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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
661

Black flies (Diptera: Simuliidae) occurring in Mississippi, and their medical, veterinary, and economic impacts

Nations, Tina M 09 August 2019 (has links)
Little is known about black fly pest species in Mississippi, other than research from the 1930s. A better understanding of the pest species that occur in Mississippi is important for human and animal health. My research focused on what species of black flies occur in Mississippi, their seasonality and distribution, and a detailed systematic survey of the primary pest species. Lastly, I attempted to quantify nuisance effects and economic impacts of black flies on people, backyard poultry, and livestock. I examined scientific literature and records of black flies occurring in the southeastern U.S., and particularly Mississippi. This search revealed several unpublished manuscripts by Dr. George H. Bradley on the biology, ecology, and control of black flies in the Mississippi Delta during the 1930s. These publications were curated and made available to the scientific community. I identified and compiled an annotated list of larval, pupal, and adult stages of black flies occurring in Mississippi, derived from specimens housed in the Mississippi State University Entomological Museum (MEM). These specimens had been collected over several decades by a variety of entomologists, students, and the public. In addition, I included data from thousands of black flies collected during this project. To assess seasonality and relative abundance of the primary pest black fly species in Mississippi, I systematically collected adult black fly specimens for two years, documenting species present, seasonality, adult emergence patterns, and associated meteorological conditions. These ten sites were selected based on Dr. George Bradley's extensive work and complaints from local county extension agents, veterinarians, and municipal public works personnel. For economic, human, and animal health impacts of black flies, I employed a four-tiered approach: 1) a survey of lay and medical literature for reports of human health problems from black fly bites, 2) a query of city and county public works personnel concerning black fly nuisance effects, 3) an analysis of statewide hospital outpatient International Classification of Diseases-9 (ICD-9) discharge data and lastly, 4) a statewide survey of backyard poultry owners to ascertain animal health and monetary impacts from black flies.
662

Toxicogenetic Studies in Drosophila: Using Fruit Flies to Study Arsenic Toxicity

Muñiz Ortiz, Jorge G. 17 April 2009 (has links)
No description available.
663

Use Of Fly Ash As Eco-Friendly Filler In Synthetic Rubber For Tire Applications

Ren, Xianjie, ren 10 June 2016 (has links)
No description available.
664

Performance Evaluation of Wet Metal Plate Electrostatic Precipitator

Bharmal, Huzefa A. January 2005 (has links)
No description available.
665

Fly-ash particulates analysis of no. 6 fuel oil coal-oil-water slurries in a small industrial boiler

Zronek, Steven C. January 1986 (has links)
No description available.
666

The Impact of Curing Temperature on the Hydration, Microstructure, Mechanical Properties, and Durability of Nanomodified Cementitious Composites

Dan Huang (13169919) 28 July 2022 (has links)
<p>The study focused on examining the effects of using nanoadditives (nano-TiO2 and colloidal silica) on the hydration kinetics, microstructure, mechanical properties, and durability of concretes, especially those containing fly ash and slag and cured at low (4°C) temperature. </p> <p>The results of the Vicat and isothermal calorimetery (IC) tests suggest that the addition of nano-TiO2 accelerates the hydration process of pastes. In addition, the results of the thermogravimetric analysis (TGA) indicated that the addition of nano-TiO2 increased the amount of hydration products in the pastes, with more notable increases observed in fly ash pastes. Moreover, X-ray diffraction (XRD) results revealed that the addition of nano-TiO2 reduced the mean size of calcium hydroxide (CH) crystals.  </p> <p>The interfacial transition zone (ITZ) of concretes with nano-TiO2 was found to be less cracked and less porous when compared to that of concrete without nano-TiO2. Furthermore, the energy dispersive X-ray (EDX) analyses of the outer hydration products around partially hydrated cement particles in fly ash concretes with nano-TiO2 revealed reduction in the values of Ca/Si atomic ratios when compared to the reference fly ash concrete. The image analysis results of the concrete air void system indicated slightly reduced air content, increased specific surface area (SSA), and decreased spacing factor (SF) in concretes with added nano-TiO2. </p> <p>The addition of nano-TiO2 was also found to enhance the compressive and flexural strengths of mortars and concretes. Nano-TiO2 also improved the resistivity and formation factor values of concretes containing fly ash. Moreover, the total volume of pores, as well as the values of water absorption, were also reduced as a result of addition of nano-TiO2. This was true for all types of concretes (i.e., with or without SCMs). Finally, the use of nano-TiO2 seemed to be more beneficial with respect to improving the scaling and freeze-thaw resistance of fly ash concretes compared to cement-only and slag concretes. </p> <p>Concretes with added nanosilica (colloidal silica) also developed higher compressive and flexural strengths when compared to reference concrete. Moreover, the total pores and permeability of concretes decreased due to the addition of nanosilica while the improvement in scaling resistance of these concretes was only slight. Furthermore, concretes with nanosilica were found to have higher percentage of finer air voids compared to reference concretes. Finally, the ITZ of concretes with nanosilica was found to have fewer defects and cracks compared to the reference concrete. </p> <p>In summary, this dissertation presents the results of a study on the multi-scale behavior of nanomodified concretes with and without SCMs cured at both room and low temperatures. Knowledge gained from this study would be helpful in developing concretes with denser and less porous microstructure, a more refined and better-distributed air void system, improved strength, reduced permeability, and enhanced scaling and freeze-thaw resistance, especially in cases when involving the use of SCMs and exposure to low early-age temperatures.</p>
667

