Multi<span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">objective optimization problem (MOOP) is an important class of optimization problem that ensures...Multi<span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">objective optimization problem (MOOP) is an important class of optimization problem that ensures users </span><span style="font-family:Verdana;">to </span><span style="font-family:Verdana;">model a large variety of real world applications. In this paper an advanced transformation technique has been proposed to solve MOOP. An algorithm is suggested and the computer application of algorithm has </span><span style="font-family:Verdana;">been </span><span style="font-family:Verdana;">demonstrated by a flow chart. This method is comparatively easy to calculate. Applying on different types of examples, the result indicate</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> that the proposed method gives better solution than other methods and it is less time consuming. Physical presentation and data analysis represent the worth of the method more compactly.</span>展开更多
We show a method to separate the sound field radiated by a signal source from the sound field radiated by noise sources and to reconstruct the sound field radiated by the signal source. The proposed method is based on...We show a method to separate the sound field radiated by a signal source from the sound field radiated by noise sources and to reconstruct the sound field radiated by the signal source. The proposed method is based on reciprocity theorem and the Fourier transform. Both the sound field and its gradient on a measurement surface are needed in the method. Evanescent waves are considered in the method, which ensures a high resolution reconstruction in the near field region of the signal source when evanescent waves can be measured. A simulation is given to verify the method and the influence of measurement noise on the method is discussed.展开更多
A new approach is advanced based on wavelet transform in tandem with autoregressive technique. Wavelets and wavelet packets decompose dynamic signal into different bands and pro- vide multiresolution or multiscale vie...A new approach is advanced based on wavelet transform in tandem with autoregressive technique. Wavelets and wavelet packets decompose dynamic signal into different bands and pro- vide multiresolution or multiscale view of signal. Autoregressive technique possesses effective function for short data processing. The approach is abopted to analyse nonstationary vibration sig- nals of mining excavator. The results indicate that nonstationary operating condition can be moni- tored and diagnosed. Transient toothmeshing frequency and rotating speed are measured. Weak vibration signal of defective ball bearing is extracted from strong vibration of gearbox and diag- nosed successfully. This approach is effective for nonstationary condition monitoring and early di- agnosis of latent fault.展开更多
Wheat, triticale, tritordeum, barley, oat and rye are the most important crops in human consumptions and industry in the world. Transformation technology supplies a new source of improving Triticeae crops. In the past...Wheat, triticale, tritordeum, barley, oat and rye are the most important crops in human consumptions and industry in the world. Transformation technology supplies a new source of improving Triticeae crops. In the past decade, transformation of wheat crops has considerably progressed. Many transgenic plants of Triticeae crops with various genes were produced via nricroprojectile bombardment, Agrobacterium-mediated transformation, PEG-uptake DNA technique, electroporation, microinjection, injection inflorescence and silicone carbide. Integration and expression of transgenes, inheritance and variation of transgenic plants have been studied. Technical improvements of genetic transformation for wheat crops will be extensively useful in commerce and benefit significantly to human being in the world.展开更多
A better understanding of nitrogen transformation in soils could reveal the capacity for biological inorganic N supply and improve the efficiency of N fertilizers. In this study, a15 N tracing study was carried out to...A better understanding of nitrogen transformation in soils could reveal the capacity for biological inorganic N supply and improve the efficiency of N fertilizers. In this study, a15 N tracing study was carried out to investigate the effects of converting woodland to orchard, and orchard age on the gross rates of N transformation occurring simultaneously in subtropical soils in Eastern China. The results showed that inorganic N supply rate was remained constant with soil organic C and N contents increased after converting woodland into citrus orchard and with increasing orchard age. This phenomenon was most probably due to the increase in the turnover time of recalcitrant organic-N, which increased with decreasing soil p H along with increasing orchard age significantly. The amo A gene copy numbers of both archaeal and bacterial were stimulated by orchard planting and increased with increasing orchard age. The nitrification capacity（defined as the ratio of gross rate of nitrification to total gross rate of mineralization） increased following the Michaelis–Menten equation, sharply in the first 10 years after woodland conversion to orchard, and increased continuously but much more slowly till 30 years. Due to the increase in nitrification capacity and unchanged NO3-consumption, the dominance of ammonium in inorganic N in woodland soil was shifted to nitrate dominance in orchard soils. These results indicated that the risk of NO3-loss was expected to increase and the amount of N needed from fertilizers for fruit growth did not change although soil organic N accumulated with orchard age.展开更多
