Matching Items (27)
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- All Subjects: engineering
- Creators: Goryll, Michael
Description
Within the last decade there has been remarkable interest in single-cell metabolic analysis as a key technology for understanding cellular heterogeneity, disease initiation, progression, and drug resistance. Technologies have been developed for oxygen consumption rate (OCR) measurements using various configurations of microfluidic devices. The technical challenges of current approaches include: (1) deposition of multiple sensors for multi-parameter metabolic measurements, e.g. oxygen, pH, etc.; (2) tedious and labor-intensive microwell array fabrication processes; (3) low yield of hermetic sealing between two rigid fused silica parts, even with a compliance layer of PDMS or Parylene-C. In this thesis, several improved microfabrication technologies are developed and demonstrated for analyzing multiple metabolic parameters from single cells, including (1) a modified "lid-on-top" configuration with a multiple sensor trapping (MST) lid which spatially confines multiple sensors to micro-pockets enclosed by lips for hermetic sealing of wells; (2) a multiple step photo-polymerization method for patterning three optical sensors (oxygen, pH and reference) on fused silica and on a polyethylene terephthalate (PET) surface; (3) a photo-polymerization method for patterning tri-color (oxygen, pH and reference) optical sensors on both fused silica and on the PET surface; (4) improved KMPR/SU-8 microfabrication protocols for fabricating microwell arrays that can withstand cell culture conditions. Implementation of these improved microfabrication methods should address the aforementioned challenges and provide a high throughput and multi-parameter single cell metabolic analysis platform.
ContributorsSong, Ganquan (Author) / Meldrum, Deirdre R (Thesis advisor) / Goryll, Michael (Committee member) / Wang, Hong (Committee member) / Tian, Yanqing (Committee member) / Arizona State University (Publisher)
Created2014
Description
High speed current-steering DACs with high linearity are needed in today's applications such as wired and wireless communications, instrumentation, radar, and other direct digital synthesis (DDS) applications. However, a trade-off exists between the speed and resolution of Nyquist rate current-steering DACs. As the resolution increases, more transistor area is required to meet matching requirements for optimal linearity and thus, the overall speed of the DAC is limited.
In this thesis work, a 12-bit current-steering DAC was designed with current sources scaled below the required matching size to decrease the area and increase the overall speed of the DAC. By scaling the current sources, however, errors due to random mismatch between current sources will arise and additional calibration hardware is necessary to ensure 12-bit linearity. This work presents how to implement a self-calibration DAC that works to fix amplitude errors while maintaining a lower overall area. Additionally, the DAC designed in this thesis investigates the implementation feasibility of a data-interleaved architecture. Data interleaving can increase the total bandwidth of the DACs by 2 with an increase in SQNR by an additional 3 dB.
The final results show that the calibration method can effectively improve the linearity of the DAC. The DAC is able to run up to 400 MSPS frequencies with a 75 dB SFDR performance and above 87 dB SFDR performance at update rates of 200 MSPS.
In this thesis work, a 12-bit current-steering DAC was designed with current sources scaled below the required matching size to decrease the area and increase the overall speed of the DAC. By scaling the current sources, however, errors due to random mismatch between current sources will arise and additional calibration hardware is necessary to ensure 12-bit linearity. This work presents how to implement a self-calibration DAC that works to fix amplitude errors while maintaining a lower overall area. Additionally, the DAC designed in this thesis investigates the implementation feasibility of a data-interleaved architecture. Data interleaving can increase the total bandwidth of the DACs by 2 with an increase in SQNR by an additional 3 dB.
The final results show that the calibration method can effectively improve the linearity of the DAC. The DAC is able to run up to 400 MSPS frequencies with a 75 dB SFDR performance and above 87 dB SFDR performance at update rates of 200 MSPS.
ContributorsJankunas, Benjamin (Author) / Bakkaloglu, Bertan (Thesis advisor) / Kitchen, Jennifer (Committee member) / Ozev, Sule (Committee member) / Arizona State University (Publisher)
Created2014
Description
Hydrogen sulfide (H2S) has been identified as a potential ingredient for grain boundary passivation of multicrystalline silicon. Sulfur is already established as a good surface passivation material for crystalline silicon (c-Si). Sulfur can be used both from solution and hydrogen sulfide gas. For multicrystalline silicon (mc-Si) solar cells, increasing efficiency is a major challenge because passivation of mc-Si wafers is more difficult due to its randomly orientated crystal grains and the principal source of recombination is contributed by the defects in the bulk of the wafer and surface.
