This paper introduces dynamic mode decomposition(DMD)as a novel approach to model the breakage kinetics of particulate systems.DMD provides a data-driven framework to identify a best-fit linear dynamics model from a s...This paper introduces dynamic mode decomposition(DMD)as a novel approach to model the breakage kinetics of particulate systems.DMD provides a data-driven framework to identify a best-fit linear dynamics model from a sequence of system measurement snapshots,bypassing the nontrivial task of determining appropriate mathemat-ical forms for the breakage kernel functions.A key innovation of our method is the instilling of physics-informed constraints into the DMD eigenmodes and eigenvalues,ensuring they adhere to the physical structure of particle breakage processes even under sparse measurement data.The integration of eigen-constraints is computationally aided by a zeroth-order global optimizer for solving the nonlinear,nonconvex optimization problem that elicits system dynamics from data.Our method is evaluated against the state-of-the-art optimized DMD algorithm using both generated data and real-world data of a batch grinding mill,showcasing over an order of magnitude lower prediction errors in data reconstruction and forecasting.展开更多
The increasing integration of small-scale structures in engineering,particularly in Micro-Electro-Mechanical Systems(MEMS),necessitates advanced modeling approaches to accurately capture their complex mechanical behav...The increasing integration of small-scale structures in engineering,particularly in Micro-Electro-Mechanical Systems(MEMS),necessitates advanced modeling approaches to accurately capture their complex mechanical behavior.Classical continuum theories are inadequate at micro-and nanoscales,particularly concerning size effects,singularities,and phenomena like strain softening or phase transitions.This limitation follows from their lack of intrinsic length scale parameters,crucial for representingmicrostructural features.Theoretical and experimental findings emphasize the critical role of these parameters on small scales.This review thoroughly examines various strain gradient elasticity(SGE)theories commonly employed in literature to capture these size-dependent effects on the elastic response.Given the complexity arising from numerous SGE frameworks available in the literature,including first-and second-order gradient theories,we conduct a comprehensive and comparative analysis of common SGE models.This analysis highlights their unique physical interpretations and compares their effectiveness in modeling the size-dependent behavior of low-dimensional structures.A brief discussion on estimating additional material constants,such as intrinsic length scales,is also included to improve the practical relevance of SGE.Following this theoretical treatment,the review covers analytical and numerical methods for solving the associated higher-order governing differential equations.Finally,we present a detailed overview of strain gradient applications in multiscale andmultiphysics response of solids.Interesting research on exploring the relevance of SGE for reduced-order modeling of complex macrostructures,a universal multiphysics coupling in low-dimensional structures without being restricted to limited material symmetries(as in the case of microstructures),is also presented here for interested readers.Finally,we briefly discuss alternative nonlocal elasticity approaches(integral and integro-differential)for incorporating size effects,and conclude with some potential areas for future research on strain gradients.This review aims to provide a clear understanding of strain gradient theories and their broad applicability beyond classical elasticity.展开更多
A hybrid Compressed Sensing and Primal-Dual Wavelet(CSP-PDW)technique is proposed for the compression and reconstruction of ECG signals.The compression and reconstruction algorithms are implemented using four key conc...A hybrid Compressed Sensing and Primal-Dual Wavelet(CSP-PDW)technique is proposed for the compression and reconstruction of ECG signals.The compression and reconstruction algorithms are implemented using four key concepts:Sparsifying Basis,Restricted Isometry Principle,Gaussian Random Matrix,and Convex Minimization.In addition to the conventional compression sensing reconstruction approach,wavelet-based processing is employed to enhance reconstruction efficiency.A mathematical model of the proposed algorithm is derived analytically to obtain the essential parameters of compression sensing,including the sparsifying basis,measurement matrix size,and number of iterations required for reconstructing the original signal and determining the type and level of wavelet processing.The low time complexity of the proposed algorithm makes it an ideal candidate for ECG monitoring systems in IoT-based e-healthcare applications.A feature extraction algorithm is also developed to show that the important ECG peaks remain unaltered after reconstruction.The clinical relevance of the reconstructed signal and the efficiency of the developed algorithm are evaluated using four validation parameters at three different compression ratios.展开更多
Background:Acute Myeloid Leukemia(AML)is a highly aggressive clonal hematological malignancy with limited treatment options.This study aimed to evaluate the therapeutic potential of nigericin,a polyether ionophore der...Background:Acute Myeloid Leukemia(AML)is a highly aggressive clonal hematological malignancy with limited treatment options.This study aimed to evaluate the therapeutic potential of nigericin,a polyether ionophore derived from Streptomyces DASNCL-29,as a mitochondrial-targeted agent for AML treatment.Methods:Nigericin was isolated from Streptomyces DASNCL-29 and characterized via chromatography and NMR.Its cytotoxicity was tested in MOLM13(sensitive and venetoclax-resistant)and HL60(sensitive and cytarabine-resistant)cells using the MTT assay.Mitochondrial dysfunction was assessed by measuring reactive oxygen species(ROS),mitochondrial membrane potential(Δψm),and mitochondrial mass.Apoptosis was evaluated with Annexin V/PI assays and immunoblotting,while proteomic analysis was conducted using Liquid Chromatography-Tandem Mass Spectrometry(LC-MS/MS)to identify differentially regulated proteins.Results:Nigericin demonstrated potent cytotoxicity with IC50 values of 57.02 nM in MOLM13-sensitive,35.29 nM in MOLM13-resistant,20.49 nM in HL60-sensitive,and 1.197 nM in HL60-cytarabine-resistant cells.Apoptosis was confirmed by Annexin V/PI staining and caspase-3/PARP cleavage,along with MCL-1 downregulation.Mitochondrial dysfunction was evident from increased ROS,reducedΔψm,and decreased mitochondrial mass.Proteomic profiling identified 264 dysregulated proteins,including a 3.8-fold upregulation of Succinate Dehydrogenase[Ubiquinone]Flavoprotein Subunit A(SDHA).Conclusion:Nigericin induces apoptosis in AML cells by disrupting mitochondrial function and enhancing oxidative stress.Its nanomolar potency highlights the need for further mechanistic studies and in vivo evaluations to explore its potential in AML treatment.展开更多
The waste management sector plays a vital role in environmental sustainability and public health.However,it faces significant challenges due to a multi-dimensional skills gap that hinders the effective management,proc...The waste management sector plays a vital role in environmental sustainability and public health.However,it faces significant challenges due to a multi-dimensional skills gap that hinders the effective management,processing and disposal of waste.Effective waste management requires increasing levels of technical expertise,analytical proficiency,behavioural skills and digital competence.However,one critical point of concern is the lack of requisite technical skills required for the optimal operation and maintenance of equipment and machinery used for waste management and disposal.Using desk research and focus group interviews of stakeholders in Nigeria and Ghana,we analyzed the skills gap in the sector in order to identify the skills that are currently short in supply in both countries.Our study revealed three broad skills need areas:(1)Skill requirements for youth employment in the waste management sector;(2)Machineries,technologies and tools used for waste management;and(3)Technical skills requirements for green waste management.The study concludes with a mapping of technologies and skills in the waste management sector while highlighting the impact of the existing skills deficit on the sector’s effectiveness and how it can be addressed through structured technical training programs for stakeholders in the sector.展开更多
