Journal of Modern Mechanical Engineering and Technology
Journal of Modern Mechanical Engineering and Technology is a refereed journal dedicated to the publication of high-quality papers providing the latest and outstanding information in all areas of Mechanical Engineering. It provides the authoritative settings for researchers and scholars worldwide to promote, share, and discuss various new issues and developments in different areas of Mechanical Engineering.
Mixed Mode Fracture Mechanics and Crack Growth Analysis in Steam Turbine Discs for Remaining Life Assessment under Thermal Stresses and Mechanical Loading
The long‑term performance and structural integrity of steam‑turbine discs are strongly influenced by crack‑growth behavior under combined thermal stresses and mechanical loading. In this study, a comprehensive analytical framework based on finite element analysis (FEA), mixed‑mode fracture‑mechanics evaluation (Modes I, II, and III), and fatigue crack‑growth modeling using the Paris law is presented. The results indicate that Mode II plays the dominant role in the stress‑intensity distribution and crack‑growth behavior of the investigated turbine disc, while Modes I and III also contribute and cannot be neglected. Therefore, safety assessment based solely on Mode I analysis may lead to inaccurate evaluations of structural integrity. The calculated effective stress‑intensity factor was compared with the fracture toughness of 12Cr steel, showing that the turbine disc currently operates within a safe margin against instantaneous fracture; however, gradual fatigue crack growth under thermo‑mechanical loading conditions remains possible. The crack‑growth analysis further demonstrates that a significant portion of the fatigue life is spent during the stable slow‑growth phase as the crack propagates from small initial sizes to intermediate lengths. The proposed fracture‑mechanics‑based approach provides a reliable tool for condition monitoring, inspection planning, and remaining‑life assessment of steam‑turbine discs, thereby contributing to improved operational safety and maintenance decision‑making.
Numerical Investigation of the Effects of Tool Geometry on Multi-Point Forming Process
Metal forming is an essential technique for manufacturing of lightweight components that offer enhanced energy efficiency, functionality, and sustainability. This study presents a comprehensive numerical investigation into the influence of forming tool geometry on the quality and performance of the multi-point forming (MPF) process. Finite element simulations were employed to systematically evaluate the effects of geometric tool design variables, namely, tip geometry, shank configuration, and tip structure (solid or hollow) on the predicted forming performance responses, namely, wrinkling behavior, springback displacement, and thickness variation. The numerical results show that the parabolic and elliptical tip geometries prove superior forming performance by effectively suppressing wrinkling and minimizing springback while hemispherical and spherical tips result in increased wrinkling susceptibility and higher residual elastic stresses. Moreover, the inclined shank configuration leads to higher wrinkling and springback compared to other shank configurations. Solid tip structures induce higher wrinkling levels and springback compared to hollow tips. In addition, thickness uniformity is markedly improved when smooth tool profiles such as flat-end, elliptical, and rounded hemispherical geometries are employed. In contrast, the combined use of a hemispherical tip with a square section and an inclined shank results in the most pronounced thickness variation. Furthermore, solid tip designs generally promote a more uniform thickness distribution across the blank, whereas hollow tips exhibit a greater tendency toward localized thinning. Ultimately, the optimal MPF tool configuration consists of a parabolic or elliptical tip geometry combined with a hollow tip and a straight shank configuration, as it presents the best compromise for minimizing wrinkling and springback while maintaining acceptable thickness distribution.
Copyright (c) 2026 Journal of Modern Mechanical Engineering and Technology
Magnesium Reagents in the Synthesis of Magnesium Self-Lubricating Coatings
The results of studies of friction and wear of detonation composite coatings based on ternary magnesium boride under constant load over a range of sliding speeds are presented. Their structural and phase composition and the complex of surface oxide structures were determined using modern physical analysis methods. It has been established that the minimization of wear intensity and friction coefficients is due to the formation of a set of surface structures capable of regenerating a stable self-lubricating structured layer under friction conditions due to the ternary additive interaction of carbide graphite, complex oxide structures, and active aluminum- magnesium-boron compounds. Factors influencing the formation and maintenance of the dynamic level of the self-lubricating layer have been identified as a multiscale surface interaction phenomenon with an effective capacity for self-renewal and self-regulation. At the same time, the continuous protective layer of surface structures shields the adhesive-molecular interaction of contact combinations and blocks the development of unacceptable failure processes.
