This dissertation addresses the design, simulation, prototype, and test of a new energy generation system, which transforms rotational motion into electricity by the use of an innovative turbine-generator. The system is divided in two assembled subsystems that interact to finally transform kinetic energy into electricity. The first subsystem is a miniaturized notched impulse turbine system, and the second one is a millimeter permanent magnet generator (PMG) assembled into the turbine. The conversion of biomechanical energy to electric energy, using clean and free energy produced by a living organism, is being increasingly researched [1]-[11]. These are all viable options, but advantages and disadvantages of each type of energy conversions should be evaluated individually to determine key factors such as efficiency as an energy harvesting method, the implementation cost, size, and the final applications where they will be used. Through this dissertation, a new option of green energy conversion is made available; focusing on the use of turbines to extract energy from microfluidics, with diverse application in biomedical, military/aerospace, and home areas. These systems have the potential of converting mechanical movement energy, and hydraulic energy into electric energy that may be sufficient for self-powering nano/micro devices and nano/micro systems. A flow, with constant pressure, a magnetic generator, and a novel impulse turbine design are combined to form a self-contained miniaturized generator system. The turbine consists of two main parts: a bearingless rotor and the enclosure or casing; while the miniaturized magnetic generator is a permanent magnet brushless machine, consisting of permanent magnets in a ring configuration and radial coils. A permanent pressure, from microfluidic pressure system, is the force used to move the blades. This rotational motion of the turbine is transformed into electricity using magnetic induction, formed by permanent magnets on the rotor and nine coils fixed in the holder of the turbine. The electricity is generated when the magnetic field rotates and moves past the conductor, which induces a current according to Faraday's Law [1-3]. The system has potential uses not only in medical equipment, but in automotive applications, home appliances, and aquatic and ventilation systems.

Objective: The air conduction click is currently the most widespread stimulus used to estimate the pure tone audiogram as part of auditory brainstem response (ABR) testing. The click is characterized by its broad spectral content and rapid onset, which may not make it the best choice for frequency specificity. An alternative stimulus is a short duration tone burst stimuli with notched noise masking. When obtaining an ABR using standard unmasked tone bursts, the brief stimulus onset may cause spectral splatter producing response contributions from unwanted regions of the cochlea; thus reducing the frequency specificity of the ABR. Notched noise masking used in conjunction with the tone burst ABR, limits the evoked response to those frequencies within the notch, thereby reducing the likelihood of spectral splatter and increasing frequency specificity. The presence of a sloping sensory hearing impairment creates additional difficulties for achieving frequency specificity because of the likelihood that lower frequency cochlea regions, with less sensory damage, will contribute to the evoked response. It is theorized that notched noise masking will reduce the neural contributions from regions of the cochlear outside those within the notch, resulting in more frequency specific results than those achieved with a standard unmasked tone burst stimulus. The present study was designed to investigate the differences in Wave V latency between the notched noise ABR and the standard unmasked tone burst ABR as a measure of frequency specificity. Design: Twenty-five participants with normal hearing in at least one ear and 16 participants with bilateral SNHL participated in this investigation. Each participant was given an audiological evaluation, a click ABR screening to determine neural synchrony, a standard tone burst ABR and a notched noise tone burst ABR. Results: An Analysis of Variance (ANOVA) failed to reveal any significant Wave V latency differences between the ABRs obtained with unmasked tone bursts versus ABRs obtained with a notched noise tone burst. Conclusion: The results of this study do not support the use of notched noise tone bursts for improved ABR frequency specificity. This finding is contrary to previously reported results (Stapells & Picton, 1981), which indicated improved frequency specificity when obtaining a tone burst ABR in notched noise versus a standard unmasked tone burst ABR.

