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Determination of uncertainties of geomechanical parameters of metamorphic rocks using petrographic analyses

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第2期16卷 345-364页

作者： Behzad Dastjerdy Ali Saeidi Shahriyar Heidarzadeh department of applied Sciences University of Quebec at ChicoutimiSaguenayQCCanada SNC-Lavalin MontrealCanada

Geomechanical parameters of intact metamorphic rocks determined from laboratory testing remain highly uncertain because of the great intrinsic variability associated with the degrees of *** aim of this paper is to develop a proper methodology to analyze the uncertainties of geomechanical characteristics by focusing on three domains,*** treatment process,schistosity angle,and ***,the variabilities of the geomechanical laboratory data of Westwood Mine(Quebec,Canada)were examined statistically by applying different data treatment techniques,through which the most suitable outlier methods were selected for each parameter using multiple decision-making criteria and engineering *** indicated that some methods exhibited better performance in identifying the possible outliers,although several others were unsuccessful because of their limitation in large sample *** well-known boxplot method might not be the best outlier method for most geomechanical parameters because its calculated confidence range was not acceptable according to engineering ***,several approaches,including adjusted boxplot,2MADe,and 2SD,worked very well in the detection of true ***,the statistical tests indicate that the best-fitting probability distribution function for geomechanical intact parameters might not be the normal distribution,unlike what is assumed in most geomechanical ***,the negative effects of schistosity angle on the uniaxial compressive strength(UCS)variabilities were reduced by excluding the samples within a specific angle range where the UCS data present the highest ***,a petrographic analysis was conducted to assess the associated uncertainties such that a logical link was found between the dispersion and the variabilities of hard and soft minerals.

关键词： Intact rock parameters Natural variabilities Outlier detection methods Uncertainties Westwood mine Mineralogy

Phase Transition in a Dense Swarm of Self-Propelled Bots

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Fluid Dynamics & Materials Processing 2024年第8期20卷 1785-1798页

作者： Dmitry Bratsun Kirill Kostarev applied Physics department Perm National Research Polytechnic UniversityPerm614990Russia

Swarms of self-organizing bots are becoming important elements in various technical systems,which include the control of bacterial cyborgs in biomedical applications,technologies for creating new metamaterials with internal structure,self-assembly processes of complex supramolecular structures in disordered media,*** this work,we theoretically study the effect of sudden fluidization of a dense group of bots,each of which is a source of heat and follows a simple algorithm to move in the direction of the gradient of the global temperature *** show that,under certain conditions,an aggregate of self-propelled bots can fluidize,which leads to a second-order phase *** bots’program,which forces them to search for the temperature field maximum,acts as an effective buoyancy *** a consequence,one can observe a sudden macroscopic circulation of bots from the edge of the group to its center and back again,which resembles classical Rayleigh-Benard thermal *** the continuum approximation,we have developed a mathematical model of the phenomenon,which reduces to the equation of a self-gravitating porous disk saturated with an incompressible fluid that generates *** derive governing equations in the Darcy-Boussinesq approximation and formulate a nonlinear boundary value *** exact solution to the linearized problem for infinitesimal perturbations of the base state is obtained,and the critical values of the control parameter for the onset of the bot circulation are *** we apply weakly nonlinear analysis using the method of multiple time *** found that as the number of bots increases,the swarm exhibits increasingly complex patterns of circulation.

关键词： Active matter collective behavior self-organization convection

A low-swelling hydrogel as a multirole sealant for efficient dural defect sealing and prevention of postoperative adhesion

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National Science Review 2024年第6期11卷 294-307页

作者： Xueliang Cheng Zhen Zhang Hui Ren Zheng Zou Yu Zhang Yang Qu Xuesi Chen Jianwu Zhao Chaoliang He CAS Key Laboratory of Polymer Ecomaterials Changchun Institute of Applied ChemistryChinese Academy of Sciences department of Orthopedics The Second Norman Bethune Hospital of Jilin University School of applied Chemistry and Engineering University of Science and Technology of China

