In this work full parametric analysis of nano antennas is presented. To begin with, optical or electronic properties of noble metals such as gold and copper were studied in details to get a clear understanding of their reaction to an incident electromagnetic wave. Complex frequency dependent dielectric functions indicated that in THz metals acts as a dielectric with significant absorption. Simultaneous optimization of the length and the bow angle of a bow-tie antenna resulted in relative electric field intensity enhancement of 8 orders of magnitude for 0.5nm gap and 4 orders of magnitude for 50nm around 28THz resonance frequency. These results are at least 2 orders of magnitude greater than the published optical antennas. Physical reasons behind field localization and intensity enhancement  are  discussed  in  details.  The  solution  of  Maxwell’s  equations  at   the  interface between metallic nano antenna and air is also present in this piece of research. The derived dispersion relation of surface plasmons shows momentum matching at 28.3 THz between free propagating electromagnetic fields’ modes in air and localized modes at the interface. Consequently, Propagating electromagnetic waves are ensured to couple to localized surface propagating modes producing filed enhancement. The integrated SiO2 matching section is theoretically proven to increase transmission to substrate to 75% (compared to 40% without it) which in turn improves the coupled power by 40 times. Nano antennas were fabricated in house using Electron beam lithography with a precise gap of 50nm. In addition, THz diode was designed, fabricated and integrated to the nano antennas to rectify the enhanced THz signal. The integration of the nano diode required a precise overlap of the two arms of the antenna in the rage of 100nm. In order to overcome two arms overlap fabrication challenges, three layer alignment technique was used to produce precise overlap.The THz rectifier was electrically tested and shown high sensitivity and rectification ability without any bias. Finally, nano antenna integrated diode is under optical testing using a 10.6μm Co2 laser at Electro-Optics Lab, Prince Sultan Advanced Technologies Research Institute (PSATRI), King Saud University due to the unavailability of the measurement setup in KAUST.

Due to the expanding aging population, Masters sport is becoming an increasingly popular activity for older adults (Weir et al., 2010). However, few resources are available to support lifelong sport adherence for middle-aged and older adults in competitive sport, or Masters athletes (MAs). The purpose of the thesis was to explore how MAs apply deliberate psychological strategies as a support to enhance their performance, experience, or adherence to the adult sport lifestyle. It also explored how mental performance consultants (MPCs) viewed the application of sport psychology to MAs, including content to which skills/strategies could be applied, and delivery approaches. In Manuscript 1, semi-structured interviews were conducted with eight Canadian MAs (Mage = 51, range 38-62; 3 males, 5 females) from 12 sports (10 individual, 2 team) to explore how they applied psychological skills/strategies as a support to the Masters sport experience. Data were thematically analyzed (Braun & Clark, 2012) deductively (Weinberg & Gould, 2015) and inductively. The results demonstrated that MAs used traditional mental skills predominantly to enhance performance, while novel Masters-specific skills were used to maintain sport adherence. MAs promptly illustrated sport psychology content, but were rather limited when discussing their methods/techniques. In Manuscript 2, five two-person semi- structured group interviews were pursued with ten professional Canadian MPCs (8 women, 2 men) who had experience consulting MAs. These interviews explored the content consultants delivered to MAs and whether there were implications of specific adult attributes associated with service delivery. Data were thematically analyzed (Braun & Clark, 2012) inductively. The results showed MPCs’ perceptions on psychological content they believed was highly pertinent in their consulting practice with MAs. Specifically, they described targeted content related to performance readiness, prioritizing sport, protecting/recovering sport enjoyment, and aging/self-compassionate considerations. MPCs also highlighted nuances related to approaches to consultation with adult sportspersons and the delivery of psychological services to MAs. In both studies with the MAs and the MPCs, interviewees described various barriers and constraints that influenced approaches to consultation and service delivery. Altogether, the corroborative results from both studies suggest the benefits of psychological support services for MAs, the use of MPCs’ services and expertise as an additional support to maintain lifelong sport activity, and provide a formative guide for content and approaches to delivery with the Masters clientele.

