Thesis (Ph. D.)--University of Nevada, Reno, 2007. / "August 2007." Includes bibliographical references. Online version available on the World Wide Web.

Thesis (M.A.)--University of Delaware, 2008. / Principal faculty advisor: Delphis F. Levia, Dept. of Geography. Includes bibliographical references.

Thesis (M.Sc.). / Written for the Dept. of Natural Resource Sciences. Title from title page of PDF (viewed 2009/06/29). Includes bibliographical references.

Thesis (master's)--Sveriges lantbruksuniversitet, 2007. / Includes bibliographical references (p. 34). Also issued electronically via World Wide Web in PDF format.

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Bark beetles are major pests of pine forests in North America that can inflict considerable damage and cause severe economic loss. The checkered beetle Thanasimus dubius Fabricius (Coleoptera: Cleridae), an abundant predator in the Eastern USA and Canada, has been suggested to influence the dynamics of several bark beetles, including the economically important southern pine beetle (SPB), Dendroctonus frontalis Zimmermann (Coleoptera: Curculionidae). Because of the importance of T. dubius in pine forests, I studied several aspects of T. dubius biology including both its chemical and dispersal ecology. I first present an experiment that was conducted to improve the rearing system of T. dubius so that sufficient numbers of predators could be produced more efficiently for both behavioral and ecological studies. Improvements to the rearing method potentially could be achieved by adding a preservative to increase the shelf-life of the diet used to feed larval T. dubius thereby allowing feeding intervals to be extended. To evaluate this, I added sorbic acid, a preservative, to the larval diet at three different concentrations (0, 0.1 and 0.2%) and for two different intervals between feedings (2-3 vs. 5 days). Additionally, I measured potential deleterious effects of this preservative on predator performance (i.e., female fecundity). I then assessed the effect of this predator on SPB survival by releasing newly hatched T. dubius larvae at several densities (0, 50 100, and 200) on pine logs infested by SPB. I also studied the chemotactic response of this predator toward various volatiles such as prey pheromones or tree volatiles in a wind tunnel. I developed a method that associated upwind flight behavior and antennal behavior to quantify the relative attractiveness of each tested source of chemical. I then conducted three experiments to investigate the ability of individual T. dubius to respond to different prey olfactory signals (bark beetle pheromones) and assess their potential for learning. First, I examined individual predator preferences toward three major prey pheromones (ipsenol, ipsdienol, and frontalin) in a study that combined a mark-release-recapture experiment with a field choice test. I also measured the responses of individual wild T. dubius in a wind tunnel, which allowed the testing of a wider range of semiochemicals (frontalin, ipsenol, ipsdienol, sulcatol, and α-pinene). A final wind tunnel experiment tested the ability of naive predators to learn two prey pheromones, frontalin and ipsenol, that were presented alone or associated with a reward. In the last chapter, I quantified the dispersal of this predator and its behavior along an edge separating a pine forest from a non-suitable habitat. I analyzed T. dubius distribution and movement in the field relative to its bark beetle prey Ips grandicollis Eichhoff (Coleoptera: Curculionidae) and to the root feeder Dendroctonus valens LeConte (Coleoptera: Curculionidae). These three insects are associated with the phenomenon of red pine decline in the Great Lakes area. Thus, understanding the relative pattern of movements of these three beetles could provide considerable knowledge on the spatial and temporal progression of red pine decline by, for instance, assessing the connection between existing pockets. I estimated the dispersal quantiles for this predator relative to its bark beetle prey and determined whether dispersal behavior was relatively homogeneous (one kind of disperser) or heterogeneous (two kinds). In a second part, I sampled the abundance of T. dubius, I. grandicollis, and D. valens along transects set between a matrix area constituted by a clearing and a habitat zone composed of red pine forest. I further developed a diffusion model, including a constant k (corresponds to the ratio of densities along the edge), that permits characterization of beetle behavior around the boundary. Studies developed in the present dissertation, therefore, investigated several aspects of T. dubius ecology: predation on SPB, ability to respond to an olfactory signal, and dispersal traits. I first showed that augmentation with larval T. dubius can successfully reduce the SPB ratio of increase in infested pine logs. I also developed a system of rearing T. dubius that was more efficient and could allow larger numbers of predators to be produced. Sorbic acid did not reduce adult lifetime or size but did affect female fecundity (20 - 40% reduction). Increasing feeding time interval to 5 days (instead of 2-3 days) improved the efficiency of the system, even when sorbic acid was not added in the diet. Wind tunnel experiments present a methodology that could enable future quantification of the relative attractiveness of various semiochemical treatments. I identified a particular antennal behavior, which I called "stand up antennal" that was typically produced when the insect was attracted to a semiochemical. The choice tests in the field and the wind tunnel experiment using wild adults both showed that T. dubius individuals are generalists that are flexible in their response to a broad range of semiochemical signals (frontalin, ipsenol, ipsdienol, sulcatol, and α-pinene). I demonstrate that naive predators are more attracted toward ipsenol after having experienced conditioning with this kairomone via a reward. Finally, experiments on dispersal and edge behavior revealed that T. dubius and one of its common prey, the bark beetle I. grandicollis, exhibit a different pattern of movement within red pine stands and surrounding habitats. First, adult T. dubius can disperse substantially further (50% dispersed beyond 1.54 km) than I. grandicollis adults (50% dispersed beyond 0.13 km). Second, T. dubius was highly affected by the presence of an edge, showing a step-like pattern with very predators caught in unsuitable areas. Conversely, the behavior of I. grandicollis was less limited by such a boundary. As with T. dubius, the root colonizer D. valens showed a strong edge behavior that was characterized by avoiding matrix zones.

