Thesis (Ph.D.)--University of Melbourne, Melbourne School of Land and Environment, 2009. / Typescript. Includes bibliographical references.

Thesis (M.S.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 52-53). Also available on the World Wide Web.

The aim of this work is to increase the applicability of Coherent Anti-Stokes Raman Spectroscopy (CARS) to temperature measurement in practical devices. Particular emphasis is placed on combustion thermometry and high pressure steam systems are also considered. A study is made of the temperature measurement accuracy attainable in the range 290 to 1050 K, using broadband CARS. Accuracies of 1 - 2% are attained, and laser cross coherence effects are found to be important. The determination of temperature probability density functions is of great importance to combustion science. Their measurement using single shot CARS requires the analysis of very large numbers of spectra. A study is made of fast methods of data analysis and the temperature measurement precision attainable using them. A very rapid data analysis method suitable for use in fluctuating temperature, pressure and concentration environments is developed. The temperature precision attainable using CARS is limited by CARS signal noise. For systems with high temperature fluctuations, detector counting statistics are found to make a dominant contribution to this. The spread in measured temperature probability density function width due to signal noise is characterised for the CARS system used, as a function of CARS signal strength for the temperature range 290 to 1050 K. A fast CARS signal analysis method is applied to map temperatures and temperature fluctuations in the flame zone of a turbulent oil spray furnace. The temperature measurements are compared with Discrete Droplet and Continuous Droplet oil spray model predictions (Stopford, 1984) with good agreement, particularly in the former case. In the post flame region, where turbulent fluctuations are less severe, averaged measurements of H[2]O concentrations were made.

Master of Science / Department of Biological & Agricultural Engineering / Ajay Sharda / In recent years, the technology employed on precision row-crop planters has rapidly advanced. These new technologies include automatic downforce control systems and electronic drive singulation seed meters. These new technologies offer producers higher productivity through high speed planting and increased yield potentials through accurate seed spacing and placement. To begin to understand the benefits and performance of these new technologies, research must be conducted that specifically targets these new systems. With this research, producers would be able to better select equipment for their operation and have a deeper understanding of proper system operation and settings. A test stand, of a scissor-lift type design, was developed to evaluate row crop planter automatic downforce systems. Evaluation of a planter’s automatic downforce system is important for understanding the planter’s capability of maintaining target seeding depth throughout varying field conditions. The test stand consists of a horizontal platform that can raise and lower to simulate terrain changes as well as a mechanism to load the planter row unit’s opening discs to simulate varying soil texture. The vertical height of the test stand and the disc load can be varied in real-time based on utilizing real-world scenarios under simulated conditions to evaluate downforce system response. The stand incorporated several sensors to obtain the overall applied downforce, applied disc load, applied gauge wheel load, and hydraulic pressure. The test stand’s capabilities were evaluated and found to be satisfactory for planter downforce system testing. The test stand was then used to evaluate a commercial automatic downforce system when operating under simulated field conditions. Field data was used to create simulations representing soil type changes, planter operating speed changes, and extreme conditions such as a hard, packed clay or rocky soil type. It was found that the evaluated downforce system was able to maintain target gauge wheel load to within ±223 N for at least 94% of the time during all simulations. This would suggest that the planter would be able to maintain target seeding depth for at least 94% of field operations. Another key aspect for precision agricultural planters is to achieve accurate seed spacing at varying speeds. An electronic drive singulation seed metering system was evaluated to gather the meter’s effectiveness for high speed planting during straight and contour farming mode using simulated field conditions. The simulated conditions were used to gather the meter’s response when encountering high planting speeds, accelerations, decelerations, point-rows, and contours. These meters were found to be highly accurate, with less than 1.5% error in target seed meter speed during all simulated conditions. The meters were also found to have a response time that was always 0.34 seconds or less for all simulated conditions.

No description available.

No description available.

