Running Process Research Articles

Effect of Loading Pressure on Tribological Properties for Valve Plate Pair during the Running-In Process

The friction and wear performance of the valve plate pair significantly affects the service life and reliability of axial piston pumps. Loading pressure during the running-in process is crucial to its contact characteristics, friction coefficient, running-in time, wear rate, etc. In this article, mixed lubrication modeling and analysis of the effects of loading pressure on tribological performance for valve plate pair were conducted. A finite element model was established using fractal theory and a coupled Euler-Lagrange method. Ring-on-block tests were conducted to simulate the movement and tribological properties of the valve plate pair during the running-in process. Running-in tests of the axial piston pump were carried out to detect the valve plate’s wear. Results show that the effect of increased loading pressure on the maximum contact pressure decreases gradually. The increased loading pressure can shorten the running-in time without increasing the friction coefficient. The wear mechanisms are abrasive wear and adhesive wear during the running-in process. This study provides a reference for the running-in test of axial piston pumps.

Influence of sliding wear on contact characteristics based on 3-D wheel/rail contact model

During the process of starting, braking and running of the train, sliding contact between wheel and rail occurs. The wear caused by sliding contact exerts a noteworthy influence on the contact characteristics of wheel/rail. To analyze these characteristics, a three-dimensional wheel/rail contact wear model is established, and the contact characteristics at different wear depths are studied. The results indicate that at initial contact, the wheel/rail contact patch is approximately elliptical in shape and its area is 122.5 mm2. The von Mises stress of the wheel and rail is maximum in the subsurface at a distance of 2 mm from the contact interface, with maximum values of 559 MPa and 628 MPa respectively. When the wear depth is less than 0.5 mm, the wear depth, contact area and size increase quickly. As the amount of wheel contact wear increases, the maximum contact stress gradually decreases and the contact stress becomes uniform. In addition, the calculation results indicate that the contact patch shape does not always remain elliptical, the shape can change from elliptical to rectangular as the wear depth increases. As the increasing of wear amount, the contact stress gradient on the inner side of wheel contact surface increases.

An investigation of the effect of running-in with micron-sized diamonds on the lubrication performance of 5CB liquid crystal

The aim of this work was to examine the impact of running-in with micron-sized diamonds on the lubrication performance of 4-Cyano-4′-pentylbiphenyl (5CB) liquid crystal (LC). It was observed that an appropriate running-in pretreatment resulted in a remarkable 37.9% decrease in the coefficient of friction (COF) compared to friction tests without running-in. This improvement in lubrication performance is believed to be attributed to the formation of a textured surface during the running-in process. Additionally, the study found a significant correlation between COF and various surface parameters, namely Sa, Ssk, Sku, Svk, and Spk. The wear surface exhibits characteristics such as high Sku, negative Ssk, Svk/Spk ratios, and smaller Str under the optimal running-in conditions.

Numerical modeling and experimental investigation on fatigue failure and contact fatigue life forecasting for 8620H gear

Surface integrity parameters exert an enormous function on contact fatigue performance of gears. In this paper, a gear contact fatigue life prediction model that incorporates surface integrity parameters is proposed. The micropitting and pitting damage of failed gears are quantitatively analyzed through micro-characterization techniques. A three-dimensional contact analysis of rough surface is performed to simulate the morphology evolution during gear running-in. And the coupling effect of residual stress and rough morphology on the contact stress field and fatigue life is analyzed. Finally, residual stress optimization design is carried out based on the failed gear. Gears subjected to shot peening are designed and gear contact fatigue tests under various working conditions are performed. The research results indicate that the plastic deformation at the asperities level in the running-in process mainly occurs during the initial loading. The fatigue life significantly increases by improving the residual stress distribution on the tooth surface through shot peening process. The maximum relative error between predicted fatigue life and measured fatigue life is less than 20%, which effectively verifies the accuracy of the proposed model. The technique presented in this study could provide theoretical basis and data support for the anti-fatigue design and manufacturing of gears.

