Hasil untuk "Mechanics of engineering. Applied mechanics"

Dongsheng Yang, 杨东升, Kun Xie et al.

Gas–water two-phase flow in porous media is vital in groundwater management and hydrocarbon development, yet most experiments use small cores (5–10 cm) or etched micro-models. These studies often overlook the quantitative characterization of residual gas, long-distance gas–water flow behavior, and effects of gas–water flow on pore structure. This study presents a series of 3 m-long artificial unconsolidated sandstone models with permeabilities of 5, 10, 30, 50, and 100 mD, fabricated via rock–electric testing techniques to simulate edge-water invasion in gas reservoirs. The results indicate that (1) by adjusting clay content, cementing agents, grain size, and sand mix, artificial cores achieve permeability, porosity, cementation strength, sensitivity, and pore structure similar to natural cores; this approach addresses the sampling challenge from unconsolidated sandstone. (2) During long-distance gas–water flow, pressure drops rapidly in the gas–water transition zone. As permeability increases, the zone shifts downstream and becomes narrower. (3) The flow of gas–water causes a large number of particles to gather near the gas–water interface and block the throat, and effective stress on unconsolidated sandstone intensifies this blockage effect. (4) Residual gas exists in the forms of dead-end trapped gas, bypass trapped gas, and snap-off trapped gas. The residual gas volume is mainly controlled by gas saturation and pressure, but the largest amount of residual gas accumulates near the gas–water interface. This study addresses the research gap in understanding long-distance gas–water flow and presents a novel experimental method for unconsolidated porous media.

Mohamad Mokhtari, Saeid Jamei, Zahrapanah Razaviyan et al.

This study investigates the dynamic behavior of a container ship subjected to different Froude numbers and collision angles. The primary focus is on the ship's vertical motion, torsion, roll, and resistance under varying sea conditions. By increasing the Froude number and the ship's speed in calm water, the generated wave height and wave formation resistance significantly increase. The second quarter of the ship encounters the wave bottom at an altitude of 0.065290 meters, followed by a lighter blue hue at an altitude of 0.032864 meters. The vertical motion function at different wave angles (0°, 30°, 60°, 90°, 120°, 150°, 180°) and the total resistance coefficient at various collision angles were analyzed. The findings reveal a substantial increase in dynamic movements and additional resistance due to wave-induced motion as the Froude number rises. The maximum extra resistance occurs when the wave impacts the ship's bow. The calculated conversion functions for torsional and vertical motions closely align with existing laboratory results, demonstrating an error of less than 10%, which is acceptable for numerical simulations. These findings are crucial for understanding and mitigating the challenges faced by ships operating in various sea conditions.

Yingjie Zhao, Jianshu Qin, Shijun Wang et al.

Summary: 2D macromolecules, such as graphene and graphene oxide, possess a rich spectrum of conformational phases. However, their morphological classification has only been discussed by visual inspection, where the physics of deformation and surface contact cannot be resolved. We employ machine learning methods to address this problem by exploring samples generated by molecular simulations. Features such as metric changes, curvature, conformational anisotropy and surface contact are extracted. Unsupervised learning classifies the morphologies into the quasi-flat, folded, crumpled phases and interphases using geometrical and topological labels or the principal features of the 2D energy map. The results are fed into subsequent supervised learning for phase characterization. The performance of data-driven models is improved notably by integrating the physics of geometrical deformation and topological contact. The classification and feature extraction characterize the microstructures of their condensed phases and the molecular processes of adsorption and transport, comprehending the processing-microstructures-performance relation in applications. The bigger picture: Resolving morphological complexity of macromolecules is the stepping stone to the design and fabrication of high-performance, multi-functional materials and to understanding the soft matter behaviors in biology and engineering. To extract the physics of lattice distortion and surface contact beyond the conformation is critical, yet challenging. Here, we show that, by labeling the simulation data using the 2D map of potential energies, the 3D geometry, and the topology of contact, morphological classification can be achieved with high accuracy. The well-trained model can be used to decipher the microstructural complexity using simulation or experimental data, which may include the geometrical representation only. This data-driven approach extracts the key geometrical and topological features of 2D macromolecules that are directly responsible for the material performance in relevant applications and can be extended to study other complex surfaces such as red blood cells and the brain.

Muhammad A. R. Khan, M. Mehedi Hasan Rocky, Md. Ariful Islam et al.

