Thesis (M.S.)--Ohio University, August, 2004. / Title from PDF t.p. Includes bibliographical references (leaves 81-82).

Thesis (M.S.)--Ohio University, August, 2004. / Title from PDF t.p. Includes bibliographical references (leaves 62-63).

Coal powered power plants account for more than 40 percent of the electricity production of the United States. The combustion of coal results in a large number of solid waste materials, or coal combustion byproducts (CCBs). These waste materials are stored in landfill or ponds. The construction industry is heavily reliant on concrete which is used to make the building blocks for any type of structures, bricks. Concrete is a composite material made of a binder and coarse and fine aggregate. The most widely used binder in concrete production is Ordinary Portland Cement (OPC). Since cement manufacture is costly and environmentally damaging, research has increased in recent years to find a more readily available binder. This study aims at investigating the properties of Illinois fly ash as a binder in the production of geopolymer concrete. Geopolymer concrete is an innovative material made by using Alumina and Silica rich materials of geological origins as a binder as well as an alkali activated solution. Sodium Silicate and Sodium Hydroxide were used to make the activator solution of two different ratios. Geopolymer Concrete with a ratio of 1:1 of Sodium Silicate to Sodium Hydroxide reached a compressive strength above 6000 psi while samples made with a ratio of 1:2 reached a compressive strength above 4000 psi. This environmentally-friendly, green concrete was also found to have a cost comparable to conventional concrete.

Since a substantial amount of coal combustion byproducts (CCB) are produced each year, generating value-added product from fly ash, which is a major constituent of these CCBs, has been an important area of research for several decades. Natural magnetite (NM), which is used to maintain dense medium slurry pulp density in coal preparation plants, has a current market value of more than $200 per ton. The use of fly ash derived magnetite (FAM) as an alternative to natural magnetite has potential benefits for dense medium processes, such as lower cost, greater stability at low medium density, more efficient delivery systems. This study developed a suitable processing scheme to extract high-grade (> 96%) magnetite from fly ash generated from burning high sulfur coal, and investigated the suitability of the FAM product for dense medium application in coal preparation plants. A classifying cyclone was utilized in the process flow sheet for the pre-concentration of FAM in its underflow stream, which was enriched to high grade FAM by a single stage wet magnetic separator of low intensity (~1000 gauss). A statistically designed experimental program was utilized to maximize the magnetite grade and recovery achieved from the above mentioned flow sheet. The FAM product particles had a slightly coarser particle size distribution than the NM particles. In addition, the FAM particles were found to have a spherical shape; but about one unit lower specific gravity in comparison to the NM particles. However, the F5 Stability Index of the resulting FAM product was found to be in the desired range of 30 to 40 for its suitable application as a dense medium. The coal cleaning performance obtained from a 0.15 m diameter dense medium cyclone using dense medium prepared from both of FAM and NM, were quite similar. However, the effective separation density (SG50) obtained from the FAM-based dense medium was significantly different from the medium density; this may need further investigation in future. A preliminary economic analysis, conducted for a hypothetical mini-plant having a fly ash handling capacity of 100 ton/hour, indicated the cost of FAM extraction to be nearly $5/ton. The cost assumes that the FAM extraction plant is located at the fly ash producing utility site and does not include the cost of thermal drying that may be required to reduce the moisture content of the FAM filter cake produced at the FAM plant. A preliminary civil engineering study conducted to investigate the effect of FAM extraction on the compressive strength property of the non-magnetic flyash (left behind after FAM extraction) failed to produce a conclusive finding. The specimens prepared using 10% and 30% fly ash replacements indicated that the compressive strength does not change due to FAM extraction. However, the specimens using 20% fly ash replacement indicated that compressive strength does change due to FAM extraction. Hence, a more detailed study is recommended to investigate this discrepancy.

No description available.

