Term
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Definition
| the study of the mechanical laws relating to the movement or structure of living organisms |
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Term
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Definition
| synthetic material used to replace part of a living system or to function in intimate contact with a living issue (also read various definitions given by other authors in the text) |
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Term
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Definition
| a material praduced by a living organism |
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Term
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Definition
| acceptance of an artifical implant by the surrounding tissues and by the body as a whole. the biomaterial must not be degrated by the body environment, and its presence must not harm tissues, organs, or systems. if the biomaterial is designed to be degraded, then the products of degradation should not harm the tissues or organs |
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Term
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Definition
| (Center for Devices and Radiological Health): branch of the FDA that administers medical devices-related regulations |
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Term
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Definition
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Term
| ETO (ethylene oxide gas, (CH2)2O) |
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Definition
| a flammale toxic gas used as a sterilization agent |
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Term
| FDA (Food and Drug Administration) |
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Definition
| government agency regulating testing, production, and marketing of food and drugs including medical devices within the United States |
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Term
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Definition
| (finite-element modeling/analysis): stress and strain analysis of a structural body using computer software. The object is divided and the distribution of stresses and strains calculated |
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Term
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Definition
| the emission of energy as short electromagnetic waves that cause ionization. The radioactive isotope 60CO is an effective source of the radition. To be effective for sterilization, about 10^6 Gy (J/Kg) is needed |
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Term
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Definition
| (Good Manufacturing Practices): medical devices are made in a clean room condition to prevent any contamination. Such practices are required by the FDA for manufacture of implants |
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Term
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Definition
| Lysis (disdsolution) of erythrocytes in blood with the release of hemoglobin |
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Term
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Definition
| (International Standard Organization): ISO9000 is a set of standards related to medical devices necessary to maintain an efficiant and quality system. A standard focuses on controlling organizations rather than specific requirements for final products. ASTM 13.01 focuses on specific products in the United States |
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Term
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Definition
| a microscopic hollow sphere, especially of a protein or synthetic polymer |
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Term
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Definition
| the capacity of a chemical or physical agent to cause permanent genetic alterations |
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Term
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Definition
| (Premarket Approval): some medical devices can be approved by the FDA without extensive tests required by the FDA through MDE (medical divice exemptions) 510K |
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Term
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Definition
| caused or produced by combustion or the application of heat-inducing fever |
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Term
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Definition
| making (an organism) abnormally sensitive to a foreign substance, such as a metal |
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Term
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Definition
| denoting the part of the circulatory system concerned with transportation of oxygen to and crbon dioxide from the body in general |
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Term
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Definition
| generation of new tissue using living cells, optimally the patient's own cells, as building blocks, coupled with biodegradable materials as a scaffold |
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Term
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Definition
| materials obtained by combining two or more materials at a scale larger than the atomic/molecular, e.g., nanoscale, microscale, or macroscale, taking advantage of salient features of each material. An example is (high-strength) fiber-reinforced epoxy resin |
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Term
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Definition
| polymers made from two or more homopolymers; can be obtained by grafting, block, alternating, or random attachment of the other polymer segment |
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Term
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Definition
| bonding of atoms or molecules by sharing valence electrons |
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Term
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Definition
| rubbery materials. the restoring force comes from uncoiling or unkinking of coiled or kinked molecular chains. they can be highly stretched |
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Term
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Definition
| the difference in volume occupied by the crystalline state (minimum) and noncrystalline state of material for a given temperature and a pressure |
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Term
| Glass Transition Temperature |
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Definition
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Term
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Definition
| a secondary bonding through dipole interactions in which a hydrogen ion is one of the dipoles |
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Term
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Definition
| bonding of atoms or molecules through electrostatic interatction of positive and negative ions |
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Term
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Definition
| defects created in a perfect (crystalline) structure by vacancy, interstitial, and substitutional atoms by the introduction of an extra plane of atoms (dislocations) or by mismatching at the crystals during solidification (grain boundries) |
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Term
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Definition
| the spacing ofatoms in a crystal lattice. for example, in cubic crystal systems all the lattice constants are the same, i.e., a=b=c, so that the atomic apacing is the same in each prinicipal direction |
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Term
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Definition
| bonding of atoms or molecules through loosly bound valence electrons around positive metal ions |
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Term
| minimum radius ration (r/R) |
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Definition
| ration between the radius of a smaller atom to be fitted into the space among the larger atom's radius based on geometric consideration |
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Term
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Definition
| the (atomic) volume per unit volume (or space) |
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Term
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Definition
| substance made of small molecules, mixed with (amorphous) polymers to make the chains slide more easily past each other, making the polymer less rigid |
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Term
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Definition
| structure of a material that is an aggregate of single crystals (grains) |
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Term
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Definition
| electrical conductivity of a material lies between that of a conductor and an insulator. there is an energy band gap of the order of 0.1 eV (Sn) to 6eV (C, diamond), which governs the conductivity and its dependence on temperature |
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Term
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Definition
| solid that contains both crystalline and noncrystalline regions; for example, in polymers due to thier long-chain molecules |
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Term
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Definition
| arrangement of asymmetrical side groups along the backbone chain of polymers; groups could be distributed at random (atactic), on one side (isotactic), or alternating (syndiotactic) |
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Term
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Definition
| smallest repeating unit of a space lattice representing the whole crystal structure |
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Term
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Definition
| outermost (shell) electrons of an atom |
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Term
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Definition
| secondary bonding arising through the fluctuating dipole-dipole interactions |
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Term
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Definition
| thermoplastic linear polymers synthesized by free radical polymerization of vinyl monomers having a common structure of CH2=CHR |
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Term
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Definition
| crosslinking of rubbers by sulfer |
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Term
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Definition
| joining of two different materials |
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Term
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Definition
| physical attachment of foreign material (usually gas) on a surface |
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Term
| Boltzmann superposition principle |
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Definition
| effect of a compound cause is the sum of the effects of individual causes. this is the statement of linearity for viscoelastic materials |
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Term
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Definition
| chemical attachment of foreign material (usually gas) on a surface |
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Term
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Definition
| joining of identical materials |
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Term
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Definition
| angle made when a drop of liquid spreads over a solid surface. it is governed by the balance of surface tension at various interfaces |
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Term
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Definition
| type of integral equation used in the analysis of viscoelastic materials |
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Term
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Definition
| increase of strain with time in viscoelastic materials under constant stress |
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Term
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Definition
| stress level below which the material will not fail by cyclic fatigue loading no matter how many cycles (a practical limit is often chosen as 10^7 cycles) |
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Term
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Definition
| stress calculated beased on its original cross-sectional area |
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Term
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Definition
