Thesis--Lund University, 1992. / Added t.p. with thesis statval Includes bibliographical references.

Thesis--Lund University, 1992. / Added t.p. with thesis statval. Includes bibliographical references.

Thesis (MEng)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Studying wild animals in nature is a complex and tedious task for biologists and ecologists. The rugged terrain in which the animals live and hide makes it for researchers difficult to follow and observe the animals. Technology is used to facilitate studies on animals, usually in the form of radio tracking devices. This thesis discusses the problems and shortfalls surrounding the current technology and looks at various ways of improving it. Expanding tracking collars to capture the needed data, as well as improving the radio links to continuously provide data, are seen as the most important improvements. The proposed solution makes use of a wireless network, through which a tracking collar can have an unbroken connection with the outside world. The study focuses on the radio links themselves and topics including antennas, radio frequency bands and propagation effects of the surroundings. An existing routing protocol to use on top of the physical radio links is discussed. Hardware for all parts of the network is designed, built and tested. Proper ways of capturing data in a power efficient way are stated and recommended. Measurements were taken with the hardware prototypes in a location comparable to where the system will ultimately be used. The results obtained proved the feasibility of such a radio network. Radio coverage simulations were set up to predict the coverage that is to be expected by the chosen radios in the location where the tests were done. The simulation parameters were changed until the simulated results most closely matched the real life measurements. Vegetation caused an extra attenuation of around 20dB in the radio signal. Using the tuned parameters for the simulation a network can be designed and costs calculated before huge investments are made. / AFRIKAANSE OPSOMMING: Om wilde diere in die natuur te bestudeer is vir wetenskaplikes ’n uitdagende onderneming. Die ongerepte natuur waarin die diere bly, maak dit vir die dierkundiges moeilik om die diere op te spoor en te agtervolg. Tegnologie word gewoonlik ingespan in hierdie studies en meestal word radiosporingstoestelle gebruik. Hierdie tesis bespreek die probleme en tekortkominge in die bestaande tegnologie. Verskeie moontlike verbeteringe word bekyk. Radiosporingshalsbande wat uitgebrei word om metings te neem, en verbetering van die radioverbindings met die halsbande is twee van die belangrikste punte waarop verbeter kan word. In die voorgestelde verbeterings word ’n radionetwerk gebruik om op ’n deurlopende basis kontak tussen die halsbande en die buitewêreld te verseker. Die studies lê klem op die radioverbindings en onderwerpe soos antennas en radiofrekwensiebande. Radioseine se voortplantingskenmerke in die betrokke omgewing word bespreek. ’n Bestaande netwerkprotokol om op die radioverbindings te implementeer word ook bepsreek. Apparatuur vir alle dele van die netwerk is ontwerp, gebou en getoets. Metodes van datavaslegging op ’n energiedoeltreffende wyse word beskryf en aanbevelings daarvoor gemaak. Metings is geneem met die prototipe van die apparate in ’n plek wat vergelykbaar is met waar die uiteindelike stelsel gebruik behoort te word. Die resulte wat verkry is, het die nut van die radionetwerk bewys. Simulasies van die radiodekking is opgestel om die verwagte dekkings van die betrokke radios in die veld te bepaal. Die simulasieparameters is geleidelik verander totdat die simulasieresultate met die werklike metings ooreenstem. Plantegroei het ’n ekstra verswakking van ongeveer 20dB in die radiosein veroorsaak. Die vasgestelde parameters kan gebruik word in ’n simulasie vir die ontwerp van ’n grootskaalse netwerk. Resultate verkry vanuit die simulasie kan gebruik word vir kosteberekings voordat grootskaalse beleggings gemaak word.

