Impact of Large 0.7 Inch Strand on NU-I Girders

The NU I-Girder series uses a unique cross-section and high-strength concrete to achieve longer spans. The objective of this project was to develop the quality control and design criteria required to introduce 0.7 inch strands at 2 in. spacing in NU I-Girders. Compared to 0.5 inch strands, only 1/2 of the total number of strands would be needed. This would result in immediate labor savings in precast concrete product costs. More importantly, having the ability to introduce almost twice the prestressing force, compared to 0.5 inch strands, and 135% of the prestressing force, compared to 0.6 inch strands, could result in a significant increase in the span capacity of the current Nebraska Department of Roads (NDOR) NU I Girder without having to modify the sections or acquire new forms

Load Rating of Complex Bridges

The National Bridge Inspection Standards require highway departments to inspect, evaluate, and determine load ratings for structures defined as bridges located on all public roads. Load rating of bridges is performed to determine the live load that structures can safely carry at a given structural condition. Bridges are rated for three types of loads, design loads, legal loads, and permit loads, which is a laborious and time-consuming task as it requires the analysis of the structure under different load patterns. Several tools are currently available to assist bridge engineers to perform bridge rating in a consistent and timely manner. However, these tools support the rating of conventional bridge systems, such as slab, I-girder, box girder and truss bridges. In the last decade, NDOR has developed innovative bridge systems through research projects with the University of Nebraska-Lincoln. An example of these systems is tied-arch bridge system adopted in Ravenna Viaduct and Columbus Viaduct projects. The research projects dealt mainly with the design and construction of the new system, while overlooking the load rating. Therefore, there is a great need for procedures and models that assist in the load rating of these new and complex bridge systems. The objective of this project is to develop the procedures and models necessary for the load rating of tied-arch bridges, namely Ravenna and Columbus Viaducts. This includes developing refined analytical models of these structures and performing rating factor (RF) calculations in accordance to the latest Load and Resistance Factored Rating (LRFR) specifications. Two-dimensional and three-dimensional computer models were developed for each structure and RF calculations were performed for the primary structural components (i.e. arch, tie, hanger, and floor beam). RFs were calculated assuming various percentages of section loss and using the most common legal and permit loads in the state of Nebraska in addition to AASHTO LRFD live loads. In addition, the two structures were analyzed and RFs were calculated for an extreme event where one of the hangers is fully damaged

CONTINUOUSLY PRESTRESSED CONCRETE PILE SPLICE

A pile splice section for a spliced prestressed concrete pile includes a prestressed concrete element including a first end and a second end and a plurality of tendons that extend from the first end to the second end. A first end assembly at the first end of the prestressed concrete element includes a first plate coupled to the plurality of tendons. The first end assembly further includes a plurality of internally threaded fasteners embedded in the first end of the prestressed concrete element that are engagable via apertures extending through the first plate. A second end assembly at the second end of the prestressed concrete element includes a second metal plate coupled to the plurality of tendons. The second end assembly further includes a plurality of apertures extending through the second plate and accessible via pockets proximate the second end of the prestressed concrete element

CONTINUOUSLY PRESTRESSED CONCRETE PILE SPLICE

A pile splice section for a spliced prestressed concrete pile includes a prestressed concrete element including a first end and a second end and a plurality of tendons that extend from the first end to the second end. A first end assembly at the first end of the prestressed concrete element includes a first plate coupled to the plurality of tendons. The first end assembly further includes a plurality of internally threaded fasteners embedded in the first end of the prestressed concrete element that are engagable via apertures extending through the first plate. A second end assembly at the second end of the prestressed concrete element includes a second metal plate coupled to the plurality of tendons. The second end assembly further includes a plurality of apertures extending through the second plate and accessible via pockets proximate the second end of the prestressed concrete element

Automated advanced calibration and optimization of thermochemical models applied to biomass gasification and pyrolysis

