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- All Subjects: engineering
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- Creators: Rogers, Bradley
- Creators: Salerno, Jessica
Description
The object of this study was a 26 year old residential Photovoltaic (PV) monocrystalline silicon (c-Si) power plant, called Solar One, built by developer John F. Long in Phoenix, Arizona (a hot-dry field condition). The task for Arizona State University Photovoltaic Reliability Laboratory (ASU-PRL) graduate students was to evaluate the power plant through visual inspection, electrical performance, and infrared thermography. The purpose of this evaluation was to measure and understand the extent of degradation to the system along with the identification of the failure modes in this hot-dry climatic condition. This 4000 module bipolar system was originally installed with a 200 kW DC output of PV array (17 degree fixed tilt) and an AC output of 175 kVA. The system was shown to degrade approximately at a rate of 2.3% per year with no apparent potential induced degradation (PID) effect. The power plant is made of two arrays, the north array and the south array. Due to a limited time frame to execute this large project, this work was performed by two masters students (Jonathan Belmont and Kolapo Olakonu) and the test results are presented in two masters theses. This thesis presents the results obtained on the north array and the other thesis presents the results obtained on the south array. The resulting study showed that PV module design, array configuration, vandalism, installation methods and Arizona environmental conditions have had an effect on this system's longevity and reliability. Ultimately, encapsulation browning, higher series resistance (potentially due to solder bond fatigue) and non-cell interconnect ribbon breakages outside the modules were determined to be the primary causes for the power loss.
ContributorsBelmont, Jonathan (Author) / Tamizhmani, Govindasamy (Thesis advisor) / Henderson, Mark (Committee member) / Rogers, Bradley (Committee member) / Arizona State University (Publisher)
Created2013
Description
While the piezoelectric effect has been around for some time, it has only recently caught interest as a potential sustainable energy harvesting device. Piezoelectric energy harvesting has been developed for shoes and panels, but has yet to be integrated into a marketable bicycle tire. For this thesis, the development and feasibility of a piezoelectric tire was done. This includes the development of a circuit that incorporates piezoceramic elements, energy harvesting circuitry, and an energy storage device. A single phase circuit was designed using an ac-dc diode rectifier. An electrolytic capacitor was used as the energy storage device. A financial feasibility was also done to determine targets for manufacturing cost and sales price. These models take into account market trends for high performance tires, economies of scale, and the possibility of government subsidies. This research will help understand the potential for the marketability of a piezoelectric energy harvesting tire that can create electricity for remote use. This study found that there are many obstacles that must be addressed before a piezoelectric tire can be marketed to the general public. The power output of this device is miniscule compared to an alkaline battery. In order for this device to approach the power output of an alkaline battery the weight of the device would also become an issue. Additionally this device is very costly compared to the average bicycle tire. Lastly, this device is extreme fragile and easily broken. In order for this device to become marketable the issues of power output, cost, weight, and durability must all be successfully overcome.
ContributorsMalotte, Christopher (Author) / Madakannan, Arunachalanadar (Thesis advisor) / Srinivasan, Devarajan (Committee member) / Rogers, Bradley (Committee member) / Arizona State University (Publisher)
Created2012
Description
Potential induced degradation (PID) due to high system voltages is one of the major degradation mechanisms in photovoltaic (PV) modules, adversely affecting their performance due to the combined effects of the following factors: system voltage, superstrate/glass surface conductivity, encapsulant conductivity, silicon nitride anti-reflection coating property and interface property (glass/encapsulant; encapsulant/cell; encapsulant/backsheet). Previous studies carried out at ASU's Photovoltaic Reliability Laboratory (ASU-PRL) showed that only negative voltage bias (positive grounded systems) adversely affects the performance of commonly available crystalline silicon modules. In previous studies, the surface conductivity of the glass surface was obtained using either conductive carbon layer extending from the glass surface to the frame or humidity inside an environmental chamber. This thesis investigates the influence of glass surface conductivity disruption on PV modules. In this study, conductive carbon was applied only on the module's glass surface without extending to the frame and the surface conductivity was disrupted (no carbon layer) at 2cm distance from the periphery of frame inner edges. This study was carried out under dry heat at two different temperatures (60 °C and 85 °C) and three different negative bias voltages (-300V, -400V, and -600V). To replicate closeness to the field conditions, half of the selected modules were pre-stressed under damp heat for 1000 hours (DH 1000) and the remaining half under 200 hours of thermal cycling (TC 200). When the surface continuity was disrupted by maintaining a 2 cm gap from the frame to the edge of the conductive layer, as demonstrated in this study, the degradation was found to be absent or negligibly small even after 35 hours of negative bias at elevated temperatures. This preliminary study appears to indicate that the modules could become immune to PID losses if the continuity of the glass surface conductivity is disrupted at the inside boundary of the frame. The surface conductivity of the glass, due to water layer formation in a humid condition, close to the frame could be disrupted just by applying a water repelling (hydrophobic) but high transmittance surface coating (such as Teflon) or modifying the frame/glass edges with water repellent properties.
