Doctor of Philosophy (Ph.D.), University of Dayton, 2025, Electrical Engineering

The Electro-Optical (EO) effect refers to the change in the optical properties of a material in response to a slowly varying external electric field compared to optical frequencies. This effect is key in EO modulators and beam steerers, which utilize the medium's linear or quadratic EO effect to modulate or steer light. A traveling-wave Mach-Zehnder modulator (TW-MZM) is used in optical communications for rapid and efficient light modulation, with a longer interaction region ideal for high-speed applications compared to lumped-element versions. On the other hand, the EO beam steerers use either an optical phased array (OPA) based on an EO thin film or a bulk EO crystal. Despite advantages like speed, robustness, and compactness, the EO steerers have limited angles, apertures, and high production costs. OPAs also struggle with low diffraction efficiency and dispersion, while bulk crystals are crystal polarization-dependent and require high voltages. To overcome or mitigate some of those drawbacks, this dissertation aims to tackle the following five key questions that have remained unresolved in the field of EO beam steerers for decades. How can bulk EO crystals be used for fast deformable mirrors, various types of varifocal lenses, and nonmechanically steer a large aperture light to a wide angle? How to increase the efficiency of OPAs and overcome the dispersion? How to make the OPAs manufacturable due to the very large number of electrodes? How to steer a large aperture continuously to a wide angle with OPAs? How can light be steered in a mechanical and non-mechanical hybrid manner to direct it mechanically and scan within a small area non-mechanically, or to perform back scanning non-mechanically? This approach is particularly relevant in space applications, where back scanning may be important to account for delays caused by the speed of light. The first section of the research provides a detailed exploration of a bulk SBN75 single crystal - known for (open full item for complete abstract)

MS, University of Cincinnati, 2020, Engineering and Applied Science: Civil Engineering

Changes have been made in the coupling beam wall connection design for Composite Ordinary Shear Wall in AISC seismic provision 341. According to the latest seismic provision AISC 341-16, the coupling beam wall connection is to be designed and detailed to develop the linear elastic shear demand of the coupling beam. Before this revision, the coupling beam wall connection was designed and detailed to develop the expected strength of the beam. The results from an analytical study have demonstrated that embedment length of coupling beams for stories with low elastic demand could have very short embedment lengths. Although such short embedment lengths satisfy the code, they could have detrimental effects. It is important to note that most of the experimental investigations forming the basis of H4 and H5 section of AISC 341-16 were focused on high seismic demands. Due to lack of information regarding the performance of coupled core wall systems subjected to wind loads and low seismic loads, an experimental study is necessary to develop much needed data for such loads. The test results will fill a major gap in the existing knowledge base and can be used to modify the current seismic provisions of AISC seismic provisions for Composite Ordinary Shear Wall. The pending experimental and analytical studies will be formulated based on this M.S. thesis.

Master of Science, The Ohio State University, 2020, Welding Engineering

High energy density welds are often used in critical applications involving a wide range of structural materials. In most cases, both laser and electron beam welding may be considered for these applications and the ability to use both processes to make comparable welds in terms of both weld profile and microstructure provides considerable process selection flexibility. In this study, autogenous, partial penetration welds on 304 SS, 304L SS, and Ti-6Al-4V were made using both fiber laser and electron beam processes. The main variables of interest, power and travel speed, were varied independently. Beam characterization was performed to determine parameters necessary for similar welding conditions between the two processes. Overfocused electron beams produced a more Gaussian distribution than underfocused beams. Laser beam characterization showed a slight increase in sharp spot size with increasing power, likely due to machine capabilities. Welds were made using sharp focus for laser welds and both a sharp, deflected beam and an overfocused beam for electron beam welds. Depth of penetration varied substantially between process conditions, but a similar trend between processes was observed when comparing area of the fusion zone, suggesting a similar melting efficiency. For defocused electron beam welds, increases in voltage yielded a dip in penetration for increasing power. This was likely due to complications with the machine or the diagnostic tool resulting in a narrower beam at lower voltages. A reduction in melting efficiency was observed in Ti-6Al-4V laser welds as compared to EB welds, likely due to vaporization effects, material properties, or both. Analysis of the depth of penetration for 304L and Ti-6Al-4V laser welds at varying powers and travel speed yielded predictive process maps. Stainless steel alloys showed consistent microstructures with work found in literature for pulsed laser welding. Limited metallographic analysis for Ti-6Al-4V welds was conducte (open full item for complete abstract)

