Waste graphitization cathode carbon blocks are a type of hazardous solid waste generated during the aluminum electrolysis process,and their proper disposal is a key step in the resource utilization of discarded graphi...Waste graphitization cathode carbon blocks are a type of hazardous solid waste generated during the aluminum electrolysis process,and their proper disposal is a key step in the resource utilization of discarded graphite.This study utilizes the porous“defect advantage”of a cathode carbon block matrix to prepare silicon-doped and asphalt-coated detoxified and purified waste graphitization cathode carbon blocks for use as high-performance silicon/carbon composite anode materials.The results show that the uniformly silicondoped silicon/carbon composite material features a unique amorphous carbon-encapsulated“locked silicon”structure,which effectively addresses issues such as cathode volume expansion,excessive growth of the solid electrolyte interphase(SEI)film,and poor electrical contact between active materials.Consequently,electrochemical performance is enhanced.After assembly in a half-cell,the PSCC/10%Si@C(purified waste graphitization cathode carbon/10%Si@C)material exhibits optimal electrochemical stability,with an initial charging specific capacity of 514.5 mAh/g at 0.1 C(1 C=170 mA/g)and a capacity retention rate of 95.1%after 100 cycles.At a charge rate of 2.0 C,a specific capacity of 216.9 mAh/g is achieved.This technology provides a new pathway for the economical and high-value utilization of waste cathode carbon blocks and the development of low-cost,high-performance anode materials.展开更多
The identification and characterization of concealed in-situ rock blocks on high-steep slope exposures are critical in rock engineering,but remain challenging.This study employs advanced UAV-based photogrammetry to ca...The identification and characterization of concealed in-situ rock blocks on high-steep slope exposures are critical in rock engineering,but remain challenging.This study employs advanced UAV-based photogrammetry to capture high-resolution discontinuity data and develops a fully automated rock block extraction method consisting of three steps:(1)determination of free face and non-free fracture intersections,(2)surface search for rock blocks on free face.and(3)extraction and analysis of rock blocks.This approach simplifies the determination of discontinuity intersections while maintaining high accuracy.By incorporating all types of discontinuities contributing to rock block formation,the method enables precise in-situ rock block identification and extraction.Application to a rock slope in China,produced results consistent with the rock blocks observed in the 3D model,highlighting its accuracy and practical value.展开更多
Accurate identification and effective support of key blocks are crucial for ensuring the stability and safety of rock slopes.The number of structural planes and rock blocks were reduced in previous studies.This impair...Accurate identification and effective support of key blocks are crucial for ensuring the stability and safety of rock slopes.The number of structural planes and rock blocks were reduced in previous studies.This impairs the ability to characterize complex rock slopes accurately and inhibits the identification of key blocks.In this paper,a knowledge-data dually driven paradigm for accurate identification of key blocks in complex rock slopes is proposed.Our basic idea is to integrate key block theory into data-driven models based on finely characterizing structural features to identify key blocks in complex rock slopes accurately.The proposed novel paradigm consists of(1)representing rock slopes as graph-structured data based on complex systems theory,(2)identifying key nodes in the graph-structured data using graph deep learning,and(3)mapping the key nodes of graph-structured data to corresponding key blocks in the rock slope.Verification experiments and real-case applications are conducted by the proposed method.The verification results demonstrate excellent model performance,strong generalization capability,and effective classification results.Moreover,the real case application is conducted on the northern slope of the Yanqianshan Iron Mine.The results show that the proposed method can accurately identify key blocks in complex rock slopes,which can provide a decision-making basis and rational recommendations for effective support and instability prevention of rock slopes,thereby ensuring the stability of rock engineering and the safety of life and property.展开更多
Traffic-induced ground vibrations cause significant problems for residents and nearby structures.Reducing the effect of these vibrations on the neighboring environment is a key challenge,particularly in urban areas.Th...Traffic-induced ground vibrations cause significant problems for residents and nearby structures.Reducing the effect of these vibrations on the neighboring environment is a key challenge,particularly in urban areas.This study presents both numerical and experimental investigations of the performance of mass scatters for screening ground vibrations.A three-dimensional numerical model is validated and extended to conduct a comparative study on the efficiency of three geotechnical methods of isolation.These methods include trench barriers,waveimpeding blocks(WIBs),and mass scatters.The results showed that mass scatters represent an efficient way of scattering ground vibrations,and their efficiency is mainly related to the weights of mass scatters and their natural frequency,which control the dynamic soil response in the frequency domain.Rigid trench barriers are less effective than soft ones,and their efficiency is more pronounced regarding the WIB.Soft barriers with a depth of an order of half of the wavelength can decrease the vibration levels by up to 50%,which is comparable to the performance of enormous mass scatters.The dimensions of WIBs must be chosen according to the wavelength of incident waves and the cutoff frequency of the topsoil layer.Considering the significant wavelength of traffic-induced vibration,the use of trench barriers or WIBs becomes impractical and expensive;therefore,mass scatters appear to be an efficient and practical solution.展开更多
