Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 33 for “"Time Dependent Effects"”.
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Analysis of time-dependent effects on segmental prestressed concrete curved box-girder bridges
… and a computer program is developed for the time-dependent analysis of segmentally erected curved prestressed box-girder bridges and other structures. The program is capable of predicting the response of such structures throughout their various stages of construction and service load history. …
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Advanced beam finite element models with warping and bond-slip for concrete structures: addressing objectivity issues, prestressing and time-dependent effects [Modelli avanzati di elementi di trave con warping e bond-slip per strutture in calcestruzzo: analisi dei problemi di oggettività, precompressione ed effetti dipendenti dal tempo]
Questa tesi indaga formulazioni avanzate di elementi finiti di trave per l’analisi non lineare di telai in calcestruzzo armato (RC), precompresso (PC) e compositi, con l’obiettivo di migliorare l’accuratezza numerica e meccanica mantenendo al contempo un’elevata efficienza computazionale. Il lavoro …
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Development of a Composite Concrete Bridge System for Short-to-Medium-Span Bridges
… and reduces the likelihood of cracking due to time dependent effects. The effects of transverse bending due to concentrated wheel loads are investigated with respect to reflective cracking. Transverse bending moment are quantified and compared to transverse moment capacities provided by a …
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Approaches for Handling Time-Varying Covariates in Survival Models
Survival models are used in analysing time-to-event data. This type of data is very common in medical research. The Cox proportional hazard model is commonly used in analysing time-to-event data. However, this model is based on the proportional hazard (PH) assumption. Violation of this assumption …
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The effects of social and spatial density upon attraction, crowding, task performance, and mood
… be different than spatial density, (2) there are time-dependent effects, (3) "crowding" as an intervening variable cannot mediate observed effects of social density, and (4) subjects in the large. group, large room condition showed the greatest number of deleterious effects of treatment. Various …
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Investigation of Concrete Mixtures to Reduce Differential Shrinkage Cracking in Composite Bridges
… bridge deck topping mixture that resists the effects of differential shrinkage by decreasing shrinkage and increasing creep. . In addition, the amount of tensile creep that concrete experiences under long-term tensile stresses were quantified and compared to compressive creep values in order …
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The gravity wave-critical level interaction
… steady state model is used to examine the effects of dissipation. And a nonlinear viscous time dependent model is developed to evaluate the importance of time dependence and nonlinear effects on the development of the gravity wave-critical level interaction. Results obtained with the three …
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Improving Data-Driven Contact Localization and Force Estimation for Barometric Tactile Sensors
… barometric tactile sensor. To allow modeling of time-dependent effects in the sensor material, I introduce a multi-threaded data collection system that captures ground truth contact and sensor data at exactly 100 Hz. I construct both feed-forward and recurrent networks using this data, finding …
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Structural health monitoring of bolted joints using thermal contact resistance and ultrasonic signals
… describing the integrity of bolted joints at the time of assembly. Time-dependent effects of ultrasonic transmitted signals and the SHM feature were studied on the L-shape bolted joints. Experiments showed that time has a significant effect on the ultrasonic signals transmitted through the joint …
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Perching with fixed wings
… will need to reason about the long term and time dependent effects of the unsteady fluid dynamics on the response of the vehicle. Perching is representative of a large class of control problems for aerobatics that requires and agile and robust control system with the capability of planning …
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Nonlinear time-dependent analysis of externally/internally prestressed reinforced concrete beams
… reinforced concrete beams including the time-dependent effects caused by creep and shrinkage of concrete and relaxation of prestressing steel is presented. The procedure is capable of tracing the structural response of these structures through their service load history as well as …
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Investigation of Concrete Mixtures to Reduce Differential Shrinkage Cracking in Inverted T Beam System
… and reduces the likelihood of cracking due to time dependent effects. Differential shrinkage is believed to be one of the causes of deck cracking in inverted T-beam systems. The objective of this study was to develop mix designs that exhibit lower shrinkage and higher creep compared to typical …
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Nonlinear Acoustic Waves Generated by Surface Disturbances and Their Effect on Lower Thermospheric Composition
… often use single gas approximations with height-dependent physical properties (e.g. mean molecular weight, specific heats) that do not vary with time (fixed composition). This approximation is simpler and less computationally expensive than a true multi-fluid model, yet captures the important …
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Effects of GABA on inflammation and intestinal barrier disruption
… (0-48 hrs). Our results showed dose- and time-dependent effects of GABA exposure on monolayer integrity. Exposure of cells to 0.5 – 1 mM, but not higher, of GABA resulted in significant increases in monolayer integrity compared with TNF-α controls and unexposed Caco-2 cells over the first …
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Interacting atoms in time-dependent potentials and artificial gauge fields
… in the simulation of artificial gauge fields via time-modulated tuning of system parameters and via the coupling of internal atomic states by Raman lasers. A second aspect will be the study of systems with synthetic dimensions and the effects of the unconventional infinite range interactions that …
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Temporal interactions with flamingo foraging plasticity: ecological effects on basal resources and benthic heterogeneity
… The specific aim was to test the long-term effects of different foraging structure sizes (which is a subtle form of foraging plasticity) on sedimentary assemblages following foraging disturbances. In situ comparisons of large and small foraging structures created by the flamingos with …
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Long Term Durability of Glass Reinforced Composites
… that post-curing can have significant positive effects on the initial material properties of glass-reinforced vinyl ester composites. Furthermore, the post-cure of 82ºC for four hours stabilizes the matrix, and as such reduces matrix-related material property evolution. By stopping or nearly …
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Global and local performance of prestressed girder bridges with positive moment continuity detail
… positive moment caused by temperature gradients, time dependent effects such as creep and shrinkage, and some live load positions, and on the force transfer mechanisms through the diaphragm. The study utilized different approaches including analytical models for temperature evaluations and finite …
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Analysis of miRNome expression profile in hippocampus of rats treated with antidepressants
… agomelatine. Moreover, in order to assess the time course of ADs effects, treatments were performed for various time lengths (3,7 or 21 days). Rat hippocampal miRNome expression was investigated by means of TaqMan Rodent MicroRNA Arrays. We found that all ADs induced a significant modulation of …
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Continuity of bridges composed of simple-span precast prestressed concrete girders made continuous
… The continuity diaphragms often crack due to time dependent effects in the girders. These cracks not only impair bridge ascetics and durability, but also reduce "degree of continuity". A related issue is that joint construction is time consuming and expensive due to reinforcement congestion. …
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