CFD Analysis on the Dynamic Behaviour of Pivot Point for a KCS During Ship Turning Manoeuvre in Waves
A comprehensive grasp of vessel manoeuvring characteristics is indispensable for ensuring precise handling and maritime safety. In practice, for Masters and Pilots, an intuitive understanding of the ship's rotational centre—the pivot point—is often more critical than merely fulfilling performance metrics. This study systematically investigated the dynamic migration of the pivot point for a KCS vessel under various wave conditions (initial direction, length, and height), addressing a topic relatively overlooked in conventional manoeuvring studies. The research methodology employed a high-fidelity URANS approach combined with a dynamic overset grid method to simulate 6-DOF turning circle manoeuvres. Through numerical analysis, stable pivot point behaviour under general sea conditions was confirmed, while non-linear and abrupt positional shifts under critical threshold conditions were quantitatively identified. Notably, the results numerically demonstrated that the pivot point migrated sharply beyond the bow boundary under extreme wave heights or when encountering short waves in quartering sea. This finding confirms that the pivot point is dynamically repositioned by changes in hydrodynamic moments driven by sway and yaw motions. These findings serve as a practical reference for operators to pre-emptively recognize and respond to changes in rudder effectiveness and turning moments when manoeuvring in adverse weather conditions.
Study of the Possibility of Increasing the Survivability of Quadcopters Under External Influences
When operating quadcopters (QC), situations arise such as unauthorized intersections of flight paths with flocks of birds and aircraft, physical obstacles along the flight path, and areas with elevated electromagnetic fields. These situations can lead to the QC's destruction. To increase the QC's survivability in such situations, an additional propulsion system (APS) can be installed, allowing for rapid changes in trajectory and flight coordinates. The difficulty in implementing this design solution lies in synchronizing the operation of the main and auxiliary engines. To address this issue, research was conducted and a control system (CS) was developed that synchronizes the engines when the APS is activated, quickly removing the QC from the zone of adverse external influences and maintaining controllability during the rest of the flight.
An Optimum Design for Laminated Steel Leaf Springs
This study presents an optimum design methodology for laminated semi-elliptic steel leaf springs used in vehicle suspension systems, with the primary objective of minimizing spring weight while satisfying structural, geometric, and dynamic requirements. Analytical expressions for bending stress, mid-span deflection, stiffness, and natural frequency are derived based on classical beam theory and expressed in non-dimensional form to enable a generalized and systematic optimization framework. The design variables considered include strip thickness, strip width, and number of leaves, while constraints are imposed on allowable bending stress, maximum deflection, bounded geometry, and natural frequency to ensure structural safety and acceptable ride comfort. The resulting nonlinear optimization problem is solved using MATLAB for a carbon steel (AISI 1020) leaf spring subjected to a specified vertical load. The optimized design consists of four steel strips with a width of approximately 75 mm and a thickness of about 7.5 mm, yielding a total spring weight of approximately 19 kg. The results demonstrate that significant weight reduction can be achieved without compromising stress limits, deflection requirements, or dynamic performance. The proposed methodology provides a reliable and efficient tool for the optimal design of steel laminated leaf springs and can be extended to other materials, loading conditions, and vehicle applications. The results obtained from this study have been compared with available numerical results obtained by FEA and a good agreement is aobtained.
Thermal Fluid and Chemical Analysis of Ionized Air Test Injection for Cold Start Emission Mitigation
The cold start period of an internal combustion engine (ICE) is a dominant source of hydrocarbon (HC) and carbon monoxide (CO) emissions. This paper analyzes an innovative ejector system for distributing ionized air directly into the exhaust system to accelerate pollutant oxidation. Analytical results demonstrate that the system achieves an ejection ratio ω = 0.187 at an exhaust temperature of 450 K, while a 180 W heater provides the necessary thermal compensation to maintain the mixture temperature above the 380 K activation threshold. Experimental validation confirmed that ionized air initiates low-temperature oxidation (afterburning), evidenced by a 5.0% vol. increase in CO2 concentration. This synergistic fluid-thermal and chemical strategy reduces the catalyst’s critical inactivity period from 120 s to 85 s, offering highly efficient method for meeting stringent emission regulations.
