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Laboratory study of fracture initiation and propagation in Barre granite under fluid pressure at stress state close to failure

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journal of Rock Mechanics and Geotechnical Engineering 2023年第3期15卷 538-550页

作者： Bing Q.Li Michela Casanova herbert H.Einstein Department of Civil and Environmental Engineering Massachusetts Institute of TechnologyCambridgeUSA Department of Civil and Environmental Engineering Western UniversityLondonCanada School of Architecture Civil and Environmental EngineeringÉcole Polytechnique Fédérale de LausanneLausanneSwitzerland

Hydraulic fracturing is frequently used to increase the permeability of rock formations in energy extraction scenarios such as unconventional oil and gas extraction and enhanced geothermal systems(EGSs).The present study addresses uncertainties in the hydraulic fracturing process pertaining to EGSs in crystalline rock such as ***,there is debate in the literature on the mechanisms(*** and/or shear)by which these fractures initiate,propagate,and *** present experiments on Barre granite with pre-cut flaws where the material is loaded to high far-field stresses close to shear failure,and then the fluid pressure in the flaws is increased to move the Mohr’s circle to the left and observe the initiation and propagation of fractures using high-speed imaging and acoustic emissions(AEs).We find that the hydraulic fractures initiate as tensile microcracks at the flaw tips,and then propagate as a combination of tensile and shear *** focal mechanisms also show elevated levels of tensional microfracturing near the flaw tips during pressurization and final *** then consider a numerical model of the experimental setup,where we find that fractures are indeed likely to initiate at flaw tips in tension even at relatively high far-field stresses of 40 MPa where shear failure is generally expected.

关键词： Acoustic emission(AE) Hydraulic fracturing Enhanced geothermal system(EGS) Microseismicity

Direct Evidence of Coal Swelling and Shrinkage with Injecting CO_(2) and N_(2) Using in-situ Synchrotron X-ray Microtomography

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Engineering 2022年第11期18卷 88-95页

作者： Guanglei Zhang P.G.Ranjith herbert E.Huppert Department of Earth Science and Engineering Imperial College LondonLondon SW72BPUK Deep Earth Energy Laboratory Department of Civil EngineeringMonash UniversityMelbourneVIC3800Australia Institute of Theoretical Geophysics King’s CollegeCambridge CB21STUK

Deep coal seams are one of the world’s most widespread deposits for carbon dioxide(C02)disposal and are generally located near large point sources of CO_(2)*** injection of CO_(2)into coal seams has great potential to sequester CO_(2)while simultaneously enhancing coalbed methane(CO_(2)-ECBM)*** tests of CO_(2)-ECBM have been conducted in coal seams worldwide with favorable early ***,one of the main technical barriers in coal seams needs to be resolved:Injecting CO_(2)reduces coal permeability and well ***,using in situ synchrotron X-ray microtomography,we provide the first observational evidence that injecting nitrogen(N_(2))can reverse much of this lost permeability by reopening fractures that have closed due to coal swelling induced by CO_(2)*** findings support the notion that injecting minimally treated flue gas-a mixture of mainly N_(2) and CO_(2)-is an attractive alternative for ECBM recovery instead of pure CO_(2)injection in deep coal ***,flue gas produced by power plants could be directly injected after particulate removal,thus avoiding high CO_(2)-separation ***,the presence of N_(2)makes it possible to maintain a sufficiently high level of coal *** results suggest that flue-gas ECBM for deep coal seams may provide a promising path toward net-zero emissions from coal mines.

关键词： CCS CO_(2)-ECBM Carbon neutrality X-ray imaging Coal permeability

Context dependent song-flight performance and timing in the Black-headed Bunting(Emberiza melanocephala)

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Avian Research 2022年第4期13卷 477-486页

作者： Sanja Barisic Davor Cikovic Vesna Tutis jelena Kralj herbert Hoi Institute of Ornithology Croatian Academy of Sciences and ArtsZagrebGunduliceva 2410000ZagrebCroatia Konrad Lorenz Institute of Ethology Department of Interdisciplinary Life SciencesUniversity of Veterinary Medicine ViennaSavoyenstraße 1A1160ViennaAustria

Many songbirds produce song-flights;however,the function,vocal and motor characteristics,as well as the diel and seasonal variation of song-flight in songbirds remain not well ***,we studied two types of song-flight in male Black-headed Buntings(Emberiza melanocephala),the Moth—a standard,i.e.,perch song produced during a horizontal flight,and the Towering—a specifically structured song produced during a complex ascending and descending *** perch song,used during Moth flight,has already been described,here we provide the first description and sonogram representation of the more elaborate and less stereotyped Towering *** males started to perform Moth song-flights as soon as they arrived at the breeding site,Towering did not start before the female *** usually delivered spontaneous Moth song-flights before chasing rivals or undertaking aerial fights,suggesting Moth is directed towards conspecific males and serves as a threat ***,playback of conspecific perch songs triggered males to approach the loudspeaker with Moth *** Towering started after females arrived at the breeding site,suggesting the Towering is directed towards conspecific *** detected a seasonal difference in the peak Towering rate between forenoon and afternoon,suggesting that Towerings performed at different times of the day have different *** Towerings were strongly positively related to the number of fertile females at the breeding site,while afternoon Towerings peaked very early in the breeding season and coincided with the number of females at the breeding site before the onset of *** results provide evidence that birds can direct different types of song-flight towards different receivers and suggest the possibility that time of the day determines the context of the display,namely to attract social mates or solicit *** work is needed to account for the effect of between male vari

关键词： Fertilisation probability Mate attraction Moth song-flight Towering song-flight

Behavioral parameters of six populations of/Wecavs phyllosomus longipennis(Heteroptera:Reduviidae)from areas with high and low prevalences of Trypanosoma cruzi human infection

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Insect Science 2021年第3期28卷 850-860页

作者： jose Alejandro Martinez-lbarra Benjamin Nogueda-Torres Oziel Dante Montanez-Valdez j.Guadalupe Michel-Parra Miguel Angel Ambriz-santos Laboratories de Entomologia Medica Centro Universitario del SurUniversidad de GuadalajaraCiudad GuzmanJaliscoMexico Cuerpo Academico de Cuencas Humedales y SustentabilidadDepartamento de Ciencias de la NaturalezaCentro Universitario del SurUniversidad de GuadalajaraCiudad GuzmanJaliscoMexico Becario de COFAA Escuela Nacional de Ciencias BioldgicasInstituto Politecnico NacionalCiudad de MexicoMexico

Three behaviors of epidemiological importance,namely feeding latency,feeding duration and defecation latency,for six populations of Meccus phyllosomus longipennis(Usinger)from areas of central,western and north-central Mexico with high(HP)and low(LP)prevalence of Trypanosoma cruzi(Chagas)human infection were evaluated in this *** median feeding latency(the time taken to begin feeding)was highly variable between ***-instar comparisons showed that at least 65%of the LP populations(N3 to adult)started to feed significantly(P<0.05)later than the HP population,with N1 showing no difference,and N2 from LP populations feeding sooner than those from HP *** six populations had similar median feeding durations within instars.A higher(P<0.05)percentage of the instars from HP populations defecated faster than the respective instars from the three LP *** 25%of the young nymphs(N1 to N3)and females in the HP populations defecated<2 min postfeeding,compared with 4%-6%of the young nymphs and 1.3%-3%of females in the LP ***,17.7%-38.8%of the older nymphs(N4 to N5)in the HP populations and 6.8%-13.4%in the LP populations defecated during or immediately after *** results indicate that the HP populations have a greater potential than the LP populations to transmit *** infections,which may underlie the differences in the prevalence of *** infection in some areas where M *** is currently distributed.