Petrophysical interpretation of 1H NMR relaxation responses from saturated rocks is complicated by paramagnetic species present in fluids. Oxygen dissolved in liquids is one common example. Dipolar interactions of oxygen’s unpaired electron spins with the magnetic moment of fluid nuclei provide a strong relaxation mechanism known as paramagnetic relaxation enhancement (PRE). As a result even low concentrations of dioxygen in its common triplet ground state significantly shorten longitudinal and transverse relaxation times of host fluids. This effect may be employed similarly to any standard tracer technique to study pore connectivity in porous media by detecting a change of oxygen concentration due to diffusion resolved in time and space. Since relaxation enhancement effect is likely stronger in non-wetting phase than in wetting one (where surface relaxation process dominates) this difference can be utilized to study wettability in immiscible multiphase systems. We use a relaxation time contrast between air-saturated and oxygen-free fluids to evaluate oxygen concentration change within two fluid phases saturating rock, to estimate time required to establish equilibrium concentration and to calculate a mutual diffusion coefficient of oxygen. A spatially- and time-resolved T2(z,t) experiment provides the time-dependent oxygen concentration change along the fully- and partially-saturated carbonate core plug exposed to air saturated oil at its inlet. We derive an effective mutual diffusion coefficient of oxygen and accordingly a tortuosity estimate as a function of position along the core and rock saturation. The spatially resolved oxygen diffusion-based tortuosity is compared to simulated conductivitybased tortuosity. The latter is calculated on a high-resolution micro-tomographic image of Mount Gambier limestone by solving the Laplace equation for conductivity.

The speech auditory brainstem response (sABR) is a promising technique for assessing the function of the auditory system. This non-invasive technique has shown utility as a marker of central processing disorders, some types of learning difficulties in children, and potentially for fitting hearing aids. However, the sABR needs a long recording time to obtain a reliable signal due to the high background noise, which limits its clinical applicability. The objective of this work is to develop methods to detect the sABR in high background noise and enhance it based on a modeling approach and through experimental testing. First, sABR noise estimation based on LQ/QR decomposition is derived, and its mathematical proof is shown. Second, an autoregression model is used to estimate the single-trial sABR which is then used to test several sABR detection and enhancement methods. Third, a novel Artificial Neural Network (ANN) based detection approach is proposed and compared using modeled and recorded data to other detection methods in the literature: Optimal Linear Filter (LF), Online Estimator (OE), Mutual Information (MI) and Artificial Neural Network based on the Discrete Wavelet Transform and Approximate Entropy (ANN DA). Finally, comprehensive evaluation of several sABR enhancement methods is performed, based on the Wiener Filter (WF), Maximum-SNR Filter (Max-SNR), Adaptive Noise Cancellation (ANC) with Least-Mean-Square (LMS), Affine Projection (AP) and Recursive-Least-Square (RLS) adaptation algorithm. The results show that the developed LQ/QR decomposition estimated noise is similar to the actual noise, and the modeled data are statistically similar to the recorded data. Moreover, the proposed ANN-based detection method is more accurate and requires less processing time than other methods, and the comprehensive evaluation of enhancement methods shows that RLS has best overall performance in enhancing the sABR. Therefore, the methods developed and evaluated in this work have the potential to reduce the required recording time for the sABR, and thus make it more practical as a clinical tool.