Precision farming integrates satellite coordination and information communication technologies into farming practices to deliver self-driving and auto-regulating machinery and equipment to farmers, who can afford to invest, right across the globe. It is often sold on the basis that it can help clean up or ‘ecologically modernise’ conventional, industrial agriculture. It should also increase production rates in industrial agriculture to help to ‘feed the world’ as well as being cost effective in ways that could make farmers more money – miracle-grow formula and win-win technology. There are critical concerns that precision farming facilitates a continuing trend of transnational firms appropriating control over agricultural industries. Many neo-Marxist or neo-Weberian critics contend that any ‘green’ benefits fall secondary to the more dominant social and economic trend of ongoing capital accumulation, increasing rationalisation and industrial progress that has been deemed detrimental to natural environments and human populations. These social and economic pressures are actually the real drivers in change. Rather than greening industrial agriculture, precision farming is another way of masking over and profiting from the risks caused by ongoing capitalist accumulation and industrial agriculture. The other set of concerns are to do with human culture and labour. Farming is the grass roots of modern civilisation and dependent upon human labour, knowledge and cultural methods. With the introduction of data over knowledge, and auto-steering tractors over human labour and skills, what kinds of impacts will this have on farm families, rural cultures within countryside landscapes in Britain or other countries where precision farming is being adopted? As a farmer’s son, I was concerned about the impact the computerisation of agriculture will have on family farms, nature and rural communities. I spent four years interviewing and working with a cooperative group of Duchy of Cornwall farmers in the West Country of England. I wanted to know why they were using these new technologies and the kinds of benefits, impacts or outcomes that they experienced following adoption. The results tend to confirm critics’ concerns, unfortunately. Precision farming has much more to do with the organising of agricultural production. The restructuring of farming by way of precision farming greater empowers transnational agribusinesses and Agri-Food supply chains, rather than protecting the environment, feeding hungry people or making family farming more sustainable. I conclude my research by suggesting that it is not technology, or agricultural technologies such as precision farming that will deliver these end goals in and of them selves. There could be room to improve precision farming systems if they are coupled with well-managed policy designs and agri-environmental schemes.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Forests present spatial-temporal strucutre, and their management can be aided by geostatistics. The present study aimed to use geostatistics in the experimental forest management of Mixed Ombrophylous Forest (MOF), in Rio Grande do Sul, Brazil, with two case studies. The specific objectives were to determine areas of production for a population of Araucaria angustifolia and check the sensitivity of geostatistics to different intensities of management (selective wood harvesting), at different time points, before and after the intervention in the forest. The first study was carried out in an area of 11.35 ha in Tapera, using census data from a population of Araucaria, which was used as a virtual sampling. Punctual ordinary kriging and co-kriging were used to the data of 52 virtual sampling units (30x30m) obtained. Cross semivariograms were adjusted based on the spatial structure of the number of individuals for basal area (G), volume (V), biomass (B) and carbon (C) combined through the use of map algebra to determine the production zones (PZ). The second study was held in Tupi Farm, Nova Prata, using sample units of 0.50 ha, with subunits of 10x10 m, where selective wood harvestings were implemented in 2002, with the removal of 0 (control), 20 (light harvest), 40 (medium harvest) and 60% (heavy harvest) of basal area in all diameter class. Inventories were carried out in 2001 (pre-harvesting), 2006 and 2010 (1st and 2nd monitoring). The available data were basal area and commercial volume, organized by subunits. In the first study, low, medium and high production zones were obtained (55.03, 35.54 and 9.43 % for the area of forest fragment, respectively). We obsereved that the forest was under disturbance and the population had balanced diameter distribution. In the second study, the light harvesting caused the less changes in the spatial structure of the forest, more noticeable in the simulated surface relative to the semivariogram, with the replacement of the wood removed when compared to the others. The control area was not more structured than the light harvesting, besides producing less wood. To the medium harvesting we observed pure nugget