BACKGROUND Spinal tuberculosis(TB),also known as Pott’s spine,remains a significant global health issue,particularly in regions with a high TB burden.The disease presents complex challenges in diagnosis,management,an...BACKGROUND Spinal tuberculosis(TB),also known as Pott’s spine,remains a significant global health issue,particularly in regions with a high TB burden.The disease presents complex challenges in diagnosis,management,and treatment,prompting a growing interest in research over recent years.The advancements in imaging,diagnostics,and treatment strategies have driven an increased focus on publishing clinical outcomes,review articles,and case series related to spinal TB(STB).AIM To perform a bibliometric analysis of STB research published over the last 5 years(2019-2023)to identify trends in publication volume,contributions by country,and the nature of the research being conducted.METHODS A comprehensive bibliometric analysis was conducted using the PubMed database,focusing on research articles published between 2019 and 2023.Keywords such as“spine tuberculosis,”“spinal TB,”“TB spine,”and“Pott’s spine”were utilized to capture relevant publications.Articles were analyzed based on the type of research(e.g.,case reports,review articles,cohort studies,randomized controlled trials[RCTs]),number of citations,and country of origin based on the corresponding author's details.Further subgroup analysis was performed according to the TB burden in various countries to assess research trends in high-burden regions.RESULTS A total of 528 articles met the inclusion criteria for this bibliometric analysis.The majority of articles were published between 2020 and 2023(440/528;83.3%),while the lowest number was published in 2019(88/528;16.7%).India led the global contributions with 25.8%of the total publications,followed by China(19.9%)and the United States(10.4%).Combined,African countries contributed 6.8%of the research on STB.Regarding the type of articles,case reports and case series dominated the literature(353/528;66.9%),followed by review articles(120/528;22.7%)and cohort studies(45/528;8.5%).Only 1.9%(10/528)of the studies were RCTs.Countries such as the United States,Germany,the United Kingdom,and Japan have pioneered the use of artificial intelligence(AI)in the diagnostic processes for STB,while India,China,South Africa,and other countries have been pivotal in conducting clinical trials and improving clinical management strategies.CONCLUSION This bibliometric analysis revealed a significant increase in STB research over the last 5 years,with India and China being the leading contributors.However,most publications are case reports or case series,with a limited number of RCTs.The results highlighted the need for more high-quality research,especially in terms of RCTs and innovations in diagnostic technologies.Additionally,the application of AI to STB diagnostics shows promise in developed countries,while high-burden countries are focusing on clinical trials and management strategies.展开更多
A total of 393 potholes(368 fluvial and 25 marine potholes)were studied at seven different sites in both the fluvial and marine environments.Diverse bedrock properties and large-scale delivery of tools and grinders re...A total of 393 potholes(368 fluvial and 25 marine potholes)were studied at seven different sites in both the fluvial and marine environments.Diverse bedrock properties and large-scale delivery of tools and grinders regulate the dynamic growth,truncation,and amalgamation of potholes.Therefore,the principal objectives of the study are(i)to examine the relationship between the growth of potholes and substrate lithological with structural characteristics(applying geospatial and Schmidt hammer for rock strength analysis)and(ii)to measure the morphology,and size of tools and grinders,processes of truncation and amalgamation in hydro-geomorphic environment using various indices and field techniques.The result showed that large potholes are stretched in the direction of lineament axes and roughly parallel to the river flow direction.Here,the steady growth of pothole depth-diameter is controlled by active bedrock structures,tools,or grinders,and monsoonal high-velocity bank full discharge.Consequently,the deepening and widening of potholes are relatively slow at Bindu,Deuli,and marine beach Neil Island due to fewer structures and little supply of tools or grinders.In small stretches,(Damodar,Subarnarekha,and Rarhu)canyons and gorge-like features(bedrock incision)are formed at Rajrappa,Bhakuyadi,and Guridih sites due to cyclic truncation and amalgamation.Truncation and amalgamation processes restrict the vertical depth threshold value of potholes within 3m,particularly at Rajrappa,Bhakuyadi,and Guridih sites.Scientific study of the pothole's dynamic growth is greatly necessary for the different environmental engineering and river hydraulic projects like excavation,dredging,and dam or barrage construction.Successively,it is essential to compute the cost of rock excavation or dredging,primarily for the mechanical strength of the bedrock river channel and its stability.展开更多
Cleanliness control of advanced steels is of vital importance for quality control of the products.In order to understand and control the inclusion removal during refining process in molten steel,its motion behaviors a...Cleanliness control of advanced steels is of vital importance for quality control of the products.In order to understand and control the inclusion removal during refining process in molten steel,its motion behaviors at the multiple steel/gas/slag interfaces have attracted the attention much of metallurgical community.The recent development of the agglomeration of non-metallic inclusions at the steel/Ar and steel/slag interfaces has been summarized,and both the experimental as well as theoretical works have been surveyed.In terms of in situ observation of high-temperature interfacial phenomena in the molten steel,researchers utilized high-temperature confocal laser scanning microscopy to observe the movement of more types of inclusions at the interface,i.e.,the investigated inclusion is no longer limited to Al_(2)O_(3)-based inclusions but moves forward to rare earth oxides,MgO-based oxides,etc.In terms of theoretical models,especially the model of inclusions at the steel/slag interface,the recent development has overcome the limitations of the assumptions of Kralchevsky-Paunov model and verified the possible errors caused by the model assumptions by combining the water model and the physical model.Last but not least,the future work in this topic has been suggested,which could be in combination of thermal physical properties of steels and slag,as well as utilize the artificial intelligence-based methodology to implement a comprehensive inclusion motion behaviors during a comprehensive metallurgical process.展开更多
High-temperature confocal laser scanning microscopy(HT-CLSM)is a robust characterization tool which can provide in situ real-time studies of materials processing.This facility has been applied in investigating interfa...High-temperature confocal laser scanning microscopy(HT-CLSM)is a robust characterization tool which can provide in situ real-time studies of materials processing.This facility has been applied in investigating interfacial phenomena in ironmaking and steelmaking as well as phase transformations during heat treatment of metallic materials.The pioneering work on the application of HTCLSM dates back to twenty-five years ago,to directly observe the crystallization of undercooled steel melt.展开更多
Pore pressure(PP)information plays an important role in analysing the geomechanical properties of the reservoir and hydrocarbon field development.PP prediction is an essential requirement to ensure safe drilling opera...Pore pressure(PP)information plays an important role in analysing the geomechanical properties of the reservoir and hydrocarbon field development.PP prediction is an essential requirement to ensure safe drilling operations and it is a fundamental input for well design,and mud weight estimation for wellbore stability.However,the pore pressure trend prediction in complex geological provinces is challenging particularly at oceanic slope setting,where sedimentation rate is relatively high and PP can be driven by various complex geo-processes.To overcome these difficulties,an advanced machine learning(ML)tool is implemented in combination with empirical methods.The empirical method for PP prediction is comprised of data pre-processing and model establishment stage.Eaton's method and Porosity method have been used for PP calculation of the well U1517A located at Tuaheni Landslide Complex of Hikurangi Subduction zone of IODP expedition 372.Gamma-ray,sonic travel time,bulk density and sonic derived porosity are extracted from well log data for the theoretical framework construction.The normal compaction trend(NCT)curve analysis is used to check the optimum fitting of the low permeable zone data.The statistical analysis is done using the histogram analysis and Pearson correlation coefficient matrix with PP data series to identify potential input combinations for ML-based predictive model development.The dataset is prepared and divided into two parts:Training and Testing.The PP data and well log of borehole U1517A is pre-processed to scale in between[-1,+1]to fit into the input range of the non-linear activation/transfer function of the decision tree regression model.The Decision Tree Regression(DTR)algorithm is built and compared to the model performance to predict the PP and identify the overpressure zone in Hikurangi Tuaheni Zone of IODP Expedition 372.展开更多