| integral transform equation involving sinusoids. in the context of viscoelastic materials, fourier transforms relate the time and frequency domains |
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Term
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Definition
| energy approach to the fracture of a (brittle) material in which the fracture strength in tension is inversely proportional to the square root of theh crack length. the intrinsic properties of sureface energy and Young's modulus are directly related to the strength |
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Term
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Definition
| unit step function; has a value of zero for arguments less than zero, and one for arguments greater than zero. it is used in analysis of viscoelastic materials |
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Term
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Definition
| stress is linearly propoertional to strain. most materials follow this law at low strains |
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Term
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Definition
| properties of material are the same in every direction. materials such as steel and glassy polymers are usually isotropic, but composite materials and biological materials are not |
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Term
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Definition
| relationships between teh compliance of frequency in viscoelastic materials |
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Term
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Definition
| results when only a maximum amount of solute material can be dissolved in a solution (solid) |
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Term
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Definition
| iron carbon alloy (steel) obtained by quenching from austenite (y); has a body-centered tetragonal crystal structure. other silular crystal structures such as those occuring in shape memory alloys (e.g., nickel-titanium) are also called martensite |
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Term
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Definition
| mechanical analog model consisting of a spring and a dashpot in series for describing viscoelastic material properties |
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Term
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Definition
| unstable irreversible flow of material locally during tensile deformation, resulting in a neck-like shape |
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Term
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Definition
| having the same (atomic or micro) structure and properties throughout |
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Term
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Definition
| stress relaxation of viscoelastic materials is teh decrease in stress that occurs under constant strain. the relaxation modulus is the ratio of stress and strain during stress relaxation |
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Term
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Definition
| solid phase that contains more than two elements that are mixed uniformly everywhere in the phase |
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Term
| surface tension (surface energy) |
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Definition
| amount of free energy exhibited at the surface of a material |
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Term
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Definition
| toughening of martensite by heat treatment; the structure becomes more stable by converting to ferrite (a) and carbide microstructure |
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Term
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Definition
| amount of heat (thermal energy) passed for a given thickness, time, and cross-sectional area of a material |
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Term
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Definition
| amount of heat (thermal energy) passed for a given thickness, time, and cross-sectional area of a material |
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Term
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Definition
| amount of energy expended before its fracture or failure |
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Term
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Definition
| stress calculated based on a specimen's true cross-sectional area |
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Term
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Definition
| mechanical analog model describing materal properties by arranging a spring and a dashpot in parallel |
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Term
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Definition
| point of the stress-strain curve where transition takes place from elastic to plastic deformation, i.e., the curve deviates from initial linear portion |
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Term
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Definition
| absorption of sound or ultrasound waves |
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Term
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Definition
| mechanism for scattering of x-rays by free or weakly bound electrons in matter |
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Term
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Definition
| optical power of lens, or degree of ray divergence of a bundle of light rays. the power in diopters is the inverse of the focal length measured in meters |
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Term
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Definition
| electrical polarization of a material in response to mechanical stress |
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Term
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Definition
| ability of a material to pass a gaseous or ionic species, under a pressure gradient or a concentration gradient |
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Term
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Definition
| mechanism for the extinction of x-rays by the x-ray photon knocking bound electrons out of atoms |
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Term
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Definition
| electrical polarization of a material in response to temperature change |
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Term
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Definition
| electric potential developed when charged particles such as ions flow through a tube or porous medium such as bone; potential may be attributed to the imbalance created by washing away the eletric double layer |
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Term
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Definition
| set of four field equations that govern electricity, magnetism, radio wave propagation, and the behavior of light |
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Term
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Definition
| ratio of the speed of light in a vacuum to the speed of light in a material. it is a measure of the ability of a material to refract [bend] a beam of light |
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Term
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Definition
| governing equation for the angle of incident of refracted light rays |
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Term
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Definition
| a mathematical expression with well-defined transformation properties under changes in coordinates. a vector is a tensor of rank one; a scalar is a tensor of rank zero. stress and strain are examples of tensors of rank two |
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Term
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Definition
| alloy obtained by mixing silver tin alloy with mercury |
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Term
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Definition
| positive electrode in an electrochemical cell |
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Term
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Definition
| negative electrode in an electrochemical cell |
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Term
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Definition
| unwanted reaction of metal with environment. in a pourbaix diagram it is the region in which the metal ions are present at a concentration of more the 10^-6 molar |
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Term
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Definition
| form of localized corrosion in which concentration gradients around pre-existing crevices in the material drive corrosion processes |
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Term
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Definition
| temperature above which a ferromagnetic material ceases to be ferromagnetic. for a ferroelectric material used in piezoelectric transducers, the Curie point is the temperature at which teh material loses it permanent electric polarization. Control of the temperature of a magnetic metal implant is possible using electromagnetic induction and knowledge of teh Curie temperature. |
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Term
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Definition
| dissolution of metal driven by macroscopic differences in electrochemical potential, usually as a result of dissimular metals in proximity |
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Term
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Definition
| table of electrochemical potentials associated with ionization of metal atoms. these are called Nernst potentials |
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Term
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Definition
| temperature (>42 degrees C) above normal body temperature (37 degrees C). sufficiently high temperature can denature proteins, kill cells, and cause burns. prolonged heat may also produce heat shock proteins (hsp), which may resist heat better than normal protiens. |
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Term
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Definition
| resistance to corrosion by an energetic barrier. in a Pourbaix diagram it is the region in which the metal is in equilibrium with its ions at a concentration of less than 10^-6 molar |
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Term
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Definition
| standard electrochemical potential measured with respect to a standard hydrogen electrode |
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Term
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Definition
| type of metal with a positive standard electrochemical potential. noble metals resist corrosion by immunity. |
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Term
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Definition
| production of corrosion resistance resistance by a surface layer of reaction products |
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Term
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Definition
| resistance to corrosion by a surface layer of reaction products. in a Pourbaix diagram it is the region in which the metal is in equilibrium with its reaction products at a concentration of less than 10^-6 molar |
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Term
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Definition
| form of localized corrosion in wich pits form on the metal surface |
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Term
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Definition
| plot of electrical potential versus pH for a material in which the regions of corrosion , passivity, and immunity are identified |
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Term
| Shape memory effect (SME) |
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Definition
| Thermoelastic behavior of some alloys that can revert to their original shape when the temperature is greater than the phase transformation temperature of the alloy |
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Term
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Definition
| og phrase transformation: thermal energy required to overcome an energy barrier. E^activation=RT In(transformation rate), where R is the gas constant and T is temperature (K) |
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Term
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Definition
| aluminum oxide (A1^2O^3), which is very hard (Mohs hardress of 9) and strong. single crystals are called sapphire or ruby depending on the color. alumina is used to fabricate hip joint socket components or dental root implants |