effect because it intensified the existing randomness in the sample unit prior to the intervention. However, in the heavy harvesting, there were major changes in the forest structure, where areas of high basal and commercial volume areas have become low value areas due to the mortality of individuals remaining in the former, and to the increase and inflow of trees occurring in the latter. The light selective harvesting was the most suitable, and it was spatially less structured, but more productive when compared to the control. Therefore, geostatistics may be used in forest management since it detects changes in the spatial structure of the forest and describes the behavior of variables. / As florestas possuem estrutra espaço-temporal, e seu manejo pode ser auxiliado pela geoestatística. O presente trabalho teve como objetivo geral utilizar a geoestatística no manejo florestal experimental de Floresta Ombrófila Mista - FOM, no Rio Grande do Sul, tendo dois estudos de caso. Os objetivos específicos foram determinar zonas de produção para uma população de Araucaria angustifolia, e verificar a sensibilidade da geoestatística à diferentes intensidades de manejo (cortes seletivos), em distintas épocas, antes e após, a intervensão na floresta. O primeiro estudo foi realizado numa área de 11,35 ha, em Tapera, com uso de dados censitários de uma população de araucária, onde fez-se uma amostragem virtual. Foram utilizadas krigagem ordinária pontual e co-krigagem, aos dados de 52 unidades amostrais virtuais (30x30 m) obtidas. Foram ajustados semivariogramas cruzados, a partir da estrutura espacial do número de indivíduos, para área basal (G), volume (V), biomassa (B) e carbono (C), combinados por meio de álgebra de mapas para determinar as zonas de produção (ZP). O segundo foi realizado na Fazenda Tupi, em Nova Prata, com uso de parcelas de 0,50 ha, divididas em subunidades de 10x10 m, onde foram realizados cortes seletivos em 2002, com retirada de 0% (testemunha), 20% (corte leve), 40% (corte médio) e 60% (corte pesado) de área basal em todas as classes de diâmetro. Os inventários foram realizados em 2001 (pré-exploratório), 2006 e 2010 (1º e 2º monitoramentos). Os dados disponíveis dos mesmos foram G e volume comercial, organizados por subunidades. No primeiro trabalho foram obtidas zonas de baixa, média e alta produção (55,03; 35,54 e 9,43% da área do fragmento florestal, respectivamente). A floresta encontra-se sob distúrbio e a população apresentou distribuição diamétrica balanceada. No segundo estudo, o corte leve foi o que causou menores alterações na estrutura espacial da floresta, mais perceptível na superfície simulada em relação ao semivariograma, havendo a reposição da madeira retirada. A testemunha não mostrou-se mais estruturada que o mesmo, além de ter produzido menos madeira. Para o corte médio observou-se efeito pepita puro, pois este intensificou a aleatoriedade existente na parcela anteriormente à intervenção. Já no corte pesado, houve grandes mudanças na estrutura da floresta, onde zonas de altos valores de G e volume comercial passaram a ser zonas de baixos valores, devido a mortalidade de indivíduos remanescentes na primeira, e aos incremento e ingressos ocorridos na segunda. O corte seletivo leve foi o mais indicado, e em relação a testemunha, apresentou-se menos estruturado espacialmente, porém mais produtivo. Conclui-se que a geoestatística pode ser utilizada no manejo florestal, pois detecta as mudanças na estrutura espacial da floresta e descreve o comportamento de variáveis.

The impact of Automatic Section Control (ASC) as a tool of Precision Agricultural Technology as considered in the more efficient application of inputs to produce the four major crops, corn, soybean, HRSW, and canola in the North Dakota Prairie Pothole Region. Reduction in machinery overlap in the sample 105 fields was calculated by simulating the routing paths of a 60-feet wide planter with 24 sections controlled and a 120-feet wide boom sprayer with individual nozzle control. The dollar and percentage seed and chemical costs that a farm can save by reducing overlapping area were calculated. Impact of field parameters on net savings were estimated by developing and estimating an econometric model. Results show that ASC can save substantial cost in the sample fields while field shape had the highest significant impact on net cost savings. / North Dakota State University. Department of Agribusiness and Applied Economics

International Telemetering Conference Proceedings / October 18-21, 2004 / Town & Country Resort, San Diego, California / In this paper, we develop a method for achieving high precision of time and frequency synchronization among multiple base stations in GPS system. We first describe the basic theory of timing and frequency checking, and then analyze several error sources which influence the precision of time and frequency synchronization. Furthermore, we derive explicit formula for calculating the precision of time and frequency. Tested results have indicated that our method can indeed achieve very high time and frequency precision.