The breakage of brittle particulate materials into smaller particles under compressive or impact loads can be modelled as an instantiation of the population balance integro-differential equation.In this paper,the emer...The breakage of brittle particulate materials into smaller particles under compressive or impact loads can be modelled as an instantiation of the population balance integro-differential equation.In this paper,the emerging computational science paradigm of physics-informed neural networks is studied for the first time for solving both linear and nonlinear variants of the governing dynamics.Unlike conventional methods,the proposed neural network provides rapid simulations of arbitrarily high resolution in particle size,predicting values on arbitrarily fine grids without the need for model retraining.The network is assigned a simple multi-head architecture tailored to uphold monotonicity of the modelled cumulative distribution function over particle sizes.The method is theoretically analyzed and validated against analytical results before being applied to real-world data of a batch grinding mill.The agreement between laboratory data and numerical simulation encourages the use of physics-informed neural nets for optimal planning and control of industrial comminution processes.展开更多
Nafion as a universal polymer ionomer was widely applied for nanocatalysts electrode preparation.However,the effect of Nafion on electrocatalytic performance was often overlooked,especially for CO_(2)electrolysis.Here...Nafion as a universal polymer ionomer was widely applied for nanocatalysts electrode preparation.However,the effect of Nafion on electrocatalytic performance was often overlooked,especially for CO_(2)electrolysis.Herein,the key roles of Nafion for CO_(2)RR were systematically studied on Cu nanoparticles(NPs)electrocatalyst.We found that Nafion modifier not only inhibit hydrogen evolution reaction(HER)by decreasing the accessibility of H_(2)O from electrolyte to Cu NPs,and increase the CO_(2)concentration at electrocatalyst interface for enhancing the CO_(2)mass transfer process,but also activate CO_(2)molecule by Lewis acid-base interaction between Nafion and CO_(2)to accelerate the formation of^(*)CO,which favor of C–C coupling for boosting C_(2)product generation.Owing to these features,the HER selectivity was suppressed from 40.6%to 16.8%on optimal Cu@Nafion electrode at-1.2 V versus reversible hydrogen electrode(RHE),and as high as 73.5%faradaic efficiencies(FEs)of C_(2)products were achieved at the same applied potential,which was 2.6 times higher than that on bare Cu electrode(~28.3%).In addition,Nafion also contributed to the long-term stability by hinder Cu NPs morphology reconstruction.Thus,this work provides insights into the impact of Nafion on electrocatalytic CO_(2)RR performance.展开更多
The monomolecular surface layer of acceptor doped CeO_(2) may become neutral and metallic or charged and semiconducting.This is revealed in the theoretical analysis of the oxygen pressure dependence of the surface def...The monomolecular surface layer of acceptor doped CeO_(2) may become neutral and metallic or charged and semiconducting.This is revealed in the theoretical analysis of the oxygen pressure dependence of the surface defects concentration in acceptor doped ceria with two different dopant types and operated under different oxygen pressures.Recently published experimental data for highly reduced Sm0.2Ce0.8O1.9-x(SDC)containing a fixed valence dopant Sm3+are very different from those published for Pr0.1Ce0.9O_(2)-x(PCO) with the variable valence dopant Pr4+/Pr3+being reduced under milder conditions.The theoretical analysis of these experimental results fits very well the experimental results of SDC and PCO.It leads to the following predictions:the highly reduced surface of SDC is metallic and neutral,the metallic surface electron density of state is gs=0.9×10^(38)J-1·m^(-2)(1.4×1015eV^(-1)·cm^(-2)),the electron effective mass is meff,s=3.3me,and the phase diagram of the reduced surface has theα(fcc)structure as in the bulk.In PCO a double layer is predicted to be formed between the surface and the bulk with the surface being negatively charged and semiconducting.The surface of PCO maintains high Pr^(3+) defect concentration as well as relative high oxygen vacancy concentration at oxygen pressures higher than in the bulk.The reasons for the difference between a metallic and semiconducting surface layer of acceptor doped CeO_(2) are reviewed,as well as the key theoretical considerations applied in coping with this problem.For that we make use of the experimental data and theoretical analysis available for acceptor doped ceria.展开更多
In this technologically advancing world,the demand for more energy,oil and gas production is rapidly escalating.To accomplish this,people have inclined more towards completely floating offshore structures,deployed in ...In this technologically advancing world,the demand for more energy,oil and gas production is rapidly escalating.To accomplish this,people have inclined more towards completely floating offshore structures,deployed in deep waters.A semi-submersible is selected in the present study,due to its better response characteristics and stability under harsh environmental conditions.The semi-submersible is position restrain with spread mooring lines incorporated with submerged buoy at different locations has been studied.A detailed numerical analysis is carried out using Ansys Aqwa for dynamic response analysis of semi-submersible under the combination of wind,wave,and current forces for 0°,45°,and 90°directions.It was observed that damping ratios and natural periods had been affected based on the position and number of submerged buoys in the mooring system.Also,reduction in mooring force after incorporating buoy in the mooring lines was observed.Subsequently,a Matlab code based on the S-N curve approach was generated and employed to investigate the fatigue damage of mooring lines under dynamic variation of mooring forces.When pegged with submerged buoys,fatigue life of mooring lines is increased under intact and postulated damaged mooring conditions.Moreover,coupling of motion responses of semi-submersible is observed,and unbounded response is not seen in any degrees-offreedom,even during damaged condition of mooring lines.展开更多
The present study reported the influence of heavy rare-earth elements(Gd and/or Dy)on Sm-Co-based melt-spun ribbons.Microstructure and magnetic properties of Sm-Co-based(Sm_(1-x)RE_(x)Co_(5))ternary and quaternary sys...The present study reported the influence of heavy rare-earth elements(Gd and/or Dy)on Sm-Co-based melt-spun ribbons.Microstructure and magnetic properties of Sm-Co-based(Sm_(1-x)RE_(x)Co_(5))ternary and quaternary systems were investigated.The X-ray diffraction,Auger spectroscopy,scanning electron microscopy(SEM)and transmission electron microscopy(TEM)analyses reveal the presence of the 1:5H and 2:17R phases in the as-spun ribbons.A high-temperature magnetic measurement reports a Curie temperature(Tc)at~825 and~869 K in Sm0.6Gd0.4Co5(ribbon A)and Sm_(0.6)Gd_(0.3)Dy_(0.1)Co_(5)(ribbon B),respectively.A low-temperature magnetic measurement on Sm0.6Gd0.3Dy0.1Co5 ribbons exhibits a type-2 SR(spin reorientation)behaviour at~72 K,which arises due to the presence of the DyCo5 phase.Room temperature magnetic measurements reveal that overall magnetic measurement(OMP)is about 24 and 29.9 for ribbons A and B,respectively.Consequently,the comparative investigations profess that ribbon B shows better magnetic performance due to Dy addition with reduced grain size.This observation indicates that the Gd and Dy substituted Sm-Co magnet can be a potential magnet for high-temperature applications.展开更多
