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Effects of freeze-thaw cycles on sandstone in sunny and shady slopes

Journal of Rock Mechanics and Geotechnical Engineering 2024年第7期16卷 2503-2515页

作者： Dian Xiao Xiaoyan Zhao Corrado Fidelibus roberto tom.s Qiu Lu Hongwei Liu Academy of Railway sciences Corporation Limited BeijingChina Faculty of Geosciences and Environmental Engineering Southwest Jiaotong UniversityChengduChina Department of Civil Engineering University of AlicanteAlicanteSpain Department of Innovation Engineering University of SalentoLecceItaly Department of Earth and Environmental sciences University of Milano BicoccaMilanItaly

A growing rock engineering activity in cold regions is facing the threat of freeze-thaw(FT)weathering,especially in high mountains where the sunny-shady slope effects strongly control the difference in weathering behavior of *** this paper,an investigation of the degradation of petrophysical characteristics of sandstone specimens subjected to FT cycle tests to simulate the sunny-shady slope effects is *** this aim,non-destructive and repeatable testing techniques including weight,ultrasonic waves,and nuclear magnetic resonance methods on standard specimens were *** the sunny slope specimens,accompanied by the enlargement of small pores,100 FT cycles caused a significant decrease in P-wave velocity with an average of 23%,but a consistent rise of 0.18%in mass loss,34%in porosity,67%in pore geometrical mean radius,and a remarkable 14.5-fold increase in ***,slight changes with some abnormal trends in physical parameters of the shady slope specimens were observed during FT cycling,which can be attributed to superficial granular disaggregation and pore throat *** shocks enhance rock weathering on sunny slopes during FT cycles,while FT weathering on shady slopes is restricted to the small pores and the superficial *** two factors are primarily responsible for the differences in FT weathering intensity between sunny and shady *** conclusions derived from the interpretation of the experimental results may provide theoretical guidance for the design of slope-failure prevention measures and the selection of transportation routes in cold mountainous regions.

关键词： sunny-shady slope Freeze and thaw Pore structure Tight rocks Talus slope Cold regions

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Assessment of compressive strength of jet grouting by machine learning

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第1期16卷 102-111页

作者： Esteban Diaz Edgar Leonardo salamanca-Medina roberto tom.s Departamento de Ingeniería Civil Escuela Politécnica SuperiorUniversidad de AlicanteP.O.Box 99E-03080AlicanteSpain

Jet grouting is one of the most popular soil improvement techniques,but its design usually involves great uncertainties that can lead to economic cost overruns in construction *** high dispersion in the properties of the improved material leads to designers assuming a conservative,arbitrary and unjustified strength,which is even sometimes subjected to the results of the test *** present paper presents an approach for prediction of the uniaxial compressive strength(UCs)of jet grouting columns based on the analysis of several machine learning algorithms on a database of 854 results mainly collected from different research *** selected machine learning model(extremely randomized trees)relates the soil type and various parameters of the technique to the value of the compressive *** the complex mechanism that surrounds the jet grouting process,evidenced by the high dispersion and low correlation of the variables studied,the trained model allows to optimally predict the values of compressive strength with a significant improvement with respect to the existing ***,this work proposes for the first time a reliable and easily applicable approach for estimation of the compressive strength of jet grouting columns.

关键词： Jet grouting Ground improvement Compressive strength Machine learning

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Current state-of-the-art review of footwear–ground friction

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Friction 2024年第10期12卷 2188-2204页

作者： David REBENDA tomáš sÁHA Footwear Research Centre University InstituteTomas Bata University in ZlinZlin 76001Czech Republic Faculty of Mechanical Engineering Brno University of TechnologyBron 61600Czech Republic

The most important role of footwear is to ensure safe,functional walking,and foot *** the proper functionality of not only the work shoes,the anti-slip behavior of the shoe under various conditions and environments plays an important role in the prevention of slips,trips,falls,and consequent *** article is intended to review the current understanding of the frictional mechanisms between shoe outsoles and various counterfaces that impact the evaluation of outsole *** research focuses on the mechanisms driving outsole friction on different ground surfaces or the definition and description of parameters that influence outsole ***,the review discusses the effect of various surface contaminants on footwear ***,challenges and outlooks in the field of footwear outsoles are briefly mentioned.