Master of Science (MS), Wright State University, 2017, Physics

The determination of a flattening filter free (FFF) beam profile when the collimator is intentionally modified to incorporate a physical wedge. Specifically, radiation beam profiles change shape when a metallic wedge is placed in the path of the beam. Examination of this unknown is necessary to ascertain whether a physical wedge is clinically beneficial for applications involving FFF beams. The aim of this study is to determine if the radiation profile of a flattening filter free beam having a physical wedge is comparable to a beam with a flattening filter, with the same wedge inserted. This research involves measurement of relative dose along the wedged plane. A commercially available particle accelerator was used for this study, which was capable of producing 6 MV bremsstrahlung x-rays. Only beams operating at 6 MV were considered for the investigation. The results indicate that Wedged profiles are similar in many respects when a FFF beam uses the same physical wedge designed for flattening filter beams. Differences in wedged profiles between the FFF and FF beams are discussed.

Master of Science in Biomedical Sciences (MSBS), University of Toledo, 2017, Biomedical Sciences (Medical Physics: Radiation Oncology)

RayStation, a new treatment planning system (TPS), was purchased and recently commissioned for clinical use by the institution. As part of the commissioning process, an accurate model of the TrueBeam linear accelerator was made prior to clinical acceptances. Data collection, importing measurements, beam modeling, point dose verifications and clinical plan comparisons are procedures that must be done in order to complete the commissioning of photon and electron energies. During the beam modeling process, various parameters were modified to achieve close matches between the computed and measured PDD curves, as well as measured and computed beam profiles. The tolerance objectives were to have computed data deviating from the measured data within the 2% in fall-off regions, 3% tolerance within in-field and out-of-field regions, and 10% tolerance in build-up regions and penumbra regions [1]. The dosimetric validation procedure followed. Point dose measurements were completed using both the ArcCHECK phantom and the water tank. The majority of the results met the set criteria except for some measurements blocked by MLC leaves or jaws when taken adjacent to the edge of fields. To further confirm the goodness of modeled beams, clinical treatment plans developed with the previously clinically commissioned Pinnacle TPS and imported into the RayStation TPS to generate new plans with same beam arrangements and control points and used as comparisons. After clinical commissioning was completed for RayStation software, a feasibility of using FFF beams to deliver identical or superior beam profile provided by conventional flattened beams of the same energy was investigated. The objective of this research was to show that through sliding window treatment planning, one can create optimized plans and hence no longer the technology of flattening filter is required in modern linear accelerators. To explore this topic, a two stage analysis was carried out. First, delivering dose (open full item for complete abstract)

Doctor of Philosophy, The Ohio State University, 2022, Electrical and Computer Engineering

The real-time applications and the IoT promote the need for a newer idle spectrum to support the required high traffic. This pushes toward the emergence of the millimeter-wave (mmWave) and the sub-Terahertz (sub-THz) bands in wireless communication. Albeit these higher frequency bands offer wide spectrum help improving the spectral efficiency, it comes with the challenge of alleviating the severe attenuation. MmWave transceivers use large antenna arrays to form high-directional beams and overcome severe attenuation. A large array size leads to a costly beam alignment process if no prior information about beam directions is available. Beam alignment has two phases: beam discovery, and beam tracking. Beam discovery is finding the beam direction by consuming several pilot symbols to find the optimum direction. Moreover, beam tracking is a common approach to keep the discovered beams tightly coupled without frequent beam discovery to eliminate the overhead associated with realignment. Both phases become more difficult as the beams get narrower since slight mismatches lead to significant degradation in SNR as the beam coherence times are short. As a result, beams may lose alignment before they can be readjusted periodically with the aid of pilot signals. In this thesis, we introduce two complementary proposals. The first proposal is for the issue of beam tracking, and the second proposal is for the issue of beam discovery. In the first part of the thesis, we propose a model where the receiver adjusts beam direction continuously over each physical-layer sample according to a carefully calculated estimate of the continuous variation of the beams. Our approach contrasts the classical methods, which fix the beams in the same direction between pilots. In our approach, the change of direction is configured using the estimate of variation rate via two different methods; a Continuous-Discrete Kalman filter and an MMSE of a first-order approximation of the variation. Our method (open full item for complete abstract)