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Term
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Definition
| mineral containing zircon |
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Term
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Definition
| trade name of alumina ceramic |
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Term
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Definition
| a family of calcium phosphate ceramics including hydroxyapatite B-whitlockite, mono-, di-, tri-, and tetra-calcium phosphate, which are used to make substitute or augment artificial bone substitutes |
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Term
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Definition
| partially stabilized zirconia in cubic structure to prevent fracture during cooling |
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Term
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Definition
| potential of an atom to attract electrons, especially in the context of forming a chemical bond |
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Term
| fluorite (CaF^2) structure |
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Definition
| AX^2 structure of ceramic, where A is a metal and X is a nonmetal |
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Term
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Definition
| a glass crystallized by heat treatment. some of those have the ability of forming chemical bonds with hard and soft tissues. Bioglass and Ceravital are well-known examples |
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Term
| hydroxyapatite [Ca^10(PO4)^6(OH)^2] |
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Definition
| a calcium phosphate ceramic with a calcium-to-phosphorus ratio of 5/3 and nominal composition. it has good mechanical properties and excellent biocompatibility. hydroxyapatite is the mineral constituent of bone |
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Term
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Definition
| a silicon alloyed pyrolytic carbon deposited onto a substrate at low temperature with isotropic crystal morphology. highly blood compatible and used for cardiovascular implant fabrication, such as artificial heart valves |
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Term
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Definition
| the ratio of atomic radii computed by assuming the largest aotm or ion which can be placed in a crystal's unit cell structure without deforming the structure |
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Term
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Definition
| a hardness scale in which 10 (diamond) is the highest and 1 (talc) is teh softest |
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Term
| partially stabilized zirconia |
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Definition
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Term
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Definition
| one crystal system having a=/=b=/=c, a=B=y=90 degrees |
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Term
| phase transformation toughening process |
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Definition
| by transforming phases under stress the material becomes stronger due to the volume expansion of the transformed phase |
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Term
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Definition
| one crystal system having a=b=/=c, a=B=y=90 degrees |
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Term
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Definition
| similar to the wear constant; wear volume generated by given load and sliding distance |
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Term
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Definition
| slope of teh Weibull plot. larger values indicate predictable failure stress. ceramics are 10~20, metals are >50 |
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Term
|
Definition
| plot of teh logarithm of probability of failure (F) [actually, 1n 1n 1/(1-F)] and test stress/strength fraction |
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Term
| B-whitlockite (3CaO`P^2O^3) |
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Definition
| one of the calcium phosphate compounds, similar to tricalcium phosphate, 3Ca`PO^4 |
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Term
|
Definition
| oxide used to partcially stabilize zirconia |
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Term
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Definition
| crystalline mineral, a silicate of zirconium with tetragonal structure |
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Term
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Definition
| Zirconium oxide, which is hard and strong |
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Term
| addition (or free radical) polymerization |
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Definition
| polymerization in which monomers are added to the growing chains, initiated by free radical agents |
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Term
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Definition
| the main molecular chain of a polymer |
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Term
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Definition
| inert ceramic mixed in the bone cement as powder to make it radio opaque to x-rays for better visualization of the implant on x-ray film |
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Term
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Definition
| mixture of polymethylmethacrylate powder and methylmethacrylate monomer liquid to be used as a grouting material for the fixation of othopedic implants |
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Term
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Definition
| chains grown from the sides of the main backbone chains |
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Term
| condensation (step reaction) polymerization |
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Definition
| polymerization in which two or more chemicals are reacted to form a polymer by condensing out small molecules such as water and alcohol |
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Term
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Definition
| polyacetal made by Union Carbide |
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Term
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Definition
| materials added as a powder to a rubber to improve its mechanical properties |
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Term
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Definition
| polymer that can absorb water 30% or more of its weight |
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Term
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Definition
| chemical inhibitor added to the bone cement liquid monomer to prevent accidental polymerization during storage |
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Term
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Definition
| chemical used to initiate the addition polymerization by becoming a free radical which in turn reacts with a monomer |
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Term
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Definition
| aromatic polyamides trademarked by DuPont |
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Term
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Definition
| polycarbonate trademarked by General Electric |
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Term
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Definition
| chemical added to the powder portion of the bone cement for the acceleration of its polymerization |
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Term
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Definition
| basic molecular unit that can represent a polymer backbone chain. the average number of repeating unit is called the degree of polymerization |
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Term
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Definition
| a time constant for stress relaxation assuming the polymer exhibits an exponential behavior. real polymers exhibit a distribution of relaxation times. this term is sometimes taken to refer to a time constant for other time-dependent processes. |
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Term
|
Definition
| a time constant for creep assuming the polymer exhibits an exponential creep behavior. real polymers exhibit a distribution of retardation times |
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Term
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Definition
| chemical group aattached to the main backbone chain. it is usually shorter than the branches and exists before polymerization |
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Term
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Definition
| acrylic bone cement made by Howmedica Inc. |
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Term
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Definition
| arrangement of side groups of a linear polymer chain that can be atactic (random), isotactis (same side), and syndiotactic (alternating side) |
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Term
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Definition
| polytetrafluoroethylene made by DuPont |
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Term
|
Definition
| polysulfone made by General Electric |
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Term
|
Definition
| crosslinking of a (natural) rubber by adding sulfer |
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Term
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Definition
| organometallic compounds which have the remarkable capacity of polymerizing a wide variety of monomers to linear and stereoregular polymers |
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Term
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Definition
| dependent upon direction, referring to the material properites of composites |
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Term
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Definition
| a type of cellular solid in which a cell wall isolates the adjacent pores |
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Term
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Definition
| composite materials are those that contain two or more distinct constituent materials or phases, on a microscopic or macroscopic size scale |
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Term
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Definition
| a type of anisotropic symmetry in which the unit cells are cube shaped. there are three independent elastic constants |
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Term
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Definition
| a type of anisotropic symmetry in which the unit cells are hexagonally shaped. there are five independent elastic constants. transverse isotropy is mechanically equivalent to hexagonal although the structure may be random in the transverse direction |
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Term
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Definition
| embedded phase of a composite |
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Term
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Definition
| independent of direction, referring to material properties |
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Term
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Definition
| the portion of a composite in which inclusions are embedded. the matrix is usually less stiff than the inclusions |
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Term
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Definition
| new lining of a blood vessel. it is stimulated to form by fabric-type blood vessel replacements |
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Term
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Definition
| a type of cellular solid in which there is no barrier between adjacent pores |
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Term
|
Definition
| a type of anisotropic symmetry in which the unit cells are shaped like rectangular parallelepipeds. in crystallography, this is called orthohombic. there are nine independent elastic constants. |
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Term
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Definition
| growth of tissue into the pores of an implanted porous biomaterial. such ingrowth may or may not be desirable |
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Term
