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- Genre: Masters Thesis
Description
Pb-free solders are used as interconnects in various levels of micro-electronic packaging. Reliability of these interconnects is very critical for the performance of the package. One of the main factors affecting the reliability of solder joints is the presence of porosity which is introduced during processing of the joints. In this thesis, the effect of such porosity on the deformation behavior and eventual failure of the joints is studied using Finite Element (FE) modeling technique. A 3D model obtained by reconstruction of x-ray tomographic image data is used as input for FE analysis to simulate shear deformation and eventual failure of the joint using ductile damage model. The modeling was done in ABAQUS (v 6.10). The FE model predictions are validated with experimental results by comparing the deformation of the pores and the crack path as predicted by the model with the experimentally observed deformation and failure pattern. To understand the influence of size, shape, and distribution of pores on the mechanical behavior of the joint four different solder joints with varying degrees of porosity are modeled using the validated FE model. The validation technique mentioned above enables comparison of the simulated and actual deformation only. A more robust way of validating the FE model would be to compare the strain distribution in the joint as predicted by the model and as observed experimentally. In this study, to enable visualization of the experimental strain for the 3D microstructure obtained from tomography, a three dimensional digital image correlation (3D DIC) code has been implemented in MATLAB (MathWorks Inc). This developed 3D DIC code can be used as another tool to verify the numerical model predictions. The capability of the developed code in measuring local displacement and strain is demonstrated by considering a test case.
ContributorsJakkali, Vaidehi (Author) / Chawla, Nikhilesh K (Thesis advisor) / Jiang, Hanqing (Committee member) / Solanki, Kiran (Committee member) / Arizona State University (Publisher)
Created2011
Description
ABSTRACT The goal of this study is to use neoclassical realist methodology to add to the growing body of literature explaining why America is failing so horribly in its media war with militant Islamists. The general argument being conveyed is that inconsistencies in America's ostensibly liberal diplomacy strategy leaves it open to criticism and deprives it of the credibility necessary to muster an adequate rebuttal. To accomplish its aim, the analysis begins with an investigation into the origins of America's current liberal rhetorical approach. It is believed that with this sort look beneath the surface of the idealistic romanticism U.S. citizens have been continually conditioned to embrace, it becomes apparent that the grandiose pronouncements made by America's national political elite are actually based on rather dubious foundations. The evaluation then turns to a more focused rhetorical examination, which spans from the start of the so-called Arab Spring uprisings on December 18, 2010 to the delivery of President Obama's highly publicized State Department address regarding these demonstrations on May 19, 2011, in order to go behind the White House's official statements and uncover what truly motivated its policy decision making. The belief here is that a close review of the administration's abysmal performance during this historic period assists in making the inadequacy of America's current rhetorical narrative all the more evident. Finally, once the contradictory nature of contemporary American liberalism has been fully demonstrated, the last section concludes with an effort to explain why replacing America's liberal strategy with a straightforward realist stance is best for both American's relations with the Muslim world and America's overall security.
ContributorsThomas, John H., III (Author) / Mean, Lindsey (Thesis advisor) / Ramsey, Ramsey E (Committee member) / Nadesan, Majia (Committee member) / Arizona State University (Publisher)
Created2011
Description
As digital technology promises immediacy and interactivity in communication, sight and sound in motion graphics has expanded the range of design possibilities in advertising, social networking, and telecommunication beyond the visual realm. The experience of seeing has been greatly enriched by sound as visual solutions become dynamic and multi-dimensional. The ability to record and transfer sight and sound with new media has granted the designer more control in manipulating a viewer's experience of time and space. This control allows time-based form to become the foundation that establishes many interactive, multisensory and interdisciplinary applications. Is conventional design theory for print media adequate to effectively approach time-based form? If not, what is the core element that is required to balance the static and dynamic aspects of time in new media? Should time-related theories and methodologies from other disciplines be adopted into our design principles? If so, how would this knowledge be integrated? How can this experience in time be effectively transferred to paper? Unless the role of the time dimension in sight is operationally deconstructed and retained with sound, it is very challenging to control the design in this fugitive form. Time activation refers to how time and the perception of time can be manipulated for design and communication purposes. Sound, as a shortcut to the active time design element, not only encapsulates the structure of its "invisible" time-based form, but also makes changes in time conspicuously measurable and comparable. Two experiments reflect the influence of sound on imagery, a slideshow and video, as well as how the dynamics in time are represented across all design media. A cyclical time-based model is established to reconnect the conventional design principles learned in print media with time-based media. This knowledge helps expand static images to motion and encapsulate motion in stasis. The findings provide creative methods for approaching visualization, interactivity, and design education.