BACKGROUND Femur fractures are one of the most serious injuries that occur in the older population and are associated with severe pain and increased mortality.The primary objective of this study was to find if there w...BACKGROUND Femur fractures are one of the most serious injuries that occur in the older population and are associated with severe pain and increased mortality.The primary objective of this study was to find if there was a significant difference in pain scores in patients treated with femoral nerve blocks(FNB)compared with patients treated with the standard analgesia protocol.The secondary objective was to find if there was a significant difference in morbidity between the two groups.AIM To evaluate the effectiveness of ultrasound(US)-guided FNB in managing preoperative pain and reducing morbidity in patients with neck femur fractures compared to the standard analgesia protocol.The study seeks to determine whether FNB offers superior outcomes in terms of pain control,rehospitalization rates,and mortality.METHODS This retrospective cohort study included 1577 patients suffering from neck femur fractures.387 patients were treated with a FNB for pain management upon arrival at the emergency department,the rest were treated with standard analgesia.Pain was assessed from electronic medical records using the visual analogue scale(VAS)pre surgery,12-and 24-hour post-surgery.To determine morbidity and mortality during hospitalizations and 6 months after,it was collected from electronic medical records.RESULTS In a cohort of 1577 patients,those receiving US-guided FNB had significantly lower preoperative VAS pain scores(1.46±2.49 vs 1.82±2.59,P=0.001),reduced rehospitalization rates(0.99±1.96 vs 1.46±2.34,P<0.001),and lower mortality(16%vs 32%,P<0.001)compared to standard analgesia.CONCLUSION US guided FNB is more effective for pain management compared with standard analgesia.This method was also found to significantly reduce the risk of morbidity in those patients.展开更多
The purpose of this paper is to identify the processes with the highest contribution to potential environmental impacts in the life cycle of the masonry of concrete blocks by evaluating their main emissions contributi...The purpose of this paper is to identify the processes with the highest contribution to potential environmental impacts in the life cycle of the masonry of concrete blocks by evaluating their main emissions contributing to impact categories and identifying hotspots for environmental improvements.The research is based on the Life Cycle Assessment(LCA)study of non-load-bearing masonry of concrete blocks performed by the authors.The processes those have demonstrated higher contribution to environmental impacts were identified in the Life Cycle Impact Assessment(LCIA)phase and a detailed analysis was carried out on the main substances derived from these processes.The highest potential impacts in the life cycle of the concrete blocks masonry can be attributed mainly to emissions coming from the production of Portland cement,which explains the peak of impact potential on the blocks production stage,but also the significant impact potential in the use of the blocks for masonry construction,due to the use of cement mortar.The results of this LCA study are part of a major research on the comparative analysis of different typologies of non-load-bearing external walls,which aims to contribute to the creation of a life cycle database of major building systems,to be used by the environmental certification systems of buildings.展开更多
Uranium extraction from seawater(UES)is crucial for reducing nuclear fuel supply pressure and promoting the comprehensive utilization of marine resources.The successful implementations of UES engineering critically re...Uranium extraction from seawater(UES)is crucial for reducing nuclear fuel supply pressure and promoting the comprehensive utilization of marine resources.The successful implementations of UES engineering critically rely on the highly efficient sorbent materials with exceptional performance in binding uranyl ions.Herein,a universal and facile“organic ion building blocks self-assembly”strategy is established to realize a first class of carboxyl functionalized ionic single crystals,named BPTC-BPY-R(R=1–6,the R corresponds to alkyl chain length modifier,e.g.,R=1 corresponds to iodomethane derivatives,R=2 corresponds to bromoethane derivatives,etc.),derived from rationally designed viologen-derivatives with different alkyl chain lengths and polycarboxylic acid.This strategy effectively exploits the organic ion building block properties to achieve U(VI)adsorption based on the synergistic effects of anions(ligand interaction)and cations(electrostatic interaction).Notably,attributed to the special crystal stacking mode and higher specific surface area,the resulting BPTC-BPY-3 not only achieves ultrahigh selectivity for U(VI)adsorption with a partition coefficient of 3.998×10^(6) mL/g,but also possesses an ultrafast U(VI)adsorption kinetics and an uptake capacity of 686.8 mg/g within 2 min.More importantly,it realizes a U(VI)uptake capacity of 7.41 mg/g from natural seawater in 20 days.The designed material with ultra-selectivity,high capacity,ultrafast kinetics,and good recyclability exhibits a great promise for efficient U(VI)extraction from seawater.展开更多
Concrete pavement often experiences accelerated deterioration due to water and chemical ingress through micro-cracks and surface voids.Particularly,the ingress of aggressive agents into the concrete matrix results in ...Concrete pavement often experiences accelerated deterioration due to water and chemical ingress through micro-cracks and surface voids.Particularly,the ingress of aggressive agents into the concrete matrix results in irreversible changes and deterioration on its endurance.Numerous studies unveiled that hydrophobic surface protection could be an inexpensive and effective way of enhancing the durability of concrete.This research work aims to assess the feasibility of bio-cement posttreatment for facilitating hydrophobic surface protection,thus enhancing the performance and durability of concrete blocks.Enzyme induced carbonate precipitation(EICP)is one of the promising bio-cement methods.Concrete blocks casted in four different grades were subjected to EICP treatment with different treatment schemes and recipes of cementation media.The treated blocks were tested for water absorption,ultrasonic pulse velocity(UPV)measurements,unconfined compressive strength(UCS),thermal performance,and scanning electron microscopy(SEM).The results indicated that the concrete blocks subjected to EICP posttreatment showed over a 55%reduction in water absorption,a 15%higher UCS and a 6.7%higher UPV when compared with control blocks.The SEM analysis suggested that the EICP posttreatment could enhance the durability of concrete paving blocks by enabling a layer of calcite on the surface and by plugging the transport pore channels of the concrete.Although most of the posttreatment strategies investigated herein were found to be operative,a better response was seen in the posttreatment by spraying scheme with 0.5 mol/L cementation media(CM).With the successful demonstration,the EICP treatment prior to the use of concrete blocks can be recommended to the pavement construction industry.展开更多