Copyright (c) 2025 Journal of Modern Mechanical Engineering and Technology
Triboresistance of Composite Nanocoatings Based on Magnesium Compounds at Elevated Temperatures
The results of the study of the wear characteristics of detonation composite nanocoatings based on magnesium orthosilicate under conditions of high-temperature friction under constant load in the field of sliding speeds, on the surface of which stable antifriction structures are formed under conditions of elevated temperatures, are presented. The structural-phase composition of the coatings was determined by methods of modern physical analysis and the complex of high-temperature compounds of the surface layers was determined. The developed and studied coatings have high and stable antifriction properties. It was determined that the antifriction property under friction loading is due to the self-ordering of surface high-temperature oxide and oxygen-free structures, which are characterized by low shear resistance and work as solid lubricants that modify the contact surfaces and prevent damage to moving joints.
Mechanical Characterization of Natural and Synthetic Fibres using Sandwich Structures Under Bending
Fibre-reinforced sandwich panels are a well stablished design solution for applications that require high stiffness and low weight, but the high cost and enviromental impact of synthetic fibres have prompted the research for sustainable alternatives, such as natural fibres. While they offer potential for cost reduction and environmental sustaintalibity, their mechanical properties may compromise structural reliability. In this context, this work compares the equivalent stiffness of different composite sandwich panels under bending, using carbon, glass, linen, jute and cotton fibres as reinforcement. The specimens were produced using the Vacuum Assisted Resin Transfer Moulding (VARTM) and tested under four point bending conditions. Analytical methods were used for mechanical characterization, followed by Finite Element Method (FEM) validation. The results show that carbon fibre yields a greater stiffness-to-weight ratios followed by glass, jute, linen and cotton fibres. Sandwich panels with natural fibres reinforcement showed relative bending performances ranging from 19% to 35% of the carbon fibre ones.
A Statistical Methodology of Cyclic Plasticity Inhomogeneity at Grain Scale
The inhomogeneous plastic deformation has important effects on the manufacturing process and the fatigue property of mechanical products. To directly and correctly evaluate the deformation inhomogeneity of grain scale under cyclic loading, a statistical method is proposed and named as the normalized standard deviation. The method is comprised of the following steps: (1) Construct a representative volume element (RVE) of polycrystalline by Voronoi tessellation and electron backscatter diffraction, and calculate the grain strain by a constitutive model of crystal cyclical plasticity. (2) Deal with grain strain data of RVE by Min-max normalization method. (3) Compute the standard deviation of the normalized data as the identification of mesoscopic inhomogeneity. In order to validate the proposed normalized standard deviation, the contrastive analyses with the strain contours, the weighted standard deviation and the coefficient of variation are conducted at the same conditions of cyclic loading. The results demonstrated that the normalized standard deviation was the best as the indication of cyclic plasticity inhomogeneity among the above methods.
Single-Layer 79 GHz Microstrip Patch Array for All-Weather Automotive Radar
Advanced driver-assistance systems (ADAS) demand radar sensors that combine centimetre-level resolution, wide angular coverage, and all-weather reliability, yet must fit behind a plastic bumper at automotive cost. This study meets that challenge with a fully self-contained 79 GHz front-end fabricated on a single-layer RO3003 printed-circuit board. Closed-form cavity models, applied from first principles, yield patch dimensions without iterative tuning. Sixteen patches arranged in a 4 × 4 half-wavelength array deliver 16 dBi broadside gain, 3.2 GHz (−10 dB) impedance bandwidth, and a 33° half-power beam-width, thereby covering the entire 76–81 GHz allocation. Solving the radar-range equation shows that even under 8 dB km⁻¹ heavy-rain attenuation the sedan detection limit contracts by only 2 m (51 m → 49 m), while motorcycle and pedestrian ranges are virtually unaffected. To our knowledge, this is the first single-layer PCB radar front-end to achieve such performance without empirical tuning, and it offers a clear upgrade path toward imaging radar and highway ACC.
Application of Wave Technologies for the Preparation of Fuels Containing Organic Waste Pyrolysis Products
Products of fast pyrolysis of organic materials (bio-oil) have such advantages as ease of storage and transportation, production from renewable raw materials, but have not yet found wide application as motor and boiler fuels. The article describes the results of research aimed at obtaining such fuel containing petroleum fuel oil and bio-oil as the main components. Direct mixing of these components is a difficult task due to their chemical incompatibility. Its solution required the development of technology and devices, which was the purpose of the presented research results. The research methodology was based on mathematical modeling of the processes of mixing fuel components, analysis of its results, their transfer to natural samples and their experimental study. As a result, a technology and design of mixers were developed that made it possible to obtain a stable mixed fuel containing fuel oil and bio-oil in the following proportions of the mass ratio up to 50:50. The obtained results confirmed the correctness of the chosen approach, which made it possible to develop new technology and equipment to achieve the stated research goal.
