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Generalized stress field in granular soils heap with RayleigheRitz method

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Journal of Rock Mechanics and Geotechnical Engineering 2017年第1期9卷 135-149页

作者： Gang bi CH2M Inc. Englewood USA Chongqing Titan Architects-Multi-Disciplinary Practice Co. Chongqing China

The stress field in granular soils heap(including piled coal) will have a non-negligible impact on the settlement of the underlying soils. It is usually obtained by measurements and numerical *** the former method is not reliable as pressure cells instrumented on the interface between piled coal and the underlying soft soil do not work well, results from numerical methods alone are necessary to be doubly checked with one more method before they are extended to more complex cases. The generalized stress field in granular soils heap is analyzed with Rayleighe Ritz method. The problem is divided into two cases: case A without horizontal constraint on the base and case b with horizontal constraint on the base. In both cases, the displacement functions u(x, y) and v(x, y) are assumed to be cubic polynomials with 12 undetermined parameters, which will satisfy the Cauchy’s partial differential equations, generalized Hooke’s law and boundary equations. A function is built with the Rayleighe Ritz method according to the principle of minimum potential energy, and the problem is converted into solving two undetermined parameters through the variation of the function, while the other parameters are expressed in terms of these two parameters. by comparison of results from the Rayleighe Ritz method and numerical simulations, it is demonstrated that the Rayleighe Ritz method is feasible to study the generalized stress field in granular soils heap. Solutions from numerical methods are verified before being extended to more complicated cases.

关键词： Generalized stress field Rayleighe Ritz method Stress depression Variation of the function Principle of minimum potential energy

The study of disturbance sources energy size identification based on free energy theory

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Science China(Technological Sciences) 2018年第2期61卷 242-249页

作者： bi tianshu qin junda state key laboratory of alternate electrical power system with renewable energy sources north china electric power universityBeijing 102206China

The influence of power system disturbance on safety and stability is serious. Therefore, it is very important to identify the disturbance quickly and accurately. However, until now there is no unilbrm standard evaluation of disturbances on the energy impact strength, also no appropriate method to quantitatively and quickly assess the size of the disturbance energy. In this paper, the relationship between energy enthalpy and free energy in thermodynamics field is introduced into the description of disturbance free energy. And a new method based on energy entropy theory is proposed. In order to analyze the energy characteristics of various types of disturbances in power systems, an amended method of energy entropy is proposed. The free energy of each disturbance is described. Finally, the proposed theory is validated using the standard IEEE 39-bus system. The disturbance free energy is calculated under 5 kinds of disturbances. The proposed method provides a new idea to analyze the disturbance propagation and describe the impact strength of disturbance.

关键词： free energy disturbance identification energy identification energy entropy

First discovery of coesite in eclogite from East Kunlun, northwest China

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Science bulletin 2018年第23期63卷 1536-1538页

作者： Hengzhe bi Shuguang Song Jinlong Dong Liming Yang Shengsheng Qi Mark b.Allen MOE Key Laboratory of Orogenic belt and Crustal Evolution School of Earth and Space SciencesPeking UniversityBeijing 100871China Qinghai bureau of Geological Survey Xining 810012China Department of Earth Sciences Durham UniversityDurham DH13LEUK

Ultrahigh-pressure (UHP)metamorphism plays important roles in continental *** of this process has been enhanced by the discovery of coesite and micro-diamond from supracrustal rocks [1].Such UHP mineral inclusions provide unequivocal evidence that the least dense part of the lithosphere can be buried to 100-150km or more,and then returned to the ***,an ultrahigh-pressure polymorph of SiO2stable above 2.7GPa at metamorphic temperatures,is one of the most important index minerals for UHP metamomhism [1,2].

