpine canyon areas were then introduced.Finally,by using a self-developed numerical tool,i.e.CASRock,the stability of the layered rock spillway tunnel in a hydropower station was numerically analyzed.The results show that,affected by geological structure and stratigraphic lithology,there is significant differentiation in the in-situ stress in alpine canyons,with horizontal tectonic stress as the main factor.The occurrence of layered rock masses in the region has a significant impact on the stability of surrounding rock,and the angle between the bedding strike and the tunnel axis as well as the bedding dip both exert a significant influence on the failure characteristics of the surrounding rock.

Relationship Research of PPAR-γ Gene Polymorphisms with Adiponectin and Leptin in Type 2 Diabetes Mellitus

Objective:To investigate the peroxisome proliferator-activated receptor-γ (peroxisome)in patients with type 2 diabetes mellitus.Proliferators-activated receptors-γ ,PPARs-γ (γ )gene.polymorphisms about serum lipofuscin and leptin.Methods:One humdred and twenty patients with type 2 diabetes admitted to our hospital from June 2015 to June 2018 were selected.The patients were divided into an obese group and a non-obese group of 60 patients each according to their waist circumference.A polymerase chain reaction-length polymorphism protocol was implemented in all patients to explore the PPAR-γ gene polymorphism and blood glucose,lipid,adiponectin and leptin levels were measured in both groups.Results:PPAR-γ gene polymorphisms in type 2 diabetic patients were dominated by wild-type homozygous;The levels of total cholesterol,triglyceride and LDL cholesterol in the obese group were significantly higher than those in the non-obese group,while the levels of HDL cholesterol were lower than those in the non-obese group.There is significant difference in comparison between groups(P<0.05)Those canrying the A alele had a significant lipid disorder profile and decreased adiponectin levels.Conclusions:PPAR-γ gene polymorphisms in type 2 diabetes are not significantly associated with adiponectin and leptin,and only in the obese group,the patients with the Allele A showed significant dyslipidemia and a declining trend of adiponectin levels.

Integrated approach of predicting rock stability in high mountain valley underground caverns

High mountain valleys are characterized by the development of intricate ground stress fields due to geological processes such as tectonic stress,river erosion,and rock weathering.These processes introduce considerable stability concerns in the surrounding rock formations for underground engineering projects in these regions,highlighting the imperative need for rigorous stability assessments during the design phase to ensure construction safety.This paper introduces an innovative approach for the pre-evaluation of the stability of surrounding rocks in underground caverns situated within high mountain valleys.The methodology comprises several pivotal steps.Initially,we conduct inverse calculations of the ground stress field in complex geological terrains,combining field monitoring and numerical simulations.Subsequently,we ascertain stress-strength ratios of the surrounding rocks using various rock strength criteria.To assess the stability characteristics of the surrounding rocks in the 1^(#)spillway cave within our project area,we employ numerical simulations to compute stress-strength ratios based on different rock strength criteria.Furthermore,we undertake a comparative analysis,utilizing data from the 5^(#)Underground Laboratory(Lab 5)of Jinping II Hydropower Station,aligning the chosen rock strength criterion with the damage characteristics of Lab 50s surrounding rocks.This analysis serves as the cornerstone for evaluating other mechanical responses of the surrounding rocks,thereby validating the pre-evaluation methodology.Our pre-evaluation method takes into account the intricate geological evolution processes specific to high mountain valleys.It also considers the influence of the initial geostress field within the geological range of underground caverns.This comprehensive approach provides a robust foundation for the analysis and assessment of the stability of surrounding rocks,especially in high mountain valley areas,during the design phase of underground engineering projects.The insights derived from this analysis hold substantial practical significance for the effective guidance of such projects.

Harnessing photosynthetic microorganisms for enhanced bioremediation of microplastics:A comprehensive review