This paper presents a methodology that combines physicochemical modeling with advanced statistical analysis algorithms as an efficient workflow, which is then applied to the optimization and design of biomass pyrolysis and gasification processes. The goal was to develop an automated flexible approach for the analyses and optimization of such processes. The approach presented here can also be directly applied to other biomass conversion processes and, in general, to all those processes for which a parametrized model is available. A flexible physicochemical model of the process is initially formulated. Within this model, a hierarchy of sensitive model parameters and input variables (process conditions) is identified, which are then automatically adjusted to calibrate the model and to optimize the process. Through the numerical solution of the underlying mathematical model of the process, we can understand how species concentrations and the thermodynamic conditions within the reactor evolve for the two processes studied. The flexibility offered by the ability to control any model parameter is critical in enabling optimization of both efficiency of the process as well as its emissions. It allows users to design and operate feedstock-flexible pyrolysis and gasification processes, accurately control product characteristics, and minimize the formation of unwanted byproducts (e.g., tar in biomass gasification processes) by exploiting various productivity-enhancing simulation techniques, such as parameter estimation, computational surrogate (reduced order model) generation, uncertainty propagation, and multi-response optimization

Cross-cultural adaptation of the condition-specific malocclusion impact questionnaire for the Malayalam-speaking population—a psychometric scale validation study

Objectives The study aimed to develop a regional version of the Malocclusion Impact Questionnaire (MIQ-Malayalam) for the Malayalam-speaking Indian population. Methods The English version of MIQ was translated into Malayalam through a rigorous translation process, followed by cross-cultural adaptation. Young people aged below 18 years who were just about to start orthodontic treatment were invited to complete the Malayalam version of MIQ along with the available native version of the Psychosocial Impact of Dental Aesthetics Questionnaire (PIDAQ). The MIQ-Malayalam was readministered after 14 days to assess test-retest reliability. Treatment need was assessed normatively using the Dental Health Component of the Index of Orthodontic Treatment Need (IOTN-DHC) and subjectively using Aesthetic Component of the Index of Orthodontic Treatment Need (IOTN-AC). Results A total of 210 subjects completed the questionnaires (males = 47.2%; females = 52.8%; age = 12-17 years, mean = 15 years and 3 months; standard deviation = 1.9) and 50 completed repeat questionnaires. Internal consistency and test-retest reliability were high (Cronbach’s alpha = 0.952; Intra-class Correlation Coefficient = 0.93). Exploratory factor analysis derived 4 factors with exclusion of 1 item. There were significant differences (P < .05) in MIQ scores between IOTN-DHC subgroups, ensuring discriminant validity. There was a high correlation between total MIQ and total PIDAQ scores (rho = 0.884), while low between total MIQ and IOTN-AC scores (rho = 0.203). Conclusion The Malayalam version of MIQ was found to be valid and reliable and can serve as a useful condition-specific measure of oral health-related quality of life

A theoretical and empirical investigation of nutritional label use

Due in part to increasing diet-related health problems caused, among others, by obesity, nutritional labelling has been considered important, mainly because it can provide consumers with information that can be used to make informed and healthier food choices. Several studies have focused on the empirical perspective of nutritional label use. None of these studies, however, have focused on developing a theoretical economic model that would adequately describe nutritional label use based on a utility theoretic framework. We attempt to fill this void by developing a simple theoretical model of nutritional label use, incorporating the time a consumer spends reading labels as part of the food choice process. The demand equations of the model are then empirically tested. Results suggest the significant role of several variables that flow directly from the model which, to our knowledge, have not been used in any previous empirical work

Virtual Compton Scattering and Neutral Pion Electroproduction in the Resonance Region up to the Deep Inelastic Region at Backward Angles

We have made the first measurements of the virtual Compton scattering (VCS) process via the H$(e,e'p)\gamma$ exclusive reaction in the nucleon resonance region, at backward angles. Results are presented for the $W$-dependence at fixed $Q^2=1$ GeV$^2$, and for the $Q^2$-dependence at fixed $W$ near 1.5 GeV. The VCS data show resonant structures in the first and second resonance regions. The observed $Q^2$-dependence is smooth. The measured ratio of H$(e,e'p)\gamma$ to H$(e,e'p)\pi^0$ cross sections emphasizes the different sensitivity of these two reactions to the various nucleon resonances. Finally, when compared to Real Compton Scattering (RCS) at high energy and large angles, our VCS data at the highest $W$ (1.8-1.9 GeV) show a striking $Q^2$- independence, which may suggest a transition to a perturbative scattering mechanism at the quark level.Comment: 20 pages, 8 figures. To appear in Phys.Rev.