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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.

Proton radiative capture to 13N in the region of the second harmonic giant dipole resonance collective excitation

Zucchiatti, Alessandro 18 August 2014 (has links)
This work embraces the measurement of angular distributions and excitation functions for proton radiative capture to the ground and excited states of 13N, in energy steps from E p = 40 to E p = 52MeV. Legendre polynomial fits to the angular distributions are made and the energy variation of Legendre coefficients is established for several (p, 7 ) transitions involving states up to an excitation energy of 15 MeV. The polynomial coefficients are explained by large dipole-quadrupole interference effects, particularly interesting at excitation energies corresponding to twice (£„ ~ 46 MeV) the centroid value of the ground state based Giant Dipole Excitation. Broad resonances are found in the (p,7o) &nd the (p, 72+3) channels, which involve final states that are members of the same rotational band and therefore should present very similar internal structures as the almost equivalent Legendre coefficients substantiate. For other excited states similar trends have been found although within limits imposed by larger experimental errors. The 2hw -+ Ihuj transition is found largely superimposed on inelastic proton scattering channels, contrary to what was established in previous experiments. Upper limits for the excitation functions are extracted and only for the highest measured energy point are the two contributions clearly separated. This reasearch program is based on a newly-developed anti-coincidence large-volume scintillation spectrometer designed by means of a Monte Carlo simulation code. Sp jcific tests performed with Tandem accelerator beams, and routine application at higher energies, demonstrate the excellent correspondence of the design expectations with the performance as measured, for this spectrometer.

Feasibility study of air carbon capture and sequestration system

Ismail, Mohamed Ashraf Unknown Date
No description available.

Improvement of air quality through the uptake of particulate pollutants by trees

Beckett, Kevin Paul January 2000 (has links)
No description available.

An Examination of the Capture Theory of Regulation: The Development of a General Empirical Model and its Application in Two Case Settings

Becker, Gilbert January 1983 (has links)
This dissertation provides an empirical analysis of the theory of regulatory capture. Distinction is made between simpler perceptions of the occurrence of regulation, and the theory of regulation presented by Sam Peltzman. The basic Peltzman thesis is that regulation is determined by a rational political support maximizing legislator. The focus of this study is on investigating the accuracy of Peltzman' s theory. To date, there does not exist a good empirical model of regulatory capture which can be used to test this theory in a broad array of case settings. A principal feature of this dissertation is the development of such a general model. / Thesis (PhD) — Boston College, 1983. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Economics. / Thesis advisor:

Electron trapping in metal oxides

Myers, Gus Edward, 1937- January 1971 (has links)
No description available.

Human motion synthesis from captured data

Tanco, L. Molina January 2002 (has links)
Animation of human motion is one of the most challenging topics in computer graphics. This is due to the large number of degrees of freedom of the body and to our ability to detect unnatural motion. Keyframing and interpolation remains the form of animation that is preferred by most animators because of the control and flexibility it provides. However this is a labour intensive process that requires skills that take years to acquire. Human motion capture techniques provide accurate measurement of the motion of a performer that can be mapped onto an animated character to provide strikingly natural animation. This raises the problem of how to allow an animator to modify captured movement to produce a desired animation whilst preserving the natural quality. This thesis introduces a new approach to the animation of human motion based on combining the flexibility of keyframing with the visual quality of motion capture data. In particular it addresses the problem of synthesising natural inbetween motion for sparse keyframes. This thesis proposes to obtain this motion by sampling high quality human motion capture data. The problem of keyframe interpolation is formulated as a search problem in a graph. This presents two difficulties: The complexity of the search makes it impractical for the large databases of motion capture required to model human motion. The second difficulty is that the global temporal structure in the data may not be preserved in the search. To address these difficulties this thesis introduces a layered framework that both reduces the complexity of the search and preserves the global temporal structure of the data. The first layer is a simplification of the graph obtained by clustering methods. This layer enables efficient planning of the search for a path between start and end keyframes. The second layer directly samples segments of the original motion data to synthesise realistic inbetween motion for the keyframes. A number of additional contributions are made including novel representations for human motion, pose similarity cost functions, dynamic programming algorithms for efficient search and quantitative evaluation methods. Results of realistic inbetween motion are presented with databases of up to 120 sequences (35000 frames). Key words: Human Motion Synthesis, Motion Capture, Character Animation, Graph Search, Clustering, Unsupervised Learning, Markov Models, Dynamic Programming.