Innovative measurement system for saber curvature observation in straightening processes

High-strength wire materials are usually available as strip material and are subjected to a forming process such as punch-bending to produce parts for the electronics industry, for example. During the manufacturing process of the semi-finished product, residual stresses and plastic deformations are introduced into the wire by rolling and drawing processes. Straightening machines are used in the production lines to compensate for these. To increase the sustainability of these production lines, the straightening process is an essential step. Before the continuous manufacturing process starts, the straightening process must be set up and the optimal roller positions must be found. Once the process is set up, the roller position settings are usually not changed. Due to missing measurement systems for the straightening quality, it is not possible to react to fluctuations in the material properties. This leads to deviations in the dimensional accuracy of the components to be produced and thus to an increase in the rejection rate in the manufacturing processes.This paper presents two innovative measuring systems that can detect changes in saber curvature in flat wire during the straightening process. With the help of this information, the quality of the straightening process can be recorded during the running process. This enables the chance to build a control structure for the straightening quality and thus to implement demand-oriented straightening of semi-finished products. On the one hand, this means that the flat wire no longer must be overbent, which means that the strength of the material is not reduced anymore. On the other hand, the sensor information collected can be passed on to downstream processes. This creates the possibility of networking for the individual processes in a production line. This makes an important contribution to the development of intelligent manufacturing processes in line with the guiding principle of Industry 4.0.

Research on Case Study and Teaching Improvement of Civic Education Based on Ethics Theory

Abstract Curriculum Civic and Political Education is the requirement of cultivating talents in colleges and universities in the new era, and comprehensively promoting the construction of curriculum Civic and Political Education is a strategic move to implement the fundamental task of establishing morality and educating people. This paper begins with the case of civic and political education based on ethics and explores the case study approach to education. Then, it combines the DEMATEL algorithm and explanatory structural equation modeling and utilizes the DEMATEL-ISM algorithm to dig out the influencing factors affecting Civic and Political education so as to propose the improvement of the Civic and Political education method based on ethics. Furthermore, the improved teaching method is applied to explore the effects of civic and political education by combining the independent sample t-test method. Among them, the concept of nurturing, the idea of intention, and the environmental atmosphere, with a centrality of 7.982, 7.173, and 7.162, in turn, are the key influence indicators of ideological and political education. There are significant differences (P<0.01) in the experimental classes in the dimensions of patriotism and idealism education, dialectical materialism education, scientific quality and social responsibility education, and ethical teaching. In the case analysis process of the silent running through the Civics, to explore the application of curriculum Civics in the process of ethics case teaching, and to promote the deep integration of ethics case teaching and curriculum Civics.

Development of Building Design Optimization Methodology: Residential Building Applications

Building design optimization is a highly complex problem, requiring long computational running processes because of the many options that exist when a building is being designed. This paper introduces an integrated approach through which to perform this optimization within an acceptable time frame. The approach includes the methods of variable selection, model simplification, and a sequential optimization process. Using singular value decomposition, a large number of design variables is reduced to a smaller subset that can be solved more quickly through the optimization algorithm. To expedite the variable selection process, a modeling approach that quickly simulates annual energy consumption was developed to replace full annual energy simulations. The developed methodology was applied to two residential buildings in the US, and the results are discussed herein. To assess the accuracy of the integrated optimization methodology, the optimized life cycle costs are compaa variables demonstrating the strongest contributions in the optimization study were identified. The proposed methodology significantly shortened the time requirements for the optimization processes of the two case studies by 74% and 84%; the optimized life cycle costs were within 0.05% and 0.06%, respectively, of the optimum point.

Running-in behavior of dual-mobility cup during the gait cycle: A finite element analysis.