Durante muito tempo as estruturas de concreto foram consideradas livres de manutenção, ou seja, estruturas quase eternas a menos que fossem sobrecarregadas ou destruídas intencionalmente ou por acidente. Esse pensamento caiu por terra nas últimas décadas quando várias estruturas de concreto começaram a apresentar problemas degradando-se bem mais rápido que o esperado. O monitoramento estrutural nasceu da necessidade de acessar a condição de segurança de uma estrutura de forma mais rápida, precisa e com o benefício de criar uma base de dados sobre a estrutura monitorada. O monitoramento de edifícios ainda é um assunto pouco abordado nas pesquisas e publicações. O alto custo agregado às pontes, viadutos e outras grandes estruturas atraem o interesse de pesquisadores e fabricantes de equipamentos. O problema escolhido como alvo no monitoramento a ser desenvolvido foi a degradação de blocos de fundações em concreto armado com reação álcali-agregado (RAA) pela dificuldade de acesso em inspeções. Uma simulação da expansão causado por RAA em concreto foi desenvolvida para experimentos com sensores e técnicas de monitoramento de fundações. No experimento foram testadas aplicações de strain gauges na armadura, na superfície através de um long gauge adaptado e LVDTs (linear variable differential transformer) aplicados na superfície. A ancoragem dos long gauges não suportou o esforço, impedindo a correta avaliação do sensor. Os LVDTs têm grande potencial para acompanhar o desenvolvimento de fissuras, mas sofrem depois de alguma expansão, pois se desalinham com a superfície do concreto. Os strain gauges aplicados na armadura mostraram boa relação com a expansão medida e têm grande potencial no monitoramento. O processo de decisão e projeto do monitoramento para os blocos é explicado e definido. Uma proposta de aplicação do conceito de estrutura tolerante a dano aos blocos de fundação com RAA é dada para otimização de planos de manutenção e intervenções. / For a long time, concrete structures were considered \"maintenance-free\", i.e. quasi eternal, unless they were overloaded or destroyed intentionally or by accident. This thought has been reconsidered in recent decades when several concrete structures began to present problems and degraded much faster than expected. Structural monitoring has been originated from the need to access the safety condition of a structure more quickly, accurately and with the benefit of creating a database of the structure monitored. The high cost related to bridges, overpasses and other large structures still attracts the interest of researchers and equipment manufacturers. However, the monitoring of buildings is still a subject rarely addressed in research and publications. The problem chosen to be addressed in this research is the degradation of reinforced concrete foundation blocks by alkali-aggregate reaction (AAR) due to difficult access during inspections and unpredictable development of the problem. A review on the sensors available on the market and on monitoring techniques used in other structures with the problem was undertaken. A simulation of the AAR`s expansion in concrete has been developed for an experiment with sensors and monitoring techniques of foundations. In this experiment, strain gauges were applied on the reinforcing bars and adapted on a long gauge on the surface. LVDTs (linear variable differential transformer) were also applied on the surface. The anchoring of the long gauges did not support the applied tension, preventing a correct evaluation of the sensor. LVDTs have great potential to monitor the development of cracks, but after the concrete suffering some expansion, they get misaligned with the surface. The strain gauges used in the armor showed a good relation with the expansion and have great potential in monitoring. The whole decision and design process for the structural health monitoring (SHM) for AAR attacked foundation blocks is explained and the project is defined. A proposal of a damage-tolerant approach for the block is given for optimization of maintenance and interventions.

Der verantwortungsbewusste Umgang mit alt- und nachbergbaulichen Strukturen umfasst den Aufbau und die Entwicklung eines Risikomanagementsystems. Aktuelle Informationen über die Stabilität der bergbaulichen Objekte, ihren Zustand und mögliche Auswirkungen auf die Tagesoberfläche werden durch ein Monitoringprogramm bereitgestellt. Der Beitrag behandelt die Zusammenhänge zwischen den bergbaulichen Elementen/ Objekten, den Ereignissen an der Tagesoberfläche, den zu messenden Parametern und den heute zur Verfügung stehenden Monitoringverfahren. In einem besonderen Fokus stehen alle Verfahren, deren Potentiale als besonders untersuchungswürdig eingestuft werden. Dazu zählen insbesondere die Daten des europäischen Erdbeobachtungsprogramms Copernicus. Die bisher gewonnenen Erfahrungen bei der Verschneidung der radarinterferometrischen, multi- und hyperspektralen Daten u.a. der Sentinel-Satelliten, mit den Ereignissen an altund nachbergbaulichen Elementen werden beschrieben. Neben der Analyse von Bodenbewegungsprozessen kommt den Veränderungen des Bodenwassergehaltes, der Vitalität der Vegetation und der Landnutzung eine besondere Bedeutung zu. / The responsible handling of old- and post-mining structures encompasses the installation and the development of a risk management system. Up-to-date information about the mining objects` stability, their condition and possible effects to the ground surface are provided by a monitoring program. This contribution deals with the contexts between the mining objects, the effects to the ground surface, the parameters to be measured and the currently available monitoring methods. The methods which are recognized as extraordinary useful, shall be emphasized within this paper. Among these, the data of the European Earth observation program Copernicus are of a special interest. The to date gained experiences by merging of radar interferometrical, multi- and hyperspectral data with the old- and post-mining elements are being described. Besides the analysis of ground movement processes the variations of soil water, the vegetation’s vitality and the land use are focussed.