In this work, a new technique for grain boundary passivation for multicrystalline silicon using hydrogen sulfide has been developed which is accompanied by a compatible Aluminum oxide (Al2O3) surface passivation. Minority carrier lifetime measurement of the passivated samples has been performed and the analysis shows that success has been achieved in terms of passivation and compared to already existing hydrogen passivation, hydrogen sulfide passivation is actually better. Also the surface passivation by Al2O3 helps to increase the lifetime even more after post-annealing and this helps to attain stability for the bulk passivated samples. Minority carrier lifetime is directly related to the internal quantum efficiency of solar cells. Incorporation of this technique in making mc-Si solar cells is supposed to result in higher efficiency cells. Additional research is required in this field for the use of this technique in commercial solar cells.
In this work, a new technique for grain boundary passivation for multicrystalline silicon using hydrogen sulfide has been developed which is accompanied by a compatible Aluminum oxide (Al2O3) surface passivation. Minority carrier lifetime measurement of the passivated samples has been performed and the analysis shows that success has been achieved in terms of passivation and compared to already existing hydrogen passivation, hydrogen sulfide passivation is actually better. Also the surface passivation by Al2O3 helps to increase the lifetime even more after post-annealing and this helps to attain stability for the bulk passivated samples. Minority carrier lifetime is directly related to the internal quantum efficiency of solar cells. Incorporation of this technique in making mc-Si solar cells is supposed to result in higher efficiency cells. Additional research is required in this field for the use of this technique in commercial solar cells.
ContributorsSaha, Arunodoy, Ph.D (Author) / Tao, Meng (Thesis advisor) / Vasileska, Dragica (Committee member) / Goryll, Michael (Committee member) / Arizona State University (Publisher)
Created2014
Description
Pulse Density Modulation- (PDM-) based class-D amplifiers can reduce non-linearity and tonal content due to carrier signal in Pulse Width Modulation - (PWM-) based amplifiers. However, their low-voltage analog implementations also require a linear- loop filter and a quantizer. A PDM-based class-D audio amplifier using a frequency-domain quantization is presented in this paper. The digital-intensive frequency domain approach achieves high linearity under low-supply regimes. An analog comparator and a single-bit quantizer are replaced with a Current-Controlled Oscillator- (ICO-) based frequency discriminator. By using the ICO as a phase integrator, a third-order noise shaping is achieved using only two analog integrators. A single-loop, singlebit class-D audio amplifier is presented with an H-bridge switching power stage, which is designed and fabricated on a 0.18 um CMOS process, with 6 layers of metal achieving a total harmonic distortion plus noise (THD+N) of 0.065% and a peak power efficiency of 80% while driving a 4-ohms loudspeaker load. The amplifier can deliver the output power of 280 mW.
ContributorsLee, Junghan (Author) / Bakkaloglu, Bertan (Thesis advisor) / Kiaei, Sayfe (Committee member) / Ozev, Sule (Committee member) / Song, Hongjiang (Committee member) / Arizona State University (Publisher)
Created2011
Description
ABSTRACT To meet stringent market demands, manufacturers must produce Radio Frequency (RF) transceivers that provide wireless communication between electronic components used in consumer products at extremely low cost. Semiconductor manufacturers are in a steady race to increase integration levels through advanced system-on-chip (SoC) technology. The testing costs of these devices tend to increase with higher integration levels. As the integration levels increase and the devices get faster, the need for high-calibre low cost test equipment become highly dominant. However testing the overall system becomes harder and more expensive. Traditionally, the transceiver system is tested in two steps utilizing high-calibre RF instrumentation and mixed-signal testers, with separate measurement setups for transmitter and receiver paths. Impairments in the RF front-end, such as the I/Q gain and phase imbalance and nonlinearity, severely affect the performance of the device. The transceiver needs to be characterized in terms of these impairments in order to guarantee good performance and specification requirements. The motivation factor for this thesis is to come up with a low cost and computationally simple extraction technique of these impairments. In the proposed extraction technique, the mapping between transmitter input signals and receiver output signals are used to extract the impairment and nonlinearity parameters. This is done with the help of detailed mathematical modeling of the transceiver. While the overall behavior is nonlinear, both linear and nonlinear models to be used under different test setups are developed. A two step extraction technique has been proposed in this work. The extraction of system parameters is performed by using the mathematical model developed along with a genetic algorithm implemented in MATLAB. The technique yields good extraction results with reasonable error. It uses simple mathematical operation which makes the extraction fast and computationally simple when compared to other existing techniques such as traditional two step dedicated approach, Nonlinear Solver (NLS) approach, etc. It employs frequency domain analysis of low frequency input and output signals, over cumbersome time domain computations. Thus a test method, including detailed behavioral modeling of the transceiver, appropriate test signal design along with a simple algorithm for extraction is presented.