Wear Resistance of Amorphous-Crystalline Coatings Under Boundary Friction
The results of tests under boundary friction conditions are present detonation coatings Zr-Al-B in a wide range of changes in friction conditions. The obtained results were compared with the parallel tested coatings based on tungsten carbide type WK-15, also with samples of 30HGSNA steel and BrOCS6-6-3 bronze. The qualitative and quantitative composition of surface layers participating in boundary friction conditions was assessed using modern physical methods of analysis. Profilograms and microphotographs of friction surfaces of amorphous-crystalline coatings are presented, showing that under boundary friction conditions, coating samples are smoothed, which leads to a decrease in roughness. Installed the presence of the formation of solid solutions of oxygen interstitialization in zirconium, which corresponds to the formation of secondary structures of the first type on friction surfaces, the characteristic feature of which is their surface localization, ultra-dispersed structure, the ability to minimize destruction and screen unacceptable adhesive phenomena. Using Auger electron microscopy, it was confirmed that oxygen completely replaces sulfur in surface structures. It is shown that the studied detonation coatings Zr-Al-B, developed for practice, have high tribotechnical characteristics in the entire range of tests under boundary friction conditions. At the same time, as a result of studies of the mechanism of tribochemical transformations of hydrocarbons and the properties of transformed surface films, it was established that they retain lubricating properties and provide high antifriction characteristics of the friction system in the entire wide range of changes in boundary friction conditions.
Self-Organization of Surface Structures during Friction Coatings Based on Forsterite
In the work, the patterns of friction and wear of forsterite-based coatings were studied, and their structural-phase composition, conditions of formation and self-regulation of surface structures were determined from the standpoint of the structural-energy theory of friction. Detonation coatings developed on the basis of forsterite are characterized by high anti-friction properties. The conducted studies showed that the most appropriate application of the investigated coatings is to increase the reliability of operation of friction nodes during strengthening and restoration, for example, for moving pairs of control mechanisms, hinges of guide surfaces, cams, sliding supports, pairs with reciprocating movement, bearings, sliding guides, etc. in which the use of traditional lubricants is undesirable. Compounds of complex oxides of magnesium orthosilicate were used as the basis of composite coatings. The structural and phase composition of the coatings, the peculiarities of the formation of complex alloyed secondary structures, taking into account both the properties of the alloying elements and the structures formed by them, were established. The physical mechanism was determined and the main factors determining the level of thermodynamic graphitization were clarified. The studied self-lubricating compositions can be used both for strengthening and for high-quality restoration of worn triboelements by any technological methods using powder materials.
Development of Control Method for Abration and Evaluation of Electrocautery Device Controller
The symmetrical impedance bridge, will be suggested to yield consistent and reliable results for measuring tissue damage during electrosurgical ablation. The methods that were identified as potentially viable for ablation detection were force and displacement measurements between the electrode tip and tissue surface. These were found to correlate tissue damage due to a high degree of variability in charge density caused by contact area variation. Another method, temperature measurement via thermistors, will be found to have a response time and a non-contact method will be examined with the size constraints. The last method will be to measure and correlate changes in the power output of the ESU to tissue damage. This method will be practically examined to measure and correlate to tissue damage due to ESU power output modulation. The changes in the tissue's electrical properties can be measured directly far more easily than measuring the power output. Correlation with tissue damage tended to be strong with an error range below what can be detectable by the human eye. But the high degree of variability in the mechanical properties of tissue makes the use of force and displacement measurements difficult to implement as part of a control method for ablation control.
The Correlation Between Wear and Lubricating Film Thickness in the Tribocorrosion of CoCrMo Alloy
Tribocorrosion modelling of passive metals considering the lubrication effect from solution is still not well studied. A lubricated tribocorrosion model for CoCrMo alloy metal-on-metal hip joints has been developed, while the generalization of this model is restricted by Dowson’s empirical correlation. This study explored the correlation between wear of CoCrMo alloy in tribocorrosion and lubricating film thickness. The results showed that the chemical, mechanical and total wear volumes of CoCrMo alloy in tribocorrosion were significantly influenced by the lubrication effect from the solution. Good correlations were obtained between the lubricating film thickness and chemical, mechanical and total wear, respectively. The new chemical and mechanical wear correlations could be used to generalize the current lubricated tribocorrosion model for CoCrMo alloy.
