Because of their net negative charge, bacteria are easily attracted to and adhere to surfaces on...

  

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Because of their net negative charge, bacteria are easily attracted to and adhere to surfaces on which they can proliferate, forming bacterial biofilms, thin films of bacteria coating the surface. Bacterial biofilms are especially problematic on indwelling medical devices (IMDS), which are devices inserted into a patient and include catheters, heart valves, and artificial joints. Contaminated IMDS are the most common source of infection in humans. A number of mitigation methods are in use today, including antibacterial graphene oxide coatings and the use of electric fields and surface charges to repel bacteria. In a hospital operating room, due to an unexpected complication in the surgical procedure, and in violation of protocol, a catheter that was removed from its sterile pouch before the complication is being used hours after being exposed to the air in the room. The catheter, which can be modeled as an insulating cylindrical shell with a length = 40.0 cm, inner radius a = 1.75 mm and outer radius b = 3.00 mm, is coated with a thin bacterial film. The film has resulted in a uniform charge density of -0.700 μC/m2 on the outer surface of the catheter. Calculate the magnitude (in N/C) and direction of the electric field generated near the centerpoint of the length of the catheter by the distribution of biofilm at a radial distance of 1.00 mm, 2.50 mm, and 5.00 mm from the central axis of the catheter. (Assume the positive direction is outward. Indicate the direction with the signs of your answers.) What If? After a long time, biofilm can also form on the inner surface of the catheter. If a film of charge density -0.300 μC/m2 has formed on the inner surface of the catheter, what is now the magnitude (in N/C) and direction of the electric field at a distance of 1.00 mm, 2.50 mm, and 5.00 mm from the central axis of the catheter? (Assume the positive direction is outward. Indicate the direction with the signs of your answers.) Because of their net negative charge, bacteria are easily attracted to and adhere to surfaces on which they can proliferate, forming bacterial biofilms, thin films of bacteria coating the surface. Bacterial biofilms are especially problematic on indwelling medical devices (IMDS), which are devices inserted into a patient and include catheters, heart valves, and artificial joints. Contaminated IMDS are the most common source of infection in humans. A number of mitigation methods are in use today, including antibacterial graphene oxide coatings and the use of electric fields and surface charges to repel bacteria. In a hospital operating room, due to an unexpected complication in the surgical procedure, and in violation of protocol, a catheter that was removed from its sterile pouch before the complication is being used hours after being exposed to the air in the room. The catheter, which can be modeled as an insulating cylindrical shell with a length = 40.0 cm, inner radius a = 1.75 mm and outer radius b = 3.00 mm, is coated with a thin bacterial film. The film has resulted in a uniform charge density of -0.700 μC/m2 on the outer surface of the catheter. Calculate the magnitude (in N/C) and direction of the electric field generated near the centerpoint of the length of the catheter by the distribution of biofilm at a radial distance of 1.00 mm, 2.50 mm, and 5.00 mm from the central axis of the catheter. (Assume the positive direction is outward. Indicate the direction with the signs of your answers.) What If? After a long time, biofilm can also form on the inner surface of the catheter. If a film of charge density -0.300 μC/m2 has formed on the inner surface of the catheter, what is now the magnitude (in N/C) and direction of the electric field at a distance of 1.00 mm, 2.50 mm, and 5.00 mm from the central axis of the catheter? (Assume the positive direction is outward. Indicate the direction with the signs of your answers.)