The running-in process is considered an essential aspect of the comprehensive wear process. The phenomenon of running-in occurs during the initial stages of wear in the prosthetic hip joint. Within the field of tribology, the running-in phenomenon of the hip joint pertains to the mechanism by which the contact surfaces of the artificial hip joint components are adjusted and a suitable lubricating film is formed. During the process of hip joint running-in, there is an interaction between the metal surface of the ball and the joint cup, which results in adjustments being made until a steady state is achieved. The achievement of desirable wear existence and reliable performance of artificial hip joint components are reliant upon the tribological running-in of the hip joint. Despite the establishment of current modeling approaches, there remains a significant lack of understanding concerning running-in wear, particularly the metal-on-polyethylene (MoP) articulations in dual-mobility cups (DMC). An essential aspect to consider is the running-in phase of the dual mobility component. The present study employed finite element analysis to investigate the running-in behavior of dual mobility cups, wherein femoral head components were matched with polyethylene liners of varying thicknesses. The analysis of the running-in phase was conducted during the normal gait cycle. The results of this investigation may be utilized to design a dual-mobility prosthetic hip joint that exhibits minimal running-in wear.

A Practical Guide to QI Data Analysis: Run and Statistical Process Control Charts.

Data analysis utilizing run charts and statistical process control (SPC) charts is a mainstay of quality improvement (QI) work. These types of time series analyses allow QI teams to evaluate patterns in data that may not be apparent with pre- and postintervention analysis. A run chart is most useful at the onset of a project when data points may be limited; points can be added prospectively to monitor for changes. An SPC chart is needed to determine if the system is "out of control," indicating an instance of special cause variation, and is recommended for more robust data analysis. These charts are valuable tools in identifying patterns of change, but cannot indicate what caused the change. QI teams can further investigate significant patterns to identify the impact of interventions and promote continued change or sustainability. In this article, we will provide a practical guide to the basics of run and SPC charts, including how to create and interpret them. The reader can use the supplemental data tables to gain the skills needed to build their own charts with readily available software. Finally, we will review more specialized software options that can assist in creation of run and SPC charts.

ANALYSIS OF THE MICROSERVICE ARCHITECTURE OF THE SMART CITY

Recently, the concept of “Smart Cities” has been significantly improved along with the growth and development of the Internet of Things as a new form of sustainable development. Smart cities rely on an independent and distributed infrastructure that includes information processing and management systems, a diverse network infrastructure, and a sensitivity that includes millions of information sources. However, due to the ever-increasing amount of data and the number of connected IoT devices, issues such as high latency, bandwidth barriers, security and privacy, and scalability are the result of the ongoing construction of a smart city network. Developing an efficient, secure, and scalable distributed architecture by bringing computer resources and storage closer to the endpoint is necessary to overcome the limitations of today’s smart city network. There are many types of smart services that aim to automate and perform repetitive routine tasks. In addition, they come in different forms depending on the city’s population, culture, including the level of awareness of citizens, geography, and schedule. Not to mention, on a micro-technical level, they tend to create large data sets with fast continuous execution, thus falling into the category of big data, and therefore can be a source of analytical data. Microservice architectures are born as a solution to this problem. By implementing a single small function that is confined to a running process, independent microservices can be deployed separately in a distributed system. In the context of mobility in a smart city, a service meets the need of a citizen who needs to move from one part of the city to another or provides useful information for the same purpose. In this article, we demonstrate how microservice architecture can be used to create IoT services for multimobility in a smart city.

Laser fluctuation effects in an EIT engine

In contact with a hot and a cold reservoir, the three-level atom driven by a strong coupling field generates photons via a sequence of transitions that mimics the running process of a heat engine. The brightness of the output photon can be much larger than that of the hot reservoir, and its efficiency could be larger than that of the Carnot engine [Phys. Rev. A 94, 053859 (2016)PLRAAN1050-294710.1103/PhysRevA.94.053859]. The core element of the mechanism is an interference effect called electromagnetically induced transparency caused by the coupling field, which is commonly a perfect laser without any random change in the phase. In this paper, we investigate a more realistic model where the temporal fluctuation of the coupling field is considered. By applying the laws of thermodynamics in the analysis, we find that in addition to the reduced power of the engine, a relatively strong fluctuation changes the properties of the system radically, even making it lose the quality of being a heat engine. We have found the corresponding criteria for the maximal allowed fluctuation. The entropy changes when the engine works below the laser threshold suggest that the effect of the fluctuation is equivalent to increasing the temperature of the cold reservoir.