<b>UNVEILING THE EFFECTS OF DIETARY MODULATIONS ON AVIAN COCCIDIOSIS: INSIGHTS INTO GUT HEALTH AND GROWTH DYNAMICS</b>

Jing Yuan (18625108) 28 May 2024 (has links)
<p dir="ltr">For this dissertation, two experiments were conducted to evaluate the effects of a multienzyme mix and partially defatted black soldier fly larvae meal on chicken coccidiosis, focusing on growth performance, intestinal health, and microbiota dynamics. Experiment 1 examined the growth performance, nutrient utilization, microbiota modulations, and other gut health-related indicators of broiler chickens under coccidia challenge, with dietary supplementation of multienzyme, including phytase, xylanase, β-glucanase, amylase, hemicellulase, and pectinase. Ross 308 broilers were assigned to 4 treatments in a 2×2 factorial arrangement comprising of 0 or 50 g·kg-1 multienzyme and oral challenge with PBS or mixed Eimeria spp. oocysts (250,000 E. acervulina, 50,000 E. maxima, and 50,000 E. tenella). Multienzyme reduced (P < 0.05) Eimeria-induced loss in feed efficiency and nutrient utilization, partially explained by reduced decrease of b0,+ amino acid transporter in jejunum. Multienzyme suppressed (P < 0.05) the overexpression of interleukin-8 in the duodenum and jejunum and ameliorated (P = 0.05) the decreased expression of antioxidant heme oxygenase 1 in ileum induced by Eimeria infections. Multienzyme facilitated (P < 0.01) the bloom of short-chain fatty acid-producing and fiber-degrading microbes. The study concluded that multienzyme supplementation partially alleviated the adverse effects of Eimeria infections through various mechanisms, including enhanced nutrient utilization, reduced local inflammations, and restoration of microbial homeostasis. Experiment 2 investigated the growth dynamics, nutrient assimilation, and gut health responses of broiler chickens under coccidia challenge, with dietary supplementation of partially defatted black soldier fly larvae meal (pBSFLM) with increasing concentrations of 0, 60, 120 g/kg. During the infection phase (from d 13 to 19), interactions between Eimeria and pBSFLM revealed significant associations with gain to feed ratio (G:F) (P < 0.05) and cecal interferon-γ (IFN-γ, P < 0.05), while showing tendencies for crypt depth (P = 0.088) and cecal acetate concentration (P = 0.06). The incremental inclusion of pBSFLM demonstrated a negative effect on the G:F and the generation of IFN-γ and acetate in the ceca during coccidia challenge. Conversely in the non-challenged birds, the impact of dietary pBSFLM varied from neutral (e.g. G:F) to potentially advantageous (e.g. acetate). Challenged broilers exhibited decreased (P < 0.01) BW, feed intake (FI), G:F, as well as the apparent ileal digestibility (AID) and total tract nutrient utilization (ATTU) of DM, gross energy (GE), and nitrogen (N). Eimeria challenge led to reduced (P < 0.01) serum carotenoid concentrations, increased (P < 0.01) ileal crypt depth (CD), and an increase in the generation of branched-chain fatty acids, specifically isobutyrate (P = 0.059) and isovalerate (P < 0.05) in the ceca. Dietary pBSFLM addition caused a linear reduction (P < 0.05) in BW, FI, G:F, and N utilization. Furthermore, a tendency (P < 0.06) was observed where pBSFLM linearly decreased the villi height: CD ratio and reduced goblet cell density in the villi. Results from this experiment reveal that higher levels of pBSFLM supplementation, especially at 12%, had detrimental effects on growth, ileal morphology, cecal acetate production, and downregulated the expression of key cytokines in response to coccidia infection. In summary, these studies shed light on the multifaceted effects of dietary interventions on Eimeria infections in broiler chickens, with a specific emphasis on growth, nutrient utilization, and indicators of gut health.</p>
668

Properties of cementless mortars activated by sodium silicate.