Swelling clays are found extensively in various parts of the world, and sodium-montmorillonite(NaMMT) is the main constituent of an expansive clay mineral. In this work, the swelling behavior of NaMMT clay with a wide...Swelling clays are found extensively in various parts of the world, and sodium-montmorillonite(NaMMT) is the main constituent of an expansive clay mineral. In this work, the swelling behavior of NaMMT clay with a wide range of organic fluids, high polar through low polar fluids, is studied using a combination of Fourier transform infrared(FTIR) technique and molecular dynamics(MD) simulations.The construction of the representative clayefluid models is carried out, and the nature of nonbonded interactions between clay and fluids is studied using MD. Our FTIR and MD simulations results suggest the significant nonbonded interactions between Na-MMT clay and polar fluids, such as formamide and water. The nonbonded interactions of Na-MMT with methanol and acetone are significantly less than those in Na-MMT with polar fluids. The interactions of the fluids with various entities of the clay such as Sie O, Fee OH, Mge OH, and Ale OH captured via the spectroscopy experiments and modeling provide a finer understanding of the interactions and their contributions to swelling. The MD simulations are able to capture the band shifts observed in the spectra obtained in the spectroscopy experiments. This work also captures the conformations of interlayer sodium ions with formamide, water, methanol, and acetone during swelling. These nonbonded interactions provide insight into the molecular mechanism that the polarity of fluids plays an important role in the initiation of interlayer swelling, alteration in the orientations, and evolution of microstructure of swelling clays at the molecular scale.展开更多
BACKGROUND Implant fracture is one of the most serious mechanical complications of dental implants.Conventional treatment necessitates visibility of the apical portion of the fractured implant,whereas for deep and inv...BACKGROUND Implant fracture is one of the most serious mechanical complications of dental implants.Conventional treatment necessitates visibility of the apical portion of the fractured implant,whereas for deep and invisible implant fractures,the traditional trephine method has been ineffective.Surgical removal of the marginal bone to expose the fracture surface would be a time-consuming and extensively damaging procedure.Here,we propose a novel technique to address invisible implant fractures.CASE SUMMARY A 50-year-old woman was referred to our department with the chief complaint that her right mandibular implant tooth had fallen out 3 mo earlier.Cone-beam computed tomography examination showed an implant fracture with a fracture surface 5.1 mm below the crestal ridge.The patient was treated with osteotomy combined with the trephine technique to expose the surgical field and remove the implant.The invisible fractured implant was successfully removed,with minimal trauma.A modified Wafer technique-supported guided bone regeneration treatment was then administered to restore the buccal bone wall and preserve the bone mass.Six months later,fine regenerative bone and a wide alveolar crest in the edentulous area were observed,and a new implant was placed.Four months later,restoration was completed using a cemented ceramic prosthesis.Clinical and radiographic examinations 12 mo after loading fulfilled the success criteria.The patient reported no complaints and was satisfied.CONCLUSION Osteotomy combined with the trephine technique can be effectively used to address deep and invisible implant fractures.展开更多
The study deals with the multi-choice mathematical programming problem, where the right hand side of the constraints is multi-choice in nature. However, the problem of multi-choice linear programming cannot be solved ...The study deals with the multi-choice mathematical programming problem, where the right hand side of the constraints is multi-choice in nature. However, the problem of multi-choice linear programming cannot be solved directly by standard linear or nonlinear programming techniques. The aim of this paper is to transform such problems to a standard mathematical linear programming problem. For each constraint, exactly one parameter value is selected out of a multiple number of parameter values. This process of selection can be established in different ways. In this paper, we present a new simple technique enabling us to handle such problem as a mixed integer linear programming problem and consequently solve them by using standard linear programming software. Our main aim depends on inserting a specific number of binary variables and using them to construct a linear combination which gives just one parameter among the multiple choice values for each choice of the values of the binary variables. A numerical example is presented to illustrate our analysis.展开更多
As oil and gas exploration moves into deeper waters,marine risers are subjected to increasingly complex service conditions,including vessel motions,ocean currents,seabed-soil interactions,and internal flow effects.Thi...As oil and gas exploration moves into deeper waters,marine risers are subjected to increasingly complex service conditions,including vessel motions,ocean currents,seabed-soil interactions,and internal flow effects.This work establishes a dynamic behavior model of steel catenary risers(SCRs)with varying curvatures subjected to internal flow and external currents and considers the effects of pipe-soil interactions on the curvature profile.The governing equation is solved via the generalized integral transform technique(GITT),which yields a semi-analytical solution of a high-order nonlinear partial differential equation.Parametric studies are then performed to analyze the effects of varying curvature on the vibration frequency and amplitude of SCRs.The vibration frequency and amplitude increase with the touchdown angle and hang-off angle,although the effect of the hang-off angle is negligible.Additionally,as the curvature increases along the centerline axis,the position of the maximum amplitude of the SCR moves upward.展开更多