A running-in strategy based on an efficient wear simulation model for double circular-arc spiral bevel gears

A proper running-in process is necessary for double circular-arc spiral bevel gears to achieve desirable meshing performance. However, this type of gear transmission lacks a suitable running-in wear model, which brings great difficulties to the design of appropriate running-in strategies. To address this problem, the present study establishes an efficient numerical wear model to reveal the wear behavior of double circular-arc spiral bevel gear pairs, based on which a step-wise load running-in strategy is proposed. The established Archard's wear model considers the meshing characteristics of double circular-arc spiral bevel gears and sets a small threshold value, which can reflect the wear behavior of this gear in the running-in stage. To improve the computation efficiency, a two-step parameter updating strategy is proposed to enhance the iteration of p and s. The wear simulation reveals the quantitative relationship contact pressure and running-in cycle during the running-in process. Based on the reveal relationship, a step-wise load running-in strategy is proposed to sharpen the running-in period. The developed wear model and the proposed running-in strategy can be extended to other types of gears with circular-arc profiles.

Deterministic surface roughness effects on elastic material contact with shear thinning fluid media

Abstract The formation of lubrication films is described using the hydrodynamic lubrication theory, which is based on the Reynolds equation that includes shear thinning behaviors of lubricant. Contacting surfaces are considered to undergo elastic deformation owing to concentrated contact pressures that exceed 1.0 GPa in most engineering applications. Under the contact condition of a high load on a relatively small contact area, elastic deformation of contacting bodies directly influences the formation of the lubricated film. Elastohydrodynamic lubrication (EHL) analysis is applied to correctly analyze the lubricated contact. Under an EHL contact, the scale of the lubrication film thickness is frequently less than that of the surface roughness that results from either the manufacturing or running-in processes. In this work, surface roughness is considered in detail, and two-dimensional surface roughness is measured as that characterizing general engineering surface roughness. The deterministic method regarding the surface roughness is considered for computing EHL film formation under several contact conditions such as load, contact velocity, and elasticity of contacting materials.

Study on dynamic characteristics of urban rail transit vehicle considering faulty axle-box bearings under variable speeds

Axle-box bearing is the key component of urban rail transit vehicles, and its performance status seriously affects the operation safety and stability of the train. Therefore, analyzing the dynamic response of a vehicle system by considering axle-box bearings is the premise of ensuring its safety. Besides, vehicles generally run under the condition of variable speeds, which leads to more complex dynamic response for the vehicle system. Accordingly, studying the influence of faulty axle-box bearings on the vehicle system under variable speeds can reflect the running situation of trains more realistically. In this paper, a dynamics model of axle-box bearings is considered in the vehicle-track coupling model, and the dynamic response of the vehicle system with faulty bearings under variable speeds is analyzed. Firstly, a vehicle-track coupling dynamics model considering axle-box bearings is established, which considers the coupling effect between axle-box bearings and other vehicle components. The bearing inner race is fixedly connected with the axle shaft, and the bearing outer race is fixedly connected with the axle-box housing. Then, an outer race defect model and an inner race defect model of axle-box bearings are respectively established to simulate the internal fault excitation which is often generated in the running process of train bearings. Finally, considering faulty axle-box bearings and variable speeds, the dynamic response of the vehicle system is simulated by the proposed model, whose effectiveness is validated through the theoretical analysis and field tests. The test results show that the axle-box bearing with an outer or inner race defect has a certain influence on the dynamic response of the vehicle system under variable speeds.