Dural defects and subsequent complications, including cerebrospinal fluid（CSF） leakage, are common in both spine surgery and neurosurgery, and existing clinical treatments are still unsatisfactory. In this study, a tissue-adhesive and low-swelling hydrogel sealant comprising gelatin and o-phthalaldehyde（OPA）-terminated 4-armed poly（ethylene glycol）(4aPEG-OPA) is developed via the OPA/amine condensation reaction. The hydrogel shows an adhesive strength of 79.9 ± 12.0 k Pa on porcine casing and a burst pressure of 208.0 ± 38.0 cm H2O. The hydrogel exhibits a low swelling ratio at physiological conditions, avoiding nerve compression in the limited spinal and intracranial spaces. In rat and rabbit models of lumbar and cerebral dural defects, the 4aPEG-OPA/gelatin hydrogel achieves excellent performance in dural defect sealing and preventing CSF leakage. Moreover, local inflammation, epidural fibrosis and postoperative adhesion in the defect areas are markedly reduced. Thus, these findings establish the strong potential of the hydrogel sealant for the effective watertight closure of dural defects.

关键词： hydrogel sealant watertight closure low swelling o-phthalaldehyde chemistry dural sealing

Adaptive State-Dependent Diffusion for Derivative-Free Optimization

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Communications on applied Mathematics and Computation 2024年第2期6卷 1241-1269页

作者： Bjorn Engquist Kui Ren Yunan Yang department of Mathematics and the Oden Institute The University of TexasAustinTX 78712USA department of applied Physics and applied Mathematics Columbia UniversityNew YorkNY10027USA department of Mathematics Cornell UniversityIthacaNY 14853USA

This paper develops and analyzes a stochastic derivative-free optimization strategy.A key feature is the state-dependent adaptive *** prove global convergence in probability with algebraic rate and give the quantitative results in numerical examples.A striking fact is that convergence is achieved without explicit information of the gradient and even without comparing different objective function values as in established methods such as the simplex method and simulated *** can otherwise be compared to annealing with state-dependent temperature.

关键词： Derivative-free optimization Global optimization Adaptive diffusion Stationary distribution Fokker-Planck theory

Suppression and synchronization of chaos in uncertain time-delay physical system

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applied Mathematics(A Journal of Chinese Universities) 2024年第3期39卷 416-437页

作者： Israr Ahmad Muhammad Shafiq department of Preparatory Studies Centre University of Technology and Applied SciencesNizwaOman department of Electrical and Computer Engineering Sultan Qaboos UniversityOman

The mechanical horizontal platform(MHP)system exhibits a rich chaotic *** chaotic MHP system has applications in the earthquake and offshore *** article proposes a robust adaptive continuous control(RACC)*** investigates the control and synchronization of chaos in the uncertain MHP system with time-delay in the presence of unknown state-dependent and time-dependent *** closed-loop system contains most of the nonlinear terms that enhance the complexity of the dynamical system;it improves the efficiency of the *** proposed RACC approach(a)accomplishes faster convergence of the perturbed state variables(synchronization errors)to the desired steady-state,(b)eradicates the effect of unknown state-dependent and time-dependent disturbances,and(c)suppresses undesirable chattering in the feedback control *** paper describes a detailed closed-loop stability analysis based on the Lyapunov-Krasovskii functional theory and Lyapunov stability *** provides parameter adaptation laws that confirm the convergence of the uncertain parameters to some constant *** computer simulation results endorse the theoretical findings and provide a comparative performance.

关键词： chaotic horizontal platform system chaos suppression chaos synchronization robust adaptive control Lyapunov stability theory

Selective nano-buckling improves the performance of graphene logic transistors

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National Science Review 2024年第2期11卷 95-96页

作者： Tong Yang Ming Yang department of applied Physics The Hong Kong Polytechnic University Research Centre for Nanoscience and Nanotechnology The Hong Kong Polytechnic University

The massive integration of silicon-based transistors into modern electronic devices greatly increases power consumption and heat generation/dissipation[1]. In this concern, transistors based on atomically-thin graphene that exhibit high electric and thermoelectric conductivities with negligible contact resistance,