The behavior of single-phase flow and conjugate heat transfer in micro-channel heat sinks(MCHS)subjected to auniform heat flux is investigated by means of numerical simulations.Various geometrical configurations areex...The behavior of single-phase flow and conjugate heat transfer in micro-channel heat sinks(MCHS)subjected to auniform heat flux is investigated by means of numerical simulations.Various geometrical configurations areexamined,particularly,the combinations of rectangular solid and perforated blocks,used to create a disturbancein the flow.The analysis focuses on several key aspects and related metrics,including the temperature distribution,the mean Fanning friction factor,the pressure drop,the Nusselt number,and the overall heat transfer coefficientacross a range of Reynolds numbers(80–870).It is shown that the introduction of such blocks significantlyenhances the heat transfer performances of the MCHS compared to the straight-through flow channel.Specifically,a case is found where the Nusselt number increases by 2.3 times relative to the reference case.The integrationof perforated blocks facilitates the generation of vorticity within the channel,promoting the mixing of coldand hot fluids.Notably,MCHS incorporating perforated rectangular blocks exhibit more pronounced heat transferbenefits at Reynolds numbers smaller than 400.展开更多
In this paper,we present a necessary and sufficient condition for hyponormal block Toeplitz operators T on the vector-valued weighted Bergman space with symbolsΦ(z)=G^(*)(z)+F(z),where F(z)=∑^(N)_(i)=1 A_(i)z^(i)and...In this paper,we present a necessary and sufficient condition for hyponormal block Toeplitz operators T on the vector-valued weighted Bergman space with symbolsΦ(z)=G^(*)(z)+F(z),where F(z)=∑^(N)_(i)=1 A_(i)z^(i)and G(z)=∑^(N)_(i)=1 A_(−i)z^(i),A_(i)ae culants.展开更多
Concrete blocks are widely used for wall construction in Thailand,and reliable Carbon Footprint of Product(CFP)data for these blocks is essential for accurately estimating the embodied carbon of buildings—a crucial c...Concrete blocks are widely used for wall construction in Thailand,and reliable Carbon Footprint of Product(CFP)data for these blocks is essential for accurately estimating the embodied carbon of buildings—a crucial consideration in sustainable building design.This research evaluates the CFP of concrete blocks produced by a Thai factory,using a functional unit of one ton.The assessment applies a“Cradle to Gate”approach,covering both raw material acquisition and product manufacturing stages.The study period spans one year,from January 1,2023,to December 31,2023.Results show that the CFP for the case study block is 88.508 kgCO₂eq/t,with the raw material acquisition stage responsible for 84.778 kgCO₂eq/t(95.79%of the CFP),and production stage emissions at 3.730 kgCO₂eq/t(4.21%of the CFP).A detailed analysis of greenhouse gas(GHG)emissions reveals several key findings:(1)Portland cement is the primary source,accounting for 80.69%of the CFP;(2)emissions from the transportation of crushed stone and coarse sand are notably high;(3)electricity usage contributes 2.558 kgCO₂eq/t;and(4)broken concrete blocks constitute 12.93%of the mixture volume.This study not only addresses a critical gap in the availability of CFP data for concrete blocks in sustainable building analysis in Thailand,but also identifies key areas where GHG emissions associated with concrete block manufacturing can be reduced.The insights provided here are valuable for concrete block manufacturers across Thailand,especially those with similar production processes,as they work toward lowering the CFP of their products.展开更多
Real-time monitoring of wellbore stability during drilling is crucial for the early detection of instability and timely interventions.The cause and type of wellbore instability can be identified by analyzing the dropp...Real-time monitoring of wellbore stability during drilling is crucial for the early detection of instability and timely interventions.The cause and type of wellbore instability can be identified by analyzing the dropped blocks brought to the surface by the drilling fluid,enabling preventive measures to be taken.In this study,an image capture system with fully automated sorting and 3D scanning was developed to obtain the complete 3D point cloud data of dropping blocks.The raw data obtained were preprocessed using methods such as format conversion,down sampling,coordinate transformation,statistical filtering,and clustering.Feature extraction algorithms,including the principal component analysis bounding box method,triangular meshing method,triaxial projection method,local curvature method,and model segmentation projection method,were employed,which resulted in the extraction of 32 feature parameters from the point cloud data.An optimal machine learning algorithm was developed by training it with 10 machine learning algorithms and the block data collected in the field.The XGBoost algorithm was then used to optimize the feature parameters and improve the classification model.An intelligent,fully automated feature parameter extraction and classification system was developed and applied to classify the types of falling blocks in 12 sets of drilling field and laboratory experiments and to identify the causes of wellbore instability.An average accuracy of 93.9%was achieved.This system can thus enable the timely diagnosis and implementation of preventive and control measures for wellbore instability in the field.展开更多
When patients initially present with atrial fibrillation along with an enlarged heart and heart failure, followed by atrioventricular block, it's essential to consider genetic factors.^([1])Genetic testing can off...When patients initially present with atrial fibrillation along with an enlarged heart and heart failure, followed by atrioventricular block, it's essential to consider genetic factors.^([1])Genetic testing can offer crucial diagnostic evidence, aiding in prognosis assessment and the adoption of appropriate treatment strategies.展开更多
Nanoporous polymers are extensively coated on various substrates to deliver optical,permselective,or other functions.However,it remains desired to fast produce uniform nanoporous polymer coatings on substrates with co...Nanoporous polymers are extensively coated on various substrates to deliver optical,permselective,or other functions.However,it remains desired to fast produce uniform nanoporous polymer coatings on substrates with complex surfaces.Herein,by manipulating the interactions between block copolymers and selective solvents,we prepare repairable nanoporous polymers on arbitrary substrates.This is realized by an extremely simple sequential coating process:sequential coating of block copolymers and their swelling agents on substrate surfaces.The swelling agents are comprised of two solvents that swell the constituent blocks of the copolymers to different degrees,rapidly producing polymer coatings with uniform,interconnected,sub-50 nm pores.This sequential coating process is able to conformally build nanoporous polymers on nonplanar substrates with large lateral sizes and complex surface features,and also to in situ repair defects arising during usages.We further demonstrate that the nanoporous coatings show excellent antireflective and membrane separation performances.This sequential coating process is dictated by polymer–solvent interactions,and is expected to find applications in diverse fields for its simplicity,adaptability,and the capability to produce well-defined nanoporosities.展开更多