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Phased array systems present desirable antenna features like beam steering and high gain. However, due to their high cost, civilian applications cannot generally afford them, restricting their usage to military. Hardware involved in phased array systems is expensive and the number of devices is high, since there is usually one device of each kind (filter, amplifier, shifter..) for each individual antenna. Alternative techniques, mainly based on TDMA, have been developed looking for lowering the number of elements in the system. However, these approaches increase the system bandwidth, multiplying it by a factor of $N$ (Number of antennas), as they use redundant information. In this thesis, a novel phased receiver, based on an economic sampling scheme is proposed. All the elements in an array receive a common information (signal amplitude) and a unique information (relative delay between elements). The idea is to sample only the information required to reconstruct the transmitted signal and discard the redundant one. This idea is achieved by sampling just one antenna during each RF cycle and then gathering all the information taking in account the relative delay between different antenna elements. The proposed technique is mathematically proved and validated by simulation. As a first approach, the equation for the received signal in the frequency domain is derived for a linear array. The radiation pattern and the received signals are simulated for equally spaced planar and linear arrays. Bandwidth signal transmission is demonstrated and tapering effects are shown. After that, the proposed technique is expanded for arbitrary structures and the resulting system bandwidth is enhanced by using different sampling order sequences. / Master of Science

Accurate determination of the surface enhanced Raman scattering (SERS) enhancement factor (EF) is critically important for a fundamental understanding of the SERS phenomenon. Experimental quantification of SERS EFs is challenging. A series of instrument-, analyte-, and SERS-substrate related issues can affect the SERS intensity and thus compromise the reliability of the measured SERS EFs. This dissertation presents a series of computational and experimental studies that enhance the quantitative understanding of the SERS signal variation and identify ways to enhance the reliability of the SERS EF determination. Chapter I presents an overview of works described in this dissertation. The gold nanoparticle (AuNP) inner filter effect on SERS measurements is demonstrated in Chapter II. Using dithiopurine and ethanol as model analytes, we demonstrate that the nanoparticle will modify the analytes’ Raman signal through two competitive mechanisms: enhancing the Raman signal of the analyte on the nanoparticle surface through electromagnetic enhancement, and attenuating the analyte Raman signal through photon extinction. The significance of the AuNP inner filter effect is quantitatively evaluated using ethanol as the internal reference. A solvent internal reference method is presented in Chapter III for quantifying the SERS EFs of analytes adsorbed onto AuNPs and AgNPs. One of the key findings is that while an analyte’s SERS EF varies significantly as a function of nanoparticle aggregation, its peak SERS EF depends only on the types and sizes of nanoparticles, but not on experimental conditions including concentrations of analyte, nanoparticle, and aggregation reagent. Chapter IV presents a SERS internal reference method for the determination of the resonance Raman EFs in the SERS study of rhodamine 6G (R6G) adsorbed onto AuNPs and AgNPs. The most striking finding is that the AgNP binding reduces, instead of enhancing, the R6G resonance enhancement. Finally, the wavelength-dependent correlation between UV-vis intensities and SERS EFs of aggregated AuNPs and AgNPs were investigated under three fixed excitation wavelengths (532, 632, and 785 nm). The nanoparticle UV-vis intensity is an excellent indicator for identifying the optimal aggregation state for AgNP-based SERS acquisitions under each of the three excitation wavelengths and for the AuNP-based SERS under a 632 nm excitation.

A novel experimental technique has been developed for measuring the light trapping enhancement and the carrier recombination lifetime in silicon wafers. The technique is based on the pump/probe modulated free carrier absorption (MFCA) method, where the probe beam, attenuated by generated free carriers, carries information about the effective lifetime and the average light path enhancement in a textured silicon wafer. For the first time, a reflection mode MFCA technique is presented where the reflected part of the probe beam is used to perform measurements, while the conventional technique is based on measurements of the transmitted part of the probe beam. A theoretical model is presented to explain the behavior of the light beam in double-side polished and double-side textured silicon wafers. The model yields good agreement with the experimental results and explains the difference in the amplitudes of the reflected and transmitted signals. The results of the experimental measurements of the light path enhancement in a double-side textured sample are analyzed and the reasons for their deviation from the Lambertian limit are discussed. This work presents new applications of the MFCA technique and shows how it can be used for the simultaneous determination of more than one crucial characteristic of silicon solar cells. / Thesis / Master of Applied Science (MASc)

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