Viscosities (h) of three binary non-aqueous systems of ACN + MEA, + MMEA and + MEEA have been measured in the whole range of compositions at temperatures ranging between 303.15 and 323.15 K at an interval of 5 K. At different compositions, deviations in viscosity (Dh), free energy (ΔG‡) of activation for viscous flow along its excess values (ΔG‡E) were calculated from experimental ρ andh data. For all systems, h vs. x2 initially changed very slowly, but with the increment of solute concentration h were found to rise quite rapidly. The values of Dh were largely positive and they formed a sharp maximum invariably at the highly alkanolamine-rich regions. All positive values of Dh followed the increasing order as: ACN + MMEA > ACN + MEA > ACN + MEEA. The order of DG‡E at the maximum point was ACN + MMEA > ACN + MEA > ACN + MEEA. For the correlative model, zero parameter relations: Bingham, Kendall- Munroe, Gambill, and Eyring relations, one parameter relations: Hind, Grunberg-Nissan, Frenkel, Wijk, Katti-Chaudhri, Tamura Kurata and two as well as three parameter-based models: Heric, Ausländer, McAllister (3-body) and McAllister (4-body) Equation and the Jouyban-Acree model (JA) were employed to correlate viscosities. Ausländer equation fit the best for: ACN + MEA.  McAlliester 4-body fit the best for ACN + MMEA and ACN + MEEA. All the above results were attempted to be interpreted in terms of the strength and order of self-association, intra- as well as intermolecular hydrogen bonding via OH···O or OH···N and the effect due to steric hindrance of the concerned alkanolamine molecules and interstitial accommodation of ACN into alkanolamine network.

Abdul Halim Abdullah, Mitsugu Todo

The prediction of bone remodeling behaviour is a challenging factor in encouraging the long-term stability of hip arthroplasties. The presence of femoral components modifies the biomechanical environment of the bone and alters the bone growth process. Issues of bone loss and gait instability on both limbs are associated with the remodeling process. In this study, finite element analysis with an adaptive bone remodeling algorithm was used to predict the changes in bone mineral density following total hip and resurfacing hip arthroplasty. A three-dimensional model of the pelvis–femur was constructed from computed tomography (CT-based) images of a 79-year-old female patient with hip osteoarthritis. The prosthesis stem of the total hip arthroplasty was modelled with a titanium alloy material, while the femoral head had alumina properties. Meanwhile, resurfacing of the hip implant was completed with a cobalt-chromium material. Contact between the components and bone was designed to be perfectly bonded at the interface. Results indicate that the bone mineral density was modified over five years on all models, including hip osteoarthritis. The changes of BMD were predicted as being high between year zero and year one, especially in the proximal region. Changes were observed to be minimal in the following years. The bone remodeling process was also predicted for the non-operated femur. However, the adaptation was lower compared to the operated limbs. The reduction in bone mineral density suggested the bone loss phenomenon after a few years.

Jing Li, Ranjiangshang Ran, Haihuan Wang et al.

Water shortage not only occurs in arid regions, but also in humid area with little precipitation, despite abundant fog. Authors develop robust and scalable 3D centimetric kirigami structures to control wind flow and regulate the trajectories of incoming fog, yielding high fog collection efficiency.

Punithavathy K., Poobal Sumathi, Ramya M.M.

Lung cancer detection is highly challenging as it is asymptomatic till advanced stage. Early lung cancer detection helps to increase the patient's survival. Computer Aided Diagnosis (CAD) systems have been developed using Machine Learning (ML) and Artificial Intelligence (AI) techniques in detecting malicious regions from medical images. This study is intended to compare the classical ML techniques for lung cancer classification from Positron Emission Tomography/Computed Tomography (PET/CT) images. Significant texture and fractal descriptors extracted from PET/CT images generate non-linear data and were fed as inputs to the classifier. Various hyper-parameters and model parameters for the ML techniques have been tuned to fix optimal parameters for better performance. 10-fold cross validation was used to analyze the performance of the classifiers. Experimental study showed that Support Vector Machine (SVM) with Radial Basis Function (RBF) kernel of width, σ = 1 outperformed and achieved highest accuracy of 98.10%.

Dmitry V. Gorishny

The problem of relationship between events by the example of rail automatic and remote control devices errors is considered. Heuristic synthesis algorithm of dependencies model structure — Bayesian network — according to the diagnostic data on the ground of minimal length description principle is offered. The developed algorithm and its  software implementation are described.

Andrey L. Ozyabkin

A hypothesis of experimental tribothermodynamics had been suggested and proved. The hypothesis permits to define flash temperature on the true contact area as a practical example.

E.A. MAKHNO

The currency exchange regulations carried out by the customs bodies in the given area within the bounds of their competence, and also the control over declaring of particular kinds of goods are discussed. The analysis of the standard-legal base concerning the procedure of the diversion of goods by natural persons is carried out.

