Chapter 17, Problem 1

Chapter 17, Problem 1 Explain the difference between a biomaterial and biological materials.Chapter 17, Solution 1 Biological materials are materials produced by biological systems. These are the materials naturally occurring in our body. Biomaterials are those materials that are used to make anything that is implanted into the body.Chapter 17, Problem 2 Explain why bone may be classified a composite material.Chapter 17, Solution 2 Bone is made up of inorganic material (calcium phosphate) and organic material (collagen) arranged in a specific pattern. Thus, bone is classified as a composite material.Chapter 17, Problem 3 Explain the function of cancellous bone?Chapter 17, Solution 3 Cancellous bone is porous in nature. It has higher yield strain than coortical bone and is abundant at the ends of long bones. Therefore, it absorbs the energy at the ends of the bone during shock loading. It also houses bone marrow.Chapter 17, Problem 4 Explain different modes of bone fracture.Chapter 17, Solution 4 The bone can fracture when loaded in tension. When a muscle contracts aggressively, it might subject the tendon insertion point to tension, and the bone can fail in tension. This is called avulsion. The bone can fracture in compression specifically during impact loading. For example, falling on the side can subject the hip joint into compression, and the bone might fail. Bone can fail in bending as during the boot-top fracture. Bone can also fail in torsion when the opposite ends of long bones are rotated in different directions.Chapter 17, Problem 5 Define biocompatibility and Explain why it is important.Copyright © McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education.680 Solutions Manual for Foundations of Materials Science and Engineering 7th Edition By William Smith, Javad Hashemi (All Chapters 1-17, 100% Original Verified, A+ Grade)

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Chapter 17, Solution 5 The corrosion resistance, non-toxicity, and chemical stability of a biomaterial inside the human body defines its biocompatibility. Biocompatibility is a very important characteristic of a biomaterial. The material that is not biocompatible can disintegrate inside the body causing problems with health and the mechanical failure of the medical device.Chapter 17, Problem 6 What is stress shielding? How can it be avoided?Chapter 17, Solution 6 When a bone implant system is loaded, there are chances that the implant takes the majority of load and shield the bone from the load. This is called stress shielding. It can be avoided by choosing the implant material that has the modulus of elasticity closer to that of bone and also by using biodegradable implants.Chapter 17, Problem 7 What are biopolymers?Chapter 17, Solution 7 Biopolymers are those polymers that are biocompatible and can be used in biomedical applications as a biomaterial.Chapter 17, Problem 8 What properties of biopolymers make them suitable for biomedical applications?Chapter 17, Solution 8 Biopolymers have low mass and can be easily formed into complex shapes. Their properties can be controlled during manufacturing, and their biocompatibility can be maximized. They can also be made biodegradable. These properties make biopolymers very attractive as biomaterials.Chapter 17, Problem 9 How are polymers used in cardiovascular applications?Chapter 17, Solution 9 Biopolymers are used for the sewing ring of artificial heart valves. They are also used for vascular grafts to bypass severely clogged coronary arteries. They are used in the membranes of blood oxygenators during cardiac surgeries. Biopolymers are also used in artificial hearts.Copyright © McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education.

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Chapter 17, Problem 10 How are polymers used in opthalmic applications?Chapter 17, Solution 10 Hydrogel, a biopolymer is used to make soft contact lenses conform to the shape of the cornea. PMMA is used to make hard lenses used as intraocular implants.Chapter 17, Problem 11 How are polymers used in drug delivery systems?Chapter 17, Solution 11 The matrix of biodegradable polymer such as PGA contains the drug and is implanted at a location of interest inside the body. As the biodegradable polymer degrades, it releases the drug into the blood stream.Chapter 17, Problem 12 Discuss the use of polymers in orthopaedic applications.Chapter 17, Solution 12 PMMA, a biopolymer is used as a bone cement to fill the gap between bone and implant. It is also used as bearing surfaces in joint prosthesis such as hip implants. However, since these polymers are relatively soft, they are susceptible to abrasive wear.Chapter 17, Problem 13 What are some useful properties of bioceramics?Chapter 17, Solution 13 Bioceramics are highly biocompatible (very inert) and have superior wear resistance, corrosion resistance, high stiffness, and low friction.Chapter 17, Problem 14 Explain the important properties of alumina that makes it attractive for biomedical use.Chapter 17, Solution 14 High-purity alumina has excellent corrosion resistance, high wear resistance, high strength, low friction and is biocompatible. It can also be used as a porous coating above a metal substrate allowing for bone ingrowth.Copyright © McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education.

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Chapter 17, Problem 15 What are the advantages of titanium alloys in biomedical applications?Chapter 17, Solution 15 Titanium alloys have excellent corrosion resistance as they form a titanium oxide film over the surface.They also have low modulus of elasticity and, thus, minimize the chances of stress shielding by transferring the loads to the bone.Chapter 17, Problem 16 How are nanocrystalline ceramics different from conventional ceramics?Chapter 17, Solution 16 Traditional ceramics are brittle. Nanocrystalline ceramics are as strong as traditional ceramics but are also ductile, so are tougher than traditional ceramics. They are also found to be osteoconductive.Chapter 17, Problem 17 What are the advantages of composites in biomedical applications?Chapter 17, Solution 17 Composite materials have the advantage of being able to offer a combination of properties often required to match the needs of biomedical applications. We can combine two or more materials and get the best of the properties of both the materials. Since biological materials are composites, composite biomaterials can closely mimic their properties.Chapter 17, Problem 18 Explain how composite materials can be used to fix bone fracture.Chapter 17, Solution 18 A composite material made up of high-density PE and hydroxyappetite can be used to replace natural bone (bone graft). Carbon fiber-reinforced PMMA, PBT, and PEEK can be used to produce fracture- fixation devices with higher flexibility and adequate strength. Composite fracture fixation plates, made of poly-L-lactide reinforced with u-HA particles, are biodegradable and have the modulus of elasticity close to that of cortical bone.Chapter 17, Problem 19 What are the main types of corrosion in biometals?Copyright © McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education.683

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