A study of X and gamma rays following muon capture in 28Si

Moftah, Belal Ali January 1991 (has links)
Negative muons produced via the backward decay of pions in the M9b beam channel at TRIUMF were stopped in a ²⁸Si target. The energies of the muonic X-rays and nuclear γ-rays following the muon capture were measured in order to identify a Doppler broadened γ ray line in ²⁸A1 which is suitable for analysis in terms of a γ — ν angular correlation to determine a value for the induced-pseudoscalar coupling constant (gp ). The muon beam was also stopped in 6 other background targets ( polythene, A1, stainless steel, Cu, Pb and BGO ) and their X- and γ-ray energies have been studied so as to fully understand the backgrounds associated with such a transition. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Conversion electron and low energy gamma-ray spectrometer.

Johnson, John Richard January 1970 (has links)
A conversion electron and low energy gamma-ray spectrometer has been developed using a silicon lithium-drifted semiconductor detector. The spectrometer has a resolution of 2 Kev for 100 Kev electrons and photons under optimum conditions. The energies of these electrons and gamma-rays can be estimated to ±.1 Kev, and their intensities to within ±6% with the standard sources available. The electron capture decay of ¹⁵³Gd → ¹⁵³Eu was investigated using this spectrometer. The branching capture ratios to the 172.9 Kev, 103.2 Kev, 97.4 Kev, and 0 Kev levels of ¹⁵³Eu were found to be 11%, 39%, 39% and 11%, respectively. Possible Jπ values of ⁵ ̸₂ + or ³ ̸₂ + for the 172.9 Kev level, ⁵ ̸₂ + or ³ ̸₂ + for the 103.2 Kev level, and ³ ̸₂ -, ⁵ ̸₂ -, or ⁷ ̸₂ - for the 97.4 Kev level have been assigned. These values are in agreement with those found by other investigators. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Radiative proton capture into the nuclei pairs ¹⁶/O/¹⁷F and ²⁸Si/²⁹P at 20-80 MeV /

Rackers, Thomas William January 1984 (has links)
No description available.

Survival and Capture Efficiency of River Otters in Southern Illinois

Rutter, Andrew U 01 December 2017 (has links)
River otter (Lontra canadensis) populations in Illinois have rebounded considerably after >80 years of harvest protection and a successful reintroduction program. However, few studies of river otter ecology exist in the Midwestern U.S. where river otter numbers have increased in recent decades. Capturing study animals safely and efficiently is a critical part of wildlife research, and difficulties associated with live capture of river otters have contributed to the dearth of research on the species. Furthermore, estimating survival rates and identifying causes of mortality are important in effectively managing river otters. To address these knowledge gaps, my objectives were determine survival rates and mortality causes for river otters in southern Illinois, and to measure injury rates of river otters captured using Comstock traps. During 2014-16, I captured 42 river otters 49 times at Crab Orchard National Wildlife Refuge (CONWR) in southern Illinois. Eight river otters (3 M, 5 F) were captured in foot-hold traps during 788 trap nights (1 capture/88 trap nights), and the remaining 34 (19 M, 15 F) were captured in Comstock traps during 2,540 trap nights (1 capture/64 trap nights). I detected no significant differences in efficiency or escape rate between the 2 trap types, but Comstock traps did have higher rates for both unavailability and non-target captures. Eleven of the 20 river otters inspected for injuries received some type of injury as a result of capture in a Comstock trap (55%). The most common injury was claw loss (45%), followed by tooth fracture (25%), and lacerations (10%). The ease of setting the Comstock traps and of releasing non-target captures made them a more appealing option than foot-hold traps; however, river otters have a propensity for doing permanent damage to their teeth when live captured in Comstock traps. My study provides information on the functionality and safety of a novel live capture method for river otters. Thirty-four (16 F, 18 M) river otters were successfully radio-marked and monitored for survival for a total of 8,235 radio-days (¯x days/river otter = 242.2 ± 20.6 [SE throughout]). Two river otters (2 M) died during the period of radio-telemetry monitoring: 1 was trapped during nuisance wildlife control activities at an adjacent fish hatchery, and the other died of unknown causes. Annual survival rates were 1.0 ± 0.00 (lower confidence bound = 0.83) and 0.85 ± 0.09 for females and males, respectively, and similar between sexes (χ_1^2 = 1.7, P = 0.19). Pooled-sex breeding season survival was 0.96 ± 0.04. Trapping was the primary source of mortality over the course of my study. After radio-telemetry ended, 2 river otters were harvested by recreational trappers, at 114 (1 M) and 120 (1 F) weeks post-capture, and 1 male was killed by a vehicle collision at 52 weeks post-capture. Primary mortality sources for river otters in southern Illinois are similar to those reported elsewhere (i.e., trapping and vehicle collisions). Although I found no significant difference in survival rates between sexes, the majority of otters that died during my study were male (4 M, 1 F). As river otters occupying CONWR are protected from harvest, males may be more likely to leave the confines of CONWR, thereby putting themselves at greater risk to recreational trapping mortality. My study provides useful demographic information for Illinois’ recently-recovered river otter population.

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