The diagnostic efficacy of contemporary bioimaging technologies remains constrained by inherent limitations of conventional imaging agents,including suboptimal sensitivity,off-target biodistribution,and inherent cytot...The diagnostic efficacy of contemporary bioimaging technologies remains constrained by inherent limitations of conventional imaging agents,including suboptimal sensitivity,off-target biodistribution,and inherent cytotoxicity.These limitations have catalyzed the development of intelligent stimuli-responsive block copolymers-based bioimaging agents,which was engineered to dynamically respond to endogenous biochemical cues(e.g.,p H gradients,redox potential,enzyme activity,hypoxia environment) or exogenous physical triggers(e.g.,photoirradiation,thermal gradients,ultrasound(US)/magnetic stimuli).Through spatiotemporally controlled structural transformations,stimuli-responsive block copolymers enable precise contrast targeting,activatable signal amplification,and theranostic integration,thereby substantially enhancing signal-to-noise ratios of bioimaging and diagnostic specificity.Hence,this mini-review systematically examines molecular engineering principles for designing p H-,redox-,enzyme-,light-,thermo-,and US/magnetic-responsive polymers,with emphasis on structure-property relationships governing imaging performance modulation.Furthermore,we critically analyze emerging strategies for optical imaging,US synergies,and magnetic resonance imaging(MRI).Multimodal bioimaging has also been elaborated,which could overcome the inherent trade-offs between resolution,penetration depth,and functional specificity in single-modal approaches.By elucidating mechanistic insights and translational challenges,this mini-review aims to establish a design framework of stimuli-responsive block copolymersbased for high fidelity bioimaging agents and accelerate their clinical translation in precise diagnosis and therapy.展开更多
Switchable polymerization is emerging as a powerful tool to construct block copolymers directly from mixtures of monomers.However,current achievements typically iterate between two polymerization cycles to afford prod...Switchable polymerization is emerging as a powerful tool to construct block copolymers directly from mixtures of monomers.However,current achievements typically iterate between two polymerization cycles to afford products with fixed sequences and compositions.Herein,we report the triethylborane/1,8-diazabicyclo[5.4.0]undec-7-ene(Et_3B/DBU)pair-mediated four-component switchable polymerization of propylene oxide(PO),CO_(2),phthalic anhydride(PA),and racemic lactide(rac-LA),which enables the on-demand synthesis of four different block copolymers,i.e.,poly(propylene phthalate)-b-polylactide(PPE-b-PLA),PPE-b-PLA-b-poly(propylene carbonate)(PPC),PPE-b-PPC-b-PLA,and PPE-b-PPCb-poly(propylene oxide)(PPO),through rationally modulating the Lewis pair(LP)ratio.Core to this protocol is that increasing the loading of Et_(3)B accelerates the ring-opening of PO while impeding the reactivity of rac-LA,thus allowing for fine-tuning of the thermodynamic and kinetic of the switchable polymerization.Therefore,the four polymerization cycles involving PO/PA ring-opening copolymerization(ROCOP),PO/CO_(2) ROCOP,rac-LA ring-opening polymerization(ROP),and PO ROP can be connected and discriminated in precisely programmed manners.展开更多
This paper presents a novel artificial intelligence(AI)-assisted two-stage method for optimising rock slope stability by integrating advanced 3D modelling with rock support design,aiming at minimising risks,material u...This paper presents a novel artificial intelligence(AI)-assisted two-stage method for optimising rock slope stability by integrating advanced 3D modelling with rock support design,aiming at minimising risks,material usage,and costs.In the first stage,an extended key block analysis identifies key blocks and key block groups,accounting for progressive failure and force interactions.The second stage uses AI algorithms to optimise rockbolting design,balancing stability,cost,and material use.The most efficient algorithms include the multi-objective tree-structured Parzen estimator(MOTPE)and non-dominated sorting genetic algorithms(NSGA-II and NSGA-III).Applied to the Larvik rock slope,the optimised solution uses 18 pre-tensioned cablebolts,providing 13.2 MN of active force and achieving a factor of safety of 1.31 while reducing the average anchorage length by approximately 16%compared to traditional design.The AI-assisted approach also reduces computation time by over 90%compared to Quasi-Monte Carlo(QMC)methods,demonstrating its efficiency for small-scale civil engineering projects and large-scale mining operations.The developed tool is practical,compatible with Building Information Modelling(BIM),and ready for engineering implementation,supporting sustainable and cost-effective rock slope stabilisation.While the method is largely automated,professional judgement remains crucial for verifying ground conditions and selecting the final solution.Future work will focus on integrating data uncertainties,addressing complex block deformation mechanisms,refining optimisation objectives,and improving the performance of multi-objective optimisation for slope rockboling applications to further enhance the method's versatility.展开更多
Star-shaped six-arm polymers with hexaaza[2_(6)]orthoparacyclophane core and arms of block copolymers of poly-2-ethyl-5,6-dihydrooxazine with poly-2-isopropyl-5,6-dihydrooxazine were synthesized successfully using cat...Star-shaped six-arm polymers with hexaaza[2_(6)]orthoparacyclophane core and arms of block copolymers of poly-2-ethyl-5,6-dihydrooxazine with poly-2-isopropyl-5,6-dihydrooxazine were synthesized successfully using cationic ring-opening polymerization.The ratio of blocks,the order of their attachment to the core,and arm length were varied.Conformation of synthesized stars was determined by methods of molecular hydrodynamics and optics.It has been shown that star-shaped molecules were characterized by high intramolecular density,and the arm folding increased with their lengthening.The influence of the structure of block copolymers and their molar mass on the critical micelle concentration has been established.Complexes of synthesized star-shaped block copolymers with curcumin were obtained and the efficient binding of curcumin to polymer molecules was demonstrated.The behavior of the aqueous solutions of the prepared polymer stars and their complexes with curcumin was investigated by light scattering and turbidimetry methods.The influence of the structure and molar mass of star polymers on their thermoresponsiveness and the phase separation temperatures in aqueous solutions was analyzed.A slight increase in the phase separation temperature was found on passage from polymer solutions to solutions of polymer complexes with hydrophobic curcumin.展开更多
基金supported by the National Natural Science Foundation of China(No.52274346).