Traditional global sensitivity analysis(GSA)neglects the epistemic uncertainties associated with the probabilistic characteristics(i.e.type of distribution type and its parameters)of input rock properties emanating du...Traditional global sensitivity analysis(GSA)neglects the epistemic uncertainties associated with the probabilistic characteristics(i.e.type of distribution type and its parameters)of input rock properties emanating due to the small size of datasets while mapping the relative importance of properties to the model response.This paper proposes an augmented Bayesian multi-model inference(BMMI)coupled with GSA methodology(BMMI-GSA)to address this issue by estimating the imprecision in the momentindependent sensitivity indices of rock structures arising from the small size of input data.The methodology employs BMMI to quantify the epistemic uncertainties associated with model type and parameters of input properties.The estimated uncertainties are propagated in estimating imprecision in moment-independent Borgonovo’s indices by employing a reweighting approach on candidate probabilistic models.The proposed methodology is showcased for a rock slope prone to stress-controlled failure in the Himalayan region of India.The proposed methodology was superior to the conventional GSA(neglects all epistemic uncertainties)and Bayesian coupled GSA(B-GSA)(neglects model uncertainty)due to its capability to incorporate the uncertainties in both model type and parameters of properties.Imprecise Borgonovo’s indices estimated via proposed methodology provide the confidence intervals of the sensitivity indices instead of their fixed-point estimates,which makes the user more informed in the data collection efforts.Analyses performed with the varying sample sizes suggested that the uncertainties in sensitivity indices reduce significantly with the increasing sample sizes.The accurate importance ranking of properties was only possible via samples of large sizes.Further,the impact of the prior knowledge in terms of prior ranges and distributions was significant;hence,any related assumption should be made carefully.展开更多
In seismic exploration,it is a critical task to image and interpret different seismic signatures over complex geology due to strong lateral velocity contrast,steep reflectors,overburden strata and dipping flanks.To un...In seismic exploration,it is a critical task to image and interpret different seismic signatures over complex geology due to strong lateral velocity contrast,steep reflectors,overburden strata and dipping flanks.To understand the behavior of these seismic signatures,nowadays Reverse Time Migration(RTM)technique is used extensively by the oil&gas industries.During the extrapolation phase of RTM,the source wavefield needs to be saved,which needs high storage memory and large computing time.These two are the main obstacles of RTM for production use.In order to overcome these disadvantages,in this study,a second-generation improved RTM technique is proposed.In this improved form,a shift operator is introduced at the time of imaging condition of RTM algorithm which is performed automatically both in space and time domain.This effort is made to produce a better-quality image by minimizing the computational time as well as numerical artefacts.The proposed method is applied over various benchmark models and validated by implementing over one field data set from the Jaisalmer Basin,India.From the analysis,it is observed that the method consumes a minimum of 45%less storage space and reduce the execution time by 20%,as compared to conventional RTM.The proposed RTM is found to work efficiently in comparison to the conventional RTM both in terms of imaging quality and minimization of numerical artefacts for all the benchmark models as well as field data.展开更多
One of the most dangerous safety hazard in underground coal mines is roof falls during retreat mining.Roof falls may cause life-threatening and non-fatal injuries to miners and impede mining and transportation operati...One of the most dangerous safety hazard in underground coal mines is roof falls during retreat mining.Roof falls may cause life-threatening and non-fatal injuries to miners and impede mining and transportation operations.As a result,a reliable roof fall prediction model is essential to tackle such challenges.Different parameters that substantially impact roof falls are ill-defined and intangible,making this an uncertain and challenging research issue.The National Institute for Occupational Safety and Health assembled a national database of roof performance from 37 coal mines to explore the factors contributing to roof falls.Data acquired for 37 mines is limited due to several restrictions,which increased the likelihood of incompleteness.Fuzzy logic is a technique for coping with ambiguity,incompleteness,and uncertainty.Therefore,In this paper,the fuzzy inference method is presented,which employs a genetic algorithm to create fuzzy rules based on 109 records of roof fall data and pattern search to refine the membership functions of parameters.The performance of the deployed model is evaluated using statistical measures such as the Root-Mean-Square Error,Mean-Absolute-Error,and coefficient of determination(R_(2)).Based on these criteria,the suggested model outperforms the existing models to precisely predict roof fall rates using fewer fuzzy rules.展开更多
The present research work attempted to delineate and characterize the reservoir facies from the Dawson Canyon Formation in the Penobscot field,Scotian Basin.An integrated study of instantaneous frequency,P-impedance,v...The present research work attempted to delineate and characterize the reservoir facies from the Dawson Canyon Formation in the Penobscot field,Scotian Basin.An integrated study of instantaneous frequency,P-impedance,volume of clay and neutron-porosity attributes,and structural framework was done to unravel the Late Cretaceous depositional system and reservoir facies distribution patterns within the study area.Fault strikes were found in the EW and NEE-SWW directions indicating the dominant course of tectonic activities during the Late Cretaceous period in the region.P-impedance was estimated using model-based seismic inversion.Petrophysical properties such as the neutron porosity(NPHI)and volume of clay(VCL)were estimated using the multilayer perceptron neural network with high accuracy.Comparatively,a combination of low instantaneous frequency(15-30 Hz),moderate to high impedance(7000-9500 gm/cc*m/s),low neutron porosity(27%-40%)and low volume of clay(40%-60%),suggests fair-to-good sandstone development in the Dawson Canyon Formation.After calibration with the welllog data,it is found that further lowering in these attribute responses signifies the clean sandstone facies possibly containing hydrocarbons.The present study suggests that the shale lithofacies dominates the Late Cretaceous deposition(Dawson Canyon Formation)in the Penobscot field,Scotian Basin.Major faults and overlying shale facies provide structural and stratigraphic seals and act as a suitable hydrocarbon entrapment mechanism in the Dawson Canyon Formation's reservoirs.The present research advocates the integrated analysis of multi-attributes estimated using different methods to minimize the risk involved in hydrocarbon exploration.展开更多
Salter's duck,an asymmetrical wave energy converter(WEC)device,showed high efficiency in extracting energy from 2D regular waves in the past;yet,challenges remain for fluctuating wave conditions.These can potentia...Salter's duck,an asymmetrical wave energy converter(WEC)device,showed high efficiency in extracting energy from 2D regular waves in the past;yet,challenges remain for fluctuating wave conditions.These can potentially be addressed by adopting a negative stiffness mechanism(NSM)in WEC devices to enhance system efficiency,even in highly nonlinear and steep 3D waves.A weakly nonlinear model was developed which incorporated a nonlinear restoring moment and NSM into the linear formulations and was applied to an asymmetric WEC using a time domain potential flow model.The model was initially validated by comparing it with published experimental and numerical computational fluid dynamics results.The current results were in good agreement with the published results.It was found that the energy extraction increased in the range of 6%to 17%during the evaluation of the effectiveness of the NSM in regular waves.Under irregular wave conditions,specifically at the design wave conditions for the selected test site,the energy extraction increased by 2.4%,with annual energy production increments of approximately 0.8MWh.The findings highlight the potential of NSM in enhancing the performance of asymmetric WEC devices,indicating more efficient energy extraction under various wave conditions.展开更多
基金supported by the Ramanujan Fellowship from the Science and Engineering Research Board,Government of India(Grant No.RJF/2022/000115).
