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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.
121

Investigation of ecological behavior of two Coccinellidae beetle adults for biological control

Adedipe, Folukemi Ebunoluwa. January 2009 (has links)
Thesis (M.S.)--West Virginia University, 2009. / Title from document title page. Document formatted into pages; contains vii, 60 p. : ill. (some col.). Includes abstract. Includes bibliographical references.
122

Effects of insect growth regulators on the bionomics and control of the horn fly, Haematobia irritans (Linnaeus)

Greer, Norman Ivan, January 1975 (has links)
Thesis--University of Florida, 1975. / Description based on print version record. Typescript. Vita. Includes bibliographical references (leaves 97-103).
123

The identification and use of semiochemicals for the control of the maize weevil, Sitophilus zeamais (Motschulsky) in Nigeria

Ukeh, Donald A. January 2008 (has links)
Thesis (Ph.D.)--Aberdeen University, 2008. / Title from web page (viewed on Apr. 14, 2009). Includes bibliographical references.
124

Natural predators and parasites in relation to chemical control of the cabbage maggot, Hylemya brassicae (Bouche), in Wisconsin

Pitre, Henry N. January 1965 (has links)
Thesis (Ph. D.)--University of Wisconsin, 1965. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliography.
125

Interactions between cacti and cactus-feeding insects causes and consequences of variation /

Miller, Thomas Edward. January 1900 (has links)
Thesis (Ph.D.)--University of Nebraska-Lincoln, 2007. / Title from title screen (site viewed Aug. 1, 2007). PDF text: 230 p. : ill. (some col.) UMI publication number: AAT 3255893. Includes bibliographical references. Also available in microfilm and microfiche formats.
126

An assessment of two passive trap methods to sample naturally occuring bees at three different sites on the Delmarva Peninsula

Stragar, Catherine E. January 2007 (has links)
Thesis (M.S.)--University of Delaware, 2007. / Principal faculty advisor: Dewey M. Caron, Dept. of Entomology & Wildlife Ecology. Includes bibliographical references.
127

Ecdysteroid biosynthesis and its inhibition

Hargreaves, Iain Parry January 1994 (has links)
No description available.
128

Protection from beetle-predation in cochineal insects (Dactylopiidae : Homoptera)

Morrison, John Frederick January 1984 (has links)
From introduction: In South Africa the native ladybird beetle Exochomus flaviventris Mader feeds on the introduced cochineal insect Dactylopius opuntiae (Cockerell) (Pettey, 1943, 1946, 1948; Geyer, 1947 a, b; Pettey and Marais, 1950). It has also been reported to feed on Dactylopius austrinus Lindley (Geyer, 1947 a; Pettey, 1948), but this appears to occur rarely in the field (H.G. Zimmermann and H.G. Robertson pers. camm. ; Appendix 1 ). This thesis attempts to determine why E. flaviventris feeds on D. opuntiae in the field but not on D. austrinus.
129

Observations on the operation of two light traps at Manhattan during two seasons and an analysis of the catch of twenty-five species of Lepidoptera

Nonamaker, Harold Leroy January 1933 (has links)
Typescript, etc.
130

The development of a commercial production process for p-menthane-3,8-diol

Rust, Nico January 2009 (has links)
The synthesis of p-menthane-3,8-diol via the acid-catalyzed cyclization of citronellal in a dilute aqueous sulphuric acid medium was investigated using conventional batch and continuous systems in order to develop a commercial production process for said p-menthane-3,8-diol (PMD). The batch studies conducted during the first part of this study showed that the formation of PMD from citronellal occurs via an intra-molecular Prins reaction that results in the formation of both the desired PMD product, as well as the partially hydrated isopulegol. It was shown that the formationof the by- product, PMD-acetal, results from the reaction between an intermediate, 5-methyl-2- isopropylcyclohexanol, and the citronellal starting material, and not from the reaction between PMD and citronellal as previously reported. Kinetic studies confirmed the existence of a complicated kinetic model. The formation of PMD from citronellal displayed typical pseudo first order kinetics up to conversions of 70 after which the kinetic model becomes complicated as the result of the establishment of quasi equilibrium reactions between PMD and isopulegol (dehydration of PMD and hydration of isopulegol) and between PMD the PMD-acetal, both systems being acid catalysed. The PMD-acetal formation reaction appears to be second order with respect to PMD. Scale-up studies of the batch process to 30L and 50L scales showed that it would be extremely difficult to limit the level of PMD-acetal formation below the desired level of 1 percent, even if citronellal conversions are restricted to about 50 percent. During studies conducted on a commercially availablemicro-structured organic synthesis plant (OSP) it was shown that it is possible to perform the PMD reaction as a continuous process. The results obtained showed that the use of a micro-mixer such as the caterpillar micro-mixer did not provide enough residence time in order for desirable conversions (- 40 percent) to be obtained. By combining themicro-mixer with delay-loops of different thicknesses and lengths, and using increasing reaction temperatures, it was shown that the conversion of citronellal could be improved to some extent, but compared poorly to the expected conversions for a well-stirred batch reactor. By packing selected delay loops with inert SiC particles, improved mass transfer was observed between the organic and aqueous phases as reflected in the increased conversion of citronellal. Using the observations that were made during the use of the OSP, a continuous-flow, tubular reactor system was designed and constructed. Advanced statistical techniques were used to investigate the effect of variables such as temperature, acid concentration, reactor length, flow rate and the organic to aqueous ratio on the rate and selectivity of the reaction. Mathematical models were derived for citronellal conversion, yield of PMD and yield of PMD- acetals, and used to predict the concentrations of citronellal, PMD and PMD-acetals at set experimental conditions. The results obtained showed that it was possible to obtain a product which approached desired specifications.Downstream processing of the PMD reaction mixture as it exits the reactor requires phase separation and neutralization of the acid catalyst solution, followed by further work-up to recover unreacted starting material and intermediates for recycle back to the synthesis reactor, followed by purification of crude PMD to the desired specification. The study showed that neutralization, prior or after phase separation, does not affect the selectivity of the PMD to such a great extent, but does influence the relative conversion due to extended contact of the catalyst with the organic phase after the reaction is terminated. Recovery of unreacted citronellal and isopulegol could be achieved by a simple vacuum evaporation step, which may either be carried out in a batch manner using traditional distillation equipment, or in a continuous process using wiped-film (short path) techniques. It was also shown that selective crystallization of PMD from the crude product mixture by addition of a solvent, such as heptanes or hexane proved to be the best way of achieving the desired product specification.

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