Matching Items (178)
Description
Concrete design has recently seen a shift in focus from prescriptive specifications to performance based specifications with increasing demands for sustainable products. Fiber reinforced composites (FRC) provides unique properties to a material that is very weak under tensile loads. The addition of fibers to a concrete mix provides additional ductility and reduces the propagation of cracks in the concrete structure. It is the fibers that bridge the crack and dissipate the incurred strain energy in the form of a fiber-pullout mechanism. The addition of fibers plays an important role in tunnel lining systems and in reducing shrinkage cracking in high performance concretes. The interest in most design situations is the load where cracking first takes place. Typically the post crack response will exhibit either a load bearing increase as deflection continues, or a load bearing decrease as deflection continues. These behaviors are referred to as strain hardening and strain softening respectively. A strain softening or hardening response is used to model the behavior of different types of fiber reinforced concrete and simulate the experimental flexural response. Closed form equations for moment-curvature response of rectangular beams under four and three point loading in conjunction with crack localization rules are utilized. As a result, the stress distribution that considers a shifting neutral axis can be simulated which provides a more accurate representation of the residual strength of the fiber cement composites. The use of typical residual strength parameters by standards organizations ASTM, JCI and RILEM are examined to be incorrect in their linear elastic assumption of FRC behavior. Finite element models were implemented to study the effects and simulate the load defection response of fiber reinforced shotcrete round discrete panels (RDP's) tested in accordance with ASTM C-1550. The back-calculated material properties from the flexural tests were used as a basis for the FEM material models. Further development of FEM beams were also used to provide additional comparisons in residual strengths of early age samples. A correlation between the RDP and flexural beam test was generated based a relationship between normalized toughness with respect to the newly generated crack surfaces. A set of design equations are proposed using a residual strength correction factor generated by the model and produce the design moment based on specified concrete slab geometry.
ContributorsBarsby, Christopher (Author) / Mobasher, Barzin (Thesis advisor) / Rajan, Subramaniam D. (Committee member) / Neithalath, Narayanan (Committee member) / Arizona State University (Publisher)
Created2011
Description
The nature of imperative syntax has remained an elusive, yet ever-present, subject in syntactic research, spanning several decades of linguistic inquiry and analysis, and it is therefore unsurprising that current views on the subject continue to be somewhat divided. This thesis examines the syntactic evidence from imperatives in Old English and ultimately seeks to develop a picture of the possibilities for imperative clauses in OE alongside an overall framework for imperative syntax within contemporary theoretical models of syntactic structure. The general, perceived pattern for OE imperative clauses (e.g. Millward 1971) is “verb−first,” and statistical data from the corpora confirm this perception, with the majority of imperative clauses exhibiting the verb in clause−initial position. Imperative constructions with post− and preverbal overt subjects are also examined at length, and postverbal subjects are found to be the majority case. These results are further expanded by examinations of data from verb−second and verb−third contexts, which include possibilities for topicalized constituents and adverbs. Ultimately, the relative position of both the verb and the subject and the relationship between these and other elements in the totality of the data provide essential clues for constructing a clearer model of OE imperative syntax. Within a relatively rich cartographic framework (Rizzi 1997), I therefore argue that the imperative verb is standardly fronted to the head of ForceP, with the overt subject remaining in spec−FinP, in parallel with other models for imperative syntax and OE syntax. Exceptions to this pattern for imperatives which suggest lower positions for the imperative verb (e.g. verb−second and verb−third constructions) are also accounted for, all with the central goal of demonstrating a consistent pattern underlying the realization of imperative syntax in Old English.
