Surge modeling is a tool used by engineers and utility owners in determining the surge pressures or transients that may result from routine pump and valve operations. Recent surge modeling work has focused on low and/or negative pressures within water distribution systems and how those occurrences could lead to intrusions. Effective surge modeling is needed in order to determine if the intrusion potential exists and what mitigation is needed to prevent intrusions. This work focuses on the generally unexplored area of using surge models to predict the location and duration of transient induced low and/or negative pressures within large complex water distribution systems. The studied system serves 350,000 people in the southeast United States, has 65 MGD of pumping capacity at two treatment plants, over 1500 miles of main and 12 storage tanks. This work focuses on the correlation between field data and the surge model using the author's extensive operational knowledge of the system, access to real-time SCADA data, and different celerity or wave speed values. This work also traces the steps taken by the author to locate areas within the system that experienced transient induced low and / or negative pressure.

Alcohol use in early adolescence is associated with numerous concurrent and future problems, including diagnosable alcohol use disorders. The trait of negative urgency, the tendency to act rashly when distressed, is an important predictor of alcohol-related dysfunction in youth and adults. The aim of this study was to test a model proposed by Cyders and Smith (2008) specifying a puberty-based developmental increase in negative urgency, which in turn predicts subsequent increases in early adolescent drinking. In a sample of 1,910 youth assessed semi- annually from spring of 5th grade through spring of 8th grade, we found support for this model. Pubertal onset was associated with both a mean increase and subsequent rises in negative urgency over time. Drinking frequency at any wave was predicted by prior wave assessments of drinking frequency, negative urgency, and pubertal onset. The slope of increase in drinking also increased as a function of pubertal onset. This model applied to negative urgency but not to other impulsivity-related traits. These findings highlight the importance of personality change in early adolescence as part of the risk matrix for early onset alcohol consumption.

Silicon is a promising negative electrode material for lithium-ion (Li-ion) batteries, with volumetric and gravimetric capacities much higher than those in current commercial batteries. Implementation of Si as a negative electrode is halted, however, by a large irreversible capacity and declining reversible capacity over cycle life. These problems are linked to the large volume expansion that Si undergoes when reacted with lithium, and overcoming them is the focus of this thesis. To overcome this expansion, in the first part titanium silicides were proposed to buffer the volume expansion problem as Ti does not react with Li and is robust. A pure phase of the targeted TiSi and TiSi2 was not achieved, however one product mixture containing TiSi2 and Ti5Si3 was cycled against Li at C/20. A capacity of 715 mAh g-1 was achieved, however rapid capacity fade occurred over the first 10 cycles. The second part of the thesis focused on heterostructured Si-Ge and Ge-Si core- shell nanowires. The morphology of the nanowires allows for better accommodation of strain due to lithiation, and Ge functions as an active matrix, as it can store Li in a similar manner as Si. The specific capacities of the nanowires were good at 1346 mAh g-1 and 1276 mAh g-1, however after 50 cycles the Si-Ge nanowires had a capacity retention of 72.4 % and the Ge-Si retained 62.4 %. The diffusion coefficient of Li was determined from GITT and EIS to be within the range of 10-16 to 10-13 cm2s-1 and was slightly lower than other reported values, attributed to the dense structure of the nanowires slowing diffusion.