Thermal power station in most countries is saddled with the problem of fly ash disposal and unless suitable avenues are found for its proper use, this would pose a gigantic problem to the power sector. Disposal of huge quantities of fly ashes without proper care causes considerable impact on the environment particularly the one leading to soil and groundwater contamination. On the other hand, fly ashes have many desirable properties which can find applications in civil engineering, especially in geotechnical engineering. The pozzolanic reactivity is one of the important properties of fly ashes that enhance its application. Thought the fly ashes with self – pozzolanic property are well utilized, fly ashes with insufficient free lime, such as class F fly ashes are being grossly underutilized and they form a considerable portion of fly ashes that are disposed. Yet another factor restricting the use of fly ash is the concern about the leachability of lime under field conditions particularly under saturated or partially saturated conditions. Hence an attempt is made in this thesis, to reduce the lime leachability of class F fly ashes with different additives. Thus, selection of right amounts of additives to reduce the lime leacability is an important aspect studied in this thesis. Effect of such as strength, compressibility, and CBR value is also investigated. Another simple way to reduce the problem of disposal of fly ash is to utilize it for the construction of waste disposal sites particularly for lining solid waste disposal facilities in place of the natural clay materials which are very often procured by excavating and transporting from far off places. Also, the capacities of fly ashes to sorb heavy metal that are likely to be present in the leachates generated from the industrial wastes have been studied. Of the other factors limiting the generous use of fly ashes is the leachability of several trace elements present in them. Hence the leachability of trace metals from fly ashes under different practical situations, before and after incorporating the selected additives for improving the engineering properties of fly ashes, has been studied. The thesis is presented in 10 chapters. The relevant background for the studies and scope of the work is given Chapter 1. Sources of the fly ashes collected for the investigating along with their physical and chemical properties are presented in chapter 2. Two low line fly ashes are collected directly from the electronic precipitators of the thermal power plants located at Neyvelli town of the Tamil nadu and Maddanur town of Andhra Pradesh, India, named NFA and MFA respectively. MFA has greater finer particle content than NFA. The particles of MFA Have rougher surface compared to those of NFA. Both of fly ashes have predominantly quartz and mullite phase in them. The silica, total lime and carbon contents which have major influence on the pozzolanic reactivity of fly ashes vary considerably in the both the fly ashes. Lime leachability is taken as the amount of lime that is converted into soluble form (by dissociation into calcium and hydroxyl ions) under a standardized condition. It can be used to asses the long term sustainability of the strength achieved in fly ashes with lime. Lime leachability studies have been conducted on the fly ashes stabilized with different additives in specially designed moulds. Results presented in Chapter 3 showed that leachability of lime in fly ashes increases with the increase in lime content though it is not in proportion to the increase in lime content. This is because the solubility of lime is less and is independent of the total lime present. The marginal reduction in leachability is mainly due to cemented matrix of fly ash inhibiting the leaching of time. The higher the strength of the matrix the lower is the leachability. Further it is made clear that at any lime content presence of gypsum reduces the time leachability which has been attributed to the transformation of pozzolanic compounds into less soluble form than the compounds formed with lime alone. With the increase in curing period, the amount of lime that leaches from the lime-stabilized fly ashes as well as those treated with gypsum to a considerable extent. The nature of alteration does not seem to change with time as revealed by a good correlation between lime leachability ratios obtained after 7 days and 14 days of curing periods. Chapter 4 presents the results of unconfined compressive strength tests carried out on fly ashes with varying lime and gypsum contents, before soaking and also soaking in several heavy metal solutions, along with the durability to the cycle of wetting and drying. The results revealed that the strength of low lime fly ashes increases with lime content significantly up to the optimum lime content of about 2.5 – 5% and gradually thereafter. Addition of gypsum of 1 – 2.5% increases the strength of fly ashes further at any lime content. Increase in strength with gypsum, which is quite significant at lower lime contents initially, is observed for a considerable period (up to 180 days) at higher lime contents. The increase in strength is as high as 40-fold in some instances. This increase in strength which is also more durable has been attributed to the formation of calcium – sodium – aluminium - silicate hydrate along with calcium silicate hydrate. Further, it is observed that fly ash which responds better to lime stabilization shows accelerated gain in strength due to the addition of gypsum at early curing periods than the fly ash that responds solely to lime. Decrease in lime leachability ratio is a good indication of the increased strength along with the increased durability. California Bearing Radio (CBR) values are of great significance in the utilization of fly ashes in bulk quantities for the construction of road and railway embankments and pavements. Studies conducted to determine the CBR values of fly ashes with different lime and gypsum contents after curing for different time periods are described in chapter 5. The CBR values are observed to increase with lime alone significantly up to 2.5% and only marginally beyond. But the increase in CRB values is considerable with gypsum at any lime content. The increase in CBR value is particularly more with 2.5% gypsum for fly ashes with 2.5% lime. The CBR values of stabilized fly ashes are generally higher for 5 mm depth of penetration