ContributorsKruger, William Wriley (Author) / Gelderen, Elly van (Thesis advisor) / Adams, Karen (Committee member) / Major, Roy (Committee member) / Arizona State University (Publisher)
Created2012
Description
Extensive cross-linguistic data document a wide gamut of semantic and pragmatic uses of the diminutive that revolve around the fundamental concepts of `small' and `child'. As typical inventory of informal registers, diminutives are utilized as pragmatic markers of politeness in a wide range of contextual meanings. This dissertation is intended to fill some major gaps in the systematic and empirical research on the formation and pragmatic uses of the diminutives in Macedonian and to explore the role of diminutivization in a broader linguistic framework, by examining the consistency of the field of diminutives, the core and peripheral meanings of the diminutive, their typology, as well as their pragmatic potential. The morphology and pragmatics of the diminutive is examined by combining data from electronic and printed sources, video recordings of natural conversations, as well as from material collected from participant and non-participant observations. At the level of morphology, it is argued that three fundamental semantic constraints underlie the formation of diminutives: [-big], [+ emotional], and [+ informal]. Furthermore, it is shown how diminutive combinability is rule governed in Macedonian by proposing sets of formal constraints for all grades of diminutives. At the level of pragmatics, the pragmatic functions of the diminutives proper and the related periphrastic diminutive malku are investigated in a variety of contexts involving child-directed speech (CDS) and adult communication. By analyzing the pragmatic functions of the diminutive in a series of speech acts, and drawing upon cross-cultural interpretations suggested by Wierzbicka (1991), it is argued that, in Macedonian, social bonding, cordiality, intimacy or affection are pragmatically more salient than personal autonomy in the Anglo-Saxon societies, realized through non-imposition, tentativeness, or similar pragmatic strategies for saving face. Additionally, it is contended that there exist cultural differences in the assessment of the concept of imposition between these societies. The analyses of the pragmatic potential of the diminutive proper and the periphrastic diminutive 'malku' give rise to the claim that Macedonian culture is predominantly founded on the pragmatic principle of positive politeness.
ContributorsSpasovski, Lupco (Author) / Adams, Karen L (Thesis advisor) / Gelderen, Elly van (Committee member) / Sipka, Danko (Committee member) / Arizona State University (Publisher)
Created2012
Description
The purpose of this study is to explore the syntax and pragmatics of subject doubling in spoken French. Many prescriptivists have considered it a redundant and ungrammatical form, but over the years, it has gained more interest from syntacticians. It is widely acknowledged that dislocations involve topics, but the position of these structures is very disputed. Some linguists believe in base generation while others state there is movement. The status of subject clitics also comes into play and their role as arguments or agreement markers is crucial to understanding the issues at stake with a topic analysis. It is often argued that the clitics are undergoing a linguistic cycle whereby they lose their function of argument, and need to be reinforced by disjunct pronouns. In this study, I examined which analyses support my data and I attempted to determine what structures tend to be most dislocated by looking at the environment of the discourse in a corpus of spoken French.
ContributorsBlanquart, Eleonore (Author) / Ossipov, Helene (Thesis advisor) / Bahtchevanova, Mariana (Thesis advisor) / Gelderen, Elly van (Committee member) / Arizona State University (Publisher)
Created2012
Description
Ultra-concealable multi-threat body armor used by law-enforcement is a multi-purpose armor that protects against attacks from knife, spikes, and small caliber rounds. The design of this type of armor involves fiber-resin composite materials that are flexible, light, are not unduly affected by environmental conditions, and perform as required. The National Institute of Justice (NIJ) characterizes this type of armor as low-level protection armor. NIJ also specifies the geometry of the knife and spike as well as the strike energy levels required for this level of protection. The biggest challenges are to design a thin, lightweight and ultra-concealable armor that can be worn under street clothes. In this study, several fundamental tasks involved in the design of such armor are addressed. First, the roles of design of experiments and regression analysis in experimental testing and finite element analysis are presented. Second, off-the-shelf materials available from international material manufacturers are characterized via laboratory experiments. Third, the calibration process required for a constitutive model is explained through the use of experimental data and computer software. Various material models in LS-DYNA for use in the finite element model are discussed. Numerical results are generated via finite element simulations and are compared against experimental data thus establishing the foundation for optimizing the design.