文摘Waste graphitization cathode carbon blocks are a type of hazardous solid waste generated during the aluminum electrolysis process,and their proper disposal is a key step in the resource utilization of discarded graphite.This study utilizes the porous“defect advantage”of a cathode carbon block matrix to prepare silicon-doped and asphalt-coated detoxified and purified waste graphitization cathode carbon blocks for use as high-performance silicon/carbon composite anode materials.The results show that the uniformly silicondoped silicon/carbon composite material features a unique amorphous carbon-encapsulated“locked silicon”structure,which effectively addresses issues such as cathode volume expansion,excessive growth of the solid electrolyte interphase(SEI)film,and poor electrical contact between active materials.Consequently,electrochemical performance is enhanced.After assembly in a half-cell,the PSCC/10%Si@C(purified waste graphitization cathode carbon/10%Si@C)material exhibits optimal electrochemical stability,with an initial charging specific capacity of 514.5 mAh/g at 0.1 C(1 C=170 mA/g)and a capacity retention rate of 95.1%after 100 cycles.At a charge rate of 2.0 C,a specific capacity of 216.9 mAh/g is achieved.This technology provides a new pathway for the economical and high-value utilization of waste cathode carbon blocks and the development of low-cost,high-performance anode materials.
基金supported by the National Key R&D Program of China(Grant No.2022YFC3080200)。
文摘The identification and characterization of concealed in-situ rock blocks on high-steep slope exposures are critical in rock engineering,but remain challenging.This study employs advanced UAV-based photogrammetry to capture high-resolution discontinuity data and develops a fully automated rock block extraction method consisting of three steps:(1)determination of free face and non-free fracture intersections,(2)surface search for rock blocks on free face.and(3)extraction and analysis of rock blocks.This approach simplifies the determination of discontinuity intersections while maintaining high accuracy.By incorporating all types of discontinuities contributing to rock block formation,the method enables precise in-situ rock block identification and extraction.Application to a rock slope in China,produced results consistent with the rock blocks observed in the 3D model,highlighting its accuracy and practical value.
基金supported by the National Natural Science Foundation of China(Grant Nos.42277161,42230709).
文摘Accurate identification and effective support of key blocks are crucial for ensuring the stability and safety of rock slopes.The number of structural planes and rock blocks were reduced in previous studies.This impairs the ability to characterize complex rock slopes accurately and inhibits the identification of key blocks.In this paper,a knowledge-data dually driven paradigm for accurate identification of key blocks in complex rock slopes is proposed.Our basic idea is to integrate key block theory into data-driven models based on finely characterizing structural features to identify key blocks in complex rock slopes accurately.The proposed novel paradigm consists of(1)representing rock slopes as graph-structured data based on complex systems theory,(2)identifying key nodes in the graph-structured data using graph deep learning,and(3)mapping the key nodes of graph-structured data to corresponding key blocks in the rock slope.Verification experiments and real-case applications are conducted by the proposed method.The verification results demonstrate excellent model performance,strong generalization capability,and effective classification results.Moreover,the real case application is conducted on the northern slope of the Yanqianshan Iron Mine.The results show that the proposed method can accurately identify key blocks in complex rock slopes,which can provide a decision-making basis and rational recommendations for effective support and instability prevention of rock slopes,thereby ensuring the stability of rock engineering and the safety of life and property.
文摘Traffic-induced ground vibrations cause significant problems for residents and nearby structures.Reducing the effect of these vibrations on the neighboring environment is a key challenge,particularly in urban areas.This study presents both numerical and experimental investigations of the performance of mass scatters for screening ground vibrations.A three-dimensional numerical model is validated and extended to conduct a comparative study on the efficiency of three geotechnical methods of isolation.These methods include trench barriers,waveimpeding blocks(WIBs),and mass scatters.The results showed that mass scatters represent an efficient way of scattering ground vibrations,and their efficiency is mainly related to the weights of mass scatters and their natural frequency,which control the dynamic soil response in the frequency domain.Rigid trench barriers are less effective than soft ones,and their efficiency is more pronounced regarding the WIB.Soft barriers with a depth of an order of half of the wavelength can decrease the vibration levels by up to 50%,which is comparable to the performance of enormous mass scatters.The dimensions of WIBs must be chosen according to the wavelength of incident waves and the cutoff frequency of the topsoil layer.Considering the significant wavelength of traffic-induced vibration,the use of trench barriers or WIBs becomes impractical and expensive;therefore,mass scatters appear to be an efficient and practical solution.
文摘BACKGROUND Femur fractures are one of the most serious injuries that occur in the older population and are associated with severe pain and increased mortality.The primary objective of this study was to find if there was a significant difference in pain scores in patients treated with femoral nerve blocks(FNB)compared with patients treated with the standard analgesia protocol.The secondary objective was to find if there was a significant difference in morbidity between the two groups.AIM To evaluate the effectiveness of ultrasound(US)-guided FNB in managing preoperative pain and reducing morbidity in patients with neck femur fractures compared to the standard analgesia protocol.The study seeks to determine whether FNB offers superior outcomes in terms of pain control,rehospitalization rates,and mortality.METHODS This retrospective cohort study included 1577 patients suffering from neck femur fractures.387 patients were treated with a FNB for pain management upon arrival at the emergency department,the rest were treated with standard analgesia.Pain was assessed from electronic medical records using the visual analogue scale(VAS)pre surgery,12-and 24-hour post-surgery.To determine morbidity and mortality during hospitalizations and 6 months after,it was collected from electronic medical records.RESULTS In a cohort of 1577 patients,those receiving US-guided FNB had significantly lower preoperative VAS pain scores(1.46±2.49 vs 1.82±2.59,P=0.001),reduced rehospitalization rates(0.99±1.96 vs 1.46±2.34,P<0.001),and lower mortality(16%vs 32%,P<0.001)compared to standard analgesia.CONCLUSION US guided FNB is more effective for pain management compared with standard analgesia.This method was also found to significantly reduce the risk of morbidity in those patients.
