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Biomass conversion into forms of energy is receiving current attention because of environmental, energy and agricultural concerns. The purpose of this thesis is to analyze the environmental, energy, economic, and technological aspects of using a form of biomass, switchgrass (panicum virgatum), as a partial or complete replacement for coal in power generation and cogeneration systems. To examine the effects of such a substitution, an environmental biocomplexity approach is used, wherein the agricultural, technological, economic, and environmental factors are addressed. In particular, lifecycle analysis (LCA) and a three-dimensional integrated economic, energy and environmental analysis is employed. The effectiveness of alternate technologies for switchgrass preparation, harvest and use in terms of greenhouse gas impact, cost and environmental implications is examined. Also, different scenarios of cofiring and biomass preparation pathways are investigated. Optimization of the total biomass power generation cost with minimum greenhouse gas effect is undertaken using mathematical programming for various alternate competitive biomass processing pathways. As a byproduct of this work a generic tool to optimize the cost and greenhouse gas emissions for allocation of fuel sources to the power generating sinks is developed. Further, this work discusses the sensitivity of the findings to varied cofiring ratios, coal prices, hauling distances, per acre yields, etc. Besides electricity generation in power plants, another viable alternative for reducing greenhouse gases (GHGs) is the utilization of biomass in conjunction with combined heat and power (CHP) in the process industries. This work addresses the utilization of biowaste or biomass source in a processing facility for CHP. A systematic algebraic procedure for targeting cogeneration potential ahead of detailed power generation network design is presented. The approach presented here effectively utilizes the biomass and biowaste sources as external fuel, and matches it with the use and dispatch of fuel sources within the process, heating and non-heating steam demands, and power generation. The concept of extractable energy coupled with flow balance via cascade diagram has been used as a basis to construct this approach. The work also discusses important economic factors and environmental policies required for the cost-effective utilization of biomass for electricity generation and CHP.

An isolated hybrid system comprised of a dispatchable and a non-dispatchable power generation sources, is proposed to supply the load of a remote village in the west region of Haiti. The wind speed data and load data of this remote village are used to study the system. The non-dispatchable generation comes from a nature-dependent wind turbine, and the dispatchable one is a diesel generator. Using MATLAB/Simulink, dynamic simulations are performed to investigate the interaction between these two power sources for the load management, and the voltage and frequency behaviors during wind speed and load variations. Economic analyses of the system are also conducted. The cost of energy (COE), energy payback time (PBT), internal rate of return (IRR) and avoided cost (AC) of CO2¬, NOx and PM (Particles Materials) of the hybrid system are computed, and results are compared with those of the baseline diesel only case. Simulation results show that the wind turbine and the diesel generator can be operated suitably in parallel, and the economic analyses show the positive benefits of wind generation in reducing COE and increasing the avoided cost (AC) of emitted pollutions.

Energy security is probably one of the most challenging issues around the world. Therefore, the focus on methods of decreasing energy consumption and consequently its associated greenhouse gas (GHG) emissions is intensified by policy decision makers. Residential buildings are one of the potential sectors that can reduce its energy consumption in various ways, such as: improving thermal characteristics of the building, using more energy efficient appliances and using renewable energy resources. Among these methods, integration of solar technologies to buildings provides one of the substantial opportunities for reducing energy consumption and the associated GHG emissions in Canada’s residential sector. Therefore, this research work was conducted to assess the impact of solar technologies and solar technology integration strategies on the end-use energy consumption and the associated greenhouse gas (GHG) emissions in Canadian residential sector by using a new state-of-the-art end-use energy and GHG emissions model of the Canadian residential housing stock. The new Canadian residential end-use energy and emissions model that is used in this project incorporates a 17,000 house database developed using the latest data available from the Energuide for Houses database, Statistics Canada housing surveys, and other available housing databases, and utilizes an advanced building energy simulation program as its simulation engine. A new neural network methodology is incorporated into the model to estimate the socio-economic and demographic dependencies of the energy consumption of discretionary end-uses such as appliances, lighting and domestic hot water, while a new approach is used to incorporate occupancy, appliance, lighting and domestic hot water load profiles into the model. A new method is used to calculate the GHG emissions from electricity consumption used in the residential sector based on the actual electrical generation fuel mix and the marginal fuel used in each province as a function of time of the year. Each solar technology is added to the eligible houses to examine the interrelated effects of integrated solar technologies and practices on the housing stock. The objective is to conduct realistic assessments of the cost effectiveness, energy savings and GHG emission reduction benefits of integrated solar technologies for the entire Canadian housing stock (CHS) as well as for different regions, house type, and fuel types. The integrated solar technologies and practices that are assessed include passive solar with added thermal storage and motorized blinds, solar DHW system, and photovoltaic electricity and heat generation systems. This project provides a comprehensive techno-economic and emissions assessment of integrated solar technologies and practices, and will be useful for developing national and regional policies and strategies related with integrating solar energy into the residential sector.

