Quantitative Bridge Inspection Ratings Using Autonomous Robotic Systems

The 2001 study sponsored by FHWA raised serious concern on the consistency and reliability of visual inspection. Although consistent ratings can be obtained with a good QA/QC program, based on a recent study by the PI, the concern for reliability of defect detection remains. With the adoption of the recent AASHTO Manuel for Bridge Element Inspection, the new inspection approach not only requires rating for bridge elements, but also the location and extent of deterioration. Since autonomous robotic systems generate an enormous amount of inspection data, deducing from the data to a simple rating along with the location and extent of deterioration is a significant challenge. For example, RABITTM has been used to inspect concrete bridge decks with six devices, including ground penetrating radar (GPR), impact-echo and ultrasonic surface wave. However, the probability of detection (POD) for damage has not been fully demonstrated to be significantly improved using multiple devices. This project aims to develop new fusion strategies of data collected from multiple NDE devices for improved POD based on further understanding and modeling of damage detection mechanisms, and to develop algorithms for the derivation of bridge ratings from identified damage and visual inspection findings

Performance Based Design for Bridge Piers Impacted by Heavy Trucks

Based on bridge failure data compiled by New York State Department of Transportation, collision, both caused by vessel and vehicles, is the second leading cause of bridge failures after hydraulic. Current AASHTO-LRFD (2012) recommends designing a bridge pier vulnerable to vehicular impacts for an equivalent static force of 600 kips (2,670 kN) applied in a horizontal plane at a distance of 5.0 feet above the ground level. This research presents a performance-based approach for designing a bridge pier subject to impacts by tractor-semi-trailer weighing up to 80,000 lb based on an extensive investigation using finite element model of a tractor-semitrailer in LS-DYNA. In order to ensure the reliability of the proposed approach, parameters of concrete model were calibrated using small-scale impact test and were validated using a large scale test. Mechanics and modes of failure of bridge pier bents during vehicular impacts were verified through pendulum impact test on a large scale model of three column pier-bent system. A performance-based approach in terms of shear distortion, plastic rotation and demand / capacity (D/C) ratio has been proposed for the design of bridge piers vulnerable to heavy vehicle impacts

Quantitative Bridge Inspection Ratings Using Autonomous Robotic Systems

Impact sounding has been recognized as an effective technique to detect delamination in concrete structures, such as concrete decks. An enormous amount of sounding data can be generated/collected by the autonomous inspection systems equipped with impactors and microphones. However, the main challenge in the practical application of this technology is the development of advanced data analysis approaches for identifying defects from impact sounding data. In this study, the empirical mode decomposition (EMD) analysis and power-spectral density (PSD) analysis are combined to extract useful features of sounding data generated by the impact hammer. It has been found that the EMD method can effectively eliminate noise from the captured data during the identification of features such as the fundamental frequency. Based on extracted features, a defect contour of the inspected structure can be generated for fast decision making and reliable inspection ratings of concrete structures

Intrauterine retention of fetal bones, a cause for secondary infertility

Secondary infertility due to retained products of conception in the form of fetal bones is a rare entity. It is usually associated with a history of abortion, either spontaneous or induced. The bony fragments probably act as an intrauterine contraceptive device to stimulate the secretion of endometrial prostaglandins, resulting in secondary infertility. The common symptoms include menstrual disturbances, pelvic pain, dyspareunia, vaginal discharge, spontaneous passage of fetal bones and infertility. Advanced diagnostic technique like hysteroscopy has helped in the diagnosis

Arteriovenous malformation of external ear and temporal region: a case report

Arteriovenous malformations (AVMs) of the scalp are remarkably rare. We report a case of 20 years old female complaining of swelling over right pinna and scalp since 2 years with known history of trauma. This case report represents pathogenesis, clinical features and management of the disease

A Modeling System for Integral Simulation of Propagation of Ocean Surge and Wave and Their Impinging on Coastal Structure (Extended Abstract)

