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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.
61

The effect of noise on the dynamics of a 2-D walking model

Campbell, Bradley Cortez 27 February 2012 (has links)
Walking models have been used to explore concepts such as energy, step variability, control strategies and redundancy in walking. A 2-D dynamic walking model was used to determine the levels of variability in gait while being perturbed. The perturbations were added in the form of randomly added noise applied at different magnitudes. The model was comprised of two equal length legs and masses at the feet and hips. The model walked on a flat surface and each step was initialed by an impulse at the swing leg. The magnitude of the impulse determined the size of the model's steps. In this study, the walker took steps with lengths that were than were analogous to humans. An attempt to offset the effect of the noise was made by adding a proportional controller to correct the errors of the applied impulse. The control equation was comprised of gain, A, and noise, [xi], term. The step length, time and speed were calculated to analyze how the model walks. It was hypothesized that the model would use a strategy similar to humans on a treadmill and follow a goal equivalent manifold. The manifold was all possible solutions of step length and step time for maintaining constant speed. Any fluctuations in step length and time would still result in constant speed. The results showed that the model's gait became more variable as noise was added. When the control was added through the gain being increased, the model steps became more variable. The model did not follow the same control strategy as humans and coordinate steps along the GEM. As the model began taking longer step lengths the step time decreased. / text
62

The Applicability of Passive Treatment Systems for the Mitigation of Acid Mine Drainage at the Williams Brothers Mine, Mariposa County, California: Bench- and Pilot-Scale Studies

Clyde, Erin Jane 30 January 2008 (has links)
The Williams Brothers Mine is located in Mariposa County, California. Surface waters from the site drain into the south fork of the Merced River and the San Joaquin River Basin. The mine was developed in the 1980s and mined intermittently until 1996. In 1998, concerns of acidic drainage at the site arose. Effluent sampling by Engineering Remediation Resources Group (ERRG) found acid mine drainage (AMD) characterized by a pH of 3.9, sulphate concentrations of 100 mg/L and low metal concentrations of 0.074, 4.60, 1.23, 0.047 and 0.133 mg/L for Cu, Fe, Mn, Ni and Zn, respectively. The aim of this research was to evaluate passive treatment system alternatives for the mitigation of the AMD to meet water quality objectives for the San Joaquin River Basin. A bench-scale study was undertaken which consisted of 3 systems treating synthetic AMD: (1) a peat biofilter to remove dissolved metals followed by an anoxic limestone drain (ALD) to increase alkalinity and pH; (2) a sulfate reducing bacteria (SRB) bioreactor followed by an ALD, in which SRB reduce sulphate to sulfides, generating alkalinity and decreasing metal concentrations via metal sulfide precipitation; and (3) a SRB bioreactor. Synthetic AMD was produced to represent AMD characteristics observed at the site. The peat-ALD system effluent pH was 6.9 and concentrations of Fe and Cu decreased to below water quality objectives with concentrations of 0.008 and 0.06, respectively. The SRB-ALD and SRB system effluents met water quality objectives for pH and Cu, Ni and Zn metal concentrations. The effluent pH for both systems was 6.5. The SRB-ALD system reduced Cu, Ni and Zn to concentrations of 0.004, 0.016 and 0.025 mg/L, respectively. The SRB system reduced metal concentrations for Cu, Ni and Zn 0.006, 0.010 and 0.027 mg/L, respectively. Based on the bench-scale study, the pilot-scale system consisted of a combined passive treatment system containing a peat biofilter, SRB bioreactor and a limestone drain. Pilot-scale testing commenced on May 23rd, 2007. To date, some metal attenuation has been observed, with average effluent concentrations of Cu, Fe, Mn, Ni and Zn equal to <0.005, 0.92, 0.45, <0.005 and 0.049 mg/L, respectively. / Thesis (Master, Geological Sciences & Geological Engineering) -- Queen's University, 2008-01-29 12:42:03.58
63

