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Permeability coefficient of a small gas molecule in a biocompatible

05/08/2019

Schematically explain the fiber orientation and crack formation of the fiber reinforced biocomposites (less than one page).(10)Three distinct fracture modes are involved in crack formation includeMode 1: opening modeMode 2: sliding modeMode 3: tearing modeQuestion 2:What are the major concerns of the biocomposites when they are used as implants inside the human body (less than one page)?(10)The main problem caused by biocomposites when used as implants is that they lead to immunogenic responses that can occur due to incompatibility and the lot-to-lot variability of molecular structure associated with animal sourceQuestion 3:Schematically elucidate about the physical degradation mechanisms of bioerosion process of biodegradable polymers when they are placed in the body (less than one page).

(10)Schematic presentation of surface erosionGiven that the rate of covalent bonding cleavage is higher than the rate of influx of the degrading agents affecting the polymer, the material encounter surface is eroding. On the other hand, given that the rate of degrading agent influx is higher than the bonding cleavage rate, the material will undergo bulk eroding. The degradation process occurs simultaneously in the entire volume of the medical device.

Question 4: Mention about the hydrogels fabrication, and characterization processes, and their major biomedical applications (less than one page). (10)Hydrogels refer to crosslinked polymeric networks. They are characterized by the ability to hold water within their spaces of polymeric chains. Hydrogels have been applied in various biomedical applications, such as drug delivery, cell carriers, and entrapment, wound management as well as tissue engineeringQuestion 5: What are the major types of stents and pacemakers and what types of biomaterials are used to build those biodevices (less than one page)? (10)Most stents are generated from stainless steel platform and platform materials such as gold, titanium, tantalum alloy, nitinol, cobalt chromium, alloy, and several types of polymerTypes of pacemakers• Single chamber pacemakers• Dual chamber pacemakers• Biventricular pacemakerQuestion 6:For a continuous and oriented fiber-reinforced biocomposite, the moduli of elasticity in the longitudinal and transverse directions are 32.2 and 3.74GPa, respectively. If the volume fraction of fibers in the biocomposite is 0.35, determine the moduli of elasticity of fiber and matrix phases.

Permeability coefficient of a small gas molecule in a biocompatible polymer is dependent on absolute temperature according to the following equationwherePMo and Qpare constants for a given gas-polymer pair. Consider the diffusion of water through a polystyrene sheet 15 mm thick. The water vapor pressures at the two faces are 25kPa and 2.5kPa, which are maintained constant. Compute the diffusion flux values at 200 K and 400 K. The gas constant is 8.314 J/mol.K.For this diffusion system with PMo and Qp below, assume a condition of steady-state diffusion(10).= (1.0 * 58.0 atm g/mol) / (0.08205 L atm / (mol K) * 400 K) = 1.767 g / LQuestion 9:Cylindrical bar of moderately ductile stent metal is subjected to reversed and rotating-bending tests. If the metallic bar diameter is 6.0 mm, determine the maximum cyclic load that may be applied to ensure that fatigue failure will not occur. Assume that a factor of safety is 5.0, the distance between load-bearing points is 40 mm and yield stress of the metal is 266 MPa.