Mechanical properties and microstructures of commercially pure titanium (CP-Ti) developed by a newly designed multi-pass equal channel angular pressing (ECAP) process and cold drawing were investigated. The ECAP apparatus was developed in order to improve the efficiency of common ECAP and the performance of finished products. A much stronger CP-Ti billet was produced by using the proposed proce...

The study investigated the time course of the effects of acoustic and electric stimulation on the electrically evoked compound action potential (ECAP). Adult guinea pigs were used in acute experimental sessions. Bursts of acoustic noise and high-rate (5000 pulses/s) electric pulse trains were used as maskers. Biphasic electric pulses were used as probes. ECAPs were recorded from the auditory ne...

Plastic deformation of ARMCO iron processed by ECAP up to a maximum equivalent strain of sixteen (i.e., 1, 4, 8, and 16 ECAP passes) following route Bc was investigated by analyzing its microstructure and the stress-strain curves obtained after tensile tests at different levels of deformation. Three values of deformation (two in the plastic region taking into account the modified Crussard-Jaoul...

Technical purity Cu (99.95 wt%) polycrystals have been processed at room temperature by equal channel angular pressing. The results of mechanical tests and the microstructure characterization by various experimental techniques are presented. The yield stress as well as the strength were shown to increase with increasing strain and exceed the respective values of a coarse-grained material. The m...

Equal channel angular pressing (ECAP), expansion equal (Exp.-ECAP), and hybrid (HECAP) or (Hybrid ECAP) processes were applied to pure copper specimens within this study. After the application of ECAP, die used in Exp.-ECAP process was optimized considering strain inhomogeneity specimen maximum load that occurred during process. Finite element method (FEM), artificial neural network (ANN), gene...

Previous animal study revealed that post-implantation electrical detection levels significantly declined within days. The impact of cochlear implant (CI) insertion on human auditory pathway in terms of impedance and electrically evoked compound action potential (ECAP) variation within hours after surgery remains unclear, since at this time frequency mapping can only commence weeks after implant...

The influence of functional hair cells on electrical stimulation of the auditory nerve is an important issue as individuals with significant residual hearing are now cochlear implant candidates. Previous work has shown that chemical deafening during the course of acute experiments changes the auditory nerve's responses to electrical stimulation [Third Quarterly Progress Report, NIH contract N01...

Aluminum single crystal with 99.999% purity was deformed at room temperature by equal channel angular pressing (ECAP) up to 16 passes. Grain size and misorientation of processed samples were quantitatively characterized by TEM and EBSD. The results show that the refinement efficiency of high purity aluminum single crystal was poor in the initial stage. Extrusion by fewer ECAP passes (n ≤ 8) res...

HYPOTHESIS Limiting spatial overlap between electrical stimulation (ES) and acoustical stimulation (AS) in the cochlea reduces the effects of AS on electrically evoked auditory nerve activity. BACKGROUND Some hybrid cochlear implant systems have a regular array, whereas others have short arrays that spatially segregate ES from AS. AS settings in hybrid implants may also affect electroacoustic...