Effects of the fibers distribution in the human eardrum: A biomechanical study

The eardrum separates the external ear from the middle ear and it is responsible to convert the acoustical energy into mechanical energy. It is divided by pars tensa and pars flaccida. The aim of this work is to analyze the susceptibility of the four quadrants of the pars tensa under negative pressure, to different lamina propria fibers distribution. The development of associated ear pathology, in particular the formation of retraction pockets, is also evaluated. To analyze these effects, a computational biomechanical model of the tympano-ossicular chain was constructed using computerized tomography images and based on the finite element method. Three fibers distributions in the eardrum middle layer were compared: case 1 (eardrum with a circular band of fibers surrounding all quadrants equally), case 2 (eardrum with a circular band of fibers that decreases in thickness in posterior quadrants), case 3 (eardrum without circular fibers in the posterior/superior quadrant). A static analysis was performed by applying approximately 3000Pa in the eardrum. The pars tensa of the eardrum was divided in four quadrants and the displacement of a central point of each quadrant analyzed. The largest displacements of the eardrum were obtained for the eardrum without circular fibers in the posterior/superior quadrant.

A detector based on silica fibers for ion beam monitoring in a wide current range

A detector based on doped silica and optical fibers was developed to monitor the profile of particle accelerator beams of intensity ranging from 1 pA to tens of µA. Scintillation light produced in a fiber moving across the beam is measured, giving information on its position, shape and intensity. The detector was tested with a continuous proton beam at the 18 MeV Bern medical cyclotron used for radioisotope production and multi-disciplinary research. For currents from 1 pA to 20 µA, Ce3+ and Sb3+ doped silica fibers were used as sensors. Read out systems based on photodiodes, photomultipliers and solid state photomultipliers were employed. Profiles down to the pA range were measured with this method for the first time. For currents ranging from 1 pA to 3 µA, the integral of the profile was found to be linear with respect to the beam current, which can be measured by this detector with an accuracy of ∼1%. The profile was determined with a spatial resolution of 0.25 mm. For currents ranging from 5 µA to 20 µA, thermal effects affect light yield and transmission, causing distortions of the profile and limitations in monitoring capabilities. For currents higher than ∼1 µA, non doped optical fibers for both producing and transporting scintillation light were also successfully employed.

BMB Enterprises Inc. right-of-way request for a hydroelectric generating facility, Deep Creek Mountains, environmental assessment (EA).

Mode of access: Internet.

Chemfix Technologies, Inc. solidification/stabilization process : applications analysis report.

Mode of access: Internet.

Biological treatment of wood preserving site groundwater by BioTrol, Inc. : applications analysis report.

Mode of access: Internet.

Hearings on the Navy proposal to modify SSN-688 contracts with the General Dynamics Corp. (Electric Boat Division) and LHA and DD-963 contracts with Litton Industries, Inc./Litton Systems, Inc. (Ingalls Shipbuilding Division /

Mode of access: Internet.

Pioneer Vocational Industrial Services, Inc., Danville, Kentucky.

Mode of access: Internet.

Terror Lake project, no. 2743 - Alaska : applicant, Kodiak Electric Association, Inc. /

"August 1981."

Report to the President to investigate an unadjusted dispute between American Airlines, inc. : a carrier, and certain of its employees represented by the Air Line Pilots Association, International, a labor organization.

Sign: James Healy, Maynard E. Pirsig, Benjamin C. Roberts.

The development and application of automated and remote control telemetry for drinking water package plants : cooperative research and development agreement with George H. Drysdale & Associates, Inc..

Mode of access: Internet.

Development and evaluation of a pollution prevention technology for surface cleaning and decontamination : cooperative research and development agreement with Cold Jet, Inc.

Mode of access: Internet.

Study of fiber release during routine maintenance of asbestos containing floor tile : cooperative research and development agreement with Chemical Specialties Manufacturing Association, Inc.

Mode of access: Internet.