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Unlocking the potential of transdermal drug delivery

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International Journal of Smart and Nano Materials 2024年第3期15卷 432-468页

作者： Shuang Li Jianhao Wu Xiangjun Peng Xi-Qiao Feng Institute of Biomechanics and Medical Engineering Applied Mechanics LaboratoryDepartment of Engineering MechanicsTsinghua UniversityBeijingChina

Transdermal drug delivery(TDD)has gained clinical approval over several decades,with extensive research dedicated to novel drug and device *** notable research progress,the mar-ket adoption of TDD devices has not met anticipated levels,with oral administration and injection remaining predominant delivery *** maximize the potential of TDD,we identify bottlenecks hinder-ing its widespread clinical application and propose promising research *** begin by analyzing stringent demands necessary to truly benefit patients,addressing significant challenges in biomechanics,nanomedicine,and flexible ***,we delve into skin anatomy,enhancement strategies,nano-carriers,and their under-lining mechanisms,highlighting the importance and framework of quantitative *** on these discussions,we highlight the core strength of TDD,such as automatic precise administration based on feedback and high delivery efficiencies,especially applicable to localized conditions(e.g.,central nervous system diseases,tumors).Finally,we envision the future of intelligent TDD device and its opera-tion scenario,aiming to steer research efforts toward faster translation of laboratory innovations into widely used products for sufferers.

关键词： Transdermal drug delivery biomechanics nanomedicine flexible electronics

Securing the Internet of Health Things with Certificateless Anonymous Authentication Scheme

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Computers, Materials & Continua 2024年第8期80卷 2237-2258页

作者： Nisreen Innab department of Computer Science and Information Systems College of Applied SciencesAlMaarefa UniversityRiyadh13713Saudi Arabia

Internet of Health Things(IoHT)is a subset of Internet of Things(IoT)technology that includes interconnected medical devices and sensors used in medical and healthcare information ***,IoHT is susceptible to cybersecurity threats due to its reliance on low-power biomedical devices and the use of open wireless channels for *** this article,we intend to address this shortcoming,and as a result,we propose a new scheme called,the certificateless anonymous authentication(CAA)*** proposed scheme is based on hyperelliptic curve cryptography(HECC),an enhanced variant of elliptic curve cryptography(ECC)that employs a smaller key size of 80 bits as compared to 160 *** proposed scheme is secure against various attacks in both formal and informal security *** formal study makes use of the Real-or-Random(ROR)model.A thorough comparative study of the proposed scheme is conducted for the security and efficiency of the proposed scheme with the relevant existing *** results demonstrate that the proposed scheme not only ensures high security for health-related data but also increases *** proposed scheme’s computation cost is 2.88 ms,and the communication cost is 1440 bits,which shows its better efficiency compared to its counterpart schemes.

关键词： Internet of things internet of health things security authentication hyperelliptic curve cryptography

Hopf bifurcation in a delayed prey-predator model with prey refuge involving fear effect

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International Journal of Biomathematics 2024年第5期17卷 1-32页

作者： Ankit Parwaliya Anuraj Singh Ajay Kumar department of applied Sciences ABV-Indian Institute of Information Technology and ManagementGwalior 474015India

This work investigates a prey-predator model featuring a Holling-type II functional response,in which the fear effect of predation on the prey species,as well as prey refuge,are ***,the model assumes that the growth rate of the prey population decreases as a result of the fear of ***,the detection of the predator by the prey species is subject to a delay known as the fear response delay,which is incorporated into the *** paper establishes the preliminary conditions for the solution of the delayed model,including positivity,boundedness and *** paper discusses the existence and stability of equilibrium points in the *** particular,the paper considers the discrete delay as a bifurcation parameter,demonstrating that the system undergoes Hopf bifurcation at a critical value of the delay *** direction and stability of periodic solutions are determined using central manifold and normal form ***,the global stability of the model is established at axial and positive equilibrium *** extensive numerical simulation is presented to validate the analytical findings,including the continuation of the equilibrium branch for positive equilibrium points.

关键词： Hopf bifurcation fear effect prey refuge periodic solutions time delay branch off