Effects of Nozzle Diameter and Holes Number on the Performance and Emissions of a Gasoline Direct Injection Engine

The goal of the current study is to estimate how a gasoline direct injection (GDI) engine's performance and emissions are affected by the fuel injector nozzle diameter and hole number of its injectors. A thermodynamic mathematical modelling has been created utilizing a software program written in the MATLAB language to simulate the two-zone combustion process of a four-stroke direct injection engine running on gasoline at (Rotation Engine Speed 3000 revolution per minute (rpm), 40 MPa injection pressure, compression ratio 9.5, and spark timing 145°). The first law of thermodynamics, equation of energy, mass conserving, equation of state, and mass fraction burned were all used in the creation of the software program. The study was carried out at five different nozzle diameters (0.250, 0.350, 0.450, 0.550, and 0.650 mm) and nozzle hole numbers (4,6,8,10,12). The results show that the GDI engine's performance and emissions are significantly influenced by variations in nozzle hole diameter and number. It was shown that engine power, heat transfer, cylinder pressure, and temperature increased with increasing nozzle hole diameter and number of nozzle holes and the maximum value was seen with nozzle hole diameter 0.650 mm and (12) holes. The lowest value for the nozzle hole diameter and number of holes was found to be 0.250 mm and 4 nozzle holes, which resulted in the lowest emissions of carbon monoxide CO and nitrogen monoxide NO. The study was also conducted for different operating conditions (Rotation Engine speed of 1000, 2000, 3000, 4000, 5000 rpm ,35 MPa injection pressure , compression ratio of 11.5 , and spark timing of 140° ) and the same nozzle diameters and nozzle holes number mentioned previously to estimate the maximum values for temperature, pressure, power , heat transfer and emissions . The results of the second part of the study showed that the highest of maximum values of temperature, pressure, and emissions were at of 1000 rpm, a nozzle diameter of 0.650 mm, and (12) holes. The highest values for maximum power at 4000 rpm, a nozzle diameter of 0.650 mm and (12) holes, while the highest maximum values for heat transfer are at 5000 rpm, a diameter of 0.65mm and (12) holes.

High-fidelity simulations of the run-in process for a pebble-bed reactor

Pebble-bed reactors (PBRs) rely on a continual feed of fuel pebbles being cycled through the core. As a result, they require a “run-in” period in order to reach an equilibrium state. The run-in period for a PBR is a complex, time-dependent problem that requires the injection of new fuel, different types of fuel, and power increases. This complexity in the run-in makes it important to capture the physical processes in order to generate an accurate representation. The present work details the creation of a high-fidelity Monte Carlo methodology for analyzing the run-in and subsequent approach to equilibrium for PBRs. The methodology entails a Python module wrapped around Serpent so as to perform neutronics calculations, move pebbles, refuel the core, and discharge pebbles, thereby modeling the explicit behavior of the PBR run-in. Three run-in simulations (a constant temperature profile, a linear temperature profile, and a constant temperature profile using control rods) were examined in order to identify the key physical phenomena present in the run-in process. Utilizing kugelpy, we found the inclusion of a temperature profile to be important for accurately capturing a discharge burnup (around 141 MWd/kg), a consistent k-eff (around 1.005), and an average pebble power (around 2.5 kW/pebble) that all fall within acceptable limits.

In-depth study of direct and derived acoustic emission parameters and their information content for classifying lubricated tribological sliding contacts

Acoustic signals (AE) have become a valuable tool for monitoring various tribological systems. This study investigates three key tribological behaviors: the initial running-in process, severe wear, and the lubrication state of journal bearings using four AE postprocessing methods. These methods are friction power-scaled quadratic mean (SRMS), power spectrum (PSD), normalized power spectrum (nPSD), and a statistical hit-rate (HR) analysis of the raw AE signal. The research draws on data from four tests conducted in three set-ups: Ring-on-Disc (RoD), Ring-on-Liner (RoL), and Journal-bearing-adapter (JBA) test configurations. AE measurements were taken at both 1 Hz and 1 kHz for the quadratic mean value (RMS), as well as at 900 kHz for short time intervals during each test to capture the raw signal data. In conjunction with other measured parameters like friction coefficient, temperature, contact potential, and wear, we establish correlations between the acoustic parameters and tribological behaviors. The findings indicate that SRMS and nPSD are valuable for identifying the end of the initial running-in phase. All four methods are effective in recognizing high wear states, with nPSD and HR even distinguishing between different wear phenomena. The lubrication state of journal bearings is best assessed using nPSD, allowing users to monitor certain geometric changes in the bearing.