than those for 2.5 mm one due to the high stiffness of the matrix formed even at low strain levels. The loss in CBR values with soaking is relatively more at lower curing the periods due to the improper cementation of particles. Even after this significant loss in CBR values, fly ashes with 2.5% lime and 2.5% gypsum register the maximum values after curing under soaked condition. Unlike in the case of unconfined compressive strength, lime leachability values could not be well correlated with the CBR values of fly ashes with different lime and gypsum contents since many more factors influence the CBR values than those of unconfined compressive strength alone. Chapter 6.brings out the effects of addition of lime alone and lime along with gypsum on the compressibility behaviour of the fly ashes. Since the fly ashes when treated with additives develop strength and exhibit lower compression with the passage of time, consolidation testing with conventional duration of load increment may not be appropriate. Hence an attempt has been made to assess the minimum duration of load increment necessary to study the compressibility characteristics of such materials. Thus the compressibility behaviour of fly ashes with additives has been studied using conventional consolidation test with different durations of load increments varying from 30 minutes to 48 hours. The results indicated that 30 minutes of duration of load increment can be used to assess the compressibility behaviour of such materials. The effect of lime which reduces the compression is seen to be maximum from the results obtained with the load duration increment of 30 minutes but gradually reduce with higher duration of load increment. It has also been observed that the rate of decrease in the compressibility is maximum up to 2.5% lime and thereafter gradual. The compressibility of lime –treated fly ashes further reduces when gypsum is incorporated, the optimum gypsum percentage being 2.5. This reduction in the compressibility of fly ashes enhanced by incorporating lime and gypsum makes them versatile in the construction of embankments and for structural fills, particularly reducing the time required in between laying of each lift. It has been brought out that decrease in the lime leachability decreases the compressibility of fly ashes. Fly ash has potential application in the construction of base liners of waste containment facilities. While most of the fly ashes improve in the strength with curing, the ranges of hydraulic conductivities they attain may often not meet the basic requirement of a liner material. Attempts to reduce the hydraulic conductivity by adding lime as gypsum along with lime to both the fly ashes are presented in chapter 7. Hydraulic conductivities of the compacted specimens have been determined in the laboratory using the falling head methods. It has been observed that the addition of gypsum reduces the hydraulic conductivity of the lime treated fly ashes. The reduction in the hydraulic conductivity of the fly ashes containing gypsum is significantly more of sample with high amounts of lime contents (as high as 1000 times) than those with lower amounts of lime. However, there is relatively more increases in the strengths of the samples with the inclusion of gypsum to the fly ashes even at lower lime contents. This is due to the fact that excess lime added to fly ash is not effectively converted in to pozzolanic compounds. Even the presence of gypsum is observed not to activate these reactions with excess lime. On the other hand the higher amount of lime in the presence of gypsum is observed to produce more cementitious compounds which block the pores in the fly ash. Amount of lime leached in the found to be directly related to the hydraulic conductivity inspite of many –fold variations in the hydraulic conductivity achieved by curing fly ash with lime and gypsum. The consequent reduction on the hydraulic conductivity of fly ash would be beneficial in reducing the leachability of trace elements in the fly ash when used as base liner. Fly ash contains trace metals and other substances in the sufficient quantities which may leach out over a period of time. The study has been extended to examine the leachability of a few selected trace metals viz., Cd, Cu, Cr, Mn, Pb and Zn from fly ash before and after incorporating additives has been reported in chapter 9. The standard laboratory leaching test for the combustion residues developed by Van der Sloot et al. has been employed to study the leachabilities of trace elements as a function of liquid to solid (L/S) ratio and pH. The leachability test were conducted on the powdered fly ash samples obtained from unconfined compressive strength tests, conducted after a curing period of 28 and 180 days. It observed that, there is a marked reduction in the relative leachabilities of trace elements present, at the end of 28 days which reduced only marginally at the end of 180 days. Chapter 9 reports the retention capacities of fly ashes for copper, lead and zinc metals ions. Various parameters like contact time, initial concentration and pH have been varied and their effect on retention mechanism studied. The retention order of metals ions, Cu+ 2 > Pb+2>Zn+2, is observed to be the same for both the fly ashes at all pH values. The dominant mechanisms responsible for the retention are precipitation at higher pH’s as hydroxides and adsorption at lower pH’s Due to presence of silica and alumina oxide surface in fly ash. First order kinetic plots have revealed that the rate constant value increases with increase in initial concentration and pH. Langmuir adsorption isotherms have been plotted to study the maximum adsorption isotherms have been plotted to study the maximum adsorption capacities for metal ions under different conditions. The older indicates that the adsorption is predominantly by silica surface than that by alumina or iron oxide surfaces. This thesis demonstrates that incorporation of gypsum along with lime in the optimal proportions not only reduces the lime leachability but also greatly enhances the strength and CBR values, reduces the compressibility and minimizes the leaching of trace elements present in them enhancing the potential of fly ashes for many applications. Detailed conclusions are presented in chapter 10. The study greatly helps in promoting the use of fly ashes for many geotechnical and geo-environmental applications.

