다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

This chapter introduces the finite element method (FEM) as a tool for solution of classical electromagnetic problems. Although we discuss the main points in the application of the finite element method to electromagnetic design, including formulation and implementation, those who seek deeper understanding of the finite element method should consult some of the works listed in the bibliography section.

Introduction to the Finite Element Method

PREFACE. ACKNOWLEDGMENTS. PROLOGUE. 1 INTRODUCTION. 1.1 Historical Perspective. 1.2 Diagnostic and Prognostic System Requirements. 1.3 Designing in Fault Diagnostic and Prognostic Systems. 1.4 Diagnostic and Prognostic Functional Layers. 1.5 Preface to Book Chapters. 1.6 References. 2 SYSTEMS APPROACH TO CBM/PHM. 2.1 Introduction. 2.2 Trade Studies. 2.3 Failure Modes and Effects Criticality Analysis (FMECA). 2.4 System CBM Test-Plan Design. 2.5 Performance Assessment. 2.6 CBM/PHM Impact on Maintenance and Operations: Case Studies. 2.7 CBM/PHM in Control and Contingency Management. 2.8 References. 3 SENSORS AND SENSING STRATEGIES. 3.1 Introduction. 3.2 Sensors. 3.3 Sensor Placement. 3.4 Wireless Sensor Networks. 3.5 Smart Sensors. 3.6 References. 4 SIGNAL PROCESSING AND DATABASE MANAGEMENT SYSTEMS. 4.1 Introduction. 4.2 Signal Processing in CBM/PHM. 4.3 Signal Preprocessing. 4.4 Signal Processing. 4.5 Vibration Monitoring and Data Analysis. 4.6 Real-Time Image Feature Extraction and Defect/Fault Classification. 4.7 The Virtual Sensor. 4.8 Fusion or Integration Technologies. 4.9 Usage-Pattern Tracking. 4.10 Database Management Methods. 4.11 References. 5 FAULT DIAGNOSIS. 5.1 Introduction. 5.2 The Diagnostic Framework. 5.3 Historical Data Diagnostic Methods. 5.4 Data-Driven Fault Classification and Decision Making. 5.5 Dynamic Systems Modeling. 5.6 Physical Model-Based Methods. 5.7 Model-Based Reasoning. 5.8 Case-Based Reasoning (CBR). 5.9 Other Methods for Fault Diagnosis. 5.10 A Diagnostic Framework for Electrical/Electronic Systems. 5.11 Case Study: Vibration-Based Fault Detection and Diagnosis for Engine Bearings. 5.12 References. 6 FAULT PROGNOSIS. 6.1 Introduction. 6.2 Model-Based Prognosis Techniques. 6.3 Probability-Based Prognosis Techniques. 6.4 Data-Driven Prediction Techniques. 6.5 Case Studies. 6.6 References. 7 FAULT DIAGNOSIS AND PROGNOSIS PERFORMANCE METRICS. 7.1 Introduction. 7.2 CBM/PHM Requirements Definition. 7.3 Feature-Evaluation Metrics. 7.4 Fault Diagnosis Performance Metrics. 7.5 Prognosis Performance Metrics. 7.6 Diagnosis and Prognosis Effectiveness Metrics. 7.7 Complexity/Cost-Benefit Analysis of CBM/PHM Systems. 7.8 References. 8 LOGISTICS: SUPPORT OF THE SYSTEM IN OPERATION. 8.1 Introduction. 8.2 Product-Support Architecture, Knowledge Base, and Methods for CBM. 8.3 Product Support without CBM. 8.4 Product Support with CBM. 8.5 Maintenance Scheduling Strategies. 8.6 A Simple Example. 8.7 References. APPENDIX. INDEX.