The triboelectric sensor based on PDMS/SGO for human running posture and physical fitness health monitoring

ABSTRACT Recently, research about the intelligent sports equipment based on triboelectric sensor for athlete posture monitoring has made progress. However, the exploration of new triboelectric materials remains an important challenge to be faced. Hence, we ingeniously design a polydimethylsiloxane (PDMS)/silanized graphite oxide (SGO)-based triboelectric nanogenerator (PS-TENG) for running posture and physical health monitoring. The introduction of SGO has improved the electron capture capability of PDMS, thereby achieving high output of PS-TENG. From the results, under an 60 MΩ resistance, the power density of PS-TENG reaches a peak of 1780 mW·m−2. Furthermore, athletes undergo various postures during the running process, so monitoring special postures is very meaningful, such as jogging, long jump, walking, etc. Especially, according to the self-charging mechanism, PS-TENG can indirectly evaluate physical energy analysis during running by storing electrical energy in capacitors. This triboelectric sensor can assist in posture monitoring and physical fitness monitoring during running.

Implementation of a Children's Hospital Acute Care Behavior Response Team.

Pediatric patients with behavioral needs are frequently admitted to the hospital for medical care; when behavioral crises occur, patients and staff are at risk for injury. Our aim was to implement a behavior response team (BRT) to increase the days between employee injury due to aggressive patient interactions on the inpatient medical units from 99 to 150 over 1 year. A multidisciplinary team used quality improvement methods to design and implement the BRT system that includes 2 options: huddle to proactively plan for patients exhibiting early signs of escalation and STAT for immediate help for patients with imminent risk of harm to self or others. Using run and statistical process control charts, we tracked events per month, days between Occupational Safety & Health Administration-recordable events, and violent restraint use over time for 1 year after implementation. Staff pre and postimplementation surveys were compared to assess staff perception of safety and support provided by the BRT intervention. The BRT was implemented across the inpatient system in July 2020, with an average number of 13 events per month. Days between Occupational Safety & Health Administration-recordable events remained stable with a maximum of 134 days. Restraint use remained stable at 0.74 per 1000 patient days. The perception of behavioral support available to staff increased significantly pre to postsurvey. The implementation of a BRT can improve staff perception of support and confidence in safely caring for patients with behavior needs on the inpatient medical unit, although additional provider- and system-level improvements are needed to prevent employee injuries.

Feature extraction algorithm of anti-jamming cyclic frequency of electronic communication signal

Abstract Anti-jamming cyclic frequency feature extraction is an important link in identifying communication interference signals, which is of great significance for eliminating electronic communication interference factors and improving the security of electronic communication environment. However, when the traditional feature extraction technology faces a large number of data samples, the processing capacity is low, and it cannot solve the multi-classification problems. For this type of problem, a method of electronic communication signal anti-jamming cyclic frequency feature extraction based on particle swarm optimization-support vector machines (PSO-SVM) algorithm is proposed. First, the SVM signal feature extraction model is proposed, and then the particle swarm optimization (PSO) algorithm is used. Optimize the kernel function parameter settings of SVM to raise the classifying quality of the SVM model. Finally, the function of the PSO-SVM signal feature extraction model is tested. The results verify that the PSO-SVM model begins to converge after 60 iterations, and the loss value remains at about 0.2, which is 0.2 lower than that of the SVM technique. The exactitude of signal feature extraction is 90.4%, and the recognition effect of binary phase shift keying signal is the best. The complete rate of signal feature extraction is 85%. This shows that the PSO-SVM model enhances the sensitivity of the anti-jamming cyclic frequency feature, improves the accuracy of the anti-jamming cyclic frequency feature recognition, reduces the running process, reduces the time cost, and greatly increases the performance of the SVM method. The good model performance also improves the application value of the method in the field of electronic communication.