Mobile gamma Spectrometry Measurements of Coneyside Beach, Cumbria

<p>Environmental radioactivity arises from natural and anthropogenic sources: 238U, 232Th and their decay products, and 40K in differing concentrations in rocks and soils; natural materials transformed by industrial processes to enhance the concentrations of some radioactive isotopes; materials discharged from some nuclear processes; fallout from nuclear accidents and weapons testing; radioactive sources that may have been lost or stolen; and radiation shine from sites using nuclear technology. Mobile gamma spectrometry provides powerful methods of measuring the distribution of radioactivity in the environment; airborne platforms allow the rapid survey of large areas, and ground based platforms more detailed surveys of smaller areas.</p> <p>Airborne surveys in 1990 (conducted to produce a baseline data set for the Sellafield site) and 2000 (as part of a large study on spatial and temporal aspects of airborne measurements) showed several radiometric features along the coast, including elevated 137Cs activity along a beach in West Cumbria between St Bees and Nethertown, in an environment comprising pebbles and gravel where this was unexpected. An additional short survey of this area was conducted during the 2000 survey, at reduced ground clearance and speed, to verify the existence of these unexpected signals. With increased interest in the search and recovery of particulate activity from the beaches in the vicinity of Sellafield, this data was reviewed in 2008 to illustrate the use of airborne methods in locating potential particulate activity on beaches and to aid in the planning of further ground based investigations. SUERC conducted an exploratory ground based survey in June 2010; to investigate whether the features observed in the airborne surveys were still present, to define the spatial distribution of activity more precisely, and to attempt to assess the form of the activity and whether it had been redistributed since 2000. This report presents the 2000 airborne measurements reviewed in 2008, with the results of the June 2010 survey.</p> <p>A portable gamma spectrometry system has been developed at SUERC. This consists of a 3x3” NaI(Tl) detector with digital spectrometer, a GPS receiver and netbook computer. The system is lightweight, easy to use and can be carried over terrain that would be inaccessible to vehicular systems. By holding the detector close to the ground the extent of any observed enhanced activity feature can be determined more precisely. Two of these systems have been field tested on the 22-23rd June 2010 along this beach.</p> <p>The exploratory survey has clearly demonstrated the utility of the SUERC backpack system in producing detailed maps of the distribution of radioactive materials in the environment. A survey using two systems successfully mapped an area of approximately 50x200m with very high density measurements in a period of approximately 2h.</p> <p>It has shown that the enhanced 137Cs activity is still present on the beach, in locations that are consistent with the earlier airborne measurements. The more detailed survey shows a pattern of patches of enhanced 137Cs activity. Samples collected from some of these had concentrations of 50 Bq kg-1, which would account for the observed 137Cs count rate. The nature of the material that carries this activity is at present unknown.</p&gt

Design of a TMS320 C25 signal processor for use in a monopulse radar

Summary in English.Charts in pocket.Bibliography: leaf 65.The advent of better and faster digital signal processing chips has led to digital implementation of many functions that have previously only been possible using analogue techniques. One such field is monopulse radar where available processing time is limited strictly to the radar pulse repetition frequency. The aim of this thesis is to design a specific signal processor using a Texas Instruments TMS320 C25 processor. This design is intended for monopulse radar systems using low pulse repetition frequencies. Features typical to monopulse radar signal processing, have been described here as system requirements. From this description a system specification, which is in fact the functional design of the processor, has been developed. Prototype circuitry was then designed and built in order to test the feasibility of performing, within the required time, the functions outlined in the system specification. Following on from the results of the tests, design of the hardware commenced. The design was successfully completed and tested. Although the TMS320 C25 was not found to be the ideal processor for this application, it is capable of performing the task within the required time. Careful consideration was given to the software design. A trade off between easily maintainable, high level language software, and high speed assembler had to be made. The final product is written in c but with critical procedures implemented in in-line assembler. This thesis provides insight into the type of hardware and the level of signal processing required for one type of signal processor used in a low PRF monopulse system

Nonlinear observers for predicting state-of-charge and state-of-health of lead-acid batteries for hybrid-electric vehicles