文摘This paper introduces dynamic mode decomposition(DMD)as a novel approach to model the breakage kinetics of particulate systems.DMD provides a data-driven framework to identify a best-fit linear dynamics model from a sequence of system measurement snapshots,bypassing the nontrivial task of determining appropriate mathemat-ical forms for the breakage kernel functions.A key innovation of our method is the instilling of physics-informed constraints into the DMD eigenmodes and eigenvalues,ensuring they adhere to the physical structure of particle breakage processes even under sparse measurement data.The integration of eigen-constraints is computationally aided by a zeroth-order global optimizer for solving the nonlinear,nonconvex optimization problem that elicits system dynamics from data.Our method is evaluated against the state-of-the-art optimized DMD algorithm using both generated data and real-world data of a batch grinding mill,showcasing over an order of magnitude lower prediction errors in data reconstruction and forecasting.
基金support from the Anusandhan National Research Foundation(ANRF),erstwhile Science and Engineering Research Board(SERB),India,under the startup research grant program(SRG/2022/000566).
文摘The increasing integration of small-scale structures in engineering,particularly in Micro-Electro-Mechanical Systems(MEMS),necessitates advanced modeling approaches to accurately capture their complex mechanical behavior.Classical continuum theories are inadequate at micro-and nanoscales,particularly concerning size effects,singularities,and phenomena like strain softening or phase transitions.This limitation follows from their lack of intrinsic length scale parameters,crucial for representingmicrostructural features.Theoretical and experimental findings emphasize the critical role of these parameters on small scales.This review thoroughly examines various strain gradient elasticity(SGE)theories commonly employed in literature to capture these size-dependent effects on the elastic response.Given the complexity arising from numerous SGE frameworks available in the literature,including first-and second-order gradient theories,we conduct a comprehensive and comparative analysis of common SGE models.This analysis highlights their unique physical interpretations and compares their effectiveness in modeling the size-dependent behavior of low-dimensional structures.A brief discussion on estimating additional material constants,such as intrinsic length scales,is also included to improve the practical relevance of SGE.Following this theoretical treatment,the review covers analytical and numerical methods for solving the associated higher-order governing differential equations.Finally,we present a detailed overview of strain gradient applications in multiscale andmultiphysics response of solids.Interesting research on exploring the relevance of SGE for reduced-order modeling of complex macrostructures,a universal multiphysics coupling in low-dimensional structures without being restricted to limited material symmetries(as in the case of microstructures),is also presented here for interested readers.Finally,we briefly discuss alternative nonlocal elasticity approaches(integral and integro-differential)for incorporating size effects,and conclude with some potential areas for future research on strain gradients.This review aims to provide a clear understanding of strain gradient theories and their broad applicability beyond classical elasticity.
文摘A hybrid Compressed Sensing and Primal-Dual Wavelet(CSP-PDW)technique is proposed for the compression and reconstruction of ECG signals.The compression and reconstruction algorithms are implemented using four key concepts:Sparsifying Basis,Restricted Isometry Principle,Gaussian Random Matrix,and Convex Minimization.In addition to the conventional compression sensing reconstruction approach,wavelet-based processing is employed to enhance reconstruction efficiency.A mathematical model of the proposed algorithm is derived analytically to obtain the essential parameters of compression sensing,including the sparsifying basis,measurement matrix size,and number of iterations required for reconstructing the original signal and determining the type and level of wavelet processing.The low time complexity of the proposed algorithm makes it an ideal candidate for ECG monitoring systems in IoT-based e-healthcare applications.A feature extraction algorithm is also developed to show that the important ECG peaks remain unaltered after reconstruction.The clinical relevance of the reconstructed signal and the efficiency of the developed algorithm are evaluated using four validation parameters at three different compression ratios.
文摘Background:Acute Myeloid Leukemia(AML)is a highly aggressive clonal hematological malignancy with limited treatment options.This study aimed to evaluate the therapeutic potential of nigericin,a polyether ionophore derived from Streptomyces DASNCL-29,as a mitochondrial-targeted agent for AML treatment.Methods:Nigericin was isolated from Streptomyces DASNCL-29 and characterized via chromatography and NMR.Its cytotoxicity was tested in MOLM13(sensitive and venetoclax-resistant)and HL60(sensitive and cytarabine-resistant)cells using the MTT assay.Mitochondrial dysfunction was assessed by measuring reactive oxygen species(ROS),mitochondrial membrane potential(Δψm),and mitochondrial mass.Apoptosis was evaluated with Annexin V/PI assays and immunoblotting,while proteomic analysis was conducted using Liquid Chromatography-Tandem Mass Spectrometry(LC-MS/MS)to identify differentially regulated proteins.Results:Nigericin demonstrated potent cytotoxicity with IC50 values of 57.02 nM in MOLM13-sensitive,35.29 nM in MOLM13-resistant,20.49 nM in HL60-sensitive,and 1.197 nM in HL60-cytarabine-resistant cells.Apoptosis was confirmed by Annexin V/PI staining and caspase-3/PARP cleavage,along with MCL-1 downregulation.Mitochondrial dysfunction was evident from increased ROS,reducedΔψm,and decreased mitochondrial mass.Proteomic profiling identified 264 dysregulated proteins,including a 3.8-fold upregulation of Succinate Dehydrogenase[Ubiquinone]Flavoprotein Subunit A(SDHA).Conclusion:Nigericin induces apoptosis in AML cells by disrupting mitochondrial function and enhancing oxidative stress.Its nanomolar potency highlights the need for further mechanistic studies and in vivo evaluations to explore its potential in AML treatment.
基金supported by the European Commission(EC)under EC grant agreement 101092386 for the Green-VETAfrica project.