Hybrid nanofluids have gained significant attention for their superior thermal and rheological characteristics,offering immense potential in energy conversion,biomedical transport,and electromagnetic flow control syst...Hybrid nanofluids have gained significant attention for their superior thermal and rheological characteristics,offering immense potential in energy conversion,biomedical transport,and electromagnetic flow control systems.Understanding their dynamic behavior under coupled magnetic,rotational,and reactive effects is crucial for the development of efficient thermal management technologies.This study develops a neuro-fuzzy computational framework to examine the dynamics of a reactive Cu–TiO_(2)–H_(2)Ohybrid nanofluid flowing through a squarely elevated Riga tunnel.The governing model incorporates Hall and ion-slip effects,thermal radiation,and first-order chemical reactions under ramped thermo-solutal boundary conditions and rotational electromagnetic forces.Closed-form analytical solutions are derived via the Laplace transform method to describe the transient velocity,temperature,and concentration fields.To complement and validate the analytical model,an artificial neural network(ANN)optimized using the Levenberg–Marquardt backpropagation algorithm(ANN-LMBPA)is trained on datasets generated in Mathematica.Regression and error analyses confirm the model’s predictive robustness,with mean squared errors ranging between 10^(-4) and 10^(-9).In addition,an Adaptive Neuro-Fuzzy Inference System(ANFIS)is developed to estimate the heat transfer rate(HTR),achieving aminimal RMSE of 0.011012 for the heat transfer coefficient(HTC).The findings reveal that rotational motion and Hall–ion slip effects suppress primary velocity but enhance secondary flow,while the modified Hartmann number(Lorentz force)accelerates both components.Thermal radiation increases fluid temperature,whereas higher Schmidt numbers and reaction rates diminish solute concentration.The HTR decreases with increasing radiation and nanoparticle volume fraction,while the mass transfer rate(MTR)improves under stronger chemical reactivity.Overall,the proposed hybrid analytical–AI framework demonstrates high accuracy and efficiency,offering valuable insights for the design and optimization of electromagnetic nanofluid systems in advanced thermal and process engineering applications.展开更多
Tunnel stability control is a world-wide difficult problem. For the sake of solving it,the new theory of soft rock engineering mechanics has been estabilished. Some key points,such as the definition and classification...Tunnel stability control is a world-wide difficult problem. For the sake of solving it,the new theory of soft rock engineering mechanics has been estabilished. Some key points,such as the definition and classification of soft rock, mechanical deformation mechanism of a soft rock tunnel, the critical support technique of soft rock tunnel and the new theory of the soft rock tunnel stability control are proposed in this paper.展开更多
A torsional static and free vibration analysis of the functionally graded nanotube(FGNT)composed of two materials varying continuously according to the power-law along the radial direction is performed using the bi-He...A torsional static and free vibration analysis of the functionally graded nanotube(FGNT)composed of two materials varying continuously according to the power-law along the radial direction is performed using the bi-Helmholtz kernel based stress-driven nonlocal integral model.The differential governing equation and boundary conditions are deduced on the basis of Hamilton’s principle,and the constitutive relationship is expressed as an integral equation with the bi-Helmholtz kernel.Several nominal variables are introduced to simplify the differential governing equation,integral constitutive equation,and boundary conditions.Rather than transforming the constitutive equation from integral to differential forms,the Laplace transformation is used directly to solve the integro-differential equations.The explicit expression for nominal torsional rotation and torque contains four unknown constants,which can be determined with the help of two boundary conditions and two extra constraints from the integral constitutive relation.A few benchmarked examples are solved to illustrate the nonlocal influence on the static torsion of a clamped-clamped(CC)FGNT under torsional constraints and a clamped-free(CF)FGNT under concentrated and uniformly distributed torques as well as the torsional free vibration of an FGNT under different boundary conditions.展开更多
Based on the Euler-Bernoulli beam theory and Kelvin-Voigt model,a nonlinear model for the transverse vibration of a pipe under the combined action of base motion and pulsating internal flow is established.The governin...Based on the Euler-Bernoulli beam theory and Kelvin-Voigt model,a nonlinear model for the transverse vibration of a pipe under the combined action of base motion and pulsating internal flow is established.The governing partial differential equation is transformed into a nonlinear system of fourth-order ordinary differential equations by using the generalized integral transform technique(GITT).The effects of the combined excitation of base motion and pulsating internal flow on the nonlinear dynamic behavior of the pipe are investigated using a bifurcation diagram,phase trajectory diagram,power spectrum diagram,time-domain diagram,and Poincare map.The results show that the base excitation amplitude and frequency significantly affect the dynamic behavior of the pipe system.Some new resonance phenomena can be observed,such as the period-1 motion under the base excitation or the pulsating internal flow alone becomes the multi-periodic motion,quasi-periodic motion or even chaotic motion due to the combined excitation action.展开更多
In situ observation of electron backscattering diffraction technique was used to evaluate the orientation relationships between austenite and α′-martensite（α′-M） for high manganese transformation-induced plastic...In situ observation of electron backscattering diffraction technique was used to evaluate the orientation relationships between austenite and α′-martensite（α′-M） for high manganese transformation-induced plasticity steel.It was noted that different from the thermal martensite,which well obeyed K-S relationship with austenite,the orientation relationship between deformation-induced α′-M with austenite changed during deformation,namely K-S and N-W relations coexisted.No clear differences existed between α′-M variants with two kinds of relationships in terms of martensitic orientation,shape and the misorientation between α′-M variants.And this phenomenon happened in almost all austenitic grains with different orientations investigated in this study.An atom displacement mechanism through conjugate complex slips of partial dislocations in the distorted fcc lattice was applied in this article to interpret the coexistence of K-S and N-W relationships.展开更多