Abstract The objective of this work was to study the effect of adjustable process parameters on wood loss and bark removal in tumble drum debarking. The effect of capacity on the size distribution of the chips was studied in order to determine the optimal capacity for both the debarking and chipping sub-processes. The final aim was to propose a control strategy to optimise the processes by adapting their parameters according to the quality of the raw material. When the research started, earlier automation systems had focused on keeping the process alive, and economic values such as wood loss were not considered important. The process is usually controlled manually and shifts have different ways to manage it, which are based on trial and error. Bark removal in chemical pulp mills is usually higher than the values recommended in the literature, which in turn causes log breaking in the drum and increases wood loss. Even a small reduction in wood loss could have a substantial financial outcome. The lack of raw materials some time ago and the recession nowadays have highlighted the importance of more efficient log use. Data survey techniques were employed to reveal the interactions between drum variables from noisy measurements. Wood room data were analysed by modelling and deriving conclusions from the resulting parameters. In addition, log breaking and the size distribution of the chips were analysed under different process conditions. A pilot-scale drum was used to study residence time and the mechanical abrasion of logs. The results of this work indicated that the ratio of the volume of logs in the drum to capacity determines the residence time of the logs in the drum. Other variables influence the volume of logs in the drum, which together with capacity determine the residence time of logs in the drum, which affects wood loss and bark removal. The effect of capacity on the size distribution of the chips was not unambiguous, however, and it was therefore recommended to operate wood room at high capacity, because this reduces wood loss and increases annual production. The proposed control strategy adapts the residence time of logs in the drum to the quality of the debarked raw material by controlling the position of the closing gate. In addition, the control strategy adjusts the rotating speed of the drum using an open loop control. The results can be used to optimise the wood room process parameters. If the problem in wood room is excessive debarking, the residence time of the logs can be reduced and the rotating speed of the drum lowered. In this way the logs will be damaged less and wood loss will be reduced. Bark removal requirements in mechanical pulp mills are high, and the process parameters can be adapted to avoid problems in the subsequent processes due to excessive bark.

This diploma thesis deals with the objective methods of audio-signal qualification. In detail have been described algorithms to the reader which are used in individual methods. Individual methods are analyzed from computational intensity, ability to predict precisely subjective quality of audio-signals, point of view. There have been described basic variables by which audio-signals are described in further parts of this thesis. Second part has been dedicated to theoretical description of individual methods – their advantages and disadvantages and practical forms of usage. Third part has been dedicated to implementation of two chosen methods in graphical interface of MATLAB program. All the functions are described in detail which these applications offer. In the last part of the thesis there are in detail described results obtained by practical testing of audio-signals with different character in created applications and evaluated quality of reached results as an outcome.

The pine engraver beetles (~ spp.:Coleoptera:Scolytidae) may be serious pests depending on certain prerequisite conditions. In their secondary or "normal" role they breed in slash and damaged, dying, and dead trees. The broods emerging from these sources normally attack similar material. When such material is scarce due to cessation of cutting operations in mid-season or when conditions are especially favorable for brood development, an excess of beetles is often produced which, due to the lack of more suitable material, attack healthy trees. Repeated attacks cause these trees to succumb and die. When normally healthy trees are weakened by fire, flood, defoliation, drought, stagnation, etc., then they become more acceptable host material for successful engraver attacks. When the production of a very large number of beetles in "normal" breeding material coincides with physiological stress in "healthy" trees, then population explosions can occur. When large numbers of beetles and low host vigor do not coincide, spot kills cornnon1y occur. According to Thatcher (32), spot kills, although not conspicuous, add up to large volumes of timber loss each year. / Ph. D.