Mismanaged plastics,upon entering the environment,undergo degradation through physicochemical and/or biological processes.This process often results in the formation of microplastics(MPs),the most prevalent form of plastic debris(<1 mm).MPs pose severe threats to aquatic and terrestrial ecosystems,necessitating innovative strategies for effective remediation.Some photosynthetic microorganisms can degrade MPs but there lacks a comprehensive review.Here we examine the specific role of photoautotrophic microorganisms in water and soil environments for the biodegradation of plastics,focussing on their unique ability to grow persistently on diverse polymers under sunlight.Notably,these cells utilise light and CO_(2) to produce valuable compounds such as carbohydrates,lipids,and proteins,showcasing their multifaceted environmental benefits.We address key scientific questions surrounding the utilisation of photosynthetic microorganisms for MPs and nanoplastics(NPs)bioremediation,discussing potential engineering strategies for enhanced efficacy.Our review highlights the significance of alternative biomaterials and the exploration of strains expressing enzymes,such as polyethylene terephthalate(PET)hydrolases,in conjunction with microalgal and/or cyanobacterial metabolisms.Furthermore,we delve into the promising potential of photo-biocatalytic approaches,emphasising the coupling of plastic debris degradation with sunlight exposure.The integration of microalgal-bacterial consortia is explored for biotechnological applications against MPs and NPs pollution,showcasing the synergistic effects in wastewater treatment through the absorption of nitrogen,heavy metals,phosphorous,and carbon.In conclusion,this review provides a comprehensive overview of the current state of research on the use of photoautotrophic cells for plastic bioremediation.It underscores the need for continued investigation into the engineering of these microorganisms and the development of innovative approaches to tackle the global issue of plastic pollution in aquatic and terrestrial ecosystems.

Reservoir identification of marine facies carbonate shoals in the Middle Permian in the Sichuan Basin

Controlled by the base level change cycle,the carbonates exposed from the periodically shallowed water body at the top of the high-frequency sequence develops multiple sets of thin reservoirs.Such reservoir identification has always been tricky in the prediction of carbonate reservoirs.Based on the Middle Permian strata from the Sichuan Basin,this paper established a forecasting approach of high-frequency-sequence-controlled carbonate thin reservoir.The steps are as follows:(1)Combine the measured results of samples from the typical outcrops with changes of carbon and oxygen isotopes,thus to construct a division program for the 3rd-order sequence of the Middle Permian strata.(2)Compare the carbon and oxygen isotope changes and the global sea level change trend,determine the controlling factors of the 3rd-order sequences.(3)Carry out spectrum analysis based on the natural gamma energy spectrum logging(ln(Th/K))curves of Wells Long-17 and Anping-1 to establish a high-frequency sequence framework division program,and then apply the logging curve characteristics to correct the top interface positions of the high-frequency sequences,which is the potential location of carbonate reservoir.The research results suggest that the Middle Permian in the Sichuan Basin can be divided into three 3rd-order sequences,which are PSQ1,PSQ2 and PSQ3 from bottom to top.Among which,PSQ1 is mainly affected by global sea level(GSL)changes,and the changes originated from its tuning curve can be directly applied to the division of high-frequency sequences and reservoir prediction.PSQ2 and PSQ3 are jointly controlled by global sea level changes and regional tectonics.In cope with the influence of regional tectonics,the positions of the four-level sequence interface established according to the tuning curve need to be fully considered,and good results were achieved through systematical correction.This method can effectively reduce the risk of reservoir prediction caused by marine carbonate heterogeneity,and provide scientific foundation for the prediction of high-frequency cyclic reservoirs of platform facies and platform margin subfacies in other marine carbonate sedimentary basins.

Disruption of the autism-related gene Pak1 causes stereocilia disorganization,hair cell loss,and deafness in mice

Several clinical studies have reported that hearing loss is correlated with autism in children.However,little is known about the underlying mechanism between hearing loss and autism.p21-activated kinases(PAKs)are a family of serine/threonine kinases that can be activated by multiple signaling molecules,particularly the Rho family of small GTPases.Previous studies have shown that Pak1 mutations are associated with autism.In the present study,we take advantage of Pak1 knockout(Pak1a/a)mice to investigate the role of PAK1 in hearing function.We find that PAK1 is highly expressed in the postnatal mouse cochlea and that PAK1 deficiency leads to hair cell(HC)apoptosis and severe hearing loss.Further investigation indicates that PAK1 deficiency downregulates the phosphorylation of cofilin and ezrin-radixin-moesin and the expression of b II-spectrin,which further decreases the HC synapse density in the basal turn of cochlea and disorganized the HC stereocilia in all three turns of cochlea in Pak1à/àmice.Overall,our work demonstrates that the autism-related gene Pak1 plays a crucial role in hearing function.As the first candidate gene linking autism and hearing loss,Pak1 may serve as a potential target for the clinical diagnosis of autism-related hearing loss.

Sapphirine-Bearing Pelitic Granulite from Ailaoshan Orogen,West Yunnan,China: Metamorphic Conditions and Tectonic Setting

To reveal the petrological characteristics, metamorphic evolution histon and tectonic setting of the pelitic granulites from Ailaoshan Orogen, Uest Yunnan, China, a comprehensive study in mineral chemistry, petrogeochemistry and geochronology studies is presented in this paper. Two metamorphic stages of the granulites can be established:(1) the peak metamorphism recorded by the mineral assemblage of garnet, kyanite, K-feidspar and rutile, and the initial retrograde metamorphism shown by the mineral assemblage of garnet, sillimanite, sapphirine, spinel, K-feldspar, plagioclase and biotite;(2) the superim-posed metamorphism recorded by the mineral assemblage of biotite, muscovite, plagioclase, quartz and ilmenite. Zircon LA-ICP-MS U-Pb dating indicates that the protolith of the granulite was deposited after 337 Ma. The initial retrograde metamorphism occurred at P-T conditions of 8.6-12 kbar at 850-920℃ estimated by mineral assemblages, the low pressure limit of kyanite stability and GBPQ geothermobarometer in Indosinian (about 235 Ma), and the late superimposed metamorphism occurred at the P-T condition of 3.5-3.9 kbar at 572-576℃ estimated by GBPQ geothermobarometer since 33Ma. The first stage was related to the amalgamation of the South China and Indochina blocks during the Triassic, and the second stage was possibly related with the large scale sinistral slip-shearing since the Oligocene. It is inferred that the upper continental crust was suhducted/underthrusted to the lower continental crust (deeper than 30 km) and underwent granulite-facies metamorphism and then quickly exhumed to the middle-upper crust (10-12 km) and initial retrograde metamorphism occurred due to the collision of the Indochina and South China blocks during Indosinian, which was followed by superimposition of the second stage of metamorphism since the Oligocene.

Formation Mechanisms of Rudstones and Their Effects on Reservoir Quality in the Shulu Sag, Bohai Bay Basin, Eastern China

Based on observations made on cores and cuttings from several wells in the lowermost part of the third member of the Shahejie Formation, several rock types, specifically clast-supported rudstone, matrix-supported rudstone, mixed-source rudstone, calcisiltite/calcarenite, massive calci- lutite and laminated calcilutite, have been identified in the Shulu sag. According to the sedimentary structures and distribution characteristics of these rocks, the carbonate breccias fall into two cate- gories, based on their origins： one formed by fan-delta channel sedimentation, whereas the other formed by earthquake-induced slump fan deposition. Clast-supported rudstone and matrix- supported rudstone are the main lithologies deposited by braided rivers in the fan delta plain and front, of which the pore space is mainly dissolution pores within gravels and tectonic fissures. Clast- supported rudstone, matrix-supported rudstone and mixed-source rudstone are the main lithologies of the earthquake-induced slump fans. These carbonate breccias developed along with soft-sediment deformation structures, which are interpreted as seismites and are widely distributed in the sag, in which intercrystalline pores, intergranular pores and fissures created from diagenetic shrinkage are developed. The two kinds of rudstones have different reservoir characteristics and oil/gas testing re- suits. The rudstones generated in the fan delta have higher porosity and permeability, as well as bet- ter oil/gas testing results. Thus, they are key targets for petroleum exploration.

A novel strategy of fabricated flexible ITO electrode by liquid metal ultra-thin oxide film

Flexible transparent conductive films are gaining attention day by day over the last few years due to it is a key component of next generation flexible electronics and optoelectronic devices.Indium tin oxide(ITO)as one of the most widely used transparent conductive material is limited by the traditional deposition approach cannot be achieve ultra-thin,which results in its brittle nature.Herein,a novel strategy for fabricating highly transparent conductive films by liquid metal interface phase separation technique based on low-melting liquid metal of InxSn100-x alloy is reported,during the solid-to-liquid phase transition of alloy,the monolayer of surface oxide film segregated with the bulk phase and was printed on the flexible polyethylene-naphthalate(PEN)substrate under the van der Waals.This novel strategy can directly print the ultra-thin self-oxide with the structure of ITO on PEN substrate,with the resulting of transparency over 97.5%and resistivity as low as 0.21 kU cm,providing a new way of lowcost raw ITO material as well as the personalized preparation strategy.The desirable highly transparent conductive films are comparable to recently reported ITO film,together with advantages of pretty steady,make them attractive as various flexible transparent conductive electrodes,for example,an ultra-thin ITO film is developed for luminescent devices.