ContributorsCheung, Hoi Yan Patrick (Author) / Giard, Jacques (Thesis advisor) / Sanft, Alfred C (Committee member) / Aisling, Kelliher (Committee member) / Arizona State University (Publisher)
Created2011
Description
The goal of this research was to contribute to the understanding of how the physical design of Intensive Care Unit (ICU) environments may be improved to enhance nursing communication, and in turn, the quality and safety of patient outcomes. This study was guided by two research questions: (1) What are the major characteristics of nurse communication in a hybrid ICU nurse station design? (2) What are the factors in the built environment that enhance or hinder nurse communication in a hybrid ICU nurse station design? The research design was exploratory and qualitative. Observations were conducted in two ICUs with hybrid nurse station layouts. Participant observation was used to systematically observe and document nurse communication and the physical attributes of the ICU nurse work environment that affect communication. Literature, observations, and information regarding staffing and design about the selected ICUs were analyzed for the generation of concepts and the exploration of significant themes. Results show that nurse interactions with other staff members varied within the different zones of the ICU pod. A biaxial map illustrates four key types of core nurse communication interactions: At ease, On guard, In motion, and On the edge. The quadrants representing barriers to nurse communication are On guard and On the edge, and included interactions with other staff members in the pod. The quadrants representing facilitators to nurse communication are At ease and In motion. The hybrid nurse station layout supported nurse-nurse communication, but not communication interactions with other staff members present on the pod. The results provide a broad understanding of how nurse communication is affected by the environment in which nurses work, and allows for the emergence of design opportunities to enhance nurse communication.
ContributorsNewcomb, Emily Michelle Darling (Author) / Lamb, Gerri (Thesis advisor) / Stein, Morris (Thesis advisor) / Wolf, Peter (Committee member) / Arizona State University (Publisher)
Created2011
Description
The division of domestic labor has far-reaching implications for "private" life (e.g. relational satisfaction and conflict) and for "public" paid labor (e.g. time and dedication in the workplace and career advancement). Although several theories have been developed and tested, they do not sufficiently explain the consistent findings that women in mixed sex households perform a majority of the domestic labor. Without understanding the causes for differences in task performance, past research encouraging communicative solutions to ameliorate conflict was ineffective in changing task allocation and performance. Therefore, it is necessary to understand theoretical explanations that drive domestic labor behavior to develop effective solutions. The recent integrative theory of the division of domestic labor attempts to explain how individuals interact with household partners to allocate domestic tasks. Recognizing the complexity of the division of domestic labor, the integrative theory considers individual, dyadic, and societal factors that influence task allocation. Because clear differences in task performance have been found in mixed sex households, this study separates sex and gender as distinct variables by considering same-sex roommate relationships, essentially removing sex differences from the living arrangement. Furthermore, this study considers individual threshold levels as described by the integrative theory in order to test the theoretical underpinnings. Specifically, this study is designed to investigate the relationships between individual cleanliness threshold levels and gender, sex, perceptions of satisfaction, equity, and frequency of conflict in same-sex roommate relationships. Results indicate support of the integrative theory of the division of domestic labor. Regarding gender differences, partial support for the theory appeared in that feminine individuals have lower threshold levels than masculine individuals. Regarding sex differences, women possess lower individual threshold levels (i.e. more bothered when a task is undone) compared to men, which likely accounts for why existing research indicates that women spend more time performing domestic tasks. What is more, individuals with higher threshold levels report greater relational satisfaction. Further, individuals whose threshold levels differ from their living partner report lower relational satisfaction and greater conflict frequency. Finally, in terms of equity, both overbenefited and underbenefited individuals experience more conflict than those who feel their relationship is equitable. These results provide theoretical support for the integrative theory of the division of labor. Furthermore, the development and testing of a threshold measure scale can be used practically for future research and for better roommate pairings by universities. In addition, communication scholars, family practitioners and counselors, and universities can apply these theoretically grounded research findings to develop and test strategies to reduce conflict and increase relational satisfaction among roommates and couples.
