Question

2) True or False (If statement is false, correct it so that it is true) a) Polymers make up an exciting class of biomaterials. Polyethylene is a wonderful example of a simple ceramic that can be used in multiple applications by modifying its chemical structure. It tends to be bioactive when used by itself as an implant, but it becomes even more bioactive when 10 vol% Calcium Carbonate is added to it. Teflon can be used as a vascular graft material due to its low coefficient of friction. This is achieved because C atoms are replaced by F atoms in its structure. Collagen is the premiere polymer that is produced in our bodies. There are about 15 types of collagen and this polysaccharide is very important in bone matrix formation and tissues and organs. b) A vacancy is a point defect that occurs when an atom is missing from a lattice position. A perfect metal crystal would exhibit ductile behavior. Amorphous crystals have long range order which can be measured by x-ray diffraction. X-ray crystal structure determination and the iridescent colors in nacre, butterfly wings, and beetle exoskeletons are caused by similar phenomena that involves the transmission of visible light. Metals tend to be harder than polymers, ceramics tend to be stronger than polymers, and metals tend to be harder than ceramics. Diamond is a unique material that exhibits metallic bonding. One of its more unusual features is that although it has a very high electrical conductivity, it is a poor conductor of heat. c) H bonding is a very important bond type in biological materials such as water and DNA. H bonding is responsible for the anomalous freezing behavior of water in which its density increases when it transforms from liquid to solid. It also plays a role in explaining why Geckos are able to cling to and run across atomically smooth surfaces. d) The microstructure of a metal sample that has been cooled from a melt would contain very large crystal grains on the interior and very small crystal grains on the exterior surface. This would be caused by differences in the heating rate where the exterior cools more slowly than the interior. e) The (100) plane physically intersects the Y and Z axes and it is perpendicular to the (010) plane and parallel to the (020) plane.

Answer 1

a) False

Polymers make up an exciting class of biomaterials. Polyethylene is a wonderful example of a simple plastic that can be used in multiple applications by modifying its chemical structure. It tends to be inactive when used by itself as an implant, but it becomes even more harder when 10 vol% Calcium Carbonate is added to it. Teflon can be used as a vascular graft material due to its low coefficient of friction. This is achieved because H atoms are replaced by F atoms in its structure. Collagen is the premiere polymer that is produced in our bodies. There are about 15 types of collagen and this protein is very important in bone matrix formation and tissues and organs.

b) False

A vacancy is a point defect that occurs when an atom is missing from a lattice position. A perfect metal crystal would exhibit ductile behavior. Amorphous crystals lack long range order which can be measured by x-ray diffraction. X-ray crystal structure determination and the iridescent colors in nacre, butterfly wings, and beetle exoskeletons are caused by similar phenomena that involves the diffraction of light. Metals tend to be harder than polymers, ceramics tend to be harder than polymers, and metals tend to be stronger than ceramics. Diamond is a unique material that exhibits strong covalent bonding. One of its more unusual features is that although it has a very high electrical insulation, it is a good conductor of heat.

C)False

H bonding is a very important bond type in biological materials such as water and DNA. H bonding is responsible for the anomalous freezing behavior of water in which its density decreases when it transforms from liquid to solid. It also plays a role in explaining why Geckos are able to cling to and run across atomically smooth surfaces.

d)True