Fatigue Crack Detection Using Unmanned Aerial Systems in Under-Bridge Inspection

The applications of Unmanned Aerial Systems (UAS) for bridge inspection, with emphasis on under-bridge inspection and fatigue crack detection, were studied in this report. The potential benefits and challenges of using UAS for bridge inspection were identified through an extensive literature survey. The feasibility of using UAS for fatigue crack detection was studied by determining the minimum lighting, camera distance and environmental requirements for three UAS. The DJI Mavic UAS performed better than the others in both indoor and outdoor GPS-denied inspections. An in-service bridge in Ashton, Idaho was inspected using this UAS to find fatigue cracks. No fatigue crack, known or new, was detected in the UAS images but marker lines around the known fatigue cracks (drawn by the inspectors in previous inspections), concrete defects, and steel rust were detected. Thermography showed promising results for fatigue crack detection in a lab setting, but it was not feasible for UAS applications since it had to be performed using active thermography techniques to obtain adequate results. Additionally, image processing algorithms for autonomous detection of both concrete and fatigue cracks were successfully developed. These algorithms, especially for fatigue crack detection, require more images to perform better, but were demonstrated as feasible to aid in a real-time inspection

Modeling a Helical-coil Steam Generator in RELAP5-3D for the Next Generation Nuclear Plant

Options for the primary heat transport loop heat exchangers for the Next Generation Nuclear Plant are currently being evaluated. A helical-coil steam generator is one heat exchanger design under consideration. Safety is an integral part of the helical-coil steam generator evaluation. Transient analysis plays a key role in evaluation of the steam generators safety. Using RELAP5-3D to model the helical-coil steam generator, a loss of pressure in the primary side of the steam generator is simulated. This report details the development of the steam generator model, the loss of pressure transient, and the response of the steam generator primary and secondary systems to the loss of primary pressure. Back ground on High Temperature Gas-cooled reactors, steam generators, the Next Generation Nuclear Plant is provided to increase the readers understanding of the material presented

The Changing Landscape for Stroke\ua0Prevention in AF: Findings From the GLORIA-AF Registry Phase 2

Background GLORIA-AF (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation) is a prospective, global registry program describing antithrombotic treatment patterns in patients with newly diagnosed nonvalvular atrial fibrillation at risk of stroke. Phase 2 began when dabigatran, the first non\u2013vitamin K antagonist oral anticoagulant (NOAC), became available. Objectives This study sought to describe phase 2 baseline data and compare these with the pre-NOAC era collected during phase 1. Methods During phase 2, 15,641 consenting patients were enrolled (November 2011 to December 2014); 15,092 were eligible. This pre-specified cross-sectional analysis describes eligible patients\u2019 baseline characteristics. Atrial fibrillation disease characteristics, medical outcomes, and concomitant diseases and medications were collected. Data were analyzed using descriptive statistics. Results Of the total patients, 45.5% were female; median age was 71 (interquartile range: 64, 78) years. Patients were from Europe (47.1%), North America (22.5%), Asia (20.3%), Latin America (6.0%), and the Middle East/Africa (4.0%). Most had high stroke risk (CHA2DS2-VASc [Congestive heart failure, Hypertension, Age  6575 years, Diabetes mellitus, previous Stroke, Vascular disease, Age 65 to 74 years, Sex category] score  652; 86.1%); 13.9% had moderate risk (CHA2DS2-VASc = 1). Overall, 79.9% received oral anticoagulants, of whom 47.6% received NOAC and 32.3% vitamin K antagonists (VKA); 12.1% received antiplatelet agents; 7.8% received no antithrombotic treatment. For comparison, the proportion of phase 1 patients (of N = 1,063 all eligible) prescribed VKA was 32.8%, acetylsalicylic acid 41.7%, and no therapy 20.2%. In Europe in phase 2, treatment with NOAC was more common than VKA (52.3% and 37.8%, respectively); 6.0% of patients received antiplatelet treatment; and 3.8% received no antithrombotic treatment. In North America, 52.1%, 26.2%, and 14.0% of patients received NOAC, VKA, and antiplatelet drugs, respectively; 7.5% received no antithrombotic treatment. NOAC use was less common in Asia (27.7%), where 27.5% of patients received VKA, 25.0% antiplatelet drugs, and 19.8% no antithrombotic treatment. Conclusions The baseline data from GLORIA-AF phase 2 demonstrate that in newly diagnosed nonvalvular atrial fibrillation patients, NOAC have been highly adopted into practice, becoming more frequently prescribed than VKA in Europe and North America. Worldwide, however, a large proportion of patients remain undertreated, particularly in Asia and North America. (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients With Atrial Fibrillation [GLORIA-AF]; NCT01468701

System Identification of a Small Low-Cost Unmanned Aerial Vehicle Using Flight Data from Low-Cost Sensors

