A Complex Network Theory for Cascading Failure Problem in an Interdependent Food Supply Chain Network

Yan Yan,Wei Xu 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.9

Thermodynamic Analysis on Heat Recovery System of Hermetic Gas Hood for Paper Machine

Yan Yan,Dong Jixian 한국펄프·종이공학회 2020 펄프.종이기술 Vol.52 No.2

The working condition of hot air exchange system dramatically affects the operational status of the paper machine dryer, energy saving efficiency and paper quality of dryer section. After analyzing the heat recovery method and energy-saving effect of the closed air hood, it is found that the current process is limited by the design of the heat exchanger and the control system, and usually the preheated fresh air in the first-stage heat recovery device only recovers the sensible heat in the exhaust air of the air hood. Therefore, the common heat recovery process has been adjusted in this paper. The fresh air is firstly heated by latent heat with relatively low temperature in the exhaust gas, and then the sensible heat with relatively high temperature in the exhaust gas is recovered. The energy saving effect is calculated through an example. The calculation results show that this process can save about 20% energy compared with the original process.

Modeling of micro-annulus propagation along cementing interface in stimulated horizontal wellbore

Yan Yan,Guan Zhichuan,Yan Weijun 한국자원공학회 2021 Geosystem engineering Vol.24 No.5

Once there are micro-annulus at cementing interfaces in the process of reservoir stimulation, it is easy to form fluid channeling in the later development. Fluid channeling reduces the efficiency of reservoir development and even the service life of oil and gas wells. Based on the characteristics of ‘multi-stage’ in stimulated reservoir volume, a mathematical model was set up to calculate the interface debonding length driven by hydraulic pressure. The propagation process of microannulus in stimulated reservoir volume was also analyzed. The results show that the propagation speed of the micro-annulus gradually slows down with the progress of fracturing. Meanwhile, the debonding azimuth of the micro-annulus and the cement elastic modulus have dominant effects on the propagation length. It is recommended that the setting position of the packer be outranged from the debonding area of the cementing interface in the design of the stimulated reservoir volume scheme to avoid fluid channeling between the stages. This study can predict the unsealing length of cement sheath during hydraulic fracturing as a reference for the optimization of fracturing parameters.

The Influence of Nozzles on Bottomhole Flow Field of Dual-diameter PDC Bit

Yan Yan,Zhichuan Guan,Cai Yang,Han Yan 한국유체기계학회 2020 International journal of fluid machinery and syste Vol.13 No.1

In order to improve cleaning efficiency of dual-diameter PDC bit, the total flow area, inclination angle and azimuth angle of bit’s pilot and reaming nozzles were analyzed. By numerical simulation, the velocity, pressure and particle distribution of bottomhole are obtained. The results show that low pressure area of pilot downhole decreases while low pressure of reamer downhole increases with the increase of total flow area. The mud velocity of central bottomhole has the negative relationship with inclination angle and positive relationship with azimuth angle. Best cleaning efficiency can be achieved when total flow area is 12 ㎠, inclination angles of pilot and reamer are respectively 15° and 25°, and azimuth angles of pilot and reamer are respectively 60° and 30°.

Study on Paper Drying Rate Based on Lattice Boltzmann Method

Yan Yan,Pan Jiangli,Dong Jixian,Sun Jian 한국펄프.종이공학회 2022 펄프.종이기술 Vol.54 No.1

The lattice Boltzmann method and the law of conservation of kinetic energy were used to simulate and analyze moisture transfer during the drying process. The effects of paper porosity, paper basis weight, drying temperature and hot air velocity on the drying char- acteristic curve were investigated. The results show that porosity has a strong influence on the drying characteristic curve in the constant drying stage but less of an influence in the falling rate drying stage. Different paper basis weights have a significant effect on drying characteristics. The greater the weight is, the longer the drying time is. Increasing the drying temperature and hot air velocity could shorten the drying time, but the effect became weaker as these parameters were increased. These results indicated that the drying efficiency cannot be significantly improved by increasing the temperature and flow rate.

Motion behavior research of liquid micro-particles filtration at various locations in a rotational flow field

Yan Yan,Yuanzai Lin,Jie Cheng,Zhonghua Ni 국제구조공학회 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.62 No.2

This study presents a particle-wall filtration model for predicting the particle motion behavior in a typical rotational flow field-filtration in blower system of cooker hood. Based on computational fluid dynamics model, air flow and particles has been simulated by Lagrangian-particle/ Eulerian-gas approaches and get verified by experiment data from a manufacturer. Airflow volume, particle diameter and local structure, which are related to the particle filtration has been studied. Results indicates that: (1) there exists an optimal airflow volume of 1243 m3/h related to the most appropriate filtration rate; (2) Diameter of particle is the significant property related to the filtration rate. Big size particles can represent the filtration performance of blower; (3) More than 86% grease particles are caught by impeller blades firstly, and then splashed onto the corresponding location of worm box internal wall. These results would help to study the micro-particle motion behavior and evaluate the filtration rate and structure design of blower.