ContributorsTatapudi, Sai Ravi Vasista (Author) / Tamizhmani, Govindasamy (Thesis advisor) / Srinivasan, Devarajan (Committee member) / Rogers, Bradley (Committee member) / Arizona State University (Publisher)
Created2012
Description
While acceptance towards same-sex marriage is gradually increasing, same-sex marriage is banned in many states within the United States. Laws that prohibit same-sex couples from marrying have been shown to increase feelings of depression, exclusion, and stigma for same-sex attracted individuals. The intention of this study was to explore the effect both pro- and anti-same-sex marriage advertisements have on heterosexual individuals' implicit attitudes towards same-sex couples. It was predicted that exposure to anti-same-sex advertisements would lead to viewing same-sex couples as more unpleasant and heterosexual couples as being more pleasant. However, heterosexual participants who viewed anti-same-sex marriage ads were more likely to rate heterosexual couples as being unpleasant and same-sex couples as pleasant. It is theorized that viewing anti-same-sex marriage advertisements led heterosexual individuals to report heterosexual stimuli as being more unpleasant compared to same-sex stimuli as a form of defensive processing.
ContributorsWalsh, Theodora Michelle (Author) / Newman, Matt (Thesis advisor) / Hall, Deborah (Committee member) / Salerno, Jessica (Committee member) / Arizona State University (Publisher)
Created2013
Description
Bully victimization has been associated with blunted cardiovascular responses to stress as well as elevated responses to stress. The difference between these altered physiological responses to stress is largely unknown. This study explored several possible moderators to the relationship between chronic stress and future cardiac output (an indicator of increased stress) in response to future stressors. These moderators include the difference between social and physical stressors and individual levels of loneliness. Participants were administered measures of loneliness and victimization history, and led to anticipate either a "social" (recorded speech) or "non-social" (pain tolerance test ) stressor, neither of which occurred. EKG and impedance cardiography were measured throughout the session. When anticipating both stressors, loneliness and victimization were associated with increased CO. A regression revealed a three-way interaction, with change in cardiac output depending on victimization history, loneliness, and condition in the physical stressor condition. Loneliness magnified the CO output levels of non-bullied individuals when facing a physical stressor. These results suggest that non- bullied participants high in loneliness are more stressed out when facing stressors, particularly stressors that are physically threatening in nature.
ContributorsHaneline, Magen (Author) / Newman, Matt (Thesis advisor) / Salerno, Jessica (Committee member) / Miller, Paul (Committee member) / Arizona State University (Publisher)
Created2013
Description
This report presents the effects and analysis of the effects of Pulsed-Gas Metal Arc Welding's (P-GMAW) on Lean Duplex stainless steel. Although the welding of Duplex and Super Duplex Stainless steels have been well documented in both the laboratory and construction industry, the use of Lean Duplex has not. The purpose for conducting this research is to ensure that the correct Ferrite-Austenite phase balance along with the correct welding procedures are used in the creation of reactor cores for new construction nuclear power generation stations. In this project the effects of Lincoln Electrics ER-2209 GMAW wire are studied. Suggestions and improvements to the welding process are then proposed in order to increase the weldability, strength, gas selection, and ferrite count. The weldability will be measured using X-Ray photography in order to determine if any inclusions, lack of fusion, or voids are found post welding, along with welder feedback. The ferritic point count method in accordance with ASTM A562-08, is employed so that the amount of ferrite and austenite can be calculated in the same manor that is currently being used in industry. These will then be correlated to the tensile strength and impact toughness in the heat-affected zone (HAZ) of the weld based on the ASTM A923 testing method.