关键词： shoe outsole composite slipperiness coefficient of friction(COF) adhesion safe walk

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A Probabilistic Trust Model and Control Algorithm to Protect 6G Networks against Malicious Data Injection Attacks in Edge Computing Environments

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Computer Modeling in Engineering & sciences 2024年第10期141卷 631-654页

作者： Borja Bordel sánchez Ramón Alcarria tom.s Robles Department of Computer systems Universidad Politécnica de MadridMadrid28031Spain Department of Geospatial Engineering Universidad Politécnica de MadridMadrid28031Spain

Future 6G communications are envisioned to enable a large catalogue of pioneering *** will range from networked Cyber-Physical systems to edge computing devices,establishing real-time feedback control loops critical for managing Industry 5.0 deployments,digital agriculture systems,and essential *** provision of extensive machine-type communications through 6G will render many of these innovative systems autonomous and *** full automation will enhance industrial efficiency significantly,it concurrently introduces new cyber risks and *** particular,unattended systems are highly susceptible to trust issues:malicious nodes and false information can be easily introduced into control ***,Denialof-service attacks can be executed by inundating the network with valueless *** anomaly detection schemes require the entire transformation of the control software to integrate new steps and can only mitigate anomalies that conform to predefined mathematical *** based on an exhaustive data collection to detect anomalies are precise but extremely *** models,with their limited understanding of mobile networks,can achieve precision rates no higher than 75%.Therefore,more general and transversal protection mechanisms are needed to detect malicious behaviors *** paper introduces a probabilistic trust model and control algorithm designed to address this *** model determines the probability of any node to be *** channels are pruned for those nodes whose probability is below a given *** trust control algorithmcomprises three primary phases,which feed themodel with three different probabilities,which are weighted and ***,anomalous nodes are identified using Gaussian mixture models and clustering ***,traffic patterns are studied using digital Bessel functions and the functional scalar ***,the in

关键词： 6G networks noise injection attacks Gaussian mixture model Bessel function traffic filter Volterra filter

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Insights into reservoir-triggered landslides development and its influence factors in the Three Gorges Reservoir area， China

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Journal of Earth science 2024年

作者： shi-lin Luo Da Huang Jian-bing Peng Zhou-zhou Xie Zhi-yu Yang roberto tom.s College of Civil Engineering， Changsha University College of Civil Engineering and Geomatics， Chang'an University Hunan Provincial Key Laboratory for Big Data smart Application of Natural Disaster Risks survey of Highway Engineering school of Civil Engineering， Central south University Dpto.de Ingeniería Civil.Escuela Politécnica superior de Alicante.Universidad de Alicante.

More than 5000 landslides or potential landslides have been triggered in the Three Gorges Reservoir （TGR） area since the impoundment in 2003. Aimed at investigating the reservoir-induced landslides spatiotemporal and size distribution and its influence factors in the TGR by taking 790 landslides as statistical samples. The landslides exhibit significant regional and sub-regional differences in spatially， and numerous landslides occurred at the initial three impoundment stages and the corresponding following 2–3 cycles of reservoir operations， but the landslide frequency decreased dramatically after 2010 in temporally. The relationship between landslide development and topographical， geological as well as hydrological factors were analyzed qualitatively. The reservoir-induced landslides in TGR area exhibit self-organized criticality and the rollover is nearly 2.5×104m2， which could not attribute to the data missing but the coupled influences imposed by affecting factors. Both the double Pareto and inverse gamma functions are more suitable than the power-law function to present the landslide size characteristics. In term of the fitting precious， the adaptability of the inverse gamma function is better if the landslide inventories are limited. The research results provide foundation for the landslide susceptibility maps and hazard risk assessment.