Fatigue failures of driveline and suspensions components for ground vehicles under multiaxial loading conditions are common, since most those components are subjected to complex multiaxial loadings in service. In addition to the multiaxial loadings, many of those components contain notches and geometrical irregularities where the fatigue failure often occurs due to stress concentrations. Therefore, the origins of the multiaxiality can be related to various combinations of external loadings and notch geometries. A computational fatigue analysis methodology has been proposed here for performing multiaxial fatigue life prediction for notched components using analytical and numerical methods. The proposed multiaxial fatigue analysis methodology consists of an elastic-plastic stress/strain model and a multiaxial fatigue damage parameter. The multiaxial stress-strain notch analysis method originally proposed by Buczynski and Glinka is adapted to develop the elastic-plastic stress/strain model to compute local stress-strain responses using linear elastic FE results of notched components. An original multiaxial fatigue damage parameter based on the maximum fatigue damage plane is proposed to predict the fatigue life for notched components under multiaxial loadings. Results of the proposed multiaxial fatigue analysis methodology are compared to sets of experimental data published in the literature to verify the prediction capability of the elastic-plastic stress/strain model and the multiaxial fatigue damage parameter. Based on the comparison between calculated results and experimental data, it is found that the multiaxial elastic-plastic stress/strain model correlates well with experimental strain data for SAE 1070 steel notched shafts subjected to several non-proportional load paths. The proposed multiaxial fatigue damage parameter, when applied to the uniaxial loading to account for the mean stress effect on fatigue life, is found to correlate very well with four sets of experimental uniaxial mean stress fatigue data. In the case of multiaxial loadings, the proposed multiaxial fatigue damage parameter provides very good correlation with experimental fatigue data of thin-walled tube specimens of 1045 steel and Inconel 718. In addition, the proposed fatigue damage parameter is found to correlate reasonably well with experimental fatigue data of SAE 1045 steel notched shafts subjected to proportional and non-proportional loadings. The proposed multiaxial fatigue analysis methodology enables rapid durability evaluation for notched components design. The effect of changes in material, geometry and loads on the fatigue life can then be assessed in a short time frame. The proposed multiaxial fatigue analysis methodology provides more efficient and appropriate analysis methods preferable to very expensive experimental durability tests and more complex and time consuming life prediction methods using non-linear FE stress-strain analysis.

Fatigue failures of driveline and suspensions components for ground vehicles under multiaxial loading conditions are common, since most those components are subjected to complex multiaxial loadings in service. In addition to the multiaxial loadings, many of those components contain notches and geometrical irregularities where the fatigue failure often occurs due to stress concentrations. Therefore, the origins of the multiaxiality can be related to various combinations of external loadings and notch geometries. A computational fatigue analysis methodology has been proposed here for performing multiaxial fatigue life prediction for notched components using analytical and numerical methods. The proposed multiaxial fatigue analysis methodology consists of an elastic-plastic stress/strain model and a multiaxial fatigue damage parameter. The multiaxial stress-strain notch analysis method originally proposed by Buczynski and Glinka is adapted to develop the elastic-plastic stress/strain model to compute local stress-strain responses using linear elastic FE results of notched components. An original multiaxial fatigue damage parameter based on the maximum fatigue damage plane is proposed to predict the fatigue life for notched components under multiaxial loadings. Results of the proposed multiaxial fatigue analysis methodology are compared to sets of experimental data published in the literature to verify the prediction capability of the elastic-plastic stress/strain model and the multiaxial fatigue damage parameter. Based on the comparison between calculated results and experimental data, it is found that the multiaxial elastic-plastic stress/strain model correlates well with experimental strain data for SAE 1070 steel notched shafts subjected to several non-proportional load paths. The proposed multiaxial fatigue damage parameter, when applied to the uniaxial loading to account for the mean stress effect on fatigue life, is found to correlate very well with four sets of experimental uniaxial mean stress fatigue data. In the case of multiaxial loadings, the proposed multiaxial fatigue damage parameter provides very good correlation with experimental fatigue data of thin-walled tube specimens of 1045 steel and Inconel 718. In addition, the proposed fatigue damage parameter is found to correlate reasonably well with experimental fatigue data of SAE 1045 steel notched shafts subjected to proportional and non-proportional loadings. The proposed multiaxial fatigue analysis methodology enables rapid durability evaluation for notched components design. The effect of changes in material, geometry and loads on the fatigue life can then be assessed in a short time frame. The proposed multiaxial fatigue analysis methodology provides more efficient and appropriate analysis methods preferable to very expensive experimental durability tests and more complex and time consuming life prediction methods using non-linear FE stress-strain analysis.

The goal of this academic project was to study the effects of different variables on the damage progression around a central hole in carbon fiber composite coupon specimens. The tracked variables included the type of layup, stress ratio, stress levels, and damage mechanisms observed in each specimen. In-situ x-ray of the individual laminates recorded the extent of damage, mostly longitudinal splitting, as a function of the cycle count. The following lay-ups were included in the experiment: [45/90/-45/02/45/02/-45/0]s, [±5/65/(±5)2/-65/±5]s, and [±5/65/(±5)2/-65/5/65]s. More specifically, the objective of this study was to determine the stress levels at which detectable damage started to develop. The researchers chose to apply 50,000 cycles at each stress level and once damage was detected, the stress level was typically raised by 34.5 MPa (5 KSI), and then cycled another 50,000 cycles until damage exceeding 1.27 cm (0.50") in length was observed. Once the damage exceeded 1.27 cm (0.50"), cycling was continued to 1,000,000 cycles. Upon completion of the fatigue cycling, each specimen's residual strength was determined. The damage length versus stress level was plotted as a way to compare damage onset stresses and growth as a function of lay-up and stress ratio.