文摘The waste management sector plays a vital role in environmental sustainability and public health.However,it faces significant challenges due to a multi-dimensional skills gap that hinders the effective management,processing and disposal of waste.Effective waste management requires increasing levels of technical expertise,analytical proficiency,behavioural skills and digital competence.However,one critical point of concern is the lack of requisite technical skills required for the optimal operation and maintenance of equipment and machinery used for waste management and disposal.Using desk research and focus group interviews of stakeholders in Nigeria and Ghana,we analyzed the skills gap in the sector in order to identify the skills that are currently short in supply in both countries.Our study revealed three broad skills need areas:(1)Skill requirements for youth employment in the waste management sector;(2)Machineries,technologies and tools used for waste management;and(3)Technical skills requirements for green waste management.The study concludes with a mapping of technologies and skills in the waste management sector while highlighting the impact of the existing skills deficit on the sector’s effectiveness and how it can be addressed through structured technical training programs for stakeholders in the sector.
文摘BACKGROUND Spinal tuberculosis(TB),also known as Pott’s spine,remains a significant global health issue,particularly in regions with a high TB burden.The disease presents complex challenges in diagnosis,management,and treatment,prompting a growing interest in research over recent years.The advancements in imaging,diagnostics,and treatment strategies have driven an increased focus on publishing clinical outcomes,review articles,and case series related to spinal TB(STB).AIM To perform a bibliometric analysis of STB research published over the last 5 years(2019-2023)to identify trends in publication volume,contributions by country,and the nature of the research being conducted.METHODS A comprehensive bibliometric analysis was conducted using the PubMed database,focusing on research articles published between 2019 and 2023.Keywords such as“spine tuberculosis,”“spinal TB,”“TB spine,”and“Pott’s spine”were utilized to capture relevant publications.Articles were analyzed based on the type of research(e.g.,case reports,review articles,cohort studies,randomized controlled trials[RCTs]),number of citations,and country of origin based on the corresponding author's details.Further subgroup analysis was performed according to the TB burden in various countries to assess research trends in high-burden regions.RESULTS A total of 528 articles met the inclusion criteria for this bibliometric analysis.The majority of articles were published between 2020 and 2023(440/528;83.3%),while the lowest number was published in 2019(88/528;16.7%).India led the global contributions with 25.8%of the total publications,followed by China(19.9%)and the United States(10.4%).Combined,African countries contributed 6.8%of the research on STB.Regarding the type of articles,case reports and case series dominated the literature(353/528;66.9%),followed by review articles(120/528;22.7%)and cohort studies(45/528;8.5%).Only 1.9%(10/528)of the studies were RCTs.Countries such as the United States,Germany,the United Kingdom,and Japan have pioneered the use of artificial intelligence(AI)in the diagnostic processes for STB,while India,China,South Africa,and other countries have been pivotal in conducting clinical trials and improving clinical management strategies.CONCLUSION This bibliometric analysis revealed a significant increase in STB research over the last 5 years,with India and China being the leading contributors.However,most publications are case reports or case series,with a limited number of RCTs.The results highlighted the need for more high-quality research,especially in terms of RCTs and innovations in diagnostic technologies.Additionally,the application of AI to STB diagnostics shows promise in developed countries,while high-burden countries are focusing on clinical trials and management strategies.
文摘A total of 393 potholes(368 fluvial and 25 marine potholes)were studied at seven different sites in both the fluvial and marine environments.Diverse bedrock properties and large-scale delivery of tools and grinders regulate the dynamic growth,truncation,and amalgamation of potholes.Therefore,the principal objectives of the study are(i)to examine the relationship between the growth of potholes and substrate lithological with structural characteristics(applying geospatial and Schmidt hammer for rock strength analysis)and(ii)to measure the morphology,and size of tools and grinders,processes of truncation and amalgamation in hydro-geomorphic environment using various indices and field techniques.The result showed that large potholes are stretched in the direction of lineament axes and roughly parallel to the river flow direction.Here,the steady growth of pothole depth-diameter is controlled by active bedrock structures,tools,or grinders,and monsoonal high-velocity bank full discharge.Consequently,the deepening and widening of potholes are relatively slow at Bindu,Deuli,and marine beach Neil Island due to fewer structures and little supply of tools or grinders.In small stretches,(Damodar,Subarnarekha,and Rarhu)canyons and gorge-like features(bedrock incision)are formed at Rajrappa,Bhakuyadi,and Guridih sites due to cyclic truncation and amalgamation.Truncation and amalgamation processes restrict the vertical depth threshold value of potholes within 3m,particularly at Rajrappa,Bhakuyadi,and Guridih sites.Scientific study of the pothole's dynamic growth is greatly necessary for the different environmental engineering and river hydraulic projects like excavation,dredging,and dam or barrage construction.Successively,it is essential to compute the cost of rock excavation or dredging,primarily for the mechanical strength of the bedrock river channel and its stability.
基金the National Natural Science Foundation of China(Grant No.52074179)for the financial supportNational Key Research and Development Program of China(2024YFB3713705)is also acknowledged.
文摘Cleanliness control of advanced steels is of vital importance for quality control of the products.In order to understand and control the inclusion removal during refining process in molten steel,its motion behaviors at the multiple steel/gas/slag interfaces have attracted the attention much of metallurgical community.The recent development of the agglomeration of non-metallic inclusions at the steel/Ar and steel/slag interfaces has been summarized,and both the experimental as well as theoretical works have been surveyed.In terms of in situ observation of high-temperature interfacial phenomena in the molten steel,researchers utilized high-temperature confocal laser scanning microscopy to observe the movement of more types of inclusions at the interface,i.e.,the investigated inclusion is no longer limited to Al_(2)O_(3)-based inclusions but moves forward to rare earth oxides,MgO-based oxides,etc.In terms of theoretical models,especially the model of inclusions at the steel/slag interface,the recent development has overcome the limitations of the assumptions of Kralchevsky-Paunov model and verified the possible errors caused by the model assumptions by combining the water model and the physical model.Last but not least,the future work in this topic has been suggested,which could be in combination of thermal physical properties of steels and slag,as well as utilize the artificial intelligence-based methodology to implement a comprehensive inclusion motion behaviors during a comprehensive metallurgical process.
文摘High-temperature confocal laser scanning microscopy(HT-CLSM)is a robust characterization tool which can provide in situ real-time studies of materials processing.This facility has been applied in investigating interfacial phenomena in ironmaking and steelmaking as well as phase transformations during heat treatment of metallic materials.The pioneering work on the application of HTCLSM dates back to twenty-five years ago,to directly observe the crystallization of undercooled steel melt.
