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Full-Text Articles in Engineering

Bcse: Blockchain-Based Trusted Service Evaluation Model Over Big Data, Fengyin Li, Xinying Yu, Rui Ge, Yanli Wang, Yang Cui, Huiyu Zhou Mar 2022

Bcse: Blockchain-Based Trusted Service Evaluation Model Over Big Data, Fengyin Li, Xinying Yu, Rui Ge, Yanli Wang, Yang Cui, Huiyu Zhou

Big Data Mining and Analytics

The blockchain, with its key characteristics of decentralization, persistence, anonymity, and auditability, has become a solution to overcome the overdependence and lack of trust for a traditional public key infrastructure on third-party institutions. Because of these characteristics, the blockchain is suitable for solving certain open problems in the service-oriented social network, where the unreliability of submitted reviews of service vendors can cause serious security problems. To solve the unreliability problems of submitted reviews, this paper first proposes a blockchain-based identity authentication scheme and a new trusted service evaluation model by introducing the scheme into a service evaluation model. The new …


Big Data With Cloud Computing: Discussions And Challenges, Amanpreet Kaur Sandhu Mar 2022

Big Data With Cloud Computing: Discussions And Challenges, Amanpreet Kaur Sandhu

Big Data Mining and Analytics

With the recent advancements in computer technologies, the amount of data available is increasing day by day. However, excessive amounts of data create great challenges for users. Meanwhile, cloud computing services provide a powerful environment to store large volumes of data. They eliminate various requirements, such as dedicated space and maintenance of expensive computer hardware and software. Handling big data is a time-consuming task that requires large computational clusters to ensure successful data storage and processing. In this work, the definition, classification, and characteristics of big data are discussed, along with various cloud services, such as Microsoft Azure, Google Cloud, …


Exploiting More Associations Between Slots For Multi-Domain Dialog State Tracking, Hui Bai, Yan Yang, Jie Wang Mar 2022

Exploiting More Associations Between Slots For Multi-Domain Dialog State Tracking, Hui Bai, Yan Yang, Jie Wang

Big Data Mining and Analytics

Dialog State Tracking (DST) aims to extract the current state from the conversation and plays an important role in dialog systems. Existing methods usually predict the value of each slot independently and do not consider the correlations among slots, which will exacerbate the data sparsity problem because of the increased number of candidate values. In this paper, we propose a multi-domain DST model that integrates slot-relevant information. In particular, certain connections may exist among slots in different domains, and their corresponding values can be obtained through explicit or implicit reasoning. Therefore, we use the graph adjacency matrix to determine the …


Sampling With Prior Knowledge For High-Dimensional Gravitational Wave Data Analysis, He Wang, Zhoujian Cao, Yue Zhou, Zong-Kuan Guo, Zhixiang Ren Mar 2022

Sampling With Prior Knowledge For High-Dimensional Gravitational Wave Data Analysis, He Wang, Zhoujian Cao, Yue Zhou, Zong-Kuan Guo, Zhixiang Ren

Big Data Mining and Analytics

Extracting knowledge from high-dimensional data has been notoriously difficult, primarily due to the so-called "curse of dimensionality" and the complex joint distributions of these dimensions. This is a particularly profound issue for high-dimensional gravitational wave data analysis where one requires to conduct Bayesian inference and estimate joint posterior distributions. In this study, we incorporate prior physical knowledge by sampling from desired interim distributions to develop the training dataset. Accordingly, the more relevant regions of the high-dimensional feature space are covered by additional data points, such that the model can learn the subtle but important details. We adapt the normalizing flow …


Toward Intelligent Financial Advisors For Identifying Potential Clients: A Multitask Perspective, Qixiang Shao, Runlong Yu, Hongke Zhao, Chunli Liu, Mengyi Zhang, Hongmei Song, Qi Liu Mar 2022

Toward Intelligent Financial Advisors For Identifying Potential Clients: A Multitask Perspective, Qixiang Shao, Runlong Yu, Hongke Zhao, Chunli Liu, Mengyi Zhang, Hongmei Song, Qi Liu

Big Data Mining and Analytics

Intelligent Financial Advisors (IFAs) in online financial applications (apps) have brought new life to personal investment by providing appropriate and high-quality portfolios for users. In real-world scenarios, identifying potential clients is a crucial issue for IFAs, i.e., identifying users who are willing to purchase the portfolios. Thus, extracting useful information from various characteristics of users and further predicting their purchase inclination are urgent. However, two critical problems encountered in real practice make this prediction task challenging, i.e., sample selection bias and data sparsity. In this study, we formalize a potential conversion relationship, i.e., user→activated user→client and decompose this relationship into …