ContributorsCarter, Roger (Author) / Rogers, Bradley (Thesis advisor) / Gintz, Jerry (Committee member) / Georgeou, Trian (Committee member) / Arizona State University (Publisher)
Created2012
Description
Previous studies exploring variability in sentencing decisions have consistently found gender differences, such that women receive lighter sentences than men. In the proposed study, I present a new framework for understanding gender differences in sentencing preferences, including circumstances under which no gender differences should emerge. The Affordance Management Approach suggests that our minds are attuned to both group- and individual-level threats and opportunities that others afford us. I conceptualize the sentencing difference between men and women as driven by perceived affordances that assist or hinder an individual in achieving certain fundamental goals. When faced with sanctioning an offender in our community, the offender's sex, the victim's age, and environmental variables such as the ratio of men to women may influence our decision-making, because these factors have affordance implications. Thus, I hypothesized that individuals will express differences in the sentencing of offenders who commit assault, and that these differences vary by offender sex, victim age, and sex-ratio. The results indicate that, as predicted, female offenders received lighter sentencing than men when the offender committed an assault against a same-sex adult, but received equally punitive sentences as men when the assault was committed against a child. In general, results do not support a consistent effect of sex ratio as a factor when making sentencing decisions. Although results do not fully support the current study's specific hypotheses, there remains much to be gained from applying an affordance management perspective to understanding variability in sentencing between the sexes.
ContributorsUzzanti, Charlene Ann (Author) / Neuberg, Steven (Thesis director) / Knight, George (Committee member) / Salerno, Jessica (Committee member) / Barrett, The Honors College (Contributor) / School of Criminology and Criminal Justice (Contributor) / Department of Psychology (Contributor)
Created2015-05
Description
Prior research has indicated an attractive-leniency bias for defendants in mock jury studies. However, in recent years there have been highly publicized trials of attractive women who also appear sexual, in which juror's judgements do not show support for the attractive-leniency bias. The opposite effect seems to be taking place. The present study is the first to test the Femme Fatale stereotype that seems to be producing harsher judgements of attractive and sexually appealing women who commit crime, and the interaction of the relationship to their victim. The present study conducted a 2 (Attractiveness) X 2 (Sexual Appearance) X 2 (Relationship) between subjects design. Researchers conducted an ANOVA on all variables. Results indicate that women who are perceived as more attractive and more sexual, are more likely to be found guilty of their crime.
ContributorsBernal, Kelsey Joann (Author) / Salerno, Jessica (Thesis director) / Neal, Tess (Committee member) / School of Social and Behavioral Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
Suction stabilized floats have been implemented into a variety of applications such as supporting wind turbines in off-shore wind farms and for stabilizing cargo ships. This thesis proposes an alternative use for the technology in creating a system of suction stabilized floats equipped with real time location modules to help first responders establish a localized coordinate system to assist in rescues. The floats create a stabilized platform for each anchor module due to the inverse slack tank effect established by the inner water chamber. The design of the float has also been proven to be stable in most cases of amplitudes and frequencies ranging from 0 to 100 except for when the frequency ranges from 23 to 60 Hz for almost all values of the amplitude. The modules in the system form a coordinate grid based off the anchors that can track the location of a tag module within the range of the system using ultra-wideband communications. This method of location identification allows responders to use the system in GPS denied environments. The system can be accessed through an Android app with Bluetooth communications in close ranges or through internet of things (IoT) using a module as a listener, a Raspberry Pi and an internet source. The system has proven to identify the location of the tag in moderate ranges with an approximate accuracy of the tag location being 15 cm.
ContributorsDye, Michaela (Author) / Redkar, Sangram (Thesis advisor) / Sugar, Thomas (Committee member) / Rogers, Bradley (Committee member) / Arizona State University (Publisher)
Created2020
Description
It has recently been argued that high-confidence eyewitness identifications are highly likely to be accurate regardless of the quality of viewing conditions experienced by the witness. However, new evidence suggests that evaluators of eyewitness identification evidence (e.g., jurors) do not trust highly confident eyewitnesses who experienced poor witnessing conditions. In fact, contextual information about poor witnessing conditions decreases evaluators’ belief of eyewitnesses to a greater extent for highly confident witnesses than for moderately confident witnesses. Why is the effect of witnessing-condition information greater for evaluations of high-confidence witnesses than for less confident witnesses? The current research tested the possibility that information about witnessing conditions influences evaluators’ perceptions of how well-calibrated a witness’s identification confidence is with the eyewitness’s accuracy. Using a paradigm adapted from the confidence calibration literature, I conducted an experiment to test this calibration account of the finding that witnessing condition information has a stronger effect on perceptions of highly confident witnesses than moderately confident witnesses. Although the results replicated the differential effects of witnessing condition context on perceptions of highly and moderately confident eyewitnesses, they failed to yield support for the confidence calibration hypothesis, potentially because the confidence calibration manipulation was ineffective. Directions for future research are discussed.
ContributorsLebensfeld, Taylor Cameron (Author) / Smalarz, Laura (Thesis advisor) / Salerno, Jessica (Committee member) / Arndorfer, Andrea (Committee member) / Arizona State University (Publisher)
Created2022