Search

This paper presents an integrated procedure for dynamic impact predictions and an experimental verification of rubber–metal bonded components with fluid to be used as a potential application in rail vehicle suspensions. There are three steps involved in the procedure. First, a quasi-static analysis was performed to verify the elastic properties of the rubber material using hyperelastic models. Second, a dynamic impact evaluation on selected hydro-mounts without fluid was conducted using the Natural Frequency Region (NFR) approach. Finally, a coupled NFR (with Fluid-Structural-Interaction) approach, different from the usual viscoelastic methods, was initiated to predict the dynamic impact responses of these components with the fluid in time domain. All the analyses have been validated with experimental data. The first two stages have been briefly described and the third stage is detailed in this paper. It should be noted that a powerful computer with multi-central processing units is essential to obtain a reasonable result within an acceptable time frame. It took approximately 40 h wall-clock time to complete the analysis using a workstation with 10 central processing units. It has been suggested that the natural frequency region–fluid–structure interaction methodology is reliable and could be used at the design stage and for engineering applications. [ABSTRACT FROM AUTHOR]

The objective of the study is to develop a mathematical model to measure the quality cost and economic benefits of the implementation of the quality improvement program within a business process of manufacturing companies. The economic benefits are obtained from saving quality costs resulting from achieving operational performance targets. The research methodology is used; firstly, the authors developed a conceptual model as a basis for a mathematical model. Secondly, they used a numerical experiment to illustrate the measurement of the effect of the change of the model parameters' values (e.g. number of performance indicators, and level target of performance target) toward the performance target achieved, cost savings obtained, and economic benefits. If the value of the model parameters increases, then the economic benefits will increase as well, and give a shorter return period of investment. And vice versa, if the value of the model parameters decreases, then the economic benefits will decrease as well and give a longer return period of investment. The model describes the dynamics of the quality costs and economic benefits periodically obtained from a quality improvement program. [ABSTRACT FROM AUTHOR]

The aim of the research paper is to develop algorithms for manufacturers' agents that would allow them to sequence their own operation plans and to develop a multi-agent infrastructure to allow operation pair agents to cooperatively adjust the timing of manufacturing operations. The scheduling problem consisted of jobs with fixed process plans and of manufacturers collectively offering the necessary operations for the jobs. Manufacturer agents sequenced and pair agents timed each operation as and when required. Timing an operation triggered a cascade of conflicts along the job process plan that other pair agents would pick up on and would take action accordingly. The conventional approach performs conflict resolution in series and manufacturer agents as well as pair agents wait until they are allowed to sequence and time the next operation. The limiting assumption behind that approach was systematically removed, and the proposed approach allowed manufacturers to perform operation scheduling in parallel, cutting down tenfold on the computation time. The multi-agent infrastructure consists of the Protégé knowledge base, the Pellet semantic reasoner and the Workflows and Agent Development Environment (WADE). The case studies used were the MT6, MT10 and LA19 job shop scheduling problems; and an industrial use case was provided to give context to the manufacturing environment investigated. Although there were benefits from the decentralised manufacturing system, we noted an optimality loss of 34% on the makespans. However, for scalability, our approach showed good promise. [ABSTRACT FROM AUTHOR]

The manufacturing industry is considered as one important sector, which has a significant influence on the economic growth of a country. The increase of fierce competition among products requires the company to satisfy their customers by making high-quality products with competitive prices and at on-time deliveries. This study aims to implement lean manufacturing in one of the furniture companies in Indonesia to minimize waste in the production floor. Value Stream Mapping (VSM) will be used as a tool to identify waste by separating value-added activities and non-value added activities in the production process. A future state map is developed with new and improved processes. Future state map makes the improved process more effective and more efficient. The critical waste found on the production floor in motion. Improvements are made using 5W1H techniques and ECRS principles, two simple tools of kaizen. The workload of operator consideration was also done to avoid bottlenecks and decrease the lead time. The result was quietly remarkable as the lead time decreased by around 4.79% and able to balance the workload received by the operator. [ABSTRACT FROM AUTHOR]

This document is a correction notice for an article titled "Human bone marrow-derived mesenchymal stem cell-secreted exosomes overexpressing microRNA-34a ameliorate glioblastoma development via down-regulating MYCN." The notice states that Dr. Jianfang Ning was not involved in the study and publication of the retracted article, as confirmed by the University of Minnesota. The original article can be found online at the provided link. Springer Nature, the publisher, remains neutral regarding jurisdictional claims and institutional affiliations. The authors of the article are Bin Wang, Zhong-Hua Wu, Ping-Yang Lou, Chang Chai, Shuang-Yin Han, Jian-Fang Ning, and Ming Li. [Extracted from the article]

