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ESTIMATION OF REPRESENTATIVE TRANSMISSIVITIES OF HETEROGENEOUS AQUIFERSSteyl, Gideon 19 August 2014 (has links)
The study describes the effect of calculating a generalised mean transmissivity or hydraulic conductivity value for a region or aquifer system as it pertains to South Africa. Resource determination of an area is usually driven by the determination of the bulk flow parameters, such as hydraulic conductivity and storativity values. At this stage a decision is usually made on the basis of either maintaining the area under natural conditions (no pumping), or an abstraction (pumping) scenario is envisaged. In both instances water levels, hydraulic testing and distribution of the water resources (aquifer) are required. Since it is not possible to evaluate the total area for these parameters certain assumptions have to be made such as that an average bulk flow parameter for an area can be determined. In wide-ranging situations a simple average of observation points is assumed to be sufficient.
A systematic research approach was followed in which a three-step process was used to evaluate methods of calculating these mean values.
In the first instance a conceptual model approach was used, and all bulk flow parameters were generated by means of matrices to represent the natural system. Three typically employed mean values (arithmetic, geometric and harmonic) were calculated for two different dimensional matrices, i.e., N x N (N = 100 and 1000) with different hydraulic conductivity zones. In addition the relative difference between these hydraulic conductivity zones were steadily increased to mimic observed parameters in the field, i.e. typical hydraulic conductivity of shale (K = 0.01 m/d) versus a fracture zone (K = 100 m/d). In all instances the harmonic mean performed the best and as the number of sample sets were increased, a reduction in mean values were observed. As part of the conceptual model approach, two typically encountered scenarios were investigated, i.e. natural flow and forced gradient conditions. Under these two scenario conditions the harmonic mean performed the best to estimate the actual observed hydraulic conductivity value.
Secondly, case studies were presented which highlighted the influence of sample size on observed parameters. Additionally, the effect of the differences between the low and high hydraulic conductivity zones on the calculated mean value as a function of sample size, was also reported. In all of these case studies the harmonic mean was the closest in approximating the observed hydraulic conductivity. It is evident from this section that the number of host rock (formation) hydraulic conductivity values plays a critical part in the mean value calculation since it is general practice in South Africa not to report low yielding borehole hydraulic test values.
In the third step, the results were discussed in the context of a more general approach to the problem of calculating a regional mean hydraulic conductivity of transmissivity value. The estimation of representa-tive transmissivity values were discussed as seen from a stochastic modelling perspective as well as from the deterministic point of view. A comparison between main stream groundwater and oil industry specialists were noted in which both groups share the fundamental training but differ on the methodology of determining the observed transmissivity values. The impact of horizontal heterogeneities and different fracture networks was discussed and the influence these features have on the actual transmissivity value obtained, i.e. the influence of internal boundaries on hydraulic test data. Scale effects were also addressed from a regional perspective, with a focus on apparent scaling and the actual regional transmissivity value which should be obtained.
The findings of this study are that in essence using geostatistical methods are not advised if regional transmissivity values are required from a South African perspective. The reason behind this statement is that the distribution of transmissivity values in an area does not follow the basic precepts that are required for these methods to work. In general the values are discontinuous in distribution and statistically skewed. Furthermore, the presence of transmissivity areas or points that differ significantly in magnitude, i.e. transmissivity values which differ by more than two orders, can be located within one meter from each other. The explanation of this phenomenon is the presence of dolerite dykes, which create baked-fractured zones with exceptionally large transmissivity values compared to the extremely low transmissivity ranges of the surrounding country rock (shales, mudstone and siltstone). In addition, the lack of data concerning low-yielding or âdryâ boreholes is a major source of concern since it influences the calculated mean value to a high degree.