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Intelligent Fault Diagnosis and Prognosis for Engineering Systems

Boundary Value Problems in Physics and Engineering By Frank Chorlton. Pp. 250. (Van Nostrand: London, July 1969.) 70s

Boundary value problems

random data analysis and measurement procedures is available in our digital library an online access to it is set as public so you can get it instantly. Our book servers spans in multiple countries, allowing you to get the most less latency time to download any of our books like this one. Merely said, the random data analysis and measurement procedures is universally compatible with any devices to read.

Random Data Analysis And Measurement Procedures

Real-time monitoring and control of mechanical face-seal dynamic behaviour

Dynamic stability is investigated for a mechanical seal configuration in which both seal elements are flexibly mounted to independently rotating shafts. The analysis is applicable to systems with both counterrotating and corotating shafts. The fluid film effects are modeled using rotor dynamic coefficients, and the equations of motion are presented including the dynamic properties of the flexible support. A closed-form solution for the stability criteria is presented for the simplified case in which the support damping is neglected. A method is presented for obtaining the stability threshold of the general case, including support damping. This method allows instant determination of the stability threshold for a fully-defined seal design. A parametric study of an example seal is presented to illustrate the method and to examine the effects of various parameters in the seal design upon the stability threshold. The fluid film properties in the example seal are shown to affect stability much more than the support properties. Rotors having the form of short disks are shown to benefit from gyroscopic effects which give them a larger range of stable operating speeds than long rotors. For seals with one long rotor, counterrotating operation is shown to be superior because the increased fluid stiffness transfers restoring moments from the short rotor to the long.

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Stability analysis of mechanical seals with two flexibly mounted rotors

Experimental Investigation of a New Concept Viscous Pump

This work presents the results of a Finite Element Analysis (FEA) used to simulate two-dimensional (2D) frictionless sliding between two interfering elasto-plastic cylinders. The materials for the cylinders are both modeled as elastic-perfectly plastic and follow the von Mises yield criterion. The FEA results in trends in the deformation, reaction forces, stresses, and net energy loss as a function of sliding distance. All these results are found to be related to the magnitude of vertical interference. In addition, equations representing the pattern followed by the residual deformation for each of these interference cases are shown. Contour plots of the von Mises stresses are also presented to show the formation and distribution of stresses with increasing plastic deformation as sliding progresses. This work shows that for the plastic loading cases the ratio of the vertical force to the horizontal reaction force is not zero at the point where the cylinders are perfectly aligned about the vertical axis. This work also presents empirical equations that relate the net energy loss due to sliding under an elasto-plastic deformation as a function of the sliding distance. In addition, a “load ratio” of the horizontal reaction force to the vertical one is defined. Although this is analogous to the common definition of the coefficient of friction between sliding surfaces, it just contains the effect of energy loss in plasticity. The values of the contact half-width are obtained for different vertical interferences as sliding progresses.Copyright © 2006 by ASME

A Finite Element Study of the Deformations, Forces, Stress Formations, and Energy Losses in Sliding Cylindrical Contacts

Contacting mechanical seals are load unbalanced. The unbalanced load (the difference between closing and opening forces) causes the seal faces to be in mechanical contact suppressing fluid pressure generation in the sealing dam. The two major concerns with contacting mechanical face seals are the wear rate of the faces and whether these faces will separate while in operation. These two modes of failure are directly related to the amount of initial compression (i.e., preset) in the bellows and the hydraulic loading. A new criterion for separation is presented based on a pragmatic model of the mechanics of contact. The separation speed derived herein is less conservative than that found more than two decades ago. The optimal speed which minimizes wear is determined to occur at the resonance frequencies of the system, thus providing guidelines for improved designs. Presented at the 44th Annual Meeting in Atlanta, Georgia May 1–4, 1989

Itzhak Green

Papers

Real-time monitoring and control of mechanical face-seal dynamic behaviour

Stability analysis of mechanical seals with two flexibly mounted rotors

Experimental Investigation of a New Concept Viscous Pump

A Finite Element Study of the Deformations, Forces, Stress Formations, and Energy Losses in Sliding Cylindrical Contacts

Separation Speed of Undamped Metal Bellows Contacting Mechanical Face Seals