Now it has become necessary to develop our capability to directly simulate many emerging coastal ocean flow and wave problems. These flow problems present a common challenge to our modeling capability; they involve multiphysics phenomena spanning a vast range of spatial and temporal scales, however, so far essentially we have no methods and computer software to directly and integrally simulate these phenomena. Now it has become necessary for us to develop new capability to model them in efficient ways and high-fidelity. Towards this goal, we have developed a brand new, unprecedented modeling system that is able to directly evaluate many emerging multiscale, multiphysics flow problems. In this presentation, the newly developed modeling system will be introduced, together with numerical experiments and applications

Can Ethical Leaders Enhance Knowledge Sharing? The Role of Psychological Capital and Anticipated Reciprocal Relationships

The aim of the paper is to empirically investigate the influence of ethical leadership and psychological capital on knowledge sharing in business organizations. Furthermore, the paper investigates the mediating role of psychological capital and moderating role of anticipated reciprocal relationships in the relationship of ethical leadership with knowledge sharing. The analysis has been conducted on data gathered from 248 members of information technology (IT) companies by making use of survey questionnaire. Hypotheses are tested by analysing the data using structural equation modelling (SEM) and PROCESS macro. The study found that ethical leadership and psychological capital have positive effect on knowledge sharing. Ethical leadership also impacts psychological capital positively. Further, psychological capital acts as a mediator and anticipated reciprocal relationships act as moderator in the relationship of ethical leadership and knowledge sharing. This study establishes new antecedents of knowledge sharing, emphasizes the importance of ethical aspects of leadership in managing knowledge resources and enrich literature of Knowledge Management (KM), leadership, positive organizational behavior and human resources management. It further gives new perspectives to practitioners by recognizing the significance of ethical leadership, psychological capital and anticipated reciprocal relationships to enhance knowledge sharing. To the best of authors’ knowledge, this study is one of few initial studies to examine the linkages between ethical leadership, knowledge sharing and psychological capital as well as the role of anticipated reciprocal relationships therein

Design and Performance Analysis of a Rectangular Microstrip Patch Antenna for Wireless Communication at 2.4 GHz

This paper presents the design of a rectangular Microstrip Patch Antenna (MPA) intended for operation at 2.4 GHz frequency, predominantly used in wireless communication. The proposed MPA, designed on an FR4-Epoxy substrate using a microstrip line feeding approach, was simulated using the High-Frequency Structure Simulator (HFSS). The primary metrics evaluated included return loss, gain, Voltage Standing Wave Ratio (VSWR), and half-power beamwidth. The findings revealed an impressive return loss of -25dB and a moderate gain of 1.48 dB at the target frequency. The VSWR value was approximately 1, indicating efficient power transmission with minimal reflections. Furthermore, the antenna exhibited a broad half-power beamwidth of 79 degrees, suggesting its potential for applications requiring extensive signal coverage. This research provides insights into MPA design principles and serves as a foundation for future advancements in wireless communication antenna systems

The Influence of High-Energy Lithium Ion Irradiation on Electrical Characteristics of Silicon and GaAs Solar Cells

Space-grade Si and GaAs solar cells were irradiated with 15 & 40 MeV Li ions. Illuminated (AM0 condition) and unilluminated I-V curves reveal that the effect of high-energy Li ion irradiation has produced similar effects to that of proton irradiation. However, an additional, and different, defect mechanism is suggested to dominate in the heavier-ion results. Comparison is made with proton-irradiated solar-cell work and with non-ionizing energy-loss (NIEL) radiation-damage models.Comment: 8 pages, 12 figures, Data presented at 2006 NSREC, Final Version to be published in IEEE Transactions on Nuclear Science, 53, NO. 6, December 2006. Index Terms: GaAs, Ion-irradiation, Lithium, NIEL, Photovoltaic cells, Radiation effects, Silico