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EVALUATION OF ACID ROCK DRAINAGE POTENTIAL IN THE WATERBERG COALFIELDAphane, Velapi Venessa 21 August 2014 (has links)
Acid Rock Drainage (ARD) is expected to take place as soon as rock or coal that consists of sulphide minerals is exposed to the surface and comes into contact with oxygen and water. Water not only acts as catalyst, but also as a transportation medium of the yellow boy precipitates which in turn deteriorates the condition of the environment as well as water resources. Due to the long-term irreversible impact that ARD has, minimisation of this condition is an important factor to be looked at by mining companies. Worst cases have been reported by the Department of Water Affairs in and around coal and gold mines in the Witwatersrand and Witbank areas. This has brought about a necessity to explore pre-mining investigations into different lithologies to be aware of possible changes that might occur in the environment once mining commences. An evaluation of ARD was also done on the coal and rock samples to have better knowledge of what will be released in the environment and water resources as more mines are introduced in the Waterberg Coalfield..
Controlling ARD means to control the acid generating reactions of which mineralogy stands at the core of the whole reaction process. Coal deposits in South Africa largely consist of shales; mudstones, siltstones and sandstones which contain clay minerals, quartz, carbonates and sulphides. Problems that are associated with ARD (results) include decreased pH values and increased values of metals, acidity, sulphate and dissolved and suspended solids. The sulphate concentration is caused by sulphide minerals that are in the mining environment and undergo oxidation, thus bringing out the presence of sulphate.
The investigation took place in four areas, namely Resgen, Grootegeluk (Exxaro), Sasol and Sekoko. A total of 214 samples were selected from the borehole core to conduct an Acid Base Accounting (ABA) (from the interburden, overburden and coal samples), 29 samples were selected for whole rock and mineralogical analysis, and 8 selected for kinetic tests. Results from the ABA and the kinetic tests leachate were further analysed for major and trace elements using the ICP-OES (Inductively Coupled Plasma- Optical Emission Spectrometer).
ABA results show that the interburden and coal samples have a higher risk of producing acid upon oxidation when comparing it to overburden samples. They have a higher concentration of neutralising minerals that can neutralise the acid produced through sulphide minerals as oxidation takes place. In the Sasol samples, which were collected from the full succession that includes the Volksrust and the Vryheid formation, the closed Net Neutralising Potential (NNP) varied from -306.19 to 121.05 kg/tonne CaCO3. The results indicate that there is higher potential of acid production than neutralisation. Grootegeluk samples taken from the overburden showed a closed NNP that varied between -0.33 to 310.80 kg/tonne CaCO3 which classifies the samples as having more potential of neutralisation than acidification; the same case applies for Resgen with closed NNP that is between -68.96 and 57.74 kg/tonne CaCO3. Sekoko consists of the lowest number of samples that have a low risk of acid generation with more samples having a sulphide âS that is more than 0.3%.
Mineralogical analysis indicates that there is a presence of pyrite, calcite and dolomite present in accessory to minor concentration. Minerals quartz and kaolinite are found in all the samples constituted in major to dominant concentrations. Results from the whole rock analysis which correlate with mineralogical analysis were SiO2 and Al2O3 which have the highest weight percentage and is similar to the presence of quartz and kaolinite. The average Fe2O3 that is 6.73 wt.% for Sasol and 3.28 wt.% for Resgen, is higher than the average CaO and MgO which is the result of the calcite and dolomite mineral. Leachate analysis from the ABA shows that metals become more soluble as acidity increases. An increase was noted in metals such as iron, magnesium and cadmium, which is a greater threat than the acidity that results from the drainage. Further tests were carried out after the completion of the ABA analysis; kinetic tests were performed on samples that gave inconclusive NNP results. The analysis showed the long-term behaviour of different samples with the EC and pH changing over time. Samples with a lower pH continue to produce more sulphate, while calcium continues to increase until it is depleted from the samples.
The Waterberg Coalfield has not yet experienced major environmental deteriorations due to ARD; this is likely to change as more mines will be added to the area.