Alexander E. Fokin, Maxim D. Gavrilenko, Mikhail P. Shishkarev

The problem on the stipulation conditions for the stationary mode of the drive self-oscillation regime on the basis of the operation analysis of the multiplate adaptive frictional clutch of N. D. Verner’s construction is solved. Its frictional group consists of the disks made from the materials with various friction factor magnitudes.

S.K. Deb Nath

Two elastic plate problems made of duralumin are solved analytically using the displacement potential approach for the case of plane strain and plane stress conditions. Firstly, a one end fixed plate is considered in which the rest of the edges are stiffened and a uniform load is applied to the opposite end of the fixed end. Secondly, a plate is considered in which all of the edges are stiffened and a uniform tension is applied at its both ends. Solutions to both of the problems are presented for the case of plane stress and plane strain conditions. The effects of plane stress and plane strain conditions on the solutions are explained. In the case of stiffening of the edges of the plate, the shape of the plate does not change abruptly, which is clearly observed in both of the cases. For the plane strain condition, the plates become stiffer in the loading direction as compared to the plane stress condition. For the plane strain condition, there is a significant variation of the normal stress component, σ zz at different sections of the plate. The graphical results, clearly identify the critical regions of the plate for the case of the plane stress and plane strain condition.

Frydrýšek Karel, Jančo Roland

This article deals with a simple planar and statically determinate pin-connected truss. It demonstrates the processes and methods of derivations and solutions according to 1st and 2nd order theories. The article applies linear and nonlinear approaches and their simplifications via a Maclaurin series. Programming connected with the stochastic Simulation-Based Reliability Method (i.e. the direct Monte Carlo approach) is used to conduct a probabilistic reliability assessment (i.e. a calculation of the probability that plastic deformation will occur in members of the truss).

Petrović Milan M., Stevanović Vladimir D.

A model of two-component two-phase critical flow is presented. The modelling approach is based on one-dimensional homogeneous gas-liquid two-phase isentropic flow of mixture. The homogeneous model is modified by taking into account the void fraction and two-phase mixture density dependence on velocity slip. The velocity slip is calculated using Chisholm correlation that depends on the gas phase quality and Zivi correlation for the prediction of the maximum velocity slip values. At the location of the critical flow the two-phase mixture velocity equals sonic velocity and it is calculated with the so-called ''frozen sonic velocity' model. The model is validated against data measured in air water flow at the PUMA experimental facility. Obtained results are presented together with the predictions by the well-known Fauske model. It is shown that Fauske model overpredicts measured critical mass fluxes, while the present model shows acceptable agreement with the measured data.

