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- Genre: Masters Thesis
Description
The slider-crank mechanism is popularly used in internal combustion engines to convert the reciprocating motion of the piston into a rotary motion. This research discusses an alternate mechanism proposed by the Wiseman Technology Inc. which involves replacing the crankshaft with a hypocycloid gear assembly. The unique hypocycloid gear arrangement allows the piston and the connecting rod to move in a straight line, creating a perfect sinusoidal motion. To analyze the performance advantages of the Wiseman mechanism, engine simulation software was used. The Wiseman engine with the hypocycloid piston motion was modeled in the software and the engine's simulated output results were compared to those with a conventional engine of the same size. The software was also used to analyze the multi-fuel capabilities of the Wiseman engine using a contra piston. The engine's performance was studied while operating on diesel, ethanol and gasoline fuel. Further, a scaling analysis on the future Wiseman engine prototypes was carried out to understand how the performance of the engine is affected by increasing the output power and cylinder displacement. It was found that the existing Wiseman engine produced about 7% less power at peak speeds compared to the slider-crank engine of the same size. It also produced lower torque and was about 6% less fuel efficient than the slider-crank engine. These results were concurrent with the dynamometer tests performed in the past. The 4 stroke diesel variant of the same Wiseman engine performed better than the 2 stroke gasoline version as well as the slider-crank engine in all aspects. The Wiseman engine using contra piston showed poor fuel efficiency while operating on E85 fuel. But it produced higher torque and about 1.4% more power than while running on gasoline. While analyzing the effects of the engine size on the Wiseman prototypes, it was found that the engines performed better in terms of power, torque, fuel efficiency and cylinder BMEP as their displacements increased. The 30 horsepower (HP) prototype, while operating on E85, produced the most optimum results in all aspects and the diesel variant of the same engine proved to be the most fuel efficient.
ContributorsRay, Priyesh (Author) / Redkar, Sangram (Thesis advisor) / Mayyas, Abdel Ra'Ouf (Committee member) / Meitz, Robert (Committee member) / Arizona State University (Publisher)
Created2014
Description
Creative design lies at the intersection of novelty and technical feasibility. These objectives can be achieved through cycles of divergence (idea generation) and convergence (idea evaluation) in conceptual design. The focus of this thesis is on the latter aspect. The evaluation may involve any aspect of technical feasibility and may be desired at component, sub-system or full system level. Two issues that are considered in this work are: 1. Information about design ideas is incomplete, informal and sketchy 2. Designers often work at multiple levels; different aspects or subsystems may be at different levels of abstraction Thus, high fidelity analysis and simulation tools are not appropriate for this purpose. This thesis looks at the requirements for a simulation tool and how it could facilitate concept evaluation. The specific tasks reported in this thesis are: 1. The typical types of information available after an ideation session 2. The typical types of technical evaluations done in early stages 3. How to conduct low fidelity design evaluation given a well-defined feasibility question A computational tool for supporting idea evaluation was designed and implemented. It was assumed that the results of the ideation session are represented as a morphological chart and each entry is expressed as some combination of a sketch, text and references to physical effects and machine components. Approximately 110 physical effects were identified and represented in terms of algebraic equations, physical variables and a textual description. A common ontology of physical variables was created so that physical effects could be networked together when variables are shared. This allows users to synthesize complex behaviors from simple ones, without assuming any solution sequence. A library of 16 machine elements was also created and users were given instructions about incorporating them. To support quick analysis, differential equations are transformed to algebraic equations by replacing differential terms with steady state differences), only steady state behavior is considered and interval arithmetic was used for modeling. The tool implementation is done by MATLAB; and a number of case studies are also done to show how the tool works. textual description. A common ontology of physical variables was created so that physical effects could be networked together when variables are shared. This allows users to synthesize complex behaviors from simple ones, without assuming any solution sequence. A library of 15 machine elements was also created and users were given instructions about incorporating them. To support quick analysis, differential equations are transformed to algebraic equations by replacing differential terms with steady state differences), only steady state behavior is considered and interval arithmetic was used for modeling. The tool implementation is done by MATLAB; and a number of case studies are also done to show how the tool works.
ContributorsKhorshidi, Maryam (Author) / Shah, Jami J. (Thesis advisor) / Wu, Teresa (Committee member) / Gel, Esma (Committee member) / Arizona State University (Publisher)
Created2014
Description
Although recent studies have report that many stressors and strains (i.e., financial, educational and psychological) arise from being an adolescent mother, whether adolescent motherhood influences delinquency remains an unanswered empirical question. Using data from a nationally representative sample of adolescents (National Longitudinal Study of Adolescent Health), the current study examines the relationship between motherhood, depression, and delinquency (N = 676). The sample is comprised of solely females between ages 13 and 21-years-old. The female subjects were categorized either as an adolescent mothers, non-mother adolescents, or adult mothers. This study tests the following hypotheses: (1) adolescent mothers are prone to involvement in delinquent behavior; and, (2) adolescent mothers who experience depression are at greater risk of delinquent behavior. The results indicate that there is a decrease in delinquency among adolescent mothers who do not experience depression. However, there is an increase in delinquency among adolescent mothers who experience depression.