Pasyvioji leksika lietuvių–latvių ir latvių–lietuvių kalbų žodynuose / Passive Vocabulary in Lithuanian – Latvian and Latvian – Lithuanian Dictionaries

Vilkaitė, Irena 06 June 2005 (has links)
This master thesis presents analysis of passive vocabulary, i.e. historicisms and archaisms, found in Lithuanian –Latvian (1964; 1995) and Latvian – Lithuanian (1977; 2003) dictionaries. The mentioned language units are the names of old-fashioned, obsolete things, phenomena, concepts and realia. They are the only mouthpieces of such concepts and that is why we cannot manage without them when speaking about phenomena of the past. Besides, historicisms and archaisms are terms of history, ethnography, archeology and other studies related to the past. A number of this kind of vocabulary can be used in indirect meaning. Passive vocabulary in this thesis is classified and discussed in the aspects of lexis, morphology and topicality. Historicisms and archaisms of the Lithuanian and Latvian languages (formation, grammatical categories, synonymy of passive vocabulary) are compared. The work also analyses how passive vocabulary (systems of labels) is presented in different dictionaries (bilingual, thesauruses) and whether the authors of different lexicographical publications acknowledge the same historicisms and archaisms. The thesis is performed applying the comparative, descriptive – analytical and calculating methods. Lexical and morphological classifications of historicisms and archaisms support the idea that the passive vocabulary found in bilingual Lithuanian – Latvian and Latvian – Lithuanian dictionaries are very diverse and heterogeneous. Historicisms and archaisms noted in... [to full text]
64

The potential of hemp buildings in different climates : A comparison between a common passive house and the hempcrete building system

Ahlberg, Johan, Georges, Elza, Norlén, Mikael January 2014 (has links)
The aim of this bachelor thesis was to study the potential of hemp buildings in different climates. The report examines and models two different energy efficient building concepts – the more common passive house and the environmental friendly hempcrete building system. These two buildings thermal performances were then simulated and compared in different climates followed by a brief discussion about their economic and environmental impact. The simulation was performed with the energy calculating program VIP-energy v 2.1.1 with the two models located in Kiruna, Sundsvall, Malmo, Berlin and Rome to represent the different climates. Simulations for different wall sizes and a sensitivity analysis of some significant parameters were also made. The hempcrete building system showed to have a thermal performance similar to that of passive houses in more southern climates. In the north of Sweden however the hempcrete building required up to 20 % more energy than the passive house to maintain comfortable indoor temperatures. This deficit could be compensated for with hemp fibre insulation to augment the building envelope and U-value. Furthermore the hygrothermal material properties that were not included in the simulation can be expected to have a significant positive impact on hemp buildings relative thermal performance. With a passive house thermal performance, a healthy indoor environment and an economically viable and environmental friendly production process hemp building demonstrated great potential in all the fields studied.
65

Patterns of seasonal occurrence of sympatric killer whale lineages in waters off Southern Vancouver Island and Washington state, as determined by passive acoustic monitoring

Riera, Amalis 10 August 2012 (has links)
Killer whales inhabiting coastal waters of the northeastern Pacific are listed under the Canadian Species at Risk Act, which requires the identification of critical habitats for the recovery of their populations. Little is known about their distribution during the winter and what areas are important for their survival during these months. Passive acoustic monitoring is a valuable complementary method to traditional visual and photographic surveys although it has seldom been used to study killer whales and there are limitations in practice. There is a need to develop tools and protocols to maximize the efficiency of such studies. In this thesis, long-term acoustic data collected with autonomous recorders were analyzed 1) to assess the performance of two types of analysis (Manual and Long Term Spectral Averages) for detecting and identifying killer whale calls and to compare the effects of using two different duty cycles (1/3 and 2/3); and 2) to investigate the seasonal occurrence of different killer whale populations at two sites off the west coasts of Vancouver Island and Washington: Swiftsure Bank and Cape Elizabeth. Both the use of Long Term Spectral Averages and a lower duty cycle resulted in a decrease in call detection and resolution of call identification, leading to underestimations of the amount of time the whales spent at the site. A compromise between a lower resolution data processing method and a higher duty cycle (and vice-versa) is therefore suggested for future passive acoustic monitoring studies of killer whales. Killer whale calls were detected on 186 days at Swiftsure Bank and on 39 days at Cape Elizabeth. The seasonal occurrence of killer whales at Swiftsure Bank highlights its importance as a killer whale hotspot, with year-round presence of Southern Residents and British Columbia Transients, Northern Residents in spring and fall, and California Transients on rare occasions. These results support the expansion of Southern Resident’s critical habitat to include Swiftsure Bank. Temporal habitat partitioning between Resident populations was observed at Cape Elizabeth, with Southern Residents detected from January through June and Northern Residents from July to September. These results show that Northern Residents use the southern parts of their range more frequently than previously thought. Both Transient populations were frequently detected throughout the year, suggesting habitat overlapping. / Graduate
66

