The first step in many mining operations is blasting, and the purpose of blasting is to fragment the rock mass in the most efficient way for that mine site and the material end use. Over time, new developments to any industry occur, and design and implementation of traditional techniques have to change as a consequence. Possibly the greatest improvement in blasting in recent years is that of electronic detonators. The improvements related to safety and increased fragmentation have been invaluable. There has been ongoing debate within the explosives industry regarding two possible theories for this. Shorter timing delays that allow interaction between adjacent shock waves or detonation waves, or the increase in accuracy associated with electronic detonators. Results exist on the improved accuracy of electronic detonators over that of electric or non-electric, but data on the relationship between the collision of dynamic stress waves and fragmentation is less understood. Publications stating that the area of greatest fragmentation will occur between points of detonation where shock waves collide exist, but experimental data to prove this fact is lacking. This dissertation looks extensively at the head on collision of shock (in the rock mass) and detonation (in the detonation column) waves with relation to fragmentation through a number of small scale tests in concrete. Timing is a vital tool for this collision to occur and is the variable utilized for the studies. Small scale tests in solid masonry blocks, 15 x 7⅞ x 7⅞ inches in size, investigated shock and detonation wave collisions with instantaneous detonation. Blocks were wrapped in geotextile fabric and a wire mesh to contain the fragments so that in situ tensile crack formations could be analyzed. Detonating cord was used as the explosive with no stemming to maintain the shock pressure but reduce the gas pressure phase of the fragmentation cycle. Model simulations of these blocks in ANSYS Autodyn looked at the stress and pressure wave patterns and corresponding damage contours for a direct comparison with the experimental investigation. Detonation wave collision in a single blast hole was found to positively influence the fragmentation and throw of the material. Mean fragment size decreased compared to tests with no detonation wave collision. Area of greatest throw occurred at the point of detonation collision where a buildup of gas pressure exited the block from one location. Head on collision of shock waves did not positively influence the muck pile. Largest fragments were located at the point of shock collision. The lack of particle velocity with relation to shock collision in previous literature could be attributed to the increased particle size here. Directional particle velocities could actually increase the strength and density of the rock at this location, decreasing the degree of fragmentation rather than increasing it.

I studied a small, enigmatic, and imperiled black bear population in south-central Florida from 2004 - 2006. Annual home ranges of males (96.0 km2) were larger than those of females (32.2 km2). Female home ranges were smaller in winter than in summer or fall. At the landscape scale, bears selected forests, scrub, and citrus, but avoided urban areas. At the home range scale, bears selected bay swamp and hardwood hammock, but avoided urban areas and grassland. Bears selected bay swamp in winter, forests and scrub in summer, and forests, scrub, and marsh in fall. The bear’s diverse diet included citrus fruit. Important foods were acorn, saw palmetto fruit, and Florida carpenter ant. The local landscape is dominated by agriculture on private lands, as opposed to large contiguous forests on public land elsewhere in Florida black bear range. Mean patch size of forests was smaller, while edge density, diversity, and evenness were higher in south-central Florida than elsewhere in the state. Diversity of forest habitat may partially account for the persistence of the black bear in this fragmented landscape. Managers should encourage private landowners to adopt practices that promote bear habitat, and focus on habitat diversity, road crossings, and statewide metapopulation structure.

Using computational methods, we have investigated the chemistry of 3-phenylpropyl radical systems. These systems are of importance to polymer chemistry as free radical additions involving these species are integral in the production of styrene-containing plastics. Although the addition reactions have been well studied, the other reaction pathways, namely f3-fragmentation and cyclization, have not been as comprehensively studied. As a result, our computational study involved 3-phenylpropyl radical systems that had been systematically mono-substituted at five positions, two on the propyl chain and three on the aromatic ring. This computational analysis consisted of calculation of optimized geometries and energies for reactants, products, and transition states, followed by examination of derived thermochemical quantities (enthalpies of activation and reaction), and critical structural parameters (transition bond lengths and bond angles) of the systems. Finally correlation of structure and reactivity of the various systems was attempted. Density functional theory (DFT) using the B3-LYP functional and the 6-31 G(d) basis set was selected as the level of theory. / Department of Chemistry