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COMPOSITION AND PERFORMANCE OF MULTIâLAYER LINER SYSTEMS TO INHIBIT CONTAMINANT TRANSPORT IN A FLYâASH DUMPMokhahlane, Lehlohonolo 13 May 2014 (has links)
The engineering properties of a South African class F fly ash were studied as a
potential base liner for a dry coal ash dump. In order to increase the unconfined
compression strength, lime and gypsum were added to the fly ash while also aiding
in reducing the hydraulic conductivity. Lime was added in the range of 1 to 10%
while the gypsum amounts were varied at 1% and 3% per specimen. The constant
head method was used to determine the hydraulic conductivity of compacted
specimens in the laboratory. Gypsum was observed to have more influence in
reducing the hydraulic conductivity as specimens with 3% gypsum had a more
reduced hydraulic conductivity that those with 1%. The variations in lime
percentages did not appear to reduce the hydraulic conductivity but rather displayed
higher values than fly ash specimens without additives when higher percentages of
lime were used. A fly ash admixture of 3% lime and 3% gypsum was found to have
the lowest hydraulic conductivity of 2.27 x10-9 m/s after 60 days of percolating with
brine water.
The unconfined compression strength also appeared to be more influenced by
gypsum than lime percentages as specimens with 3% gypsum obtained higher
strength values than those with 1% gypsum added. Unreacted lime was observed in
specimens with higher percentages of lime added and these specimens also
presented lower strength values. The addition of lime and gypsum was observed to
have limited the release of some trace elements from fly ash. The secondary mineral
ettringite was detected and could have possibly precipitated and captured out these
toxic elements. An attempt was also made to increase the plasticity index of fly ash
using lignosulphonate and values recommended by the South African legislative
guidelines for liner materials were obtained. The plasticity was however not retained
with subsequent leaching.
Two multi-layer liner systems were loaded under different compaction rates in
permeameter cells with fitted inflow and outflow points. The primary liners of both
systems were able to contain over 95% of leachate that percolated through a waste
layer. Compaction rate was found to affect the liners performance as primary liners with a higher compaction rate had less seepage than primary liner compacted at a
lower rate. An addition of lime and gypsum improved the overall engineering
properties of fly ash to levels accepted by the South African legislative guidelines for
a liner material that is able to line hazardous waste. Even though concentrations of
some trace elements in fly ash were reduced by addition of lime and gypsum the
level of some of these trace elements remain above the threshold set by South
African legislative guidelines and therefore remains a health and environmental
concern.
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An investigation into the physiological role of annexin A11Tomas, Alejandra January 2009 (has links)
The calcium-dependent phospholipid-binding protein annexin A11 was discovered over 25 years ago, however little is known about its function. This thesis supports a role for annexin A11 in the cell cycle and suggests an association with the microtubule network. Recent studies have implicated annexin A11 in the autoimmune disease sarcoidosis, which is further investigated in this study. A single nucleotide polymorphism within annexin A11 (R230C) was identified as a highly associated susceptibility locus for sarcoidosis. Over-expression of annexin A11WT and annexin A11R230C showed no difference in their distribution. Stimulation with ionomycin, which induces a rise in intracellular calcium, resulted in the translocation of both variants to the plasma membrane and nuclear envelope with approximately the same time course. The calcium-dependent translocation of annexin A11 is therefore unaffected by the R230C mutation. In this one aspect there appears to be no difference between the two variants, however much still remains to be investigated such as the potential extracellular roles of these variants and their function in immune cells. Much of the work in this thesis has focused on elucidating the function of wild type annexin A11, particularly during the cell cycle. During mitosis the distribution of annexin A11 is highly dynamic and localises to the mitotic spindle at metaphase and anaphase, as well as the midbody at cytokinesis. The use of methanol fixation highlighted the co-localisation of annexin A11 with the microtubule network throughout mitosis, as well as at interphase. Furthermore annexin A11 was shown to concentrate at the centrosome, again during both mitosis and interphase. Several centrosomal proteins also localise to the midbody and are key regulators of mitotic progression, supporting a similar role for annexin A11. Furthermore the centrosomal localisation of annexin A11 may serve as an ideal docking site from which it can be easily targeted throughout the cell. This study highlights the novel localisation of annexin A11 to the centrosome and the microtubule network. Furthermore these findings contribute to a growing picture for the role of annexin A11 in the cell cycle, particularly with regards to its use of the microtubule network – a feature which may also have a role in interphase cells.
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The silviculture institute : an assessment of impact /Jensen, Edward C. January 1989 (has links)
Thesis (Ph. D.)--Oregon State University, 1990. / Typescript (photocopy). Includes bibliographical references (leaves 173-178). Also available on the World Wide Web.
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The doctrinal and strategic problems of the South Australian Institute of Teachers /Vicary, Adrian, January 1982 (has links) (PDF)
Thesis (M.A.) -- University of Adelaide, Department of Politics, 1983. / Typescript (photocopy).
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The struggle for scholarly objectivity unofficial diplomacy and the Institute of Pacific Relations from the Sino-Japanese War to the McCarthy era /Sasaki, Yutaka. January 2005 (has links)
Thesis (Ph. D.)--Rutgers University, 2005. / Vita. Includes bibliographical references (leaves 536-544).
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Every Christian a missionary : fundamentalist education at Prairie Bible Institute, 1922-1947 /Enns, James, January 2000 (has links) (PDF)
Thesis (M.A.)--University of Calgary, 2000. / nbl-06 rel J.S. Mack Library copy printed from pdf available online. Includes bibliographical references (leaves 130-137).
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Town and gown : the early history of the Vancouver InstituteDamer, Eric John 05 1900 (has links)
"Town and Gown: The Early History of The Vancouver Institute" is about
the establishment and first twenty-three years of that adult education
institution. It explores the social roots that help explain the creation of The
Vancouver Institute in 1916, and follows its administrative development
until 1939. The thesis argues that the initial promoters held mutually
compatible interests that encouraged the growth of the institution, but later
promoters were forced to decide not only on the Institute's physical
location, but its symbolic association as well. The final decision was, to
some extent, a political victory for those who held a particular view of The
Vancouver Institute's proper social location. / Education, Faculty of / Graduate
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The Justice Institute of British Columbia : a structural analysisDeVries, Irwin John January 1990 (has links)
This is a case study and analysis of the Justice Institute of British Columbia, a Board-governed provincial post-secondary institute. Under contract to various provincial government ministries, the Justice Institute's five Academies and two central Divisions train municipal police, provincial court and correctional employees, fire service personnel, ambulance attendants and provincial emergency program personnel, and provide programs for professionals and the public in the areas of justice and public safety.
Although the proposed organization was conceived to meet training and educational needs that existed under the umbrella of the Ministry of Attorney-General, shortly before its formal establishment the Justice Institute was captured by the proposed Colleges and Provincial Institutes Act and now came under the jurisdiction of the Ministry of Education. Two fundamental issues emerged from the case study: jurisdictional ambiguity, involving the relation between the Justice Institute and the Ministries of Education and Attorney-General; and internal organization, involving the relation between the five Academies and the central Justice Institute administrative structure.
These emergent issues were found to be primarily structural in origin. Therefore a structural analysis was conducted, based on Mintzberg's "extended configuration hypothesis," which identifies and explains fundamental relationships among organizational design parameters and characteristics of the environment in which the organization exists. Within Mintzberg's framework the Justice Institute was identified as a divisionalized form. The case study and emergent issues were analyzed in relation to the main characteristics of the divisionalized form. In the context of jurisdictional ambiguity, it was found that decentralized internal structural relationships, and client grouping as opposed to functional grouping, may have been key factors in the survival of the Justice Institute in a period of environmental turbulence during the early to mid 1980s, and in its demonstrated effectiveness in fulfilling its organizational mission. It was further found that a strong central structure was required to stabilize the Justice Institute, particularly at times when the environment was inimical to the continued existence of the Justice Institute. It was suggested that this apparent contradiction lay at the roots of the instability of the early organization.
The study recommended that the Justice Institute recognize the weaknesses, and build upon the strengths, of the divisionalized form. Further, it found Mintzberg's extended configuration hypothesis to be an effective instrument for performing a structural analysis of an organization. / Education, Faculty of / Educational Studies (EDST), Department of / Graduate
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