The purpose of this dissertation is to demonstrate the ability to design health monitoring systems from a systematic perspective and how, with proper sensor and actuator placement, damage occurring in a structure can be detected and tracked. To this end, a design optimization was performed to determine the best locations to excite the structure and to collect data while using the minimum number of sensors. The type of sensors used in this design optimization was uni-axis accelerometers. It should be noted that the design techniques presented here are not limited to accelerometers. Instead, they allow for any type of sensor (thermal, strain, electromagnetic, etc.) and will find the optimal locations with respect to defined objective functions (sensitivity, cost, etc.). The use of model-based optimization techniques for the design of the monitoring system is driven by the desire to obtain the best performance possible from the system given what is known about the system prior to implementation. The use of a model is more systematic than human judgment and is able to take far more into account by using information about the dynamical response of a system than even an experienced structural engineer. It is understood in the context of structural modeling that no model is 100\% accurate and that any designs produced using model-based techniques should be tolerant to modeling errors. Demonstrations performed in the past have shown that poorly placed sensors can be very insensitive to damage development. To perform the optimization, a multi-objective genetic algorithm (GA) was employed. The objectives of the optimization were to be highly sensitive to damage occurring in potential “hot spots” while also maintaining the ability to detect damage occurring elsewhere in the structure and maintaining robustness to modeling errors. Two other objectives were to minimize the number of sensors and actuators used. The optimization only considered placing accelerometers, but it could have considered different type of sensors (i.e. strain, magneto-restrictive) or any combination thereof.

No description available.

No description available.

Explosions of gas and dust continue to be recognized as an extreme danger in underground coal mines and still occur despite significant technological advances. Mining researchers have been attempting to accurately measure and quantify ventilation and gas properties since early mining; however basic monitoring attempts were limited by the available technologies. Recent advancements in monitoring and communication technologies enable comprehensive atmospheric monitoring to become feasible on a mine-wide scale. Atmospheric monitoring systems (AMS) allow operators to monitor conditions underground in real-time. Real-time monitoring enables operators to detect and identify developing high risk areas of the mine, as well as quickly alert mining personnel underground. Real-time monitoring also can determine whether conditions are safe for mining, to operate ventilation systems more efficiently, and to provide an additional layer of monitoring atmospheric conditions underground. AMS utilizes numerous monitoring technologies that will allow underground coal mines to comprehensively monitor gas and ventilation parameters. AMS are utilized worldwide as well as in the United States, and can be modified to cater to specific hazards at different mines. In the United States, AMS are primarily used to monitor belt lines and electrical installations for smoke, CO, and CH₄, and to automatically alarm at set thresholds. The research in this study investigates and analyzed AMS across the world (specifically Australia, Canada, and United States). Two case studies presented in Chapter 5 focus on the utilization and implementation of AMS in two underground coal mines in the United States. These case studies identify challenges regarding installation, data management, and analysis of real-time atmospheric monitoring data. The second case study provides significant evidence that correlates mine ventilation fan outages and changes in barometric pressure to increases in methane from previous works. This research does not attempt to quantify data, but intends to provide engineers knowledge to utilize, design, and implement an AMS. Several incident scenarios are simulated using ventilation computer software, as well as the benefits of monitoring in past disasters are analyzed. This research does not intend to place blame, but intends to increase the understanding of utilizing and implementing AMS in underground coal mines. / Ph. D.

京都大学 / 新制・課程博士 / 博士(農学) / 甲第24243号 / 農博第2522号 / 新制||農||1094(附属図書館) / 学位論文||R4||N5414(農学部図書室) / 京都大学大学院農学研究科応用生物科学専攻 / (主査)教授 松浦 健二, 教授 大門 高明, 教授 日本 典秀 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM