Synthetic aperture guided wave imaging using a mobile sensor platform

This oral session at conference looks at synthetic aperture guided wave imaging using a mobile sensor platfor

A noncontact ultrasonic platform for structural inspection

Miniature robotic vehicles are receiving increasing attention for use in nondestructive testing (NDE) due to their attractiveness in terms of cost, safety, and their accessibility to areas where manual inspection is not practical. Conventional ultrasonic inspection requires the provision of a suitable coupling liquid between the probe and the structure under test. This necessitates either an on board reservoir or umbilical providing a constant flow of coupling fluid, neither of which are practical for a fleet of miniature robotic inspection vehicles. Air-coupled ultrasound offers the possibility of couplant-free ultrasonic inspection. This paper describes the sensing methodology, hardware platform and algorithms used to integrate an air-coupled ultrasonic inspection payload into a miniature robotic vehicle platform. The work takes account of the robot's inherent positional uncertainty when constructing an image of the test specimen from aggregated sensor measurements. This paper concludes with the results of an automatic inspection of a aluminium sample

Integrating Agroforestry Practices for Wildlife Habitat (2008)

"Agricultural practices and land-use decisions influence wildlife habitat and use by wildlife. Some actions can enhance habitats, while others negatively impact wildlife. Certain land-use practices have resulted in a decrease in the quality and diversity of available wildlife habitat on the farm. For example, more efficient farming practices, larger field sizes and the loss of field borders, such as those provided by windbreaks and brushy fence rows, have generally had a negative impact on habitat."--First page.by Dusty Walter (Technology Transfer Specialist, University of Missouri Center for Agroforestry), and Robert A. Pierce II (MU Extension Fisheries and Wildlife Specialist

Integrating agroforestry practices for wildlife habitat

"Agricultural practices and land-use decisions influence wildlife habitat and use by wildlife. Some actions can enhance habitats, while others negatively impact wildlife. Certain land-use practices have resulted in a decrease in the quality and diversity of available wildlife habitat on the farm. For example, more efficient farming practices, larger field sizes and the loss of field borders, such as those provided by windbreaks and brushy fence rows, have generally had a negative impact on habitat. Agroforestry practices can be used to provide many benefits to a farm, such as improved water quality, soil stabilization and income opportunities. Agroforestry also can be used to provide diversity to a farm and enhance the potential to provide habitat for a variety of wildlife species."--Page 1.Authors: Dusty Walter (Director, Natural Resources Management and Director, Central Missouri Research, Extension and Education Center), Robert A. Pierce II (Associate Extension Professor and State Fisheries and Wildlife Specialist)New '08; Revised 11/2

Simulation of ultrasonic lamb wave generation, propagation and detection for an air coupled robotic scanner

A computer simulator, to facilitate the design and assessment of a reconfigurable, air-coupled ultrasonic scanner is described and evaluated. The specific scanning system comprises a team of remote sensing agents, in the form of miniature robotic platforms that can reposition non-contact Lamb wave transducers over a plate type of structure, for the purpose of non-destructive evaluation (NDE). The overall objective is to implement reconfigurable array scanning, where transmission and reception are facilitated by different sensing agents which can be organised in a variety of pulse-echo and pitch-catch configurations, with guided waves used to generate data in the form of 2-D and 3-D images. The ability to reconfigure the scanner adaptively requires an understanding of the ultrasonic wave generation, its propagation and interaction with potential defects and boundaries. Transducer behaviour has been simulated using a linear systems approximation, with wave propagation in the structure modelled using the local interaction simulation approach (LISA). Integration of the linear systems and LISA approaches are validated for use in Lamb wave scanning by comparison with both analytic techniques and more computationally intensive commercial finite element/difference codes. Starting with fundamental dispersion data, the paper goes on to describe the simulation of wave propagation and the subsequent interaction with artificial defects and plate boundaries, before presenting a theoretical image obtained from a team of sensing agents based on the current generation of sensors and instrumentation

