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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.
11

Evaluation of a geosynthetic capillary break

Park, Kevin Donald 15 September 2005
One of the major issues in the successful decommissioning of any waste disposal system is to mitigate the spread of contaminants into the surrounding environment. In many instances this is achieved by reducing amounts of net percolation and/or oxygen diffusion into the underlying waste. An engineered cover system incorporating a capillary break is a common solution to this problem. However, traditional soil capillary breaks can often be impractical for large facilities where desirable construction materials are not readily available. The primary objective of this research is to show the initial steps in the development of a new type of geosynthetic product, namely a geosynthetic capillary break (GCB). This new product, composed of a nonwoven geotextile coupled with a fine-grained rock flour, will function similar to, and has the possibility of replacing traditional, soil capillary breaks in many applications. The specific objectives of this research are to: i) determine the pertinent material parameters of the materials used to evaluate the GCB; ii) examine one-dimensional column testing of a typical engineered soil cover system incorporating the GCB; and iii) model the cover systems to better understand current performance and predict long-term performance of the GCB. The GCB was evaluated based on the objectives outlined above. The material characterization consisted of the selection of suitable materials for the GCB, as well as the determination of their unsaturated properties. The results indicate that a geotextile-rock flour combination will develop a capillary break within an engineered cover. The one-dimensional column tests evaluated four cover systems. Soil thicknesses of 30 and 60 cm were utilized, with one column of each cover thickness incorporating the GCB. The columns were tested under both high evaporative fluxes and high infiltration rates over the course of 111 days. The measured results show that there is less moisture movement in columns that incorporate the GCB. A coupled soil-atmospheric finite element model was then used to develop a predictive model for the cover systems. The model was calibrated to the measured results from the column testing to ensure consistency. The parameters obtained from this model were used to evaluate an engineered cover system incorporating the GCB for a minesite in Flin Flon, MB. The results from the predictive modeling show that moisture infiltration is reduced approximately 80% when comparing columns with the same cover thickness. Oxygen diffusion is also reduced by 20 to 25% with the inclusion of the GCB.
12

Evaluation of a geosynthetic capillary break

Park, Kevin Donald 15 September 2005 (has links)
One of the major issues in the successful decommissioning of any waste disposal system is to mitigate the spread of contaminants into the surrounding environment. In many instances this is achieved by reducing amounts of net percolation and/or oxygen diffusion into the underlying waste. An engineered cover system incorporating a capillary break is a common solution to this problem. However, traditional soil capillary breaks can often be impractical for large facilities where desirable construction materials are not readily available. The primary objective of this research is to show the initial steps in the development of a new type of geosynthetic product, namely a geosynthetic capillary break (GCB). This new product, composed of a nonwoven geotextile coupled with a fine-grained rock flour, will function similar to, and has the possibility of replacing traditional, soil capillary breaks in many applications. The specific objectives of this research are to: i) determine the pertinent material parameters of the materials used to evaluate the GCB; ii) examine one-dimensional column testing of a typical engineered soil cover system incorporating the GCB; and iii) model the cover systems to better understand current performance and predict long-term performance of the GCB. The GCB was evaluated based on the objectives outlined above. The material characterization consisted of the selection of suitable materials for the GCB, as well as the determination of their unsaturated properties. The results indicate that a geotextile-rock flour combination will develop a capillary break within an engineered cover. The one-dimensional column tests evaluated four cover systems. Soil thicknesses of 30 and 60 cm were utilized, with one column of each cover thickness incorporating the GCB. The columns were tested under both high evaporative fluxes and high infiltration rates over the course of 111 days. The measured results show that there is less moisture movement in columns that incorporate the GCB. A coupled soil-atmospheric finite element model was then used to develop a predictive model for the cover systems. The model was calibrated to the measured results from the column testing to ensure consistency. The parameters obtained from this model were used to evaluate an engineered cover system incorporating the GCB for a minesite in Flin Flon, MB. The results from the predictive modeling show that moisture infiltration is reduced approximately 80% when comparing columns with the same cover thickness. Oxygen diffusion is also reduced by 20 to 25% with the inclusion of the GCB.
13

Field scale trials of a geosynthetic capillary break

Meier, Adam Dale Andrew 03 May 2011 (has links)
This thesis discusses the field testing of a newly-developed product, a geosynthetic capillary break (GCB). The GCB was developed for use in engineered soil covers when a cover incorporating a capillary break effect would be desirable, but the coarse-grained material (gravel or sand) is unavailable or uneconomical. Engineered soil covers aim to reduce the amount of acid generated from sulphide bearing waste by limiting the ingress of water and/or oxygen. The GCB is a geosynthetic system that is composed of a finely ground rock flour sandwiched between two nonwoven geotextiles and manufactured as a composite layer by needle punching in a process similar to the used for GCL (geosynthetic clay liner). The goal of the GCB is to recreate the capillary break that is achieved with soil layers using a geosynthetic product that is only a few centimetres thick and that can be rolled up and for transportation, The GCB concept has been demonstrated in a previous study (Park, 2005) based on laboratory column studies and computer modelling. The goal of this project was to determine the effectiveness of the GCB when applied at field scale. Four 25 square test plots were constructed at the tailings management area (TMA) of the HudBay Minerals Inc.(HudBay) mine site located near Flin Flon, MB. One plot contained 1 m of cover soil over top of the GCB (Plot A), one contained only 1 m of cover soil (Plot B), one contained 0.3 m of cover soil over top the GCB (Plot C), and one consisted of a conventional capillary break system with 1 m of cover soil over lying 0.2 m of sand. All of the plots, along with a control plot with no cover, were instrumented with water content sensors and gas sampling ports to monitor the movement of water and oxygen through the various covers. Matric suction sensors were also installed in Plots A and B to measure the water suction within the covers. A meteorological station was installed to gather climatic data which was used to develop a water balance for each of the plots. The plots were constructed and instrumented in the fall of 2005. Data was collected and analyzed until spring of 2007. Data from the water content sensors show that the GCB was effective in increasing the water content in the soil portion of the cover system. The suction sensors show that the suction across the GCB drops significantly (40 kPa versus less than 1 kPa) as compared to plots which contain no GCB. Data from the gas concentration sensors show that the plots containing capillary breaks reduce the oxygen flux into the tailings. The plots containing the GCB (Plots A and C) resulted in the lowest flux rates, followed by the sand capillary break (Plot D )and no capillary break (Plot B), respectively. This reduction in oxygen flux will reduce the amount of acid generated from waste, as oxygen is required for the creation of acid mine drainage. Overall the study demonstrated that at field scale that the GCB is effective in limiting the ingress of water and oxygen into the tailings under the observed conditions and the manufactured GCB is comparable to the performance of the previous hand constructed column tests.
14