基金The authors would like to acknowledge CAPES (Higher Education Personnel Improvement Coordination) for the financial support given to this research.
文摘The purpose of this paper is to identify the processes with the highest contribution to potential environmental impacts in the life cycle of the masonry of concrete blocks by evaluating their main emissions contributing to impact categories and identifying hotspots for environmental improvements.The research is based on the Life Cycle Assessment(LCA)study of non-load-bearing masonry of concrete blocks performed by the authors.The processes those have demonstrated higher contribution to environmental impacts were identified in the Life Cycle Impact Assessment(LCIA)phase and a detailed analysis was carried out on the main substances derived from these processes.The highest potential impacts in the life cycle of the concrete blocks masonry can be attributed mainly to emissions coming from the production of Portland cement,which explains the peak of impact potential on the blocks production stage,but also the significant impact potential in the use of the blocks for masonry construction,due to the use of cement mortar.The results of this LCA study are part of a major research on the comparative analysis of different typologies of non-load-bearing external walls,which aims to contribute to the creation of a life cycle database of major building systems,to be used by the environmental certification systems of buildings.
基金supported by the National Natural Science Foundation of China(No.22374159)the Youth Innovation Promotion Association CAS(No.2021420).
文摘Uranium extraction from seawater(UES)is crucial for reducing nuclear fuel supply pressure and promoting the comprehensive utilization of marine resources.The successful implementations of UES engineering critically rely on the highly efficient sorbent materials with exceptional performance in binding uranyl ions.Herein,a universal and facile“organic ion building blocks self-assembly”strategy is established to realize a first class of carboxyl functionalized ionic single crystals,named BPTC-BPY-R(R=1–6,the R corresponds to alkyl chain length modifier,e.g.,R=1 corresponds to iodomethane derivatives,R=2 corresponds to bromoethane derivatives,etc.),derived from rationally designed viologen-derivatives with different alkyl chain lengths and polycarboxylic acid.This strategy effectively exploits the organic ion building block properties to achieve U(VI)adsorption based on the synergistic effects of anions(ligand interaction)and cations(electrostatic interaction).Notably,attributed to the special crystal stacking mode and higher specific surface area,the resulting BPTC-BPY-3 not only achieves ultrahigh selectivity for U(VI)adsorption with a partition coefficient of 3.998×10^(6) mL/g,but also possesses an ultrafast U(VI)adsorption kinetics and an uptake capacity of 686.8 mg/g within 2 min.More importantly,it realizes a U(VI)uptake capacity of 7.41 mg/g from natural seawater in 20 days.The designed material with ultra-selectivity,high capacity,ultrafast kinetics,and good recyclability exhibits a great promise for efficient U(VI)extraction from seawater.
基金supported by the following two grants:(i)Japan Society for the Promotion of Science(JSPS)KAKENHI Grant Number JP22H01581(i)National Research Counsil(NRC)of Sri Lanka Investigator Driven Grant Number 22-041.
文摘Concrete pavement often experiences accelerated deterioration due to water and chemical ingress through micro-cracks and surface voids.Particularly,the ingress of aggressive agents into the concrete matrix results in irreversible changes and deterioration on its endurance.Numerous studies unveiled that hydrophobic surface protection could be an inexpensive and effective way of enhancing the durability of concrete.This research work aims to assess the feasibility of bio-cement posttreatment for facilitating hydrophobic surface protection,thus enhancing the performance and durability of concrete blocks.Enzyme induced carbonate precipitation(EICP)is one of the promising bio-cement methods.Concrete blocks casted in four different grades were subjected to EICP treatment with different treatment schemes and recipes of cementation media.The treated blocks were tested for water absorption,ultrasonic pulse velocity(UPV)measurements,unconfined compressive strength(UCS),thermal performance,and scanning electron microscopy(SEM).The results indicated that the concrete blocks subjected to EICP posttreatment showed over a 55%reduction in water absorption,a 15%higher UCS and a 6.7%higher UPV when compared with control blocks.The SEM analysis suggested that the EICP posttreatment could enhance the durability of concrete paving blocks by enabling a layer of calcite on the surface and by plugging the transport pore channels of the concrete.Although most of the posttreatment strategies investigated herein were found to be operative,a better response was seen in the posttreatment by spraying scheme with 0.5 mol/L cementation media(CM).With the successful demonstration,the EICP treatment prior to the use of concrete blocks can be recommended to the pavement construction industry.
基金funded by the Project of the Hubei Provincial Department of Science and Technology(Grant No.2022CFB957)the Project of Hubei Engineering University of Teaching Research(Grant No.JY2024032)+1 种基金Ministry of Education University-Industry Cooperation Collaborative Education Project(Grant No.220903584161245)College Students’Innovation and Entrepreneurship Training Program(Grant Nos.DC2024031,DC2024032).
文摘The behavior of single-phase flow and conjugate heat transfer in micro-channel heat sinks(MCHS)subjected to auniform heat flux is investigated by means of numerical simulations.Various geometrical configurations areexamined,particularly,the combinations of rectangular solid and perforated blocks,used to create a disturbancein the flow.The analysis focuses on several key aspects and related metrics,including the temperature distribution,the mean Fanning friction factor,the pressure drop,the Nusselt number,and the overall heat transfer coefficientacross a range of Reynolds numbers(80–870).It is shown that the introduction of such blocks significantlyenhances the heat transfer performances of the MCHS compared to the straight-through flow channel.Specifically,a case is found where the Nusselt number increases by 2.3 times relative to the reference case.The integrationof perforated blocks facilitates the generation of vorticity within the channel,promoting the mixing of coldand hot fluids.Notably,MCHS incorporating perforated rectangular blocks exhibit more pronounced heat transferbenefits at Reynolds numbers smaller than 400.
文摘In this paper,we present a necessary and sufficient condition for hyponormal block Toeplitz operators T on the vector-valued weighted Bergman space with symbolsΦ(z)=G^(*)(z)+F(z),where F(z)=∑^(N)_(i)=1 A_(i)z^(i)and G(z)=∑^(N)_(i)=1 A_(−i)z^(i),A_(i)ae culants.
文摘Concrete blocks are widely used for wall construction in Thailand,and reliable Carbon Footprint of Product(CFP)data for these blocks is essential for accurately estimating the embodied carbon of buildings—a crucial consideration in sustainable building design.This research evaluates the CFP of concrete blocks produced by a Thai factory,using a functional unit of one ton.The assessment applies a“Cradle to Gate”approach,covering both raw material acquisition and product manufacturing stages.The study period spans one year,from January 1,2023,to December 31,2023.Results show that the CFP for the case study block is 88.508 kgCO₂eq/t,with the raw material acquisition stage responsible for 84.778 kgCO₂eq/t(95.79%of the CFP),and production stage emissions at 3.730 kgCO₂eq/t(4.21%of the CFP).A detailed analysis of greenhouse gas(GHG)emissions reveals several key findings:(1)Portland cement is the primary source,accounting for 80.69%of the CFP;(2)emissions from the transportation of crushed stone and coarse sand are notably high;(3)electricity usage contributes 2.558 kgCO₂eq/t;and(4)broken concrete blocks constitute 12.93%of the mixture volume.This study not only addresses a critical gap in the availability of CFP data for concrete blocks in sustainable building analysis in Thailand,but also identifies key areas where GHG emissions associated with concrete block manufacturing can be reduced.The insights provided here are valuable for concrete block manufacturers across Thailand,especially those with similar production processes,as they work toward lowering the CFP of their products.
基金supported by the Scientific research and technology development projects of CNPC“Research on Key Technologies and Equipment for Drilling and Completion of 10000-m Ultra-deep Oil and Gas Resources”(No.2022ZG06)“Development of a Complete Set of 70 MPa Intelligent Managed Pressure Drilling Equipment”(No.2024ZG35).
文摘Real-time monitoring of wellbore stability during drilling is crucial for the early detection of instability and timely interventions.The cause and type of wellbore instability can be identified by analyzing the dropped blocks brought to the surface by the drilling fluid,enabling preventive measures to be taken.In this study,an image capture system with fully automated sorting and 3D scanning was developed to obtain the complete 3D point cloud data of dropping blocks.The raw data obtained were preprocessed using methods such as format conversion,down sampling,coordinate transformation,statistical filtering,and clustering.Feature extraction algorithms,including the principal component analysis bounding box method,triangular meshing method,triaxial projection method,local curvature method,and model segmentation projection method,were employed,which resulted in the extraction of 32 feature parameters from the point cloud data.An optimal machine learning algorithm was developed by training it with 10 machine learning algorithms and the block data collected in the field.The XGBoost algorithm was then used to optimize the feature parameters and improve the classification model.An intelligent,fully automated feature parameter extraction and classification system was developed and applied to classify the types of falling blocks in 12 sets of drilling field and laboratory experiments and to identify the causes of wellbore instability.An average accuracy of 93.9%was achieved.This system can thus enable the timely diagnosis and implementation of preventive and control measures for wellbore instability in the field.
基金Military Healthcare Special Scientific Research Project(25BJZ31, awarded to SHI XM)。
文摘When patients initially present with atrial fibrillation along with an enlarged heart and heart failure, followed by atrioventricular block, it's essential to consider genetic factors.^([1])Genetic testing can offer crucial diagnostic evidence, aiding in prognosis assessment and the adoption of appropriate treatment strategies.
基金support from National Science Foundation of China(22438005)the Natural Science Foundation of Jiangsu Province(BE2022056-3)is gratefully acknowledged.
文摘Nanoporous polymers are extensively coated on various substrates to deliver optical,permselective,or other functions.However,it remains desired to fast produce uniform nanoporous polymer coatings on substrates with complex surfaces.Herein,by manipulating the interactions between block copolymers and selective solvents,we prepare repairable nanoporous polymers on arbitrary substrates.This is realized by an extremely simple sequential coating process:sequential coating of block copolymers and their swelling agents on substrate surfaces.The swelling agents are comprised of two solvents that swell the constituent blocks of the copolymers to different degrees,rapidly producing polymer coatings with uniform,interconnected,sub-50 nm pores.This sequential coating process is able to conformally build nanoporous polymers on nonplanar substrates with large lateral sizes and complex surface features,and also to in situ repair defects arising during usages.We further demonstrate that the nanoporous coatings show excellent antireflective and membrane separation performances.This sequential coating process is dictated by polymer–solvent interactions,and is expected to find applications in diverse fields for its simplicity,adaptability,and the capability to produce well-defined nanoporosities.