Thermodynamic Performance Analysis of New Paper Machine Air Hood Heat Recovery System

Yan Yan,Wang Weichao,Pan Zhao 한국펄프·종이공학회 2022 펄프.종이기술 Vol.54 No.6

In this paper, a new heat recovery system of hot air hood of paper machine is proposed, the thermodynamic model of the system is established, and the effect of different thermal parameters on the heat recovery efficiency of the system is studied. The results indicate that both the recovered energy and the proportion of exhaust air passing through the latent heat exchanger attenuate as fresh air temperature increase and fresh air moisture content decrease. The system heat recovery increasing with rising of exhaust temperature. Exhaust temperature and exhaust relative humidity have different effects on sensible and latent heat recovery. The maximum value of proportion of exhaust air passing through latent heat exchanger appears when the exhaust relative humidity is 35.8%. Overall, the fresh air temperature and the exhaust relative humidity have great influence on the heat recovery efficiency.

Adaptive Asymptotic Tracking Fault-tolerant Control of Uncertain Nonlinear Systems with Actuator Failures and Event-triggered Inputs

Yan Yan,Libing Wu,Nannan Zhao,Ruiyan Zhang 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.3

This paper is concerned with the problem of adaptive asymptotic tracking fault-tolerant control (FTC) for uncertain nonlinear systems with actuator faults and event-triggered inputs. Firstly, fault-tolerant controller is designed to effectively compensate the unknown actuator failures by constructing the proper parameter updated laws. Then, the event-triggered strategy based on the relative threshold method is applied to the proposed adaptive fault-tolerant controller. Furthermore, it is proved that all the closed-loop signals are uniformly bounded and the tracking error can asymptotically converge to zero. Finally, the simulation results are given to demonstrate the effectiveness of the presented control scheme.

FSSPCM: Fuzzy Publication of Data for Privacy Preserving

Yan Yan,Xiaohong Hao,Wanjun Wang 보안공학연구지원센터 2016 International Journal of Security and Its Applicat Vol.10 No.11

The rapid development of information technology makes it convenient to release, collect, store and analyze various types of data. At the same time, how to protect the privacy of individual and prevent disclosure of sensitive information during data publication has become a major challenge. K-anonymity method is the most widely used privacy protection model and has been well researched. However, generalization and suppression operations used in K-anonymity methods require high computational effort and cause excessive loss of original information, which will greatly reduce the availability of data after publishing. The paper proposed a transformation algorithm for privacy preserving data publishing based on fuzzy semantic set pair cloud model (FSSPCM). It transforms the sensitive attributes into the form of fuzzy semantic values, and privacy of individual has been maintained because exact values cannot be predicted after data publishing. In order to enhance the availability of data after publishing, semantic distinction (SD) and reserve degree (RD) are designed to reflect relationships between original data and fuzzy semantic information after transformation according to different characteristics of numerical sensitive attributes and categorical sensitive attributes. Experiments and analysis demonstrate the effectiveness of the proposed method both on numerical and categorical sensitive attributes. Classification performed on original and transformed information proves the proposed method maintains higher clustering similarity after fuzzy transformation, which will provide better availability for data mining and other processing.

Research on the Development of China “Supermarket-Farmer Direct Purchase” Mode

Yan Yan,강태원 한국프랜차이즈경영학회 2013 프랜차이즈경영연구 Vol.4 No.1

The realization of agricultural modernization, the solving of the “three rural” issue as well as the increment of farmers’ income is one of China’s top priority. Thus, under the support and encouragement of government’s relevant policies, China has introduced the “Supermarket-Farmer Direct Purchase” which is a new mode for the supply of agricultural products. This is an innovative of agricultural products circulation mode, and the comprehensive promotion will help supermarkets get cheap goods directly from the hands of farmers, thus forming price competitiveness; farmers can also get profits and subsidies from supermarkets which can eliminate middlemen’s profit, thus increasing their revenue; consumers can both get a guarantee of food safety and save expenses, and the win-win situation for the supermarkets, farmers, and consumers will be achieved. However, the dilemma between “farmers having difficulty in selling” and “supermarkets having difficulty in buying” is still frequent. So in this thesis, through theoretical research and situation analysis, each relevant part of the “Supermarket-Farmer Direct Purchase” mode will be studied as a whole. Moreover, effectiveness will be evaluated and relevant problems will be identified. Then, based on foreign experience and our national conditions, new modes and advice will be provided for users in different circumstances.