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Definition
| cellular solid made using a biological material as a mold |
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Term
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Definition
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Term
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Definition
| a type of anisotrophic symmetry in which the unit cells are oblique parallelepipeds with unequal sides and angles. there are 21 independent elastic constants |
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Term
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Definition
| one of the essential amino acids |
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Term
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Definition
| small channels (~0.3 um in diamter) radiating from the lacunae in bone tissue |
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Term
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Definition
| calcifed tissue of mesodermal origin covering the root of a tooth |
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Term
|
Definition
| one of the polysaccharides commonly found in the cornea of the eye |
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Term
|
Definition
| sulfated mucopolysaccharides commonly found in cartilages, bones, cornea, tendon, lung, and skin |
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Term
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Definition
| a crown-shaped structure, especially the exposed or enamel covered portion of a tooth. it is largely (97%) made of hydroxypatite mineral. an artificial replacement of the exposed surface of the upper part of a tooth is also called a crown |
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Term
|
Definition
| the chief substance of the tooth, forming the body, neck, and roots, being covered by enamel on the exposed part of the tooth and by cementum on the root. is is simular in composition and properties (but not structure) to compact bone |
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Term
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Definition
| one of the crosslinking chemicals in elastin |
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Term
|
Definition
| one of the proteins in connective tissue. it is highly stable at high temperatures and in chemicals. it also has rubber-like properties; hence it is nicknamed "tissue rubber" |
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Term
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Definition
| one of the essential amino acids, much more commonly occurring in collagen than in elastin |
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Term
|
Definition
| one of the amino acids having the simplest structure |
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Term
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Definition
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Term
|
Definition
|
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Term
|
Definition
| one of the polysaccharides commonly found in synovial fluid, aortic walls, etc |
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Term
|
Definition
| mineral component of bone and teeth. it is a type of calcium phosphate, with composition Ca^10(PO^4)^6(OH)^2 |
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Term
|
Definition
| one of the amino acids commonly occuring in collagen molecules |
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Term
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Definition
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Term
|
Definition
| a pore (~10x15x25 um) in Haversian bone; lacune often contain osteocytes (bone cells) |
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Term
|
Definition
| one of the amino acids from which hydrogen bonding takes place stabilizing collagen chains |
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Term
|
Definition
| one of the crosslinking chemicals in elastin |
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Term
|
Definition
| properties of a material made of many materials depend linearly on the amount of each material contributed |
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Term
|
Definition
| large fiber-like structure (150~250 um in diamter) in compact bone. concentric layers or lamellae surround a central channelor Haversian cnal that contains a small blood vessel. each lamella contains smaller fibers. osteons, also called Haversian systems, are separated by cement lines |
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Term
|
Definition
| electric polarization resulting from mechanical stress upon a material; conversely, deformation resulting from an imposed electric field |
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Term
|
Definition
| polymerized sugar molecules found in tissues as lubricant (synovial fluid), cement (between osteons, tooth root attachment), or complexed with proteins, such as glycoproteins or mucopolysaccharides |
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Term
|
Definition
| richly vascularized and innervated connective tissue inside a tooth |
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Term
|
Definition
| one of the amino acids commonly occurring in collagen molecules |
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Term
|
Definition
| electric potential generated in the (solid) wall of a channel when charged particles are flowing and polarized takes place in the wall |
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Term
|
Definition
| precursor of collagen, right-handed superhelical coil structure, which, in turn, is made of three left-handed helical peptide chains |
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Term
|
Definition
| one of the essential amino acids more commonly occurring in elastin than in collagen |
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Term
|
Definition
| vascular channels in compact bone. they are not surrounded by concentric lamellae as are the Haversian canals |
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Term
|
Definition
| remodeling of bone takes place in response to mechanical stimulation, so that the new structure becomes better adapted to the load |
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Term
|
Definition
| released through the vessel walls after injury, in turn releasing coagulation agents |
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|
Term
| adenosine diphosphate (ADP) |
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Definition
| a ompound consisting of an adenosine molecule bonded to three phosphate groups, present in all living tissue. the breakage of one phossphate linkage (to form adenosine diphosphate, ADP) provides energy for physiological processes such as muscular contraction |
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Term
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Definition
| a naturally occurring carcinogenic material. it is formed by mold infestation of food crops such as corn or peanuts |
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Term
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Definition
| a screening test for carcinogenic potential of a material. genetic mutations are observed in bacteria; carcinogenicity is correlated with mutagenicity |
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Term
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Definition
| acceptance of an artificial implant by surrounding tissues and by the body as a whole. the implant should be compatible with tissues in terms of mechanical, chemical, surface, and pharmacological properties |
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Term
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Definition
| unorganized fibrous collagenous tissue formed during the healing process of bone fracture. it is usually replaced with compact bone |
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Term
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Definition
| any substance that produces cancer |
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Term
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Definition
| any foreign matter, as a blood clot or air bubble, carried in the bloodstream |
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Term
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Definition
| the study of disease incidence in a population of humans. epidemiologic study constitutes the final test of the potential of a causative agent, such as a biomaterial, in inducing disease |
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Term
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Definition
| this refers to the solid components of blood-red and white blood cells and platelets |
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Term
| Hageman Factor (Hfa, Factor XII) |
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Definition
| the first of the cascading events of blood vessel wall damage control |
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Term
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Definition
| a substance found in various body tissues, especially in the liver, that prevents the clotting of blood |
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Term
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Definition
| highly hydrated (over 30% of weight) polymer gel that is used to make soft contact lenses. acrylamide and poly-HEMA (hydroxyethylmethacrylate) are two common hydrogels |
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Term
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Definition
| the consequences of blood vessel wall damage described in a cascading manner from triggeringHfa to the dilation of blood vessels and increased vascular permeability |
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Term
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Definition
| this is the assumption that the incidence of cancer produced by a carcinogen is linearly proportional to the dose |
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Term
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Definition
| any of various phagocytic cells in connective tissue, lymphatic tissue, bone marrow, etc. sometimes called foreign body giant cell, and is associated with the presence of implants. becomes multinucleated if teh implant is not biocompatible |
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Term
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Definition
| sometimes called pseudointima. it is a new lining formed in the inner surface of porous arterial grafts, and it has simular nonthrombogenic properties as the intima (natural lining) of the arteries |
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Term
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Definition
| polychlorinated biphenyl, an industrial carcinogen. it is not used in biomaterials |
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Term
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Definition
| a small colorless disk-shaped cell fragment without a nucleus, found in large numbers in blood and involved in clotting. also called a thrombocyte |
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Term
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Definition
| a temporary protrusion of the surface of an ameboid cell for movement and feeding |
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Term
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Definition
| silicon dioxide, SiO^2. it is chemically identical to the mineral quartz and is used in particle form as a filler in polymeric and rubbery materials |
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Term
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Definition
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Term
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Definition
| polydimethyl siloxane, a polymer that contains the element silicon. it is available in rubber and gel forms. it is used in soft tissue reconstruction in the face, as well as in breat implants |
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Term
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Definition
| this is the assumption of a nonlinear relation between the dose of a carcinogen and the number of cancers produced. more commonly a linear relation is assumed. see linearity hypothesis |
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Term
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Definition
| an enzyme in blood plasma that causes the clotting of blood by converting fibrinogen to fibrin |
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Term
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Definition
| the fibrinous clot attached at the site of thrombosis |
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Term
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Definition