A Comparison Of Computational Approaches For Intron Retention Detection, Jiantao Zheng, Cuixiang Lin, Zhenpeng Wu, Hong-Dong Li Mar 2022

A Comparison Of Computational Approaches For Intron Retention Detection, Jiantao Zheng, Cuixiang Lin, Zhenpeng Wu, Hong-Dong Li

Big Data Mining and Analytics

Intron Retention (IR) is an alternative splicing mode through which introns are retained in mature RNAs rather than being spliced in most cases. IR has been gaining increasing attention in recent years because of its recognized association with gene expression regulation and complex diseases. Continuous efforts have been dedicated to the development of IR detection methods. These methods differ in their metrics to quantify retention propensity, performance to detect IR events, functional enrichment of detected IRs, and computational speed. A systematic experimental comparison would be valuable to the selection and use of existing methods. In this work, we conduct an …


Advances In The Application Of Biomimetic Surface Engineering In The Oil And Gas Industry, Yanbao Guo, Zheng Zhang, Siwei Zhang Oct 2020

Advances In The Application Of Biomimetic Surface Engineering In The Oil And Gas Industry, Yanbao Guo, Zheng Zhang, Siwei Zhang

Friction

Friction is widespread in almost every field in the oil and gas industry, and it is accompanied by huge energy losses and potential safety hazards. To deal with a series of questions in this regard, biomimetic surfaces have been developed over the past decades to significantly reduce economic losses. Presently, biomimetic surface engineering on different scales has been successfully introduced into related fields of the oil and gas industry, such as drill bits and the inner surfaces of pipes. In this review, we focused on the most recent and promising efforts reported toward the application of a biomimetic surface in …


Rubber Plunger Surface Texturing For Friction Reduction In Medical Syringes, Haytam Kasem, Harel Shriki, Lihi Ganon, Michael Mizrahi, Kareem Abd-Rbo, Abraham J. Domb Oct 2020

Rubber Plunger Surface Texturing For Friction Reduction In Medical Syringes, Haytam Kasem, Harel Shriki, Lihi Ganon, Michael Mizrahi, Kareem Abd-Rbo, Abraham J. Domb

Friction

Friction is a genuine issue in the use of many medical devices involving rubbery materials such as plungers in medical syringes. This paper presents a new direction for the reduction of friction in medical syringes based on surface texturing of the rubber plunger. The specimens were prepared by casting poly(vinylsiloxane) (PVS) rubber into a pre-fabricated negative template obtained by 3D printing. Friction tests were performed on a home-made test-rig. It was clearly shown that friction resistance can be considerably manipulated when using textured plungers.


Erosive Wear Properties Of Za-27 Alloy-Based Nanocomposites: Influence Of Type, Amount, And Size Of Nanoparticle Reinforcements, Aleksandar Vencl, Ilija Bobić, Biljana Bobić, Kristina Jakimovska, Petr Svoboda, Mara Kandeva Oct 2020

Erosive Wear Properties Of Za-27 Alloy-Based Nanocomposites: Influence Of Type, Amount, And Size Of Nanoparticle Reinforcements, Aleksandar Vencl, Ilija Bobić, Biljana Bobić, Kristina Jakimovska, Petr Svoboda, Mara Kandeva

Friction

Metal matrix nanocomposites (MMnCs) comprise a metal matrix filled with nanosized reinforcements with physical and mechanical properties that are very different from those of the matrix. In ZA-27 alloy-based nanocomposites, the metal matrix provides ductility and toughness, while usually used ceramic reinforcements give high strength and hardness. Tested ZA-27 alloy-based nanocomposites, reinforced with different types (SiC and Al2O3), amounts (0.2 wt.%, 0.3 wt.%, and 0.5 wt.%) and sizes (25 nm, 50 nm, and 100 nm) of nanoparticles were produced through the compocasting process with mechanical alloying pre-processing (ball milling). It was previously shown that the presence of nanoparticles in ZA-27 …


Friction And Wear Behaviors Of Mos2-Multi-Walled-Carbon-Nanotube Hybrid Reinforced Polyurethane Composite Coating, Zhaozhu Zhang, Mingming Yang, Junya Yuan, Fang Guo, Xuehu Men Oct 2020