In this thesis we have utilized few-cycle pulses in the range 10-15s, to initiate CE to allow us to image the structure, dynamics, and kinetics of ionization and dissociation of triatomic molecules. We have made a series of measurements of this process for CO2 and N2O, by varying the laser pulse duration from 7 to 500 fs with intensity ranging from 2.5×1014 to 4×1015 (W/cm2), in order to identify the charge states and time scales involved. This is a new approach in CEI introducing a multi-dimensional aspect to the science of non-perturbative laser-molecule interaction. We refer to this approach as FEmtosecond Multi-PUlse Length Spectroscopy (FEMPULS). The use of a time and position sensitive detector allow us to observe all fragment ions in coincidence. By representing the final fragmentation with Dalitz and Newton plots, we have identified the underlying break up dynamics. Momentum conservation has been used to extract the correlated fragment ions which come from a single parent ion. This is achieved by considering that the total momentum of all correlated fragments must add up to zero. One of the main outcomes of our study is observation of charge resonance enhanced ionization (CREI) for triatomic molecules. In the case of CO2, we found that for the 4+ and higher charge states, 100 fs is the time scale required to reach the critical geometry RCO= 2.1Å and ӨOCO =163º (equilibrium CO2 geometry is RCO= 1:16Å and ӨOCO =172º. The CO23+ molecule, however, appears always to begin dissociation from closer than 1.7 Å indicating that dynamics on charge states lower than 3+ is not sufficient to initiate CREI. Finally, we make quantum ab initio calculations of ionization rates for CO2 and identify the electronic states responsible for CREI. Total kinetic energy (KER) has been measured for channels (1, 1, 1) to (2, 2, 2) and it was found that the (1, 1, 1) channel is not Coulombic, while (2, 2, 2) channel is very close to Coulombic (KER close to 90% of the coulombic potential). As another outcome of our study, for the case of N2O, we observed for the first time that there are two stepwise dissociation pathways for N2O3+: (1) N2O3+ → N++ NO2+ → N+ + N++ O+ and (2) N2O3+ → N22++O+ → N+ + N++ O+ as well as one for N2O4+ → N2++ NO2+ → N2+ + N++ O+. The N22+ stepwise channel is suppressed for longer pulse length, a phenomenon which we attribute to the influence which the structure of the 3+ potential has on the dissociating wave packet propagation. Finally, by observing the KER for each channel as a function of pulse duration, we show the increasing importance of CREI for channels higher than 3+.

Invasive Prosopis trees pose significant threats to biodiversity and ecosystem services in the Northern Cape Province of South Africa. Several estimates have been made of the spatial extent of alien plant invasion in South Africa. The South African Plant Invaders Atlas (SAPIA) suggested that about 10 million hectares of South Africa has been invaded. However, the rate and spatial extent of Prosopis invasion has never been accurately quantified. The objective of the study is to use Remote Sensing and Geographic Information System (GIS) techniques to: (i) reveal areas susceptible to future invasion, (ii) describe the current extent and densities of Prosopis, (iii) to reveal the spatial dynamics and (iv) establish the extent of fragmentation of the natural vegetation in the Northern Cape Province. Image classification products were generated using spectral analysis of seasonal profiles, various resolution image inputs, spectral indices and ancillary data. Classification approaches varied by scene and spatial resolution as well as application of the data. Coarse resolution imagery and field data were used to create a probability map estimating the area vulnerable to Prosopis invasion using relationships between actual Prosopis occurrence, spectral response, soils and terrain unit. Multi-temporal Landsat images and a 500m x 500m point grid enabled vector analysis and statistical data to quantify the change in distribution and density as well as the spatial dynamics of Prosopis since 1974. Fragmentation and change of natural vegetation was quantified using a combined cover density class, calculating patch density per unit (ha) for each biome The extent of Prosopis cover in the Northern Cape Province reached 1.473 million hectare or 4% of the total land area during 2007. The ability of the above mentioned Remote Sensing and GIS techniques to map the extent and densities of Prosopis in the Northern Cape Province of South Africa demonstrated a high degree of accuracy (72%). While neither the image classification nor the probability map can be considered as 100% accurate representations of Prosopis density and distribution, the products provide use full information on Prosopis distribution and are a first step towards generating more accurate products. For primary invasion management, these products and the association of a small area on a map with Prosopis plants and patches, mean that the management effort and resources are efficiently focused. Further studies using hyper-spectral image analysis are recommended to improve the classification accuracy of the spatial extent and density classes obtained in this study. / Thesis (M. Environmental Science)--North-West University, Potchefstroom Campus, 2010.

