Stimulated quantum phase slips from weak electromagnetic radiations in superconducting nanowires

We study the rate of quantum phase slips in an ultranarrow superconducting nanowire exposed to weak electromagnetic radiations. The superconductor is in the dirty limit close to the superconducting-insulating transition, where fluxoids move in strong dissipation. We use a semiclassical approach and show that external radiation stimulates a significant enhancement in the probability of quantum phase slips. This can help to outline a new type of detector for microwave to submillimetre radiations based on stimulated quantum phase slip phenomenon.Comment: 10 pages, 9 figure

Exciton-photon interaction in a quantum dot embedded in a photonic microcavity

We present a detailed analysis of exciton-photon interaction in a microcavity made out of a photonic crystal slab. Here we have analyzed a disk-like quantum dot where an exciton is formed. Excitonic eigen-functions in addition to their eigen-energies are found through direct matrix diagonalization, while wave functions corresponding to unbound electron and hole are chosen as the basis set for this procedure. In order to evaluate these wave functions precisely, we have used Luttinger Hamiltonian in the case of hole while ignoring bands adjacent to conduction band for electron states. After analyzing Excitonic states, a photonic crystal based microcavity with a relatively high quality factor mode has been proposed and its lattice constant has been adjusted to obtain the prescribed resonant frequency. We use finite-difference time-domain method in order to simulate our cavity with sufficient precision. Finally, we formulate the coupling constants for exciton-photon interaction both where intra-band and inter-band transitions occur. By evaluating a sample coupling constant, it has been shown that the system can be in strong coupling regime and Rabi oscillations can occur for Excitonic state population.Comment: Journal of Physics B: Atomic and Molecular Physics (to appear

Medial Zones: Theory, Computations and Applications For Rigid and Non-Rigid Solids

The popularity of medial axis and other geometric skeletons in shape modeling and analysis comes from several of their well known fundamental properties. For example, they capture the connectivity of the domain, have lower dimension than the space itself, and are closely related to the distance function constructed over the same domain. In this Ph.D. dissertation, we formally define the new concept of medial zone of any 2- or 3-dimensional semi-analytic domain that subsumes the medial axis of the same domain as a special case, and can be thought of as a \u27thick\u27 skeleton having the same dimension as that of the domain. The medial zone can converge to either medial axis or the main space itself, and is homeomorphic to the domain. Our formulation of medial zones of any semi-analytic domain reveals their attractive theoretical and computational properties, including efficient computational framework for rigid or evolving boundaries. ^ The approach presented in this thesis provides a unified framework for computing medial zones together with a wide range of geometric skeletons for any arbitrary 2- or 3-dimensional domain. We show that medial zones combine some of the critical geometric and topological properties of both the domain and of its medial axis, and that re-formulating problems in terms of medial zones is advancing the state of the art technologies in many geometric intensive applications. To illustrate this, we focus on path planning for robotics, and shape synthesis of mechanical parts. In path planning we demonstrate the significant improvements in the quality of the path as well as on the computational burden. For design automation, medial zones connect all the energy ports due to their guaranteed topological properties, and can be used to construct a feasible shape satisfying prescribed boundary conditions. Moreover, the new concept of medial zone can open significant new directions in geometric computing and is providing a common computational framework for many geometric intensive applications.

HEARING AID USE IN PATIENTS WITH PRESBYACUSIS: A QUESTIONNAIRE SURVEY

The acceptability of hearing aids in people with presbyacusis has been improved but assessment of whether there is a need for more counseling to increase the number of regular hearing-aid users seems to be important. The aim of this study was to determine if the hearing aid was worn regularly and over a long period of time in people with presbyacusis. A questionnaire survey of patients with presbyacusis who had been fitted with a monaural behind the ear hearing aid for the first time was undertaken. The patients were divided into four groups ranging from 6 months to 3 years after fitting. Overall regular long-term use of the hearing aid was found in the majority of patients with presbyacusis. The main dropout point was within the first year after fitting the hearing aid. The study furthermore revealed a relatively high demand for further help and advice with the hearing aid in all groups

Novel User-friendly Device for Human Bite Force Measurement

Statement of Problem: Bite force is generated due to the consonance between different parts of the masticatory system. In dentistry, measurement of the bite force is quite common through several methods and devices. Objective: The aim was to present a novel bite force-measuring device that could help reducing the costs. Materials and Methods:This study presented the design, fabrication, and calibration method of a novel low-cost bite force-measuring device based on a force-sensitive resistor and application of strain gages. The FSR 402 was the selected sensor, which was suitable in size for placement in mouth, sterilizable for reuse, and contained biocompatible material.It could measure a large bite force of up to 90 kg with high repeatability.The device had a liquid crystal display (LCD) for immediate visualization of the results and a system for quick calibration of the device in office. To assess the accuracy of the device, some forces were applied to the sensor in nine values from11 to 80kg. The mean of measured force, absolute error, and error percentage were measured and recorded. Results: The mean relative error was almost 2% within the range of 11-80kg. The lowest error percentage was 0.46% at the load of 52kg and the highest error percentage was 3.97% at the load of 28 kg.Error percentage was 2.51% in the lowest range (11kg) and 2.65% in the highest range (80kg).The relative error in different ranges did not follow a particular trend. Conclusions:The bite force-measuring device is an economical and user-friendly appliance that can be simply used for routine practice in the office. The device shows good linearity and repeatability. It also has a calibration apparatus that can help maintaining the device accuracy

Evaluation of saccular function pre-post cochlear implant surgery using VEMPs

Objectives: The aim of present study was evaluation of saccular function in cochlear implant candidates with severe to profound sensory neural hearing loss. Before and after cochlear implantation Methods: In this study 35 Cochlear Implant (CI) candidates with bilateral severe to profound sensory neural hearing loss before and about 30 days after cochlear implantation and 20 normal-hearing cases as a control group underwent VEMP test. Both groups were matched based on gender and age. Results: VEMP responses were absent bilaterally in 10 out of 35 patients. 4 patients were excluded from the study because they did not receive CI during present study. From 21 remaining patients, 5 cases lost VEMP response in their implanted ear after surgery. In control group, VEMP responses were present bilaterally. Discussion: The results of present study show that saccular dysfunction in CI candidates is extremely probable and this is possible that saccule get impaired after CI