Master of Science in Engineering, University of Akron, 2022, Civil Engineering

This paper details the research analyzing the effects of monotonic and cyclic loading on beam-end specimens with corrosion. The test consisted of 44 beam-end specimens tested in a vertical setup with a 55-kip actuator. Each step of the experimental process from specimen design, concrete cast and curing, accelerated corrosion procedure, and testing of each specimen are described in this paper. The variables that were the focus of this study were: Concrete cover (ranging from 1in to 3in), diameter size of rebar (#5, #6, and #8), presence of transverse stirrups, corrosion level (0%-20%), and the ratio of concrete cover to the diameter of the rebar. Additionally, Sajedi and Huang's (2015) bond strength model was evaluated for its accuracy in predicting the bond strength. Finally, each variable was analyzed to determine the impact they had on the failure modes (splitting or pull-out) for reinforced concrete.

PHD, Kent State University, 2021, College of Arts and Sciences / Materials Science Graduate Program

In this dissertation, a novel approach to a liquid crystal electro-optical device for light beam steering is examined. The proposed apparatus, so called "FFS-PPD", with fast switching variable phase and tunability is successfully developed for the first time. The device was first designed, analyzed and optimized with the help of modeling. It was then fabricated and the proof of concept was demonstrated by characterization.Other types of liquid crystal optical devices such as Pancharatnam-Berry phase lens (PPL) and segmented phase profile (SPP) variable focal lens and their emerging applications in AR/VR/3D systems are also discussed.

Master of Science in Engineering, Youngstown State University, 2020, Department of Civil/Environmental and Chemical Engineering

In any civil engineering structure, damage resulted from the construction phase or developed over time affects the structural performance and may result in its failure. Early-stage damage detection is necessary for maintaining structural safety, serviceability, and minimizing the cost throughout the structural operation. Various destructive and conventional non-destructive damage detection techniques employed over the years are either laborious or, uneconomical, and require access to the entire structure. These limitations were addressed by developing the vibration-based methods for regular structural health monitoring. This holistic approach includes analyses of vibration signals and the related modal parameters. The change in these parameters may be used for detection of damage. In this research, modal frequency was used as a parameter to detect damage. The objective is to identify damage using natural frequency. To achieve this objective, several tests were conducted on simply supported steel beams having an open transverse crack with varying depths and locations. The analytical, numerical, and experimental approaches generate frequencies for the first three vibrating modes. The analytical approach considered the beam as the Euler-Bernoulli beam. Analytical frequencies were found from the solution of a partial differential equation by applying the boundary conditions. Vibration signals collected from the portable digital vibrometer (PDV 100) were analyzed using the Fast Fourier Transform (FFT) technique to achieve modal frequencies of the steel beam. In ANSYS (ANSYS, 2017), the finite element models of the beams were calibrated using the experimental results. The frequency from the analytical approach depends on the crack depth. Therefore, this method cannot produce the actual frequency of a beam with varying damage locations and depths. The graphical plots of the normalized frequency with varying damage depth and damage location was used to study the impact o (open full item for complete abstract)

Master of Sciences, Case Western Reserve University, 2017, Physics

The historical and current market trends for transparent conductive coating are considered. The metal oxide transparent conductive coatings are found to have all but reached their theoretical limits. In light of this background, a coating process that was developed for an electron-beam deposition chamber at VisiMax Technologies is described. The coating process is shown to be capable of depositing an ITO film that is on par with the protective coatings that are currently on the market. The protective coating market is investigated and found to be sufficiently large for a specialized thin film-coating firm to enter. The ITO film that was produced by this process had a sheet resistance of 62 ohm-squares and an average transmission through the visible range (400nm – 700nm) of 89.4%.