ContributorsSreenivassan, Aiswariya (Author) / Ozev, Sule (Thesis advisor) / Kiaei, Sayfe (Committee member) / Bakkaloglu, Bertan (Committee member) / Arizona State University (Publisher)
Created2011
Description
Biosensors aiming at detection of target analytes, such as proteins, microbes, virus, and toxins, are widely needed for various applications including detection of chemical and biological warfare (CBW) agents, biomedicine, environmental monitoring, and drug screening. Surface Plasmon Resonance (SPR), as a surface-sensitive analytical tool, can very sensitively respond to minute changes of refractive index occurring adjacent to a metal film, offering detection limits up to a few ppt (pg/mL). Through SPR, the process of protein adsorption may be monitored in real-time, and transduced into an SPR angle shift. This unique technique bypasses the time-consuming, labor-intensive labeling processes, such as radioisotope and fluorescence labeling. More importantly, the method avoids the modification of the biomarker’s characteristics and behaviors by labeling that often occurs in traditional biosensors. While many transducers, including SPR, offer high sensitivity, selectivity is determined by the bio-receptors. In traditional biosensors, the selectivity is provided by bio-receptors possessing highly specific binding affinity to capture target analytes, yet their use in biosensors are often limited by their relatively-weak binding affinity with analyte, non-specific adsorption, need for optimization conditions, low reproducibility, and difficulties integrating onto the surface of transducers. In order to circumvent the use of bio-receptors, the competitive adsorption of proteins, termed the Vroman effect, is utilized in this work. The Vroman effect was first reported by Vroman and Adams in 1969. The competitive adsorption targeted here occurs among different proteins competing to adsorb to a surface, when more than one type of protein is present. When lower-affinity proteins are adsorbed on the surface first, they can be displaced by higher-affinity proteins arriving at the surface at a later point in time. Moreover, only low-affinity proteins can be displaced by high-affinity proteins, typically possessing higher molecular weight, yet the reverse sequence does not occur. The SPR biosensor based on competitive adsorption is successfully demonstrated to detect fibrinogen and thyroglobulin (Tg) in undiluted human serum and copper ions in drinking water through the denatured albumin.
ContributorsWang, Ran (Author) / Chae, Junseok (Thesis advisor) / Bakkaloglu, Bertan (Committee member) / Tsow, Tsing (Committee member) / Goryll, Michael (Committee member) / Arizona State University (Publisher)
Created2015
Description
Total dose sensing systems (or radiation detection systems) have many applications,
ranging from survey monitors used to supervise the generated radioactive waste at
nuclear power plants to personal dosimeters which measure the radiation dose
accumulated in individuals. This dissertation work will present two different types of
novel devices developed at Arizona State University for total dose sensing applications.
The first detector technology is a mechanically flexible metal-chalcogenide glass (ChG)
based system which is fabricated on low cost substrates and are intended as disposable
total dose sensors. Compared to existing commercial technologies, these thin film
radiation sensors are simpler in form and function, and cheaper to produce and operate.