ContributorsWalker, D'Andre (Author) / Holtfreter, Kristy (Thesis advisor) / Reisig, Micheal (Thesis advisor) / Burt, Callie (Committee member) / Arizona State University (Publisher)
Created2014
Description
This thesis contains the applications of the ASU mathematical model (Tolerance Maps, T-Maps) to the construction of T-Maps for patterns of line profiles. Previously, Tolerance Maps were developed for patterns of features such as holes, pins, slots and tabs to control their position. The T-Maps that are developed in this thesis are fully compatible with the ASME Y14.5 Standard. A pattern of square profiles, both linear and 2D, is used throughout this thesis to illustrate the idea of constructing the T-Maps for line profiles. The Standard defines two ways of tolerancing a pattern of profiles - Composite Tolerancing and Multiple Single Segment Tolerancing. Further, in the composite tolerancing scheme, there are two different ways to control the entire pattern - repeating a single datum or two datums in the secondary datum reference frame. T-Maps are constructed for all the different specifications. The Standard also describes a way to control the coplanarity of discontinuous surfaces using a profile tolerance and T-Maps have been developed. Since verification of manufactured parts relative to the tolerance specifications is crucial, a least squares fit approach, which was developed earlier for line profiles, has been extended to patterns of line profiles. For a pattern, two tolerances are specified, and the manufactured profile needs to lie within the tolerance zones established by both of these tolerances. An i-Map representation of the manufactured variation, located within the T-Map is also presented in this thesis.
ContributorsRao, Shyam Subramanya (Author) / Davidson, Joseph K. (Thesis advisor) / Arizona State University (Publisher)
Created2014
Description
Conformance of a manufactured feature to the applied geometric tolerances is done by analyzing the point cloud that is measured on the feature. To that end, a geometric feature is fitted to the point cloud and the results are assessed to see whether the fitted feature lies within the specified tolerance limits or not. Coordinate Measuring Machines (CMMs) use feature fitting algorithms that incorporate least square estimates as a basis for obtaining minimum, maximum, and zone fits. However, a comprehensive set of algorithms addressing the fitting procedure (all datums, targets) for every tolerance class is not available. Therefore, a Library of algorithms is developed to aid the process of feature fitting, and tolerance verification. This paper addresses linear, planar, circular, and cylindrical features only. This set of algorithms described conforms to the international Standards for GD&T.; In order to reduce the number of points to be analyzed, and to identify the possible candidate points for linear, circular and planar features, 2D and 3D convex hulls are used. For minimum, maximum, and Chebyshev cylinders, geometric search algorithms are used. Algorithms are divided into three major categories: least square, unconstrained, and constrained fits. Primary datums require one sided unconstrained fits for their verification. Secondary datums require one sided constrained fits for their verification. For size and other tolerance verifications, we require both unconstrained and constrained fits
ContributorsMohan, Prashant (Author) / Shah, Jami (Thesis advisor) / Davidson, Joseph K. (Committee member) / Farin, Gerald (Committee member) / Arizona State University (Publisher)
Created2014
Description
Interest in health and wellness has significantly increased in today's society. Living a healthy and active lifestyle is suggested to promote overall physical and psychological well-being. This study explored the effects of wearing a Fitbit Zip activity monitor and the impact of expressing mindfulness on levels of physical activity. It was predicted that expressing mindfulness, as measured by the use of present-tense language during the daily emotional writing task, would moderate the relationship between wearing a Fitbit Zip activity monitor and change in physical activity. Specifically, it was hypothesized daily monitoring would only lead to increased activity among those higher in mindful language. Over the course of five days, participants were asked to wear a Fitbit Zip and to complete a daily questionnaire and writing task at the end of each evening. On the last day of the study, participants completed a follow-up assessment, which suggested that the combination of wearing a Fitbit Zip activity monitor and expressing more mindfulness throughout the week increased levels of physical activity. An important issue for future research is to conduct this study for a longer period of time in order to get more variability in the data. However, despite the limitations of the design, these findings suggest that activity monitoring may be a promising way to promote healthy lifestyle change.