• A capable CSFO method for the time-variant reliability analysis is proposed. • Refined FEM with bilinear CZM to analyze interface damage of slab track is developed. • Point estimate-based dimension reduction is utilized to improve computing efficiency. • Time-variant reliability of interlayer damage under different conditions is studied. This study proposes the combining second-order fourth-moment and outcrossing method for evaluating the time-variant reliability of slab tracks' interlayer damage. The merit of the method is to improve significantly the computing efficiency and accuracy for the implicit and strong nonlinear limit state function. Furthermore, the effects of narrow joints damage and temperature load on the time-variant reliability of slab tracks' interlayer damage are investigated. Narrow joints damage is an inducement for the decrease of time-variant reliability index of slab tracks' interlayer damage, and the index decreases more violently with the increase of temperature rise than that of positive temperature gradient. [ABSTRACT FROM AUTHOR]

• The high temperature of the tunnel leads to the warpage of track slab and rail. • The temperature between the track slab surface and tunnel floor is linear relationship. • The temperature of the tunnel increase the dynamic response of the vehicle-track system. • High temperature tunnel conditions degrade the service state of the CRTS Ⅱ BT. Considering the dynamic balance of heat conduction between tunnel floor and track structure, heat convection and heat radiation between track surface and air, a finite element model for the temperature field of CRTS Ⅱ ballastless track in the high temperature tunnel is proposed and the dynamic responses of the vehicle-track coupling system are studied. Firstly, the influences of the temperature of the tunnel floor on the temperature distribution and warpage of the track are investigated. Secondly, the dynamic responses of the VTCS excited by the additional irregularity of the track induced by the temperature of the tunnel floor are investigated, and the effects of track deformation on dynamic characteristics at different speeds are compared. The findings demonstrate a linear relationship between the maximum and minimum temperatures of the upper and lower surfaces of the track slab and the temperature of the tunnel floor. In comparison to rail, the maximum displacement of the slab is larger, and the warpage deformation with symmetrical distribution of the track slab is characterized by concave in the middle and arching on both sides. The fastener stiffness has no effect on the deformation of the slab, but the vertical displacement of rail increasess as the fastener stiffness enlarge. Temperature load enlarges the excitation of the wheel-rail system so that intensifies the dynamic response. The faster of the speed of vehicle is, the effect of additional track irregularity on the dynamic response is the more pronounced. The research reveals the mechanism of high temperature tunnel on the service state of track, which supplies a theoretical basis for the design and maintenance of track. [ABSTRACT FROM AUTHOR]

Fault diagnosis is one of the important applications of edge computing in the Industrial Internet of Things (IIoT). To address the issue that traditional fault diagnosis methods often struggle to effectively extract fault features, this paper proposes a novel rolling bearing fault diagnosis method that integrates Gramian Angular Field (GAF), Convolutional Neural Network (CNN), and Vision Transformer (ViT). First, GAF is used to convert one-dimensional vibration signals from sensors into two-dimensional images, effectively retaining the fault features of the vibration signal. Then, the CNN branch is used to extract the local features of the image, which are combined with the global features extracted by the ViT branch to diagnose the bearing fault. The effectiveness of this method is validated with two datasets. Experimental results show that the proposed method achieves average accuracies of 99.79% and 99.63% on the CWRU and XJTU-SY rolling bearing fault datasets, respectively. Compared with several widely used fault diagnosis methods, the proposed method achieves higher accuracy for different fault classifications, providing reliable technical support for performing complex fault diagnosis on edge devices. [ABSTRACT FROM AUTHOR]

Atmospheric temperature and directed solar radiation have a significant effect on the temperature field of high-speed railway (HSR) concrete bridge and ballastless track structure. However, temperature actions are random process of which distribution laws are difficult to explore, and existing statistical methods for structure temperature analysis are still not precise. So far, there are few researches for annual temperature spectra and design codes for bridge–track system. Based on the one-year observation data, this paper investigated the temperature actions for Chinese HSR bridge–track structure. By utilizing reliability high moment theory, a statistical method which could built virtual distribution was put forward. Based on the renewed study, the effects of waterproof for deck were taken into consideration, a temperature action model was proposed which is suitable for both bridge and track structure. In addition, for track structure, the previous temperature load models were modified. Apart from that, by proposing the concepts of temperature uniform and fluctuant spectra, the research evaluated service performance of structure. Finally, the distribution regularities of uniform temperature spectra were fitted by Fourier series, and the relationship between structural and atmospheric uniform temperature was established (formula (25) ). As a result, according to 50 years recorded atmospheric temperature data, the prediction model of the structure extreme temperature was suggested, and by taking the recurrence interval of 100, 150 and 300 years, the extreme temperatures of the system are 52.23, 54.34 and 57.77 °C. [ABSTRACT FROM AUTHOR]