ContributorsRiforgiate, Sarah (Author) / Alberts, Jess K. (Thesis advisor) / Mongeau, Paul (Thesis advisor) / Roberto, Anthony (Committee member) / Romero, Mary (Committee member) / Arizona State University (Publisher)
Created2011
Description
Image processing in canals, rivers and other bodies of water has been a very important concern. This research using Image Processing was performed to obtain a photographic evidence of the data of the site which helps in monitoring the conditions of the water body and the surroundings. Images are captured using a digital camera and the images are stored onto a datalogger, these images are retrieved using a cellular/ satellite modem. A MATLAB program was designed to obtain the level of water by just entering the file name into to the program, a curve fit model was created to determine the contrast parameters. The contrast parameters were obtained using the data obtained from the gray scale image mainly the mean and variance of the intensity values. The enhanced images are used to determine the level of water by taking pixel intensity plots along the region of interest. The level of water obtained is accurate to less than 2% of the actual level of water observed from the image. High speed imaging in micro channels have various application in industrial field, medical field etc. In medical field it is tested by using blood samples. The experimental procedure proposed determines the flow duration and the defects observed in these channel using a fluid introduced into the micro channel the fluid being water based dye and whole milk. The viscosity of the fluid shows different types of flow patterns and defects in the micro channel. The defects observed vary from a small effect to the flow pattern to an extreme defect in the channel such as obstruction of flow or deformation in the channel. The sample needs to be further analyzed by SEM to get a better insight on the defects.
ContributorsShasedhara, Abhijeet Bangalore (Author) / Lee, Taewoo (Thesis advisor) / Huang, Huei-Ping (Committee member) / Chen, Kangping (Committee member) / Arizona State University (Publisher)
Created2011
Description
ABSTRACT Epilepsy is a neurological condition that sometimes pervades all domains of an affected child's life. At school, three specific threats to the wellbeing of children with epilepsy exist: (1) seizure-related injuries, (2) academic problems, and (3) stigmatization. Unfortunately, educators frequently fail to take into account educationally-relevant epilepsy information when making important decisions. One possible explanation for this is that parents are not sharing such information with teachers. This study surveyed 16 parents of children with epilepsy in order to determine the rate at which they disclosed the epilepsy diagnoses to their children's teachers, as well as the difficulty with which they made the decision to disclose or withhold such information. In addition, the relationships between such disclosure and parent-participants' perceptions of the risks of epilepsy-related injuries, academic struggles, and stigmatization at school were examined. Results indicate that all participants disclosed their children's epilepsy diagnoses to their children's teachers, and most (69%) reported that making this decision was "very easy." There were no statistically significant associations between disclosure and any of three parental perception variables (perceptions of the threats of injury, academic problems, and stigmatization at school). Limitations, implications, and directions for future research are discussed.
ContributorsBush, Vanessa (Author) / Wodrich, David L (Committee member) / Blanchard, Jay (Committee member) / Gorin, Joanna (Committee member) / Arizona State University (Publisher)
Created2011
Description
Mostly, manufacturing tolerance charts are used these days for manufacturing tolerance transfer but these have the limitation of being one dimensional only. Some research has been undertaken for the three dimensional geometric tolerances but it is too theoretical and yet to be ready for operator level usage. In this research, a new three dimensional model for tolerance transfer in manufacturing process planning is presented that is user friendly in the sense that it is built upon the Coordinate Measuring Machine (CMM) readings that are readily available in any decent manufacturing facility. This model can take care of datum reference change between non orthogonal datums (squeezed datums), non-linearly oriented datums (twisted datums) etc. Graph theoretic approach based upon ACIS, C++ and MFC is laid out to facilitate its implementation for automation of the model. A totally new approach to determining dimensions and tolerances for the manufacturing process plan is also presented. Secondly, a new statistical model for the statistical tolerance analysis based upon joint probability distribution of the trivariate normal distributed variables is presented. 4-D probability Maps have been developed in which the probability value of a point in space is represented by the size of the marker and the associated color. Points inside the part map represent the pass percentage for parts manufactured. The effect of refinement with form and orientation tolerance is highlighted by calculating the change in pass percentage with the pass percentage for size tolerance only. Delaunay triangulation and ray tracing algorithms have been used to automate the process of identifying the points inside and outside the part map. Proof of concept software has been implemented to demonstrate this model and to determine pass percentages for various cases. The model is further extended to assemblies by employing convolution algorithms on two trivariate statistical distributions to arrive at the statistical distribution of the assembly. Map generated by using Minkowski Sum techniques on the individual part maps is superimposed on the probability point cloud resulting from convolution. Delaunay triangulation and ray tracing algorithms are employed to determine the assembleability percentages for the assembly.