| a material used for the strings of musical instruments and for surgical absorbable sutures. it is made of the dried twisted intestines of sheep or horses, but not cats |
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Term
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Definition
| chemical compound that is used to treat collagen to achieve crosslinking between molecular chains of collagen. such treatment increases its strength but decreases its flexibility |
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Term
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Definition
| the spiral cavity of the inner ear containing the organ of Corti, which produces nerve impulses in response to sound vibrations |
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Term
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Definition
| a polymer used as a tissue adhesive since it can polymerize fast in the presence of water |
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Term
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Definition
| Polyethylene terephthalate polyester that is made into fibers. if the same polymer is made into a film, it is called Mylar |
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Term
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Definition
| Food and Drug Administration, which regulates the use of medical devices in the United States |
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Term
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Definition
| an insoluble protein formed from fibrinogen during the clotting of blood. it forms a fibrous mesh that impedes the flow of blood |
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Term
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Definition
| a plasma protein of high molecular weight that is converted to fibrin through the action of thrombin. this material is used to make (absorbable) tissue adhesives |
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Term
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Definition
| a condition in which fluid accumulates in the brain, typically in young children, enlarging the head and sometimes causing brain damage |
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Term
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Definition
| a gel in which the liquid component is water (>30% by weight) |
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Term
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Definition
| surgery carried out on the cornea, especially corneal transplantation |
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Term
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Definition
| similar to lasik and uses an active radar eye tracking system, which compensates for involuntary eye movements |
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Term
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Definition
| (laser in-situ keratomileusis): surgical correction of teh curvature of the cornea using a laser |
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Term
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Definition
| (laser in-situ keratomileusis): surgical correction of teh curvature of the cornea using a laser |
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Term
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Definition
| (ossicular, adj.): a small bone, especially one of those in the middle ear |
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Term
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Definition
| an implant designed to transfer matter, information, etc. from the body to the outside of the body transcutaneously |
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Term
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Definition
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Term
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Definition
| polymer made from glycolic acid and used to make absorable sutures or other products |
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Term
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Definition
| polymer made from lactic acid and used to make absorbable sutures or other products |
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Term
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Definition
| a composite material made of fibrous polytetrafluoroethylene and carbon. it is usually porous and has a low modules and low strength |
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Term
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Definition
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Term
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Definition
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Term
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Definition
| the central duct of the cochlea in the inner ear, containing the sensory cells and separated from the scala tympani and scala vestibuli by membranes |
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Term
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Definition
| a polymer containing the element silicon. depending on molecular weight, it may be a gel or a rubber |
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Term
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Definition
| material used in closing a wound with stiches |
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Term
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Definition
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Term
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Definition
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Term
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Definition
| a commercial method using an excimer laser to treat myopia |
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Term
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Definition
| interconnection between two blood vessels |
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Term
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Definition
| abnormal dilation or bulging of a segment of a blood vessel, often involving the aorta or pulmonary artery |
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Term
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Definition
| surgical repair or unblocking of a blood vessel, especially a coronary artery |
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Term
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Definition
| use of synthetic polymers [perfloroctyl bromide (C^8F^17Br) or perfluorodichloroctane (C^8F^16C1^2)] or regenerated blood cells to substitute blood |
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Term
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Definition
| a transplanted tissue or organ transferred from one part of a body to another part of the same body |
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Term
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Definition
| a thin tube inserted into a vein or body cavity to administer medicine, drain off fluid, or insert a surgical instrument |
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Term
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Definition
| a unit of weight for measuring the fineness of threads of silk, rayon, nylon, etc., equal to 1 gram per 9000 meters |
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Term
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Definition
the part of a mixture that passes through the membrane in dialysis.
~the solution this forms with the fluid on the other side of the membrane
~the fluid used on the other side of the membrane during dialysis to remove impurities |
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Term
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Definition
| the separation of particles in a liquid on the basis of differences in their ability to pass through a membrane |
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Term
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Definition
| a cell in connective tissue that produces collagen and other fibers |
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Term
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Definition
| a small tuft or cluster, as ofblood vessels or nerve fibers; applied especially to the coils of blood vessels, one projecting into the expanded end or capsule of each of the uriniferous tubules of the kidney |
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Term
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Definition
| incomplete closure of a heart valve |
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Term
| left-ventricular assist device (LVAD) |
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Definition
| balloon-type heart assist device connected to left ventricle of the heat |
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Term
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Definition
| new lining, intima (blood vessel lining) formed by ingrowth of tissues through pores of a vascular graft |
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Term
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Definition
| an apparatus by which oxygen is introduced into the blood during circulation outside the body, as during open-heart surgery |
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Term
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Definition
| a device designed to stimulate, by electrical impulses, contraction of the heart muscle at a certain rate |
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Term
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Definition
| the membrane enclosing the heart, consisting of an outer fibrous layer and an inner double layer of serous membrane |
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Term
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Definition
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Term
| pyrolysis (pyrolytic, adj.) |
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Definition
| decomposition brought about by high temperatures |
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Term
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Definition
| backflow of blood of a heart valve |
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Term
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Definition
| devices or materials made by replicating natural tissues such as sea urchin tentacles. the objective is to achieve better tissue ingrowth into the pores |
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Term
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Definition
| a substance that has the property of collecting molecules of another substance by sorption |
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Term
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Definition
| the ability of some substances to soak up or attract materials such as contaminants and hold them |
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Term
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Definition
| a tubular support placed temporarily inside a blood vessel, canal, or duct to aid healing or relieve an obstruction |
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Term
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Definition
| the normalized strength of a fiber; strength per unit size (e.g., expressed in terms of denier). tensile strength=tenacityxdensityxconstant, in appropraite units |
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Term
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Definition
| a transplanted tissue or organ transferred from an individual of another species |
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Term
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Definition
| bone morphogenic protein. see morphogen. this is a protein used to stimulate bone growth |
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Term
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Definition
| interactions amoung pluripotential cells and bone morphogenetic proteins (BMPs), converting these cells to osteoblasts |
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Term
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Definition
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Term
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Definition
| dense compact bone found in the cortex (outer layer) of a bone |
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Term
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Definition
| bone plate designed to give compression on the fractured site of a broken bone for fast healing. a minimum amount of callus is observed; this is considered to be a better sign of healing in comparison with the conventional plate. |
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Term
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Definition