Yang, Keun-Hyeok, Song, J-K., Ashour, Ashraf, Lee, E-T. 09 1900 (has links)
yes / The present paper reports the testing of 12 alkali-activated mortars and a control ordinary portland cement (OPC) mortar. The main aim is to develop cementless binder activated by sodium silicate powder. An alkali quality coefficient combining the amounts of main compositions of source materials and sodium oxide (Na2O) in sodium silicate is proposed to assess the properties of alkali activated mortars, based on the hydration mechanism of alkali-activated pastes. Fly ash (FA) and ground granulated blast-furnace slag (GGBS) were employed as source materials. The ratio of Na2O-to-source material by weight for different mortars ranged between 0.038 and 0.164; as a result, alkali quality coefficient was varied from 0.0025 to 0.0365. Flow loss of fresh mortar, and shrinkage strain, compressive strength and modulus of rupture of hardened mortars were measured. The compressive strength development of alkali activated mortar was also compared with the design equations for OPC concrete specified in ACI 209 and EC 2. Test results clearly showed that the flow loss and compressive strength development of alkali-activated mortar were significantly dependent on the proposed alkali quality coefficient. In particular, a higher rate of compressive strength development achieved at early age for GGBS-based alkali-activated mortar and at long-term age for FA-based alkali-activated mortar. In addition, shrinkage strain and modulus of rupture of alkali-activated mortar were comparable to those of OPC mortar.
669

An Invasive Fruit Fly, Bactrocera dorsalis (Tephritidae), on Mango in Senegal: Impact on Mango Crop Production and Value, Marketing Practices, and Management

Balayara, Assa 12 July 2016 (has links)
The oriental fruit fly, Bactrocera dorsalis Hendel, is an economic tephritid that invaded Senegal in 2004 (Vayssieres et al. 2011). This work determined 1) Impact of B. dorsalis on mango crop production and value, and marketing practices, 2) Effect of neem and kaolin on its behavior and development (laboratory and field), and 3) Effect of treated soil with neem seed cake (NSC) and neem seed powder (NSP) on the larval-pupal survival and development (laboratory and field). Results revealed crop value (price/kg) was associated with infestation levels. P<0.0001, crop value decreased in highly infested orchards. Southern Orchards were heavily infested than northern orchards. Early harvest, orchard sanitation, decreasing the purchase quantity, sorting infested mangoes and lowering prices were strategies used by growers and traders. Laboratory bioassays showed females landed and spent time on fruit identically on control and neem. On kaolin there were fewer landings and less time spent. P<0.0001, mean pupae was higher in control than in treated mangoes. In the field, percent of infested mangoes was higher in neem than in control and kaolin. However, the number of emerged flies was higher in the control than in either the neem or kaolin-treated fruit. Treated soil with NSC and with NSP did not have effect on pupation; all larvae pupated in the lab. However, treated soil decreased significantly the number of emerged flies. In the field, there were no significant differences between untreated and treated soil in number of emerged flies. / Master of Science in Life Sciences
670

An assessment of the environmental effects of coal ash effluents using structural and functional parameters of aufwuchs communities

Nicholson, Richard B. January 1982 (has links)
A site-specific artificial stream system receiving selected levels of fly ash, heavy metals, or sulfates was compared to a natural stream (Adair Run) influenced by effluent from the fly ash settling basin at Glen Lyn, Virginia. Aufwuchs communities colonizing glass microscope slides were monitored for dry weights, ash-free dry weights, chlorophylls, ATP, and 14-carbon and 35-sulfate assimilation rates. Productivity appeared to be enhanced in Adair Run due to increased concentrations of sulfates (150 mg/l), and temperature (delta T=4. 5 C) in the ash basin effluent. A recovery response was observed following termination of basin operation. Artificial streams receiving selected concentrations of fly ash at low TSS (8.0-25 mg/l) exhibited no inhibition for all parameters except chlorophyll a and ATP. Higher levels (80-100 mg/l) depressed all aufwuchs parameters except AFDW within six days. Six heavy metals (Cd, Cr, Cu, Ni, Pb, Zn), when collectively pumped into artificial streams at concentrations modeling the ash basin effluent effectively lowered productivity parameters. This was followed by a slow recovery response. Aufwuchs demonstrated an ability to bioconcentrate heavy metals from ambient water. Streams dosed with sulfates demonstrated a stimulation response at concentrations modeling the Adair Run system. Current U.S. EPA effluent guidelines for fly ash (30 mg/l maximum weekly average; 100 mg/l maximum) are evaluated concerning the degree of protection afforded primary producers of aquatic receiving systems. / Master of Science

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