Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references. Available also from UMI/Dissertation Abstracts International.

Dissertation (PhD)--University of Stellenbosch, 2007. / Bibliography. Also available via the Internet.

Thesis (MScIng)--University of Stellenbosch, 2007. / Bibliography. Also available via the Internet.

Thesis (MScIng)--University of Stellenbosch, 2007. / Bibliography. Also available via the Internet.

Thesis (Ph.D.)--Mechanical Engineering, Georgia Institute of Technology, 2009. / Committee Chair: William Singhose; Committee Member: John-Paul Clarke; Committee Member: Kok-Meng Lee; Committee Member: Patricio Vela; Committee Member: Rhett Mayor.

Στην παρούσα διπλωματική εργασία μελετάται η συμπεριφορά ενός μοντέλου γερανογέφυρας με την επιβολή ελέγχου με ανατροφοδότηση. Σκοπός μας μια κατά το δυνατόν βελτιστοποιημένη λύση του προβλήματος των ταλαντώσεων μέσω ενός αξιόπιστου, στιβαρού ελεγκτή, που να μπορεί να επιφέρει ακριβέστερη, ταχύτερη και ασφαλέστερη μετακίνηση των υλικών. Οι ελεγκτές που χρησιμοποιούμε είναι απλοί PD και PI ελεγκτές με την προσθήκη επίσης ενός μη γραμμικού ελεγκτή που βοηθά στην αύξηση της απόσβεσης των ταλαντώσεων. Επίσης με τη χρήση ενός περιοριστή ταυτόχρονα με τους άνω ελεγκτές, εξετάζουμε την συμπεριφορά του συστήματος με φραγμένη είσοδο. Ακόμα γίνεται αναφορά στους σύγχρονους τρόπους οδήγησης και πέδης AC και DC συστημάτων. / This diploma thesis forms a study on the behavior of an overhead crane after the implementation of o closed loop control law. Our goal is an optimized solution for the oscillation problem through a reliable, robust controller, who will be able to move cargos with precision, velocity and enhanced safety. The controllers used are simple PD and PI controllers with the addition of a nonlinear controller who will assist in raising the dumping value of the system. A limiter paired with the controllers above will help us evaluate the behavior of our system under a bound drive. There is also a citation of the current high-end drive and break solutions on AC and DC crane systems.

This dissertation is a practical investigation into the magnitude of the vertical and lateral forces exerted, by electric overhead travelling cranes, on their supporting structures during operation. The method of measuring the forces and the equipment used for the actual measurements are discussed, as well as the equipment used for the processing of the recoided date. The forces measured during the experiments, executed in two stages namely controlled conditions and normal operation, are discussed under the headings of vertical forces due to the weight of the crane and lead handled, and the lateral forces due to cross travel movement, skewing of the crane and acceleration/deceleration of the crane. It is shown that the vertical misalignment of the rails, together with the stiffness of the crane structure, has a large influence on the magnitude of the vertical forces. Drive wheel slip, tested under controlled conditions on two E-type cranes, proved to cause high lateral forces. Comparisons are made with the existing Codes of Practice as well as with the theoretical models of crane behaviour.

The Whooping Crane (Grus americana) is among North America’s most charismatic species. Between 1938 and 2004, the population that migrates between Aransas National Wildlife Refuge (ANWR) and Wood Buffalo National Park (WBNP), grew from 18 to 217 individuals. The recovery plan objective for this endangered species is to downlist the population in 2035, but this requires interpretive assessment of population responses to environmental factors over the long term. I analyzed 27 years of banding data, 37 years of nest monitoring data, and 20 years of winter reports to estimate age-specific mortality and fecundity rates. The resulting life table yielded an intrinsic rate of increase (r) of 0.14/y, a net reproductive rate (Ro) of 6.4/y, and a mean length of a generation (G) of 13y. Path analysis of environmental factors, demographic variables (natality and mortality), and the finite rate of population increase (lambda) showed that annual mortality, temperatures from the ANWR, WBNP and at a migration stop-over in Nebraska, and pond water depth were good predictors of lambda variability. However, other environmental factors were significantly correlated: at ANWR, October- March temperature (extreme minimum and maximum), December temperature (mean and extreme minimum), November-January precipitation, and September-March freshwater inflow; at WBNP, March-September precipitation, March-May temperature, and temperatures during the September - October fall migration. The Pacific Decadal Oscillation (PDO) affected lambda indirectly through environmental factors in Nebraska and ANWR. I graphically analyzed relevant data trends from 1967 to 2004 to identify the relation between phases of PDO and environmental and demographic variables. During PDO cold phases, a synchronization of “extreme” environmental values was observed from the different regions; during warm phases extreme environmental values were scattered. Most periods of Whooping Crane population decline happened during cold phases. I developed a compartment model to represent Whooping Crane population dynamics utilizing the new data on survivorship and fecundity from banded birds. The model was capable of simulating historical population trends with adjustments in brood success and egg mortality. The model will allow future studies to test population responses to various environmental scenarios at the WBNP, during fall and spring migrations, and at the ANWR.

Thesis (M.S. in Operations Research)--Naval Postgraduate School, March 2008. / Title from PDF title screen. "March 2008." "ADA 479957." Includes bibliographical references (p. 39-40). Also available online.

Thesis (Ph. D.)--Cornell University, 1977. / Title from initial PDF page image of pt. 1 (viewed February 11, 2009). "December 1976" Includes bibliographical references (p. 161-167). Includes bibliographical references (leaves 161-167).