The problem of an anti-plane Griffith crack moving along the interface of dissimilar piezoelectric materials is solved by using the integral transform technique. It is shown from the result that the intensity factors ...The problem of an anti-plane Griffith crack moving along the interface of dissimilar piezoelectric materials is solved by using the integral transform technique. It is shown from the result that the intensity factors of anti-plane stress and electric displacement around the crack tip are dependent on the speed of the Griffith crack as well as the material coefficients. When the two piezoelectric materials are identical, the present result will be reduced to the result far the problem of an anti-plane moving Griffith crack in homogeneous piezoelectric materials.展开更多
The present article aims to examine the heat and mass distribution in a free convection flow of electrically conducted,generalized Jeffrey nanofluid in a heated rotatory system.The flow analysis is considered in the p...The present article aims to examine the heat and mass distribution in a free convection flow of electrically conducted,generalized Jeffrey nanofluid in a heated rotatory system.The flow analysis is considered in the presence of thermal radiation and the transverse magnetic field of strength B0.The medium is porous accepting generalized Darcy’s law.The motion of the fluid is due to the cosine oscillations of the plate.Nanofluid has been formed by the uniform dispersing of the Silver nanoparticles in regular engine oil.The problem has been modeled in the form of classical partial differential equations and then generalized by replacing time derivative with Atangana–Baleanu(AB)time-fractional derivative.Upon taking the Laplace transform technique(LTT)and using physical boundary conditions,exact expressions have been obtained for momentum,energy,and concentration distributions.The impact of a number of parameters on fluid flow is shown graphically.The numerical tables have been computed for variation in the rate of heat and mass transfer with respect to rooted parameters.Finally,the classical solution is recovered by taking the fractional parameter approaching unity.It is worth noting that by adding silver nanoparticles in regular engine oil,its heat transfer rate increased by 14.59%,which will improve the life and workability of the engine.展开更多
A study is presented for the large deflection dynamic response of rigid- plastic circular plate resting on potential fluid under a rectangular pressure pulse load. By virtue of Hankel integral transform technique,this...A study is presented for the large deflection dynamic response of rigid- plastic circular plate resting on potential fluid under a rectangular pressure pulse load. By virtue of Hankel integral transform technique,this interaction problem is reduced to a problem of dynamic plastic response of the plate in vacuum.The closed-form solutions are derived for both middle and high pressure loads by solving the equations of motion with the large deflection in the range where both bending moments and membrane forces are important.Some numerical results are given.展开更多
An extended dielectric crack model is proposed to capture the effects of the physical properties of crack interior on crack-tip thermoelectroelastic fields.The typical crack-face boundary conditions can be retrieved b...An extended dielectric crack model is proposed to capture the effects of the physical properties of crack interior on crack-tip thermoelectroelastic fields.The typical crack-face boundary conditions can be retrieved by considering the limiting cases of electrical permeability and thermal conductivity inside a crack.Making use of the Fourier transform technique,the problem of a thermopiezoelectric strip weakened by a Griffith crack is investigated and transformed to solve the system of the second kind Fredholm integral equations with Cauchy kernel.The Lobatto-Chebyshev collocation method is used to form a nonlinear system of algebraic equations,which is solved by elaborating on an algorithm.The crack-tip thermoelectroelastic fields are determined by using the approximate solutions.Numerical simulations are carried out to show the variations of the fracture parameters of concern under applied thermoelectromechanical loads,the physical properties of the dielectric medium inside the crack and the geometry of the cracked thermopiezoelectric strip.Some comparisons with the experimental results are reported to reveal the effectiveness of the extended dielectric crack model.展开更多
We present a new iterative reconstruction algorithm to improve the algebraic reconstruction technique （ART） for the Single-Photon Emission Computed Tomography. Our method is a generalization of the Kaczmarz iterativ...We present a new iterative reconstruction algorithm to improve the algebraic reconstruction technique （ART） for the Single-Photon Emission Computed Tomography. Our method is a generalization of the Kaczmarz iterative algorithm for solving linear systems of equations and introduces exact and implicit attenuation correction derived from the attenuated Radon transform operator at each step of the algorithm. The performances of the presented algorithm have been tested upon various numerical experiments in presence of both strongly non-uniform attenuation and incomplete measurements data. We also tested the ability of our algorithm to handle moderate noisy data. Simulation studies demonstrate that the proposed method has a significant improvement in the quality of reconstructed images over ART. Moreover, convergence speed was improved and stability was established, facing noisy data, once we incorporate filtration procedure in our algorithm.展开更多