Indiana University-Purdue University Indianapolis (IUPUI) / Population genetic structure is difficult to assess in blow flies (Diptera: Calliphoridae) due to high connectivity and genetic diversity of subpopulations. Previous studies revealed high relatedness among individuals within wild samples of blow fly populations, however broad geographic structure was absent. The aim of this research was to determine if blow fly genetic structure exists at a fine spatiotemporal resolution and, if so, to elucidate the influence of environmental factors and resource availability on fly genetics. Specifically, blow fly population genetic patterns were tested against a null hypothesis that flies adhere to a patchy population model with high genetic diversity (i.e. no structure) and high resource availability. Samples of the black blow fly, Phormia regina Meigen (Diptera: Calliphoridae), were collected at six urban parks in Indiana, USA (=urban) in 2016 and 2017 (N = 14 and 16 timepoints, respectively). Additional sampling in different ecoregions was performed to determine if trends observed at a high-resolution scale were also present at a broad geographic scale. Therefore, P. regina were also collected at four sites within two national parks (the Great Smoky Mountains and Yellowstone National Parks) over a three-day period. Randomly selected females (N = 10) from each sample underwent the following analyses: 1) gut DNA extraction, 2) molecular analysis at 6 microsatellite loci, 3) vertebrate-specific 12S and 16S rRNA sequencing, and, 4) vertebrate fecal metabolite screening. Flies from the national parks and a comparable subset of urban data also underwent stable isotope analysis (SIA) to determine larval food source. Overall, strong seasonal population genetic structure was observed over both years in the urban environment (2016 F’ST = 0.47, 2017 F’ST 0.34), however spatial structure was lacking, as seen in previous studies (2016 F’ST = 0.04, 2017 F’ST 0.03). Weather conditions prior to and on the day of blow fly collections, interspecific competition, and resource availability greatly impacted the genetic diversity and kinship of P. regina. A total of 17 and 19 vertebrate species were detected by flies in 2016 and 2017, respectively, and many flies tested positive for vertebrate feces, suggesting that many varied resources are important for maintaining high gene flow among geographic locations. Genetic diversity was non-existent in flies collected from the Smokies (F’ST = 0.00), while very slight spatial structure existed in the Yellowstone populations (F’ST = 0.07). Environmental factors such as temperature, humidity, and wind speed were all statistically relevant in maximizing fly collections with vertebrate resources. In 720 min of total sampling time in the national parks and a subset of urban data, 28 vertebrate species were identified, and fecal resources appeared to be the most abundant in Yellowstone. Stable isotope analysis revealed a majority of larval resources in the national parks were herbivores, with a more even distribution of carnivore and herbivore carcasses present in the urban environment, which likely explains the high genetic diversity of adult flies in these regions. Overall, the null hypothesis that P. regina adheres to a patchy population model could not be rejected for the Smokies populations. However, the urban and Yellowstone populations appear to adhere to a Levins metapopulation model in which variable availability in resources leads to random bottleneck events in the local populations. Overall, environmental conditions, competition, and resource availability are all important factors influencing P. regina population genetic structure in different environments.