关键词： Cobalt feldspar East Kunlun eclogite

Fault Feature Extraction of Diesel Engine based on bispectrum Image Fractal Dimension

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Chinese Journal of Mechanical Engineering 2018年第2期31卷 216-226页

作者： Jian Zhang Chang-Wen Liu Feng-Rong bi Xiao-bo bi Xiao Yang State Key Laboratory of Engines Tianjin University

Fault feature extraction has a positive effect on accurate diagnosis of diesel engine. Currently, studies of fault feature extraction have focused on the time domain or the frequency domain of signals. However, early fault signals are mostly weak energy signals, and time domain or frequency domain features will be overwhelmed by strong back?ground noise. In order consistent features to be extracted that accurately represent the state of the engine, bispectrum estimation is used to analyze the nonlinearity, non?Gaussianity and quadratic phase coupling(QPC) information of the engine vibration signals under different conditions. Digital image processing and fractal theory is used to extract the fractal features of the bispectrum pictures. The outcomes demonstrate that the diesel engine vibration signal bispectrum under different working conditions shows an obvious differences and the most complicated bispectrum is in the normal state. The fractal dimension of various invalid signs is novel and diverse fractal parameters were utilized to separate and characterize them. The value of the fractal dimension is consistent with the non?Gaussian intensity of the signal, so it can be used as an eigenvalue of fault diagnosis, and also be used as a non?Gaussian signal strength indicator. Consequently, a symptomatic approach in view of the hypothetical outcome is inferred and checked by the examination of vibration signals from the diesel motor. The proposed research provides the basis for on?line monitoring and diagnosis of valve train faults.

关键词： Engine fault diagnosis bispectrum image processing Fractal Signal processing

ASSESSMENT OF HEAVY METALS IN HYDROCHAR PRODUCED bY HYDROTHERMAL CARbONIZATION OF DAIRY MANURE

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Frontiers of Agricultural Science and Engineering 2023年第3期10卷 437-447页

作者： b.brian HE Zheting bi Lide CHEN Chemical&biological Engineering College of EngineeringUniversity of Idaho875 Perimeter Drive MS 0904MoscowID 83844USA. Shape Therapeutics 700 Dexter Avenue NorthSL15SeattleWA 98109USA Soil and Water Systems Twin Falls Research and Extension CenterUniversity of Idaho315 Falls Ave.Twin FallsID 83303USA

Hydrochar produced from dairy manure is a regulated biosolid if being promoted for agricultural applications thus must have the properties that comply with all environmental standards and government regulations,including the levels of heavy metals(HMs).In this study,systematic research was conducted on HM levels in hydrochar from dairy manure and on the effects of processing conditions,including processing temperature(180–255℃),holding time(30–120 min)and solid content of manure slurry(2%–15%),through a central composite design and statistical *** was found that HMs can be retained in hydrochar,ranging from 40%to 100%.The processing temperature and solid content in the feed were the most influential process parameters that affected HMs retention in *** analysis showed that there was no single optimal point to minimize HMs retained in hydrochar,but there were minimization points at given processing time and solid *** HMs concentrations were higher in hydrochar than those initially in dairy manure but were greatly below the thresholds as set by the US government ***,hydrochar is feasible for use as a phosphorus-enriched organic fertilizer and/or soil amendment for agricultural applications without serious concerns about HMs it might contain.

关键词： heavy metals dairy manure hydrochar hydrothermal carbonization waste management

Dispersion and Damage of Carbon Nanotubes in Carbon Nanotube/7055Al Composites During High-Energy ball Milling Process

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Acta Metallurgica Sinica(English Letters) 2021年第2期34卷 196-204页

作者： S.bi b.L.Xiao Z.H.Ji b.S.Liu Z.Y.Liu Z.Y.Ma Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of Sciences72 Wenhua RoadShenyang 110016China School of Material Science and Engineering University of Science and Technology of China72 Wenhua RoadShenyang 110016China AVIC Manufacturing Technology Institute Beijing 100024China

High-energy ball milling(HEbM)combined with powder metallurgy route was used to fabricate carbon nanotube(CNT)reinforced 7055 Al *** powder morphology evolution processes(HEbM-1 and HEbM-2)were designed to investigate the dispersion and damage of CNTs during HEbM ***-1 evolution process involved powder fl attening,cold-welding and fracture,while HEbM-2 evolution process consisted of powder fl attening and *** HEbM-1,the repetitive fracture and cold-welding process was effective for dispersing ***,the powder fl attening process in HEbM-2 was unsuccessful in dispersing CNTs due to two reasons:(1)the thickness of fl aky Al powders exceeded the critical value,and(2)the clustered CNTs embedded in fl aky Al powders could not be *** of the broadening of D band and the appearance of a new defect-related D’band,product of I D/I G and full width half maximum of D band,rather than I D/I G,was used to evaluate the actual damage of *** indicates that the damage of CNTs was severe in powder fl attening and fracture stages,while the damage of CNTs was small in powder cold-welding stage.