ContributorsVokshi, Erblina (Author) / Rajan, Subramaniam D. (Thesis advisor) / Neithalath, Narayanan (Committee member) / Mobasher, Barzin (Committee member) / Arizona State University (Publisher)
Created2012
Description
The current method of measuring thermal conductivity requires flat plates. For most common civil engineering materials, creating or extracting such samples is difficult. A prototype thermal conductivity experiment had been developed at Arizona State University (ASU) to test cylindrical specimens but proved difficult for repeated testing. In this study, enhancements to both testing methods were made. Additionally, test results of cylindrical testing were correlated with the results from identical materials tested by the Guarded Hot&ndashPlate; method, which uses flat plate specimens. In validating the enhancements made to the Guarded Hot&ndashPlate; and Cylindrical Specimen methods, 23 tests were ran on five different materials. The percent difference shown for the Guarded Hot&ndashPlate; method was less than 1%. This gives strong evidence that the enhanced Guarded Hot-Plate apparatus in itself is now more accurate for measuring thermal conductivity. The correlation between the thermal conductivity values of the Guarded Hot&ndashPlate; to those of the enhanced Cylindrical Specimen method was excellent. The conventional concrete mixture, due to much higher thermal conductivity values compared to the other mixtures, yielded a P&ndashvalue; of 0.600 which provided confidence in the performance of the enhanced Cylindrical Specimen Apparatus. Several recommendations were made for the future implementation of both test methods. The work in this study fulfills the research community and industry desire for a more streamlined, cost effective, and inexpensive means to determine the thermal conductivity of various civil engineering materials.
ContributorsMorris, Derek (Author) / Kaloush, Kamil (Thesis advisor) / Mobasher, Barzin (Committee member) / Phelan, Patrick E (Committee member) / Arizona State University (Publisher)
Created2011
Description
This report provides an overview of scramjet-powered hypersonic vehicle modeling and control challenges. Such vehicles are characterized by unstable non-minimum phase dynamics with significant coupling and low thrust margins. Recent trends in hypersonic vehicle research are summarized. To illustrate control relevant design issues and tradeoffs, a generic nonlinear 3DOF longitudinal dynamics model capturing aero-elastic-propulsive interactions for wedge-shaped vehicle is used. Limitations of the model are discussed and numerous modifications have been made to address control relevant needs. Two different baseline configurations are examined over a two-stage to orbit ascent trajectory. The report highlights how vehicle level-flight static (trim) and dynamic properties change over the trajectory. Thermal choking constraints are imposed on control system design as a direct consequence of having a finite FER margin. The implication of this state-dependent nonlinear FER margin constraint, the right half plane (RHP) zero, and lightly damped flexible modes, on control system bandwidth (BW) and FPA tracking has been discussed. A control methodology has been proposed that addresses the above dynamics while providing some robustness to modeling uncertainty. Vehicle closure (the ability to fly a trajectory segment subject to constraints) is provided through a proposed vehicle design methodology. The design method attempts to use open loop metrics whenever possible to design the vehicle. The design method is applied to a vehicle/control law closed loop nonlinear simulation for validation. The 3DOF longitudinal modeling results are validated against a newly released NASA 6DOF code.