Real-time wide-area environment sensing is crucial for accessing open-world information streams from nature and human society.As a transformative technique distinct from electrical sensors,distributed optical fiber se...Real-time wide-area environment sensing is crucial for accessing open-world information streams from nature and human society.As a transformative technique distinct from electrical sensors,distributed optical fiber sensing especially for Brillouin scattering-based paradigm has shown superior bandwidth,power,and sensing range.Still,it suffers from insufficient resolution and timeliness to characterize remote dynamic events.Here we develop TABS—a transient acoustic wave-based Brillouin optical time domain analysis sensor,supporting long-range highspatiotemporal-resolution distributed sensing.By designing a functionally synergistic sensor architecture,TABS elaborately leverages wideband and time-weighted energy transformation properties of a transient acousto-optic interaction to breaking through Brillouin-energy-utilization-efficiency bottleneck,enabling enhancements in overall sensing performance.In the experiment,TABS has achieved a 37-cm spatial resolution over a 50-km range with 1 to 2 orders of magnitude improvement in temporal resolution compared to prevailing Brillouin sensing approaches.For the first time,TABS is explored for state imaging of evacuated-tube maglev transportation system as an exemplary application,showcasing its feasibility and flexibility for potential open-world applications and large-scale intelligent perception.展开更多
文摘Multi<span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">objective optimization problem (MOOP) is an important class of optimization problem that ensures users </span><span style="font-family:Verdana;">to </span><span style="font-family:Verdana;">model a large variety of real world applications. In this paper an advanced transformation technique has been proposed to solve MOOP. An algorithm is suggested and the computer application of algorithm has </span><span style="font-family:Verdana;">been </span><span style="font-family:Verdana;">demonstrated by a flow chart. This method is comparatively easy to calculate. Applying on different types of examples, the result indicate</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> that the proposed method gives better solution than other methods and it is less time consuming. Physical presentation and data analysis represent the worth of the method more compactly.</span>
基金Supported by the National Natural Science Foundation of China under Grant Nos 11374270 and 11674294
文摘We show a method to separate the sound field radiated by a signal source from the sound field radiated by noise sources and to reconstruct the sound field radiated by the signal source. The proposed method is based on reciprocity theorem and the Fourier transform. Both the sound field and its gradient on a measurement surface are needed in the method. Evanescent waves are considered in the method, which ensures a high resolution reconstruction in the near field region of the signal source when evanescent waves can be measured. A simulation is given to verify the method and the influence of measurement noise on the method is discussed.
文摘A new approach is advanced based on wavelet transform in tandem with autoregressive technique. Wavelets and wavelet packets decompose dynamic signal into different bands and pro- vide multiresolution or multiscale view of signal. Autoregressive technique possesses effective function for short data processing. The approach is abopted to analyse nonstationary vibration sig- nals of mining excavator. The results indicate that nonstationary operating condition can be moni- tored and diagnosed. Transient toothmeshing frequency and rotating speed are measured. Weak vibration signal of defective ball bearing is extracted from strong vibration of gearbox and diag- nosed successfully. This approach is effective for nonstationary condition monitoring and early di- agnosis of latent fault.
文摘Wheat, triticale, tritordeum, barley, oat and rye are the most important crops in human consumptions and industry in the world. Transformation technology supplies a new source of improving Triticeae crops. In the past decade, transformation of wheat crops has considerably progressed. Many transgenic plants of Triticeae crops with various genes were produced via nricroprojectile bombardment, Agrobacterium-mediated transformation, PEG-uptake DNA technique, electroporation, microinjection, injection inflorescence and silicone carbide. Integration and expression of transgenes, inheritance and variation of transgenic plants have been studied. Technical improvements of genetic transformation for wheat crops will be extensively useful in commerce and benefit significantly to human being in the world.
基金supported by the National Natural Science Foundation of China (Nos.41401339, 41330744)the Natural Science Foundation of Jiangsu Province (No.BK20140062)and Fujian Province (No.2014J01145)
文摘A better understanding of nitrogen transformation in soils could reveal the capacity for biological inorganic N supply and improve the efficiency of N fertilizers. In this study, a15 N tracing study was carried out to investigate the effects of converting woodland to orchard, and orchard age on the gross rates of N transformation occurring simultaneously in subtropical soils in Eastern China. The results showed that inorganic N supply rate was remained constant with soil organic C and N contents increased after converting woodland into citrus orchard and with increasing orchard age. This phenomenon was most probably due to the increase in the turnover time of recalcitrant organic-N, which increased with decreasing soil p H along with increasing orchard age significantly. The amo A gene copy numbers of both archaeal and bacterial were stimulated by orchard planting and increased with increasing orchard age. The nitrification capacity（defined as the ratio of gross rate of nitrification to total gross rate of mineralization） increased following the Michaelis–Menten equation, sharply in the first 10 years after woodland conversion to orchard, and increased continuously but much more slowly till 30 years. Due to the increase in nitrification capacity and unchanged NO3-consumption, the dominance of ammonium in inorganic N in woodland soil was shifted to nitrate dominance in orchard soils. These results indicated that the risk of NO3-loss was expected to increase and the amount of N needed from fertilizers for fruit growth did not change although soil organic N accumulated with orchard age.