Abstract—This paper describes the application of state-estimation techniques for the real-time prediction of the state-of-charge (SoC) and state-of-health (SoH) of lead-acid cells. Specifically, approaches based on the well-known Kalman Filter (KF) and Extended Kalman Filter (EKF), are presented, using a generic cell model, to provide correction for offset, drift, and long-term state divergence—an unfortunate feature of more traditional coulomb-counting techniques. The underlying dynamic behavior of each cell is modeled using two capacitors (bulk and surface) and three resistors (terminal, surface, and end), from which the SoC is determined from the voltage present on the bulk capacitor. Although the structure of the model has been previously reported for describing the characteristics of lithium-ion cells, here it is shown to also provide an alternative to commonly employed models of lead-acid cells when used in conjunction with a KF to estimate SoC and an EKF to predict state-of-health (SoH). Measurements using real-time road data are used to compare the performance of conventional integration-based methods for estimating SoC with those predicted from the presented state estimation schemes. Results show that the proposed methodologies are superior to more traditional techniques, with accuracy in determining the SoC within 2% being demonstrated. Moreover, by accounting for the nonlinearities present within the dynamic cell model, the application of an EKF is shown to provide verifiable indications of SoH of the cell pack

Observer techniques for estimating the state-of-charge and state-of-health of VRLABs for hybrid electric vehicles

The paper describes the application of observer-based state-estimation techniques for the real-time prediction of state-of-charge (SoC) and state-of-health (SoH) of lead-acid cells. Specifically, an approach based on the well-known Kalman filter, is employed, to estimate SoC, and the subsequent use of the EKF to accommodate model non-linearities to predict battery SoH. The underlying dynamic behaviour of each cell is based on a generic Randles' equivalent circuit comprising of two-capacitors (bulk and surface) and three resistors, (terminal, transfer and self-discharging). The presented techniques are shown to correct for offset, drift and long-term state divergence-an unfortunate feature of employing stand-alone models and more traditional coulomb-counting techniques. Measurements using real-time road data are used to compare the performance of conventional integration-based methods for estimating SoC, with those predicted from the presented state estimation schemes. Results show that the proposed methodologies are superior with SoC being estimated to be within 1% of measured. Moreover, by accounting for the nonlinearities present within the dynamic cell model, the application of an EKF is shown to provide verifiable indications of SoH of the cell pack

Operation of three-level inverter-based shunt active power filter under nonideal grid voltage conditions with dual fundamental component extraction

In this paper, a new reference current generation method is proposed for effective harmonics mitigation and reactive power compensation of three-level neutral-point diode clamped inverter-based shunt active power filter (SAPF) under nonideal grid voltage conditions. The proposed method is named as dual fundamental component extraction algorithm. In operation, the proposed algorithm extracts at the same time, the desired fundamental current and voltage components for generating reference current and synchronization phases, respectively. As a result, the proposed algorithm is able to generate reference current that ensures in phase operation of SAPF with the operating power system, without depending on any phase-locked loop elements. Besides, the proposed algorithm employs self-tuning filter (STF) for accurate computation of the fundamental components. Design concept and effectiveness of the proposed algorithm are thoroughly studied and evaluated in MATLAB-Simulink. Additionally, a laboratory prototype utilizing TMS320F28335 digital signal processor is built to validate its feasibility. Encouraging findings obtained from both simulation and experimental works demonstrate effectiveness of the proposed algorithm under both ideal and nonideal grid voltage conditions

A brief network analysis of Artificial Intelligence publication

In this paper, we present an illustration to the history of Artificial Intelligence(AI) with a statistical analysis of publish since 1940. We collected and mined through the IEEE publish data base to analysis the geological and chronological variance of the activeness of research in AI. The connections between different institutes are showed. The result shows that the leading community of AI research are mainly in the USA, China, the Europe and Japan. The key institutes, authors and the research hotspots are revealed. It is found that the research institutes in the fields like Data Mining, Computer Vision, Pattern Recognition and some other fields of Machine Learning are quite consistent, implying a strong interaction between the community of each field. It is also showed that the research of Electronic Engineering and Industrial or Commercial applications are very active in California. Japan is also publishing a lot of papers in robotics. Due to the limitation of data source, the result might be overly influenced by the number of published articles, which is to our best improved by applying network keynode analysis on the research community instead of merely count the number of publish.Comment: 18 pages, 7 figure