The sensors measure dose through resistance change and are suitable for applications
such as reactor dosimetry, radiation chemistry, and clinical dosimetry. They are ideal for
wearable devices due to the lightweight construction, inherent robustness to resist
breaking when mechanically stressed, and ability to attach to non-flat objects. Moreover,
their performance can be easily controlled by tuning design variables and changing
incorporated materials. The second detector technology is a wireless dosimeter intended
for remote total dose sensing. They are based on a capacitively loaded folded patch
antenna resonating in the range of 3 GHz to 8 GHz for which the load capacitance varies
as a function of total dose. The dosimeter does not need power to operate thus enabling
its use and implementation in the field without requiring a battery for its read-out. As a
result, the dosimeter is suitable for applications such as unattended detection systems
destined for covert monitoring of merchandise crossing borders, where nuclear material
tracking is a concern. The sensitive element can be any device exhibiting a known
variation of capacitance with total ionizing dose. The sensitivity of the dosimeter is
related to the capacitance variation of the radiation sensitive device as well as the high
frequency system used for reading. Both technologies come with the advantage that they
are easy to manufacture with reasonably low cost and sensing can be readily read-out.
ranging from survey monitors used to supervise the generated radioactive waste at
nuclear power plants to personal dosimeters which measure the radiation dose
accumulated in individuals. This dissertation work will present two different types of
novel devices developed at Arizona State University for total dose sensing applications.
The first detector technology is a mechanically flexible metal-chalcogenide glass (ChG)
based system which is fabricated on low cost substrates and are intended as disposable
total dose sensors. Compared to existing commercial technologies, these thin film
radiation sensors are simpler in form and function, and cheaper to produce and operate.
The sensors measure dose through resistance change and are suitable for applications
such as reactor dosimetry, radiation chemistry, and clinical dosimetry. They are ideal for
wearable devices due to the lightweight construction, inherent robustness to resist
breaking when mechanically stressed, and ability to attach to non-flat objects. Moreover,
their performance can be easily controlled by tuning design variables and changing
incorporated materials. The second detector technology is a wireless dosimeter intended
for remote total dose sensing. They are based on a capacitively loaded folded patch
antenna resonating in the range of 3 GHz to 8 GHz for which the load capacitance varies
as a function of total dose. The dosimeter does not need power to operate thus enabling
its use and implementation in the field without requiring a battery for its read-out. As a
result, the dosimeter is suitable for applications such as unattended detection systems
destined for covert monitoring of merchandise crossing borders, where nuclear material
tracking is a concern. The sensitive element can be any device exhibiting a known
variation of capacitance with total ionizing dose. The sensitivity of the dosimeter is
related to the capacitance variation of the radiation sensitive device as well as the high
frequency system used for reading. Both technologies come with the advantage that they
are easy to manufacture with reasonably low cost and sensing can be readily read-out.
ContributorsMahmud, Adnan, Ph.D (Author) / Barnaby, Hugh J. (Thesis advisor) / Kozicki, Michael N (Committee member) / Gonzalez-Velo, Yago (Committee member) / Goryll, Michael (Committee member) / Alford, Terry (Committee member) / Arizona State University (Publisher)
Created2017
Description
In this project, current-voltage (I-V) and Deep Level Transient Spectroscopy (DLTS) measurements are used to (a) characterize the electrical properties of Nb/p-type Si Schottky barriers, (b) identify the concentration and physical character of the electrically active defects present in the depletion region, and (c) use thermal processing to reduce the concentration or eliminate the defects. Barrier height determinations using temperature-dependent I-V measurements indicate that the barrier height decreases from 0.50 eV to 0.48 eV for anneals above 200 C. The electrically-active defect concentration measured using DLTS (deep level transient spectroscopy) drops markedly after anneals at 250 C.
A significant increase in leakage currents is almost always observed in near-ideal devices upon annealing. In contrast, non-ideal devices dominated by leakage currents annealed at 150 C to 250 C exhibit a significant decrease in such currents.
A significant increase in leakage currents is almost always observed in near-ideal devices upon annealing. In contrast, non-ideal devices dominated by leakage currents annealed at 150 C to 250 C exhibit a significant decrease in such currents.
ContributorsKrishna Murthy, Madhu (Author) / Newman, Nathan (Thesis advisor) / Goryll, Michael (Committee member) / Alford, Terry (Committee member) / Arizona State University (Publisher)
Created2018
Description
Over the past several decades, there has been a growing interest in the use of fluorescent probes in low-cost diagnostic devices for resource-limited environments. This dissertation details the design, development, and deployment of an inexpensive, multiplexed, and quantitative, fluorescence-based lateral flow immunoassay platform, in light of the specific constraints associated with resource-limited settings.