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Porphyrinic Acceptors forFullerene-Free MolecularPhotovoltaics

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CCs Chemistry 2024年第2期6卷 276-296页

作者： Jorge Labella Juan Laforga-Martin tom.s Torres Department of Organic Chemistry Universidad Aut´onoma de Madrid28049 Madrid Institute for Advanced Research in Chemical sciences Universidad Aut´onoma de MadridMadrid IMDEA—Nanociencia 28049 Madrid

Over the past few years,the development of nonfullerene acceptors(NFAs)has become a prominent focus in both organic and perovskite solar cell(OsCs and PsCs,respectively)research *** this context,porphyrinoids,compounds structurally related to porphyrins,have emerged as promising solar cell *** contrast to the widely used fullerene acceptors,porphyrinoids exhibit strong,broad absorption properties across the UV–vis/NIR spectrum,which can be easily tuned through chemical ***,they can be prepared and derivatized using cost-effective and straightforward methodologies,allowing for convenient adjustments in thin-film morphology,processability,supramolecular organization,and energy ***,these compounds offer higher thermal and photochemical stability,resulting in longer device lifetimes compared to their fullerene-based *** this review,we outline the utilization of porphyrinoids as NFAs in OsCs and PsCs,discussing essential aspects such as design guidelines,molecular properties,and device *** goal is to inspire and further promote the development of n-type porphyrinoids,which have not yet fully unleashed their potential.

关键词： fullerene-free molecular photovoltaics nonfullerene acceptors porphyrinic acceptors n-type porphyrinoids organic and perovskite solar cells

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Real-world clinical efficacy of tofacitinib in moderate-to-severe ulcerative colitis

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World Journal of Gastroenterology 2024年第34期30卷 3929-3931页

作者： sara R Lopes Claudio Martins Madalena Teixeira David tom.s Department of Gastroenterology Unidade Local de Saúde da Arrábida-Hospital de São BernardoSetúbal 2910-446Portugal

Tofacitinib is an oral small-molecule Janus kinase(JAK)inhibitor that preferentially inhibits JAK1 and *** efficacy in inducing and maintaining remission in ulcerative colitis(UC)as well as its safety profile has been demonstrated in multicenter,randomized,double-blind,placebo-controlled ***,real-world studies evaluating the effectiveness and adverse effects of tofacitinib have been conducted,affirming its clinical efficacy in moderate-to-severe UC.

关键词： Ulcerative colitis Tofacitinib Real-world studies Inflammatory bowel disease Janus kinase inhibitor

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Endoscopic treatment of biliopancreatic pathology in patients with Whipple's pancreaticoduodenectomy surgical variants: Lessons learned from single-balloon enteroscopy-assisted ERCP

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Hepatobiliary & Pancreatic Diseases International 2024年第5期23卷 509-514页

作者： Rodrigo Garcés-Durán Laurent Monino Pierre H Deprez Hubert Piessevaux tom G Moreels Department of Gastroenterology and Hepatology Universitécatholique de LouvainCliniques Universitaires Saint-LucAvenue Hippocrates 101200 BrusselsBelgium

Background: Endoscopic treatment of biliopancreatic pathology is challenging due to surgically altered anatomy after Whipple's pancreaticoduodenectomy. This study aimed to evaluate the feasibility and safety of single-balloon enteroscopy-assisted endoscopic retrograde cholangiopancreatography(sBE-ERCP) to treat biliopancreatic pathology in patients with Whipple's pancreaticoduodenectomy surgical variants. Methods: We retrospectively analyzed 106 sBE-ERCP procedures in 46 patients with Whipple's variants. Technical and clinical success rates and adverse events were evaluated. Results: Biliary sBE-ERCP was performed in 34 patients and pancreatic sBE-ERCP in 17, including 5 with both indications. From a total of 106 sBE-ERCP procedures, 76 were biliary indication with technical success rate of 68/76(90%) procedures and clinical success rate of 30/34(88%) patients. Mild adverse event rate was 8/76(11%), without serious adverse events. From a total of 106 sBE-ERCP procedures, 30 were pancreatic indication with technical success rate of 24/30(80%) procedures( P = 0.194 vs. biliary sBEERCP) and clinical success rate of 11/17(65%) patients( P = 0.016 vs. biliary sBE-ERCP). Mild adverse event rate was 6/30(20%)( P = 0.194 vs. biliary sBE-ERCP), without serious adverse events. After sBE-ERCP failure, endoscopic ultrasound-guided drainage, percutaneous drainage and redo surgery were alternative therapeutic options. Conclusions: Biliopancreatic pathology after Whipple's pancreaticoduodenectomy variants can be treated using sBE-ERCP without serious adverse events. Technical and clinical success rates are high for biliary indications, whereas clinical success rate of pancreatic indications is significantly lower. sBE-ERCP can be considered as first-line treatment option in this patient group with surgically altered anatomy.

关键词： Enteroscopy Endoscopic retrograde cholangiopancreatography Pancreaticoduodenectomy surgically altered anatomy Whipple’s procedure

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Liquid superlubricity of lubricants containing hydroxyl groups and their aqueous solution under rolling/sliding conditions

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Friction 2024年第1期12卷 164-173页

作者： tomáš POLÁČEK Petr ŠPERKA Ivan KŘUPKA Faculty of Mechanical Engineering Brno University of TechnologyBrno 61669Czech Republic

Macroscale rolling/sliding conditions are in the superlubricity,a little-studied topic so *** purpose of this paper is to examine the formation of elastohydrodynamic lubrication(EHL)films by water-based lubricants(glycerol and polyethylene glycol(PEG)),providing superlubricous *** were carried out on an optical ball-on-disc tribometer under rolling/sliding *** film thickness was measured by the thin film colorimetric interferometry,and the viscosity of liquids was measured by rotational and high-pressure falling body *** results show that tribochemical reactions are not the mandatory reason for friction to reach the superlubricity level when using the water-based *** studied liquids themselves are almost *** the addition of water,the signs of shear thinning behavior disappear even *** conditions for this type of lubricant can be predicted using the known Hamrock–Dowson *** anomaly in the thickness of the lubricants was observed as an abrupt change at certain *** more PEG there is in the lubricant,the higher the thickness at the beginning of the jump.

关键词： macroscale superlubricity super low traction water-based lubricants elastohydrodynamic lubrication(EHL) film thickness

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Hydrochar and synthetic natural gas co-production for a full circular economy implementation via hydrothermal carbonization and methanation:An economic approach

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Journal of Environmental sciences 2024年第6期140卷 69-78页

作者： Judith González-Arias Guillermo Torres-sempere Miriam González-Castaño Francisco MBaena-Moreno tom.s RReina Inorganic Chemistry Department and Materials sciences Institute University of Seville-CSICSevilleSpain Materials sciences Institute(ICMsE) CSIC-University of SevilleSevilleSpain Department of Chemistry and Chemical Engineering Chalmers University of TechnologyGothenburgSE 41296Sweden

Herein we study the economic performance of hydrochar and synthetic natural gas coproduction from olive tree *** process entails a combination of hydrothermal carbonization and *** a previous work,we evidenced that standalone hydrochar production via HTC results ***,we propose a step forward on the process design by implementing a methanation,adding value to the gas effluent in an attempt to boost the overall process techno-economic *** different plant capacities were analyzed(312.5,625 and 1250 kg/hr).The baseline scenarios showed that,under the current circumstances,our circular economy strategy in *** analysis of the revenues shows that hydrochar selling price have a high impact on NPV and subsidies for renewable coal production could help to boost the profitability of the *** the contrary,the analysis for natural gas prices reveals that prices 8 times higher than the current ones in spain must be achieved to reach *** seems unlikely even under the presence of a strong subsidy *** costs analysis suggests that a remarkable electricity cost reduction or electricity consumption of the HTC stage could be a potential strategy to reach profitability ***,significant reduction of green hydrogen production costs is deemed instrumental to improve the economic performance of the *** results show the formidable techno-economic challenge that our society faces in the path towards circular economy societies.

关键词： Hydrothermal carbonization CO_(2)waste valorization Methanation Profitability analysis

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