Remote sensing has traditionally been done with satellites and manned aircraft. While these methods can yield useful scientific data, satellites and manned aircraft have limitations in data frequency, process time, and real time re-tasking. Small low-cost unmanned aerial vehicles (UAVs) provide greater possibilities for personal scientific research than traditional remote sensing platforms. Precision aerial data requires an accurate vehicle dynamics model for controller development, robust flight characteristics, and fault tolerance. One method of developing a model is system identification (system ID). In this thesis system ID of a small low-cost fixed-wing T-tail UAV is conducted. The linerized longitudinal equations of motion are derived from first principles. Foundations of Recursive Least Squares (RLS) are presented along with RLS with an Error Filtering Online Learning scheme (EFOL). Sensors, data collection, data consistency checking, and data processing are described. Batch least squares (BLS) and BLS with EFOL are used to identify aerodynamic coefficients of the UAV. Results of these two methods with flight data are discussed

Software-and hardware-in-the-loop verification of flight dynamics model and flight control simulation of a fixed-wing unmanned aerial vehicle

Unmanned aerial system (UAS) use is ever-increasing. In this paper, it is shown that even with low-cost hardware and open-source software, simple numerical testing practices (software- and hardware-in-the-loop) can prove the accuracy and usefulness of an aeronautical flight model, as well as provide valuable pre-flight testing of many situations typically only encountered in flight: high winds, hardware failure, etc. Software and hardware simulation results are compared with actual flight testing results to show that these modeling and testing techniques are accurate and provide a useful testing platform for a small unmanned aerial vehicle. Source code used in simulation is open and provided to the community

An open-source real-time UAS flight control prototyping and testing platform with fractional-order horizontal controller example

Safety and reliability are key if unmanned aerial systems (UAS) are to move from research and become an everyday part of our lives. How can safety and reliability be maintained when cost and timeliness are such pressing factors in small UAS development? In this paper, it is shown that with open-source flight control software (provided by the authors), sophisticated testing practices (hardware-in-the-loop) can provide rapid pre-flight verification of experimental control system designs. Using these methods increases the reliability of flight control software developed in many ways if tested properly Both PID and auto-generated PIλD control schemes are compared as examples of flight software under test, and simulated flight performance is shown

Improving communication security of open source UAVs: Encrypting radio control link

Safety and reliability (also referred to as airworthiness) are well-known factors of Unmanned Aerial Vehicle (UAV) operations, and significant effort has been put into maintaining and improving them for everyday UAV users. Cyber-security, on the other hand, gained attention only recently. Currently, a malicious user can relatively easily disturb operation or even seize control of the most popular open-source UAVs, as a result of their poor communications security (COMSEC). Even though solutions to improve UAV\u27s COMSEC are known, they have not been fully implemented in a user-friendly way. The contribution of the paper is an implementation of an encrypted Radio Control (RC) link that can be used with a number of popular RC transmitters. We use Galois Embedded Crypto library, an ArduinoLibs Crypto library together with openLRSng open-source radio project. We provide some lessons learned during development, implementation, and testing so users wishing to use their own encrypted link can leverage our work

Development and Transient Analysis of a Helical-coil Steam Generator for High Temperature Reactors

A high temperature gas-cooled reactor (HTGR) is under development by the Next Generation Nuclear Plant (NGNP) Project at the Idaho National Laboratory (INL). Its design emphasizes electrical power production which may potentially be coupled with process heat for hydrogen production and other industrial applications. NGNP is considering a helical-coil steam generator for the primary heat transport loop heat exchanger based on its increased heat transfer and compactness when compared to other steam generators. The safety and reliability of the helical-coil steam generator is currently under evaluation as part of the development of NGNP. Transients, such as loss of coolant accidents (LOCA), are of interest in evaluating the safety of steam generators. In this study, a complete steam generator inlet pipe break (double ended pipe break) LOCA was simulated by an exponential loss of primary side pressure. For this analysis, a model of the helical-coil steam generator was developed using RELAP5-3D, an INL in-house systems analysis code. The steam generator model behaved normally during the transient simulating the complete steam generator inlet pipe break LOCA. Further analysis is required to comprehensively evaluate the safety and reliability of the helical-coil steam generator design in the NGNP setting

Modeling a Helical-coil Steam Generator in RELAP5- 3D for the Next Generation Nuclear Plant

Options for the primary heat transport loop heat exchangers for the Next Generation Nuclear Plant (NGNP) are currently being evaluated. A helical-coil steam generator is one heat-exchanger design under consideration. Helical-coil steam generators are preferred over other steam generators for their increased heat transfer and compactness. Safety and reliability are an integral part of the helical-coil steam generator evaluation for NGNP. Transient analysis plays a key role in evaluating the safety of steam generators. Operational transients, such as start up, shut down, and loss of coolant accidents, are transients of interest. The helical-coil steam generator is modeled using RELAP5-3D, an Idaho National Laboratory in-house code. The transient response of an exponential loss of pressure (simulating double-ended shear) in the primary side of the steam generator is simulated. The exponential loss of pressure models a break of the steam generator inlet pipe. This report details the development of the helical-coil steam generator model and the loss of pressure transient. Background on high temperature gas-cooled reactors and steam generators is provided to aid the reader in understanding the material presented. A detailed description of the RELAP5-3D helical-coil steam generator model is presented. An explanation is given of each of the RELAP5- 3D components used in modeling the steam generator. Also reported is the response of the steam generator primary and secondary systems to the exponential loss of primary pressure