文摘Pore pressure(PP)information plays an important role in analysing the geomechanical properties of the reservoir and hydrocarbon field development.PP prediction is an essential requirement to ensure safe drilling operations and it is a fundamental input for well design,and mud weight estimation for wellbore stability.However,the pore pressure trend prediction in complex geological provinces is challenging particularly at oceanic slope setting,where sedimentation rate is relatively high and PP can be driven by various complex geo-processes.To overcome these difficulties,an advanced machine learning(ML)tool is implemented in combination with empirical methods.The empirical method for PP prediction is comprised of data pre-processing and model establishment stage.Eaton's method and Porosity method have been used for PP calculation of the well U1517A located at Tuaheni Landslide Complex of Hikurangi Subduction zone of IODP expedition 372.Gamma-ray,sonic travel time,bulk density and sonic derived porosity are extracted from well log data for the theoretical framework construction.The normal compaction trend(NCT)curve analysis is used to check the optimum fitting of the low permeable zone data.The statistical analysis is done using the histogram analysis and Pearson correlation coefficient matrix with PP data series to identify potential input combinations for ML-based predictive model development.The dataset is prepared and divided into two parts:Training and Testing.The PP data and well log of borehole U1517A is pre-processed to scale in between[-1,+1]to fit into the input range of the non-linear activation/transfer function of the decision tree regression model.The Decision Tree Regression(DTR)algorithm is built and compared to the model performance to predict the PP and identify the overpressure zone in Hikurangi Tuaheni Zone of IODP Expedition 372.
基金supported in part by the Ramanujan Fellowship from the Science and Engineering Research Board,Government of India(Grant No.RJF/2022/000115)。
文摘The breakage of brittle particulate materials into smaller particles under compressive or impact loads can be modelled as an instantiation of the population balance integro-differential equation.In this paper,the emerging computational science paradigm of physics-informed neural networks is studied for the first time for solving both linear and nonlinear variants of the governing dynamics.Unlike conventional methods,the proposed neural network provides rapid simulations of arbitrarily high resolution in particle size,predicting values on arbitrarily fine grids without the need for model retraining.The network is assigned a simple multi-head architecture tailored to uphold monotonicity of the modelled cumulative distribution function over particle sizes.The method is theoretically analyzed and validated against analytical results before being applied to real-world data of a batch grinding mill.The agreement between laboratory data and numerical simulation encourages the use of physics-informed neural nets for optimal planning and control of industrial comminution processes.
基金financially supported by the Natural Science Foundation of Guangdong Province (2022A1515012359)the National Natural Science Foundation of China (21902121)+1 种基金the STU Scientific Research Foundation for Talents (NTF21020)the 2020 Li Ka Shing Foundation Cross-Disciplinary Research Grant (2020LKSFG09A)。
文摘Nafion as a universal polymer ionomer was widely applied for nanocatalysts electrode preparation.However,the effect of Nafion on electrocatalytic performance was often overlooked,especially for CO_(2)electrolysis.Herein,the key roles of Nafion for CO_(2)RR were systematically studied on Cu nanoparticles(NPs)electrocatalyst.We found that Nafion modifier not only inhibit hydrogen evolution reaction(HER)by decreasing the accessibility of H_(2)O from electrolyte to Cu NPs,and increase the CO_(2)concentration at electrocatalyst interface for enhancing the CO_(2)mass transfer process,but also activate CO_(2)molecule by Lewis acid-base interaction between Nafion and CO_(2)to accelerate the formation of^(*)CO,which favor of C–C coupling for boosting C_(2)product generation.Owing to these features,the HER selectivity was suppressed from 40.6%to 16.8%on optimal Cu@Nafion electrode at-1.2 V versus reversible hydrogen electrode(RHE),and as high as 73.5%faradaic efficiencies(FEs)of C_(2)products were achieved at the same applied potential,which was 2.6 times higher than that on bare Cu electrode(~28.3%).In addition,Nafion also contributed to the long-term stability by hinder Cu NPs morphology reconstruction.Thus,this work provides insights into the impact of Nafion on electrocatalytic CO_(2)RR performance.
基金financially supported by the Technion V.P.for Research Fund(No.2023320)。
文摘The monomolecular surface layer of acceptor doped CeO_(2) may become neutral and metallic or charged and semiconducting.This is revealed in the theoretical analysis of the oxygen pressure dependence of the surface defects concentration in acceptor doped ceria with two different dopant types and operated under different oxygen pressures.Recently published experimental data for highly reduced Sm0.2Ce0.8O1.9-x(SDC)containing a fixed valence dopant Sm3+are very different from those published for Pr0.1Ce0.9O_(2)-x(PCO) with the variable valence dopant Pr4+/Pr3+being reduced under milder conditions.The theoretical analysis of these experimental results fits very well the experimental results of SDC and PCO.It leads to the following predictions:the highly reduced surface of SDC is metallic and neutral,the metallic surface electron density of state is gs=0.9×10^(38)J-1·m^(-2)(1.4×1015eV^(-1)·cm^(-2)),the electron effective mass is meff,s=3.3me,and the phase diagram of the reduced surface has theα(fcc)structure as in the bulk.In PCO a double layer is predicted to be formed between the surface and the bulk with the surface being negatively charged and semiconducting.The surface of PCO maintains high Pr^(3+) defect concentration as well as relative high oxygen vacancy concentration at oxygen pressures higher than in the bulk.The reasons for the difference between a metallic and semiconducting surface layer of acceptor doped CeO_(2) are reviewed,as well as the key theoretical considerations applied in coping with this problem.For that we make use of the experimental data and theoretical analysis available for acceptor doped ceria.
文摘In this technologically advancing world,the demand for more energy,oil and gas production is rapidly escalating.To accomplish this,people have inclined more towards completely floating offshore structures,deployed in deep waters.A semi-submersible is selected in the present study,due to its better response characteristics and stability under harsh environmental conditions.The semi-submersible is position restrain with spread mooring lines incorporated with submerged buoy at different locations has been studied.A detailed numerical analysis is carried out using Ansys Aqwa for dynamic response analysis of semi-submersible under the combination of wind,wave,and current forces for 0°,45°,and 90°directions.It was observed that damping ratios and natural periods had been affected based on the position and number of submerged buoys in the mooring system.Also,reduction in mooring force after incorporating buoy in the mooring lines was observed.Subsequently,a Matlab code based on the S-N curve approach was generated and employed to investigate the fatigue damage of mooring lines under dynamic variation of mooring forces.When pegged with submerged buoys,fatigue life of mooring lines is increased under intact and postulated damaged mooring conditions.Moreover,coupling of motion responses of semi-submersible is observed,and unbounded response is not seen in any degrees-offreedom,even during damaged condition of mooring lines.
文摘The present study reported the influence of heavy rare-earth elements(Gd and/or Dy)on Sm-Co-based melt-spun ribbons.Microstructure and magnetic properties of Sm-Co-based(Sm_(1-x)RE_(x)Co_(5))ternary and quaternary systems were investigated.The X-ray diffraction,Auger spectroscopy,scanning electron microscopy(SEM)and transmission electron microscopy(TEM)analyses reveal the presence of the 1:5H and 2:17R phases in the as-spun ribbons.A high-temperature magnetic measurement reports a Curie temperature(Tc)at~825 and~869 K in Sm0.6Gd0.4Co5(ribbon A)and Sm_(0.6)Gd_(0.3)Dy_(0.1)Co_(5)(ribbon B),respectively.A low-temperature magnetic measurement on Sm0.6Gd0.3Dy0.1Co5 ribbons exhibits a type-2 SR(spin reorientation)behaviour at~72 K,which arises due to the presence of the DyCo5 phase.Room temperature magnetic measurements reveal that overall magnetic measurement(OMP)is about 24 and 29.9 for ribbons A and B,respectively.Consequently,the comparative investigations profess that ribbon B shows better magnetic performance due to Dy addition with reduced grain size.This observation indicates that the Gd and Dy substituted Sm-Co magnet can be a potential magnet for high-temperature applications.
