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- Creators: Barrett, The Honors College
Description
The current research seeks to examine whether individuals display or downplay intelligence in various mating contexts. I hypothesized that both men and women should display fluid intelligence when attempting to attract a potential long-term partner, and that only men should display fluid intelligence when attempting to attract a potential short-term partner. Contrary to predictions, I find that men perform worse at a fluid intelligence test when motivated to attract a long-term partner. With respect to crystallized intelligence, I predicted that both men and women should display crystallized intelligence when attempting to attract a potential long-term partner, but women should downplay crystallized intelligence when attempting to attract a potential short-term partner. However, there were no effects of mating contexts on displays of crystallized intelligence.
ContributorsSng, Wei Sheng Oliver (Author) / Neuberg, Steven L. (Thesis advisor) / Kenrick, Douglas T. (Committee member) / Shiota, Michelle (Committee member) / Arizona State University (Publisher)
Created2013
Description
This project uses a functional approach to understand how members of stigmatized groups perceive emotional expressions on others' faces. The project starts from the premise that different groups are seen to pose different threats to others, and thus different groups face prejudices colored by different, specific negative emotions. For example, prejudice toward Black men is driven largely by fear, whereas prejudice toward obese people is driven largely by disgust. Members of these groups may thus come to be "expert" in perceiving fear or disgust in others' faces, depending on the specific emotional prejudices others feel toward their group. Alternatively, members of these groups may be biased to over- or under-perceive these emotional expressions on others' faces. I used a functional approach to predict that, if a Black man believes that seeing others' fear expressions will be useful to him, he will tend to overperceive fear on others' faces, whereas if an obese man believes that seeing others' disgust expressions will be useful to him, he will tend to overperceive disgust on others' faces. If, however, it is not considered useful to perceive these prejudicial emotions on others' faces, Black men and obese people will tend to underperceive these emotional expressions. This study recruited Black men, overweight men, and a group of comparison men. All participants completed an emotion detection task in which they rated faces on whether they expressed fear, disgust, or no emotion. Participants were randomly assigned to complete this emotion detection task either before or after a questionnaire designed to make salient, as well as to measure, participants' beliefs about others' prejudices and stereotypes of their group. Finally, participants completed a set of measures tapping predicted moderator variables. Results suggested that a) Black men tend to be less sensitive perceivers of both fear and disgust on others' faces than are other groups, unless prejudice is salient, and b) variables that would guide the functionality of perceiving others' prejudicial emotional expressions (e.g., belief that prejudice toward one's group is justified, belief that group status differences are legitimate, belief that one can manage stigmatizing interactions, stigma consciousness, and emotion-specific metastereotypes of one's group) do predict differences among Black men in perceiving these emotions on others' faces. Most results for overweight participants were null findings. The results' implications for the psychology of detecting prejudice, and emotional expressions more broadly, are discussed.
ContributorsNeel, Rebecca (Author) / Neuberg, Steven L. (Thesis advisor) / Shiota, Michelle N. (Committee member) / Becker, D. Vaughn (Committee member) / Kenrick, Douglas T. (Committee member) / Arizona State University (Publisher)
Created2013
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
Aluminum alloys and their composites are attractive materials for applications requiring high strength-to-weight ratios and reasonable cost. Many of these applications, such as those in the aerospace industry, undergo fatigue loading. An understanding of the microstructural damage that occurs in these materials is critical in assessing their fatigue resistance. Two distinct experimental studies were performed to further the understanding of fatigue damage mechanisms in aluminum alloys and their composites, specifically fracture and plasticity. Fatigue resistance of metal matrix composites (MMCs) depends on many aspects of composite microstructure. Fatigue crack growth behavior is particularly dependent on the reinforcement characteristics and matrix microstructure. The goal of this work was to obtain a fundamental understanding of fatigue crack growth behavior in SiC particle-reinforced 2080 Al alloy composites. In situ X-ray synchrotron tomography was performed on two samples at low (R=0.1) and at high (R=0.6) R-ratios. The resulting reconstructed images were used to obtain three-dimensional (3D) rendering of the particles and fatigue crack. Behaviors of the particles and crack, as well as their interaction, were analyzed and quantified. Four-dimensional (4D) visual representations were constructed to aid in the overall understanding of damage evolution. During fatigue crack growth in ductile materials, a plastic zone is created in the region surrounding the crack tip. Knowledge of the plastic zone is important for the understanding of fatigue crack formation as well as subsequent growth behavior. The goal of this work was to quantify the 3D size and shape of the plastic zone in 7075 Al alloys. X-ray synchrotron tomography and Laue microdiffraction were used to non-destructively characterize the volume surrounding a fatigue crack tip. The precise 3D crack profile was segmented from the reconstructed tomography data. Depth-resolved Laue patterns were obtained using differential-aperture X-ray structural microscopy (DAXM), from which peak-broadening characteristics were quantified. Plasticity, as determined by the broadening of diffracted peaks, was mapped in 3D. Two-dimensional (2D) maps of plasticity were directly compared to the corresponding tomography slices. A 3D representation of the plastic zone surrounding the fatigue crack was generated by superimposing the mapped plasticity on the 3D crack profile.
