| Description |
1 online resource (viii, 57 pages) : illustrations. |
| Physical Medium |
polychrome |
| Description |
text file |
| Series |
Biomedical & nanomedical technologies - concise monograph series
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Biomedical & nanomedical technologies.
|
| Note |
Co-published with American Society of Mechanical Engineers. |
| Bibliography |
Includes bibliographical references. |
| Contents |
1. Magnetic bearings for assist devices -- 1.1 Fundamentals of magnetic bearings -- 1.1.1 Considerations of a full magnetic suspension -- 1.1.2 Active magnetic bearing (AMB). |
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2. Structure of magnetic actuator -- 2.1 Properties of magnetic materials -- 2.2 Passive actuators -- 2.2.1 Typical passive configuration (radial passive bearing) -- 2.3 Active actuators -- 2.3.1 Typical radial -- 2.3.2 Flux biased magnetic bearings -- 2.4 Typical configuration of hybrid actuators -- 2.5 Electromagnetic coils -- 2.6 System configurations -- 2.6.1 Centrifugal vs. axial-flow configurations -- 2.6.2 Hydrodynamically assisted suspension -- 2.6.3 Motor assisted suspension. |
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3. Position sensors -- 3.1 Eddy current sensors -- 3.2 Inductance based sensors -- 3.3 Hall effect sensors -- 3.4 Optical sensors -- 3.5 Capacitive sensors -- 3.6 Self-sensing magnetic bearings. |
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4. Controller and electronics design -- 4.1 Design principle of one-axis suspension -- 4.2 Control laws -- 4.2.1 Proportional, integral, and derivative (PID) -- 4.2.2 Advanced control laws -- 4.3 Hardware -- 4.3.1 Analog-to-digital conversion and data acquisition -- 4.3.2 Processor -- 4.3.3 Power amplifier. |
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5. Performance considerations of magnetic bearings in VADs -- 5.1 System complexity -- 5.2 Weight and size -- 5.3 Power consumption -- 5.4 Physical disturbance rejection -- 5.5 Reliability and durability -- 5.5.1 Sensor failure -- 5.5.2 Wire and coil failure -- 5.5.3 Controller durability -- 5.6 Failure remediating measures -- 5.6.1 Manufacturing -- 5.6.2 Physical redundancy of components sensors and wires -- 5.6.3 Fault tolerant control -- 5.6.4 Touch-down bearings. |
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6. Specific device examples -- 6.1 Berlin Heart InCOR -- 6.2 Terumo Duraheart -- 6.3 WorldHeart Levacor -- 6.4 PediaFlow -- 6.5 WorldHeart MiFlow VAD -- 6.6 Heartware HVAD and mVAD -- 6.7 LEV-VAD -- 6.8 MitiHeart. |
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Conclusion. |
| Summary |
Magnetic bearings are mechatronic devices that produce contact-free electromagnetic force to support a load, such as a moving train or a spinning rotor. Compared to traditional bearings, magnetic bearings offer several advantages: no friction, low heat generation, no required lubrication, quiet operation, and fast and stable rotation. Because of these reasons, magnetic bearings have been used in rotary ventricular assist devices (VADs) to increase design life, reduce or eliminate material wear and bearing maintenance, as well as to increase biocompatibility by eliminating high fluid stresses and heat generation, both of which are associated with hemolysis, platelet activation and aggregation, and thrombus growth. In this chapter, magnetic bearings and their application in VADs are introduced. First, the operating principles of magnetic bearings are introduced. Typical structures of passive bearings, which are comprised solely of permanent magnets, and active magnetic bearings (AMB), which make use of electromagnets and position sensors to control the position of the rotor, are described. We include some description of all the components of a typical AMB system, including actuator, position sensor, controller, and amplifier, as well as different structures of electromagnet actuators, coils design, and iron selection. A range of position sensors, including those typically used in blood pumps, as well as self-sensing bearings are discussed. The basics of the hardware and the software (control laws) that comprise a typical magnetic bearing system are described. A section describes the performance considerations of magnetic bearings and the effect on the overall performance of an assist device that uses magnetic bearings. Lastly, the magnetic suspension of existing VADs with magnetic bearings are described: Berlin Heart INCOR, Heartware HVAD, WorldHeart Levacor and MiFlow, Terumo Duraheart, PediaFlow, MiTiHeart, and LEV-VAD. |
| Local Note |
eBooks on EBSCOhost EBSCO eBook Subscription Academic Collection - North America |
| Subject |
Biomedical materials.
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Biomedical materials. |
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Magnetic bearings.
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Magnetic bearings. |
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Cardiovascular instruments, Implanted.
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Cardiovascular instruments, Implanted. |
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Medical technology.
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Medical technology. |
| Genre/Form |
Electronic books.
|
| Added Author |
Cheng, Shanbao, author.
|
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Gomez, Arnold David, author.
|
| Added Title |
Magnetic bearings assist devices |
| Other Form: |
Print version: Day, Steven (Steven W.). Magnetic bearings for mechanical cardiac assist devices. New York, NY : ASME Press, [2015] 9780791860410 (DLC) 2015037208 (OCoLC)923793908 |
| ISBN |
9781606509203 (electronic book) |
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1606509209 (electronic book) |
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9781606509197 (print) |
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1606509195 (print) |
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9780791860410 |
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0791860418 |
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