Dans le cadre de cette étude, l'influence du confinement de la plasticité en pointe de fissure sur la ténacité mesurée du matériau a été abordée. Après une étude de la microstructure du matériau, une étude expérimentale approfondie de son comportement mécanique a été mise en oeuvre. Un modèle complexe combinant un écrouissage anisotrope avec un endommagement lui aussi anisotrope comprenant une prise en compte de l'éffet de géométrie par le paramètre de Lode a été mis en place. L'ensemble des travaux se termine par une étude d'un cas concret de gazoduc entaillé soumis à une pression interne jusqu'à éclatement duquel on peut conclure que l'éprouvette de type SENT est plus adaptée que les autres pour l'étude du comportement de structures tubulaires minces. / In this thesis the influence of plastic constraint at a crack tip on the mesured tough-ness of a material has been evaluated. After a study of the microstructure of the material, an ex-perimental study of its mechanical behaviour was made. A complex model combining an anisotrope hardening with an anisotrope damage law including a geometry contridution by means of the Lode parameter was then used. The porject ends with a study of the bursting test of a precracked line pipe. We can conclude from this test that the SENT specimen is more suitable for the study of thin tubes.

The purpose of this study was to examine the prevalence and characteristics of audiograms that are notched (1) at 4,000 Hz and (2) at 3,000, 4,000, and/or 6,000 Hz. Bilateral audiograms from 1,000,001 veterans were obtained from Department of Veterans Affairs archives; after "cleaning" algorithms were applied, 744,553 participants (mean age = 63.5 yr) were included in the 4,000 Hz notch analysis (group 1) and 539,932 participants (mean age = 62.2 yr) were included in the 3,000, 4,000, and/or 6,000 Hz notch analysis (group 2). A notch was defined when the threshold at the notch frequency (3,000, 4,000, or 6,000 Hz) minus the 2,000 Hz threshold and the threshold at the notch frequency minus the 8,000 Hz threshold both were greater than or equal to 10 dB. In group 1, 77.1% did not have a notch at 4,000 Hz. In group 2, 65.3% did not have a notch at 3,000, 4,000, or 6,000 Hz; 12.4% had bilateral notches, 11.7% had left ear notches, and 10.7% had right ear notches. The notches were about twice as deep on the low-frequency side of the notch than on the high-frequency side. The mean left ear and right ear notch depths were about the same (23 dB), with mode notch depths in the 15.0 to 17.5 dB range.

The purpose of this study was to examine the prevalence and characteristics of audiograms that are notched (1) at 4,000 Hz and (2) at 3,000, 4,000, and/or 6,000 Hz. Bilateral audiograms from 1,000,001 veterans were obtained from Department of Veterans Affairs archives; after "cleaning" algorithms were applied, 744,553 participants (mean age = 63.5 yr) were included in the 4,000 Hz notch analysis (group 1) and 539,932 participants (mean age = 62.2 yr) were included in the 3,000, 4,000, and/or 6,000 Hz notch analysis (group 2). A notch was defined when the threshold at the notch frequency (3,000, 4,000, or 6,000 Hz) minus the 2,000 Hz threshold and the threshold at the notch frequency minus the 8,000 Hz threshold both were greater than or equal to 10 dB. In group 1, 77.1% did not have a notch at 4,000 Hz. In group 2, 65.3% did not have a notch at 3,000, 4,000, or 6,000 Hz; 12.4% had bilateral notches, 11.7% had left ear notches, and 10.7% had right ear notches. The notches were about twice as deep on the low-frequency side of the notch than on the high-frequency side. The mean left ear and right ear notch depths were about the same (23 dB), with mode notch depths in the 15.0 to 17.5 dB range.

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Yes / A compact planar monopole antenna is proposed for ultra-wideband applications. The antenna has a microstrip line feed and band-rejected characteristics and consists of a ring patch and partial ground plane with a defective ground structure of rectangular shape. An annular strip is etched above the radiating element and two slots, one C-shaped and one arc-shaped, are embedded in the radiating patch. The proposed antenna has been optimized using bio-inspired algorithms, namely Particle Swarm Optimization and the Firefly Algorithm, based on a new software algorithm (Antenna Optimizer). Multi-objective optimization achieves rejection bands at 3.3 to 3.7 GHz for WiMAX, 5.15 to 5.825 GHz for the 802.11a WLAN system or HIPERLAN/2, and 7.25 to 7.745 GHz for C-band satellite communication systems. Validated results show wideband performance from 2.7 to 10.6 GHz with S11 ˂ -10 dB. The antenna has compact dimensions of 28 × 30 mm2. The radiation pattern is comparatively stable across the operating band with a relatively stable gain except in the notched bands. / This work was supported in part by the United Kingdom Engineering and Physical Science Research Council (EPSRC) under Grant EP/E022936A, TSB UK under grant application KTP008734 and the Iraqi Ministry of Higher Education and Scientific Research.