ContributorsHruby, Peter (Author) / Chawla, Nikhilesh (Thesis advisor) / Solanki, Kiran (Committee member) / Liu, Yongming (Committee member) / Arizona State University (Publisher)
Created2014
Description
Concrete is the most widely used infrastructure material worldwide. Production of portland cement, the main binding component in concrete, has been shown to require significant energy and account for approximately 5-7% of global carbon dioxide production. The expected continued increased use of concrete over the coming decades indicates this is an ideal time to implement sustainable binder technologies. The current work aims to explore enhanced sustainability concretes, primarily in the context of limestone and flow. Aspects such as hydration kinetics, hydration product formation and pore structure add to the understanding of the strength development and potential durability characteristics of these binder systems. Two main strategies for enhancing this sustainability are explored in this work: (i) the use of high volume limestone in combination with other alternative cementitious materials to decrease the portland cement quantity in concrete and (ii) the use of geopolymers as the binder phase in concrete. The first phase of the work investigates the use of fine limestone as cement replacement from the perspective of hydration, strength development, and pore structure. The nature of the potential synergistic benefit of limestone and alumina will be explored. The second phase will focus on the rheological characterization of these materials in the fresh state, as well as a more general investigation of the rheological characterization of suspensions. The results of this work indicate several key ideas. (i) There is a potential synergistic benefit for strength, hydration, and pore structure by using alumina and in portland limestone cements, (ii) the limestone in these systems is shown to react to some extent, and fine limestone is shown to accelerate hydration, (iii) rheological characteristics of cementitious suspensions are complex, and strongly dependent on several key parameters including: the solid loading, interparticle forces, surface area of the particles present, particle size distribution of the particles, and rheological nature of the media in which the particles are suspended, and (iv) stress plateau method is proposed for the determination of rheological properties of concentrated suspensions, as it more accurately predicts apparent yield stress and is shown to correlate well with other viscoelastic properties of the suspensions.
ContributorsVance, Kirk (Author) / Neithalath, Narayanan (Thesis advisor) / Rajan, Subramaniam D. (Committee member) / Mobasher, Barzin (Committee member) / Chawla, Nikhilesh (Committee member) / Marzke, Robert (Committee member) / Arizona State University (Publisher)
Created2014
Description
For decades, microelectronics manufacturing has been concerned with failures related to electromigration phenomena in conductors experiencing high current densities. The influence of interconnect microstructure on device failures related to electromigration in BGA and flip chip solder interconnects has become a significant interest with reduced individual solder interconnect volumes. A survey indicates that x-ray computed micro-tomography (µXCT) is an emerging, novel means for characterizing the microstructures' role in governing electromigration failures. This work details the design and construction of a lab-scale µXCT system to characterize electromigration in the Sn-0.7Cu lead-free solder system by leveraging in situ imaging.
In order to enhance the attenuation contrast observed in multi-phase material systems, a modeling approach has been developed to predict settings for the controllable imaging parameters which yield relatively high detection rates over the range of x-ray energies for which maximum attenuation contrast is expected in the polychromatic x-ray imaging system. In order to develop this predictive tool, a model has been constructed for the Bremsstrahlung spectrum of an x-ray tube, and calculations for the detector's efficiency over the relevant range of x-ray energies have been made, and the product of emitted and detected spectra has been used to calculate the effective x-ray imaging spectrum. An approach has also been established for filtering `zinger' noise in x-ray radiographs, which has proven problematic at high x-ray energies used for solder imaging. The performance of this filter has been compared with a known existing method and the results indicate a significant increase in the accuracy of zinger filtered radiographs.