The German Officer Corps and the Socialists, 1918-1920: A Reappraisal

This work attempts to examine the relationship shared by two ideologically opposed groups during the post-World War I period in Germany. The officer corps is viewed as a relic of the traditional imperial state while the socialists represented the harbinger of the modern, democratic, industrialized state. Although it should seem evident that these two factions of society would be natural enemies, the chaos of World War I pushed these ideological, opposites into the same corner

Herr und Heer: the German Social Democrats and officer corps, a reappraisal

Utilizing the debates of the German Reichstag, the proceedings of the SPD, the memoirs of the leading military and Marxist figures and the principal newspapers of the Second Reich and Weimar Republic, this dissertation attempts to show how the army chiefs and the socialist leaders of Germany altered their policies not only to promote their interests but also to protect the state

Noninvasive imaging of focal atherosclerotic lesions using fluorescence molecular tomography

Insights into the etiology of stroke and myocardial infarction suggest that rupture of unstable atherosclerotic plaque is the precipitating event. Clinicians lack tools to detect lesion instability early enough to intervene, and are often left to manage patients empirically, or worse, after plaque rupture. Noninvasive imaging of the molecular events signaling prerupture plaque progression has the potential to reduce the morbidity and mortality associated with myocardial infarction and stroke by allowing early intervention. Here, we demonstrate proof-of-principle in vivo molecular imaging of C-type natriuretic peptide receptor in focal atherosclerotic lesions in the femoral arteries of New Zealand white rabbits using a custom built fiber-based, fluorescence molecular tomography (FMT) system. Longitudinal imaging showed changes in the fluorescence signal intensity as the plaque progressed in the air-desiccated vessel compared to the uninjured vessel, which was validated by ex vivo tissue studies. In summary, we demonstrate the potential of FMT for noninvasive detection of molecular events leading to unstable lesions heralding plaque rupture

Integration of acoustic emission systems within Integri-Tech™ analysis system for structural health monitoring of pressurised engineering plant

The aim of this Acoustic Emission (AE) based Structural Health Monitoring project is to enable accurate location of AE sources in pressurised engineering plant and to use AE source location data to establish defect locations for use within Integri-Tech™; a finite element based analysis, monitoring and fitness for service assessment system. Integri-Tech™ is a windows based system which carries out combined analysis and assessment providing fatigue life and remnant life calculations and inspection priorities presenting the results in an accessible web portal format. The software uses finite element stress models created in the companion software Model Wizard. The AE monitoring system that has been developed can be used with an array of up to four AE broad band sensor channels with associated signal processing. Using a flexible approach in MATLAB, the authors have developed algorithms which were used for analysing the received AE signals to extract information about the nature and location of the source. The ability to carry out source location and possibly perform real time monitoring (detecting cracking as it occurs) is attractive feature of the AE system developed for this project. The time of arrival (TOA) data was used by Integri-Tech™ software to calculate source location using its own built-in algorithm, and this was verified independently using a MATLAB approach

Confidence Testing of Shell 405 and S-405 Catalysts in a Monopropellant Hydrazine Thruster

As part of the transfer of catalyst manufacturing technology from Shell Chemical Company (Shell 405 catalyst manufactured in Houston, Texas) to Aerojet (S-405 manufactured in Redmond, Washington), Aerojet demonstrated the equivalence of S-405 and Shell 405 at beginning of life. Some US aerospace users expressed a desire to conduct a preliminary confidence test to assess end-of-life characteristics for S-405. NASA Marshall Space Flight Center (MSFC) and Aerojet entered a contractual agreement in 2004 to conduct a confidence test using a pair of 0.2-lbf MR-103G monopropellant hydrazine thrusters, comparing S-405 and Shell 405 side by side. This paper summarizes the formulation of this test program, explains the test matrix, describes the progress of the test, and analyzes the test results. This paper also includes a discussion of the limitations of this test and the ramifications of the test results for assessing the need for future qualification testing in particular hydrazine thruster applications