| tissues can be stimulated by applying a small amount of electrical energy in either alternating or direct current at low electrical potential so as not to hydrolyze the water medium. dosage-response relationships are not fully established yet for various tissues |
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Term
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Definition
| one of the stainless steels made of 18w/o Cr, 8 w/o Ni and a small (2-4 w/o) amount of Mo for saltwater corrosion resistance |
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Term
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Definition
| plate used to fix broken bones by open (surgical) reduction. screws are used to fix it to the bone |
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Term
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Definition
| a wire-wound coil to generate (pulsed) electromagnetic field to induce electric current in the tissues to stimulate their growth |
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Term
| Hoffmann external fixator |
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Definition
| a mechanical device used to reattach broken long bones using percutaneously inserted pins to compress the bones together for faster healing |
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Term
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Definition
| a rod-like device inserted into the intramedullary marrow cavity to promote healing of long bone (spiral, non-comminutive) fractures |
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Term
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Definition
| metal surgical wires with diameters less than 3/32 inches (2.38 mm) |
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Term
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Definition
| first fracture plate used extensively for repair of broken long bones designed by Dr. Lane in teh first years of the twentieth century |
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Term
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Definition
| abnormally increased concavity in the curvature of the lumbar spine |
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Term
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Definition
| cartilage-derived morphogenetic proteins-1 and -2 (CDMP-1 and -2) to regenerate form for skeletal insufficiencies caused by oncologic resection, trauma, disease, or developmental deficiency |
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Term
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Definition
| condition of insufficient bone mass or density |
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Term
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Definition
| condition of abnormally high porosity of bone. Osteoporosis is associated with aging and with disuse atrophy due to inactivity. it can also be caused locally by shieling of stress by an implant or deficiency of calcium or vitamin D |
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Term
|
Definition
| one of the intramedullary rods used to fix broken long bones |
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Term
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Definition
| lateral curvature of vertebral column; it is always abnormal |
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Term
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Definition
| metal pins with diameters greater than 3/32 inches (2.38 mm) |
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Term
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Definition
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|
Term
| Strain-generated electric potential |
|
Definition
| electric potential generated due to strains during deformation of the bone. they may be related to the remodeling processes of bone |
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Term
|
Definition
| prolonged reduction of stress on a bone may result in porotic bone (osteoporosis), which may weaken it. the process can be reversed if the natural state of stress can be restored to its original state |
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Term
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Definition
| originally the name was given to 19-9 stainless steel, but it was changed to designate a Co-Cr alloy |
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Term
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Definition
| the socket portion of the hip joint |
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Term
|
Definition
| mineral phase of bone usually found as hydroxyapatite, Ca^10(PO^4)^6(OH)^2 |
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Term
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Definition
| plastic repair of a joint |
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Term
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Definition
| popular dental implant supposed to be integrated with bone of the root portion. it is made of Ti alloys such as Ti6A14V |
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Term
|
Definition
| polysiloxane modified styrene-ethylene/butylene-styrene block copolymer of thermoplastic elastomer |
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Term
|
Definition
| commercially pure Ti having excellent corrosion resistance and biocompatibility |
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Term
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Definition
| co-based alloys commonly used in orthopedic implants. some are made castable (CoCrMo) or hot-forgable (CoNiCrMo). these alloys are stiff and strong and offer good corrosion resistance |
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Term
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Definition
| polyethylene terephlhalate polyester that is made into a fibrous form |
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Term
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Definition
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Term
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Definition
| in the bone, referring to dental implants fixed to the jawbone |
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Term
| finite-element analysis or model (FEA or FEM) |
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Definition
| study of a structure or structural member by subdividing it into small elements (mesh). a computer is used to analyze stresses and strains. the stresses/strains are then expressed in a graphic form |
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Term
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Definition
| a ceramic made by controlled nucleation and crystallization for fine grains with capacity for tissue bonding by selected surface dissolution. Bioglass is an example |
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Term
|
Definition
| high-density polythylene, having a high m.w. and crystallinity, resulting in high-density and moderate m.w. (1/2 million amu). before ultrahigh-m.w. polyethylene (UHMWPE) was avaliable. HDPE polymers were used extensively in the early 1980s |
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Term
|
Definition
| high-density polythylene, having a high m.w. and crystallinity, resulting in high-density and moderate m.w. (1/2 million amu). before ultrahigh-m.w. polyethylene (UHMWPE) was avaliable. HDPE polymers were used extensively in the early 1980s |
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Term
|
Definition
| high-density polythylene, having a high m.w. and crystallinity, resulting in high-density and moderate m.w. (1/2 million amu). before ultrahigh-m.w. polyethylene (UHMWPE) was avaliable. HDPE polymers were used extensively in the early 1980s |
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Term
|
Definition
| hexene-bsed polyolefin rubber |
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Term
|
Definition
| one of the polysccharides commonly found in synovial fluid, the aortic wall, etc. |
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Term
|
Definition
| highly hydrated (over 30% by weight) polymer gel used to make soft contact lenses, such as acrylamide and poly-HEMA (hyroxyethylmethacrylate) |
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Term
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Definition
| the sequence of reactions by which most living cells generate energy during the process of aerobic respiration. it takes place in the mitochondria, consuming oxygen, producing carbon dioxide and water as waste products, and converting ADP to energy-rich ATP |
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Term
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Definition
| type of woven polyethlene |
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Term
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Definition
| Ni-Ti shape memory alloy originally experimented with at the Naval Ordinance Labatory; hence the name |
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Term
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Definition
| direct apposition of bone on the implant surface without intervening collagenous membrane formation. it is largely used in dentisty, not in orthopedics. Branemark dental implant represents such a implant fixation technique in bone |
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Term
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Definition
| a biodegradable polymer made from glycolic acid |
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Term
|
Definition
|
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Term
|
Definition
| a biodegradable polymer made form lactic acid |
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|
Term
| polymethylmethacylate (PMMA) |
|
Definition
| an amorphous, hard plate used to make bone cement and hard contact lens |
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Term
|
Definition
| a composite material made of carbon and polytetrafluoroethylene. it has moderate porosity and strength |
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Term
|
Definition
| alloys having "recovery of its shape" by thermomechanical transformation of its crystalline structure (see Nitinol) |
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Term
|
Definition
| polydimethyl siloxane silicone elastomer |
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Term
|
Definition
| iron- (Fe) based alloys made to resist corrosion by adding Cr, Ni, and small amounts of Mo. by lowering C (.8 to .3%), the corrosion resistance of the stainless steel can be enhanced (316 to 316L) |
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Term
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Definition
| bone lying under the cartilage of a joint |
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Term
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Definition
| a gel that, when disturbed or shaken, will become fluid, and if left undisturbed will set into a gel; it is a reversible transformation that can occur under application of isothermal shearing stresses followed by rest. ketchup is a typical example |
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Term
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Definition
| one of the most widely used Ti alloys having a relatively low modules for a metal (110 GPa) with high strength and corrosion resistance. it has about half the specific gravity of Co-based alloys and stainless steels. 6 w/o aluminium and 4 w/o vanadium are alloyed for preserving phases (B for V, a for A1), density, and process consideration |
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Term
|
Definition
| a defunct dental root implant made of glassy carbon |
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Term
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Definition
| ultrahigh-molecular-weight polyethylene, having m.w. = 2~4 million amu, semicrystalline, thermoplastic, linear polymer used in the acetabular cup of hips and tibia plateaus of joint fabrication |
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Term
|
Definition
| SiO^2-CaO ceramic used to make glass-ceramics with apaitite |
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Term
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Definition
| transplant between different individuals of teh same species |
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Term
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Definition
| joining two blood vessels or other tubular structures in the body |
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Term
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Definition
| a forgeign protein that elicits an aimmune system response |
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Term
|
Definition
| transplant within one individual, from one part of teh body to another |
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Term
|
Definition
| compatibility of nonliving implant materials with the body |