The obtained results indicate the conception of a powerful means for the study of failure causing processes in solder systems used as interconnects in microelectronic packaging devices. These results include the volumetric quantification of parameters which are indicative of both electromigration tolerance of solders and the dominant mechanisms for atomic migration in response to current stressing. This work is aimed to further the community's understanding of failure-causing electromigration processes in industrially relevant material systems for microelectronic interconnect applications and to advance the capability of available characterization techniques for their interrogation.
In order to enhance the attenuation contrast observed in multi-phase material systems, a modeling approach has been developed to predict settings for the controllable imaging parameters which yield relatively high detection rates over the range of x-ray energies for which maximum attenuation contrast is expected in the polychromatic x-ray imaging system. In order to develop this predictive tool, a model has been constructed for the Bremsstrahlung spectrum of an x-ray tube, and calculations for the detector's efficiency over the relevant range of x-ray energies have been made, and the product of emitted and detected spectra has been used to calculate the effective x-ray imaging spectrum. An approach has also been established for filtering `zinger' noise in x-ray radiographs, which has proven problematic at high x-ray energies used for solder imaging. The performance of this filter has been compared with a known existing method and the results indicate a significant increase in the accuracy of zinger filtered radiographs.
The obtained results indicate the conception of a powerful means for the study of failure causing processes in solder systems used as interconnects in microelectronic packaging devices. These results include the volumetric quantification of parameters which are indicative of both electromigration tolerance of solders and the dominant mechanisms for atomic migration in response to current stressing. This work is aimed to further the community's understanding of failure-causing electromigration processes in industrially relevant material systems for microelectronic interconnect applications and to advance the capability of available characterization techniques for their interrogation.
ContributorsMertens, James Charles Edwin (Author) / Chawla, Nikhilesh (Thesis advisor) / Alford, Terry (Committee member) / Jiao, Yang (Committee member) / Neithalath, Narayanan (Committee member) / Arizona State University (Publisher)
Created2015
Description
Attachment relationships serve a variety of important functions for infants and adults. Despite the importance of attachment relationships in adults, the mechanisms that underlie the formation or maintenance of these kinds of relationships outside of romantic relationships remains chronically understudied. The current research investigated whether the mechanism of synchrony, which is associated with attachment formation in the parent-infant literature, may still be tied to attachment in adults. To measure this association, these studies showed participants videos to prime synchrony, and then measured activation of attachment concepts in a word completion task. The results of Experiment 1 showed that attachment style moderated the effects of the video prime such that those who were securely attached showed activation of attachment concepts while watching the Synchrony video. Those with a preoccupied attachment style showed activation of attachment concepts when they viewed the Asynchrony video. Those with a dismissive attachment style showed an unhypothesized activation of social distance concepts when viewing the Synchrony video. Experiment 2 suggested an overall effect of the Synchrony video on activation of attachment concepts. However, there was no effect of attachment style on these results. Limits of these studies and future directions are discussed.
ContributorsYee, Claire Ida (Author) / Shiota, Michelle L (Thesis advisor) / Neuberg, Steven L. (Committee member) / Kenrick, Douglas T. (Committee member) / Glenberg, Arthur (Committee member) / Arizona State University (Publisher)
Created2015
Description
As one of the most promising materials for high capacity electrode in next generation of lithium ion batteries, silicon has attracted a great deal of attention in recent years. Advanced characterization techniques and atomic simulations helped to depict that the lithiation/delithiation of silicon electrode involves processes including large volume change (anisotropic for the initial lithiation of crystal silicon), plastic flow or softening of material dependent on composition, electrochemically driven phase transformation between solid states, anisotropic or isotropic migration of atomic sharp interface, and mass diffusion of lithium atoms. Motivated by the promising prospect of the application and underlying interesting physics, mechanics coupled with multi-physics of silicon electrodes in lithium ion batteries is studied in this dissertation. For silicon electrodes with large size, diffusion controlled kinetics is assumed, and the coupled large deformation and mass transportation is studied. For crystal silicon with small size, interface controlled kinetics is assumed, and anisotropic interface reaction is studied, with a geometry design principle proposed. As a preliminary experimental validation, enhanced lithiation and fracture behavior of silicon pillars via atomic layer coatings and geometry design is studied, with results supporting the geometry design principle we proposed based on our simulations. Through the work documented here, a consistent description and understanding of the behavior of silicon electrode is given at continuum level and some insights for the future development of the silicon electrode are provided.