At a time when global environmental change is posing a growing challenge to the world’s economy and creating uncertainties to livelihood of its inhabitants, Coal thermal power plants are under pressure to meet stringent environmental regulations into achieving worldwide set millennial goals for mitigating the effect of emission gases on the atmosphere. Owing to its abundance, it is unlikely to see the use of coal completely missing from the global energy mix within the next hundred years to come. While innovative emission reduction technologies are evolving for the better, trendy technological solutions which require reintegration of these coal plants with alternative greener fuels are growing at the moment. Among these solutions, the following paper investigates possible means for repowering a coal steam power plant with indirect solar heating solutions to boost its annual outputs. Two widely deployable solar thermal technologies, parabolic trough and Central tower receiver systems, are introduced at different locations in the steam plant to heat working fluid thereby enhancing the thermodynamic quality of steam being generated. Potential annual energy output was estimated using commercially available TRNSYS software upon mass and heat balance to every component of solar and steam plant. The annual energy outputs are weighed against their plant erecting and running costs to evaluate the economic vitality of the proposed repowering options. The results show that parabolic trough heating method could serve as the most cost effective method generating electricity at competitive prices than solar only powered SEGS plants. While cost may be acceptable in the unit of energy sense, the scale of implementation has been proven to be technically limited. / Kriel Power Plant

