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

Preauricular sinus: a clinicopathological study

Background: Preauricular sinuses are common congenital malformations. In most instances the diagnosis and management of condition is straightforward.Methods: The present study was done on 26 patients of preauricular sinus who presented to the Department of ENT, S.S. Medical College & G.M. Hospital, Rewa from August 2012 to July 2013 prospectively.Results: Males and females were equally affected. Most patients i.e. 11 belong to 11-20 year age group with age ranging from 4 year to 60 years. Two cases had genetic history and one case was found to be associated with chronic suppurative otitis media (CSOM).Conclusions: The patients in whom a preauricular sinus is identified, the associated congenital anomalies and family history should be sought. Early identification and spreading of awareness should be done to avoid the complication of recurrent abscess in preauricular region

Feasibility of using a high-power electromagnetic energy harvester to power structural health monitoring sensors and systems in transportation infrastructures

This paper investigates the feasibility of an electromagnetism energy harvester (EMEH) for scavenging electric energy from transportation infrastructures and powering of conventional sensors used for their structural health monitoring. The proposed EMEH consists of two stationary layers of three cuboidal permanent magnets (PMs), a rectangular thick aircore copper coil (COIL) attached to the free end of a flexible cantilever beam whose fixed end is firmly attached to the highway bridge oscillating in the vertical motion due to passing traffic. The proposed EMEH utilizes the concept of creating an alternating array of permanent magnets to achieve strong and focused magnetic field in a particular orientation. When the COIL is attached to the cantilever beam and is placed close to the PMs, ambient and traffic induced vibration of the cantilever beam induces eddy current in the COIL. The tip mass and stiffness of the cantilever beam are adjusted such that a low-frequency vibration due to the passing traffic can effectively induce the vibration of the cantilever beam. This vibration is further amplified by tuning the frequency of the cantilever beam and its tip mass to resonance frequency of the highway bridge. The numerical results show that the proposed EMEH is capable of producing an average electrical power more than 1 W at the resonance frequency 4 Hz over a time period of 1 second that alone is more than enough to power conventional wireless sensors

Energy Harvesting for Self-Powered Sensors for Smart Transportation Infrastructures

In this research project, an Electromagnetic Energy Harvesting System (EMEHS) is developed for harvesting the kinetic energy of ambient and traffic-induced vibrations and carry out a detailed feasibility study and impacts of such system for application on transportation infrastructures. The proposed EMEHS utilizes the innovative concept of creating array of large number of small permanent magnets through certain optimization criteria to achieve strong and focused magnetic field in a particular orientation. When these magnets are attached to a flexible sub-system and placed close to the copper coil, ambient and traffic-induced vibration of the sub-system induces eddy current in copper the coil which can be used to power sensors. The mass and stiffness of the sub-system are adjusted such that a low-frequency vibration due to the traffic load can effectively induce the vibration of the sub-system, and thereby increasing the output voltage. This vibration is further amplified by tuning the frequency of the sub-system to resonance condition. The key innovation of the proposed research, as compared to other energy harvesters, is the optimization of array of permanent magnets for achieving a high electric power by developing an accurate analytical model for the magnetic interaction between the permanent magnets and the copper coil in the proposed EMEH. A proof-of-concept prototype of the proposed EMEH has also been designed and fabricated for the laboratory characterization testing, and field testing on a real highway bridge subjected to daily traffic vibration in New York

Geotechnical Damage Due to Bihar Earthquake of August 1988

The Bihar-Nepal earthquake of August 21, 1988 (magnitude 6.6) caused significant loss of life and property. Besides the epicentral area, two distant places (Munger in India and Bhaktapur in Nepal) suffered significantly. This was also the case in the 1934 earthquake (magnitude 8.4) and is due to peculiar geology of the area. Geotechnical damage in the affected area includes liquefaction, cracking and subsidence of embankments, and cracks in bridge abutments and wing walls. Besides, in the hilly regions of Sikkim, landslides and rockfalls disrupted road network significantly. Extensive damage took place in the eastern Nepal also. This paper describes the geotechnical damage to the Indian areas only

Development of An Analytical Method for Design of Electromagnetic Energy Harvesters with Planar Magnetic Arrays