基金supported by the National Natural Science Foundation of China (Nos.22208218,22078196,and 22278268)the Natural Science Foundation of Shanghai (No.22ZR1460400)Collaborative Innovation Center of Fragrance Flavour and Cosmetics,and Collaborative Innovation Project of Shanghai Institute of Technology (No.XTCX2023-07)。
文摘The diagnostic efficacy of contemporary bioimaging technologies remains constrained by inherent limitations of conventional imaging agents,including suboptimal sensitivity,off-target biodistribution,and inherent cytotoxicity.These limitations have catalyzed the development of intelligent stimuli-responsive block copolymers-based bioimaging agents,which was engineered to dynamically respond to endogenous biochemical cues(e.g.,p H gradients,redox potential,enzyme activity,hypoxia environment) or exogenous physical triggers(e.g.,photoirradiation,thermal gradients,ultrasound(US)/magnetic stimuli).Through spatiotemporally controlled structural transformations,stimuli-responsive block copolymers enable precise contrast targeting,activatable signal amplification,and theranostic integration,thereby substantially enhancing signal-to-noise ratios of bioimaging and diagnostic specificity.Hence,this mini-review systematically examines molecular engineering principles for designing p H-,redox-,enzyme-,light-,thermo-,and US/magnetic-responsive polymers,with emphasis on structure-property relationships governing imaging performance modulation.Furthermore,we critically analyze emerging strategies for optical imaging,US synergies,and magnetic resonance imaging(MRI).Multimodal bioimaging has also been elaborated,which could overcome the inherent trade-offs between resolution,penetration depth,and functional specificity in single-modal approaches.By elucidating mechanistic insights and translational challenges,this mini-review aims to establish a design framework of stimuli-responsive block copolymersbased for high fidelity bioimaging agents and accelerate their clinical translation in precise diagnosis and therapy.
基金financially supported by National Key R&D Program Young Scientists Project(No.2023YFC3903100)the National Natural Science Foundation of China(No.22322503)analytical and testing assistance from the Analysis and Testing Center of HUST。
文摘Switchable polymerization is emerging as a powerful tool to construct block copolymers directly from mixtures of monomers.However,current achievements typically iterate between two polymerization cycles to afford products with fixed sequences and compositions.Herein,we report the triethylborane/1,8-diazabicyclo[5.4.0]undec-7-ene(Et_3B/DBU)pair-mediated four-component switchable polymerization of propylene oxide(PO),CO_(2),phthalic anhydride(PA),and racemic lactide(rac-LA),which enables the on-demand synthesis of four different block copolymers,i.e.,poly(propylene phthalate)-b-polylactide(PPE-b-PLA),PPE-b-PLA-b-poly(propylene carbonate)(PPC),PPE-b-PPC-b-PLA,and PPE-b-PPCb-poly(propylene oxide)(PPO),through rationally modulating the Lewis pair(LP)ratio.Core to this protocol is that increasing the loading of Et_(3)B accelerates the ring-opening of PO while impeding the reactivity of rac-LA,thus allowing for fine-tuning of the thermodynamic and kinetic of the switchable polymerization.Therefore,the four polymerization cycles involving PO/PA ring-opening copolymerization(ROCOP),PO/CO_(2) ROCOP,rac-LA ring-opening polymerization(ROP),and PO ROP can be connected and discriminated in precisely programmed manners.
基金support from Research Council of Norway via STIPINST PhD grant(Grant No.323307),Bever Control AS,and Bane NOR.
文摘This paper presents a novel artificial intelligence(AI)-assisted two-stage method for optimising rock slope stability by integrating advanced 3D modelling with rock support design,aiming at minimising risks,material usage,and costs.In the first stage,an extended key block analysis identifies key blocks and key block groups,accounting for progressive failure and force interactions.The second stage uses AI algorithms to optimise rockbolting design,balancing stability,cost,and material use.The most efficient algorithms include the multi-objective tree-structured Parzen estimator(MOTPE)and non-dominated sorting genetic algorithms(NSGA-II and NSGA-III).Applied to the Larvik rock slope,the optimised solution uses 18 pre-tensioned cablebolts,providing 13.2 MN of active force and achieving a factor of safety of 1.31 while reducing the average anchorage length by approximately 16%compared to traditional design.The AI-assisted approach also reduces computation time by over 90%compared to Quasi-Monte Carlo(QMC)methods,demonstrating its efficiency for small-scale civil engineering projects and large-scale mining operations.The developed tool is practical,compatible with Building Information Modelling(BIM),and ready for engineering implementation,supporting sustainable and cost-effective rock slope stabilisation.While the method is largely automated,professional judgement remains crucial for verifying ground conditions and selecting the final solution.Future work will focus on integrating data uncertainties,addressing complex block deformation mechanisms,refining optimisation objectives,and improving the performance of multi-objective optimisation for slope rockboling applications to further enhance the method's versatility.
基金financially supported by the Russian Science Foundation(No.23-13-00205)。
文摘Star-shaped six-arm polymers with hexaaza[2_(6)]orthoparacyclophane core and arms of block copolymers of poly-2-ethyl-5,6-dihydrooxazine with poly-2-isopropyl-5,6-dihydrooxazine were synthesized successfully using cationic ring-opening polymerization.The ratio of blocks,the order of their attachment to the core,and arm length were varied.Conformation of synthesized stars was determined by methods of molecular hydrodynamics and optics.It has been shown that star-shaped molecules were characterized by high intramolecular density,and the arm folding increased with their lengthening.The influence of the structure of block copolymers and their molar mass on the critical micelle concentration has been established.Complexes of synthesized star-shaped block copolymers with curcumin were obtained and the efficient binding of curcumin to polymer molecules was demonstrated.The behavior of the aqueous solutions of the prepared polymer stars and their complexes with curcumin was investigated by light scattering and turbidimetry methods.The influence of the structure and molar mass of star polymers on their thermoresponsiveness and the phase separation temperatures in aqueous solutions was analyzed.A slight increase in the phase separation temperature was found on passage from polymer solutions to solutions of polymer complexes with hydrophobic curcumin.