基金the support of USDoT,Mountain Plains Consortium,UGPTI under grant No.#69A3551747108
文摘Swelling clays are found extensively in various parts of the world, and sodium-montmorillonite(NaMMT) is the main constituent of an expansive clay mineral. In this work, the swelling behavior of NaMMT clay with a wide range of organic fluids, high polar through low polar fluids, is studied using a combination of Fourier transform infrared(FTIR) technique and molecular dynamics(MD) simulations.The construction of the representative clayefluid models is carried out, and the nature of nonbonded interactions between clay and fluids is studied using MD. Our FTIR and MD simulations results suggest the significant nonbonded interactions between Na-MMT clay and polar fluids, such as formamide and water. The nonbonded interactions of Na-MMT with methanol and acetone are significantly less than those in Na-MMT with polar fluids. The interactions of the fluids with various entities of the clay such as Sie O, Fee OH, Mge OH, and Ale OH captured via the spectroscopy experiments and modeling provide a finer understanding of the interactions and their contributions to swelling. The MD simulations are able to capture the band shifts observed in the spectra obtained in the spectroscopy experiments. This work also captures the conformations of interlayer sodium ions with formamide, water, methanol, and acetone during swelling. These nonbonded interactions provide insight into the molecular mechanism that the polarity of fluids plays an important role in the initiation of interlayer swelling, alteration in the orientations, and evolution of microstructure of swelling clays at the molecular scale.
文摘BACKGROUND Implant fracture is one of the most serious mechanical complications of dental implants.Conventional treatment necessitates visibility of the apical portion of the fractured implant,whereas for deep and invisible implant fractures,the traditional trephine method has been ineffective.Surgical removal of the marginal bone to expose the fracture surface would be a time-consuming and extensively damaging procedure.Here,we propose a novel technique to address invisible implant fractures.CASE SUMMARY A 50-year-old woman was referred to our department with the chief complaint that her right mandibular implant tooth had fallen out 3 mo earlier.Cone-beam computed tomography examination showed an implant fracture with a fracture surface 5.1 mm below the crestal ridge.The patient was treated with osteotomy combined with the trephine technique to expose the surgical field and remove the implant.The invisible fractured implant was successfully removed,with minimal trauma.A modified Wafer technique-supported guided bone regeneration treatment was then administered to restore the buccal bone wall and preserve the bone mass.Six months later,fine regenerative bone and a wide alveolar crest in the edentulous area were observed,and a new implant was placed.Four months later,restoration was completed using a cemented ceramic prosthesis.Clinical and radiographic examinations 12 mo after loading fulfilled the success criteria.The patient reported no complaints and was satisfied.CONCLUSION Osteotomy combined with the trephine technique can be effectively used to address deep and invisible implant fractures.
文摘The study deals with the multi-choice mathematical programming problem, where the right hand side of the constraints is multi-choice in nature. However, the problem of multi-choice linear programming cannot be solved directly by standard linear or nonlinear programming techniques. The aim of this paper is to transform such problems to a standard mathematical linear programming problem. For each constraint, exactly one parameter value is selected out of a multiple number of parameter values. This process of selection can be established in different ways. In this paper, we present a new simple technique enabling us to handle such problem as a mixed integer linear programming problem and consequently solve them by using standard linear programming software. Our main aim depends on inserting a specific number of binary variables and using them to construct a linear combination which gives just one parameter among the multiple choice values for each choice of the values of the binary variables. A numerical example is presented to illustrate our analysis.
基金financially supported by the National Natural Science Foundation of China(Grant No.52201312).
文摘As oil and gas exploration moves into deeper waters,marine risers are subjected to increasingly complex service conditions,including vessel motions,ocean currents,seabed-soil interactions,and internal flow effects.This work establishes a dynamic behavior model of steel catenary risers(SCRs)with varying curvatures subjected to internal flow and external currents and considers the effects of pipe-soil interactions on the curvature profile.The governing equation is solved via the generalized integral transform technique(GITT),which yields a semi-analytical solution of a high-order nonlinear partial differential equation.Parametric studies are then performed to analyze the effects of varying curvature on the vibration frequency and amplitude of SCRs.The vibration frequency and amplitude increase with the touchdown angle and hang-off angle,although the effect of the hang-off angle is negligible.Additionally,as the curvature increases along the centerline axis,the position of the maximum amplitude of the SCR moves upward.