Novel wave phenomena in two- and three-dimensional (2D and 3D) phononic crystals were investigated experimentally using ultrasonic techniques. Resonant tunneling of ultrasonic waves was successfully observed for the first time by measuring the transmission of ultrasound pulses through a double barrier consisting of two 3D phononic crystals separated by a cavity. This effect is the classical analogue of resonant tunneling of a quantum mechanical particle through a double potential barrier, in which transmission reaches unity at resonant frequencies. For phononic crystals, the tunneling peak was found to be less than unity, an effect that was explained by absorption. The dynamics of resonant tunneling was explored by measuring the group velocities of the ultrasonic pulses. Very slow and very fast velocities were found at frequencies close to and at the resonance, respectively. These extreme values are less than the speed of sound in air and greater than the speed of sound in any of the crystal’s constituent materials. Negative refraction and focusing effects in 2D phononic crystals were also observed. Negative refraction of ultrasound was demonstrated unambiguously in a prism-shaped 2D crystal at frequencies in the 2nd pass band where the wave vector and group velocity are opposite. The Multiple Scattering Theory and Snell’s law allowed theoretical predictions of the refraction angles. Excellent agreement was found between theory and experiment. The negative refraction experiments revealed a mechanism that can be used to focus ultrasound using a flat phononic crystal, and experiments to demonstrate the focusing of ultrasound emitted by several point sources were successfully carried out. The importance of using phononic crystals with circular equifrequency contours, as well as matching the size of the contours inside and outside the crystal, was established. Both conditions were satisfied by a flat phononic crystal of steel rods, in which the liquid inside the crystal (methanol) was different from the outside medium (water). The possibility of achieving subwavelength resolution using this phononic crystal was investigated with a subwavelength line source (a miniature strip-shaped transducer, approximately lambda/5 wide, where lambda is sound wavelength in water). A resolution of 0.55lambda was found, which is just above the diffraction limit lambda/2.

Purpose: The purpose of the study was to assess whether the extent to which consumers’ brand attitudes change when the consumers are exposed to negative publicity of the brand, and when exposed to a company’s response to negative publicity, differ depending on the consumers’ degree of brand loyalty and depending on how positive the consumers’ initial brand attitudes are. Design/methodology/approach: The study had a deductive research approach with a single cross-sectional descriptive and exploratory design. Archival analysis was used to collect relevant theories and to conduct the preparatory data collection through data mining, both in which secondary data was gathered. Survey was used when collecting qualitative primary data in the preparatory data collection through focus groups, and when collecting primary data in the main data collection through a questionnaire. The main data was further analyzed through a one-way ANOVA within a non-parametric Levene’s test. Findings: The extent to which consumers’ brand attitudes changed when consumers were exposed to negative publicity of the brand differed depending on if the consumers’ initial brand attitudes were positive or negative. Consumers with negative brand attitudes had a smaller attitude change compared to consumers with positive brand attitudes, opposed to what was assumed in the current study. The extent to which consumers’ brand attitudes changed when consumers were exposed to negative publicity of the brand did not statistically differ depending on the consumers’ degree of brand loyalty. Neither did the extent to which consumers’ brand attitudes changed when the consumers were exposed to a company’s response to negative publicity differ depending on how positive the consumers’ brand attitudes were, nor on the consumers’ degree of loyalty toward the brand. Research limitations/suggestions for future research: The information concerning the negative event and the company’s response strategy was very concentrated in the questionnaire. In real life, consumers would have had different perceptions of both the event and the response since some parts require consumers to actively search for information. Hence, suggestion for future research is to measure the attitude changes where the consumers have gained information in a natural course. Implications: The new perspective brought forth through the study could be useful for brand managers to bear in mind when setting up strategies on how to manage a negative publicity situation such as the Apple/Foxconn case.

Handprints and hand stencils are a ubiquitous element of rock art. For archaeologists, they represent a window onto the lives and communities of practice of prehistoric peoples. They are a means of recognizing the individual in the archaeological record and their contribution to the production of rock art. Children represent an understudied archaeological demographic despite comprising 50% of many prehistoric populations. In this thesis, I investigate the applicability of the 2D:4D ratio for sexing children’s hand stencils in a modern context. Based on a sample of 318 living children between the ages of 5 and 16 years old, I analyzed the degree of variance between the ratio derived from the soft-tissue measurements, and the ratio derived from a hand stencil created by the same child. The results of this research support my prediction that the 2D: 4D ratio cannot be used reliably to sex children’s hand stencils archaeologically. / Graduate / 0324 / amandarobins1@gmail.com