Technical aspects of a demonstration tape for three-dimensional sound displays

This document was developed to accompany an audio cassette that demonstrates work in three-dimensional auditory displays, developed at the Ames Research Center Aerospace Human Factors Division. It provides a text version of the audio material, and covers the theoretical and technical issues of spatial auditory displays in greater depth than on the cassette. The technical procedures used in the production of the audio demonstration are documented, including the methods for simulating rotorcraft radio communication, synthesizing auditory icons, and using the Convolvotron, a real-time spatialization device

Compact, High Energy 2-micron Coherent Doppler Wind Lidar Development for NASA's Future 3-D Winds Measurement from Space

This paper presents an overview of 2-micron laser transmitter development at NASA Langley Research Center for coherent-detection lidar profiling of winds. The novel high-energy, 2-micron, Ho:Tm:LuLiF laser technology developed at NASA Langley was employed to study laser technology currently envisioned by NASA for future global coherent Doppler lidar winds measurement. The 250 mJ, 10 Hz laser was designed as an integral part of a compact lidar transceiver developed for future aircraft flight. Ground-based wind profiles made with this transceiver will be presented. NASA Langley is currently funded to build complete Doppler lidar systems using this transceiver for the DC-8 aircraft in autonomous operation. Recently, LaRC 2-micron coherent Doppler wind lidar system was selected to contribute to the NASA Science Mission Directorate (SMD) Earth Science Division (ESD) hurricane field experiment in 2010 titled Genesis and Rapid Intensification Processes (GRIP). The Doppler lidar system will measure vertical profiles of horizontal vector winds from the DC-8 aircraft using NASA Langley s existing 2-micron, pulsed, coherent detection, Doppler wind lidar system that is ready for DC-8 integration. The measurements will typically extend from the DC-8 to the earth s surface. They will be highly accurate in both wind magnitude and direction. Displays of the data will be provided in real time on the DC-8. The pulsed Doppler wind lidar of NASA Langley Research Center is much more powerful than past Doppler lidars. The operating range, accuracy, range resolution, and time resolution will be unprecedented. We expect the data to play a key role, combined with the other sensors, in improving understanding and predictive algorithms for hurricane strength and track.

Knowledge-based machine vision systems for space station automation

Computer vision techniques which have the potential for use on the space station and related applications are assessed. A knowledge-based vision system (expert vision system) and the development of a demonstration system for it are described. This system implements some of the capabilities that would be necessary in a machine vision system for the robot arm of the laboratory module in the space station. A Perceptics 9200e image processor, on a host VAXstation, was used to develop the demonstration system. In order to use realistic test images, photographs of actual space shuttle simulator panels were used. The system's capabilities of scene identification and scene matching are discussed

Economic Adversity and Entrepreneurship-led Growth - Lessons from the Indian Software Sector

It is commonly believed that the business environment in developing countries does not allow productive technology-based entrepreneurship to flourish. In this paper, we draw on the experience of Indian software firms where entrepreneurial growth has belied these predictions. This paper argues that the business models chosen by Indian firms were those that best aligned the country's abundant labour resources and advantages to global demand. Many potentially higher value added opportunities struggled to attain success, but the qualitative value of experimental failures and the capability gaps they exposed was invaluable for collective managerial learning in the industry. Second, the paper also shows that the presence of growth opportunities and the success of firms stimulated institutional evolution to promote entrepreneurial growth. Last we show that the distinctive aggregate contribution of entrepreneurial firms was that they outperformed business houses and multinational subsidiaries in their more productive use of available capital resources whilst achieving similar levels of growth in output and employment. This paper draws upon an earlier shorter paper co-authored with Mike Hobday and titled 'Overcoming Development Adversity: How Entrepreneurs Led Software Development in India'.technology entrepreneurship, institutions and economic development, Indian software, intellectual property rights