ContributorsAn, Yonghao (Author) / Jiang, Hanqing (Thesis advisor) / Chawla, Nikhilesh (Committee member) / Phelan, Patrick (Committee member) / Wang, Yinming (Committee member) / Yu, Hongyu (Committee member) / Arizona State University (Publisher)
Created2014
Description
Increasing demand for high strength powder metallurgy (PM) steels has resulted in the development of dual phase PM steels. In this work, the effects of thermal aging on the microstructure and mechanical behavior of dual phase precipitation hardened powder metallurgy (PM) stainless steels of varying ferrite-martensite content were examined. Quantitative analyses of the inherent porosity and phase fractions were conducted on the steels and no significant differences were noted with respect to aging temperature. Tensile strength, yield strength, and elongation to fracture all increased with increasing aging temperature reaching maxima at 538oC in most cases. Increased strength and decreased ductility were observed in steels of higher martensite content. Nanoindentation of the individual microconstituents was employed to obtain a fundamental understanding of the strengthening contributions. Both the ferrite and martensite hardness values increased with aging temperature and exhibited similar maxima to the bulk tensile properties. Due to the complex non-uniform stresses and strains associated with conventional nanoindentation, micropillar compression has become an attractive method to probe local mechanical behavior while limiting strain gradients and contributions from surrounding features. In this study, micropillars of ferrite and martensite were fabricated by focused ion beam (FIB) milling of dual phase precipitation hardened powder metallurgy (PM) stainless steels. Compression testing was conducted using a nanoindenter equipped with a flat punch indenter. The stress-strain curves of the individual microconstituents were calculated from the load-displacement curves less the extraneous displacements of the system. Using a rule of mixtures approach in conjunction with porosity corrections, the mechanical properties of ferrite and martensite were combined for comparison to tensile tests of the bulk material, and reasonable agreement was found for the ultimate tensile strength. Micropillar compression experiments of both as sintered and thermally aged material allowed for investigation of the effect of thermal aging.
ContributorsStewart, Jennifer (Author) / Chawla, Nikhilesh (Thesis advisor) / Jiang, Hanqing (Committee member) / Krause, Stephen (Committee member) / Arizona State University (Publisher)
Created2011
Description
The mechanical behavior of Pb-free solder alloys is important, since they must maintain mechanical integrity under thermomechanical fatigue, creep, and mechanical shock conditions. Mechanical shock, in particular, has become an increasing concern in the electronics industry, since electronic packages can be subjected to mechanical shock by mishandling during manufacture or by accidental dropping. In this study, the mechanical shock behavior of Sn and Sn-Ag-Cu alloys was systematically analyzed over the strain rate range 10-3 - 30 s-1 in bulk samples, and over 10-3 - 12 s-1 on the single solder joint level. More importantly, the influences of solder microstructure and intermetallic compounds (IMC) on mechanical shock resistance were quantified. A thorough microstructural characterization of Sn-rich alloys was conducted using synchrotron x-ray computed tomography. The three-dimensional morphology and distribution of contiguous phases and precipitates was analyzed. A multiscale approach was utilized to characterize Sn-rich phases on the microscale with x-ray tomography and focused ion beam tomography to characterize nanoscale precipitates. A high strain rate servohydraulic test system was developed in conjunction with a modified tensile specimen geometry and a high speed camera for quantifying deformation. The effect of microstructure and applied strain rate on the local strain and strain rate distributions were quantified using digital image correlation. Necking behavior was analyzed using a novel mirror fixture, and the triaxial stresses associated with necking were corrected using a self-consistent method to obtain the true stress-true strain constitutive behavior. Fracture mechanisms were quantified as a function of strain rate. Finally, the relationship between solder microstructure and intermetallic compound layer thickness with the mechanical shock resistance of Sn-3.8Ag-0.7Cu solder joints was characterized. It was found that at low strain rates the dynamic solder joint strength was controlled by the solder microstructure, while at high strain rates it was controlled by the IMC layer. The influences of solder microstructure and IMC layer thickness were then isolated using extended reflow or isothermal aging treatments. It was found that at large IMC layer thicknesses the trend described above does not hold true. The fracture mechanisms associated with the dynamic solder joint strength regimes were analyzed.
ContributorsYazzie, Kyle (Author) / Chawla, Nikhilesh (Thesis advisor) / Sane, Sandeep (Committee member) / Jiang, Hanqing (Committee member) / Krause, Stephen (Committee member) / Arizona State University (Publisher)
Created2012