In this dissertation the proper determination and allowable signs of the effective parameters of metamaterial structures will be examined. First, a method that was commonly used to determine the presence of a negative index of refraction will be discussed. It will be shown that this method, which relies on the appearance of transmission peaks in the region where the real parts of the effective permittivity and permeability are expected to be negative, does not provide sufficient evidence that a negative index exists. Two alternate methods will then be presented that can be used to properly determine the sign of the index. Then, the form of the index in media that exhibit backward wave propagation will be examined from a purely three dimensional wave propagation point of view. It will be shown that in an isotropic medium backward wave propagation requires that the index be negative and in an anisotropic medium it requires that the index be negative along at least one of the three principal axes. In short, the necessary and sufficient condition for the negative index of refraction is the existence of the backward wave. Next, a technique commonly used to retrieve the effective parameters in metamaterials from transmission and reflection data will be considered. It will be shown that this retrieval technique can lead to unphysical claims that the imaginary parts of the effective permittivity or permeability can be negative even though the medium remains passive. By comparing the effective parameters obtained analytically and from the retrieval technique it will be shown that these unphysical claims are the result of error in the numerical simulations. The concepts of causality and analyticity will also be discussed by considering the Lorentzian model and it will be shown that this model does not allow the imaginary parts of the permittivity or permeability to be negative in the metamaterials consisting of split ring resonators and split wires.

The analysis and design of passive broadband negative group delay (NGD) transmission line phase shifters is presented. By extending the metamaterial transmission line concept to include loss, a NGD unit cell is proposed. Phase shifters are supplemented with NGD unit cells to produce a flattened phase response significantly increasing phase bandwidths. The design methodology of a NGD phase shifter is presented with consideration of nominal phase, frequency, impedance, maximum insertion loss and bandwidth. The relation between gain, bandwidth and group delay signifies a fundamental design limitation and tradeoff. A significant application of NGD phase shifters for removing beam squint in series fed antenna arrays is discussed. Several NGD phase shifters are fabricated and experimentally verified in the UHF band upwards of 1 GHz using planar microstrip transmission lines loaded with passive surface mount RF components with both positive and negative phase shifts.

In this dissertation the proper determination and allowable signs of the effective parameters of metamaterial structures will be examined. First, a method that was commonly used to determine the presence of a negative index of refraction will be discussed. It will be shown that this method, which relies on the appearance of transmission peaks in the region where the real parts of the effective permittivity and permeability are expected to be negative, does not provide sufficient evidence that a negative index exists. Two alternate methods will then be presented that can be used to properly determine the sign of the index. Then, the form of the index in media that exhibit backward wave propagation will be examined from a purely three dimensional wave propagation point of view. It will be shown that in an isotropic medium backward wave propagation requires that the index be negative and in an anisotropic medium it requires that the index be negative along at least one of the three principal axes. In short, the necessary and sufficient condition for the negative index of refraction is the existence of the backward wave. Next, a technique commonly used to retrieve the effective parameters in metamaterials from transmission and reflection data will be considered. It will be shown that this retrieval technique can lead to unphysical claims that the imaginary parts of the effective permittivity or permeability can be negative even though the medium remains passive. By comparing the effective parameters obtained analytically and from the retrieval technique it will be shown that these unphysical claims are the result of error in the numerical simulations. The concepts of causality and analyticity will also be discussed by considering the Lorentzian model and it will be shown that this model does not allow the imaginary parts of the permittivity or permeability to be negative in the metamaterials consisting of split ring resonators and split wires.

The analysis and design of passive broadband negative group delay (NGD) transmission line phase shifters is presented. By extending the metamaterial transmission line concept to include loss, a NGD unit cell is proposed. Phase shifters are supplemented with NGD unit cells to produce a flattened phase response significantly increasing phase bandwidths. The design methodology of a NGD phase shifter is presented with consideration of nominal phase, frequency, impedance, maximum insertion loss and bandwidth. The relation between gain, bandwidth and group delay signifies a fundamental design limitation and tradeoff. A significant application of NGD phase shifters for removing beam squint in series fed antenna arrays is discussed. Several NGD phase shifters are fabricated and experimentally verified in the UHF band upwards of 1 GHz using planar microstrip transmission lines loaded with passive surface mount RF components with both positive and negative phase shifts.