ContributorsTarachiu, Viorela (Author) / Newman, Matt L. (Thesis advisor) / Hall, Deborah (Committee member) / Salerno, Jessica (Committee member) / Arizona State University (Publisher)
Created2014
Description
ABSTRACT Research studies have demonstrated that stereotypes can elicit a priming response. An experiment was conducted to test the effects of priming elderly and young stereotypes on driving behavior. Participants drove in a driving simulator while navigating through two driving routes. Participants were guided by a neutral voice similar to "Siri" that informed them where to turn. Each route primed the participants with names that were deemed "old" or "young" as determined by a survey. The experiment yielded slower driving speeds in the elderly condition than in the young consistent with previous research regarding elderly stereotypes (Bargh et al, 1996; Branaghan and Gray, 2010; Taylor, 2010; Foster, 2012). These findings extend research on priming and behaviors elicited by participants in a simulated driving environment.
ContributorsThew, Lisa (Author) / Branaghan, Russell (Thesis advisor) / Song, Hyunjin (Committee member) / Kuzel, Michael (Committee member) / Arizona State University (Publisher)
Created2014
Description
Life History Theory suggests that, in order to maximize reproductive fitness, individuals make trade-offs between allocating resources to mating and parenting. These trade-offs are influenced by an individual's sex, life history strategy, and environment. Here, I explored the usefulness of a Life History Theory framework for understanding endorsement of child support laws. This study experimentally manipulated sex ratio, and gathered information about participants' endorsement of child support, sexual restrictedness, and mate value. As predicted, women endorsed child support more than men, whereas men favored greater restriction of child support in the form of required paternity testing. However, in general, results do not support an effect of sex ratio, sexual restrictedness, or mate value on endorsement of child support. Results suggest sensitivity to exploitation in a male-biased sex ratio, reflected by an increase in men's endorsement of paternity testing requirements under a male-biased sex ratio prime. Women, on the other hand, report especially unfavorable beliefs toward paternity testing in a male-biased sex ratio. Although results of the current study are mixed, there remains much to be gained from applying an evolutionary perspective to understanding variability in endorsement of child support.
ContributorsWilliams, Keelah (Author) / Neuberg, Steven L. (Thesis advisor) / Saks, Michael (Committee member) / Kenrick, Douglas (Committee member) / Ellman, Ira (Committee member) / Arizona State University (Publisher)
Created2013
Description
The present study examined the association of pain intensity and goal progress in a community sample of 132 adults with chronic pain who participated in a 21 day diary study. Multilevel modeling was employed to investigate the effect of morning pain intensity on evening goal progress as mediated by pain's interference with afternoon goal pursuit. Moderation effects of pain acceptance and pain catastrophizing on the associations between pain and interference with both work and lifestyle goal pursuit were also tested. The results showed that the relationship between morning pain and pain's interference with work goal pursuit in the afternoon was significantly moderated by a pain acceptance. In addition, it was found that the mediated effect differed across levels of pain acceptance; that is: (1) there was a significant mediation effect when pain acceptance was at its mean and one standard deviation below the mean; but (2) there was no mediation effect when pain acceptance was one standard deviation above the mean. It appears that high pain acceptance significantly attenuates the power of nociception in disrupting one's work goal pursuit. However, in the lifestyle goal model, none of the moderators were significant nor was there a significant association between pain interference with goal pursuit and goal progress. Only morning pain intensity significantly predicted afternoon interference with lifestyle goal pursuit. Further interpretation of the present findings and potential explanations of those inconsistencies are elaborated on discussion. Limitations and the clinical implication of the current study were considered, along with suggestions for future studies.
ContributorsMun, Chung Jung (Author) / Karoly, Paul (Thesis advisor) / Okun, Morris A. (Committee member) / Enders, Craig K. (Committee member) / Arizona State University (Publisher)
Created2014
Description
Previous research on experiences of the endowment effect and buyer's remorse has often failed to compare the two seemingly related phenomena. The current study attempts to provide a framework in which the two can be compared and to offer a possible suggestion as to when it may be beneficial to experience either the endowment effect or buyer's remorse, namely situations of resource scarcity versus abundance. The current study employed an online dating paradigm in which resource scarcity was operationalized as the sex ratio of users on the site. Two hundred and one participants were exposed to a favorable sex ratio, an unfavorable sex ratio, or a no information control condition and asked to bid on potential dates. Once matched with a potential date, participants were asked how willing they would be to give up their date and the minimum amount of points they would request to do so. These dependent variables served as indicators of experiences of the endowment effect or buyer's remorse. Results indicated that the sex ratio of the online dating site did not influence experiences of the endowment effect versus buyer's remorse. Potential mediators and moderators were also investigated although no significant effects were found. Possible reasons for the null results are discussed as well as future directions.
ContributorsMeyer, Kaitlin (Author) / Cohen, Adam B. (Thesis advisor) / Kenrick, Douglas (Committee member) / Neuberg, Steven (Committee member) / Arizona State University (Publisher)
Created2014