关键词： Metal matrix composites Carbon nanotubes Powder evolution Dispersion and damage Powder metallurgy

Integration of α-fairness with DEA based resource allocation model

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Journal of Systems Engineering and Electronics 2014年第6期25卷 1027-1036页

作者： Gongbing bi Hailing Wang Jingjing Ding School of Management University of Science and Technology of China School of Management Hefei University of Technology

How to allocate a resource efficiently and fairly attracts the attention of both researchers and practitioners. Data envelopment analysis（DEA） has been brought to bear on its solution. The existing literature applies Gini coefficient to measure the fairness in the resource allocation process. However, the Gini coefficient is inapplicable in many applications. This paper proposes a novel centralized resource allocation model based on DEA that considers both the efficiency and the fairness. This paper adopts a notion of fairness, namely α-fairness that is well studied in welfare economics and is of practical significance. The new model integratesα-fairness with DEA to support resource allocation decisions. It aids decision makers in making a trade-off between the efficiency and the fairness. An illustrative application is used to validate the proposed approach.

关键词： data envelopment analysis(DEA) resource alloca-tion efficiency fairness α-fairness Gini coefficient

Effect of algal flocculation on dissolved organic matters using cationic starch modified soils

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Journal of Environmental Sciences 2016年第7期28卷 177-184页

作者： Wenqing Shi Lei bi Gang Pan Research Center for Eco-Environmental Sciences Chinese Academy of Sciences School of Animal Rural and Environmental Sciences Nottingham Trent University

Modified soils（MSs） are being increasingly used as geo-engineering materials for the sedimentation removal of cyanobacterial blooms. Cationic starch（CS） has been tested as an effective soil modifier, but little is known about its potential impacts on the treated *** study investigated dissolved organic matters in the bloom water after algal removal using cationic starch modified soils（CS-MSs）. Results showed that the dissolved organic carbon（DOC） could be decreased by CS-MS flocculation and the use of higher charge density CS yielded a greater DOC reduction. When CS with the charge density of 0.052, 0.102 and0.293 meq/g were used, DOC was decreased from 3.4 to 3.0, 2.3 and 1.7 mg/L, *** excitation–emission matrix fluorescence spectroscopy and UV254 analysis indicated that CS-MS exhibits an ability to remove some soluble organics, which contributed to the DOC reduction. However, the use of low charge density CS posed a potential risk of DOC increase due to the high CS loading for effective algal removal. When CS with the charge density of 0.044 meq/g was used, DOC was increased from 3.4 to 3.9 mg/L. This study suggested, when CS-MS is used for cyanobacterial bloom removal, the content of dissolved organic matters in the treated water can be controlled by optimizing the charge density of CS. For the settled organic matters, other measures（e.g., capping treatments using oxygen loaded materials） should be jointly applied after algal flocculation.

关键词： Cyanobacterial bloom Cationic starch Modified soil Charge density Dissolved organic carbon

Friction predication on pin-to-plate interface of PTFE material and steel

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Friction 2019年第3期7卷 268-281页

作者： Zhuming bi Donald W.MUELLER Depatment of Civil and Mechnical Engineering Purdue University Fort WayneFort Wayne2101EUSA School of Mechanical and Electrical Engineering GuangDong University of TechnologyGuangzhou510006China

In this paper,the friction behavior at a pin-to-plate interface is *** pin and plate are made of Polytetrafluoroethylene(PTFE) and steel,respectively,and there is a reciprocating motion at the *** 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 *** models have been developed to represent intrigued friction behaviors affected by various factors such as pin geometrics and finishes,lubrication conditions,and reciprocating *** test data from experiments is used to verify the effectiveness of the proposed models.

关键词： pin-to-plate friction wear coefficient of frictions PTFE sealing finite element analysis