文摘Hybrid nanofluids have gained significant attention for their superior thermal and rheological characteristics,offering immense potential in energy conversion,biomedical transport,and electromagnetic flow control systems.Understanding their dynamic behavior under coupled magnetic,rotational,and reactive effects is crucial for the development of efficient thermal management technologies.This study develops a neuro-fuzzy computational framework to examine the dynamics of a reactive Cu–TiO_(2)–H_(2)Ohybrid nanofluid flowing through a squarely elevated Riga tunnel.The governing model incorporates Hall and ion-slip effects,thermal radiation,and first-order chemical reactions under ramped thermo-solutal boundary conditions and rotational electromagnetic forces.Closed-form analytical solutions are derived via the Laplace transform method to describe the transient velocity,temperature,and concentration fields.To complement and validate the analytical model,an artificial neural network(ANN)optimized using the Levenberg–Marquardt backpropagation algorithm(ANN-LMBPA)is trained on datasets generated in Mathematica.Regression and error analyses confirm the model’s predictive robustness,with mean squared errors ranging between 10^(-4) and 10^(-9).In addition,an Adaptive Neuro-Fuzzy Inference System(ANFIS)is developed to estimate the heat transfer rate(HTR),achieving aminimal RMSE of 0.011012 for the heat transfer coefficient(HTC).The findings reveal that rotational motion and Hall–ion slip effects suppress primary velocity but enhance secondary flow,while the modified Hartmann number(Lorentz force)accelerates both components.Thermal radiation increases fluid temperature,whereas higher Schmidt numbers and reaction rates diminish solute concentration.The HTR decreases with increasing radiation and nanoparticle volume fraction,while the mass transfer rate(MTR)improves under stronger chemical reactivity.Overall,the proposed hybrid analytical–AI framework demonstrates high accuracy and efficiency,offering valuable insights for the design and optimization of electromagnetic nanofluid systems in advanced thermal and process engineering applications.
文摘Tunnel stability control is a world-wide difficult problem. For the sake of solving it,the new theory of soft rock engineering mechanics has been estabilished. Some key points,such as the definition and classification of soft rock, mechanical deformation mechanism of a soft rock tunnel, the critical support technique of soft rock tunnel and the new theory of the soft rock tunnel stability control are proposed in this paper.
基金Project supported by the National Natural Science Foundation of China(No.11672131)the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘A torsional static and free vibration analysis of the functionally graded nanotube(FGNT)composed of two materials varying continuously according to the power-law along the radial direction is performed using the bi-Helmholtz kernel based stress-driven nonlocal integral model.The differential governing equation and boundary conditions are deduced on the basis of Hamilton’s principle,and the constitutive relationship is expressed as an integral equation with the bi-Helmholtz kernel.Several nominal variables are introduced to simplify the differential governing equation,integral constitutive equation,and boundary conditions.Rather than transforming the constitutive equation from integral to differential forms,the Laplace transformation is used directly to solve the integro-differential equations.The explicit expression for nominal torsional rotation and torque contains four unknown constants,which can be determined with the help of two boundary conditions and two extra constraints from the integral constitutive relation.A few benchmarked examples are solved to illustrate the nonlocal influence on the static torsion of a clamped-clamped(CC)FGNT under torsional constraints and a clamped-free(CF)FGNT under concentrated and uniformly distributed torques as well as the torsional free vibration of an FGNT under different boundary conditions.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.52171288,51890914)the Key Research and Development Program of Shandong Province(Major Innovation Project)(Grant No.2022CXGC020405)+1 种基金the National Ministry of Industry and Information Technology Innovation Special Project-Engineering Demonstration Application of Subsea Oil and Gas Production SystemSubject 4:Research on Subsea Christmas Tree and Wellhead Offshore Testing Technology(Grant No.MC-201901-S01-04)CNPq,CAPES and FAPERJ of Brazil。
文摘Based on the Euler-Bernoulli beam theory and Kelvin-Voigt model,a nonlinear model for the transverse vibration of a pipe under the combined action of base motion and pulsating internal flow is established.The governing partial differential equation is transformed into a nonlinear system of fourth-order ordinary differential equations by using the generalized integral transform technique(GITT).The effects of the combined excitation of base motion and pulsating internal flow on the nonlinear dynamic behavior of the pipe are investigated using a bifurcation diagram,phase trajectory diagram,power spectrum diagram,time-domain diagram,and Poincare map.The results show that the base excitation amplitude and frequency significantly affect the dynamic behavior of the pipe system.Some new resonance phenomena can be observed,such as the period-1 motion under the base excitation or the pulsating internal flow alone becomes the multi-periodic motion,quasi-periodic motion or even chaotic motion due to the combined excitation action.
基金financially supported by the National Natural Science Foundation of China(No.51271028)
文摘In situ observation of electron backscattering diffraction technique was used to evaluate the orientation relationships between austenite and α′-martensite（α′-M） for high manganese transformation-induced plasticity steel.It was noted that different from the thermal martensite,which well obeyed K-S relationship with austenite,the orientation relationship between deformation-induced α′-M with austenite changed during deformation,namely K-S and N-W relations coexisted.No clear differences existed between α′-M variants with two kinds of relationships in terms of martensitic orientation,shape and the misorientation between α′-M variants.And this phenomenon happened in almost all austenitic grains with different orientations investigated in this study.An atom displacement mechanism through conjugate complex slips of partial dislocations in the distorted fcc lattice was applied in this article to interpret the coexistence of K-S and N-W relationships.
基金the National Natural Science Foundationthe National Post-doctoral Science Foundation of China
文摘The problem of an anti-plane Griffith crack moving along the interface of dissimilar piezoelectric materials is solved by using the integral transform technique. It is shown from the result that the intensity factors of anti-plane stress and electric displacement around the crack tip are dependent on the speed of the Griffith crack as well as the material coefficients. When the two piezoelectric materials are identical, the present result will be reduced to the result far the problem of an anti-plane moving Griffith crack in homogeneous piezoelectric materials.
