The influence of the hanger configuration in the arch and deck bending moments under asymmetric loads is widely used nowadays for improved designs of arch bridges. In this work, by means of a parametric study, those hanger configurations that most efficiently increase both the natural frequencies and buckling factors are identified, simultaneously evaluating the dynamic and static performance of timber arch footbridges. A parametric FEM model allows to evaluate the performance of vertical, Nielsen, fan and network hanger configurations together with combinations of them among others for a three-hinge timber arch. The impact of other relevant design choices such as the number of hinges in the arch or the arch slenderness ratio is jointly addressed allowing for design recommendations. The results show a convergence of the natural frequencies regardless of the configuration of the hangers when increasing the number of them. Moreover, the performance of the studied hanger configurations is improved by introducing inclined hangers significantly increasing natural frequencies and buckling factors of the system. This highlights the importance of the stabilizing horizontal reaction appearing at the deck hanger anchor points and thereby improving the bending moment distribution at the arch. Furthermore, the analyses show that the combination of Nielsen and vertical hangers achieves both the largest natural frequency and buckling factor for a reasonable number of hangers. This contrasts with the low sensitivity of the static and dynamic performance that the vertical hanger configuration shows in relation to changes in the number of hangers, arch rise or arch stiffness among others. Additionally, an important consideration when designing three hinge arch bridges is found to be to prevent a local buckling mode from appearing at the crown of the arch. This can also be done by the right choice of the number and configuration of hangers, as has been shown in the thesis. The results produced in this work can be used to guide engineers towards designing arch bridges with higher static capacity and better dynamic performance while reducing at the same time the material consumption. Furthermore, the findings of the work open up the way towards optimization of arch bridge structures.

Indiana University-Purdue University Indianapolis (IUPUI) / Tooth mass discrepancies have been studied extensively in Caucasian populations, but little has been done to compare differences between Caucasian and African-American populations. The objective of this study was to determine whether the incidence of tooth mass discrepancies between the maxillary and mandibular arches was greater in African-American populations than Caucasian populations. Pretreatment plaster orthodontic models of 100 African-American and 100 Caucasian patients from the Indiana University Orthodontic Clinic and from one private practitioner were measured with a Mitutoyo Digimatic® caliper accurate to 0.01 mm. Mesiodistal widths of all teeth from first molar to first molar were measured with the mesio-buccal and disto-buccal contact areas normally being the widest area. The investigator was blinded to the gender and ethnicity of the subject by assigning each model a random number which was matched to the patient profile only following statistical analysis. Anterior ratios and total (posterior+ anterior) ratios were calculated according to the methods described by Bolton and were compared to the Bolton means and standard deviations. Incidence of tooth mass discrepancy was also investigated according to gender and dental malocclusion classification of the individuals. Tooth mass discrepancies present a hurdle to the clinician in achieving an ideal occlusion. Reports of the incidence of significant discrepancies in defined populations alerts the practitioner to problems in finishing their patients' occlusions. Results of the study show nearly double the incidence of overall Bolton tooth mass discrepancy in the African-American sample than in the Caucasian. The overall tooth mass discrepancy was more severe in the African-American sample, while anterior tooth mass discrepancies were nearly identical in both populations.

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No description available.

No description available.

No description available.

Covid19 hit the world’s financial markets by surprise in March 2020 and ensuing volatility marked an end to the prior low-volatility environment. This Black Swan engendered numerous publications establishing how the equity market responded to the exogenous shock. However, there is no applicable comparison to Nasdaq100 regarding how models perform during extreme conditions such as ante, amid and post Covid19. Furthermore, goodness of fit together with forecasting accuracy are further examined in the light of new intra-day data from Oxford Man Institute covering this time-period. This thesis presents a comparison of volatility models incorporating economic intuition, sentiment, historical values of volatility and stochastics. By exploiting intra-day at 5 min interval the trade-off between noise and loss of valuable information effectively kept at a minimum yielding considerable robustness to the thesis’ result. Linear ARCH-models, Implied Volatility and HARRV applied with the addition of several different combinations of hold-out periods enable multiple vantagepoints for evaluation. This thesis finds HARRV’s series of one-step ahead prediction of future conditional volatility to be superior throughout all hold-out periods. I am able to present empirical evidence supporting the idea that HARRV’s additive cascades of volatility is superior to sentiment-driven implied volatility and ARCH-models pertaining to Nasdaq100.

A pressurized arch-shell structural component made of flexible material is considered. The component is inflated with high internal pressure. The behavior of similar types of structures, such as a pair of leaning pressurized arches and pressurized arch-supported membrane shelters, has been investigated in the past. More recently, several types of pressurized structures have been incorporated as part of the framework for a variety of structural systems. Particularly, the U.S. Army has been investigating the use of large lightweight and transportable pressurized arch-shell structures to be used as maintenance shelters for vehicles, helicopters, and airplanes. The formulated equations using thin shell theory are applied to a pressurized arch-shell component. A numerical investigation based on the Rayleigh-Ritz method is utilized to determine the behavior of arch-shells under various types of loading. The types of loading include a uniformly distributed vertical load representing snow, a wind load, and a horizontal side load distributed along the arc length. Deflections, stress resultants, and moments at various locations are computed for two types of shapes: circular and non-circular arch-shells. / Master of Science

this thesis Presents an exploration of the residence hall as an institution through formal and conceptual play. / Master of Architecture

As America's infrastructure ages, many of the nation's bridges approach the end of their service life. In order to develop a method for handling the rising number of deficient and functionally obsolete bridges, nondestructive tests and evaluations must be undertaken. Valuable information from these tests regarding the strength and condition of bridges will help in making decisions about their rehabilitation and replacement. Two adjoining open spandrel reinforced concrete arch bridges in downtown Appalachia, Virginia were selected for live load testing by Virginia Department of Transportation (VDOT). Both bridges have supported an increasing amount of extreme coal truck traffic throughout their service life and are essential to the efficient transport of coal in the region. Because of their age, having been built in 1929, and the amount of visible damage and repairs, VDOT was concerned about their remaining capacity and safe operation. The live load tests focused on global behavior characteristics such as service strain and deflection as well as local behavior of the arches surrounding significant repairs. It was found that the strain and deflection data collected during load testing displayed linear elastic behavior, indicating excess capacity beyond the test loads. Also, given the loading applied, the measured strains and deflections were small in magnitude, showing that the bridges are still acting as stiff structures and are in good condition. Data collected during these tests was compared to results from a finite element model of the bridges to determine the coal truck size which is represented by the live load test loading configurations. The model comparisons determined the test loads produced comparable deflections to those produced by the target coal truck load. Through this approach, a recommendation was given to VDOT regarding the satisfactory condition of the aging bridges to aid in the process of load rating and maintenance scheduling for the two bridges. / Master of Science