ContributorsKhan, M Nadeem Shafi (Author) / Phelan, Patrick E (Thesis advisor) / Montgomery, Douglas C. (Committee member) / Farin, Gerald (Committee member) / Roberts, Chell (Committee member) / Henderson, Mark (Committee member) / Arizona State University (Publisher)
Created2011
Description
The original mediums were not texts or technologies; they were ritual actors performing acts of mediumship. Mediating between determined norms (the status quo) and emergent trends (change), they invoked divine authority to conjure meanings that proved adaptive, nonadaptive and/or maladaptive. With the advent of the written word, ritual became formalized and codified. The medium became a communication device, something abstract and external to the human condition. It then became possible to speak of "media effects" imposing influence in a logical deterministic manner. Yet with the advent of new media, we are witnessing a return to modes of cultural discourse that are spontaneous, interactive, communal and unscripted, all hallmarks of ritual action. This "ritual return" centers on the emergence of the "prosumer" (producer/consumer), a figure actively engaged in mediating practices. While resembling the original archaic "medium" in some respects, the prosumer is a "literate ritualist" allied with a multiplicity of cultural tribes. Thus the "new media" has given rise to "the new medium." The pages that follow focus on acts of contemporary mediumship, examining related concepts such as "ecology," "niche," "role," "affordance," and "trope." Each section considers how specific mediating practices afford and constrain modes of ritualized behavior. I call this practice-oriented approach to media studies "praxism."
ContributorsGyori, Bradford (Author) / Goggin, Maureen (Thesis advisor) / Baker, Aaron (Committee member) / Hjorleifur Jonsson (Committee member) / Arizona State University (Publisher)
Created2011
Description
Rotorcraft operation in austere environments can result in difficult operating conditions, particularly in the vicinity of sandy areas. The uplift of sediment by rotorcraft downwash, a phenomenon known as brownout, hinders pilot visual cues and may result in a potentially dangerous situation. Brownout is a complex multiphase flow problem that is not unique and depends on both the characteristics of the rotorcraft and the sediment. The lack of fundamental understanding constrains models and limits development of technologies that could mitigate the adverse effects of brownout. This provides the over-arching motivation of the current work focusing on models of particle-laden sediment beds. The particular focus of the current investigations is numerical modeling of near-surface fluid-particle interactions in turbulent boundary layers with and without coherent vortices superimposed on the background flow, that model rotorcraft downwash. The simulations are performed with two groups of particles having different densities both of which display strong vortex-particle interaction close to the source location. The simulations include cases with inter-particle collisions and gravitational settling. Particle effects on the fluid are ignored. The numerical simulations are performed using an Euler- Lagrange method in which a fractional-step approach is used for the fluid and with the particulate phase advanced using Discrete Particle Simulation. The objectives are to gain insight into the fluid-particle dynamics that influence transport near the bed by analyzing the competing effects of the vortices, inter-particle collisions, and gravity. Following the introduction of coherent vortices into the domain, the structures convect downstream, dissipate, and then recover to an equilibrium state with the boundary layer. The particle phase displays an analogous return to an equilibrium state as the vortices dissipate and the boundary layer recovers, though this recovery is slower than for the fluid and is sensitive to the particle response time. The effects of inter-particle collisions are relatively strong and apparent throughout the flow, being most effective in the boundary layer. Gravitational settling increases the particle concentration near the wall and consequently increase inter-particle collisions.
ContributorsMorales, Fernando (Author) / Squires, Kyle D. (Thesis advisor) / Wells, Valana L. (Committee member) / Calhoun, Ronald J. (Committee member) / Arizona State University (Publisher)
Created2011