An study on the Integration between Stock Markets in Mainland China and in Hong Kong

Chen, Tzu-yun 03 February 2010 (has links)
This study use the daily stock price of the companies simultaneously listed in China and Hong-Kong to study whether there exists a stable linkage between the stock markets in China and in Hong-Kong and whether any structural break happened. The sampling period is from July 1st, 2003 to July 31st, 2007. We apply Johansen¡¦s cointegration test and Hansen¡¦s instability test to investigate whether the prices of A shares and H shares are cointegrated. We also apply Chow test and Quandt-Andrews test to study the potential structural break caused by the change of China¡¦s exchange policy. Main results are following: (1) Johansen¡¦s cointegration tests report that the stock prices of 18 companies (out of 29 companies) are cointegrated. (2) Hansen¡¦s instability tests report more companies¡¦ stock prices are cointegrated. (3) Chow tests reports that the relation between stock prices of A shares and H shares may has a structural break in 20 companies when RMB starts to appreciate. (4) The stock prices of some companies, whose stock prices were not cointegrated during the full sampling period, were cointegrated after structural break. Compared to previous literature, we find that the link between the stock markets in China and Hong-Kong become stronger as the reform of China¡¦s financial market is deeper.
15

The application of a decision rule for feed storage

Hirshfeld, Theodore Benjamin Alexander January 1981 (has links)
No description available.
16

Trait self-esteem moderates the effect of initiator status on emotional and cognitive responses to romantic relationship dissolution

Waller, Katherine L., 1978- 18 July 2007 (has links)
Romantic relationship dissolution has been implicated in the onset of mood disorders (Monroe et al.,1999; Overbeek et al., 2003). It is therefore imperative that researchers and mental health professionals have an understanding of the factors that contribute to dysfunctional responses so as to assist vulnerable individuals with developing healthy strategies for coping with relationship dissolution. Prior research on the relationship between initiator status (i.e., who ended the relationship) and subsequent emotional distress has been mixed, with multiple researchers finding that a person's level of distress was unrelated to whether he or she ended the relationship. I hypothesized that the effect of initiator status on post-break-up distress would vary as a function of trait self-esteem such that individuals with low self-esteem would experience more distress after being rejected by their partners, whereas individuals with high self-esteem would be no more distressed after a rejection than after acting as the rejecter. I tested this hypothesis using two designs. First, I used a prospective, naturalistic design in which university students were assessed for emotional responses following the dissolution of their romantic relationships. Those who had self-reported lower trait self esteem at the outset of the study experienced higher levels of break-up-specific distress. On the other hand, those who had reported higher trait self-esteem did not exhibit differing distress levels as a function of who ended the relationship. This pattern was replicated in a laboratory design in which university students imagined breaking up with their partners. Participants with low trait self-esteem experienced more negative mood, reported lower state self-esteem, and evaluated themselves more negatively after a scenario in which they were rejected as compared to a scenario in which they rejected their partners. Participants with high self-esteem did not differ on any of these variables as a function of rejection condition. Results are discussed in terms of the theoretical implications for understanding self-esteem processes and the effects of romantic rejection. Implications for interventions for individuals with low self-esteem who are coping with romantic rejection are also explored. / Thesis (Ph.D, Psychology) -- Queen's University, 2007-07-12 12:36:26.478
17

Dam-break flows as agents of sediment transport

Emmett, Matthew Unknown Date
No description available.
18

On C^1 Rigidity for Circle Maps with a Break Point

Mazzeo, Elio 17 December 2012 (has links)
The thesis consists of two main results. The first main result is a proof that C^1 rigidity holds for circle maps with a break point for almost all rotation numbers. The second main result is a proof that C^1 robust rigidity holds for circle maps in the fractional linear transformation (FLT) pair family. That is, for this family, C^1 rigidity holds for all irrational rotation numbers. The approach taken here of proving a more general theorem that C^1 rigidity holds for circle maps with a break point satisfying a `derivatives close condition', allows us to obtain both of our main results as corollaries of this more general theorem.
19

College students' information search behavior for spring break an exploration in the concept of specialization /

Park, Sangwon, January 2007 (has links)
Thesis (M.S.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on January 16, 2008) Includes bibliographical references.
20

The way to competitiveness of PV an experience curve and break-even analysis

Staffhorst, Martin January 2006 (has links)
Zugl.: Kassel, Univ., Diss., 2006

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