The prevalence of child sexual abuse in South Africa is alarmingly high. Child protection officials’ task is challenging due to the fact that most cases of child sexual abuse are never reported as a result of the stigma attached to child sexual abuse. This article explains the vulnerable position of the children of uniform members of the military due to the fact that one or both parents are absent from the family due to fragmentation. Two main reasons are causing fragmentation. The first reason that can be mentioned is the fact that the soldier him–/herself has decided not to relocate the family to his/her workplace. Cultural beliefs, housing crisis or other practical challenges might play a role in the parent’s decision. The second reason for fragmentation is the fact that soldiers are obliged to attend military courses or to represent their country during a peace operation on the African continent. These military obligations cause physical and emotional absence of the parental figure, which might leave the child in a vulnerable position to fall victim to child sexual abuse. Fragmentation impacts negatively on the parental relationship as well as on the safety of the child. The deployed parent often is left with no choice but to unwittingly leave the child with a harmful caretaker. The aim of the study was to establish the knowledge of parents in the military regarding child sexual abuse. The objectives of the study were: · To investigate parents in the military's basic knowledge of child sexual abuse in preventing their children from falling victim to sexual perpetrators. · To provide guidelines to military parents for preventing and recognising child sexual abuse. Data collection took place by means of interviews with ten South African National Defence Force members. A self–developed interview schedule was used to establish the parent's knowledge regarding child sexual abuse. The results indicated the limited knowledge of parents in the military regarding child sexual abuse. Many parents viewed sexuality as a taboo topic. Some parents presented with an attitude that someone else is responsible for their child's sexual education. Still, the parents indicated that they would like to improve their communication with their children in order to empower and protect the child against sexual perpetrators. / Thesis (M.A. (MW))--North-West University, Potchefstroom Campus, 2011.

As a developing country, South Africa is in dire need of socio-economic development and upliftment, especially in the light of past inequalities. Mining generates massive amounts of revenue and creates employment for the masses and could therefore contribute successfully towards socio-economic development, especially in a country which is richly endowed with mineral resources. Mining seems unsustainable due to the fact that it leads to the destruction of the natural environment and the depletion of non-renewable resources. Mining companies must nonetheless strive to achieve sustainability. The Constitution stipulates that the State should establish an environmental governance framework to, amongst others, protect the environment and prevent pollution while ensuring justifiable social and economic development. While the Constitution emphasises the importance of the integration, the question remains as to how the notion of sustainable development should be interpreted in a country suffering from severe poverty and a need for social and economic development. The aim of this study is to determine how the sustainability concept within mining and environmental legislation could be interpreted and given effect in order to ensure better environmental governance within the mining sector. This study indicates that the current environmental governance framework regulating the mining industry is fragmented and lacks the necessary criteria to ensure sustainability. For the purposes of this study, a sustainability model was developed for the mining industry along the lines of the different layers of an "onion" to illustrate the interdependence of the different layers of sustainability. To ensure better sustainability within the environmental governance framework, currently regulating the mining industry, sustainability criteria should be developed, clearly indicating how the different layers of sustainable development should be weighed, balanced and integrated by decision-makers. / Thesis (LL.M. (Environmental law))--North-West University, Potchefstroom Campus, 2012.