Master of Science (M.S.), University of Dayton, 2016, Electrical Engineering

Acousto-optic beam steering has been used over the years for a variety of applications [1, 2]. The ability to steer laser beams at high frequencies (tens of MHz to a few GHz) electronically with high angular resolution (given Bragg angles in the mrad range) makes the Bragg cell an ideal device for angular and spatial steering. Lasers are extensively used in many applications such as target detection [3, 4] as well as in ocean depth measurement [5]. In this research, we describe a simple sector-based angular scanning system intended to cover a large surface area in order to identify and spatially locate relatively small objects scattered over the terrain [6]. The scanning system is modeled as a planar surface on the horizontal (XY) plane, with an acousto-optic Bragg cell on board an unmanned aerial vehicle (UAV) operating in the XZ plane. The Bragg cell is excited by a chirped RF signal with frequency ramping from low-to-high or high to-low. As the scanning beam reflects off the horizontal surface, a detector placed on the UAV picks up the reflected wave (shown to be effective over the scan range), and thereby evaluates the refractive index of the material at the location on the basis of the corresponding Fresnel reflection coefficient [7]. If the surface is, say, primarily sea water, then the detection is considered “negative” unless a material different from sea water is detected. Following each horizontal scan (about 374.15 m) within a sector, the return path is a blank. The Bragg cell, mounted on a stepper motor, is then rotated in the horizontal plane by a small angle, and the second scan run is carried out from the rotated position. Following this process with only L-to-R or R-to-L active scans and interleaving blanks, a “unit” circular sector is scanned with physical dimensions approximately 374.15 m × 300 m. Any “positive” refractive index returned by the sensor is stored in the system in terms of the spatial coordinates of the scanned point. Since the unit s (open full item for complete abstract)

Doctor of Philosophy (Ph.D.), University of Dayton, 2016, Engineering

Atmospheric turbulence as an agency affecting the propagation of electromagnetic (EM) waves in different regions of the earth relative to the ground plane has been studied extensively over the past several decades. Mathematical models describing turbulence itself relative to EM waves have been developed by a variety of investigators in the last 50 or more years. It turns out that the majority of these models are essentially in the spatial domain, involving transverse spatial coordinates and their spatial frequency counterparts in the spectral domain. Most turbulence models start out by assuming a random dependence of the medium permittivity on the turbulence. This leads to a random model describing what is commonly referred to as the refractive index power density spectrum. It is well known that propagation through standard atmospheric turbulence creates ripples, random distortions, phase variations and also for monochromatic cases scintillations in the recovered signals. One idea that was proposed to the investigators of this research was that perhaps pre-packaging the EM signal inside a trackable chaos waveform might offer some measure of shielding for the signal even as the overall EM wave passes through turbulence. With this objective in mind, this work began by first establishing standard numerical simulations of EM propagation through homogeneous regions upon passage through a variety of apertures. This standard application involved the use of the Fresnel-Kirchhoff diffraction integral implemented in two ways: (a) as a direct propagation from an object to an image plane, and (b) segmented propagation over uniform incremental layers of the medium in the longitudinal direction. The latter approach was put into place in anticipation of the later introduction of a turbulent layer in the system. Following successful implementation of this technique, turbulence was inserted once again in two different ways: (a) assuming a relatively narrow region of turbulenc (open full item for complete abstract)

Master of Science, University of Akron, 2015, Electrical Engineering

Linear and rectangular aperture arrays combined with multidimensional (MD) signal processing techniques enable directional enhancement of plane waves by creating highly directional radio frequency (RF) beams. Applications of such space-time filtering (beamforming) techniques can be found in areas such as radar, mobile communication, cognitive radio and radio astronomy. Main challenges in existing beamforming systems include high computational and hardware complexity, low operational bandwidth, and limited spatial selectivity. In this thesis, we employ the network resonant infinite impulse response (IIR) digital beam filter towards the performance enhancement of the existing beamforming systems and its related applications in terms of hardware complexity, spatial selectivity and operational bandwidth. Inherent properties of IIR beam filters, such as \emph{low complexity, higher operational bandwidth, multiple input multiple output (MIMO) nature, recursive structure and electronically steerablity} lead to improve directivity properties of the conventional beamformers and enable less complex directional enhancement for wideband applications. Low complexity directional spectrum sensing and feature extraction approach is proposed by combining network resonant beam filters with cyclostationary feature detectors. Spatial selectivity of the conventional beamformer is significantly enhanced by employing a MD MIMO beam filter as a pre-filter to the existing system. Furthermore, an electronically steerable transmit-beamformer based on space-time network resonant IIR discrete systems is proposed for wideband directed energy applications.

Master of Science in Engineering, University of Akron, 2014, Electrical Engineering

Beam-enhanced digital aperture arrays employ two-dimensional (2-D) infinite impulse response (IIR) beam filters as a pre-processing stage to existing phased/timed-array beamforming to obtain isignificantly lower side-lobe levels (SLLs) for the same array size. We propose end-to-end digital hardware architectures for beam-enhanced linear aperture arrays including four sub-systems: 2-D IIR pre-filtering; real-time beam steering via fast computation of filter coefficient; compensation for non-linear phase; and conventional phased/timed-array beamforming. Speed-optimized systolic array (SA) digital architectures are proposed for 1st and 2nd order 2-D IIR pre-filtering, including fast computation of filter coefficients to enable real-time beam steering at nano-second speeds. The inherent non-linear phase of 2-D IIR pre-filter is compensated via fast Fourier transform (FFT)-based phase rotations. Digital designs are implemented on Xilinx Virtex-6 XC6VLX240T fiield-programmable gate array (FPGA) platform and tested using on-chip hardware co-simulation (HCS). For 64 antennas, with binary phase shift keying (BPSK) modulation, the beam-enhanced digital aperture array provides better than 10 dB in bit error rate (BER) vs. signal- to-interference ratio (SIR) performance compared to conventional phased/timed array beamforming.

Master of Science (M.S.), University of Dayton, 2014, Electrical Engineering

An analytic examination of 3-D holography under a recording geometry was carried out earlier in which 2-D spatial Laplace transforms were introduced in order to develop transfer functions for the scattered outputs under readout [1]. Thereby, the resulting reconstructed output was obtained in the 2-D Laplace domain whence the spatial information would be found only by performing a 2-D Laplace inversion. Laplace inversion in 2-D was attempted by testing a prototype function for which the analytic result was known using two known inversion algorithms via the Brancik and the Abate [2]. The results indicated notable differences in the 3-D plots between the algorithms and the analytic result, and hence were somewhat inconclusive. In this research, we take a close look at the Brancik algorithm in order to understand better the implications of the choices of key parameters such as the real and imaginary parts of the Bromwich contour and the grids sizes of the summation operations [3]. To assess the inversion findings, three prototype test cases are considered for which the analytic solutions are known. For specific choices of the algorithm parameters, optimal values are determined that would minimize errors in general. It is found that even though errors accumulate near the edges of the grid, overall reasonably accurate inversions are possible to obtain with optimal parameter choices that are verifiable via cross-sectional views. For a holographic problem, a 90-deg geometry recording model is established to derive two important coupled equations [4]. The optimum parameters are used to find the output field profiles under readout for a uniform plane wave, a point source wave and a Gaussian profile input. To understand the results better, a convolutional approach and a holistic approach are compared. Further work may include recording and reconstructing a dynamic object wave whose wave representations are more complicated. Also, the observed “right shift” phenomeno (open full item for complete abstract)

MS, University of Cincinnati, 2014, Engineering and Applied Science: Civil Engineering

Coupled core wall systems with steel coupling beams are effective seismic force resisting systems to resist structural collapse. A typical coupling beam shear wall system would dissipate energy through the formation of plastic hinges at the coupling beam-wall interface. These plastic hinges would damage the coupling beam, requiring an infeasible and uneconomical repair involving the replacement of the beam embedded in the concrete wall pier. However, research at the University of Cincinnati has introduced a weak-link section (the fuse) at the mid-span of the coupling beam that will dissipate energy through shear yielding, leading to the development and modification of the steel fuse coupling beams. This would allow the plasticity at the face of the wall to be shifted to the mid-span of the coupling beam, requiring a feasible and economical repair involving only the replacement of the fuse at mid-span.

Master of Science in Engineering (MSEgr), Wright State University, 2012, Biomedical Engineering

In computed tomography (CT) systems, many different artifacts may be present in the reconstructed image. These artifacts can greatly reduce image quality. For our laboratory prototype CT system, a fan-beam/cone-beam focal high-resolution computed tomography (fHRCT) scanner, the major artifacts that affect image quality are distortions due to errors in the reconstruction algorithm's geometric parameters, ring artifacts caused by uncalibrated detectors, cupping and streaking created by beam hardening, and patient-based motion artifacts. Optimization of the system was required to reduce the effects of the first three artifact types, and an algorithm for correction of translational motion was developed for the last. System optimization of the system occurred in three parts. First, a multi-step process was developed to determine the geometric parameters of the scanner. The ability of the source-detector gantry to translate allowed a precise method to be created for calculating these parameters. Second, a general flat-field correction was used to linearize the detectors and reduce the ring artifacts. Lastly, beam hardening artifacts were decreased by a preprocessing technique. This technique assumes linear proportionality between the thickness of the calibration material, aluminum, and the experimental measurement of ln(No/N), where No is the total number of photons entering the material and N is the number of photons exiting the material. In addition to system optimization to minimize artifacts, an algorithm for correction of translational motion was developed and implemented. In this method, the integral mass and center of mass at each projection angle was seen to follow a sinusoidal or sinusoidal-like curve. Fits were used on the motion-encoded sinograms to determine both of these curves and, consequently, the amount and direction of motion that occurred. Each projection was individually adjusted to compensate for this motion by widening or narrowing the projection bas (open full item for complete abstract)

Master of Science in Engineering (MSEgr), Wright State University, 2011, Electrical Engineering

Typical radar systems are limited to energy distribution characteristics that are range independent. However, operators are generally interested in obtaining information at particular ranges and discarding elsewhere. It seems appropriate then to attempt to put energy solely at the range(s) of interest, thus minimizing exposure to clutter, jammers and other range-dependent interferences sources. The frequency diverse array (FDA) can provide a mechanism to achieve range-dependent beamforming and the spatial energy distribution properties are investigated on transmit and receive for different architectures herein. While simplified FDA receive architectures have been explored, they exclude the return signals from transmitters that are not frequency matched. This practice neglects practical consideration in receiver implementation and has motivated research to formulate a design that includes all frequencies. We present several receiver architectures for a uniform linear FDA, and compare the processing chain and spatial patterns in order to formulate an argument for the most efficient design to maximize gain on target. It may also be desirable to beamsteer in higher dimensionalities than a linear array affords, thus, the transmit and receive concept is extended to a generic planar array. This new architecture allows 3-D beamsteering in angle and range while maintaining practicality. The spatial patterns that arise are extremely unique and afford the radar designer an additional degree of freedom to develop operational strategy. The ability to simultaneously acquire, track, image and protect assets is a requirement of future fielded systems. The FDA architecture intrinsically covers multiple diversity domains and, therefore, naturally lends it self to a multi-mission, multi-mode adar scheme. A multiple beam technique that uses coding is suggested to advance this notion.

PhD, University of Cincinnati, 2001, Engineering : Electrical Engineering

Ga + focused ion beam (FIB) micromachining was utilized on GaN for the fabrication of photonic devices, such as channel waveguides, laser facets, reflectors, etc. FIB micromachining can provide several advantages on device fabrication: maskless and resistless process, local modification of the process conditions, and smooth surface on desired features. GaN and related materials are of great success for visible and UV optical devices. However, some fabrication issues are still remaining to overcome on sample preparation and processing. In particular, high reflectivity mirror facets is hard to obtain by conventional processing procedures due to the large misalignment between sapphire and GaN-based materials. Therefore, it is important to develop a simple and efficient processing technique. The main objective of this work is to combine dry etching techniques to manufacture the ridge waveguides and FIB micromaching to fabricate small period Distributed Bragg Reflector (DBR) mirrors. The milling selectivity of GaN to the grown substrates such as sapphire, SiC and Si (111) is 3x better. By introducing I 2 gas, the etching rates of FIB micromachining with gas-assisted etching are enhanced 6 - 8x faster than that of FIB micromachining alone on GaN. To fabricate GaN waveguides, the optimized conditions of reactive ion etching are 20 sccm of Cl 2 , 400 Watts of RIE power as well as the chamber pressure of 5 mTorr. Rapid thermal annealing is to recover the ion damages created in the processing of dry etching and FIB micromachining. The modeling of Jone's matrix theory is to provide the information of reflectivity for the structure of Bragg gratings. The effect of gratings is obtained from loss measurement to measure the propagation of laser light sources in the SiON ridge waveguides. However, the width shifting of gratings generated by FIB micromachining causes the reflectivity shifting in the loss measurements. The AFM scanning and modeling confirm that phenomena due to the p (open full item for complete abstract)

MS, University of Cincinnati, 2008, Medicine : Radiology-Radiological Sciences (Medical Physics)

The presence of image "blooming" artifacts, in particular with respect to highly calcifiedplaques, has been a major impediment to the implementation of Multi-detector Computed Tomography (MD-CT) as an alternative to standard angiography in routine clinical practice. A beam hardening phantom system was developed to determine the dependence of blooming with respect to measured density in Hounsfield Units (HU), of 5mm diameter plaques. Custom software was developed to provide reproducible objective measurements of plaque size. Plaque diameter was measured using a series of axially distributed profiles centered on the object. Reconstruction blur was shown to be a significant, density dependent contributor to standard clinical blooming measurements. Beam hardening was shown to not affect measurements of sample diameter in a blur corrected study. Furthermore, two additional phantom designs have been proposed and evaluated for the future study of partial volume and cone beam affects on blooming.