Friction And Wear Behaviors Of Mos2-Multi-Walled-Carbon-Nanotube Hybrid Reinforced Polyurethane Composite Coating, Zhaozhu Zhang, Mingming Yang, Junya Yuan, Fang Guo, Xuehu Men

Friction

MoS2-multi-walled-carbon-nanotube (MWCNT) hybrids containing two-dimensional MoS2 and one-dimensional MWCNTs were synthesized through a one-step hydrothermal reaction. X-ray-diffraction and transmission-electron-microscopy results demonstrated that MoS2 nanosheets were successfully synthesized, and uniformly anchored on the MWCNTs' surfaces. Furthermore, the effects of the MoS2-MWCNT hybrids on the tribological performances of polyurethane composite coatings were investigated using a UMT-2MT tribo-tester. Friction and wear test results revealed that the friction coefficient and wear rate of a 3 wt% MoS2-MWCNT-1 filled polyurethane composite coating were reduced by 25.6% and 65.5%, respectively. The outstanding tribological performance of the MoS2-MWCNT-1 reinforced polyurethane composite coating was attributed to the excellent …


Sliding Friction Of Shale Rock On Dry Quartz Sand Particles, Huijie Zhang, Shuhai Liu, Huaping Xiao Oct 2020

Sliding Friction Of Shale Rock On Dry Quartz Sand Particles, Huijie Zhang, Shuhai Liu, Huaping Xiao

Friction

The sliding friction of rock, involving all kinds of particles at the contact surface, is relevant to many problems, ranging from those in artificial engineering to earthquake dynamics. In this work, the frictional performance of the shale rock-dry quartz sand contact was investigated using a self-developed testing device. The study showed that the coefficient of friction of the contact increases with nominal stress and that the corresponding friction force increases approximately linearly with nominal stress, which is directly related to the contact stress between each single sand particle and rock shale. An overall dynamic coefficient, γ, reflecting the response of …


Friction Predication On Pin-To-Plate Interface Of Ptfe Material And Steel, Zhuming Bi, Donald W. Mueller Oct 2020

Friction Predication On Pin-To-Plate Interface Of Ptfe Material And Steel, Zhuming Bi, Donald W. Mueller

Friction

In this paper, the friction behavior at a pin-to-plate interface is investigated. The pin and plate are made of Polytetrafluoroethylene (PTFE) and steel, respectively, and there is a reciprocating motion at the interface. Governing mathematical models for the relations of design variables and frictions are investigated, and a general procedure is proposed to solve the developed models and predict the friction forces at the interface subjected to given test conditions. Novel models have been developed to represent intrigued friction behaviors affected by various factors such as pin geometrics and finishes, lubrication conditions, and reciprocating speed. The test data from experiments …


Significant Friction Reduction Of High-Intensity Pulsed Ion Beam Irradiated Wc-Ni Against Graphite Under Water Lubrication, Gaolong Zhang, Yuechang Wang, Ying Liu, Xiangfeng Liu, Yuming Wang Oct 2020

Significant Friction Reduction Of High-Intensity Pulsed Ion Beam Irradiated Wc-Ni Against Graphite Under Water Lubrication, Gaolong Zhang, Yuechang Wang, Ying Liu, Xiangfeng Liu, Yuming Wang

Friction

Two types of commercial WC-Ni samples were irradiated with the High-intensity pulsed ion beam (HIPIB). Both the surface characteristics and tribo-characteristics of the non-irradiated and irradiated WC-Ni samples, sliding against graphite under water lubrication, were compared. Quite low steady friction coefficients (approximately of 0.02) of the irradiated WC-Ni were observed. The surface topographies and components were investigated. The quite low friction of the irradiated WC-Ni samples was ascribed to the higher fluid retention capability of the latter and the tribofilm formed during sliding.


Metal-Containing Nanomaterials As Lubricant Additives: State-Of-The-Art And Future Development, Igor E. Uflyand, Vladimir A. Zhinzhilo, Victoria E. Burlakova Oct 2020

Metal-Containing Nanomaterials As Lubricant Additives: State-Of-The-Art And Future Development, Igor E. Uflyand, Vladimir A. Zhinzhilo, Victoria E. Burlakova

Friction

This review focuses on the effect of metal-containing nanomaterials on tribological performance in oil lubrication. The basic data on nanolubricants based on nanoparticles of metals, metal oxides, metal sulfides, nanocomposities, and rare-earth compounds are generalized. The influence of nanoparticle size, morphology, surface functionalization, and concentration on friction and wear is analyzed. The lubrication mechanisms of nanolubricants are discussed. The problems and prospects for the development of metal-containing nanomaterials as lubricant additives are considered. The bibliography includes articles published during the last five years.