This effort grew out of the need to develop a highly sensitive, field-deployable platform to be used as a primary screening and early detection tool for serologic biomarkers for the high-risk human papillomavirus (hrHPV) infection. A hrHPV infection is a precursor for developing high-grade cervical intraepithelial neoplasia (CIN 2/3+). Early detection requires high sensitivity and a low limit-of-detection (LOD). To this end, the developed platform (DxArray) takes advantage of the specificity of immunoassays and the selectivity of fluorescence for early disease detection. The long term goal is to improve the quality of life for several hundred million women globally, at risk of being infected with hrHPV.
The developed platform uses fluorescent labels over the gold-standard colorimetric labels in a compact, high-sensitivity lateral flow assay configuration. It is also compatible with POC settings as it substitutes expensive and bulky light sources for LEDs, low-light CMOS cameras, and photomultiplier tubes for photodiodes, in a transillumination architecture, and eliminates the need for expensive focusing/transfer optics. The platform uses high-quality interference filters at less than $1 each, enabling a rugged and robust design suitable for field use.
The limit of detection (LOD) of the developed platform is within an order of magnitude of centralized laboratory diagnostic instruments. It enhances the LOD of absorbance or reflectometric and visual readout lateral flow assays by 2 - 3 orders of magnitude. This system could be applied toward any chemical or bioanalytical procedure that requires a high performance at low-cost.
The knowledge and techniques developed in this effort is relevant to the community of researchers and industry developers looking to deploy inexpensive, quantitative, and highly sensitive diagnostic devices to resource-limited settings.
This effort grew out of the need to develop a highly sensitive, field-deployable platform to be used as a primary screening and early detection tool for serologic biomarkers for the high-risk human papillomavirus (hrHPV) infection. A hrHPV infection is a precursor for developing high-grade cervical intraepithelial neoplasia (CIN 2/3+). Early detection requires high sensitivity and a low limit-of-detection (LOD). To this end, the developed platform (DxArray) takes advantage of the specificity of immunoassays and the selectivity of fluorescence for early disease detection. The long term goal is to improve the quality of life for several hundred million women globally, at risk of being infected with hrHPV.
The developed platform uses fluorescent labels over the gold-standard colorimetric labels in a compact, high-sensitivity lateral flow assay configuration. It is also compatible with POC settings as it substitutes expensive and bulky light sources for LEDs, low-light CMOS cameras, and photomultiplier tubes for photodiodes, in a transillumination architecture, and eliminates the need for expensive focusing/transfer optics. The platform uses high-quality interference filters at less than $1 each, enabling a rugged and robust design suitable for field use.
The limit of detection (LOD) of the developed platform is within an order of magnitude of centralized laboratory diagnostic instruments. It enhances the LOD of absorbance or reflectometric and visual readout lateral flow assays by 2 - 3 orders of magnitude. This system could be applied toward any chemical or bioanalytical procedure that requires a high performance at low-cost.
The knowledge and techniques developed in this effort is relevant to the community of researchers and industry developers looking to deploy inexpensive, quantitative, and highly sensitive diagnostic devices to resource-limited settings.
ContributorsObahiagbon, Uwadiae (Author) / Blain Christen, Jennifer M (Thesis advisor) / Anderson, Karen S (Committee member) / Goryll, Michael (Committee member) / Smith, Barbara S. (Committee member) / Arizona State University (Publisher)
Created2018
Description
Current technology does not allow for the full amount of power produced by solar arrays (PV) on spacecraft to be utilized. The arrays are designed with non-reconfigurable architectures and sent on fifteen to twenty year long missions. They cannot be changed once they are in space, so the arrays are designed for the end of life. Throughout their lifetime, solar arrays can degrade in power producing capabilities anywhere from 20% to 50%. Because there is such a drastic difference in the beginning and end of life power production, and because they cannot be reconfigured, a new design has been found necessary in order to increase power production. Reconfiguration allows the solar arrays to achieve maximum power producing capabilities at both the beginning and end of their lives. With the potential to increase power production by 50%, the reconfiguration design consists of a switching network to be able to utilize any combination of cells. The design for reconfiguration must meet the power requirements of the solar array. This thesis will explore different designs for reconfiguration, as well as possible switches for implementation. It will also review other methods to increase power production, as well as discuss future work in this field.
ContributorsJohnson, Everett Hope (Author) / Kitchen, Jennifer (Thesis director) / Ozev, Sule (Committee member) / School of International Letters and Cultures (Contributor) / Electrical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05