Malnutrition is reported to be common in hospitals (10-60%), residential aged care facilities (up to 50% or more) and in free living individuals with severe or multiple disease (>10%) (Stratton et al., 2003). Published Australian studies indicate similar results (Beck et al., 2001, Ferguson et al., 1997, Lazarus and Hamlyn, 2005, Middleton et al., 2001, Visvanathan et al., 2003), but are generally limited in number, with none conducted across multiple centres or in residential aged care facilities. In Australia, there is a general lack of awareness and recognition of the problem of malnutrition, with currently no policy, standards or guidelines related to the identification, prevention and treatment of malnutrition. Malnutrition has been found to be associated with the development of pressure ulcers, but studies are limited. The consequences of the development of pressure ulcers include pain and discomfort for the patient, and considerable costs associated with treatment and increased length of stay. Pressure ulcers are considered largely preventable, and the demand for the establishment of appropriate policy, standards and guidelines regarding pressure ulcers has recently become important because the incidence and prevalence of pressure ulcers is increasingly being considered a parameter of quality of care. The aims of this study program were to firstly determine the prevalence of malnutrition and its association with pressure ulcers in Queensland Health hospitals and residential aged care facilities; and secondly to estimate the potential economic consequences of malnutrition by determining the costs arising from pressure ulcer attributable to malnutrition; and the economic outcomes of an intervention to address malnutrition in the prevention of pressure ulcers. The study program was conducted in two phases: an epidemiological study phase and an economic modelling study phase. In phase one, a multi centre, cross sectional audit of a convenience sample of subjects was carried out as part of a larger audit of pressure ulcers in Queensland public acute and residential aged care facilities in 2002 and again in 2003. Dietitians in 20 hospitals and six aged care facilities conducted single day nutritional status audits of 2208 acute and 839 aged care subjects using the Subjective Global Assessment, in either or both audits. Subjects excluded were obstetric, same day, paediatric and mental health patients. Weighted average proportions of nutritional status categories for acute and residential aged care facilities across the two audits were determined and compared. The effects of gender, age, facility location and medical specialty on malnutrition were determined via logistic regression. The effect of nutritional status on the presence of pressure ulcer was also determined via logistic regression. Logistic regression analyses were carried out using an analysis of correlated data approach with SUDAAN statistical package (Research Triangle Institute, USA) to account for the potential clustering effect of different facilities in the model. In phase two, an exploratory economic modelling framework was used to estimate the number of cases of pressure ulcer, total bed days lost to pressure ulcer and the economic cost of these lost bed days which could be attributed to malnutrition in Queensland public hospitals in 2002/2003. Data was obtained on the number of relevant separations, the incidence rate of pressure ulcer, the independent effect of pressure ulcers on length of stay, the cost of a bed day, and the attributable fraction of malnutrition in the development of pressure ulcers determined using the prevalence of malnutrition, the incidence rate of developing a pressure ulcer and the odds risk of developing a pressure ulcer when malnourished (as determined previously). A probabilistic sensitivity analysis approach was undertaken whereby probability distributions to the specified ranges for the key input parameters were assigned and 1000 Monte Carlo samples made from the input parameters. In an extension of the above model, an economic modelling framework was also used to predict the number of cases of pressure ulcer avoided, number of bed days not lost to pressure ulcer and economic costs if an intensive nutrition support intervention was provided to all nutritionally at risk patients in Queensland public hospitals in 2002/2003 compared to standard care. In addition to the above input parameters, data was obtained on the change in risk in developing a pressure ulcer associated with an intensive nutrition support intervention compared to standard care. The annual monetary cost of the provision of an intensive nutrition support intervention to at risk patients was modelled at a cost of AU$ 3.8-$5.4 million for additional food and nutritional supplements and staffing resources to assist patients with nutritional intake. A probabilistic sensitivity analysis approach was again taken. A mean of 34.7 + 4.0% and 31.4 + 9.5% of acute subjects and a median of 50.0% and 49.2% of residents of aged care facilities were found to be malnourished in Audits 1 and 2, respectively. Variables found to be significantly associated with an increased odds risk of malnutrition included: older age groups, metropolitan location of facility and medical specialty, in particular oncology and critical care. Malnutrition was found to be significantly associated with an increased odds risk of having a pressure ulcer, with the odds risk increasing with severity of malnutrition. In acute facilities moderate malnutrition had an odds risk of 2.2 (95% CI 1.6-3.0, p<0.001) and severe malnutrition had an odds risk of 4.8 (95% CI 3.2-7.2, p<0.001) of having a pressure ulcer. The overall adjusted odds risk of having a pressure ulcer when malnourished (total malnutrition) in an acute facility was 2.6 (95% CI 1.8-3.5, p<0.001). In residential facilities, where the audit results were presented separately, the same pattern applied with moderate malnutrition having an odds risk of 1.7 (95% CI 1.2-2.2, p<0.001) and 2.0 (95% CI 1.5-2.8, p<0.001); and severe malnutrition having an odds risk of 2.8 (95% CI1.2-6.6, p=0.02) and 2.2 (95% CI 1.5-3.1, p<0.001), for Audits 1 and 2 respectively. There was no statistical difference between these odds risk ratios between the audits. The overall adjusted odds risk of having a pressure ulcer when malnourished (total malnutrition) in a residential aged care facility was 1.9 (95% CI 1.3-2.7, p<0.001) and 2.0 (95% CI 1.5-2.7, p<0.001) for Audits 1 and 2 respectively. Being malnourished was also found to be significantly associated with an increased odds risk of having a higher stage and higher number of pressure ulcers, with the odds risk increasing with severity of malnutrition. The economic model predicted a mean of 3666 (Standard deviation 555) cases of pressure ulcer attributable to malnutrition out of a total mean of 11162 (Standard deviation 1210), or approximately 33%, in Queensland public acute hospitals in 2002/2003. The mean number of bed days lost to pressure ulcer that were attributable to malnutrition was predicted to be 16050, which represents approximately 0.67% of total patient bed days in Queensland public hospitals in 2002/2003. The corresponding mean economic costs of pressure ulcer attributable to malnutrition in Queensland public acute hospitals in 2002/2003 were estimated to be almost AU$13 million, out of a total mean estimated cost of pressure ulcer of AU$ 38 526 601. In the extension of the economic model, the mean economic cost of the implementation of an intensive nutrition support intervention was predicted to be a negative value ( -AU$ 5.4 million) with a standard deviation of $AU3.9 million, and interquartile range of –AU$ 7.7 million to –AU$ 2.5 million. Overall there were 951 of the 1000 re-samples where the economic cost is a negative value. This means there was a 95% chance that implementing an intensive nutrition support intervention was overall cost saving, due to reducing the cases of pressure ulcer and hospital bed days lost to pressure ulcer. This research program has demonstrated an independent association between malnutrition and pressure ulcers, on a background of a high prevalence of malnutrition, providing evidence to justify the elevation of malnutrition to a safety and quality issue for Australian healthcare organisations, similarly to pressure ulcers. In addition this research provides preliminary economic evidence to justify the requirement for consideration of healthcare policy, standards and guidelines regarding systems to identify, prevent and treat malnutrition, at least in the case of pressure ulcers in Australia.

Diss. (sammanfattning). Umeå : Sveriges lantbruksuniv. / Härtill 5 uppsatser.

Licentiatavhandling Uppsala : Sveriges lantbruksuniversitet, 2006. / Härtill 2 uppsatser.