关键词： Chagas disease Meccus phyllosomus longipennis populations Mexico Tri-atominae Trypanosoma cruzi vectorial capacity

Loss of Hox5 function results in myofibroblast mislocalization and distal lung matrix defects during postnatal development

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Science China(Life Sciences) 2018年第9期61卷 1030-1038页

作者： Steven M.Hrycaj Leilani Marty-santos ANDrew j.Rasky Nicholas W.Lukacs Deneen M.Wellik Department of Internal Medicine Division of Molecular Medicine and Genetics University of Michigan Department of Pathology University of Michigan Department of Cell and Developmental Biology University of Michigan

Alveologenesis is the final stage of lung development and is responsible for the formation of the principle gas exchange units called alveoli. The lung mesenchyme, in particular the alveolar myofibroblasts, are drivers of alveolar development, however,few key regulators that govern the proper distribution and behavior of these cells in the distal lung during alveologenesis have been identified. While Hox5 triple mutants(Hox5 aabbcc) exhibit neonatal lethality, four-allele, compound mutant mice(Hox5 AabbCc) are born in Mendelian ratios and are phenotypically normal at birth. However, they exhibit defects in alveologenesis characterized by a BPD-like phenotype by early postnatal stages that becomes more pronounced at adult stages. Invasive pulmonary functional analyses demonstrate significant increases in total lung volume and compliance and a decrease in elastance in Hox5 compound mutants. SMA+ myofibroblasts in the distal lung are distributed abnormally during peak stages of alveologenesis and aggregate, resulting in the formation of a disrupted elastin network. Examination of other key components of the distal lung ECM, as well as other epithelial cells and lipofibroblasts reveal no differences in distribution. Collectively, these data indicate that Hox5 genes play a critical role in alveolar development by governing the proper cellular behavior of myofibroblasts during alveologenesis.

关键词： Hox5 alveologenesis alveolar myofibroblasts lung ECM postnatal lung development

Developments in diagnosis and treatment of paediatric septic arthritis

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World journal of Orthopedics 2022年第2期13卷 122-130页

作者： Cornelia M Donders Anne j Spaans herbert van Wering Christiaan jA van Bergen Department of Orthopaedic Surgery Meander Medical CentreAmersfoort 3813 TZNetherlands Department of Orthopaedic Surgery Sint MaartenskliniekNijmegen 6574 NANetherlands Department of Paediatrics Amphia HospitalBreda 4818 CKNetherlands Department of Orthopedic Surgery Amphia HospitalBreda 4818 CKNetherlands

Acute septic arthritis in children is an orthopaedic emergency.A delay in diagnosis and inappropriate treatment can result in devastating damage to the joint with lifelong disability as a *** clinical presentation can be a diagnostic challenge,especially in young children.A recent systematic review showed that joint tenderness and fever are important signals of septic *** is helpful in detecting the presence of a joint *** radiographs may show bone changes but magnetic resonance imaging is the most reliable imaging study for detecting concomitant *** diagnosis of acute septic arthritis is highly suggestive when pus is aspirated from the joint,in case of a positive culture or a positive gram stain of the joint fluid,or if there is a white blood-cell count in the joint fluid of more than 50000/*** aureus is the most commonly cultured *** systematic reviews have identified the most effective drainage techniques,including needle aspiration,arthroscopy and arthrotomy,depending on the affected *** the drainage procedure it is important to monitor the clinical and laboratory *** drainage procedures may be necessary in select cases.

关键词： Septic arthritis Paediatric Children Analysis Treatment Drainage

Intussusception in an infant with two non-diagnostic abdominal ultrasound studies

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World journal of Emergency Medicine 2019年第1期10卷 51-54页

作者： Vanessa santos james Espinosa Alan Lucerna Emergency Medicine Department Orange Regional Medical Center Emergency Medicine Department Rowan University School of Osteopathic Medicine

Dear editor,Intussusception is the invagination of one portion of the intestines into another, and is the most common form of intestinal obstruction in infants.^([1]) The vast majority of cases of intussusception are idiopathic, and are thought to be due to hyperplasia of the lymphoid tissue in the Peyer’s patches of the terminal ileum. The