Experimental Study On The Tribo-Chemical Smoothening Process Between Self-Mated Silicon Carbide In A Water-Lubricated Surface-Contact Reciprocating Test, Le Jin, Herbert Scheerer, Georg Andersohn, Matthias Oechsner, Dieter Hellmann Oct 2020

Experimental Study On The Tribo-Chemical Smoothening Process Between Self-Mated Silicon Carbide In A Water-Lubricated Surface-Contact Reciprocating Test, Le Jin, Herbert Scheerer, Georg Andersohn, Matthias Oechsner, Dieter Hellmann

Friction

Silicon carbide (SiC) can be tribo-chemically smoothened during a self-mated sliding procedure in the aqueous environment. As well reported in the point-contact tests, this smoothening process works well due to the abundant water as oxidant. After this smoothening process, the tribo-surface is well polished, a closely mated tribo-gap naturally forms, and an ultra-low friction state is built. However, water in the tribo-gap could be insufficient in industrial applications, e.g., the seal gap in mechanical seals. In this study, the tribo-chemical smoothening behavior in such environment was researched. A surface-contact reciprocating test was used to simulate the aqueous environment where water …


Water-Based Superlubricity In Vacuum, Chen Xiao, Jinjin Li, Lei Chen, Chenhui Zhang, Ningning Zhou, Tao Qing, Linmao Qian, Jiyang Zhang, Jianbin Luo Oct 2020

Water-Based Superlubricity In Vacuum, Chen Xiao, Jinjin Li, Lei Chen, Chenhui Zhang, Ningning Zhou, Tao Qing, Linmao Qian, Jiyang Zhang, Jianbin Luo

Friction

This study achieved water-based superlubricity with the lubrication of H3PO4 solution in vacuum (highest vacuum degree <10-4 torr) for the first time by performing a pre-running process in air before running in vacuum. The stable water-based superlubricity was sustainable in vacuum (0.02 torr) for 14 h until the test was stopped by the user for non-experimental factor. A further analysis suggested that the superlubricity may be attributed to the phosphoric acid-water network formed in air, which can efficiently lock water molecules in the liquid lubricating film even in vacuum owing to the strong hydrogen bond interaction. Such capability to lock water is strongly affected by the strength of hydrogen bond and environmental conditions. The realization of water-based superlubricity with H3PO4 solution in vacuum can lead to its application in space environment.


Tribological Performance Of Novel Nickel-Based Composite Coatings With Lubricant Particles, Ignacio Tudela, Andrew J. Cobley, Yi Zhang Oct 2020

Tribological Performance Of Novel Nickel-Based Composite Coatings With Lubricant Particles, Ignacio Tudela, Andrew J. Cobley, Yi Zhang

Friction

The present study is focused on the evaluation of the tribological performance of novel Ni/hBN and Ni/WS2 composite coatings electrodeposited from an additive-free Watts bath with the assistance of ultrasound. Lubricated and non-lubricated scratch tests were performed on both novel composite coatings and on standard Ni deposits used as a benchmark coating to have an initial idea of the effect of the presence of particles within the Ni matrix. Under lubricated conditions, the performance of the Ni/hBN composite coating was very similar to the benchmark Ni coating, whereas the Ni/WS2 behaved quite differently, as the latter did not only show …


Numerical Analysis Of Time-Varying Wear With Elastic Deformation In Line Contact, Wanglong Zhan, Ping Huang Oct 2020

Numerical Analysis Of Time-Varying Wear With Elastic Deformation In Line Contact, Wanglong Zhan, Ping Huang

Friction

Wear is an important factor for failures of mechanical components. Current research on wear is mainly focused on experiments while the numerical simulation of wear is hardly used owing to the complexities of the wear process. Explaining the effect of friction on the wear process is important, as it will lead to a deeper understanding of the evolution of wear. This study proposed a numerical method to expound the wear process in the contact between an elastic cylinder and a half-space simulating the ring-block tester. There are two difficulties during the calculation; one is that the contact shapes vary with …