Invasive Prosopis trees pose significant threats to biodiversity and ecosystem services in the Northern Cape Province of South Africa. Several estimates have been made of the spatial extent of alien plant invasion in South Africa. The South African Plant Invaders Atlas (SAPIA) suggested that about 10 million hectares of South Africa has been invaded. However, the rate and spatial extent of Prosopis invasion has never been accurately quantified. The objective of the study is to use Remote Sensing and Geographic Information System (GIS) techniques to: (i) reveal areas susceptible to future invasion, (ii) describe the current extent and densities of Prosopis, (iii) to reveal the spatial dynamics and (iv) establish the extent of fragmentation of the natural vegetation in the Northern Cape Province. Image classification products were generated using spectral analysis of seasonal profiles, various resolution image inputs, spectral indices and ancillary data. Classification approaches varied by scene and spatial resolution as well as application of the data. Coarse resolution imagery and field data were used to create a probability map estimating the area vulnerable to Prosopis invasion using relationships between actual Prosopis occurrence, spectral response, soils and terrain unit. Multi-temporal Landsat images and a 500m x 500m point grid enabled vector analysis and statistical data to quantify the change in distribution and density as well as the spatial dynamics of Prosopis since 1974. Fragmentation and change of natural vegetation was quantified using a combined cover density class, calculating patch density per unit (ha) for each biome The extent of Prosopis cover in the Northern Cape Province reached 1.473 million hectare or 4% of the total land area during 2007. The ability of the above mentioned Remote Sensing and GIS techniques to map the extent and densities of Prosopis in the Northern Cape Province of South Africa demonstrated a high degree of accuracy (72%). While neither the image classification nor the probability map can be considered as 100% accurate representations of Prosopis density and distribution, the products provide use full information on Prosopis distribution and are a first step towards generating more accurate products. For primary invasion management, these products and the association of a small area on a map with Prosopis plants and patches, mean that the management effort and resources are efficiently focused. Further studies using hyper-spectral image analysis are recommended to improve the classification accuracy of the spatial extent and density classes obtained in this study. / Thesis (M. Environmental Science)--North-West University, Potchefstroom Campus, 2010.

The prevalence of child sexual abuse in South Africa is alarmingly high. Child protection officials’ task is challenging due to the fact that most cases of child sexual abuse are never reported as a result of the stigma attached to child sexual abuse. This article explains the vulnerable position of the children of uniform members of the military due to the fact that one or both parents are absent from the family due to fragmentation. Two main reasons are causing fragmentation. The first reason that can be mentioned is the fact that the soldier him–/herself has decided not to relocate the family to his/her workplace. Cultural beliefs, housing crisis or other practical challenges might play a role in the parent’s decision. The second reason for fragmentation is the fact that soldiers are obliged to attend military courses or to represent their country during a peace operation on the African continent. These military obligations cause physical and emotional absence of the parental figure, which might leave the child in a vulnerable position to fall victim to child sexual abuse. Fragmentation impacts negatively on the parental relationship as well as on the safety of the child. The deployed parent often is left with no choice but to unwittingly leave the child with a harmful caretaker. The aim of the study was to establish the knowledge of parents in the military regarding child sexual abuse. The objectives of the study were: · To investigate parents in the military's basic knowledge of child sexual abuse in preventing their children from falling victim to sexual perpetrators. · To provide guidelines to military parents for preventing and recognising child sexual abuse. Data collection took place by means of interviews with ten South African National Defence Force members. A self–developed interview schedule was used to establish the parent's knowledge regarding child sexual abuse. The results indicated the limited knowledge of parents in the military regarding child sexual abuse. Many parents viewed sexuality as a taboo topic. Some parents presented with an attitude that someone else is responsible for their child's sexual education. Still, the parents indicated that they would like to improve their communication with their children in order to empower and protect the child against sexual perpetrators. / Thesis (M.A. (MW))--North-West University, Potchefstroom Campus, 2011.

As a developing country, South Africa is in dire need of socio-economic development and upliftment, especially in the light of past inequalities. Mining generates massive amounts of revenue and creates employment for the masses and could therefore contribute successfully towards socio-economic development, especially in a country which is richly endowed with mineral resources. Mining seems unsustainable due to the fact that it leads to the destruction of the natural environment and the depletion of non-renewable resources. Mining companies must nonetheless strive to achieve sustainability. The Constitution stipulates that the State should establish an environmental governance framework to, amongst others, protect the environment and prevent pollution while ensuring justifiable social and economic development. While the Constitution emphasises the importance of the integration, the question remains as to how the notion of sustainable development should be interpreted in a country suffering from severe poverty and a need for social and economic development. The aim of this study is to determine how the sustainability concept within mining and environmental legislation could be interpreted and given effect in order to ensure better environmental governance within the mining sector. This study indicates that the current environmental governance framework regulating the mining industry is fragmented and lacks the necessary criteria to ensure sustainability. For the purposes of this study, a sustainability model was developed for the mining industry along the lines of the different layers of an "onion" to illustrate the interdependence of the different layers of sustainability. To ensure better sustainability within the environmental governance framework, currently regulating the mining industry, sustainability criteria should be developed, clearly indicating how the different layers of sustainable development should be weighed, balanced and integrated by decision-makers. / Thesis (LL.M. (Environmental law))--North-West University, Potchefstroom Campus, 2012.