关键词：小学英语课外阅读阅读材料

Incorporation of phenolic extracts from different by-products in yoghurts to create fortified and sustainable foods

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Food Bioscience 2023年第1期51卷 816-826页

作者： Sara M.Ferreira Lúcia santos LEPABE-Laboratory for Process Engineering EnvironmentBiotechnology and EnergyFaculty of EngineeringUniversity of PortoRua Dr.Roberto Frias4200-465PortoPortugal ALiCE-Associate Laboratory in Chemical Engineering Faculty of EngineeringUniversity of PortoRua Dr.Roberto Frias4200-465PortoPortugal

This work aimed to study and compare the effect of the incorporation of agro-industrial by-products(chestnut shell,grapeseed,and pomegranate peel)into yoghurts to fortify them while assessing their potential to replace synthetic *** each by-product,phenolic extracts were obtained and *** extracts demonstrated antioxidant and antibacterial properties,and the capacity to inhibitα-*** shell extract stood out regarding antioxidant capacity,displaying values of 1128 and 972 mgT_(rolox•gextract)^(-1),for the assays with DPPH and ABTS,*** yoghurts were produced(negative control,positive control with 0.1%of sorbic acid,two for each extract with 0.1%and 0.2%of extract,a mixture of extracts and a mixture of extracts with sorbic acid),and stored at 4℃.The incorporation of the extracts into the yoghurts maintained their physical-chemical properties and microbiological *** samples inhibited the growth of Escherichia coli and Staphylococcus *** analysis proved that higher concentrations of extract had similar results to synthetic *** results showed the viability to fortify yoghurts with the incorporation of by-product extracts,developing a value-added ***,revealed the possibility of these extracts replacing synthetic preservatives and antioxidants.

关键词： Antioxidants By-products Sustainability Circular economy Fortified foods Yoghurts Preservatives

Multiscale structural analysis inspired by exceptional load cases concerning the immersed tunnel of the Hong Kong-Zhuhai-Macao Bridge

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Underground Space 2018年第4期3卷 252-267页

作者： Hui Wang Eva Binder herbert Mang Yong Yuan Bernhard Pichler Institute for Mechanics of Materials and Structures TU Wien–Vienna University of TechnologyKarlsplatz 13/202A-1040 ViennaAustria College of Civil Engineering Tongji UniversityShanghaiChina

This paper contains an assessment of the added value of multiscale material models for concrete in the context of macroscopic struc-tural analysis of(steel-reinforced)concrete *** examples are *** are inspired by the possibility of car accidents inside the immersed tunnel of the Hong Kong-Zhuhai-Macao Bridge(HZMB).The first example deals with vehicles crashing into the tunnel *** high-dynamic strengthening effect of concrete is studied based on an engineering mechanics *** structural nature of the dynamic strength increase factor(DIF)is demonstrated by means of high-dynamic strength values measured on mortar cylinders of different ***,the evolution of the DIF as a function of hardening of concrete at material ages beyond 28 days is studied.A validated multiscale model for concrete renders a customized analysis for the specific concrete used for the aforementioned tunnel *** is found that the DIF decreases with progressive hardening of concrete at material ages beyond 28 *** second example is inspired by tunnel fires as may happen after car *** study refers to thermal stresses in steel-reinforced concrete beams sub-jected to sudden *** thermal expansion coefficient of the concrete of the tunnel is quantified by means of a multiscale *** is used as input for linear thermo-mechanical Finite-Element simulations of steel-reinforced concrete *** essential macroscopic simulation results are temperature distributions and associated stress *** are employed for top-down quantification of micro-scopic stress states inside the cement paste and the *** allows for quantifying two sources of microstructural stress fluctu-ations:(i)the macro-to-micro stress concentration and(ii)the mismatch of microscopic thermal expansion *** both examples,the multiscale models for concrete have increased the informative content of the structural simulations.

关键词： Concrete linings High-dynamic strength Thermal stresses