M. Irani, F. Khamchinmoghadam

Introduction: The hydrological models are very important tools for planning and management of water resources. These models can be used for identifying basin and nature problems and choosing various managements. Precipitation is based on these models. Calculations of rainfall would be affected by displacement and region factor such as topography, etc. Estimating areal rainfall is one of the basic needs in meteorological, water resources and others studies. There are various methods for the estimation of rainfall, which can be evaluated by using statistical data and mathematical terms. In hydrological analysis, areal rainfall is so important because of displacement of precipitation. Estimating areal rainfall is divided to three methods: 1- graphical. 2-topographical. 3-numerical. This paper represented calculating mean precipitation (daily, monthly and annual) using Galerkin’s method (numerical method) and it was compared with other methods such as kriging, IDW, Thiessen and arithmetic mean. In this study, there were 42 actual gauges and thirteen dummies in Mashhad plain basin which is calculated by Galerkin’s method. The method included the use of interpolation functions, allowing an accurate representation of shape and relief of catchment with numerical integration performed by Gaussian quadrature and represented the allocation of weights to stations. Materials and Methods:The estimation of areal rainfall (daily, monthly,…) is the basic need for meteorological project. In this field ,there are various methods that one of them is finite element method. Present study aimed to estimate areal rainfall with a 16-year period (1997-2012) by using Galerkin method ( finite element) in Mashhad plain basin for 42 station. Therefore, it was compared with other usual methods such as arithmetic mean, Thiessen, Kriging and IDW. The analysis of Thiessen, Kriging and IDW were in ArcGIS10.0 software environment and finite element analysis did by using of Matlab7.08 software environment. The finite element method is a numerical procedure for obtaining solutions to many of the problems encountered in engineering analysis. First, it utilizes discrete elements to obtain the joint displacements and member forces of a structural framework and estimate areal precipitation. Second, it uses the continuum elements to obtain approximate solutions to heat transfer, fluid mechanics, and solid mechanics problems. Galerkin’s method is used to develop the finite element equations for the field problems. It uses the same functions for Ni(x) that was used in the approximating equations. This approach is the basis of finite element method for problems involving first-derivative terms. This method yields the same result as the variational method when applied to differential equations that are self-adjoints. Galerkin’s method is almost simple and eliminates bias by representing the relief by suitable mathematical model and incorporating this into the integration. In this paper, two powerful techniques were introduced which was applied in Galerkin’s method: The use of interpolation functions to transform the shape of the element to a perfect square. The use of Gaussian quadrature to calculate rainfall depth numerically . In this study, Mashhad plain is divided to 40 elements which are quadrilateral. In each element, the rain gauge was situated on the node of the stations. The coordinates are given according to UTM, where x and y are the horizontal and z, the vertical (altitude) coordinate. It was necessary at the outset to number the corner nodes in a set manner and for the purpose of this paper, an anticlockwise convention was adopted. Results and Discussion: This paper represented the estimation of mean precipitation (daily, monthly and annual) in Mashhad plain by Galerkin’s method which was compared with arithmetic mean, Thiessen, kriging and IDW. The values of Galerkin’s method by Matlab7.08 software and Thiessen, kriging and IDW by ArcGIS10.0 were calculated. The base of the comparison was isohyetal method, because it showed the relief and took into account the effect of rain gauges, therefore it could represent rainfall data and region condition completely. The most accurate method was isohyetal method in estimating mean precipitation. Cross-validation was usually used to compare the accuracy of interpolation method. In this study, root mean square error (RMSE) was used as validation criteria. Meanwhile, in the present study, the effects of altitude were neglected for two reasons. First, partial correlation coefficient of rainfall/altitude gradients was weak and second, the storms data were not accessible. Conclusions: In this study, the estimation of areal rainfall by Galerkin’s method was an innovative step. The case study was Mashhad basin (9909 km2) which included 42 rain gauges. Comparing other methods indicated that: Galerkin’s method was more efficient in comparison with arithmetic mean and it had more accurate results. Result of Galerkin’s method was similar to Kriging, IDW and Thiessen method. Unlike other methods, mesh of finite element could be used for calculating runoff, sediment and temperature and it did not need station weights. Even within one network the number of interpolation points can be varied, so that in a rugged region the number can be increased with little increase in effort, while in a more uniform region fewer are necessary.

S. Oterkus, E. Madenci

A rod or beam is one of the most widely used members in engineering construction. Such members must be properly designed to resist the applied loads. When subjected to antiplane (longitudinal) shear and torsional loading, homogeneous, isotropic, and elastic materials are governed by the Laplace equation in two dimensions under the assumptions of classical continuum mechanics, and are considerably easier to solve than their three-dimensional counterparts. However, when using the finite element method in conjunction with linear elastic fracture mechanics, crack nucleation and its growth still pose computational challenges, even under such simple loading conditions. This difficulty is mainly due to the mathematical structure of its governing equations, which are based on the local classical continuum theory. However, the nonlocal peridynamic theory is free of these challenges because its governing equations do not contain any spatial derivatives of the displacement components, and thus are valid everywhere in the material. This study presents the peridynamic equation of motion for antiplane shear and torsional deformations, as well as the peridynamic material parameters. After establishing the validity of this equation, solutions for specific components that are weakened by deep edge cracks and internal cracks are presented.

A. Weinmann, M. Storath

Chien-Hung Liu

The 275 papers are grouped as follows: Chapter 1: Materials Processing Technologies and Analysis, Materials Engineering Chapter 2: Advanced Design for Thermal and Mechanical Engineering Chapter 3: Development and Technologies in Electrical and Electronic Engineering, Communication and Power Engineering Applications Chapter 4: Control and Automation Technology, Mechatronics, Robotics for Manufacture and Industry Chapter 5: Advanced Development for Information Technologies and Engineering, Networks and Software Applications, Data Acquisition and Processing, Intelligent Systems Chapter 6: Modern Design for Green and Environmental Technologies, Energy-Saving Technologies, Structural and Civil Engineering, Applied Mechanics Applications Chapter 7: Contemporary Development for Optical Engineering, Image Processing, Quality and Analysis, Measurement, Instrumentation and Detection Technologies Chapter 8: Innovation in Management and Design, Related Topics.

F. Streller, G. E. Wabiszewski, F. Mangolini et al.

Renato Machado Cotta, D. Knupp, C. Naveira-Cotta et al.