Effective Technologies for Finishing and Cleaning Processing: Innovations Based on Screw Rotors
The results of many years of scientific research in the development of machines, installations, and devices for finishing and cleaning processing of machine parts are presented. Typical diagrams of machines based on screw rotors of classes I-IV are included, along with the types of finishing and cleaning operations performed by screw rotors, requirements for the parts being processed, the processing environments, and the composition of solutions used in the finishing and cleaning of components. Additionally, the methodology and calculations for a continuous operation setup designed for finishing and cleaning parts with specified productivity are demonstrated.
Finishing and cleaning processing of parts
Numerical Simulation of the Multi-Roller Skew Tandem Rolling of Unequal Wall Thickness Hollow Stepped Shafts
This paper proposes a multi-roll skew rolling forming process to address the slow forming speed of large-section shrinkage for aviation turbine shafts. Using Simufact Forming software, simulations were conducted on the GH4169 turbine shaft blank, analyzing the variations in stress, strain, and temperature fields during the forming process of a hollow shaft component with an initial wall thickness of 6mm. Additionally, we further explored the intrinsic relationship between the initial wall thickness and the depth of the concave center at the end of the workpiece. The results indicate that after multi-field coupling effects, the metal deformation of the workpiece gradually accumulates along the axial direction, reaching a peak after achieving the maximum reduction, while displaying a trend of decreasing from the outside to the inside. Additionally, there is a positive correlation between the depth of the concave center at the end of the workpiece and the initial wall thickness; as the amount of metal involved in the deformation increases, the depth of the concave center also intensifies. These findings provide an important theoretical basis for achieving flexible rolling formation of turbine shafts.
Application of Anal Manometry in the Planning for Anal Fistula Surgery
Anal fistula does not heal spontaneously without surgery, and anal function should be preserved after muscle dissection, which is a challenge even to the most experienced surgeon. In order to develop a planner for anal fistula surgery, anal manometry used in the measurement of pressures in the anal canal to investigate the anal function is reviewed. In this review paper, current techniques are described and compared with each other, and technical and clinical challenges are discussed. There are four types of catheters used to measure anal sphincter pressure: water-perfused, solid-state, air-coupled, and fiber optic catheter. Parameters acquired by anal manometry and their relationship with fecal incontinence after anal fistula surgery are discussed. Vectormanometry can provide the pressure profile along the anal canal in three dimensional space, pressure vectorgram, and cross-sectional radial asymmetry, which have more advantages than the conventional method. Understanding the technology and development of anal manometry is critical for the anal fistula surgical planning. A novel design is highly desired for 3D pressure profile measurement along the entire anal canal simultaneously without pulling the catheter.
Experimental Investigation of Oil Film Variation in Finite Line Contact Under Intermittent Motion
The variation of oil film distribution in the line contact area of pin and disk was experimentally observed during a periodic intermittent motion. The study was conducted on a ball-disk optical interferometric test rig, with motion speed controlled by PLC programming. PAO40 oil was primarily used in the experiment, with the glass disk undergoing periodic motion of constant speed-deceleration-stop-acceleration, while the pin roller remained fixed. The results indicate that when the motion stops, a portion of the oil is entrapped in the center of the contact area. As the acceleration phase begins, this portion of the oil is gradually squeezed out of the contact area, and the oil film with lowest thickness at the entrance of the contact area moves towards the exit of the contact area, passing through the contact center. It can also be observed that during the entire process, an increase in speed increases the film thickness, while an increase in deceleration time, i.e., a decrease in deceleration, reduces the film thickness during the stop phase.