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Term
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Definition
| death of the brain including the brain stem resulting in unreceptivity and unresponsivity, absence of spontaneous respiration or movement, absence of relexes, and a flat EEG |
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Term
|
Definition
| an immunosuppressive drug |
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Term
|
Definition
| electroencephalogram, wich is a plot of teh electrical activity of the brain as measured via electrodes on the scalp |
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Term
|
Definition
| compatibility of transplant tissue with teh recipient's body in relation to immune response |
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Term
|
Definition
| referring to the ilium, the large flat bone of teh pelvis |
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Term
|
Definition
| a cluster of endocrine cells found in the pancreas; they secrete insulin. |
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Term
|
Definition
| transplant between genetically identical individuals, i.e., identical twins |
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Term
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Definition
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Term
|
Definition
| transplant between different individuals of the same species |
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Term
|
Definition
| transplant between members of different species |
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Term
|
Definition
| transplanted in a location different from teh anatomically correct one |
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Term
|
Definition
| abnormally low body temperature. it can cause an unresponsive condition that can mimic brain death, so transplants are not taken from hypothermic patients |
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Term
|
Definition
| a type of cancer, once rare, now largely associated with immune system deficiencies such as those produced in AIDS or by immunosuppressive drugs used in transplant procedures. this disease produces bluish skin lesions |
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Term
|
Definition
| replacement of the cornea |
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Term
|
Definition
| transplanted in the anatomically correct location |
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Term
|
Definition
| a neurological disorder characterized by tremor and paralysis. attempts have been made to cure it by transplantation of brain or adrenal cells into the brain |
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Term
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Definition
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Term
|
Definition
| surgical reattachment of a severed body part |
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Term
|
Definition
| immunologically competent cells derived from the thymus |
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Term
|
Definition
| transfer of a tissue or organ from one body part to another, or from one location in a body to another |
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Term
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Definition
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Term
|
Definition
| any one group of organic chemical compounds having the radical CHO, derived from the primary alcohols by oxidation of methanol (CH^3CHO) |
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Term
|
Definition
| a transplant from a part of one's body to another part of the body |
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Term
|
Definition
| derived from a person's own tissue |
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Term
|
Definition
| being absorbed by blood or tissues of the decomposed polymer by products in vivo |
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Term
|
Definition
| being decomposed by bacterial or enzymatic action in vivo |
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Term
|
Definition
| erosin of polymers by breakage main chains or crosslinks |
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Term
|
Definition
| a horny substance forming the hard outer covering of lobsters, crabs, beetles, crickets, and some fungi; closely related to cellulose |
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Term
|
Definition
| a derivative of chitin by N-deacetylation |
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Term
|
Definition
| protein substance in the fibers of connective tissues, bone, and cartilage of vertebrates. boiling with water converts collagen to gelatin |
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|
Term
| collagen-glycosaminoglycan copolymer |
|
Definition
| two natural polymers made into a copolymer, one being protein (collagen) and another polysaccharide, would give good mechanical, chemical, and biologicalproperties for such applications as scaffold material |
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Term
|
Definition
| suture made of copolymer of PGA and PLA (Davis and Geck, Danbury, CT) |
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Term
|
Definition
| an insoluble protein formed from fibrinogen during the clotting of blood. it forms a fibrous mesh that impedes the flow of blood |
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Term
|
Definition
| denatured collagen obtained by boiling bones and cartilage |
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|
Term
| glutaraldehyde (C^5H^8O^2) |
|
Definition
| chemical made from cyclohexene in atmospheric reaction, used to preserve tissues and serilization |
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Term
|
Definition
| the property of causing immunity (antigenicity) to a disease |
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Term
|
Definition
| poly(hydroxybutylate), a natural polymer usually copolymerized with PHV to make biodegradable polymer scaffolds |
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|
Term
|
Definition
| poly(hydroxybutylate), a natural polymer usually copolymerized with PHV to make biodegradable scaffolds |
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|
Term
|
Definition
| poly(hydroxyvaleric acid), a natural polymer usually copolymerized with PHB to make biodegradable polymer scaffolds |
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Term
|
Definition
| erosin of polymers at the surface or bulk |
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Term
|
Definition
| poly(lactic acid), one of the synthetic polymers, poly(a-hydroxyesters) used to make biodegradable scaffolds |
|
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Term
|
Definition
| step-reaction polymerized polymer from HOOC(CH^2)^8COOH resulting in HO[-CO(CH^2)^XCOO-]^YH+H^2O |
|
|
Term
| poly(e-caprolactone) (PCL) |
|
Definition
| a biodegradable, biocompatible, thermoplastic homopolymer used to coat, fabricate scaffold, films, etc. can be copolymerized to modify its properties |
|
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Term
|
Definition
| a polymer produced from 3,9-bis(ethylidene 2,4,8,10-tetraoxaspirol [5,5]undecane) (DETOSU) condensed with di-alcohols. this generation of POEs released nonacidic byproducts and eliminated teh autocatalytic process. combined with certain additives, POes were found to degrade by surface erosion, making DETOSU-based POEs well suited for controlled drug delivery |
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Term
|
Definition
| consisting of an optically inactive, equimolar mixture of the dextrorotatory and levorotatory forms of certain substances |
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|
Term
|
Definition
| a material, typically a polymer, being absorbed by the body in vivo |
|
|
Term
| sodium alginate (C^6H^7NaO^6)^n |
|
Definition
| sodium salt of alginic acid, with 10~600 k m.w. dissolves slowly in water, forming a viscous solution; used as stabilizer, thickener, gelling agent, and emulsifier |
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Term
|
Definition
| undifferentiated cells capable of proliferation and of self-renewal and of differentiation into at least one type of specialized cells |
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|
Term
|
Definition
| an intersdisciplinary field involving engineering and life sciences for the development of biological substitutes containing living cells, with the aim to restore, maintain, or improve cells, tissues, and organs in the body |
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Term
|
Definition
| suture made of copolymer of PGA and PLA (Ethicon, Somerville, NJ) |
|
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Term
|
Definition
| a metallic material that is obtained by chemical combinations of different elements, typicall alloys ahve much better mechanical properties than pure metals |
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Term
|
Definition
| a group of crystalline inorganic materials characterized by good strength, especially in compression and high melting temperatures, many have good electrical and thermal insulation behavior |
|
|
Term
|
Definition
| a group of material formed from mixtures of metals, ceramics, or polymers in such a manner that unusual combinations of properties are obtained. |
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Term
|
Definition
| the chemical makeup of a material |
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Definition
| the arrangment of atoms in a crystalline material |
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| a material comprised of one or many crystals, in each crystal atoms or ions show a long range periodic arrangement |
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| an amorphous material derived from teh molten state, typically, but not always bsed on silica |
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| a special class of materials obtained by forming a glass and then heat treating it to form small crystals. |
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| regions between grains of a polycrystalline material |
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| crystals in a polycrystalline material |
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| properties of a material, such as struegth, that describe how well a material withstands applied forces, a materials response to an applied force, microstructure sensitve |
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| describe characteristics such as color, elasticity, electrical or thermal conductivity, magnetism, etc. a material's response to an applied fied, not microstructure sensitive |
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| a material comprised of many crystals (as opposed to a material comprised of just one crystal) |
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| a group of materials normally obtained by joining organic molecules into gian molecular chains or networks, characterized by low strength, low melting temperatures and poor electrical conductivity. |
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| a special group of polymers in which molecular chains are entangled, but not interconnected, they can easily be melted and formed into useful shapes, normally they have a chinline structure (eg polyethylene) |
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| a spcial group of polymers that decompose ratehr than melt upon heating, they are normally quite brittle due to a relatively rigid 3-D network structure (eg-polyurethane) |
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| polymers that have a higly coiled structure that provides them with the ability to exhibit extreme elastic deformation. |
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| a material that does not have a long range order of atoms (only short range order) |
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| a negatively charged ion produced when an atom, usually of a nonmetal, accepts one or more electrons. |
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| all atoms and their arrangments that constitute teh building blocks of matter |
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| The energy required to separate two atoms from their equilibrium spacing to an infinite distance apart, the strength of the bond between two atoms. |
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| a positively charged ion produced when an atom usually a metal gives up its valence electrons |
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Term
| coefficient of thermal expansion (CTE) |
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Definition
| The amount by which a material changes its dimesnions when teh temperature dhanges, a material with a low cte tends to retain its dimesnions when the temperature is changed. |
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Definition