文摘Traditional global sensitivity analysis(GSA)neglects the epistemic uncertainties associated with the probabilistic characteristics(i.e.type of distribution type and its parameters)of input rock properties emanating due to the small size of datasets while mapping the relative importance of properties to the model response.This paper proposes an augmented Bayesian multi-model inference(BMMI)coupled with GSA methodology(BMMI-GSA)to address this issue by estimating the imprecision in the momentindependent sensitivity indices of rock structures arising from the small size of input data.The methodology employs BMMI to quantify the epistemic uncertainties associated with model type and parameters of input properties.The estimated uncertainties are propagated in estimating imprecision in moment-independent Borgonovo’s indices by employing a reweighting approach on candidate probabilistic models.The proposed methodology is showcased for a rock slope prone to stress-controlled failure in the Himalayan region of India.The proposed methodology was superior to the conventional GSA(neglects all epistemic uncertainties)and Bayesian coupled GSA(B-GSA)(neglects model uncertainty)due to its capability to incorporate the uncertainties in both model type and parameters of properties.Imprecise Borgonovo’s indices estimated via proposed methodology provide the confidence intervals of the sensitivity indices instead of their fixed-point estimates,which makes the user more informed in the data collection efforts.Analyses performed with the varying sample sizes suggested that the uncertainties in sensitivity indices reduce significantly with the increasing sample sizes.The accurate importance ranking of properties was only possible via samples of large sizes.Further,the impact of the prior knowledge in terms of prior ranges and distributions was significant;hence,any related assumption should be made carefully.
文摘In seismic exploration,it is a critical task to image and interpret different seismic signatures over complex geology due to strong lateral velocity contrast,steep reflectors,overburden strata and dipping flanks.To understand the behavior of these seismic signatures,nowadays Reverse Time Migration(RTM)technique is used extensively by the oil&gas industries.During the extrapolation phase of RTM,the source wavefield needs to be saved,which needs high storage memory and large computing time.These two are the main obstacles of RTM for production use.In order to overcome these disadvantages,in this study,a second-generation improved RTM technique is proposed.In this improved form,a shift operator is introduced at the time of imaging condition of RTM algorithm which is performed automatically both in space and time domain.This effort is made to produce a better-quality image by minimizing the computational time as well as numerical artefacts.The proposed method is applied over various benchmark models and validated by implementing over one field data set from the Jaisalmer Basin,India.From the analysis,it is observed that the method consumes a minimum of 45%less storage space and reduce the execution time by 20%,as compared to conventional RTM.The proposed RTM is found to work efficiently in comparison to the conventional RTM both in terms of imaging quality and minimization of numerical artefacts for all the benchmark models as well as field data.
文摘One of the most dangerous safety hazard in underground coal mines is roof falls during retreat mining.Roof falls may cause life-threatening and non-fatal injuries to miners and impede mining and transportation operations.As a result,a reliable roof fall prediction model is essential to tackle such challenges.Different parameters that substantially impact roof falls are ill-defined and intangible,making this an uncertain and challenging research issue.The National Institute for Occupational Safety and Health assembled a national database of roof performance from 37 coal mines to explore the factors contributing to roof falls.Data acquired for 37 mines is limited due to several restrictions,which increased the likelihood of incompleteness.Fuzzy logic is a technique for coping with ambiguity,incompleteness,and uncertainty.Therefore,In this paper,the fuzzy inference method is presented,which employs a genetic algorithm to create fuzzy rules based on 109 records of roof fall data and pattern search to refine the membership functions of parameters.The performance of the deployed model is evaluated using statistical measures such as the Root-Mean-Square Error,Mean-Absolute-Error,and coefficient of determination(R_(2)).Based on these criteria,the suggested model outperforms the existing models to precisely predict roof fall rates using fewer fuzzy rules.
文摘The present research work attempted to delineate and characterize the reservoir facies from the Dawson Canyon Formation in the Penobscot field,Scotian Basin.An integrated study of instantaneous frequency,P-impedance,volume of clay and neutron-porosity attributes,and structural framework was done to unravel the Late Cretaceous depositional system and reservoir facies distribution patterns within the study area.Fault strikes were found in the EW and NEE-SWW directions indicating the dominant course of tectonic activities during the Late Cretaceous period in the region.P-impedance was estimated using model-based seismic inversion.Petrophysical properties such as the neutron porosity(NPHI)and volume of clay(VCL)were estimated using the multilayer perceptron neural network with high accuracy.Comparatively,a combination of low instantaneous frequency(15-30 Hz),moderate to high impedance(7000-9500 gm/cc*m/s),low neutron porosity(27%-40%)and low volume of clay(40%-60%),suggests fair-to-good sandstone development in the Dawson Canyon Formation.After calibration with the welllog data,it is found that further lowering in these attribute responses signifies the clean sandstone facies possibly containing hydrocarbons.The present study suggests that the shale lithofacies dominates the Late Cretaceous deposition(Dawson Canyon Formation)in the Penobscot field,Scotian Basin.Major faults and overlying shale facies provide structural and stratigraphic seals and act as a suitable hydrocarbon entrapment mechanism in the Dawson Canyon Formation's reservoirs.The present research advocates the integrated analysis of multi-attributes estimated using different methods to minimize the risk involved in hydrocarbon exploration.
基金financially supported by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(Grant No.2022R1I1A1A01069442)the 2024 Hongik University Research Fund。
文摘Salter's duck,an asymmetrical wave energy converter(WEC)device,showed high efficiency in extracting energy from 2D regular waves in the past;yet,challenges remain for fluctuating wave conditions.These can potentially be addressed by adopting a negative stiffness mechanism(NSM)in WEC devices to enhance system efficiency,even in highly nonlinear and steep 3D waves.A weakly nonlinear model was developed which incorporated a nonlinear restoring moment and NSM into the linear formulations and was applied to an asymmetric WEC using a time domain potential flow model.The model was initially validated by comparing it with published experimental and numerical computational fluid dynamics results.The current results were in good agreement with the published results.It was found that the energy extraction increased in the range of 6%to 17%during the evaluation of the effectiveness of the NSM in regular waves.Under irregular wave conditions,specifically at the design wave conditions for the selected test site,the energy extraction increased by 2.4%,with annual energy production increments of approximately 0.8MWh.The findings highlight the potential of NSM in enhancing the performance of asymmetric WEC devices,indicating more efficient energy extraction under various wave conditions.