A Flow Structure Interaction Method for Towed Cable System
Abstract: The ocean towed cable system is a classic example of fluid-structure interaction (FSI). This interaction can exhibit stability or oscillation between a highly deformable moving cable and the surrounding turbulent flow. However, in dynamic simulations of towed cable systems, a constant drag coefficient for an infinite circular cylinder is often used based on experimental data. An innovative fluid-structure interaction method is introduced to obtain accurate drag distribution along cable to couple with towed system dynamics. A modified nodal position finite element method (NPFEM) coupled with Reynolds-averaged Navier-Stokes (RANS) approach has been utilized to predict hydrodynamic forces along the cable. A data exchange algorithm has been developed specifically for fluid-structure interaction within the towed cable system where the cable profile is transferred to construct the flow domain while hydrodynamics is interpolated for NPFEM analysis. A topology partition around cable is applied. A multiblock grid is generated around cable. The simulation results of the fluid-structure interaction of the towing system are verified. This FSI scheme reveals how strongly hydrodynamics determine cable dynamics and induce vortex structure vibrations around a towed cable system. Parametrically controlled structured grid generation and their applicability for complex flow fields have also been discussed. Detailed descriptions of boundary layer separation evolution around spatially distributed cable are provided. This FSI scheme reveals a real strongly hydrodynamic determined cable dynamics and vortex structure induced vibrations around a towed cable system. The proposed method enhances predictive accuracy of the towed system dynamics response.
Reynolds Averaged Navier Stokes Equations
Remarks on Solving Methods of Nonlinear Equations
Abstract: In the field of mechanical engineering, many practical problems can be converted into nonlinear problems, such as the meshing problem of mechanical transmission. So the solution of nonlinear equations has important theoretical research and practical application significance. Whether the traditional Newton iteration method or the intelligent optimization algorithm after the popularization of computers, both them have been greatly enriched and developed through the continuous in-depth research of scholars at home and abroad, and a series of improved algorithms have emerged. This paper mainly reviews the research status of solving nonlinear equations from two aspects of traditional iterative method and intelligent optimization algorithm, systematically reviews the research achievements of domestic and foreign scholars, and puts forward prospects for future research directions.
Vibro-Acoustic Analysis of an Underwater Cylindrical Shell with Internal Structures and a Comparison with Experiment
Abstract: In this work, the low-frequency vibration response and full-band acoustic radiation characteristics of an underwater reinforced cylindrical shell with internal structures are studied by combining the FEM with SEA. The stiffened cylindrical shell contains internal structures such as the F-shape plates and the support valve frames. The exciting sources have two different exciting forces corresponding to two experimental conditions. In the low-frequency band, the FEM was employed, and in the medium and high-frequency bands, the SEA was used. A comparison of the numerical results and the experiment shows that they agree well. The FEM and SEA give better results at [1,1k] Hz and [1k,10k] Hz, respectively. Due to mesh quality limitations, the FEM is not favorable for medium and high-frequency calculations. The SEA focuses on the structural mean power flow but cannot obtain position-specific vibrational responses. The results show that the internal excitation source mainly causes the structural vibration and sound radiation and are closely related to the free vibration characteristics of the structure. In addition, with the increase in frequency, the circumferential sound pressure level of the underwater structure has more substantial directivity.
Abstract: Design solutions are presented for the implementation of working chambers in the form of relative toroidal screw drums, intended for the finishing treatment of components in the conditions of rotary-screw technological systems.
Mathematical Model of Anal Canal for Anal Fistula Surgery
Abstract: Purpose: Surgery is necessary for the treatment of an anal fistula. However, excision of some sphincter muscle would compromise sphincter integrity or function, which is the cause of a reduced success rate in the long term. In order to develop an appropriate surgical plan, a mathematical model that describes the relationship between the internal pressure of the anal canal and the structure of anal sphincters is required. Methods: The anatomical structure of the anal canal and the corresponding sphincter pressure can be measured by endoanal ultrasound (EAUS) imaging and manometry, respectively. Length-tension relationships for skeletal and smooth muscles, two major components of the external and internal anal sphincter, respectively, were reviewed first. Results: Based on the information about the internal and external sphincters, two mathematical models, the thick-wall cylinder model and the two-layer model, have been created, from which the influence of complete or partial excision of the sphincter muscle can be estimated. Conclusions: The proposed thick-wall cylinder and two-layer models could describe the relationship between the internal anal canal pressure and the structure of anal sphincters, from which the influence of complete or partial excision of the sphincter muscle may be estimated.