文摘The present article aims to examine the heat and mass distribution in a free convection flow of electrically conducted,generalized Jeffrey nanofluid in a heated rotatory system.The flow analysis is considered in the presence of thermal radiation and the transverse magnetic field of strength B0.The medium is porous accepting generalized Darcy’s law.The motion of the fluid is due to the cosine oscillations of the plate.Nanofluid has been formed by the uniform dispersing of the Silver nanoparticles in regular engine oil.The problem has been modeled in the form of classical partial differential equations and then generalized by replacing time derivative with Atangana–Baleanu(AB)time-fractional derivative.Upon taking the Laplace transform technique(LTT)and using physical boundary conditions,exact expressions have been obtained for momentum,energy,and concentration distributions.The impact of a number of parameters on fluid flow is shown graphically.The numerical tables have been computed for variation in the rate of heat and mass transfer with respect to rooted parameters.Finally,the classical solution is recovered by taking the fractional parameter approaching unity.It is worth noting that by adding silver nanoparticles in regular engine oil,its heat transfer rate increased by 14.59%,which will improve the life and workability of the engine.
基金The study is supported by National Natural Science Foundation of China.
文摘A study is presented for the large deflection dynamic response of rigid- plastic circular plate resting on potential fluid under a rectangular pressure pulse load. By virtue of Hankel integral transform technique,this interaction problem is reduced to a problem of dynamic plastic response of the plate in vacuum.The closed-form solutions are derived for both middle and high pressure loads by solving the equations of motion with the large deflection in the range where both bending moments and membrane forces are important.Some numerical results are given.
基金supported by the National Natural Science Foundation of China(Nos.11872155 and 11362002)the Guangxi Natural Science Foundation(No.2016GXNSFAA380261)the innovation project of Guangxi Graduate Education(YCSW2019045).
文摘An extended dielectric crack model is proposed to capture the effects of the physical properties of crack interior on crack-tip thermoelectroelastic fields.The typical crack-face boundary conditions can be retrieved by considering the limiting cases of electrical permeability and thermal conductivity inside a crack.Making use of the Fourier transform technique,the problem of a thermopiezoelectric strip weakened by a Griffith crack is investigated and transformed to solve the system of the second kind Fredholm integral equations with Cauchy kernel.The Lobatto-Chebyshev collocation method is used to form a nonlinear system of algebraic equations,which is solved by elaborating on an algorithm.The crack-tip thermoelectroelastic fields are determined by using the approximate solutions.Numerical simulations are carried out to show the variations of the fracture parameters of concern under applied thermoelectromechanical loads,the physical properties of the dielectric medium inside the crack and the geometry of the cracked thermopiezoelectric strip.Some comparisons with the experimental results are reported to reveal the effectiveness of the extended dielectric crack model.
文摘We present a new iterative reconstruction algorithm to improve the algebraic reconstruction technique （ART） for the Single-Photon Emission Computed Tomography. Our method is a generalization of the Kaczmarz iterative algorithm for solving linear systems of equations and introduces exact and implicit attenuation correction derived from the attenuated Radon transform operator at each step of the algorithm. The performances of the presented algorithm have been tested upon various numerical experiments in presence of both strongly non-uniform attenuation and incomplete measurements data. We also tested the ability of our algorithm to handle moderate noisy data. Simulation studies demonstrate that the proposed method has a significant improvement in the quality of reconstructed images over ART. Moreover, convergence speed was improved and stability was established, facing noisy data, once we incorporate filtration procedure in our algorithm.
基金supported in part by National Natural Science Foundation of China(NSFC)under contracts Nos.U23A20376,62431024,61735015,62405153,62205176.
文摘Real-time wide-area environment sensing is crucial for accessing open-world information streams from nature and human society.As a transformative technique distinct from electrical sensors,distributed optical fiber sensing especially for Brillouin scattering-based paradigm has shown superior bandwidth,power,and sensing range.Still,it suffers from insufficient resolution and timeliness to characterize remote dynamic events.Here we develop TABS—a transient acoustic wave-based Brillouin optical time domain analysis sensor,supporting long-range highspatiotemporal-resolution distributed sensing.By designing a functionally synergistic sensor architecture,TABS elaborately leverages wideband and time-weighted energy transformation properties of a transient acousto-optic interaction to breaking through Brillouin-energy-utilization-efficiency bottleneck,enabling enhancements in overall sensing performance.In the experiment,TABS has achieved a 37-cm spatial resolution over a 50-km range with 1 to 2 orders of magnitude improvement in temporal resolution compared to prevailing Brillouin sensing approaches.For the first time,TABS is explored for state imaging of evacuated-tube maglev transportation system as an exemplary application,showcasing its feasibility and flexibility for potential open-world applications and large-scale intelligent perception.