ContributorsDickeson, Jeffrey James (Author) / Rodriguez, Armando A (Thesis advisor) / Tsakalis, Konstantinos (Committee member) / Si, Jennie (Committee member) / Wells, Valana (Committee member) / Kawski, Mattias (Committee member) / Arizona State University (Publisher)
Created2012
Description
Development of post-traumatic epilepsy (PTE) after traumatic brain injury (TBI) is a major health concern (5% - 50% of TBI cases). A significant problem in TBI management is the inability to predict which patients will develop PTE. Such prediction, followed by timely treatment, could be highly beneficial to TBI patients. Six male Sprague-Dawley rats were subjected to a controlled cortical impact (CCI). A 6mm piston was pneumatically driven 3mm into the right parietal cortex with velocity of 5.5m/s. The rats were subsequently implanted with 6 intracranial electroencephalographic (EEG) electrodes. Long-term (14-week) continuous EEG recordings were conducted. Using linear (coherence) and non-linear (Lyapunov exponents) measures of EEG dynamics in conjunction with measures of network connectivity, we studied the evolution over time of the functional connectivity between brain sites in order to identify early precursors of development of epilepsy. Four of the six TBI rats developed PTE 6 to 10 weeks after the initial insult to the brain. Analysis of the continuous EEG from these rats showed a gradual increase of the connectivity between critical brain sites in terms of their EEG dynamics, starting at least 2 weeks prior to their first spontaneous seizure. In contrast, for the rats that did not develop epilepsy, connectivity levels did not change, or decreased during the whole course of the experiment across pairs of brain sites. Consistent behavior of functional connectivity changes between brain sites and the "focus" (site of impact) over time was demonstrated for coherence in three out of the four epileptic and in both non-epileptic rats, while for STLmax in all four epileptic and in both non-epileptic rats. This study provided us with the opportunity to quantitatively investigate several aspects of epileptogenesis following traumatic brain injury. Our results strongly support a network pathology that worsens with time. It is conceivable that the observed changes in spatiotemporal dynamics after an initial brain insult, and long before the development of epilepsy, could constitute a basis for predictors of epileptogenesis in TBI patients.
ContributorsTobin, Edward (Author) / Iasemidis, Leonidas (Thesis advisor) / Tsakalis, Konstantinos (Committee member) / Muthuswamy, Jitendran (Committee member) / Arizona State University (Publisher)
Created2012
Description
Past research has isolated an extension of the copular verb estar into the domain previously sanctioned for its counterpart, ser. This extension has been found in areas of contact between American English and Spanish speaking Mexican immigrants. A similar situation of contact is in occurrence in Arizona, and this study endeavored to evaluate if this same extension was present, and to what degree. This study also explores the framework of linguistic hegemony in order to relate language attitudes in Arizona to language change in Arizona. The findings revealed minimal extension. This may be due to language maintenance in response to hegemony.
ContributorsBonnell, Jamie (Author) / Gelderen, Elly van (Thesis advisor) / Major, Roy (Committee member) / Ryan, John (Committee member) / Arizona State University (Publisher)
Created2012
Explaining Fukushima to children: a cross-cultural study of bodily functions as metaphor in Japanese
Description
This research proposes that a cross-cultural disconnect exists between Japanese and American English in the realm of bodily functions used as metaphor. Perhaps nowhere is this notion illustrated more clearly than by a cartoon that was inspired by recent tragic events in Japan. In the afternoon of Friday, March 11, 2011, the northeast coast of Japan was struck by a massive earthquake and tsunami that caused immeasurable loss of life and property and catastrophic damage to the nuclear power plant in Fukushima Prefecture. In the immediate wake of these events, Japanese artist Hachiya Kazuhiko, determined to make the situation comprehensible to children, created a cartoon in which he anthropomorphized the damaged Fukushima Daiichi reactor and likened the dangers associated with it to illness and bodily functions. This cartoon garnered considerable notoriety, both in Japan and abroad. The reactions of English speakers appeared to differ from those of Japanese speakers, suggesting the existence of a possible cross-cultural disconnect. This research into the reactions to the cartoon and other relevant literature (both in English and Japanese), viewed against federal regulations regarding the broadcast of "obscenity" in the United States, commentary on American society, and how the use of similar language in American cartoons is seen, clearly indicates that negative attitudes toward the use of bodily functions as metaphor exist in the United States, while the same usage is seen differently in Japan.
ContributorsHacker, Michael (Author) / Adams, Karen (Thesis advisor) / Gelderen, Elly van (Thesis advisor) / Prior, Matthew (Committee member) / Arizona State University (Publisher)
Created2012