| the bond formed between tewo atoms wehn the atoms share their valence electrons, a relatively strong primary bond. |
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Definition
| materials in which atoms are arranged in a periodic fashion exhibiting a long-range order |
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| the ability of materials to be stretched or bent without breaking |
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Definition
| the trelative tendancy of an atom to accept an electron and become an anion, strongly electronegative atoms readily accept electrons |
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Definition
| the equilibrium spacing between teh centers of two atoms. |
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Definition
| the bond formed between two different atom species when one atom (the cation) donates its valence electrons to teh second atom (the anion), an electrostatic attraction binds the two ions together (relatively strong primary bond) |
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Definition
| structures of a material at the macroscopic level (~>1000-10,000 nm), features include things such as porosity, coatings, internal and external microcracks, etc |
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| the electrostatic attraction between teh valence electrons and the positively charged ionic cores |
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| structure of amaterial at a length scale of ~10 - 1000 nm, includes features such as grain size, grain orientation, defects, etc |
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Definition
| the slope of the stress strain curve in the elastic region(E), also known as Young's modulus |
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Definition
| molecules that have developed a dipole moment by virtue of an internal or external electric field |
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Definition
| strong bonds between adjacent atoms resulting form the transfer or sharing of outer orbital electrons |
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Definition
| the number of electrons in an atom that participate in bonding or chemical reactions, usually teh number of electrons in teh outer s and p energy levels |
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Definition
| secondary bond developed between atoms and molecules as a result of interactions between dipoles that are induced or permanent |
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| the characterisitic of an element being able to exist in more than one crystal structure depending on temperature and pressure |
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Definition
| materials including glass that have no long-range order, or crystal structure |
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Definition
| having different properties in different directions |
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| fourteen possible lattices that can be created using lattice points (show location of atoms) |
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Definition
| directions in a crystal along which atoms are in contact |
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Definition
| the number of nearest neighbors to an atom in its atomic arrangement 9speaks to how efficiently packed a unit cell is) |
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Definition
| the arrangement of atoms in a material into a regular repeatable lattic |
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Definition
| the generic size and shape of a unit cell, include cubic, tetragonal, orthrombic, hexagonal, monoclinic, rhombohedral and triclinic |
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Definition
| materials that have long range order (composed of many small grains or crystals) |
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| a microstructural reature representing a disruption in teh periodic arrangment of atoms/ions in a crystalline material. |
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| crystallographic directions that all have teh same cahracteristics although their sense is different, generic directions, denoted by < > |
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| a family of materials typically derived from molten inorganic glasses and processed into crystalline materials with very fine grain size and improved mechanical proeprties |
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Definition
| solid, non-crystalline materials that have only short range atomic order (amorphous) |
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Definition
| small crystal in a polycrystalline material |
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Definition
| regions between grains of a polycrystalline material |
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Definition
| locations between teh normal atoms or ions in a crystal into which anothre usually different atom or ion is placed, typically teh sie of the interstitial location is smaller than the atom or ion that is to be introduced |
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| having the same properties in all directions |
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| a collection of points that divide space into smaller equally sized segments |
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Definition
| the lengths of sides of teh unit cell and teh angles between those sides, describe the size and shape of the unit cell |
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Definition
| the number of lattice points per unit length along a direction |
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| shorthand notation to describe crystallographic planes and directions |
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| the fraction of a direction or plane that is actually covered by atoms or ions, speaks to how efficiently packed a unit cell is in a direction or on a plane |
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Definition
| the number of atoms per unit area whose centers lie on the plane |
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Definition
| crystallographic planes taht all have the same cahracteristics even though theri orientations are different; denoted by { } |
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Definition
| material composed of many grains |
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Definition
| compounds exhibiting more than one type of crystal structure 9similar to allotropic) |
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Definition
| the distance from one lattice point to the adjacent lattice point along a direction |
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Definition
| the regular and predictable arrangement of atoms over shrot distances usually one or two atom spacings only |
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Definition
| the sequence in which close-packed planes are stacked, if teh stacking sequence is ABABABAB a HCP structure is produced, if a stacking sequence of ABCABCABC then an FCC structure is produced |
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Definition
| a subdividion of teh lattice that still retains teh overall cahracteristics of the entire lattice |
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Definition
| the direction and distance that a dislocation moves in each step, aka slip vector |
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Term
| critical resolved shear stress |
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Definition
| the shear stress required to cause a dislocation to move and cause slip |
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Term
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Definition
| a change in the slip system of a dislocation |
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Definition
| a line imperfection in a crystalline material, movement of dislocations helps explain how a metallic material deforms, interference with the movement of these helpse explain how metallic materials are strengthened |
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Term
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Definition
| dislocation that is made up of an extra "half plane" of atoms, burgers vector is perpendicular to dislocation line |
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Definition
| deformation that is fully recovered when the stress causing it is removed, results from the bonds stretching |
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Term
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Definition
| a pair of pinte defects produced when an ion moves to create an interstitial site leaving behind a vacancy |
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Term
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Definition
| a surface defect representing the boudnary between two grains, the crystal has a different oriention on either side of the grain |
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Definition
| point defect produced when an atom is placed into teh crystal at a site that is not normally a lattice point |
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Definition
| defects such as dislocations in which atoms or ions are missing in a row (1-D) |
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Term
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Definition
| a dislocation that contains partly edge components and partly screw components |
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Definition
| The shear stress, which depends on the Burgers vector and teh interplanar spacing , required to cause a dislocation to move |
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Term
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Definition
| permanent deformation of a material |
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Term
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Definition
| imperfections such as vacancies that are located typically at one or a few sites in a crystal. |
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Definition
| The relationship between shear stress , teh applied stress, and teh orientation of the slip system |
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Term
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Definition
| A point defect iinionically bonded materials, a stoichiometric number of cation and anion vacancies |
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Term
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Definition
| a dislocation produced by skewining a crystal so that one atomic plane produces a spiral ramp about dislocations |
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Term
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Definition
| deformation of a metallic material by movement of dislocations through the crystal |
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Definition
| direction in the crystal in which the dislocation moves |
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Definition
| the plane swept out by the dislocation line during slip, normally the slip plane is a close packed plane if one exists in the crystal structure |
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Definition
| combination of a slip direction and slip plane |
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Term
| small angle grain boundary |
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Definition
| surface or planar defect made up of an array of dislocations cuasing a small misorientation of teh crystal across teh surface of the imperfection |
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Term
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Definition
| a surface defect in an fcc materal caused by the improper stacking sequence of close-packed planes |
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Term
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Definition
| a point defect produced wehn an atom is removed from a reular lattice point and replaced with a different atom usually having a different size |
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Definition
| imperfections such as grain boundaries that form a 2D plane within the crystal |
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Definition
| small angle graoun boundary composed of an array of edge dislocations |
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Term
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Definition
| a surface defect across which there is a mirror image misorientation of teh crystal structure |
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Definition
| small angel grain boudnary made up of an array of screw dislocations |
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Term
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Definition
| point defect where an atom is missing from its regular cyrstallographic site |
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