Coal spirals are widely used in coal preparation plants around the world to clean fine coal, typically in the 1 x 0.15 mm size range. Despite their popularity and the trend toward increased automation in modern coal preparation plants, adjustments to the critical process variable for coal spirals, i.e., product splitter position, continue to be done manually. Since spiral feed in a plant tends to fluctuate on a regular basis, timely manual adjustment of splitter position in tens or hundreds of spirals operating in a plant is nearly impossible. As a result, the clean coal yield from a spiral and also the overall plant suffers on a regular basis. The main goal of this study was to develop a suitable sensor and control system to adjust the product splitter position of a full-scale spiral. Some of the basic properties of coal slurry were thoroughly investigated for their on-line measurability and for their correlations with the density of the constituent solid particles. After experimenting with electrical capacitance- and conductivity- (i.e., reciprocal of resistivity) based sensing techniques, a conductivity-based tube sensor was developed for measuring density of solid particles in the spiral trough. Two sensors were used to establish a density gradient in the critical region across the spiral trough at the discharge end. Based on this continuously monitored density gradient, a PIC24 microcontroller was programmed to send a signal to a DC gear motor that would move the splitter arm in the appropriate direction when sufficient variation in conductivity was detected. Currently, a cycle time of 5 minutes is used for the spiral control system; however, in a commercial application, the cycle time could be lengthened to 30 or 60 minutes. The automation system has been validated by examining the performance of a full-scale spiral while deliberately changing factors like feed solid content, feed washability characteristics, and feed slurry ionic concentration. With a full-scale compound spiral programmed to achieve a specific gravity of separation at 1.65 by an automatic adjustment of the splitter position, the actual D50 values achieved for two separate tests were 1.64 and 1.73. The close proximity of target and actual D50 values is indicative of the effectiveness of the developed system. The next step in near-term commercialization of this proprietary spiral control system will be a longer term (several months) in-plant demonstration. The main goal of this study was to develop a suitable sensor and control system to adjust the product splitter position of a full-scale spiral. One of the basic properties of coal slurry was thoroughly investigated for its on-line measurability and for its correlation with the constituent solid density of the slurry. After experimenting with electrical capacitance- and conductivity- (i.e., reciprocal of resistivity) based sensing techniques, a conductive-based tube sensor was selected for measuring solids density of particles in the spiral trough. Two sensors were used to establish a density gradient in the critical region across the spiral trough at the discharge end. Based on this continuously monitored density gradient, a PIC24 microcontroller was programmed to send a signal to a DC gear motor that would move the splitter arm when sufficient variation in conductivity was detected. Currently, a cycle time of 5 minutes is used for the spiral control system; however, in a commercial application, the cycle time could be lengthened to 30 or 60 minutes. The automation system has been validated by examining the performance of a full-scale spiral while deliberately changing factors like feed solid content, feed washability characteristics, and feed slurry ionic concentration. With compound spirals programmed to achieve a specific gravity of separation at 1.65, actual D50 values achieved for two separate tests were 1.64 and 1.73. The close proximity of target and actual D50 values is indicative of the effectiveness of the developed system. The next step in near-term commercialization of this proprietary spiral control system will be a longer term (several months) in-plant demonstration.

Master of Agribusiness / Department of Agricultural Economics / Jason S. Bergtold / Cover crops can be used as forage for cattle and other grazing animals. This research investigated the net returns of using cover crops for forage or grazing under four scenarios. These scenarios were: 1) a mixed crop and livestock producer who owns a herd of cattle and has both dry or pregnant cows and weaned calves available to graze corn stover and cover crops; 2) a crop farmer who purchases stocker cattle for the purpose of grazing the cover crop and corn stover; 3) a crop farmer who leases out a corn stover and cover crop field to a livestock producer (and who provides value-added services to the livestock producer for a fee); and 4) an integrated operation with crops and cattle where cover crops are not grown and hay is fed to cattle during the winter months. Each of these scenarios had different budgets, risks, and profit potentials. The research aimed to address the risks and profit potentials for each scenario. The stocking density was initially set at three cows and 31 steers for a period of 90 days, and alternatively, three cows and 25 steers for a period of 120 days. Two sets of cattle pricing data were used: the average historical prices from 1992 to 2011 and reported prices from a regional stockyard for the period of November 2016 to March 2017. The results showed that the initial stocking densities used for scenarios one and two were too low to provide profitable net returns regardless of pricing data used. Net returns for scenario three were also not profitable based on the services rendered and the management fee charged. Scenario four was profitable on one occasion. November steers with a 500 lb. average starting weight fed hay and concentrate for 120 days resulted in a positive net return of $375. A second analysis was done using stocking rates of 50, 75, or 100 steers to determine if increasing stocking density would result in a positive net return using only the 2016/2017 pricing data and only evaluating net returns on 2.0 and 2.5 lbs. of average daily gain. Positive net returns were achieved at various start weights and average daily gain rates at stocking rates of 75 and 100 animals. No positive net returns were realized at the stocking rate of 50 animals/100 acre field. The management fee charged for providing management services under scenario three was adjusted based on stocking densities to determine if a positive net return could be achieved at the set fee rate of $0.875/head/day. At that rate, no stocking rate resulted in a positive net return. Using the cost data, less the $900 field lease income, a breakeven pricing point for the management fee was determined for each stocking density and grazing duration within the scenario. Management of cost factors to achieve greater chances of profitability and additional research needs are discussed.