Constitutionalist insurgency in Finland : Finnish "passive resistance" against Russification as a case of nonmilitary struggle in the European resistance tradition /

Huxley, Steven Duncan. January 1990 (has links)
Thèse--Histoire--Helsinki, 1990. / Bibliogr. p. 267-280. Index.
67

Potentiating mechanisms of passive cigarette smoking on the pathogenesis of experimental inflammatory bowel disease /

Guo, Xin, January 2000 (has links)
Thesis (Ph. D.)--University of Hong Kong, 2000. / Includes bibliographical references (leaves 156-186).
68

The relative effectiveness of nonviolent, violent, and yielding tactics for changing the policy of an opponent

MacDowell, Peter Paxton, January 1969 (has links)
Thesis (M.A.)--University of Wisconsin--Madison, 1969. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.
69

Workers who continue to be occupationally exposed to second-hand tobacco smoke (SHS) in the UK

Talabi, Taiwo. January 2008 (has links)
Thesis (M.Sc.)--Aberdeen University, 2008. / Title from web page (viewed on June 1, 2009). Includes bibliographical references.
70

Simulation, fabrication and measurement of graphene based passive guided devices

Zhang, Xiao January 2017 (has links)
Motivated by the few work has done on the performance measurement of graphene passive devices compared to graphene active devices, several different types of passive devices are fabricated and measured. In general, the fabricated devices are divided into two parts: the DC devices and the RF devices, which based on the different electrical properties we measure in Chapter 7. For the DC devices, attention has been given to the resistance of CVD graphene that we later use in all the RF devices. The Dirac point seems only appears in the exfoliated graphene measurement, which is caused by the doping concentration difference between the exfoliated and CVD graphene. Meanwhile, the sheet resistance of graphene is calculated based on the four-point measurement. The sheet resistance of CVD graphene is around 291 Ω/sqFor the RF devices, the measurement is conducted on the two types of graphene passive devices from 0-110 GHz. The first type of graphene devices is the graphene CPW resonator. We measure the input impedances of the graphene resonators on different substrates (Si/SiO2 and GaAs) and with different graphene lengths (440 micro metre, 500 micro metre and 1415 micro metre). For the graphene resonators on Si/SiO2 substrate, the input impedance does show the resonance shift compared to the graphene-removed structure. The frequency position of the resonance that appears is consistent with the theoretical calculation result. Besides, the influence of the external conditions such as temperature on the performance of graphene resonators has been investigated. The input impedance resonance shows the shift when the external temperature varying from 40o C(313K) to 160o C (433K). This measurement is undertaken with the graphene resonator on GaAs substrate. The second type of graphene devices is the graphene CPW transmission line on Si/SiO2 substrate. The S-parameters measured from VNA reveal that graphene within the transmission line acts as the transmission channel, which is a little lossy at the microwave frequency range. The poor transmission is also partially caused by the mismatching of the parasitic impedance, as well as the substrate loss, which is verified by the comparison result between the graphene transmission line and the graphene-removed transmission line. Similarly, the concern on the signal line coupling is also eliminated by using the graphene-removed structure.

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