A High Precison Phase Extraction Algorithm from a Single Shot Interferogram
Abstract. Phase shifting interferometry is an optical metrology with a high precision, but it usually requires the expensive high precision phase shifter. Therefore, low cost methods of extracting phase from a single shot interferogram were very valuable, but available algorithms are usually effective only in a limited conditions. To solve these problems, a novel method is presented in this work. Based on this method, the interference fringe is retrieved to a wrapped phase and divided into different regions and the index of the pixel is calculated. The pixels in the same region have the same parity and the PSF’s gravity center of part wavefront so as to solve the sign ambiguity. The theoretical simulation results indicate that the PV of wavefront error is 0.00054λ and the rms is 0.000125λ,which is much better than the results from the Fast Fourier Transformation method. The experimentally measured interferogram is also used to validate the method. It has the advantages of simplicity, high precision and effective for both open and closed interferometer fringes.
Improving the Antifriction Behaviors of Steel by Hybrid Treatments of MoS2 and Surface Texture
Abstract: In the present paper, the composite coatings with MoS2 and graphite in the epoxy resin were deposited on the textured surface of steel by laser and wire-electrode cutting technology to improve the anti-friction behaviors of the steel. The influences of the content of MoS2 and graphite and the types of surface texture on the anti-friction behavior were studied systematically. The experimental results show that the textured specimens with 1 mm space line and pentagon shape pore exhibit low friction behaviors under dry friction. CoF (coefficient of friction) of the pore and line textured with high content of MoS2 and graphite is reduced by 27.7% and 42.3% under dry friction and by 30.0% and 33.3% under starved lubrication, respectively. CoF of the texture and coating duplex-treated steel is much lower than that of the untreated steel due to the solid lubrication of MoS2 and graphite under dry friction. The possible antifriction and antiwear mechanism is discussed. It is concluded that the duplex-treated steel with the texture and coating exhibits good anti-friction behaviors and the composite coatings with solid lubricant are beneficial to improve the tribological properties of steel under starved and dry friction testing conditions. It is shown that hybrid surface treatment with the texture and solid lubricant coating is an effective way to improve the tribological properties of steel. Solid lubricant coatings deposited on the textured surface can be applied to improve the antifriction behaviors of steel under starved lubrication and dry friction.
Effect of Turning Angles on the Inflow Characteristics in a Waterjet Propulsion Pump
Abstract: To study the influence of turning maneuvering navigation angle on the inflow characteristics of water jet propulsion pumps, numerical simulations were conducted on mixed flow water jet propulsion pumps under straight and left and right 15 °/30 ° turning navigation states. By comparing the hydraulic performance differences of water jet propulsion pumps under five navigation states, the intrinsic relationship between turning angle and pump inflow morphology was elucidated, and the evolution mechanism of pump inflow morphology under straight navigation and turning conditions was emphasized, and conduct quantitative analysis on the inflow quality. The research results of this article provide a theoretical basis for selecting appropriate operating angles for ships under turning maneuvers.
Vehicle Longitudinal Control with the Sliding Mode Method Considering Uncertainty of the Model
Abstract: In this paper, the control algorithm for longitudinal control of a passenger car that is moving on the highway and urban traffic is provided. Longitudinal dynamic equation including resisting forces acting on the vehicle presented and structural and non-structural uncertainties in the model are investigated. To control the speed of vehicles on the highway and vehicle distance control in city traffic, vehicle longitudinal control laws have been proposed. To control the speed of vehicles on the highway and in city traffic, vehicle longitudinal control laws have been proposed. In order to control the nonlinear systems, the sliding mode method which is a robust control method has been used for the design controller. The controller consists of two algorithms as speed control and distance control that their duty is done with the force generation to move the vehicle and overcome the disturbances and uncertainties using tracing of it by car. Finally, to ensure the ability of control and efficiency under different conditions, the control rules are applied to the vehicle dynamics equation.
Profit-oriented High-speed Railway Network Line Planning with Capacity Limitations
Abstract: Line planning is the transportation service's fundamental, which directly affects the subsequent operation plans. It is better to focus on the operational profit when considering the market competition for transportation operation plans. This paper aims to maximize the operational profit when optimizing the high-speed railway network line plan by constructing a mixed integer nonlinear programming model. The model integrates line planning and passenger route choice behaviors. An adaptive simulated annealing algorithm with neighborhood search is applied based on a given line pool. A heuristic passenger assignment method is developed to ensure a high level of passenger satisfaction. The proposed model and algorithm are experimentally evaluated. The instance results show that the operational profit and capacity utilization can be significantly improved. Compared with the designed greedy heuristic algorithm, the proposed algorithm performs better in operational profit improvement and has high efficiency.