In this paper, an analytical method is proposed for the modeling of electromagnetic energy harvesters (EMEH) with planar arrays of permanent magnets. It is shown that the proposed method can accurately simulate the generation of electrical power in an EMEH from the vibration of a bridge subjected to traffic loading. The EMEH consists of two parallel planar arrays of 5 by 5 small cubic permanent magnets (PMs) that are firmly attached to a solid aluminum base plate, and a thick rectangular copper coil that is connected to the base plate through a set of four springs. The coil can move relative to the two magnetic arrays when the base plate is subjected to an external excitation caused by the vehicles passing over the bridge. The proposed analytical model is used to formulize the magnetic interaction between the magnetic arrays and the moving coil and the electromechanical coupling between both the electrical and mechanical domains of the EMEH. A finite element model is developed to verify the accuracy of the proposed analytical model to compute the magnetic force acting on the coil. The analytical model is then used to conduct a parametric study on the magnetic arrays to optimize the arrangement of the PM poles, thereby maximize the electrical power outputted from the EMEH. The results of parametric analysis using the proposed analytical method show that the EMEH, under the resonant condition, can deliver an average electrical power as large as 500 mW when the PM poles are arranged alternately along the direction of vibration for a peak base acceleration of 0.1 g. A proof-of-concept prototype of the EMEH is fabricated to test its performance for a given arrangement of PMs subjected to vibration in both the lab and field environments. View Full-Tex

Forebody Wake Effects on Parachute Performance for Re entry Space Application

Forebody generates its own wake that influences the performance of aerodynamic decelerators during the flights. Many parachute Jumpers have experienced the failure of an ejected pilot chute as the parachute canopy collapsed and fell back on the Jumper because of wake developed behind the Jumper. In the available literature, limited data is available to predict the exact loss of parachute drag in presence of the forebody (FB). The purpose of this paper is to generate a comprehensive aerodynamic data to study the behaviour of FB-parachute dynamics by conducting the wind tunnel experiments. Wind tunnel test has been carried out to establish the initial design parameters of aerodynamic parachute. The experiment was carried out on a scale down model of 20 degree conical ribbon drogue parachute and FB with and without each of them at a subsonic speed for studying dynamic stability characteristic for different orientation of FB. The test results indicate that to ensure adequate stability for the capsule to descend vertically at a low subsonic speed, a cluster of two drogue parachutes be used. Under such condition, the overall drag coefficient found to be above 0.50 providing not only a safe descends velocity but increasing reliability of mission as well

Transcriptional analysis of an immune-responsive serine protease from Indian malarial vector, Anopheles culicifacies

<p>Abstract</p> <p>Background</p> <p>The main vector for transmission of malaria in India is the <it>Anopheles culicifacies </it>mosquito species, a naturally selected subgroup of which is completely refractory (R) to transmission of the malaria parasite, <it>Plasmodium vivax</it>;</p> <p>Results</p> <p>Here, we report the molecular characterization of a serine protease (<it>acsp30</it>)-encoding gene from <it>A. culicifacies</it>, which was expressed in high abundance in the refractory strain compared to the susceptible (S) strain. The transcriptional upregulation of <it>acsp30 </it>upon <it>Plasmodium </it>challenge in the refractory strain coincided with ookinete invasion of mosquito midgut. Gene organization and primary sequence of <it>acsp30 </it>were identical in the R and S strains suggesting a divergent regulatory status of <it>acsp30 </it>in these strains. To examine this further, the upstream regulatory sequences of <it>acsp30 </it>were isolated, cloned and evaluated for the presence of promoter activity. The 702 bp upstream region of <it>acsp30 </it>from the two strains revealed sequence divergence. The promoter activity measured by luciferase-based reporter assay was shown to be 1.5-fold higher in the R strain than in the S. Gel shift experiments demonstrated a differential recruitment of nuclear proteins to upstream sequences of <it>acsp30 </it>as well as a difference in the composition of nuclear proteins in the two strains, both of which might contribute to the relative abundance of <it>acsp30 </it>in the R strain;</p> <p>Conclusion</p> <p>The specific upregulation of <it>acsp30 </it>in the R strain only in response to <it>Plasmodium </it>infection is suggestive of its role in contributing the refractory phenotype to the <it>A. culicifacies </it>mosquito population.</p

Reliability and Network Performance Enhancement by Reconfiguring Underground Distribution Systems

Contemporary distributions are now going to underground their overhead distribution lines due to techno-social reasons. Reliability and loss reduction are the two prime objectives for distribution system operation. Since failure rates of ungrounded cables are the function of Joules heating besides their physical lengths, the reliability evaluation of undergrounded distribution systems needs to be reviewed. This paper suggested a suitable modification in existing reliability indices in order to make them more appropriate for underground distribution systems. A multi-objective network reconfiguration problem is formulated to enhance the reliability and performance of distribution systems while duly addressing the variability and uncertainty in load demand and power generation from renewables. The application results on a standard test bench shift the paradigm of the well-known conflicting nature of reliability and network performance indices defined for overhead distribution systems