No description available.

While enjoying a passion for outdoor related sports, I had taken an interest in the equipment I used while hunting and fishing. I was fascinated by the precision of the instruments I used to optimize my time spent in the field. This curiosity led to some preliminary designs to further enhance my outings. The joy I received from these projects led me to pursue industrial design as a profession. As a student, I chose to design a product that related to the fishing industry. I selected to design a fly reel for its links to other fishing reels and man's interaction with water. This required a critical analysis of current fly reels and how to enhance its current design. To accomplish this I modified select mechanical elements of the reel. This involved, in some instances, new materials and incorporating different processes to achieve my goal. The innovations I incorporated allowed the reel to be used while fishing for a wider spectrum of fish than the typical fly reel. This flexibility reduces the need to purchase additional reels to pursue different size fish. This has the potential to provide a savings to the consumer and encourage them to fish for a species of fish they would otherwise neglect. In addition to my primary objective, I want to contribute a product that will be an asset to the fishing industry with attention to aesthetics, affordability and ease of use. / Master of Science

Thesis (MSc)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: Experiments using the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), were conducted to determine the mortality of males and females and the ovipositing ability of females fed on two diets. The sugar diet consisted of 5: 1 sugar:protein and the protein diet consisted of 5:1 protein: sugar. Dilutions of 80%, 60%, 40%, 20% and 10% with water of both diets were also provided to the flies. Female longevity was shorter than male longevity. There was no difference in female longevity between fruit flies fed on the two diets. However, males fed on the sugar diet lived longer than those fed on the protein diet. More eggs per female per day were laid by those fed the sugar diet than by those fed the protein diet. There were no differences m oviposition between flies fed on the different concentrations of the two diets. / AFRIKAANSE OPSOMMING: Proewe met die Mediterreense vrugtevlieg, Ceratitis capitata (Wiedemann), is uitgevoer om die mortaliteit van die mannetjies en wyfies, asook eierlegging van wyfies wat met twee verskillende diëte voorsien is, te bepaal. Die onderskeie diëte het uit 'n mengsel van proteïen en suiker (5 dele suiker en 1 deel proteïen) en (5 dele proteïen en 1 deel suiker) bestaan. Verdunnings van 80%, 60%, 40%, 20% en 10% is van die onderskeie diëte gemaak en aan die vlieë voorsien. Daar was geen verskil in die lewensduur van wyfies wat op die twee diëte gevoed is nie. Mannetjies wat op die oorwegende suiker dieët gevoed is, het langer as dié wat op die proteïen dieët gevoed is, geleef. Vlieë wat op die suiker dieët gevoed het, het regdeur 'n hoër gemiddelde daaglikse eierlegging per wyfie as dié wat op die proteïen dieët gevoed het, getoon. Geen noemenswaardige verskil in eierlegging vir vlieë wat op verskillende konsentrasies van die twee diëte gevoed het, is gevind nie.